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Environmental Impact Assessment
Proposed Development at
Fung Lok Wai, Yuen Long
Lot 1457 R. P. in D.D. 123
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CH2M HILL Hong Kong Limited
in
association with
RPS
ADI Ltd.
Archaeological
Assessments
MVA Hong Kong Limited
Reference R228-2.07
Client Mutual Luck Investment Limited
Date July
2008
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TABLE OF
CONTENTS
1. Introduction_ 1-1
1.1 Background_ 1-1
1.2 Historical
Land Use of the Site_ 1-1
1.3 Ecological
Importance of Fish Ponds 1-2
1.4 Project
Objective_ 1-2
1.5 Objectives
of the EIA Study 1-2
1.6 Scope of
the EIA_ 1-3
1.7 Structure
of the EIA_ 1-5
2. Project
description_ 2-7
2.1 The
Proposed Development and the Environs 2-7
2.2 Construction
of the Project 2-9
2.3 Potential
Concurrent Projects that Could Lead to Cumulative Impacts 2-14
3. Consideration
of alternatives schemes_ 3-1
3.1 Background_ 3-1
3.2 Identified
constraints 3-1
3.3 Modifications
of the development proposal to meet the identified constraints 3-1
3.4 Shifting
of Residential Development Area_ 3-1
3.5 Alternative
Route for Development Access 3-2
3.6 Establishment
of a potential alternative egretry within the Wetland Nature Reserve_ 3-4
3.7 Consideration
of Alternative Building Heights 3-4
3.8 Comparison
of Development Options 3-5
3.9 The
Preferred Development Option_ 3-8
4. air
quality impact_ 4-1
4.1 Introduction_ 4-1
4.2 Legislation
and Guidelines 4-1
4.3 Ambient
Air Quality 4-2
4.4 Construction
Phase Impact 4-2
4.5 Operational
Phase Impact 4-8
4.6 Conclusion_ 4-9
5. Noise
impact assessment_ 5-1
5.1 Introduction_ 5-1
5.2 Background
Information and Relevant Studies 5-1
5.3 Possible
Cumulative Impact 5-1
5.4 Assessment
Area_ 5-2
5.5 Noise
Sensitive Receivers 5-2
5.6 Construction
Phase Impact 5-3
5.7 Operational
Phase Impact 5-16
5.8 Impacts
Summary and Conclusion_ 5-18
6. Water
quality impact assessment_ 6-1
6.1 Introduction_ 6-1
6.2 Description
of Existing Water Systems and Respective Catchments 6-1
6.3 Characterisation
of Baseline Water & Sediment Quality 6-3
6.4 Existing
and Planned Activities In Relation to Water Systems 6-12
6.5 Identification
of Alteration of Water Systems Arising from the Project 6-14
6.6 Identification
of Existing and Future Water & Sediment Pollution Sources 6-15
6.7 Identification
of Water Sensitive Receivers 6-17
6.8 Water and
Sediment Quality Assessment Criteria and Existing Policies 6-18
6.9 Water and
Sediment Quality Impact Assessment 6-20
6.10 Recommendations
of Mitigation Measures 6-22
6.11 Conclusion_ 6-25
7. Potential
Problem of Biogas_ 7-1
7.1 Introduction_ 7-1
7.2 Assessment
Methodology 7-1
7.3 Field
Sampling and Laboratory Analysis 7-1
7.4 Risk Assessment
Criterion_ 7-2
7.5 Estimation
of potential Gas Emissions 7-3
7.6 Evaluation
of Significance of Potential Gas Emissions 7-6
7.7 Monitoring,
Mitigation and Precautionary Measures 7-7
7.8 Impacts
Summary and Conclusion_ 7-8
8. Sewerage
and Sewage Treatment Implications_ 8-1
8.1 Introduction_ 8-1
8.2 Existing
Sewage Disposal and Treatment Facilities 8-1
8.3 Planned
Sewage Disposal and Treatment Facilities in the Area_ 8-2
8.4 Planned
Population and Sewerage Flows Projections 8-2
8.5 Proposed
Development, Sewerage Options and Projection_ 8-3
8.6 Adequacy
of Existing and Planned Sewerage and Treatment Facilities to accept flows 8-3
8.7 New &
Upgrading Works of Sewerage Systems Required for Either Options 8-4
8.8 Environmental
Impacts of Sewerage Systems 8-5
8.9 Preliminary
Design, Operation and Maintenance Requirements of the Proposed Sewerage System
for Either Options 8-6
8.10 Conclusion_ 8-8
9. Waste
Management_ 9-1
9.1 Introduction_ 9-1
9.2 Legislation
and Guidelines 9-1
9.3 Analysis
of Activities and Waste Generation_ 9-2
9.4 Proposal
for Waste Management 9-7
9.5 Impacts
Summary and Conclusion_ 9-8
10. cultural
heritage impact assessment_ 10-1
10.1 Introduction_ 10-1
10.2 Objectives
of the Cultural Heritage Impact Assessment (CHIA) 10-1
10.3 CHIA
Methodology 10-1
10.4 The Study
Area_ 10-2
10.5 Historical
Buildings and Structures Survey 10-2
10.6 Historical
Landscape Features Survey 10-9
10.7 Summary of
the CHIA Findings and Recommendations 10-11
10.8 References 10-12
11. LANDSCAPE
AND VISUAL IMPACT ASSESSMENT_ 11-1
11.1 Introduction_ 11-1
11.2 Standards
and Legislation_ 11-1
11.3 Landscape and Visual Impact Assessment
Methodology 11-2
11.4 Selection
of the Preferred Option_ 11-7
11.5 Review of
Planning and Development Control Framework 11-15
11.6 Review of
Study on the Ecological Value of Fish Ponds in Deep Bay Area_ 11-20
11.7 Existing
Landscape Context 11-21
11.8 Landscape Impact Assessment 11-22
11.9 Existing
Visual Context and Visual Impacts 11-44
11.10 Cumulative Impacts 11-66
11.11 Mitigation
Measures 11-66
11.12 Programme for Landscape Works 11-72
11.13 Operational (Residual) Landscape and Visual
Impacts 11-86
11.14 Conclusion_ 11-89
12. Fisheries
impact assessment_ 12-1
12.1 Introduction_ 12-1
12.2 Methods 12-2
12.3 Description
of the Physical Environment 12-2
12.4 Baseline
condition_ 12-8
12.5 Impact
Identification and Assessment 12-10
12.6 Fisheries
Mitigation / Compensation Measures 12-15
12.7 Monitoring
and Audit Programme_ 12-15
12.8 Conclusion_ 12-16
12.9 References/
Bibliography 12-16
13. Ecological
impact Assessment_ 13-1
13.1 Introduction_ 13-1
13.2 Description
of the Physical Environment 13-3
13.3 Literature
Review_ 13-6
13.4 Review of
Recognised Sites of Conservation Importance in the Vicinity of Fung Lok Wai 13-7
13.5 Field
Survey Methodology 13-12
13.6 General
Ecological Profile and Evaluation of Valued ecological Components 13-19
13.7 Identification
of Potential Impacts 13-44
13.8 Evaluation
of impacts 13-49
13.9 Mitigation
Measures 13-69
13.10 Identification
and evaluation of residual ecological impacts 13-86
13.11 Ecological
Monitoring and Audit 13-87
13.12 References 13-88
14. Draft
Habitat creation and Management PLan FOR the Wetland NaTure Reserve 14-1
14.1 Study
background and objectives 14-1
14.2 Mitigation
objectives 14-10
14.3 Detailed
design and construction methods 14-15
14.4 Management
Strategy 14-26
14.5 Monitoring
and action plans 14-35
14.6 HCMP
Reporting and Review process 14-39
14.7 References 14-43
15. The Long-term Management OF the Wetland NAture Reserve_ 15-1
15.1 Introduction_ 15-1
15.2 Overview of
Wetland Nature Reserve Management Arrangements 15-1
15.3 Management
of the Wetland Nature Reserve_ 15-2
15.4 Conclusions 15-3
16. Environmental monitoring and audit (EM&A) requirements_ 16-1
16.1 Introduction_ 16-1
16.2 Objectives
of Environmental Monitoring and Audit 16-1
16.3 Summary of
Areas Requiring EM&A_ 16-1
16.4 Air Quality 16-1
16.5 Noise
Monitoring_ 16-2
16.6 Water
Quality 16-2
16.7 Waste
Management 16-2
16.8 Ecology 16-3
16.9 Landscape
and Visual 16-3
16.10 Cultural Heritage_ 16-3
16.11 Implementation
Schedule of Environmental Mitigation Measures 16-3
17. Summary of environmental outcomes and overall conclusion_ 17-1
17.1 Introduction_ 17-1
17.2 Key
Environmental Issues 17-1
17.3 Air Quality
Impact 17-1
17.4 Noise Impacts 17-2
17.5 Water
Quality 17-3
17.6 Potential
Problem of Biogas 17-4
17.7 Sewerage
and Sewerage Treatment Implications 17-4
17.8 Waste
Management 17-5
17.9 Ecological
Impact Assessment 17-6
17.10 Fisheries
Impact Assessment 17-8
17.11 Cultural
Heritage Impact Assessment 17-8
17.12 Landscape
and Visual Impact Assessment 17-9
17.13 Overall
Conclusion_ 17-11
Volume 3
LIST OF APPENDICES
Appendix 1-1 Study
Brief
Appendix 4-1 Calculation
of Particulate Emission Rates for Fugitive Dust Impact Assessment
Appendix 4-2 Typical
FDM Result File for Fugitive Dust Impact Assessment
Appendix 5-1 PME
Equipment Inventory for Construction Noise Impact Assessment
Appendix 5-2 Typical
Calculation Worksheet for Construction Noise Impact Assessment
(Unmitigated Scenario)
Appendix 5-3 Silenced
PME Equipment Inventory for Construction Noise Impact Assessment
Appendix 5-4 Typical
Calculation Worksheet for Construction Noise Impact Assessment
(With Silenced PME)
Appendix 5-5 Reduced
SWL of the PME when noise barriers and machinery enclosures applied
Appendix 5-6 Typical
Calculation Worksheet for Construction Noise Impact Assessment
(Silenced PME with noise barriers and
machinery enclosures)
Appendix 8-1 Sewerage
Impact Assessment
Appendix 10-1 Historical
buildings and Structures Catalogue
Appendix 11-1 Preliminary
Tree Survey Report
Appendix 13-1 Ramsar Classification System for Wetlands
Appendix 13-2 Photographs of each habitat type defined
within the Assessment Area for the proposed development at Fung Lok Wai.
Appendix 13-3 Vegetation survey results, site wide
excluding route of original proposed access road.
Appendix 13-4 Aquatic invertebrates recorded at Fung Lok
Wai during the required survey period.
Appendix 13-5 Odonata
species recorded at Fung Lok Wai during the required survey period.
Appendix 13-6 Butterfly
species recorded at Fung Lok Wai during the required survey period.
Appendix 13-7 Fish
species recorded during surveys at Fung Lok Wai
Appendix 13-8 Amphibian
species recorded during surveys at Fung Lok Wai
Appendix 13-9 Reptile
species recorded during surveys at Fung Lok Wai
Appendix 13-10 Summary
bird survey results from transects T1-5 and T7
Appendix 13-11 Summary
bird survey results from transect T6
Appendix 13-12 Analysis of recent bird records within the
Deep Bay area
Appendix 14-1 Generic
Bund Designs
Appendix 14-2 Water
Budget
Appendix 14-3 Planting
Zones
Appendix 14-4 Specification
for footpaths/ broad walks
Appendix 14-5 Indicative
design of hides
Appendix 14-6 Details
of Floating Platforms
Appendix 16-1 Implementation Schedule of Recommended Environmental Mitigation
Measures
LIST OF ANNEX
Annex A Proposal for the Management of
HKSAR WETLAND NATURE FOUNDATION
LIST OF FIGURES
Figure
1‑1 The Proposed Development 1-6
Figure 2‑1 The
Proposed Development and the
Environs 2-15
Figure 2‑2 Extract
of Tin Shui Wai, Lau Fau Shan & Tsim Bei Tsui Zoning Plan_ 2-16
Figure 2‑3 Tentative
MLP of the Proposed Residential
Development 2-17
Figure 2‑4 The
Assessment Area_ 2-18
Figure 2‑5 Tentative
Layout Plan of Wetland Nature Reserve 2-19
Figure 2‑6 Existing
Drainage and Catchment Area in the Vicinity 2-20
Figure 2‑7 Tentative
Construction Programme for the Project 2-21
Figure 2‑8 The
Proposed Access Road of the Development 2-22
Figure 2‑9 Pond
Numbering System Used Prior to
WNR Establishment 2-23
Figure 2‑10 Pond
Enhancement Sectors of the Proposed WNR_ 2-24
Figure 2‑11 Locations
of New Bunds and the Removal / Modification
Sequence of the Bunds 2-25
Figure 2‑12 Possible
Concurrent Projects in the
Vicinity 2-26
Figure 3‑1 The
Original Preliminary Layout of the Project 3-9
Figure 3‑2 The
Modified Development 3-10
Figure 3‑3a The
Three Building Height Scenarios – Option 1A_ 3-11
Figure 3‑3b The Three
Building Height Scenarios – Option 1B_ 3-12
Figure 3‑3c The Three
Building Height Scenarios – Option 1C_ 3-13
Figure 3‑4 Photomontages
of the Three Building Height Scenarios 3-14
Figure 3‑5 Original Location and Shifted Location of
the Proposed Residential Development 3-15
Figure 4‑1 Location
of Representative ASRs for Construction Dust Impact Assessment 4-10
Figure 4‑2 The
Alignment of Haul Roads, Locations
of Representative Emission Points of Stage A_ 4-11
Figure 4‑3 The
Alignment Of Haul Roads, Locations Of Representative Emission Points Of Stage B_ 4-12
Figure 4‑4 Mitigated
Maximum Hourly Average
TSP Concentrations Predicted at 10.0 mPD under Stage A 4-13
Figure 4‑5 Mitigated
Daily Average TSP Concentrations
Predicted at 5.3mPD under Stage A_ 4-14
Figure 4‑6 Mitigated
Maximum Hourly Average
TSP Concentrations Predicted at 6.3mPD under Stage B 4-15
Figure 4‑7 Mitigated
Maximum Daily average TSP Concentrations Predicted at 6.3mPD under Stage B 4-16
Figure 5‑1 Locations
of the Representative Assessment Point (RAPs) selected for Construction Noise
Impact Assessment 5-19
Figure 5‑2 The
Noise Sensitive Receivers around the Site 5-20
Figure 5‑3 Construction
Area for Access Road, Residential Site and Wetland Nature Reserve 5-21
Figure 6‑1 The
Assessment Area of the Water
Quality Impact Assessment 6-26
Figure 6‑2 Existing
Water Systems and Respective Catchments 6-27
Figure 6‑3 Locations of EPD’s Water Quality Monitoring
Stations in Deep Bay 6-28
Figure 6‑4 Locations of EPD’s Marine Sediment Quality
Monitoring Stations in Deep Bay 6-29
Figure 6‑5 Locations and WQI of EPD’s River Water
Quality Monitoring Stations at Yuen Long Creek and Kam Tin River 6-30
Figure 6‑6 Locations
of Sampling Ponds for Fishpond Water Quality 6-31
Figure 6‑7 Locations
of Sampling Ponds for Fishpond Sediment Quality 6-32
Figure 6‑8 Sampling
Locations for River Water Quality 6-33
Figure 6‑9 21
Larger Ponds will be Consolidated in the WNR_ 6-34
Figure 6‑10 Details
of Marsh Structure 6-35
Figure 6‑11 Drainage
Channel X and Y for Water Discharge in the WNR_ 6-36
Figure 6‑12 Daily
Variation of Rainfall from 1989 to 1998_ 6-37
Figure 6‑13 Discharge
Volume from Water Ponds within the Site from 1989 to 1998_ 6-38
Figure 7‑1 Locations
of Sediment Sampling Ponds for Biogas Investigation_ 7-9
Figure 8‑1 Existing
Sewerage Systems near the Subject Site 8-9
Figure 8‑2 The
YLSTW Effluent Pipelines and its Alternative
of the YLKTSSD Stage 2_ 8-10
Figure 8‑3 The
Sub-catchment of Sewerage Network under Tin Wah Road_ 8-11
Figure 8‑4 Proposed
Sewerage Options 8-12
Figure 8‑5 Total
Flow to Yuen Long STW from 2000
to 2016_ 8-13
Figure 10‑1 Location
of the Study Area in Hong Kong_ 10-13
Figure 10‑2 Aerial
View of Study Area 1949 (GEO Ref.# YO2388) 10-14
Figure 10‑3 Aerial
View of Study Area 1963 (GEO Ref.# YO9690 ) 10-15
Figure 10‑4 Aerial
View of Study Area 2000 (GEO Ref.# CN26484 ) 10-16
Figure 10‑5 Photographs
Illustrating Examples of Structures in the Study Area_ 10-17
Figure 10‑6 Map
Showing the Locations of Historical Structures in Shing Uk Tsuen_ 10-18
Figure 10‑7 Map
Showing the Locations of the Historical Structures in Tai Tseng Wai 10-19
Figure 10‑8a Map Showing
the Locations of the Historical Structures in Ng Uk Tsuen_ 10-20
Figure 10‑8b Map Showing
the Locatios of the Tin Hau Temple near Ng Uk Tsuen_ 10-21
Figure 10‑9 Map
Showing the Locations of Graves and Fung Shui Wood_ 10-22
Figure 10‑10 Aerial
View of the Study Area 1924 (GEO Ref.# Y00159) 10-23
Figure 10‑11 Map
showing the Evolution of the Bunds (1927-2000) and Locations of Existing Bunds Still Following the Original
Alignment 10-24
Figure 10‑12 Photographs
illustrating the Study Area: (A) Example of road hardening; (B) View of the
bunds; (C) View of a sluice gate 10-25
Figure 11‑1A Alternative
Building Height Profiles 11-95
Figure 11‑1B Alternative
Block Plans – Option 1A_ 11-96
Figure 11‑1C Alternative
Block Plans – Option 1B_ 11-97
Figure 11‑1D Alternative
Block Plans – Option 1C_ 11-98
Figure 11‑2 Landscape
Resources 11-99
Figure 11‑3 Preliminary
Tree Survey Plan_ 11-100
Figure 11‑4 Landscape
CharacterAreas 11-101
Figure 11‑5A Landscape
Character Area Photograph_ 11-102
Figure 11‑5B Landscape
Character Area Photograph_ 11-103
Figure 11‑6 Visual
Envelope and Zone of Visual Influence 11-104
Figure 11‑7 Visual
Characteristics of the Study Area_ 11-105
Figure 11‑8 Review
of Planning and Development Control Framework_ 11-106
Figure 11‑9 Impacts
on Landscape Resources Option 1A and 1B_ 11-107
Figure 11‑10A Visual Impacts for Option 1A_ 11-108
Figure 11‑10B Visual Impacts for Option 1B_ 11-109
Figure 11‑11A Design Concept
Drawing and Recommended Landscape Mitigation Measures for Option 1A 11-110
Figure 11‑11B Landscape
Master Plan for Option 1A_ 11-111
Figure 11‑12A Design Concept
Drawing and Recommended Landscape Mitigation Measures for Option 1B 11-112
Figure 11‑12B Landscape
Master Plan for Option 1A_ 11-113
Figure 11‑13A Section A-A’ for Option 1A_ 11-114
Figure 11‑13B Section B-B’ for Option 1A_ 11-115
Figure 11‑13C Section A-A’ for Option 1B_ 11-116
Figure 11‑13D Section B-B’ for Option 1B_ 11-117
Figure 11‑14A Photomontages– Vantage Point A – Option 1A_ 11-118
Figure 11‑14B Photomontages– Vantage Point A – Option 1A_ 11-119
Figure 11‑14C Photomontages– Vantage Point B – Option 1A_ 11-120
Figure 11‑14D Photomontages– Vantage Point B – Option 1A_ 11-121
Figure 11‑14E Photomontages– Vantage Point C – Option 1A_ 11-122
Figure 11‑14F Photomontages– Vantage Point C – Option 1A_ 11-123
Figure 11‑14G Photomontages– Vantage Point D – Option 1A_ 11-124
Figure 11‑14H Photomontages– Vantage Point D – Option 1A_ 11-125
Figure 11‑14I Photomontages– Vantage Point E – Option 1A_ 11-126
Figure 11‑14J Photomontages– Vantage Point E – Option 1A_ 11-127
Figure 11‑14K Photomontages– Vantage Point F – Option 1A_ 11-128
Figure 11‑14L Photomontages– Vantage Point F – Option 1A_ 11-129
Figure 11‑14MPhotomontages– Vantage Point G – Option 1A_ 11-130
Figure 11‑14N Photomontages– Vantage Point G – Option 1A_ 11-131
Figure 11‑14O Photomontages– Vantage Point H – Option 1A_ 11-132
Figure 11‑14P Photomontages– Vantage Point H – Option 1A_ 11-133
Figure 11‑15A Photomontages– Vantage Point A – Option 1B_ 11-134
Figure 11‑15B Photomontages– Vantage Point A – Option 1B_ 11-135
Figure 11‑15C Photomontages– Vantage Point B – Option 1B_ 11-136
Figure 11‑15D Photomontages– Vantage Point B – Option 1B_ 11-137
Figure 11‑15E Photomontages– Vantage Point C – Option 1B_ 11-138
Figure 11‑15F Photomontages– Vantage Point C – Option 1B_ 11-139
Figure 11‑15G Photomontages– Vantage Point D – Option 1B_ 11-140
Figure 11‑15H Photomontages– Vantage Point D – Option 1B_ 11-141
Figure 11‑15I Photomontages– Vantage Point E – Option 1B_ 11-142
Figure 11‑15J Photomontages– Vantage Point E – Option 1B_ 11-143
Figure 11‑15K Photomontages– Vantage Point F – Option 1B_ 11-144
Figure 11‑15L Photomontages– Vantage Point F – Option 1B_ 11-145
Figure 11‑15MPhotomontages– Vantage Point G – Option 1B_ 11-146
Figure 11‑15N Photomontages– Vantage Point G – Option 1B_ 11-147
Figure 11‑15O Photomontages– Vantage Point H – Option 1B_ 11-148
Figure 11‑15P Photomontages– Vantage Point H – Option 1B_ 11-149
Figure 12‑1 Location
and Layout of the Assessment
Area_ 12-18
Figure 12‑2 Sequence
of Pond Enhancement Works 12-19
Figure 13‑1 Site
Outline and Extent of Ecological Assessment Areas 13-92
Figure 13‑2 Location
of Ecologically Sensitive Receivers near the Fung Lok Wai Site 13-93
Figure 13‑3 Vegetation
Survey Quadrat Locations 13-94
Figure 13‑4 Aquatic
Invertebrate Sampling Locations 13-95
Figure 13‑5 Insect
and Herpetofauna Transect Routes 13-96
Figure 13‑6 Freshwater
Fish Survey Locations 13-97
Figure 13‑7 Bird
Survey Transect Locations 13-98
Figure 13‑8 Location
of Current Egretry and Flightline Survey Observers 13-99
Figure 13‑9 Distribution
of Habitat Types within the Study Area_ 13-100
Figure 13‑10 Flight
line Survey Results for the Entire Study Site at Fung Lok Wai 13-101
Figure 13‑11 Flight
Lines Associated with the Fung Lok Wai
Egretry 13-102
Figure 13‑12 Location
of Disturbance Exclusion and Reduced Density Buffers for Waterbird Species of
Conservation Importance during Construction and Operation Phases 13-103
Figure 13‑13 Habitat
Enhancement Work Programme for
The Fung Lok Wai WNR_ 13-104
Figure 14‑1 Location
of the Fung Lok Wai Wetland Nature Reserve 14-45
Figure 14‑2 Average
Monthly Rainfall, Evaporation
and Deficits at Fung Lok Wai. 14-46
Figure 14‑3 Existing
Water Systems and Respective
Catchments 14-47
Figure 14‑4 Broad Layout of the Wetland Nature Reserve 14-48
Figure 14‑5 Details of Habitat Layout within the Wetland
Nature Reserve 14-49
Figure 14‑6 Developments Associated with the Construction
of the Wetland Nature Reserve 14-50
Figure 14‑7 Location
of Aquaculture Pond Habitat Features
and Water Control Structures 14-51
Figure 14‑8 Details of Marsh Habitats and Infrastructure 14-52
Figure 14‑9 Habitats within the Constructed Marsh Area_ 14-53
Figure 14‑10 Status of Storage Pond under Normal and Extreme Rainfall Scenarios 14-54
Figure 14‑11 Management Compartments for the Mai Po and Inner Deep Bay Ramsar Site 14-55
Figure 14‑12 Proposed Layout of Footpaths 14-56
Figure 14‑13 Pond
Enhancement Sectors 14-57
Figure 14‑14 Definition
of Operating Water Levels for Ponds 14-58
LIST OF TABLES
Table
2‑1 Basic
Parameters of the Proposed Residential Development 2-7
Table 2‑2 Habitat
Enhancement Work Programme For The Fung Lok Wai WNR_ 2-12
Table 3‑1 Comparison
of the Two Access Options 3-3
Table 4‑1 Hong Kong Air Quality Objectives 4-1
Table 4‑2 Annual
Average Concentrations of NO2 and RSP measured at EPD’s Air Quality
Monitoring Station in Yuen Long from 2002
to 2006_ 4-2
Table 4‑3 Representative
ASRs for the Dust Emission Impact Assessment 4-4
Table 4‑4 Predicted
Unmitigated TSP Level at selected ASRs 4-5
Table 4‑5 Predicted
mitigated TSP Level at selected ASRs 4-7
Table 5‑1 Noise
Limits for Daytime Construction Activities 5-3
Table 5‑2 Key
Construction Activities for Construction Noise Impact Assessment 5-4
Table 5‑3 Representative
Assessment Phases studied in the Construction Noise Impact Assessment 5-5
Table 5‑4 RAPs
Selected for Construction Noise Impact Assessment 5-7
Table 5‑5 Unmitigated
Noise Levels Predicted At CN 1_ 5-7
Table 5‑6 Unmitigated
Noise Levels Predicted At CN 2_ 5-8
Table 5‑7 Unmitigated
Noise Levels Predicted At CN 3_ 5-8
Table 5‑8 Unmitigated
Noise Levels Predicted At CN 4_ 5-9
Table 5‑9 Unmitigated
Noise Levels Predicted At CN 5_ 5-9
Table 5‑10 Mitigated
Noise Levels at CN1 with Silenced PME_ 5-10
Table 5‑11 Mitigated
Noise Levels at CN2 with Silenced PME_ 5-11
Table 5‑12 Mitigated
Noise Levels at CN3 with Silenced PME_ 5-11
Table 5‑13 Mitigated
Noise Levels at CN4 with Silenced PME_ 5-12
Table 5‑14 Mitigated
Noise Levels at CN5 with Silenced PME_ 5-12
Table 5‑15 Mitigated
Noise Levels at CN1 with Silenced PME + Temporary Noise Barriers + Machinery
Enclosure 5-14
Table 5‑16 Mitigated
Noise Levels at CN2 with Silenced PME + Temporary Noise Barriers + Machinery
Enclosure 5-14
Table 5‑17 Area
Sensitivity Ratings of NSRs 5-17
Table 6‑1 Summary
Statistics of Marine Water Quality of Deep Bay WCZ in 2005 (Inner Deep Bay) 6-4
Table 6‑2 Summary
Statistics of Marine Bottom Sediment Quality of Deep Bay WCZ, 2001 -2005_ 6-5
Table 6‑3 Summary
of River Water Quality Monitoring results for Yuen Long Creek, Kam Tin River
and Tin Shui Wai Nullah in 2005_ 6-7
Table 6‑4 Results
Of Water Quality Monitoring In Fishponds At Fung Lok Wai (1995) 6-9
Table 6‑5 Results
of Fishpond/ River Water Quality Survey at Fung Lok Wai 6-10
Table 6‑6 Results
of Fishpond Sediment Quality Survey at Fung Lok Wai 6-10
Table 6‑7 Estimated
Runoff After Development 6-15
Table 6‑8 Estimated
Peak Rate of Runoff After Development 6-15
Table 6‑9 Water
Quality Objectives for Deep Bay WCZ_ 6-18
Table 6‑10 Classification
of Sediment 6-18
Table 6‑11 Sediment
Quality Criteria for the Classification of Sediment 6-19
Table 6‑12 Summary
of Annual Evaporation and Rainfall (1989 to 1998) 6-20
Table 7‑1 Sampling
Locations and Levels of Total Organic Carbon (TOC) and Sediment Oxygen Demand
(SOD) 7-1
Table 7‑2 Calculation
of Methane Flux from the Fung Lok Wai Development 7-5
Table 8‑1 Development
Schedule the Project 8-2
Table 8‑2 Required
Upgrading of the Sewerage Network Leading to the TWR pumping Station_ 8-5
Table 9‑1 Sumamry
Table of Estimate Quantity of Materials to be Generated or Imported during the
Construction of the Fung Lok Wai Project 9-4
Table 10‑1 The
impacts associated with cultural heritage resources outside the Study Area_ 10-8
Table 10‑2 Mitigation
Recommendations for Cultural Heritage Resources Outside the Study Area_ 10-9
Table 11‑1 Degree of Impact 11-5
Table 11‑2 Residual
Impact Significance Threshold Matrix 11-6
Table 11‑3 Alternative
Schemes Comparison_ 11-10
Table 11‑4 Review
of Existing Planning and Development Control Framework_ 11-17
Table 11‑5 Existing
Landscape Resources and Predicted Impacts – Options 1A and 1B_ 11-25
Table 11‑6 Existing
Landscape Character and Predicted
Impacts – Options 1A and 1B_ 11-37
Table 11‑7A Visually
Sensitive Receivers and Predicted
Impacts – Option 1A_ 11-48
Table 11‑7B Visually
Sensitive Receivers and Predicted
Impacts – Option 1B_ 11-63
Table 11‑8 Proposed Construction Phase Mitigation
Measures 11-67
Table 11‑9 Proposed Operational Phase Mitigation
Measures 11-68
Table 11‑10 Provisional
Programme for Landscape Works 11-72
Table 11‑11 Landscape
and Visual Mitigation Measures Implementation Schedules 11-73
Table 12‑1 Results
of Fishpond/ River Water Quality Survey at Fung Lok Wai 12-4
Table 12‑2 Area
of Ponds and Inland Fresh Fish Production In Hong Kong. Source AFCD Annual
Reports, 2002 12-5
Table 12‑3 Optimum
Water Quality Objectives for
Initiating Fish Rearing_ 12-6
Table 12‑4 Summary
Of Fish Species Typical Of Polyculture Practice In The Deep Bay Area And
Examples Of The Sources Of Stock_ 12-7
Table 12‑5 Production
Time And Acceptable Market Size Of Species Of Fish Raised In Aquaculture Ponds 12-7
Table 12‑6 Extent
of Habitats Identified Within the Fung Lok Wai Assessment Area_ 12-8
Table 12‑7 Wholesale
price range per kg of freshwater fish during the period January – December
2001. Source: AFCD, fax 11/9/02_ 12-11
Table 12‑8 Schedule
for pond enhancement works. Bund numbers are illustrated in Figure 12‑2_ 12-12
Table 12‑9 Summary
of importance of the fisheries resources within the Fung Lok Wai Assessment
Area and evaluation of predicted impacts 12-14
Table 13‑1 Results of Water Quality Monitoring in
Fishponds at Fung Lok Wai (May 2002) 13-5
Table 13‑2 Survey
Time Segments for Bird Flight Line Surveys 13-17
Table 13‑3 Target
Species for Flightline Surveys and Their Species Codes used on Recording Sheets 13-18
Table 13‑4 Altitude Categories Adopted to Record the
Bird Flight Line Data_ 13-18
Table 13‑5 Extent
of Habitat Types within the Assessment Area (ha.) 13-20
Table 13‑6 Ecological
Evaluation Of Intertidal Forested Wetlands 13-21
Table 13‑7 Ecological
Evaluation of Permanent Rivers, Streams and Creeks 13-22
Table 13‑8 Ecological
Evaluation of Ditches and Drainage Channels 13-22
Table 13‑9 Ecological
Evaluation of Aquaculture Ponds 13-23
Table 13‑10 Ecological
Evaluation of Reedbed_ 13-24
Table 13‑11 Ecological
Evaluation of Permanent Freshwater Marsh and Pools 13-24
Table 13‑12 Ecological
Evaluation of Seasonally Flooded (wet) Agricultural Land_ 13-25
Table 13‑13 Ecological
Evaluation of Dry Agricultural Land_ 13-25
Table 13‑14 Ecological
Evaluation of Inactive Agricultural Land_ 13-25
Table 13‑15 Ecological
Evaluation of Orchards 13-26
Table 13‑16 Ecological
Evaluation of Fung Shui Woodland_ 13-26
Table 13‑17 Ecological
Evaluation of Semi-natural Secondary Woodland_ 13-27
Table 13‑18 Ecological
Evaluation of Plantation Woodland_ 13-27
Table 13‑19 Ecological
Evaluation of Grassland_ 13-28
Table 13‑20 Ecological
Evaluation of Grassland-Shrubland Mosaic 13-28
Table 13‑21 Ecological
Evaluation of Landscaped Area_ 13-28
Table 13‑22 Ecological
Evaluation of Wasteland Habitats 13-29
Table 13‑23 Ecological
Evaluation of Recreated Wetland_ 13-29
Table 13‑24 Ecological
Evaluation of Developed Areas 13-30
Table 13‑25 Summary
of habitat evaluations in order of ecological value. 13-31
Table 13‑26 Plant
Species of Potential Conservation
Interest Recorded within the
Assessment Area_ 13-32
Table 13‑27 Reptile
Species of Some Conservation Value, Their Habitat Preferences and Observed
Relative abundance within the Assessment Area at Fung Lok Wai 13-35
Table 13‑28 Bird
Species of Conservation Importance Recorded in Significant Numbers within the
Assessment Area of Fung Lok Wai 13-37
Table 13‑29 List
of Bird Species of Conservation Importance Recorded in Each Section of the
Assessment Area at Fung Lok Wai. 13-40
Table 13‑30 Abundance and Proportion of Birds Observed
Within the Study Site by Altitude Category (February-December 2001) 13-41
Table 13‑31 Dominant Species by Altitude Category 13-41
Table 13‑32 Comparison
of Total Individuals for Each Altitude Category within the Study Site and the
Proposed Development Area_ 13-41
Table 13‑33 Abundance and Proportion of Birds Observed
within the Proposed Development Area by Altitude Category (February-December
2001) 13-42
Table 13‑34 Dominant
Species Recorded at Each Altitude Category within the Proposed Development Area 13-42
Table 13‑35 Comparison
of Potential Affect on Egretry Flightlines of Alternative Development Scenarios 13-46
Table 13‑36 Summary
Matrix of Potential Impacts on Various
Types of Habitats 13-49
Table 13‑37 Summary
of Impacts to Aquaculture Ponds from Habitat Loss 13-50
Table 13‑38 Summary
of Impacts to Ditches and Drainage Channel from Habitat Loss 13-51
Table 13‑39 Summary
of Impacts to Wetland Mosaic Habitats (Including Wet Agriculture, Reedbed, and
Freshwater Marsh) from Habitat Fragmentation_ 13-51
Table 13‑40 Summary
of Impacts to Fung-shui Woodland from Habitat Fragmentation_ 13-52
Table 13‑41 Summary
of Impacts to Aquaculture Ponds from Disturbance 13-53
Table 13‑42 Summary
of Impacts to Fung Shui Woodland (Including Egretry) from Disturbance 13-53
Table 13‑43 Summary
of Impacts to Intertidal Forested Wetland from Disturbance 13-54
Table 13‑44 Summary
of Impacts to Wetland Mosaic Habitats (including Wet Agriculture, Reedbed, and
Freshwater Marsh) from Disturbance 13-54
Table 13‑45 Summary
of Impacts to Dry/Inactive Agricultural Land from Disturbance 13-54
Table 13‑46 Summary
of impacts to Semi-natural Secondary Woodland from Disturbance 13-54
Table 13‑47 Summary
of Impacts to Aquaculture Ponds from Pollution_ 13-55
Table 13‑48 Summary
of Impacts to Fung-shui Woodland (including Egretry) from Pollution_ 13-56
Table 13‑49 Summary
of Impacts to Intertidal Forested Wetland from Pollution_ 13-56
Table 13‑50 Summary
of Impacts Wetland Mosaic Habitats (including Wet Agriculture, Reedbed, and
Freshwater Marsh) from Pollution_ 13-56
Table 13‑51 Summary
of Impacts to Dry/Inactive Agricultural Land from Pollution_ 13-57
Table 13‑52 Summary
of Impacts to Semi-natural Secondary Woodland from Pollution_ 13-57
Table 13‑53 Summary
of Impacts to Aquaculture Ponds from Soil Compaction_ 13-57
Table 13‑54 Summary
of Impacts to Ditches and Drainage Channels from Hydrological Disruption_ 13-58
Table 13‑55 Predicted
Disturbance Impacts from the Construction and Operation of the Residential
Development on Regularly Occurring Species of Conservation Importance at Fung
Lok Wai 13-62
Table 13‑56 Habitat
Loss During the Construction Phase on Regularly Occurring Species of
Conservation Importance at Fung Lok Wai 13-63
Table 13‑57 Habitat
Loss during the Operation Phase on Regularly Occurring Species of Conservation
Importance at Fung Lok Wai 13-65
Table 13‑58 Significance
of impacts on Species of Conservation Importance at Fung Lok Wai 13-68
Table 13‑59 Observed
maximum, mean (counts and densities) of wetland bird species using the wetland
in the Study Site and Assessment Area during 2001_ 13-72
Table 13‑60 Extent
and proportion of direct and indirect (due to disturbance) habitat loss during
construction for sensitive wetland bird species. 13-73
Table 13‑61 Mitigation
targets for key wetland bird species of conservation importance within
remaining wetland areas of the Study Site required to fully compensate for
habitat loss and disturbance impacts during construction_ 13-74
Table 13‑62 Extent
and proportion of direct and indirect (due to disturbance) habitat loss during
operation for wetland bird species 13-77
Table 13‑63 Mitigation
targets for wetland bird species of conservation importance within remaining
wetland areas of the Study Site required to fully compensate for habitat loss
and disturbance impacts during operation 13-78
Table 13‑64 Mitigation
Targets for Enhanced Aquaculture Ponds 13-79
Table 13‑65 Mitigation
Targets for Marsh Habitat 13-80
Table 13‑66 Bird
SpeciesExpected to Use the Marsh Habitat 13-80
Table 13‑67 The Overall Levels Of Compensation Predicted
From Compensation Measures For Species Of Conservation Importance That Were
Recorded During The Baseline Surveys At Fung Lok Wai 13-84
Table 13‑68 Proposed Mitigation Measures and Predicted
Residual Impacts 13-86
Table 13‑69 Mitigation targets for Key Bird Species and
other Species of Conservation Importance 13-87
Table 14‑1 Ecological
evaluation of habitats within the Fung Lok Wai Assessment Area_ 14-4
Table 14‑2 Species
of Conservation Importance that occur within the Fung Lok Wai Assessment Area 14-5
Table 14‑3 Summary
matrix of potential impacts on habitats 14-7
Table 14‑4 Potential
physical constraints on the creation of a Wetland Nature Reserve at Fung Lok
Wai. 14-7
Table 14‑5 Mitigation targets for enhanced fishponds 14-12
Table 14‑6 Mitigation targets for Marsh Habitat 14-13
Table 14‑7 Mitigation targets for Species of
Conservation Importance associated with fishpond habitats 14-13
Table 14‑8 Species Expected to Use the Marsh Habitat 14-14
Table 14‑9 The area of habitats in the proposed WNR_ 14-15
Table 14‑10 Pond enhancement schedule. 14-18
Table 14‑11 Wetland species to be established in the
aquaculture pond mitigation area_ 14-19
Table 14‑12 Species to be established in the Marsh
Habitat area_ 14-24
Table 14‑13 Long-term
pond management (5 year cycle) 14-32
Table 14‑14 General
management actions for the Fung Lok Wai WNR_ 14-33
Table 14‑15 Ecological monitoring programme for Fung Lok
Wai WNR_ 14-36
Table 14‑16 Key
Action Levels and Limits and their associated management actions 14-40
1.1.1
The Project Proponent - Mutual
Luck Investment Limited (MLI), proposes to develop a residential development
and a Wetland Nature Reserve (“WNR”) (hereinafter collectively called the
“Project”) at existing fishponds at Lot 1457
R.P., D.D. 123 Fung Lok Wai, (the Subject Site). The Project comprises the
following main components: -
·
About 4 ha of residential land for 148,000m2 GFA residential
development and a club house for residents;
·
About 76 ha of enhanced and managed WNR, including a
potential alternative egretry.
1.1.2
The entire development will be
about 80 ha in size. The about 4 ha of residential land will be formed
by filling fishponds at the southern part of the site, whilst the WNR will be
established to its immediate north. The Project complies with the “no-net-loss
in wetland” principle stipulated in the notes of the Approved Lau Fau Shan
and Tsim Bei Tsui OZP No. S/YL/-LFS/7.
1.1.3
This is achieved through
enlargement of existing fishponds by removal of part of the dividing bunds. The
Project is scheduled to be completed and with population intake in third
quarter of 2016.
1.1.4
The Subject Site abuts the Inner Deep
Bay and lies within the Wetland
Conservation Area. About 43 ha of the Site has been designated as
a Mai Po Inner Deep
Bay Ramsar Site since September 1995. The Site is close to the Hong Kong
Wetland Park (HKWP), with Mai Po
area to its northeast and Yuen Long Industrial Estate (YLIE) to southeast.
1.1.5
The existing Fuk Shun Street at the southern side of
the Subject Site will be used as the access road of the Project. The location
of the Project, the site boundary and the proposed access road are shown as Figure 1‑1
1.1.6
This Project is a Designated
Project according to Item P of Part I, Schedule 2 of the EIA Ordinance, since
it is a residential development other than New Territories
exempted house within the Deep Bay Buffer Zone 1 and 2.
1.1.7
MLI submitted an application
(No. ESB-055/2000) for an Environmental Impact Assessment (EIA) Study Brief
under section 5(1)(a) of the Environmental Impact Assessment Ordinance (EIAO)
on 26 May 2000 with a project profile (No. PP-091/2000).
1.1.8
A Study Brief [No.
ESB-055/2000] was issued by the Authority to the MLI under Section 5(7)(a) of
the EIAO in July 2000 for preparation of the EIA report. A copy of the Study Brief is given in
Appendix 1-1 for reference.
1.1.9
CH2M HILL Hong Kong Limited, formerly traded as CH2M-IDC Hong Kong Limited, has been
commissioned by the MLI on 16 November 2000 as the lead consultant to carry out
this EIA in associated with RPS, Asia Ecological Consultant, ADI Ltd.,
Archaeological Assessments and MVA Hong Kong Limited.
1.1.10
This EIA report is prepared in
accordance with the requirements stated in the Study Brief and the relevant
criteria and guidelines as stated in various Annexes of the EIA TM.
1.2.1
The earliest useful map
indicated that the area of Fung Lok Wai was swamp and marsh in the early 1900’s. The area was then reclaimed for
brackish water rice cultivation. During
the period between 1938 and 1945, the Deep Bay
area was transformed into gei wais. By
1974, the area was converted to deep water fish ponds as fish farming was then
a profitable business. These fish ponds
remain up to the present, however many of them have been abandoned as a result
of severe competition from the cheap fish imports from mainland China.
1.3.1
Fresh water fish farming was
once an important agricultural activity in Deep Bay
area supporting the livelihoods of many local people. These fish ponds, it so happened, also served
as an extensive area of wetland habitat that are of ecological importance to
birds, in particular to migratory birds on their migratory path as a refuelling
station.
1.3.2
The Fish Pond Study identified
that the traditional aquaculture management practices adopted in the fish ponds
within Deep Bay were of particular ecological value
to wetland birds when the ponds were drained at harvest time. These water birds feed on trash fish that are
of no commercial value and which are bi-product of traditional aquaculture
management practices.
1.3.3
However, with the continual
decline of the fish farming industry in Hong Kong throughout the past decades,
many of the fish ponds in Deep
Bay area are
abandoned. With the absence of active
management, the ecological value of fish ponds to birds will be lost. Therefore, there is an imminent need to
conserve these fish ponds together with the traditional aquaculture management
practices in order to conserve the ecological value of this important wetland
habitat in Deep Bay.
1.4.1
The objective of the Project is
to develop a sustainable model for the conservation of the existing fish ponds
together with the traditional aquaculture management practices with value
creation stemming from the development of a residential complex.
1.4.2
Three major principles are
proposed to be upheld in the design of the Project:
·
No net loss of wetland;
·
Sustainability;
·
Wise use of the wetland.
1.4.3
These principles are embedded
in the physical design of the Project and the proposed operation of the Wetland
Nature Reserve:
No net loss of wetland
1.4.4
The Project will comply with
the “no-net-loss in wetland” principle as stipulated in the notes of the
Approved Lau Fau Shan and Tsim Bei Tsui OZP No. S/YL/LFS/7. The fishponds will be re-profiled and
enlarged through removal of some pond bunds to result in a habitat more
suitable and sympathetic to wetland birds.
A corollary in doing so (enlargement and removal of pond bunds) also
resulted in complying with the “no net loss in wetland” principle as there will
be a slight overall increase in water body area. The residential development site will be
restricted to occupy only 5% of the Site at the southern edge.
Sustainability
1.4.5
The enhanced fish ponds and
habitats created will form a dedicated Wetland Nature Reserve. The Proponent will be responsible for the
creation, enhancement and management of the Wetland Nature Reserve during the
construction phase and shall provide an undertaking to take sole responsibility
for management until a successor, such as an independent Foundation, is
identified to the satisfaction of EPD or its agent.
Wise use of wetland
1.4.6
The long-term management of the
fish ponds in the Wetland Nature Reserve ensures the preservation of the
cultural practice of aquaculture in-situ, which is consistent with concepts of
“wise use” fore-shadowed in Article 3.1 of the Ramsar Convention. It also
provides opportunities for ongoing research into sustainable fish production
and wildlife conservation.
1.5.1
The main objective of this EIA
study is to provide information on the nature and extent of environmental
impacts arising from the construction and operation of the proposed designated
projects and related activities taking place concurrently. The study will
provide information for DEP’s decisions on:
·
Overall acceptability of any
adverse environmental consequences that are likely to arise as a result of the
proposed project;
·
Conditions and requirements for
the detailed design, construction and operation of the proposed project to
mitigate against adverse environmental consequences wherever practicable; and
·
Acceptability of residual
impacts after the proposed mitigation measures are implemented.
1.5.2
The objectives of this EIA
study, as stated in Section 2.1 of the Study Brief, are as follows:
·
To describe the proposed
project and associated works together with the requirements for carrying out
the proposed project;
·
To identify and describe the
elements of the community and environment likely to be affected by the proposed
project and/or likely to cause adverse impacts to the proposed project,
including both the natural and man-made environment;
·
To identify and quantify all
environmental sensitive receivers, emission sources and determine the
significance of impacts on sensitive receivers and potential affected uses;
·
To identify and quantify any
potential losses or damage to flora, fauna and wildlife habitats;
·
To identify any negative
impacts on sites of cultural heritage and to propose measures to mitigate these
impacts;
·
To identify and quantify any
potential landscape and visual impacts and to proposed measures to mitigate
these impacts;
·
To propose the provision of
infrastructure or mitigation measures so as to minimize pollution,
environmental disturbance and nuisance during construction and operation of the
project;
·
To identify, predict and
evaluate the residual (i.e. after practicable mitigation) environmental impacts
and the cumulative effects expected to arise during the construction and
operation phases of the project in relation to the sensitive receivers and
potential affected uses;
·
To identify, assess and specify
methods, measures and standards, to be included in the detailed design,
construction and operation of the project which are necessary to mitigate these
environmental impacts and reducing them to acceptable levels;
·
To investigate the extent of
side-effects of proposed mitigation measures that may lead to other forms of
impacts;
·
To identify constraints
associated with the mitigation measures recommended in the EIA study;
·
To identify, within the study
area, any individual project(s) that fall under Schedule 2 and/or Schedule 3 of
the EIA Ordinance; to ascertain whether the findings of this EIA study have
adequately addressed the environmental impacts of those projects; and where
necessary, to identify the outstanding issues that need to be addressed in any
further detailed EIA study; and
·
To design and specify the
environmental monitoring and audit requirements, if required, to ensure the
implementation and the effectiveness of the environmental protection and
pollution and pollution control measures adopted.
1.6.1
Clause 3.2 of the Study Brief sets out the
scope of the EIA study for the Project and associated
works. The EIA study covers the combined impacts of all the proposed
developments and the cumulative impacts of the existing, committed and planned developments in
the vicinity of the Project including the Hong Kong Wetland
Park, Mai Po Inner Deep Bay
Ramsar Site etc., in accordance with the requirements laid down in Section 3.4
of the TM. The environmental impacts of on-site and off-site works and
facilities associated with the proposed developments shall be addressed. The
EIA study shall address the likely key issues described below, together with
any issues identified during the course of the EIA study:
·
Noise impacts arising from
construction and operation of the development to the nearby village areas;
·
Dust impacts arising from
construction of the development to the nearby villages;
·
Landscape and visual impacts
during construction and operation of the development;
·
Water quality impacts during
construction and operation, including pond draining and filling, sewage
collection, treatment and disposal systems, surface runoff and land drainage
and stormwater system;
·
Potential impacts on historical
buildings/architectures and monuments;
·
Wetland loss and impacts to the
adjacent fishponds, Hong Kong Wetland Park, Recognized Sites of Conservation
Importance including Wetland Conservation Area, Wetland Buffer Area and Mai Po Inner Deep Bay Ramsar Site
due to the construction and operation of the proposed development;
·
Terrestrial and aquatic
ecological impacts to the adjacent area with conservation importance and
ecologically sensitive areas including the Hong Kong Wetland Park, Mai Po Inner Deep Bay
Ramsar site with particular attention to possible fragmentation of the wetland,
ecological link between Deep Bay area and the project area, the future
buildings on the site to the bird’s flight line with special attention to the
ambient light at night-time and the little woodland to the north of Fung Lok
Wai;
·
Fisheries impacts during
construction and operation of the development;
·
Collection and disposal of
potentially contaminated dredged spoil arising from the project; and
·
Proposals for the short term
and long term management of the proposed Wetland Nature Reserve with the
project area including trust and financial arrangement.
1.7.1
The structure of this EIA is as
follows:
Volume 1
Section 1 Introduction
Section 2 Project Description
Section 3 Consideration of Alternative Schemes
Section 4 Air Quality Impact Assessment
Section 5 Noise Impact Assessment
Section 6 Water Quality Impact Assessment
Section 7 Potential Problem of Biogas
Section 8 Sewerage and Sewage Treatment
Implications
Section 9 Waste Management
Section 10 Cultural Heritage Impact Assessment
Section 11 Landscape and Visual Impact Assessment
Volume 2
Section 12 Fisheries Impact Assessment
Section 13 Ecological Impact Assessment
Section 14 The Habitat Creation and Management Plan
of the Wetland Nature Reserve
Section 15 The Long-term Management of the Wetland
Nature Reserve
Section 16 Environmental Monitoring and Audit
Requirements
Section 17 Summary of Environmental Outcome and
Overall Conclusion
2.1.1
The Subject Site is located at Lot 1457 R.P. in D.D. 123, Fung Lok Wai, Yuen Long and is about 2 km north of the Yuen Long New Town. To
the west of the subject site is the Hong Kong Wetland Park (HKWP), with Mai Po located to its northeast
and Yuen Long Industrial Estate (YLIE) to southeast. The total site area is
about 80.1 ha. Figure
2‑1 shows the proposed Project and its environs.
2.1.2
As per the latest Approved Lau
Fau Shan & Tsim Bei Tsui Zoning Plan No. S/YL-LFS/7 gazetted on 1 February
2005, the Subject Site is zoned “Other Specified Uses (Comprehensive
Development and Wetland Enhancement Area)”. Figure
2‑2 refers. Pertaining to the Approved Outline Zoning
Plan of Tin Shui Wai Plan No. S/TSW/11
gazetted on 26 October 2007, the planned zoning areas in the
Tin Shui Wai Reserve Zone are also presented in the same figure.
2.1.3
The Subject Site abuts the Inner Deep
Bay and lies within the
Wetland Conservation Area. About 43 ha
of the Site has been designated as a Mai Po Inner Deep Bay Ramsar Site
since September 1995.
The Residential Development
2.1.4
The proposed residential
development has the following basic parameters as tabulated below.
Table 2‑1 Basic
Parameters of the Proposed Residential Development
|
Total Site Area (approximate)
|
80.1 ha
|
|
Area of
residential development (approximate)
|
4 ha
|
|
Area of
wetland nature reserve (approximate)
|
76.1 ha
|
|
Proposed Plot Ratio
|
0.185
|
|
Proposed Residential GFA
|
148,000 m2
|
|
Design Population
|
8,490
|
|
No. of Flats
|
Not more
than. 2,860 units
|
2.1.5
The about 4 ha residential site will be formed by
filling the fishponds at the southern part of the Subject Site with a WNR to be
established to its north. Vehicular access to the Project will be via the
existing Fuk Shun Street.
The whole residential site lies outside the Mai Po Inner Deep Bay
Ramsar Site.
2.1.6
Figure 2‑3 presents a tentative master layout plan of the
proposed residential development.
The Access Road
2.1.7
The proposed vehicular access
of the site, viz. the Southern Development Access, will be via the existing Fuk Shun Street and
Yuen Long Industrial Estate to
Yuen Long. Fuk
Shun Street is currently a substandard road. The
project proponent is proposing to upgrade this sub-standard Fuk Shun Street to a standard of not less
than 7.3 m single
2-lane public road with not less than 2m
wide footpath on both sides of the road.
2.1.8
The EIA Study Brief stipulates
in general an assessment area of 300m
and 500m from the
boundary of the project site including the access road with respect to noise
and air quality impact assessment respectively. Figure 2‑4 shows these boundaries.
The Wetland Nature Reserve
2.1.9
The WNR will be established on
the remaining 95% (about 76.1 ha.)
of the site unaffected by the residential development. The WNR lies within
Wetland Conservation Area while approximately half of the WNR lies within the Mai Po Inner Deep Bay
Ramsar Site. The northern boundary adjoins the Inner Deep Bay Site of Special
Scientific Interest (SSSI).
2.1.10
The goal of the WNR is to
provide a permanent purpose-built nature reserve and compensate for any
disturbances associated with the construction and operation of the residential
development. The result will be no net loss in either area or function of
wetland habitat.
2.1.11
No net loss in waterbodies area
will be achieved through reconfiguration of fishponds to create fewer, larger
but more suitable ponds for birds and the creation of a complex of freshwater
marsh habitats. Increasing fishpond size has an additional benefit, as there is
evidence that many wetland birds prefer larger, less enclosed water bodies to
small ponds, which typify most aquaculture practices. The removal of some bunds
is predicted to have low or negligible impact as their intrinsic ecological value
is low. The complex of freshwater marsh habitats proposed will provide a range
of additional habitats for birds and other flora and fauna, including
dragonflies.
2.1.12
Functional enhancement will be
achieved through enhancement of both the ponds and the approach to aquaculture
management. The carrying capacity of fishponds is limited by the uniform design
of ponds and management that is not specifically targeted at conservation.
Modifications to both will significantly improve foraging opportunities for
birds and other fauna. To ensure ongoing functional replacement, key ecological
indicators, including birds, will be monitored to guide management of the
reserve.
Outline Design of Wetland Nature Reserve
2.1.13
The proposed WNR will comprise
two key elements (Figure
2‑5):
·
A large expanse of retained,
but ecologically enhanced, fishponds; and,
·
An area of re-created ‘natural’
marshland.
2.1.14
Actively managed ponds in the Deep Bay
area are currently full for most of the year and their use by birds is severely
limited due to their relatively steep sides, deep water and their frequent lack
of marginal vegetation. These characteristics also limit their use by other
species and hence fishponds tend to have relatively low biodiversity compared
to many wetland habitats.
2.1.15
The active management of
fishponds for commercial purposes, however, creates a key by-product in the form of
abundant “trash fish” – small, non-commercial fish and invertebrates. When ponds are drained down during the winter
months for harvesting, large concentrations of birds can be observed foraging
in the shallow water for trash fish. As only a small proportion of fishponds
are drained at any one time, and only for short periods, the spatial
distribution of feeding birds is highly dynamic and variable as birds seek out
ponds as they are drained. ‘Feeding bottlenecks’ may occur if there are
insufficient ponds to support foraging bird populations.
2.1.16
Although much of the Assessment
Area is composed of wetland habitats in the form of aquaculture ponds, poor
water quality and unsympathetic pond design severely limit its value for most
faunal groups. Furthermore, there is inadequate vegetation cover on the site to
support breeding populations of most wetland birds.
2.1.17
The main objectives of
enhancing fishponds are, therefore, to:
·
Increase the value of fishponds
to herons and egrets outside harvesting periods (i.e. draw-down), by increasing
food resources and food availability and by reducing disturbance effects.
Enhancement of the value of fishponds to such birds outside harvest periods
could reduce the potential for ‘feeding bottlenecks’ thereby possibly reducing
the area of fishponds needed to support the population.
·
Increase their overall
biodiversity value and suitability for other non-bird Species of Conservation
Importance, such as some mammals (e.g. Eurasian Otter), amphibians and
reptiles, whilst maintaining their current important functions for herons,
egrets and other water birds.
2.1.18
The ponds will be enhanced
through the following specific actions:
·
The size of the fishponds will
be increased by re-profiling unwanted bunds.
·
Emergent vegetation will be
allowed to develop.
·
Areas of shallow water and
intermittently exposed muddy islands will be created.
2.1.19
The enhanced fishponds will be
located away from the residential development area to minimise disturbance
impacts. They will also be contiguous with the main area of fishponds in the
WCA and Mai Po
Inner Deep Bay Ramsar site as a
whole. Maintaining a contiguous area for compensation, which is linked, with an
existing area of recognized conservation importance is of significant
ecological value.
2.1.20
The natural wetland area will
consist of a marshland complex, including areas of shallow open mesotrophic
water (i.e. of moderate nutrient status), with adjoining reed beds and other
emergent vegetation, shallow margins, islands, irregular shorelines, and an
area of seasonally inundated grazed marsh and pools. Such fresh water marshes
are a scarce habitat in Hong Kong and would
develop rich and abundant aquatic and emergent plant communities. This in turn
may support rich invertebrate, amphibian and reptile communities.
2.1.21
There are three key features of
this proposed layout:
·
The majority of the fishponds
on site are maintained, including all those within the Mai Po Inner Deep Bay Ramsar site
boundary. This avoids the loss or detrimental modification of any wetland area
within the Mai Po Inner
Deep Bay Ramsar site and maintains the large open contiguous block of fishpond
habitat in the area.
·
The location of the proposed area for the re-creation of
natural wetlands will maximise the potential for ecological links with the
following complementary adjacent habitats:
o
Scrub and woodland habitats on the hillsides to the south
of the site;
o
Inter-tidal mangrove habitats along the former Tai River
outfall; and,
o
The wetland creation at Hong Kong Wetland Park (HKWP).
o
These habitats may provide sources for the natural spread
and establishment of some plants and animals within the wetland area. In
addition they will provide additional shelter, food or breeding sites for
wetland species and ecological ‘corridors’, which may facilitate dispersal.
·
As the re-created wetland will contain abundant tall reed
beds, as well as other tall wetland vegetation and scattered trees, this will
serve as a buffer between the residential development and the fishponds. This
will reduce disturbance of birds feeding within the fishponds.
2.2
Construction of the Project
Preliminary Construction Program
2.2.1
Figure 2‑7 shows the tentative construction programme of the
Project. Construction activities are planned to commence in the 3rd quarter of
2010 for completion in the 3rd quarter of 2016. i.e. a total of 6 years.
Assessments of potential construction phase environmental impacts have been
carried out based on this assumed construction programme. While the actual
construction programme may require adjustment during the detailed design stage,
the relevant assessments as presented in this report will allow the identification
of sufficient mitigation measures at an early planning stage. Implementation of
sufficient environmental mitigation measures would be audited through an
Environmental Monitoring and Audit (EM&A) Programme.
2.2.2
The construction programme
consists of the following three main phases: -
·
First phase (3rd quarter of 2010 to 2nd
quarter of 2013) - establishment of the WNR. Key construction activities to be
carried out include:
o
Relocating water from Sector 1,
Sector 2 and Sector 3 ponds at different phases;
o
Draining, removing bunds and
installing water controls at Sector 1, Sector 2 and Sector 3 of the WNR at
different phases;
o
Re-filling ponds at Sector 1,
Sector 2 and Sector 3 of the WNR;
o
Selective felling and
vegetation management at Sector 1, Sector 2 and Sector 3 of the WNR at
different phases;
o
Land formation and water
control structures construction of the Marshland area;
o
Habitat creation of the
Marshland area;
o
Constructing facilities of the
Marshland area, such as board walks, hides, toilets and shelters.
·
Second phase (2nd quarter of
2011 to 3rd quarter of 2016) - construction works for development area.
Key construction activities to be carried out are listed below:
o
Site clearance for the
construction works for development area;
o
Pond draining and dredging at
built area;
o
Delivery of fill material by
trucks to the site;
o
Spreading and compaction of
fill material at built area;
o
Foundation and superstructure
works for buildings;
o
Construction of sewage pump
house;
o
Laying of drainage, sewerage
and utilities;
o
Paving of internal access road.
·
Third phase (4th quarter of 2014 to 3rd
quarter of 2016) – widening works of the access road leading to the Project site.
Key construction activities include:
o
Site clearance and formation
for the widening of the Access Road leading to the site;
o
Laying of drainage, sewerage
and utilities;
o
Formation of road sub-base,
levelling and compaction;
o
Road paving and installation of
road furniture;
o
Construction of landscape
works;
o
Soft landscape establishment
works
2.2.3
The above activities are
categorized and described below.
Establishment and Management of Wetland
Nature Reserve
2.2.4
Except for the residential
portion, the remaining fishponds at the site will be modified and converted
into a WNR. The pond bunds will be re-profiled to provide shallow sloping and
irregular margins to increase feeding opportunities and efficiency for herons,
egrets, waders, rails and crakes etc.
2.2.5
Thirty-seven (approximately 61.7 ha) of the existing fish ponds will be
modified and enhanced to increase their value for Species of Conservation
Importance, particularly birds recorded regularly on the site.
2.2.6
Thirty-one out of these 37
ponds will be consolidated through bund removal to create 18 ponds with an
average size of about 2.6 ha.
These ponds will undergo a series of enhancement to improve their
attractiveness to wildlife, particularly birds including:
·
Creation of shallows and muddy
islands through re-distribution of bund material; and,
·
Cut back of vegetation.
2.2.7
The remaining six ponds will be
consolidated into three and permanently set aside and planted, to varying
degrees, with reeds (Phragmites australis) to provide attractive habitat for
water birds, particularly duck and reed bed passerines. These ponds will be fed
by rain water and their level allowed to fluctuate seasonally.
2.2.8
An area of approximately 14.4 ha adjacent to the development area will
be converted into a complex of freshwater marsh habitats. This area will
comprise:
·
Permanent marsh composed of a series of
shallow inter-locking lakes with occasional deep areas and islands.
·
Seasonal marsh composed of vegetation
that is inundated only during the wet season.
·
Storage pond. The water deficit usually
experienced every dry season is a constraint on the design and management of
marsh habitats. To ensure a supply of freshwater of suitable quality for the
permanent marsh throughout the year an existing fishpond will be enlarged to
provide storage. The optimum size of this storage has been established through
modelling of typical and extreme rainfall patterns.
2.2.9
A potential alternative egretry
will be constructed in a part of the WNR that is as remote as possible to
minimise disturbance.
2.2.10
Water levels within the marsh
complex will be managed according to broad habitat requirements – i.e.
permanent or seasonal inundation. Within the permanently inundated marsh areas,
levels will still be allowed to fluctuate (within bounds) to facilitate the
periodic exposure of muddy areas.
2.2.11
The water supply to the natural
wetland will be from direct rainfall supplemented by run-off from the
residential development and catchments A and B (see Figure 2‑6). Run-off from the residential site and catchments A
and B will enter the storage pond via a ditch running along the southern border
of the development area. The natural wetland area will not flood surrounding
land and residential developments. The lakes within the area will eventually
discharge via Channel X or, during storm events, via Channel Y (see Figure 2‑6) into the Tai
River outfall.
2.2.12
Figure 2‑5 illustrates the proposed design for the Fung Lok Wai
WNR in the context of its surrounding. By adopting the design, there will be no
net loss of but a slight increase in waterbodies area. Figure 2‑10 presents the areas of various habitats, both before
and after the implementation of the ecological enhancement works.
2.2.13
In order to minimise
disturbance, the intensity of the establishment works of WNR will be kept low,
for site clearance works at fishponds where the proposed WNR lies, only a few
ponds will be drained each time for dredging and filling, to ensure the
ecological value of the area can still be maintained during the construction
phase. It is intended that construction works in the WNR requiring heavy
equipment be focused in the the dry season because experience gained during the
construction of the Hong Kong Wetland Park indicates that the substrate may be
too soft for heavy machinery to rework the ponds into the required profile
during the wet season.
2.2.14
Works on the ponds will involve
relatively small machinery as are used during the fishpond farming cycle. Works
can be kept within each individual pond after draining down as occurs during
fishpond farming operations.
Work Programme
2.2.15
The programme and stages of
construction are described in detail in Section 14 of this report.
2.2.16
An outline list of the main
actions necessary for the creation of the marshland and enhancement of the fish
pond habitats is provided in Table
2‑2. Time periods, start and completion dates for these
actions are dependent on the overall residential area construction programme,
which has yet to be finalised.
2.2.17
Prior to construction works
associated with the Residential Development and the WNR all ponds will continue
to be managed under their existing aquaculture regime (aquaculture production).
2.2.18
The broad strategy proposed is
to stage enhancement works to reduce disturbance and to complete habitat
enhancement works within the northern part of the site before construction of
the residential development (in the southern part of the site) commences.
2.2.19
The first stage will involve,
enhancement works in the 13 existing ponds located within Sector 1 (Figure 2‑10). Once these works are complete then work can
commence on ponds within Sector 2.
2.2.20
On completion of enhancement
works in Sectors 1 and 2, works can commence on construction of the Created
Marsh Habitat and formation of the residential area. It is proposed to
coordinate these ativities to minimise use of heavy machinery on the site. Once
the main structure of the marsh is formed, works can commence on Sector 3.
2.2.21
Following enhancement fishponds
will be managed under the modified regime outlined in the Habitat Creation and
Management Plan.
2.2.22
The major construction works
involved in pond enhancement relate to the removal of bunds between adjoining
ponds. To minimise disturbance to the rest of the site it is proposed that
enhancement works are conducted on one pair of ponds at a time.
2.2.23
Figure 2‑11 illustrates the location of new bunds. Further
details are discussed in the Habitat Creation and Management Plan (Section 14).
Interim Management
2.2.24
To compensate for disturbance
associated with the construction of the residential development and the WNR, it
is proposed that ponds in Sectors 1, 2 and 3 will be managed according to an
interim management regime that is intended to enhance their short-term value
for Species of Conservation Importance, particularly wetland birds. Enhancement
will be achieved through the following specific actions which have yielded
demonstrated improvements to the value of fishponds for wetland birds when
implemented elsewhere in Hong Kong:
·
The fish populations within
ponds will vary greatly depending on previous management. A rapid assessment of
remaining populations will be carried out and ponds re-stocked, as required,
with trash fish species;
·
Initial and ongoing correction
of water quality, specifically pH to ensure appropriate conditions for fish
survival. Although trash fish species are relatively hardy compared to many
commercial fish, they can be affected by low pH conditions. If pH drops below
4.5 then peanut residue will be added to raise pH; and,
·
Rotational, partial drain down
of pairs ponds. Once drained down each pair of ponds will be maintained with
shallow water < 30 cm deep
for a period of 4weeks.
Long-term Management
2.2.25
Once all construction works are
completed, the WNR will be managed according to a long-term management plan
following guidelines described within the Habitat Creation and Management Plan
for the site.
Table 2‑2 Habitat Enhancement
Work Programme For The Fung Lok Wai WNR
|
Construction Phase
|
Period
|
Construction activities
|
|
Pre-construction Phase I
|
Jul 2010
|
Site handover
All ponds under existing management
|
|
Pre-construction Phase II
|
Oct 2010 – Mar 2011
|
Enhance Sector 1 ponds
All other ponds remain under existing management regime
|
|
Pre-construction Phase III
|
Apr – Sep 2011
|
Commence site clearance of Residential Development area and Marsh
area
Enhance Sector 2 ponds
Interim management of Sector 1 ponds.
Sector 3 and marsh area ponds remain under existing management regime
|
|
Pre-construction Phase IV
|
Oct 2011 – Mar 2012
|
Continue site clearance and forming of Residential Development area
Commence Marsh Creation works
Interim management of Sector 1, 2 and 3 ponds
|
|
Pre-construction Phase V
|
Apr – Sep 2012
|
Continue site clearance and forming of Residential Development area
Complete Marsh Creation works and commence establishment
Enhance Sector 3 ponds
Interim management of Sector 1 and 2
|
|
Pre-construction Phase VI
|
Oct 2012 – Jun 2013
|
Continue site clearance and forming of Residential Development area
Establishment of Marsh habitats
Interim management of Sector 1, 2 and 3 ponds
|
|
Construction Phase
|
Jul 2013 – Sep 2016
|
Residential Development construction
Management of Marsh habitat
Interim management of Sector 1, 2 and 3 ponds
|
|
Operation Phase
|
Oct 2016 onwards
|
Occupation of Residential Development
Long-term management of the WNR
|
Improvement works of Access Road Leading
to the Subject Site
2.2.26
Based on a preliminary MLP, the
existing Fuk Shun Street
will be used as the proposed access road of the proposed residential
development and the WNR.
2.2.27
Fuk Shun Street
roots from the southern side of the Site and terminates at Fuk Hi Street at northern side of Yuen
Long Industrial Estate. It is currently a local road of various widths ranging
between 6m to 7m. It is the principal access of Ng Uk Tsuen
and other scattered developments along the road.
2.2.28
As Fuk Shun Street is currently
a substandard road, the project proponent is proposed to upgrade it to a 7.3m wide single 2-lane road with standard 2m wide footpath provided on both sides of
the road (see Figure
2‑8).
2.2.29
Improvement works at Fuk Shun Street is
planned to be completed in the 3rd quarter of 2016 prior to the
occupation of the Project.
2.2.30
Various construction activities
of the improvement of access road include site clearance and formation, laying
of drainage, sewerage and utilities, formation of road sub-base, levelling and
compaction, road paving and installation of road furniture.
Construction Works for the Residential
Development
2.2.31
The Subject site is currently
occupied by a total of 56 fishponds, which are fed by rainwater. Overflowing to
the nearby rivers occurs in heavy rainstorms. Figure
2‑9 presents a pond numbering system used throughout in
the EIA before the construction of the WNR.
2.2.32
The residential portion of the
Project will be located at the southwestern edge of the Subject Site and
occupies around 5% of the entire site (approximately 4ha). A total of 5 existing bunded ponds No. 19, 23,
25, 59 and 62 will be affected.
2.2.33
All the bunds situated within
the residential site will be demolished during site clearance. In order to
minimise the generation of solid waste, the demolished materials from the bunds
will be temporarily stored on-site and re-used as filling materials for the
Project.
2.2.34
After the clearance of bunds,
the affected ponds will be dredged, and filled, with fill materials spreaded
over the site and compacted to form the residential area. These works will be
completed prior to the commencement of foundation and superstructure works.
2.2.35
To the extent possible, pond
draining and dredging will be planned during the dry seasons when water levels
of the fishponds are relatively lower and the substrate will not be too soft.
2.2.36
During ponds draining, the
opportunities to retain the existing pond water for reuse will be maximized
through re-distribution of the pond water at the worksite to other existing
ponds as far as practicable so as to avoid discharging them to the nearby river
channel.
2.2.37
Excavators used in common civil
works will be employed for pond dredging. From the experience of the
development at Tin Shui Wai, the amount of topsoil required to be dredged is
estimated to be about 0.3m
deep i.e. 12,300m3 of
dredged materials will be generated. The dredged substrate will also be
temporarily stored and reused on-site for the establishment of the WNR. It is anticipated that there will be no
surplus dredged materials to be disposed of. If there is any, the dredged pond
sediment which is usually not allowed to be disposed of at landfills and also
may not be accepted by the public fill area because of its high organic
content, will adopt marine disposa1. It is understood that before any disposal,
a full set of parameters as required under ETWB TCW No.34/2002 will be
tested to determine the disposal options.
2.2.38
Spreading and compaction of
fill material will be performed at the residential area after pond filling. It
is envisaged that fill materials such as marine sand or recycled C&D
materials would be used for pond filling at residential area and this would be
brought to site by dump trucks via the access road. The quantity of fill
materials required for the residential area is estimated to be in the range of 94,300 m3.
2.2.39
Bored piling will be employed
for foundation works for the residential buildings. The internal roads,
drainage and utilities can be constructed under the respective development
packages. The residential blocks will be constructed on suspended slab to
address settlement problem while the pavement can be constructed on slab at
grade. For using bored piling, it is estimated that some 180 numbers of 2.5m diameter bored piles will be required.
2.2.40
Furthermore, a small sewage
pumping facilities and associated sewers will be constructed within the
development to divert the sewage to public sewers leading to existing public
sewerage network for ultimate treatment at Government sewage treatment works.
The sewage will be domestic in nature and no industrial wastewater will be
generated.
2.2.41
All the associated sewers
within the residential development will be built beneath the building areas.
Further details of the sewage pump house and sewers are presented in Section 8 -
Sewerage and Sewage Treatment Implications.
2.3.1
According to the EIA study of
“Yuen Long and Kam Tin Sewerage and Sewage Disposal Stage 2” (EIA-094/2004) approved on 17 June 2004,
there are two schemes proposed – Conforming Scheme of 2A-1T and Alternative scheme of 2A-1. Two of the Designated Projects (DPs)
identified in the project are Package 2A-1T
and its alternative, which are the construction of the Yuen Long Sewerage
Treatment Works (YLSTW) Effluent Pipeline. They will be close to the Project as
they include the construction of pumping station to the north of YLSTW and twin
rising mains. In particular the twin rising mains of Package 2A-1T will be laid from YLSTW to Tin Tsz Road in Tin
Shui Wai via the southern boundary of the Project. EIA-094/2004 concluded that
the Alternative scheme of 2A-1T
which was further away from the Fung Lok Wai Project was the preferred option.
However, the proposed sewerage project is now classified as a Category B
project under the Public Works Programme. It is our understanding that Drainage
Services Department (DSD) is preparing to conduct the feasibility study. The final alignment and construction schedule of the sewerage works as discussed in the approved EIA report is not
confirmed. After carrying out and
confirmation of the feasibility study, DSD will initiate the detail design
process and get funding approval from the Legislative Council. It is estimated that DSD will need years to
complete the study, design and approval process. Therefore, no construction
programme is available at the present stage for the proposed sewerage
work. On the other hand, construction
work for the proposed residential development at the Subject Site is scheduled
to complete by 2016. Since
there is no anticipated overlapping of construction works between the two
projects, hence cumulative dust impact assessment is considered not necessary.
2.3.2
The construction of Hong Kong
Wetland Park (HKWP) has been completed and is considered to have no cumulative
impact on the construction work of the Project.
2.3.3
The HKWP is located to the east
of the Project site. Mitigation measures
as presented in Section 4.4 and Section 5.6 to 5.7 are proposed to minimize the
potential air and noise impacts on nearby ASR and NSR, including the HKWP. In
addition, the water bodies of the HKWP and the Project are not inter-connected.
Given no significant amount of water will be discharged to the surrounding
water bodies by the Project during the construction and operational phase and
all domestic sewers of the Project would be diverted to the public sewerage
system. It is thus considered that no unacceptable impacts would be imposed on
the HKWP by the Project during both the construction and operational phase. Further
details on water quality impact and sewerage implications are discussed in
Section 6 and Section 8 respectively.
2.3.4
The possible concurrent
projects in the vicinity of the subject site are illustrated in Figure 2‑12.
3.1
Background
3.1.1
The Site has a long planning
history dating back to 1980’s. The initial development proposal was to
develop the site for low density residential houses and a golf course.
3.1.2
Realizing the ecological importance
of the Site to wildlife, in particular to birds, the land owner subsequently
made various applications to the Town Planning Board for the permission of a
development comprising low density houses on about half of the site and a
nature reserve on the remaining half in the early 1990’s. These
applications were all rejected by the Board.
3.1.3
The development proposal then
further evolved to be more sympathetic to the ecological value of the
Site. A revised development scheme
comprising apartments development on a development footprint of only 5% (i.e. 40,000m²) of the Site with
plot ratio of 0.185 plus a 76 Ha
(95% of the Site) Wetland Nature Reserve was proposed to the Town Planning
Board in 1999. This proposal was
accepted by the Board. As a consequence,
the Site was rezoned to “Other Specified Uses – Comprehensive Development and
Wetland Enhancement Area” with a maximum gross floor area of 148,000m² in 1999.
3.1.4
As presented in the Project
Profile (No. PP-091/2000), the preliminary MLP has a footprint area for the
residential development at the southwestern corner of the Subject Site with an
access road to the west. The approximate size of this footprint for the
residential area is 4 ha. The
original preliminary layout of the Project is illustrated in Figure 3‑1.
3.1.5
In accordance with the
requirements of the EIA Study Brief (ESB-055/2000) issued by EPD under the
terms of the EIAO in 2000, ecological investigations were undertaken at Fung
Lok Wai including a 12-month flora and fauna survey between January and
December 2001.
3.2.1
Analysis of the baseline data
obtained from the ecological surveys indicated three constraints on the
proposed development:
·
The location of the egretry
(present at the time of ecological survey but is now abandoned) in the southern
part of the assessment area could result in flight line interference of birds
attempting to access food resources within Fung Lok Wai;
·
Accessing the site from the
west adjacent to the Hong Kong Wetland Park, as originally proposed, will
require additional construction work and may potentially cause disturbance to
the egretry; and
·
It is desirable to maintain
linkages between all the wetland habitats within the Fung Lok Wai assessment
area, including the mosaic of wetlands in the southern part of the Assessment
Area.
3.3.1
To minimize the potential
direct and indirect impacts of the residential development on the habitats and
species populations of Fung Lok Wai, a range of development options have been
examined and several modifications are made to the development proposal (Figure 3‑2) including:
·
Shifting of residential
development area;
·
Alternative route for
development access; and
·
Establishment of a potential
alternative egretry within the proposed Wetland Nature Reserve.
3.4.1
A four-season ecological survey
and flight path study was conducted to investigate the impacts of the presence
of buildings on the bird flight path in January 2001. Details of the survey
including the methodology and findings are presented in Section 13 Ecological
Impact Assessment.
3.4.2
During the survey, a newly
formed egretry was identified in April 2001 to the southwest of the subject
site located within the Fung Shui Woodland at Shing Uk Tsuen. Initial analysis
of the original proposed location of the residential development area indicated
the potential for interference with the flightlines of herons and egrets moving
to and from the egretry. The flight path
patterns showed that most flights occur at low altitudes and are equally
affected by low or high rise buildings and location of the buildings is more
important than building height in respect of obstruction to flight path.
3.4.3
Consequently, various options
were considered to investigate the impacts of the location of the development
footprint. It was found that while
shifting the development footprint eastwards, obstruction to bird flight path
would decrease. However, with the
development footprint moves more and more towards the centre position along the
southern boundary, it will result in more disturbance impacts to the proposed
Wetland Nature Reserve.
3.4.4
Balancing the above said
factors, it was decided that the proposed development area be moved
approximately 150m
eastwards of its original position (i.e. about 200m away from the egretry). This will dramatically reduce potential
interference with flight lines associated with the egretry and will provide an
additional benefit of retaining the linkage between the Fung Lok Wai wetlands
and the adjacent wetlands lying to the south and southwest of the site.
3.5.1
Two alignments for the access
road to the Project are considered, namely the Western Development Access
(which is the access proposed in the Project Profile) and the Southern
Development Access (which is an existing access from Fuk Shun Street).
The Western Development Access
3.5.2
The Western Development Access
follows an existing village track from the west along the southern boundary of
the Hong Kong Wetland Park. This road will connect the western boundary
of the subject site to Junction P (Tin
Wah Road/Wetland Park Road/Tin Tsz Road) in Tin
Shui Wai.
Engineering Concerns
3.5.3
It is proposed that the
existing village track will be upgraded and widened to a 6.75m wide single carriageway with one-sided
footpath (1.6m
wide).
Land Status
3.5.4
The proposed access road will
be entirely on government land albeit a portion of the road (about 4,543 m²) will encroach into
the Hong Kong Wetland Park
boundary.
Air and Noise Impacts
3.5.5
A few village huts are found
locating near the Western Development Access. They will be mostly affected if
the Western Development Access is adopted.
Ecological Impact
3.5.6
The footprint of the access
road comprises six habitats namely intertidal forested wetlands (8 m²), permanent stream (6 m²), grassland (2,004 m²), aquaculture pond
bund (460 m²),
wasteland (2,291 m²) and
works-in-progress (2,047 m²).
3.5.7
Apart from the intertidal
forested wetlands (8 m²)
and the permanent stream (6 m²)
which are of high and moderate ecological value respectively, all other
habitats affected by the road are of low ecological value.
3.5.8
Although there are potential
disturbance generated during construction and operation of the access road to
wetland birds which roost and forage within the intertidal forested wetlands
present along the southern boundary of the Hong Kong Wetland
Park, these impacts can
be satisfactorily mitigated.
3.5.9
Possible impacts may occur on
the flight lines of Ardeids from the Shing Uk Tsuen egretry across the access
road to the Hong Kong
Wetland Park
and the Wetland Nature Reserve.
Landscape and Visual Impact
3.5.10
The Western Development Access
would skirt the fishpond area to the north of the development site leading to
landscape and visual disturbance of the existing fishponds.
3.5.11
The footprint of the proposed
Western Development Access would lead to the additional loss of landscape
resources namely wetlands (8 m²),
watercourses (6 m²) and
grassland (2,004 m²).
The proposals would also lead to the loss of approximately 100m length of scrub on the existing pond
bund along the south western boundary of the proposed WNR. This area acts as a
landscape buffer between the existing intact fishpond areas which form the
large part of the proposed WNR and the abandoned fishpond area to the south
west.
The Southern Development Access
3.5.12
The Southern Development Access
is via an existing village road Fuk
Shun Street connecting the subject site with Yuen
Long Industrial Estate.
Engineering Concerns
3.5.13
Fuk Shun Street
is currently a surfaced substandard road.
In order to use it as development access, it would be necessary to widen
it to about 7.3 m wide
single 2-lane road with 2 m
wide footpath provided on both sides of the road.
Land Status
3.5.14
The road widening works will
involve government land only. However,
it will be subject to government’s assistance in the clearance of any licence,
short-term tenancy or unauthorised occupation along the existing roadside.
Air and Noise Impacts
3.5.15
A number of low-rise village
houses are built along both sides of Fuk
Shun Street.
However, with the mitigation measures proposed in Chapters 4 and 5 in place, the air and noise impacts can be
satisfactorily mitigated.
Ecological Impacts
3.5.16
As the Southern Development
Access is already a surfaced road in operation running through Yuen Long
Industrial Estate, the use of this road for access will have no ecological
impact.
Landscape and Visual Impact
3.5.17
The Southern Development Access
would involve the widening of the existing Fuk Shun Street through Tai Tseng Wai
within the existing land take and so would not lead to any significant further
loss of landscape resources within the Study Area. Beyond the short term
construction phase impacts relating to the disturbance of the existing
landscape the operational phase would not lead to any degradation of the
landscape character of the existing road corridor or the visual amenity
available to the residents of the adjacent village houses.
3.5.18
The table below compares the
two access options:
Table 3‑1 Comparison of the Two Access Options
|
|
Western access
|
Southern access
|
|
Engineering concerns
|
Upgrading
an existing village track to 6.75m
wide with one-sided footpath (1.6m
wide)
|
Widening
an existing substandard surfaced access to about 7.3m wide single 2-lane road with 2m wide footpath on both sides of the road
|
|
Land Status
|
-Entirely
on government land
A portion
of the road (about 4,543m²)
will encroach into the Hong
Kong Wetland Park boundary
|
Entirely
on government land, however, government’s assistance in the clearance of any
licence, short term tenancy or unauthorised occupation if any along the
existing roadside is required
|
|
Air & noise impacts
|
A few
village huts near the access will be affected by the road
|
Some
village houses near the access will be affected. However with the proposed mitigation
measures in place, impacts can be mitigated satisfactorily
|
|
Ecological impact
|
Impact on
a small area (8 m²)
of intertidal forested wetlands which is of high ecological value
Potential
disturbance to wetland birds roosting and foraging in the intertidal forested
wetlands within the Hong Kong
Wetland Park
and the Wetland Nature Reserve but can be satisfactorily mitigated
Possible
impacts may occur on the flight lines of Ardeids from the Shing Uk Tsuen
egretry across the access road to the Hong Kong Wetland
Park and the Wetland
Nature Reserve.
|
As the
Southern Development Access is already a surfaced road in operation running
through Yuen Long Industrial Estate, the use of this road for access will
have no ecological impact.
|
|
Landscape & visual
|
Landscape
and visual disturbance of the fishponds including the additional loss of
landscape resources.
|
Short-term
construction phase impacts relating to the disturbance of the existing road
landscape. The operational phase would not lead to any degradation of the
landscape character of the existing road corridor or the visual amenity
available to the residents of the adjacent village houses.
|
3.5.19
Taking into account the above
said factors and the shifting of the residential development to a more easterly
location, the Southern Development Access is considered to be more preferable
especially from ecological perspective.
3.6.1
During the four-season
ecological survey, an egretry on the southwest perimeter of the Assessment Area
was found established in April 2001. The flightlines of birds to and from this
egretry tended to track across the southwest corner of the study site,
particularly at low altitudes (<40m).
3.6.2
It was found that by shifting
the development footprint eastwards to 200m away from the egretry location, the obstruction
to the flightlines from the egretry to the Wetland Nature Reserve can be
substantially reduced and that a reasonable buffer is maintained between the
residential development and the egretry.
Furthermore, a further measure is proposed by creating a potential
alternative egretry of similar size (about 2,000 m²) and plant species within the Wetland Nature
Reserve. Although the egretry was
subsequently found abandoned, a potential alternative egretry is proposed in
the northeastern section of the Study Site, which will be subject to minimal
disturbance from both the construction, and operational stages of the
development.
3.7.1
In accordance with the
requirements of Clause 3.5.9.5(iv) under
the Landscape and Visual Impact section of the Study Brief, alternative
building heights of maximum 10-storey, 15-storey and 25-storey shall be
assessed to examine the visual compatibility with the surrounding rural
setting.
3.7.2
Three development options for
the residential portion are assessed: (Figure
3‑3a to c and Figure
3‑4)
·
Option 1A – all buildings not more than 18 storeys (8 blocks
of 14-18 storeys, 7 groups of low-rise buildings of 4-8 storeys including a
resident’s club house erected on 40,000m² residential site area i.e. 32.8% Site
Coverage);
·
Option 1B – all buildings not
more than 15 storeys (9 blocks of 15 storeys, 7 groups of low-rise buildings of
4-10 storey including a resident’s club house erected on 40,000m² residential site area
i.e. 34.4% Site Coverage); and
·
Option 1C – all buildings not more than 10 storeys (29 blocks
of 7-10 storeys, 27 4-storey terrace houses and a resident’s club house erected
on 60,000 m²
residential site area i.e. 34% Site Coverage).
3.7.3
Full details of the assessment
are presented in Section 11 Landscape and Visual Impact Assessment.
3.8.1
In respect of air quality
impact, noise impacts, water quality impacts, sewerage and sewage treatment
implications, waste management implications, fisheries impact and cultural
heritage impact, , the impacts on the three development scenarios, namely
Option 1A, Option 1B and Option 1C are considered similar and acceptable.
However, the three options will differ in the aspects of ecological impact and
landscape and visual impact. The
following table sets out the comparison:
|
|
Option 1A
|
Option 1B
|
Option 1C
|
|
Development parameters
|
|
Residential Development Site Area
|
4 Ha
|
4 Ha
|
6 Ha
|
|
GFA
|
148,000 m²
|
148,000 m²
|
148,000 m²
|
|
Building height
|
Medium-rise
blocks: 14 to 18 storeys
Low-rise
blocks: 4 to 8 storeys
Club house: 2
storeys
|
Medium-rise
blocks: 15 storeys
Low-rise
blocks: 4 to 10 storeys including
club house
|
Low-rise
blocks: 7 to 10 storeys
Terraced
houses: 4 storeys
Club house: 2
storeys
|
|
No. of blocks
|
Medium-rise
blocks: 8
Low-rise blocks:
6
Club house: 1
|
Medium-rise
blocks: 9
Low-rise blocks:
7 including club house
|
Low-rise blocks:
29
Terraced houses:
27
Club house: 1
|
|
Building site
coverage on Residential Development Site Area
|
About 32.8% of 4 Ha site area
|
About 34.4% of 4 Ha site area
|
About 34% of 6 Ha site area
|
|
Site area of the
Wetland Nature Reserve
|
76 Ha
|
76 Ha
|
74 Ha
|
|
Compliance with planning intention of
“OU(CDWEA)” zone under Outline Zoning Plan
|
|
Compliance with
“No net loss in wetland” principle
|
Yes
|
Yes
|
No
|
|
Ecological Impacts
|
|
Habitat loss
|
No net loss of
wetland area achievable through pond enlargement and marsh habitat creation
|
No net loss of
wetland area achievable through pond enlargement and marsh habitat creation
|
Net loss of
wetland area will arise
|
|
Habitat
fragmentation
|
Fragmentation
will be low due to relatively small footprint and maintenance of sight lines
for birds
|
Fragmentation
will be slightly greater than Option 1A as there will be
less visibility for birds due to greater number of buildings – more
obstruction of sightlines
|
Fragmentation
will be greater than Options 1A
and 1B as there will be less visibility for birds due to greater number of
buildings – more obstruction of sightlines. The larger footprint will also
reduce connectivity between fish pond habitats and wetland mosaic habitats
|
|
Disturbance
|
Predicted
disturbance of sensitive species, particularly birds, during construction and
operation can be fully mitigated through interim and long-term management of
the WNR
|
Predicted
disturbance of sensitive species, particularly birds, during construction and
operation can be fully mitigated through interim and long-term management of
the WNR
|
Disturbance
effects greater than Options 1A
and 1B (due to large development area) and area for compensation (WNR area)
will be less. It is less likely, therefore, that disturbance effects can be
fully mitigated
|
|
Pollution
|
No significant
pollution effects predicted
|
No significant
pollution effects predicted
|
No significant
pollution effects predicted
|
|
Soil compaction
|
No significant
soil compaction effects predicted
|
No significant
soil compaction effects predicted
|
No significant
soil compaction effects predicted
|
|
Hydrological
disruption
|
No significant
hydrological disruption predicted
|
No significant
hydrological disruption predicted
|
No significant
hydrological disruption predicted
|
|
Landscape
and Visual Impacts
|
|
Landscape
Resources
|
Residential
development area is restricted to 4 Ha
to minimize the impact on landscape resources
|
Impacts on
landscape resource similar to those for Option 1A.
|
Larger impact on
landscape resource due to increased residential development area resulting in
greater loss in fishponds and larger extent of land formed area.
|
|
Landscape
Character
|
Residential
development area is restricted to 4 Ha
to minimize the impact on the existing landscape character
|
Impacts of Option
1B on the existing landscape character of the area similar to those for
Option 1A due to the shared
characteristics of the two schemes.
|
The larger
residential development area leading to the truncation of the fishponds from
the wooded hill sides which form their settings, the loss of area and the
indirect impacts on the character of the remaining fishponds will be greater
than in Option 1A
& Option 1B
|
|
Visual Impacts
|
The developments
adopts a medium-rise form utilising a stepped building profile (14-18
storeys) in response to the existing landform and maximises visual
permeability through the creation of view corridors and sky gardens allowing
visual access to the hillsides beyond through the locations of the low-rise
buildings between the proposed medium-rise blocks. This development profile
will minimize the visual impacts experienced by nearby VSRs. The slightly
taller buildings in Option 1A
(14-18 storeys) will have a slightly greater impact on the VSRs immediately
adjacent to the proposed development including the residents on the northern
periphery of Ng Uk Tsuen and Shing UK Tsuen than in Option 1B which is lower
in height at 15 storeys
|
The medium-rise
form of Option 1B (15 storeys) incorporates blocks of equal height (15
storeys) and will not incorporate the stepped building height profile.
Although the constant height for the individual blocks will not create the
same dynamic relationship in terms of the building form with the existing
landscape context which exists with Option 1A, the slightly lower buildings than in Option 1A has improved the impact on the VSRs
immediately adjacent to the proposed development. Similar to Option 1A the creation of a permeable and responsive
building form preserves, as far as possible, the visual relationship between
the existing estuarine landscape and its setting of wooded hillsides.
|
Option 1C comprises buildings of 7-10 storeys
aligning along the southwest portion of the site and 4-storey terraced houses
fronting onto the WNR. Although when
viewed from a distance, this development form is more akin to the traditional
vernacular village architecture of the region in terms of its form, the development
does not respond to the visual dynamics of the existing landscape context
especially when viewed from the north the development visually coalesces to
form a wall with no visual access to the landscape beyond.
|
3.8.2
Only Option 1A and Option 1B can comply with the planning
intention of “OU(CDWEA)” zone for the principle of “no net loss in wetland” as
stipulated in Outline Zoning Plan No. S/YL-LFS/7.
3.8.3
In respect of ecological
impacts Option 1C will
result in a net loss of wetland area. It has the largest development site area
which will result in greater level of disturbance to the WNR. Under Option 1C the WNR will be correspondingly
smaller reducing the area available for wetland compensation. On this basis the
potential ecological impacts arising from Option 1C are considerably greater than those arising from
Options 1A and 1B.
3.8.4
The ecological impacts of
Options 1A and 1B are similar in
many respects and are considered acceptable.
The only slight difference between these two options arising from the
larger number of buildings in Option 1B. The gaps between buildings will be
smaller in this option creating a slightly greater blockage of sightlines for
birds. It is predicted, therefore, that Option 1B will result in slightly
greater habitat fragmentation than Option 1A.
On this basis there is a preference for Option 1A over 1B on ecological grounds.
3.8.5
The findings of the assessment
suggest that Options 1A and
1B are more acceptable than
Option 1C from a landscape and visual perspective due to responsive building
heights, incorporation of view corridors and their smaller development site
area. This allows both schemes to be better integrated into the landscape and
visual context while maintaining the relationship between the upland and the
flat expanse of the coastal plane. While both Options 1A and 1B are acceptable from landscape and visual
impact point of view, Option 1B is slight better than Option 1A in respect of the slightly lower
buildings which will improve the impact on the VSRs immediately adjacent to the
proposed development. Whereas Option 1C
which although having slightly lower building height would create wall like
affect due to the number of buildings required, the consistent building heights
and the lack of space available for the creation of view corridors. In addition
the more extensive development site area would lead to an additional loss of
landscape resources and create barrier between the fishponds and their upland
setting.
3.9
The Preferred Development Option
3.9.1
In order to minimize the
potential impacts of the residential development on the habitats within the
Study Area, the proposed residential development area has been shifted
eastwards to 200m
from the (now abandoned) egretry at Shing Uk Tsuen and the Southern Development
Access is adopted. Figure 3-5 shows the original
location and the shifted location of the proposed residential development. The development options with development area of 4 ha (i.e. Option 1A and 1B) are the preferred scenarios from both
ecological impact and landscape and visual impact perspectives.
3.9.2
Option 1C will result in a net loss of wetland area and is
therefore eliminated from further study.
The development options with development area of 4 ha (i.e. Option 1A
and 1B), which will result in no net loss in waterbody area, are similar in
many respects such as air quality impact, noise impacts, water quality impacts,
sewerage and sewage treatment implications, waste management implications,
fisheries impact and cultural heritage impact. However, in respect of ecological
impacts Option 1A is
slightly superior to option 1B whereas in respect of landscape and visual
impacts Option 1B is considered slightly superior to Option 1A.
In general terms though these differences are slight and the
environmental impacts of both Options 1A
and 1B are found to be acceptable and are therefore taken as the preferred
scenarios for this environmental impact assessment exercise.
4.1.1
This section presents an air
quality impact assessment for the construction of the Project in accordance
with Clause 3.5.1 of the Study Brief. Fugitive
dust emissions from construction activities are considered a key issue and are hence
addressed here. Air quality impact during the operational phase of the Project
is expected to be insignificant and is not required in the Study Brief.
4.1.2
This section addresses the
potential air quality impact associated with the construction of the proposed
residential development, the associated access road and the Wetland Nature
Reserve at Fung Lok Wai. Air sensitive receivers (ASRs) have been identified in
the vicinity of the Project with representative ones selected for this
assessment to predict quantitatively the possible worst-case impact.
4.1.3
The assessment covers an area
of 500m from the
Project site boundary (including the Southern Development Access) in accordance
with the requirements of the EIA Study Brief. (Appendix 1-1 refers).
4.2.1
The principal legislation
regulating air quality in Hong Kong is the Air
Pollution Control Ordinance (APCO) (Cap. 311).
Air Quality Objectives (AQOs) are set for the whole territory, which
specify the statutory limits for various criteria pollutants and the maximum
numbers of times of exceedance allowed over a specified period of time. The AQOs for Carbon Monoxide (CO), Nitrogen
Dioxide (NO2), Sulphur Dioxide (SO2), Total Suspended Particulates (TSP) and
Respirable Suspended Particulates (RSP), which are relevant to this assessment,
are summarised in Table 4‑1 below.
Table 4‑1 Hong Kong Air Quality Objectives
|
Pollutant
|
Pollutants
Concentration (μg/m3)
|
|
Averaging Time
|
|
1 hour (i)
|
8 hours (ii)
|
24 hours (ii)
|
1 year (iii)
|
|
CO
|
30,000
|
10,000
|
N.A.
|
N.A.
|
|
NO2
|
300
|
N.A.
|
150
|
80
|
|
SO2
|
800
|
N.A.
|
350
|
80
|
|
TSP
|
N.A.
|
N.A.
|
260
|
80
|
|
RSP
|
N.A.
|
N.A.
|
180
|
55
|
(i) Not to be exceeded
more than 3 times per year;
(ii) Not to be exceeded
more than once per year;
(iii) Arithmetic means;
N.B. Concentrations measured
at 298 K and 101.325 kPa (one atmospheric pressure).
4.2.2
In addition to the AQOs, EPD
requires under Annex 4 in the
Technical Memorandum on EIA Process issued under the EIA Ordinance an hourly
TSP limit of 500mg/m3 for
construction dust impact assessment.
4.2.3
It is noted that the Air
Pollution Control (Construction Dust) Regulation came into effect since 16 June
1997. Site formation, construction of
the foundation and superstructure of buildings, road construction works, etc.
are classified as “notifiable work” under the Regulation. Any works which involve stockpiling of dusty
materials, loading, unloading or transfer of dusty materials, transfer of dusty
materials using a belt conveyor system, use of vehicles, debris handling,
excavation or earth moving, site clearance, etc. are regarded as “regulatory
work”.
4.2.4
A Schedule specifying the dust
control requirements for a variety of construction activities is included in
the Regulation. Contractors responsible for a construction site where a
notifiable work and/ or regulatory work is involved have to ensure that the
work is carried out in accordance with the Schedule with regard to dust
control.
4.3.1
Quantitative air quality impact
study requires the consideration of background air quality for presentation of
the cumulative impact. The ambient air quality in the assessment area has been
assumed to be same as the annual average of air pollutant concentrations of
NO2, RSP, TSP and SO2 measured at EPD’s Air Quality Monitoring Station in Yuen
Long.
4.3.2
Average values for each
pollutant in year 2002 to 2006 were obtained and summarised below in Table 4‑2
Table
4‑2 Annual Average
Concentrations of NO2 and RSP measured at EPD’s Air Quality
Monitoring Station in Yuen Long from 2002 to 2006
|
Air Pollutant
|
Concentration (mg/m3)
|
|
NO2
|
60
|
|
TSP
|
100
|
|
RSP
|
62
|
|
SO2
|
24
|
4.4.1
The construction of the Project
is scheduled to commence in the 3rd quarter of 2010 and will be
completed by the 3rd quarter of 2016. Various construction activities include site
clearance and formation for construction of access road and the residential
portion of the Project, ponds draining, dredging and filling, foundation and
superstructure works, roadworks, construction of sewerage facilities, and
establishment of the Wetland Nature Reserve, etc. No concrete batching plants
and crushers would be necessary for the works. In addition, blasting would not
be required.
Major Sources of Air Quality Impact
4.4.2
Major sources of air quality
impact during the construction phase would be fugitive dust emissions.
Emissions of other air pollutants such as carbon monoxide and dioxide, nitrogen
oxides and sulphur dioxide generated by powered mechanical equipment and
vehicle exhausts on-site should not be significant, considering their limited
number and percentage on-time on-site.
4.4.3
There will also be emissions
from diesel trucks used in haulage of materials. As there will only be limited number of
trucks concurrently on-site, impact on the air quality is not considered
significant.
4.4.4
Other major sources of dust
emissions could be attributed to the following activities: -
·
Unloading of fill materials
from dump trucks for pond filling;
·
Vehicle movements on unpaved
haul roads;
·
Wind erosion on exposed ground
and stockpiling areas; and
·
Handling of excavated material
and construction debris.
4.4.5
The residential portion of the
Project will occupy an area of approximately 4
ha. It is envisaged that the total amount of topsoil that could
be dredged (~12,300m3)
from the residential portion can be retained and transferred within the site as
fill material for the establishment of the WNR during the 4th quarter of 2011 to 1st
quarter of 2012. Given that the materials are mainly derived from fishponds with
high moisture content and dredging works will be carried out at a few fish
ponds each time, fugitive dust emission is not considered a problem during
ponds dredging, re-profiling of pond bunds and partial filling of ponds at the
WNR.
4.4.6
As the access road of the
Development will rely on existing paved Fuk Shun Street, the limited site
clearance works and junction improvement works to widen the road will be
constructed in 50m section
by section. The volumes of excavated spoil are expected to be low. The number of vehicle trips during construction
is expected to be very small and vehicle movements will be on existing paved
roadways. The construction works for access road is anticipated to cause
insignificant dust emission impacts when the construction mitigation measures
as recommended in Section 4.4.25 are implemented and through the Environmental
Monitoring & Audit programme.
4.4.7
The sewers will be constructed
in 50m section by section. With
such small scale of construction works, the potential dust impact would be
limited and short term in nature. The volumes of excavated spoil are expected
to be low. The number of vehicle trips during construction is expected to be
very small and for most areas, vehicle movements will be on paved roadways.
Only minimal movement of vehicles on unpaved roads is anticipated. Subject to
government’s approval on the sewer alignment along Fuk Shun Street, the sewers will be
constructed together with the improvement works on Fuk Shun Street.
4.4.8
Particulate emission rates of
the dust emitting activities given in Section Error! Reference source not found.
were based on typical values and emission factors documented in Compilation of
Air Pollutant Emission Factors (AP-42) 5th Edition published by USEPA. Dust
emission sources resulting from material handling and excavation have been
modelled as point sources. Dust generation from traffic movement on unpaved
site roads have been modelled as line sources. Detailed calculation of emission
factors are given in Appendix 4-1.
Evaluation of Dust Impacts
4.4.9
Critical periods of fugitive
dust emissions will be during land formation for the marshland (i.e. between
4th quarter of 2011 and 1st quarter of 2012) and site formation for the residential
portion of the Project when fill material have to be imported and handled for
ponds filling, spreading and compaction (i.e. between 2nd quarter of
2012 and 1st quarter of 2013). For the prediction of the worst-case dust
impact, all the major activities in each of the 2 stages described in Section 4.4.15 below have been modelled and are assumed to be in
concurrent operation.
4.4.10
The fill materials imported for
land formation of marshland will be in composition similar to pond mud while
the fill materials imported for site formation of residential portion are
anticipated to be marine sand and recycled C&D materials. Both of those
imported materials are in relative high moisture content. Thus the dust
emissions modelled are anticipated to be in conservative estimation.
4.4.11
As the topsoil beneath the
ponds are of high moisture content and dredging works will be carried out at a
few fish ponds each time, dust emission is not considered a problem during pond
dredging at residential portion, and re-profiling of pond bunds, partial
filling of ponds during the establishment of WNR if mitigation measures are
properly implemented.
Air Sensitive Receivers
4.4.12
Existing and planned
residential developments at Tin Shui Wai are more than 500m away from the Project, only those
existing village huts scattered around the Project, mostly at the southern side
of the Site, are identified as Air Sensitive Receivers (ASRs). Worst affected
representative points were selected for the assessment. The locations of these
representative ASRs are shown in Figure
4‑1 and are described in Table 4‑3.
4.4.13
These representative ASRs are
all situated close to the Project. Should the dust impact on these worst
affected representative ASRs be mitigated to an acceptable level, dust impact
on other ASRs on the assessment area should also be mitigated satisfactorily.
4.4.14
Particulate levels were
predicted at the representative ASRs at 1.5m and 4.5m
and 7.5m above
ground for the 3–storeys village huts.
Table 4‑3 Representative
ASRs for the Dust Emission Impact Assessment
|
ASR
Label
|
Type
of ASRs
|
No.
of Storeys
|
Distance
from boundary of FLW Site
|
Assessment
Point (metres above ground)
|
|
A1
|
Village House (Man
Wa Garden)
|
3
|
32 m
|
1.5, 4.5, 7.5
|
|
A2
|
Village House
|
3
|
104 m
|
1.5, 4.5, 7.5
|
|
A3
|
Village House
|
3
|
124 m
|
1.5, 4.5, 7.5
|
|
A4
|
Village House
|
3
|
127 m
|
1.5, 4.5, 7.5
|
|
A5
|
Village House (Tin Hau Temple)
|
1
|
126 m
|
1.5
|
|
A6
|
Village House (Ng Uk Tsuen)
|
1
|
214 m
|
1.5
|
|
A7
|
Village House
|
1
|
15 m
|
1.5
|
|
A8
|
Village House
|
1
|
33 m
|
1.5
|
|
A9
|
Village House
|
1
|
22 m
|
1.5
|
|
A10
|
Village House
|
1
|
249 m
|
1.5
|
|
A11
|
Village House
|
1
|
32 m
|
1.5
|
|
A12
|
Village House
|
1
|
9 m
|
1.5
|
|
A13
|
Village House
|
1
|
9 m
|
1.5
|
|
A14
|
Village House
|
1
|
34 m
|
1.5
|
|
A15
|
Village House
|
1
|
27 m
|
1.5
|
Methodology
·
Stage A - land formation works
for the marshland area (4th quarter 2011 to 1st quarter 2012)
·
Stage B - Site formation works
for pond filling, spreading and compaction of fill materials at the residential
footprint (2nd quarter 2012 to 1st quarter 2013)
4.4.16
The air quality model “Fugitive
Dust Model” (FDM), which was specifically developed for the prediction of
fugitive dust emissions is well accepted by EPD and the USEPA for this purpose.
The model was developed based on the commonly accepted Gaussian dispersion
formulae for the estimation of pollutant concentrations but has been adapted to
incorporate a gradient-transfer deposition algorithm to account for the
settling of dust particles, and to include a wind dependent factor on dust
emission rates. The model is designed for fugitive dust impact prediction for
point, line, area and volume sources.
4.4.17
The following meteorological
data of year 2000 relevant to the study area have been obtained from Hong Kong
Observatory and used in the modelling of the dust emission dispersion:
·
Hourly wind direction and
speed, air temperature together with atmospheric Pasquill stability class at
Lau Fau Shan automatic weather station;
·
Daily morning and maximum
mixing heights based on the radiosonde ascent at King’s Park; and
·
Hourly total sky cover, cloud
amount and cloud based height of the 1st - 4th layers observed at the Hong Kong
Observatory Headquarters in Chek Lap Kok.
4.4.18
Based on particle size multiplier for the
unpaved road emission and the handling of excavated and construction materials
documented in the Compilation of Air Pollutant Emission
Factors (AP-42) 5th Edition published by USEPA, it was assumed
that 80% of particulates have size equal to 30µm, with the remaining 20%
assumed to be respirable with a size of 10µm.
An average dust density of 2500 kg/m3
was also assumed in the study.
4.4.19
The worst-case situations were
studied. Given the stringent noise
limits that need to be satisfied for construction works within the restricted
hours (1900 – 0700 the next day, Sunday and public holidays), it was assumed
that the working hours for construction activities is restricted to 0700 to
1900 hours only.
4.4.20
The alignment of haul roads,
locations of representative emission points of Stage A and Stage B are
presented in Figure
4‑2 and Figure
4‑3 respectively.
4.4.21
Maximum 1-hour average and
24-hour average TSP concentrations were predicted at the representative ASRs
and superimposed with the background TSP level of 100mg/m3
to compare with the 1-hour and daily TSP limits of 500mg/m3
and 260mg/m3
respectively to assess the acceptability.
4.4.22
Details of calculation of
particulate emission rates are presented in Appendix 4-1.
Modelled Results
4.4.23
The predicted highest 1-hour
average and daily average TSP concentrations at the representative ASRs at
various heights are shown in Table
4‑4. Appendix 4-2 presents a typical FDM result file for
reference. The TSP levels that exceed the relevant TSP criteria are shown in
bold.
4.4.24
The modelling results show that
under the hypothetical worst case situations when all major dust generating
operation are assumed to be in concurrent operation and under worst case
meteorological conditions, the unmitigated cumulative dust levels including all
the dust sources plus the background dust level will exceed the TSP criteria at
some ASRs.
Table 4‑4 Predicted Unmitigated TSP Level at selected ASRs
|
Representative ASRs
|
Predicted levels, µg/m3
(Stage A - unmitigated)
|
Predicted levels, µg/m3
(Stage B – unmitigated)
|
|
Location
|
ASR
|
mPD
|
1-hour TSP
|
24-hour TSP
|
1-hour TSP
|
24-hour TSP
|
|
Village House
(Man
Wa Garden)
|
A1
|
6.3
|
662
|
250
|
649
|
315
|
|
|
9.3
|
483
|
199
|
561
|
274
|
|
|
12.3
|
368
|
163
|
460
|
230
|
|
Village House
|
A2
|
12.2
|
356
|
156
|
309
|
186
|
|
|
15.2
|
298
|
146
|
262
|
169
|
|
|
18.2
|
262
|
139
|
219
|
154
|
|
Village House
|
A3
|
10.0
|
724
|
194
|
303
|
173
|
|
|
13.0
|
643
|
181
|
259
|
163
|
|
|
16.0
|
556
|
168
|
233
|
153
|
|
Village House
|
A4
|
9.6
|
364
|
169
|
430
|
155
|
|
|
12.6
|
331
|
158
|
356
|
146
|
|
|
15.6
|
278
|
141
|
284
|
136
|
|
Village House
(Tin Hau Temple)
|
A5
|
8.9
|
312
|
146
|
437
|
140
|
|
Village House
(Ng Uk
Tsuen)
|
A6
|
11.4
|
237
|
133
|
206
|
120
|
|
Village House
|
A7
|
5.6
|
242
|
127
|
191
|
116
|
|
Village House
|
A8
|
5.6
|
311
|
146
|
235
|
127
|
|
Village House
|
A9
|
5.3
|
630
|
305
|
165
|
123
|
|
Village House
|
A10
|
5.3
|
234
|
161
|
168
|
128
|
|
Village House
|
A11
|
5.6
|
192
|
118
|
156
|
110
|
|
Village House
|
A12
|
5.6
|
174
|
119
|
123
|
108
|
|
Village House
|
A13
|
5.6
|
144
|
112
|
131
|
107
|
|
Village House
|
A14
|
5.6
|
162
|
115
|
122
|
105
|
|
Village House
|
A15
|
5.6
|
180
|
121
|
151
|
112
|
Note:
1. A background TSP level of 100 mg/m3
has been included in the results.
2. Figures in Bold represent dust level
that can exceed the relevant standards.
Control/ Mitigation Measures for
Fugitive Dust Emission
General Site Management
4.4.26
Appropriate working methods
should be devised and arranged to minimise dust emissions and to ensure that
any installed air pollution control system and measures are operated and/or
implemented in accordance with their design merits. In the event of
malfunctioning of any control system or equipment, the relevant dusty
activities shall stop until the relevant control system or equipment are
restored to proper functioning.
4.4.27
Watering should be applied on
dusty areas and all dust emission sources twice daily. The frequency of
spraying required should be adjusted depending upon local meteorological
conditions such as rainfall, temperature, wind speed and humidity. The amount
of mist spraying should be just enough to dampen the material without over-watering,
which could result in unnecessary surface water runoff.
Vehicles and Site Haul Road
4.4.28
Dust emission from unpaved
roads comes predominantly from travelling of vehicles. Areas within the site
where there are regular vehicle movements should have an approved hard surface.
Speed controls at an upper limit of 10 kph will be imposed and their movements
should be confined to designed roadways within the site. All dusty vehicle
loads should have side and tail boards and should be covered by tarpaulin
extending at least 300 mm over
the edges of the side and tail boards.
Wheel-wash troughs and hoses should be provided at exit points of the
site.
4.4.29
The access road and the main
haul road (i.e. Haul Road
A in Figure
4‑2 and Figure
4‑3) at the entrance of the subject site have already
been paved currently.
Material Stockpiling and Handling
4.4.30
Fill materials required for
site formation works will be delivered regularly by dump trucks to the site and
for use in filling the ponds. Aiming to minimize the amount of stockpiling as
far as practicable, the trucks should maximize the opportunity to directly
unload the fill materials into the drained pond. The surface of the ponds under
filling and stockpile, if any, should be kept wet by spraying with water.
Compaction of fill material at the ponds could further reduce dust generation.
Dust emission during loading of fill material to dump trucks, or from dump
trucks to the drained ponds should be mitigated by spraying to sufficiently
damp the materials prior to any loading or unloading operations.
4.4.31
Dusty construction debris
should be covered where practicable to avoid dust generation. Watering is an effective dust control measure
commonly employed in storage piles and handling operations and should be
implemented where appropriate.
Phasing of Construction Activities
4.4.32
The phasing of dusty
construction activities can effectively control the dust generation during the
construction period. The pond filling activities during site formation for the
residential portion of the Project and establishment of WNR will be conducted
in a “portion-by-portion” approach to mitigate dust generation.
4.4.33
With the implementation of the
above-recommended dust mitigation measures together with those required in the
Air Pollution Control (Construction Dust) Regulation, a conservative dust
control efficiency of 75% is considered achievable. (e.g. through regular and
frequent water spraying, say every 2 hours during very dry days or worst dust
situation). Table
4‑5 presents the mitigated dust levels (75% control
efficiency) estimated at the ASRs with the implementation of sufficient dust
emission measures, as recommended above. The fugitive dust impacts have been
predicted to fully satisfy the relevant criteria when the dust control measures
are implemented.
4.4.34
Figure 4‑4 and Figure
4‑5 present the worst-case maximum 1-hour at 10.0 mPD and
24-hour TSP levels at 5.3 mPD in the vicinity of the site predicted by the air
quality model under Stage A. For Stage
B, the worst-case maximum 1-hour and 24-hour TSP concentrations are presented
in Figure
4‑6 and Figure
4‑7 accordingly. The background TSP concentration has
been incorporated into the contours. The contours in Figure 4-4 to Figure 4-7 show the exceedances of hourly and daily average TSP
in some areas within the Subject Site, however, no air sensitive uses were
identified within those areas.
Table 4‑5 Predicted mitigated TSP Level at
selected ASRs
|
Representative ASRs
|
Predicted levels, µg/m3
(Stage A - mitigated)
|
Predicted levels, µg/m3
(Stage B – mitigated)
|
|
Location
|
ASR
|
mPD
|
1-hour TSP
|
24-hour TSP
|
1-hour TSP
|
24-hour TSP
|
|
Village House
(Man
Wa Garden)
|
A1
|
6.3
|
241
|
138
|
237
|
154
|
|
|
9.3
|
196
|
125
|
215
|
144
|
|
|
12.3
|
167
|
116
|
190
|
133
|
|
Village House
|
A2
|
12.2
|
164
|
114
|
152
|
121
|
|
|
15.2
|
150
|
112
|
141
|
117
|
|
|
18.2
|
140
|
110
|
130
|
113
|
|
Village House
|
A3
|
10.0
|
256
|
124
|
151
|
118
|
|
|
13.0
|
236
|
120
|
140
|
116
|
|
|
16.0
|
214
|
117
|
133
|
113
|
|
Village House
|
A4
|
9.6
|
166
|
117
|
183
|
114
|
|
|
12.6
|
158
|
114
|
164
|
111
|
|
|
15.6
|
145
|
110
|
146
|
109
|
|
Village House
(Tin Hau Temple)
|
A5
|
8.9
|
153
|
112
|
184
|
110
|
|
Village House
(Ng Uk
Tsuen)
|
A6
|
11.4
|
134
|
108
|
127
|
105
|
|
Village House
|
A7
|
5.6
|
136
|
107
|
123
|
104
|
|
Village House
|
A8
|
5.6
|
153
|
112
|
134
|
107
|
|
Village House
|
A9
|
5.3
|
233
|
152
|
116
|
106
|
|
Village House
|
A10
|
5.3
|
134
|
115
|
117
|
107
|
|
Village House
|
A11
|
5.6
|
123
|
105
|
114
|
102
|
|
Village House
|
A12
|
5.6
|
118
|
105
|
106
|
102
|
|
Village House
|
A13
|
5.6
|
111
|
103
|
108
|
102
|
|
Village House
|
A14
|
5.6
|
116
|
104
|
106
|
101
|
|
Village House
|
A15
|
5.6
|
120
|
105
|
113
|
103
|
Note: A background TSP level of 100 mg/m3
has been included in the results.
Potential Odour Nuisance during
Construction Phase
4.4.35
Pond sediment which is usually
rich in organic material could pose certain odour nuisance to the surrounding
when they are exposed and in vast amount. Since any exposed surface and stockpiled
material will be covered by impervious sheet or immediately filled by filling
materials during the construction phase, the potential odour nuisance pose by
the exposed pond sediment during dredging and pond filling is considered to be
minimal.
4.4.36
The potential odour nuisance is
considered to be in minor extent or at least similar to the normal pond
draining and dredging activities commonly performed in the existing site as
convential practices of fish farming.
Environmental Monitoring and Audit
4.4.37
Based on the findings of the
foregoing study, it is recommended that an Environmental Monitoring and Audit
(EM&A) Programme be implemented during the construction phase of the
Project to ensure implementation of the recommended dust mitigation measures.
This will enable the contractor to identify the potential dust emission
problems, and to react timely with remedial measures when dust criteria are
about to be exceeded (e.g. more frequent watering of site haul roads). Details of the recommended EM&A on air
quality issues are presented in the EM&A Manual.
Concurrent Construction Activities
4.4.38
The approved EIA of “Yuen Long
and Kam Tin Sewerage and Sewage Disposal Stage 2” (EIA-094/2004) justified that no cumulative impact
with the Fung Lok Wai Project would be anticipated. However, the proposed
sewerage project is now classified as a Category B project under the Public
Works Programme. It is our understanding that Drainage Services Department
(DSD) is preparing to conduct the feasibility study. The final alignment and construction schedule of the sewerage works as discussed in the approved EIA report is not
confirmed. After carrying out and
confirmation of the feasibility study, DSD will initiate the detail design
process and get funding approval from the Legislative Council. It is estimated that DSD will need years to
complete the study, design and approval process. Therefore, no construction
programme is available at the present stage for the proposed sewerage work. On the other hand, construction work for the
proposed residential development at the Subject Site is scheduled to complete
by 2016. Since there
is no anticipated overlapping of construction works between the two projects,
hence cumulative dust impact assessment is considered not necessary.
Impacts Summary
4.4.39
Construction activities have
the potential to generate dust impacts on nearby Air Sensitive Receivers, if
unmitigated. Mitigation measures in the form of various dust suppression
techniques based on those specified in the Air Pollution Control (Construction
Dust) Regulation are proposed. These
dust mitigation measures should be implemented to alleviate dust emission level
arising from activities associated with the construction works to acceptable
levels. The implementation of these mitigation measures should also be checked
by an EM&A programme.
4.5.1
There are no air and odour emission sources within the Project,
except potential odour nuisance from a proposed pump house. However, the pump house will have a setback distance of more
than 150m from the
residential block and any nearby ASRs, and with the
implementation of proper enclosure and ventilation system to divert the odour
emission to odour scrubbing device (e.g. enclosed concrete structure and
activated carbon filter at the air vent of the pump house), no insurmountable
odour impact is anticipated. Further discussions are presented in Section 8.8.2.
4.5.2
A minimum setback distance of 125m is provided between the closest existing
local distributor Fuk Shun Street
and the proposed development. Referring
to the Hong Kong Planning Standard and Guidelines (HKPSG), a buffer distance of
not less than 5m shall be
provided between a local distributor and an open space site for active and
passive recreational uses. In this
regard, sufficient buffer distance will be provided and the buffer requirements
as recommended in the HKPSG could be met. The operational air quality impact
arising from the vehicular emission is considered insignificant.
4.5.3
Given the remoteness of the
chimneys located in the YLIE and the YLSTW from the Development (about 400m and 500m away from the Subject Site
respectively), the operational air quality impact arising from the chimney
emissions from the YLIE and odour from the YLSTW are also considered
insignificant.
4.6.1
Fugitive dust emissions due to
site formation works for the access road, pond filling, spreading and
compaction of fill materials at the residential portion of the Project have
been predicted quantitatively. The hypothetical worst-case scenarios were assessed
by assuming concurrent emissions from all identified major dust emission
sources and under worst-case meteorological conditions.
4.6.2
The findings of the
construction dust emission impact assessment indicate that without adequate
mitigation, fugitive dust levels generated from site formation works could
exceed the hourly TSP limit of 500mg/m3
and the 24-hour TSP limit of 260mg/m3
at some of the nearby air sensitive receivers (ASRs). The movement of trucks on
haul roads was found to be the principal source of excessive dust generation.
4.6.3
Implementation of sufficient
mitigation measures including those specified in the Air Pollution Control
(Construction Dust) Regulation as well as those recommended in this EIA for the
contractor through inclusion of relevant clauses into the Contract
Specification are recommended and are considered effective in this assessment
to reduce fugitive dust impact at the ASRs to within acceptable levels. An
EM&A programme is also recommended for the Project to protect the nearby
air sensitive uses further. During the operational phase of the development,
air quality impact due to industrial emissions and vehicular emissions are
considered minimal.
5.1.1
This section presents an
assessment of the noise impact arising from the construction and operation of
the Project in accordance with the requirements specified under Clause 3.5.2
of the EIA Study Brief. Key issues include construction noise impact arising
from use of powered mechanical equipment (PME) during the construction phase,
and impact due to fixed noise sources during the operational phase. This noise
impact assessment has been carried out following the criteria and guidelines
given in Annexes 5 and 13 of the EIAO TM.
5.1.2
Clause 3.5.2
(v) of the Study Brief requires that the construction noise arising from the
Project be addressed. Relevant
assessments and recommended mitigation measures are presented in this
section. Potential impact from envisaged
fixed noise source(s) as proposed at the Project inception stage has also been
assessed
5.2.1
An EIA of “Agreement No. CE
10/95 – Tin Shui Wai Development Engineering Investigations for Development of
Areas 3, 30 & 31 of the Development Zone and the Reserve Zone” was
completed in 1997 prior to the enactment of EIAO to study further developments
at Tin Shui Wai area. The Tin Shui Wai Ecological Mitigation Area otherwise
known as the International Wetland Park
(it was eventually renamed as Hong
Kong Wetland Park) was accepted as mitigation for a
variety of environmental impacts of the development.
5.2.2
The Hong Kong Tourist
Association and Agriculture, Fisheries and Conservation Department (AFCD)
commissioned a “Hong Kong International Wetland
Park and Visitor Centre Feasibility
Study – Preliminary Environmental Review” in 1999 to further assess the
potential environmental impact of the Hong Kong Wetland
Park.
5.2.3
An EIA on the Designated
Project - “Tin Shui Wai Phase 4 Rail Extension” was conducted by Kowloon-Canton
Railway Corporation in 1999. The study has assessed the impacts of the Phase 4
Light Rail Extension. Its construction work is planned to start by early 2001
and last for approximately 3 years.
5.2.4
The “Review of Yuen Long and
Kam Tin Sewerage and Sewage Treatment Requirements” was completed by Drainage
Service Department. Being part of the “Yuen Long and Kam Tin Sewerage and
Sewage Disposal” (YLKTSSD) scheme recommended by the “Review of Yuen Long and
Kam Tin Sewerage and Sewage Treatment Requirements”, a Study Brief No. ESB-082/2001
was issued on 21 Sept 2001 for an EIA Study for the Designated Project “Yuen
Long and Kam Tin Sewerage and Sewage Disposal Stage 2”.
5.3.1
During the construction phase
of the Project, two concurrent projects are identified within the assessment
area, namely the Hong Kong Wetland Park (HKWP) Phase 2 and the Yuen Long and
Kam Tin Sewerage and Sewage Disposal Stage 2. The possible cumulative noise
impacts are considered insignificant for the following reasons.
5.3.2
The construction of Hong Kong Wetland Park
has been completed and is considered to have no cumulative impact on the
construction work of the Project.
5.3.3
According to the EIA study of
“Yuen Long and Kam Tin Sewerage and Sewage Disposal Stage 2” (EIA-094/2004) approved on 17 June 2004, there are
two schemes proposed – Conforming Scheme of 2A-1T and Alternative scheme of 2A-1. Two of the Designated Projects (DPs) identified
in the project are Package 2A-1T
and its alternative, which are the construction of the Yuen Long Sewerage
Treatment Works (YLSTW) Effluent Pipeline. They will be close to the Project as
they include the construction of pumping station to the north of YLSTW and twin
rising mains. In particular the twin rising mains of Package 2A-1T will be laid from YLSTW to Tin Tsz Road in Tin
Shui Wai via the southern boundary of the Project. EIA-094/2004 concluded that
the Alternative scheme of 2A-1T
which was further away from the Fung Lok Wai Project was the preferred option.
Cumulative impact would not be anticipated as justified in the Sec 2.5 of the
EIA-094/2004. Furthermore, the proposed sewerage project is now classified as a
Category B project under the Public Works Programme. It is our understanding
that Drainage Services Department (DSD) is preparing to conduct the feasibility
study. The final alignment and construction schedule of the sewerage works as discussed in the approved EIA report is not
confirmed. After carrying out and
confirmation of the feasibility study, DSD will initiate the detail design
process and get funding approval from the Legislative Council. It is estimated that DSD will need years to
complete the study, design and approval process. Therefore, no construction
programme is available at the present stage for the proposed sewerage
work. On the other hand, construction
work for the proposed residential development at the Subject Site is scheduled
to complete by 2016. Since
there is no anticipated overlapping of construction works between the two
projects, hence cumulative noise impact assessment is considered not necessary.
5.4.1
Figure 2‑4 in Section 2 presents the assessment area for noise
impact assessment. As stated in the Study Brief, Clause 3.5.2.2
(i), the assessment area is defined by a region of 300m from the boundary of the Project, including the
access road.
5.5.1
Existing and planned NSRs
situated within the assessment area were identified based on the definition
given in Annex 13 of the EIAO TM and are described below. The locations of the
representative assessment points (“RAPs”), i.e. CN1 to CN5 are shown in Figure 5‑1.
Existing Noise Sensitive Receivers
·
Village huts close to the
southern boundary of the Project (Man Wa Garden);
·
Village huts close to the
south-eastern boundary of the Project;
·
Village huts close to the
eastern boundary of the Project;
·
Village huts close to the
northern boundary of the Project;
·
Village hut at the western side
of the Project;
·
Village huts located at the
north-western boundary of the Project;
·
Tin Hau
Temple;
·
Shing Uk Tsuen;
·
Tai Tseng Wai;
·
Ng Uk Tsuen;
·
Vienna Villa;
·
Jade Court;
·
Lai Yin Garden;
·
Leon Court; and
·
Other village houses adjacent
to Fuk Shun Street
5.5.3
The locations of the above NSRs
around the Site are illustrated in Figure 5-2.
Planned Noise Sensitive Receivers
Introduction
5.6.1
This section presents an
assessment of noise impact on surrounding Noise Sensitive Receivers (NSRs)
during the construction phase of the Project. In accordance with the
construction programme, the potential cumulative noise impacts of the
construction of the access road, the residential portion and the WNR have been
assessed.
5.6.2
The assessment of construction
noise impact was in accordance with the methodology stipulated in Para. 5.3 and 5.4 of Annex 13 of the EIAO TM. Noise generated from construction works other
than percussive piling during the non-restricted hours (i.e. 7a.m. to 7 p.m. on weekdays other than
general holidays) is the focus of the study in accordance with the requirement
stated in Clause 3.5.2.2 (v) of the Study Brief.
5.6.3
Representative worst case
scenarios were identified based on the construction programme (see Figure 2‑7).
Legislation and Assessment Criteria
5.6.4
Construction noise is
controlled under the Noise Control Ordinance (NCO) which prohibits the use of
powered mechanical equipment (PME) during the restricted hours (7 p.m. to 7 a.m. on normal weekdays and any time on
a public holiday, including Sunday) without a valid Construction Noise Permit
(CNP) granted by the Authority. The criteria and procedures for issuing such a
permit are specified in the “Technical Memorandum on Noise From Construction
Works Other than Percussive Piling” (TM1).
5.6.5
For construction works other
than percussive piling, although TM1 do not provide control over daytime
construction activities, noise limits are set out in Annex 5 of the EIAO-TM.
The TM applies to designated projects, including residential or recreational
development planned within Deep Bay Buffer Zone 1 or 2. The noise standards are summarised in Table 5‑1.
Table 5‑1 Noise Limits for Daytime Construction Activities
|
NSR
|
0700
to 1900 hours on any day not being a Sunday or general holiday Leq (30min.)
dB (A)
|
|
All domestic premises including temporary
housing accommodation
|
75
|
|
Educational institutions including
kindergartens, nurseries.
|
70
65 (during examination)
|
N.B. (i) The above standards apply to uses which
reply on opened windows for ventilation.;
(ii) The above standards shall be viewed as the
maximum permissible noise levels assessed at 1m from the external facade.
5.6.6
It is understood that whether
the Noise Control Authority will issue a CNP would depend on the application
submitted to the Authority according to the procedures laid down in TM1 issued
under the NCO instead of the assessment presented in this EIA. When assessing an application of a CNP, the
Authority will compare the Corrected Noise Level (CNL) calculated based on the
methodology presented in TM1 with the required Acceptable Noise Level (ANL),
which depends on the noise sensitivity of the NSRs in question and is
determined based on the criteria set out in TM1.
5.6.7
With effect from 1 November
1996, the use of specified powered mechanical equipment (SPME) for carrying out
construction work other than percussive piling and/ or the carrying out of
prescribed construction work (PCW) within a designated area are also brought
under control. The relevant technical details are provided in the “Technical
Memorandum on Noise from Construction Work in Designated Areas” (TM2). Based on
the plan (no. EPD/NP/NT-04) issued by the Planning and Lands Bureau, The
Project is just outside the boundary of the noise control designated areas under
the Noise Control Ordinance.
5.6.8
Percussive piling is controlled
similarly by a noise permit system and described in the NCO and the “Technical
Memorandum On Noise From Percussive Piling” (TM3) which restrict the number of
hours during which piling can be conducted.
No percussive piling may be carried out in the territory without a valid
CNP issued by the Authority. Besides, a
CNP will only be granted for percussive piling, which is scheduled during
normal working hours between 7 a.m.
to 7 p.m. from Monday to Saturday. The
carrying out percussive piling is prohibited at any time on Sundays and public
holidays as well as during the weekday from 7 p.m. to 7
a.m. the next day.
5.6.9
Despite any description or
assessment made in this EIA Report on construction noise aspects, there is no
guarantee that a Construction Noise Permit (CNP) will be issued for the project
construction. The Noise Control Authority will consider a well-justified CNP
application, once filed, for construction works within restricted hours as guided
by the relevant Technical Memorandum issued under the Noise Control Ordinance
(NCO). The Noise Control Authority will take into account of contemporary
conditions/situations of adjoining land uses and any previous complaints
against construction activities at the site before making this decision in
granting a CNP. Nothing in this EIA Report shall bind the Noise Control
Authority is making his decision. If a CNP is to be issued, the Noise Control
Authority shall include in it any
condition he thinks fit. Failure to comply with any such conditions will
lead to cancellation of the CNP and prosecution action under the NCO.
Assessment Methodology
5.6.10
The approach used in the
assessment of noise from construction works other than percussive piling is
based on standard acoustic principles, and the guidelines given Para. 5.3 and 5.4 of Annex 13 of the EIAO TM. The methodology adopted is the same as that
presented in TM1.
5.6.11
The construction area of the
Project is divided into 3 portions as shown in Figure 5‑3 to represent the construction area for access road,
the residential portion and the wetland nature reserve.
5.6.12
Noise impact arising from the
construction works have been predicted using the following typical procedures:
-
·
Based on the tentative
construction programme (see Figure
2‑7), the worst construction scenarios were identified;
·
Identify from TM1 the Sound
Power Level (SWL) of each powered mechanical equipment (PME) preliminarily
planned for used in the construction works;
·
Select representative NSRs for
the construction noise impact assessment;
·
Identify the notional source
position for each representative assessment point (RAP). As it is an elongated site for the
residential portion and an irregular one for the WNR, the dominant construction
portion should be the fish pond nearest to the NSRs, the notional source
position is considered to be at a position mid-way between the approximate
geographical centre of that fish pond and its boundary nearest to the NSRs;
·
For the construction area of
access road, the notional source position is defined as the shortest distance
between the access road and the NSRs;
·
Calculate the Predicted Noise
Level (PNL) based on distance attenuation from notional source positions to the
representative NSRs;
·
With consideration of the
effect of facade reflection at the NSRs, the Corrected Noise Level (CNL) at the
NSRs was predicted; and
·
Based on a comparison of the
CNL with the noise criteria presented in Table
5‑1, situations/ locations where the need for noise
mitigation measures can be identified.
Key Construction Activities and
Assessment Scenarios
5.6.13
As described in Section 2.2, the concerned main construction activities of the
Project which will generate considerable noise impact involve the following:
Table 5‑2 Key Construction Activities for Construction Noise Impact
Assessment
|
Tasks
|
Descriptions
|
|
A
|
Establishment of Wetland Nature Reserve (WNR)
|
|
A1
|
Drain, remove bunds and install water controls at
Sector 1
|
|
A2
|
Drain, remove bunds and install water controls at
Sector 2
|
|
A3
|
Land formation and construction of water control
structures of marshland
|
|
A4
|
Drain, remove bunds and install water controls at
Sector 3
|
|
B
|
Construction works for development area
|
|
B1
|
Site Clearance
|
|
B2
|
Pond draining and dredging
|
|
B3
|
Pond filling
|
|
B4
|
Spreading and compaction of fill material at built area
|
|
B5a
|
Foundation works – Bored piling or H piling
|
|
B5b
|
Remaining Foundation works, including sheet piling and
pile cap construction
|
|
B6
|
Superstructure and steel-bending at work area
|
|
B7
|
Construction of sewage pump house
|
|
B8
|
Laying of drainage, sewerage and utilities
|
|
B9
|
Paving of internal access road
|
|
C
|
Widening works of the access road leading to the Site
|
|
C1
|
Site Clearance and formation
|
|
C2
|
Laying of drainage, sewerage and utilities
|
|
C3
|
Formation of road sub-base, levelling and compaction
|
|
C4
|
Road paving and installation of road furniture
|
5.6.14
The contractor(s) will be
required to carry out the construction works such that the associated noise
impact is minimised as far as possible to comply with the Noise Control
Ordinance (NCO) and the daytime noise limits recommended in the EIAO-TM.
5.6.15
Before the appointment of
contractors, it would not be possible to define in full details of the type and
frequency of utilization of different construction plants, a representative A
Powered Mechanical Equipment (PME) inventory has been worked out and is
considered practicable at this planning stage.
5.6.16
While it is understood that the
future appointed Contractor(s) may propose a different PME inventory, the
carrying out of a representative quantitative assessment at this planning stage
would enable an early focus on the potential noise problem, the practicality
and sufficiency in the noise mitigation measures as proposed and planned at an
early stage.
5.6.17
Appendix 5-1 presents the
preliminary PME Inventory that is considered practicable in meeting the target
construction programme and the Sound Power Levels for each of the PME.
5.6.18
It should be noted that the
percentage of time used for every PME is based on the actual situation of the
construction activities. A reasonable
reduction in percentage on-time can reflect the actual situation which is used
as a basic assumption for specific kind of PME.
5.6.19
As mentioned in Section 5.6.8
above, percussive piling is controlled by a noise permit system
under the NCO and the “Technical Memorandum on Noise from Percussive Piling”
(TM3) which restrict the number of hours during which piling can be conducted.
In order to minimize the noise impact of the construction activities,
percussive piling will not be used in the foundation works. The preliminary PM Inventory and the
assessment with respect to the foundation works (Task B5a of Table
5‑2) are thus assumed employing bored piling only.
Table 5‑3 Representative Assessment Phases studied in the Construction
Noise Impact Assessment
|
Construction Period
|
Possible Concurrent Tasks
performed at site
(Task Ref. no. refers to Table 5‑2)
|
|
2010
|
3rd Q
|
-
|
|
|
4th Q
|
A1
|
|
2011
|
1st Q
|
A2
|
|
|
2nd Q
|
B1
|
|
|
3rd Q
|
B1
|
|
|
4th Q
|
B1+B2+A3+A4
|
|
2012
|
1st Q
|
B2+A3
|
|
|
2nd Q
|
B3+B4
|
|
|
3rd Q
|
B3+B4
|
|
|
4th Q
|
B3+B4
|
|
2013
|
1st Q
|
B4
|
|
|
2nd Q
|
-
|
|
|
3rd Q
|
B5a
|
|
|
4th Q
|
B5a
|
|
2014
|
1st Q
|
B5a
|
|
|
2nd Q
|
B5b
|
|
|
3rd Q
|
B6+B7+C1
|
|
|
4th Q
|
B6+B7+C1
|
|
2015
|
1st Q
|
B6+B8+C2
|
|
|
2nd Q
|
B6+B8+C2
|
|
|
3rd Q
|
B6+B9+C3
|
|
|
4th Q
|
B6+B9+C3
|
|
2016
|
1st Q
|
B6+C3
|
|
|
2nd Q
|
B6+C4
|
|
|
3rd Q
|
B6+C4
|
Emission Inventory of Noise
Sources
5.6.21
Before appointment of the
contractor, full details of the type and number of construction plant to be
used for the construction works are not known. Nevertheless, based on typical
construction activities, a preliminary PME inventory has been drawn up to allow
a representative construction noise impact assessment be conducted. The PME
list is realistic, practical and practicable, although it is formulated on a
preliminary planning stage. The
equipment list is presented in Appendix 5-1. The assessment will give
information on the individual and combined SWLs of the PME that could be
“allowed” given the locations of the nearby Noise Sensitive Receivers (NSRs)
such that the overall noise levels at the NSRs can be controlled within the
daytime construction noise limits. It is
noted that there is no construction works to be carried out during the
restricted hours (7 p.m. to 7 a.m.
on normal weekdays and any time on a public holiday, including Sunday) unless a
valid Construction Noise Permit (CNP) granted by the Authority.
Representative Assessment Points (RAPs)
5.6.24
Existing and planned noise
sensitive receivers within the assessment area that would be affected by
construction noise impact have been identified in Section 5.5.2 and 5.5.4 above.
Representative Assessment Points (RAPs) were selected to represent these
NSRs as illustrated in Figure
5‑1. Based on the
building height of the NSRs, noise levels were predicted at the lowest, medium
and highest noise sensitive floors at each RAP.
RAPs were selected at locations closest to the construction site such
that the assessment should be representative of the worst-case scenario.
5.6.25
Table 1B of the EIAO TM only
gives the noise standards for daytime construction activities at domestic
premises (including temporary housing accommodation), hotels and hostels, and
educational institutions. Locations of the RAPs (CN1 to CN5) are presented in Figure 5‑1. These RAPs are described below in Table 5‑4.
Table 5‑4 RAPs Selected for
Construction Noise Impact Assessment
|
RAP
|
Noise
Sensitive Use
|
Building
Type
|
Assessment
Height (mPD)
|
|
|
Village
Huts near South-western boundary of the site (Man Wa Garden)
|
Low rise residential
|
6.0, 9.0, 12.0
|
|
CN 2
|
Village Huts close to Fuk Shun street (Leon Court)
|
Low rise residential
|
5.9, 8.9, 11.9
|
|
CN 3
|
Village Huts at South-eastern boundary of
the site
|
Low rise residential
|
5.0
|
|
CN 4
|
Village Huts at North-western boundary of
the site
|
Low rise residential
|
5.3
|
|
CN 5
|
Village Hut at northern boundary of the
site
|
Low rise residential
|
5.3
|
Assessment Results (Unmitigated
Scenario)
5.6.26
Table 5‑5 to Table
5‑9 present the unmitigated noise levels predicted at the
RAPs for the identified worst-case representative assessment phases. Those
predicted noise levels exceeding the noise criteria are highlighted in bold.
Worksheet showing the calculation is provided in Appendix 5-2 for reference.
Table 5‑5 Unmitigated Noise Levels Predicted At CN 1
|
|
|
|
Overall PNL , dB(A) at CN1
|
|
Period
|
|
Concurrent Tasks
|
G/F
|
1/F
|
2/F
|
|
2010
|
3rd Q
|
-
|
Not applicable
|
Not applicable
|
Not applicable
|
|
|
4th Q
|
A1
|
76
|
76
|
76
|
|
2011
|
1st Q
|
A2
|
76
|
76
|
76
|
|
|
2nd Q
|
B1
|
77
|
77
|
77
|
|
|
3rd Q
|
B1
|
77
|
77
|
77
|
|
|
4th Q
|
B1+B2+A3+A4
|
83
|
83
|
83
|
|
2012
|
1st Q
|
B2+A3
|
80
|
80
|
80
|
|
|
2nd Q
|
B3+B4
|
80
|
79
|
79
|
|
|
3rd Q
|
B3+B4
|
80
|
79
|
79
|
|
|
4th Q
|
B3+B4
|
80
|
79
|
79
|
|
2013
|
1st Q
|
B4
|
75
|
75
|
75
|
|
|
2nd Q
|
-
|
Not applicable
|
Not applicable
|
Not applicable
|
|
|
3rd Q
|
B5a
|
83
|
83
|
82
|
|
|
4th Q
|
B5a
|
83
|
83
|
82
|
|
2014
|
1st Q
|
B5a
|
83
|
83
|
82
|
|
|
2nd Q
|
B5b
|
82
|
82
|
82
|
|
|
3rd Q
|
B6+B7
|
81
|
81
|
81
|
|
|
4th Q
|
B6+B7+C1
|
87
|
87
|
87
|
|
2015
|
1st Q
|
B6+B8+C1
|
87
|
87
|
87
|
|
|
2nd Q
|
B6+B8+C2
|
87
|
87
|
87
|
|
|
3rd Q
|
B6+B9+C2
|
86
|
86
|
86
|
|
|
4th Q
|
B6+B9+C3
|
83
|
83
|
83
|
|
2016
|
1st Q
|
B6+C3
|
83
|
83
|
82
|
|
|
2nd Q
|
B6+C4
|
82
|
82
|
82
|
|
|
3rd Q
|
B6+C4
|
82
|
82
|
82
|
Table 5‑6 Unmitigated Noise
Levels Predicted At CN 2
|
|
|
|
Overall PNL , dB(A) at CN2
|
|
Period
|
|
Concurrent Tasks
|
G/F
|
1/F
|
2/F
|
|
2010
|
3rd Q
|
-
|
Not applicable
|
Not applicable
|
Not applicable
|
|
|
4th Q
|
A1
|
58
|
58
|
58
|
|
2011
|
1st Q
|
A2
|
58
|
58
|
58
|
|
|
2nd Q
|
B1
|
61
|
61
|
61
|
|
|
3rd Q
|
B1
|
61
|
61
|
61
|
|
|
4th Q
|
B1+B2+A3+A4
|
66
|
66
|
66
|
|
2012
|
1st Q
|
B2+A3
|
63
|
63
|
63
|
|
|
2nd Q
|
B3+B4
|
63
|
63
|
63
|
|
|
3rd Q
|
B3+B4
|
63
|
63
|
63
|
|
|
4th Q
|
B3+B4
|
63
|
63
|
63
|
|
2013
|
1st Q
|
B4
|
58
|
58
|
58
|
|
|
2nd Q
|
-
|
Not applicable
|
Not applicable
|
Not applicable
|
|
|
3rd Q
|
B5a
|
62
|
62
|
62
|
|
|
4th Q
|
B5a
|
62
|
62
|
62
|
|
2014
|
1st Q
|
B5a
|
62
|
62
|
62
|
|
|
2nd Q
|
B5b
|
62
|
62
|
62
|
|
|
3rd Q
|
B6+B7
|
62
|
62
|
62
|
|
|
4th Q
|
B6+B7+C1
|
88
|
87
|
87
|
|
2015
|
1st Q
|
B6+B8+C1
|
88
|
87
|
87
|
|
|
2nd Q
|
B6+B8+C2
|
87
|
87
|
87
|
|
|
3rd Q
|
B6+B9+C2
|
87
|
87
|
87
|
|
|
4th Q
|
B6+B9+C3
|
83
|
83
|
83
|
|
2016
|
1st Q
|
B6+C3
|
83
|
83
|
83
|
|
|
2nd Q
|
B6+C4
|
82
|
82
|
82
|
|
|
3rd Q
|
B6+C4
|
82
|
82
|
82
|
Table 5‑7 Unmitigated Noise
Levels Predicted At CN 3
|
Period
|
|
Concurrent Tasks
|
Overall PNL , dB(A) at CN3 –
G/F
|
|
2010
|
3rd Q
|
-
|
Not applicable
|
|
|
4th Q
|
A1
|
76
|
|
2011
|
1st Q
|
A2
|
75
|
|
|
2nd Q
|
B1
|
70
|
|
|
3rd Q
|
B1
|
70
|
|
|
4th Q
|
B1+B2+A3+A4
|
80
|
|
2012
|
1st Q
|
B2+A3
|
78
|
|
|
2nd Q
|
B3+B4
|
72
|
|
|
3rd Q
|
B3+B4
|
72
|
|
|
4th Q
|
B3+B4
|
72
|
|
2013
|
1st Q
|
B4
|
67
|
|
|
2nd
Q
|
-
|
Not applicable
|
|
|
3rd
Q
|
B5a
|
72
|
|
|
4th Q
|
B5a
|
72
|
|
2014
|
1st Q
|
B5a
|
72
|
|
|
2nd Q
|
B5b
|
72
|
|
|
3rd Q
|
B6+B7
|
72
|
|
|
4th Q
|
B6+B7+C1
|
72
|
|
2015
|
1st Q
|
B6+B8+C1
|
72
|
|
|
2nd Q
|
B6+B8+C2
|
72
|
|
|
3rd Q
|
B6+B9+C2
|
70
|
|
|
4th Q
|
B6+B9+C3
|
70
|
|
2016
|
1st Q
|
B6+C3
|
68
|
|
|
2nd Q
|
B6+C4
|
68
|
|
|
3rd Q
|
B6+C4
|
68
|
Table 5‑8 Unmitigated Noise
Levels Predicted At CN 4
|
|
|
|
Overall PNL , dB(A) at CN4
|
|
Period
|
|
Concurrent Tasks
|
G/F
|
|
2010
|
3rd Q
|
-
|
Not applicable
|
|
|
4th Q
|
A1
|
78
|
|
2011
|
1st Q
|
A2
|
78
|
|
|
2nd Q
|
B1
|
63
|
|
|
3rd Q
|
B1
|
63
|
|
|
4th Q
|
B1+B2+A3+A4
|
82
|
|
2012
|
1st Q
|
B2+A3
|
81
|
|
|
2nd Q
|
B3+B4
|
66
|
|
|
3rd Q
|
B3+B4
|
66
|
|
|
4th Q
|
B3+B4
|
66
|
|
2013
|
1st Q
|
B4
|
61
|
|
|
2nd Q
|
-
|
Not applicable
|
|
|
3rd Q
|
B5a
|
65
|
|
|
4th Q
|
B5a
|
65
|
|
2014
|
1st Q
|
B5a
|
65
|
|
|
2nd Q
|
B5b
|
65
|
|
|
3rd Q
|
B6+B7
|
65
|
|
|
4th Q
|
B6+B7+C1
|
66
|
|
2015
|
1st Q
|
B6+B8+C1
|
66
|
|
|
2nd Q
|
B6+B8+C2
|
66
|
|
|
3rd Q
|
B6+B9+C2
|
65
|
|
|
4th Q
|
B6+B9+C3
|
64
|
|
2016
|
1st Q
|
B6+C3
|
62
|
|
|
2nd Q
|
B6+C4
|
62
|
|
|
3rd Q
|
B6+C4
|
62
|
Table 5‑9 Unmitigated
Noise Levels Predicted At CN 5
|
|
|
|
Overall PNL , dB(A) at CN5
|
|
Period
|
|
Concurrent Tasks
|
G/F
|
|
2010
|
3rd Q
|
-
|
Not applicable
|
|
|
4th Q
|
A1
|
79
|
|
2011
|
1st Q
|
A2
|
79
|
|
|
2nd Q
|
B1
|
57
|
|
|
3rd Q
|
B1
|
57
|
|
|
4th Q
|
B1+B2+A3+A4
|
83
|
|
2012
|
1st Q
|
B2+A3
|
81
|
|
|
2nd Q
|
B3+B4
|
59
|
|
|
3rd Q
|
B3+B4
|
59
|
|
|
4th Q
|
B3+B4
|
59
|
|
2013
|
1st Q
|
B4
|
54
|
|
|
2nd
Q
|
-
|
Not applicable
|
|
|
3rd
Q
|
B5a
|
58
|
|
|
4th Q
|
B5a
|
58
|
|
2014
|
1st Q
|
B5a
|
58
|
|
|
2nd Q
|
B5b
|
58
|
|
|
3rd Q
|
B6+B7
|
58
|
|
|
4th Q
|
B6+B7+C1
|
60
|
|
2015
|
1st Q
|
B6+B8+C1
|
60
|
|
|
2nd Q
|
B6+B8+C2
|
59
|
|
|
3rd Q
|
B6+B9+C2
|
58
|
|
|
4th Q
|
B6+B9+C3
|
57
|
|
2016
|
1st Q
|
B6+C3
|
56
|
|
|
2nd Q
|
B6+C4
|
56
|
|
|
3rd Q
|
B6+C4
|
56
|
5.6.27
Noise levels predicted at all
RAPs would exceed the Leq(30min) 75dB(A) by 1-13dB(A). Construction noise
mitigation measures are therefore necessary to protect the NSRs represented by
all RAPs.
5.6.28
It should be noted that the
assessment results only represent the worst-case construction scenarios i.e.
when equipment adopted for different construction activities are in concurrent
and continuous operation, and located at the same notional source position
nearest to each RAP in question. In reality, the occurrence of these scenarios
would be rare. Nevertheless, the assessment results revealed that particular
attention should be paid to implement sufficient control/ mitigation measures
to alleviate the noise impact during the construction, especially near the RAPs
which are in close proximity to the construction site of the Project. The
construction site of the Project includes the construction area of the
residential footprint, wetland nature reserve and the access road to the site.
Recommended Construction Noise
Mitigation Measures
5.6.29
Noise emissions from
construction sites can be minimised by adopting a combination of practicable
noise mitigation options, such as:
·
Use of quiet equipment;
·
Erecting temporary noise
barriers and Provision of Noise Enclosure;
·
Phasing of the Construction
Activities;
·
Reduce the number of equipment;
·
Good site practice and noise
management; and
·
Use of silenced PME.
Selecting Quiet PME
5.6.30
Silenced types of equipment for
use in construction activities are available in Hong Kong. For each item of PME listed in Appendix 5-1,
the SWL of quieter plant were identified from TM1 or BS 5228 Noise and
vibration control on construction and open sites: Part I: 1997 for the purpose
of the assessment. The SWL of the silenced PME are presented in Appendix 5-3.
It is recommended that the contractor should diligently seek equivalent models
of silenced PME with a SWL similar to or less than that presented in that
table.
5.6.31
Table 5‑10 to Table 5‑14 present the mitigated noise levels predicted at CN1
to CN5 when silenced PME with the reduced SWL presented in Appendix 5-3 are in
employed. Worksheets showing calculation of noise levels are provided in
Appendix 5-4 for reference.
5.6.32
It can be observed that by
adopting the silenced type of PME, the noise levels at the RAPs will be
substantially reduced. Despite this, the
noise criteria will still be exceeded at CN1 and CN2 by a
maximum noise level of 1-6 dB(A).
Table 5‑10 Mitigated Noise Levels at CN1 with Silenced PME
|
|
|
|
Overall
PNL , dB(A) at CN1
|
|
Period
|
|
Concurrent
Tasks
|
G/F
|
1/F
|
2/F
|
|
2010
|
3rd Q
|
-
|
Not applicable
|
Not applicable
|
Not applicable
|
|
|
4th Q
|
A1
|
67
|
67
|
67
|
|
2011
|
1st Q
|
A2
|
67
|
67
|
67
|
|
|
2nd Q
|
B1
|
66
|
66
|
66
|
|
|
3rd Q
|
B1
|
66
|
66
|
66
|
|
|
4th Q
|
B1+B2+A3+A4
|
73
|
73
|
73
|
|
2012
|
1st Q
|
B2+A3
|
71
|
71
|
71
|
|
|
2nd Q
|
B3+B4
|
71
|
71
|
71
|
|
|
3rd Q
|
B3+B4
|
71
|
71
|
71
|
|
|
4th Q
|
B3+B4
|
71
|
71
|
71
|
|
2013
|
1st Q
|
B4
|
69
|
69
|
69
|
|
|
2nd
Q
|
-
|
Not applicable
|
Not applicable
|
Not applicable
|
|
|
3rd
Q
|
B5a
|
81
|
81
|
81
|
|
|
4th Q
|
B5a
|
81
|
81
|
81
|
|
2014
|
1st Q
|
B5a
|
81
|
81
|
81
|
|
|
2nd Q
|
B5b
|
76
|
76
|
76
|
|
|
3rd Q
|
B6+B7
|
71
|
71
|
71
|
|
|
4th Q
|
B6+B7+C1
|
77
|
77
|
76
|
|
2015
|
1st Q
|
B6+B8+C1
|
78
|
78
|
77
|
|
|
2nd Q
|
B6+B8+C2
|
78
|
78
|
78
|
|
|
3rd Q
|
B6+B9+C2
|
77
|
77
|
77
|
|
|
4th Q
|
B6+B9+C3
|
79
|
79
|
79
|
|
2016
|
1st Q
|
B6+C3
|
79
|
79
|
78
|
|
|
2nd Q
|
B6+C4
|
74
|
74
|
74
|
|
|
3rd Q
|
B6+C4
|
74
|
74
|
74
|
Table 5‑11 Mitigated Noise Levels
at CN2 with Silenced PME
|
|
|
|
Overall
PNL , dB(A) at CN2
|
|
Period
|
|
Concurrent
Tasks
|
G/F
|
1/F
|
2/F
|
|
2010
|
3rd Q
|
-
|
Not applicable
|
Not applicable
|
Not applicable
|
|
|
4th Q
|
A1
|
49
|
49
|
49
|
|
2011
|
1st Q
|
A2
|
49
|
49
|
49
|
|
|
2nd Q
|
B1
|
49
|
49
|
49
|
|
|
3rd Q
|
B1
|
49
|
49
|
49
|
|
|
4th Q
|
B1+B2+A3+A4
|
56
|
56
|
56
|
|
2012
|
1st Q
|
B2+A3
|
53
|
53
|
53
|
|
|
2nd Q
|
B3+B4
|
54
|
54
|
54
|
|
|
3rd Q
|
B3+B4
|
54
|
54
|
54
|
|
|
4th Q
|
B3+B4
|
54
|
54
|
54
|
|
2013
|
1st Q
|
B4
|
53
|
53
|
53
|
|
|
2nd
Q
|
-
|
Not applicable
|
Not applicable
|
Not applicable
|
|
|
3rd
Q
|
B5a
|
61
|
61
|
61
|
|
|
4th Q
|
B5a
|
61
|
61
|
61
|
|
2014
|
1st Q
|
B5a
|
61
|
61
|
61
|
|
|
2nd Q
|
B5b
|
56
|
56
|
56
|
|
|
3rd Q
|
B6+B7
|
53
|
53
|
53
|
|
|
4th Q
|
B6+B7+C1
|
77
|
77
|
76
|
|
2015
|
1st Q
|
B6+B8+C1
|
77
|
77
|
76
|
|
|
2nd Q
|
B6+B8+C2
|
78
|
77
|
77
|
|
|
3rd Q
|
B6+B9+C2
|
78
|
77
|
77
|
|
|
4th Q
|
B6+B9+C3
|
79
|
79
|
79
|
|
2016
|
1st Q
|
B6+C3
|
79
|
79
|
79
|
|
|
2nd Q
|
B6+C4
|
74
|
74
|
73
|
|
|
3rd Q
|
B6+C4
|
74
|
74
|
73
|
Table
5‑12 Mitigated Noise Levels
at CN3 with Silenced PME
|
|
|
|
Overall PNL , dB(A) at CN3
|
|
Period
|
|
Concurrent Tasks
|
G/F
|
|
2010
|
3rd Q
|
-
|
Not
applicable
|
|
|
4th Q
|
A1
|
66
|
|
2011
|
1st Q
|
A2
|
66
|
|
|
2nd Q
|
B1
|
58
|
|
|
3rd Q
|
B1
|
58
|
|
|
4th Q
|
B1+B2+A3+A4
|
71
|
|
2012
|
1st Q
|
B2+A3
|
69
|
|
|
2nd Q
|
B3+B4
|
63
|
|
|
3rd Q
|
B3+B4
|
63
|
|
|
4th Q
|
B3+B4
|
63
|
|
2013
|
1st Q
|
B4
|
62
|
|
|
2nd Q
|
-
|
Not
applicable
|
|
|
3rd Q
|
B5a
|
71
|
|
|
4th Q
|
B5a
|
71
|
|
2014
|
1st Q
|
B5a
|
71
|
|
|
2nd Q
|
B5b
|
66
|
|
|
3rd Q
|
B6+B7
|
62
|
|
|
4th Q
|
B6+B7+C1
|
63
|
|
2015
|
1st Q
|
B6+B8+C1
|
65
|
|
|
2nd Q
|
B6+B8+C2
|
65
|
|
|
3rd Q
|
B6+B9+C2
|
63
|
|
|
4th Q
|
B6+B9+C3
|
63
|
|
2016
|
1st Q
|
B6+C3
|
62
|
|
|
2nd Q
|
B6+C4
|
62
|
|
|
3rd Q
|
B6+C4
|
62
|
Table 5‑13 Mitigated Noise Levels
at CN4 with Silenced PME
|
|
|
|
Overall PNL , dB(A) at CN4
|
|
Period
|
|
Concurrent Tasks
|
G/F
|
|
2010
|
3rd Q
|
-
|
Not applicable
|
|
|
4th Q
|
A1
|
69
|
|
2011
|
1st Q
|
A2
|
69
|
|
|
2nd Q
|
B1
|
52
|
|
|
3rd Q
|
B1
|
52
|
|
|
4th Q
|
B1+B2+A3+A4
|
73
|
|
2012
|
1st Q
|
B2+A3
|
71
|
|
|
2nd Q
|
B3+B4
|
57
|
|
|
3rd Q
|
B3+B4
|
57
|
|
|
4th Q
|
B3+B4
|
57
|
|
2013
|
1st Q
|
B4
|
55
|
|
|
2nd
Q
|
-
|
Not applicable
|
|
|
3rd
Q
|
B5a
|
63
|
|
|
4th Q
|
B5a
|
63
|
|
2014
|
1st Q
|
B5a
|
63
|
|
|
2nd Q
|
B5b
|
58
|
|
|
3rd Q
|
B6+B7
|
56
|
|
|
4th Q
|
B6+B7+C1
|
57
|
|
2015
|
1st Q
|
B6+B8+C1
|
58
|
|
|
2nd Q
|
B6+B8+C2
|
59
|
|
|
3rd Q
|
B6+B9+C2
|
57
|
|
|
4th Q
|
B6+B9+C3
|
58
|
|
2016
|
1st Q
|
B6+C3
|
57
|
|
|
2nd Q
|
B6+C4
|
56
|
|
|
3rd Q
|
B6+C4
|
56
|
Table 5‑14 Mitigated Noise Levels at CN5 with Silenced PME
|
|
|
|
Overall PNL , dB(A) at CN5
|
|
Period
|
|
Concurrent Tasks
|
G/F
|
|
2010
|
3rd Q
|
-
|
Not applicable
|
|
|
4th Q
|
A1
|
69
|
|
2011
|
1st Q
|
A2
|
69
|
|
|
2nd Q
|
B1
|
45
|
|
|
3rd Q
|
B1
|
45
|
|
|
4th Q
|
B1+B2+A3+A4
|
74
|
|
2012
|
1st Q
|
B2+A3
|
72
|
|
|
2nd Q
|
B3+B4
|
50
|
|
|
3rd Q
|
B3+B4
|
50
|
|
|
4th Q
|
B3+B4
|
50
|
|
2013
|
1st Q
|
B4
|
49
|
|
|
2nd Q
|
-
|
Not applicable
|
|
|
3rd Q
|
B5a
|
57
|
|
|
4th Q
|
B5a
|
57
|
|
2014
|
1st Q
|
B5a
|
57
|
|
|
2nd Q
|
B5b
|
52
|
|
|
3rd Q
|
B6+B7
|
49
|
|
|
4th Q
|
B6+B7+C1
|
50
|
|
2015
|
1st Q
|
B6+B8+C1
|
52
|
|
|
2nd Q
|
B6+B8+C2
|
52
|
|
|
3rd Q
|
B6+B9+C2
|
51
|
|
|
4th Q
|
B6+B9+C3
|
51
|
|
2016
|
1st Q
|
B6+C3
|
51
|
|
|
2nd Q
|
B6+C4
|
49
|
|
|
3rd Q
|
B6+C4
|
49
|
Use of Temporary Noise Barriers and
Machinery Enclosures
5.6.33
The erection of temporary
mobile noise barriers between noise sources and NSRs will be effective in
reducing the potential construction noise impact, especially for the low-rise
village huts which are the target NSRs to be protected.
5.6.34
The minimum effective height of
the mobile noise barriers should be such that no part of the noise sources
should be visible from the target NSRs to be protected. The guidelines given in
the Booklet entitled “A Practical Guide for the Reduction of Noise from
Construction Works” issued by EPD is recommended to be referenced to in the
design of the temporary acoustic barriers. Barriers should have no openings or
gaps, and preferably have a superficial surface density of at least 10 kg/m2. Where required, temporary barriers of
sufficient height with skid footing and a cantilevered upper portion can be
erected within a few meters from stationary plants, and at practicable distance
from mobile plants operating over a small area or using a well defined route,
to alleviate potential construction noise impact.
5.6.35
Particular attention should be
drawn to bored piling works at the residential area where they are considered
the major construction noise sources. Noise barriers are recommended to be
erected close to the stationary point of piling works during piling to alleviate
the potential noise impact to the adjacent village huts.
5.6.36
To the NSRs along Fuk Shun Street
which are represented by CN2, the widening works of access road is considered
the major noise nuisance during the construction phase. Considering the close
proximity of the village huts (CN2) to the construction site of access road,
setting up of a noise barrier with approximate 3m height between the noise source and those village
huts along Fuk Shun Street
is considered necessary during the construction works of access road. Given the
low-rise nature of those village huts (1 to 3 storeys only), most noise sources
should be completely shielded from the target NSRs after the erection of these
noise barriers. The barrier effect is anticipated to provide a noise reduction
effect of at least 10dB(A).
5.6.37
In addition to temporary mobile
noise barriers, certain types of PME such as generators and compressors can be
totally shielded by machine enclosures, giving a noise reduction of 10dB(A) or
more.
5.6.38
It is expected that the proper
use of barriers/ enclosures for PME can achieve a noise reduction of 10dB(A)
when the noise barriers completely hides the sources from the receiver in
accordance with BS 5228. To be
conservative, a –5dB(A) reduction has been applied for mobile noise sources.
With the erection of proper designed noise barriers, a 10dB(A) noise reduction
has been applied in the calculation of the construction noise attributed to
excavation and piling works. For generators and compressors which can be
effectively enclosed to minimize noise generation, a –10dB(A) noise reduction
has also been applied in the calculation.
Appendix 5-5 presents the reduced SWL of the PME when the noise
reduction effect of noise barriers and machinery enclosures are applied.
5.6.39
Table 5‑15 to Table
5‑16 present the further mitigated noise levels predicted
at CN1 and CN2 when temporary noise barriers and machinery enclosures are also
used on-site in addition to silenced PMEs.
Noise levels at CN3, CN4 and CN5 are not further assessed, as the
predicted construction noise levels with silenced PMEs in place would meet the
noise criteria. Worksheet showing the calculation at CN1 and CN2 of the
worst scenario is provided in Appendix 5-6 for reference.
5.6.40
The results of the calculation
as presented show that with the combined use of silenced PME, noise barriers
and machinery enclosures, the construction noise levels at all RAPs can be
mitigated to acceptable levels.
Table
5‑15 Mitigated Noise Levels at CN1 with Silenced PME + Temporary
Noise Barriers + Machinery Enclosure
|
|
|
|
Overall PNL , dB(A) at CN1
|
|
Period
|
|
Concurrent Tasks
|
G/F
|
1/F
|
2/F
|
|
2010
|
3rd Q
|
-
|
Not applicable
|
Not applicable
|
Not applicable
|
|
|
4th Q
|
A1
|
63
|
63
|
63
|
|
2011
|
1st Q
|
A2
|
63
|
63
|
63
|
|
|
2nd Q
|
B1
|
63
|
63
|
63
|
|
|
3rd Q
|
B1
|
63
|
63
|
63
|
|
|
4th Q
|
B1+B2+A3+A4
|
69
|
69
|
69
|
|
2012
|
1st Q
|
B2+A3
|
67
|
67
|
67
|
|
|
2nd Q
|
B3+B4
|
67
|
67
|
67
|
|
|
3rd Q
|
B3+B4
|
67
|
67
|
67
|
|
|
4th Q
|
B3+B4
|
67
|
67
|
67
|
|
2013
|
1st Q
|
B4
|
64
|
64
|
64
|
|
|
2nd Q
|
-
|
Not applicable
|
Not applicable
|
Not applicable
|
|
|
3rd Q
|
B5a
|
71
|
71
|
71
|
|
|
4th Q
|
B5a
|
71
|
71
|
71
|
|
2014
|
1st Q
|
B5a
|
71
|
71
|
71
|
|
|
2nd Q
|
B5b
|
71
|
71
|
71
|
|
|
3rd Q
|
B6+B7
|
64
|
64
|
64
|
|
|
4th Q
|
B6+B7+C1
|
72
|
72
|
72
|
|
2015
|
1st Q
|
B6+B8+C1
|
73
|
73
|
73
|
|
|
2nd Q
|
B6+B8+C2
|
74
|
74
|
73
|
|
|
3rd Q
|
B6+B9+C2
|
73
|
73
|
73
|
|
|
4th Q
|
B6+B9+C3
|
74
|
74
|
74
|
|
2016
|
1st Q
|
B6+C3
|
74
|
73
|
73
|
|
|
2nd Q
|
B6+C4
|
70
|
70
|
70
|
|
|
3rd Q
|
B6+C4
|
70
|
70
|
70
|
Table 5‑16 Mitigated Noise Levels at
CN2 with Silenced PME + Temporary Noise Barriers + Machinery Enclosure
|
|
|
|
Overall
PNL , dB(A) at CN2
|
|
Period
|
|
Concurrent
Tasks
|
G/F
|
1/F
|
2/F
|
|
2010
|
3rd
Q
|
-
|
Not applicable
|
Not applicable
|
Not applicable
|
|
|
4th
Q
|
A1
|
45
|
45
|
45
|
|
2011
|
1st
Q
|
A2
|
45
|
45
|
45
|
|
|
2nd
Q
|
B1
|
46
|
46
|
46
|
|
|
3rd
Q
|
B1
|
46
|
46
|
46
|
|
|
4th
Q
|
B1+B2+A3+A4
|
52
|
52
|
52
|
|
2012
|
1st
Q
|
B2+A3
|
49
|
49
|
49
|
|
|
2nd
Q
|
B3+B4
|
50
|
50
|
50
|
|
|
3rd
Q
|
B3+B4
|
50
|
50
|
50
|
|
|
4th
Q
|
B3+B4
|
50
|
50
|
50
|
|
2013
|
1st
Q
|
B4
|
48
|
48
|
48
|
|
|
2nd Q
|
-
|
Not applicable
|
Not applicable
|
Not applicable
|
|
|
3rd Q
|
B5a
|
51
|
51
|
51
|
|
|
4th
Q
|
B5a
|
51
|
51
|
51
|
|
2014
|
1st
Q
|
B5a
|
51
|
51
|
51
|
|
|
2nd
Q
|
B5b
|
51
|
51
|
51
|
|
|
3rd
Q
|
B6+B7
|
46
|
46
|
46
|
|
|
4th
Q
|
B6+B7+C1
|
73
|
73
|
73
|
|
2015
|
1st
Q
|
B6+B8+C1
|
73
|
73
|
73
|
|
|
2nd
Q
|
B6+B8+C2
|
74
|
74
|
73
|
|
|
3rd
Q
|
B6+B9+C2
|
74
|
74
|
73
|
|
|
4th
Q
|
B6+B9+C3
|
74
|
74
|
74
|
|
2016
|
1st
Q
|
B6+C3
|
74
|
74
|
74
|
|
|
2nd
Q
|
B6+C4
|
70
|
70
|
70
|
|
|
3rd
Q
|
B6+C4
|
70
|
70
|
70
|
Other Noise Mitigation Measures
Recommended
5.6.41
The assessment results
presented above demonstrate with the use of silenced PME, temporary noise
barriers and machinery enclosure, noise levels at the NSRs will be mitigated to
acceptable levels. To be prudent in noise
control, additional measures are recommended below.
Phasing of Construction Activities
5.6.42
The noise levels predicted at
the NSRs presented in Table
5‑5 to Table
5‑16 are based on concurrent operation of all equipment at
all time within a 30-minute period. In
real life situations, it is expected that under the construction programme,
different construction activities could be arranged in sequences such that
different PMEs do not necessary have to be in operation concurrently.
Cumulative noise impact arising from the construction site can therefore be
minimizedGood Housekeeping
5.6.43
Significant noise impact during
the construction phase can be avoided when noise management is regarded one of
the key components of the construction works.
The following good site practices are recommended for incorporation into
contract document.
·
Contractor shall comply with
and observe the Noise Control Ordinance (NCO) and its current subsidiary
regulations;
·
Before the commencement of any
work, the Contractor shall submit to the Engineer for approval the method of
working, equipment and sound-reducing measures intended to be used at the site;
·
Contractor shall devise and
execute working methods that will minimise the noise impact on the surrounding
environment; and shall provide experienced personnel with suitable training to
ensure that these methods are implemented;
·
Only well-maintained plants
should be operated on-site;
·
Plants should be serviced
regularly during the construction programme;
·
Machines that may be in
intermittent use should be shut down or throttled down to a minimum between
work periods;
·
Silencer and mufflers on
construction equipment should be utilised and should be properly maintained
during the construction programme;
·
Noisy activities can be
scheduled to minimise exposure of nearby NSRs to high levels of construction
noise. For example, noisy activities can
be scheduled for midday or at times coinciding with periods of high background
noise (such as during peak traffic hours);
·
Noisy equipment such as
emergency generators shall always be sited as far away as possible from noise
sensitive receivers;
·
Mobile plants should be sited
as far away from NSRs as possible; and
·
Material stockpiles and other
structures should be effectively utilised as noise barrier, where practicable.
Reduce No. of PME operating together in Areas close to the Boundary
of the Site
5.6.44
Construction noise can be
reduced by increasing the distance between the operating equipment and the NSRs
or by reducing the number of equipment items in use simultaneously. By controlling the number of equipment
(particularly those relatively noisy one) working near the existing NSRs or the
boundary of the site, potential construction noise impact can be further
reduced.
EM&A Requirements
5.6.45
In order to protect the nearby
NSRs from unacceptable construction noise impact, an environmental monitoring
and audit (EM&A) programme should be implemented to check the proper use of
noise mitigation measures and noise management. Details on the noise monitoring
requirements, methodology and action plans are described in details in the
EM&A Manual
Conclusion
5.6.46
The construction noise impact
assessment revealed that unmitigated noise levels predicted at some existing
dwellings located close to the Project site would exceed the EIAO-TM
requirements, if not mitigated properly.
5.6.47
Mitigation measures in form of
use of silenced equipment, noise barriers, and machinery enclosure, phasing of
construction activities, good housekeeping practices, and reduced numbers of
equipment operating together close to the NSRs and the boundary of the site
have been recommended as effective measures to reduce the construction noise
impact.
Introduction
5.7.1
This section presents an
assessment of the noise impact during the operational phase of the Project in
accordance with Clause 3.5.2.2 (vi) of
the Study Brief. Issue of concern will be the fixed noise impact that could be
associated with major on-site installations, which may affect the future
residential development – the nearest noise sensitive uses to the sources
envisaged.
Fixed Noise Sources
Legislation and Assessment Criteria
5.7.2
Noise standards required to be met at NSRs for
noise generated from fixed noise sources are stated in
the Technical Memorandum for the Assessment of Noise from Places other than
Domestic Premises, Public Places or Construction Sites (TM4). In order to plan for a better environment, in
accordance with the requirements under Table 1
in Annex 5 of the EIAO-TM, the maximum noise level arising from
the noise sources, measured in terms of Leq(30 min) at the NSRs shall be 5
dB(A) below the Acceptable Noise Level (ANL) as specified in TM4.
5.7.3
In determining the ANL,
appropriate Area Sensitivity Rating (ASR) for a NSR have to be established first.
Section 2.3.4 of the TM specifies that the
Area Sensitivity Rating depends upon the characteristics of the area in which
the NSRs are located. There are four
types of areas described in the TM, which are summarised in Table 5-17 below.
According to the rural nature of the subject site not affected by any
Influencing Factor (IF), an ASR “A” was assumed for residential blocks within
the Project and also the village huts at the surrounding.
5.7.4
For ASR “A”, the ANL for the
daytime/ evening (0700-2300) and night-time (2300-0700 next day) periods
measured at 1m in front
of the building facade of the NSR shall be Leq(30min.) 60 dB(A) and 50 dB(A),
respectively. Taking into account the
EIAO-TM requirements, a “5dB(A) margin has been applied to the noise limits stipulated
in the TM. The noise assessment criteria adopted in this study are therefore
Leq(30min.) 55 dB(A) and 45 dB(A) during the daytime/ evening and night time
periods, respectively.
Table 5‑17 Area Sensitivity Ratings of NSRs
|
Type of Area Containing
NSR
|
Degree to which NSR is
affected by Influencing Factors (Ifs)
|
|
|
Not Affected
|
Indirectly
Affected
|
Directly
Affected
|
|
(i)
Rural
area, including country parks, or village type developments
|
A
|
B
|
B
|
|
(ii)
Low
density residential area consisting of low-rise or isolated high-rise
developments
|
A
|
B
|
C
|
|
(iii)
Urban
area
|
B
|
C
|
C
|
|
(iv)
Area
other than those above
|
B
|
B
|
C
|
Assessment Approach
5.7.5
The assessment on fixed plant
noise impact was conducted based standard acoustics principles presented in TM4
and are summarized below:
·
Based on the preliminary design
layout plans and equipment inventory required to be provided at the new
facility, identify the key noise sources of potential concern;
·
Estimate the sound power levels
(SWL) associated with operation of each of these activities based on available
measurement results or typical SWL figures;
·
Calculate the Corrected Noise
Level (CNL) at selected representative NSRs based on consideration of distance
attenuation, noise shielding effect, and façade correction;
·
Compare the CNL with the
relevant noise criteria and recommend noise mitigation measures if necessary.
Noise Impact Evaluation
5.7.6
No electricity sub-station is
likely to be built in the subject site. Only small-scale transformer room(s)
may be found at the proposed development. Although the information such as
design, specification and location of the transformer room(s) was not yet
available, since the transformer room is likely to be enclosed inside concrete
structure, its noise impact is considered minimal.
5.7.7
A review of the design for the
Project suggests that the planned sewage pump house within the residential
portion of the Project will be the only major noise source during the
operational phase. Other activities, e.g. the management and operation of the
WNR should not be causing unacceptable noise impact on the surroundings. The
pump for the recirculation of water to the ponds at the WNR is just for
emergency use. Alhough the detail design of the pump was no yet confirmed.
Considering its small in scale needed, and its very limited usage of time and
duration, the operational noise impact from the pump for the recirculaion of
water at the WNR is considered minimal.
5.7.8
Due to the relatively lower
topography of the site, the conveyance of sewage generated by the residential
development to nearby Government sewage treatment works should be accomplished
by pumping.
5.7.9
Reference is made to the
Drainage Service Department (DSD)’s standard design on the latest sewerage
pumping station, which is totally enclosed by 100mm thick concrete wall. The opening of the pumping
station will usually be located away from any NSRs. According to the approved
“Comprehensive Feasibility Study for the Revised Scheme of South East Kowloon
Development - Environmental Impact Assessment Report” Appendix 3c and the “Sound Analysis and Noise Control,
John Forman, 1990, Van Nostrand Reinhold, Table
5‑5, pp. 154”,
the noise attenuation effect caused by building enclosure can be up to 29
dB(A).
5.7.10
The proposed pump house will be
made reference to the DSD’s standard design on the latest sewerage pumping
station which will be a totally enclosed building with 100mm thick concrete wall. A design will also be adopted to avoid any
opening or louvers, if any, facing the nearest NSR.
5.7.11
The proposed pump house design
envisaged for the residential development will be made reference to larger
district pumping stations which can provide more conservation assumptions. With
reference to the approved “Drainage Service Department Agreement No. CE 29/2001
Outlying Islands Sewerage Stage 1 Phase 1 Ngong Ping Sewage Treatment Works and
Sewerage Investigation, Design and Construction – Final EIA” Appendix 4B and
with taking into account of the tonal, impulsive and intermittent characteristic
and effects of the pump operation, the sound power level of the pump would be
100 dB(A). A calculation of the likely impact is presented as follows: -
Sound power level (SWL) of one pump =
100 dB(A)
Sound power level (SWL) of two duty and one
standby pumps = 103 dB(A)
Minimum setback distance of the NSR from
the pump house = 150 m
Distance attenuation =
-52 dB(A)
Façade correction =
3 dB(A)
Noise reduction due to building enclosure =
-29 dB(A)
Corrected Noise Level at the
nearest NSR, [Leq (30min)] =
25 dB(A)
5.7.12
It is obvious that the above
can comfortably be achieved for pump house of a size suitable for a residential
development of this scale in terms of the minimum setback distance and the
power (hence the sound power) needed. The attenuation in noise impact should be
enough to enable compliance with the assessment criteria given in Section 5.6.4
above.
5.7.13
Subject to the selected
sewerage option and the final design of the MLP and the pump house, it is
expected to be housed inside a concrete structure near the car-park area for
the visitors with openings at the southern side facing away from any NSRs. The
pump house will have a setback distance of more than 150m from the residential block, and any nearby NSRs.
Construction
Phases
5.8.1
A quantitative construction
noise impact assessment has been conducted to predict the potential
construction noise impact on Noise Sensitive Receivers situated in the vicinity
of the development site. The study has been carried out in accordance with
procedures outlined in the “Technical Memorandum on Noise from Construction
Work Other Than Percussive Piling”.
Based on the preliminary construction programme and an equipment
inventory, the likely construction noise levels at the nearby NSRs were predicted
for a number of worst construction scenarios.
5.8.2
Control/ mitigation measures
should be implemented to reduce the noise impact arising from the construction
works as far as practicable for the protection of the NSRs. Mitigation measures
recommended include use of silenced equipment, erection of temporary noise
barriers, use of noise enclosure, phasing of construction activities, good site
practice and noise management, and reduce number of equipment operating near
the site boundary and in the vicinity of NSRs.
5.8.3
With these mitigation measures
in place, the predicted construction noise impact at all NSRs will be reduced
to acceptable levels.
5.8.4
The implementation of these
noise mitigation measures during the construction phase is recommended to be
monitored by an EM&A programme as described in the EM&A Manual.
Operational Phase
5.8.5
Sewage pump house at the
residential portion of the Project is the only major noise source identified to
be of concern to the future noise sensitive receivers. Based on conservative
assumptions of the possible noise power levels for the sewage pump house, the
noise impact was evaluated and has been found to be acceptable if a minimum
setback of 150m (or less
for smaller pumps) is observed. The pumps should be housed inside a concrete
structure with openings facing away from any NSRs.
6.
Water quality impact assessment
6.1.1
This section presents an
assessment of the potential water quality impact that may arise from
construction and operation of the Project.
The assessment has been carried out in accordance with the requirements
given in Clause 3.5.3 of the EIA Study Brief and the
criteria and guidelines as stated in Annexes 6 and 14 of the EIA-TM
respectively.
6.1.2
The “assessment area” covers
fishponds surrounding the Subject Site and surrounding areas in the larger Deep
Bay Catchment Area of the Deep Bay Water Control Zone (WCZ), the Mai Po Inner Deep Bay Ramsar Site,
and Hong Kong Wetland Park
as shown in Figure
6‑1.
General
6.2.1
The Subject Site is situated
close to the Inner
Deep Bay
with some 43 ha of the
Site is designated as Mai Po Inner Deep
Bay Ramsar Site since September 1995. The site lies within Wetland Conservation
Area, which is subject to planning control for protecting the adjoining Mai Po Inner Deep Bay Ramsar Site
from incompatible land uses. The Site is also close to the Hong Kong Wetland
Park (HKWP) and the Mai Po
area to its northeast. The Subject Site is abutted by fishponds on 3 sides with
a village situated to the south.
6.2.2
Early maps and aerial
photographs suggested that the Site was formerly part of an extensive swamp
that existed around the fringes of Deep
Bay. During this century
the swamp has gradually been reclaimed first for paddy cultivation and later
for fish and duck ponds.
6.2.3
The Site is a flat low-lying
area divided by low earth bunds into a mosaic of fishponds used for fish
farming. Water systems in the vicinity of the Site are mainly drainage
channels, natural rivers, fishponds, wetland, and marine waters etc.
Drainage channels within the Subject Site
6.2.4
At the Site, the level on top
of the fishpond bunds varies from approximately +3.1 to +3.3 mPD, at the north
and east to about +4.2 mPD at the south. All of the catchments upstream of the
Site drain via 3 unlined drainage channels within and adjacent to the Site into
two river channels leading to the Inner
Deep Bay.
The two drainage channels flowing to the west discharge to the Deep Bay via
one of the tidal channels – the Tai
River forming the delta
to the Tin Shui Wai catchment drainage system. The other drainage channel
flowing to the east discharges into Deep
Bay via the San Pui
River. None of the 3 drainage channels on-site includes control structures, and
therefore water levels are controlled by both fluvial and surge tide
conditions. The locations of these water bodies and catchments are illustrated
in Figure
6‑2.
Tai
River
6.2.5
The Tai River
flows beside the northwestern part of the Subject Site, and receives flow from
its southwestern catchment.
6.2.6
The Tai River
is a mangrove-lined channel and is intertidal. The perimeter bunds abutting the
Tai River are approximately +3.8 mPD and are
higher than the predicted mean high water in the channel (+2.4 m PD). Under normal circumstances,
the interior of the Subject Site remains free of tidal influence. Overtopping
of the perimeter might occur in an extreme combined high tide and storm event.
However, this is likely to be extremely rare given the past extreme sea levels
at nearby Tsim Bei Tsui to the northwest of the Subject Site, which peaked at
+3.85 mPD with a return period of 100 years for records between 1974 and 1990.
The predicted tidal range for 2002 at Tsim Bei Tsui is 0-3 mPD with an average
peak tide of +2.4 mPD.
Shan Pui
River
6.2.7
The Shan Pui River is lying east of the Subject Site,
and is the downstream section of the Yuen Long Creek with a length of 60km and a catchment area of about 26.7km2. Limited water
circulation in the Inner
Deep Bay
has enhanced sedimentation and retention of pollutants in the creek (EPD,
1999). To reduce the tidal effects and odour problems in the lower creek, an
inflatable dam and a dry weather flow channel were installed at Yuen Long
Nullah to prevent back flushing from Deep
Bay.
6.2.8
Shan Pui
River collects stormwater drainage discharge from catchment within the
southeast part of the Subject Site and areas to the immediate southeast apart
from catchment flow in Yuen Long area carried by Yuen Long Creek.
6.2.9
Flooding has been a major
problem in the North West
New Territories. As part of the Main Drainage Channel Project
for Ngau Tam Mei, Yuen Long and Kam Tin, Shan Pui River was widened and channelised to
form a 3.3km long
trapezoidal-shaped drainage channel. The new channel is mainly unlined except
for a 0.46km
section located upstream of the confluence with the existing Kam Tin River. The downstream un-lined section
has a constant bed level of about -0.65mPD (ERM, 1996). Width of the channel
ranges from 80m at
upstream to 320m at the
downstream section. The drainage works
at Shan Pui River
commenced in October 1993 and were completed in mid 1999.
Tin Shui Wai Nullah
6.2.10
Tin Shui Wai Nullah collects
catchment flows from areas southwest of Inner
Deep Bay
and drains to Inner
Deep Bay
eventually. It is a concrete channel built to collect runoff. The Hong Kong Wetland Park
to the west of the Subject Site is developed alongside the Nullah.
6.2.11
The exit points of Tai River
and Shan Pui River
are situated over 180 m and 460 m respectively from the boundary of the
Subject Site. The exit point of Tin Shui Wai Nullah is located further away
from the Subject Site at some 600m
apart.
Marine Waters
and Ramsar Site
6.2.12 The Deep Bay Water Control Zone (WCZ) was gazetted on 1 December
1990. The WCZ covers the Mai
Po Marshes together with the inner Deep Bay
area. It contains 4 Sites of Special Scientific Interest (SSSIs), including Inner Deep Bay, Mai Po Marshes,
Tsim Bei Tsui and Tsim Bei Tsui Egretry. Oyster beds were found near Lau Fau
Shan, Sheung Pak Nai and Ha Pak Nai. The
estuarine mud flats of Inner
Deep Bay
are of international importance for migrating and wintering birds.
6.2.13 The Mai Po
Marshes and Inner
Deep Bay
are classified as Mai Po Inner Deep
Bay Ramsar Site included in the Ramsar List of Wetlands of International Importance
(Ramsar List) in 1995. The Convention on Wetlands, signed in Ramsar, Iran,
in 1971, is an inter-governmental treaty, which provides the framework for
national action and international cooperation for the conservation and wise use
of wetlands and their resources.
Wetlands included in the Ramsar List acquire a new status at the
national level and are recognized by the international community as being of
significant value not only for the country, or the countries, in which they are
located, but also for humanity as a whole.
6.2.14 Deep Bay is located on the east bank of the Pearl Estuary. It is a shallow bay and has a surface area of
about 112 km2. During mean sea level, it contains
approximately 330 Mm3 of
water. The rivers of interest that drain
into Deep Bay include Shenzhen River on the PRC side, River Indus, River Beas,
River Ganges, Yuen Long Creek, and Kam Tam River on the Hong Kong SAR side. Shenzhen River
provides approximately 55% of the annual runoff into Deep Bay.
Fishponds and Wetland
6.2.15
There are altogether 105 nos.
of fishponds within the study area amongst which 46 of the fishponds that
occupy a total area of 60ha
are currently actively managed and 10 of fishponds with a total area of 10ha have already been abandoned within the
site boundary. Abandoned fishpond within the Subject Site concentrates mainly
at the southern part.
6.2.16
The Subject Site is surrounded
by existing fishponds to the immediate north, east and west. Three tidal ponds are located to the
immediate north of the Subject Site. Marine water and water in these three
ponds mix together during high tide. Further north is a shallow wetland area
where the Inner Deep Bay SSSI is located.
6.2.17
In the past, water in actively
managed fishponds was drained into the Inner Deep Bay during heavy storm to avoid any
overflow that may affect the fisheries. For the abandoned fishponds, it is
logically assumed that water will flow over the access and bunds to the other
fishponds as well as to other water bodies nearby upon overflow due to
flooding.
Hong Kong Wetland Park
6.2.18
Hong Kong Wetland Park is situated to the west of the Subject Site, which is built as a
compensation for the development of the Tin Shui Wai new town area. The wetland
park has a total area of about 64 ha.
Hong Kong Wetland Park
provides created fresh water marshes and mud flats, as well as different types
of habitats including grassland, mixed woodland, paddy fields, fishponds and
mangrove.
6.2.19
Hong Kong Wetland Park creates a green
buffer between the Tin Shui Wai new town development and the nearby Mai Po Marshes to the
northeast of the Subject Site.
6.3.1
Clause 3.5.3.4
(ii) of the Brief requires the characterisation of water and sediment quality
of the natural/ artificial watercourses and manmade fishponds based on existing
information or site survey.
6.3.2
A water and sediment quality
survey covering the potential water sensitive receivers in the vicinity of the
Project and the potential pollution sources such as fishpond water and mud has
been conducted in May 2002 to record the baseline water and sediment quality
prior to the construction and operational phases of the Project.
6.3.3
To make good use of the
existing comprehensive data, the EPD routine water and sediment monitoring
results have been reviewed to characterize the surrounding environment of the
study area as far as possible. These data have the advantages of their
abundance and completeness and are representative of seasonal and long-term
trends.
6.3.4
Additional sampling data have
also been obtained in-situ by the Consultant to fill the information gap of the
existing water quality at the downstream of nearby rivers, which are close to
the Subject Site and selected fishponds therein.
Marine Water Quality
6.3.5
There are 5 monitoring stations
in the Deep Bay WCZ with DM1, DM2 and DM3 located in the inner sub-zone and DM4
and DM5 in Outer Deep
Bay. Amongst all, DM1 is
the nearest monitoring station to the Subject Site. Locations of these
monitoring stations are shown in Figure
6‑3.
6.3.6
Water quality in the Deep Bay
WCZ is not considered satisfactory with the inner bay polluted even more. The
monitored 5-day Biochemical Oxygen Demand (BOD5), suspended solids (SS) and
inorganic nutrient levels support this assertion.
6.3.7
At DM1, the monitored levels of
Dissolved Oxygen (DO) ranges from 1.3 to 6.3 mg/L. About 80% of the samples
have levels less than 4mg/L. This means that the DO objective was hardly met.
Low DO was occasionally observed in the Inner Deep Bay during summer, indicating anoxic
conditions. The total inorganic nitrogen (TIN) at all stations in the Inner Deep
Bay did not comply with
the WQO; while the unionised ammonia (NH3-N) was also recorded at above WQO levels except in
the outer reaches of the bay. This persistently non-compliance signifies
nutrient pollution problem in the Inner
Deep Bay.
6.3.8
DO levels have improved when
compared with earlier data in 1999 whereas the nutrient level increases at the
same time. E.coli levels, on the other hand, experience a long-term increase,
which can be attributed to faecal pollution problem in the Inner Deep Bay.
6.3.9
In summary, Deep Bay
water quality is characterised by long-term pollution including nutrient
enrichment, ammonia toxicity and bacterial contamination. This has led to
Government’s effort to
exercise more stringent control in this WCZ.
6.3.10
Table 6‑1 below
summarises the marine water quality of the Deep Bay WCZ in 2005.
Table 6‑1 Summary Statistics of
Marine Water Quality of Deep Bay WCZ in 2005 (Inner Deep Bay)
|
Determinant
|
Inner Deep
Bay
|
|
DM1
|
DM2
|
DM3
|
|
Number of samples
|
12
|
12
|
12
|
|
Temperature (oC)
|
24.2
|
24.2
|
24.2
|
|
|
(15.7 – 31.8)
|
(15.6 – 32.1)
|
(16.1 – 31.5)
|
|
Salinity (psu)
|
16.6
|
18.5
|
21.5
|
|
|
(1.8 – 24.1)
|
(3.1 – 27.0)
|
(4.1 – 30.0)
|
|
Dissolved Oxygen (mg/L)
|
2.9
|
4.3
|
5.3
|
|
|
(1.3 – 6.3)
|
(2.2 – 9.0)
|
(4.1 – 7.2)
|
|
Bottom
|
NM
|
NM
|
NM
|
|
Dissolved Oxygen (% Saturation)
|
38
|
57
|
72
|
|
|
(16 - 87)
|
(26 - 106)
|
(56 - 89)
|
|
Bottom
|
NM
|
NM
|
NM
|
|
pH
|
7.5
|
7.6
|
7.8
|
|
|
(7.0 – 8.0)
|
(7.1 – 8.2)
|
(7.3 – 8.3)
|
|
Secchi Disc Depth (m)
|
0.3
|
0.4
|
0.6
|
|
|
(0.2 – 0.5)
|
(0.2 – 0.6)
|
(0.2 – 1.0)
|
|
Turbidty (NTU)
|
42.7
|
40.4
|
38.0
|
|
|
(21.2 – 80.7)
|
(16.1 – 96.4)
|
(12.9 – 87.6)
|
|
Suspended Solids (mg/L)
|
49.5
|
42.4
|
40.7
|
|
|
(12.0 - 130)
|
(15.0 - 100)
|
(7.8 – 93.0)
|
|
5-day Biochemical Oxygen Demand (mg/L)
|
5.0
|
3.8
|
1.7
|
|
|
(2.1 – 8.9)
|
(1.7 – 7.7)
|
(0.4 – 3.9)
|
|
Ammonia Nitrogen (mg/L)
|
4.84
|
3.00
|
0.75
|
|
|
(2.10 – 6.80)
|
(1.20 – 4.90)
|
(0.27 – 1.40)
|
|
Unionised Ammonia (mg/L)
|
0.096
|
0.060
|
0.025
|
|
|
(0.023 – 0.460)
|
(0.015 – 0.164)
|
(0.005 – 0.075)
|
|
Nitrite Nitrogen (mg/L)
|
0.29
|
0.38
|
0.25
|
|
|
(0.13 – 0.48)
|
(0.20 – 0.75)
|
(0.16 – 0.37)
|
|
Nitrate Nitrogen (mg/L)
|
0.35
|
0.51
|
0.73
|
|
|
(0.08 – 1.20)
|
(0.23 – 1.70)
|
(0.27 – 2.00)
|
|
Total Inorganic Nitrogen (mg/L)
|
5.48
|
3.89
|
1.73
|
|
|
(3.68 – 7.01)
|
(3.20 – 5.58)
|
(0.99 – 2.87)
|
|
Total kjeldahi Nitrogen (mg/L)
|
5.79
|
3.68
|
1.19
|
|
|
(2.60 – 8.40)
|
(1.50 – 6.10)
|
(0.47 – 2.00)
|
|
Total Nitrogen (mg/L)
|
6.43
|
4.56
|
2.17
|
|
|
(4.18 – 8.61)
|
(3.50 – 6.78)
|
(1.47 – 3.18)
|
|
Orthophosphate Phosphorus (mg/L)
|
0.48
|
0.35
|
0.13
|
|
|
(0.23 – 0.65)
|
(0.18 – 0.53)
|
(0.07 – 0.19)
|
|
Total Phosphorus (mg/L)
|
0.68
|
0.48
|
0.21
|
|
|
(0.45 – 0.93)
|
(0.23 – 0.75)
|
(0.10 – 0.31)
|
|
Silica (as SIO2) (mg/L)
|
6.1
|
5.0
|
3.5
|
|
|
(1.0 – 11.0)
|
(1.2 – 9.9)
|
(0.8 – 7.3)
|
|
Chlorophyll-a (μg/L)
|
35.9
|
15.7
|
6.3
|
|
|
(0.6 - 260)
|
(0.4 - 140)
|
(0.2 – 39.0)
|
|
E.coli (cfu/100mL)
|
9800
|
1300
|
150
|
|
|
(2100 - 360000)
|
(160 - 26000)
|
(2 - 3800)
|
|
Faecal Coliforms (cfu/100mL)
|
17000
|
3100
|
430
|
|
|
(3000 - 740000)
|
(270 - 91000)
|
(8 - 5600)
|
Note: 1.
Except as specified, data presented are depth-averaged (A) values calculated by
taking the means of three depths: Surface (S), Mid-depth (M), and Bottom (B).
2.
Data presented are annual arithmetic means of depth-averaged results except for
E.coli and faecal coliforms, which are annual geometric means.
3.
Data in brackets indicate the ranges.
4.
NM- not
measured.
Marine Sediment Quality
6.3.11
There are 4 monitoring stations
DS1, DS2, DS3 and DS4 located within Deep Bay WCZ. DS1 and DS2 are located in
the inner sub-zone. DS1, which overlap with the location of DM1, is the nearest
monitoring station to the subject site. Heavy metals, trace organics,
electrochemical potential and others were monitored at these monitoring
stations with locations shown in Figure
6‑4. Table
6‑2 summarizes the marine bottom sediment quality of Deep
Bay WCZ from 2001 to 2005. There is a higher concentration of ammonical nitrogen, total sulphide, zinc and high
molecular weight PAHs in DS1. On the other hand, highly
anaerobic sediments are found, which are subject to the deposition of fish
excreta and excessive feedstock on the seabed, resulting in anoxic situation.
Table
6‑2 Summary Statistics of Marine Bottom
Sediment Quality of Deep Bay WCZ, 2001 -2005
|
Determinant
|
Inner Deep
Bay
|
|
DS1
|
DS2
|
|
Number of samples
|
10
|
|
10
|
|
|
Particle Size
Fractionation <63um (%w/w)
|
68
|
(8 - 92)
|
79
|
(63 – 90)
|
|
Electrochemical
Potential (mV)
|
-273
|
(-366 to –145)
|
-175
|
(-272 to –34)
|
|
Total Solids
(%w/w)
|
47
|
(34 – 53)
|
47
|
(43 – 50)
|
|
Total Volatile
Solids (%w/w)
|
6.6
|
(4.7 – 7.8)
|
6.9
|
(6.0 –7.5)
|
|
Chemical Oxygen
Demand (mg/kg)
|
20000
|
(15000 –25000)
|
17000
|
(12000 – 19000)
|
|
Total Carbon
(%w/w)
|
0.6
|
(0.4 – 0.7)
|
0.6
|
(0.5 – 0.7)
|
|
Ammonical Nitrogen
(mg/kg)
|
42.9
|
(2.5 – 230)
|
10.5
|
(<0.05 – 53.0)
|
|
Total Kjeldahl Nitrogen (mg/kg)
|
383
|
(210 – 750)
|
391
|
(160-510)
|
|
Total Phosphorus
(mg/kg)
|
259
|
(110 - 580)
|
291
|
(140 – 380)
|
|
Total Sulphide
(mg/kg)
|
365
|
(22 – 1200)
|
124
|
(29 – 320)
|
|
Total Cyanide
(mg/kg)
|
0.2
|
(<0.1 – 0.3)
|
0.2
|
(<0.1 – 0.6)
|
|
Arsenic (mg/kg)
|
11.2
|
(8.5 – 14.0)
|
13.2
|
(9.9 – 18.0)
|
|
Cadmium (mg/kg)
|
0.3
|
(<0.1 – 0.6)
|
0.3
|
(0.1 – 0.4)
|
|
Chromium (mg/kg)
|
40
|
(28 – 56)
|
41
|
(22 – 49)
|
|
Copper (mg/kg)
|
56
|
(16 – 100)
|
57
|
(26 – 70)
|
|
Lead (mg/kg)
|
59
|
(39 – 86)
|
57
|
(30 – 87)
|
|
Mercury (mg/kg)
|
0.12
|
(<0.05 – 0.29)
|
0.14
|
(0.06 – 0.23)
|
|
Nickel (mg/kg)
|
25
|
(18 – 33)
|
26
|
(14 – 29)
|
|
Silver (mg/kg)
|
0.8
|
(<0.2 – 2.0)
|
0.8
|
(<0.2 – 1.0)
|
|
Zinc (mg/kg)
|
195
|
(100 – 380)
|
180
|
(91 – 240)
|
|
Total
Polychlorinated Biphenyls (PCBs) (ug/kg)
|
18
|
(18 – 18)
|
18
|
(18 – 18)
|
|
Low Molecular
Wight Polycyclic Aromatic Hydrocarbons (PAHs) (ug/kg) (3) (5)
|
92
|
(90 –104)
|
92
|
(90 – 96)
|
|
High Molecular
Weight Polycyclic Armoatic Hydrocarbons (PAHs) (ug/kg) (4) (5)
|
104
|
(18 –355)
|
99
|
(54 – 190)
|
Note: 1. Data presented are arithmetic means;
data in brackets indicate ranges.
2. All data are based on
the analyses of bulk (unsieved) sediment and are reported on a dry weight basis
unless stated otherwise.
3. Low molecular weight
polyaromatic hydrocarbons (PAHs) include 6 congeners of
molecular weight below 200, namely: Acenaphthylene, Acenaphthene, Flourence, Naphthalene, Phenanthrene and Anthracene.
4.
High molecular weight polyaromatic hydrocarbons (PAHs) include 10 congeners
with molecular weight above 200,
namely: Fluoranthene, Pyrene, Benzo(a)anthracene, Chrysene,
Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(a)pyrene,
Dibenzo(a,h)anthracene, Benzo(g, h, i)perylene and Indeno(1,2,3-cd)pyrene.
5. Low Molecular Weight PAHs results are based on sediment samples collected in 2002-2005
only.
6. N.D.: Not detected –
all congeners are below the detection limits.
River Water Quality
6.3.12
There are a number of river
monitoring stations located within Deep Bay WCZ. The directly related
monitoring stations are the four stations, YL1, YL2, YL3 and YL4 at Yuen Long
Creek and the two stations, KT1 and KT2 at Kam
Tin River,
which eventually flow to the downstream river (Shan
Pui River)
to Inner Deep Bay.
Furthermore, the two stations, TSR1 and TSR2, at Tin Shui Wai Nullah flow to
the same water body (Inner
Deep Bay)
eventually. No monitoring station exists for Tai River.
6.3.13
Water Quality Index (WQI) is a
numerical value summarising the general quality of a river. Referring to data
in 2005, the Water Quality Index (WQI) in Yuen Long Creek are graded either
“very bad” or “bad” in 2005. The water quality in Yuen Long Creek are far from satisfactory.
The unsewered villages and livestock farms are expected to be the main sources
of pollution.
6.3.14
Similar to Yuen Long Creek, Kam Tin
River has been severely
impacted by unsewered villages and livestock wastes. The WQI in Kam Tin
River was graded “bad” in
2005. The locations and WQI of EPD’s monitoring stations at Yuen Long
Creek (YL1 to YL4) and Kam
Tin River
(KT1 and KT2) are shown in Figure
6‑5.
6.3.15
On the other hand, the WQI in
Tin Shui Wai Nullah, which is a concrete channel further away from the Subject
Site, have been improved to “fair” and “good” respectively for TSR1 and TSR2 in 2005. The locations and
WQI of EPD’s monitoring stations at Tin Shui Wai Nullah are shown in Figure 6‑5.
6.3.16
No monitoring station exists
for Tai River so that no information is
available regarding to its water quality.
6.3.17
Table 6‑3 has summarized the river water quality of Yuen Long
Creek, Kam Tin River
and Tin Shui Wai Nullah in 2005.
Catchment Water Quality
6.3.18
All the catchments (Catchment
A, B and C) for the drainage channels within the Subject Site are dominated by
dense semi-natural scrub and woodland vegetation. There are no apparent point
sources of pollutants such as pig farms etc. Water from catchment flow is
likely to be of relatively low nutrient and Biological Oxygen Demand (BOD)
content. It is also anticipated that suspended solid (mainly silt) in runoff
during heavy rainfall periods is relatively low due to the existing dense
vegetation cover in the catchments.
Table 6‑3 Summary of River Water
Quality Monitoring results for Yuen Long Creek, Kam Tin River and Tin Shui Wai
Nullah in 2005
|
Parameters
|
Unit
|
Sampling Station
|
|
Yuen Long Creek
|
Kam Tin River
|
Tin Shui Wai Nullah
|
|
YL1
|
YL2
|
YL3
|
YL4
|
KT1
|
KT2
|
TSR1
|
TSR2
|
|
Dissolved oxygen
|
mg/L
|
3.9
|
6.6
|
3.1
|
3.6
|
4.3
|
3.8
|
7.6
|
10.1
|
|
|
|
(1.8 - 7.8)
|
(3.2 - 9.9)
|
(1.5 - 7.8)
|
(1.6 - 6.9)
|
(1.2 - 7.1)
|
(1.7 - 7.2)
|
(1.6 - 10.6)
|
(8.0 - 12.4)
|
|
PH
|
|
7.4
|
7.4
|
7.4
|
7.2
|
7.3
|
7.3
|
7.5
|
8.7
|
|
|
|
(7.1 - 7.8)
|
(7.1 - 8.1)
|
(7.1 - 7.7)
|
(7.0 - 7.5)
|
(7.1 - 7.4)
|
(7.1 - 7.5)
|
(7.1 - 8.4)
|
(7.6 - 9.3)
|
|
Suspended Solids
|
mg/L
|
25
|
15
|
58
|
47
|
18
|
36
|
13
|
13
|
|
|
|
(2 - 100)
|
(3 - 53)
|
(10 - 130)
|
(25 - 220)
|
(5 – 750)
|
(3 - 200)
|
(2 - 46)
|
(4 - 820)
|
|
5-day Biochemical
|
mg/L
|
38
|
8
|
80
|
74
|
14
|
52
|
12
|
1
|
|
Oxygen Demand
|
|
(6 - 130)
|
(5 - 20)
|
(18 - 150)
|
(24 - 120)
|
(6 - 740)
|
(5 - 150)
|
(5 - 27)
|
(1 - 5)
|
|
Chemical Oxygen
|
mg/L
|
46
|
19
|
88
|
93
|
22
|
74
|
13
|
7
|
|
Demand
|
|
(6- 360)
|
(11 - 59)
|
(24 - 410)
|
(30 - 180)
|
(10 - 1600)
|
(8 - 210)
|
(8 - 60)
|
(2 - 12)
|
|
Oil & grease
|
mg/L
|
0.9
|
0.5
|
4.9
|
6.4
|
0.5
|
3.6
|
0.5
|
0.5
|
|
|
|
(0.5 - 15.0)
|
(0.5 – 0.9)
|
(0.5 - 15.0)
|
(0.7 - 23.0)
|
(0.5 - 140.0)
|
(0.5 - 40.0)
|
(0.5 - 3.1)
|
(0.5 - 1.0)
|
|
Faecal coliforms
|
cfu/
|
740,000
|
100,000
|
3,100,000
|
3,900,000
|
550,000
|
970,000
|
630,000
|
41,000
|
|
|
100mL
|
(84,000 – 4,700,000)
|
(29,000 - 330,000)
|
(1,200,000 - 9,000,000)
|
(1,400,000 – 26,000,000)
|
(54,000 - 3,200,000)
|
(150,000 – 5,000,000)
|
(100,000 - 7,900,000)
|
(3,600 - 350,000)
|
|
E coli
|
cfu/
|
510,000
|
42,000
|
1,900,000
|
1,300,000
|
150,000
|
730,000
|
250,000
|
15,000
|
|
|
100mL
|
(38,000 - 3,900,000)
|
(8,000 - 180,000)
|
(660,000 - 6,500,000)
|
(360,000 – 4,700,000)
|
(24,000 – 1,700,000)
|
(80,000 – 3,700,000)
|
(39,000 - 4,100,000)
|
(600 - 110,000)
|
|
Ammonia-nitrogen
|
mg/L
|
24.50
|
7.30
|
12.50
|
4.20
|
9.65
|
15.00
|
2.20
|
0.15
|
|
|
|
(0.62 – 59.00)
|
(1.50 - 16.00)
|
(4.20 - 40.00)
|
(2.30 - 24.00)
|
(1.00 - 27.00)
|
(0.98 - 43.00)
|
0.73 - 7.50)
|
(0.04 - 2.00)
|
|
Nitrate nitrogen
|
mg/L
|
0.12
|
1.50
|
0.01
|
0.01
|
0.59
|
0.01
|
0.96
|
1.25
|
|
|
|
(0.01 – 1.30)
|
(0.47 - 3.00)
|
(0.01 - 1.30)
|
(0.01 - 0.03)
|
(0.01 - 1.00)
|
(0.01 - 0.72)
|
(0.01 - 2.40)
|
(0.69 - 2.00)
|
|
Total Kjeldahl
|
mg/L
|
29.50
|
8.45
|
18.0
|
7.85
|
11.40
|
20.00
|
3.00
|
0.45
|
|
nitrogen. SP
|
|
(1.40 - 72.0)
|
(2.50 - 19.00)
|
(5.80 - 61.00)
|
(3.8 - 33.00)
|
(1.70 - 84.00)
|
(1.50 - 58.00)
|
(1.50 – 12.00)
|
(0.13 - 2.50)
|
|
Ortho-phosphate
|
mg/L
|
3.10
|
1.65
|
2.05
|
0.58
|
1.85
|
3.05
|
0.15
|
0.03
|
|
|
|
(0.23 – 7.50)
|
(0.52 - 4.90)
|
(0.85 - 6.90)
|
(0.25 - 3.80)
|
(0.47 - 8.30)
|
(0.36 - 8.60)
|
(0.06 - 0.70)
|
(0.02 - 0.28)
|
|
Total phosphorus,
|
mg/L
|
3.65
|
2.00
|
3.05
|
1.25
|
2.45
|
4.15
|
0.36
|
0.05
|
|
SP
|
|
(0.37 - 11.0)
|
(0.74 - 5.90)
|
(1.20 - 11.00)
|
(0.56 - 5.10)
|
(0.63 - 26.00)
|
(0.48 - 11.00)
|
(0.22 - 1.30)
|
(0.02 - 0.39)
|
|
Sulphide, SP
|
mg/L
|
0.04
|
0.02
|
0.06
|
0.05
|
0.03
|
0.06
|
0.02
|
0.02
|
|
|
|
(0.02 - 0.75)
|
(0.02 - 0.10)
|
(0.02 - 0.19)
|
(0.02 - 0.09)
|
(0.02 - 2.40)
|
(0.02 - 0.43)
|
(0.02 - 0.18)
|
(0.02 - 0.02)
|
|
Aluminium
|
μg/L
|
200
|
230
|
260
|
295
|
110
|
110
|
155
|
170
|
|
|
|
(90 - 280)
|
(80 - 580)
|
(100 - 540)
|
(100 - 1,200)
|
(50 - 230)
|
(50 - 450)
|
(50 - 430)
|
(90 - 980)
|
|
Cadmium
|
μg/L
|
0.10
|
0.10
|
0.10
|
0.10
|
0.10
|
0.10
|
0.10
|
0.10
|
|
|
|
(0.10 - 0.20)
|
(0.10 - 0.20)
|
(0.10 - 0.3)
|
(0.10 - 0.30)
|
(0.10 - 0.30)
|
(0.10 - 0.30)
|
(0.10 - 0.20)
|
(0.10 - 0.30)
|
|
Chromium
|
μg/L
|
1.0
|
1.0
|
2.0
|
1.0
|
1.0
|
1.0
|
1.0
|
1.0
|
|
|
|
(1.0 - 3.0)
|
(1.0 - 2.0)
|
(1.0 - 5.0)
|
(1.0 - 5.0)
|
(1.0 - 3.0)
|
(1.0 - 5.0)
|
(1.0 - 14.0)
|
(1.0 - 1.0)
|
|
Copper
|
μg/L
|
19.0
|
7.0
|
23.0
|
5.0
|
8.0
|
11.0
|
5.0
|
2.0
|
|
|
|
(2.0 - 573.0)
|
(4.0 - 29.0)
|
(7.0 - 59.0)
|
(2.0 - 32.0)
|
(3.0 - 47.0)
|
(3.0 - 65.0)
|
(2.0 - 21.0)
|
(1.0 - 11.0)
|
|
Lead
|
μg/L
|
4.0
|
4.0
|
5.0
|
6.0
|
2.0
|
2.0
|
3.0
|
2.0
|
|
|
|
(2.0 - 6.0)
|
(1.0 - 8.0)
|
(2.0 - 16.0)
|
(2.0 - 24.0)
|
(1.0 - 4.0)
|
(1.0 - 19.0)
|
(1.0 - 15.0)
|
(1.0 - 97.0)
|
|
Zinc
|
μg/L
|
100
|
55
|
75
|
60
|
45
|
85
|
75
|
20
|
|
|
|
(20 - 240)
|
(20 - 110)
|
(30 - 340)
|
(20 - 360)
|
(20 - 180)
|
(20 - 510)
|
(20 – 1,500)
|
(10 - 120)
|
|
Flow
|
L/s
|
166
|
120
|
615
|
230
|
474
|
158
|
NM
|
84
|
|
|
|
(32 - 990)
|
(68 - 255)
|
(250 – 1,523)
|
(64 - 518)
|
(75 - 2,000)
|
(8 – 1,323)
|
|
(20 – 1,575)
|
Note:
1. Data presented are in
annual medians of monthly samples; except those for faecal coliforms and E.
coli, which are in annual geometric means.
2. Figures in brackets are
annual ranges.
3. NM indicates no
measurement taken.
4. Cfu – colony forming
unit.
5. SP – soluble and
particulate fractions (i.e. total value).
6. Values at or below
laboratory reporting limits are presented as laboratory reporting limits.
7. Equal values for annual
medians and ranges indicate that all data are the same as or below laboratory
reporting limits.
Fishpond Water and Sediment Quality
6.3.19
In the “Objection to Draft Lau
Fau San & Tsim Bei Tsui Outline Zoning Plan S/YL/-lFS/1 Lot 1457 R.P., D.D.
123 – Fung Lok Wai Alternative Proposal”, water quality sampling has been
conducted in 6 fishponds at Fung Lok Wai in 1995. The results are shown as follow. The mean DO
level amounts to more than 3 times of the DO objective of Deep bay WCZ. The
mean pH value falls within the range specified in the WQO. The salinity is not
more than 3 ppt and would not contribute to any significant change. There is,
however, no SS, nutrient and E.coli level available.
Table 6‑4 Results Of Water Quality Monitoring In
Fishponds At Fung Lok Wai (1995)
|
|
Mature ponds
|
Recently filled ponds
|
|
|
No. 8
|
No. 10
|
No. 53
|
Mean
|
No. 11
|
No. 38
|
No. 76
|
Mean
|
|
Temperature (oC)
|
13.9
|
14.15
|
14.25
|
14.1
|
13.5
|
13.35
|
14.65
|
13.83
|
|
Dissolved oxygen (mg l-1)
|
11.95
|
11.59
|
7.48
|
10.34
|
15.41
|
13.44
|
10.22
|
13.02
|
|
Dissolved oxygen sat. (%)
|
117.4
|
115.05
|
74.25
|
102.23
|
150.4
|
127.8
|
102.25
|
126.82
|
|
pH
|
8.15
|
8.25
|
7.94
|
8.11
|
8.51
|
8.54
|
7.85
|
8.3
|
|
Salinity (ppt)
|
2
|
3
|
2
|
2.3
|
3
|
3
|
3
|
3
|
|
Turbidity (Nephelometric Turbidity Units)
|
100.75
|
20.95
|
23.45
|
48.38
|
33.05
|
53.6
|
21.85
|
36.17
|
Note: All
measurements taken by C.E.S. (Asia) Ltd on 3/2/95.
See Figure
2‑9 “the Pond Numbering System” for the location of
ponds.
Source: Objection to Draft Lau Fau San
& Tsim Bei Tsui Outline Zoning Plan S/YL/-lFS/1 Lot 1457 R.P. D.D. 123 –
Fung Lok Wai Alternative Proposal
Further Water and Sediment Quality
Survey
6.3.20
To confirm the current baseline
pond water and sediment quality at the Subject Site, pond water and sediment
samples were collected by a HOKLAS accredited laboratory at a selection of 6
and 2 ponds respectively for laboratory analysis (see Figure 6‑6 and Figure
6‑7 for locations of these ponds). Furthermore, in order to fill the information
gap of the river water quality of the river downstream in the vicinity, water
samples were also collected downstream of Tai River (W2) and Shan Pui River
(W1). The river water quality sampling
locations is shown in Figure
6‑8.
6.3.21
The selected pond water
sampling locations include active fishponds (Pond no. 2, 56, 59, and 62) and
abandoned ones (Pond no. 13 and 19).
Sampled fishpond no. 2, 13 and 56 are located in the area for the
proposed WNR whilst sampled fishpond no. 19, 59 and 62 are situated at the
footprint of the proposed Residential Development. Also, the selected sediment
sampling ponds (Pond no. 19 and 62) will coincide with the footprint of the
proposed Residential Development.
6.3.22
Table 6‑5 and Table
6‑6 present the results of survey on fishponds/ river
water and fishpond sediment quality respectively.
Table 6‑5 Results of Fishpond/
River Water Quality Survey at Fung Lok Wai
|
|
Sampled
Fishpond
|
River
water Sampling Stations
|
|
Parameters
|
Pond
2
|
Pond
13
|
Pond
19
|
Pond
56
|
Pond
59
|
Pond
62
|
W1
(Shan Pui River)
|
W2
(Tai River)
|
|
pH
|
6.2
|
7.7
|
9.3
|
6.9
|
8.9
|
7.0
|
7.8
|
7.5
|
|
Conductivity (uS/cm)
|
2510
|
1860
|
635
|
1640
|
1100
|
1100
|
16500
|
21500
|
|
D.O. (mg/L)
|
5.4
|
4.4
|
7.2
|
2.6
|
8.2
|
2.4
|
3.1
|
2.1
|
|
% Saturation of D.O. (%)
|
72.5
|
62.2
|
98.1
|
38.5
|
108
|
28.1
|
41.7
|
28.7
|
|
Temp. (oC)
|
31.3
|
31.0
|
30.4
|
30.7
|
32.5
|
30.5
|
30.0
|
29.0
|
|
Salinity (g/L)
|
1.1
|
0.5
|
0.3
|
0.7
|
0.5
|
0.5
|
8.8
|
11.9
|
|
Turbidity (NTU)
|
45.2
|
30.7
|
23.1
|
63.3
|
23.5
|
42.4
|
12.7
|
20.0
|
|
SS (mg/L)
|
72.7
|
57.0
|
28.3
|
93.7
|
47.0
|
49.7
|
32.3
|
26.3
|
|
Ammonia as N (mg/L)
|
0.03
|
0.03
|
0.04
|
2.96
|
0.07
|
0.39
|
5.4
|
2.8
|
|
Nitrate as N (mg/L)
|
<0.01
|
<0.01
|
<0.01
|
0.04
|
0.04
|
0.23
|
0.6
|
0.7
|
|
Nitrite+Nitrate as N (mg/L)
|
0.02
|
0.02
|
0.02
|
0.16
|
0.17
|
0.31
|
0.9
|
1.2
|
|
Total Kjeldahl Nitrogen as N (mg/L)
|
3.2
|
2.9
|
3.9
|
4.6
|
3.3
|
3.6
|
7.3
|
3.1
|
|
Total Nitrogen (mg/L)
|
3.2
|
2.9
|
3.9
|
4.8
|
3.5
|
3.9
|
8.2
|
4.3
|
|
Total Phosphorus (mg/L)
|
0.2
|
0.2
|
0.2
|
0.2
|
0.2
|
0.3
|
0.7
|
0.5
|
|
Reactive Phosphorus as P (mg/L)
|
0.03
|
0.03
|
0.02
|
0.02
|
0.03
|
0.02
|
0.6
|
0.4
|
|
BOD (mg/L)
|
10.0
|
8.7
|
14.3
|
5.3
|
9.0
|
4.7
|
3.0
|
<2
|
Note: All
measurements by ALS Technichem (HK) Pty Ltd. on 30 May 2002.
Table 6‑6 Results of Fishpond
Sediment Quality Survey at Fung Lok Wai
|
|
Sampled
Fishpond
|
|
Parameters
|
Pond
19
|
Pond
62
|
|
Heavy Metals
|
|
Silver (mg/ kg)
|
<1
|
<1
|
|
Arsenic (mg/ kg)
|
3.3
|
3.8
|
|
Cadmium (mg/ kg)
|
0.04
|
0.09
|
|
Chromium (mg/ kg)
|
9.5
|
37.4
|
|
Copper (mg/ kg)
|
4.2
|
17.4
|
|
Nickel (mg/ kg)
|
3.5
|
8.4
|
|
Lead (mg/ kg)
|
16.8
|
15.6
|
|
Zinc (mg/ kg)
|
21.5
|
71
|
|
Mercury (mg/ kg)
|
0.14
|
<0.05
|
|
Nutrients
|
|
Nitrite+Nitrate as N (mg/L)
|
0.15
|
0.11
|
|
Total Kjeldahl Nitrogen as N (mg/L)
|
552.7
|
978.6
|
|
Total Nitrogen (mg/L)
|
552.7
|
978.6
|
|
Total Phosphorus (mg/L)
|
186.17
|
759
|
|
Trace organics
|
|
Total PAHs (mg/L)
|
<0.5
|
<0.5
|
|
Total PCBs (mg/ kg)
|
<0.1
|
<0.1
|
6.3.23
The water sampling results are
summarised below:
·
The average pH values of the
samples are within WQO with the lowest and highest value of 6.2 and 9.3
recorded.
·
DO levels of the sampled
fishponds range from 2.6 to 8.2 mg/L with the mean value complying with the
Objective, and is higher than that of river water.
·
The sampled fishponds have high
SS levels and BOD5 value. This could be attributed to extensive fish farming
activities, limited water movement and air exchange at the fishponds.
·
The measured nutrients levels
(TKN, TN and TP) at the Tai River have similar levels as the fishponds but the
nutrients levels in Shan Pui River is higher than that of the Tai River.
6.3.24
Pond sediments were sampled for
analysis of heavy metal contents. A
comparison with the Dutch criteria indicates that the fishpond sediment is in
the uncontaminated category (A level). All measured heavy metal levels are
below the relevant Dutch criteria. Furthermore, with reference to the ETWB TCW
No. 34/2002 “Management of Dredged/ Excavated Sediment”, the sediment quality
are well within the Lower Chemical Exceedance Level (LCEL) and can be
classified as Category L
sediment to represent uncontaminated material. Based on the
pond sediment sampling results and the nature of the use associated with the
fishponds, it is not expected that the operation of the ponds will result in
any significant accumulation of heavy metal which could pose an environmental
impact on the surrounding water sensitive receivers. On the other hand, the
nutrient level of the samples is high as expected due to fish farming.
Summary of Existing Water and Sediment
Quality of the Water Sensitive Receivers
6.3.25
Shan Pui River
- The nutrient level of the flow in Shan Pui
River is especially high.
On the other hand, DO level is relatively low. Pollutants are mainly originated
from upstream catchment in Yuen Long area carried by Yuen Long Creek and Kam Tin
River though there is an
indication of slight improvement of river water quality. The unsewered villages
and livestock farms are expected to be the main pollution sources bringing
about nutrients, faecal organic wastes.
6.3.26
Tai River - Compared with Shan Pui River,
the water quality of Tai
River is generally
better. Still, there is a considerable level of nutrients.
6.3.27
Fishponds within the Site
and in the Surroundings - Owing to the nature of
use of the water ponds, there are high levels of nutrients found in both water
and sediments. For abandoned fishponds, the SS and nutrient level is slightly
lower in general but comparative to the actively managed ones.
6.3.28
Inner Deep Bay - Owing to the slow circulation of
water flow, pollutants tend to accumulate within this water body. Pollutants
brought from River Indus, Shenzhen River, Tin Shui Wai Nullah, Shan Pui River (Yuen Long Creek) includes
nutrients, faecal and organic wastes. Inner Deep Bay is subject to long-term problem of
nutrient enrichment, ammonia toxicity and bacterial contamination.
Existing
Activities
6.4.2
Other construction works and
livestock farms upstream of Yuen Long Creek and Tin Shui Wai Nullah generate
particulates, BOD5 and others, which result in poor water and
sediment quality in the Inner
Deep Bay.
Planned Activities during Construction Phase
6.4.3
Construction of the Project
includes the improvement works of an access road, site formation,
superstructure work and construction of other associated facilities for the
residential development, and establishment of the Wetland Nature Reserve (WNR).
6.4.4
Construction works involve
clearance of sheds, demolition of some existing fish pond bunds/ access paths,
ponds dredging followed by partial or complete pond filling, compaction and
piling works, road paving, foundation and superstructure works. The
establishment of the WNR will also involve creation of marshland and
re-profiling and landscaping of the ponds.
6.4.5
Pond filling will be divided
into a number of steps including draining of pond water, mud dredging and
filling of pond using public fill materials. Pond re-profiling, on the other
hand, involves temporary emptying of water ponds, dredging, removal and/or
reconstruction of bunds and refilling of the ponds, partial filling of mud for
formation of marsh land. Some of the bunds currently separating ponds will be lowered
and side cast to create shallow sloping margins to islands and / or shoals.
6.4.6
Particulates as well as
effluent, liquid spillage and the like will be generated on-site during
construction. Pollutants can runoff to nearby water bodies as non-point discharge
if not properly controlled.
Construction of Residential Development and Access Road - Dredging
and Pond Draining and Filling
6.4.7
The construction of the
residential portion and the WNR visitor centre of the Project requires ponds
draining, dredging and filling. The affected ponds are Pond No. 58, 59, 62, 25,
23 and 19 as per the preferred footprint for residential development and WNR
visitor centre.
6.4.8
After pond filling would be
foundation and superstructure works, and construction of other associated
facilities for the residential development and the WNR.
Construction and Establishment of WNR
6.4.9
There are currently 56
fishponds within the study site. Through the strategic removal of bunds these
will be consolidated into 21 larger ponds (See Figure 6‑9).
6.4.10 At selected locations, bund materials currently separating ponds
will be lowered and side cast to create shallow sloping margins to islands and
/ or shoals. The remaining bunds to be modified will be used to create islands.
Each island will rise at a slope 1:20 from the indicated waterline, based on
initial operating levels. The below water level slope will be as shallow as
feasible.
6.4.11 Each pond will be drained, dried and re-profiled on a 3 to 5-year cycles (please refer to Section 14 the Draft Habitat Creation and
Management Plan – Long-term Pond Management (Table
14‑13)) as typically currently carried out on fishponds.
During this process each pond bund will be re-profiled to create as shallow a
slope as feasible according to the properties of the bund material.
6.4.12 In addition, following re-profiling, further works will be
undertaken under the direction of the Site Conservation Manager to provide
variation in the shoreline profile along the typical waterline. This will be
carried out by using a backhoe to create indentations along the water line at
the Initial Operating Level by small-scale excavations and pressing down with
the back of the excavator bucket on the bund. Approximately 30% of the margins
of each pond should be worked in this way to create a ‘scalloped edge’ with
shallow shelves just below the Initial Operating Level (0.1 – 0.3m depth).
6.4.13 For flow control amongst ponds, the engineering requirements will
consist of installation of a series of adjustable sluices to interconnect the
ponds
6.4.14 All fishpond water will be obtained by direct rainfall and will be
retained and re-circulated during drain-down periods as necessary. One pond
will also be used in each year as a reservoir pond as a contingency measure to
ensure that pond water levels are kept within tolerance levels. No surface or
groundwater water supplies will be used for fishpond operations.
6.4.15 The establishment of WNR will involve the followings: -
·
Enlargement of some fishponds
for herons and egrets
·
Re-profiling of a no. of
selected pond bunds to enhance feeding of birds
·
Development of emergent
vegetation on selected pond margins for screening
·
Creation of areas of shallow
water and intermittently exposed muddy islands to enhance feeding and roosting
of birds
Planned Activities during Operational Phase
Residential Development and Access Road
6.4.16
The proposed residential
development will be located remote from the famous Mai Po Marshes to
minimise possible disturbances to this natural habitat.
6.4.17
All domestic wastewater will be
discharged to the public sewerage system. Water quality impact due to emergency
discharge from sewage pump house and sewer bursting are discussed in Section 8.8 of Section 8 Sewerage and Sewage Treatment
Implications.
6.4.18
Drainage system will be
provided for the formed and paved road/areas to drain stormwater runoff into
the storage pond next to the Marshland. Sand trap and oil interceptor will be
provided especially for car park and similar facilities, which would possibly
generate grease, oil and other pollutants.
Operation Of The Wetland Nature Reserve
6.4.19
The development of the Wetland
Nature Reserve provides another buffer zone for the famous Mai Po Marshes other than
the Hong Kong Wetland Park.
In fact, as it is relatively closer to the Mai Po Marshes as
compared with the Hong Kong
Wetland Park,
the proposed Wetland Nature Reserve will play a more important role in
minimising disturbance to the natural habitat in Mai Po.
6.4.20
Maintenance of fishponds and
wetland reservation areas is necessary during the operation of the proposed
development. A management plan is to be devised to determine a most
environmental friendly option including but not limited to details for feeding
of fisheries, set up of fencing and restriction from trespassing.
6.4.21
The water levels of the
fishponds inside the wetland nature reserve will be managed and controlled by
the Reserve Manager. During normal operation, the wetland nature reserve will
be self-contained and pond water will not be discharged to the surrounding.
Water will only be discharged when there is overflow. As the size of wetland
area is enhanced and the operating levels of the fishponds will be wisely
controlled and maintained at a relatively lower water levels comparing with the
water levels of conventional practices, the frequency of discharge upon
overflow will be less than existing situation.
6.4.22
The generation of fish excreta
and excessive feedstock are expected to be similar to the existing situation
but with slight improvement due to the devising of more environmental friendly
management plan including but not limited to careful selection of species and
control of fish population. Although existing fishponds of over 76ha will be redeveloped as Wetland Nature
Reserve, the hydrology remains the same. The overall impact due to discharge
upon overflow of the wetland area is expected to be slightly improved.
Operation of The Marshland
6.4.23
The Marshland complex will
comprise 3 distinct regions as follows: -
·
A relatively large area of
permanent marsh comprising a series of interconnected lakes and reed beds;
·
Seasonal marsh dominated by
tussocky grasses and sedges and temporary pools; and,
·
A storage pond.
6.4.24
The proposed Marshland complex
will be operated and maintained according to following principles:
·
The water supply will be from
the storage pond, which collects direct rainfall and run-off from the
residential development and catchments A and B (see Figure 6‑11).
·
Treated effluent will not be
discharged into the wetland and there will be no reliance on groundwater.
·
The marsh area will not flood
surrounding land and residential developments.
·
The lakes within the marsh area
will eventually discharge via Channel X or, during storm events, via Channel Y
(see Figure
6‑11) into the Tai
River outfall.
6.4.25
Water control structures will
be installed at the locations indicated in Figure
6‑10 to facilitate water management within the marsh
complex.
6.4.26
Water levels at the Permanent
Marsh Area will be allowed to fluctuate with seasonal patterns in rainfall but
will be kept within defined limits to prevent drying out or flooding of
susceptible vegetation through controlled release of water from the storage
pond. Water will also be released judiciously to reduce the rate at which
levels drop during the transition between wet and dry seasons.
6.4.27
At the Seasonable Marsh Area, a
segment of the western part of the marsh complex will be managed as seasonal
wetland receiving water from direct rainfall, and, during wet months, from the
permanent marsh area. When water exceeds a pre-determined depth within the
permanent marsh area water will flow into the seasonal marsh area via a sluice
placed between the two areas. Excess water with the seasonal marsh area will
gather at the northern end and exit via channel Y into the Tai River
outflow.
Natural/
Artificial Watercourse
6.5.1
There will be no alteration of
the any natural watercourse arising from implementation of the Project.
However, the Project will affect 3 on-site artificial drainage channels.
6.5.2
Channel X will be incorporated
into the proposed Marshland and Channel Z removed, as runoff will be collected
in the Storage Pond.
6.5.3
Channel Y will be unaltered and
be sluice controlled to allow orderly discharge of excess stormwater during
flooding periods.
Manmade
Fishponds
6.5.4
The Project occupies an area 80 ha in which the residential portion
at the southern edge will occupy about 4 ha.
This piece of land will be created by filling up a number of man-made fishponds
there. Assuming 100% concrete-paving, the residential portion will contribute
to an additional runoff due to change of catchment characteristics. This
additional runoff will be collected in the proposed Storage Ponds for
continuous discharge into the proposed marshland.
6.5.5
The surface runoff hydrographs
before and after the Project has been estimated using the SCS method. Only 4 ha of land located southwest of the
Site, which has changes in land use, were quantified.
6.5.6
The increase in volume of
runoff from the built area of the Project before and after implementation has
been calculated and tabulated as follows: -
Table 6‑7 Estimated Runoff After
Development
|
Return Period (Year)
|
Estimated
Volume of Runoff (m3)
|
|
Before
Development
|
After
Development
|
Increase
|
|
50
|
7,513
|
7,640
|
127
|
|
200
|
8,992
|
9,120
|
128
|
6.5.7
The increases in volume of
runoff are approximately 127 m3
and 128m3 for
50-year and 200- year return periods respectively. The increase in peak runoff
rates from the residential portion before and after implementation has also
been calculated and tabulated as follows: -
Table 6‑8 Estimated Peak Rate of
Runoff After Development
|
Return Period (Year)
|
Estimated
Volume of Runoff (m3)
|
|
Before
Development
|
After
Development
|
Increase
|
|
50
|
1.574
|
2.143
|
0.569
|
|
200
|
1.871
|
2.521
|
0.65
|
Artificial
Marshland
6.5.8
The Project will create 13.9 ha of artificial marshland to
enhance the ecological values of the WNR. This Marshland will alter the flow
regime by diverting the stormwater flowing in Channel Z through the Marshland.
The flow is however buffered by the Storage Ponds, which act as water reserve
for the Marshland during dry seasons.
Construction
Phase
6.6.1
Major potential sources of
water pollution may include the followings: -
·
Runoff and erosion from exposed
soil surface;
·
Runoff from stockpiles;
·
Fuels and lubricants from
machinery and trucks;
·
Liquid spillage such as
chemical, oil, diesel, and solvent;
·
General waste material;
·
Wastewater generated from
dewatering activities.
6.6.2
Water pollution due to site
facilities such as toilets could also be source of pollution if appropriate
measures are not implemented properly during construction in respect of storage
and discharge.
6.6.3
Additional impacts would arise
from runoff that is contaminated by chemical, oil, diesel, lubricant, and
solvent, etc. due to spillage or improper disposal. The implementation of Best
Management Practices (BMPs) by the contractor during the project period is
therefore important to control the release of these wastes. In addition,
wastewater could also be generated from other phases of works such as site
clearance, site preparation and completion of road construction.
Wetland Nature Reserve
6.6.4
Renovation of ponds may include
the demolition of existing bunds and boundary as well as construction of new
ones, partial filling and change of depth of the ponds. Draining of water is
necessary during construction. Renovation will be carried out in a phased
manner where water will be temporarily drained to other unaffected ponds and
will be drained back after renovation.
6.6.5
Construction of the WNR will
not alter the flow regime in the vicinity.
Residential
Development
6.6.6
Construction of the proposed
residential development involves:
·
Pond mud dredging
·
Pond filling
·
Compaction and foundation work
·
Superstructure construction
6.6.7
The strip of construction area
to be formed for residential development is located along the southern boundary
of the Subject Site remotely located from the Inner Deep Bay.
6.6.8
It is a general practice not to
dredge mud if possible to avoid any adverse impact due to increase in
particulate and re-exposure of any likely pollutants such as heavy metals. The
amount of mud that can be retained on-site depends upon the soil nature and the
method of construction of foundation. Yet, the possibility of the filling of
pond using public filling material, which will inevitably be carried out for
site formation, requires the draining of pond water to other places. The
drained water may need to be discharged to other fishponds within the Subject
Site. Compaction and foundation work involves piling and use of other powered
mechanical equipment. Runoff during construction will bring along particulate
to the water body including the existing fishponds.
6.6.9
Superstructure works are
typical of many building construction works, which would generate insignificant
degree of wastewater impact. If not properly controlled, the stormwater runoff
may bring along other pollutants so as to pollute the nearby water bodies
depending upon the topography.
Access Road Formation
6.6.10 The proposed alignment of the access road is to make use of existing
Fuk Shun Street
to connect the Development starting from the southern boundary of the Subject
Site to the Yuen Long Industrial Estate. The road improvement works comprise
the following construction stages:
·
Site clearance
·
Installation of utilities
required
·
Road foundation work and paving
of road
6.6.11 The proposed road works may pose water quality impact mainly due to
surface runoff containing suspended solids, which might be generated as a
result of excavation activities, earthworks. Apart from excavation, other
construction tasks including compaction and paving of roads would unlikely
generate considerable amount of dust.
Operational
Phase
General Runoff and
Sewage
6.6.12 Water for use in the WNR will be provided by direct rainfall
supplemented by run-off from the residential development and catchments A and B via a ditch running along the
southern border of the development area. Water will drain into the storage pond
at the eastern end of the proposed WNR.
6.6.13 The run-off from residential site will pass through traps to remove
oil and grease, and sand and gravel filters to reduce silt loads and
particulate organic matter prior to discharge into the ditch and the storage
pond. As runoff water from the catchments and development area will be stored
for long periods before entering the wetland area any remaining silt that is
present will be able to settle out in the water. This will further
significantly reduce pollutant levels (from the residential runoff and
catchments A and B). Regular maintenance, e.g. periodic de-silting will be
required.
6.6.14 Foul water, on the other hand, will be discharged to the public
sewer.
Discharge from WNR
6.6.15 The fishponds comprising the WNR will be interconnected with
adjustable sluices to allow the circulation of water to reduce the likelihood
of overflow upon heavy storm. In wet season, though unlikely, excess water will
be drained and discharged to the Tai
River under the
management of conservation manager. This would not be frequent and depends on
the intensity of rain.
General
·
Areas of ecological or
conservation values including marine conservation areas, existing or gazetted
proposed marine parks and marine reserves, sites of special scientific interest
(SSSI), existing or gazetted proposed country parks and special areas, wetlands,
mangroves and important freshwater habitats;
·
Areas for abstraction of water
for potable water supply;
·
Water abstraction for
irrigation and aquaculture;
·
Fish spawning grounds, fish
culture zones, shellfish harvesting/culture site and brackish/freshwater
fishponds;
·
Beaches and other recreational
areas;
·
Water abstraction for cooling,
flushing and other industrial purposes;
·
Areas for navigation/shipping
including typhoon shelters, marinas and boat parks
6.7.2
Criteria of relevance to this
Project include only point 1, 3 and 4. Water sensitive uses of these kinds are
described as follows: -
SSSI
6.7.3
There are 4 SSSIs existing in
the Deep Bay WCZ, viz.: -
·
Inner Deep Bay SSSI
·
Mai Po Marshes SSSI
·
Tsim Bei Tsui SSSI
o
Located next to the Tsim Bei
Tsui Sub-divisional police station, it comprises mainly a mature mangrove
community, which provides the only known habitat in Hong
Kong for the large mangrove pulmonate snail.
·
Tsim Bei Tsui Egretry
6.7.4
All of the 4 SSSIs are situated
downstream of the FLW Site which could be directly or indirectly affected by
its effluents and runoff.
Wetlands, Mangroves and
Important Freshwater Habitats
6.7.5
The existing wetland area (i.e.
the Inner Deep Bay SSSI) to the north of the Subject Site fronting Inner Deep
Bay is separated from the
Site by a number of fishponds. Water draining from the Tai River
and the San Pui River sustain an estuary, which is rich in important freshwater
habitats including mangroves near the river mouths. Runoff from the Subject
Site could indirectly affect these sensitive areas.
Water Abstraction for
Irrigation and Aquaculture
6.7.6
As agricultural activities have
already ceased for a long time in areas surrounding and downstream of the
Subject Site, it is unlikely that water will be abstracted for irrigation.
However, some of the existing fishponds outside the Subject Site could still be
practicing fish farming and thus relies on occasional abstraction of water from
the rivers.
Existing Freshwater
Fishponds
6.7.7
There are a number of existing,
actively managed fishponds situated to the north of the Subject Site, which
could be affected by runoff from the Project during a heavy rainstorm.
Hong Kong Wetland
Park
6.7.8
The Hong Kong Wetland Park
(HKWP) has recently been completed.
6.7.9
It is obvious from the existing
hydrology and flow regime that the Hong Kong
Wetland Park
and the Subject Site are separated by the Tai River
and share no common catchment. Runoff from within the Subject Site, either from
point or non-point source, should not in any way get into HKWP directly.
6.7.10
The Hong Kong Wetland
Park is therefore not
regarded as water sensitive receiver in respect of impact attributed by the
Subject Site.
Water Quality
Objectives
6.8.1
The Water Pollution Control
Ordinance (WPCO) (Cap. 358) enacted in 1980 is the principal legislation
controlling water quality in Hong Kong.
Under the WPCO, Hong Kong waters are
classified into 10 Water Control Zones (WCZ). Statutory Water Quality
Objectives (WQOs) are specified for each WCZ.
The WQOs for any particular waters, as defined in the WPCO, shall be the
quality, which should be achieved and maintained in order to promote
conservation and best use of those waters in the public interest. The Subject Site is situated within the
catchment area of the Deep Bay WCZ. Table
6‑9 presents the WQOs for Deep Bay WCZ, which has been
adopted for the assessment.
Table 6‑9 Water Quality Objectives for Deep Bay WCZ
|
Parameter
|
Objective
|
|
Dissolved Oxygen (depth-average)
|
Not less than 4mg/L in 90% of the samples
|
|
Dissolved Oxygen (within 2m of bottom)
|
Not less than 2mg/L in 90% of the samples
|
|
Unionized Ammonia
|
Annual mean not exceeding 0.021mg/L
|
|
Total Inorganic Nitrogen
|
Annual mean depth average not to exceed
0.5mg/L and 0.7mg/L for Outer and Inner
Sub-zone respectively
|
|
E.coli
|
Annual geometric mean not exceeding
610/100mL in secondary contact recreational areas
|
|
Salinity
|
Change due to waste discharge not to exceed
10% of natural ambient level
|
|
Temperature
|
Change due to waste discharge not to exceed
2°C
|
|
Suspended
Solids
|
Waste discharge not to raise the natural
ambient level by 30% nor cause the accumulation of suspended solids which may
adversely affect aquatic communities
|
|
Toxicants
|
Not to be present at levels producing
significant toxic effect
|
Sediment Quality Criteria
6.8.2
With reference to the ETWB TCW
No. 34/2002 “Management of Dredged/ Excavated Sediment”, sediment quality can
be classified as Category L, M and H sediment to represent uncontaminated materials,
moderately contaminated materials and seriously contaminated materials
respectively.
Table 6‑10 Classification of Sediment
|
Category L :
|
Sediment with all contaminant levels not exceeding the LCEL
|
|
Category M :
|
Sediment with any one or more contaminant levels exceeding the LCEL
and none exceeding the UCEL
|
|
Category H :
|
Sediment with any one or more contaminant levels exceeding UCEL
|
6.8.3
The selected sediment quality
criteria for classification of sediment stated in ETWB TCW No. 34/2002 is given
in Table 6‑11 below: -
Table 6‑11 Sediment
Quality Criteria for the Classification of Sediment
|
Contaminants
|
Lower Chemical Exceedance Level (LCEL)
|
Upper Chemical Exceedance Level (UCEL)
|
|
Heavy
metals (mg/kg dry wt.):
|
|
|
|
Cadmium
(Cd)
|
1.5
|
4
|
|
Chromium
(Cr)
|
80
|
160
|
|
Copper
(Cu)
|
65
|
110
|
|
Lead
(Pb)
|
75
|
110
|
|
Mercury (Hg)
|
0.5
|
1
|
|
Nickel (Ni)
|
40
|
40
|
|
Organic-PAHs
(mg/kg
dry wt.)
|
|
|
|
Low
Molecular Weight PAHs
|
550
|
3160
|
|
High
Molecular Weight PAHs
|
1700
|
9600
|
|
Total
PCBs
|
23
|
180
|
6.8.4
The quality of sediment
generated from the Project has been evaluated against the criteria.
Other Hong Kong Legislation and
Requirements
6.8.5
Other Hong Kong legislation and
requirements relevant to the Study include the Water Pollution Control
(General) Regulations and the Water Pollution Control (Sewerage)
Regulations as well as Annexes 6 and 14 of the EIAO TM.
6.8.6
The Technical Memorandum on
“Standards for Effluent Discharged into Drainage and Sewerage Systems, Inland
and Coastal Waters” (TM-Effluents) issued under Section 21 of the WPCO defines
acceptable discharge limits of effluent to different types of receiving
waters. Under the Ordinance, any
discharge into the WCZ requires licensing and must comply with the terms and
conditions specified in the licence, except for domestic sewage discharged into
public foul sewers, and unpolluted water into stormwater drains and river
courses.
6.8.7
The Livestock Waste Control
Scheme (LWCS) under the Waste Pollution
Control Ordinance in 1994 is also to prevent further deterioration in water
quality as a result of livestock waste discharged into rivers.
6.8.8
For the Deep Bay WCZ, the
standards in Table 8 of the TM-Effluents also apply for discharge into the
coastal waters of Deep Bay WCZ.
Waters Under Stressed Conditions
6.8.9
According to Annex 6 of the
EIA-TM, a water body is considered stressed if the existing water quality is in
breach of or likely to breach the WQOs or that necessary to protect the
beneficial uses designated for that particular water body. A water body under
stress must adopt the following criteria:
·
Activity must not contribute
to, increase or perpetuate stressed conditions;
·
Activity must not retard
recovery of the water body if level of pollution from other sources decrease.
6.8.10 The Inner
Deep Bay
is considered under stressed conditions as water quality data did show
non-compliance with the WQOs.
Deep Bay “No Net Increase Requirement”
6.8.11
It requires that major developments within Deep Bay catchments and all new
developments in sensitive areas of the catchments do not increase existing
pollution loads by connecting the sewage system of the developments to the
public sewer system. If connection of the public sewer system is not feasible, the development should include properly designed sewage
treatment facilities to treat the wastewater generated to achieve no net
increase of pollution loads to Deep
Bay.
Baseline Impact
6.9.1
Without the proposed Project,
there are already pollution loadings to the Inner Deep Bay arising from various uses upstream
of this receiving water body.
6.9.2
As far as the Subject Site is
concerned, there will be uncontrolled overflow of fishpond water in the event
of heavy rainstorms leading to non-point discharge into the surrounding water
bodies, i.e. the Tai River, San Pui River and ultimately into the Inner Deep
Bay.
6.9.3
For actively managed ones,
excess water will be pumped out and discharged to the nearby drainage and river
channels to regulate water levels from time to time. Both abandoned and
actively managed fishponds will have either point or non-point discharge to the
nearby rivers during heavy rainstorms despite the difference in the ways they
are managed. This will lead to discharge of pond water of higher nutrient
levels into the Inner
Deep Bay.
6.9.4
By examining the changes of
evaporation and rainfall data of these areas with time, the frequency and
volume of discharge can be estimated accordingly.
6.9.5
Table 6‑12 shows
a summary of annual evaporation and rainfall data.
6.9.6
Figure 6‑12 shows the daily variation of water rainfall during a
10-year period from 1989 to 1998 inclusive.
Table
6‑12 Summary of Annual Evaporation and Rainfall (1989 to 1998)
|
Year
|
Evaporation (mm)
|
Rainfall (mm)
|
|
1989
|
1227
|
771
|
|
1990
|
1144.1
|
569
|
|
1991
|
1169.6
|
1009.5
|
|
1992
|
1126.6
|
1994
|
|
1993
|
1119.4
|
1581.5
|
|
1994
|
1053.2
|
2314
|
|
1995
|
1131.8
|
477
|
|
1996
|
1210.1
|
1010
|
|
1997
|
1109.3
|
1994
|
|
1998
|
1158.7
|
1616.5
|
6.9.7
The volume and frequency of
water discharge from water ponds for the baseline scenario (without this
Project) has been determined based on time series of rainfall data. The area of
the actively managed and abandoned ponds within the Site has been estimated to
be about 60 ha and 10 ha respectively.
6.9.8
The daily change in water level
of the ponds during the period from 1989 to 1998 has been calculated by taking
into account the daily evaporation and rainfall intensity. For actively managed
ponds, a minimum water level (about 700mm below the top level) is maintained which
resembles that in the real situation or else fish farming will be adversely
affected. On the other hand, the calculations have allowed the possibility for
the entire abandoned fishponds to dry up theoretically due to the lack of
control.
6.9.9
Figure 6‑13 shows the volume of water discharged from the water
ponds within the Site before the development determined based on the time
series calculation model. Discharge from actively managed fishponds has
dominated over 90% of overall volume. An average outflow volume of about 215,000 m3 per year
was estimated.
6.9.10
It has been found in the
previous section and Table
6‑5 that the water quality of the actively managedand
abandoned ponds are comparative. The quality of the discharged volume can
therefore be regarded as typical water quality of the fishponds if the Project
were not developed, but with comparatively higher SS, BOD5 and
nutrient levels.
Possible Impact during the
Construction of the Project
6.9.11
It has been proposed, as a
broad strategy, to carry out habitat enhancement works within the northern part
of the site before construction of the residential development commences in
order to mitigate the interim ecological impacts.
6.9.12
These pre-construction works,
involving enhancements to ponds in Sectors 1, 2 and 3 (Figure 12‑2) and the construction of the Marshland will be staged
to reduce disturbance. Whilst works are being undertaken in Sector 1, the
remaining ponds of the site (Sectors 2 and 3 and the future Marsh Habitat Area)
will be managed to improve their interim value for birds. Once works are
completed in Sectors 1, 2 and 3, the newly enhanced ponds will be managed
according to the new long-term regime outlined in Section 14 the Draft Habitat
Creation and Management Plan.
6.9.13
The first stage will involve
enhancement works in the 13 existing ponds located within Sector 1 (Figure 12‑2). Once these works are complete then work can
commence on ponds within Sector 2. On completion of enhancement works in
Sectors 1 and 2 works can commence on construction of the Marshland. Once the
main structure of the marsh is formed work can commence on Sector 3. Following
enhancement fishponds will be managed under the modified regime outlined in the
Habitat Creation and Management Plan.
6.9.14
The major construction works
involved in pond enhancement relate to the removal of bunds between adjoining
ponds. To minimise disturbance to the rest of the site it is proposed that
enhancement works are conducted on one pair of ponds at a time. Pond water will
be drained to other neighbouring ponds for temporary storage.
6.9.15
The work sequence/ program
given in Table
2‑2 show the time periods, start and completion dates for
these actions. It is obvious from the program that the construction of the WNR
will be carried out during the dry seasons. Draining of pond water would affect
a handful of ponds for each Sector, the freeboard available in the neighbouring
ponds should be able to accommodate this temporary transfer of pond water
without the need for off-site discharge to nearby water bodies.
6.9.16
When the Marshland is worked
on, water will have to drain from a number of ponds with a total area of about 14 ha. Together with 4 ha of ponds that have to be filled for the
proposed residential development, there will be a total of 18 ha of ponds that have to be emptied.
6.9.17
A simple calculation can
demonstrated that this amount of water will be accommodated in the rest of
ponds to their north with a total pond area of 62 ha. This will translate into an increase of water
depths in these ponds by 30% during the dry seasons. Given an average depth of 2m and 1m of freeboard, the increase would be in the order of
0.6m of water without
overflowing.
6.9.18
Other than this issue, surface
runoff will be minimal in the construction phase, as most of the works will be
carried out during dry season. Moreover, temporary drains, sedimentation basin,
sand trap and similar facilities will be provided to ensure that the finally
discharge water quality will comply with relevant criteria.
Possible Impact during the
Operation of the Project
6.9.19
Foul water will be discharged
to the public sewers and should present no problem. The discharge requirement
of the Project and the capacity of the existing sewerage system have been
evaluated later chapter.
6.9.20
Surface runoff from the
proposed residential development and the associated access roads will be
drained to sand trap, oil interceptors and similar facilities to remove
possible pollutants prior to discharge.
6.9.21
Fishponds in the WNR will be
self-contained. During normal operation, under the management of conservation
manager, pond water will only be transferred within the WNR and the likelihood
of pond water discharge will be minimal. Pond water level will be regulated
between 1.2m and 1.9m above the bottom level. Maintenance work
will be carried out in a more frequent manner to remove pollutants in sediments
so as to reduce the nutrient levels.
6.9.22
It has been estimated that the
quality of pond water will be improved through the use of reed bed system in
marshland and intrinsically better water quality of fishpond due to better
management and less intensive fish culture.
Summary of Impact due to
the Project
6.9.23
Through transferring the pond
water within the subject site, the need of discharging pond water into the
surrounding water bodies during the construction of the Project can be
minimized. The operation of the Project shows a positive gain due to reduced
outflow and improved water quality and can compensate for any loss in a long
run.
6.9.24
Water will be discharged to the
two rivers nearby and eventually to the Inner Deep Bay under the supervision of the
conservation manager if considered necessary, for instance during or after
rainstorm. Pollutants, if exist during discharge, will be diluted and settled
before discharging to the marine environment.
There will be little influence to other areas such as the Hong Kong Wetland Park,
SSSI and wetland.
6.9.25
In fact, it is believed that
the quality of the discharge will be better than that of the baseline situation
as well as the upstream water quality.
Possible Cumulative Impact
6.9.26 The construction of Hong
Kong Wetland Park has been completed. Moreover, the
preliminary environmental review for the Hong Kong Wetland
Park has substantiated
that no significant water quality impact is anticipated during the operational
phase. There will be no cumulative impact contributed from the Hong Kong Wetland Park.
Construction Phase
6.10.1 Control of potential water quality impact arising from the
construction works shall be effected based on the following principles:
·
Minimisation of runoff;
·
Prevention or minimisation of
the likelihood of the identified pollutants being in contact with rainfall or
runoff; and
·
Measures to abate pollutants in
the stormwater runoff.
6.10.2 One measure to minimise runoff and pollutant is to have the
foundation and WNR construction works carried out during the dry seasons only
(i.e. from December to April
of the next year). During the dry seasons, the fishponds will have maximum
spare capacity to allow temporary storage of pond water during re-profiling of
the WNR so as to avoid the discharge of pond water. The Contractor should make
best use of existing ponds for the purpose of temporary storage during bunds
removal and realignment upon the construction of WNR. In addition, stormwater
runoff will be reduced to minimum.
6.10.3 Besides, the Best Management Practices (BMPs) will be implemented in
controlling water pollution during the construction phase. The guidelines for
handling and disposal of construction site discharges as detailed in EPD’s
ProPECC Note PN1/94 “Construction Site Drainage” will be followed. The water
pollution control measures that are considered most relevant to this study are
listed below which should be implemented by the contractor during the execution
of the site formation and road works, where practicable:
Runoff from Construction
Site
·
High loading of suspended
solids (SS) in construction site runoff shall be prevented through proper site
management by the contractor;
·
The boundary of critical work
areas shall be surrounded by ditches or embankment. Accidental release of soil or refuse into the
adjoining land should be prevented by the provision of site hoarding or earth
bunds, etc. at the site boundary. These
facilities should be constructed in advance of site formation works and
roadworks;
·
Consideration should be given
to plan construction activities to allow the use of natural topography of the
site as a barrier to minimise uncontrolled non-point source discharge of
construction site runoff;
·
Temporary ditches, earth bunds
should be provided to facilitate directed and controlled discharge of runoff
into storm drains via sand/ silt removal facilities such as sand traps, silt
traps and sediment retention basin. Oil
and grease removal facilities should also be provided where appropriate, for
example, in area near plant workshop/ maintenance areas;
·
Sand and silt removal
facilities, channels and manholes should be maintained and the deposited silt
and grit should be removed regularly by the contractor, and at the onset of and
after each rainstorm to ensure that these facilities area functioning properly;
·
Slope exposure should be
minimised where practicable especially during the wet season. Exposed soil surfaces should be protected
from rainfall through covering temporarily exposed slope surfaces or stockpiles
with tarpaulin or the like;
·
Access roads should be
protected by crushed rock, gravel or other granular materials to minimise
discharge of contaminated runoff;
·
Slow down water run-off flowing
across exposed soil surfaces;
·
Plant workshop/ maintenance
areas should be bunded and constructed on a hard standing. Sediment traps and oil interceptors should be
provided at appropriate locations;
·
Manholes (including newly
constructed ones) should be adequately covered or temporarily sealed so as to
prevent silt, construction materials or debris from getting into the drainage
system;
·
Construction works should be
programmed to minimise soil excavation works where practicable during rainy
conditions;
·
Chemical stores should be
contained (bunded) to prevent any spills from contact with water bodies. All fuel tanks and/ or storage areas should
provided with locks and be sited on hard surface;
·
Chemical waste arising from the
site should be properly stored, handled, treated and disposed of in compliance
with the requirements stipulated under the Waste Disposal (Chemical Waste)
(General) Regulation;
·
Drainage facilities must be
adequate for the controlled release of storm flows.
·
Dredged materials requiring
temporary storage on-site (for filling of marshland afterwards) should be
securely stored and covered, if possible. Dried up mud materials can then be
used for marshland formation.
Wastewater from
Construction Site
·
Sewage generated from the
construction workforce should be contained in chemical toilets before
connection to public foul sewer can be provided. Chemical toilets should be provided at a
minimum rate of about 1 per 50 workers. The facility should be serviced and
cleaned by a specialist contractor at regular intervals;
·
Foul water from canteens should
also be contained by chemical toilets before connection to public foul sewer
can be provided;
·
Vehicle wheel washing
facilities should be provided at the site exit such that mud, debris, etc.
deposited onto the vehicle wheels or body can be washed off before the vehicles
are leaving the site area;
·
Section of the road between the
wheel washing bay and the public road should be paved with backfill to reduce
vehicle tracking of soil and to prevent site run-off from entering public road
drains;
·
Bentonite slurries used in
diaphragm wall and bore-pile construction, etc. should be reconditioned and
reused as far as practicable. Spent
bentonite should be kept in a separate slurry collection system for disposal at
a marine spoil grounds subject to obtaining a marine dumping licence from
EPD. If used bentonite slurry is to be
disposed of through public drainage system, it should be treated to meet the
respective applicable effluent standards for discharges into sewers, storm
drains or the receiving waters.
Oils and Solvents
·
Spillage of fuel oils or other
polluting fluids should be prevented at source.
It is recommended that all stocks should be stored inside proper
containers and sited on sealed areas, preferably surrounded by bunds.
Draining of Fishpond
Water
·
Through transferring the pond
water within the subject site, the need of discharging pond water into the
surrounding water bodies during the construction of the Project can be
minimized.
·
Any draining of fishpond water
should be handled with prudence. Through the implemenation of EM&A
programme and supervision of the conservation manager, the water quality should
be checked to ensure that relevant water quality criteria can be complied with
and the water quality of the sensitive receivers nearby as identified in the
Section 6.3 of this chapter would not be further deteriorated.
·
Sedimentation tanks should be
set up at the construction site so that water to be discharged can be retained
for sedimentation if any discharging activity is considered necessary.
6.10.4 Given the proposition of all the effective mitigation measures
above, an environmental monitoring and audit programme should be devised in
order to ensure the proper implementation of the recommended measures and
provide a proactive system to rectify any problem at once before the situation
gets worse.
Operational Phase
Residential Development
and Access Road
6.10.5 All domestic sewage generated will be discharged to the public
sewerage. The drainage system will be designed to avoid any case of flooding
based on the 1 in 50 years
scenario with provision of treatment facilities including sand traps and oil
interceptors. Temporary buffer containers should be provided to retain
wastewater in case emergency discharge from sewage pump houses and sewer
bursting discharge occur as a contingency measure.
6.10.6 Regular cleaning and sweeping of the access road and other paved
areas are suggested so as to minimise exposure of pollutants to stormwater.
Stormwater gullies and ditches provided along the access road and among the
residential development will be regularly inspected.
6.10.7 Planter strips are provided along the access road and around the
residential development where practicable. In the event of emergency (e.g. car
accident) where there is a major spillage of oil, chemical or fuel, dispersants
or fire fighting foam, etc., a system of contaminant bunding is recommended as
far as practicable.
Wetland Nature Reserve
6.10.8 Best management practice will be adopted for the maintenance of the
wetland and fishpond areas. Regular maintenance of fishponds will be exercised
to remove excessive nutrients. Fish species will be carefully selected and the
quantity will be controlled to avoid excessive fish farming as usually happened
before the development of the Project.
6.10.9 A Wetland Nature Reserve management plan has been devised. No
application of herbicides, or pesticides is considered necessary.
Re-circulation pumping system will be provided for circulation of water between
ponds and in turn to reduce the likelihood of overflowing of ponds due to even
distribution of water volume.
6.10.10 Fishponds in the WNR will be self-contained. During normal
operation, under the management of conservation manager, pond water will only
be transferred within the WNR and the likelihood of pond water discharge will
be minimal.
6.10.11 The temporary storage of water at the storage pond can allow
sedimentation and removal of pollutants before discharge. It is particularly
useful prior to wet season as cleaner water will be discharged to allow spare
capacity for rainstorm.
6.10.12 The way to avoid overflow by intentional discharge upon the water
quality, for example, is also recommended. Reed bed and alike can be provided
in the marshland area to reduce nutrient discharge.
6.11.1
It is considered that the
provision of the best practicable measures recommended above during the
construction and operational phases should be effective to reduce the water
quality impacts on receiving water bodies.
Increase in pollutant load of Tai
River, Shan Pui River and Deep Bay WCZ due to the
discharges of runoff from the Subject Site including that arising from the
residential development, the access road and the Wetland Nature Reserve is
considered insignificant and alteration of the overall water quality is not
anticipated.
6.11.2
There could however be
non-point runoff during a heavy storm when all fishponds in the area overflow
to the nearby water bodies. This is considered a natural process and occurred
in the past even the Project was not developed. In such case, the diluted pond
water that gets into the Inner Deep Bay should unlikely to present a pollution
source exceeding the assimilation capacity of the water body as the water
quality would meet the WQOs.
6.11.3
Given the remoteness of the Hong Kong Wetland Park, the SSSIs and wetland along the coast, they should unlikely be
impacted during both construction and operation of the Project.
7.1.1
This section presents an
assessment on the potential problem of biogas in accordance with the
requirements given in Clause 3.5.3 of the EIA
Study Brief.
7.1.2
To create solid ground for the
proposed residential portion, ponds at the southwestern boundary of the Site
will have to be reclaimed. Top soils will be dredged from each fishpond and
filled with fill materials (e.g. marine sand or recycled C&D materials).
The dredged topsoil will be re-used on-site for the establishment of WNR.
7.1.3
Biogas comprises mainly of
methane and carbon dioxide and is generated as a result of anaerobic
degradation of organic matters buried under reclaimed land. The potential risk
would be migration of methane and carbon dioxide, which are flammable and
asphyxiating.
7.2.1
As it is impossible to measure
the rates of biogas emission at this stage from the organic sediment within the
reclaimed area, the biogas generation has therefore been estimated from the
proposed reclaimed areas based on a stoichiometric analysis.
7.2.2
The Total Organic Carbon (TOC)
and sediment oxygen demand (SOD) can be used to estimate the methane generating
potential of the sediment at the reclaimed areas.
7.2.3
SOD values are therefore used
to calculate the total biodegradable organic carbons in the sediment. SOD20days
has been analysed to estimate the “ultimate SOD” for estimation of biogas
generation.
7.3.1
Ponds dredging and filling will
be concentrated at the southwestern boundary of the Site where the residential
development is planned.
7.3.2
To enable a biogas assessment
be carried out, sediments were sampled at fishponds within the proposed
residential area where some pond mud could be to be left in place. Sediment
samples were collected at Pond no.19 and no. 62 as shown in Figure 7‑1 by a HOKLAS accredited laboratory in May 2002 for
analysis of Total Organic Carbon (TOC), Sediment Oxygen Demand (SOD20days) and
moisture content.
7.3.3
As it is envisaged that the
first 0.3m of
topsoil at the proposed residential area will be dredged before any filling
activities, sediments were therefore sampled at depths of 0.5m and 1m below pond water level to quantify the potential
biogas generation problem through appreciation of the TOC and SOD levels at the
surface layer.
7.3.4
Each sample weighs about 0.5g. The results of analysis are
presented in Table 7‑1 below.
Table
7‑1 Sampling Locations and
Levels of Total Organic Carbon (TOC) and Sediment Oxygen Demand (SOD)
|
Location
|
Sample Depth (m)
|
Moisture
(% w/w)
|
TOC
(% dry wt)
|
SOD 20days
(mg/kg)
|
|
Pond 19-1
|
1.0
|
21.6
|
0.69
|
2644
|
|
Pond 19-2
|
1.0
|
34.9
|
0.69
|
3372
|
|
Pond 19-3
|
1.0
|
24.4
|
0.34
|
2826
|
|
Pond 19-4
|
0.5
|
32
|
0.76
|
3468
|
|
Pond 19-5
|
0.5
|
31.2
|
0.58
|
3021
|
|
Pond 19-6
|
0.5
|
21.7
|
0.46
|
1144
|
|
Pond 62-1
|
1.0
|
26.2
|
0.95
|
2955
|
|
Pond 62-2
|
1.0
|
34.4
|
1.13
|
4861
|
|
Pond 62-3
|
1.0
|
25.2
|
0.71
|
1862
|
|
Pond 62-4
|
0.5
|
44.3
|
1.11
|
1912
|
|
Pond 62-5
|
0.5
|
38.9
|
0.83
|
1197
|
|
Pond 62-6
|
0.5
|
35
|
1.06
|
2317
|
|
Average
|
-
|
30.8
|
0.78
|
2632
|
7.4.1
Though the issue of methane
risk is not a requirement in the TM on EIA Process and there is no primary
legislation in Hong Kong covering hazards to developments caused by methane
gas, there is however certain relevant guidelines that can be referenced to
assess its safe rates.
7.4.2
The process adopted for
estimation of safe rates of biogas emission for filled land over sediment left in-situ
is similar to estimating safe emission rates of landfill gas when deciding
whether or not an old landfill site can be regarded as being sufficiently
stabilised without poses any danger. The assessment of a safe rate of landfill
gas emission is necessary for determining when a site no longer needs to be
monitored and when it can be used for unrestricted development. The assumption
made is that any type of building could be safely constructed on top of the
landfill and therefore required the adoption of a universally applicable safe
rate of methane emission.
EPD’s Landfill Gas Hazard Guidance Note
7.4.3
There is no primary legislation
in Hong Kong covering hazards to development
caused by landfill gas or methane gas generated from organic deposits. The most
relevant guidance is the guideline, “Landfill
Gas Hazard Guidance Note” issued by the Environmental Protection Department
(EPD). The guidance note recommends that methane gas should be monitored
periodically in all excavations, manholes and chambers and any confined spaces
during construction. No works and no entry to the excavation areas or confined
spaces should be allowed and the personnel on-site should be evacuated if the
methane concentration measured during the monitoring exceeds 20% lower
explosive limit (LEL) (or 1.0% gas).
Maximum “safe” rate of gas emission based on the UK Department of the Environment’s
Waste Management Paper No. 26A:
Landfill Completion
7.4.4
The UK Department of the
Environment Waste Management Paper No. 26A on Landfill Completion recommends a maximum
acceptable rate of methane ingress into a building constructed on a disused
landfill site. It states that methane emission rates from monitoring boreholes
should fall consistently below 0.015 m3
per hour. This criterion was developed to determine when monitoring of landfill
gas emissions at a restored landfill can be discontinued and when the site can
be used for unrestricted development. It is assumed that the most sensitive ‘at
risk’ room or void has a height of 2.5 m
and a very low rate of ventilation of 1 air change per week.
7.4.5
For residential development at
the built area of Fung Lok Wai, it is considered more conservative to adopt a
height of 1 m to represent
the void space (to allow for smaller void spaces such as utilities or services
ducts) and a ventilation rate of 1 air change per day (this is in line with
rates of natural ventilation for closed rooms). The maximum safe rate of
methane ingress was then defined as that at which it would take 1 day for the
methane concentration to reach 1% (v/v).
This is 20% of the lower explosive limit (LEL) for methane and provides
a safety factor of 5 to allow for variations in, for instance, rates of gas
emission across the area of the site or over time compared with those measured
at particular places and during the evaluation period.
7.4.6
The corresponding daily maximum
“safe” rate of methane gas emission per unit area is therefore calculated as
follows:
1.0
m x 0.01 d-1 (equivalent to m3 CH4 m-2d-1)
= 0.01 m3
CH4m-2d-1
= 10 litres CH4m-2 d-1
7.4.7
The criterion provides a
reasonable general guide for determining whether the rates of methane emission
pose an unacceptable risk to unrestricted development on a potential site.
7.5.1
The generation rate of biogas
depends on a number of parameters including concentrations and biodegradability
of the organic matters in the sediment, age of the reclamation, redox
potential, temperature, moisture content, presence of toxic matters which may
inhibit biological activities. These parameters may vary at different depths
and locations and their interactions are complex and difficult to predict. For the purpose of this preliminary
assessment, the potential methane risk will be assessed based on the
theoretical biogas production rate.
7.5.2
As learnt from several
anaerobic degradation projects, the formation of biogas under anaerobic
conditions can be described as a first
order degradation process. This
process is characterised by high gas generation rates at the early stage of the
process, followed by an exponential decrease over the course of time. Although
it is difficult to predict the extent of anaerobic conditions, the generation
of biogas can be estimated theoretically based on the available data on TOC and
the SOD.
7.5.3
At the residential development
area, the depth of topsoil dredged from each fishpond which are going to be
filled is about 0.3m.
Consequently, the methane generation potential of the sediment (fish pond mud)
to be left in place will be estimated based on the sediment layer in the depth
of about 0.3m to 2m. As such, the estimated quantity of
sediment at the built area is: -
Volume
of sediment left in-situ at built
area = 41,000m2
x (2 - 0.3) m = 69,700m3
7.5.4
SOD represents only a fraction
of the organic carbon present in the sediment. The total methane generation
potential calculated based on SOD results is usually much lower than that
calculated based on the TOC results because TOC is a measure of the total
organic carbon whereas some of it may not be biodegradable. SOD results, which
measure the biodegradable portion of the organic matters in the sediment,
provide a more realistic assessment comparing with those estimated using TOC
results.
7.5.5
However, as a prudent approach,
the estimation of methane generation potential for the proposed development
would be based on both TOC and SOD in the Study. It is because TOC results
represent the total organic content in the sediment, which in turn represent the
worst-case scenario of biogas generation, i.e. the maximum amount of biogas
that could be generated. On the other hand, SOD results may underestimate the
biogas generation potential due to limited test time. As such, SOD20days is
analysed instead of SOD5days to estimate the “ultimate SOD”.
Estimation of Methane Generation
Potential Based on TOC
7.5.6
It is assumed that 50% of the
gas produced from anaerobic degradation of organic matter of the sediment is
methane and the remainder is carbon dioxide. The degradation process can be
represented by the following equation:
2 C6H12O6 à 6 CH4
+ 6 CO2
7.5.7
On this basis, the mass of the
methane generated from unit mass of TOC can be calculated as follows:
12 C
à 6 CH4 + 6 CO2
12 x 12
= 144
6 x 16 = 96
7.5.8
The theoretical mass of methane
generated will equal to 0.67 times of the mass of TOC in the sediment.
7.5.9
The half-lives of anaerobic
degradation range from ½ to 5 years. In
considering that over 90% of the organic matter would have been degraded after
the first two years of development construction based on a half-life of ½ year,
this higher flux rate would not be significant for the future development. Besides, the methane flux (with a half-life
of ½ year) would also be reduced to a rate much lower than that of the peak
annual methane potential based on a half-life of 5 years after the first two
years of development construction.
7.5.10 Having said that, the decomposition rate of biodegradable organic
matter would be higher for a shorter half-life cycle of decay. So, in order to cover a reasonable range of
half-life cycles, the half-life cycles of 2 years and 5 years were considered
for estimation of total theoretical methane generation potential and daily
methane flux from the built area of the proposed development.
Estimation of
Methane Generation Potential Based on SOD
7.5.11
The amount of methane gas
produced per kg of SOD can be estimated as follows:
7.5.12
Assume that the starting
compound is glucose (C6H12O6), the
conversation of glucose to carbon dioxide and methane under anaerobic
conditions can be represented by the following balanced equation:
C6H12O6 à 3 CO2
+ 3 CH4
180 g 132 g 48 g
7.5.13
It should be noted that
although the glucose has been converted to carbon dioxide and methane, the
methane generation potential might be estimated by the oxygen requirement for
complete conversion of the glucose to carbon dioxide and water under aerobic
conditions.
7.5.14
The amount of methane formed
per kg of SOD can be represented in the following balanced equation for the
oxidation of glucose to carbon dioxide and water.
C6H12O6
+ 6 O2 à 6 CO2
+ 6 H2O
180 g 192 g
7.5.15
The SOD of glucose is (192/180)
kg, and 1 kg of
glucose yields (48/180) kg of methane, so that the ratio of the amount of
methane produced per kg of SOD is:
(kg CH4/kg SOD) = {(48/180)/(192/180)} =
0.25
7.5.16
Therefore, for each kg of SOD, 0.25 kg of methane will be formed.
7.5.17
The volume equivalent of the 0.25 kg methane produced from the equivalent
of 1 kg of SOD is:
Vol CH4
= (0.25 kg) * (103 g kg-1) * (1 mol/16 g) * (22.4 l mol-1) * (10-3 m3 l-1)
= 0.35 m3
CH4 (at standard conditions of temperature and pressure)
Therefore, 0.35 m3
of methane will be generated per kg of SOD converted.
7.5.18
Regular interval measurement of
dissolved oxygen up to 20 days would be done in the SOD test as such data can
be used to estimate the “ultimate SOD” which in turn is useful for estimation
of biogas generation. SOD will also include the nitrogenous oxygen demand (i.e.
the oxidation of nitrogen and ammonia), but in the estimation of the methane
generation potential it is assumed that the oxygen demand is entirely
carbonaceous demand. This represents a conservative approach and the actual
methane generation potential is expected to be lower.
7.5.19
With the average of SOD20days
levels of the sediment samples analysed, the theoretical methane generation
potential (in m3 CH4 /kg dry weight of sediment) will be:
= Average SOD20days (in mg
SOD kg-1 dry weight of sediment) x 10-6 kg
mg-1
x 0.35 m3CH4/kg SOD
7.5.20
The total theoretical methane
generation potential (m3 CH4) can be calculated with the following
information:
·
Volume of Sediment to be left
in-situ;
·
Assumed density of sediment
(i.e. 1500 kg m-3);
·
Average dry matter of the
filled area;
·
Mass of dry matter;
·
Total dry matter of sediment;
·
SOD20days in mg O2 kg-1 dry weight of sediment;
·
Total SOD in sediment
7.5.21
For the SOD level in the filled
pond is estimated to be 2,632 mg/kg, the total methane potential will be 658
mg/kg. On the other hand, under the assumption on sediment TOC of 0.78% of dry
matter and half is converted to methane, methane potential would be 5,226mg/kg
dry matter, which
was obtained from the methane generation potential
divided by the mass of dry matter. It implies that only 13% of TOC will be
biodegraded. Therefore, use of TOC to estimate methane potential provides an
overestimate of that potential. In addition, as some organic which are
degradable aerobically (which contribute to SOD) will not be degraded in
anaerobic conditions. As such, basing potential methane yield on SOD itself
already has the possibility on providing an over-estimate of methane potential.
Calculation of potential gas emissions
7.5.22
To be conservative, the peak
annual methane potential based on TOC with half-life cycle of 2 years and 5
years are therefore adopted for the calculations of potential methane gas
emission. The methane concentration at the surface layer of the built area of
Fung Lok Wai is estimated as illustrated in Table
7‑2 below. Upon
completion of pond filling, construction activities including compaction, site
investigation, and foundation construction will follow. Superstructure
construction will only commence after completion of these activities at about
1.5 years after completion of pond filling.
Confined space, if any, will only exist after the commencement of the
superstructure construction. Peak
methane generation potential is therefore estimated for the period after
commencement of the superstructure construction at about 1.5 years after
completion of pond filling. The methane
concentration and flux calculated based on this peak methane generation
potential are then compared with the guideline value (1%v/v) as stipulated in
EPD’s Landfill Gas Hazard Guidance Note and the UK methane hazard assessment
criteria (10 L/m2/d).
Table
7‑2 Calculation of Methane
Flux from the Fung Lok Wai Development
|
|
Half-life cycle of 2 years
|
Half-life cycle of 5 years
|
Remarks
|
|
Area (m2)
|
41000
|
41000
|
Total pond filling area
|
|
Depth of sediment left in-situ
|
1.7
|
1.7
|
0.3 to 2m below
ground (see S7.5.3)
|
|
Volume of sediment to be left
in-situ (m3)
|
69700
|
69700
|
= Area x Depth
|
|
Assumed density of sediment (kgm-3)
|
1500
|
1500
|
Assumed value
|
|
Moisture of sediment (% w/w)
|
30.8
|
30.8
|
Average value from Table 7-1
|
|
Dry matter (% w/w)
|
69.2
|
69.2
|
= 100% - moisture content
|
|
Mass of dry matter (kgm-3)
|
1038
|
1038
|
= Density of sediment x dry matter %
|
|
TOC (%)
|
0.78
|
0.78
|
Average value from Table 7-1
|
|
Mass of TOC (kgm-3)
|
8.10
|
8.10
|
= Mass of dry matter x TOC%
|
|
CH4 generation potential (kgm-3)
|
5.42
|
5.42
|
=0.67 x Mass of TOC (see S7.5.8)
|
|
Half life, t1/2 (yr)
|
2
|
5
|
Assumed value
|
|
Degradation constant, k
|
0.3466
|
0.1386
|
First-order degradation process:
ln[At]=-kt+ln[A0] and t1/2=ln[2]/k
where
A0 = total CH4 generation at t=0;
At = total CH4 generation at t=t;
k = degradation constant = ln(2)/t1/2;
t = time after commencement of degradation process;
t1/2 = half life in year
|
|
Total CH4 generation (kg) at year 0
(at completion of pond filling)
|
378094
|
378094
|
= CH4 generation potential x Volume of sediment = A0
|
|
Total CH4 generation (kg) at year 1.5
(at commencement of superstructure construction)
|
224816
|
307108
|
=e[(-k x 1.5) + ln(A0)] = A1.5
|
|
Total CH4 generation (kg) at year 2.5
(at 1 year after commencement of superstructure construction)
|
158969
|
267353
|
=e[(-k x 2.5) + ln(A0)] = A2.5
|
|
Total CH4 generation (kg) at year 3.5
(at 2 years after commencement of superstructure construction)
|
112408
|
232744
|
=e[(-k x 3.5) + ln(A0)] = A3.5
|
|
Peak annual CH4 potential after commencement of
superstructure construction (kg)
|
65847
|
39755
|
= A1.5 - A2.5;
the CH4 generation rate is decreasing as indicated by the
comparison that
(A2.5 - A3.5) < (A1.5 - A2.5)
|
|
Total potential CH4 flux (kgm-2 per year)
|
1.6060
|
0.9696
|
= Peak annual CH4 potential / Area
|
|
Total potential CH4 flux (L m-2 per year)
|
2248.4360
|
1357.4845
|
Unit conversion (=kgm-2 x 1000 / 16 x 22.4)
|
|
Total potential CH4 flux (L m-2 per day)
(assuming 13% of TOC biodegradable)
|
0.8008
|
0.4835
|
=L m-2 per year / 365 x 13%
|
|
Total potential CH4 flux (L m-2 per day)
(assuming 100% of TOC biodegradable)
|
6.1601
|
3.7191
|
=L m-2 per year / 365 x 100%
|
|
Potential CH4 concentration (% v/v) at the surface layer
(assuming 13% of TOC biodegradable)
|
0.0801
|
0.0483
|
For confined space as described in S7.4.5
= (L m-2 per day x 1m2)
/ (1000 L per
day at 1 air change per day) x 100%
|
|
Potential CH4 concentration (% v/v) at the surface layer
(assuming 100% of TOC biodegradable)
|
0.6160
|
0.3719
|
For confined space as described in S7.4.5
= (L m-2 per day x 1m2)
/ (1000 L per
day at 1 air change per day) x 100%
|
7.6.1
Assuming 13% of TOC
biodegradable, the predicted methane concentration based on a half-life cycle
of 2 years and 5 years are 0.080%v/v and 0.048%v/v respectively. The
concentrations are considered insignificant when comparing with the guideline
value of 1%v/v stipulated in EPD’s Landfill Gas Hazard Guidance Note.
7.6.2
Considering the highly unlikely
event of assuming 100% TOC biodegradable, the predicted methane concentration
based on a half-life cycle of 2 years and 5 years are 0.62%v/v and 0.37%v/v
respectively and are still within the guideline value of 1%v/v.
7.6.3
When taking the maximum “safe”
rate of gas emission derived from the Department of the Environment (1993),
Landfill Completion. Waste Management Paper No. 26A (10 L
m-2 per day) as the standard, with half-life cycle of 2 years and 5
years, assuming 13% of TOC biodegradable, the predicted methane emission levels
(0.80 and 0.48 L m-2
per day respectively) are only 8.0% and 4.8% of the guideline value
respectively. The provision of safety
factor is up to about 12.
7.6.4
Even under the conservative
estimation, the predicted methane emission based on half-life cycle of 2 years
and 5 years, assumption of 100% TOC biodegradable, are 6.16 and 3.72 L m-2 per day
respectively. They are still found to be
within the maximum “safe” rate.
7.6.5
It can be concluded that the
predicted methane concentrations are well within the relevant risk assessment
criterion and the leaving the pond mud in place is unlikely to generate any
potential biogas problem.
7.7.1
As it is unlikely that there
would be significant potential biogas problem, the following generic
precautionary measures are therefore recommended. No further monitoring and
mitigation measures are considered necessary.
Ventilation within “at risk” rooms
7.7.2
Rooms located at the
underground, such as utility (services) voids, transformer rooms and refuse
collection rooms, if any, may be susceptible to ingress of any biogas generated
on-site.
7.7.3
As an additional measure for
the protection of these rooms, mechanical ventilation may be provided to ensure
that if any gas enters the room it is dispersed and cannot accumulate to a
dangerous level. For particularly sensitive rooms, such as below ground
confined spaces which contain sources of ignition, forced ventilation may be
used in addition to the use of a low permeability membrane.
7.7.4
The most sensitive “at risk”
features of the proposed development is identified to be the car park located
at the basement area. The basement car park of the proposed development may be
susceptible to ingress and accumulation of biogas. It is therefore be necessary
to ensure the car park has adequate ventilation to prevent the accumulation of
any methane gas emissions to dangerous concentrations.
7.7.5
The basement car park
ventilation system should be designed to ensure that the car park air quality
guidelines given in ProPECC PN 2/96 Control of Air Pollution in Car Parks are
achieved. The minimum ventilation rate for a basement car park is 5 to 6 air
changes per hour in order to comply with the EPD requirement on carbon monoxide
concentrations within car parks. This ventilation rate is considered adequate
to disperse any biogas that might get into the car park.
7.7.6
Several ventilation systems
should be installed and evenly distributed within the basement car park. It is
also recommended that a back-up power supply shall be provided for the
ventilation system, so that certain designated exhaust systems will still
operate during power failure. Under normal circumstances, power failure should
be rectified within hours.
Precautions During Construction
7.7.7
Precautions may be required to
ensure that there is no risk due to the accumulation of gas within any
temporary structures, such as site offices, during construction works on the
filling area. It may be necessary, for example, to raise such structures
slightly off the ground so that any gas emitted from the ground beneath the
structure may disperse to atmosphere rather than entering the structure. A
minimum clear separation distance of 500mm, as measured from the highest point on the
ground surface to the underside of the lowest floor joist, is recommended in
the Landfill Gas Hazard Assessment Guidance Note, EPD (1997).
Precautions Prior to Entry of Below
Ground Services
7.7.8
Following construction,
accumulation of gas within any below ground services can pose a risk to the
staff of the utility companies. As a good working practice, prior to entry into
any confined space within the filled area (such as manholes, underground
culverts and utility casings), the gas atmosphere within the confined space
should be monitored for oxygen, methane and carbon dioxide. Personnel should be
made aware of the potential dangers and advised to take appropriate
precautions.
Precautions Prior to Entry of Below
Ground Services
7.7.9
The working practices should
follow the Landfill Gas Hazard Assessment Guidance Note, EPD (1997) guidelines
as follows:
·
Any chamber, manhole or culvert
that is large enough to permit access to personnel should be subject to entry
safety procedures. Such work in confined spaces is controlled by the Factories
and Industrial Undertakings (Confined Spaces) Regulations of the Factories and
Industrial Undertakings Ordinance. Following the Safety Guide to Working in
Confined Spaces ensures compliance the above regulations.
·
The entry or access point
should be clearly marked with a warning notice (in English and Chinese) which
states that there is the possibility of flammable and asphyxiating gases
accumulated within.
·
The warning notice should also
give the telephone number of an appropriate competent person who can advise on
the safety precautions to be followed before entry and during occupation of the
manhole.
·
Personnel should be made aware
of the dangers of entering confined spaces potentially containing hazardous
gases and, where appropriate, should be trained in the use of gas detection
equipment.
·
Prior to entry, the atmosphere
within the chamber should be checked for oxygen, methane and carbon dioxide
concentration. The chamber may then only be entered if oxygen is greater than
18% by volume, methane is less than 10% of the Lower Explosive Limit (LEL),
which is equivalent to 0.5% by volume (approximately), and carbon dioxide is
less than 0.5% by volume.
·
If either carbon dioxide or
methane is higher, or oxygen lower than the values given above, then entry to
the chamber should be prohibited and expert advice sought.
·
Even if conditions are safe for
entry, no worker should be permitted to enter the chamber without having
another worker present at the surface. The worker who enters the chamber should
wear an appropriate safety/ recovery harness and, preferably, should carry a
portable methane, carbon dioxide and oxygen meter.
7.7.10
In general, sufficient approved
resuscitation equipment, breathing apparatus and safety torches should be
available when work is being undertaken in confined spaces. Persons involved in
or supervising such work should be trained and practised in the use of such
equipment. A permit-to-work system for entry into confined spaces should be
developed by an appropriately qualified person and consistently employed.
7.8.1
As the residential footprint is
planned to build on the existing fishpond area, under anaerobic conditions, the
pond mud left in-situ may generate potential biogas risk.
7.8.2
With the TOC and SOD contents
of the pond mud in-situ sampled, the potential methane flux from the
Development based on half-life cycle of 2 years and 5 years are estimated. Even
under the extreme worse case scenario (100% of TOC is biodegradable), the
results are well below with the guideline value stipulated in EPD’s Landfill Gas
Hazard Guidance Note and the maximum “safe” rate of gas emission derived from
the Department of the Environment (1993), Landfill Completion. Waste
Management Paper No. 26A.
7.8.3
Generic gas precautionary
measures for the below ground structures of Development and precaution measures
to be taken prior to entry into any below ground services or confined space
within the Development are recommended.
7.8.4
With the incorporation and
implementation of the recommended precautionary measures. The potential biogas
hazard posed to the Development is considered to be minimal.
8.1.1
This section addresses the
sewerage and sewage treatment implications of the Project in accordance with
the criteria and guidelines given in Section 6.5 in Annex 14 of the TM.
8.1.2
The Project is located in an
area that is currently not sewered. As
per Section 6.5 in the
Annex 14 of the TM, the collection of wastewater discharged to a public sewer
is a preferred approach. A new sewerage system is therefore necessary for
disposal of sewage generated by the Project during its operational phase,
particularly when the Project is located within the boundary of Wetland
Conservation Area and is close to the Deep Bay.
8.1.3
Connection with existing
sewerage for centralised treatment is in line with the Deep Bay
“No Net Increase
Requirement” when compared to the option of
establishing a separate on-site sewage treatment plant. The feasibility, possible alignment,
potential impacts, design and requirements of the proposed sewerage system are
evaluated in this chapter.
8.2
Existing Sewage Disposal and
Treatment Facilities
Yuen Long Sewage Treatment Works (YL
STW)
8.2.1
The Project is not located in
any existing or committed sewered area. The Yuen Long Sewage Treatment Works (YLSTW)
is about 200m east of
the Project and is close to the Yuen Long Industrial Estate (YLIE).
8.2.2
The YLSTW is a conventional
activated sludge plant with removal of ammonia nitrogen. It provides primary
and secondary treatment with effluent discharged into the Shan
Pui River
at its downstream end and eventually to Deep Bay.
The present capacity of the plant is 70,000 m3/day DWF with a 4 DWF allowance
for preliminary and primary treatment and 3 DWF for secondary treatment.
8.2.3
The current DSD design
procedures give an equivalent capacity of 105,000 m3/day DWF for preliminary/ primary based on
treatment of all incoming flows and a peak factor with some allowance for
moderate storm water inflow of 2.67 DWF.
Ha Tsuen Pumping Station
8.2.4
The Ha Tsuen Pumping Station
transfers all received flows to the San Wai Sewage Treatment Works. The Stage 1
modification to the pumping station has been completed to increase the capacity
to 164,000 m3/day
DWF. Provision of land has been allowed for the Stage 2 expansion to attain 1.5
times the existing capacity.
San Wai Sewage Treatment Works (SWSTW)
8.2.5
The San Wai Sewage Treatment
Works (SWSTW) is located at about 5 km
southwest of the Project site. Stage 1 of the SWSTW is designed for DWF of 164,000 m3/day with
peak flow of 410,000m3/day
@2.5 DWF. The Government plans to upgrade the treatment level of SWSTW from
preliminary to Chemically Enhanced Primary Treatment plus disinfection with
further expansion of capacity to 246,000 m3/d.
8.2.6
Sewage is fed from the Ha Tsuen
Pumping Station, which serves the sub-regions in its locality. The SWSTW
provides preliminary treatment using screens and grit removal. Treated effluent
is discharged via a tunnel into the Urmston
Road in the Pearl River Estuary.
8.2.7
The effluent tunnel which
transfer treated effluent from SWSTW to Urmston Road is 3.0
m in diameter and 8.9 km
long. Transfer is by gravity. The average flow of the tunnel is designed to be 400,000 m3/day.
While the effluent outfall is 1.8 m
in diameter and 2.6 km long
discharging into the centre of the Urmston Road tidal channel in 22 metres of
water. The outfall is designed for an average flow of 294,000 m3/day.
Allowance has been made for a second outfall if required. The locations of the
existing sewerage systems near the Subject Site are illustrated in Figure 8‑1.
Tin Wah Road Sewage Pumping Station (TWRSPS)
8.3.1
The existing TWRSPS is
constructed to serve the Tin Shui Wai Reserve Zone Development (TSWRZ). It is
connected to the Ha Tsuen Pumping Station with a proposed twin rising main. The
pumping station has an ultimate capacity for a peak flow of 1,284 l/s.
Upgrading and Expansion of San Wai
Sewage Treatment Works and Expansion of Ha Tsuen Pumping Station
8.3.2
The “Upgrading and Expansion of
San Wai Sewage Treatment Works and Expansion of Ha Tsuen Pumping Station” is a
Designated Project under EIAO. The EIA report has been approved without
conditions on 12 May 2003.
8.3.3
According to the latest design
of DSD, the total sewage flow delivered by the Ha Tsuen Pumping Station will be
some 231,000 m3/day
DWF by 2016. After the Stage 2 expansion, there will be a spare capacity of 15,000 m3/day DWF
by 2016.
YLSTW Effluent Export or Upgrading of
YLSTW to Tertiary Treatment
8.3.4
As per the recommendations in
the Review of Yuen Long and Kam Tin Sewerage and Sewage Treatment Requirements
completed by EPD in 1999 (the Review), the YLSTW will maintain its secondary
treatment. There will be a pumping station and rising mains to transfer
effluent from the YLSTW to the disinfection system and effluent tunnel at San
Wai for discharge together with the effluent from San Wai Sewage Treatment
Works. It is estimated to have about 50,000 m3/d secondary effluent
to be discharged via the effluent pipelines.
8.3.5
The YLSTW effluent pipelines
form part of the “Yuen Long and Kam Tin Sewerage and Sewage Disposal (YLKTSSD)
Stage 2” elements.
It is named as Package 2A-1T
in the YLKTSSD Stage 2 Project and is a Designated Project under EIAO. A
Project Profile was submitted by the project proponent, Drainage Services
Department (DSD), on 9 August 200 and a Study Brief (No. PP-138/2001) was
issued by the Director of Environmental Protection on 21 September 2001. EIA
report was prepared by DSD in accordance with the Study Brief and approved
without condition on 17 June 2004.
8.3.6
Apart from the above effluent
export scheme, the Government is exploring an alternative scheme for upgrading
of YLSTW to tertriary treatment for the design flow of 50,000 m3/d and
local disposal. Under such scheming, no expansion of the existing treatment
works capacities of 70,000 m3/d
is needed.
8.3.7
In the information provided in
the Study Brief and Project Profile of the YLTSSD Stage 2, the items of Package
2A-1T include:
·
OP1-Pumping Station in the
north of YLSTW
·
OS1- Twin rising mains from
item OP1 to Tin Tze Road
in Tin Shui Wai; with alternative items: -
o
AP1- Pumping Station in the
north of YLSTW
o
AS1- Twin rising mains in the
northwestern side of YLSTW.
8.3.8
The locations of Package 2A-1T and its alternative elements are shown
in Figure
8‑2.
8.4.1
The Project has a design
population of about 8,490. Other schedules of the development are tabulated in Table 8‑1 below.
Table 8‑1 Development Schedule the Project
|
Total Site Area
(approximate)
|
800,000
m2
|
|
Proposed Plot Ratio
|
0.185
|
|
Proposed Total GFA
|
148,000
m2
|
|
Design Population
|
8,490
|
|
No. of Flats
|
Not more than 2,860
|
8.4.2
As per the recommendations in
the Sewerage Manual published by the Drainage Services Department in 1995, the
volume of sewage that will be generated from the proposed development has been
estimated at 3,153 m3/day (ADWF) based on a Global Unit Flow Factor
of 0.370 and a maximum design population of 8,490. The sewage will be of
domestic nature and no industrial wastewater discharges are expected.
8.5
Proposed Development,
Sewerage Options and Projection
8.5.1
With reference to the
recommendation and projection in the Review, different sewage disposal
strategies as shown in Figure
8‑4 are proposed for the Project: -
·
Strategy A (Eastern Option) – construct a new sewer to connect with the
YLSTW, laid under Fuk Shun Street and other local roads, and joining with the
existing sewerage;
·
Strategy B (Western Option) –
construct a new sewer to connect with the existing Tin Wah Road Sewage Pumping
Station. The sewage will then be conveyed to the Ha Tsuen Pumping Station and
eventually to the San Wai STW.
8.5.2
For Strategy A, two alignment
options are identified. The first option (herineafter referred to as Strategy
A1) is to construct a new 375mm
diameter sewer to connect with the YLSTW via Fuk Shun Street and local road next to Leon Court. The
sewer will be about 1,356m
long. Another option is to follow the same upstream routing of the proposed new
sewerage for the above Strategy A1 from the subject site to Fuk Shun Street but
connected to existing sewerage in Fuk Hi Street that would convey the sewage to
YLSTW via the existing sewerage in Wang Lee Street and Wang Lok Street
(hereinafter referred to as Strategy A2). The alignment of the two alternatives
of Strategy A (i.e. Strategy A1 and A2) are presented in Figure 8‑4.
8.5.3
For Strategy B, it is proposed
to provide a new 375 mm
diameter sewer with approximate length of 940m connecting the sewerage of the subject site and
the existing communal sewerage at junction of Tin Wah Road and Tin Tsz Road. Together with the other sewage collected from
Tin Shui Wai Reserve Zone and the Development Zone, the sewage from the subject
site will be delivered to the existing TWRSPS, and then via Ha Tsuen Pumping
Station to San Wai Sewage Treatment Works.
8.5.4
In view of the low-lying
condition of the development site, discharging sewage by gravity flow to nearby
pumping station or STW will not be feasible. Therefore the Project will be
provided with a sewage tank and a pump house for either sewage disposal
strategies outlined above. Details of the requirements of the proposed sewerage
system including the sewage pump house are presented in the Section 8.9.
Strategy A (Eastern Option)
8.6.1
The estimated sewage inflow to
YLSTW may exceed the existing 70,000 m3/d
by year 2011 under early planning. However, it will depend on the actual
development in the catchment and the sewage flow build-up due to the Yuen Long
Industrial Estate. The information provided by DSD illustrating the projected
total flow to YLSTW from 2000 to 2016 is presented in Figure 8‑5.
8.6.2
Actually, only about 15,000 m3/d
DWF of the raw sewage is discharged to YLSTW as at 2007. That is much less than
the original estimated ADWF of about 43,000 m3/d as indicated in the
above Figure 8-5. Such a phenomenon is caused by a sharp decline of wastewater
generating industry over the last few years. Industrial wastewater flows from
Yuen Long Industrial Estate (YLIE), which flows to the YLSTW will probably
remain at their current magnitude or even decline.
8.6.3
As discussed in the above
Section 8.3, different schemes proposed for the disposal of the treated
effluent from YLSTW being reviewed by the Government are both designed for the
DWF of just only 50,000 m3/db. It is thus found that the existing
YLSTW with the DWF capacity of 70,000 m3/d
would have spare capacity of about 20,000 m3/d that will be sufficient to
cater for the flow discharging from the subject site.
8.6.4
Having considered such spare
capacity, it is ascertained that the YLSTW is capable of catering for the
estimated residential sewage of 3,153 m3/d
from the Project.
8.6.5
There are existing sewers in Fuk Hi Street to
receive sewage from the village huts along Fuk Shun Street. The existing sewers
beneath Wang Lee Street
and Wang Lok Street
of the YLIE are built to divert the sewer generated from the YLIE and also the
catchment from Fuk Shun Street
to the YLSTW.
8.6.6
A Sewerage Impact Assessment
(SIA) has been carried out for Strategy A2 to confirm the feasibility and
possible impact of using the existing sewers under Fuk Hi Street, Wang Lee Street and Wang Lok Street for diverting sewage
generated by the Project to the YLSTW. Details of the SIA are presented in
Appendix 8-1.
Strategy B (Western
Option)
8.6.7
The SIA presented in Appendix
8-1 has studied the feasibility of Strategy B and possible impact on existing
sewerage system. .
8.6.8
The existing TWRSPS has an
ultimate capacity for a peak flow of 1,284 l/s i.e. 110,937.6 m3/day. The projected flow to the
TWRSPS is about 41,000 m3/day
(ADWF) which would be within the normal design tolerance of the pumping
station, as the additional flow is roughly equivalent to only 7.7% increase of
the current projected flow of 41,000 m3/day.
The pumping station is thus considered to have adequate capacity to absorb all
of the sewage discharge from the Project.
8.6.9
As shown in Figure A8-7 in Appendix 8-1 Sewerage Impact
Assessment, the pumping station with an ultimate capacity PWWF of 6.269 m3/s is
considered to have enough spare capacity to absorb the ultimate flows from the
Project and TSWRZ (i.e. PWWF 1.424 m3/s).
8.6.10
As Ha Tsuen Pumping Station and
San Wai STW are designed to cope with the discharge from TWRSPS, they should
have spare capacity to absorb the ultimate flows from the Project.
Strategy A
8.7.1
As a new sewer connecting the
pump house of the Project and YLSTW is to be built for its entire length for
Strategy A1, no upgrading of existing sewers are required for this sewerage
option. The new sewer will be laid beneath existing local roads, viz. the Fuk Shun Street and
the local road next to Leon Court.
The approximate length will be about 1,356m. Wayleave from the Government is required.
8.7.2
For Strategy A2, a new sewer
would have to be built to connect to the existing sewer under Fuk Hi Street for
discharging the sewage from the subject site to YLSTW direct. As evaluated in
the SIA presented in Appendix 8-1, no upgrading work on the downstream side of
the existing sewers is considered necessary.
8.7.3
It is estimated that 4 months
would be required for installing the new sewer under Strategy A. The
installation works will be carried out during the improvement works of the
access road.
8.7.4
By comparing size of the
proposed works and relevant impact on the public, Strategy A2 is preferable to
Strategy A1.
Strategy B
8.7.5
Strategy B requires laying of 940m new sewer beneath the planned/ existing
road at the western side of the subject site. Way-leave from the Government is
required.
8.7.6
It also requires to increase
the pipe delivery capacities in Tin
Wah Road by either upgrading the existing sewerage
system or laying an additional sewer. Table 7.3 of the Appendix 8-1 SIA shows
that all segments of sewage pipes under Tin Wah Road, except the section from
manhole s11121 to
s11125a, will
not have enough capacity to cope with projected ultimate design flow even
without the additional flows from the Project.
8.7.7
Upgrading of the sewage pipes
from manhole s11102 to
s11121 with length of 948.8m
is considered necessary to convey the flow from the Project to TWR pumping
station via the sewers under Tin
Wah Road. The size diameter of the proposed
upgraded pipes and the adequacy of sewerage network after upgrading the sewage
pipes are given in Table
8‑2.
Table 8‑2 Required Upgrading of the Sewerage Network Leading to the
TWR pumping Station
|
|
Length (m)
|
Level (out) (m)
|
Level (in) (m)
|
Diameter (m)
|
|
Sewage Pipe
(s11102>s11103)
|
42.0
|
5.98
|
5.77
|
0.600
|
|
Sewage Pipe
(s11103>s11107)
|
161.0
|
2.92
|
1.65
|
0.600
|
|
Sewage Pipe
(s11107>s10519)
|
235.2
|
1.57
|
-0.28
|
0.600
|
|
Sewage Pipe
(s10519>s11117)
|
241.1
|
-1.29
|
-1.78
|
0.900
|
|
Sewage Pipe
(s11117>s11121)
|
269.5
|
-1.95
|
-2.31
|
1.050
|
8.7.8
As an alternative to minimize
interruption to the operation of the existing sewerage, it is also feasible to
lay a new sewer alongside the existing one at Tin Wah Road to convey the flow.The proposed sewerage works at Tin Wah
Road will be programmed in such a way as to maintain the normal function of the
existing sewer and normal traffic on the road.
8.7.9
A period of 12 months would be
required for Strategy B in constructing new sewers. The time for traffic
diversion under each strategy has already been included. It will involve
increasing the size of the proposed public sewer. No modification on the design
of the TWR Pumping Station is necessary.
Construction Phase
8.8.1
The general possible
environmental impacts generated from the construction of the sewerage systems
and the proposed mitigation measures, regarding air, noise, water, waste
aspects, are presented in the relevant chapters. With the proposed mitigation
measures implemented, the environmental impacts posed by the construction
activities of sewage systems are anticipated to be insignificant.
Operational Phase
8.8.2
During the operational phase,
the on-site pump house required for either disposal strategies are expected to
cause insignificant environmental impacts in terms of air, noise and water
pollution during its operation.
8.8.3
Odour - the main odour
nuisances can be attributed to the wet wells/ retention tanks of the pump
house. As such, the pump house will be enclosed inside building structure
equipped with adequate odour control measures such as scrubber and activated
charcoal filter at the exhaust of the ventilation system. The vent will be
located away from air sensitive uses including the proposed development itself.
8.8.4
The noise level that could be
caused by the pump house during its operation phase has been addressed in
Section 5.7 about noise impact assessment and was found acceptable.
8.8.5
On the water pollution aspect,
the pump house will be entirely enclosed with adequate odour and noise control
measures. The on-site facilities will be provided with adequately sized raw
sewage retention tanks and necessary redundancy in the pump sets and stanby
generators to ensure uninterrupted operations in case of occasional failure.
8.8.6
In the unlikely event that all
these measures fail, the fallback will be to tanker away the sewage to the
nearest YLSTW so as to avoid overflowing and discharge of raw sewage to the
nearby sensitive ecological environment, e.g. the WCA or WBA of Deep Bay. The
discharge of untreated sewage will be prohibited and is likely to be part of
the licencing requirements.
The Preferred
Options
8.8.7
On technical feasibility, the
Strategies A1, A2 and B discussed in the foregoing paragraphs are all feasible.
8.8.8
On land matter, comparing
Strategies A1, A2 and B, Strategies A1 and A2 are better given its relatively
shorter wayleave (1,356m and 581m for laying new sewers under Strategy A1
and A2 respectively) with no upgrading of existing sewers required. The
required wayleave for Strategy B is about 2,266m (i.e. 940m for laying new sewers at the distance between the
subject site and Tin Wah Road
and approximate 1,327 m for upgrading of existing sewer or
new sewer in Tin Wah Road).
8.8.9
On construction complexity and
programme, Strategies A1 and A2 can obviously be completed within the shortest
period of time and with least disturbance to traffic.
8.8.10
The choice of sewage disposal
strategy remains open at this stage, subject to the decision and approval from
the Government in consideration of the sewerage proposals for the district.
Whilst Strategy A2 is considered preferable from implementation point of view,
Strategy A1, A2 and B are all environmentally acceptable and hence sewage
disposal is not considered an issue in this EIA.
Sewage Pump house
8.9.1
Design of the pump house will
follow the recommendations in “The hydraulic design of pump sumps and intakes”
by M. J. Prosser. The selection of equipment will comply with the followings:
·
Statutory ordinances or
regulations;
·
Relevant British Standards of
equivalent;
·
I.E.E. wiring regulations;
·
Local electricity supply
authority requirements;
·
Hong Kong SAR Government Fire
Services Department requirements; and
·
Hong Kong SAR Government
security requirements.
8.9.2
The selection of the number of
pump units for the pump house should be based on the following criteria:
·
Providing a standby capacity of
33% to 50%;
·
Maintaining a minimum velocity
of 0.6 m/s under all pumping
conditions; and
·
Keeping the retention time in
the wet well to a minimum and be less than 30 minutes.
8.9.3
Standby sewage pump and
generator will be provided in case of power failure. No emergency bypass will
be allowed to the surrounding ecologically sensitive areas.
8.9.4
The sewage pump house will be
located at the built area of the Development. Subject to the choice of sewerage
option and the final design of the MLP and the pump house, the sewage pump
house is tentatively proposed to be housed inside a concrete structure near the
car-park area for the visitors with openings at the southern side facing away
from any Noise Sensitive Receivers. It will be equipped with 2 duty and 1 standby
sewage pump to raise the sewage head by about 9m. Given its proven reliability and ease of
inspection and maintenance, electrically operated vertical spindle non-clog dry
well sewage pump will be used.
8.9.5
The pump house will comprise a
dry well, a divided wet sump, retention sumps and an intake channel. The
loading bay for cart-away of sludge and grit will be located within the pump
house building to facilitate odour control.
8.9.6
The pump house will be designed
for unattended operation with appropriate instrumentation and control systems.
Remote monitoring and alarms will be provided by a telemetry system if
necessary.
8.9.7
In accordance with Table 3 of
the Sewerage Manual, for the population of the development is less than 10,000,
the flow peaking factor (including Stormwater Allowance on ADWF) for the sewage
pump house is around 5.11. Based on the calculated sewage flows for the
Development, the proposed pump house is designed to have an ultimate capacity
for a peak flow 5.11 x ADWF i.e. 5.11 x 36.4 l/s = 186 l/s.
8.9.8
In order to minimise the chance
and duration of failure incidence of the pump house which may result in
emergency discharge, the following mitigation measures are proposed to be implemented: -
·
Twin rising mains will be
provided for the pump house to ensure the proposed sewage rising mains are
maintainable without the need to shut down and discharge untreated sewage into
the natural stream/drainage directly.
·
Standby pump will be made
available to facilitate the maintenance and repairing of equipments;
·
Back-up power supply will be
provided in the format of either ring main or automatic-operated emergency
generator with sufficient capacity to cope with the demand loading of the
essential plant equipment;
·
Overflow should not be allowed
to occur on a regular basis e.g. facilitating routine maintenance. In the unlikely event that all the above
measures fail, the fallback will be to tanker away the sewage to the nearest
YLSTW so as to avoid overflowing and discharge of raw sewage to the nearby
sensitive ecological environment
8.9.9
Piled foundation are
recommended and considered technically viable for the pump house as it does not
require removal of all relatively soft pond mud underneath which will result in
less disposal of spoil.
8.9.10
The exact details of the pump
house will be agreed with DSD, EPD and EMSD during the detailed design stage.
Sewers
8.9.11
All sewers will be sized for
the ultimate development at Fung Lok Wai. The design criteria of sewers and
manholes should follow the requirements in the Sewerage Manual published by
Drainage Services Department and Civil Engineering Manual Volume VI where
appropriate.
8.9.12
Manholes of depth will be
constructed to standard details shown in DSD Standard Drawings.
8.9.13
In accordance to the
requirements of the Sewerage Manual, manholes will be provided at:
·
Intersection of sewers;
·
Junction between different
size/gradient of sewers;
·
Location where the sewer
changes direction; and
·
On long straight lengths at the
following intervals:
|
Diameter of pipe size (mm)
|
Maximum intervals (m)
|
|
Smaller than
600
|
40
|
|
Between 600 –
1050
|
80
|
|
Larger than
1050
|
120
|
8.9.14
The maintenance and operation
requirements for the pump house, sewers and manholes will be the same as those
for similar installations elsewhere in the Territory and should therefore
follow normal procedures.
8.10.1
Taking into consideration the
existing and committed sewerage facilities in the vicinity of the Project, the
sewage disposal strategies A1, A2 and B have been investigated for the Project.
In broad terms, these strategies involve installing an on-site sewage pump
house within the Project site and providing a new sewer to discharge sewage to
the nearby sewage treatment work or pumping stations.
8.10.2
The three proposed strategies
are all considered technically feasible although this is subject to negotiation
and agreement with the relevant Government departments.
8.10.3
The selection of sewerage
options remains open at this stage, subject to the decision and approval from
the Government in consideration of the sewerage proposals for the district.
From implementation point of view, Strategy A2 is more preferable.
8.10.4
It is proposed that the project
proponent will be responsible for the construction and the upgrading
of the needed sewerage system and the connections with the agreement with DSD while the Government will take up the maintenance responsibility
after the project proponent hands over the sewers to the Government upon
completion.
9.1.1
This section identifies the
quantity, quality and timing of wastes arising as a result of construction and
operation of the Project. The waste management implications are evaluated and
assessed in accordance with the criteria and guidelines given in Annexes 7 and
15 of the EIAO TM. Clause 3.5.5 of the EIA Study
Brief sets out the scope and requirement of the assessment.
9.1.2
The appropriate disposal method
for each type of waste was identified. Opportunities for reducing construction
waste generation and maximizing re-use on-site were evaluated. The potential
impacts arising from handling, collection, and disposal of wastes and the
environmental mitigation measures required to mitigate these environmental
impacts were identified and recommended.
9.1.3
Due to the low-density nature
of the proposed residential development, the operation of the development will
generate limited amount of domestic wastes. The handling and disposal of this
small quantity of waste during the operational phase will follow the usual
approach of collection by refuse collection vehicles (RCV) as it is managed in
other parts of Hong Kong. This will therefore
unlikely to cause any significant environmental impact. The waste management
implication during the operation of the residential development is therefore
not evaluated in this EIA study.
9.2.1
The principle legislation
governing waste management in Hong Kong is the
Waste Disposal Ordinance (Cap. 354) (WDO), and its subsidiary regulations. The
Ordinance, enacted in 1980, generally encompasses all stages of waste
management, from place of arising to final disposal point of waste. The Waste Disposal (Chemical Waste) (General)
Regulation, enacted under the WDO in 1992, provides controls on all aspects of
chemical waste disposal, including storage, collection, transport, treatment and
final disposal.
9.2.2
In addition to the WDO and its
subsidiary regulation, the following legislation have some bearing on the
handling, treatment and disposal of wastes in Hong Kong,
viz.:
·
Dumping at Sea Ordinance
(1995);
·
Crown Land Ordinance
(Cap. 28);
·
Public Health and Municipal
Services Ordinance (Cap. 132) Public Cleansing and Prevention of Nuisances
(Urban Council) and (Regional Council) By-laws; and
·
Dangerous Goods Ordinance; and
·
Air Pollution Control (Open
Burning) Regulation.
9.2.3
There are also various
guidelines which are relevant to waste management in Hong
Kong:
·
Waste Disposal Plan for Hong Kong (December 1989), Planning, Environmental and
Lands Branch Government Secretariat;
·
New Disposal Arrangements for
Construction Waste (1992), Environmental Protection Department & Civil
Engineering Department;
·
Code of Practice on the
Packaging, Labelling and Storage of Chemical Wastes (1992), Environmental
Protection Department;
·
Works Branch Technical Circular
No. 12/2000, Fill Management;
·
Environment, Transport and Works Bureau Technical Circular (Works) No.
34/2002, Management of Dredged/Excavated Sediment;
·
Works Branch Technical Circular
No. 2/93, Public Dumps;
·
Work Branch Technical circular
No. 16/93, Wet Soil in Public Dumps;
·
Works Bureau Technical Circular
No. 5/98, On Site Sorting of Construction Waste on Demolition Sites;
·
Environment, Transport and Works Bureau Technical Circular (Works) No.
31/2004, Trip-ticket System for Disposal of
Construction and Demolition Material;
·
Works Bureau Technical Circular
No. 25/99, Incorporation of Information on Construction and Demolition Material
Management in Public Works Subcommittee Papers;
·
Works Bureau Technical Circular
No. 4/98, Use of Public Fill in Reclamation & Earth Filling Projects;
·
Works Bureau Technical Circular
No.19/2001, Metallic Site Hoardings and Signboards; and
9.3.1
With the waste generating
activities identified, wastes generated during the construction phase of the
project would likely comprise the following categories:
·
Construction and Demolition
Material (C&DM) from excavation works, including fishponds sediment and
bund materials from pond dredging activities;
·
Chemical waste from vehicle and
equipment maintenance activities;
·
General refuse from workforce
on-site.
9.3.2
The potential environmental
impact arising from the handling, storage, transport and disposal of these
different categories of waste and the recommended waste management and control
measures are described below.
Construction and Demolition Material
(C&DM)
General
9.3.3
The Fung Lok Wai site is
topographically flat, rural in character, and primarily occupied by fishponds.
Construction works required for the Project will unlikely result in generation
of a large quantity of C&DM as extensive excavation activities will not be
required.
9.3.4
Demolition material would be
generated from clearance of a small number of huts on-site. A “selective
demolition” approach should be adopted so that reusable material such as wood,
metal, and steel can be segregated for reuse or recycling as far as
practicable. Inert building debris such as concrete and brick can also be
reused on-site as lining or fill material. The remaining part comprising of
degradable waste should be properly disposed of at landfills.
9.3.5
Construction waste that could
be directly generated from construction activities and from surplus
construction material may include:
·
Surplus concrete or grouting
mixes;
·
Wood from formwork and
Materials and equipment wrappings, etc.
·
Damaged or contaminated
construction materials; and
·
Equipment and vehicle
maintenance parts;.
9.3.6
The generation of wastes from
these materials should be minimised as far as practicable through recovery,
reuse and/ or recycling. Construction
methods aim at minimizing construction and demolition waste will be used. External walls pre-fabricated in factories
and fitted with finishes, windows and glazings will be delivered to site and
installed floor by floor. This will
substantially reduce the amount of concreting on site. Metal formwork will also be used for all
in-situ concreting where necessary. This method of construction will basically
eliminate the use of timber formwork on site and thus reduce substantially
timber and concrete waste. Whenever practicable, the production of
construction waste due to over-ordering or as “side-products” of construction
activities should be minimised by the contractor through careful design,
planning, good site management, control of ordering procedures, segregation and
reuse of materials. These measures will
also assist the contractor in minimising costs associated with the construction
works.
9.3.7
Should construction site
hoarding be erected, metal fencing or building panels, which are more durable
than wooden panels, are recommended to be used as far as practicable. Opportunity shall also be sought to re-use any wooden
boards used in site fencing on-site or off-site. Concrete and masonry can be crushed and used
as fill material if practicable. On-site incineration of wooden waste is
prohibited.
9.3.8
Cross contamination of inert
C&DM by other waste categories shall be minimised as far as practicable
through provision of storage facilities for different categories of waste.
Inert material including soil, rock, concrete, brick, cement plaster/ mortar,
inert building debris, aggregates and asphalt should be segregated from and
stored separate from other waste categories to ensure proper handling and
reuse. The on-site temporary facilities should be equipped with dust control
measures where necessary.
9.3.9
By reducing the quantity of
C&DM requiring off-site disposal through the reuse on-site, the potential
for traffic impacts during the transportation of material will be reduced. The
additional traffic flow due to the transportation of construction material from
vehicle movements in and out of site is considered insignificant.
9.3.10
As described in Section 6.3.20
to 6.3.24, considering the nature of the historical uses of the site and the
fishponds sediment quality sampled, contaminants such as heavy metal,
metalloids and PAHs in the pond mud are well below the Lower Chemical
Exceedance Level (LCEL) of the Sediment Quality Criteria as stipulated in the
ETWB TCW No. 34/2002 - Management of Dredged/Excavated Sediment (i.e. Category
L).
9.3.11
In order to avoid dust, odour
and erosion impacts, all stockpile areas at the site should be covered with tarpaulin
or impermeable sheets. Any vehicle carrying C&D waste should have their
load covered when leaving the works area. Vehicles should be routed as far as
possible to avoid sensitive receivers in the area. The potential air and runoff
impacts caused by handling of excavated materials are presented in the Sections
of Air Impact Assessment and Water Impact Assessment respectively.
Excavated Materials from Construction of WNR
9.3.12
Extensive excavation is not
anticipated during the establishment of WNR, only minor earth works such as
re-profiling and removal of unnecessary bunds will need to be performed.
9.3.13
Since the establishment of WNR
requires substantial amount of soil, in order to minimize waste generation and
reduce the amount of imported soil, all materials generated from earth moving
activities, including dredged pond mud and inert demolition wastes from
unwanted bunds, will be fully and immediately re-utilised on-site as filling
material for the establishment of the WNR. It is estimated that bund removal and
re-profiling will generate less than 100,000m3 of bund materials. This quantity is adequate
for the re-profiling the submerged components of removed bunds and the
formation of small islands. Surplus amount of the materials will be used for
formation of the marshland.
9.3.14
Though unlikely, should marine
disposal of any pond materials be considered, the materials will be subject to
the recommendations of ETWB TCW No.34/2002.
9.3.15
Owing to the substantial amount
of soil required, especially for the formation of the marshland, even when all
dredged pond mud and inert C&D materials are re-used on-site, there is
still a shortfall of materials. The estimated amount of soil needs to be
imported for the establishment of WNR is about 132,700 m3.
9.3.16
For the construction of alternative
egretry during the pre-construction phase, an estimated amount of 1,200 m3 fill materials will be gained
on-site through removing unwanted bunds between existing Pond No. 38 and 40 and
unwanted bunds between Pond No. 37, 39 and 41.
9.3.17
During 4th quarter 2010 to 2nd
quarter 2011, there will be a surplus of 3,000 m3 of bund materials generated from site
clearance and removal of unwanted bunds inside Section 1 and 2 of WNR. To
maximize the opportunity for reducing waste generation, the bund materials can be
temporarily stockpiled at the location of Storage Pond inside WNR and re-used
for Marshland establishment at 4th quarter of 2011. The stockpile
area will be covered with tarpaulin or impermeable sheets to avoid potential
odour and erosion problems.
Excavated Materials from Construction Works at Built Area
9.3.18
At the built area, topsoil of
the existing fishponds will be dredged during the site formation from 4th
quarter 2011 to 1st quarter 2012. The volume of soil is estimated to be in the
amount of 12,300 m3.
Those topsoil will be moved to the marshland area for land formation once they
are dredged, or they can be re-used on-site for the establishment of WNR, for
instance re-profiling of pond bunds, partial filling of ponds, creation of
shallow waters and muddy island during the same construction phase, if
considered necessary.
9.3.19
During the piling works at the
built area from 3rd quarter 2013 to 2nd quarter 2014, about 180 numbers
of 2.5m-diameter
bored piles will be used. The amount of excavated spoil generated will be about
3,530 m3. They can be retained
and re-used as fill materials on site or for landscaping works at the built
area, so to save costs for such works and reduce the transportation and
environmental impacts of disposal.
9.3.20
With the basement car parks at
the built area built on top of the ground level of those dredged ponds (about 2m mPD), the amount of soil need to be
imported for pond filling can be greatly reduced. As the basement car parks
will have site coverage of 70% of the built area, the estimated amount of soil
needs to be imported for pond filling at the built area is estimated to be
about 58,000 m3.
9.3.21
Table 9‑1 summarizes the timing, estimated amount of excavated
materials that could arise, and estimated amount of fill materials required
during the construction of the Project.
9.3.22
As indicated in Table 9‑1, the estimated amount of C&D materials to be
reused on-site is 309,796m3.
The estimated amount of C&D materials generated on-site is 122,861m3 which should be
fully reused on-site. The C&D materials to be reused on-site also include
the C&D materials imported from a public filling area, The amount of
C&D materials imported from the public filling area and to be reused
on-site is estimated to be 186,935m3.
Excavated Materials from Improvement Works of Access Road Leading to
the Site
9.3.23
Since vehicular access to the
Fung Lok Wai site will be via the Fuk
Shun Street, which requires only road widening and
improvement works to link up with the internal access road, this will generate
minimal amount of waste.
9.3.24
Excavation is only required for
the laying of stormwater drains, sewers and other utilities. As the “cut and
fill” approach will be used, the amount of excavated material generated would
be minimized.
Table
9‑1 Sumamry Table of
Estimate Quantity of Materials to be Generated or Imported during the
Construction of the Fung Lok Wai Project
|
Key Construction Activities
|
Duration
|
Estimate Quantity of Material to be
generated (m3)
|
Estimate Quantity of Material to be
reused on site (m3)
|
Estimate Quantity of Materials to be
imported (m3)
|
Estimate Quantity of C&D Materials
to be delivered to and reused in public filling areas (m3)
|
Estimate Quantity of C&D Materials
to be disposed of at landfill areas (m3)
|
Remarks
|
|
Construction of potential alternative
egretry
|
3rd quarter 2010
|
1,200
|
1200
|
-
|
-
|
-
|
Fill Materials will be gained on-site
through removing unwanted bunds between existing Pond No. 38 & 40 and
unwanted bunds between Pond No. 37,39 & 41
|
|
Site Clearance & Removal of unwanted
bunds inside WNR (Section 1, 2)
|
4th quarter 2010 & 2nd quarter 2011
|
71,500
|
-
|
-
|
3000
|
-
|
For the 3000 m3 surplus of bund materials, they
can be temporarily stockpiled on site at location of Storage Pond & used
for Marshland establishment at 4th quarter of 2011
|
|
Re-profiling works for establishment of
WNR
|
-
|
68,500
|
|
Topsoil dredging at built area
|
4th quarter 2011 to 1st quarter 2012
|
12,300
|
-
|
136,200
|
380
|
120
|
No pond filling activities is required to
be performad at the area of storage pond
|
|
Site clearance & Removal of unwanted
bunds at built area
|
5,000
|
-
|
|
Site Clearance of Removal of unwanted
bunds at Marshland
|
27,000
|
-
|
|
Raise level and land formation for
Marshland
|
-
|
180,000
|
|
|
|
|
|
|
|
|
|
|
Pond filling at built area
|
2nd quarter 2012 to 1st quarter 2013
|
-
|
58,000
|
58,000
|
-
|
-
|
|
|
Excavated
spoil generated from piling works
|
3rd quarter 2013 to 2nd quarter 2014
|
3,530
|
1000
|
-
|
1770
|
760
|
The opportunity to re-use the excavated
spoil on-site will be maximized e.g. as fill materials or for landscaping works
at the built area
|
|
Other superstructure works
|
3rd quarter 2014 to 3rd quarter of 2016
|
975
|
-
|
-
|
750
|
225
|
The
opportunity to re-use on-site will be maximized
|
|
Widening of Access Road (including Laying
of drainage, sewerage & utilities)
|
4th quarter 2014 to 3rd quarter 2016
|
1356
|
1096
|
-
|
200
|
60
|
The opportunity to re-use on-site will be
maximized
|
|
Total
|
|
122,861
|
309,796*
|
194,200
|
6,100
|
1,165
|
|
* The “Estimate Quantity of Material to be reused on site” is
greater than the “Estimate Quantity of Material to be generated” because the former also included the “Estimate Quantity of Materials to be imported”, as those
imported C&D materials from public fill area is anticipated to be reused
onsite.
Chemical Waste
9.3.25
As defined under the Waste
Disposal (Chemical Waste) (General) Regulation, chemical waste includes any
substance being scrap material or unwanted substances specified under Schedule
1 of the Regulation. Chemical waste that could be generated from construction
works would primarily arise from chemicals used in operation and maintenance of
on-site equipment. These may include fuel, oil, lubricants, cleaning fluids,
and solvents arising from leakage or maintenance of on-site equipment and
vehicles. Chemical generated from daily
operation of the construction works shall be recycled/ reused on-site as far as
practicable.
9.3.26
The amount of chemical waste
that will be generated from the construction works will depend on the
contractor’s on-site maintenance intention, age and number of plant and
vehicles used. Nevertheless, chemical
wastes such as lubricating oil or solvent generated by workers are not expected
to be in large quantity. The likely
chemical waste types are readily accepted at the chemical waste treatment
centre at Tsing Yi or other licensed waste oil recycling facilities in Hong Kong. The
Centre for Environmental Technology operates a Waste Exchange Scheme, which can
assist in finding potential buyers of chemical for reuse or recycling.
9.3.27
If off-site disposal of
chemical waste is required, they should be collected and delivered by licensed
contractors to Tsing Yi Chemical Waste Treatment Facility and be disposed of in
strict accordance with the Waste Disposal (Chemical Waste) (General)
Regulation. Contractors shall register with EPD as chemical waste producers
when disposal of chemical waste is anticipated to be required. Chemical waste materials have to be stored
on-site with suitable containers and away from water bodies so that leakage or
spillage is prevented during the handling, storage, and subsequent
transportation.
9.3.28
Provided that the handling,
storage and disposal of chemical wastes are in accordance with the Waste
Disposal (Chemical Waste) (General) Regulation and the Code of Practice on the
Packaging, Labelling and Storage of Chemical Wastes, this will unlikely cause
an unacceptable environmental impact.
9.3.29
Spent bentonite slurries, if
any, will be handled and disposed of properly in accordance with the
requirements set out in the Practice Note for Professional Persons (PN1/94)
Construction Site Drainage. Fossil fuel and used lubricants for trucks and
machinery are classified as chemical wastes.
The Contractor shall register with EPD as a chemical waste producer and
observe all the requirements under the storage, labelling, transportation and
disposal of chemical waste.
9.3.30
The Contractor shall prevent
fuel and lubricating oil leakage from plant and storage sites from
contaminating the construction site. All
compounds in work areas shall be positioned on areas with hard paving and
served by drainage facility. Sand/ silt
traps and oil interceptors shall be provided at appropriate locations prior to
the discharge points.
General Refuse
9.3.31
Throughout the construction
phase, the workforce on the construction site will generate a variety of
general refuse requiring disposal. These
refuse will mainly consist of food wastes, aluminium cans, and waste paper,
etc. No information regarding the number
of workers on-site would be available at this early project stage. Nevertheless, assuming that 50 workers are
working together at any one site, and a waste generation rate of about 0.6 kg per person, it could be estimated that
the amount of general refuse that would be generated is in the order of 30 kg per day.
9.3.32
General refuse generated at the
construction site should be stored separate from construction and chemical
wastes to avoid cross contamination. A
reliable waste collector shall be employed by the Contractor to remove general
refuse from the construction site on a daily basis where appropriate to
minimise the potential odour, pest and litter impacts. Open burning for the
disposal of construction waste or the clearance of the site in preparation for
construction work is prohibited under the Air Pollution Control (Open Burning)
Regulation.
9.4.1
To ensure the appropriate
handling of the C&DM, it is recommended that a Waste Management Plan (WMP)
shall be developed by the contractor at the commencement of the construction
works. The WMP should be developed taking into account the recommended control
measures given in this section where appropriate. The WMP shall be submitted to
the Engineer at the commencement of the project for approval.
9.4.2
The following additional
control/ mitigation measures are recommended to be followed by the Contractor:
·
Storage of different waste
types - different types of waste should be segregated and stored in different
containers, skips or stockpiles to enhance reuse or recycling of materials and
their proper disposal. An on-site
temporary storage area equipped with required control measures (e.g. dust)
should be provided;
·
Trip-ticket system – in order
to monitor the proper disposal of non-inert C&D waste to landfills and to
control fly-tipping, a trip-ticket system should be included as one of the
contractual requirements and audited by the Environmental Team;
·
Records of Wastes - a recording
system for the amount of wastes generated, recycled and disposed (including the
disposal sites) should be proposed;
·
Training - The contractor
should provide his workers with proper training of appropriate waste management
procedure to achieve waste reduction as far as practicable and cost-effective
through recovery, reuse and recycling and avoid contamination of reusable
C&DM.
Construction
Waste EM&A Requirements
9.4.3
In order to ensure that each
construction waste stream generated from the construction phase of the Project
are managed in accordance with the procedures recommended in this EIA, it is
recommended that auditing by an Environmental Team be carried out as part of
the overall construction phase EM&A programme. The regular audit should
look at the key aspects of waste management including waste generation,
storage, recycling, reuse, transport and disposal.
Operational Phase Assessment
9.4.4
The proposed residential
development will accommodate a residential population around 5,980 after full
occupation. With reference to the Data from Monitoring in Solid Waste in Hong Kong 1999, the capita generation rates of domestic
waste will be 1.48 kg/day
in 2016. Under such assumption, the estimated quantity of wastes generated from
the Development will be 8,850 kg/day.
9.4.5
Refuse collection chambers
(RCC) will be provided for the residential development. In order to comply with Building Regulation,
mechanical ventilation will be provided. The odour nuisance to the pubic can be
minimized by incorporating the odour absorption system. With proper management
and maintenance of the waste facilities, possible leachate impact from the RCC
is not anticipated.
9.4.6
It is also recommended that
collection bins for used aluminium cans, waste paper and glass bottles should
be provided at strategic locations of the residential development area to
promote and encourage recycling by residents during the operational phase.
9.5.1
The waste streams that would be
generated during the construction and operational phase of the proposed Project
at Fung Lok Wai were identified and evaluated in terms of their nature, type,
quality, quantity, and associated environmental impacts. Opportunities for
reduction in waste generation through recovery, reuse or recycling are
identified.
9.5.2
The waste management
implications and potential environmental impacts associated with the handling,
transport, and disposal of the identified waste types are evaluated and
addressed. An EM&A programme is recommended to be in place during the
construction phase to check the waste generated from the construction site are
being managed in the accordance with the recommended procedures.
9.5.3
Provided that the
recommendations set out in this section are implemented, no waste related
regulatory non-compliance and unacceptable environmental impacts are expected
to arise from the handling, storage, transport and disposal of construction
waste arising from the proposed residential and wetland nature reserve
development.
9.5.4
The nature of the historical
uses of the site and the findings of the sediment sampling results confirm that
land contamination should not be a concern.
9.5.5
10.1.1
This section evaluates and
assesses the cultural heritage impact of the Development in accordance with the
requirements stated in Clause 3.5.8 of the Study
Brief and the criteria and guidelines stated in Section 2 of both Annexes 10 and
19 of the TM.
10.2.1
The objectives of the CHIA are
the following:
·
To identify landscape features
within the Study Area, including sites of historical events, historical field
patterns, tracks and fishponds and cultural elements such as fung shui
woodlands and clan grave sites which will be affected by the proposed
development;
·
To identify direct and indirect
impacts on the nearby historical buildings and structures in the following
villages:
o
Ng Uk Tsuen, including the Tin Hau
Temple and village
houses;
o
Shing Uk Tsuen, village houses;
o
Tai Tseng Wai, village houses;
·
To assess potential impacts
including visual impacts on fung shui/visual corridors of the historical
buildings and structures;
·
To propose measures to mitigate
against identified impacts.
Desk-based Study
10.3.1
A desk-based review was
undertaken to identify the known cultural heritage resources in the broader
Study Area. Research gleaned existing
information and included the following sources: published and unpublished AMO
reports and files, Public Records Office, GEO bore hole data, GEO aerial
photograph library, Lands Department maps and photographs and other relevant
resources.
Historical Buildings and Structures
Survey
10.3.2
A systematic survey of the
Study Areas and potentially indirectly impacted adjacent areas was carried out
in order to record all buildings and structures and parts thereof which were
constructed before the year 1950 and/or otherwise qualify as having heritage value
according to the AMO criteria. Identified cultural heritage resources were
recorded on detailed recording forms, for both their architectural features and
cultural and historical associations. Photographs were taken and the resources
located on 1:1000 maps. The Survey is described in further detail in Section
10.5.
Historical Landscape Features Survey
10.3.3
Field inspections were
undertaken to assess the status, function and conditions of the ponds at
present. The results are presented in
Section 10.6.
Assessment of Impacts and Recommendation
of Mitigation
10.3.4
Data collected from the
previous tasks was examined in the light of previous alterations to the
original landscape and the predicted impacts of the planned development on the
identified and potential heritage resources. The summary of the results of this
assessment and resulting recommendations for mitigation are presented below in
Section 10.7.
Geology and Topography
10.4.1
The Study Area is characterised
entirely by extensive, reclaimed mud flats lying at approximately 4 m PD. The Study Area comprises almost
entirely of undivided, mainly dark grey marine mud and partly silty marine
sands (both belong to the Hang Hau Formation).
These muds and thin stretches of sand are entirely Holocene in age and
are evidence of rapid sedimentation in the Deep Bay
area. Along the southern edge of the Study Area there is a strip of Holocene
marine sands, which represent the earliest shoreline.
10.4.2
These sands in turn lie against
Pleistocene terraced alluvium and debris flow deposits of the original
landform, a north east pointing peninsula
of Lok Ma
Chau Formation metamorphosed
sedimentary and volcanic rock. The peninsula rises to a height of 61.7 m. PD. Debris flow deposits and
terraced alluvium (Pleistocene) form the lower parts of its slopes. The hills
are gently sloping and consist of relatively fine grained deposits of cobbles
and gravel in clayey silt. To the north
west of Ng Uk Tsuen fine granite intrudes the main
geology (Langford R.L., et al.1989).
Existing Impacts
10.4.3
The Study Area does not impact
on the landmass and is thus entirely located in the ponds. The following impacts have occurred in the
Study Area:
·
Re-dividing of the ponds,
changing of their shapes;
·
Temporary structures;
·
Surfacing of the roads
(minimal).
Potential Impacts
10.4.4
The proposed works may have an
adverse impact on the existing landscape.
The following potential impacts may arise from construction:
·
Destruction of sections of the
existing ponds and bunds;
·
Irreversible change of
historical landscape of ponds and bunds;
·
Visual impacts on the
historical villages;
·
Indirect impacts on the graves,
historical villages and/ or structures, etc.
·
Changes in water table levels
and vibration caused by the development
Introduction
10.5.1
The background, methodology and
findings of the historical buildings survey will be presented in this section.
The assessment of any impacts to the recorded resources will also be presented,
as will recommendations for mitigation. It should be noted that the survey
included the actual Study Area as well as three nearby villages, Ng Uk Tsuen,
Shing Uk Tsuen and Tai Tseng Wai, which were highlighted in the study brief.
Potential for Cultural Heritage
Resources in the Study Area
10.5.2
The village of Tai Tseng Wai
was settled approximately 500 years ago.
There are five surnames associated with the village; Cheng, Leung, Shing, Lam and Tang. All of
the families came from Tai Peng, Tung Kwun in Guangdong. The Leung and Cheng families
arrived first. The Shing, Lam
and Tang arrived about 300 years ago. The people here supported themselves
through fishing and farming in the area. Farming was abandoned approximately 20
years ago.
10.5.3
The village of Shing Uk Tsuen
was settled approximately 400 years ago. It is a single family surname village,
i.e. Shing. The families came from Guangdong
province. The area behind the village was used to grow crops such as sweet
potatoes and peanuts. Many of the men from the villages, traditionally worked
abroad.
10.5.4
The village of Ng Uk Tsuen
is a single surname village, Ng. The 1st generation ancestor was called Ng Hung
Lan, who came from Nam Tau. The current generation is the 29th. The Ng family
of Ng Uk Tsuen is related to the Shing family of Shing Uk Tsuen by marriage.
The villagers supported themselves through farming rice, in rented fields and
through fishing and catching crabs in Deep Bay.
10.5.5
The three villages all share
the gods hall in Tai Tseng Wai and the Tin Hau temple near Ng Uk Tsuen.
10.5.6
The fishponds in the Study Area
were owned by people from Shek Ha in mainland China and some Tanka families. The
ponds were first used in the 1920’s
for harvesting of shrimp, fish and crabs. The usage of the area as fishponds
continues today. The aerial photographs did show evidence of a settlement that
contained two structures in 1949, see Figure
10‑2, more than a dozen units in 1963, see Figure 10‑3 and no evidence of any units in 2000, see Figure 10‑4. It is possible that these were the homes of the
Tanka people who worked in the ponds.
Background
10.5.7
The Study Area consists of a
series of ponds, separated by bunds. The structures currently in place here
were all found to be of recent construction and of a temporary nature, see Figure 10‑5. The three villages highlighted in the brief (as
listed below) contained a total of 112 structures.
·
Ng Uk Tsuen
·
Shing Uk Tsuen
·
Tai Tseng Wai
10.5.8
The recorded features included
domestic structures, village gates, a temple, shrines and a village well. The
villages were all easily accessible and this allowed for relatively
straightforward identification of the historical and cultural resources. The
field survey also included identification of burial associated sites and fung
shui features, see sections 10.5.15 and 10.5.16 respectively.
Historical Buildings and Structures
Survey Methodology
10.5.9
The structures within the Study
Area as well as those in the villages were surveyed and assessed on an
individual basis. The survey consisted of a field evaluation incorporating the
collection of photographic, oral and written information, on the architecture
and history of all historical structures to be impacted by the proposed
development. This information was recorded on specially designed forms, (either
a full ten page form, or in cases where the structure could be adequately
described in less space, a one page summary form). These forms were designed to
provide a complete documentation of all identifiable pre-1950 structures, as
well as any more recent structures of cultural/ historical significance.
Architectural features and structural modifications, as well as historical
attributes, such as previous uses and past associations with local families or
prominent personages are documented on the forms. The design of the forms is
based on AMO and ICOMOS (International Charter for the Conservation and
Restoration of Monuments and Sites) standards for the recording of historical
resources with modifications to suit architectural styles and situations
encountered in Hong Kong. The recording forms
also include general information about the structure, such as location,
building type, usage and ownership. The forms have been compiled to create a
catalogue, which is included in this report, see Appendix 10-1. As well, a
synopsis of each structure is presented below and the locations of the
historical/ cultural resources highlighted on 1:1000 scale maps (see Figure 10‑6, Figure
10‑7 and Figure
10‑8 and Figure
10‑8a).
10.5.10
The data gathered from the
field survey for the individual heritage resources along with the information
from previous desk based research was used to prepare assessments of the
historical resources and formulate mitigation recommendations.
Synopses of Recorded Structures and
Village Summaries
10.5.11
All of the recorded structures
were located in the three villages and are presented in synopsis form below.
The actual Study Area was found to contain no cultural heritage resources of
any kind.
Shing Uk
Tsuen (Figure
10‑6)
10.5.12
This village contains a number
of traditional structures. Many of the domestic structures were courtyard style
terraces. The majority of these structures were either abandoned or closed up
and not being used as houses. Many of the modern replacement structures date to
the 1970’s and 1980’s. There is no current building
activity going on in the village. There are still a number of cut stone pieces,
taken from demolished buildings, in the village.
FLW-01-01 Kwong Ling
Tong (Tse Tong). A 1971 structure built on the site of an older Study Hall. Two
storey concrete building, flat roof, balcony on first floor façade. Parapet
with red star and 1971 on façade.
FLW-01-02 Ruins of a
single storey green brick shed. Front section partially intact, middle and rear
destroyed. Pre-1950 in
date.
FLW-01-03 Green brick, end
terrace, courtyard style house. Decorative canopy over main entrance door.
Frieze panels in poor condition on façade and right wall and gable.
Approximately 100 years old.
FLW-01-04 Compound with
Green brick house and attached structures. The house has traditional exterior
maintained and tile and concrete roof.
FLW-01-05 Tree and shrine.
Large Banyan tree with small shrine about 1 metre in front (by entrance gate to
village). Shrine consists of small standing stone with concrete enclosure and
incense holder.
FLW-01-06 Row of five
green brick courtyard style terrace houses. Facades have been all been heavily
modified, although interiors are relatively intact. The row is approximately 60
years old.
FLW-01-07 Two green brick,
courtyard style, terrace houses, one end/ one mid terrace. Modern entranceways
and canopies have been added. Frieze decorations in poor condition. Roof is
entirely flat. Approximately 65 years old.
FLW-01-08 Green brick
courtyard style house, end terrace (right end) structure on left hand side has
been demolished. Decorative frieze and canopy intact. Pre-1950 in date.
FLW-01-09 Concrete over
pounded earth courtyard style structure. Concrete roof. Pre-1950 in date.
FLW-01-10 Row of three
green brick terrace houses (courtyard style).
Left hand pair are intact, right hand side unit is ruinous (façade only
remaining). All facades retain decorative canopies and friezes.
FLW-01-11 A row of three green
brick, courtyard style houses. Traditional facades (apart from modern gates on
right hand two) with decorative features in poor condition. Pre-1950 in date.
FLW-01-12 Four green brick
houses, intermediate terrace, courtyard style. Single course of granite at
foundation on façade. Traditional features retained.
FLW-01-13 End terrace,
green brick, courtyard style house. modern door. Decorative frieze and canopy
in fair to poor condition. Pre-1950
in date.
FLW-01-14 Two green brick,
courtyard style terrace houses. The right hand unit is a ruin. Left hand unit
has traditional interior (altar in rear). The units are 1950 in date.
FLW-01-15 Small shed made
of mixed colour bricks and pitched tile roof. No decorative features..
FLW-01-16 Row of three
green brick, courtyard style terrace houses. Only left hand unit is occupied,
other two are ruins. Attached structure on right hand unit is also ruinous,
stone and pounded earth material.
Decorative canopies on above entranceways. Pre-1950 in date.
FLW-01-17 Mixed brick
terrace house. Single pitched roof, (tile and concrete) . Roughly cut stone
foundation. Pre-1950 in
date.
FLW-01-18 Shing Ka Tse.
Tse Tong. Two storey modern building. White pebble texture tiling on exterior.
FLW-01-19 Abandoned brick
and stone building. Very overgrown with vegetation. No windows or doors. . Pre-1950 in date.
FLW-01-20 Row of three
structures with two green brick courtyards style units with front section only
remaining. Third structure almost completely collapsed.
FLW-01-21 Row of five
courtyard style houses, green brick. Relatively unaltered (except right hand
two have metal gates). Decorative canopies above entranceways. Pre-1950 in date.
FLW-01-22 Red and green
brick two part structure. Arched doorway on right hand structure. Pre-1950 in date.
FLW-01-23 Row of brick and
concrete animal pens. Possibly about 50 years old in portions.
FLW-01-24 Two green brick,
courtyard style terrace houses. One end, one intermediate with adjoining unit
demolished. Both units abandoned. Canopies and frieze on façade in poor
condition.
FLW-01-25 Green brick and
stone house ruins. Stones in left hand wall are uncut, except on corner.
Remains of interior, overgrown. Pre-1950
in date.
Tai Tseng Wai (Figure 10‑7)
10.5.13
This village contained a number
of older buildings. The majority of them were terrace houses, constructed of
brick with no decorative features and a single pitched roof. The houses often
had foundations of uncut or very roughly cut stones. A number of the houses
were abandoned, used only for storage or housing family shrines. The
traditional houses that were still being occupied often had alterations such as
window additions, modern doors/gates and air conditioner units. As was seen in
the village of Shing Uk Tsuen, most of the replacement
village houses appear to have been constructed during the 1960’s and 1970’s.
FLW-01-26 Shrine, concrete
with paint and stucco. Recent construction
FLW-01-27 Gate of village.
Traditional and modern features. Incense holders and burners, exterior and
interior. Shrine with village god figure to left of entryway.
FLW-01-28 Single storey
brick house, pitched roof. In use, no decorative features remaining. Pre-1950 in date.
FLW-01-29 Gate within the
village, leading to three houses. Mixed colour brick material with stone
threshold. Small recess in interior wall with incense holder. The gate is
attached to houses and appears to be of similar date, pre-1950.
FLW-01-30 Row of two green
brick courtyard style houses. Decorative
canopy and frieze on façade. Tile and concrete roof. Pre-1950 in date.
FLW-01-31 Green brick
courtyard style, end terrace house. Decorative canopy and frieze. Pre-1950 in date.
FLW-01-32 Courtyard end terrace, green brick house. No decorative
features remaining. Pre-1950 in
date.
FLW-01-33 Green brick end
terrace courtyard style house. Decorative canopy above door, molded frieze on
façade. Pre-1950 in date.
FLW-01-34 Green brick
courtyard style house. Canopy above door. Pre-1950 in date.
FLW-01-35 Pair of
two-storey green brick terraces. Balcony over front section of structures. Pre-1950 in date.
FLW-01-36 Section of brick
wall
FLW-01-37 Green brick courtyard
unit. Parts of façade wall intact. Pre-1950
in date.
FLW-01-38 Two green brick
courtyard style houses. Interior collapsed. Pre-1950 in date.
FLW-01-39 Modern Gods’
Hall.
FLW-01-40 Yee Hing Tong
(Cheng Family Study Hall). one and a half stories (with loft). Entrance door
off centre to left. Pre-1950 in
date.
FLW-01-41 Brick house next
to the Study Hall. Only decorative feature, molding under eaves on façade. Pre-1950 in date.
FLW-01-42 Three abandoned
terrace houses, single pitched roofs, green brick and stone foundation. Houses
date to pre 1900.
FLW-01-43 Mixed brick
house. Single pitched roof. No decorative features. Pre-1950 in date.
FLW-01-44 Three mixed
brick houses. Single pitched roof. No decorative features. Terrace. Pre-1950 in date.
FLW-01-45 Two intermediate
green brick terrace houses, single pitched roofs. Pre-1950 in date.
FLW-01-46 Five abandoned
terrace houses. Green brick and stone foundations. Pre-1950 in date.
FLW-01-47 Green brick and
pounded earth house, with rough cut stone foundation. Pre-1950 in date.
FLW-01-48 Ruins of three
structures, green brick wall portions remaining.
FLW-01-49 Green brick
terrace house, single roof. Stone foundation. Pre-1950 in date.
FLW-01-50 Brick and
pounded earth terrace house, single pitched roof, partially collapsed. Pre-1950 in date.
FLW-01-51 Ruin of two
houses, green brick and mud stone walls with stone foundations. Pre-1950 in date.
FLW-01-52 Green brick
structure, end terrace, concrete added around foundation. Single pitched roof.
Pre-1950 in date.
FLW-01-53 Ruins of a
house, mud brick walls and wooden beams in very poor condition. Pre-1950 in date.
FLW-01-54 Green brick,
intermediate terrace, single pitched roof. Pre-1950 in date.
FLW-01-55 Green brick
terrace house with stone foundation, in very poor condition.
FLW-01-56 Mixed brick
terrace house, single pitched roof. Poor condition. Pre-1950 in date.
FLW-01-57 Green brick
house, part of former terrace. Single pitched roof. Pre-1950 in date.
FLW-01-58 Mixed brick
house, single pitched roof. Not in use. Pre-1950
in date.
FLW-01-59 Two terrace
houses, end terrace and intermediate. Green brick with stone foundation, some
sand stone pieces. Pre-1950 in
date.
FLW-01-60 Row of three
terrace houses. Green brick, single pitched roof. Pre-1950 in date.
FLW-01-61 Ruin
of green brick house, portions of walls remaining. Pre-1950 in date.
FLW-01-62 Three green
brick terrace houses. Single pitched roofs. Pre-1950 in date.
Ng Uk
Tsuen (Figure
10‑8a and Figure 10‑8b)
10.5.14
This village contained a number
of traditional structures in various conditions, ranging from completely
ruinous to inhabitable.
FLW-01-63 Tin Hau Temple,
rebuilt in 1981. All modern features
FLW-01-64 Small earth god
shrine consisting of wooden boards behind two stones, and brick incense holder
FLW-01-65 Courtyard
terrace house. Decorative canopy and frieze on façade. Pre-1950 in date.
FLW-01-66 Two mixed brick
terrace houses. Forecourts very overgrown. Single pitched roofs. Over 100 years
in age.
FLW-01-67 Ruins of two
courtyard terrace houses. Decorative canopies still intact, but poor condition.
Over 100 years in age.
FLW-01-68 Courtyard style
terrace house. mixed brick façade and rammed earth and render side walls.
Collapsing roof. Pre-1950 in
date.
FLW-01-69 Green brick and
concrete (heavily altered) intermediate terrace. Canopy over doorway in fair
condition. Portions of structure pre-1950
in date.
FLW-01-70 Section of brick
wall and collapsed pounded earth section.
FLW-01-71 Green brick
courtyard style unit with modern flat roof on front and added middle section on
roof with access to front roof area.
FLW-01-72 Small single
room pounded earth and render covered shed.
Pitched tile roof. Modern door and windows.
FLW-01-73 One mixed brick
courtyard terrace house ruin Decorative canopy above door, very poor
condition. Pre-1950 in date.
FLW-01-74 Ruins of a green brick building, lower
walls remaining in places.
FLW-01-75 Two courtyard
style houses. Mixed brick and portions of walls covered in render.
Approximately 100 years in age.
FLW-01-76 Modern Study
Hall (Kwong Cheung
Study Hall). Named after an ancestor.
FLW-01-77 Row of four
courtyard style terrace houses. Green brick.
Over 100 years in age.
FLW-01-78 Three green
brick courtyard style terrace houses. Stone foundations visible in two units.
Decorative canopies, poor condition. Pre-1950
in date.
FLW-01-79 Modern Tse Tong
(Wing Yick Tong).
Two storey, tile exterior.
FLW-01-80 Row of four
courtyard terrace houses. Green brick, decorative canopies over the doorways. Pre-1950 in date.
FLW-01-81 Green brick,
courtyard terrace style house, in ruins.
Façade intact with decorative canopy. Pre-1950 in date.
FLW-01-82 Well with
shrine. Concrete platform. Granite blocks well lining.
FLW-01-83 Row of two green
brick houses, courtyard terrace houses. Modern parapets 1965 and 1972
renovation dates. Original houses pre date 1950.
FLW-01-84 Row of two green
brick terrace houses. Decorative canopies intact. Fung shui wall opposite. Pre-1950 in date.
FLW-01-85 Originally part
of a row of eight terrace houses, two missing. green brick, mud brick, cement,
modern materials. No decorative features. Built during the Japanese occupation
according to local informant.
FLW-01-86 Originally a row
of eight terrace houses. Two green brick, mud brick, cement, modern materials.
No decorative features. Built during the Japanese occupation according to local
informant.
FLW-01-87 Green brick
terrace, no decorative features. Approximately 100 years old.
FLW-01-88 Village
entrance gate. Pale green brick with tile and concrete
roof. Wooden loft inside two shrines.
FLW-01-89 Earth god shrine
in concrete area in front of rural committee building. Stones are set directly
into the cement. Incense holder in ground.
FLW-01-90 Large Pak Kung shrine. Green brick,
cut stone and cement. Wok yee gable
sides, recessed altar in rear wall, large platform for incense holder.
FLW-01-91 Kam Yan public
school. Not in current use. brick, concrete and chunam exterior.
of the
main entrance that were taken from a boat that ran aground in the area about
100 years ago.
FLW-01-92 Shrine in a
concrete open area, cut stone blocks and incense holder. Large whetstone also
set into concrete.
FLW-01-93 Mixed brick shed
attached to rear of modern structure. Tile and concrete roof. Traditional
building materials, but age indeterminate.
Burial Associated Sites
10.5.15
The elevated area behind the village of Ng Uk Tsuen, including the fung shui
wood contains a number of graves, kam tap and coffin slots. The location of the
grave area is highlighted in Figure
10‑9. None of the graves lie within the Study Area.
Fung Shui Features
10.5.16
A large area of fung shui wood
is located behind the village of Ng
Uk Tsuen. There are a mixture of tree species and many
mature specimens. It is forbidden to cut trees in the area (according to local
informant. The location of the fung shui wood is illustrated in Figure 10‑9. The limit of the fung shui wood is entirely outside
of the Study Area.
Impact Assessment
Resources within the Study Area
10.5.17
The following impacts were
considered for any built heritage features within the Study Area; visual/
aesthetic, changes in water table and damage from vibration during
construction.
10.5.18
No historical buildings or
structures, archaeological deposits, fung shui features or burial features were
recorded within the Study Area. The development will therefore have no direct
impacts.
Resources outside the Study Area
Table 10‑1 The impacts associated with cultural
heritage resources outside the Study Area
|
Resource
|
Description
|
Orientation/ Distance
|
Impact
|
|
Ng Uk Tsuen Village (including the Tin
Hau temple)
(FLW-01-63 to FLW-01-93)
|
·
An
historical village containing 37recorded cultural heritage resources,
including a Tin Hau temple
·
The
land between the village and the Study Area is wooded
·
The
land surrounding the Tin Hau temple contains working concrete fishponds and
woodland
|
Away from/ 250
m
|
No discernible impacts
|
|
Shing Uk
Tsuen Village
(FLW-01-01 to FLW-01-25)
|
·
An
historical village containing 25 recorded cultural heritage resources
·
There
are numerous modern structures in the vicinity of the village
|
Away from/ 200 m
|
No discernible impacts
|
|
Tai Tseng Wai Village
(FLW-01-26 to
FLW-01-62)
|
·
An
historical village containing 31 recorded cultural heritage resources
·
The
village is situated in a lowlying area
·
There
are numerous modern structures in the vicinity of the village
|
Away from/ 350 m
|
No discernible impacts
|
|
Burial Associated Sites
|
·
Graves and kam tap associated with the local villages
·
Graves
are located along hillsides overlooking the Study Area. The graves overlook
the proposed development site.
|
Varied/ 100 m
|
No discernible Impacts
|
|
Fung Shui Woods
|
·
Mixed
species woodland located behind the village of Ng Uk Tsuen
still regarded as having fung shui importance (according to local informants)
|
Not Applicable/ 150 m
|
No discernible impacts
|
Mitigation Recommendations
Resources within the Study Area
10.5.19
There were no recorded
resources in the Study Area, therefore, none of the above-mentioned impacts are
relevant and no mitigation measures are required.
Resources outside the Study Area
Table 10‑2 Mitigation Recommendations for Cultural
Heritage Resources Outside the Study Area
|
Resource
|
Assessment Factors
|
Mitigation Recommendation
|
|
Ng Uk Tsuen Village
|
·
The
Study Area is not visible from the village because of woodland and modern
buildings
·
The
village is oriented away from the Study Area
|
·
No
further mitigation measures are necessary
|
|
Shing Uk
Tsuen Village
|
·
The
Study Area is not clearly visible from the village, as it is located in an
area containing many modern housing units
·
The
village is oriented away from the Study Area
|
·
No
further mitigation measures are necessary
|
|
Tai Tseng Wai Village
|
·
The
Study Area is not clearly visible from the village as it is situated in a
lowlying area and the area immediately surrounding the village contains
numerous modern housing units
·
The
village is oriented away from the Study Area
|
·
No
further mitigation measures are necessary
|
|
Graves
|
·
the
graves lie outside the boundaries of the proposed development
·
the
graves overlook the Study Area
|
·
No
further mitigation measures are necessary
|
|
Fung Shui Wood
|
·
The
fung shui wood lies outside the boundaries of the proposed development
|
·
No
further mitigation measures are necessary
|
Changing Historical
Land use Patterns within the Deep Bay
Area
10.6.1
The earliest useful map of this
portion of the New
Territories is the
cadastral survey carried out by Newland in 1903. This map shows the deeply
indented coastline of the southern shores of Deep Bay,
fringed by mangroves (Irving Richard T.A. and Leung Kai Wing 1987). The area of Fung Lok Wai is shown as swamp
and marsh in 1903. The situation remains unchanged at least until 1913 as can
be established from a topographical map (GEO old maps section).
10.6.2
By 1924 survey maps and an aerial
photograph, see Figure
10‑10 (GEO Ref.# Y00159) show a major reworking of the
mangrove environment. The process of reclaiming mangrove swamp for rice
cultivation was arduous and time-consuming. It required the clearance of paths
in the mangroves along which bunds were constructed. These were built of mud
dug from the swamp and piled over stones to a height of up to 3m and a width of 20m at the base.
Sluice gates were built into the walls to control drainage.
10.6.3
After initial draining, several
years passed before cultivation was possible, during which salinity levels were
gradually lowered by flushing with fresh stream water (Irving and Leung
1987). When sufficiently low, a variety
of brackish water tolerant rice known locally as “haam moon” was planted. This
tolerant strain was relatively high yielding with a long growing season, which
allowed only one harvest per year. The quality of the rice was poor and it was
used primarily for the production of rice wine.
10.6.4
During the period between 1938
and 1945 the Deep
Bay area was transformed
into gei wai. The only known account of
how gei wais are constructed can be found in Richard T. A. Irving and Leung Kai
Wing’s publication (1987). The gei wai's are shallow intertidal ponds enclosed
in earth dykes with sluice gates. Each of the gei wai had channels running
around its perimeter and across the centre which acted as sheltering areas for
the shrimps. Between the channels were stands of mangrove, which were
maintained for fuel wood. The gates allowed water to flood the gei wai at high
tide in autumn and flush shrimp larvae into the pond. In April, when the shrimp
were mature, the pond was drained at low tide and the shrimp caught in a net
across the sluice gate. Over 20 kg
of shrimp could be harvested from a gei wai each time, and each pond could be
harvested many times from April
to October when the season ended. The increase in reclamation
for gei wais during these years seems to be related to the large number of
refugees who came to Hong Kong following the Japanese invasion of China.
Many of these new arrivals came from mangrove areas of the Pearl
River such as His-hsiang, with a long tradition of shrimp
cultivation in shallow ponds. It would seem likely that much of the knowledge
and techniques were brought by such immigrants during this period.
10.6.5
By 1974 the land use of the
area was converted to ponds for raising fresh water fish. These ponds are
substantially deeper than gei wai, measuring about 2 m deep. They exhibit a different impact on the
landscape being stripped of vegetation while the shrimp ponds have mangroves
growing in them. Shrimps are introduced naturally into the gei wai; however,
the fishponds are completely enclosed and are stocked by the introduction of selected
species.
10.6.6
The tradition of fresh water
fish cultivation in ponds goes back centuries in the New Territories.
However, it was not until after the World War II and the introduction of
pumping and stocking technology that intensive conversion to fishponds took
place. The ponds are stocked with fry and then fertilized regularly until the
fish are of marketable size. The pond is then drained and the fish netted.
Recording of Historical Landscape
Features within the Study Area
10.6.7
Figure 10‑11 shows the evolution of the bunds in the Study Area
from 1924 to 2000.
10.6.8
In 1924 the areas along the
landmass are small plots as can be established from the aerial photograph, see Figure 10‑10 (GEO Ref.# Y00159) and according to local informants
were used for brackish rice cultivation.
The villagers rented these plots from the people of Shek Ha. The date of
1924 correlates with the local knowledge of the start of ponds about 80 years
ago.
10.6.9
Even at this stage the basic
plan of the Study Area of two parallel zones can be established. The most
northern zone at this stage consists of large shallow plains divided by
bunds. The southern zone has smaller divisions
and was mainly for fish and shrimp production according to the villagers.
10.6.10
The same inherent pattern is
evident in the 1949 aerial photograph (LD Ref# 6102 and 6181) and the 1957
topographical map (GEO old maps section). The strip along the landmass in 1949
was used for smaller agricultural cultivation, while the southern zone still
had the small divisions but was in use as fish and shrimp ponds. The northern
zone remained unchanged and still consisted of large marshy plains bordered by
bunds.
10.6.11
The 1957 topographical map does
not show the smaller plots along the landmass, but the zones are basically the
same. While the aerial photograph dating back to 1963 shows that the small
cultivation plots along the landmass were still in use (GEO Ref.#Y09690). The
southern zone in 1963 shows along its southern border some small agricultural
cultivation plots with smaller bunds and on its western side three largish
ponds. However, the larger part of the southern zone consisted of very large
gei wai's with some visible drainage channels.
10.6.12
The 1975 aerial photograph of
the Study Area (LD Ref# 10972) shows flooded ponds at the southern end of the
southern zone, while the rest are dry gei wai’s. The strip along the landmass
and around the small hill by this time had been converted to functioning ponds.
An aerial photograph dating back to 1983 (GEO Ref.#48647) indicates that at
this time the Study Area had been divided into small to medium size plots and
these were functioning fish and shrimp ponds.
The basic division of strip along the landmass, southern and northern
zone remains.
10.6.13
Field evaluation of the Study
Area in early 2001 concluded that the strip along the landmass too has been
largely converted into functioning ponds. The local informant and evidence in
the field indicates that the ponds have a depth of a couple of meters only,
while no great conversion to fresh water ponds ever occurred. At present
activities have largely ceased and most of the sluices seem to be no longer
functional. Some of the bunds have been hardened for transport reasons, other
bunds are more modest in appearance. These features are illustrated in the
photographs in Figure
10‑12.
10.6.14
The terminology used above to
describe the landscape is ponds or gei wai’s.
The term gei wai is used for a shallow pond which has channels running
around its perimeter and across its centre. These channels act as shelter areas
for the shrimp. When ponds with gei wai characteristics could be established
from the aerial photograph the term gei wai was used. However, if the gei wai
or pond was filled with water and the shape of the pond could not be seen the
more general term pond is used.
10.6.15
The use of different terms in
this report refers to the specific shape of the pond or gei wai where it could
be established. The literature and local knowledge both refer to shrimp and
fish production as the function of the ponds in the Study Area.
Historical Landscape Features Impact
Assessment
10.6.16
The literary evidence, local
knowledge, maps and aerial photographs indicate that the area had a landscape
of marshland at the beginning of the 20th century. The area has been in use for
shrimp and fish cultivation from as early as 1924 as can be established from
the aerial photograph. Although the
basic pattern of bunds has been retained, the pond sizes and shapes have been
extensively changed over time.
10.6.17
The proposed construction and
associated works will have a direct impact on the bunds. Some of the larger
bunds have more or less existed in their original pattern since the start of the
shrimp and fish cultivation. They are indicated in red on Figure 10‑11.
10.6.18
Upon the completion of the
project, a large portion of the Site will be preserved as fish ponds, the
existing fish pond landscape features will therefore be largely conserved. As the preserved fish ponds will be managed
following traditional aquaculture management practices, the cultural heritage
of traditional fish farming will also be conserved at the same time.
Mitigation Recommendations for Impacted
Resources
10.6.19
Because of the lack of
information concerning the materials and methods used to construct the oldest
bunds. It is recommended that during site formation when a bund is cut or a '
section' is exposed, the section shall be recorded. It is recommended that this
would be a requirement at the site formation stage.
Historical Buildings and Structures
Survey
Findings and Assessment
·
There were no cultural heritage
resources located in the Study Area. All structures were identified as modern
squatter structures with no cultural heritage features
·
The three villages highlighted
in the study brief were found to contain 93 cultural heritage resources
·
A number of graves were
identified on the hill behind the village
of Ng Uk Tsuen (outside
of the Study Area)
·
A fung shui wood was identified
behind the village
of Ng Uk Tsuen (outside
of the Study Area)
Recommendations
·
The Study Area contained no
cultural heritage resources, thus, no mitigation measures are required
·
The cultural heritage resources
outside the Study Area were found to warrant no further mitigation measures
based on the following factors:
o
Adequate screening from the
development site through existing woodlands, topographical setting and modern
structures
o
Sufficient distance from the
development site
o
Orientation away from the
development site
Historical Landscape Features
Findings and Assessment
10.7.1
The assessment has found that
although the basic pattern of the bunds was retained, the bunds have been
extensively changed in size and shape.
Recommendations
10.7.2
In order to retrieve
information concerning the composition of the bunds it is recommended that a
brief recording exercise with methodology agreed with the Antiquities and
Monuments Office be carried out during site formation.
1.
AMO published and unpublished
files
2.
GEO Aerial Photograph Library
and Old Maps Section
3.
Lands Department Aerial
Photographs
4.
Chan Wai Yung 1993. An
Analysis of the Policy on Building in tin Shui Wai New Town. Master of Public
Administration Dissertation.
5.
Irving Richard T.A. and Leung
Kai Wing 1987. Land-use and land-use change in the reclaimed coastal areas of Deep Bay.
6.
Irving Richard and Brian Morton
1988. A Geography of the Mai
Po Marshes. World Wide Fund for Nature Hong
Kong.
7.
Langford R.L., K.W. Lai, R.S.
Arthurton and R. Shaw 1989. Geology of the Western New Territories. ( Hong Kong Geological Survey Memoir, 3), Geotechnical
Control Office (CESD).
8.
Lee Chi Ming, Ng Suk Wan and To
Lap Kee 1987. City on heavenly waters. An Evaluation of tin Shui Wai New Town
Development. MSc. Group workshop report.
9.
Leung Wai Hung 1996.The
Conservation of coastal wetlands,
especially the mai Po
Marshes, in Hong Kong:
Problems and prospects. MSc Dissertation University
of Hong Kong.
10.
Melville D.S. and Brian Morton
1983. Mai Po Marshes. World Wildlife
Fund Hong Kong.
11.
Parish Faizal 1997. The Asian
Region. An Overview of Asian Wetlands. Hails A.J. (Ed.) Wetlands, Biodiversity
and the Ramsar Convention, Chapter 4.
12.
Poon Sau Man 1997. Dredging and
Reclamation Impact on Marine Environment in Deep Bay.
MSc. Environmental Management University of Hong Kong.
13.
da Silva Armando M. 1977.
Native Management of Coastal Wetlands in Hong Kong: A Case Study of Wetland
Change at Tin Shui Wai Agricultural Lot, New
Territories. Geography PhD Dissertation
University of Hawaii.
14.
World Wildlife Fund 1985.The
fascinating water’s edge. Hong Kong.
15.
Young Lew 1997. Mai Po Marshes:
Conserving Wetland Biodiversity through Shrimp Farming. Hails A.J. (Ed.)
Wetlands, Biodiversity and the Ramsar Convention, Chapter 4.
11.1.1 The aim of this section of the report is to describe legislation and
guidelines that will be reviewed in the LVIA.
The landscape baseline reviews the condition of existing landscape
resources (LRs) and landscape character areas (LCAs), planning and development
control framework, and the visual amenity and visually sensitive receivers
(VSRs). The assessment identifies potential
landscape and visual impacts that would occur during the construction and
operational phases of the proposed development at Fung Lok Wai, recommends
landscape mitigation measures to alleviate the impacts; and identifies residual
effects apparent after mitigation. This section also outlines any cumulative
impacts arising from the proposed development and concurrent projects.
11.2.1 Legislation, Standards, Guidelines and Criteria relevant to the
consideration of landscape and visual impacts in this report include the following:
·
Environmental Impact Assessment
Ordinance;
·
Technical Memorandum on
Environmental Impact Assessment Process;
·
EIAO Guidance Notes 8/2002 on
Preparation of Landscape and Visual Impact Assessment under the EIAO.
·
WBTC No. 3/2006 on Management
and Maintenance of Natural Vegetation and Landscape Works and Tree
Preservation;
·
WBTC No. 7/2002 on Tree
Planting in Public Places;
·
ETWB TCW No. 2/2004 Maintenance
of Vegetation and Hard Landscape Features.
·
Final Report of Study on the
Ecological Value of Fish Ponds in Deep
Bay Area (Planning
Department, September 1997)
11.2.2 These are described in detail below:
Environmental Impact Assessment Ordinance
11.2.3 The Environmental Impact Assessment Ordinance (EIAO) was implemented
on 1 April 1998.
Its purpose is to avoid, minimise and control the adverse impact on the
environment of designated projects, through the application of the EIA process
and the Environmental Permit (EP) system.
Technical Memorandum on Environmental Impact Assessment Process
11.2.4 The landscape and visual impact assessments have been carried out in
accordance with the guidelines contained in Annexes 10 and 18 of the Technical
Memorandum on EIA Process.
EIAO Guidance Notes 8/2002 on Preparation of Landscape and Visual
Impact Assessment under the EIAO
11.2.5 The guidance note (GN) advises on the requirements in vetting
Landscape and Visual Impact Assessment (LVIA) of designated projects (DPs)
under the Technical Memorandum on EIA Process (EIAO-TM) for the Environmental
Impact Assessment (EIA) Ordinance. The main aim is to facilitate practitioners
to prepare LVIA and to satisfy their own Quality Management System prior to
making submissions under the EIA Ordinance.
WBTC No. 3/2002 on Management and Maintenance of Natural Vegetation
and Landscape Works and Tree Preservation
11.2.6 This Circular defines the management and maintenance
responsibilities for natural vegetation and landscape works, including both
softworks and hardworks, and the authorities for tree preservation and felling.
WBTC No. 7/2002 on Tree Planting in Public Works
11.2.7 This Circular affirms the advocated policy on tree planting which
adopts a flexible and balanced approach in the planning and design of public
works.
ETWB TCW No. 3/2006 Tree Preservation
11.2.8 This Circular defines the management and maintenance responsibilities
for natural vegetation and landscape works, including both softworks and
hardworks, and the authorities for tree preservation and felling.
Final Report of Study on the Ecological Value of Fish Ponds in Deep Bay
Area (Agreement No. CE 72/94, Planning Department, September 1997.
11.2.9 This Study reviews the past ecological and landuse changes in Deep
Bay Area and assesses the cumulative impact on carrying capacity of changes of
landuse within the Study Area. The Study also reviews the appropriateness of
the Buffer Zone 1 and 2 boundaries and considers alternative beneficial uses
apart from fish farming. The Study sets out guidelines for wetland creation,
restoration and new development sites within the Study Area.
Landscape Impact Assessment Methodology
11.3.1 Preparation of LVIA is based on the EIAO GN 8/2002 “Preparation of
Landscape and Visual Impact Assessment under the EIAO” for evaluation of the
proposed development options at Fung Lok Wai including access road options. The landscape and visual impact
considerations concerning the selection of an access road alignment to the
development site is discussed in Section 3.
The methodology for the LVIA and the selection of preferred development
options is described in the following sections.
Selection of Preferred Development Option
11.3.2 The description of alternative development options provided in
Section 3 of this report includes a consideration of the development
constraints, the alternative master plan layouts with different building height
for three master layout options and two access road options.
Landscape Planning Review
11.3.3 A review of the existing planning studies and documents will be
undertaken as part of the baseline study to gain an insight into the planned
role of the site, its surrounding areas, and its landscape context and to help
determine the projects fit into the wider existing and future landscape
context. This review considered Outline Zoning Plan numbers S/YL-LFS/7, Lau Fau
Shan and Tsim Bei Tsui; S/TSW/11 Tin Shui Wai; S/YL-PS/11 Ping Shan and S/YL/17 Yuen Long. Compatibility of the proposed
development to the planned developments either within or adjacent to the Study
Area are also considered in terms of landscape and visual impacts.
Landscape Baseline
Review and Impact Assessment
11.3.4 The assessment of the potential impacts of a proposed scheme on the
existing landscape comprises two distinct sections namely the baseline survey
and the landscape impact assessment. Landscape Impact Assessment (LIA) Study Area
is taken to include all areas within 500m
of the site boundary.
11.3.5 A baseline survey of the existing landscape resources and landscape
character has been undertaken based on a combination of desktop studies and
site surveys. The landscape elements which contribute to the landscape
character include:
·
Local topography;
·
Woodland extent and type;
·
Other vegetation types;
·
Built form;
·
Patterns of settlement;
·
Land use;
·
Scenic spots;
·
Details of local materials,
styles, streetscapes, etc.;
·
Prominent watercourses; and
·
Cultural and religious identity
11.3.6 The process of landscape characterisation draws on the information
gathered in the desk top and site survey and provides an analysis of the way in
which the elements including the identified landscape resources (LRs) interact
to create the character of the landscape. The Study Area is then divided into
broadly homogenous units of similar character which are called Landscape
Character Areas (LCAs).
11.3.7 The sensitivity of the individual LRs and LCAs to change is rated using
low, medium or high depending on the following factors:
·
Condition, quality and maturity
of the LRs / LCAs ;
·
Importance and rarity of
special landscape elements (rarity being of either local, regional, national or
global importance);
·
Ability of the LRs / LCAs to
accommodate change; and
·
Statutory or regulatory
requirements relating to the landscape including its resources.
11.3.8 The next stage of the assessment process is the identification of
the assessment of the magnitude of change (rated as negligible, small,
intermediate or large) arising from the implementation of the proposals and the
principal sources of impact based on the following factors:
·
Scale of the development and
proposed access road;
·
Compatibility of the project
with the surrounding landscape;
·
Duration of impacts (temporary
or permanent) under construction and operational phases; and,
·
Reversibility of change.
11.3.9 The degree of significance of landscape impact is derived from the
magnitude of change which the proposals will cause to the existing landscape
context and its ability to tolerate the change, i.e. its condition / quality
and sensitivity. This makes a comparison between the landscapes which would
have existed in the absence of the proposals with that predicted as a result of
the implementation of the proposals. The significance threshold for impacts to
LRs and LCAs is rated as significant, moderate, slight or negligible. The
impacts may be beneficial or adverse.
11.3.10 The significance threshold is derived from the following matrix:
|
Magnitude of Change caused
by Proposals
|
Large
|
Moderate
Impact
|
Moderate
/ Significant Impact
|
Significant
Impact
|
|
Intermediate
|
Slight
or Moderate Impact
|
Moderate
Impact
|
Moderate
or Significant Impact
|
|
Small
|
Slight
Impact
|
Slight
or Moderate Impact
|
Moderate
Impact
|
|
Negligible
|
Negligible
|
Negligible
|
Negligible
|
|
|
Low
|
Medium
|
High
|
|
|
Sensitivity
of Landscape to Change
|
11.3.11 The above matrix will apply in the assessment of the majority of
situations, however, in certain cases a deviation from this may occur, e.g. the
impact may be so major that a significant impact may occur to a LCA or LR with
a low sensitivity to change.
Tree Survey Methodology
11.3.12 To minimise conflicts with existing vegetation a preliminary tree
survey has been completed in broad accordance with ETWB TCW No. 3/2006 Management and Maintenance of Natural Vegetation and Landscape works
and Tree Preservation. This ‘broad brush’ tree survey
involves the identification of significant individual trees within the site
boundary. In accordance with normal practice the tree survey has been confined
to the site boundary as the trees beyond will not be affected by the proposed
works. The assessment of the identified landscape character areas also includes
a reference to the existence of trees within each area and their contribution
to the establishment of that character. The existing trees are categorised into
four tree groups according to their location and their potential conflict with
different parts of the proposed scheme.
Tree groups include trees inside the development area, wetland nature
reserve (at where bund to be removed), wet land reserve (at where bund to be
retained) and the alternative egretry. The survey includes approximate numbers
of trees, their species, sizes range, health condition, form, and amenity value
inside each tree group. This will allow the fine tuning of the detail design
for the proposed scheme and ensure that any significant trees, will where
possible, be protected during both the construction and operational phases of
the project.
Visual Baseline Review and Impact Assessment
11.3.13 The assessment of the potential visual impact of the scheme
comprises two distinct parts:
·
Baseline survey; and,
·
Visual impact assessment which
includes the identification of the sources of visual impact, and their
magnitude, that would be generated during construction and operational phases
of the proposed scheme; and, identification of the principal visual impacts
primarily in consideration of the degree of change to the baseline conditions.
11.3.14 The assessment area for the Visual Impact Assessment (VIA) in
accordance with the study brief, is defined by the 2-km Visual Envelope (VE)
which includes all areas from which the scheme proposals can be seen, or the
area forms the view shed formed by natural / manmade features such as existing
ridgelines, built development and for example areas of woodland / large
trees. Within the VE a number of Zones
of Visual Influence (ZVIs) are identified to demonstrate the visibility of
various aspects of the scheme proposals.
This is achieved through a combination of detailed walkover surveys, and
desk-top study of topographic maps and photographs, and preparation of
cross-sections to determine visibility of the improvement works from various
locations.
11.3.15 The baseline survey of all views towards the proposals is undertaken
by identifying:
·
The VE and ZVIs as has been
described above and may contain either wholly or partially within views. This
must also include indirect effects such as offsite construction activities;
and,
·
The visually sensitive
receivers (VSRs) within the visual envelope whose views will be affected by the
scheme.
11.3.16 The potential receivers are considered as four groups:
·
Views from residences – the most sensitive of receivers due to the high potential of
intrusion on the visual amenity and quality of life;
·
View from workplaces – less sensitive than above due to visual amenity being less
important within the work environment;
·
Views from recreational
landscapes – including all areas apart from the
above, e.g., public parks, recreation grounds, footpaths, cultural sites etc.
Sensitivity of this group depends on the length of stay and nature of activity,
e.g. sitting in a park as opposed to an active sporting pursuit; and
·
Views from public roads and
railways – including vehicle travellers with transitory
views.
11.3.17 The assessment of sensitivity is also based on the quality and
extent of the existing view. Therefore a view from a residential property,
which would normally be considered the most sensitive view, may be less so if
for example it is degraded by existing development or partially screened by
intervening visual obstacles such as existing vegetation. Factors affecting the
sensitivity of receivers for evaluation of visual impacts:
·
Value and quality of existing
views;
·
Availability and amenity of
alternative views;
·
Type of receiver population and
estimated number of affected receiver population;
·
Duration or frequency of view;
and,
·
Degree of visibility.
11.3.18 The location and direction of its view relative to the scheme also
influences the sensitivity of each group. Typical viewpoints from within each
of the visually sensitive groups are identified and their views described. Both
present and future (planned visually sensitive receivers (PVSRs) are
considered.
11.3.19 The factors affecting the magnitude of change for assessing the
visual impacts include the following:
·
Scale of the development and
proposed access road;
·
Compatibility of the project
with the surrounding landscape forming the view;
·
extent of visibility (level of
potential blockage of the view described in the text);
·
Viewing distance;
·
Duration of impacts under
construction and operational phases;
·
Reversibility of change ; and
·
Night glare effect.
11.3.20 Views available to the identified VSRs are rated according to their
sensitivity to change using low, medium or high. The magnitude of change to the
views will be classified as follows:
·
Large : e.g. the majority
of viewers affected / major change in view;
·
Intermediate: e.g. many viewers
affected / moderate change in view;
·
Small: e.g. few viewers
affected / minor change in view; and
·
Negligible: e.g. very few
viewers affected / no discernible change in view.
11.3.21 The significance threshold for visual impact is rated in a similar
fashion to the landscape impact, i.e. significant, moderate, slight and
negligible. The impacts may be beneficial or adverse.
11.3.22 Therefore the impact is derived from the magnitude of change which
the proposals will cause to the existing landscape context and its ability to
tolerate the change, i.e. its quality and sensitivity. The significance threshold
is derived from the following matrix:
|
Magnitude of Change caused
by Proposals
|
Large
|
Moderate
Impact
|
Moderate
/ Significant Impact
|
Significant
Impact
|
|
Intermediate
|
Slight
/ Moderate Impact
|
Moderate
Impact
|
Moderate
/ Significant Impact
|
|
Small
|
Slight
Impact
|
Slight
/ Moderate Impact
|
Moderate
Impact
|
|
Negligible
|
Negligible
|
Negligible
|
Negligible
|
|
|
Low
|
Medium
|
High
|
|
|
Sensitivity
of View to Change
|
11.3.23 The above matrix will apply in the assessment of the majority of
situations, however, in certain cases a deviation from this may occur, e.g. the
impact may be so major that a significant impact may occur to a view with a low
sensitivity to change.
11.3.24 Table 11‑1 below provides an explanation of the degree of impact
for both landscape and visual aspects of the project.
Table 11‑1 Degree
of Impact
|
Impact
|
Description
|
|
Significant
|
Adverse / beneficial impact where the
proposal would cause significant deterioration or improvement in existing
landscape quality or visual amenity.
|
|
Moderate
|
Adverse / beneficial impact where the
proposal would cause a noticeable deterioration or improvement in existing
landscape quality or visual amenity.
|
|
Slight
|
Adverse / beneficial impact where the
proposal would cause a barely perceptible deterioration or improvement in the
existing landscape quality or visual amenity.
|
|
Negligible
|
No discernible change in the existing
landscape quality or visual amenity.
|
Landscape Mitigation Measures
11.3.25 The purpose of mitigation is to avoid, reduce, and where possible
remedy or offset any adverse effects on the environment arising from the
proposed development. The ideal strategy for identifiable adverse impacts is
avoidance. If this is not possible, alternative strategies of reduction, remediation
and compensation should be explored.
11.3.26 Mitigation measures may be considered under two categories:
·
Primary mitigation measures
that intrinsically comprise part of the development design through an iterative
process. This form of mitigation is generally the most effective; and
·
Secondary mitigation measures
designed to specifically address the remaining (residual) adverse effects of
the final development process.
11.3.27 Primary mitigation measures form integrated mainstream components of
the project design focusing on the adoption of alternative designs or revisions
to the basic engineering and architectural design to prevent and/or minimise
adverse impacts including siting, access, layout, buildings and structures etc.
The design philosophy can also describe the benefits to the design of
alternative solutions, introduced to reduce potential adverse impacts, and
indicate how these have been addressed.
11.3.28 Secondary mitigation measures are specifically designed to mitigate
the adverse impacts of the final development and are considered in the
assessment of the landscape and visual impacts.
These may take the form of remedial measures such as colour and textural
treatment of building features; and compensatory measures such as the
implementation of landscape design measures (e.g. tree planting, creation of
new open space etc) to compensate for unavoidable adverse impacts and to
attempt to generate potentially beneficial long-term impacts.
Residual Impacts
11.3.29 The Residual impacts are those, which remain after the proposed
mitigation measures, have been implemented. This has been assessed both during
the construction period and during the design year which is often taken to be
10 to 15 years after the proposed scheme has been opened to normal operation
when the soft landscape mitigation measures are deemed to have reached a level
of maturity which allows them to perform their original design objectives.
11.3.30 The level of impact is derived from the magnitude of change which
the proposals will cause to the view which would have existed during this
period if the proposed scheme had not been constructed and its ability to
tolerate change, i.e. its quality and sensitivity taking into account the
beneficial effects of the proposed mitigation. The significance threshold is
derived from the matrices described separately above for the landscape and
visual impacts.
11.3.31 In accordance with Annex 10 of the EIAO-TM a final conclusion is
also made of the residual landscape and visual impacts attributable to the
proposed scheme. The degree of residual impact is considered in accordance with
the Residual Impact Significance Threshold Matrix in Table 11‑2 below.
Table 11‑2 Residual Impact
Significance Threshold Matrix
|
Residual Impact
|
Description
|
|
Beneficial
|
The project will complement the landscape
and visual character of its setting, will follow the relevant planning
objectives and will improve overall and visual quality.
|
|
Acceptable
|
There will be no significant effects on
the landscape and no significant visual effects caused by the appearance of
the project, or no interference with key views.
|
|
Acceptable with mitigation
|
There will be some adverse effects, but
these can be eliminated, reduced or offset to a large extent by specific
measures.
|
|
Unacceptable
|
The adverse affects are considered too
excessive and are would not be reduced to an acceptable level by mitigation.
|
|
Undetermined
|
Significant
adverse effects are likely but the extent to which they may occur or may be
mitigated cannot be determined from the study. Further detailed study will be
required for the specific effects in question.
|
Graphic Presentation of Mitigation Measures
11.3.32 In order to illustrate these landscape and visual impacts and to
demonstrate the effectiveness of the proposed landscape and visual mitigation
measures, photomontages at selected representative viewpoints, agreed with
Planning Department at the outset of the study, have been prepared to
illustrate:
·
Existing conditions;
·
Year 1 of Operation Phase without
Landscape Mitigation Measures;
·
Year 1 of Operation Phase with
Landscape Mitigation Measures; and,
·
Year 10 of Operation Phase with
Landscape Mitigation Measures.
Alternative Schemes
11.4.1 The process of selecting a preferred option for the development
considered a number of alternative options and designs based on the initial
findings of the various assessments not least the Ecological Impact Assessment
(EcoIA). This process is described in greater detail in Section 3 of this
report. These options included both alternative footprint locations and
alternative building height scenarios as shown on Figures 3-3 A to C and Figure 11-1A,11-1B, 11-1C and 11-1D.
Alternative Footprint Location
11.4.2 In order to avoid the flight path of birds to and from an egretry
identified during the EcoIA the building footprint for the development was
relocated approximately 150m
to the east. This relocation of the building footprint also serves to increase
the area of green buffer between the proposed residential development and the
existing high-rise development associated with Tin Shui Wai when viewed from
locations to the north. This is
important in maintaining the visual separation between the two developments
reinforcing the effect of a patchwork of development separated by existing
green features. It is also important to maintain as far as possible the green
edge to the fishpond area emphasising the naturalistic transition between
traditional fishpond and wooded hill slopes.
11.4.3 The development site is located on the southern periphery of the
traditional fishponds which characterise the low lying coastal plain of the Deep Bay
bisected by the Sham Chun and Shan Pui Rivers
to the northwest of the New
Territories. The
landscape character of this area is formed by a largely undeveloped flat
expanse of the fishponds bounded by the upright form of the surrounding hill
sides. The visual relationship between the fishponds, the mud flats and the
wooded hills sides is important to the landscape character of the area.
Alternative Building Height Profiles
11.4.4 In accordance to the requirements of Clause 3.5.9.5
(iv) under the Landscape and Visual Impact section of the Study Brief,
alternative building heights for the preferred footprint location, ranging from
10 storeys to 25 storeys, were assessed to examine the Development’s visual
compatibility with the surrounding rural setting. The three building height
scenarios assessed were:
·
Option 1A – all buildings not more than 18 storeys (8 blocks
of 14-18 storeys, 7 groups of low-rise buildings of 4-8 storeys including a 2
storey resident’s club house);
·
Option 1B – all buildings not
more than 15 storeys (9 blocks of 15 storeys, 7 groups of low-rise buildings of
4-10 storey including a 2 storey resident’s club house); and
·
Option 1C – all buildings not more than 10 storeys (29 blocks
of 7-10 storeys, 27 4-storey terrace houses and a two storey resident’s club
house).
Option 1A
11.4.5 Option 1A
(refer to Figure 11‑1A) adopts a medium-rise form utilising a stepped
building height profile (14 to 18 storeys) in response to the existing landform
and maximises visual permeability through the creation of view corridors and
voids within the building form allowing visual access to the hillsides beyond.
Option 1A is the only one of the
three options which is able to accommodate the voids within development façade
of each of the blocks. The view corridors form the location for the low-rise
buildings between the proposed medium-rise blocks. The proposed stepped edge to
the eastern and western periphery of the development resonates with the form of
the existing hills which rise from the flat plane of the Deep Bay
and its estuarine / maritime landscape. This is evident in the descending form
of the eastern and westernmost blocks from 18 to 14 storeys creating a stepped
effect. The
medium-rise building with stepped form and its development footprint allow the
minimisation of potential impacts to the existing landscape and visual
resources particularly in relation to the existing fishponds and hills which
form the backdrop.
Option 1B
11.4.6 The medium-rise form of Option 1B (15 storeys) incorporates blocks
of equal height (15 storeys) and will not incorporate the stepped building
height profile adopted for Option 1A
(refer to Figure 11-1A).
Although the utilisation of a constant height (15 storeys) for the individual
blocks will not create the same dynamic relationship in terms of the building
form with the existing landscape context which exists with Option 1A. Similar to option 1A the creation of a permeable and
responsive building form preserves, as far as possible, the visual relationship
between the existing estuarine landscape and its setting of wooded hillsides.
Sharing the same residential development site area as Option 1A the direct loss of landscape resources
has been minimised as far as possible.
Option 1C
11.4.7 Option 1C (7 to
10 storeys) although when viewed from a distance more akin to the traditional
vernacular village architecture of the region in terms of its form the proposed
blocks are considerably higher than the traditional village houses (refer to
Figure 11-1A). The development
does not respond to the visual dynamics of the existing landscape context. In
addition when viewed from the north the development visually coalesces to form
a wall with no visual access to the landscape beyond. Of the three options this
development uses the most extensive area to accommodate the built development
and so has a corresponding smaller area available for soft landscape measures.
Selection of a Preferred Option
11.4.8 The selection of the preferred option requires a balanced view of
the environmental factors particularly those relating to the ecology of the
Study Area which is considered in Section 3 above. The ecological impact assessment
determined the location of the footprint for the development however the
building height profile for the preferred option also considered the potential
landscape and visual impacts. A comparison of the three options is shown on
Table 11-3.
11.4.9 Of the three development forms options 1A and 1B were considered preferable from a landscape
and visual impact perspective. This was mainly due to the reduced number of
medium-rise blocks providing view corridors to maximise the degree of visual
access which these options allow to wooded hill sides to the south of the
development site thus preserving the link between the fishponds and their
landscape context. The building profile of option 1A also responds to the form of the existing
topography to a greater degree than the other alternative option 1C creating a development which is both
visually interesting and visually permeable. This includes the incorporation of
voids within each of the blocks. The height profile of options 1A and 1B mirror the line of the ridgeline
to the south looking from the site boundary in the north as illustrated on Figure 11‑1A creating a dynamic relationship with the existing
landscape context something which few other developments in the local area
achieve.
11.4.10 In addition, for both Options 1A
and 1B the smaller building clusters and their non-linear layout create
intimate landscaped courtyards between buildings and minimise the wall effect
which could potentially arise from the development proposals which form the basis
of Option 1C in
responding to the surrounding rural context.
11.4.11 The use of the varied building height and form of the overall
development is also in tune with Planning Department’s guidance as detailed in
the Urban Design Guidelines for Hong Kong (November 2002). The height issue is less of a concern in
terms of the buildings relationship to the existing ridgeline as for most views
the proposals leave the ridgeline visually intact.
11.4.12 Following the selection of the preferred options 1A and 1B the design for each option was
further refined in response to an iterative assessment process with the
selection of the proposed southern development access in preference to the
original western development access which skirted the fishpond area to the
north of the development site. The western access road would have led to the
further loss of the fishponds an important landscape resource, the loss of
physical and visual integrity of the remaining fishpond area, and the loss of
the tranquillity which forms an important characteristic of the landscape of
the Study Area. Whereas the southern development access will follow the
alignment of the existing Fuk Shun
Street through Tai Tseng Wai minimising potential
impacts to the existing landscape context of the Study Area.
Table 11‑3 Alternative Schemes Comparison
|
Evaluation Criteria
|
Option 1A
|
Option 1B
|
Option 1C
|
|
Scheme
Description
|
|
|
|
|
Residential Site Area
|
40,000m2
|
40,000m2
|
60,000m2
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Site Coverage
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32.8%
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34.4%
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34%
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Number of Building Blocks
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8 blocks with 14-18 storeys (each block
adopting a stepped height profile), 7 groups of low-rise buildings of 4-8
storeys including a 2 storey resident’s club house (to maximise the size of
the visual corridor between blocks).
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9 blocks with 15 storeys, 7 groups of
low-rise buildings of 4-10 storey including a two storey resident’s club
house (to maximise the size of the visual corridor between blocks).
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29 blocks with 7-10 storeys, 27 4-storey
terrace houses and a 2 storey resident’s club
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Number of Storeys
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All buildings not more than 18 storeys
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All buildings not more than 15 storeys
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All buildings not more than 10 storeys
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Building Orientation
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Zigzag
Layout
Medium-rise buildings distributed in a
zigzag arrangement with low-rise building groups between the proposed
medium-rise blocks.
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Zigzag Layout
Medium-rise buildings distributed in a
zigzag arrangement with low-rise building groups between the proposed medium-rise blocks.
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Linear Layout
7-10 storeys buildings evenly distributed
along the eastern side of the boundary and low-rise terrace houses
concentrated along the western edge.
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View Corridors
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8 blocks with 7 wider view corridors
ranging in width from 29.4m
to 31.3m.
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9 blocks with 8 narrower view corridors ranging in width from 15.6m to 26.2m.
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Continuous building form with no view
corridors. The low-rise approach involves the use of an extensive, narrow
site. The form of the site does not allow for the grouping of these low-rise
buildings to create view corridors.
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Visual Mass of Structure and Permeability
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Maximises
visual permeability through the creation of view corridors allowing visual
access to the hillsides beyond. The view corridors are formed through the
location of the low-rise building groups between the proposed medium-rise
blocks. Option 1A
also incorporates significant voids within the structure of each of the
proposed blocks further enhancing visual permeability. These voids will
contain sky gardens. Option IA is therefore more permeable than Options 1B
and 1C due the size of the
proposed view corridors.
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Maximises
visual permeability through the creation of view corridors allowing visual
access to the hillsides beyond. The view corridors are formed through the
location of the low-rise building groups between the proposed medium-rise
blocks.
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Although
visually more akin to the traditional vernacular village architecture of the
region in terms of its form when viewed from a distance, the proposed blocks
are considerably higher than the traditional village houses. The eastern
building cluster the blocks also forms a single visual entity negating the
principle of adopting a permeable edge.
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Building Profile
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Each medium-rise block has a stepped
height profile from 14 to 18 storeys in three steps. This stepped approach is
designed to provide a better sense of integration with the surrounding
landscape context and a more visually interesting built form. Due to the
orientation of the blocks the stepping is apparent at the eastern and western
ends of the development and in the interface with the pond area to the north
of the development site. The proposed development will also incorporate seven
groups of low-rise buildings with four clusters located along the south
eastern boundary of the site to create a more subtle transition between the proposed
development and the village houses to the south. The other three groups
including the 2 storey resident’s club will be located adjacent to the noth
west potion of the site boundary will have similar effect with the transition
to the proposed marsh area.
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The roofline is maintained at a
consistent height of 15 storeys. This produces a flat roofline which appears
visually incongruous when viewed against the organic form of the natural
landscape backdrop. This
development option will also incorporate five groups of low-rise buildings
located along the south eastern boundary and two groups including the 2
storey resident’s club located adjacent to the noth west potion of the site
boundary.
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The height of the blocks range from 7 to
10 storeys with the lower blocks located to the east and west of the
development to create less abrupt building edge and improve its integration
within the landscape. However this stepped height profile is not readily
apparent in many views due to the proximity of the blocks to one another and
the viewing distances involved. This option will incorporate 4 storey high
terraced housing and the 2 storey resident’s club along the north western
boundary of the site adjacent to the proposed marshland area. Again these
structures will create a limited stepped effect although when viewed from the
majority of view points the blocks will visually merge with the terraced
housing due largely to the viewing distance.
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Landscape
Impacts
|
|
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Existing Trees
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Total number of trees: 665
Retained trees: 238 (36%)
Transplanted trees: 28 (4%)
Felled trees: 399 (60%)
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Total number of trees: 665
Retained trees: 238 (36%)
Transplanted trees: 28 (4%)
Felled trees: 399 (60%)
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Total number of trees: 665
Retained trees: 231 (35%)
Transplanted trees: 28 (4%)
Felled trees: 406 (61%)
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Landscape Resources
|
Main impacts:
LR 1 – Landform: approx. 4.6
ha
LR 8 – Fishponds: approx. 4 ha
LR 10 – Watercourses: 800m2
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Main impacts:
LR 1 – Landform: approx. 4.6
ha
LR 8 – Fishponds: approx. 4 ha
LR 10 – Watercourses: 800m2
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Main impacts:
LR 1 – Landform: approx. 4.6
ha
LR 8 – Fishponds: approx. 6 ha
LR 10 – Watercourses: 800m2
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Landscape Character
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Main direct impacts:
Fishponds (AGR 2): Moderate adverse impact
(Due to the loss of area and the indirect impacts on the character of
the remaining fishponds).
Indirect impacts:
Kai Shan
Range (NUA 1): Moderate adverse
and the settlements of the Ng Uk Tsuen Village Cluster (V1): Slight Adverse.
Other impacts largely negligible due to the remoteness of the site from
the identified character areas (Hong Kong
Wetland Park
(OS 1), Yuen Long Industrial Estate (ICA
1) and Kam Tin and Shan Pui River Estuaries, and the Tin Shui Wai Drainage
Channel (EL1)).
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Main direct impacts:
Fishponds (AGR 2): Moderate adverse impact
(Due to the loss of area and the indirect impacts on the character of
the remaining fishponds).
Indirect impacts:
Kai Shan
Range (NUA 1): Moderate adverse
and the settlements of the Ng Uk Tsuen Village Cluster (V1): Slight Adverse.
Other impacts largely negligible due to the remoteness of the site
from the identified character areas (Hong Kong
Wetland Park
(OS 1), Yuen Long Industrial Estate (ICA
1) and Kam Tin and Shan Pui River Estuaries, and the Tin Shui Wai Drainage
Channel (EL1)).
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Main direct impacts:
Fishponds (AGR 2): Significant adverse impact
(Due to the truncation of the fishponds from the wooded hill sides
which form their setting, the loss of area and the indirect impacts on the
character of the remaining fishponds).
Indirect impacts:
Kai Shan
Range (NUA 1): Moderate adverse
and the settlements of the Ng Uk Tsuen Village Cluster (V1): Slight Adverse..
Other impacts largely negligible due to the remoteness of the site
from the identified character areas (Hong Kong
Wetland Park
(OS 1), Yuen Long Industrial Estate (ICA
1) and Kam Tin and Shan Pui River Estuaries, and the Tin Shui Wai Drainage
Channel (EL1)).
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Visual Impacts
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Main impacts:
The residents of Ng Uk Tsuen (VSR 6) and Shing Uk Tsuen (VSR 7)
(approximately 10 houses in each case) living at the northern periphery of
the villages with windows facing north towards the development site: Moderate
to significant adverse.
For other residents of the villages, pedestrians within open spaces
and vehicle travellers the impacts are likely to be slight to moderate
adverse due to the screening effect of adjacent village houses, the angle and
viewing distance, and the proximity of existing vegetation.
Slight / moderate adverse impact: Long Ping Estate (VSR 9) and Tin
Tsz Estate (VSR 10), Whereas the other VSRs including Tin Shui Wai (VSR 1),
Tsim Bei Tsui (VSR 2), Fairview Park (VSR 4), Tai Sang Wai (VSR 5), Kai Shan
(VSR 8) Kenwood Court (VSR 11), Tin Yuet Estate (VSR 12), Vianni Cove (VSR
14) and Grandeur Terrace (VSR 15) would experience a moderate adverse impact
mitigated to an extent by the expansive nature of the existing views, the
viewing angle and distance, and the design and disposition of the proposed
scheme.
Slight adverse: Mong Tseng Wai (VSR 3), due to the low lying nature
of these VSRs, the screening effect of the intervening landform and
vegetation, and the viewing angle and distance.
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Main impacts:
The residents of Ng Uk Tsuen (VSR 6) and Shing Uk Tsuen (VSR 7)
(approximately 10 houses in each case) living at the northern periphery of
the villages with windows facing north towards the development site: Moderate
to significant adverse.
For other residents of the villages, pedestrians within open spaces
and vehicle travellers the impacts are likely to be slight adverse due to the
screening effect of adjacent village houses, the angle and viewing distance,
and the proximity of existing vegetation.
Slight / moderate adverse impact: Long Ping Estate (VSR 9) and Tin
Tsz Estate (VSR 10), Whereas the other VSRs including Tin Shui Wai (VSR 1),
Tsim Bei Tsui (VSR 2), Fairview Park (VSR 4), Tai Sang Wai (VSR 5), Kai Shan
(VSR 8) Kenwood Court (VSR 11), Tin Yuet Estate (VSR 12), Vianni Cove (VSR
14) and Grandeur Terrace (VSR 15) would experience a moderate adverse impact
mitigated to an extent by the expansive nature of the existing views, the
viewing angle and distance, and the design and disposition of the proposed
scheme.
Slight adverse: Mong Tseng Wai (VSR 3), due to the low lying nature
of these VSRs, the screening effect of the intervening landform and
vegetation, and the viewing angle and distance.
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Main impacts:
The residents of Ng Uk Tsuen (VSR 6) and Shing Uk Tsuen (VSR 7)
(approximately 10 houses in each case) living at the northern periphery of
the villages with windows facing north towards the development site: Moderate
to significant adverse.
For other residents of the villages, pedestrians within open spaces
and vehicle travellers the impacts are likely to be slight adverse to
negligible due to the reduced height of the proposed development.
Slight / moderate adverse impact: Long Ping Estate (VSR 9) and Tin
Tsz Estate (VSR 10),
Whereas the other VSRs including Tin Shui Wai (VSR 1), Tsim Bei Tsui
(VSR 2), Fairview Park (VSR 4), Tai Sang Wai (VSR 5), Kai Shan (VSR 8)
Kenwood Court (VSR 11), Tin Yuet Estate (VSR 12), Vianni Cove (VSR 14) and
Grandeur Terrace (VSR 15) would experience a moderate adverse impact
mitigated to an extent by the expansive nature of the existing views, the
viewing angle and distance, and the design and disposition of the proposed
scheme. The visual impacts for Tsim Bei Tsui (VSR 2) more pronounced due to
the large site area.
Slight adverse: Mong Tseng Wai (VSR 3), due to the low lying nature
of these VSRs, the screening effect of the intervening landform and
vegetation, and the viewing angle and distance.
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Description of Preferred Options 1A and 1B
11.4.13
Option 1A
11.4.14 The proposed scheme consists of eight blocks of maximum 18 storeys,
and 7 groups of low-rise buildings (4-8 storeys) including a two storey club
house. It involves a minimum landtake for residential development so as to
reduce the disturbance to the preserved fish ponds. The low-rise buildings are arranged in the
space between the medium-rise building clusters creating a more subtle
transition between the development and the surrounding landscape particularly
the existing fishponds to the north.
These low-rise buildings are arranged to have irregular frontages
creating visual interest. The medium-rise blocks are arranged with four on an
east-west axis and four on a north-south axis designed to maximise the visual
permeability of the development when viewed from the main concentrations of
VSRs from the west (Tin Shui Wai) and from the east (developments such as the
Fairview Park). With the low-rise
buildings located between these clusters and a clubhouse in the central portion
of the site. With this arrangement seven view corridors are created between the
medium-rise building blocks. The building height profile for the proposed medium-rise
blocks is designed to rise from 14 to 18 floors in each block designed to
create stepped building profile for each. The lower portion of each is arranged
to face the wetland to the north and hence soften the transition from the
existing fishponds to the proposed development.
11.4.15 The proposed view corridors bisect the medium-rise development to
create seven distinct medium-rise building blocks with 7 groups of low-rise
buildings sitting in between allowing visual access to the landscape of wooded
hillsides to the south of the proposed development. These view corridors are
orientated to provide maximum benefit in views from the main concentrations of
visually sensitive receivers particularly when viewed from the northern part of
Tin Shui Wai. In addition to containing the proposed low-rise buildings these
view corridors also contain the key landscape features such as the proposed
clubhouse, children’s playgrounds and gardens. The car park will be located in
basement in order to minimise potential adverse landscape and visual impacts,
and maximise the area available for landscaping.
11.4.16 Another innovative design feature of Option 1A is the incorporation of voids within each of the
blocks which serve to further enhance the visual permeability of the scheme.
These voids are arranged to create an architectural rhythm in the treatment of
the facades and minimise the visual mass of the development. Each of the voids
would accommodate a sky garden increasing the open space available to future
residents and the area of visible greenery.
11.4.17 Access to the site is provided by the proposed Southern Development
Access which utilises the alignment of an existing Fuk Shun Street passing through the
villages of Tai Tseng Wai and Shing Uk Tsuen. Fuk Shun Street will be widened within
the existing landtake to a standard 7.3m
single 2-lane public road with 2m
wide footpath on both sides of the carriageway. The Southern Development Access
will also minimise the potential disturbance from a landscape and visual
perspective preserving the tranquillity of the fishpond area to the north of
the development site.
11.4.18 Option 1B
11.4.19 Option 1B shares many of the characteristics of Option 1A in terms of the design approach to the
building disposition and architectural form. The proposed scheme consists of
nine blocks of 15 storeys, 7 groups of low-rise buildings (4-10 storeys)
including a residents’club house. This option shares the same landtake as
Option 1A so as to reduce the
disturbance to the preserved fish ponds.
Again the low-rise buildings are arranged in the space between the
medium-rise buildings creating a more subtle transition between the development
and the surrounding landscape particularly the existing fishponds to the
north. These low-rise buildings are
arranged to have irregular frontages creating visual interest. The medium-rise
blocks are arranged with four on an east-west axis and five on a north-south
axis designed to maximise the visual permeability of the development when
viewed from the main concentrations of VSRs from the west (Tin Shui Wai) and
from the east (developments such as the Fairview Park). With the low-rise buildings located between
the medium-rise blocks and a clubhouse in the central portion of the site. With
this arrangement eight view corridors are created between the medium-rise
building blocks. The proposed limitation
of the building heights to 15 storeys serves to maximise the visual access to
the landscape to the south of the development site including the wooded hillsides
however the addition of an additional block compared to Option 1A serves to reduce the effective width
of the view corridors and therefore slightly reduce the visual permeability of
the development when viewed from the east and west. Option 1B would adopt the
same proposals for the Southern Development Access as Option 1A.
11.5.1 A review of the existing planning studies and documents has been
undertaken to gain an insight into the planned role of the site, its context
and to help determine the projects fit into the wider landscape context. The
assessment does not consider all of the areas zoned on the OZP only those
affected by the proposals, the location of these areas are shown on Figure
11-8. The predicted impacts arising from Options 1A and 1B are considered similar due to their similar
architectural characteristics, shared footprint and location. This review for
Options 1A and 1B considered the
following aspects of the identified planning designations:
·
Zoning areas which would be
physically affected by the proposals, that is where the implementation of the
proposal works would lead to the actual loss of an area;
·
The potential degradation of
the landscape setting of an area which might effect the viability of it’s
landscape planning designation but not result in a loss of zoning area;
·
The visual amenity enjoyed by
future residents or users; and,
·
The general fit of the
proposals into this future landscape.
11.5.2 A review of the Final Report of Study on the Ecological Value of
Fish Ponds in Deep Bay Area is contained in Section 11.6 formed part of the
landscape planning control review to gain an insight into the guidelines for
the formulation of master layout plan within the study area. The assessment
covers areas shown on the following Outline Zoning Plans:
·
S/YL-LFS/7, Lau Fau Shan and
Tsim Bei Tsui;
·
S/TSW/11 Tin Shui Wai; and
·
S/YL-PS/11 Ping Shan.
·
S/YL/17 Yuen Long.
11.5.3 This review has found that the following impacts on identified
planning designations:
·
Areas that would be physically
affected whereby the implementation of the development proposals would lead to
the actual loss of area. These include approximately 4 hectares of the existing
Comprehensive Development and Wetland Enhancement Area. Although the proposals are in accordance with
the planned use for this area there would be some loss of visual amenity and a
slight degradation of landscape character as a result of the proposals. However
the development proposals have sought to minimise the potential landscape and
visual impact by locating the development on the southern periphery of the
site. In addition some 76.1 hectares of fishponds would be transformed into a
Wetland Nature Reserve thus ensuring that the area is both visually enhanced
and safeguarded as a landscape resource.
·
The assessment found no areas
where the proposed development would lead indirectly to a degradation of the
landscape setting of an area thus affecting its viability in terms of being a
landscape planning designation.
·
There are two main areas where
the proposed development would affect the visual amenity enjoyed by future
residents or users. These are shown on Tin Shui Wai OZP, S/TSW/11, and include the proposed residential
development for the north eastern side of Tin Shui Wai including the Area 104
designated as R(B)1 Zone. The residents of developments on the eastern
periphery of these areas would be the only ones affected by the development
proposals although low-level views would be largely screened by the existing
vegetation on the existing fishpond bunds and the proposed Open Space located
at Area 117 and 120. In addition more elevated views would be affected for the
future residents at Area 103 which is designated as R(A) Zone intended to allow
high density residential development, for residents on the eastern side of this
development would overlook the proposed development site although at a viewing
distance of some 1500m.
·
The proposals will not have a
direct impact on the existing Hong Kong Wetland Park (HKWP) where zoned “Other
Specific Uses” in the OZP as presented in Table 11-4. The implementation of the
proposed Wetland Nature Reserve (WNR) including the proposed marsh habitat will
provide an extension of the HKWP.
·
The proposal will not have
impact on the existing Yuen Long Industrial Estate where zoned as “Other
Specific Uses” and other zoning area within Yuen Long OZP, S/YL/17, regarding to the locations of these zoning
areas are separated by “Village Type Development” and “Green Belt” zones
contained within Ping Shan OZP, S/YL-PS/11 from the proposed development.
11.5.4 Given the above summary of impact on planning control framework on
and adjacent to the development site and detailed review in Table 11-4 below,
the proposed development sited within the area zoned “Other Specific Uses
(Comprehensive Development and Wetland Enhancement Area)”, “OU(CDWEA)”,
contained within Lau Fau Shan and Tsim Bei Tsui OZP, S/YL-LFS/7, comply with
the planning intention for this zoning through redevelopment of the site with
conservation objectives and positive measures to enhance the ecological value
and functions of the existing fish ponds and wetland and will generally fit
within the future landscape planning framework as represented by the OZPs,
hence no amendment to the published land use plans is required. Although the proposals
would therefore not have an adverse impact being largely compatible with the
planning intention for the area and the planned landuses in the adjourning
areas and would fit into the outlook of the remaining rural landscape context
in Deep Bay Area surrounding by Tin Siu
Wai high-rise developments to the west, village and Yuen Long
industrial developments to the south, Section 16 planning application is still
required to permit the proposed development in accordance with the requirement
under OZP at later stage.
Table 11‑4 Review of Existing Planning and
Development Control Framework
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Land Use Zonings
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Landscape Planning, Design and
Conservation Intention of Zoning
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Approx. Area Affected by the Proposals
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Potential Impact on Zoning Areas
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Mitigation Measures and Future Outlook of
the Area with the Development Proposal
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Outline Zoning Plan number S/YL-LFS/7 – Lau Fau Shan
and Tsim Bei Tsui
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1.
Comprehensive
Development and Wetland Enhancement Area (OU)
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Land
zoned for this purpose is to have no new development except development
and/or redevelopment with conservation objectives and positive measures to
enhance the ecological value and functions of the existing fish ponds and
wetland. Development should be in the form of a comprehensive development
scheme with minimum pond filling.
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The whole designated site.
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The
proposed development will be in accordance with the planning intention of
this zone with the potential impacts being minimised as far as possible
through the siting and design of the development proposals required only 4 Ha. of the whole zoning area. The
proposed WNR on the rest of the zoning area will also enhance the existing
landscape to the north of the development area.
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Primary mitigation includes the responsive siting and extent of
footprint for the proposed development. Secondary mitigation includes design
of residential building, the provision of WNR, landscape buffer planting,
compensatory and new amenity planting and restoration of access road
landscape. Given the full establishment of the above mitigation measures the
development proposals contained within this zone are compatible to the
planning intention in principle and fairly integrated with the wetland and
village landscape context.
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2.
Conservation Areas (CA)
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The
planning intention of this zone is to conserve the ecological value of the
fishponds which form an integral part of the wetland ecosystem in the Deep Bay
area.
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No actual loss but
indirect impacts.
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The main areas indirectly affected by the
proposed development are located to the south west, along the southern
periphery of the OU (CDWEA) described above and to the east of the
development site. However the design and siting of the proposed development
including the access road has sought to avoid these areas and so any impacts
will be indirect and based on impacts to their landscape context.
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Primary
mitigation includes the responsive siting and extent of footprint for the
proposed development. Secondary mitigation includes design of residential
building, the provision of WNR, landscape buffer planting, compensatory and
new amenity planting and restoration of access road landscape. Given no
direct impact on this zoning area, the full establishment of the above
mitigation measures and providing a better integration between the
development site and the conservation area, the development proposals are
compatible to the planning intention of this zoning and fairly integrated
with the wetland landscape context.
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Outline Zoning Plan number S/YL-PS/11 – Ping Shan
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3.
Village Type Development (V)
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This area encompasses the villages of Ng Uk,
Tai Tseng Wai and Shing Uk Tsuen and is located on the saddle between two
summits of the Kai Shan range immediately to the south of the proposed
development site. The planning intention of this zone is to designate both
existing and recognised villages and areas of land considered suitable for
village expansion.
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No actual loss but
indirect impacts.
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The proposed development would
not infringe upon this area and despite its proximity would not have a
significant effect on the landscape setting of these settlements.
The Southern Development
Access would utilise the existing footprint of Fok Shun Road and so would not cause
any additional impacts on the village.
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Primary mitigation includes the responsive siting and extent of
footprint for the proposed development. Secondary mitigation includes design
of residential building, the provision of WNR, landscape buffer planting,
compensatory and new amenity planting and restoration of access road
landscape. Given the full establishment of the above mitigation measures the
development proposals are compatible to the planning intention of its
adjacent village and fairly integrated with the village landscape context.
-
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4. Green Belt (GB)
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The
planning intention of this zone is to define the limits of urban and suburban
development areas by natural features, to contain urban sprawl as well as to
provide passive recreational outlets. The two main area of Green Belt
adjacent to the proposed development site are located to the north and
northeast of Kai Shan.
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No actual loss but
indirect impacts.
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The areas will not be physically affected
by the proposals although there may be some indirect impacts on their landscape
setting due to the proximity of the proposed development.
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Primary mitigation includes the responsive siting and extent of
footprint for the proposed development. Secondary mitigation includes design
of residential building, the provision of WNR, landscape buffer planting,
compensatory and new amenity planting and restoration of access road
landscape. Given the full establishment of the above mitigation measures the
development proposals are compatible to the planning intention of its
adjacent green belt and integrated with the adjacent woodland landscape
context.
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Outline Zoning Plan number S/TSW/10 – Tin Shui Wai
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5.
Other Specified Uses (Hong Kong Wetland
Park) (OU)
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The
Hong Kong Wetland Park (HKWP) is proposed as replacement habitat for the
wetland lost from the engineering works for the residential zone and to act
as a buffer to minimise human disturbance to the adjacent ecologically
sensitive areas.
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No actual loss but
indirect impacts.
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The development proposals will not have a
direct impact upon this area. The implementation of the proposed WNR
including the proposed marsh habitat will provide an extension of the Hong Kong Wetland Park
particularly in views from the upper floors of the proposed high-rise
residential development on the western periphery of Tin Shui Wai.
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Primary mitigation includes the responsive siting and extent of
footprint for the proposed development. Secondary mitigation includes design
of residential building, the provision of WNR, landscape buffer planting,
compensatory and new amenity planting and restoration of access road
landscape. Given the full establishment of the above mitigation measures
providing better integration with its adjacent zoning area reserved for park
and wetland reserve, the development proposals are compatible to the planning
intention of its adjacent zoning area and integrated with the adjacent
wetland conservation landscape context.
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6.
Comprehensive Development Area (CDA)
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Site
115 to the northwest of the proposed development area is intended for lower
density development taking into account their proximity to the Hong Kong Wetland Park
and the conservation areas to the northeast.
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No actual loss but
indirect impacts.
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The development proposals would have no
direct impact on this area the proposals would have an indirect impact on the
visual amenity for residents on the eastern periphery of the area.
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Primary mitigation includes the responsive siting and extent of
footprint for the proposed development. Secondary mitigation includes design
of residential building, the provision of WNR, landscape buffer planting,
compensatory and new amenity planting and restoration of access road
landscape. Given the full establishment of the above mitigation measures the
development proposals are compatible to the planning intention for lower
density development within this zone, the provision of WNR enhance the visual
amenity extending from HK wetland Park in the foreground of the local visual
context, and hence making the proposal development integrated with the future
low-rise residential landscape context.
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7.
Residential (B) 1 (R(B))
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These
areas (104) are zoned for medium-density private development
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No actual loss but
indirect impacts.
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The development proposals would have no
direct impact on this area the proposals would have an indirect impact on the
visual amenity for residents on the eastern periphery of the area. Visual amenity from future residents of the
eastern periphery in this area towards the HK Wetland Park and fishpond area
would be affected by the development proposals although low-level views would
be largely screened by the existing vegetation on the existing fishpond bunds
and that proposed Open Space for area 120.
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Primary mitigation includes the responsive siting and extent of
footprint for the proposed development. Secondary mitigation includes design
of residential building, the provision of WNR, landscape buffer planting,
compensatory and new amenity planting and restoration of access road
landscape. Given the full establishment of the above mitigation measures
providing a better integration between the development and adjacent wetland
areas, the development proposals are compatible to the planning intention for
adjacent medium density residential development within this zoning area and
integrated with the future residential landscape context.
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8.
Residential (A) (R(A))
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This
area on the north eastern side of the Tin Shui Wai New Town (Area 103) is
intended as a high density development.
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No actual loss but
indirect impacts.
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The development proposals would have no
direct impact on this area the proposals would have an indirect impact on the
visual amenity for residents of the area. Future residents are likely to have
elevated views of the development proposals although it would form a relatively
small component of the overall view available and at a viewing distance of
some 1200m both factors
which will minimise potential impacts.
|
Primary mitigation includes the responsive siting and extent of
footprint for the proposed development. Secondary mitigation includes design
of residential building, the provision of WNR, landscape buffer planting,
compensatory and new amenity planting and restoration of access road
landscape. Given the full establishment of the above mitigation measures
providing a better integration between the development and adjacent wetland
areas, the development proposals are compatible to the planning intention for
adjacent high density residential development within this zoning area and
integrated with the future residential landscape context.
|
|
Key:
Sensitivity of Resource (Sens): Low,
Medium or High
Magnitude of Change (Mag): Negligible,
Small, Intermediate or Large
Impact Significance
Threshold: Potential impacts on the existing and planned landscape
planning and development control framework arising from the proposals
Significance Threshold: Negligible,
Slight, Moderate and Significant (Adverse or Beneficial)
Con: Construction phase impacts
Oper: Operational phase impact
11.6.1 A review of the Final Report of Study on the Ecological Value of
Fish Ponds in Deep Bay Area has been undertaken to gain an insight into the
guidelines for the formulation of master layout plan within the study area.
Although these guidelines are indicative only and should not be taken as rigid
requirement, they address specifically the interface treatment between the new
wetland areas to be restored or created and the development area within the
overall development site. Guidelines suggested in the study include the
following:
·
Definition of the development
site, the development area, and the wetland restoration /creation area;
·
Building Massing and Height
o
The overall site planning
should reflect an increase in general height of buildings and structures away
from the wetland restoration/creation area;
o
The maximum height of any
building should be compatible with the character of the immediate surrounding
area;
o
A cluster concept should be
adopted as the overall site planning approach;
·
Vehicular circulation
o
If possible, all vehicular
circulation and space should be located away from the wetland restoration
/creation area;
·
Landscape Design
o
The landscape material to be
used within the wetland restoration /creation area should follow the wetland
restoration/creation proposals to be approved by the Town Planning Board with
input from the Agriculture, Fisheries and Conservation Department;
o
Natives species should be
widely used inside the wetland restoration/creation area, particularly along
the interface with the adjourning wetland;
o
Landscape buffers should be
considered to be established along the edge of the wetland to be restored or
created;
·
Glare and Noise
o
The overall site planning
should prevent unnecessary noise and glare impacting on the wetland. This could
be achieved by building orientation, siting as well as the planning and design
of exterior lighting; and
·
Drainage
o
Treatment of the drainage
proposal will have significant impact on the wetland to be created. The planning
and design concept for the new wetland, especially the hydrological regime
should be incorporated in to the drainage proposal.
11.6.2 The preferred development schemes for Options 1A and 1B have taken into account of the above
planning guidelines through the application of following measures:
l
A
responsive site planning including the siting of the buildings at the southern
edge of the boundary adjacent to the existing villages;
l
Maximising
the visual permeability through the creation of view corridors allowing visual
access to the hillsides beyond and the location of the low-rise buildings
between the proposed medium-rise blocks;
l
Use
of a stepped edge profile for the blocks in Option 1A designed to soften the transition between the flat
coastal plain and the proposed scheme;
l
Minimising
the proposed visual prominence of the proposed development through the
minimisation of the proposed building height for both options (Option 1A maximum 18 storeys and Option 1B
maximum 15 storeys); and
l
Creation
of a new marsh habitat immediately adjacent to the proposed tree and shrub
planting at northern edge of the development which together serve as a
landscape buffer to the wetland enhancement area.
11.6.3 The preferred schemes (Options 1A
and 1B) and their landscape proposals therefore fit into the wider landscape
context and the landscape of the wetland enhancement scheme. The landscape
design proposals for both options are further discussed in Section 11.10.
Baseline Conditions
11.7.1 The baseline review of the existing landscape establishes broad
characteristics, identifies landscape resources, and then provides a
characterisation and evaluation of the identified Landscape Character Areas
(LCAs).
11.7.2 Figure 11‑2 shows the existing LRs found within the Study
Area and Figure 11-4 shows the extent of identified LCAs.
Figure 11-5A and
B illustrate the LCAs with site photographs.
Topography
11.7.3 The topography of the Study Area is characterised by a series of
interconnected river valleys leading to the flat coastal landscape of Deep Bay
and the estuarine landscape of the Shan Pui and Shan Chun Rivers. This
landscape is punctuated by the uplands associated with the Lau Fau Shan
peninsular and the Kai Shan range. The valleys are contained by the steep sided
uplands of the Lam Tsuen and Tai
Lam Country
Parks. To the north of
the development site the landscape extends over traditional fishponds to the
tidal mudflats of the mouth of the Shan
Pui River
and Deep Bay. To the east the traditional
fishponds of the Lut Chau and Nam Sang Wai areas are bounded by a flat
agricultural plain east of Castle
Peak Road and the uplands of the Lam Tsuen Country Park
rising to the summit of Kai Kung Leng at 585mPD. To the south of the
development area the landscape is punctuated by the twin summits of the Kai
Shan range on a north-south axis rising to a summit of approximately 121mPD
backed by the uplands of the Tai
Lam Country
Park rising ultimately to
approximately 507mPD. To the west of development site is situated the large
reclaimed development platform for the Tin Shui Wai development leading to the
agricultural area of Ha Tsuen and the summit of Yuen Tau Shan at approximately
375mPD.
Vegetation
11.7.4 The vegetation of the Study Area has for the large part been
considerably modified by human activity and so the existing pattern of
vegetation represents a variation from the natural regime or climax vegetation,
which would naturally occur in this area. This reflects the historical
development of the area particularly in agricultural practices including the
extensive fish pond areas, village development and more recently the
development of new urban areas such as Tin Shui Wai. The main vegetation pattern is characterised
by three main vegetation types associated with the traditional fishpond areas,
agricultural fields and wooded hill slopes which punctuate the coastal plain.
However the landscape of the tidal mudflats and its associated mangrove forests
represents one of the few natural landscapes in Hong Kong.
The main vegetation types are described in greater detail as part of the
landscape resources section below.
11.7.5 Figure 11‑2 gives a broad indication of the existing vegetative
cover within the Study Area.
Land Use
11.7.6 The Study Area is characterised by a combination of the following
land uses:
·
Natural and undeveloped areas,
particularly the upland areas including the Lam Tsuen Country Park
although these areas are crossed in a number of places by walking trails;
·
High-rise residential
development concentrated to the south (Yuen Long) and west (Tin Shui Wai) of
the development site on the valley floor;
·
Extensive areas of low-rise
development such as that of the Fairview
Park development located
to the east of the site;
·
Agricultural landscapes, both
active and abandoned located, largely at the base of the surrounding uplands
punctuated by low-rise traditional village settlements in areas such as Ng Uk
Tsuen, Sha Kong Wai
and Mong Tsuen Wai;
·
Large scale commercial and
industrial development such as the Yuen Long Industrial Estate and the Yuen
Long Sewage Treatment Works;
·
Recreational areas including
sporting facilities and recreational facilities situated in the main urban
areas of Yuen Long and Tin Shui Wai; and
·
Hong Kong Wetland Park.
11.8.1 The following sections provide a landscape impact assessment for development Options 1A and 1B. The predicted impacts on the existing
landscape resources arising from the implementation of both Options 1A and 1B are described together as they
share the same footprint and so the direct impacts for each will be the same.
Whereas the predicted impacts on the prevailing landscape character includes
some indirect impacts which might arise from the slight variations in the two
schemes and so are assessed separately.
11.8.2 Option 1A –
buildings with a maximum height of 18 storeys (8 blocks of 14-18 storeys, 7
groups of 4-8 storey low-rise buildings including a 2 storey resident’s club
house erected on 40,000m²
residential site area i.e. 32.8% Site Coverage).
11.8.3 Option 1B – buildings with a maximum height of 15 storeys (9 blocks
of 15 storeys, 7 groups of 4-10 storey low-rise buildings including a 2 storey
resident’s club house erected on 40,000m² residential site area i.e. 34.4% Site
Coverage).
Landscape Resources – Options 1A
and 1B
11.8.4 An important determinant of the landscape character within a Study
Area, which is a combination of traditional fishponds and village settlements
bounded by small agricultural fields; major urban development and remnants of
natural upland landscapes, is the type and extent of its landscape resources
both natural and cultivated. These landscape resources are shown on Figure 11.2
and the LCAs, Figure 11‑4, Figure
11‑5A and Figure
11‑5B. The following LRs have been identified within the
Study Area:
·
LR1 Existing Land Form
·
LR2 Woodland
·
LR3 Plantation
Woodland
·
LR4 Orchard
·
LR5 Shrub and Mosaic
·
LR6 Grassland
·
LR7 Agricultural Land
·
LR8 Fishponds
·
LR9 Watercourses – River and
Streams
·
LR10 Watercourses – Ditches and
Drainage Channels
·
LR11 Mangroves Forest/Mudflats
·
LR12 Wetlands
·
LR13 Existing Trees
11.8.5 For the purposes of this assessment the landscape resources are
represented by the existing land cover. The condition of these landscape
resources is also important in determining the landscape quality of the Study
Area and its sensitivity to change. Therefore the preservation and enhancement
of the existing landscape resources is important to the successful integration
of the proposals into the landscape context of the Study Area. Table 11‑5 below describes the impact on the prevailing
landscape character of the Study Area due to the loss of landscape resources
due to the development proposals.
Existing Trees – Options 1A
and 1B
11.8.6 As part of the assessment of the impact on the existing landscape
resources a broad brush tree survey was undertaken. These trees are located
throughout the Study Area although are largely concentrated in the existing
fishponds. They are formed by a combination of trees planted as part of the
settlement of this area and tree species which have naturally colonised it. The
approximate locations of the trees are presented as Figure 11‑3 Preliminary Tree Survey Plan whilst the schedule
contained in Appendix 11-1 provides details of the trees including the range of
species, size and an assessment of their condition. The survey identified
approximately 665 trees with 178 within the main development area and 487 within
the area identified for the WNR including 28 within the Alternative Egretry.
For the main part the tree species are non-native originating in Australia, India,
Indonesia and Malaysia,
and are fruit bearing being planted as part of the agricultural development of
the area. The main species within the
Study Area include Annona squamosa, Artocarpus heterophyllus, Clausena
lansium, Dimocarpus longan, Musa paradisiaca, Carica papaya, Litchi chinensis,
Melia azedarach, Psidium guajava, Macaranga tanarius and Mangifera
indica. The survey found no Old and Valuable Trees (ETWB TCW No, 29/2004
Registration of Old and Valuable Trees, and Guidelines for their Preservation),
rare or protected tree species (based on Forests and Countryside Ordinance ,
Cap. 96) or Champion Trees (identified in the book ‘ Champion Trees in Urban
Hong Kong’).
Tree Retention
11.8.7 Generally wherever possible existing trees will be retained in-situ,
and where this is not possible the trees will be considered for transplantation
and as a last resort considered for felling. Based on the findings of the
preliminary tree survey it is estimated that approximately 15 trees can be
retained on the fringes of the main development area and approximately 223
within the area forming the proposed WNR. Wherever possible the proposals for
the WNR including the removal of pond bunds have been modified to preserve
existing trees in-situ.
11.8.8 Therefore approximately 238 (36%) of the trees surveyed would be
retained under the current proposals (Figure
11‑3 Preliminary Tree Survey Plan refers).
Tree Transplantation
Proposals
11.8.9 In terms of assessing the feasibility of transplanting the existing
trees a number of factors were considered including their form, health and
amenity value. Also considered was the existence of rare and native species,
the accessibility for machinery required for transplantation; age; and the
availability and technical feasibility of providing recipient sites for the
transplanted trees.
11.8.10 Based on the preliminary tree survey and with consideration for the
factors described above it is recommended that 28 (4%) of the existing trees
are suitable for transplantation. This transplantation will be required due to
the proposed removal of pond bunds as part of the site formation for the proposed
development and the creation of the WNR. The trees identified for
transplantation include those of good form and health which are accessible to
machinery, and where possible native species such as Celtis sinensis which have ecological value.
11.8.11 These trees will be transplanted to the proposed landscape buffer to
the north of the development as shown on Figure 11-11A and 11-12A.
Tree Felling Proposals
11.8.12 The Tree Survey Report concludes that it would not be feasible to
retain or transplant approximately 399 (60%) (Figure
11‑3 Preliminary Tree Survey Plan refers) of the existing
trees for the following reasons:
·
The removal of some of the pond
bunds, where this is unavoidable, as part of the creation of the proposed WNR
and the requirement for the no net loss in fishpond area will require have an
impact on the existing trees. Wherever possible these trees, particularly the
larger groups, have been preserved through the creation of islands from the
former pond bunds.
·
In some locations the scope of
the proposed works and site formation precludes any opportunities to retain
existing trees particularly in the main development area due to the
construction of the development platform. However for a large part these trees
are fruit trees many of which are non-native (including approximately 176 Musa paradisiaca (Banana), equating to
26% of the total number of trees).
·
Where the retention of the
existing trees in-situ is not possible the trees have been considered for
transplantation however in many locations the pond bunds are too narrow and
steep sided to enable machinery access to facilitate the transplantation
operations.
·
The necessary excavation
required in order to construct the proposed basement car parking means it is
technically unfeasible to retain the trees within the development area.
·
The trees are of poor health,
condition and form.
Tree Survey Report
11.8.13 The findings and recommendations of the preliminary tree impact
assessment are subject to the completion of a detailed tree survey and felling
application in accordance with ETWB TCW No. 03/2006, Tree Preservation. This
will be conducted during the detailed design stage of the project. The methodology and scope including the
programme for the tree survey and felling application would be subject to the
approval of the relevant authorities.
Impact on Existing Landscape Resources – Options 1A and 1B
11.8.14 The main impacts on the landscape resources of the Study Area for
both options will result from the loss of the existing fishponds (LR 8) (approximately
4 ha) and pond bunds
resulting from the modification of existing landform (LR 1 Existing Landform –
approximately 4.6 ha)
for the development, and the loss of existing ditches and drainage channels (LR
10 Watercourses - approximately 800m2)
due to the proposed construction of the residential development platform and
the creation of the WNR. Despite the loss of fishpond being a small part of the
overall resource within the Study Area (approximately 2.5%) it is an important
landscape resource and so this has shaped the locatin and extent of the building
platform which has sought to minmise the impact on the integrity of the fish
pond area as far as possible. Also the location of the residential development
on the periphery of the fishpond area with its minimised landtake will reduce
potential impacts on the existing landform (LR 1) by maintaining the physical
integrity of the main area.
11.8.15 The impacts on LR 8 fish ponds will be further mitigated through the
improvement of the fish pond area leading to a net gain of 0.1ha in the area of the water body. In
addition it is considered that the proposed created marshland habitat which
forms part of landscape buffer between the development area and the WNR will
lead to a qualitative enhancement of the remaining area of this LR. Given this
the residual impacts on the fishpond area are likely to be mitigated from
moderate adverse to slight adverse when the mitigation measures are fully
implemented. Whilst the predicted impact on the landform (LR1) due to the loss
of pond bunds is likely to be slight adverse during construction phase as the
loss represents a small part of the overall resource.
11.8.16 There would be a predicted loss of 0.08 ha of existing ditches (LR 10) on the southern
side of the residential development site due to the wetland enhancement works.
These watercourses are manmade structures and make a relatively small
contribution to the existing landscape character. The proposed enhancement
works will improve the appearance of these structures and increase their
contribution to the future landscape character.
11.8.17 Impacts on the remaining landscape resources in the Study Area will
largely be negligible as the development will not cause a physical impact. This
includes the proposed creation of the woodland landscape buffer along the
periphery of the development site which will be contiguous with the existing
landscape resource (LR 3 Plantation Woodland). However with the growth to maturity of the
trees there would be a moderate beneficial residual impact on the overall
landscape resource. In addition the planting of new trees will have a moderate
beneficial residual impact on LR 13 Existing Trees due to the number of trees
to be planted and the replacement of common fruit tree species with native
species.
11.8.18 Table 11‑5 Existing Landscape Resources
and Predicted Impacts presents the predicted unmitigated and mitigated
(residual) impacts resulting from the proposed works during the construction
and operational phases of the project. These impacts also mapped on Figure 11‑9. The mitigated (residual) impacts are assessed during
the design year which for the purposes of this study is taken as being between
10 and 15 years after the schemes opening when the proposed mitigation planting
is deemed to have reached a level of maturity, which is sufficient for it to
perform the design objectives.
11.8.19 The assessment contained in Table
11‑5 and mapped on Figure
11‑9 concluded that despite the small to negligible impact
on the existing LRs (with
the exception of the loss of fish ponds which would have a moderate adverse
impact), the establishment of the WNR together with landscape buffer provided
at the boundary of the development will mitigate the loss in addition to
providing an overall enhancement of the existing fishponds, watercourses and
plantation woodland from an ecological perspective. The predicted residual
impact on these LRs is further discussed in Section 11.14.
Table 11‑5 Existing
Landscape Resources and Predicted Impacts – Options 1A and 1B
|
Landscape Resource
|
Total Area of Resource (Ha) / Loss (Ha) / % Loss
|
Sens
|
Mag of Change (Con / Oper Phase)
|
Impact on Landscape Character resulting from the loss of the
Existing Landscape Resources.
|
Significance Threshold
(Unmitigated)
|
Mitigation Measures
|
Significance Threshold
(Mitigated)
|
|
Con
|
Oper
|
Con
|
Oper
|
|
LR 1
Existing Landform
|
350 (study area) / 4 (Loss resulting from Development site including fishponds)
1%
350 (study area) / 4.6 (bunds will be modified resulting from Wetland
Nature Reserve enhancement)
1%
|
Medium
Condition, quality and maturity: High
Importance and rarity of special landscape elements: Regionally important
Ability of the LR to accommodate change: Medium
Statutory or regulatory requirements: Complies with requirements under OZP S/YL-LFS/7
|
Small / Small
Scale of the development and extent of impact compared to
the total area of LR: Small
Duration of impacts: Construction stage – Temporary
Operation Stage – Permanent
Reversibility of change: Medium within future WNR
|
The
proposals would not have a significant effect on the landform of the Study
Area despite the reclamation of existing ponds to create the development
platform. The location of the development platform along the northern base of
the Kai Shan range would form an extension to the existing dry agricultural
land which is characteristic of the landscape in the Study Area. There would
also be some loss of existing fishpond bunds (approximately 4.47ha) however this loss would not
have a significant impact on the landscape character of the area.
|
Moderate
Adverse
|
Moderate
Adverse
|
OP1,OP2 and OP5
|
Slight Adverse
|
Slight Adverse
|
|
LR 2
Woodland
|
19.61 / 0.0
0%
|
High
Condition, quality and maturity: High
Importance and rarity of special landscape elements : Locally important
Ability of the LR to accommodate change: Low
Statutory or regulatory requirements: Complies with requirement under OZP S/YL-LFS/7
|
Nil/ Nil
Scale of the development and extent of impact compared to
the total area of LR: Negligible
Duration of impacts: Construction stage – Nil
Operation Stage – Nil
Reversibility of change: Medium
|
These resource including
areas of Fung Shui woodlands are largely located on the lower hill slopes of
the Kai Shan range forming a
green back drop to views of the development site from the
north. However the proposals being situated on the valley floor would not
impact upon the existing woodland resource.
|
Negligible
|
Negligible
|
As there are no direct impacts to the LR no mitigation is required
although it is considered that the overall landscape and visual mitigation
approach will enhance the overall landscape character and quality of the
local area. This includes OP1, OP2 and OP3 which will contribute to the
woodland resource within the study area.
|
Negligible
|
Negligible
|
|
LR 3
Plantation Woodland
|
3.03 / 0.0
<1%
|
High
Condition, quality and maturity: High
Importance and rarity of special landscape elements : Locally important
Ability of the LR to accommodate change: Low
Statutory or regulatory requirements: Compiled with requirement under OZP S/YL-LFS/7
|
Small
Scale of the development and extent of impact compared to
the total area of LR: Small
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Medium
|
This resource is largely
situated in the centre of Hong Kong Wetland Park
to the north west
of the Study Area and would be untouched by the development proposals. New buffer planting proposed at
the southern edge of the development in conjunction with the plantation
woodland located at northern edge of Ng Uk Tsuen will enhance the local
landscape context and benefit to this landscape resource.
|
Negligible
|
Moderate
Beneficial
(due to provision of landscape buffer planting at
the boundary of the development providing a net gain of this LR as discussed
in Table 12 of this report)
|
CP1, CP3, OP2 and OP3
|
Negligible
|
Moderate
Beneficial
(due to fully establishment of the planting proposal for the development
provide a net gain of this LR as discussed in Table 12 of this report)
(Net gain of 3,750m2
woodland buffer within the development site.)
|
|
LR 4
Orchard
|
1.44 / 0.0
0%
|
Medium
Condition, quality and maturity: Medium
Importance and rarity of special landscape elements: Locally important
Ability of the LR to accommodate change: Medium
Statutory or regulatory requirements: Nil
|
Nil/ Nil
Scale of the development and extent of impact compared to
the total area of LR: Negligible
Duration of impacts: Construction stage – Nil
Operation Stage – Nil
Reversibility of change: Medium
|
There are three main
areas of orchard located to the south of the Study Area adjacent to the
existing village developments north of Ng Uk Tsuen. The orchards are also
planted contiguous to woodland areas. There would be no impact on this
resource.
|
Negligible
|
Negligible
|
As there are no direct impacts to the LR no mitigation is required
although it is considered that the overall landscape and visual mitigation
approach will enhance the overall landscape character and quality of the
local area. This includes OP1, OP2 and OP3 which will contribute to the
woodland resource within the study area.
|
Negligible
|
Negligible
|
|
LR 5
Shrub Mosaic
|
20.46 / 0.0
0%
|
Medium
Condition, quality and maturity: Low
Importance and rarity of special landscape elements : Low
Ability of the LR to accommodate change: Medium
Statutory or regulatory requirements: Nil
|
Nil/ Nil
Scale of the development and extent of impact compared to
the total area of LR: Negligible
Duration of impacts: Construction stage – Nil
Operation Stage – Nil
Reversibility of change: Medium
|
The main areas of this
resource are situated on the upper hill slopes and summits of the peaks
forming the Kai Shan range and would not be affected by the development
proposals.
|
Negligible
|
Negligible
|
As there are no direct impacts to the LR no mitigation is required
although it is considered that the overall landscape and visual mitigation
approach will enhance the overall landscape character and quality of the
local area.
|
Negligible
|
Negligible
|
|
LR 6
Grassland
|
4.19 / 0.0
0%
|
Low
Condition, quality and maturity: Low
Importance and rarity of special landscape elements : Low importance
Ability of the LR to accommodate change: High
Statutory or regulatory requirements: Nil
|
Nil / Nil
Scale of the development and extent of impact compared to
the total area of LR: Negligible
Duration of impacts: Construction stage – Nil
Operation Stage – Nil
Reversibility of change: High
|
Small pockets of
grassland are located throughout the Study Area although primarily located
adjacent to the Closed Area Boundary road to the north of the existing
fishpond areas. The existing grassland will not be affected by the development
proposals.
|
Negligible
|
Negligible
|
As there are no direct impacts to the LR no mitigation is required
although it is considered that the overall landscape and visual mitigation
approach will enhance the overall landscape character and quality of the local
area.
|
Negligible
|
Negligible
|
|
LR 7
Agricultural Land
|
7.04 / 0.0
0%
|
Medium
Condition, quality and maturity: Low
Importance and rarity of special landscape elements : Low importance
Ability of the LR to accommodate change: High
Statutory or regulatory requirements: Nil
|
Nil / Nil
Scale of the development and extent of impact compared to
the total area of LR: Negligible
Duration of impacts: Construction stage – Nil
Operation Stage – Nil
Reversibility of change: High
|
The main areas of
agricultural land are located to the south of the Study Area at the base of
the Kai Shan hill range. This transition from fishpond to dry agricultural
land to the wooded hillsides of the uplands is characteristic of the Study
Area and the north west New Territories
in general. The resource includes both active and inactive (5.17ha) agricultural land. The
development proposals would not affect the extent of this resource within the Study Area.
|
Negligible
|
Negligible
|
As there are no direct impacts to the LR no mitigation is required
although it is considered that the overall landscape and visual mitigation
approach will enhance the overall landscape character and quality of the
local area.
|
Negligible
|
Negligible
|
|
LR 8
Fishponds
|
Loss
resulting from the residential
development
170.29
/ 4.07 / 2.4%
Area enhanced by
the Wetland Nature Reserve
170.29
/ 75.95 /
45%
No
net loss of water body
|
High
Condition, quality and maturity: High
Importance and rarity of special landscape elements: Regionally important
Ability of the LR to accommodate change: Low
Statutory or regulatory requirements: Compiled with requirement under OZP S/YL-LFS/7
|
Small
/ Small
Scale of the development and extent of impact compared to
the total area of LR: Small to Intermediate
Duration of impacts: Construction stage – Temporary
Operation Stage – Permanent
Reversibility of change: Low for area affected by the building footprint
|
The loss of
approximately 2.4% out of a total area of approximately 170ha of fishponds is not considered
significant in terms of the percentage of loss however in terms of the
physical size of the area (4ha)
this is an extensive area. This is an important regional landscape resource
and so any loss is important. For this reason the location of the area
affected by the proposals has been restricted to an area contiguous with
existing hillsides and so would not affect the physical integrity of the
remnant portion thus minimising the impact of this loss of LR on the
landscape character of the area. The enhancement works proposed for
the WNR will benefit the landscape context in long term following the
completion of the works.
|
Moderate
Adverse
(due to modification of existing fish pond bunds)
|
Moderate
Adverse
(due to modification of existing fish pond bunds)
|
Primary mitigation through the location of the residential
development on the southern periphery of the fishpond area minimising the
disturbance to the remaining fishponds. Enhancement of the marshland
(OP2).
|
Moderate
Adverse
|
Moderate
Adverse
(due to proposed fish pond enhancement and
introduction of active amendment ) (slight net gain
in the area of the water body within proposed WNR)
|
|
LR 9
Watercourses
- Rivers and Streams
|
25.24 / 0.0
0%
|
High
Condition, quality and maturity: High
Importance and rarity of special landscape elements : Locally important
Ability of the LR to accommodate change: Low
Statutory or regulatory requirements: Nil
|
Nil/ Nil
Scale of the development and extent of impact compared to
the total area of LR: negligible
Duration of impacts: Construction stage – Nil
Operation Stage – Nil
Reversibility of change: High
|
Many of the
larger existing watercourses within the Study Area which influence its
perceived landscape character have been modified these include the retrained
river channels to the west of Tin Shui Wai, and the Shan Pui and Shan Chun
Rivers. Therefore these features have a low sensitivity to further change
however there would be direct or indirect impacts on these resources.
|
Negligible
|
Negligible
|
As there are no direct impacts to the LR no mitigation is required
although it is considered that the overall landscape and visual mitigation
approach will enhance the overall landscape character and quality of the
local area.
|
Negligible
|
Negligible
|
|
LR 10
Watercourses
- Ditches and Drainage Channels
|
0.47 / 0.08 /
17%
|
Low
Condition, quality and maturity: Low
Importance and rarity of special landscape elements : Low importance
Ability of the LR to accommodate change: High
Statutory or regulatory requirements: Nil
|
Small / Small
Scale of the development and extent of impact compared to
the total area of LR: Small
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Low for area
affected by the building footprint and high for other areas
|
Four drainage ditches
were identified within the Study Area used for moving water between the
fishponds. These have a low value in terms of their contribution to the
existing landscape character. Only 4% of this resource will be affected by
the residential development, the other 13% affected area will be enhanced
through the Wetland Nature Reserve proposals.
|
Slight Adverse
|
Slight Adverse
|
OP2, OP4
|
Slight Adverse
|
Slight Adverse
|
|
LR11
Mangrove Forest / Mudflats
|
48.44 / 0.0
0%
|
High
Condition, quality and maturity: High
Importance and rarity of special landscape elements : Regionally important
Ability of the LR to accommodate change: Low
Statutory or regulatory requirements: Complies with requirement under OZP S/YL-LFS/7
|
Nil / Nil
Scale of the development and extent of impact compared to
the total area of LR: Negligible
Duration of impacts: Construction stage – Nil
Operation Stage – Nil
Reversibility of change: High
as LR not physically affected
|
Located in the northern
part of the Study Area this resource includes naturally regenerating mangrove
forest interspersed by mudflats forming the estuarine landscape of the Shan
Pui, Sham Chun and Tai
Rivers. There would be no direct or indirect
impacts to this landscape resource.
|
Negligible
|
Negligible
|
As there are no direct impacts to the LR no mitigation is required
although it is considered that the overall landscape and visual mitigation
approach will enhance the overall landscape character and quality of the
local area.
|
Negligible
|
Negligible
|
|
LR 12
Wetlands
including reed beds and permanent
freshwater marsh and pools
|
3.14 / 0.0
<1%
|
High
Condition, quality and maturity: High
Importance and rarity of special landscape elements: Regionally important
Ability of the LR to accommodate change: Low
Statutory or regulatory requirements: Complies with requirement under OZP S/YL-LFS/7
|
Nil / Small
Scale of the development and extent of impact compared to
the total area of LR: Small to Negligible
Duration of impacts: Construction stage – Nil
Operation Stage – Nil
Reversibility of change: High
|
The wetlands including
reed beds are restricted to a small area, probably an abandoned fishpond in
the southern part of the Study Area characterised by Phragmites.
Whilst areas of marsh occur in the southern part of the Study Area closely
associated with various agricultural land-uses. It is likely that these areas
of marsh have formed on land previously used for aquaculture or wet
agriculture. The wetlands found within the Study Area do not represent a
significant landscape resource in terms of its shaping landscape character.
|
Negligible
|
Negligible
|
OP2, OP4
|
Negligible
|
Negligible
|
|
LR 13
Existing Trees
|
665 trees in total with 178 trees within the main development area
and 487 trees within the area
identified for the WNR / 301 trees / 45%
|
High to medium
Condition, quality and maturity: Generally medium to low (although some good specimen trees)
Importance and rarity of special landscape elements: Locally important
Ability of the LR to accommodate change: Medium
Statutory or regulatory requirements: Requiores formal felling application in accordance with
WBTC No. 03/2006
|
Intermediate / Small
Scale of the development and extent of impact compared to
the total area of LR: Intermediate
Duration of impacts: Construction stage – Termporary
Operation Stage – Nil
Reversibility of change: High
|
The
existing trees are largely located within LR8 Fishponds and are formed by a
combination of trees planted as part of the settlement of this area and tree
species which have naturally colonised it. The approximate locations of the
trees are presented as Figure 11-3 Preliminary Tree Survey Plan whilst the
schedule contained in Appendix 11-1 provides details of the trees including
the range of species, size and an assessment of their condition. For the main
part the tree species are non-native originating in Australia, India,
Indonesia and Malaysia,
and are fruit bearing being planted as part of the agricultural development
of the area. This includes a large proportion of fruit trees including
approximately 176 Musa paradisiaca
(Banana), equating to 27% of the total number of trees). No rare or protected
species were identified as part of the preliminary tree survey.
|
Moderate
|
Moderate
beneficial
|
OP2, OP3 and OP4
|
Moderate
|
Moderate beneficial
|
Key
Landscape Sensitivity
(Sens): Low, Medium or High
Condition, quality and
maturity; importance and rarity of special landscape elements; and ability of
the LR to accommodate change: Nil, Low, Medium or High
Magnitude of Change
(Mag): Negligible, Small, Intermediate
and Large
Scale of the
development and extent of impact compared to the total area of LR; duration of
impacts; and reversibility of change: Nil, Low, Medium or High
Significance Threshold: Negligible,
Slight, Moderate and Significant (adverse or beneficial)
Residual Impacts: Refer
to matrix and table in methodology section
Con: Construction
phase impacts
Oper: Operational
phase impacts
Landscape Character
11.8.20 The landscape character of the Study Area, located adjacent to Deep Bay in
the northwest New
Territories, is strongly
influenced by the traditional fishponds which characterise the low lying
coastal plain. The area is bisected by the Tin Shui Wai Drainage Channel and Shan Pui
River. The landscape
character of this area is formed by a largely undeveloped flat expanse of the
fishponds bounded by the upright form of the surrounding hill sides. The
relationship between the fishponds, the mud flats and the wooded hills sides is
important to the landscape character of the area. Figure 11‑4 shows the location of the LCAs which form the Study
Area, and Figure 11‑5A and B demonstrate how these various characters fit
together.
11.8.21 Table 11‑6 presents a description of the following LCAs which make up the Study
Area, the predicted impacts and recommended mitigation measures.
·
NUA 1 Natural Upland Landscape
Character Area - Kai
Shan Range
·
V1 Village Landscape Character Area - Ng Uk
Tsuen Village Cluster
·
AGR1 Agriculture Landscape Character Area – Fung Kai Wai – Ng Tung Uk
Agricultural Fields
·
AGR2 Agriculture Landscape
Character Area – Fishponds
·
ICA1 Industrial/Commercial
Landscape Character Area – Yuen Long Industrial Estate
·
OS1 Open Space and Parks Landscape Character Area – Hong Kong Wetland
Park
·
EL1 Estuarine Landscape Character Area – Kam Tin and Shan Pui River Estuaries, and the Tin Shui Wai Drainage Channel
Impacts on Landscape Character - Options 1A and 1B
11.8.22 The potential impacts arising from options 1A and 1B on the existing landscape charcter would be
largely similar due to
their shared development footprint and hence the same direct impact on the
landscape character of the area. This is mirrored in the potential indirect
impacts as the differences in the design of the two schemes would not result in
an appreciable difference in the potential impacts.
11.8.23 The Kai
Shan Range
(NUA 1) and the settlements of the Ng Uk Tsuen Village Cluster (V1) situated in
the saddle between the primary and secondary peaks would not experience any
direct impacts as a result of the development proposals. However there will be
some indirect moderate adverse impacts during the construction phase due to the
proximity of the proposed development and the alignment of the proposed
development access. These impacts would be alleviated to an extent through the
proposed mitigation with a slight adverse impact during the operational phase.
11.8.24 The landscape character of the Fishponds (AGR 2) would be subject to
direct impacts. The loss of the existing fishponds, albeit a small area on the
southern periphery, would lead to a moderate to significant adverse impact
during construction and operational phases in the absence of landscape
mitigation measures. This is largely due to the openness of the landscape
within this area, its intervisibility and the interruption of the transition
from fishpond to agricultural fields and eventually wooded hill slope. This
impact on this LCA will be alleviated to moderate adverse through the utilisation
of the proposed responsive building design with view corridors, a stepped
building height profile which seeks to alleviate the abrupt transition with the
flat landscape to the north and the proposed marshland and woodland buffer area
which enhance the integration of the proposals.
11.8.25 There would be no direct impact to the Hong Kong Wetland
Park (OS 1) landscape
character area during the construction phase of the project. It is remote to
the development site and so there would be no physical loss of landscape
features within this area. However with the establishment of the proposed marsh
habitat and the fishpond enhancement forming part of the development, the
southern periphery of the park will be enhanced and so result in a beneficial
impact following full establishment. This is largely due to the beneficial
effect of extending the buffer between the built environment and the
traditional fishpond landscape.
11.8.26 The impact on the existing agricultural fields to the south west of
the Study Area (AGR 1) would be negligible due largely to the screening effect
of the vegetation at the periphery of the village settlements. This is also
true of the Yuen Long Industrial Estate (ICA
1) which will be screened from the proposed development by the landform of the
Kai Shan range and the woodland associated with the lower hill slopes. There
would be a negligible impact on the landscape character of the Kam Tin and Shan
Pui River Estuaries, and the Tin Shui Wai Drainage Channel (EL1) due to their
distance from the proposed development site.
11.8.27 Table 11‑6 presents the unmitigated and mitigated (residual)
impacts arising from the scheme proposals during the construction and
operational phases of the project. The mitigated (residual) impacts are
assessed during the design year which for the purposes of this study is taken
as being between 10 and 15 years after the schemes opening when the proposed
mitigation planting is deemed to have reached a level of maturity sufficient
for it to perform the design objectives.
Table 11‑6 Existing Landscape Character and Predicted Impacts – Options 1A and 1B
|
Landscape Character Area (LCA)
|
Sens
|
Mag of Change
(Con / Oper Phase)
|
Main Impacts on Landscape Character Area
|
Impact Significance Threshold
(Unmitigated)
|
Mitigation Measures
|
Impact Significance Threshold
(Mitigated)
|
|
Con
|
Oper
|
Con
|
Oper
|
|
Natural
Upland Landscape Character Area (NUA)
|
|
|
|
|
|
|
|
|
|
NUA
1: Kai Shan Range.
The
Kai Shan Range
forms the dominant landform within the Study Area being characterised by a
range of minor peaks creating a ridgeline on a northeast – southwest axis.
The primary peak (Kai Shan) rises to 121mPD with the main secondary peak to
the north of Ng Uk Tsuen rising to 62mPD. The existing service reservoir to
the north of Kai Shan forms is visually apparent in views from the fishponds
to the south.
The hillsides are clothed in dense woodland which gives way to shrubland and
grassland towards the summits. This
feature in conjunction with the fishponds to Kai Shan
is important in establishing the overall landscape character of the Study
Area.
|
High
Condition, quality and maturity: High
Importance and rarity of special landscape features: Locally important
Ability of the LCA to accommodate change: Medium
Statutory or regulatory requirements: Complies
with requirements under OZP S/YL-LFS/7
|
Intermediate / Small
Scale of the development relative to baseline conditions: Intermediate
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change:
Medium
|
There
will be no direct impacts on the Kai Shan range however indirect impacts will
include the impact on the landscape setting of the range particularly in the
transition from the low-lying agricultural plain.
|
Moderate
Adverse
|
Moderate Adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation CP1, CP4, OP1, OP2, and OP4.
|
Moderate
Adverse
|
Slight Adverse
|
|
Village Landscape Character Area (V)
|
|
|
|
|
|
|
|
|
|
V1:
Ng Uk Tsuen Village
Cluster
The
traditional villages of Ng Uk Tsuen, Shing Uk Tsuen and Tai Tseng Wai are
located in the saddle between the two main peaks described above. The
villages are characterised by largely typical village
houses three storeys in height with tiled facades and flat roofs with shade
structures. The three villages have coalesced into a single settlement
although only the properties on the northern periphery of Shing Uk Tsuen have
a view over the development area. The remaining houses are largely screened
by the adjacent development, and the existing landform and mature vegetation
to the south of the development site.
|
Medium
Condition, quality and maturity: Medium
Importance and rarity of special landscape elements : Low
Ability of the LCA to accommodate change: High
Statutory or regulatory requirements: Complies
with requirement under OZP S/YL-LFS/7
|
Intermediate
Scale of the development relative to baseline conditions: Intermediate
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility
of change: Medium
|
There
will be no direct impacts on the village cluster however indirect impacts
will include the impact on the landscape setting of the northern village
houses of Shing Uk Tsuen. The other villages areas are screened by the
existing landform and the woodland situated in the saddle between the two
main peaks of the Kai Shan range. The proposed construction and operation of
the Southern Development Access will be within existing land take and so no
long term impacts are envisaged.
|
Moderate
Adverse
|
Moderate Adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation CP1, CP3, CP4, OP1, OP2, and OP4.
|
Moderate
Adverse
|
Slight
Adverse
(due
to full establishment of landscape buffer at the southern boundary of the
development which enhances the local
landscape character)
|
|
Agriculture Landscape Character Area (AGR)
|
|
|
|
|
|
|
|
|
|
AGR1:
Fung Kai Wai – Ng Tung Uk Agricultural Fields
This
LCA to the south west of the Study Area is primarily characterised by a
combination of active and inactive agricultural land. The characteristics of
the landscape are the fine texture of agricultural fields punctuated by
low-rise village type development and large individual specimen trees and
small tree groups. The development site is located to the northern edge of
this character area and is enclosed on the southern side by the wooded
hillsides of the Kai Shan range.
|
Medium
Condition, quality and maturity: Medium
Importance and rarity of special landscape elements : Low
Ability of the LCA to accommodate change: High
Statutory
or regulatory requirements: Complies
with requirement under OZP S/YL-LFS/7
|
Negligible / Negligible
Scale of the development relative to baseline conditions: Negligible
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Nil
Operation Stage – Nil
Reversibility of change:
Medium
|
There
will be no direct or indirect impact on the character of this area as it is
situated to the south of the residential development site and screened by
existing trees and village development.
|
Negligible
|
Negligible
|
No mitigation required.
|
Negligible
|
Negligible
|
|
AGR2:
Fishponds
This
LCA forms the landscape character for the Study Area north of the proposed
development. The ponds are generally rectangular in shape separated by earth
bunds which are clothed in grass with the occasional clumps of trees and
shrubs or specimen mature trees. The ponds are generally active although
several areas are used for agriculture. Within this area are several isolated
single storey
structures located on the bunds between the ponds
and are often accompanied by groups of mature trees. The ponds provide an
important component of the overall landscape character of the Study Area. The
low level of existing disturbance and its open, expansive nature result in a
high landscape quality and sensitivity to further change.
|
High
Condition, quality and maturity: High
Importance and rarity of special landscape elements : Regionally important.
Ability of the LCA to accommodate change: Low
Statutory
or regulatory requirements: Complies
with requirement under OZP S/YL-LFS/7
|
Small to Intermediate / Small to Intermediate
Scale of the development relative to baseline conditions: Small to intermediate
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operation Stage – Permanent
Reversibility of change:
Medium
|
The
proposed development will be located on a platform constructed from reclaimed
fishponds and so there will be a direct impact on the character of this area.
However, the development area is located on the southern periphery of the
fishponds therefore minimising any loss of physical integrity. A precedent
has been established for development in close proximity with the fishpond
area due to the development associated with Tin Shui Wai.
|
Significant Adverse
|
Significant
Adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation CP1, CP3, CP4, OP1, OP2, and OP4.
|
Significant Adverse
|
Moderate
Adverse
(Due to fishpond improvement and the creation of
marsh habitat)
|
|
Industrial / Commercial Landscape Character Area (ICA)
|
|
|
|
|
|
|
|
|
|
ICA1:
Yuen Long Industrial Estate
This
LCA to the south of the Study Area is characterised by the industrial and
utilitarian nature of its land uses. The industrial estate extends from the
southern periphery of Tai Tseng Wai south to the Shan Pui River. These main structures within
the estate include a number of large factory and warehouse complexes set
within a grid like street pattern.
There is little in terms of soft landscape within the estate with the
exception of intermittent street tree planting along Wang Lee, Wang Lok and Fuk Hi Streets.
This disparate mix of industrial land uses provides an incoherent landscape
which is further degraded by vehicle yards and parking at ground level. The
combined development serves to degrade the character of the southern part of
the Study Area although this development is screened from the proposed
development area.
|
Low
Condition, quality and maturity: Low
Importance and rarity of special landscape elements : Low importance
Ability of the LCA to accommodate change: High
Statutory
or regulatory requirements: Nil
|
Negligible / Negligible
Scale of the development relative to baseline conditions: Negligible
Compatibility of the project with the surrounding
landscape: High
Duration of impacts: Construction stage – Nil
Operation Stage – Nil
Reversibility
of change: High
|
There
will be no direct or indirect impact on the character of this area as it is
removed from the development site.
|
Negligible
|
Negligible
|
No mitigation required.
|
Negligible
|
Negligible
|
|
Open Space and Park Landscape Character Area (OS)
|
|
|
|
|
|
|
|
|
|
OS1:
Hong Kong Wetland Park
The
Hong Kong Wetland Park (HKWP) is located to the west of the Study Area forms
a transitional zone or buffer between the high-rise residential development
associated with Tin Shui Wai and the horizontal low-lying form of the
fishponds to the east. The Hong Kong Wetland Park
will be characterised by a combination of woodland structure planting,
wetland areas and open water.
|
High
Condition, quality and maturity: High
Importance and rarity of special landscape elements : regional important
Ability of the LCA to accommodate change: Low
Statutory or regulatory requirements: Hong
Kong Country Park Ordinance
|
Negligible / Small
Scale of the development relative to baseline conditions: small
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operation Stage – Permanent
Reversibility of change:
Medium
|
There
will be no direct impact on the character of this area as it is remote from
the residential development site.
However the proposed marsh habitat to the north of the development
site will be contiguous with the HKWP and so form a continuous band of
marshland along the western periphery of the fishponds.
|
Negligible
(Remote
from the site)
|
Negligible
(Remote
from the site)
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation CP1, CP3, CP4, OP1, OP2, and OP4.
|
Negligible
(Remote
from the site)
|
Slight
Beneficial
(WNR proposals enhance southern edge of HKWP)
|
|
Estuarine Landscape Character Area (EL)
|
|
|
|
|
|
|
|
|
|
EL1: Kam Tin and Shan Pui River Estuaries, and the Tin Shui Wai
Drainage Channel
The
estuarine landscapes to the north and of the Study Area are characterised by
extensive mangroves giving way to areas of mudflats in the inter-tidal areas.
Although the dominant vegetation is mangroves. The area is contained by the
high security fence of the Closed Area Boundary which is visible from the
fishpond areas to the south. The mangroves form an important vegetative
component of the estuarine landscapes particularly in elevated views of the
Study Area.
|
Low
Condition, quality and maturity: Low
Importance and rarity of special landscape elements: Low
Ability of the LCA to accommodate change: High
Statutory
or regulatory requirements: Nil
|
Negligible/ Negligible
Scale of the development relative to baseline conditions: Negligible
Compatibility of the project with the surrounding
landscape: High
Duration of impacts: Construction stage – Nil
Operation Stage – Nil
Reversibility of change:
Medium
|
There
will be no direct or indirect impact on the character of this area as it is
remoted from the development site.
|
Negligible
|
Negligible
|
No mitigation required.
|
Negligible
|
Negligible
|
Key
Landscape Sensitivity
(Sens): Low, Medium or High
Condition, quality and
maturity; importance and rarity of special landscape elements; and ability of
the LCA to accommodate change: Nil, Low, Medium or High
Magnitude of Change
(Mag): Negligible, Small, Intermediate
and Large
Scale of the
development relative to baseline conditions; compatibility of the project with
the surrounding landscape; duration of impacts; and reversibility of change:
Nil, Low, Medium or High
Significance Threshold: Negligible,
Slight, Moderate and Significant (adverse or beneficial)
Residual Impacts: Refer
to matrix and table in methodology section
Con: Construction
phase impacts
Oper: Operational
phase impacts
11.9
Existing Visual Context and
Visual Impacts
Existing Visual Context
Visual Envelope and
Zones of Visual Influence
11.9.1 The Visual Envelope (VE) for proposed development Options 1A and 1B extends north, east and
northwest across the coastal plain and estuarine landscape to the surrounding
natural uplands. It is not considered that the visual envelopes for the two
options would be significantly different although the visual prominence of
Option 1B would be reduced from within the central and southern parts of the
villages to the south of the proposed development site. The development site is
bounded by the Kai Shan range to the south which serves to largely contain
views. Whilst to the west the VE is contained by the existing high-rise
development associated with Tin Shui Wai.
In terms of the available viewing distances typically views extend some 2.0km north, 2.5km east, 0.50km
south and 1.0km
west. Within this VE the extent of the existing views is determined by factors
such as the presence of intervening visual obstacles and so a number of Zones
of Visual Influence (ZVI) can be discerned. The VE and ZVIs are mapped on
Figure 11-6 and the
photographs presented as Figure 11-7 demonstrates the components which make up the
existing visual amenity.
Existing Visually
Detracting Elements
11.9.2 A number of the existing elements within the landscape of the Study
Area may be considered as visually detracting in that they are visually
incompatible with the existing landscape and visual context. The position of
these elements and their role within the visible landscape is shown on
including:
·
The industrial, commercial and
utility development located to the north of Yuen Long including the Yuen Long
Sewage Treatment Works (STW). This complex particularly the STW is prominent in
views from the north and east.
·
The high-rise development
associated with Tin Shui Wai which is characterised by its uniform building
height, the consistent appearance of the building facades; and the developments
prominence in views from the fishpond area to the north of the development site
and in views from the residential areas to the east of the Study Area.
·
The drainage channel works for
the Kam Tin and Shan Pui River Estuaries, and the Tin Shui Wai Drainage Channel
which have replaced the natural meandering form of the original river courses
with a more engineered form. These features are prominent in elevated views of
the Study Area and in views from the east.
Existing Visual Amenity
and Visually Sensitive Receivers
11.9.3 In broad terms for both Options 1A
and 1B there are three zones of visual influence (ZVIs), named ZVI 1, ZVI 2 and
ZVI3, within the visual envelope (VE) of the development having distinct visual
amenity characters in the landscape context, these ZVIs are shown on Figure 11‑6. VSRs identified within the ZVIs are grouped by development as many
of the residents of these developments and visitors looking from surrounding
hillside footpath or lookout point in the VE who will be subject to similar
views. The existing view, predicted impacts and recommended mitigation measures
for each of the identified VSRs are presented in Table 11‑7 and Figure
11‑10.
11.9.4 The visual amenity observed by VSRs inside ZVI 1 is characterised by
the views over the existing fishponds. This is an area of expansive low-level
views extending to the wooded hillsides and views into Deep Bay.
The views along the valley floor are generally interrupted beyond the area of
fishponds due to the existing vegetation particularly trees on the pond bunds.
Other components of these views include the vertical forms of the high-rise
development, which visually encloses the Study Area. Views within this area are
generally of high to medium quality. The sensitivity of these views to further
change is generally high due to the unique nature of the landscape and the
relative absence of built development in views to the north and east.
11.9.5 The visual amenity observed by VSRs inside ZVI 2 is that of the
natural uplands which form the main landscape and visual context for the Study
Area. These upland areas form a
green back cloth to many of views from within the Study Area
particularly those from low level within the coastal plain and estuarine
landscape. These upland areas generally form the limit to the visual envelope
and so form the visual horizon. However these views to the west and south of
the Study Area are interrupted due to the intervening high-rise development and
the ridgeline is breached by some of the existing development particularly that
of Tin Shui Wai. This would indicate that views which are already characterised
by high-rise development are not sensitive to further change.
11.9.6 The visual amenity observed by VSRs inside ZVI 3 is formed by the
dense high-rise development which generally serve to enclose and foreshorten
internal views although offering generally spectacular views for VSRs on the
periphery of the developments particularly those adjacent to the fishponds. The
internal views within the development areas are generally of poor quality and
have a low sensitivity to further change due to the existing level of
development. Views from the properties on the periphery of these development
areas are generally of high quality, as has been described above, having views
over the fishponds and the estuarine landscape of Deep Bay. These views have a
medium to high sensitivity to further change depending on their location and
the nature of the VSRs.
11.9.7 The next section assesses the potential visual impacts arising from development Options 1A and 1B.
11.9.8 Option 1A –
buildings with a maximum height of 18 storeys (8 blocks of 14-18 storeys, 7
groups of low-rise buildings of 4-8 storey including a 2 storey resident’s club
house erected on 40,000m²
residential site area i.e. 32.8% Site Coverage).
11.9.9 Option 1B – buildings with a maximum height of 15 storeys (9 blocks
of 15 storeys, 7 groups of 4-10 storey low-rise buildings including a 2 storey
resident’s club house erected on 40,000m² residential site area i.e. 34.4% Site
Coverage).
Visual Impacts: Option 1A
Views from Residences
11.9.10 Residents of the new development on the north western periphery of
Tin Shui Wai (VSR 1) such as residents of Tin Heng Estate and the southern
periphery of Mong Tseng Wai (VSR 3) will be subject to a moderate adverse
impact in the absence of mitigation measures. This is largely due to the
expansive nature of the existing views and the viewing distances involved
(approximately 2000-2300m).
The residents of Tin Shui Wai (VSR 1) would experience a similar level of
impact although for some of the lower storeys the view would be blocked or
interrupted after the completion of CDA development at Area 112 in the foreground of available
views.
11.9.11 Residents on the eastern periphery of Fairview Park
(VSR 4) will be subject to a slight to moderate adverse impact and Tai Sang Wai
(VSR 5) a slight adverse impact in the absence of mitigation measures. The
level of predicted impact is determined by the viewing angle and distances
involved (2300-2400m)
and the availability of other views within an expansive panorama. In addition
the visible part of the development will be along the shortest development
facade and will be seen against the existing high-rise development of Tin Shui
Wai.
11.9.12 The residents of Ng Uk Tsuen (VSR 6) and Shing Uk Tsuen (VSR 7)
(approximately 10 houses in each case) living at the northern periphery of the
villages with windows facing north to the development site will experience significant to moderate adverse impacts in the
absence of mitigation measures due to their proximity to the proposed
development. However views from many of these villages houses are partially
obstructed by the existing landform, vegetation and structures. For other
residents of the villages, pedestrians within open spaces and vehicle
travellers on the roads through the villages the impacts are likely to be
slight to moderate adverse due to the screening effect of adjacent village houses,
the angle and viewing distance, and the proximity of existing vegetation. For
these VSRs the views will be glimpsed and limited to the upper floors of the
proposed development.
11.9.13 Residents of Long Ping Estate (VSR 9) to the north of Yuen Long and
Tin Tsz Estate (VSR 10) who have views across the development site will be
subject to a slight to
moderate adverse impact in the absence of landscape mitigation measures. This
is due to the proposed development will be largely screened in these views by
the Kai Shan range and the impacts mitigated to an extent by the existing
development in the foreground of the views.
11.9.14 The residents of the Kenwood
Court (VSR 11) on the eastern edge of Tin Shui Wai
would be subject to a moderate adverse impact in the absence of mitigation
measures due to the proximity of the development although the residents would
have alternative views across the fishponds towards Deep Bay.
The visible part of the proposed development would again be the narrowest
building facade.
11.9.15 The residents of the eastern peripheral of Tin Yuet Estate (VSR 12)
on the western edge of Tin Shui Wai would be subject to a moderate adverse
impact in the absence of mitigation measures due to the viewing distance. In
addition there is likely to be a cumulative impact for these VSRs through the
proposed CDA development in Areas 103 and 104.
11.9.16 The residents of the east facing apartments of the Vianni Cove (VSR
14) and the Grandeur Terrace (VSR 15) on the eastern periphery of Tin Shui Wai
will be subject to a moderate adverse impact. The impact of the proposed
development on views for those residents will be mitigated to an extent by the
relatively small proportion of the view affected and the viewing distances
involved. There is also likely to be a cumultaive impact for these residents with the future CDA
development in Areas 112 and 115.
11.9.17 Future residents on the eastern periphery of the proposed CDA in
Area 115 located adjacent to Wetland
Park Road (PVSR A1) will be subject to moderate adverse impacts in the absence of
mitigation measures. The level of the predicted impact will be determined by a
combination of the low level of this PVSR and the screening effect of the
existing vegetation to the south east of the development area, the screening
effect of the proposed development inside the settlement and the viewing
distances involved.
View from Workplaces
11.9.18 Site observation would suggest that most of fishponds and
agricultural lands within the Study Area are inactive and so have not been
identified as VSRs in category.
Views from Recreational
Landscapes
11.9.19 Visitors to the area and locals visiting the lookout point at Tsim
Bei Tsui (VSR 2) will be subject to a moderate adverse impact arising from the
implementation of the development proposals. The level of the predicted impact
is largely determined a combination of the transient nature of potential
viewers, the viewing distances involved, the relatively small scale of the
proposed development and the panoramic nature of the existing view. Walkers
using the footpath trails on Kai Shan (VSR 8) will be subject to a moderate
adverse impact due to the proximity of the development, the elevated viewing
position and the disruption of views across the existing fishponds to Deep Bay.
11.9.20 Views available to the visitors and staff of the Hong Kong Wetland
Park (VSR 13) would be
mitigated to an extent by the low-lying nature of the VSR and the screening
effect of the intervening vegetation both within the park and along its
southern boundary. However due to the relative sensitivity of the existing view
and the nature of the VSR the visual impact is likely to be moderate adverse. Again views would be limited to the very upper floors
of the proposed development which would be visually permeable to an extent due
to the building orientation of the four westernmost residential blocks.
Views for travellers on Public Roads and Railways
11.9.21 The potential visual impacts for vehicle travellers on the roads
which run through Ng Uk Tsuen (VSR 6) and Shing Uk Tsuen (VSR 7) are likely to
be slight to moderate adverse due to their transient nature, the screening
effect of adjacent village houses and vegetation, and the angle and viewing
distance. For these VSRs the views would be limited to glimpsed views of the
upper floors of the proposed development.
Night-time Glare
11.9.22 The visual impacts arising from the construction and operational
phases of the proposed development also relates to the potential night-time
glare effects arising from the proposed lighting apparent in views from
selected VSRs. The construction activities will not extend to night time, the
intensity, luminance and lighting levels of these activities will be low, the
night glare impact is predicted to be temporarily slight adverse to negligible.
The extent of the operational impact is dependent on the architectural design,
the disposition of the main elements of the built environment and the type of
lighting utilised particularly the lighting within the landscape. This
operational impact may be separated into two key elements, the lighting from the residential blocks and
the lighting associated with the surrounding landscape and internal access
roads / EVA.
11.9.23 The residential development landscape will not require 24 hour
lighting except for the lighting of access roads and emergency access. The intensity, luminance and lighting level
generated from residential properties is predicted to be relatively low in the
views available to the identified VSRs and in many cases the proposed
development will be seen against existing development which is also lit at
night. Impacts will also be mitigated to an extent by the viewing distances
involved. The lighting of the landscape and the internal access roads / EVA
will also be alleviated through the use of the proposed landscape buffer along
the periphery of the development and roadside planting. The potential for glare
at these lower levels can also further reduced through the use of full cut off
lighting. Impacts can be further reduced through the programming of the
lighting within the landscape in response to the proposed activities and
adjusted according to the actual need of future users. Given the adoption of
the measures described above including the focussing and shielding of light
sources to reduce glare and the careful tailoring of luminance levels within
the landscape, the night time glare impact even for the closest of the
identified VSRs in Ng Uk Tsuen and Shing Uk Tsuen is predicted to be slight.
Again these impacts will only be experienced by the residents of the village
house at the edge of the settlement (areas already illuminated with street
lighting).
11.9.24 Table 11‑7A and Figure 11‑10A presents the predicted unmitigated and mitigated
(residual) impacts for the proposed scheme during the construction and
operational phases of the project. The mitigated residual impacts are assessed
during the design year which for the purposes of this study is taken as being
between 10 and 15 years after the schemes opening when the proposed mitigation
planting is deemed to have reached a level of maturity sufficient for it to
perform the design objectives. For the purposes of this assessment low-rise was
taken as 1-10 floors, medium-rise as 11-20 floors and high-rise as 20+ floors.
Table 11‑7A Visually Sensitive Receivers and Predicted Impacts –
Option 1A
|
VSR
|
Existing View
|
Sens
|
Mag of Change (Con / Oper Phase)
|
Primary Source of Impact
|
Impact Significance Threshold
(Unmitigated)
|
Mitigation Measures
|
Impact Significance Threshold
(Mitigated)
|
|
Con
|
Oper
|
Con
|
Oper
|
|
Visually
Sensitive Receivers (VSRs)
|
|
VSR 1 - Tin Shui Wai (Tin Heng
Estate)
|
Primary
GV and PV for residents of the new developments with views to the east
although the views are long distance and likely to be severely interrupted by
future development to the north of Tin Shui Wai. The existing view extends south east across
the Hong Kong Wetland
Park to the remnant fishpond areas,
the hill slopes of Kai Shan and beyond to the hills of the Lam Tsuen
Country Park.
|
High
Type of VSRs: High-rise residential,
Residential, Permanent receivers
Population of viewers: Many
Degree
of visibility: GV
/ PV
|
Small / Small
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Small / 2000m
|
Filtered
GV views of the proposed development viewed against the green backdrop of the
Kai Shan Range.
The building height profile has been designed to mirror the existing
topography. The development will be seen in the context of the high-rise
development of Yuen Long and Tin Shui Wai.
The proposed
development, although it forms a minor component in views for these VSRs
which are dominated by Tin Shui Wai residential development in the foreground
and the existence of alternative views.
Night-time glare mitigated by viewing distance and the existing lighting from
the villages and Yuen Long in the background).
|
Moderate
Adverse
|
Moderate
Adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation CP1, OP1, OP2, and OP4.
|
Moderate
Adverse
|
Moderate
Adverse
|
|
VSR 2 - Tsim Bei Tsui
Photomontage refers to Figures 11-14A and B for Option 1A and 11-15A and B for Option 1B
|
Primary OV / PV for walkers at the lookout point south over a
landscape characterised by the estuarine mudflats and the existing fishpond
areas. Low level views are partially screened by the existing vegetation
associated with the bunds within the fishpond area whilst high level views
extend to the ridgeline to the south of the development site and beyond to
the uplands associated with the Lam
Tsuen Country
Park.
|
Medium
Type of VSRs: Lookout point, Visitors/ hikers,
Transient receivers
Population of viewers: Very few
Degree
of visibility: OV
/ PV
|
Small / Small
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Small / 2300m
|
The
proposed development will form a small component of the overall expansive OV
/ PV across the estuarine landscape. Views towards the summits of the hills
to the east and west of the proposed development site are maintained and the
proposed view corridors allow continued framed visual access to the landscape
beyond. The western and southern
sections of the view are characterised by existing high-rise development
associated with Yuen Long and Tin Shui Wai. The development facade will lead
to the loss of part of the green component of the view and disturb the
relationship between the fishponds and the saddle between the two wooded
hillsides of the Kai Shan range.
Night-time
glare effect mitigated by viewing distance and the existing lighting from the
villages and Yuen Long in the background).
|
Moderate
Adverse
|
Moderate
Adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation CP1, OP1 and OP2.
|
Moderate
Adverse
|
Moderate
Adverse
|
|
VSR 3 - Mong Tseng Wai
|
Primary
GV and PV for residents on the southern periphery of the settlement. Views
are interrupted by existing vegetation within the agricultural fields to the
south of the village and on the bunds within the fishpond areas.
|
High
Type of VSRs: Low-rise residential, Residential, Permanent
receivers
Population of viewers: Few
Degree of visibility: GV
/ PV
|
Small
to negligible / Small to negligible
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Small / 2200m
|
GV
and PV of the proposed development viewed against the green backdrop of the
Kai Shan range. The lower floors of the proposed development screened by the
intervening development and vegetation. The development will form a small
component of the overall view. The proposed view corridors through the
western part of the development will be evident in these views allowing some
visual permeability and visual access to the Yuen Long and framed by the
existing wooded hill slopes. Night-time
glare effect mitigated by viewing distance and the existing lighting from the
villages and Yuen Long in the background.
|
Slight Adverse
|
Slight Adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation CP1, OP1 and OP2.
|
Slight Adverse
|
Slight Adverse
|
|
VSR 4 - Fairview Park
|
Primary PV for residents on the western
periphery of the existing settlement. Views west extend over the Kam Tin
River Estuary and fishpond areas to the proposed development site. The
high-rise development of Tin Shui Wai forms the background to views to the
west. The structures associated with the Yuen Long Sewage Treatment Works
form a visually detracting element within these views.
|
High
Type of VSRs: Low-rise
residential, Residential, Permanent receivers
Population of viewers: Few
Degree of visibility: PV
|
Small to negligible / Small to negligible
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Small / 2400m
|
PV
and NV due to availability of other views, their orientation and the presence
of intervening development associated with the Yuen Long Sewage Treatment
Works. The development would also be seen at an acute angle and will be
partially be screened by the existing landform Kai Shan range. The proposed
visual corridors in the eastern part of the development would be evident in
views from this direction.
Due to its relatively low building profile, the
proposed development will visually integrate with the Yuen Long industrial
area. The development forms a minor component in distant views from this
location. Affected VSRs are few in numbers confined to those living at the
western boundary of Fairview
Park. Alternative views
are available from these VSRs as their major views are facing east.
Night-time glare effect is mitigated by viewing distance and the existing
lighting from the villages and Tin Shui Wai in the background)
|
Moderate to slight
adverse
|
Moderate to slight adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation CP1, OP1 and OP2.
|
Moderate to
slight adverse
|
Moderate to slight adverse
|
|
VSR 5 - Tai Sang Wai
|
Primary
GV / NV for residents on the western periphery of the existing settlement.
Views west extend over the Kam Tin River Estuary and fishpond areas to the
proposed development site. The high-rise development of Tin Shui Wai forms
the background to views to the west. The structures associated with the Yuen
Long Sewage Treatment Works form a visually detracting element within these
views and also serve in combination with the existing landform to screen low
level views of the development site.
|
High
Type of VSRs: Low-rise residential, Residential, Permanent
receivers
Population of viewers: Few
Degree of visibility: GV
/ NV
|
Small to negligible / Small to negligible
Compatibility of the project
with the surrounding landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Small / 2300m
|
GV
and NV due to the viewing angle and distances involved and the availability
of other views. The Yuen Long Sewage Treatment Works will also form the
middle ground of views towards the development site and this has degraded the
quality of the existing view. In addition the background to any views will be
formed by the high-rise development of Tin Shui Wai.
Due to the low building profile, majority of the
proposed development is partially screened by the sewage treatment plant and
existing landform. The development forms a minor component in distant views
available for these VSRs.
Night-time glare effect mitigated by viewing distance and the existing
lighting from the villages and Tin Shui Wai in the background.
|
Slight Adverse
|
Slight Adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation CP1, OP1 and OP2.
|
Slight Adverse
|
Slight Adverse
|
|
VSR 6 - Ng Uk Tsuen
Photomontage
refers to Figures11-14O and
P for Option 1A and
11-15 O and P for Option 1B.
|
Primary
OV and PV for residents on the northern periphery of the village although
views are largely screened by the existing landform and intervening
vegetation.
Primary
NV / GV for residents within the village where views are largely screened by
a combination of the existing village houses, landform and intervening
vegetation.
|
High
Type of VSRs: Low-rise residential, Residential, Permanent
receivers
Population of viewers: Few
Degree of visibility: OV
/ PV
|
Intermediate / Intermediate
(Small / Small)
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Large to medium / 200m
|
OV
and PV of the middle and upper storeys of the proposed development from
properties on the northern periphery of the development.
NV
and GV upper storeys of the proposed development from properties on the
northern periphery of the development.
Impacts due to the proximity of the proposed
development. Although many of the existing houses have views away from the
proposed development or their views are already interrupted by vegetation and
other village houses.
Night-time glare effect mitigated to an extent by existing street lighting at
the edge of the village and the screening effect of the intervening
obstacles.
|
Significant to Moderate Adverse (houses on the
northern edge of the village)
Moderate to slight adverse (houses within the
centre of the village and the open spaces)
|
Significant to Moderate Adverse (houses on the
northern edge of the village)
Moderate to slight adverse (houses within the
centre of the village and the open spaces)
|
Primary
mitigation including the architectural design and secondary mitigation CP1,
CP3, CP4, OP1, OP2, and OP4.
|
Significant to Moderate Adverse (houses on the
northern edge of the village)
Moderate to slight adverse (houses within the
centre of the village and the open spaces)
|
Significant to Moderate Adverse (houses on the
northern edge of the village)
Moderate to slight adverse (houses within the
centre of the village and the open spaces)
|
|
VSR 7 - Shing Uk Tsuen
Photomontage
refers to Figures11-14K snd L; and
Figures11-14M
and N for Option 1A.
For Option 1B refer to
Figures11-15K snd L; and Figures11-15M and N
|
Primary
PV / GV for residents on the northern periphery of the village although views
are severely interrupted by the existing landform and vegetation particularly
trees on the agricultural land at the base of the hill slope.
Primary
NV / GV for residents within the village where views are largely screened by
a combination of the existing village houses, landform and intervening
vegetation.
|
High
Type of VSRs: Low-rise residential, Residential, Permanent receivers
Population of viewers: Few
Degree of visibility: PV
/ GV
|
Intermediate / Intermediate
(Small / Small)
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Large to medium / 175m
|
PV
and GV of the middle and upper storeys of the proposed development from
properties on the northern periphery of the development.
NV
and GV upper storeys of the proposed development from properties on the
northern periphery of the development.
Impacts due to the proximity of the proposed
development. Although many of the existing houses have views away from the
proposed development or their views are already interrupted by vegetation and
other village houses.
Night-time glare effect mitigated to an extent by existing street lighting at
the edge of the village and the screening effect of the intervening
obstacles.
|
Significant to Moderate Adverse
(village
houses at the northern edge of the village)
Slight
/ Moderate Adverse
(houses
within the centre of the development and the open spaces)
|
Significant to Moderate Adverse
(village
houses at the northern edge of the village)
Slight
/ Moderate Adverse
(houses
within the centre of the development and the open spaces)
|
Primary
mitigation including the architectural design and secondary mitigation CP1,
CP3, CP4, OP1, OP2, and OP4.
|
Significant to Moderate Adverse
(village
houses at the northern edge of the village)
Slight
/ Moderate Adverse
(houses
within the centre of the development and the open spaces)
|
Significant to Moderate Adverse
(village
houses at the northern edge of the village)
Slight
/ Moderate Adverse
(houses
within the centre of the development and the open spaces)
|
|
VSR 8 - Kai Shan
|
Primary
PV / GV for walkers using the trail to the summit of Kai Shan. The available
views are interrupted and screened in some locations by the existing woodland
lining the hill slopes. Long distance views extend across the fishponds to
the Lau Fau Shan peninsular and the mudflats associated with the estuary of
the Kam Tin River.
|
Medium
Type of VSRs: Footpath, Pedestrians, Transient receivers
Population of viewers: Very
few
Degree
of visibility: PV
/ GV
|
Intermediate
/ Intermediate
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Medium to small / 800m
|
PV
and GV of the proposed development for walkers using the trail to the summit
of Kai Shan. The development would partially screen views of the fishponds to
the north although views to the north
west are already dominated by the high-rise of Tin
Shui Wai. Some views interrupted by service reservoir in the foreground, small number
of transient VSRs affected.
Night-time glare effect mitigated to an extent by existing street lighting at
the edge of the village, the viewing distance and the screening effect of the
intervening landform and vegetation.
|
Moderate Adverse
|
Moderate Adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation CP1, OP1 and OP2.
|
Moderate Adverse
|
Moderate
Adverse
|
|
VSR
9 - Long Ping Estate
|
Primary GV / NV of the existing
development site for residents on the northern periphery of the estate north
towards Kai Shan. Views beyond the ridgeline to the fishponds and the Lau Fau
peninsular are framed by the existing landform.
|
High
Type of VSRs: High-rise residential, Permanent
receivers
Population of viewers: Many
Degree of visibility: GV
/ NV
|
Small to
negligible / Small to negligible
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Small / 1700m
|
GV of the proposed upper storeys of the
proposed building blocks. Development
will form a small component of the overall view available to residents with a
north facing apartments. In addition the quality of the existing view has
been degraded by the existing level of development particularly that
associated with the Yuen Long Industrial Estate.
Night-time glare effect mitigated to an
extent by existing street lighting within the intervening villages and the
viewing distances.
|
Slight to
Moderate Adverse
|
Slight to
Moderate Adverse
|
Primary mitigation including the location
and footprint of the proposed development. Secondary mitigation OP1.
|
Slight to
Moderate Adverse
|
Slight to
Moderate Adverse
|
|
VSR 10 - Tin Tsz Estate
|
Primary
PV / GV for residents on the north east periphery of the development although
views are severely interrupted by the intervening landform. Higher-level
views extend across the fishponds to the Lau Fau Shan peninsular and the
mudflats associated with the estuary of the Kam Tin River.
|
High
Type of VSRs: High-rise residential, Permanent receivers
Population of viewers: Intermediate
Degree
of visibility: PV
/ GV
|
Small to negligible / Small to negligible
Compatibility of the project with the surrounding landscape:
Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Small / 1500m
|
PV
and GV of the upper storeys of the proposed development partially screened by
the existing landform of the summit of Kai Shan. The existing view is
degraded to an extent by the development associated with the northern part of
Yuen Long and the modifications made to the hill slopes of Kai Shan during
the construction of the service reservoir.
Therefore only VSRs living at the elevated floors
will have GV of the upper floors of the development. Alternative views are
available from these VSRs.
Night-time glare effect is mitigated to an extent by existing street lighting
in development s such as Fairview Park,
the screening effect of the intervening obstacles and the viewing distances.
|
Slight to Moderate Adverse
|
Slight to Moderate Adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation OP1.
|
Slight to Moderate Adverse
|
Slight to Moderate Adverse
|
|
VSR 11 – Kenswood Court
Photomontage refers to Figures11-14 I and J for
Option 1A and 11-15 I and J
for Option 1B.
|
Primary
PV / GV for residents on the north east periphery of the development although
views are severely interrupted by the intervening landform. Higher level
views extend across the fishponds to the Lau Fau Shan peninsular and the
mudflats associated with the estuary of the Kam Tin River.
|
High
Type of VSRs: High-rise residential, Permanent receivers
Population of viewers: Intermediate
Degree
of visibility: PV
/ GV
|
Small
/ Small
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Small / 1000m
|
PV
and GV of the proposed development partially screened by the existing
landform of the Kai Shan range. In this view the narrowest elevation of the
proposed development would be visible thus minimising its apparent scale
within the landscape. In addition the proposed view corridors through the
western portion of the proposed development would be evident in these views.
Therefore the development forms a minor component in views looking towards
Kai Shan and Pat Shi Leng. Affected VSRs limited to people living in Kenswood Court
with views looking towards the Yuen Long industrial area. Their visual access
looking towards the knoll adjacent to
Ng Uk Tsuen will be partially screened by the development.
However, views looking towards the knoll in the foreground and Pat Sin Leng
in the background will not be affected by the development. Night-time glare
effect mitigated to an extent by existing street lighting in developments
such as Fairview Park,
the screening effect of the intervening obstacles and the viewing distances.
|
Moderate Adverse
|
Moderate Adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation OP1.
|
Moderate Adverse
|
Moderate Adverse
(Mitigation measures including building design
and disposition plus landscape mitigation effective in partially mitigating
impacts).
|
|
VSR 12 -
Tin Yuet
Estate,
Tin Shui Wai
|
Primary
PV for residents on the eastern side of the development across the Hong Kong Wetland
Park
towards the proposed development site. Long distance views extend over the Kam Tin River estuary towards the uplands of the Lam Tsuen
Country Park.
|
High
Type of VSRs: High-rise residential, Permanent
receivers
Population of viewers:
Intermediate
Degree of visibility: PV
|
Small
/ Small
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Small / 1500m
|
PV
for residents in the elevated floors on the eastern side of the developments
with views of the Study Area. As with 11 above the smallest elevation of the
development and the view corridors in the western portion of the proposed
development will be visible minimising the potential visual intrusion caused
by the scheme. In addition the
proposals make up a small part of the overall view. Night-time glare effect
mitigated to an extent by existing street lighting at the edge of the
adjacent villages and the viewing distances.
Cumulative
impacts due to the future planned residential development at Area
103 and 104 in their
foreground, the cumulative impact are therefore not significant with
landscape mitigation measures fully established.
|
Moderate
Adverse
|
Moderate
Adverse
|
Primary mitigation including the location
and footprint of the proposed development Secondary mitigation OP1.
|
Moderate
Adverse
|
Moderate Adverse
(Mitigation measures including building design
and disposition plus landscape mitigation effective in partially mitigating
impacts).
|
|
VSR 13 – Hong Kong Wetland
Park
Photomontage refer to Figure 11-14E and F for
Option 1A and 11-15E and F for
Option 1B.
|
Primary
GV and PV for visitors to the wetland south towards the development site. The
views will be interrupted to an extent by the existing and proposed
vegetation associated with the park and the fishpond bunds. The ridgeline to the south of the
development site forms a green
back drop to the flat estuarine plain. The uplands of the Lam Tsuen
Country Park
form the background to longer distance views.
|
Medium
Type of VSRs: Visitor Centre and facilities, visitors and
staff, Transient receivers
Population of viewers:
Intermediate
Degree of visibility: GV / PV
|
Small / Small
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Medium to small / 1300m
|
GV
and PV due to the proposed buffer woodland planting for HKWP. Low level views
would also be partially screened by the existing trees located on the
fishpond bunds. The proposed development would form a small component of the
overall views available being visible just above the horizon formed by the
vegetation.
Night-time
glare effect mitigated to an extent by existing street lighting in the
surrounding development particularly Tin Shiu Wai and the backdrop formed by
Yuen Long , the viewing distance and a combination of the low lying nature of
the VSR and the screening effect of intervening vegetation.
|
Moderate
Adverse
|
Moderate Adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation CP1, OP1 and OP2.
|
Moderate Adverse
|
Moderate Adverse
|
|
VSR 14 – Vianni Cove,
Tin Shui Wai North
Photomontage refer to Figures11-14G
and H for Option 1A and
11-15G and H.
|
Primary
PV / GV for residents on the north east periphery of the development although
low level views are severely interrupted by the intervening landform and
vegetation. Higher level views extend across the fishponds to the Lau Fau
Shan peninsular and the mudflats associated with the estuary of the Kam Tin
River. The uplands of the Lam Tsuen
Country Park
form the background to longer distance views.
|
High
Type of VSRs: High-rise residential,
Residential, Permanent receivers
Population of viewers:
Intermediate
Degree of visibility:
PV / GV
|
Small
/ Small
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Medium to small / 1200m
|
PV
and GV of the eastern side
of the development although low-level views would be
largely screened by the existing vegetation on the existing fishpond bunds
and the Open Space at
Area
120. The proposed development forms a minor component of the wide panoramic
views and will be seen against the backdrop of Ng Uk Tsuen and the Yuen Long
industrial area. Although views looking towards the knoll adjacent to Ng Uk Tsuen will be partially
screened, alternate views are available from these VSRs.
Night-time
glare effect is mitigated to an extent by existing street lighting in
villages / Yuen Long to the south of the proposed development and the viewing
distance.
Potential
cumulative impact due to the
development of the CDA development at Area 115 which will form foreground to views.
|
Moderate Adverse
|
Moderate Adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation OP1 and OP2.
|
Moderate Adverse
|
Moderate
Adverse
(Mitigation measures including building design
and disposition plus landscape mitigation effective in partially mitigating
impacts).
|
|
VSR 15 - Grandeur
Terrace, Tin Shui Wai North
|
Primary
PV for residents on the eastern side of the development across the Hong Kong
Wetland Park
towards the proposed development site. Long distance views extend over the Kam Tin River estuary towards the uplands of the Lam Tsuen
Country Park.
|
High
Type of VSRs: High-rise residential,
Residential, Permanent receivers
Population of viewers:
Intermediate
Degree of visibility: PV
|
Small
/ Small
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Small / 1600m
|
PV
for residents on the elevated floors on the eastern side of the developments
with views of the Study Area. This area on the north-eastern side of the Tin
Shui Wai New Town (Area 103) is intended as a high-density development. Residents
are likely to have elevated views of the development proposals although it
would form a relatively small component of the overall view available and at
a viewing distance both factors which will minimise potential impacts.
The
views looking towards the knoll adjacent to Ng Uk Tsuen will be partially screened in the
visual context of Yuen Long industrial area.
Night-time
glare effect mitigated to an extent by existing street lighting in villages
to the south of the proposed development and the viewing distances.
|
Moderate Adverse
|
Moderate Adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation OP1 and OP2.
|
Moderate Adverse
|
Moderate
Adverse
(Mitigation measures including building design
and disposition plus landscape mitigation effective in partially mitigating
impacts).
|
|
Planned Visually Sensitive Receivers
|
|
PVSR A1 – Comprehensive Development Area
|
Primary
NV and GV for future residents of site 115 to the northwest of the proposed
development area. Low-level views of the development area would be screened
by the existing intervening vegetation and the planting associated with the
proposed open spaces and the Hong
Kong Wetland Park on the eastern periphery of Tin
Shui Wai.
|
High
Type of VSRs: Medium-rise residential, Residential, Permanent
receivers
Population of viewers: Intermediate
Degree
of visibility: NV
and GV
|
Medium to small
/ Medium to
small
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Small / 1000m
|
NV
and GV for future residents with views from the upper storeys of the proposed
development in properties on the eastern periphery of area 115. Due to viewing distance, the development forms a
minor component in views and will be seen against Ng Uk Tsuen and the Yuen
Long industrial area. This assessment is based on the assumption that this
CDA will be completed before the proposed development. If the proposed
development is in place first, negligible impact is expected from these VSRs
as the baseline condition will have changed.
Night-time
glare effect mitigated to an extent by existing street lighting in villages
to the south of the proposed development and the viewing distances.
|
Moderate Adverse
|
Moderate Adverse
|
Primary
mitigation including the location and footprint of the proposed development.
Secondary mitigation CP1, OP1 and OP2.
|
Moderate
Adverse
|
Moderate Adverse
|
|
|
|
|
|
|
|
|
|
|
|
Key
Landscape
Sensitivity (Sens): Low, Medium or High
Population
of viewers:
Very Few, Few, Intermediate or High
Magnitude
of Change (Mag): Negligible, Small, Intermediate and Large
Compatibility
of the project with the surrounding landscape: Low, Medium or High
Reversibility
of change: Irreversible or Reversable (Changes may be reversed if the
development were removed).
Scale
and distance of the impact: Small, Medium or Large
The
viewing distance is measured from the façade of the building or location that
forms the Visually Sensitive Receiver to nearest visible part of the proposed
scheme.
Degree of Visibility /
Extent of the View Occupied by the Development:
NV no view; (or difficult to
perceive);
GV glimpse: a transient view or
distant view in the context of the wider landscape, or scope of the view;
PV partial view: a clear view of
part of the site; a partial view of most of it; or a distant view in which the
site forms a relatively small section of a wider view; and
OV open view: a panoramic view of
most of the site, occupying most of the field of vision.
Significance Threshold: Negligible, Slight, Moderate and
Significant (adverse or beneficial)
Residual Impacts: Refer to matrix and table in
methodology section
Con: Construction phase impacts
Oper: Operational phase impacts
Visual Impacts: Option 1B
Views from Residences
11.9.25 The potential visual impacts arising from Option 1B will be broadly
similar to those identified for Option 1A.
The main differences are likley to be for the residents of Ng Uk Tsuen (VSR 6)
and Shing Uk Tsuen (VSR 7) (approximately 10 houses in each case) living at the
northern periphery of the villages with windows facing north to the development
site will experience a similar level of impact (moderate to significant
adverse) to that predicted for Option 1A.
Again views from many of these village houses are partially obstructed by the
existing landform, vegetation and structures. For other residents of the
villages, pedestrians within open spaces and vehicle travellers the impacts are
likely to be slight adverse due to the screening effect of adjacent village
houses, the angle and viewing distance, and the proximity of existing
vegetation. This is less significant than the impacts which are likely to
accrue from Option 1A due
largely to the reduced building height, although there will still be some
glimpsed views of the upper floors of the proposed development.
Views for travellers on Public Roads and Railways
11.9.26 The potential visual impacts for vehicle travellers on the roads
which run through Ng Uk Tsuen (VSR 6) and Shing Uk Tsuen (VSR 7) are likely to
be slight to moderate adverse due to their transient nature, the screening
effect of adjacent village houses and vegetation, and the angle and viewing
distance. For these VSRs the views would be limited to glimpsed views of the
upper floors of the proposed development.
Night-time Glare
11.9.27 Due to the broadly similar characteristics of both development
options 1A and 1B and the
asdoption of the mitigation measures described in this report the potential
glare impacts at night time will be the same as those described for Option 1A.
11.9.1
Table 11‑7B and Figure 11‑10B presents the predicted unmitigated and mitigated
(residual) impacts for the proposed scheme during the construction and
operational phases of the project. The mitigated residual impacts are assessed
during the design year which for the purposes of this study is taken as being
between 10 and 15 years after the schemes opening when the proposed mitigation
planting is deemed to have reached a level of maturity sufficient for it to
perform the design objectives. For the purposes of this assessment low-rise was
taken as 0-10 floors, medium-rise as 11-20 floors and high-rise as 20+ floors. The table highlights the main differences in
the potential impacts between Options 1A
and 1B.
Table 11‑7B Visually Sensitive Receivers and Predicted Impacts –
Option 1B
|
VSR
|
Existing
View
|
Sens
|
Mag
of Change (Con / Oper Phase)
|
Primary
Source of Impact
|
Impact
Significance Threshold
(Unmitigated)
|
Mitigation
Measures
|
Impact
Significance Threshold
(Mitigated)
|
|
Con
|
Oper
|
Con
|
Oper
|
|
Visually Sensitive Receivers (VSRs)
|
|
VSR 6 - Ng Uk Tsuen
Photomontage refers to
Figures11-15O and P
|
Primary
OV and PV for residents on the northern periphery of the village although
views are largely screened by the existing landform and intervening
vegetation.
Primary
NV / GV for residents within the village where views are largely screened by
a combination of the existing village houses, landform and intervening
vegetation.
|
High
Type of VSRs: Low-rise residential, Residential, Permanent
receivers
Population of viewers: Few
Degree of visibility: OV
/ PV
|
Intermediate / Intermediate
(Small / Small)
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Large to medium / 200m
|
OV
and PV of the middle and upper storeys of the proposed development from
properties on the northern periphery of the development.
NV
and GV upper storeys of the proposed development from properties on the
northern periphery of the development.
Impacts due to the proximity of the proposed
development. Although many of the existing houses have views away from the
proposed development or their views are already interrupted by vegetation and
other village houses.
Night-time glare effect mitigated to an extent by existing street lighting at
the edge of the village and the screening effect of the intervening
obstacles.
|
Significant to Moderate Adverse (houses on the
northern edge of the village)
Slight adverse (houses within the centre of the
village and the open spaces)
|
Significant to Moderate Adverse (houses on the
northern edge of the village)
Slight adverse (houses within the centre of the
village and the open spaces)
|
Primary
mitigation including the architectural design and secondary mitigation CP1,
CP3, CP4, OP1, OP2, and OP4.
|
Significant to Moderate Adverse (houses on the
northern edge of the village)
Slight adverse (houses within the centre of the
village and the open spaces)
|
Significant to Moderate Adverse (houses on the
northern edge of the village)
Slight adverse (houses within the centre of the
village and the open spaces)
|
|
VSR 7 - Shing Uk Tsuen
Photomontage refers to
Figures11-15K and L
Photomontage
refers to Figures11-15M
and N
|
Primary
PV / GV for residents on the northern periphery of the village although views
are severely interrupted by the existing landform and vegetation particularly
trees on the agricultural land at the base of the hill slope.
Primary
NV / GV for residents within the village where views are largely screened by
a combination of the existing village houses, landform and intervening
vegetation.
|
High
Type of VSRs: Low-rise residential, Residential, Permanent receivers
Population of viewers: Few
Degree of visibility: PV
/ GV
|
Intermediate / Intermediate
(Small / Small)
Compatibility of the project with the surrounding
landscape: Medium
Duration of impacts: Construction stage – Temporary
Operational Stage – Permanent
Reversibility of change: Irreversible
Scale and distance of the
impact: Large to medium / 175m
|
PV
and GV of the middle and upper storeys of the proposed development from
properties on the northern periphery of the development.
NV
and GV upper storeys of the proposed development from properties on the
northern periphery of the development.
Impacts due to the proximity of the proposed
development. Although many of the existing houses have views away from the
proposed development or their views are already interrupted by vegetation and
other village houses.
Night-time
glare effect mitigated to an extent by existing street lighting at the edge
of the village and the screening effect of the intervening obstacles.
|
Significant to Moderate Adverse
(village
houses at the northern edge of the village)
Slight
Adverse
(houses
within the centre of the village and the open spaces)
|
Significant to Moderate Adverse
(village
houses at the northern edge of the village)
Slight
Adverse
(houses
within the centre of the village and the open spaces)
|
Primary
mitigation including the architectural design and secondary mitigation CP1,
CP3, CP4, OP1, OP2, and OP4.
|
Significant to Moderate Adverse
(village
houses at the northern edge of the village)
Slight
Adverse
(houses
within the centre of the village and the open spaces)
|
Significant to Moderate Adverse
(village
houses at the northern edge of the village)
Slight
Adverse
(houses
within the centre of the village and the open spaces)
|
Key
Landscape
Sensitivity (Sens): Low, Medium or High
Population
of viewers:
Very Few, Few, Intermediate or High
Magnitude
of Change (Mag): Negligible, Small, Intermediate and Large
Compatibility
of the project with the surrounding landscape: Low, Medium or High
Reversibility
of change: Irreversible or Reversable (Changes may be reversed if the development were removed).
Scale
and distance of the impact: Small, Medium or Large
The
viewing distance is measured from the façade of the building or location that
forms the Visually Sensitive Receiver to nearest visible part of the proposed
scheme.
Degree of Visibility /
Extent of the View Occupied by the Development:
NV no view;
(or difficult to perceive);
GV glimpse:
a transient view or distant view in the context of the wider landscape, or
scope of the view;
PV partial view: a clear view of part of the site; a partial view of most of it; or
a distant view in which the site forms a relatively small section of a wider
view; and
OV open view:
a panoramic view of most of the site, occupying most of the field of vision.
Significance Threshold: Negligible, Slight, Moderate and
Significant (adverse or beneficial)
Residual Impacts: Refer to matrix and table in
methodology section
Con: Construction phase impacts
Oper: Operational phase impacts
11.10
Cumulative Impacts
11.10.1 A number of projects are planned within the Study Area, which will
result in landscape and visual impacts including the degradation of landscape
character and visual amenity, and the loss of landscape resources.
11.10.2 Mitigation measures to address landscape and visual impacts have
been incorporated into the design of each of the approved projects. The
resulting changes to the existing landscape character, landscape resources and
visual amenity have been taken into account in the baseline assessment.
Cumulative impacts from these projects are therefore taken into account through
their inclusion in the baseline conditions for this EIA.
11.10.3 Section 2.3 of the EIA Report lists the concurrent projects which
would potential lead to cumulative impacts whilst Figure 2-12 shows their
location. These concurrent projects include the Yuen Long and Kam Tin Sewerage
and Sewage Disposal Stage 2 particularly in respect of the proposed twin rising
mains which will follow an alignment along the southern boundary of the
proposed development site. As discussed in Section 2.3, there is likely to be negligible cumulative impact during the
construction and operational phases.
11.10.4 The development of the CDA sites to the northeast of Tin Shui Wai
will also contribute to a cumulative impact in the local area with the
transformation of largely rural views for the adjacent VSRs to something more
urban in character. However it may be argued that the construction of medium
and low-rise development along the urban edge will serve to provide a more
subtle integration of the existing high-rise development into its landscape and
visual setting.
11.10.5 The construction of the Hong
Kong Wetland Park has been completed and therefore
will not lead to cumulative landscape and visual impacts for the two projects.
In terms of the operational phase cumulative impacts it is likely that the
combined affect of the two projects will not significantly increase the impacts
predicted for the development at Fung Lok Wai in isolation.
11.10.6 Therefore the cumulative impact of the concurrent proposals
identified above will not lead to a further degradation of either the landscape
character or visual amenity of the Study Area beyond that predicted for the
development proposals.
11.11.1 The landscape mitigation measures described in this report are at a
level which both demonstrates their ability to alleviate the potential
landscape and visual impacts identified in the assessment and also to allow the
proposals to be carried forward during the detailed design stage. The measures
proposed for Options 1A and
1B adopt the same approach. More detailed landscape proposals will be developed
during the initial stages of the design and construction phase of this project
following the completion of the detailed Tree Survey Report. The measures are
designed to address both the construction and operational phases of the
project.
11.11.2 The landscape and visual
mitigation measures are described both in a generic sense for measures, which
apply to all of the development site and in terms of the proposed landscape
strategy for the amenity areas within the development. The aim of the
mitigation measures is to:
·
Alleviate where possible those
landscape and visual impacts which are unavoidable through the option selection
process including the site planning for the footprint and height profiles;
·
Establish a coherent and
integrated landscape framework for the development site drawing together the
visually disparate components of the proposed development;
·
Enhance the existing landscape
and visual context of the surrounding areas providing integration between the
development and its context; and
·
Provide a co-ordinated approach
between the ecological and landscape mitigation proposals where there is an
interface.
11.11.3 The Design Concept Drawing presented as Figure 11‑11A and 11-12A
demonstrates the main landscape and visual mitigation strategies while Figure
11-12B and 11-12B Landscape Master Plan and Figure 11- 13 A,B,C and D Sections
show the proposed landscape treatment for both the proposed housing
development.
11.11.4 It is recommended that the Environmental, Monitoring and Audit
Requirements (EM&A) for landscape and visual resources described in Section
16 of this report is undertaken during both the construction and operational
phases of the project.
Primary Mitigation Measures
11.11.5 In accordance with the EIAO TM, the hierarchy for landscape and
visual impact mitigation is first avoidance of impact, then minimisation of
impact and finally compensation of impact. As has been described in Section 3
and Section 11.4 above the selection of the preferred scheme option has been
undertaken to fulfil the following objectives:
·
Minimisation of the cumulative
impact, as far as possible, to the landscape through for example the
maintenance of the green buffer between the proposed development site and the
existing and proposed high-rise development associated with the Tin Shui Wai
development. In both options 1A
and 1B the affectivity of the green buffer has been further enhanced through
the movement of the development footprint a further 150m to the east;
·
Protection of areas of high
landscape quality including the green backdrop formed by the existing Kai Shan
range which is an important component in existing and proposed views from the
Tin Shui Wai development;
·
Maintenance of the unique
landscape character of the Study Area as a resource for the HK SAR, this is
apparent in the proposed mitigation measures for the proposed development
whereby impacts to the large part of the existing fishpond area have been
avoided through the location of the development on its southern periphery; and,
·
Rehabilitation and enhancement
of existing landscapes following the completion of the construction phase of
the project, this will be apparent in the enhancement of the fishpond areas to
the north of the proposed development site.
11.11.6 In accordance with the EIAO TM, mitigation measures for the
construction and operational phases of the development have been designed to
minimise predicted landscape and visual impacts, and to compensate for lost
landscape resources as far as is possible given the project constraints.
Secondary Mitigation Measures
11.11.7 A series of mitigation measures designed to alleviate impact and
where possible compensate for loss of landscape resources, change of landscape
character and visual amenity for VSRs resulting from the construction and
operational phases of the project are described in Table 11‑5 to Table
11‑7 and Table
11‑8 to Table
11‑9 below. The measures are common to both Options 1A and 1B. The implementation and funding
of the amenity landscape areas associated with the proposed residential
development will be undertaken by the project proponent, and the subsequent
management and maintenance will be undertaken by the owners. The exception to
this will be the improvements to the Southern Development Access., i.e. the
existing Fuk Shun Street.
These improvements will be funded and implemented by the project proponent
although the management and maintenance of the soft landscape for the improved
access will remain at the responsibility of the Leisure and Cultural Services
Department and all hardworks at the responsibility of Highways Department. Both
departments have agreed in principle to continue their responsibility for the
management and maintenance of the improved access. The management and maintenance of the
proposed Wetland Nature Reserve will be undertaken by the project proponent or its designated successor e.g. an independent
Foundation taking over the long term management of the WNR upon the
Government’s approval.
Table 11‑8 Proposed Construction Phase
Mitigation Measures
|
Mit. Code
|
Mitigation Measure
|
|
CP1
|
Preservation of Existing Vegetation -
The development proposals would avoid disturbance to the existing trees as
far as practicable within the confines of both the development site, Southern
Development Access and the proposed Wetland Nature Reserve (WNR). It is
recommended that a full tree survey and felling application will be
undertaken and submitted for approval by the relevant government departments
in accordance with ETWB TCW No. 3/2006 Tree Preservation during the
detailed design phase of the project. Where possible all trees which are not
in conflict with the proposals would be retained and shall be protected by
means of fencing where appropriate to prevent potential damage to tree
canopies and root zones from vehicles and storage of materials.
Specifications for the protection of existing trees will be circulated for
approval by the relevant government authorities during the preparation of the
detailed tree survey.
|
|
CP2
|
Preservation of Existing Topsoil - Topsoil
disturbed during the construction phase will be tested using a standard soil
testing methodology and where it is found to be worthy of retention stored
for re-use. The soil will be stockpiled to a maximum height of 2m and will be either temporarily
vegetated with hydroseeded grass during construction or covered with a
waterproof covering to prevent erosion. The stockpile should be turned over
on a regular basis to avoid acidification and the degradation of the organic
material, and reused after completion. Alternatively, if this is not
practicable, it should be considered for use elsewhere, including other
projects.
|
|
CP3
|
Development Site and Temporary Works Areas
- The landscape of these works areas would
be restored following the completion of the construction phase. Construction
site controls shall be enforced, where possible, to ensure that the landscape
and visual impacts arising from the construction phase activities are
minimised including the storage of materials, the location and appearance of
site accommodation and the careful design of site lighting to prevent light
spillage. Screen hoarding may not be a practicable for this project due to
the viewing distances involved and the elevated viewing position of the
majority of VSRs.
|
|
CP4
|
Mitigation Planting - Replanting of disturbed vegetation should be
undertaken at the earliest possible stage of the construction phase of the
project and this should use predominantly native plant species. All imported
plants should be quarantined in local nursery for a minimum of 1 month to
check there are no symptoms of infection by pests or diseases prior to
planting on site. It is proposed that the origin of the trees be
established through site visits to the nursery. In addition, certain trees will be brought to a temporary holding nursery
at a small size as early in the construction period as possible and grown to
the semi-mature size required as part of the proposed mitigation planting.
This nursery will be located either on site or within the local area.
|
|
CP5
|
Transplantation of Existing Trees - Existing trees to be transplanted as shown in the
Landscape Master Plan (approximately
28 trees), final recipient site will subject to the findings of the detailed
tree survey and felling application undertaken at the detailed design stage
|
Table 11‑9 Proposed Operational Phase Mitigation
Measures
|
Mit. Code
|
Mitigation Measure
|
|
OP1
|
Design of Built Development - the proposed residential development will incorporate
design features including:
·
Stepped building height
principle – The proposed
residential blocks for Option 1A
will range in height from 14 to 18 floors fronted by low-rise buildings in
order to provide a greater sense of visual integration with the existing
landscape context and mirror the form of the existing landform particularly
the ridgeline to the south of the development site. The proposed built form
will also provide a more visually interesting architectural form contrasting
with the abrupt nature of the existing development associated with Tin Shui
Wai. Whereas Option 1B will adopt a common height (15 storeys) for the blocks
which will also be fronted by low-rise buildings which also serve to enhance
the development’s visual integration.
·
Building massing and
permeable development facade - the proposed use of slightly higher building blocks for
Option 1A has allowed the
incorporation of significant view corridors and the creation of voids in the
façade of each of the blocks allowing views through the development to the
green backdrop formed by the wooded hillsides to the south. These view
corridors and viods within the façade of each block also allow the
development to avoid the walling effect evident in the existing developments
to the south and west particularly when viewed from locations such as the
development in the northern part of Tin Shui Wai. The adoption of a slightly
lower building height for Option 1B will require the introduction of one
additional block and a subsequent reduction in the width of the proposed view
corridors.
·
Maintenance of existing
ridgeline and green backdrop – the proposed development form allows the maintenance of
the existing ridgeline and green backdrop to the south of the development
site even in relatively close views. This is achieved in Options 1A and 1B through a combination of
the building heights and the creation of the view corridors.
·
Colour treatment of
building facades - the architectural design for both Option 1A and 1B seeks to reduce the
apparent visual mass of the development further through the use of colour
blocking utilising range of visually recessive earth colours and tones on the
facades of the different blocks.
·
Underground car parking - the proposed development for Options 1A and 1B will utilise underground car parking in
order to maximise the area available for landscaping and minimise potential
impacts of extensive hard surfaced areas in elevated views both within and
without the development site.
·
Responsive building finishes - In terms of the building finishes for Options 1A and 1B natural tones should be
considered for the colour palette with non-reflective finishes are
recommended on the outward facing building facades to reduce glare
effect.
·
Responsive lighting design – Aesthetic design of architectural and road lighting
with following glare design measures:
o
Directional and full cut off lighting is recommended
particularly for recreation and roadside areas to minimise light spillage to
the surrounding areas.
o
Minimise geographical spread of lighting, only applied for
safety at the key access points and staircases;
o
Limited lighting intensity to meet the minimum safety and
operation requirement; and
o
High pressure sodium road lighting is recommended for more
stringent light control reducing spillage and thus visual impacts.
|
|
OP2
|
Landscape Buffer Planting – According to the guidelines provided in the Final
Report of the Fish Pond Study at Deep Bay Area, the buffer area will extend
around the periphery of the development to the proposed marsh habitat in WNR
providing screening of the development at low levels and creating a
transitional structure, not less than 50m
wide, between the low-lying fishponds of the WNR and the upright forms of the
proposed built development. This planting in addition to the proposed bamboo
planting proposed as part of the ecological mitigation measures will also
serve to visually integrate the proposals into the existing landscape
framework. The buffer will utilise
native tree species to link where possible to the existing wooded areas with
the advantage of creating a more coherent landscape framework whilst also
improving the ecological connectivity between existing woodland habitats. A
woodland management programme will be employed during the operational phase
of the project with the objective of conserving and enhancing the ecological
interest (approximate area 3750 square metres equating to 750 trees at 2.5m planting centres).
Apart from the landscape buffer planting, some limited
tree clusters will be planted on bunds within the WNR to facilitate the establishment of habitat for different
bird species. The primary objective of the tree planting within the WNR will be ecological in the creation of a favourable
habitat for birds rather than for amenity purposes. As such within the
fishpond or freshwater marshland area, trees will be planted in small
clusters in positions designed not to intrude upon the bird flight lines,
create enclosure or shade the marshland and fishponds. Some fruit-bearing
trees, such as Ficus hispida, Ficus microcarpa and Melia azedarach, are recommended from
ecological perspectives to enhance foraging opportunities for some bird
species. Whilst wide canopied tree species such as Ficus microcarpa in combination with bamboo species such as Bambusa eutuldoides are recommended to
be planted at the edge of the alternative egretry I in order to provide a
favourable habitat for the egrets and screen the area from human activity.
|
|
OP3
|
Landscape Strategy for
the Design of Amenity Space - The proposals are
described in detail below (approximate area 3.4 ha).
|
|
OP4
|
Compensatory
Planting Proposals - the planting proposals for the residential
amenity areas and landscape woodland buffer areas presented as Figure 11-12,
Landscape Master Plan include some 300 new specimen trees in addition to the
3750 square metres of mass woodland planting described under OP2 above would
be established within the project boundary. The proposed planting of some
1050 trees will result in a compensatory planting ratio of 2.6:1 (new tree
planting: trees recommended for felling). This compares favourably with the
report's assertion that some 399 trees would be felled due to the proposals
in this area. Following the retention of existing trees, the successful
establishment of newly planted trees and the transplantation of some of the
existing trees, the project area will contain approximately 1316 trees. Trees
forming part of the landscape buffer area will utilise species native to Hong Kong while the species selection for the areas
within the development site will respond to the landscape concept for the
area. These proposals will be subject to the detailed design stage of the
project.
|
|
OP5
|
Southern Development
Access – the landscape of the road corridor will be restored to its existing
condition following the completion of the road enhancement works.
|
Landscape Strategy
11.11.8 The Landscape Master Plan (LMP) is for Option 1A presented as Figure
11‑11B and with supporting sections presented as Figure 11‑13 A and B; and Option 1B as Figure 11‑12B and Figure
11‑13C and D respectively. The design of the amenity
landscape areas has the following landscape design objectives:
·
Provide a quality outdoor
environment for the future residents providing for their future recreational
needs including outdoor active and passive recreational facilities;
·
To maximise the area of
vegetation particularly tree planting within the development site to enhance
the environmental quality of the development. The use of extensive use of
planting will also create shade serving to reduce the solar gain of the hard
surfaces particularly the hard paved areas and building facades; and
·
Create a landscape buffer
through the combination of the proposed woodland and marsh buffer planting, not
less than 50m
wide, providing a measure of landscape and visual integration in elevated views
of the scheme proposals and providing screening and softening of the built form
in low level views.
11.11.9 The Landscape Master Plan comprises a series of elements that
respond to the future requirements of the users. The proposed landscape
treatments that comprise the Landscape Master Plan have for the purposes of
this description have been separated into treatments or approaches.
Landscape Design Concept
11.11.10
The landscape design concept
for both Options 1A and 1B is
divided into two different components the landscape design for residential
development and the buffer planting areas. The concept provides a synthesis
between a contemporary design philosophy and sustainable development
principles. The spatial hierarchy involves movement from the public areas to
more intimate spaces. The proposed clubhouse, swimming pool and roundabout
courtyard form the central focus for residents within the development. The
roundabout courtyard acts as gateway to the development establishing a sense of
arrival and setting the tone for the overall development. The clubhouse is the
social focus of the development and hence is also the most public of the open
spaces. Moving away from the clubhouse
the open space network incorporates a number distinct spaces created through
the orientation of the built form and through the use of planting which create
a series of outdoor rooms. These rooms accommodate both active informal
recreation in the form of for example children’s play areas and more passive
pursuits such as the proposed seating area within the Sculpture Garden.
Option 1A also
incorporates Sky Gardens within each of the proposed
development blocks designed to create an additional level of open space for the
future residents and maximise the amount of visible greenery. Each of these
spaces will be imbued with an individual character through the use of for
example distinctive paving and street furniture, and planting combinations.
11.11.11
The landscape of both options
will essentially be a vehicle free environment being designed for the
pedestrian with the car parking being located in a basement below the landscape
area. The layout of the space and interconnected footpaths is designed to be
legible with visual access between nodes and distinct entrance courtyards to
the individual development blocks.
11.11.12
The buffer planting is provided
along the edge of the residential development extending to the north in
association with the marsh habitat created under the WNR. Both woodland edge
planting and the marsh habitat form part of the landscape design framework in
associated with the orientation of open lawn and local open space designed
under the development. The design of the landscape buffer follows the
guidelines suggested in the Study as discussed in Section 11.6.
Planting Design – Main Residential Area
11.11.13
The landscape of the proposed
development area for both options will utilise ornamental tree species,
flowering shrubs and foliage plants, which provide both, colour highlights and
seasonal variation. These soft landscape measures will ensure that the hard
lines of the built form are visually softened in views from without the
development site and in elevated views from the proposed residential blocks.
Trees are proposed along the edge of the development site to provide a soft
planted edge and provide some visual integration with the surrounding
landscape. In order to ensure that these planting proposals are feasible it is
proposed that an adequate planting medium be incorporated into the design of the
soft landscape areas. For example a minimum 1.5m depth of planting medium will be incorporated
into the design proposals, facilitating the planting of trees and palms in this
area and 0.65m will be required
for shrub areas. The use of semi-mature tree planting would be encouraged to
provide a more instant effect. Species
would be selected to provide visual and aesthetic interest throughout the year
through foliage and flower form and colour.
11.11.14
The plant species for the
landscaped areas will provide colour throughout the year with seasonal
variation. This is achieved through the selection of species with an
interesting form, colour and texture of their foliage and through the use of
flowering species to provide an architectural highlight including Bauhinia blakeana,
Delonix regia, Crataeva religiosa, Lagerstroemia indica, Ficus microcarpa,
Cassia surratensis, Archontophoenix alexandrae, Jacaranda acutifolia and Bombax
malabaricum.
Planting Design – Landscape Buffer Area
11.11.15
The landscape buffer serves as
a major landscape mitigation measures as discussed in Table 11-9. The proposals
shown on Figure 11-13 A,B,C
and D, the landscape buffer will be effectively formed by a combination of
continuous marsh habitat approaching the reserved fish ponds, bamboo planting
adjacent to an approximately 2m
high security fence, and mass woodland and shrub planting on a 2m high berm adjacent to the open spaces
within the development. The extent of landscape buffer has been maximised with
limited site formation associated with the development to avoid further
disturbance to the fish pond area. This buffer is designed in accordance with
the guidelines suggested in the Final Report of Fish Pond Study in Deep Bay
Area.
11.11.16
The planting proposals will
enhance ecological value through the creation of marsh and woodland within the
buffer area between the WNR and development. The species selection for the
proposed landscape woodland buffer would centre on the use of largely native
species which have an ecological benefit in addition to the proposed mitigation
of the predicted landscape and visual impacts. The species choice will reflect
the range of existing species disturbed on the existing valley floor including
Celtis tetrandra subsp. Sinensis, Ficus hispida, Ficus microcarpa, Litsea glutinosa,
Macaranga tanarius and Mallotus paniculatus.
11.11.17
Apart from the woodland buffer
planting, some tree clusters will be planted in a number of limited locations
upon the bunds within the WNR to broaden the range of habitat for different
bird species. The primary objective of the tree planting within the WNR will be
ecological in the creation of a favourable habitat for birds rather than for
amenity purposes. Following this approach trees will be planted in small
clusters in positions designed not to intrude upon the bird flight lines,
create enclosure or shade the marshland and fishponds. Some fruit-bearing
trees, such as Ficus hispida, Ficus microcarpa and Melia azedarach, are
recommended from an ecological perspective to enhance foraging opportunities
for some bird species. Whilst wide canopied tree species such as Ficus
microcarpa in combination with bamboo species such as Bambusa eutuldoides are
recommended to be planted at the edge of the alternative egretry I in order to
provide a favourable habitat for the egrets and screen the area from human
activity.
Feature Paving
11.11.18
The paving will be an important
element of the open space both in aesthetic terms and in terms of producing a
hard wearing landscape. As has been described above the design of the proposed paving
would highlight entrance areas and major pedestrian routes through the site
providing a hierarchy for pedestrian movement. It would be constructed of
quality materials in feature patterns creating a distinct identity to each of
the proposed spaces identified on the LMP. Colour changes within the patterns
would be used to establish themes across the development. Where possible, the
surfaces of internal EVAs will be continuous with the patterns in order to
reduce their intrusion and their delineation should be through the use of
trees, bollards and kerbs rather than by use of a vehicular surface such as
concrete.
Lighting
11.11.19
The lighting design concept for
the landscaped areas should be designed to contribute to the quality of the
development within internal nocturnal views with the highlighting of focal
points and key landscape elements. In general the residential development
landscape will not require 24 hour lighting except for the lighting of access
roads and emergency access. The
intensity, luminance and lighting level generated from residential properties
is predicted to be relatively low in the views available from outside the
development. Glare control measures should be considered for the aesthetic
design of architectural and road lighting within the development to minimise
the visual impact caused by light spillage and glare in views for identified
VSRs. Light fittings and post should be of an attractive design suitable to the
existing rural setting.
Street Furniture
11.11.20
The landscape design would include
the provision of street furniture including seating, which in addition to its
functional attributes would also contribute to the perceived quality of the
landscape.
Children’s Play Area
11.11.21
Facilities such as shaded
seating areas would be provided in the playground. Play equipment should
conform to approved safety standards and include safety surfaces. Children’s play areas would be provided for
easy access and have shaded seating areas for adult supervision.
11.12.1 The landscape works will closely follow the completion of the
construction of the proposed development platform and the proposed built
structures as is shown in Table
11‑10 below. The design year is for the purposes of this study taken as
approximately 10 – 15 years after the scheme opening when the proposed soft
landscape mitigation is mature.
Table 11‑10 Provisional Programme for
Landscape Works
|
Construction
Activities
|
Approximate
Time Scale
|
|
Completion
of the General Construction Works
|
Implementation
of Landscape Works
|
Design
Year
|
|
Improvements works to the Southern
Development Access
|
|
|
2025
|
|
Construction Works of the Development
Area
|
|
|
2025
|
|
Establishment of the Wetland
Nature Reserve
|
|
|
2021
|
11.12.2 For the purposes of this report the above programme has been
simplified to give an indication of the proposed design year for the soft
landscape mitigation measures. At this stage the programme is preliminary and
subject to finalisation during the detail design stages of the project. The
landscape works will be implemented at the earliest possible time in the
planting season immediately following the sectional completion of the
construction works. The implementation schedule of landscape works common to
both options 1A and
1B are presented in Table 10-11 and in the EM&A Manual.
Table 11‑11 Landscape and Visual Mitigation Measures
Implementation Schedules
|
EIA
Ref.
|
Mit.
Code
|
Recommended
Mitigation Measures
|
Location
|
Funding
|
Implementation/
Maintenance Agent
|
Relevant
Standard or Requirement
|
Implementation
Stages
|
Timing
of Implementation
|
Objectives
of the Recommended Measure and Main Concern to address
|
|
D
|
C
|
O
|
|
Construction Phase Landscape and Visual
Mitigation Measures
|
|
11.11
Table
11-8
|
CP1
|
Preservation of Existing Vegetation
|
|
|
|
|
|
|
|
|
|
|
|
CP1.1
|
To retain trees that have high amenity or
ecology value and contribute most to the landscape and visual amenity of the
site and its immediate environs.
|
Site
|
Project
Proponent
|
Project Landscape Architect / Contractor
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
ü
|
|
|
Throughout design phase
|
To minimise the disturbance to the
existing landscape resources.
|
|
|
CP1.2
|
Creation of precautionary area around
trees to be retained equal to half of the trees canopy diameter.
Precautionary area to be fenced.
|
Site
|
Project
Proponent
|
Contractor
/ Contractor
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
|
ü
|
|
Before
construction phase
commence
|
To ensure the success of the tree
preservation proposals.
|
|
|
CP1.3
|
Prohibition of the storage of materials
including fuel, the movement of construction vehicles, and the refuelling and
washing of equipment including concrete mixers within the precautionary area.
|
Site
|
Project
Proponent
|
Contractor
/ Contractor
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
|
ü
|
|
Throughout construction phase
|
To ensure the success of the tree
preservation proposals.
|
|
|
CP1.4
|
Phased
segmental root pruning for trees to be retained and transplanted over a
suitable period (determined by species and size) prior to lifting or site
formation works which affect the existing rootball of trees identified for
retention. The extent of the pruning will be based on the size and the
species of the tree in each case.
|
Site
|
Project
Proponent
|
Contractor
/ Contractor
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
|
ü
|
|
Throughout construction phase
|
To ensure the success of the tree
preservation proposals.
|
|
|
CP1.5
|
Pruning of the branches of existing trees
identified for transplantation and retention to be based on the principle of
crown thinning maintaining their form and amenity value.
|
Site
|
Project
Proponent
|
Contractor
/ Contractor
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
|
ü
|
|
Throughout
construction phase
|
To ensure the success of the tree
preservation proposals.
|
|
|
CP1.6
|
The watering of existing vegetation
particularly during periods of excavation when the water table beneath the
existing vegetation is lowered.
|
Site
|
Project
Proponent
|
Contractor
/ Contractor
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
|
ü
|
|
Throughout
construction phase
|
To ensure the success of the tree
preservation proposals.
|
|
|
CP1.7
|
The rectification and repair of damaged
vegetation following the construction phase to it’s original condition prior
to the commencement of the works or replacement using specimens of the same
species, size and form where appropriate to the design intention of the area
affected
|
Site
|
Project
Proponent
|
Contractor
/ Contractor
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
|
ü
|
|
Throughout
construction phase
|
To ensure the success of the tree
preservation proposals.
|
|
|
CP1.8
|
All works affecting the trees identified
for retention and transplantation will be carefully monitored. This includes the key stages in the
preparation of the trees, the implementation of protection measures and
health monitoring through out the construction period
|
Site
|
Project
Proponent
|
Contractor
/ Contractor
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
|
ü
|
|
Throughout
construction phase
|
To ensure the success of the tree
preservation proposals.
|
|
|
CP1.9
|
Detailed landscape and tree preservation
proposals will be submitted to the relevant government departments for
approval under the lease conditions and in accordance with ETWB TCW No.
2/2004 and WBTC No. 14/2002.
|
Site
|
Project
Proponent
|
Project
Landscape Architect / NA
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
ü
|
|
|
Throughout design phase
|
To ensure the tree preservation and
planting proposals are integrated with the existing landscape context and
that the landscape resources are preserved where appropriate.
|
|
|
CP2.0
|
The tree preservation works should be
implemented by approved Landscape Contractors and inspected and approved on
site by a qualified Landscape Architect. A tree protection specification
would be included within the contract documents.
|
Site
|
Project
Proponent
|
Project
Proponent / NA
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
ü
|
ü
|
|
Throughout
design and construction phases
|
To ensure the tree preservation and
planting proposals are integrated with the existing landscape context and
that the landscape resources are preserved where appropriate.
|
|
11.11
Table
11-8
|
CP2
|
Preservation of Existing Topsoil
|
|
|
|
|
|
|
|
|
|
|
|
CP2.1
|
Topsoil disturbed during the construction
phase should be tested using a standard soil testing methodology and where it
is found to be worthy of retention stored for re-use..
|
Site
|
Project
Proponent
|
Contractor
/ Contractor
|
TM-EIA
Annex 18
|
|
ü
|
|
Throughout construction phase
|
To provide a viable growing medium suited
to the existing conditions and reduce the need for the importation of top
soil.
|
|
|
CP2.2
|
The soil will be stockpiled to a maximum
height of 2m and
will be either temporarily vegetated with hydroseeded grass during
construction or covered with a waterproof covering to prevent erosion.
|
Site
|
Project
Proponent
|
Contractor
/ Contractor
|
TM-EIA
Annex 18
|
|
ü
|
|
Throughout construction phase
|
To provide a viable growing medium suited
to the existing conditions and reduce the need for the importation of top
soil.
|
|
|
CP2.3
|
The stockpile should be turned over on a
regular basis to avoid acidification and the degradation of the organic
material, and reused after completion. Alternatively, if this is not
practicable, it should be considered for use elsewhere, including other
projects.
|
Site
|
Project
Proponent
|
Contractor
/ Contractor
|
TM-EIA
Annex 18
|
|
ü
|
|
Throughout construction phase
|
To provide a viable growing medium suited
to the existing conditions and reduce the need for the importation of top
soil.
|
|
11.11
Table
11-8
|
CP3
|
Development Site and Temporary Works
Areas
|
|
|
|
|
|
|
|
|
|
|
|
CP3.1
|
Where appropriate to the final design the
landscape of these works areas should be restored following the completion of
the construction phase.
|
Site
|
Project
Proponent
|
Contractor
/ Contractor
|
TM-EIA
Annex
18
|
|
ü
|
|
Through
out construction phase
|
To minimise the disturbance to existing
landscape resources and change of visual amenity.
|
|
|
CP3.2
|
Construction site controls should be
enforced including the storage of materials, the location and appearance of
site accommodation and the careful design of site lighting to prevent light
spillage.
|
Site
|
Project
Proponent
|
Contractor
/ Contractor
|
TM-EIA
Annex
18
|
|
ü
|
|
Through
out construction phase
|
To minimise the disturbance to existing
landscape resources and change of visual amenity.
|
|
|
CP3.3
|
Screen the works area during the
construction phase through the use of decorative hoarding along the site
boundary facing adjacent VSRs
|
Site
|
Project
Proponent
|
Contractor
/ Contractor
|
TM-EIA
Annex
18
|
|
ü
|
|
Through out construction phase
|
To minimise the disturbance to existing
landscape resources and change of visual amenity.
|
|
11.11
Table
11-8
|
CP4
|
Mitigation Planting
|
|
|
|
|
|
|
|
|
|
|
|
CP4.1
|
Replanting of disturbed vegetation should
be undertaken at the earliest possible stage of the construction phase
|
Site
|
Project
Proponent
|
Contractor / Contractor
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
|
ü
|
|
After the site formation and on
completion of planting area.
|
To minimise the disturbance to existing
landscape resources and minimize the impacts on the visual amenity of the
area.
|
|
|
CP4.2
|
Use of native plant species predominantly
in the planting design for the buffer areas.
|
Site
|
Project
Proponent
|
Project Landscape Architect/ NA
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
ü
|
ü
|
|
After the site formation and on
completion of planting area.
|
To enhance the local landscape and
ecological value.
|
|
|
CP4.3
|
The tree planting works should be
implemented by approved Landscape Contractors and inspected and approved on
site by a qualified Landscape Architect. A tree planting specification would
be included within the contract documents.
|
Site
|
Project
Proponent
|
Project
Proponent / NA
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
ü
|
ü
|
|
Throughout design and construction phases
|
To ensure the tree preservation and
planting proposals are integrated with the existing landscape context and
that valuable landscape resources are preserved where appropriate to the
final design.
|
|
|
CP4.4
|
All
imported plants should be quarantined in local nursery for minimum 1 month.
|
Local
Green Nursery
|
Project
Proponent
|
Contractor
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
|
ü
|
|
Throughout construction phases
|
To check there are no symptoms of
infection by pests or diseases prior to planting on site.
|
|
11.11
Table
11-8
|
CP5
|
Transplantation
of Existing Trees
|
|
|
|
|
|
|
|
|
|
|
|
CP5.1
|
The tree transplanting works should be
implemented by approved Landscape Contractors and inspected and approved on
site by a qualified Landscape Architect. A tree protection / transplanting
specification would be included within the contract documents.
|
Site
|
Project
Proponent
|
Project
Proponent / NA
|
TM-EIA
Annex 18, ETWB TCW No. 2/2004 & WBTC
No. 14/2002
|
ü
|
ü
|
|
Throughout design and construction phases
|
To
ensure the tree preservation and planting proposals are integrated with the
existing landscape context and that valuable landscape resources are
preserved where appropriate to the final design.
|
|
Operational
Phase Landscape and Visual Mitigation Measures
|
|
11.11
Table
11-9
|
OP1
|
Design of Built Development
|
|
|
|
|
|
|
|
|
|
|
|
OP1.1
|
Adopt
a non-linear building orientation and a stepped building height principle.
|
Site
|
Project
Proponent
|
Project
Architects / NA
|
TM-EIA
Annex 18 and BD
|
ü
|
|
|
Throughout
design phase
|
To ensure the proposals are integrated
with the existing landscape and visual context, and avoid walling effect.
|
|
|
OP1.2
|
Use of a layout and slightly higher
building blocks to allow the incorporation of significant view corridors.
|
Site
|
Project
Proponent
|
Project
Architects / NA
|
TM-EIA
Annex 18 and BD
|
ü
|
|
|
Throughout
design phase
|
Create visual access through the
development to the green backdrop formed by the wooded hillsides to the
south. These view corridors also allow the development to avoid the walling
effect evident in the existing developments to the south and west particularly
when viewed from locations such as the development in the northern part of
Tin Shui Wai. The proposed view corridors are also important from an
ecological perspective.
|
|
|
OP1.3
|
Use of colour blocking utilising range of
visually recessive earth colours and tones on the building facades of the
different blocks. Non-reflective finishes are recommended on the outward
facing building facades. Utilisation
of planting on building façade and balcony to soften the architectural form
of the building.
|
Site
|
Project
Proponent
|
Project
Architects for design / contractor for implementation / Property Management
Agent for maintenence
|
TM-EIA
Annex 18 and BD
|
ü
|
|
|
Throughout
design phase
|
Responsive building façade treatment to
reduce the apparent visual mass of the development and reduce the glare
effect from the reflection of sunlight.
|
|
|
OP1.4
|
Utilise underground car parking and
utilities so as to maximise the area of landscaping.
|
Site
|
Project
Proponent
|
Project
Architects / Property Management Agent
|
TM-EIA
Annex 18, HKPSG and BD
|
ü
|
|
|
Throughout
design phase
|
To maximise the area available for
landscaping and minimise potential impacts of extensive hard surfaced areas
in elevated views both within and without the development site.
|
|
|
OP1.5
|
Use of responsive aesthetic design of
architectural and road lighting with glare containment design measures.
|
Site
|
Project
Proponent
|
Project
Architects / NA
|
TM-EIA
Annex 18, HKPSG and BD
|
ü
|
|
|
Throughout design phase
|
To reduce the night-time glare effect to
the surrounding environs.
|
|
|
OP1.6
|
Formulate lighting operation management
programme to minimise potential light spillage and glare impacts.
|
Site
|
Project
Proponent
|
Property
Management Agent/ Property Management Agent
|
TM-EIA
Annex 18
|
|
|
ü
|
Throughout operation phase
|
To reduce the night-time glare effect to
the surrounding environs.
|
|
11.11
Table
11-9
|
OP2
|
Landscape Buffer Planting
|
|
|
|
|
|
|
|
|
|
|
|
OP2.1
|
Create a landscape buffer area extending around the periphery of the
development to the proposed marsh habitat in WNR providing screening of the
development at low levels and creating a transitional structure, not less
than 50m wide, between the
low-lying fishponds of the WNR and the upright forms of the proposed built
development.
|
Site
|
Project Proponent
|
Contractor / Property Management Agent
for the area within the 4ha
development footprint and a contractor for the area within the WNR
|
TM-EIA
Annex 18, HKPSG and BD
|
ü
|
|
|
Throughout design phase
|
This
planting in addition to the proposed bamboo planting proposed as part of the
ecological mitigation measures will also serve to visually integrate the
proposals within the existing landscape framework.
|
|
|
OP2.2
|
Utilise native tree species in the
planting mix for the landscape buffer area.
|
Site
|
Project Proponent
|
Contractor / Property Management Agent
for the area within the 4ha
development footprint and a contractor for the area within the WNR
|
TM-EIA
Annex 18, HKPSG and BD
|
ü
|
|
|
Throughout design phase
|
Provide a linkage with the existing
wooded areas creating a more coherent landscape framework whilst also
improving the ecological connectivity between existing and proposed woodland
habitats.
|
|
|
OP2.3
|
Formulate a woodland management programme
for implementation during the operational phase.
|
Site
|
Project
Proponent
|
Project Landscape Architect / Property
Management Agent for the area within the 4ha
development footprint and a contractor for the area within the WNR
|
TM-EIA
Annex 18, HKPSG & BD
|
ü
|
|
|
Throughout
design phase
|
Conserve and enhance the ecological
interest.
|
|
11.11
Table
11-9
|
OP3
|
Landscape Strategy for the Design of Amenity
Space
|
|
|
|
|
|
|
|
|
|
|
|
OP3.1
|
The concept should provide a synthesis
between a contemporary design philosophy and sustainable development
principles. The spatial hierarchy involves movement from the public areas to
more intimate spaces. Each of these spaces will be imbued with an individual
character through the use of for example distinctive paving and street
furniture, and plant combinations. The
layout of the space and interconnected footpaths is designed to be legible
with visual access between nodes and distinct entrance courtyards to the
individual development blocks.
|
Site
|
Project
Proponent
|
Project Landscape Architect / Property
Management Agent
|
TM-EIA
Annex 18, HKPSG and BD
|
ü
|
|
|
Throughout design phase
|
Serve to visually integrate the proposals
into the existing landscape framework and provide visual amenity for the
enjoyment of the future residents.
|
|
|
OP3.2
|
The buffer planting is provided along the
edge of the residential development extending to the north in association
with the marsh habitat created under the WNR.
|
Site
|
Project
Proponent
|
Project Landscape Architect / Property
Management Agent for the area within the 4ha
development footprint and a contractor for the area within the WNR
|
TM-EIA
Annex 18, HKPSG and BD
|
ü
|
|
|
Throughout design phase
|
Landscape
buffer designed to create a transitional zone between the general landscape
of the development and the ecological important landscape beyond. This buffer
will also screen low level views of the proposed development.
|
|
11.11
Table
11-9
|
OP4
|
Compensatory
Planting Proposals
|
|
|
|
|
|
|
|
|
|
|
|
OP4.1
|
Utilise
ornamental species within the residential development area whilst species
native to Hong Kong will be utilized within
the buffer planting areas.
|
Site
|
Project
Proponent
|
Project Landscape Architect / Property Management Agent for the area
within the 4ha
development footprint and a contractor for the area within the WNR
|
TM-EIA
Annex
18, HKPSG and BD
|
ü
|
|
|
Throughout
design phase
|
The
planting proposal seeks to compensate for the predicted tree loss resulting
from the construction of the development, visually integrate the proposals
within its existing landscape framework and provide an improved visual
amenity for future residents.
|
|
|
OP4.2
|
A
qualified or registered landscape architect will be involved in the design,
construction supervision and monitoring, and maintenance period to oversee
the implementation of the recommended landscape and visual mitigation
measures including the tree preservation and landscape works on site.
|
Site
|
Project
Proponent
|
Project
Proponent / NA
|
TM-EIA
Annex
18, HKPSG and BD
|
ü
|
|
|
Throughout
design phase
|
The
planting proposal seeks to compensate for the predicted tree loss resulting
from the construction of the development, visually integrate the proposals
within its existing landscape framework and provide an improved visual
amenity for future residents.
|
|
11.11
Table
11-9
|
OP5
|
Southern
Development Access
|
|
|
|
|
|
|
|
|
|
|
|
OP5.1
|
Adopt
a responsive streetscape design with new street tree planting.
|
Site
|
Project
Proponent
|
Project
Landscape Architect / LCSD and HyD for public portion of the road and
Property Management Agent for private areas.
|
TM-EIA
Annex
18, HKPSG and BD
|
ü
|
|
|
Throughout
design phase
|
The
design seeks to visually integrate the road proposals within the landscape of
the existing village setting of Shing Uk Tsuen and Ng Uk Tsuen.
|
Legend: D – Design, C – Construction, O - Operation
Note: BD–
Building Ordinance
ETWB TCW – Environmental
and Transport Works Bureau Technical Circular
HKPSG – Hong Kong Planning
Standards and Guidelines
TM-EIA – Technical
Memorandum on Environmental Impact Assessment Process
TPO – Town Planning
Ordinance
WBTC - Works Bureau
Technical Circulars
11.13.1 Overall, in terms of residual landscape and visual impacts for both
Options 1A and 1B the main
effects will primarily result from the interruption in the relationship between
the fishponds and the uplands which surround them. However the proposed
development in both options will occupy a small part of the overall fishpond
area and cause a low-level of disturbance in terms of the visual amenity
available to VSRs. The landscape character of the fishponds to the east of Tin
Shui Wai will be largely unchanged by the development proposals. The mitigation
measures have been developed to alleviate, where possible, the identified
landscape and visual impacts, and to enhance the future landscape character of
the Study Area.
11.13.2 A series of computer generated images or photomontages have been
prepared for the proposed schemes for Options 1A and 1B and are presented as Figure 11‑14 A to P and 11-15A
to P. The location of the vantage points used for these images has been
identified on Figure 11-6 and 11-10A
and 11-10B. The photomontages of the proposed scheme for both options show the
existing conditions, after the completion of the construction phase when the
primary mitigation measures have been implemented, and Year 1 and Year 10 of
the Operational Phase with the implementation of the secondary mitigation measures.
The final image Operation Phase is designed to demonstrate the predicted
residual impacts, which would exist in the design year during the operational
phase usually taken as between 10 and 15 years after the completion of the
construction phase.
11.13.3 During the preparation of the photomontages the baseline photographs
of the existing situation were taken with a 50mm lens (representing the actual situation as
closely as possible) as a series of photographs. These photographs were
stitched together to form a panoramic view utilising the central portion
(approximately 50%) of each photograph (this is the area with the least
distortion). These photographs were used to demonstrate the existing view.
Vantage Point A (View North
from the Lookout Point at Tsim Bei Tsui (VSR 2))
11.13.4 The photomontage for Option 1A
presented as Figure 11-14A
and B shows the proposed scheme from an elevated viewing position above the
estuarine plain to the north at a distance of 2300m. The image shows the comparatively small scale
of the proposed development in relation to the existing panoramic view whilst
also demonstrating the impact of visually detracting elements such as the
existing Yuen Long Sewage Treatment Plant. The proposed development will also
be seen in the context of the visually more massive high-rise development
associated with Tin Shui Wai and the framed views of the low-rise industrial
estate and high and medium-rise development on the northern periphery of Yuen
Long. Although Kai
Shan Range
will be partially screened by the proposed residential development, the Kai Shan
Range is set within a
developed context with the Yuen Long Sewage Treatment Plant, and Yuen Long and
Tin Shui Wai new town. The use of a responsive building orientation, the
creation of voids within each block containing sky gardens and stepped building
design suggested as part of the landscape mitigation measures will maximise the
visual access to the range. This combined with the full establishment of the
WNR and buffer planting will result in relatively small visual changes for
these VSRs. Furthermore there are
relatively few VSRs at this location, many are transient in nature and
alternate views are available way from the development area. Hence, a moderate adverse residual visual
impact is predicted from this vantage point.
11.13.5 The photomontage for Option 1B presented as Figure 11-15A and B is similar to the view for
Option 1A sharing many of the
same characteristics. In this view the proposed height difference of three
storeys is only apparent in the flatness of the combined roofline of the
residential blocks and in the slightly greater visibility of the bottom of the
hill to the west of the development site and of the high and medium-rise
development of Yuen Long to the south of the development site. This is due to
the elevated viewing position and the distance to the proposed development. In
addition the view corridors which punctuate the development façade for Option 1B appear to be narrower than
those within Option 1B. A moderate adverse residual visual impact is predicted
from this vantage point.
Vantage Point B
(View from the Existing Fishponds to the North of the Development Site (Vantage Point B))
11.13.6 The photomontage presented as Figures 11-14C and D shows the proposed Option 1A scheme from a viewing position from
the estuarine plain at a distance of approximately 900m. Although not an identified VSR this view
demonstrates the developments fit into its landscape context. The view also demonstrates the affectivity of
the proposed landscape mitigation, including responsive building orientation,
sky gardens and stepped building height principles, combined with retained
landscape resources. These mitigation measures maximise the visual access to
Kai Kung Leng with minimised disturbance to the fishponds resulting from the site formation. It shows the relationship
between the built form and the green backdrop to the south of the development
site with the maintenance of the existing ridgeline; the incorporation of the
stepped building height principle to create a more organic building profile
responding to the form of the existing hillside; the use of view corridors to
create a permeable development and allow visual access to the green backdrop;
and the use of colour blocking to break up the visual mass of the development
facades. The development therefore fits into Yuen Long urban and industrial; and Tin Shui Wai high-rise development
landscape context on its east and west.
11.13.7 The photomontage for Option 1B (Figures 11-15C and D) is similar to the view for Option 1A sharing many of the same
characteristics however in this view the slightly reduced building height
allows a slightly greater degree of visibility to the hillside beyond. Again
this is balanced to an extent by the reduced visual access to the hill slope due
to the more narrow view corridors incorporated into the design for Option 1B compared to Option 1A.
Vantage Point C
(View Southeast from the Hong
Kong Wetland Park Entry Forecourt (VSR 13))
11.13.8 The photomontage presented as Figures 11-14E and F shows the
proposed Option 1A
scheme from a public accessible viewing position at the entry forecourt to the
Hong Kong Wetland Park to the north west of the proposed development at a
distance of approximately 1300m.
The image shows the uppermost portion of the proposed development in the
central portion of the picture, and demonstrates the comparatively small scale
of the proposed high-rise blocks within the overall view and the effect of
viewing distance. It also demonstrates the ability of comparatively small
objects, such as the boundary fence and vegetation in the foreground, in
screening long distance views of the proposed development and therefore in
mitigating the potential impacts. Although the proposed development will
partially screen the Kai
Shan Range
it is not a major component within this visual context compared to Tin Shui Wai
high-rise development in the foreground. Therefore a moderate adverse residual
visual impact is predicted from this vantage point.
11.13.9 The photomontage for Option
1B (Figures 11-15E and F) is similar to the view for Option 1A although the proposed development is
slightly less visible due to the proposed reduced building height of 15
storeys. Despite this reduced visibility the Option 1B proposals would also
result in a moderate adverse residual visual impact from this vantage
point.
Vantage Point D (View East from
the Vianni Cove at Tin Shui Wan North (VSR 14))
11.13.10
The photomontage on Figures 11-14G and H shows the proposed Option 1A scheme from an elevated viewing
position some 1200m
to the west of the development site. The image demonstrates that the scheme
proposals form a small component of the overall view available to residents in
relation to the existing panoramic view of coastal plain, stretching to
developments such as Fairview Park in the middle ground and the uplands forming the
Lam Tsuen Country
Park and Kai Kung Leng in
the background. The proposed development will be partially seen in the context
of the high and medium-rise of Yuen Long and the low -rise associated with Yuen
Long Industrial Estate.
The view also demonstrates the visibility of the green backdrop above the
proposed blocks, the permeable development façade formed through the
disposition and orientation of the proposed blocks, and the proposed sky gardens,
and the preservation of views to Kai Shan to the west of the development site.
This view also demonstrates that from a visual perspective the proposed
development occupies a relatively small part of the fish pond area. Although
the visual access to Kai Shan looking from these views will be partially
screened by the proposed development, the implementation of responsive building
orientation and stepped building design will maximise visual access to Kai Shan
and serves to create a more subtle transition between the edge of the proposed
development and its landscape context. This change of visual context will not
be permanent as their view looking east will be interrupted although not
screened after the completion of CDA development at Area 115 in the foreground. The implementation of the CDA
proposals will change the character of views which overlook it to a more urban
character and the presence of this development in the foreground of views will
change the perception of the nature of the future views for residents of lower
floors of this development. The impact of the CDA proposals will be less
pronounced for residents of the upper floors. Given the above the proposals
would lead to a moderate adverse residual visual impact and negligible impact
after the completion of Area 115 development from this vantage point.
11.13.11
The photomontage for Option 1B (Figures 11-15G and H) is similar to the view for
Option 1A although the proposed
development is characterised by its flat roofline which although allowing
greater visual access to the wooded hill side beyond it may be argued that the
flat roofline is visually more incongruous relative to the more organic forms
of the surrounding landscape and therefore more visible. The proposed
development would also give rise to a moderate adverse residual visual impact.
Again the completion of the Area 115 development would change the nature of the
existing views with a more urban character from this vantage point. The reason
for this level of impact is that the construction of the CDA proposals will
change the character of the views to a more urban feeling for VSRs on the lower
floors although this effect will be less pronounced for residents of the upper
floors.
Vantage Point E (View
Northeast from the Kenswood Court
at Tin Shui Wan West (VSR 11))
11.13.12 The photomontage presented as
Figures 11-14 I and J shows the proposed Option 1A scheme from an elevated viewing position to the
northwest of the development site at a distance of some 1000m. Again the view demonstrates that the proposals
would form a small component of future views in relation to the existing
panoramic view of Kai Keng Leng within the Lam
Tsuen Country
Park in the background and Kai Shan
Range in the middle
ground, and the short eastern development façade. The proposed development will
be seen in the context of the development associated with visually Yuen Long
Industrial Estate. Although the proposals form a small component of the view
there will be some partial screening of the knoll adjacent to Ng Uk Tsuen. However potential
adverse impacts will be alleviated through the use of a responsive building
orientation and stepped building design, the creation of a view corridor and
development profile responding to the existing landform. Therefore the view may
be considered to be visually integrated with its immediate context in views
from this location. The development will lead to a moderate adverse residual
visual impact from this vantage point.
11.13.13
Again the photomontage for
Option 1B (Figures 11-15I and J) shares many of the characteristics of the view
for Option 1A. In
both options the viewing angle directs the view towards the narrow western
development façade reducing the visual prominence of the proposed development.
However this same viewing angle also negates the effectiveness of the proposed
view corridors in breaking up the visual mass of the development. In both
photomontages the disruption to views of the wooded hill sides of the Kai Shan
range has been minimised. The development will lead to a moderate adverse residual
visual impact from this vantage point.
Vantage Point F (View North
from Fuk Shun Street
Road Junction near the Site Entrance (VSR 7))
11.13.14 The photomontage presented as Figures 11-14 K and L shows the
proposed scheme from a location adjacent to the site entrance at the pedestrian
level 130m to the south of
the development site. The image
demonstrates the effect of the existing landscape features including the
village houses and open storage uses at Shing Uk Tsuen and existing roadside
trees in partially screening views of the proposed development. From this
location the edge of the village and its associated tree planting forms the
limit to many of the existing views from within the settlement. Further it is
only village houses on the northern edge of the settlement and those near open
spaces which will have glimpsed views of the proposed development and these
views will be limited to the upper floors of the proposed buildings. Beyond
these areas a combination of the proximity of nearby houses and their
orientation serve to screen views north. The use of measures such as the
responsive building orientation, stepped building design and integration of
vertical greening on the building facades serve to further mitigate any
potential impacts. The potential impacts
will be further alleviated through the full establishment of the proposed
buffer planting at the edge of the development and the visual context will be
enhanced through the creation of WNR. Given the above the proposals would lead
to a significant to moderate adverse residual visual impact from this vantage
point.
11.13.15
The photomontage for Option 1B
(Figures 11-15K and L) demonstrates the affectivity of the proposed lower
building height in reducing the visual prominence of the proposed development
in views from the north of the village. Although this is balanced to extent by
the increased width of the view corridors in Option 1A which results in a more visually permeable
development. Given the above the proposals would lead to a significant to
moderate adverse residual visual impact from this vantage point.
Vantage Point G
(View North from Vienna
Villa at Fuk Shun Street (VSR 7)
11.13.16
The photomontage presented as Figures 11-14 M and N shows the proposed scheme
from a viewing position some 250m
to the south of the development site from the car parking are adjacent to the
Vienna Villa development. The image demonstrates the combined effect of the
proposed view corridors and stepped building height concept and the existing
features in mitigating the predicted impact of the development. As discussed in
the description for Vantage Point F above the development will be viewed within
the context of the existing village house on the edge of the settlement and its
potential impact will be alleviated to an extent through the introduction of
mitigation measures. VSRs at this location will have glimpsed views of the
elevated floors of the proposed development. In low level views from this
location the proposed development will be no more prominent than the adjacent village
houses. Given this combination of factors the proposals would lead to a slight
to moderate adverse residual visual impact from this vantage point.
11.13.17
The photomontage for Option 1B (Figures 11-15M and N) demonstrates the affectivity
of the proposed lower building height in reducing the visual prominence of the
proposed development in views from the central parts of the village. The
reduced height of the blocks for Option 1B and therefore the increased
screening ability of the adjacent village houses and the intervening vegetation
serve to reduce the potential impacts arising from the smaller view
corridors. Although this is balanced to
extent by the increased width of the view corridors in Option 1A which results in a more visually
permeable development. Given the above the proposals would lead to a slight
adverse residual visual impact from this vantage point.
Vantage Point H
(View North from Northern Periphery of Jade Court at Ng Uk Tsuen
(VSR 6)
11.13.18
This photomontage (Figures 11-14 O and P)
shows the proposed scheme from a location at the northern periphery of the Jade Court adjacent
to the Tin Hau Temple
in Ng Uk Tsuen some 285m
south of the proposed development site. It represents the view available to
residents living in the northern portion of the village whom will potentially
have glimpsed views of the upper floors of the proposed development. The areas
from which the view is available are constrained to the north by an existing
wetland area and village houses and Tin
Hau Temple
in the foreground. Therefore VSRs living at Jade Court and worshippers at the Tin Hau
Temple will experience a
small to intermediate change in their views. This image demonstrates that only
elevated floors of the proposed development will be visible from this vantage
point as the lower level view has been screened by the existing vegetation and
village houses. The impacts will be further mitigated through the proposed
orientation and disposition of the blocks and the creation of view corridors
through the development and so a moderate to slight adverse visual impact is
predicted.
11.13.19
The photomontage for Option 1B (Figures 11-15O
and P) again demonstrates the affectivity of the proposed lower building height
in reducing the visual prominence of the proposed development in views from the
north of the village. Given the above the proposals would lead to a slight
adverse residual visual impact from this vantage point.
Landscape Planning and
Development Control Review – Options 1A
and 1B
11.14.1 A review of the future proposals for the Study Area as represented
in the Outline Zoning Plans reveals that the proposed schemes for both Options 1A and 1B will fit into the future
landscape of the Study Area. Further the proposed marsh habitat planned for the
area to the north of the development site will form a continuation of the
existing Hong Kong
Wetland Park
contributing to a more coherent landscape framework. The proposals would
therefore largely be compatible with the planning intention for the area and
the planned landuses in the adjoining areas. However the proposed development
sited within the area zoned “Other Specific Uses (Comprehensive Development and
Wetland Enhancement Area)”, “OU(CDWEA)” in the OZP No. S/YL-LFS/7 of Lau Fau
Shan and Tsim Bei Tsui will require the submission of a Section 16 planning
application.
Existing Trees – Options
1A and 1B
11.14.2 In terms of the loss of existing vegetation 238 (36%) of the
existing trees can be retained in-situ and it is recommended that approximately
399 (60%) are felled out of a total of approximately 665. It is also
recommended that approximately 28 (4%) of the existing trees are transplanted
although this is subject to review during the detailed tree survey. The Master
Landscape Plan demonstrates that some 300 new trees can potentially be
established within the main development area in addition to the 3750 square
metres of mass woodland planting established within the project boundary. This
equates to some 1050 new trees with a compensatory planting ratio of
approximately 2.6:1 (new planting: trees recommended for felling). With the
retention of existing trees, the successful establishment of newly planted
trees and the transplantation of some of the existing trees, the project area
will contain approximately 1316 trees which compares favourably to the felling
proposals particularly given that the relatively low value of the existing
trees.
Construction Phase Landscape Impacts
11.14.3 The main residual impacts predicted for the construction phase of
the both the Option 1A and
1B schemes with the incorporation of mitigation measures are as follows:
Landscape Resources –
Options 1A and 1B
·
The main impacts on the
landscape resources of the area are due to the loss of approximately 4 hectares
of fishponds (LR 8) resulting from the construction of the proposed
development. These will be minimised as far as possible through the containment
of disturbance, enhancement of the remaining wetland areas and proper site
management during construction. The impacts will range from moderate adverse
impact to slight adverse residual impact with the implementation of the
recommended landscape mitigation measures.
·
The loss or modification of the
existing landform (LR 1) due to the proposed creation of the WNR which will
result from the removal of some fishpond bunds and modification of others
resulting in a slight/moderate adverse impact in the absence of mitigation
measures. This impact will be alleviated to a slight adverse residual impact
through responsive siting of the proposed development, creation of WNR and the
fishpond enhancement.
·
The loss or modification of the
existing ditches (LR 10) due to the proposed creation of the WNR resulting in a
slight adverse residual impact.
·
The loss of existing trees
during the construction phase of the project would lead to a moderate adverse
impact on LR 13 Existing Trees.
·
The impact on the other
landscape resources within the Study Area will be largely negligible.
Landscape Character –
Options 1A and 1B
·
The Kai Shan Range (NUA 1) will not be subject to
direct impacts however there will be some indirect impacts due to the proximity
of the development and its effect on the landscape setting of the hills sides
however the impact is assessed as being moderate adverse.
·
The Ng Uk Tsuen Village Cluster
(V1) will not be subject to direct impact however there will be some moderate
adverse indirect impact due to the proximity of the development and
modification of Fuk Shun Street.
Although the potential impact on the character of the villages will be largely
limited to the northern portion of the settlement.
·
The agricultural fields in the
Fung Kai Wai – Ng Tung Uk area (AGR 1) will not be subject to impact due to the
screening effect of the existing vegetation to the east of the fields resulting
in a negligible level of residual impact.
·
The existing fishponds (AGR2)
will be subject to limited direct impacts due to the loss of an area during the
creation of the development platform resulting in a moderate to significant
adverse residual impact.
·
The Hong Kong Wetland Park
(OS1) is remoted from the proposed site and so the residual impacts will be
negligible.
·
The Yuen Long Industrial Estate
(ICA1) has a low sensitivity to change being characterised by large industrial
buildings and is physically remoted from the development site. The Kam Tin and
Shan Pui River Estuaries, and the Tin Shui Wai Drainage Channel (EL 1) are also
remote from the development area and so both areas would not be subject to
impacts resulting in a negligible level of residual impact.
Visual Impacts – Option 1A
·
Views available for the
residents of northern Tin Shui Wai (VSR 1) and visitors to the lookout point at
Tsim Bei Tsui (VSR 2) would be subject to a relatively low level of visual
impact due to a combination of the scale of the development, the expansive nature
of the existing views and the viewing distances involved and so there would be
a moderate adverse residual impact.
·
The residents on the edge of
settlements such as Mong Tseng Wai (VSR 3), and Tai Sang Wai (VSR 5) would have
low level, long distance views of the proposed development site, and so
residual impacts would be slight adverse.. Whereas the impacts for residents of
Fairview Park (VSR 4) would be slight to
moderate adverse due to the viewing angle. Views for all three VSRs would be
partially interrupted by intervening vegetation and built structures.
·
Views for residents of
settlements to the south of the development area including Ng Uk Tsuen (VSR 6)
and Shing Uk Tsuen (VSR 7) would be formed by two groups the first the
residents on the northern periphery of the villages (approximately 10 houses in
each settlement) whom have an open view of the development site and those
within the settlement where adjacent buildings and intervening vegetation serve
to screen or partially screen views of the development proposals. In the first
instance the impacts would be moderate to significant adverse due to the
proximity of the proposed development however even for the residents on the
edge of the village some views are partially screened by the existing vegetation
and structures. For residents within the settlements, users of the public open
spaces and vehicle travellers the views are screened or partially screened by
the adjacent village houses and the existing vegetation. Partial views of the
proposed development are largely limited to areas on the edge of large spaces
such as the view forming the basis of photomontage vantage point G. The VSRs on
the northern periphery of the village would be subject to a moderate to
significant adverse impacts while those within the village (the majority) would
be subject to a moderate to slight adverse impact.
·
Walkers using the trail on Kai
Shan (VSR 8) would be subject to a moderate impact due to the proximity of the
proposed development site although alternative views across the estuarine plain
are available to VSRs in this location.
·
The residents of the Long Ping
Estate (VSR 9) will have framed views of the upper storeys of the proposed
development beyond the Kai Shan ridge line however potential impacts will be alleviated
from moderate to slight adverse impact.
·
Views for the residents of the
Tin Tsz Estate (VSR 10) will be largely screened by the landform of Kai Shan
although there will be glimpsed views of the upper storeys of the proposed
development resulting in a moderate to slight adverse impact for those VSRs
with a view of the proposals.
·
The residents on the eastern
side of the Kenswood Court
(VSR 11) will have open views of the development proposals although the visible
part of the development will be along the smallest building façade. Therefore
the residual impacts will be limited to moderate adverse.
·
The residents on the eastern
side of the Tin Yuet Estate at Tin Shui Wai West (VSR 12) will have long
distance views of the development proposals although the visible part of the
development will again be along the smallest building façade. Therefore the
residual impact will be moderate adverse.
·
Visitors to the Hong Kong Wetland Park
(VSR 13) will have glimpsed views of the upper storeys of the proposed development
with low level views being screened by the existing vegetation within the park
and the intervening pond bunds resulting in a moderate adverse residual impact.
·
The upper level residents on
the eastern side of the Vianni Cove (VSR 14) and the Grandeur Terrace (VSR 15)
at Tin Shui Wai will have an overview to the proposed scheme, however due to
the expansive nature of the existing view and the viewing angle the predicted
impacts will be moderate adverse.
·
Future residents of the CDA
(PVSR A1) on the north eastern periphery of Tin Shui Wai will have low-level
largely screened views of the development proposals. These views will be long
distance with the proposed development forming only a small part of the future
view resulting in a moderate adverse level of impact.
·
Night-time glare impacts
generated by the construction activities are predicted to be slight to
negligible in view available to the identified VSRs and these impacts will be
temporary in nature and largely limited to the working day.
Visual Impacts – Option
1B
·
The potential visual impacts
arising from the implementation of Option 1B would be broadly similar to Option
1A. The main differences
would be apparent in views from the villages to the south of the proposed
development site. Views for residents of settlements to the south of the
development area including Ng Uk Tsuen (VSR 6) and Shing Uk Tsuen (VSR 7) would
be formed by two groups the first the residents on the northern periphery of
the villages (approximately 10 houses in each settlement) whom have an open
view of the development site and those within the settlement where adjacent
buildings and intervening vegetation serve to screen or partially screen views
of the development proposals. Based on these locations the impacts for residents
on the periphery of the village would be significant to moderate adverse due to
the proximity of the proposed development however even for the residents on the
edge of the village some views are partially screened by the existing
vegetation. For residents within the villages
(the majority) would be subject to a moderate to slight adverse impact.
Whilst this is less significant than the predicted impact for Option 1A the upper floors of the proposed
scheme will still be visible from some locations within the villages.
Operational Phase Landscape Impacts
11.14.4
The main residual impacts
predicted for the operational phase with mitigation measures are as follows:
Landscape Resources –
Options 1A and 1B
·
In general the impact on LRs
within the Study Area will be largely negligible. Further many will generally
benefit from by the creation of WNR and fishpond enhancement as these works
would improve the quality of the resource including their ecological
value.
·
The impacts predicted for the
landscape resources of the Study Area during the construction phase will
largely persist into the operational phase of the project with the exception of
the plantation woodland (LR 3) which will be enhanced through the
implementation of the woodland landscape buffer around the development site
(resulting in a moderate to significant beneficial impact). The existing
wetland resource (LR 12) will also significantly benefit by the creation of the
WNR providing extension extending this valuable resource within the local
context. In addition the proposed
created marsh habitat and fish pond enhancement under the WNR proposals will
lead to a qualitative enhancement of the directly affected LRs such as the
Existing Landform (LR1), the Fishponds (LR8), the Watercourses-Ditches and Drainage
Channel (LR10) and improve the local landscape diversity. Given these
enhancements the LR 3 will benefit from the full establishment of the proposed
mitigation measures including the WNR and woodland edge planting around the
development resulting in a moderate beneficial impact.
·
With the proposed planting of
significant number of new trees there would be a moderate beneficial impact on
LR 13 Existing Trees.
Landscape Character –
Options 1A and 1B
11.14.5
The impacts predicted for the
landscape character of the Study Area during the construction phase of the
project for both Options 1A and
1B will largely persist into the operational phase of the project although the
growth to maturity of the tree and shrub planting proposed as part of the marsh
habitat and the landscape buffer planting on the periphery of the development
will serve to encourage greater sense of landscape and visual integration with
the development’s context. This planting will also serve to soften the
transition between the verticality of the proposed built environment and the
surrounding coastal plain. The planting proposals will also alleviate some of
the indirect impacts on the Ng Uk Tsuen Village Cluster (V1) and the Kai Shan
Range (NUA 1) and provide
some benefit to the local character with a slight adverse impact with full
establishment of the proposed mitigation measures. The impact on the landscape
character of the village cluster will be restricted to the northern periphery
of the settlement. Impacts on the character of the existing Fishponds (AGR 2)
will also be partially alleviated through the implementation of the proposed
mitigation measures resulting in a slight adverse impact. The landscaping
associated with the proposed landscape buffer and the establishment of the WNR
would also have a slight beneficial impact on the adjacent areas of the Hong
Kong Wetland Park (OS1).
Visual Impacts – Option 1A
11.14.6
Many of the views for the
identified VSRs share a number of common characteristics which include their
expansive nature, the viewing distance and in many cases an elevated viewing
position resulting in slight to moderate to significant adverse impact at
operational stage in the absence of mitigation measures. In this situation the
proposed primary mitigation measures such as the location of the development
platform and form of the built structure including the adoption of a stepped
building height, sky gardens and view corridors take precedence over the
proposed soft landscape mitigation measures although these measures serve an
important role in further mitigating the predicted adverse impacts. There are however some exceptions with
visitors to the Hong Kong Wetland Park (VSR 13), walkers on Kai Shan footpath
(VSR8), residents on the eastern periphery of Tin Shui Wai such as Tin Tsz
Estate (VSR10), Tin Yuet Estate (VSR12) and Grandeur Terrace (VSR15) and Long
Ping Estate at Yuen Long realising a level of mitigation due to the proposed
landscape buffer planting, the predicted level of residual visual impact for
these VSRs although due to the assessment methodology the impacts will be
maintained at moderate adverse. It should also be noted that for many of these
VSRs the proposals will form a small component of the wide panoramic views of
the coastal plain which is available to them. Whilst with the completion of the
construction phase of the project and the implementation of the proposed
mitigation measures the predicted visual impact experienced by the residents of
Kenswood Court (VSR11), Tin Yuet Estate (VSR12) and Vianni Cove (VSR14) at Tin
Shui Wai will be moderate adverse.
11.14.7
Given that the majority of the
identified VSRs are located at distances of 1000m or more from the proposed development and the
fact that in many views the development will be seen against the backdrop of
the existing street lighting in the adjacent villages and Yuen Long the
predicted night time glare impacts will not be significant. The predicted
impacts for the other VSRs in the construction phase will persist into the
operational phase. The adoption of responsive site planning and lighting design
with glare control measures as described in the previous section would serve to
mitigate much of the potential impacts. In addition the proposed use of a
vegetative landscape buffer and the screening effect of the existing vegetation
will mitigate much of the potential night time impacts for VSRs at low
elevations such as the Hong Kong
Wetland Park.
Overall the night-time glare impact resulting from the proposed architectural
and road lighting would have a predicted slight adverse to negligible impact
for the large part of the existing and planned VSRs.
Visual Impacts – Option
1B
11.14.8
The shared characteristics of
many of the existing views including their expansive nature, the viewing
distance and relative elevation mean that for many VSRs, Options 1A and 1B would appear similar. It may be
argued that despite the Option 1B
adopting a 15 storey maximum height the flat roofline
(contrasting with the organic forms of the adjacent landscape), the
introduction of an additional block and the reduced view corridors ensure that
the proposals have a similar level of visual prominence. Given this the
predicted visual impacts particular for the VSRs to the north, east and west of
the application site are similar to those predicted for Option 1A. The main differences would be
apparent in views from within the villages of Ng Uk Tsuen (VSR 6) and Shing Uk
Tsuen (VSR7). The reduced height of Option 1B would reduce the visibility of
the proposals in views from within the village however in many instances these
views are largely interrupted by existing features such as the adjacent village
houses and the intervening vegetation. In views from the northern periphery of
the village it is considered that the reduced height of Option 1B is balanced
to an extent by the wider view corridors of Option 1A which allow greater albeit framed visual access to
the fishpond area to the north.
11.14.9
Overall the visual impacts
range from moderate adverse to slight adverse for the majority of VSRs due to
the viewing distances involved (typically 1200 to 3000m) and the direction of view, the broad expanse of
the existing views extending east over the coastal plain, and the presence of
existing high-rise development on the northern periphery of Yuen Long and the
eastern edge of Tin Shui Wai. In addition the proposed architectural schemes
for Options 1A and
1B have been designed to respond to the existing landscape and visual context
including measures such as the height and disposition of the proposed blocks,
the use of stepped height profile, the creation of view corridors and the
proposed treatment of the building facades.
Acceptability of Impacts
11.14.10
In
accordance with Annex 10, Paragraph 1.1(c) of the EIAO TM, the landscape and
visual impacts of the project under the proposed
development at Fung Lok Wai for both Options 1A and 1B would be ‘acceptable with mitigation’ that
is to say `there would be some adverse
effects, but these can be eliminated, reduced or offset to an extent by
specific measures’.
12.
Fisheries impact assessment
12.1.1
This assessment has been prepared in accordance with the
requirements of the EIAO and the criteria and guidelines defined in Annex 9
(“Criteria for Evaluating Fisheries Impact”) and Annex 17 (“Guidelines for
Fisheries Impact Assessment”) of the Technical Memorandum on Environmental
Impact Assessment Process respectively. Specifically it includes:
·
A detailed description of the
baseline physical environment;
·
Description and quantification
of the existing pond aquaculture practices and associated resources;
·
Identification of associated
socio and economic issues relating to fish pond management;
·
Identification of potential
direct and indirect impacts to aquaculture practices during the construction
and operation of the development, including the Wetland Nature Reserve;
·
Identification of potential
mitigation measures that could be utilised to reduce or overcome the potential
impacts of the construction and operation of the development, including the
Wetland Nature Reserve; and
·
Review of the need for
monitoring during the construction of the development, including the Wetland
Nature Reserve.
Scope and aims of this Fisheries Impact
Assessment
12.1.2
In accordance with Section 3.5.7.1
of the Study Brief (EPD 2000) the extent of this assessment comprises:
·
Aquaculture resources present
within the “area of the boundary of the proposed development (including the
access road)”; and,
·
“Its adjacent area of potential
impact” which, for the purposes of this assessment is taken to mean any
aquaculture or mariculture resources that may be affected by the construction
or operation of the proposed development.
12.1.3
Figure 12‑1 illustrates the site boundary and extent of the FIA
Assessment Area. For the purposes of this assessment the following areas were
defined:
·
Proposed Development Area – the area
directly affected by residential construction.
·
Wetland Nature Reserve – the area of
fishpond enhancement and marshland creation.
·
Assessment Area – comprising the
Proposed Development Area, the proposed Wetland Nature Reserve, the proposed
Access Road and any adjacent aquaculture, mariculture or marine fisheries
resources that may be affected by the construction or operation of the proposed
development.
12.1.4
The aims of this assessment are
to provide sufficient and relevant information to assist the Environmental
Protection Department (EPD) and the Agriculture, Fisheries and Conservation
Department (AFCD) to:
·
Identify, assess and evaluate
the fisheries resource of the Assessment Area;
·
Identify, assess and evaluate
any adverse impacts that will arise during the construction and operation of
the proposed development, and evaluate the acceptability of these impacts;
·
Identify, assess and evaluate
cumulative impacts within the North
West New Territories; and,
·
Identify, assess and evaluate
the effectiveness of proposed mitigation measures that will be adopted to
minimize or eliminate the predicted impacts that will arise during the
construction and operation of the proposed development.
Specific Objectives of This Assessment
12.1.5
The EIA study brief for this
proposal (EPD, 2000) identifies specific objectives and requirements for the
Fisheries Impact Assessment. These are listed below and the sub-section within
which each is addressed is indicated:
·
Describe the physical
environmental background (Section 12.3);
·
Describe and quantify as far as
possible existing aquaculture activities, with special attention on Fung Lok
Wai and around Mai Po
(Section 12.3);
·
Describe and quantify as far as
possible existing fisheries/aquaculture resources (Section 12.4);
·
Identify parameters (eg Water
Quality Parameters) and area that are important to aquaculture activities
(Section 12.3 and 12.4);
·
Identify and quantify as far as
possible any direct/indirect and on-site/off-site impacts to aquaculture,
including permanent loss and temporary occupation of fishponds and those
impacts on aquaculture activities due to sewer bursting and emergency discharge
from sewage pump house (Section 12.5);
·
Evaluate impacts on aquaculture
activities during construction and operation stages in areas around Fung Lok
Wai and Mai Po
and other affected areas (Section 12.5);
·
Evaluate cumulative impacts of
loss of fishponds in the North
West New Territories (Section 12.5);
·
Identify practical mitigation
measures to avoid/minimise the potential impacts on the aquaculture activities
(Section 12.6);
·
Identify and present an
adequate package of measures to fully compensate all the losses due to the
project with details on justification, description of scope and programme
feasibility as well as staff and financial implications including those related
to subsequent management and maintenance requirements of the proposals. Among
other measures, the need to reinstate affected fishponds and other aquaculture
sites (Section 12.6); and,
·
Determine the need and, if
necessary, make appropriate recommendations for a monitoring and audit
programme (Section 12.7).
12.2.1
A habitat map of the site was
produced in connection with the Ecological Impact Assessment (Figure 13‑9, Section 13.5). In collating this map the boundaries
of existing fishponds were identified within the Assessment Area defined for
this FIA (see above).
12.2.2
Baseline information regarding
fisheries resources and activities within this area were identified on the
basis of:
·
Review of existing published
and unpublished literature, including ecological information collected in
connection with the preparation of the Ecological Impact Assessment;
·
Site inspections;
·
Consultations with AFCD
aquaculture specialists and reference to published government reports; and,
·
Liaison with the Hong Kong New
Territories Fish Culture Association and aqua-culturists.
12.3
Description of the Physical
Environment
12.3.1
This sub-section provides
details of the geographical and physical context of Fung Lok Wai including past
and present land-uses, superficial geology, topography, hydrology and water
quality.
Location and Regional Context
12.3.2
The Assessment Area is located
to the south of Inner Deep Bay in
the North West New Territories
of the Special Administrative Region of Hong Kong. Figure
12‑1 illustrates the location of the proposed development
site and assessment area in the context of the Deep Bay
environs. To the west the site is bounded by mangroves along the tidal creeks
of the Tai River outfall, beyond which are
grasslands, reed beds, a plantation and fishponds. Further to the west of Fung
Lok Wai is Tin Shui Wai New Town. To the northwest there is an area of tidal
lagoons (near Tsim Bei Tsui) created by the construction of a causeway for the
road and border security fence.
12.3.3
The site is bounded to the
north and east by wetland habitats. A continuous band of one or two fishponds
bound the site to the immediate north, beyond which lies a belt of mangroves
which give way to the tidal mudflats and increasingly marine conditions of Inner Deep
Bay. Further to the
northeast, beyond the Shan
Pui River,
there is a large area of fishponds and the Mai Po Nature Reserve, a
complex of mangrove, gei wai, reed bed and fishponds. Fishponds also bound the
site to the east, beyond which is a strip of landscaped land either side of the
closed area boundary road, which demarcates the eastern extent of land
reclamation. Further east is the Main Drainage Channel for Yuen Long, Kam Tin
and Ngau Tam Mei drainage from the Shan
Pui River.
To the southeast lies Yuen Long Sewage Treatment Works to the south of which
lies Yuen Long Industrial Estate. The
south of site is bounded by undeveloped low hills. These are predominantly
covered in semi-natural scrub and woodland vegetation with some grassland and
orchards. Much of the lower lying areas have been developed for residential
housing or cultivated for wet and dry agricultural uses, depending on drainage
conditions. Tin Shui Wai new town lies to the southwest and in the western part
of the site there are large areas currently under construction relating to the
ongoing development of Tin Shui Wai and the operation of Hong Kong Wetland
Park.
Geology and soils
12.3.4
The superficial geology of the
site consists of estuarine deposits of marine and fluvial origin, predominantly
silts and clays. No borehole information
is available from Fung Lok Wai itself, but investigations elsewhere indicate
that lenses of sands and gravels of alluvial origin may occur underneath the
surface estuarine deposits (see Townland et
al. 1992).
12.3.5
The soils of Fung Lok Wai are
derived from mangrove soils and ultimately have their origin as marine sediment
and riverine alluvium. Texturally the soils are dominated by silt and clay
fractions, the relative proportions of which produce soils that vary from clay
through silty clay to silty clay loam (USDA texture classes). Sand content is generally low. Very small
amounts of gravel are present. The soils have been considerably reworked during
reclamation and through management for fish farming.
12.3.6
Soil samples taken in January
1996 were slightly acidic, with a mean pH of 6.8. The soils are poorly drained
and frequently highly saline, rendering them of little agricultural value.
Topography, Hydrology and Watercourses
12.3.7
The site has an open, flat and
low-lying aspect. The major variation in site level is due to the excavation of
the fishponds and creation of bunds. The level on top of the fishpond bunds
varies from approximately +3.1 m
to +3.3 m PD, at the north
and east of the site, to about +4.2 m
PD at the south.
12.3.8
Water for the fishponds comes
from direct rainfall. During winter and
when ponds are drawn down, water is pumped from one pond to another to conserve
resources. After heavy summer rainfall, ponds may fill and drain into adjacent
channels. Channels may also occasionally be used for transferring water, by
pump, between fishponds.
12.3.9
No flow data are currently
available for the drainage channels, however, a site inspection on 10th January
1998 revealed that all channels contained shallow water (c. 10 cm) and that there were low flows
from those draining catchments the adjacent catchments to the south.
12.3.10
The mangrove-lined channel (Tai River
outfall) at the north-western perimeter of the site is intertidal. The perimeter bunds are approximately +3.8
mPD and higher than the predicted mean high water in the channel (+2.4 m PD). Therefore in normal
circumstances the interior of the site remains free of tidal influence.
Overtopping of the perimeter might occur in an extreme combined high tide and
storm event. However, this is likely to be extremely rare given the past
extreme sea levels at nearby Tsim Bei Tsui, which peaked at +3.85 mPD with a
return period of 100 years for records between 1974 and 1990. The predicted
tidal range for 2002 at Tsim Bei Tsui is 0-3 mPD with an average peak tide of
+2.4 mPD.
Water Quality
12.3.11
No data are currently available
on the quality of water in the existing watercourses. However, all the
catchments are dominated by dense semi-natural scrub and woodland vegetation
and there are no apparent point sources of pollutants such as pig farms etc. It
is therefore expected that the water entering the site is likely to be of
relatively low nutrient status and with a low Biological Oxygen Demand (BOD).
It is also anticipated that suspended silt in runoff during heavy rainfall
periods is likely to be relatively low due to the existing dense vegetation
cover in the catchments.
12.3.12
The results of water quality
sampling in the fishponds at Fung Lok Wai undertaken in May 2002 are shown in Table 12‑1. These data suggest that water quality in the ponds
is generally in accordance with AFCD (1995) recommendations for fishponds
although some ponds appear slightly alkaline and BOD is high due to eutrophic
status.
Table 12‑1 Results of Fishpond/ River Water Quality Survey at Fung Lok
Wai
|
|
Sampled
Fishpond
|
River
water Sampling Stations
|
|
Parameters
|
Pond
2
|
Pond
13
|
Pond
19
|
Pond
56
|
Pond
59
|
Pond
62
|
W1
(Shan Pui River)
|
W2
(Tai River)
|
|
pH
|
6.2
|
7.7
|
9.3
|
6.9
|
8.9
|
7.0
|
7.8
|
7.5
|
|
Conductivity (uS/cm)
|
2510
|
1860
|
635
|
1640
|
1100
|
1100
|
16500
|
21500
|
|
D.O. (mg/L)
|
5.4
|
4.4
|
7.2
|
2.6
|
8.2
|
2.4
|
3.1
|
2.1
|
|
% Saturation of D.O. (%)
|
72.5
|
62.2
|
98.1
|
38.5
|
108
|
28.1
|
41.7
|
28.7
|
|
Temp. (oC)
|
31.3
|
31.0
|
30.4
|
30.7
|
32.5
|
30.5
|
30.0
|
29.0
|
|
Salinity (g/L)
|
1.1
|
0.5
|
0.3
|
0.7
|
0.5
|
0.5
|
8.8
|
11.9
|
|
Turbidity (NTU)
|
45.2
|
30.7
|
23.1
|
63.3
|
23.5
|
42.4
|
12.7
|
20.0
|
|
SS (mg/L)
|
72.7
|
57.0
|
28.3
|
93.7
|
47.0
|
49.7
|
32.3
|
26.3
|
|
Ammonia as N (mg/L)
|
0.03
|
0.03
|
0.04
|
2.96
|
0.07
|
0.39
|
5.4
|
2.8
|
|
Nitrate as N (mg/L)
|
<0.01
|
<0.01
|
<0.01
|
0.04
|
0.04
|
0.23
|
0.6
|
0.7
|
|
Nitrite+Nitrate as N (mg/L)
|
0.02
|
0.02
|
0.02
|
0.16
|
0.17
|
0.31
|
0.9
|
1.2
|
|
Total Kjeldahl Nitrogen as N (mg/L)
|
3.2
|
2.9
|
3.9
|
4.6
|
3.3
|
3.6
|
7.3
|
3.1
|
|
Total Nitrogen (mg/L)
|
3.2
|
2.9
|
3.9
|
4.8
|
3.5
|
3.9
|
8.2
|
4.3
|
|
Total Phosphorus (mg/L)
|
0.2
|
0.2
|
0.2
|
0.2
|
0.2
|
0.3
|
0.7
|
0.5
|
|
Reactive Phosphorus as P (mg/L)
|
0.03
|
0.03
|
0.02
|
0.02
|
0.03
|
0.02
|
0.6
|
0.4
|
|
BOD (mg/L)
|
10.0
|
8.7
|
14.3
|
5.3
|
9.0
|
4.7
|
3.0
|
<2
|
Note: All
measurements by ALS Technichem (HK) Pty Ltd. on 30 May 2002. See Figure 12‑1 for location of ponds.
Past and Current Land
Use
12.3.13
Originally the Deep Bay
area was dominated by brackish and freshwater marshland habitats. However, Deep Bay
and its surrounding areas have undergone significant changes over the last
century which have been discussed in a number of studies (Melville &
Morton, 1983; Young, 1991, Aspinwall Clouston and Wetlands International 1997).
12.3.14
Reclamation of marshes and
inter-tidal habitats took place predominantly from the last century until the
middle of this century, with 1,200
ha of land being reclaimed between 1903 and 1945. This land was
converted to agricultural use, mostly cultivation of brackish water rice and
shrimp production in gei wais (tidal shrimp ponds).
12.3.15
Between the mid 1960’s and 80’s brackish and fresh water rice cultivation
disappeared and almost all cultivated land and gei wais were converted to deep
water fishponds. By 1974, this had
become the dominant land use and provided an extensive area of wetland habitat.
However, by the same time, virtually all areas of natural and semi-natural
freshwater habitat had been lost.
12.3.16
From the late 1970’s to the present urban development
has taken over as the main pressure for change in the Deep Bay
area, the main impact being the infilling of fishponds and the use of the land
for housing, industrial estates and open industrial storage. Between 1985 and
1994, for example, the coverage of fishponds dropped from over 2,000 ha to 1,500 ha, representing a 25% decrease over 10 years.
12.3.17
Furthermore, many fishponds
have been abandoned which reduces their ecological value to many important
species, in particular herons and egrets. Of the fishponds remaining in the Deep Bay
area in 1994 only 78% were still actively managed (Everitt and Cook 1997), with
the majority located in the North
West New Territories, mostly in or within the
vicinity of the Mai Po Inner Deep Bay
Ramsar Site.
12.3.18
The Fung Lok Wai site has shown
similar changes in land use as the Deep
Bay area as a whole. In
1924, it is understood that there was a number of large (presumably tidal)
lagoons, within the northern half of the site which is now included within the Mai Po Inner Deep Bay Ramsar Site. Some areas of
mangrove still appear to be present within the lagoons. The southern area of
the site which currently falls outside the Mai Po Inner Deep Bay
Ramsar site boundary but within the boundary of the Wetland Conservation Area
(WCA) includes some mangrove but also small rectangular fields, which were
probably brackish rice paddies.
12.3.19
An aerial photo dated November
1974 shows that most of the site was still tidal at this time; however a number
of fishponds had been established in the south-western portion of the site.
Since then, virtually the whole site has been converted to freshwater ponds,
the majority of which are currently actively used for freshwater fish farming.
12.3.20
The Fish Pond Study (Aspinwall
Clouston & Wetland International, 1997) documented the ecological value and
function that aquaculture ponds have to wildlife, particularly waterbirds. The Fish Pond Study identified that
aquaculture ponds within the Deep Bay were managed, until 1995, following
traditional aquaculture management practices (i.e. annual stocking, draining
and harvesting of the ponds), were of particular ecological value to wetland
birds (e.g. Ardeids, Black-faced Spoonbill) when the ponds were drained at
harvest time. The Fish Pond Study
revealed that water birds feed on small fish (e.g. Tilapia (Oreochromis mossambicus), Mosquito fish
(Gambusia affinis) and Prawns (Macrobrachium nipponense)) that are of
no commercial value and which are bi-product of traditional aquaculture
management practices.
12.3.21
The area of aquaculture ponds under
active management in the Deep
Bay area is now declining
along with productivity (Table
12‑2).
Table 12‑2 Area of Ponds and Inland Fresh Fish Production In Hong Kong. Source AFCD Annual Reports, 2002
|
Year
|
Area
of ponds (ha.)
|
Production
(tonnes)
|
|
1998
|
1370
|
4900
|
|
1999
|
1370
|
4500
|
|
2000
|
1280
|
2820
|
|
2001
|
1250
|
2550
|
12.3.22
Some of the key reasons for
this decline include:
·
Reduction in market price of
fish due to cheaper imports from mainland China;
·
Intensification of some
operations; and,
·
Conversion of ponds to other
uses.
Traditional
aquaculture management practices
12.3.23
The following section
summarises a five stage annual management cycle practiced by most
aquaculturists.
Stage 1: Pond preparation
12.3.24
Drained down ponds are allowed
to dry out. Desiccation and the action of sunlight assist breakdown of organic
detritus and reduce levels of bacteria and other pathogenic organisms.
Traditionally this process allowed take place over the winter months, however,
many operators now continue production throughout the year and in these
circumstances, following harvesting, eutrophic water from nearby ponds will be
transferred to the pond before re-stocking.
12.3.25
When ponds are dried out, a
layer of lime (Calcium oxide) is applied to the base of the pond. The purpose of adding lime is:
·
to neutralise the pH of pond
sediments and buffer acid formation. The marine based soils of the fishponds
are prone to acidification if allowed to dry;
·
to accelerate the decomposition
rate of organic matter that remains at the base of the pond; and
·
to sterilise the ponds of
bacteria and other pathogens.
12.3.26
Some operators apply a layer of
teaseed cake (Saponin) to the base and sides of the pond to kill carnivorous
fish species (e.g. eel, snakehead, catfish) that may burrow into the soft mud
of the pond base and emerge after re-filling to predate juvenile stock.
12.3.27
Organic fertilizer such as
poultry manure, peanut cake, decaying fish, etc is applied to the base of the
pond to initiate prolific growth of phytoplankton and to provide an organic
food supply for zooplankton and aquatic invertebrates, all of which provide a
food resource for juvenile fish.
12.3.28
Once prepared, the pond is
partially refilled with rain water or by pumped transfer from adjacent
ponds. If pumped, precautions, such as
placing nets over inlet pipes, are taken to minimize introduction of predatory
fish. The recommended water quality for initiation of fish culture is summarised
in Table 12‑3
Table 12‑3 Optimum
Water Quality Objectives for Initiating Fish Rearing
|
Variable
|
Parameters
|
|
Ammonia (as nitrogen)
|
<0.1 mg/l
|
|
BOD5
|
<10 mg/l
|
|
Chlorine
|
<0.1 mg/l
|
|
Chlorophyll-a
|
<1 mg/l
|
|
Dissolved oxygen
|
>1 mg/l
|
|
Oxidised nitrogen (as nitrogen)
|
<5mg/l
|
|
PH
|
6-8.5
|
|
Phosphate (as phosphorous)
|
<1 mg/l
|
|
Salinity
|
<2o/oo
|
|
Suspended solids
|
<20mg/l
|
Stage 2: Stocking
12.3.29
Approximately 95% of
aquaculture ponds present within the Deep
Bay are managed following
a polyculture system i.e. several species of fish are reared simultaneously in
the same pond. Polyculture species of
fish are stocked at density of 10,000-35,000 fingerlings per hectare.
12.3.30
A small number of ponds are
managed under monoculture systems involving intensive rearing of single species
such as catfish, seabass and snakehead.
12.3.31
Traditionally ponds were
stocked during the period February to
April, increasingly, however, ponds will be stocked at any
time of the year reflecting a continuous production cycle.
12.3.32
Stock are now acquired from a
variety of domestic and overseas sources including: Mainland China, Taiwan,
Japan and Australia. The size of the stock
purchased varies from fry (newly hatched fish) that are typically under 1cm in size, to juveniles up to 10 or 15cm. Typical species are indicated in Table 12‑4. The size and species of fish sourced depends on
factors such as: personal preference, market availability, price and perceived
demand for adult fish.
12.3.33
Once stocked the pond is
enriched with nutrients (e.g. fine grains of wheat or soya) to promote
phytoplankton growth.
Table 12‑4 Summary Of Fish Species Typical Of Polyculture Practice In The
Deep Bay Area And Examples Of The Sources Of
Stock
|
Species
|
Source of Stock
|
|
Carp (including silver, grass, mud)
|
PRC, Taiwan
|
|
Grey Mullet
|
PRC, Hong Kong SAR, Japan, Taiwan
|
|
Sea Bass
|
USA
|
Stage 3: Rearing
12.3.34
Between February and October
fish grow rapidly and are consequently fed once to twice a day. Traditionally a variety of feed materials
have been used including: biscuit, bread, brewery waste, corn meal, noodles,
peanut cake, wheat bran, rice bran, sorgum, soya bean. Some farmers now use specialised feed
pellets, particularly within those ponds under more intensive rearing regimes.
As fish grow the proportion of protein in the diet is increased.
12.3.35
During the rearing stage fish
behaviour is monitored daily. Evidence
of low oxygen concentrations (e.g. large numbers of fish observed close to the
surface of the pond), excessive feeding (e.g. accumulations of feed at the pond
base) or other problems associated with water quality and disease is corrected
accordingly.
12.3.36
Fish appetites are governed by
a number of factors including growth stage, temperature and dissolved oxygen
concentration. Feed levels are monitored closely to avoid under or over-feeding
and to optimise the nutritional content of feed.
12.3.37
During the summer months
additional organic fertiliser in the form of, for example, pig and poultry
manure or peanut cake, is added to supplement the nutrient status of the ponds
and promote phytoplankton production.
Stage 4: Harvesting
12.3.38
Typically fish are harvested
once they achieve marketable size (Table
12‑5), although farmers will avoid harvesting when prices
are low.
12.3.39
The market value for live fish
harvested from aquaculture ponds in the Deep Bay
area varies considerably. For example
the market value for Grey Mullet during the early 1980s was approximately $25/
cattie, by late 1998 this had declined to as little as $6/cattie in the face of
cheaper mainland imports (Cheung, 1999).
12.3.40
Traditionally harvesting tended
to take place between October to March, although continuous production cycles
are now seeing fish sent to market throughout the year.
12.3.41
In preparation of harvesting
the pond is drained over 2-4 weeks.
Water is pumped into adjacent ponds or watercourses. Periodically a seine net is dragged across
the corner of the pond in an arc shape.
The entrapped fish are removed and placed in tanks before transportation
to market.
Table 12‑5 Production
Time And Acceptable Market Size Of Species Of Fish Raised In Aquaculture Ponds
|
Species
|
Number
of months required to raise fish to market size (months)
|
Acceptable
market size (kg)
|
|
Bighead
|
9-14
|
1.0 - 2.0
|
|
Common Carp
|
6-9
|
0.3 - 0.6
|
|
Grass Carp
|
20 – 24
|
1.0 - 2.5
|
|
Grey Mullet
|
7 – 12
|
0.2 - 0.6
|
|
Silver Carp
|
9 – 14
|
1.0 - 2.0
|
|
Tilapia
|
4 – 9
|
0.2 - 0.6
|
Stage 5: Pond maintenance
12.3.42
Following fish harvesting, the
base and sides of the pond are allowed to dry out to aid removal and
decomposition of accumulated organic material. Discontinuation of the practice
of rearing ducks in association with fishponds has reduced the level of organic
input and reduced the need for annual removal of detritus by bulldozer. Consequently ponds are now only dredged once
every three to five years.
Aquaculture
12.4.1
For the purpose of this report
the rearing of fish in commercial fishponds is referred to as “aquaculture”.
The personnel who undertake the daily management of the ponds are
“aquaculturists”. “Actively managed ponds” refers to aquaculture ponds present
within the Assessment Area” in which fish are actively reared for commercial
purposes. These were identified during a site inspection conducted in January
2001 on the basis of the following criteria:
·
Evidence that the vegetation
growing on adjacent pond bund is managed (i.e. cut back);
·
Commercial fish species
present;
·
Evidence of recently used aquaculture
equipment; or,
·
Presence of fish-rearing
paraphernalia, such as, for example, fish feed and nutrients (e.g. manure).
12.4.2
Ponds that did not meet these
criteria (ie for which there was no evidence of fish being reared for
commercial purposes) were designated “unmanaged ponds”. It should be noted,
however, that the status of ponds can change from time to time.
Status of Aquaculture Management of
Ponds within the Assessment Area
12.4.3
The extent of aquaculture ponds
within the Assessment Area is summarised in Table
12‑6.
12.4.4
The majority of these ponds are
under active management with occasional ponds that appear to have fallen into
disuse. Ponds range in size between from approximately 0.17 to 2.87 ha. with a mean size of
approximately 1.5 ha.
Table 12‑6 Extent
of
Habitats Identified Within the Fung Lok Wai Assessment Area
|
Habitat
|
1. Proposed
Development Area
|
2. Wetland Nature
Reserve
|
3. FIA Assessment
Area (1 + 2)
|
|
Intertidal forested wetlands
|
0
|
0
|
0
|
|
Permanent rivers, streams and creeks
|
0
|
0
|
0
|
|
Ditches and drainage channels
|
0.02
|
0.38
|
0.40
|
|
Aquaculture pond (actively managed)
|
2.56
|
59.88
|
62.44
|
|
Aquaculture pond (unmanaged)
|
0.75
|
7.41
|
8.16
|
|
Pond bunds
|
0.67
|
8.44
|
9.11
|
|
Reedbed
|
0
|
0
|
0
|
|
Permanent freshwater marsh and pools
|
0
|
0
|
0
|
|
Seasonally flooded (wet) agricultural land
|
0
|
0
|
0
|
|
Dry agricultural land
|
0
|
0
|
0
|
|
Inactive agricultural land
|
0
|
0
|
0
|
|
Orchard
|
0
|
0
|
0
|
|
Fung-shui forest
|
0
|
0
|
0
|
|
Semi-natural
secondary woodland
|
0
|
0
|
0
|
|
Plantation forest
|
0
|
0
|
0
|
|
Grassland
|
0
|
0
|
0
|
|
Grassland – shrubland mosaic
|
0
|
0
|
0
|
|
Landscaped area
|
0
|
0
|
0
|
|
Works in progress
|
0
|
0
|
0
|
|
Wasteland
|
0
|
0
|
0
|
|
Developed area
|
0
|
0
|
0
|
|
TOTAL
|
4.00
|
76.11
|
80.11
|
12.4.5
Discussions with operators
reveal that the dominant approach to aquaculture at Fung Lok Wai is freshwater
polyculture with most farmers stocking 6-7 species concurrently. The main
species stocked are Grey Mullet, which tends to comprise approximately 70% of
stock with the remaining 30% comprising: Tilapia species, Carp species (eg
common carp) and Bighead.
12.4.6
Data on the total production
(total weight) and market value of fish raised at Fung Lok Wai are not
available. Furthermore, estimates for aquaculture productivity within Hong Kong vary. AFCD data for Hong
Kong as a whole indicate that in 2001, within inland waters
approximately 1,059 ha
of fishponds produced 2,550 tonnes of fish at a combined market value of $41
million (AFCD 2002). This suggests an average productivity of approximately 2.4
tonnes per hectare per year. This figure includes, however, ponds in varying
states of productive use and is unlikely to reflect practice in the Deep Bay
where ponds are amongst the most intensively farmed within the territory.
12.4.7
In contrast, discussions with
operators in the Deep
Bay area undertaken by WWF
(T. Lau pers. comm.) suggest an average annual productivity figure of over 9
tonnes per hectare is regularly achieved and discussions with some operators at
Fung Lok Wai indicate productivity closer to 12.5 tonnes per hectare per year.
12.4.8
Profitability of fishfarming
operations is clearly highly variable between operators. The industry has been
facing competition from China.
To maintain profitability some operators have sought to raise income by
increasing the stocking proportion of higher value species such as Grey Mullet
whilst at the same time limiting costs by, for example, reducing the frequency
of maintenance activities and increasing the frequency of harvesting.
12.4.9
Previous investigations into
fisheries operations in the Deep
Bay area (e.g. BBV 2002)
and discussion with WWF (T. Lau, pers comm.) suggest that a profit of between
$40,000 - $50,000 per hectare per year is made. Discussions with the operators
at Fung Lok Wai suggested even higher figures of $60,000 to $75,000 per hectare
per annum.
12.4.10
It should be noted that many
farmers operate small operations of 1 or 2 ponds and supplement their income
from other sources. Some of these farmers will choose not to maximise the
productivity of their ponds and be satisfied with both lower income and
productivity than the figures presented here.
12.4.11
Traditionally managed
aquaculture ponds also produce a non-commercial by-product in the form of small
fish and crustaceans including: Small Tilapia (O. mossambicus), Mosquito fish (G.
affinis) and Prawns (M. nipponense). The availability of these species to feeding
birds during pond drain down is a
key feature of their ecological value and importance for
conservation.
12.4.12
The combined mean weight of
non-commercial by-product for ponds in Deep Bay
is estimated at approximately 260
kg/ha (Aspinwall 1997, Primavera 2000). On this basis, assuming that all actively
managed ponds operated within the Assessment Area were managed according to
traditional polyculture practice, the total annual yield of non-commercial
species at Fung Lok Wai would be approximately 16.4 tonnes.
Other aquaculture activities
12.4.13
Deep Bay is the location for aquaculture practices including oyster culture.
12.4.14
Oysters have been cultured
along the intertidal mud flat of Deep
Bay for over 200 hundred
years. Juvenile oysters are imported from the Mainland and grown out on rafts
in the shallow coastal waters of Deep
Bay. Oysters are also cultured in inter-tidal
areas on the seabed using concrete posts as clutches. In 2001 oyster meat production was estimated
at 115 tonnes worth about $5 million.
Marine and coastal fisheries
12.4.15
In 2001 AFCD (2002) indicate
that the marine fishing fleet in Hong Kong
produced an estimated 173,970 tonnes of fish valued at $1,730 million. 90% of
this total catch comes from waters outside Hong Kong.
The industry comprises approximately 4,500 fishing vessels employing 192,000
fishermen.
12.4.16
Within Hong
Kong waters production is estimated at around 18,000 tonnes with
most caught in north-eastern waters. Whilst Deep Bay
is not considered a particularly important area for net fishing, it is an
important area for crustaceans particularly Trachypenaeus
curvirostris. Dominant species caught in Deep Bay included Panaeidae (prawns), Sciaenidae (croaker) and Squillidae
(mantis shrimp). Of the eighteen sites
sampled in Hong Kong marine waters by shrimp trawlers during the AFCD baseline
fisheries survey conducted in 1996 the highest diversity of species of were
caught in Deep Bay.
Scoping
12.5.1
The nature of the proposal
means that most direct and indirect impacts will be constrained to the
Assessment Area, that is the proposed Development Area and the area proposed
for the construction of the Wetland Nature Reserve.
12.5.2
The potential for off-site
impact on adjacent fishponds and mariculture and marine and coastal fisheries
resources within Deep
Bay has been considered.
The outcome of the water quality impact assessment, however, indicates that the
probability of off-site impacts through discharge or surcharge of contaminated
water is extremely low. Normal precautions will be undertaken to restrict
discharge of sediment and waterborne pollutants during construction. During
operation stormwater run-off will be diverted to the storage pond of the WNR.
In the event that severe rainfall causes surcharging of fishponds and marsh
habitats, is unlikely to cause impact to neighbouring ponds and estuarine and
marine receiving waters because:
·
Only limited water will be
discharged from the WNR to the surrounding (mostly flow through the Tai River
with poor existing water quality). Water can be recirculated back into the
storage pond when needed. In any event the predicted water flow of the WNR is
very similar to existing situation, i.e. stormwater from catchments and water
from fishponds already flow into the Tai
River.
·
No pesticides and herbicides
will be added and discharged during the construction and operation of the WNR.
·
Storage and settling of
catchment water within the storage pond is likely to improve water quality,
particular in relation to suspended solids.
·
The isolated fishponds in the
WNR will only discharge water to the surrounding during flooding event. As
average water depth of the fishponds will be maintained lower than those
existing ponds, the threat of flooding will be reduced compared to the existing
situation.
12.5.3
The preferred option for the
disposal of sewage is Strategy A2 described in Chapter 8. New sewage pipes laid under
this strategy (and Strategy A1) follow existing roads and avoid aquaculture
ponds. In any event the use of twinned sewage pipes will enable the impacts of
sewer bursts to be controlled. The risk of significant impact arising from
pollution due to pipe failure is, therefore, considered to be extremely small.
12.5.4
Strategy B follows a western route
and would involve the laying of pipes beneath the freshwater marsh and adjacent
to three ponds located to the west of the Assessment Area. During the site
assessment undertaken in January 2001, two of these ponds were found to be
inactive, although the status of ponds can change. As in Strategy A, the use of
twinned pipes will enable control of sewage in the event of a burst pipe.
Whilst the risk is low, the magnitude of any impact arising because of a sewage
leak along this route would be greater than for Strategy A2 (or A1) due to the
proximity of the ponds.
12.5.5
All strategies, however,
involve the construction of an on-site sewage pump house. In the event of an
emergency or power failure, sewage may need to be diverted past this station.
To avoid potential impact a by-pass pipe will be installed to direct sewage to
the Tai River via Channel “X” thus avoiding the
potential for contamination of aquaculture ponds.
12.5.6
The Assessment Area is not an
important breeding or nursery ground for commercially important species of fish
(ERM, 1998).
12.5.7
Consideration of potential
impacts within the Assessment Area, therefore, indicates the following are
likely to occur as a result of the proposal:
·
Construction phase
o
Permanent loss of aquaculture
ponds; and,
o
Temporary loss of aquaculture
ponds.
·
Operational phase
o
Modification of aquaculture
ponds including reduced intensity of aquaculture operation.
Evaluation of the significance of
impacts
Construction phase
Permanent loss of aquaculture ponds
12.5.8
The Project involves the construction of the Wetland Nature Reserve
comprising enhanced and enlarged fishponds, rain fed ponds for water birds and
a complex of freshwater marshlands and the construction of residential
development. The design principles of no net loss of waterbody area and
functional enhancement of wetland habitats are to be achieved through the
reconfiguration of pond bunds to create larger and functionally enhanced ponds
which are more preferred by birds and to create land for residential
development. Through the pond bunds reconfiguration, there will be a slight
increase in area of water body within the Site.
12.5.9
Construction of the proposed
development, including the Wetland Nature Reserve will result in the permanent
conversion of 19 complete ponds and about one third of an additional pond, a
total area of approximately 18.4
ha, to residential development and freshwater marsh. Thirty-one
of the remaining 37 ponds will be consolidated to 18 larger ponds which will
continue to be managed as fishponds, although in modified form (see below). The
remaining 6 ponds will be taken out of production (consolidated into 3 larger
ponds) and managed as rain fed ponds for duck and other water birds.
12.5.10
In total, therefore, 25 whole
ponds and approximately 1/3 of an additional pond (approximately 26.2 ha.) will be permanently converted
to non-production uses. Of these, 6 (approximately 5.4 ha) were characterised as “unmanaged” at the time
of the survey, so the loss of productive ponds equates to approximately 20.8 ha.
12.5.11
Based on an anticipated gross
productivity in the range 9-12.5 tonnes of freshwater fish per hectare per
annum, this removal equates to a loss in gross annual productivity of 187-260
tonnes of fish worth approximately $3-$4.2 million at an assumed average market
price of $16 per kg (See Table
12‑7).
Table 12‑7 Wholesale price range
per kg of freshwater fish during the period January – December 2001. Source:
AFCD, fax 11/9/02
|
Species
|
Price range ($)
|
Average ($)
|
|
Grey Mullet
|
12.20 – 16.70
|
14.30
|
|
Silver Carp
|
5.80 – 7.00
|
6.20
|
|
Big Head
|
11.60 – 14.00
|
12.80
|
|
Grass Carp
|
11.60 – 13.70
|
12.60
|
|
Tilapia
|
5.50 – 7.80
|
6.60
|
|
Common Carp
|
5.50 – 8.40
|
6.80
|
|
Mud Carp
|
15.60 – 18.40
|
16.80
|
Temporary loss
12.5.12
On acquisition of the site all
ponds will be taken temporarily out of production and managed according to an
interim management regime whilst the Wetland Nature Reserve is constructed.
This management regime will focus on the production of “trash fish” for bird
species of conservation importance, particularly herons and egrets, and
involves:
·
Correcting the pH of the water
·
Stocking those ponds that are
fish depleted with “trash fish” species
·
Periodically draining down
designated ponds according to a pre-determined schedule
·
Re-correcting pH and re-stocking
as required
12.5.13
The programme and methods of
pond enhancement are detailed in the Fung Lok Wai Habitat Creation
and Management Plan that accompanies this EIA report.
12.5.14
Briefly, however, it will
involve the temporary drainage and reprofiling of 37 of these ponds. As
indicated above six of these will be permanently taken out of production and
consolidated into 3 larger ponds. Works on the remaining 31 ponds will be
staged so at any point in time only two or three ponds (adjacent pairs or
triplets) will be drawn down and re-profiled.
12.5.15
With respect to aquaculture
operations, however, the key issue is the timing and sequencing of pond
enhancement works. To reduce disturbance of valued ecological components
associated with the use of heavy machinery, pond enhancement works will be
staged. Three sectors of ponds have been defined (Figure 12‑2) within which works will be conducted sequentially
according to the schedule identified in Table
12‑8.
Table 12‑8 Schedule
for pond enhancement works. Bund numbers are illustrated in Figure 12‑2
|
Sector
|
Expected duration of works
|
Expected completion of
enhancement works (indicative)
|
Time out of production
|
Expected time under interim
management
|
|
Sector 1 pond bunds:
1, 2, 3, 4, 5, 6, 7
|
13 weeks
|
March 2011
|
Approx. 9 months
|
66 months
|
|
Sector 2 pond bunds:
9, 10, 29
|
6-7 weeks
|
September 2011
|
Approx. 15 months
|
60 months
|
|
Sector 3 pond bunds:
8, 11, 12, 14, 15, 16
|
14 weeks
|
September 2012
|
Approx. 21 months
|
54 months
|
12.5.16
After completion of enhancement
works the ponds will be placed under interim management as part of the
mitigation strategy for predicted ecological impacts arising from Residential
Development construction as described in Section 13. Interim management will
involve stocking ponds at artificially high densities and extending the draw
down periods of the ponds to encourage higher piscivorous bird densities. The
sequencing of works and the periods during which ponds will be under different
management regimes in summarised in Figure 13-13. The length of time that ponds
will be out of production or under interim management will vary (see Table 12‑8). The maximum period that ponds will be completely
out of production will be 21 months (in the case of Sector 3) and the maximum
period that ponds will be under the interim management regime will be 66 months
(Sector 1). On completion of the development works (duration about 75 months)
all ponds will be returned to polyculture operation with some amendments (see
below). It is anticipated that this will occur from October 2016
onwards.
Operational phase
Modified production within WNR
12.5.17
During the process of enhancement
31 ponds will be consolidated into 18 of total area of about 47.0 ha. average size 2.6 ha (the average size of existing
ponds is about 1.5 ha.).
12.5.18
Following completion of
enhancement works, these 18 ponds will be managed according to a modified traditional
commercial aquaculture procedures involving stocking, rearing, harvesting and
periodic set-aside for maintenance and recovery with several key differences:
·
The management of the 18 ponds
in active production will be coordinated. Most farmers typically operate a
handful of ponds at the same time. The management of such a large block of
ponds en masse will allow for a coordinated approach to fish production,
maintenance and monitoring activities. It will also facilitate a more effective
approach to their adaptive management.
·
Ponds in production will be
drained down annually for a fixed period of 20 days. Ponds are typically drawn
down for shorter periods under normal management regimes.
·
Approximately 25% of ponds will
be “set-aside” for production according to a 5 yearly schedule. This will
provide opportunity for maintenance works and allow for control of diseases or
presence of undesirable species. Set-aside is a more ad hoc process under
normal management procedures.
·
Whilst most fish selected for farming
will be those typical of commercial aquaculture operations, the composition and
proportions of these species will be varied to benefit feeding wildlife to meet
HCMP targets. This may result in a reduction of the productivity expected
within purely commercial operations.
12.5.19
The introduction of measures to
encourage increased wildlife usage are expected to reduce commercial
productivity. The magnitude of reduction is not known precisely, but is
expected to be in the region of 20%. For the purposes of this assessment, it is
assumed, therefore, that productivity rates will be about 80% of the average
for traditional commercial polyculture.
12.5.20
At assumed levels of production
(between 9-12.5 tonnes per ha) 46.65
ha of ponds would be expected to produce between 420-583 tonnes
of fish per annum. At the reduced levels of productivity envisaged this figure
equates to 336-467 tonnes per annum, or a “loss” of productivity of between
84-116 tonnes per annum.
Summary of predicted impacts
12.5.21
The proposed development will
result in the permanent loss of 20.8
ha. of active commercial fishpond and 5.38 ha. of inactive ponds. Associated lost
productivity equates to approximately 187-260 tonnes of fish worth
approximately $3-$4.2 million at an assumed average market price of $16 per kg.
12.5.22
During the first two years of
construction all ponds will be taken out of production with some being
converted to other uses and 46.65
ha. being progressively reprofiled. Following pond enhancement
works the ponds will be placed under an interim management regime, designed to
improve their attractiveness to wildlife, particularly birds, until completion
of the Residential Development construction works. The total period that ponds
will be take out of production to allow enhancement works or under the interim
management regime will be approximately 75 months.
12.5.23
On completion of the
Residential Development the ponds will be returned to a modified traditional
management practice as part of the long-term management strategy for the WNR.
Under this management regime, the ponds will operate at about 80% of the
productivity of average commercial polyculture ponds.
12.5.24
As no significant off-site
impacts associated with construction activities or operation are anticipated,
the risk of impact to adjacent fishponds and Deep Bay
mariculture, oyster farming and marine fishing activities is considered to be
very low.
12.5.25
On the basis of the information
in this chapter regarding fish pond management and associated socio-economic
issues, an overall evaluation has been prepared in Table 12‑9 using the criteria listed in Annex 9 of the EIA
Ordinance Technical Memorandum.
Table 12‑9 Summary of importance of the fisheries resources within the Fung
Lok Wai Assessment Area and evaluation of predicted impacts
|
|
Evaluation
|
|
Criteria
|
Aquaculture
|
Oyster farming
|
Marine & coastal fishing
|
|
Size
|
Active:
62.44 ha.
Inactive: 8.16 ha.
|
Small
areas within Deep
Bay
|
N/A
|
|
Typical
resources/ production within the Assessment Area
|
Freshwater
fish: 562-781 tonnes per annum
|
None
within Assessment Area
|
None
within Assessment Area
|
|
Typical
production in Hong Kong
|
2,550
tonnes per annum
|
115
tonnes per annum
|
Marine
fish: 18,000 tonnes per annum
|
|
Number
of operators within the Assessment Area
|
21
known
|
None
|
None
|
|
Evaluation
of importance of resource within the Assessment Area
|
Moderate
|
N/A
|
N/A
|
|
Nature
of impacts
|
Conversion
of some ponds to non-productive uses
Modification
of management of remaining ponds to less productive operation
|
Potential
for indirect impacts due to release or surcharge of poor quality water.
Standard pollution control procedures are expected to mitigate these
potential impacts
|
Potential
for indirect impacts due to release or surcharge of poor quality water. Standard
pollution control procedures are expected to mitigate these potential impacts
|
|
Destruction
and disturbance of nursery and spawning grounds
|
None
|
None
predicted
|
None
predicted
|
|
Size
of area affected
|
Permanent
loss of 26.2 ha
Temporary
loss of 46.65 ha for a
period of 75 months (including during enhancement works and during interim
management).
Reduced
long-term production within 46.65
ha.
|
None
predicted
|
None
predicted
|
|
Loss
of fisheries / resource production
|
Permanent
loss: Estimated between 187-260 tonnes per annum productivity
Loss
due to reduced productivity within Wetland Nature Reserve ponds: 84-116
tonnes per annum (assumes 80% of existing productivity)
Total
loss: between 271-376 tonnes per annum
|
None
predicted
|
None
predicted
|
|
Overall
impact
|
Moderate
|
None predicted
|
None predicted
|
Cumulative impacts
12.5.26
Other significant projects
within Deep Bay that may also result in temporary or
permanent loss or modification of fishponds include:
·
Improvements to San Tin Interchange
(EIA093/2004) – An EIA report was approved under the EIAO on 3/5/2004. The report concluded that the project would
not caused direct loss of existing fish ponds.
·
KCRC Sheung Shui - Lok Ma Chau Spur Line (EIA-071/2001) – approved in April
2002, the EIA report for this project predicts the permanent loss of 0.4ha of active aquaculture ponds and a
further 9.2 ha of inactive
ponds. As compensation for predicted ecological impacts, at least 27.1 ha of disused fishponds will be
re-established and managed in a traditional polyculture approach with
enhancements to favour wildlife in the Lok Ma Chau area. Station construction and wetland
compensation works has been completed.
·
The EIA report of Yuen Long and Kam Tin Sewerage and
Sewerage Disposal Stage 2 (EIA-074/2002) – approved in August 2002 under EIAO
stated that this project will result in a small loss of
approximately 0.15 ha.
of inactive ponds.
12.5.27
There are other concurrent
projects but none of these are expected to result in significant loss of
fishponds or result in impact to fisheries resources.
12.6.1
Key mitigation measures to be
incorporated into construction procedures to protect the water quality of
fishponds within the Fung Lok Wai Assessment Area, adjacent fishponds and Deep Bay
estuarine and marine environments are outlined in the section addressing Water
Quality Impacts.
12.6.2
A key objective of the
Wetland Nature Reserve is to continue traditional polyculture aquaculture, in
modified form, within a substantial area of aquaculture ponds. These ponds will
be run on commercial lines, in a way that is consistent with the conservation
objectives of the Wetland Nature Reserve. Against the backdrop of a marked
decline in fishpond activities within Hong Kong,
the incorporation of these activities within the management framework of the
Wetland Nature Reserve ensures a degree of security of operation that cannot
now be guaranteed elsewhere.
12.7.1
Consistent with the adaptive
management framework proposed for the ongoing management of the Wetland Nature
Reserve, a monitoring programme will be instituted to assess the success of
fisheries production and to identify requirements or potential for
modification. Whilst the primary objective of management is the achievement of
conservation objectives, commercial fish production practices will continue to
form a key element
of the operation of the Wetland Nature Reserve.
12.7.2
Details of monitoring along
with action levels and limits are included in the Habitat Creation
and Management Plan.
12.8.1
Aquaculture in Hong Kong is declining because of increased competition
from mainland suppliers and other poorly understood social processes. The
result is increasing abandonment of fishponds and their conversion to other
uses. Whilst there has been some move to intensive monoculture rearing, this
still accounts for about 5% of productive ponds in Hong
Kong. The same economic forces that are driving abandonment of
polyculture ponds may also undermine the profitability of monoculture
operations.
12.8.2
The proposed development at
Fung Lok Wai will result in the loss of some ponds. Those ponds that remain,
however, will be enhanced to increase their ecological values, primarily for
bird Species of Conservation Importance. They will, however, continue to be managed
in largely traditional manner within which fish production will still be a key objective. The establishment
of the Wetland Nature Reserve will ensure that this enhanced management regime
is implemented in
the long-run. In this respect the fish production and
fishponds will enjoy greater security than comparable ponds elsewhere within Deep Bay.
12.8.3
The long-term management of
these ponds ensures the preservation of the cultural practice of aquaculture
in-situ, which is consistent with concepts of “wise use” fore-shadowed in
Article 3.1 of the Ramsar Convention. It also provides opportunities for
ongoing research into sustainable fish production and wildlife conservation.
12.8.4
Off-site impacts are not
predicted as the likelihood of adverse impacts on water quality of neighbouring
ponds, estuarine and marine receiving environments is considered to be very low
during either construction or operation phases.
1.
(AFCD) Agriculture, Fisheries
and Conservation Department (2002) Fisheries website. [URL] www.afcd.gov.hk
2.
Aspinwall (1997). Study on the
Ecological Value of fish Ponds in Deep Bay Area: Executive Summary. Planning
Department, Hong Kong SAR Government.
3.
Aspinwall Clouston &
Wetlands International – Asia Pacific (1997).
Development of a comprehensive conservation strategy and a management plan in
relation to the listing of Mai Po
and Inner Deep Bay
as a Wetland of International Importance under the Ramsar Convention. Agreement No. CE47/95.
4.
Binnie, Black & Veatch
(2002). Sheung Shui To Lok Ma
Chau Spur Line Environmental Impact Assessment Report.
Kowloon Canton Railway Corporation, January 2002.
5.
Cheung,
Y.M.J. (1999)
The socio-economics of pond-fish farming and its implications on future land
use in and around Mai Po
and Inner Deep Bay Ramsar Site. Master
of Science of Environmental Management dissertation.
6.
Environment Protection
Department (2000). EAI Study Brief (ESB-055/2000) for Proposed Development at
Fung Lok Wai, Yuen Long at lot 1457 RP in DD 123. EPD, Hong
Kong.
7.
ERM (1998). Fisheries Resources
and Fishing Operations in Hong Kong Waters. Report for Agricutlure, Fisheries
and Conservation Department.
8.
Everitt, S. & Cook, J. (1997) Regional Study and Workshops on
Aquaculture: Sustainability and the Environment. Hong Kong Study Report. Asian Development Bank.
9.
Melville,
D.S. & Morton, B. (1983). Mai Po Marshes.
World Wildlife Fund for Nature Hong
Kong, Hong Kong.
10.
Primavera, J.H. (2000).
Integrated Mangrove – Aquaculture Systems in Asia.
Integrated Coastal Zone Management, Autumn edition, pp. 121-130.
11.
Townland Consultants Ltd, Wong
Tung & Partners Ltd, Maunsell Consultants Asia Ltd, MVA Asia Ltd, CES Asia
Ltd, Belt Collins & Associates HK ltd, Nelson and Wright (1992). Sunnyville
Estate development at Nam Sang Wai, Engineering Assessment Report, Nam Sang Wai
Development Co, Ltd & Kleener Investment Ltd.
12.
Young, L. (1991). Conservation
of wildlife in the Deep
Bay area: with particular
reference to heron species. pp. 813-822. In: Boxall, J. (ed.) Polmet '91;
Pollution in the metropolitan and urban environment. Hong
Kong Institution of Engineers, Hong Kong.
13.1.1
This section presents the
findings of this assessment which includes consideration of the potential and
predicted impacts associated with the construction and operation of: a
residential development, an access road, sewerage facilities (including pump
house and pipeline) and an on-site wetland nature reserve.
13.1.2
The Fung Lok Wai site comprises
approximately 80.1 hectares of which about 4.0 hectares (5%) will be affected
by the residential development and associated access roads. The remaining 76.1
hectares (excluding the access road) will form the Wetland Nature Reserve
(WNR). Figure
13‑1 illustrates the site boundary and extent of
ecological assessment. For the purposes of this assessment the following areas
were defined:
·
Proposed Development Area – the
area directly affected by residential construction;
·
Wetland Nature Reserve – the
area of fishpond enhancement and marshland creation;
·
Study Site – comprising the
Proposed Development Area, the proposed Wetland Nature Reserve;
·
500m Buffer Zone – the
buffer established around the Study Site including the access road for the
purposes of the assessment impacts on terrestrial habitats in accordance with
the EIA study brief;
·
Assessment Area – comprising
the study site and the buffer zone.
Scope and aims of this Ecological Impact
Assessment
13.1.3
In accordance with Section 3.5.6.2
of the Study Brief the spatial extent of this assessment comprises:
·
all terrestrial and freshwater
aquatic habitats present within the boundary of the proposed development and
surrounding 500m buffer
zone; and
·
marine habitats within the
entire extent of the Deep Bay Water Quality Inner and Outer sub-zones (DM3)
(EPD, 2000).
13.1.4
The aims of this assessment are
to provide sufficient and relevant information to assist the Environmental
Protection Department (EPD) and the Agriculture, Fisheries and Conservation
Department (AFCD) to:
·
Identify, assess and evaluate
the ecological resources (i.e. Valued Ecological Components (VECs) and Species
of Conservation Importance (SoCI)) that will be affected by construction and
operation of the proposed development;
·
Identify, assess and evaluate
any adverse ecological impacts that will arise during the construction and
operation of the proposed development, and evaluate the acceptability of these
impacts;
·
Identify, assess and evaluate
the effectiveness of proposed mitigation measures that will be adopted to
minimize or eliminate the predicted ecological impacts that will arise during
the construction and operation of the proposed development;
·
Identify, assess and evaluate
the predicted residual ecological impacts that will arise as a result of the
construction and operation of the proposed development following implementation
of the proposed mitigation measures;
·
Evaluate the acceptability of
these residual impacts once the proposed mitigation measures are implemented;
and,
·
Identify, assess and evaluate
the effectiveness of proposed wetland compensation measures, in the form of an
on site WNR.
Specific objectives of this assessment
13.1.5
The EIA study brief for this
proposal (EPD, 2000) identifies specific objectives and requirements for the
Ecological Impact Assessment. The relevant sub-section within which each of
these objectives is addressed is indicated as follows:
·
review and incorporate the
findings of relevant studies including the Tin Shui Wai Development Engineering
Investigations for Development of Area 3, 30 & 31 of the Development Zone
and the Reserve Zone and collate all the available information regarding the
ecological characters of the ‘‘Assessment Area’’. Details of the literature
review undertaken during the investigation are provided in Section 13.3 and
Section 13.4.1 – 13.4.40;
·
identify any information gap
relating to the assessment of potential ecological impacts to the terrestrial
and aquatic environment. Key information gaps are summarised in Section 13.4.41
– 13.4.42;
·
carry out any necessary field
surveys, the duration of which shall be at least 12 months and cover the winter
migratory bird season, and investigations to fill in the information gap, if
any, and to fulfil the objectives of the EIA study. Details of the baseline surveys
undertaken over 12 months are described in Section 13.5;
·
establish the general
ecological profile and describe the characteristics of each habitat found
within the study boundary, committed ecological measures including those under
the EIA Ordinance or the Town Planning Ordinance (such as reinstatement of
fishponds) should be taken into consideration; major information to be provided
shall include:
o
description of the physical
environment (addressed in Section 13.2);
o
habitat maps of suitable scale
(1:1000 to 1:5000) showing the types and locations of habitats in the
‘’Assessment Area’’ (provided in Figure
13‑9);
o
ecological characteristics of
each habitat type such as size, vegetation type, species present, dominant
species found, species diversity and abundance, community structure,
inter-dependence of the habitats and species, and presence of any features of
ecological importance (details provided in Section 13.6);
o
representative colour
photographs of each habitat type and any important ecological features
identified (included in Appendix 13-2);
o
species found that are rare,
endangered and/or listed under local legislation, international conventions for
conservation of wildlife/habitats or red data books (addressed in Section 13.6
and summarised in paragraphs 13.6.79 – 13.6.82);
·
investigate and describe the
existing wildlife uses of various habitats with special attention to:
o
wetlands including fish ponds,
wet agricultural land, marsh;
o
avifauna;
o
fung shui woodland;
o
natural stream courses and man
made drainage channels; and
o
any other habitats and wildlife
groups identified as having special conservation interests by this study (the
habitats each species are associated with are described in Section 13.6).
·
describe all recognized sites
of conservation importance in the proposed development site and its vicinity in
particular the Deep Bay Wetland Conservation Area, Wetland Buffer Area, Mai Po Inner Deep Bay
Ramsar Site and Tin Shui Wai Wetland Park (now called Hong Kong Wetland Park)
and assess whether these sites will be affected by the proposed developments or
not (recognised sites of conservation importance are described in Section 13.4 a description of the potential affects
of the proposed development on these sites is included in Section 13.8.1
– 13.8.6);
·
investigate the impact of the
high rise residential buildings in the project area on the bird’s flight path
taking into account of diurnal and seasonal patterns (the effects of the
construction of high rise buildings on the flightpaths of birds are analysed in
detail in paragraphs 13.6.68 – 13.6.76 and under “Habitat Fragmentation” in
Section 13.7);
·
using a suitable methodology,
identify and quantify as far as possible any direct, indirect, onsite, primary,
secondary and cumulative ecological impacts such as destruction of habitats,
reduction of species abundance/diversity, loss of feeding grounds, reduction of
ecological carrying capacity, loss in ecological linkage and function, habitat
fragmentation and other possible disturbances caused by the development of the
project and the activities of the residents (the potential effects of the
development are assessed in Section 13.7);
·
evaluate the significance and
acceptability of the ecological impacts identified using well-defined criteria
(the significance of potential impacts are evaluated in Section 13.8);
·
recommend all possible
alternatives (such as modifications of layout and design) and practicable
mitigation measures to avoid, minimize and/or compensate for the adverse
ecological impacts identified (mitigation options are described in Section
13.9);
·
evaluate the feasibility and
effectiveness of the recommended mitigation measures and define the scope,
type, location, implementation arrangement, subsequent management, resources
requirement and maintenance of such measures (the feasibility and effectiveness
of mitigation measures is discussed in Section 13.9);
·
determine and quantify as far
as possible the residual ecological impacts after implementation of the
proposed mitigation measures (residual impacts are described in Section 13.10);
·
evaluate the severity and
acceptability of the residual ecological impacts using well-defined
criteria. If off-site mitigation
measures are considered necessary to mitigate the residual impacts, the
guidelines and requirements laid down in the TM shall be followed (residual
impacts are described in Section 13.10);
·
review the need for and
recommend any ecological monitoring programme required (see Section 13.11).
·
propose a management package
for the 71.6 ha
Wetland Nature Reserve in the project area with particular attention to (the
design and management of the WNR is summarised in Section 13.9 and described in
detail in Section 14. Financial and administrative details of the WNR are
described in Section 15.):
o
the habitat management plan and
specification of resources requirement for its implementation;
o
the long-term trust management
system with management guidelines;
o
the financial arrangement to
sustain the management of the wetland;
o
the management agents and their
responsibility;
o
a contingency plan for the
management of the WNR before the well establishment of trust management;
13.2.1
This sub-section provides
details of the geographical and physical context of Fung Lok Wai including past
and present land-uses, superficial geology, topography, hydrology and water
quality.
Location and Regional Context
13.2.2
The study site is located to
the south of Inner Deep Bay in
the North West New Territories
of the Special Administrative Region of Hong Kong. Figure 13‑2 illustrates the location of the Assessment Area in
the context of the Deep
Bay environs. To the west
the site is bounded by mangroves along the tidal creeks of the Tai River
outfall, beyond which are grasslands, reedbeds, a plantation and fishponds.
Further to the west of Fung Lok Wai is Tin Shui Wai New Town. To the north-west
there is an area of tidal lagoons (near Tsim Bei Tsui) created by the
construction of a causeway for the road and border security fence.
13.2.3
The site is bounded to the
north and east by wetland habitats. There is a continuous band of one or two
fishponds bound the site to the immediate north, beyond which lies a belt of
mangroves which give way to the tidal mudflats and increasingly marine
conditions of Inner
Deep Bay.
Further to the north-east, beyond the Shan Pui River, there is a large area of
fishponds and the Mai Po
Nature Reserve, a complex of mangrove, gei wai, reedbed and
fishponds. Fishponds also bound the site to the east, beyond which is a strip
of landscaped land either side of the closed area boundary road, which
demarcates the eastern extent of land reclamation. Further east is the Main
Drainage Channel for Yuen Long, Kam Tin and Ngau Tam Mei drainage from the Shan Pui
River. To the south east
lies Yuen Long Sewage Treatment Works to the south of which lies Yuen Long
Industrial Estate. The south of site is
bounded by undeveloped low hills. These are predominantly covered in
semi-natural scrub and woodland vegetation with some grassland and orchards.
Much of the lower lying areas have been developed for residential housing or
cultivated for wet and dry agricultural uses, depending on drainage conditions.
Tin Shui Wai new town lies to the south-west and in the western part of the
site there are large areas currently under construction relating to the ongoing
development of Tin Shui Wai and the operation of Hong Kong Wetland
Park.
Past and Current Land
Use
13.2.4
Originally the Deep Bay
area was dominated by brackish and freshwater marshland habitats. However, Deep Bay
and its surrounding areas have undergone significant changes over the last
century which have been discussed in a number of studies (Melville &
Morton, 1983; Young, 1991, Aspinwall Clouston and Wetlands International 1997).
13.2.5
Reclamation of marshes and
inter-tidal habitats took place predominantly from the last century until the
middle of this century, with 1,200
ha of land being reclaimed between 1903 and 1945. This land was
converted to agricultural use, mostly cultivation of brackish water rice and
shrimp production in gei wais (tidal shrimp ponds).
13.2.6
Between the mid 1960’s and 80’s brackish and fresh water rice cultivation
disappeared and almost all cultivated land and gei wais were converted to deep
water fishponds. By 1974, this had
become the dominant land use and provided an extensive area of wetland habitat.
However, by the same time, virtually all areas of natural and semi-natural
freshwater habitat had been lost.
13.2.7
From the late 1970’s to the present urban development
has taken over as the main pressure for change in the Deep Bay
area, the main impact being the infilling of fishponds and the use of the land
for housing, industrial estates and open industrial storage. Between 1985 and
1994, for example, the coverage of fishponds dropped from over 2,000 ha to 1,500 ha, representing a 25% decrease over 10 years.
13.2.8
Furthermore, many fishponds
have been abandoned which reduces their ecological value to many important
species, in particular herons and egrets. Of the fishponds remaining in the Deep Bay
area in 1994 only 78% were still actively managed (Everitt and Cook in press,
cited in Aspinwall Clouston and Wetlands International 1997), with the majority
located in the North West
New Territories,
mostly in or within the vicinity of the Mai Po Inner Deep Bay Ramsar Site.
13.2.9
The Fung Lok Wai site has shown
similar changes in land use as the Deep
Bay area as a whole. In
1924, it is understood that there was a number of large (presumably tidal) lagoons,
within the northern half of the site which is now included within the Mai Po Inner Deep Bay Ramsar Site. Some areas of
mangrove still appear to be present within the lagoons. The southern area of
the site which currently falls outside the Mai Po Inner Deep Bay
Ramsar site boundary but within the boundary of the Wetland Conservation Area
(WCA) includes some mangrove but also small rectangular fields, which were
probably brackish rice paddies.
13.2.10
An aerial photo dated November
1974 shows that most of the site was still tidal at this time; however a number
of fishponds had been established in the south-western portion of the site.
Since then, virtually the whole site has been converted to freshwater ponds,
the majority of which are currently actively used for freshwater fish farming.
Geology and Soils
13.2.11
The superficial geology of the
site consists of estuarine deposits of marine and fluvial origin, predominantly
silts and clays. No borehole information
is available from Fung Lok Wai itself, but investigations elsewhere indicate
that lenses of sands and gravels of alluvial origin may occur underneath the
surface estuarine deposits (see Townland et
al. 1992).
13.2.12
The soils of Fung Lok Wai are
derived from mangrove soils and ultimately have their origin as marine sediment
and riverine alluvium. Texturally the soils are dominated by silt and clay
fractions, the relative proportions of which produce soils that vary from clay
through silty clay to silty clay loam (USDA texture classes). Sand content is generally low. Very small
amounts of gravel are present. The soils have been considerably reworked during
reclamation and through management for fish-farming.
13.2.13
Soil samples taken in January
1996 were slightly acidic, with a mean pH of 6.8. The soils are poorly drained
and frequently highly saline, rendering them of little agricultural value.
Topography, Hydrology and
Watercourses
13.2.14
The site has an open, flat and
low lying aspect. The major variation in site level is due to the excavation of
the fishponds and creation of bunds. The level on top of the aquaculture pond
bunds vary from approximately +3.1 m
to +3.3 m PD, at the north
and east of the site, to about +4.2 m
PD at the south.
13.2.15
Water for the fishponds comes
from direct rainfall. During winter and when ponds are drawn down, water is
pumped from one pond to another to conserve resources. After heavy summer
rainfall, ponds may fill and drain into adjacent channels. Channels may also
occasionally be used for transferring water, by pump, between fishponds.
13.2.16
No flow data are currently
available for the drainage channels. However, a site inspection on 10th January
1998 revealed that all channels contained shallow water (c. 10 cm) and that there were low flows
from those draining catchments the adjacent catchments to the south.
13.2.17
The mangrove lined channel (Tai River
outfall) at the north-western perimeter of the site is intertidal. The perimeter bunds are approximately +3.8
mPD and higher than the predicted mean high water in the channel (+2.4 m PD). Therefore in normal circumstances
the interior of the site remains free of tidal influence. Overtopping of the
perimeter might occur in an extreme combined high tide and storm event.
However, this is likely to be extremely rare given the past extreme sea levels
at nearby Tsim Bei Tsui which peaked at +3.85 mPD with a return period of 100
years for records between 1974 and 1990. The predicted tidal range for 2002 at
Tsim Bei Tsui is 0-3 mPD with an average peak tide of +2.4 mPD.
Water Quality
13.2.18
The results of water quality
sampling in the fishponds at Fung Lok Wai undertaken in May 2002 (ALS
Technichem (HK) Pty Ltd) are shown in Table
13‑1 below. These data suggest that water quality in the
ponds is in accordance with the following AFCD (1995) recommendations for
fishponds: pH 6 - 8.5; dissolved oxygen > 1 mg/l; salinity < 2 mg/l.
13.2.19
Dissolved oxygen
concentrations, often regarded as the most important measure of water quality,
are high in all of the ponds measured, with the exception of Ponds 56 and 62
(see Figure
13‑1 for locations). High oxygen saturation levels are
perhaps not surprising given the widespread use of pond aerators by the fish
farmers.
13.2.20
No data are currently available
on the quality of water in the existing watercourses. However, all the
catchments are dominated by dense semi-natural scrub and woodland vegetation
and there are no apparent point sources of pollutants such as pig farms etc. It
is therefore expected that the water entering the site is likely to be of
relatively low nutrient status and with a low Biological Oxygen Demand (BOD).
It is also anticipated that suspended silt in runoff during heavy rainfall
periods is likely to be relatively low due to the existing dense vegetation cover
in the catchments. Further analysis of water quality survey results can be
found within the Water Quality Impact Assessment chapter of this EIA report.
Table 13‑1 Results of Water
Quality Monitoring in Fishponds at Fung Lok Wai (May 2002)
|
|
Sampled
Fish Pond
|
River
water Sampling Stations
|
|
Parameters
|
Pond
2
|
Pond
13
|
Pond
19
|
Pond
56
|
Pond
59
|
Pond
62
|
W1
(Shan Pui River)
|
W2
(Tai River)
|
|
pH
|
6.2
|
7.7
|
9.3
|
6.9
|
8.9
|
7.0
|
7.8
|
7.5
|
|
Conductivity (uS/cm)
|
2510
|
1860
|
635
|
1640
|
1100
|
1100
|
16500
|
21500
|
|
D.O. (mg/L)
|
5.4
|
4.4
|
7.2
|
2.6
|
8.2
|
2.4
|
3.1
|
2.1
|
|
% Saturation of D.O. (%)
|
72.5
|
62.2
|
98.1
|
38.5
|
108
|
28.1
|
41.7
|
28.7
|
|
Temp. (oC)
|
31.3
|
31.0
|
30.4
|
30.7
|
32.5
|
30.5
|
30.0
|
29.0
|
|
Salinity (mg/L)
|
1.1
|
0.5
|
0.3
|
0.7
|
0.5
|
0.5
|
8.8
|
11.9
|
|
Turbidity (NTU)
|
45.2
|
30.7
|
23.1
|
63.3
|
23.5
|
42.4
|
12.7
|
20.0
|
|
SS (mg/L)
|
72.7
|
57.0
|
28.3
|
93.7
|
47.0
|
49.7
|
32.3
|
26.3
|
|
Ammonia as N (mg/L)
|
0.03
|
0.03
|
0.04
|
2.96
|
0.07
|
0.39
|
5.4
|
2.8
|
|
Nitrate as N (mg/L)
|
<0.01
|
<0.01
|
<0.01
|
0.04
|
0.04
|
0.23
|
0.6
|
0.7
|
|
Nitrite + Nitrate as N (mg/L)
|
0.02
|
0.02
|
0.02
|
0.16
|
0.17
|
0.31
|
0.9
|
1.2
|
|
Total Kjeldahl Nitrogen as N (mg/L)
|
3.2
|
2.9
|
3.9
|
4.6
|
3.3
|
3.6
|
7.3
|
3.1
|
|
Total Nitrogen (mg/L)
|
3.2
|
2.9
|
3.9
|
4.8
|
3.5
|
3.9
|
8.2
|
4.3
|
|
Total Phosphorus (mg/L)
|
0.2
|
0.2
|
0.2
|
0.2
|
0.2
|
0.3
|
0.7
|
0.5
|
|
Reactive Phosphorus as P (mg/L)
|
0.03
|
0.03
|
0.02
|
0.02
|
0.03
|
0.02
|
0.6
|
0.4
|
|
BOD (mg/L)
|
10.0
|
8.7
|
14.3
|
5.3
|
9.0
|
4.7
|
3.0
|
<2
|
13.3.1
In order to identify key
ecological resources and issues, relevant reports and scientific papers have
been reviewed below. A key
objective of this review is to identify important information gaps and
appropriate strategies for additional data gathering. In particular, the
results of species and habitats surveys undertaken at Fung Lok Wai between 1994
and 1998 are drawn upon, (Mutual Luck Investment Limited 1998).
13.3.2
A full list of documents
referenced during the preparation of this EcIA is included in Section 13.12.
However, the following documents are particularly relevant to this assessment:
·
Bats of Hong
Kong. World Wide Fund for Nature, Hong Kong. Ades, (1990).
·
Classification system for
wetland type, Ramsar Bureau. www.ramsar.org
·
Development of a comprehensive
conservation strategy and a management plan in relation to the listing of Mai Po and Inner Deep Bay as a Wetland of International
Importance under the Ramsar Convention.
Agreement No. CE47/95. Aspinwall Clouston & Wetlands International –
Asia Pacific (1997).
·
Ecological impact study of
proposed development at Pak Hok Chau, Mai Po. Unpublished
report. Anon. (1993).
·
Ecological study on mangrove
stands in Hong Kong. Report submitted to AFD,
Hong Kong SAR. Tam, N.F.Y. & Wong Y. (1997).
·
Environmental Impact
Assessment: Towards Guidelines of Adoption under the Ramsar Convention.
Technical Session A of the 6th meeting of the conference if the contracting
parties, Brisbane, March 1996. Pritchard, D. E. (1996)
·
Fish Ponds in the Ecology of
the Inner Deep
Bay Wetlands of Hong
Kong. Asian Journal of Environmental Management. Vol 3, No. 1,
pp13-36. Chu, W. H. (1995)
·
Guidelines for application for
developments within Deep Bay Area under section 16 of the Town Planning
Ordinance. TPB PG-No. 12B.
Town Planning Board
(1999)
·
Hong Kong International Wetland
Park and Visitor Centre Feasibility Study – Preliminary Environmental
Review. Hong Kong
Tourist Association. Binnie Black and Veatch (1999).
·
Objection to Draft Lau Fau Shan
& Tsim Bei Tsui Outline Zoning Plan No. S/YL-LFS/1 – Alternative Proposal.
Volume 1 and 2. Mutual Luck Investment Limited (1998).
·
Pilot project to develop a
long-term strategy for the conservation of fish pond farming within the Mai Po and Inner Deep Bay Ramsar
Site. Funded by the Conservation
Foundation Fund, Hong Kong. World Wide Fund
for Nature (2003)
·
Ramsar Site Waterfowl
Monitoring Programme, Hong Kong Bird Watching
Society. Carey, G. (unpublished).
·
Reconnaissance survey of
benthic and pelagic fish pond fauna at Fung Lok Wai. Prepared for Mutual Luck Investment Limited.
Binnie Consultants Limited (1997a).
·
Sheung Shui to Lok Ma Chau Spur Line Environmental
Impact Assessment. Binnie Black and Veatch 2000.
·
Study on the Ecological Value
of fish Ponds in Deep Bay Area: Executive Summary. Planning Department, Hong Kong SAR Government. Aspinwall & Company Hong Kong Limited (1997).
·
Sunnyville Estate development
at Nam Sang Wai, Engineering Assessment Report, Nam Sang Wai Development Co,
Ltd & Kleener Investment Ltd. Townland Consultants Ltd, Wong Tung &
Partners Ltd, Maunsell Consultants Asia Ltd, MVA Asia Ltd, CES Asia Ltd, Belt
Collins & Associates HK ltd, Nelson and Wright (1992).
·
The Avifauna of Hong Kong. Hong
Kong Bird Watching Society, Hong Kong. Carey,
G.J. et al. (2001).
·
The importance to ardeids of
the Deep Bay
fishponds, Hong Kong. Biological Conservation.
84 (3): 293-300. Young, L.(1998).
·
The significance of drained
fishponds for wintering waterbirds at the Mai Po Marshes, Hong
Kong. IBIS, 139 (4): 694-698. Young, L. (1997).
·
Tin Shui Wai Development
Engineering Investigations for Development of Area 3, 30 & 31 of the
Development Zone and the Reserve Zone – Environmental Impact Assessment - Final
Assessment Report. Volumes 1 and 2,
February 1997. Territory Development
Department, Agreement No. CE 10/95. Binnie Consultants Limited (1997b).
·
Various issues of Porcupine!
Newsletter of the Department of Ecology and Biodiversity, Hong Kong University.
·
Wild Animals to Watch: Terrestrial and freshwater fauna of
conservation concern in Hong Kong. Memoirs of the Hong Kong
Natural History Society. Fellowes, J.R et al. (in 2002).
·
In formation about the wildlife
of Mai Po Marshes
available at http://www.wwf.org.hk/eng/maipo/wildlife/habitats.html
·
Yuen Long Bypass Floodway
Feasibility Study Environmental Impact Assessment Binnie Consultants Limited
(1998).
·
Yuen Long and Kam Tin Sewerage
and Sewage Disposal Stage 1 Sewers, Rising Mains and Ancillary Pumping
Stations: Environmental Impact Assessment and Traffic Impact Assessment
Studies. Environmental
Impact Assessment (Designated Elements) Final Report. ERM (May
2002).
13.4.1
The location of the proposed
development in relation to existing protected areas of high ecological value is
indicated in Figure
13‑2. The northern boundary of the Assessment Area adjoins
the Inner Deep Bay Site of Special Scientific Interest (SSSI) and the northern
half of the Assessment Area lies within the boundary of the Mai Po Inner Deep Bay Ramsar Site (a Wetland of International Importance
under the Ramsar Convention). The Deep Bay
area comprises natural and man-made wetlands (rivers, freshwater marshes,
fishponds, gei wais (tidal shrimp
ponds), mangroves, inter-tidal mudflats and the bay) which provide a wide range
of habitats that support a high diversity of biota (plants, insects, reptiles,
amphibians, birds, fish and mammals). To the north east is Tsim Bei Tsui
Egretry SSSI and to the west beyond the Shan Pui River is Mai Po Nature Reserve
and Mai Po Marshes SSSI.
13.4.2
The Mai Po Inner Deep Bay Ramsar site
is particularly important for waterbirds, including a number of globally
threatened species (Collar et al.
1994), species which regularly have high proportions of their global or
biogeographical wintering or passage populations within the site and species
that are of regional or local conservation importance. Deep Bay is also
important for a wide range of other migratory water birds, many of which are
listed for protection under the Convention on the Conservation of Migratory
Species of Wild Animals (Bonn Convention) of which the People’s Republic of
China is a party.
13.4.3
The Town Planning Board has
adopted a “precautionary approach” to development in the Deep Bay
area in view of the known intrinsic value of fishponds in ecological terms, and
the complex response of birds to future land use changes which has not been
fully understood (Town Planning Board 1999). The intention is to protect and
conserve the existing ecological function of fishponds in order to maintain the
ecological integrity of the Deep
Bay wetland ecosystem as
a whole. This “precautionary approach” is formulated with the support of
scientific surveys and analysis as provided in the Study on the Ecological Value
of Fish Ponds in the Deep Bay Area (Aspinwall Clouston & Wetlands
International - Asia Pacific, 1997).
13.4.4
The Wetland Conservation Area
(WCA) forms the core wetland area of Inner
Deep Bay
between Tin Shui Wai in the west and the Lok Ma Chau Boundary Crossing in the east and has been
designated for all continuous and adjoining fishponds within this area,
including those within the study site.
The intention of the WCA designation is to conserve the ecological value
of fishponds which form and integral part of the wetland ecosystem in the Deep
Bay Area. A Wetland Buffer Area (WBA) of 500m
to the landward side of the WCA has also been designated to protect the
ecological integrity of the WCA.
13.4.5
In considering development
proposals in the Deep Bay Area, the Town Planning Board adopts the Fish Pond
Study’s recommended principle of “no-net-loss in wetland” which provides for
the conservation of continuous and adjoining fishponds. The no-net-loss can
refer to both loss in “area” and in “function”. Wetland compensation is
required for any development requiring pond filling and mitigation measures
against disturbance are also required.
13.4.6
Management zonation has been
developed for the Mai Po Inner Deep Bay
Ramsar Site as part of its Comprehensive Conservation Strategy and
Management Plan (Aspinwall Clouston and Wetlands International 1997). The areas
within the Ramsar boundary to the west, north and east of the site have been
identified as Public Access Zones. According to the Strategy, “the purpose of
the Public Access Zones is to enable people to have unrestricted (but managed)
access to a part of the Ramsar site in order to appreciate its special value
and enjoy contact with wildlife. In addition it provides opportunities for:
public education, raising public awareness of the conservation values of the
site, particularly as they relate to the Ramsar criteria values and
biodiversity values; and quiet recreation relevant to the aforementioned
values”. The area of the Fung Lok Wai site within the Ramsar boundary was not included
in the Public Access Zone as the Strategy did not propose management zones for
privately owned land.
Habitats
13.4.7
As described in Section 13.2 Deep Bay
was originally dominated by a complex of natural wetland habitats, including
inter-tidal mudflats, mangroves and brackish and freshwater marshland. This
century large areas of these inter-tidal habitats have been reclaimed and other
wetlands drained, infilled or converted to artificial gai wais or fish pond
habitats. Consequently, only small areas of natural and semi-natural wetlands
remain in the Deep
Bay area, mainly around
Ma Tso Lung.
13.4.8
These changes in habitats will
have had profound impacts on the distribution and abundance of many species
that were originally associated with these natural wetland habitats. Although
data are not available to assess the longer-term impacts, it is generally
accepted that many wetland species that are currently rare or no longer occur
in Hong Kong formerly commonly occurred in the Deep Bay
area.
13.4.9
The remaining areas of wetland
habitats are of local and regional importance in their own right. The mangrove
forests at Mai Po
together with those in the other parts of Deep
Bay cover an area of some 400 ha and are the sixth largest protected
stand remaining in China.
Mangroves provide important habitats for wildlife but in Hong
Kong most other stands are relatively small and subject to
frequent human disturbance (Tam & Wong 1997). Reedbeds at Mai Po represent greater than 80%
of all reedbed habitat in Hong Kong are one of the largest remaining areas
known in Guangdong Province and 240 ha of traditionally operated shrimp ponds
represent one of the largest areas of this habitat left in southern China
(WWF 2000).
13.4.10
Despite the loss of areas of
natural and semi-natural wetlands to artificial habitats some of the more
recent changes are likely to have had beneficial effects for some species. In
particular, it is likely that the high productivity of the fish farming systems
and the availability of abundant food during fish harvesting periods has
maintained or increased populations of many water birds, including cormorants,
herons and egrets. The value of
fishponds to some specific groups, in particular to birds, has been well
studied (see below), although a comprehensive assessment of the importance of
different habitat types in the area of Inner Deep Bay, to different species groups, has
yet to be undertaken.
13.4.11
Chu (1995) undertook a review
of the ecological surveys carried out for five planning applications within the
Deep Bay area to assess the relative
importance of fishponds and associated habitats for wildlife. The review
demonstrates that fish pond areas can support a number of protected species and
are an important habitat for resident ardeids and migrant birds. In addition,
summaries of species known to be associated with fishponds have been produced
(Ades et al. 1995). These summaries
indicate that fishponds within the Deep
Bay area, although artificial, are an
integral part of the Deep
Bay wetland ecosystem.
Vegetation
13.4.12
Approximately 120 terrestrial
plant species have been recorded from the Deep Bay
aquaculture pond bunds (Chau, unpublished data). However, most of these are
common and widespread species (Ades et al.
1995).
13.4.13
Surveys of the vegetation
around the fishponds at Fung Lok Wai were undertaken on 9th November 1994, 28th
February 1995 and 16th May 1996. Additional species recorded during the course
of other visits to the site were also added to the plant species list. All
plant species encountered whilst walking the bunds were recorded, with an
estimate made of their abundance within the site.
13.4.14
Areas of mangrove vegetation
occurred immediately outside the site but none were found within its bounds. A
small population of the mangrove fern Acrostichum aureum
was, however, found in a drainage ditch in the western part of the site.
13.4.15
The bund vegetation at Fung Lok
Wai during this survey consisted predominantly of coarse grassland, composed of
common grasses and herbs. The vegetation is subject to frequent disturbance in
the form of cutting, burning, rubbish dumping and, when the ponds are reformed,
bulldozing. As a result of this
disturbance ruderal or 'weed' species are a prominent feature, some such as the
alien climber Mikania micrantha
having spread to form extensive patches.
13.4.16
The most interesting vegetation
community recorded within Fung Lok Wai during these surveys was that associated
with the drainage ditches. Apart from supporting predominantly alien trees and
shrubs on their banks, the drainage ditches also supported elements of wetland
vegetation. This ranged from areas of dense reed Phragmites communis and low scrub of Marsh Fleabane Pluchea indica to open marsh vegetation
of Cyperus sedge and other
marginal/emergent species. The relatively undisturbed nature and dense vegetation
found in many of these ditches provide cover for wildlife.
13.4.17
A total of 76 plants species
were recorded during these surveys. No unusual or rare plant species were
encountered.
Invertebrates
13.4.18
A survey of invertebrates
present in seven fishponds exhibiting a range of conditions was carried out on
4th and 9th November and 21st December 1994. Invertebrate species richness was
found to be very low in all of the surveyed ponds. The fauna of mature and
recently drained ponds was typically dominated by freshwater shrimps, almost
exclusively belonging to the genus Palaemon. Pelagic insects were very scarce,
with only a few backswimmers (Notonecta
sp.) being encountered in one of the ponds.
13.4.19
Shrimp were not detected in
recently re-filled ponds. Some of these ponds did, however, support large
numbers of non-biting midges (Chironomidae). Adult Chironomids were seen
emerging in abundance from a recently re-profiled and filled pond. Exuviae collected from this pond were identified
by Dr M. Learner, University College, Cardiff,
as belonging to three genera - Einfeldia,
Chironomus and Nilodorum (Einfeldia
being the most abundant).
13.4.20
Sieve sampling of bottom muds
in a re-profiled and re-filled pond, revealed the presence of large numbers of
benthic Chironomid larvae. These were
present in sediments c. 1 metre below the water surface. These were identified
as Einfeldia and Chironomus, with the former again the most abundant. Densities of
benthic larvae were estimated at approximately 1,800 m-2.
Gelatinous egg masses, also belonging to chironomids, were found around
the margins of recently re-filled ponds, attached to clumps of clay just below
the water surface.
13.4.21
A further study of three ponds
at Fung Lok Wai in March 1997 also confirmed that Chironomid larvae are the predominant
benthic species present, followed by tubificid worms (Binnie Consultants
Limited 1997b). In total only 14 benthic taxa were recorded.
13.4.22
Searches of micro-habitats
around the margins of ponds revealed a number of crabs (Varuna litterata).
13.4.23
30% of all dragonfly species
recorded in Hong Kong can commonly be
encountered around managed fishponds. Most of these are generalists which
prefer static conditions and, in comparison to natural ponds and lakes, managed
fishponds support a reduced number of dragonfly species (Wilson 1995a & b).
Two species of dragonfly and damselfly of conservation interest have
been recorded with the Deep
Bay area though not
within the Assessment Area of Fung Lok Wai, Orthetrum
poecilops poecilops and Mortonagrion
hirosei. Orthetrum poecilops poecilops is normally associated with
woodland. Mortonagrion hirosei is usually confined to dense Phragmites reed
beds, so both are unlikely to occur within the Study Site.
13.4.24
Invertebrate surveys of bund
habitats were undertaken within three sampling areas of aquaculture ponds
within the Deep Bay area as part of the Fishpond Study
(Aspinwall Clouston & Wetlands International – Asia Pacific 1997). The
results of the survey indicate that the ponds support an impoverished and very
simple aquatic invertebrate community. Freshwater shrimps are the predominant
group. Present in large numbers, they are an important food source for herons
and egrets.
13.4.25
Aquatic insects are generally
quite scarce, except for Chironomid midges that were found in some abundance in
recently re-filled ponds. These insects are also important food sources for
birds, including Chinese Pond Herons and migratory passerines such as Acrocephalus warblers. The results
indicated that 46% of all invertebrates recorded were Chironomid midges, with
Hemiptera, Arachnida and other Diptera making up a further 42% of all records.
Total biomass peaked in spring. The greatest species group diversity occurred
within the scrub areas, though only by small margin; grassland areas supported
the greatest biomass and reedbeds the greatest density. All site surveys were
dominated by Diptera.
13.4.26
These findings are in broad
agreement with studies at Pak Hok Chau (fishponds near Mai Po Nature Reserve),
which found a low diversity of species overall, but with large numbers of a few
species (principally flying insects such as Chironomids) at certain periods,
notably during spring and autumn (Anon. 1993).
Fish
13.4.27
The fishponds are actively used
for the polyculture of freshwater fish, and therefore contain high densities of
various commercially stocked species (including Big Head Carp Aristichths nobilis, Grass Carp Ctenopharyngodon idellus, Common Carp Cyprinus carpio, Grey Mullet Mugil cephalus and Tilapia spp.). In addition high numbers of various
non-commercial species are likely to occur, including Mosquito Fish Gambusia patruelis.
Amphibians
13.4.28
Eight species of amphibians, a
third of the native Hong Kong amphibian fauna, have been recorded from
fishponds in the Deep
Bay area (Lau 1995).
However, predation of tadpoles by fish and the slightly saline water make the
fishponds at Fung Lok Wai unsuitable habitats for most amphibians and only
Guenther's frog Rana guentheri are known to breed in the ponds.
13.4.29
Five species of amphibian were
found off site at the nearby Tin Shui Wai Reserve Zone (Binnie Consultants Ltd 1997a). However, only Guenther’s frog and
Asiatic toad Bufo asiatica, both
common and widespread species, were recorded at Fung Lok Wai at this time.
Reptiles
13.4.30
In total 16 species of reptiles
have been recorded from the fishponds in the Deep Bay area including five
species of reptile of conservation importance which are known to occur within
the north-west New Territories, Chinese Soft-shelled Turtle Pelodiscus sinensis, Chinese
Three-keeled Pond Turtle Chinemys reevesii,
Burmese Python Python molurus,
Chinese Cobra (Naja atra) and
Copperhead Racer Elaphe radiata. Of
these Chinese Soft-shelled Turtle, Chinese Three-keeled Pond Turtle and Burmese
Python are protected under Schedule 2 of the Hong Kong SAR Wild Animals
Protection Ordinance. These three species are also recorded on the IUCN list of
globally threatened species. Chinese
Soft-shelled Turtle and Chinese Three-keeled Pond Turtle prefer reservoir and
pond habitats with soft sediments and so could occur within the habitats of
Fung Lok Wai, however the distribution of Chinese Soft-shelled turtle is
localised. Burmese Python is unlikely to utilise the fishpond habitats of the
Study Area preferring instead scrubby and mangrove habitats.
13.4.31
Although a comprehensive reptile
survey was not carried out at Fung Lok Wai as part of the original proposal,
the following species were recorded: Chinese water snake Enhydris chinensis (juvenile found under sacking on edge of pond 7)
and common rat snake Ptyas mucosus (discarded
skin found on bund between pond 21 & 22). In addition, checkered keelback
snake Xenochrophis piscator,
Bowring's gecko Hemidactylus bowringii,
many-banded krait Bungarus multicinctus,
common rat snake Ptyas mucosus and
three keeled pond turtle have been recorded nearby, and are therefore likely to
occur on site. In general the regular disturbance to aquaculture ponds
associated with the intensive fish farming at Fung Lok Wai is likely to limit
opportunities for reptile populations to become well established.
Birds
13.4.32
Of all species groups, birds
have been the subject of most studies and surveys of the fishponds of the Deep Bay
area. These include feeding studies by Melville (1987), Wong (1991), Britton
(1993) and Young (1993). Further ecological appraisals have been made on the
use of fishponds by birds by Melville et
al. (1994) and Chu (1995). A detailed
assessment of the use of fishponds by birds was completed as part of a Fish
Pond Study by the Planning Department in 1997 whose specific aim was to assess
the ecological value of fishponds within the Deep Bay
area.
13.4.33
Fish ponds are used by a wide
range of waterbirds, land birds associated with bund vegetation and birds
feeding aerially on insects above the water. These include a wide range of
raptors, waders, gulls, terns and passerines. Ponds are used by different
species at different times of the year, a large proportion of which occur in
high numbers in the Deep
Bay area. In fact the
similarity in the bird community composition at Mai Po Nature Reserve and
the fishponds suggests that they should be treated as an integrated unit
because birds regularly move between the two. Overall, it is understood that
the fishponds provide habitat for half the number of waterbirds found at Mai Po and 10% of the number of
the entire Deep Bay
area, though proportionately more egrets, herons and cormorants, use fishponds
than the other habitats within Deep
Bay (Aspinwall Clouston
and Wetlands International 1997).
13.4.34
Wintering bird data collected
by the Hong Kong Bird Watching Society (HKBWS) since 1979 indicate there has
been a significant increase in total waterfowl using the Deep Bay Area in Hong Kong (Carey et
al. 2001) and in total numbers of herons and egrets, ducks, waders and
cormorants (Aspinwall Clouston and Wetlands International 1997). However,
numbers at Mai Po
and Futian (on the northern shore of Deep Bay, in mainland China) have remained relatively
constant, suggesting that the current carrying capacity of these sites has been
reached.
13.4.35
The increase in herons and
egret populations in winter is due to birds using both Deep Bay
itself and the wider fish pond habitats throughout the bird count areas. This
increase in use is most likely due to a decrease in persecution of breeding
individuals, an increase in food supplies in the breeding and wintering period,
and the loss of habitats outside Deep
Bay.
13.4.36
Winter population increases in
ducks is most likely the result of increased prey biomass in the Deep Bay
mudflats, due to organic enrichment, increases in total flyway populations and
habitat loss elsewhere in the region. Similarly wader populations have probably
benefited from the organic enrichment of the mudflats, as well as an increased
provision of high tide roosts within Deep
Bay and associated
habitats at Mai Po.
Increased observer coverage may also account to some extent
for the increase in numbers counted.
13.4.37
Comprehensive surveys of the
birds occurring at the Fung Lok Wai site were undertaken between 2nd December
1993 and 27th November 1997. A total of 100 species of birds were recorded at
Fung Lok Wai over the course of the surveys. Although many of the birds
recorded do not visit the site regularly; at least 33 regularly occur,
including ubiquitous species like tree sparrow and Chinese Bulbul and those,
like Chinese Pond Heron, Little Egret and Common Kingfisher, which regularly
feed around ponds. Of the regular species, 19 (58%) could be reasonably
described as wetland birds including some of conservation importance, such as
Little Egret, Cattle Egret and Chinese Pond Heron. However, the number and
diversity of several waterbird groups such as Snipe, rails, crakes and reedbed
passerines appeared to be low, probably as a result of the intensive management
of fishponds and consequent lack of emergent vegetation.
13.4.38
A specific review of the
effects developments may have on egretry sites has been completed as a separate
report (AEC 2002). Evaluation of the current bird interest at the site is
described in section 13.5 below.
Mammals
13.4.39
Eleven mammal species have been
recorded from aquaculture ponds (fishponds that are actively managed, those
that are currently unmanaged, and the intervening bunds) and vegetation at the
nearby Mai Po
marshes (Ades et al. 1995). In particular the Chinese Otter which was
considered extinct in Hong Kong until its
rediscovery in 1990 at Mai Po.
A detailed survey of mammals occurring at Fung Lok Wai was
not undertaken during documented previous surveys and the only mammals noted
during site visits were brown rat Rattus
norvegicus and Japanese pipistrelle bat Pipistrellus
abramus. In addition, house shrew Suncus
murinus and house mouse Mus musculus
would also be expected to occur. Crab
eating mongoose Herpestes urva has
also been seen off site, in nearby mangrove and Melville (1991) has predicted
that small Indian civet Vivericula indica
and leopard cat Felis bengalensis
could occur at nearby Nam Sang Wai.
13.4.40
Documents associated with EIAs
prepared for previous development proposals in the Deep Bay Area were reviewed
but provided little additional information on mammalian fauna of the area. In
general though, the disturbance from the intensive fish pond management and
lack of vegetation cover at Fung Lok Wai is likely to make the site unsuitable
for most larger mammals.
Summary of Key Information Gaps
13.4.41
No habitat or species survey
data reviewed were found to be up to date, comprehensive or covering the
complete Assessment Area as required by the Study Brief. A comprehensive suite
of surveys were therefore proposed for all habitats, aquatic invertebrates,
terrestrial invertebrates known to have some association with the habitats
occurring at the site, wild freshwater fish, amphibians, reptiles, birds and
mammals.
13.4.42
The information gained from the
review of existing information above will be utilised along with the data
obtained from recent surveys to identify, predict and evaluate impacts and
formulate appropriate mitigation measures and monitoring for the site.
13.5.1
The field survey methodology
utilised for this EcIA follows the general principles outlined in Annex 16 of
the Technical Memorandum to the EIA Ordinance and aims to provide adequate and
accurate baseline survey information of the proposed development and its
vicinity, with respect to the ecological importance of flora, fauna and habitats
found. Section 6.8 of the Town Planning Board planning guidelines TPB PG-No.
12B (Town Planning Board 1999) stipulates that for development proposed within
or encroaching either the WBA or WCA, baseline surveys should be undertaken
over twelve consecutive months to establish the existing wildlife habitats and
flora and fauna present and any seasonal changes.
13.5.2
The baseline habitat and
ecological surveys for the study site commenced on the 10/1/2001
and were completed on 3/1/2002. The surveys were conducted by qualified,
professional ecologists with at least three years relevant expertise in
surveying their respective taxa groups in Hong Kong and South
China.
13.5.3
Since completion of the surveys
there has been no change in wetland area, there has been no in-filling of fish
ponds, for example. There has, however, been a change in management of fish
ponds. Site visits undertaken in recent years, including by WWF staff in
October 2006 and May 2008, indicate that relatively few ponds (about one
quarter) are now in active production (Janet Lee, Pers. Comm.). For abandoned ponds, grass
has encroached into the open water from the side of the ponds and Water
Hyacinth (Eichhornia crassipes) is
abundant in some cases. In the absence of active management, bunds have become covered
by long grass which reduces their attractiveness as roosting sites for
waterbirds.
13.5.4
As the extent of wetland has
not changed it is considered that the importance of the site for most species,
including birds that are not dependent on the active fishpond management (eg
Red-billed Starling) and non-avian fauna (such as reptiles) will be unchanged.
For those birds that are dependent on the active management of fish ponds
(including egrets and Black-faced Spoonbill) it is expected that the importance
of the site will have declined.
13.5.5
To determine whether there have
been changes within the wider north-west New Territories in the abundance of
key bird Species of Conservation Importance, an analysis of bird records within
the Deep Bay area has been undertaken (Appendix 13-12). This analysis includes
a comparison of recent records within a recording area that includes Fung Lok
Wai with data for the wider Deep
Bay area. It indicates
that there is no significant change in the importance of Fung Lok Wai for
Species of Conservation Importance since the conclusion of the baseline surveys
and that, for key species (egrets and Black-faced Spoonbill) there appears to
be a loss of value.
13.5.6
It is considered that the
results of these surveys remain applicable to the assessment. Any changes
taking in place in the intervening period involving a reduction in ecological
value due to a reduction in fish farming activity. There is evidence that this
had most effect on key bird species of interest such as egrets and Black-faced
Spoonbill that typically benefit most from aquaculture activities that
periodically provide access to food resources.
Habitats
13.5.7
Aerial photograph of the study
site supplied by the Lands Department (CN27931, 10/8/2000)
was used to delineate the boundaries of the different natural and artificial
habitats present within the Assessment Area.
The boundaries of each habitat type were transcribed onto a 1:5000
scaled map and ground-truthed on subsequent site visits. Representative colour
photographs were taken of each habitat. Wetland habitat types were classified
according to the ‘Ramsar Classification System for Wetlands’ (Appendix 13.1)
and terrestrial habitats were classified on the basis of the structural
characteristics of the dominant vegetation present. The completed habitat map
was digitised into MapInfo V.6.
13.5.8
The total area in hectares (ha)
and percentage coverage of each habitat type present within the Assessment Area
was calculated using a Lands Department digital topographic base map of the
site which was ground-truthed and geocoded.
Vegetation
13.5.10 Each habitat within the Assessment Area was inspected and a species
list and a semi-quantitative estimate of abundance recorded.
13.5.11 More detailed quantitative surveys to determine species composition
were undertaken within those habitats present within the Study Site during both
wet and dry seasons. Within each of these habitats, ten randomly distributed 1m2 fixed quadrats were surveyed.
Quadrat locations were permanently marked to enable resurvey and hence direct
comparison between seasons. The data were recorded as percentage cover of each
species identified within three growth layers. In addition, notes were made of:
·
Vegetation structure
·
Dominant plant species
·
Condition
·
Presence of any specific
features of ecological significance
13.5.12 Quadrat locations are identified in Figure 13‑3.
Invertebrates
Aquatic Invertebrates
13.5.13
The aquatic invertebrate
community was sampled at a total of nine locations across the site using a
combination of three survey techniques to enable all major aquatic biomes to be
sampled. Aquatic sampling locations are shown in Figure 13‑4.
13.5.14
Permanent watercourses were
surveyed using pond net and kick sampling during the wet season in August 2001
and repeated again during the dry season in December 2001, using the same
sampling locations in both seasons to gain a representative sample of the
aquatic invertebrate community during both periods.
13.5.15
Fishponds were surveyed using
pond net and benthic core sampling again during both the wet and dry seasons.
13.5.16
Pond net – Sweep net sampling
was conducted within the study site to assess the species composition and
abundance of aquatic species that inhabit the water column and cling to
submerged vegetation present in the permanent streams. A D-shaped sampling net 30 cm in diameter comprising 1 mm mesh was used. Each sample comprised two
2-metre sweeps of the net. The first
sweep was conducted through the mid water column, whilst the second sweep was
passed over the bed of the watercourse.
For each sample site the replicate samples were combined, preserved and
stored.
13.5.17
Three permanent watercourses
present within the study site were surveyed. Three random samples were being
taken at each sampling location.
13.5.18
Six fishponds were sampled
across the study site with five random samples being taken within each pond
along the water/bund interface. A larger sample size was used during the survey
of aquatic invertebrates in the fishponds, as these represent a significantly
larger area of the study site.
13.5.19
Kick net – Kick net sampling
was used to sample the macro-invertebrates that inhabit the soft substrate of
the streambed. A kick net of the
following dimensions: height = 0.25m,
width = 0.3m, length
= 0.5m and a mesh size of 1mm was used.
The flat base of the kick net was placed on the stream bed and held
securely. The open mouth of the net was placed facing upstream. A surveyor
kicked a 1m2 area of
substrate on the stream bed, directly upstream of the net, ten times to
dislodge macro-invertebrates inhabiting the sediment. Any invertebrates caught
in the net were removed and preserved in 70% alcohol for later identification.
13.5.20
In the laboratory each sample
was rinsed onto a 500 micron fine mesh sieve to remove sediment particles. The
washed samples were sorted into species groups. Specimens of target taxonomic
groups were identified to family level using a binocular microscope, and the
number and biomass (dry weight, including shell in the case of molluscs) of
each family represented was quantified. The target species groups include:
Coleoptera: beetles, Crustaceans: crabs, shrimps, Diptera: chironomids,
psychodids, Ephemeroptera: mayflies, Heteroptera: water bugs, Hirundinea:
leeches, Mollusca: shellfish, Tipulids: craneflies, Trichoptera: caddisflies.
Species for other taxa groups were recorded and counted, but not weighed. The
number and species of any fish incidentally captured during the sampling was
also recorded.
13.5.21
Two permanent watercourses were
sampled using kick netting. This method is inappropriate for sampling closed
waterbodies with no flow current, so a different method, benthic core sampling,
was used to survey the benthic invertebrate community within the fishponds.
13.5.22
Cylindrical benthic cores –
Benthic cores were taken from six fishponds within the study site to identify
the species composition and abundance of freshwater invertebrates that inhabit
the soft substrate along the shallow aquatic margins of the ponds. This
sampling method was used to assess the value of the current fishpond margins to
waterbirds. The fishponds were sampled
once during the wet season in August 2001 and resurveyed during the dry season
in December 2001.
13.5.23
Cylindrical benthic cores 10cm in diameter and 20cm in length were inserted into the
submerged sediment to a depth of 10cm,
rotated and gently removed. Six randomly
located replicate cores were collected from each pond.
13.5.24
The contents of each core were
immediately removed and preserved in 70% ethanol. Back in the laboratory each
core was washed on a 500 micron fine mesh sieve to remove all sediment
particles. Invertebrates were identified
to family level under a binocular microscope.
The number and biomass (dry weight, including shells in the case of
gastropods) of individuals in each target taxonomic group was quantified, as
for the kick-net sampling. Species from other taxa groups were recorded and
counted, but not weighed.
Dragonflies
13.5.25
Dragonflies were surveyed by a
suitable qualified ecologist along the set transect routes T1-T10 (Figure 13‑5). Dragonflies were surveyed twice per month during
May, June, September and October 2001, and once per month in April, July,
August and November 2001.
13.5.26
Each survey commenced at the
beginning of transect T1. The surveyor walked along the entire length of each
of the transects T1 to T10 in
sequential order at a uniform pace. All
butterflies and dragonflies identified in front of and within 5 metres either
the side of each transverse (but not behind) the surveyor were recorded. Where
feasible the number of male and female dragonflies observed were recorded for
each species. Where large swarms of dragonflies were encountered an estimate
was made of the approximate number of dragonflies present.
13.5.27
Counts were conducted between
10:00 and 16:00 hours during optimum weather conditions that comprise dry
weather with an air temperature of above 17oC in the shade, with at
least 50% sunshine and light wind conditions.
Butterflies
13.5.28
Butterflies were surveyed
concurrently with dragonflies, following the transect survey methodology and
schedule detailed above (refer to Figure
13‑5 for transect routes). The survey schedule takes
advantage of peak butterfly activity that occurs in Hong
Kong during May to
June and September to October.
Fish
13.5.29
The irrigation ditches present
within the study site were surveyed for fish during May 2001. The sampling
locations are shown in Figure
13‑6. A 1cm mesh net was placed across the narrowest
section of the drainage ditch. The
surveyor subsequently walked downstream with exaggerated movements to direct
the fish into the net. Fish disturbed were collected using hand nets and
identified on site.
13.5.30
Bankside observations were also
carried out at locations along the drainage ditch where the water was too deep
to carry out efficient sampling. This
survey method was also used in shallow, slow-flowing waters with limited
instream or backside vegetation where fish could easily be seen.
13.5.31
The species of fish and their
abundance were recorded. All individuals collected for identification were
released at the place of capture as soon as possible. Specimens for which
identification was uncertain were kept temporarily in fish tanks pending
taxonomic verification; once identified, the specimens were released at their
point of capture.
Amphibians
13.5.32
Amphibians were surveyed along
set transects T1 – T10 within the study site (Figure
13‑5). Monthly amphibian surveys were undertaken at dusk
over two consecutive days between April and October 2001. Incidental sightings
of amphibians were also recorded during the daytime surveys for insects and
reptiles.
13.5.33
Surveys were conducted for a
fixed period from 18:30 to 20:30. The surveyor used a torch light to scan the
aquaculture ponds, permanent streams, agriculture fields, reedbed, marsh and
pools, and vegetation therein to spot amphibians. Day light surveys that were conducted along
transects T1 to T10 to record reptile, butterflies and dragonflies were
conducted for a set time duration from 10:00 to 16:00hrs.
13.5.34
All amphibians recorded were
identified to species level, counted and where possible sexed.
Reptiles
13.5.35
Reptile surveys were undertaken
monthly between April and November 2001. The reptile population was surveyed
along the same transect route as that used for the dragonfly and butterfly
surveys (Figure
13‑5). Reptiles
were surveyed during daytime for a fixed time period of 10:00 – 16:00, during
warm sunny weather, which are the optimum climatic conditions for
reptiles. Opportunistic sightings of
reptiles were also recorded during the amphibian surveys conducted at the
site.
13.5.36
The surveyor walked along
transects at a standard pace and actively searched out reptiles in likely
basking spots and retreats (e.g. exposed sunny open patches of ground,
abandoned materials, habitat edges, or areas shaded from direct sunlight such
as under bushes or shrubs etc) and as far ahead along the transect as
possible. For each reptile seen, the
individual was identified to species level and the number of individuals
counted recorded for each transect. The surveyor used close focusing binoculars
to spot and identify reptiles to species level that were observed in the
distance.
Birds
Transect surveys
13.5.37
The Mai Po Inner Deep Bay
Ramsar Site is an important site for migrating and
wintering wetland dependent birds. Furthermore, aquaculture ponds are known to
be of considerable value as foraging habitat for birds, particularly when they
are drained down (Aspinwall, 1997). Consequently significant survey effort was
applied to surveying birds within the Assessment Area and a particular focus
was placed on gathering information about the usage of specific ponds by birds
throughout the year.
13.5.39 Transects T1-T5 which are located within wetland areas and transect
T6 which is located in the scrubland, agricultural land, orchard and grassland
located within the 500m buffer
zone adjacent to the southern part of the study site were surveyed on foot.
Transect T7, which encompasses a large area of habitats within the 500m buffer zone was surveyed from a slow
moving vehicle that made frequent stops to allow accurate counts to be made. To
coincide with peak bird activity, each survey was commenced one hour after
dawn.
Transects T1-T5 and T7
13.5.40 During surveys of these transects all birds were identified to
species and associated information, such as weather conditions, habitat type
and site condition were recorded on standard survey forms. Pond management practices and the status of
vegetation growing on the bunds were also recorded. The species
and abundance of birds observed flying over the study were also recorded if the
surveyor was certain that these individuals had not previously been recorded
during that particular visit.
13.5.41 Bird surveys were undertaken 2 to 3 times per month from January to
December 2001. Aspinwall (1997) identified that waterbirds congregate at
drained aquaculture ponds to feed on ‘trash fish’ exposed in shallow
water. To assess the species and
abundance of waterbirds that utilise drained ponds transects T1-T5 and T7 were
surveyed three times per month during those months when aquaculture ponds were
drained down (ie January, February, September, October and November). For the
remainder of the year (i.e. March to August) transects T1-T5 and T7 were
surveyed twice per month.
Transect 6
13.5.42
Surveys of Transect 6 were
particularly focused on passerine species associated with the complex mosaic of
habitats present within this southern part of the assessment area. In addition
to presence or absence of species, resident status in Hong
Kong was assigned according to the following categories (Carey et
al., 2001):
·
Breeding resident (R)
·
Passage migrant (M)
·
Spring migrant (SpM)
·
Summer breeding visitor (Su)
·
Autumn migrant (AM)
·
Winter visitor (W)
·
Possible winter visitor (?W)
Flight
line surveys
13.5.43
A survey of the flight lines of
birds over the Assessment Area was undertaken as a separate exercise during the
period January – December 2001. The
specific objectives of the study were to identify any likely adverse ecological
impacts that the proposed residential complex may have on bird flight paths,
particularly in relation to species of conservation importance within three key
groups of birds, listed below, and to identify any measures that could be taken
to minimise impact on these bird groups, particularly in relation to building
height and location. The key bird groups surveyed were:
·
“ardeids” – herons and egrets,
·
“raptors” – birds of prey,
·
“waterbirds” – ducks,
cormorants and spoonbills.
13.5.44
During the twelve month period
between January – December 2001, bird flight over the proposed development site
was surveyed twice a month by a
professional ornithologist from fixed vantage points situated
on a hillside north of Ng Uk Tsuen (Figure
13‑8). These vantage points were selected because they
provide an unobstructed view over the entire Study Site and surrounding area.
13.5.45
Bird flight activity is known
to be related to time of day so surveys were conducted during the periods
immediately after sunrise and immediately before sunset, when activity is
greatest and when there is sufficient light to allow identification. Morning
and evening surveys were conducted on separate days during each month.
13.5.46
The duration of each survey was
four (4) hours subdivided into eight (8) equal half-hour segments. A relative
system was employed for the timing of surveys to compensate for changes in the
time of sunrise and sunset through the seasons (see Table 13‑2).
Table 13‑2 Survey Time Segments for Bird Flight Line Surveys
|
Time period code
|
Time segments
|
|
Evening
|
|
|
1
|
Sunset minus 30-0 mins
|
|
2
|
Sunset minus 60-30 mins
|
|
3
|
Sunset minus 90-60 mins
|
|
4
|
Sunset minus 120-90 mins
|
|
5
|
Sunset minus 150-120 mins
|
|
6
|
Sunset minus 180-150 mins
|
|
7
|
Sunset minus 210-180 mins
|
|
8
|
Sunset minus 240-210 mins
|
|
Morning
|
|
|
9
|
Sunrise
plus 0-30 mins
|
|
10
|
Sunrise
plus 30-60 mins
|
|
11
|
Sunrise
plus 60-90 mins
|
|
12
|
Sunrise
plus 90-120 mins
|
|
13
|
Sunrise
plus 120-150 mins
|
|
14
|
Sunrise
plus 150-180 mins
|
|
15
|
Sunrise
plus 180-210 mins
|
|
16
|
Sunrise
plus 210-240 mins
|
13.5.47
During surveys all birds flying
over the site were identified to species level. The individual flight lines of
target species (defined in Table 13-3) were recorded on standard survey maps,
uniquely referenced, and the following information recorded on cross-referenced
data sheets:
·
Reference number
·
Survey date
·
Survey period
·
Species code
·
Number of birds in the group
(flocks of two or more birds often follow a similar route)
·
Approximate altitude estimated
by the observeer
Table 13‑3 Target
Species for Flightline Surveys and Their Species Codes used on Recording Sheets
|
Species
|
Species code
|
|
Ardeids
|
|
Cattle
Egret (Bubulcus ibis)
|
CE
|
|
Chinese
Pond Heron (Ardeola bacchus)
|
CPH
|
|
Great
Egret (Egretta alba)
|
GE
|
|
Grey
Heron (Arda cinerea)
|
GH
|
|
Little
Egret (Egretta garzetta)
|
LE
|
|
Black-crowned
Night Heron (Nycticorax nycticorax)
|
NH
|
|
Waterbirds
|
|
Black-faced
Spoonbill (Platalea minor)
|
BFS
|
|
Eurasian
Spoonbill (Platalea leucorodia)
|
ES
|
|
Great
Cormorant (Phalacrocorax carbo)
|
GC
|
|
Northern
Pintail (Anas acuta)
|
NP
|
|
Spot-billed
Duck (Anas poecilorhyncha)
|
SD
|
|
Raptors
|
|
Black
Kite (Milvus migrans)
|
BK
|
|
Common
Buzzard (Buteo buteo)
|
CB
|
|
Common
Kestrel (Falco tinnunculus)
|
CK
|
|
Crested
Serpent Eagle (Spilornis cheela)
|
CSE
|
|
Greater
Spotted Eagle (Aquila clanga)
|
GSE
|
|
Imperial
Eagle (Aquila heliaca)
|
IE
|
|
Osprey
(Pandion haliaetus)
|
OS
|
13.5.48
The observation locations are
approximately 40m
above ground level thus enabling the observer to gauge altitude. Nevertheless
it was not considered feasible to estimate altitude accurately to less than 20m and so height categories of 20m interval were employed (Table 13‑4Error! Reference source not found.).
Landmarks along the horizon were also used to estimate the height at which the
birds were flying across the Study Site.
Table
13‑4 Altitude Categories
Adopted to Record the Bird Flight Line Data
|
Altitude category
|
Altitude
|
|
1
|
<20m
|
|
2
|
20-40m
|
|
3
|
40-60m
|
|
4
|
>60m
|
13.5.49
The survey data were manually
geo-coded into a GIS (MapInfo Ver. 6) and the following attributes input for
each individual flightline:
·
Species
·
Altitude category (except for
data collected during January 2001)
·
Date and time period code
·
Number of birds in the
group
13.5.50
For analytical purposes, the
survey data were aggregated into months (Jan, February, March etc.).
13.5.51
Flight line data were geo-coded
and overlaid onto digitised base maps of the Study Site.
13.5.52
The GIS package was
interrogated to identify the species composition and abundance of birds flying
over any sector (or all) of the Study Site for any (or all) altitude categories
and for any (or all) months. On the basis of these data it was possible to
compare the species composition and abundance of birds flying through the
sector occupied by the Proposed Development Area and to compare these to
similar data for the entire study area or any other sector of the study area.
13.5.53
Specific analyses focused on a
describing the absolute and relative abundance of target species flying across,
within, into or out of the Study Site and, in particular, the specific sector
of the Study Site that would be occupied by the proposed residential development
Mammals
13.5.54
Mammals were surveyed
concurrently during reptile and amphibian surveys along the set transect routes
shown in Figure
13‑5.
13.5.55
Mammals were surveyed monthly
during the day and at dusk from April
to November. As they are elusive species any evidence of
their presence including the presence of scats, tracks and feeding were also
recorded. Relevant data of sightings of mammals were recorded on standard
survey forms.
Habitats
13.6.1
On the basis of the literature
review, interpretation of aerial photographs, site inspections and flora and
fauna surveys, the ecological resources and receivers that may be affected by
the development were identified. Amongst these the Valued Ecological Components
(VECs) (Treweek 1999), both habitats and Species of Conservation Importance,
have been determined following the guidelines for the evaluation of ecological
importance of habitats and species given in the Technical Memorandum on
Environmental Impact Assessment Process (EPD).
Introductory Overview of Broad Habitat
Types
13.6.2
The Study Site (as defined in
Section 13.1.2) is composed almost entirely
of aquaculture ponds (fishponds that are actively managed, those that are
currently unmanaged, and the intervening bunds). The 500m buffer zone around the Study Site contains a
greater variety of habitat types including, Feng Shui woodland, permanent
natural freshwater habitats and mangrove stands, although aquaculture ponds
remain the dominant habitat type.
13.6.3
Based on interpretation of
recent aerial photographs, existing data and site inspections 19 distinct
habitat types were categorised on the basis of their botanical composition and
physical and structural characteristics:
·
Intertidal forested wetlands –
mangrove stands
·
Permanent rivers, streams and
creeks – natural flowing freshwater habitats
·
Ditches and drainage channels –
artificial ditches, drainage channels and nullahs
·
Aquaculture pond – fishponds bound by vegetated bunds; some
managed for commercial aqua-culture production, others where no management
facilities were observed in the immediate vicinity of the pond
·
Reedbed
·
Permanent freshwater marsh and
pools – flooded areas comprising a mix of water‑dependent plants
·
Seasonally flooded agricultural
land – includes intensively managed wet agricultural land
·
Dry agricultural land –
agricultural land on which a range of food crops and flowers are cultivated
·
Inactive agricultural land –
fallow or abandoned agricultural land which is un‑managed and has been
invaded by herbaceous or shrubby vegetation
·
Orchard – patches of fruit
trees mainly found scattered among rural village areas
·
Fung-shui forest – forest found
around rural villages comprising native species or a mix of native species and
fruit trees
·
Semi-natural secondary woodland
– woodland formed from a mixture of planted and native species, moderately
disturbed by human activity
·
Plantation forest –
landscaping or ornamental plantations mainly found along roads and on cut-slopes
·
Grassland – habitats dominated
by grass and herbaceous species
·
Grassland-shrubland mosaic –
undisturbed areas with grassland comprising 80% of cover
·
Landscaped area – areas managed
intensively for landscape or amenity purposes
·
Works in progress
·
Wasteland – secondary
vegetative colonisation (mainly grasses and ruderals) on areas opened by human
activities (excluding those grown on inactive agricultural land)
·
Developed area – areas highly
developed with no visible vegetation cover except road-side weeds and includes
a wastewater treatment works and associated water storage area
13.6.4
The distribution of these
habitat types within the Assessment Area is illustrated in Figure 13‑9. Representative photographs of each habitat type are
included in Appendix 13-2. Their respective coverage within the different
sectors of the study area is quantified in Table
13‑5 below.
Table 13‑5 Extent of Habitat Types
within the Assessment Area (ha.)
|
Habitat
|
1. Proposed Development Area
|
2. Wetland Nature Reserve
|
3. Study site (1 + 2)
|
4. 500m buffer zone
|
5. Assessment Area (3 + 4)
|
|
Intertidal
forested wetlands
|
0
|
0
|
0
|
45.3
|
45.3
|
|
Permanent
rivers, streams and creeks
|
0
|
0
|
0
|
25.2
|
25.2
|
|
Ditches and
drainage channels
|
0
|
0.4
|
0.4
|
0.4
|
0.8
|
|
Aquaculture
pond
|
4.0
|
75.7
|
79.7
|
90.1
|
169.8
|
|
Reedbed
|
0
|
0
|
0
|
0.4
|
0.4
|
|
Permanent
freshwater marsh and pools
|
0
|
0
|
0
|
2.8
|
2.8
|
|
Seasonally
flooded (wet) agricultural land
|
0
|
0
|
0
|
1.7
|
1.7
|
|
Dry
agricultural land
|
0
|
0
|
0
|
0.2
|
0.2
|
|
Inactive
agricultural land
|
0
|
0
|
0
|
5.2
|
5.2
|
|
Orchard
|
0
|
0
|
0
|
1.4
|
1.4
|
|
Fung-shui woodland
|
0
|
0
|
0
|
1.3
|
1.3
|
|
Semi-natural secondary woodland
|
0
|
0
|
0
|
18.4
|
18.4
|
|
Plantation
woodland
|
0
|
0
|
0
|
3.0
|
3.0
|
|
Grassland
|
0
|
0
|
0
|
4.2
|
4.2
|
|
Grassland –
shrubland mosaic
|
0
|
0
|
0
|
20.5
|
20.5
|
|
Landscaped area
|
0
|
0
|
0
|
8.8
|
8.8
|
|
Works in
progress
|
0
|
0
|
0
|
37.1
|
37.1
|
|
Wasteland
|
0
|
0
|
0
|
13.5
|
13.5
|
|
Developed area
|
0
|
0
|
0
|
61.9
|
61.9
|
|
TOTAL
|
4.0
|
76.1
|
80.1
|
341.4
|
421.5
|
13.6.5
The Proposed Development Area
and the area of the proposed Wetland Nature Reserve are dominated by
Aquaculture Ponds. The bunds associated
with these ponds have an infrastructure associated with fishpond operation
(houses, sheds, power lines, unmade tracks, duck shelters etc.). There are also
a limited network of Ditches and Drainage Channels.
13.6.6
The habitats surrounding this
central core of fishponds (ie within the 500m Buffer Zone) are more diverse. In the southern
part of the Buffer Zone there is a mosaic of wet and dry agricultural land
(Seasonally Flooded Agricultural Land, Dry
Agricultural Land
and Inactive Agricultural Land)
interspersed with naturally regenerating Freshwater Marsh and Reedbed that is
functionally linked to the aquaculture ponds to the north. Also within this
southern area, particularly on higher ground, there are semi-natural habitats
of Grassland and Grassland-Shrubland Mosaic. Habitats dominated by woody
species include Plantation Woodland, Orchard and Fung-shui Woodland. The remainder of the southern part
of the buffer zone is occupied by highly disturbed habitats such as Wasteland
and Developed Area associated with residential and industrial land-uses.
13.6.7
The northern part of the 500m Buffer Zone is dominated by Aquaculture
Ponds, which beyond the limit of reclamation, give way to extensive Inter-Tidal
Forested Wetlands (mangroves) and beyond the Assessment Area boundary,
inter-tidal mudflat.
13.6.8
The eastern and western parts
of the Assessment Area are bounded by permanent watercourses (Permanent Rivers,
Streams and Creeks) which potentially provide opportunity for linkage to
habitats over a wider geographical area. This capacity is severely limited,
however, due to their highly degraded state.
13.6.9
Following the guidelines in
Appendix 8 of the Technical Memorandum on Environmental Impact Assessment Process
(EPD), the habitats of the Assessment Area are individually evaluated below
with specific reference to their conservation value.
Habitat Evaluations
Intertidal Forested Wetlands
13.6.10
The northern part of the
Assessment Area (500m
Buffer Zone) is marine in character and extensive mangroves have developed in
inter-tidal areas. Although patches of intertidal mudflat remain, the dominant
vegetation is mangroves and for the purposes of this assessment this habitat
has been considered collectively as mangrove. The ecological value of this
habitat is evaluated in Table
13‑6.
Table 13‑6 Ecological Evaluation Of
Intertidal Forested Wetlands
|
Criteria
|
Intertidal forested wetlands
|
|
Naturalness
|
This habitat comprises naturally
regenerating mangrove forest interspersed with uncolonised mudflat, mangroves
are expected to colonise remaining mud-flat areas in coming years
|
|
Size (ha)
|
Relatively large; 45.3ha within the Assessment Area, none
within the proposed Development Area or proposed WNR area
|
|
Diversity
|
Mangroves possess a diverse range of
micro-habitats and species
|
|
Rarity
|
Common feature of inter-tidal zones in Hong Kong
|
|
Re-creatability
|
Low re-creatability
|
|
Fragmentation
|
Not fragmented (probably expanding in
area)
|
|
Ecological linkage
|
Linked to other areas of mangroves in the
Deep Bay area
|
|
Potential value
|
Unlikely to achieve significantly greater
value
|
|
Nursery and breeding ground
|
High, breeding ground for many marine
invertebrate species
|
|
Age
|
Unknown
|
|
Abundance/ Richness of wildlife
|
High
|
|
Conclusion*
|
Moderate to high
|
* Low, moderate or of high ecological
value
Permanent Rivers, Streams
And Creeks
13.6.11
This habitat type is restricted
to two relatively large and very disturbed water courses. The Eastern main
Drainage Channel in the eastern part of the Assessment Area and Tai River
outfall in the west. The ecological value of these water courses is diminished
due to extensive modifications to their banks and the very poor quality of the
water flowing within them. The ecological value of this habitat is evaluated in
Table
13‑7.
Table 13‑7 Ecological Evaluation of Permanent Rivers,
Streams and Creeks
|
Criteria
|
Permanent rivers, streams and creeks
|
|
Naturalness
|
Highly disturbed: water quality is poor
and there have been extensive modifications to banks and riparian zone
|
|
Size (ha)
|
Approx. 25 ha. Within the Assessment Area, 0 ha within the Proposed Development Area
or proposed WNR area
|
|
Diversity
|
Considered low in both habitat and
species diversity
|
|
Rarity
|
This habitat is not considered to be rare
and no rare species were recorded
|
|
Re-creatability
|
Readily re-creatable
|
|
Fragmentation
|
Not fragmented
|
|
Ecological linkage
|
Although watercourses can act as
corridors for the dispersal of plant and animal species the ecological
linkage of this habitat is considered to be low because of its highly
modified and disturbed condition
|
|
Potential value
|
Could be higher subject to water quality
improvements. Potential value is limited, however, due to bank modifications
|
|
Nursery and breeding ground
|
Not considered significant
|
|
Age
|
No information but considered irrelevant
|
|
Abundance/ Richness of wildlife
|
Poor
|
|
Conclusion*
|
Low
|
* Low, moderate or of high ecological
value
Ditches and Drainage Channels
13.6.12
Four drainage ditches were
identified within the Assessment Area. Used for translocating water between
fishpond areas, these ditches have low intrinsic value for flora and fauna, but
do provide some linkage between habitats. The ecological value of this habitat
is evaluated in Table
13‑8.
Table 13‑8 Ecological Evaluation of Ditches and Drainage Channels
|
Criteria
|
Ditches
|
|
Naturalness
|
Artificial
habitat
|
|
Size (ha)
|
Approx. 0.8 ha. Within the Assessment Area, 0.4 ha within the Proposed Development
Area and proposed WNR area
|
|
Diversity
|
Considered low
in both habitat and species diversity
|
|
Rarity
|
This habitat is
not considered to be rare and no rare species were recorded
|
|
Re-creatability
|
Readily
re-creatable
|
|
Fragmentation
|
Not fragmented
|
|
Ecological
linkage
|
Very limited
but does provide some linkage between some ponds in the western part of the
proposed Wetland Nature Reserve and the Tai River
outfall.
|
|
Potential value
|
Could be higher
subject to water quality improvements
|
|
Nursery and
breeding ground
|
Not considered
significant
|
|
Age
|
No information
but considered irrelevant
|
|
Abundance/
Richness of wildlife
|
Poor
|
|
Conclusion*
|
Low
|
* Low, moderate or of high ecological
value
Aquaculture Ponds
13.6.13
The dominant land-use within the Assessment
Area is aquaculture. This area consists of a matrix of fishponds bounded by
vegetated bunds, which is considered in this assessment as a complex of
functionally related habitats. The man-made bunds link fishponds to one another
and to adjacent terrestrial habitats. Bunds are a disturbed habitat type but
provide roosting areas and refuge for some bird species that forage in fishponds.
Actively managed aquaculture ponds are of higher ecological value than
unmanaged aquaculture ponds because they support more abundant prey and
periodic draw-down allow birds to access prey.
Table 13‑9 Ecological Evaluation of Aquaculture Ponds
|
Criteria
|
Aquaculture
ponds
|
|
Naturalness
|
Man-made
habitat; Actively managed for fish production are the least natural but tend
to support a higher diversity and abundance of birds
|
|
Size
(ha)
|
169.8 ha in Assessment Area of which 79.7 ha is within the Study Site. Of
this 4 ha is found within
the Development Area.
Forms
part of an extensive, contiguous block of aquaculture ponds within the Fung
Lok Wai Assessment Area that is itself closely linked to fishpond areas in the
Deep Bay Area, including Mai Po;
Active
aquaculture is more dominant within the Assessment Area
|
|
Diversity
|
Low
habitat diversity but very high in terms of the diversity of wildlife
supported; Unmanaged ponds tend to support fewer individuals
|
|
Rarity
|
The
habitat itself is not rare but some of the species supported are rare locally
or globally, notably some avifauna
|
|
Re-creatability
|
Readily
re-creatable
|
|
Fragmentation
|
Not
fragmented
|
|
Ecological
linkage
|
Part of
the large contiguous area of fishpond habitat in the Deep Bay
area and serves similar function to those located at Mai Po Nature Reserve
|
|
Potential
value
|
High
ecological potential if managed to enhance wildlife use
|
|
Nursery
and breeding ground
|
Actively
managed ponds are a highly productive system that are particularly important
for the high densities of important food resources provided for birds during
draw-down for harvest periods.
Inactive
ponds tend to be less valuable than active, but they do provide an important
breeding/nursery ground for the prey of bird and other mammals, notably
Tilapia and chironomids;
Bunds
provide a breeding ground for some passerines and numerous terrestrial
invertebrates
|
|
Age
|
Probably
less than 40 years. This issue is, in any event, considered irrelevant to the
ecological value of this habitat type
|
|
Abundance/
Richness of wildlife
|
High
|
|
Conclusion*
|
High
|
* Low, moderate or of high ecological
value
Reedbed
13.6.14
Reedbed habitat is restricted
to a small area, probably an abandoned fishpond in the southern part of the
assessment area. The area is small and densely occupied by Phragmites. Whilst
this area may provide cover for some species (eg birds) its small size and
dense growth limits its overall value. Small stands of reeds associated with
ditches are considered under Ditches and drainage channel as they form part of
the characteristic vegetation of that habitat type (see Table 13‑10)
Table 13‑10 Ecological Evaluation of Reedbed
|
Criteria
|
Reedbed
|
|
Naturalness
|
This is naturally regenerating habitat
within an artificial fishpond
|
|
Size (ha)
|
Total of 0.4 ha within the Assessment Area in
several small blocks.
|
|
Diversity
|
Both species and habitat diversity are
considered low
|
|
Rarity
|
Neither the habitat nor the species found
are considered rare
|
|
Re-creatability
|
Highly re-creatable
|
|
Fragmentation
|
Highly fragmented, only one small area
recorded within the Assessment Area
|
|
Ecological linkage
|
Links ponds in the Fung Lok Wai Study
Site and wet habitats in the southern part of the Assessment Area.
|
|
Potential value
|
Moderate potential value - would be
higher if actively managed as wildlife habitat
|
|
Nursery and breeding ground
|
Part of the Fung Lok Wai wetland system
and probably providing habitat for breeding invertebrates that form the foods
source of larger animals such as birds and amphibians
|
|
Age
|
No information is available but the size
and density of reed growth (at the time of the survey) suggests that it was
more than 5 years old
|
|
Abundance/ Richness of wildlife
|
Low
|
|
Conclusion*
|
Low
|
* Low, moderate or of high ecological
value
Permanent Freshwater Marsh and Pools
13.6.15
Areas of marsh occur in the
southern part of the Assessment Area in close association with various
agricultural land-uses. It is likely that these areas of marsh have formed on
land previously used for aquaculture or wet agriculture (see Table 13‑11).
Table 13‑11 Ecological Evaluation of Permanent Freshwater Marsh and Pools
|
Criteria
|
Permanent
freshwater marsh and pools
|
|
Naturalness
|
The marsh community appears natural but
has probably developed on agricultural fields or ponds that have become
inactive
|
|
Size
(ha)
|
Total of 2.8 ha within the Assessment Area in
several small to moderate sized blocks
|
|
Diversity
|
Species and habitat diversity are
considered moderate and low respectively
|
|
Rarity
|
Neither the habitat nor the species found
are considered rare
|
|
Re-creatability
|
This habitat is readily re-creatable provided
land is available
|
|
Fragmentation
|
Fragmented
|
|
Ecological
linkage
|
Part of the wetland systems of the Fung
Lok Wai and the Deep
Bay area as a whole
|
|
Potential
value
|
Moderate potential value - would be
higher if actively managed as wildlife habitat
|
|
Nursery
and breeding ground
|
Likely to provide a nursery/breeding
ground for the invertebrates which serve as an important food item to
insectivorous fauna
|
|
Age
|
No information is available, but species
diversity and plant age (at the time of the survey) suggests that this marsh
was over 5 years old.
|
|
Abundance/
Richness of wildlife
|
Moderate
|
|
Conclusion*
|
Low to Moderate
|
* Low, moderate or of high ecological
value
Agricultural Land
13.6.16
Agricultural land is found
within the southern part of the Assessment Area within the 500m Buffer Zone. Various type of
agricultural land are present and these have been distinguished on the type and
intensity of management in Table
13‑12 - Table
13‑14.
Table 13‑12 Ecological Evaluation of Seasonally Flooded (wet) Agricultural
Land
|
Criteria
|
Wet
agriculture
|
|
Naturalness
|
Man-made habitat actively managed for
crop production
|
|
Size (ha)
|
Total of 1.7 ha within the Assessment Area in
several moderate sized blocks
|
|
Diversity
|
Habitat diversity is low but diverse
invertebrate and vertebrate fauna are supported
|
|
Rarity
|
The habitat type is not rare in Hong Kong, but is declining rapidly, with few large
areas remaining. A number of rare bird species are known to utilise this
habitat type as feeding/roosting sites, including Northern Hobby
|
|
Re-creatability
|
It is readily re-creatable provided that
land is available
|
|
Fragmentation
|
The areas of this habitat are slightly
fragmented but lie in close proximity in the southern part of the Assessment
Area
|
|
Ecological linkage
|
Forms part of a mosaic of wet and dry
land-uses in the southern part of the Assessment Area. Functionally linked to
the broader Fung Lok Wai area
|
|
Potential value
|
High potential if ecologically sensitive
management practices are retained or adopted
|
|
Nursery and breeding ground
|
Likely to provide a nursery/breeding
ground for the invertebrates which serve as an important food item to
insectivorous fauna
|
|
Age
|
No information is available and this
criteria is considered irrelevant to the ecological value of active wet
agricultural land
|
|
Abundance/ Richness of wildlife
|
Moderate
|
|
Conclusion*
|
Moderate
|
* Low, moderate or of high ecological
value
Table 13‑13 Ecological
Evaluation of Dry Agricultural Land
|
Criteria
|
Dry agricultural land
|
|
Naturalness
|
Man-made habitat actively management for
crop production
|
|
Size (ha)
|
Total of 0.2 ha within the Assessment Area in
several small blocks
|
|
Diversity
|
Low to moderate in habitat diversity and
species diversity due to the diversity of food crops planted.
|
|
Rarity
|
The habitat type is not rare in Hong Kong, but a number of rare birds are known to use
this type of habitat for feeding and/or roosting.
|
|
Re-creatability
|
Readily re-creatable provided that land
is available
|
|
Fragmentation
|
Highly fragmented
|
|
Ecological linkage
|
Forms part of a mosaic of wet and dry
land-uses in the southern part of the Assessment Area. Functionally linked to
the broader Fung Lok Wai area
|
|
Potential value
|
Dry agricultural land could be managed to
promote wildlife use by adopting management practices that enhance habitat
heterogeneity; however, this may conflict with commercially driven crop
production
|
|
Nursery and breeding ground
|
Likely to provide a nursery/breeding
ground for the invertebrates which serve as an important food item to
insectivorous fauna
|
|
Age
|
No information is available and this
criteria is considered irrelevant to the ecological value of active dry
agricultural land
|
|
Abundance/ Richness of wildlife
|
Low
|
|
Conclusion*
|
Low to Moderate
|
* Low, moderate or of high ecological
value
Table
13‑14 Ecological Evaluation of Inactive Agricultural Land
|
Criteria
|
Inactive
agricultural land
|
|
Naturalness
|
Man-made habitat
|
|
Size (ha)
|
Total of 5.2 ha within the Assessment Area in
several small to moderate sized blocks
|
|
Diversity
|
Habitat diversity is moderate but
supports diverse species
|
|
Rarity
|
The habitat type is not rare in Hong Kong, but a number of rare avifauna species have
been reported from these areas
|
|
Re-creatability
|
Readily re-creatable
|
|
Fragmentation
|
Highly fragmented
|
|
Ecological linkage
|
Forms part of a mosaic of wet and dry
land-uses in the southern part of the Assessment Area. Functionally linked to
the broader Fung Lok Wai area
|
|
Potential value
|
Abandoned agricultural land could be
managed to promote wildlife use by adopting management that aims to enhance
habitat heterogeneity
|
|
Nursery and breeding ground
|
Likely to provide a nursery/breeding
ground for the invertebrates which serve as an important food item to
insectivorous fauna
|
|
Age
|
No information is available
|
|
Abundance/ Richness of wildlife
|
Low
|
|
Conclusion*
|
Low to Moderate
|
* Low, moderate or of high ecological
value
Orchards
13.6.17
Orchards are found within the
southern part of the Assessment Area and comprise a variety of fruiting tree
species often planted in association with other native and introduced tree and
shrub species (see Table
13‑15).
Table 13‑15 Ecological Evaluation of Orchards
|
Criteria
|
Orchards
|
|
Naturalness
|
Man-made habitats
|
|
Size (ha)
|
Total of 1.4 ha within the Assessment Area in
several small to moderate sized blocks
|
|
Diversity
|
Both the habitat diversity and species
diversity are low
|
|
Rarity
|
Neither the habitat nor the species found
are rare
|
|
Re-creatability
|
This habitat type is readily re-creatable
|
|
Fragmentation
|
Heavily fragmented
|
|
Ecological linkage
|
May provide movement corridor for
wildlife using the surrounding area
|
|
Potential value
|
Poor in potential value as they are close
to settlements and subject to high levels of disturbance
|
|
Nursery and breeding ground
|
No wildlife of conservation importance is
expected
|
|
Age
|
Age varies depending on how recently
planted. Presence of mature tress suggests significant age in some cases
|
|
Abundance/ Richness of wildlife
|
Low
|
|
Conclusion*
|
Low
|
* Low, moderate or of high ecological
value
Fung Shui Woodland
13.6.18
A single Fung shui woodland has
been identified in the southern part of the Assessment Area. The occupation by
breeding egrets during the four seasons ecological survey had increased the
conservation value of this small woodland area, however, recent observation
indicates that this egretry is now abandoned (eg. Anon 2005) (see Table 13‑16).
Table 13‑16 Ecological Evaluation of Fung Shui Woodland
|
Criteria
|
Fung
shui Woodland
|
|
Naturalness
|
Natural habitat but typical modifications
by villagers limit value
|
|
Size (ha)
|
Total of 1.3 ha within the Assessment Area in a
small block
|
|
Diversity
|
Structurally simple and species poor
|
|
Rarity
|
Fung shui woodlands are common,
traditional feature of village areas in the New Territories.
This example is rare because during the baseline surveys it supported an
active egretry (now abandoned)
|
|
Re-creatability
|
Habitat characteristics are difficult to
recreate
|
|
Fragmentation
|
Small isolated example although linked to
other habitats
|
|
Ecological linkage
|
Connected to other woody habitats and
adjacent to aquaculture ponds where ardeid species forage
|
|
Potential value
|
Limited due to village development in the
surrounding area
|
|
Nursery and breeding ground
|
Breeding egrets
|
|
Age
|
The size of the trees indicates an age of
over 50 years
|
|
Abundance/ Richness of wildlife
|
Low-Moderate
|
|
Conclusion*
|
With Egretry this habitats has High
Ecological Value without the Egretry its value is considered to be of Low to
Moderate Ecological Value
|
* Low, moderate or of high ecological
value
Semi-natural Secondary Woodland
13.6.19
Secondary woodland areas are
concentrated on the lower hillsides in the southern part of the Assessment
Area. These areas are semi-natural and fragmented (see Table 13‑17).
Table 13‑17 Ecological Evaluation of Semi-natural Secondary Woodland
|
Criteria
|
Semi-natural secondary woodland
|
|
Naturalness
|
Semi-natural
but with some modification and planting of non-native species
|
|
Size
(ha)
|
Total
of 18.4 ha within the
Assessment Area in several moderate sized blocks
|
|
Diversity
|
Low in
habitat diversity, moderate in species diversity
|
|
Rarity
|
Neither
the habitat nor associated species are rare
|
|
Re-creatability
|
This
habitat type is readily re-creatable
|
|
Fragmentation
|
Slightly
fragmented
|
|
Ecological
linkage
|
May
provide movement corridors for wildlife
|
|
Potential
value
|
High,
if disturbance factors were removed.
|
|
Nursery
and breeding ground
|
No
wildlife of conservation importance
|
|
Age
|
Young
to moderate
|
|
Abundance/
Richness of wildlife
|
Low to
moderate
|
|
Conclusion*
|
Low to
moderate
|
* Low, moderate or of high ecological
value
Plantation woodland
13.6.20
Two small areas of plantation
woodland were recorded within the Assessment Area, both are dominated buy
non-native and exotic species (Table
13‑18).
Table 13‑18 Ecological Evaluation of Plantation
Woodland
|
Criteria
|
Plantation woodland
|
|
Naturalness
|
Planted with predominantly non-native and
exotic species
|
|
Size
(ha)
|
Total of 3.0 ha within the Assessment Area in several small
to moderate sized blocks
|
|
Diversity
|
Low in habitat diversity, moderate in
species diversity
|
|
Rarity
|
Neither the habitat nor associated
species are rare
|
|
Re-creatability
|
This habitat type is readily re-creatable
|
|
Fragmentation
|
Not fragmented
|
|
Ecological
linkage
|
Low
|
|
Potential
value
|
Low due to non-native species planted but
succession could increase value
|
|
Nursery
and breeding ground
|
No wildlife of conservation importance
|
|
Age
|
Young to moderate
|
|
Abundance/
Richness of wildlife
|
Low to moderate
|
|
Conclusion*
|
Low
|
Grassland
13.6.21
Small pockets of grassland were
recorded across the Assessment site, primarily adjacent to the closed area
boundary road (Table
13‑19).
Table 13‑19 Ecological Evaluation of Grassland
|
Criteria
|
Grassland
|
|
Naturalness
|
Natural regeneration, probably on
disturbed areas. Subject to ongoing disturbance, including fire
|
|
Size
(ha)
|
Total of 4.2 ha within the Assessment Area in
several small blocks
|
|
Diversity
|
Low habitat and species diversity
|
|
Rarity
|
Neither habitat nor species recorded are
rare
|
|
Re-creatability
|
Highly re-creatable
|
|
Fragmentation
|
Highly fragmented
|
|
Ecological
linkage
|
Serves limited function as a link between
other habitats, however, proximity to developed and disturbed habitats limits
this function
|
|
Potential
value
|
Low due to ongoing disturbance effects
|
|
Nursery
and breeding ground
|
May contribute to invertebrate food
resource for larger animals of the Assessment Area
|
|
Age
|
Not known but likely to be recent
regeneration on previously disturbed land
|
|
Abundance/
Richness of wildlife
|
Low
|
|
Conclusion*
|
Low
|
* Low, moderate or of high ecological
value
Grassland-shrubland mosaic
13.6.22
Grassland-shrubland mosaic
habitat is associated with the hills in the southern part of the Assessment
Area. Although it forms a linked habitat with areas of woody habitat, this
habitat is subject to occasional burning through hill fires and hence its
diversity and value are limited (Table 13‑20).
Table 13‑20 Ecological Evaluation of
Grassland-Shrubland Mosaic
|
Criteria
|
Grassland-shrubland
mosaic
|
|
Naturalness
|
Natural habitat but subject to hill-fire
|
|
Size
(ha)
|
Total of 20.5 ha within the Assessment Area in
several moderately sized blocks
|
|
Diversity
|
Low habitat and species diversity is
found in this habitat
|
|
Rarity
|
Neither the habitat nor the species known
to be present are considered rare
|
|
Re-creatability
|
Readily re-creatability
|
|
Fragmentation
|
Not fragmented within the Assessment Area
|
|
Ecological
linkage
|
Linked to other woody habitats within the
Assessment Area and may provide cover for animal movements
|
|
Potential
value
|
Moderate ecological potential if
hill-fires can be controlled
|
|
Nursery
and breeding ground
|
None known
|
|
Age
|
Unknown. Fire disturbance tends to
maintain the habitat in early successional stages and prevents establishment
of woodland
|
|
Abundance/
Richness of wildlife
|
Poor
|
|
Conclusion*
|
Low
|
* Low, moderate or of high ecological
value
Landscaped area
13.6.23
The main section of landscaped
vegetation occurs in the eastern part of the Assessment Area adjacent to the
closed area boundary road. The major vegetation associated with this habitat is
intensively managed grass turf (Table
13‑21).
Table 13‑21 Ecological Evaluation of Landscaped Area
|
Criteria
|
Landscaped area
|
|
Naturalness
|
Man made and intensively managed
|
|
Size (ha)
|
Total of 8.8 ha within in the Assessment Area
in a relatively large block
|
|
Diversity
|
Very low
|
|
Rarity
|
No rare habitats or species
|
|
Re-creatability
|
Highly re-creatable
|
|
Fragmentation
|
Not fragmented
|
|
Ecological linkage
|
Creates a barrier between the wetland
habitats of the Assessment Area and the potential corridor of the Eastern
Drainage Channel
|
|
Potential value
|
None
|
|
Nursery and breeding ground
|
None known
|
|
Age
|
Young, created during the drainage works
conducted on the Eastern Main Drainage Channel.
|
|
Abundance/ Richness of wildlife
|
Very low
|
|
Conclusion*
|
Low
|
* Low, moderate or of high ecological
value
Wasteland habitats
13.6.24
Several categories of land that
has been highly disturbed including areas of wasteland and where ponds have
been in-filled. Due to the nature of the disturbance, including clearance and
compaction, vegetation may be absent or in the form of poorly developed
communities dominated by ruderal species (Table 13‑22).
Table 13‑22 Ecological Evaluation of
Wasteland Habitats
|
Criteria
|
Wasteland
|
Aquaculture
ponds (infilled)
|
|
Naturalness
|
This
is a man made
habitat with little or no intrinsic ecological value
|
This
is a man made
habitat with little or no intrinsic ecological value
|
|
Size
(ha)
|
Moderate;
13.5 ha
|
Small
|
|
Diversity
|
Not
relevant
|
Not
relevant
|
|
Rarity
|
Not
relevant
|
Not
relevant
|
|
Re-creatability
|
Readily
re-creatable
|
Readily
re-creatable
|
|
Fragmentation
|
Not
relevant
|
Not
relevant
|
|
Ecological
linkage
|
Not
relevant
|
Not
relevant
|
|
Potential
value
|
None
|
None
|
|
Nursery
and breeding ground
|
Not
considered significant
|
Not
considered significant
|
|
Age
|
No
information but considered irrelevant
|
No
information but considered irrelevant
|
|
Abundance/
Richness of wildlife
|
Poor
|
Poor
|
|
Conclusion*
|
Low
|
Low
|
* Low, moderate or of high ecological
value
Recreated
Wetland (Hong Kong
Wetland Park)
13.6.25
During the assessment period
there was an area of land in the western part of the assessment area that
was identified as Recreated Wetland. This area comprises wetlands and other
habitats forming part of the Hong
Kong Wetland Park. The Hong Kong Wetland
Park is a man-made wetland consisting of 60 hectares of re-created
habitats specially designed for waterfowls and other wildlife. Located on the western side of the Assessment
Area, the Wetland
Park was originally
intended to be an ecological mitigation area (EMA) to compensate for the
wetlands lost due to Tin Shui Wai New Town development. The original EMA has
now been expanded to become a conservation, education and tourism facility. During
the assessment period these habitats were under construction, followed by a
period of establishment, and their ecological value was, therefore, at the time
of the baseline surveys considered to be low. The works have now been completed
and the site has been in operation since May 2006. The value of the wetland
habitats at the Wetland
Park will increase with
time and it is anticipated they will become High in the lifetime of the Fung
Lok Wai project. As indicated in Table 13‑23 these habitats have been evaluated as Moderate –
High.
Table 13‑23 Ecological Evaluation of
Recreated Wetland
|
Criteria
|
Hong Kong Wetland
Park
|
|
Naturalness
|
Man made natural habitat, subject to human
disturbance through tourism
|
|
Size
(ha)
|
60 ha Wetland area, 1 ha Visitor Centre
|
|
Diversity
|
High
|
|
Rarity
|
High
|
|
Re-creatability
|
Re-creatable
|
|
Fragmentation
|
Not fragmented
|
|
Ecological
linkage
|
Potentially high as this area is close to
the proposed Fung Lok Wai WNR
|
|
Potential
value
|
High
|
|
Nursery
and breeding ground
|
Not significant record
|
|
Age
|
Young
|
|
Abundance/
Richness of wildlife
|
High
|
|
Conclusion*
|
Moderate - High
|
* Low, moderate or of high ecological
value
Developed areas
13.6.26
The southern part of the
Assessment Area includes a variety of heavily developed land-uses, including
Proposed Development Areas, and industrial estate, wastewater treatment and water
storage areas. Typically these have very low intrinsic ecological value. Those
species that do occur tend to be very common, introduced species or pests (Table 13‑24).
Table 13‑24 Ecological Evaluation of Developed Areas
|
Criteria
|
Developed
area
|
Wastewater
treatment area
|
Water
storage area
|
|
Naturalness
|
This
is a man made
habitat with little or no intrinsic ecological value
|
This
is a man made
habitat with little or no intrinsic ecological value
|
This
is a man made
habitat with little or no intrinsic ecological value
|
|
Size (ha)
|
Large
|
Moderate
|
Small
|
|
Diversity
|
Not
relevant
|
Not
relevant
|
Not
relevant
|
|
Rarity
|
Not
relevant
|
Not
relevant
|
Not
relevant
|
|
Re-creatability
|
Readily
re-creatable
|
Readily
re-creatable
|
Readily
re-creatable
|
|
Fragmentation
|
Not
relevant
|
Not
relevant
|
Not
relevant
|
|
Ecological linkage
|
Not
relevant
|
Not
relevant
|
Not
relevant
|
|
Potential value
|
None
|
None
|
None
|
|
Nursery and breeding ground
|
Not
considered significant
|
Not
considered significant
|
Not
considered significant
|
|
Age
|
No
information but considered irrelevant
|
No
information but considered irrelevant
|
No
information but considered irrelevant
|
|
Abundance/ Richness of wildlife
|
Poor
|
Poor
|
Poor
|
|
Conclusion*
|
Low
|
Low
|
Low
|
* Low, moderate or of high ecological
value
Conclusions
13.6.27
The outcomes of the individual
habitat evaluations are summarised in Table
13‑25. It can be seen that the most valuable habitat
components of the Assessment Area are wetland habitats. In particular the
extensive block of Aquaculture Ponds (fishponds that are actively managed,
those that are currently unmanaged, and the intervening bunds) that form a
large contiguous area embedded within the broader Deep Bay Area that
includes Mai Po.
Adjacent to this central fish pond area there is, in the
southern part of the Assessment Area, a mosaic of other wetland habitats
including wet agriculture, marshland and reedbeds. Whilst these areas are of
less intrinsic ecological value, their close proximity and functional linkage
with the main fish pond area enhances their overall status.
13.6.28
The egretry in the small
Fung-shui Woodland also in the southern part of
the Assessment Area was also a feature of high ecological value due to the
scarcity of active egretries in the New
Territories. However,
recent evidence suggests that it is abandoned (see Anon 2005); it
is of a low to moderate ecological value.
13.6.29
The key ecological value of the
Assessment Area is, therefore, the habitat it provides for breeding and
foraging birds, particular wetland birds such as herons and egrets. Traditional
aquaculture and agricultural management practices have, to a large extent,
engendered this value. At the same time, however, these practices also limit
the potential value of these habitats. Aquaculture ponds are for example small
and steep sided which restricts bird access and pond bunds are cleared to
maintain access to ponds. With more sympathetic management the value of the
wetland habitats at Fung Lok Wai could be significantly higher.
13.6.30
The extensive area of
inter-tidal habitat in the northern part of the Assessment Area is also of
moderate to high ecological value due to the high biological diversity of
mangal systems. There is no direct link between these habitats and the Proposed
Development Area, however, and the potential for impact is very low.
13.6.31
All other habitats within the
Assessment Area are considered to have low ecological value due, primarily to
previous and current levels of disturbance.
Table 13‑25 Summary of habitat evaluations in order of ecological value.
|
Habitat
|
Overall evaluation
|
|
Aquaculture
ponds
|
High
|
|
Fung-shui
woodland
With egretry
Without egretry
|
High
Low
to Moderate
|
|
Recreated
Wetland (Hong Kong
Wetland Park)
Intertidal
forested wetlands
|
Moderate
to high
Moderate
to high
|
|
Agricultural
land
Seasonally flooded
agricultural land
Dry agricultural land
Inactive agricultural land
|
Moderate
Low
to moderate
Low
to moderate
|
|
Permanent
freshwater marsh and pools
|
Low
to moderate
|
|
Semi-natural
secondary woodland
|
Low
to moderate
|
|
Permanent
rivers, streams and creeks
|
Low
|
|
Reedbed
|
Low
|
|
Ditches
and drainage channels
|
Low
|
|
Wasteland
Wasteland
Aquaculture ponds (infilled)
|
Low
Low
|
|
Grassland
|
Low
|
|
Grassland-shrubland
mosaic
|
Low
|
|
Orchard
|
Low
|
|
Plantation forest
|
Low
|
|
Landscaped
area
|
Low
|
|
Developed
areas
Developed area
Wastewater treatment area
Water storage area
|
Low
Low
Low
|
Species of Conservation Importance
13.6.32
Following guidance given in
Annex 16 (Note 3) of the EPD's Technical Memorandum on Environmental Impact
Assessment, species have been identified that are considered to be Species of
Conservation Importance. These are defined as species that occurred within the
Study Site in significant numbers and are:
·
Globally threatened (IUCN 2000,
Collar et al. 1994) or threatened in China (Endangered Species
Scientific Commission 1998).
·
Internationally Protected
Species, i.e. protected by international conventions: (1) The Convention on the
Conservation of Migratory Species of Wild Animals (the Bonn Convention), (2)
listed under an agreement between the Government of Australia and the
Government of the People’s Republic of China for the Protection of Migratory
Birds and their Environment, (3) listed under an agreement on the Protection of
Migratory Birds and their Habitats between the Government of Japan and the
Government of the People’s Republic of China.
·
Protected by Hong Kong
legislation and guidelines: (1) The Forests and Countryside Ordinance (Cap. 96),
(2) The Forestry Regulations (subsidiary legislation of Cap. 96), (3) The Wild
Animals Protection Ordinance (Cap. 170), (4) Protection of Endangered Species
of Endangered Species of Animals and Plants Ordinance (Cap. 586), (5) The
Fisheries Protection Ordinance (Cap. 171), (6) The Fisheries Protection
Regulations (subsidiary legislation of Cap. 171).
·
Protected by Chinese laws and
regulations: (1) The Wildlife Protection Law of the PRC, (2) The Wildlife
Protection Implementation Regulation of the PRC.
·
Note: All birds and bats are
listed in the Wild Animals Protection Ordinance primarily as protection from
hunting, persecution and trade etc. Therefore, only those that meet other
criteria listed here or are Locally Important Species according to criteria listed
below are considered to be Species of Conservation Importance.
·
Endemic to Hong Kong or south
China; if they are rare in the territory or have special conservation
importance according to other scientific studies, e.g. for birds if they are of
international importance (i.e. >1% of the biogeographical population) or
regional importance (as listed in the Deep Bay Ramsar Conservation Strategy
(Aspinwall Clouston & Wetlands International - Asia Pacific, 1997).
·
Based on the above criteria and
Fellowes et al. (2002), species that occurred within the Assessment Area identified as
being of conservation importance are further subdivided into categories of
global, regional or local conservation importance. Although these species
include some that are reasonably widespread in Hong Kong
they are considered important in sustaining the long-term biodiversity of the
territory.
Plants
13.6.33
For each habitat type surveys
were conducted to determine species composition and relative abundance. The
results of these surveys are included in Appendix 13-3.
A total of 326 plant species were recorded
within all habitats of the assessment area. Off these 206 are native to Hong
Kong, and most are common and widespread. No plant Species of
Conservation Importance were recorded in significant numbers at the site. However, four plant species of conservation
interest were recorded, within five different habitats (Table 13‑26).
Table
13‑26 Plant Species of Potential Conservation Interest Recorded within the Assessment Area
|
Plant species
|
Status within Hong Kong1
|
Regional distribution and
protected status
|
Recorded abundance
|
Habitat
|
|
Ammannia auriculata
|
Very rare
|
Regionally widespread
|
Occasional
|
Watercourse
|
|
Aquilaria sinensis
|
Common
|
Class 2 in China
|
Occasional
|
Woodland and orchard
|
|
Phymatodes scolopendria*
|
Rare
|
|
Scarce
|
Aquaculture Pond (bunds)
|
|
Sphenoclea zeylanica
|
Rare
|
|
Scarce
|
Wet Agriculture
|
1
Based on Corlett et al. (2000).
* Previously Microsorium scolopendrium
13.6.34
None of these species is common
within the assessment
area, with two (Phymatodes
scolopendria and Sphenoclea zeylanica)
recorded only from single specimens. Ammannia
auriculata is locally rare but regionally widespread in south China
and a known pan-tropical weed. It was located within Ditches and drainage channels habitat which is typical habitat for
this species. Aquilaria sinensis is
protected (Category III) in China
and listed as VU on IUCN red data list. It is, however, a common tree in Hong Kong where its natural status is difficult to
determine as it is widely cultivated. Phymatodes
scolopendria is usually a species of rocky shores. At Fung Lok Wai it was
recorded at the edge of a pond which was no longer actively managed and is
likely to be a remnant of previously cultivated plants. Sphenoclea zeylanica is rare in Hong Kong
and typically found in abandoned paddy fields and wasteland. Within this survey
it was located in a wet agricultural area in the southern part of the
Assessment Area outside the Proposed Development Area.
13.6.35
None of the above species are
protected under Hong Kong legislation. Only one Aquilaria
sinensis could be considered a species of Conservation Importance under the
criteria outlined in the EIAO –TM. However, this species is common in Hong Kong and likely to be a cultivated variety.
Aquatic Invertebrates
13.6.36
Surveys of aquatic
invertebrates reveal a highly depauperate fauna (Appendix 13-4). Commonly
sampled aquatic invertebrates include Dipteran species such as the ubiquitous
Chironominae spp. and crustaceans such as Palaemonid shrimps. Infrequent
gastropods were also sampled, particularly in watercourses. The dominant
species are typical of disturbed aquatic habitats, such as fishponds and
drainage ditches.
13.6.37
The absence of water of high
quality and the lack of flowing habitats clearly limits the value of the site
for aquatic invertebrates. Although diversity is low, the abundance of
Chironomids and Palaemonid shrimps is significant, however, because they form a
valuable source of food for other fauna, particularly birds.
13.6.38
Analysis of the variance of
sampled populations (sweep and core) of these groups throughout the site and
during wet and dry seasons, indicates that although there is significant
variability between locations, these invertebrates collectively provide a
reliable food source around the year.
Odonata
13.6.39
Twenty-six species of
dragonflies and damselflies were recorded during surveys within the Fung Lok
Wai EIA Assessment Area (see Appendix 13-5), approximately 23% of the known
dragonfly fauna of Hong Kong (Wilson
1997). These species are all common and widespread. Two species previously
considered to be of Local Conservation Concern (Fellowes et al. 2002), Potamarcha congener and Urothemis signata signata, are known to
be widespread in Hong Kong (Wilson et al. 2004).
13.6.40
Brachythemis contaminata, Ischnura senegalensis, Orthetrum sabina sabina, Pantala flavescens and Rhyothemis variegata aria are the most
frequently recorded species collectively accounting for over 60% of all
dragonflies recorded during the surveys.
13.6.41
Potamarcha congeneri was recorded on
only one occasion in the vicinity of the access track (Transect 3) in the
western part of the Buffer Zone. Urothemis
signata signata was recorded regularly along Transect 1 and less frequently
along Transect 6 and on a single occasion along Transect 2. Records of these
species accounted for only 1.2% of all dragonflies and damselflies recorded
during the surveys.
13.6.42
Whilst dragonflies and
damselflies are common throughout the Assessment Area, analysis of the transect
surveys indicate that the highest species richness is recorded in the southern
part of the site, within the Buffer Zone, where there is greater diversity of
habitats including wetland habitats.
13.6.43
Overall species diversity for
this group is limited. Regular surveys carried out throughout the year revealed
a fauna that is dominated by a few, common species.
Butterflies
13.6.44
Fifty-eight species of
butterfly were recorded within the Assessment Area, see Appendix 13-6. The
majority of these are common and widespread although, nine species are
considered to be uncommon, including Ampittia
dioscorides, Eurema laeta, Graphium doson, Heliophorus epicles, Polyura
athamas, Udaspes folus, Junonia orithya, Eurema brigitta and Hypolimnas
misippus.
13.6.45
Of these species Eurema brigitta and Hypolimnas misippus are considered to be of local concern on the
grounds that they are only known from 16 or less localities within Hong Kong (Fellowes et
al. 2002). However no species recorded at the site are protected under Hong
Kong SAR legislation nor are they considered to be Species of Conservation
Importance according to the criteria stated in Annex 16 of the EPD's Technical
Memorandum on Environmental Impact Assessment.
13.6.46
Analysis of the transect data
indicates that whilst butterfly species were recorded throughout the site,
species richness was greatest in the southern part of the Assessment Area,
within the Buffer Zone where there is more diversity of both wet and dry
habitats. Both species of local concern were recorded rarely with only 3
individuals of Eurema brigitta
recorded along Transect 3 and a single individual of Hypolimnas misippus recorded along Transect 4.
13.6.47
The value of the Assessment
Area for this fauna group is limited due to the limited range and extent of
terrestrial habitats within the Assessment Area. The species present are
largely common species that feed (in larval and adult stages) on the common and
depauperate flora that typifies the disturbed habitats of much of the site.
Species richness is greater in the southern part of the Assessment Area because
of the presence of a greater range of habitats and hence food plants.
Disturbance and unsympathetic management, however, still limit the value of
these areas for terrestrial invertebrate fauna, including butterflies.
Fish
13.6.48
During the course of this
survey five species of freshwater fishes, including two native species and
three alien species were recorded (see Appendix 13-7). The species recorded
were Carassius auratus (Goldfish), Monopterus albus (Oriental swamp eel), Gambusia affinis (Mosquito fish), Oreochromis niloticus (Nile Tilapia) and
Channa striata (Striped
snakehead). In addition to the species
found during this survey, Clarias
gariepinus, the introduced African catfish is known from similar areas with
disturbed habitats in the northern New
Territories, and is
likely to be found in the ditches and ponds of FLW. This is an alien species of
no conservation value.
13.6.49
Carassius auratus is native to Hong Kong and uncommon. All individuals seen during the
survey were dead specimens, probably discarded by fish farmers. Monopterus albus is a lowland species
favouring slow-flowing streams and wet agricultural areas. Although still
widespread, this species is on the decline due to the destruction of suitable
habitat in rural areas of the New
Territories (Chong and
Dudgeon 1992). As all individuals seen were young, breeding is confirmed in the
study area. Gambusia affinis is an
alien species of no conservation value that it is widespread and common in Hong Kong. Individuals seen included young of the year,
and breeding is thus confirmed in the study area. Oreochromis niloticus is an alien species of no conservation value.
Individuals seen included shoals of young of the year, and breeding is thus confirmed
in the study area. Channa striata is
an alien species known to have recently established in Hong
Kong (Cheung 1999). All specimens seen were fry or young fish
indicating the species is breeding in this drainage system. It is widespread
and common in the northern New
Territories, especially
the northwest. This species is a fierce invasive predator and is of no
conservation value.
13.6.50
All waterways sampled were
polluted and many were disturbed and/or choked with aquatic plants (such as the
exotic and highly invasive Water Hyacinth (Eichhornia crassipes)), which
clearly limits the diversity of lowland freshwater fish.
13.6.51
Most species found or expected
to occur are alien species. No fish species of conservation value were found
during the study period and although surveying in highly turbid waters limits
fish detection, none are expected. Although Monopterus
albus, a species thought to be in decline in Hong Kong
(Chong and Dudgeon 1992), is of some interest it is not considered to be a
Species of Conservation Importance.
Amphibians
13.6.52
Eight species of frog were
recorded during the surveys of the Assessment Area (see Appendix 13-8). With
the exception of Two-Striped Grass Frog (Rana taipehensis), these are all
common species that are widespread within Hong Kong.
Two-Striped Grass Frog has a limited distribution in the New
Territories and as it is known from 16
or less locations in Hong Kong it is
considered to be of local conservation concern by Fellowes et al. (2002). However no amphibian species recorded at the site are protected
under Hong Kong SAR legislation nor are they considered to be Species of
Conservation Importance according the criteria stated in Annex 16 of the EPD's
Technical Memorandum on Environmental Impact Assessment.
13.6.53
Although frogs were recorded throughout the
site, Transect 1 in the
southern part of the Assessment Area, within the Buffer Zone, yielded the most
species richness and individual abundance. This transect was the only location
where Two-Striped Grass Frog was recorded.
Reptiles
13.6.54
Twelve species of reptiles were
recorded during the surveys of the Assessment Area, including five species of
lizards and seven species of snake (see Appendix 13-9). The lizard species
recorded are all widespread within Hong Kong,
however, all the snakes, with the exception of Checkered Keelback and
White-spotted Slug Snake are considered to be of some conservation value (Table 13‑27).
Table 13‑27 Reptile Species of Some Conservation
Value, Their Habitat Preferences and Observed Relative abundance within the
Assessment Area at Fung Lok Wai
|
Species
|
Conservation concern and distribution*
|
Recorded abundance
|
Habitat preference*
|
|
Banded
Krait
Bungarus fasciatus
|
Regional
concern
D
|
Rare
|
Low
lying areas near marshes, cultivated fields and shrub land
|
|
Common
Rat Snake Ptyas mucosus
|
Potential
regional concern
China
Red Data Book species
N/A
|
Rare
|
Varied
including agricultural areas, shrub land and around ponds and reservoirs
|
|
Indo-Chinese
Rat Snake
Ptyas korros
|
Potential
regional concern
China
Red Data Book species
N/A
|
Rare
|
Open
habitats, including banks of streams and reservoirs, cultivated fields, ponds
and shrub land
|
|
Many-banded
Krait Bungarus multicinctus
|
Potential
regional concern
N/A
|
Rare
|
Varied,
including forest, agricultural areas and the edges of mangroves
|
|
Mangrove
Water Snake Enhydris bennettii
|
Local
concern
C
China
Red Data Book species
|
Rare
|
Muddy
coastal habitats
|
Local
Distribution: A = known in this locality alone; B =
known to occur in two localities; C = known to occur in three to four
localities; D = known to occur in five to eight localities; E = known to occur
in nine to 16 localities; F = known to occur in 17 to 32 localities; N/A – no
local rating. * Levels of conservation concern and habitat preferences based on
Fellowes et al. (2002) and Karsen et al. (1998).
13.6.55
Although reptile species were
recorded throughout the Assessment Area, they were not abundant. Most were
recorded only on one occasion throughout the survey period.
13.6.56
Banded Krait is typically found
in low-lying areas particularly near marshes, areas under cultivation and in
shrub land. During the baseline surveys it was only recorded within the
Transects 1 and 2 which are centred on agricultural habitats in the southern
part of the assessment area. Common Rat Snake is found in a variety of
habitats, including agricultural land and shrubs, particularly close to water.
During the baseline surveys the only record of this species was from Transect 5
which is located to the west of the Tai
River. Indo-Chinese Rat
Snake is also typically found in Hong Kong in
a variety of habitats, including banks of streams and reservoirs, cultivated
fields, ponds and shrub land. During the baseline surveys it was only recorded
from Transect 10 which is located in hill-side woodland and scrub mosaic
habitats. Many-banded Krait is found in Hong Kong
in varied habitats including forest, agricultural areas and the edges of
mangroves. During the baseline surveys it was recorded in Transect 1 which is
focused on agricultural land uses in the southern part of the assessment site
and Transect 6 which runs adjacent to mangroves and fish ponds. Mangrove Water
Snake is associated with muddy coastal habitats although in the baseline
surveys it was only recorded from Transect 7 which is in the central fishpond
area.
Birds
Transect Surveys
13.6.58
A total of 142 species of bird
were recorded during surveys of the Assessment Area. Of these 116 species were
recorded within fishpond and associated wetland habitats and 68 species from
the hillside transects in the south of the site (see Appendices 13-10 and
13-11). Aquaculture ponds 63, 77 to 87 were not surveyed on 17 September 2001
due to severe flooding at the site preventing access to these ponds.
13.6.59
All bird species are currently
protected under the Wild Animals Protection Ordinance (Cap. 170). However,
there are considerable differences between species in relation to their distribution,
rarity, threat and overall conservation status.
13.6.60
Twenty-four bird species,
considered to be Species of Conservation Importance based on a range of
criteria, were regularly recorded in significant numbers at the site (see Table 13‑28). Most are strongly associated with wetland habitats,
including aquaculture ponds, permanent water courses, marsh, reed bed, wet
agriculture intertidal habitats. Due to the limited distribution of these
habitats in Hong Kong many of these species are largely restricted to the Deep Bay
area. In addition, bird of prey species (which were recorded rarely
foraging/flying over the site) were also included due to their large home
ranges and their sensitivity to disturbance.
Table 13‑28 Bird Species of
Conservation Importance Recorded in Significant Numbers within the Assessment
Area of Fung Lok Wai
|
Common name
|
Scientific
name
|
Protection
status
|
IUCN Redlist
Status
|
Hong Kong Fauna of conservation concern
|
Habitat preference in Hong Kong
|
|
Global
conservation concern
|
|
|
|
|
|
Black-faced
Spoonbill
|
Platalea minor
|
C, HK
|
EN
|
PGC
|
Mudflat, drained Gei wais and aquaculture
ponds
|
|
Greater Spotted
Eagle
|
Aquila
clanga
|
B1, B2, C, HK
|
VU
|
GC
|
|
|
Imperial Eagle
|
Aquila
heliaca
|
B1, B2, C, HK
|
VU
|
GC
|
Marshes, aquaculture ponds and adjacent
hillsides in Deep
Bay area. Also recorded in the NW, NE & central New Territories
|
|
Red-billed
Starling
|
Sturnus sericeus
|
HK
|
LC
|
GC
|
Aquaculture ponds, wet agricultural
areas, perimeter of reedbeds; and natural and artificial drainage channels.
|
|
Regional
conservation concern
|
|
|
|
|
|
Black Kite
|
Milvus migrans
|
HK
|
LC
|
RC
|
Sea, coast, intertidal mudflat,
aquaculture ponds, grassy and shrubby hillsides and harbours.
|
|
Common Teal
|
Anas crecca
|
B2, HK
|
LC
|
RC
|
Shallow wetlands including aquaculture
ponds
|
|
Eurasian Wigeon
|
Anas penelope
|
B2, HK
|
LC
|
RC
|
Intertidal areas, marsh and fishponds
|
|
Osprey
|
Pandion haliaetus
|
B2, C, HK
|
LC
|
RC
|
Bays, coastal areas, gei wais,
aquaculture ponds, reservoirs
|
|
Potential regional
conservation concern
|
|
|
|
|
|
Chinese Pond Heron
|
Ardeola bacchus
|
HK
|
LC
|
PRC
|
Freshwater marsh, aquaculture ponds and
bunds, wet agriculture, rivers and drainage channels.
|
|
Great Cormorant
|
Phalacrocorax carbo
|
HK
|
LC
|
PRC
|
Coastal areas, aquaculture ponds
|
|
Great Egret
|
Egretta alba
|
A, J, HK
|
LC
|
PRC
|
Wetlands, particularly shallow intertidal
bays, aquaculture ponds and marshes.
|
|
Grey Heron
|
Ardea cinerea
|
HK
|
LC
|
PRC
|
Abundant winter visito to Deep Bay
associated with freshwater marsh, aquaculture ponds and bunds, wet
agriculture, rivers and drainage channels.
|
|
Little Egret
|
Egretta garzetta
|
HK
|
LC
|
PRC
|
Wetlands including intertidal mudflats,
gei wai, also aquaculture ponds, wet agriculture, marsh and banks of rivers
and streams
|
|
Local conservation
concern
|
|
|
|
|
|
Black-crowned
Night Heron
|
Nycticorax nycticorax
|
HK
|
LC
|
LC
|
Coastal and sub-coastal wetlands,
including aquaculture ponds, marsh, mangrove, intertidal mudflats, riverine
wetlands
|
|
Cattle Egret
|
Bubulcus ibis
|
A, HK
|
LC
|
LC
|
Freshwater marsh, aquaculture pond bunds,
wet agriculture.
|
|
Collared Crow
|
Corvus torquatus
|
HK
|
|
|
Primarily in Deep Bay,
including rocky and sandy shores, intertidal mudflats, gei wai, aquaculture
ponds
|
|
Crested Serpent
Eagle
|
Spilornis cheela
|
C, HK
|
LC
|
LC
|
Hillside, woodland, rocky hilltops, undisturbed
small marshes, abandoned wet paddies
|
|
Little Grebe
|
Tachybaptus ruficollis
|
HK
|
LC
|
LC
|
Gei wai, aquaculture ponds particularly
those with emergent and submerged vegetation
|
|
Little Ringed
Plover
|
Charadrius dubius
|
A, HK
|
LC
|
LC
|
Low-lying land close to freshwater: wet
agriculture, reclaimed land, freshwater marsh, aquaculture ponds
(particularly when drawn down) & coastal areas adjacent to freshwater
streams
|
|
Pied Kingfisher
|
Ceryle rudis
|
HK
|
LC
|
LC
|
Fresh, brackish and saltwater wetlands
including aquaculture ponds, gei wai, sheltered bays.
|
|
Striated Heron
|
Butorides striatus
|
HK
|
LC
|
LC
|
Mangroves and inter-tidal mudflats
|
|
Temminck's Stint
|
Calidris temminckii
|
B2, HK
|
LC
|
LC
|
Feeds and roosts in drawn down
aquaculture ponds. Also forages in freshwater marsh.
|
|
White-throated
Kingfisher
|
Halcyon smyrnensis
|
HK
|
LC
|
LC
|
Golf courses, gardens, aquaculture
ponds.
|
|
Wood Sandpiper
|
Tringa glareola
|
A, B2, HK
|
LC
|
LC
|
Low lying areas of freshwater marsh, wet
agricultural land and aquaculture ponds in the New Territories
particularly Long Valley. During spring passage observed on the intertidal
mudflats.
|
Protection Status: B1 = listed on Appendix I of the Bonn Convention; B2
= listed on Appendix II of the Bonn Convention; A = listed under an agreement
between the Government of Australia and the Government of the People’s Republic
of China for the Protection of Migratory Birds and their Environment; J =
listed under an agreement on the Protection of Migratory Birds and their
Habitats between the Government of Japan and the Government of the People’s
Republic of China; C = protected in the People’s Republic of China; HK =
protected in the Hong Kong SAR;
IUCN Red List: Source: www.iucnredlist.org EN = Endangered; VU = Vulnerable;
LC = Least Concern
Hong Kong Fauna of conservation concern: Source: Fellowes et al. (2002) GC = Global Concern; RC = Regional Concern; PGC =
Potential Global Concern; PRC = Potential Regional Concern; LC = Local Concern.
13.6.61
Four species were recorded that
are considered to be of global conservation importance and these are described
in more detail in the paragraphs below.
13.6.62
Black-faced Spoonbill - Breeds on the
west coast of the Korean peninsula and in Liaoning,
northeast China.
Over winters in northern Vietnam,
southern and eastern China
including Deep Bay, Taiwan
and Japan.
It is a winter visitor to Hong Kong and
possibly a passage migrant. Highest
counts occur during autumn commencing in the third week of October. The species typically departs Hong Kong
during the second week of April, although small numbers have been recorded in Deep Bay
during the summer since 1984. BirdLife International estimates the world
population of this species to be 1,480 individuals. The over-wintering
population has increased since 1987-88 when peak winter counts were low (about
35 individuals) to a peak of 346 individuals in January 2006 (Anon 2006). Deep Bay
is a critically important to the survival of this species and, during winter,
has regularly supported about 20-25% of the world population. During these surveys Black-faced Spoonbill
was recorded within actively managed aquaculture ponds, particularly when ponds
were drawn-down.
13.6.63
Greater Spotted Eagle – This species is
a scarce and local winter visitor to the northern New Territories
primarily between the end of October and end of March. The winter population
appears to have declined probably due to at least in part to the disappearance
of domestic duck-farming in Deep
Bay area. This species
was observed very rarely during baseline surveys only once (during February)
overflying the assessment area from the hillside survey transect (Transect 6).
The scarcity of this species is reflected in the counts for both the Deep Bay
area (where a maximum of 4 individuals were recorded in winter 2004/05) and the
DBF recording area where there were no records reported during monitoring
surveys undertaken by the HKBWS (see Appendix 13-12). Greater Spotted Eagle
will forage for prey over aquaculture ponds and brackish and freshwater marshes
so the wetland habitats at Fung Lok Wai could comprise potential habitat,
although the rarity of observations in this area imply that the Hong Kong
population of this species has very little reliance upon it.
13.6.64
Imperial Eagle – This species is a common
winter visitor, possibly a passage migrant through Hong
Kong in February. Mainly observed during November to March, with
numbers peaking in mid-winter. The distribution of this species is closely
associated with the distribution of ducks, although is not often seen over
intertidal areas. During these surveys Imperial Eagle was observed rarely
over-flying the assessment area foraging for prey. This species was observed
rarely (although more frequently than Greater Spotted Eagle) during baseline
surveys with a maximum count of 2 individuals overflying the assessment area
seen in January. The scarcity of this
species is reflected in the counts for both the Deep Bay area (where a maximum
of 5 individuals were recorded in winter 2003/04 and 2004/05) and the DBF
recording area where a maximum of 1 individual was recorded in winter 2004/05
(see Appendix 13-12). Imperial Eagle will forage for prey over aquaculture
ponds, marshes and adjacent hillsides in Deep Bay area so the wetland habitats
at Fung Lok Wai could comprise potential habitat, although the rarity of
observations in this area imply that the Hong Kong population of this species
has very little reliance upon it.
13.6.65
Red-billed Starling - Breeds only in
China, however, it is a winter visitor in northern Indochina and an abundant
but localised winter visitor to Hong Kong, where it forms large flocks that are
considered to be of international significance. Recorded from the third week in
October, numbers peak during the first two weeks of November. Typically departs
Hong Kong during the second half of March. It
tends to occur in large flocks and is primarily recorded in Deep Bay, as
well as Long Valley, Kam Tin, Starling Inlet and
Shuen Wan. The protection of roost sites in inter-tidal forest habitats and the
intensification of aquaculture in the Deep Bay
area (which may have created increased feeding opportunities) possibly accounts
for the significant increase in the over-wintering population since the 1980s.
During these surveys Red-billed Starling was frequently recorded around
aquaculture ponds and adjacent to permanent watercourses during winter.
13.6.66
Of the 24 bird species of
conservation importance recorded within the Assessment Area, 20 species were
recorded within the Study Site (see Table
13‑29). Four additional species were recorded from the 500m buffer zone surveyed. No bird species of
conservation importance were recorded solely from the Proposed Development
Area. However, 11 species were recorded using the habitats within the Proposed
Development Area but all of these species were recorded in significant numbers
elsewhere on the site. The figures suggest that the aquaculture ponds of the
Proposed Development Area are similar to those found elsewhere within the Study
Site, they are of similar character and support a similar range of species.
Table 13‑29 List of Bird Species of
Conservation Importance Recorded in Each Section of the Assessment Area at Fung
Lok Wai.
|
Common name
|
Scientific
name
|
Proposed
Development Area
|
Study Site
|
Buffer Zone
|
|
Global
conservation concern
|
|
|
|
|
Black-faced
Spoonbill
|
Platalea minor
|
|
*
|
*
|
|
Greater Spotted
Eagle
|
Aquila clanga
|
|
|
*
|
|
Imperial Eagle
|
Aquila heliaca
|
|
*
|
*
|
|
Red-billed
Starling
|
Sturnus
sericeus
|
*
|
*
|
*
|
|
Regional
conservation concern
|
|
|
|
|
Common Teal
|
Anas crecca
|
|
*
|
*
|
|
Eurasian Wigeon
|
Anas penelope
|
|
*
|
*
|
|
Osprey
|
Pandion
haliaetus
|
|
|
*
|
|
Potential
regional conservation concern
|
|
|
|
|
Black Kite
|
Milvus migrans
|
*
|
*
|
*
|
|
Chinese Pond Heron
|
Ardeola bacchus
|
*
|
*
|
*
|
|
Great Cormorant
|
Phalacrocorax
carbo
|
*
|
*
|
*
|
|
Great Egret
|
Egretta alba
|
*
|
*
|
*
|
|
Grey Heron
|
Arda cinerea
|
|
*
|
*
|
|
Little Egret
|
Egretta
garzetta
|
*
|
*
|
*
|
|
Local
conservation concern
|
|
|
|
|
Black-crowned
Night Heron
|
Nycticorax
nycticorax
|
|
*
|
*
|
|
Cattle Egret
|
Bubulcus ibis
|
*
|
*
|
*
|
|
Collared Crow
|
Corvus
torquatus
|
|
*
|
*
|
|
Crested Serpent
Eagle
|
Spilornis
cheela
|
|
|
*
|
|
Little Grebe
|
Tachybaptus
ruficollis
|
*
|
*
|
*
|
|
Little Ringed
Plover
|
Charadrius
dubius
|
|
*
|
*
|
|
Pied Kingfisher
|
Ceryle rudis
|
*
|
*
|
*
|
|
Striated Heron
|
Butorides striatus
|
|
*
|
*
|
|
Temminck's Stint
|
Calidris
temminckii
|
|
|
*
|
|
White-throated
Kingfisher
|
Halcyon
smyrnensis
|
*
|
*
|
*
|
|
Wood Sandpiper
|
Tringa glareola
|
*
|
*
|
*
|
* Indicates presence
Flightline surveys
13.6.67
To understand patterns of bird
movement within the site the flight line data collected during bird flight line
surveys were collated and aggregated.
13.6.68
During the survey period 4052
individual birds were observed flying over some sector of the Study Site (Figure 13‑10). These flightline data recorded are summarised by
bird group and altitude category in Table
13‑30.
Table 13‑30 Abundance and Proportion
of Birds Observed Within the Study Site by Altitude Category (February-December
2001)
|
|
Height
|
|
|
Group
|
<20m
|
20-40m
|
40-60m
|
>60m
|
All
|
|
|
No.
|
%
|
No
|
%
|
No.
|
%
|
No.
|
%
|
No.
|
%
|
|
Ardeid
|
1,391
|
94.5
|
1,010
|
76.6
|
134
|
12.8
|
40
|
18.8
|
2,575
|
64
|
|
Waterbird
|
46
|
3.1
|
263
|
19.9
|
843
|
80.4
|
52
|
24.4
|
1,204
|
30
|
|
Raptor
|
35
|
2.4
|
46
|
3.5
|
71
|
6.8
|
121
|
56.8
|
273
|
6
|
|
Total
|
1,472
|
|
1,319
|
|
1,048
|
|
213
|
|
4,052
|
100
|
13.6.69
Ardeids (2575, 64%) are clearly
the most abundant group overall (Table
13‑30) and comprise, with other waterbirds (1204, 30%), 94%
of all individuals recorded. As would be expected raptors, overall account for
a small proportion of individuals observed (273, 6%). At lower altitudes
ardeids are clearly dominant, with Little Egret the most abundant species
recorded below 40m (Table 13‑31). Above 60m
Black Kite accounts for the majority of records. Great Cormorant are abundant
upwards of 20m and
dominant in the 40-60m altitude
category.
Table 13‑31 Dominant
Species by Altitude Category
|
Altitude
category
|
Dominant
species (number recorded)
|
|
<20m
|
Little Egret (848), Great Egret (291), Chinese Pond Heron (137)
|
|
20-40m
|
Little Egret (743), Great Cormorant (245)
|
|
40-60m
|
Great Cormorant (740)
|
|
60m+
|
Black Kite (113), Great Cormorant (52)
|
13.6.70
These data reflect the observed
behaviour of birds, with herons and egrets moving between ponds, often in short
hops at relatively low altitudes, as they forage. Raptors, such as Black Kites,
however, tend to forage at higher altitude, circling over ponds in search of
food.
13.6.71
A total of 529 birds, 13% of
all records for the site (4052), were observed flying through the sector of the
Assessment Area occupied by the Proposed Development Area. Whilst, initially,
this proportion seems high (the Proposed Development Area is only 5% of the
area of the Study Site) it must be recognised that the records for this sector
are not exclusive. That is, as birds fly through the site they intersect with
many different sectors. On the basis of the distribution of flightlines
revealed by the surveys, it is expected that any equivalent 4 ha sector located any where within the site
would intersect with a similar proportion of flightlines.
13.6.72
Data for all individuals at
each altitude category (Table
13‑32) indicates, however, that a disproportionately large
number of birds are flying below 40m
within the entire site (68.8%) and that for the proposed development sector
this proportion is even higher (93.9%).
Table
13‑32 Comparison of Total Individuals
for Each Altitude Category within the Study Site and the Proposed Development Area
|
Altitude
category
|
Total
individuals for
Study
Site
|
Total
individuals for Proposed Development Area
|
|
<20m
|
1,472 (36.3%)
|
255 (48.3%)
|
|
20-40m
|
1,320 (32.5%)
|
241 (45.6%)
|
|
40-60m
|
1,048 (25.9%)
|
15 (2.8%)
|
|
>60m
|
2,13 (5.3%)
|
17 (3.2%)
|
|
Total
|
4,052
|
528
|
Species composition
13.6.73
Analysis of the species
composition of those flights occurring within the sector of the site occupied
by the proposed development (Table
13‑33 and Table
13‑34 reveals a broadly similar pattern to those for the
entire site with the following exceptions:
·
A higher proportion of ardeid
species 92.4% (488 individuals) were observed within the footprint of the
proposed development compared to the Study Site as a whole where ardeids
comprised 64% of all individuals observed.
·
A much lower proportion of
waterbird species 1.5% (8 individuals) were observed within the Proposed
Development Area compared to the Study Site as a whole where waterbirds
comprised 23% of all individuals observed.
Table
13‑33 Abundance and Proportion of Birds Observed within the Proposed
Development Area by Altitude Category (February-December 2001)
|
|
Height
|
Totals
|
|
Group
|
<20m
|
20-40m
|
40-60m
|
>60m
|
|
|
|
No.
|
%
|
No.
|
%
|
No.
|
%
|
No.
|
%
|
Total
|
%
|
|
Ardeid
|
250
|
98.0
|
228
|
94.6
|
9
|
60.0
|
1
|
5.9
|
488
|
92.4
|
|
Waterbird
|
3
|
1.2
|
2
|
0.8
|
2
|
13.3
|
1
|
5.9
|
8
|
1.5
|
|
Raptor
|
2
|
0.8
|
11
|
4.6
|
4
|
26.7
|
15
|
88.2
|
32
|
6.1
|
|
Total
|
255
|
|
241
|
|
15
|
|
17
|
|
528
|
100
|
13.6.74
The most abundant species
observed within the Proposed Development Area were Little Egret and Chinese
Pond Heron (Table 13‑34), although the abundance of these species is expected
to have declined following the abandonment of the egretry (see below). The vast
majority of flightline activity for both Little Egret and Chinese Pond Heron
observed within the area of the proposed development were below 40m and occurred during the breeding season, April to July.
Table
13‑34 Dominant Species Recorded at Each
Altitude Category within the Proposed Development Area
|
Altitude category
|
Dominant species
|
|
<20m
|
Little Egret (191), Chinese Pond Heron (51)
|
|
20-40m
|
Little Egret (182), Chinese Pond Heron (35)
|
|
40-60m
|
Cattle Egret (5), Black Kite (4), Little Egret (4)
|
|
>60m
|
Black Kite (14)
|
Egretry
13.6.75
The relatively high proportion
of Little Egret and Chinese Pond Heron individuals recorded within the Proposed
Development Area can be largely explained by the establishment of an egretry on
the south-west perimeter of the Assessment Area during March 2001, the Shing Uk
Tsuen egretry. The flightlines of birds to and from this egretry tend to track
across the south west corner of the study site, particularly at lower altitudes
(<40m) (Figure
13.11). More recently it appears that this egretry has now been abandoned (see Anon 2005). It is anticipated that the continued abandonment of this egretry
will have two consequences for the analyses presented above:
·
The overall levels of flight
activity for ardeids will be less than that shown above.
·
There will be substantially
fewer flightlines within the Proposed Development Area, there being less reason
for birds to move between Fung Lok Wai and the South-western part of the
Assessment Area.
13.6.76
Another egretry has recently
been found at Ha Mei San Tsuen. This egretry is outside the Assessment Area and
is located so far away that the development would unlikely to have material
impact on the flight lines of this egretry. As far as foraging areas are
concerned, it is unlikely that birds from this egretry utilise ponds in the
development footprint more than was the case in Shing Uk Tsuen egretry.
Mammals
13.6.77
The mammal fauna of Hong Kong is poorly known compared to other fauna groups
and there is limited information about the occurrence of mammal species in the
Fung Lok Wai area. Opportunistic sightings of tracks, marks and scats indicate,
however, that at least two species are likely to utilise the Assessment Area:
Seven-banded Civet (Vivericcula indica)
and Small Asian Mongoose (Herpestes
javanicus). Neither of these species is threatened or
restricted in area and are not considered species of conservation importance.
13.6.78
There are a number of mammal
Species of Conservation Importance that were not recorded during the twelve
months of survey but are known to occur within similar habitats in the Deep Bay
area. These include: Eurasian Otter (Lutra
lutra) and Crab-eating Mongoose (Herpestes
urva). The large numbers of flying insects associated with fishponds and
agricultural land are also likely to support bat populations, including,
potentially, Noctule Bat (Nyctalus
noctula), Leschenault's Fruit Bat (Rousettus
leshenaulti) Lesser Yellow-house Bat (Scotophilis
kuhlii), though no bat roosts were observed during the survey period.
Conclusions
13.6.79
The Fung Lok Wai Assessment
Area supports a number of Species of Conservation Importance. In particular, it
is of significance for bird species.
13.6.80
Two species of Global
Conservation Concern, Black-faced Spoonbill and Red-billed Starling, are
directly reliant on the wetland areas of the Assessment Area. Two eagle species
of Global Conservation Concern have been recorded over the Assessment Area and
are known to predate upon wetland bird species (such as ducks) that are
themselves dependent upon the site. There are 20 other bird
species of Regional or Local Conservation Concern. With the exception of
Crested Serpent Eagle these are all waterbirds or raptors with a close
association with the Aquaculture Ponds habitat.
13.6.81
Other than birds the only other
Species of Conservation Importance identified during the baseline surveys are 5 species
of reptile: Banded Krait, Common Rat Snake, Indo-Chinese Rat Snake, Many-banded
Krait and Mangrove Water Snake.
13.6.82
In addition there are other
species of amphibian, reptile, mammal, invertebrates and plant that are
considered to be of some conservation value.
For these species the wetland habitats of the southern part of the
Assessment Area, within the 500m
Buffer Zone, including wet agriculture and freshwater marsh are particularly
important.
13.6.83
Surveys were completed in
January 2002 when most aquaculture ponds were under active management. Since
completion of the surveys there has been no change in wetland area, there has
been no in-filling of fish ponds, for example. There has, however, been a
change in management of fish ponds. Site visits undertaken in recent years,
including by WWF staff, indicate that relatively few ponds (about one quarter)
are now in active production (Janet
Lee, Pers. Comm.). For abandoned ponds, grass has encroached
into the open water from the side of the ponds and Water Hyacinth (Eichhornia crassipes) is abundant in some these. In the absence of active management,
bunds have become covered by long grass which reduces their attractiveness as
roosting sites for waterbirds.
13.6.84
As the extent of wetland has
not changed it is considered that the importance of the site for most species,
including birds that are not dependent on the active fishpond management (eg
Red-billed Starling) and non-avian fauna (such as reptiles) will be unchanged.
For those birds that are dependent on the active management of fish ponds
(including egrets and Black-faced Spoonbill) it is expected that the importance
of the site will have declined.
13.6.85
Since the completion of the
surveys the egretry at Shing Uk Tsuen has now been abandoned (Anon 2005) and
this is expected to reduce the activity of herons and egrets within Fung Lok
Wai.
13.6.86
It is considered that the
results of these surveys remain applicable to the assessment. Any changes
taking in place in the intervening period are expected to involve a reduction
in ecological value due to a reduction in management activity. This is likely
to effect bird species most as these tend to benefit from aquaculture
activities that periodically provide access to food resources.
13.7
Identification of Potential Impacts
Summary of proposed development
13.7.1
The proposed development
involves the conversion of approximately 4ha of aquaculture pond, located on the southern boundary
of the Fung Lok Wai study site, to residential development. The proposal
involves the construction of residential apartments, landscaping, car-parking
and other ancillary structures.
13.7.2
The proposed vehicular access
of the site, viz. the Southern Development Access, will be via the existing Fuk Shun Street and
Yuen Long Industrial Estate to
Yuen Long.
13.7.3
The construction and operation
of the residential development will result in direct habitat loss and short and
long-term disturbance to species of conservation importance (see below) as a
consequence mitigation is proposed in the form of a Wetland Nature Reserve
(WNR). This WNR will be constructed on the remaining, approximately 76.1 ha of the study site unaffected directly
by the residential development. The WNR will comprise a large expanse of
enhanced fishponds and re-recreated marshland habitat.
13.7.4
To minimise the impact of the
residential construction on sensitive species it has been decided that the WNR
will be constructed in advance of the residential development. This sequence of
development has the advantage of minimising the negative effects (particularly
disturbance) of residential construction, however, it also means that the
effects of the mitigation works themselves, including temporary habitat loss and
disturbance, on Species of Conservation Importance must also be considered in
the impact assessment.
13.7.5
The construction of the WNR is
divided into Sectors as described in Section 13.9. At each stage the maximum
area of pond unavailable due to construction works is shown along with the
remaining area unaffected by construction works.
Potential impacts
13.7.6
Initial analysis of baseline
data indicated three constraints on the proposed development:
·
The location of the egretry in
the southern part of the assessment area could result in flight line
interference of birds attempting to access food resources within Fung Lok Wai.
The preferred option, therefore, is to construct the residential development at
a location approximately 150m
eastwards of the original proposed location. This location remains the
preferred option even though the egretry is now abandoned;
·
Accessing the site from the
west adjacent to the Hong Kong
Wetland Park,
as originally proposed, will require additional construction work and,
potentially, disturbance to the egretry. The preferred option, therefore, is to
provide access to the residential development from the south through existing
roads; and,
·
It is desirable to conserve
existing wetland habitat and maintain linkages between all the wetland habitats
within the Fung Lok Wai assessment area, including the mosaic of wetlands in
the southern part of the Assessment Area. The WNR design has, therefore, been
modified to accommodate the relocated development area. The preferred design
for the WNR maintains connectivity with adjacent wetlands including those in
the southern part of the assessment area.
13.7.7
Section 3 describes, in more
detail, the development of the preferred options. Options 1A and 1B are considered to be broadly
similar in ecological terms. They occupy the same area, hence habitat loss will
be the same in each option nor is there considered to be a significant
difference between the two options in terms of disturbance, pollution, soil
compaction or hydrological disruption. The only slight difference between the
options is potential with respect to fragmentation and this is considered in
more detail below.
13.7.8
The following potential impacts
arising from the construction and operation of these preferred development
options are considered in more detail below:
·
Habitat loss;
·
Habitat fragmentation;
·
Disturbance;
·
Pollution;
·
Soil compaction; and,
·
Hydrological disruption.
Habitat loss
13.7.9
There will be no permanent
habitat loss to ecologically valuable habitats in the WCA or WBA. The actual
operation phase footprint (i.e. land directly and permanently lost by the
project) will be approximately 4.0 hectares (primarily Aquaculture Ponds with a
very small area of drainage channel). This change in habitat use will occur
within the WCA as a result of the land used for the construction of residential
blocks, associated structures and access roads and storage areas for materials
and equipment etc. However the loss of water body is compensated by
re-profiling the ponds in the WNR area. This creates ecologically enhanced and
enlarged ponds, and recreated marshland habitat. The construction and ongoing
management of these habitats (as outlined in the HCMP) is anticipated to fully
compensate any potential loss of wetland ecological function arising from the
effects of the residential development. In particular management will be
focused on maintaining the population levels of key Species of Conservation
Importance, including waterbirds. Consequently under the proposal there is no
net loss of water body area or ecological function. No additional habitat loss
is anticipated as a result of the construction of either sewerage strategy or
the preferred (southern) access route.
13.7.11 An integral component of the proposal is the development of a
Wetland Nature Reserve (WNR) on the remaining 76.1 hectares of the site. The
creation of the WNR will involve the transformation of approximately 14.4
hectares of aquaculture ponds to freshwater marsh and the enhancement (through
enlargement) of 61.7 hectares of aquaculture ponds. Whilst intended to
compensate for impacts arising from the construction of the residential
component of the development and, therefore, expected to have overall positive
benefit, the WNR works will involve permanent and temporary habitat loss of
aquaculture ponds (fishponds that are actively managed, those that are
currently unmanaged, and the intervening bunds) and ditches and drainage
channels.
Habitat Fragmentation
13.7.12
Construction of the proposed
development along the southern edge of the study site is not likely to result
in significant fragmentation of habitat areas either within the study site or
from other wetland areas in the WCA, the WBA and Ramsar site or other
identified sensitive ecological receivers. Construction may create a temporary
barrier to dispersal particularly for small vertebrate species such as
amphibians and small mammals utilising the mosaic of habitats in the southwest.
This area consists of a mosaic of small ponds, drainage channels, wet
agriculture and reedbed. No additional habitat fragmentation is anticipated as
a result of the construction of either sewerage strategy or the preferred
(southern) access route.
13.7.13
The egretry at Shing Uk Tsuen was
located to the south west of the Proposed Development Area within an area of
Fung-shui woodland. Construction of the development at this originally proposed
location would have directly obstructed flightlines and reduced sightlines
between the egretry and fishpond foraging areas. The preferred development
options (1A and 1B)
have been relocated to reduce this effect. The dramatic reduction in flightline
obstruction achieved through this relocation is illustrated in Table 13‑35. Several conservative assumptions made in this
analysis probably, however, result in an over-estimate of flightline
obstruction including:
·
All flightlines intersecting
with the footprint of the proposed Development Area will be completely
obstructed. In practice it is anticipated that open space within the
development will provide opportunities for passage, although this effect is
expected to be small; and,
·
Birds will not modify their
flightlines to pass around the development to forage in the ponds beyond. In
practice it is expected that birds may take a more circuitous route to access
food resources. The magnitude of this effect is not known.
Table
13‑35 Comparison of Potential
Affect on Egretry Flightlines of Alternative Development Scenarios
|
|
Original location
|
Preferred option
(Relocated 150m eastwards)
|
|
Number
(percentage) of flightlines from egretry intersecting with Proposed
Development Area
|
330 (65%)
|
120 (24%)
|
13.7.14
The abandonment of the egretry
(see Anon 2005) is expected to significantly reduce the number of flightlines
passing through the proposed development area, there being less reason for
birds to move between Fung Lok Wai and the South-western part of the Assessment
Area. There is no indication that the flightlines of other species are likely
to be significantly affected by the construction or operation of the
residential development as the numbers of other (non-ardeid) species observed
during flightline surveys was relatively very low (see Tables 13-33 and 13-34),
this includes Great Spotted Eagle, Imperial Eagle, Crested Serpent Eagle and
Osprey.
13.7.15
Options 1A and 1B are similar in many respects, the
only slight difference between these two options arising from the larger number
of buildings in Option 1B. The buildings in Option 1A will be slightly higher
(14-18 stories) than those proposed in Option 1B (all 15 stories). It is
considered that the effects of reducing the spacing of buildings will reduce
sightlines to a greater extent than the slight differences in building height
proposed. On this basis it is concluded that Option 1B will have a slightly
greater impact, with respect to this effect, than Option 1A.. It is emphasised
that the difference between these options is slight, particularly in light of
the abandonment of the egretry, as it was the potential blockage of flights to
and from this feature that was the principal source of concern with respect to
habitat fragmentation, and neither are expected to cause significant barrier
effects to ardeids or any other species, including raptors.
Disturbance
13.7.16
General disturbance effects are
widely recognized and have been documented in the past (e.g. Hockin et al. 1992). Such effects may include
the complete avoidance of an area (which is therefore comparable to habitat
loss) and reduced densities (e.g. where only certain less-sensitive or
accustomed individuals use the area). Other less-obvious disturbance effects
may include reduced habitat quality through reduced feeding efficiency (e.g.
because of a need for increased vigilance), which may in turn lower survival
rates or breeding output. Care must therefore be taken in interpreting the
observation of a species close to a disturbance source as being evidence that
there is no disturbance effect. On the other hand, the observation that there
is a disturbance effect, may not necessarily mean that this results in a
population impact, as animals may, for example, move to alternative areas if
suitable habitat is in excess (i.e. populations are not at carrying capacity).
13.7.17
According to Hill et al. (1997) the severity and overall
impact of disturbance (at least on birds) is likely to depend on the following
factors:
·
Intensity of disturbance;
·
Duration and frequency of
disturbance (continuous, infrequent, regular, variable);
·
Proximity of source;
·
Seasonal variation in
sensitivity of affected species;
·
Presence of people associated
with the source;
·
Whether animals move away, but
return after disturbance ceases;
·
Whether important numbers are
affected;
·
Whether there are alternative
habitats available nearby;
·
Whether rare, scarce or
especially shy species are affected.
13.7.18
In particular, disturbance
impacts are normally greatest when they are close and frequent. Although, some
species can adapt to regular disturbances from noise and moving machinery, the
close proximity of people is rarely adapted to. Thus, species tend to show
increasing responses across a gradient of severity, from passive-low-level and
continuous to active-high-level continuous (Hockin et al. 1992).
13.7.19
Although the long-term aim of
the design of the WNR is to enhance the area for wildlife, the construction of
the development and the proposed enhancement works will cause both permanent
and temporary disturbance impacts to Species of Conservation Importance
utilising the assessment area. Potential disturbance impacts will include:
·
Permanent disturbance from
normal residential activities such as noise and visual disturbance from people,
vehicles and pets.
·
Permanent disturbance from
fishpond management activities, however this level of disturbance activity will
be lower than currently exists on site, due to a reduction in fishpond
operation recommended under the proposed management strategy, though this may
be offset by an increase in visitors to the reserve.
·
Permanent disruption of a
proportion of flightlines to and from the egretry (now abandoned) due to the
location of the residential units and access road.
·
Disruption of flightlines and
temporary noise and visual disturbance to birds during construction of
residential units.
·
Temporary direct disturbance to
individual ponds during the improvement of fishponds within the WCA.
·
Temporary noise and visual
disturbance to the fishpond area from site traffic during construction of the
development and Wetland Nature Reserve.
13.7.20
Noise level measurements
carried out as part of this assessment indicate that predicted unmitigated
noise levels during construction of the residential area may exceed noise
limits for daytime construction activities as set out in Annex 5 of the
EIAO-TM. Predicted noise levels can be brought within the noise limits through
appropriate mitigation. However, it is predicted that some noise levels may
reach 71-75dB at noise sensitive receivers on the south west boundary (see
Section 4). These levels, although within acceptable noise limits, are likely
to have some impact on sensitive species.
13.7.21
No additional disturbance is
anticipated as a result of the construction or operation of sewerage strategy
“A” which will follow existing roads. Sewerage strategy “B” will require some
additional construction works to the west of the proposed development area and
WNR, however, these works are not expected to create significant additional
disturbance because they are: limited in extent; confined to areas that are
already disturbed; and, of relatively short duration compared to construction
work on the main development.
13.7.22
Construction and operation of
the preferred (southern) access route is not expected to cause significant
additional disturbance as it will follow existing roads and is remote from the
fishpond areas that are considered to be most sensitive to disturbance effects.
Pollution
13.7.23
Fugitive dust emissions from
construction activities could result in significant ecological impacts
primarily through deposited on nearby vegetation. This can cause vegetation damage,
which can have secondary impacts on associated fauna (such as insects and
birds).
13.7.24
Dust and exposed earth from
construction operations may also enter watercourses through run-off,
particularly during heavy rainfall periods. This can lead to high turbidity
from soil particles and eutrophication as a result of nutrient enrichment (as
phosphates, which are normally the limiting nutrient in freshwater systems, are
bound to soil particles). Aquatic macrophytes may be reduced or lost completely
as a result of reduced light penetration due to the increased turbidity from
soil particles and increased free-floating algae populations following
eutrophication. Severe eutrophication can also lead to oxygen depletion and the
impoverishment of aquatic animal communities and, in turn, other animals, such
as waterbirds, that feed on them. However, as reported under the water quality
impact assessment chapter, the water quality in existing watercourses is poor
and their ecological quality is low. Ecological degradation of these habitats
may not, therefore, occur if pollutant levels in site run-off are not
significantly above those of the watercourses, or if the run-off volume is
relatively low. Additional sediment inputs, and potential associated additional
nutrients loads may, however, have off-site impacts on the Deep Bay
mudflats and coastal waters. Mitigation measures must be put in place to
prevent adverse impacts on the ecological resources of Deep Bay.
13.7.25
Mitigation measures are
designed to strive towards minimal pollution of watercourses from the
construction and ongoing operation of the residential development and Wetland
Nature Reserve are dealt with in more detail in the water quality chapter of
this report.
13.7.26
Spills and run-off from
construction sites can sometimes contain high levels of toxic pollutants (such
as oil) which can cause direct mortality of plants and animals (in severe
cases), sub-lethal impacts (e.g. by reduced breeding success) or indirect
effects through impacts on food resources etc. Contamination of watercourses
may have off-site effects on ditches, rivers and the valuable estuarine waters
and mudflats of Deep
Bay.
13.7.27
Bioaccumulation may also occur
where toxic substances are passed up the food chain in increasing
concentrations. As a result top level predators such as some reptiles, mammals
and birds of prey can be particularly susceptible. Again, measures which should
be put in place to prevent this impact are described in the water quality
chapter of this report.
13.7.28
Mitigation measures, including
the provision of twin pipelines will ensure that the impacts of emergency
discharge from sewer bursting are controllable and that the need to shut down
the pump house or to discharge untreated sewage into natural streams or
channels is minimised.
Soil Compaction
13.7.29
During construction, areas of
land will be cleared for use as works areas. In addition, during fishpond
enhancement work heavy machinery will be required to access areas of the site
by tracking along bund ridges of the aquaculture ponds. During this period,
some areas of ground, which are currently undisturbed, will be compacted for
use as storage areas, vehicle movement or other purposes. Wetland areas into
which rain quickly infiltrates, will become hardened and rainfall will wash
off, taking sediment with it, to be deposited on land adjacent to the compacted
site, or in watercourses. The wetland function of these areas may therefore be
lost temporarily. Although the impact is temporary, extensive compaction over a
long period will make habitat restoration more difficult because of the need to
re-establish the soil base for a wetland area.
Hydrological
Disruption
13.7.30
The change in function of 14.4
hectares of aquaculture ponds to freshwater marsh will result in the necessary
diversion of a small catchment runoff southwest of the study site to the
southeast. The altered route of the catchment runoff should have no negative
impact on the hydrology of the site.
13.7.31
Stormwater run-off from the
development area will be directed into the fresh water marsh storage through appropriate
silt and oil filters and is not expected to adversely affect water quality
within this habitat.
Summary
13.7.32
Various types of habitats
(those considered to be of moderate value and above) affected by the potential
impacts of the proposed development identified above are summarised in Table 13‑36The significance of these potential impacts are
assessed individually in Section 13.8.
13.7.33
The potential impacts under
Options 1A and 1B on habitats are
similar, although, as indicated above the effects of habitat fragmentation are
expected to be slightly greater under Option 1B than 1A.
Table 13‑36 Summary Matrix of Potential Impacts on Various Types of Habitats
|
Habitat
|
Habitat loss
|
Habitat fragmentation
|
Disturbance
|
Pollution
|
Soil compaction
|
Hydrological disruption
|
|
Intertidal
forested wetlands
|
|
|
X
|
X
|
|
|
|
Permanent
rivers, streams and creeks
|
|
|
|
|
|
|
|
Ditches and
drainage channels
|
X
|
|
|
|
|
X
|
|
Aquaculture
pond
|
X
|
|
X
|
X
|
X
|
|
|
Reedbed
|
|
X
|
X
|
X
|
|
|
|
Permanent freshwater
marsh and pools
|
|
X
|
X
|
X
|
|
|
|
Seasonally
flooded (wet) agricultural land
|
|
X
|
X
|
X
|
|
|
|
Dry
agricultural land
|
|
|
X
|
X
|
|
|
|
Inactive
agricultural land
|
|
|
X
|
X
|
|
|
|
Orchard
|
|
|
|
|
|
|
|
Fung-shui woodland
|
|
(X)*
|
X
|
X
|
|
|
|
Semi-natural secondary woodland
|
|
|
X
|
X
|
|
|
|
Plantation woodland
|
|
|
|
|
|
|
|
Grassland
|
|
|
|
|
|
|
|
Grassland –
shrubland mosaic
|
|
|
|
|
|
|
|
Landscaped area
|
|
|
|
|
|
|
|
Works in
progress
|
|
|
|
|
|
|
|
Wasteland
|
|
|
|
|
|
|
|
Developed area
|
|
|
|
|
|
|
Note: * only if
egretry present
13.8.1
Options 1A and 1B are considered to be broadly
similar in ecological terms. They occupy the same area, hence habitat loss will
be the same in each option nor is there considered to be a significant
difference between the two options in terms of their potential impacts on sites
of conseration importance or the effects of disturbance, pollution, soil
compaction or hydrological disruption on habitats. The only slight difference
between the options is potential with respect to habitat fragmentation,
particularly with respect to the obstruction of the flightlines of birds, and
this is considered in more detail below.
Impacts on Site of Conservation
Importance
13.8.2
In Section 13.4 the following
sites of conservation importance were identified within the north-west New Territories:
·
Inner Deep Bay SSSI
·
Mai Po Inner Deep Bay Ramsar Site
·
Tsim Bei Tsui SSSI and egretry
·
Mai Po Nature Reserve and Mai Po Marshes SSSI
13.8.3
In addition the Study Site is
located within the Deep Bay WCA. The Assessment Area is also adjacent to the Hong Kong Wetland Park.
13.8.4
Fung Lok Wai is sufficiently
distant from the four key sites of conservation importance in the region that
the risk of adverse effects arising from either the construction or operation
of the Residential Development is considered to be very low. Disturbance
effects caused during construction and operation are not, for example, expected
to cause impact even to the most sensitive species beyond 500m from the Proposed Development Area. In
Section 12 it was also concluded that there was a very low likelihood of
impacts to marine habitats and hence marine components of the Mai Po Inner Deep Bay
Ramsar Site and the Inner Deep Bay SSSI.
13.8.5
There will be no permanent
habitat loss to ecologically valuable habitats in the WCA or WBA. The actual
operation phase footprint (i.e. land directly and permanently lost by the
project) will be approximately 4.0 hectares (primarily Aquaculture Ponds with a
very small area of drainage channel). This change in habitat use will occur
within the WCA as a result of the land used for the construction of residential
blocks, associated structures and access roads and storage areas for materials
and equipment etc. However the loss of water body is compensated by
re-profiling the ponds in the WNR area. This creates ecologically enhanced and
enlarged ponds, and recreated marshland habitat. The construction and ongoing
management of these habitats (as outlined in the HCMP) is anticipated to fully
compensate any potential loss of wetland ecological function arising from the
effects of the residential development. In particular management will be
focused on maintaining the population levels of key Species of Conservation
Importance, including waterbirds. Consequently under the proposal there is no
net loss of water body area or ecological function. No additional habitat loss
is anticipated as a result of the construction of either sewerage strategy or
the preferred (southern) access route.
13.8.6
The construction of the WNR
adjacent to the Hong Kong Wetland Park
is considered to be a positive feature as these two sites will collectively
increase the availability of wetland habitat managed explicitly for
conservation purposes in this part of the north-west New Territories.
13.8.7
Overall the proposed
development is expected not to have an impact on sites of conservation
importance.
Habitat Impacts
13.8.8
The project will transform
approximately 80.1 hectares of fishponds into a Residential Development and a
Wetland Nature Reserve with, overall, a greater variety of wetland habitats and
associated flora and fauna than that which currently exists. The WNR will be
actively managed in the short and long term, for the benefit of Species of
Conservation Importance identified utilising the site as well as other species
associated with the Deep
Bay environment.
13.8.9
The improvement of these
habitats will inevitably result is some short-term disturbance while habitats
are modified, restored and created. The impacts on habitats identified in the
previous section that will be partially lost/changed or fragmented during this
process, and those habitats that support Species of Conservation Importance
that may be lost, changed or fragmented, are assessed in Table 13‑37 to Table 54. In addition, all other habitats of
moderate or high value have been assessed according to the criteria outlined in
Annex 8 of the EIAO – TM.
Habitat Loss
13.8.10
Construction and operation of
the proposed development will result in temporary loss of habitats in the WCA
due to the operational phase footprint. This will impact aquaculture ponds (a
habitat that incorporates fishponds that are actively managed, those that are
currently unmanaged, and the intervening bunds) and a small area of Ditches and
Drainage Channels. However there is no net loss of water body due to pond
re-profiling and enhancement works. The impacts to these habitats are assessed
below.
Table 13‑37 Summary of Impacts to Aquaculture Ponds from Habitat Loss
|
Criteria
|
Remarks
|
|
Habitat Quality
|
High
|
|
Species
|
Numerous Species
of Conservation Importance (particularly waterbirds) are associated with
fishponds
|
|
Size/abundance
|
Approximately 4.0
hectares lost to the development. Within the proposed WNR approximately 14.4
hectares will be permanently converted to freshwater marsh and approximately
61.7 hectares subject to pond enhancement resulting in temporary loss during
the construction phase
|
|
Duration
|
Aquaculture ponds
within development area will be permanently lost. Those ponds converted to
freshwater marsh will be permanently lost (considered to be of higher
ecological value) and those subject to enhancement works will be temporarily
lost during the construction phase, however there is no net loss of water
body due re-profiling of ponds creating enlarged ponds (of higher ecological
value)
|
|
Reversibility
|
Impact is irreversible
for those ponds lost to development and converted to freshwater marsh. Impact
is reversible for those ponds subject to enhancement works
|
|
Magnitude
|
High
|
Table 13‑38 Summary
of Impacts to Ditches and Drainage Channel from Habitat Loss
|
Criteria
|
Remarks
|
|
Habitat Quality
|
Low
|
|
Species
|
The drainage
channels on site are of low water quality and support no Species of
Conservation Importance
|
|
Size/abundance
|
There are
approximately 0.4 hectares of ditches and drainage channels within the WNR,
of these approximately 0.02 hectares will be lost. Other sections will be
modified to facilitate drainage within the WNR
|
|
Duration
|
Permanent loss of
approximately 0.02 hectares, temporary disturbance to remaining sections during
WNR construction phase
|
|
Reversibility
|
Impact is
irreversible
|
|
Magnitude
|
Low.
|
Habitat Fragmentation
13.8.11
Some habitats located in the
south-western part of the assessment area form a mosaic of wetlands that are of
value to some fauna groups including invertebrates, amphibians and reptiles.
With regard to habitat fragmentation, this mosaic of habitats is assessed as a
single block (Table
13‑39). In addition the construction of the residential
development will cause some fragmentation of the linkage between the egretry at
Shing Uk Tsuen and the Fung Lok Wai fishponds through flightline interference,
although it is now apparent that this egretry has been abandoned. This impact is assessed in Table 13‑40 in light of the decision to relocate the development
eastwards specifically to avoid flightlines.
13.8.12
Prior to construction fencing
will be erected around the perimeter of the site. Within construction areas,
works area hoarding will also be erected. Perimeter fencing will comprise a
chain link fence to prevent unauthorised access to the site. The fence will not
be a completely impervious barrier to wildlife, there will be gaps associated
with access routes and small animals, such as reptiles and amphibians are
expected to pass through the fence unhindered. Birds will be able to pass over
the fence and, as it is chain link, it will not obstruct site lines. There is
potential, however, for the fence to obstruct the movement of medium and large
mammals, such as Eurasian Otter (Lutra
lutra) and Crab-eating Mongoose (Herpestes
urva). These impacts are considered separately below under Impact on
Species of Conservation Importance.
Table 13‑39 Summary of Impacts to
Wetland Mosaic Habitats (Including Wet Agriculture, Reedbed, and Freshwater
Marsh) from Habitat Fragmentation
|
Criteria
|
Remarks
|
|
Habitat Quality
|
Mixed:Reedbed –
low
Seasonally flooded
agricultural land – moderate
Permanent freshwater marsh and
pools – low to moderate
|
|
Species
|
The mosaic of
wetland habitats is of value to fauna groups such as invertebrates,
amphibians and reptiles. For the majority of this mosaic the existing direct
linkage to Fung Lok Wai fishponds will be retained.
|
|
Size/abundance
|
The area of this
wetland mosaic is approximately 4.9 hectares. This area will remain intact
and most of it will retain direct linkage to the proposed WNR. The
eastern-most part of the mosaic will loose direct connection to the Fung Lok
Wai fishponds following construction of the residential development. This
area will, however, still retain linkage to other parts of the mosaic.
|
|
Duration
|
Permanent
|
|
Reversibility
|
Impact is
irreversible
|
|
Magnitude
|
Low due to
maintenance of links with proposed freshwater marsh.
|
Table 13‑40 Summary of Impacts to Fung-shui Woodland from Habitat Fragmentation
|
Criteria
|
Remarks
|
|
Habitat Quality
|
Low to Moderate
(but high if egretry is present)
|
|
Species
|
Woodland comprises mixture of native and planted
tree and shrub species. The value of this woodland derives, however, from its
use as a nesting site (egretry) by species such as, for example, Little Egret
and Chinese Pond Heron. This egretry is now abandoned.
|
|
Size/abundance
|
1.3 hectares of
woodland. A survey undertaken in June 2001 indicated that the egretry
possessed up to 74 nests located within approximately 0.2 ha of the woodland. More
recent inspections indicate that the egretry has been abandoned
|
|
Duration
|
None
|
|
Reversibility
|
No impact
|
|
Magnitude
|
No
Impact
Impact
on herons and egrets using egretry is considered below under Impact on
Species of Conservation Importance.
|
13.8.13
In this section Options 1A and 1B are considered to be similar in
many respects, the only slight difference between these two options arising
from the larger number of buildings in Option 1B. The gaps between buildings
will be smaller in this option creating a slightly greater blockage of
sightlines for birds. It is predicted, therefore, that Option 1B will result in
slightly greater habitat fragmentation than Option 1A. It is emphasised that the difference between these
options is slight, particularly in light of the abandonment of the egretry, as
it was the potential blockage of flights to and from this feature that was the
principal source of concern with respect to habitat fragmentation. Flight line
surveys undertaken at the proposed development area did not indicate
significant levels of flight for any other bird species and so there is no
indication that either option would significantly impact the flightlines of any
bird species.
Disturbance
13.8.14
Disturbance can be caused
during construction and operation phases. Disturbance primarily affects animal
species and these impacts are considered in more detail below. For some
habitats, however, their importance is largely derived from the species they
support. At Fung Lok Wai this includes Aquaculture Ponds and Fung-shui Woodland. The impact of
disturbance on these habitats could be significant if it resulted in their supporting
reduced populations of Species of Conservation Importance. Disturbance effects
arising from glare (sunlight reflecting from glass surfaces during the daytime)
and night-time lighting are included in this section. It is expected that light
disturbance will only potentially affect bird species. Effects on other species
are not expected to be significant.
13.8.15
With respect to glare, as
discussed in Chapter 11, construction activities will not extend into the night
so night glare during this phase will be very limited. During the operational
phase, night-time lighting levels are also expected to be low. The residential
development landscape will not require 24 hour lighting except for the lighting
of access roads and emergency access.
Any potential effects of lighting at low levels will be reduced through
the use of the proposed landscape buffer along the periphery of the development
and roadside planting. The effect of glare at these lower levels can also
further reduced through the use of full cut off lighting.
13.8.16
The intensity, luminance and
lighting level generated from residential properties is also predicted to be
relatively low. The effects of glare (during the day and at night, at all
building levels) are considered to be part of the disturbance that will result
in the exclusion and disturbance distances identified for individual bird
species (see below). It is not predicted that the effects of lighting at night
at higher levels of buildings would cause disturbance beyond these disturbance
distances.
Table
13‑41 Summary
of Impacts to Aquaculture Ponds from Disturbance
|
Criteria
|
Remarks
|
|
Habitat Quality
|
High
|
|
Species
|
Disturbance during
construction and operation of the residential development will cause impact
to Species of Conservation Importance utilising this habitat, in particular
wetland bird species and large birds of prey.
|
|
Size/abundance
|
Assessments of the
sensitivity of bird species to disturbance including analysis of disturbance
effects (see below) indicates that, during construction, the effects of
disturbance on the most sensitive species may be detectable up to 500m from source with
exclusion expected within 200m.
For most species, however, these distances will be lower.
During operation,
levels of disturbance are expected to be lower and hence disturbance effects
for most species will be more limited in their extent.
In evaluating the
magnitude of disturbance effects, consideration has been given to noise,
human presence, daytime glare(from reflective surfaces which may increase the
visibility of the residential development during the daytime) and nightime
glare (it is assumed that lighting will increase the visibility of buildings
at night). The magnitude of glare effects is not expected to be large, the
development is located in the south-eastern part of the assessment area,
consequently the periods when sunlight will be reflected onto fishpond areas
will be limited. Nightime glare is not expected to affect large areas of
fishponds as the intensity of lighting used in residential developments is
relatively low.
|
|
Duration
|
The total
construction period for the proposed development is approximately 6 years.
During this period the level of disturbance is expected to be discontinuous
depending on the specific activities being undertaken (see Chapter 5 for
details of noise assessment). The most significant noise generating
activities include site formation and foundation works (including piling).
The greatest noise levels will, therefore, tend to be experienced in the
early stages of construction.
Light pollution,
to the exent that it will affect fauna, will persist for the lifetime of the
development.
|
|
Reversibility
|
Reversible
|
|
Magnitude
|
High
|
Table 13‑42 Summary
of Impacts to Fung Shui Woodland (Including Egretry) from Disturbance
|
Criteria
|
Remarks
|
|
Habitat Quality
|
Low to Moderate
(High if egretry present)
|
|
Species
|
The egretry within
the Fung-shui Woodland
is used by some bird species, including Little Egret and Chinese Pond Heron,
for nesting
|
|
Size/abundance
|
A survey
undertaken in June 2001 indicated that the egretry possessed up to 74 nests
located within approximately 0.2 ha
of the woodland. More recent inspections indicate that the egretry has been
abandoned.
|
|
Duration
|
The total
construction period for the proposed development is approximately 6 years.
During this period the level of disturbance is expected to be discontinuous
depending on the specific activities being undertaken (see Chapter 5 for details
of noise assessment). The most significant noise generating activities
include site formation and foundation works (including piling). The greatest
noise levels will, therefore, tend to be experienced in the early stages of
construction.
Any disturbance
during the breeding season (March to August) will be most significant
|
|
Reversibility
|
It is not known to
what extent any potential abandonment of the egretry (if present) could be
reversed
|
|
Magnitude
|
Low (The potential
impact of disturbance on the egretry (if present) could be high).
The relocated
development now lies, at its closest point, 200m from the previous location of the egretry. If
the egretry were to re-establish it is possible, considering the sensitivity
of the likely nesting species, that noise and vibration created during
construction could cause some disturbance. It is unlikely, however, that the
operation of the development will cause significant disturbance to any
nesting birds. The development has been relocated eastwards to minimise potential
flight barrier effects
|
Table
13‑43 Summary
of Impacts to Intertidal Forested Wetland from Disturbance
|
Criteria
|
Remarks
|
|
Habitat Quality
|
Moderate to high
|
|
Species
|
No Species of
Conservation Importance are likely to be affected
|
|
Size/abundance
|
The majority of
this habitat is considered too remote from the construction site to be
adversely affected by disturbance effects
|
|
Duration
|
A small area of
this habitat (<1 ha.)
is located within 400m
of the western part of the proposed construction site. During the early
phases of construction it is possible that some disturbance could be
experienced within this habitat although the impact is considered to be low
|
|
Reversibility
|
Reversible
|
|
Magnitude
|
Low
|
Table 13‑44 Summary
of Impacts to Wetland Mosaic Habitats (including Wet Agriculture, Reedbed, and
Freshwater Marsh) from Disturbance
|
Criteria
|
Remarks
|
|
Habitat Quality
|
Low to moderate
|
|
Species
|
The mosaic of
wetland habitats is of value to fauna groups such as invertebrates,
amphibians and reptiles. These species are not considered to be sensitive to
disturbance effects
|
|
Size/abundance
|
Approximately 4.9 ha.
|
|
Duration
|
Construction and
operation phase
|
|
Reversibility
|
Reversible
|
|
Magnitude
|
Low
|
Table 13‑45 Summary
of Impacts to Dry/Inactive Agricultural Land from Disturbance
|
Criteria
|
Remarks
|
|
Habitat Quality
|
Low to moderate
|
|
Species
|
No Species of
Conservation Importance are likely to be affected
|
|
Size/abundance
|
Small
|
|
Duration
|
Construction and
operation phase
|
|
Reversibility
|
Reversible
|
|
Magnitude
|
Low
|
Table 13‑46 Summary
of impacts to Semi-natural Secondary Woodland
from Disturbance
|
Criteria
|
Remarks
|
|
Habitat Quality
|
Low to moderate
|
|
Species
|
No Species of
Conservation Importance are likely to be affected
|
|
Size/abundance
|
Small
|
|
Duration
|
During
construction phase
|
|
Reversibility
|
Reversible
|
|
Magnitude
|
Low
|
Pollution
13.8.17
The impacts of potential
pollution events arising from the construction and operation of the development
on habitats are considered below. The magnitude of the impact pollution events
will depend on the nature of the pollutant, its source and the duration of the
event.
13.8.18
During construction the main
potential source of pollution is from fugitive dust, accidental release of
fuel, accidental release of other chemicals associated with construction
activities and sediment dispersal from exposed ground.
13.8.19
During operation, the main potential
source of pollution impact will arise if a sewage pipe bursts or an emergency
by-pass of the sewage pump house is required. The preferred option for the
disposal of sewage is Strategy A2 described in Chapter 8. New sewage pipes laid under
this strategy (and Strategy A1) follow existing roads and avoid sensitive
habitats. In any event the use of twinned sewage pipes will enable the impacts
of sewer bursts to be controlled. The risk of significant impact arising from
pollution due to pipe failure is, therefore, considered to be extremely small.
13.8.20
Strategy B follows a western route
and would involve the laying of pipes beneath the freshwater marsh and adjacent
to several Aquaculture ponds to the west of the WNR. As in Strategy A, the use
of twinned pipes will enable control of sewage in the event of a burst pipe.
Whilst the risk is low, the magnitude of any impact arising because of a sewage
leak along this route would be greater than for Strategy A2 (or A1) due to the
proximity of sensitive habitats. On ecological grounds, therefore, Strategy A2
is preferred.
13.8.21
All strategies, however,
involve the construction of an on-site sewage pump house. In the event of an
emergency or power failure, sewage may need to be diverted past this station.
To avoid potential impact a by-pass pipe will be installed to direct sewage to
the Tai River via Channel “X” thus avoiding the
potential for contamination of sensitive freshwater marsh and Fish Pond
habitats of the WNR.
13.8.22
There is also potential for
light pollution during operation. Sunlight reflecting from glass surfaces
during the daytime and from lighting at night could disturb birds. This affect
has already been considered under potential disturbance impacts above.
Table
13‑47 Summary
of Impacts to Aquaculture Ponds from Pollution
|
Criteria
|
Remarks
|
|
Habitat Quality
|
High
|
|
Species
|
|
|
Size/abundance
|
Although there are
about 170.6 ha.
of Aquaculture ponds within the assessment area, a relatively small
proportion of these lie adjacent to the development area or in areas that
could be affected by residential development construction activities. Construction
activities within the WNR primarily involve pond re-profiling and are
unlikely to pose a significant pollution risk.
The main pollution
risk to bund vegetation is from fugitive dust during construction works. If
dust is released it is likely to affect a large area depending on its source
and prevailing wind directions.
No Aquaculture
Ponds lie adjacent to the route of sewage strategy A2 (or A1). Three
Aquaculture Ponds lie adjacent to Strategy B in the western part of the
assessment area.
|
|
Duration
|
Construction and
operation phase
The effects of
pollution are likely to be persistent, particularly if toxic chemicals are
involved or if the pollutant has a tendency to bioaccumulate
|
|
Reversibility
|
Generally
reversible although duration of recovery will depend on the nature of the
pollutant and the magnitude of the event. No highly toxic pollution events
are anticipated however
|
|
Magnitude
|
Low under
preferred sewage strategy (A2)
Potentially
moderate to large under sewage strategy B, in the event of a sewer pipe burst
|
Table
13‑48 Summary of
Impacts to Fung-shui Woodland (including Egretry) from
Pollution
|
Criteria
|
Remarks
|
|
Habitat Quality
|
Low (High if
egretry present)
|
|
Species
|
Species of
Conservation Importance, including nesting herons and egrets, could
potentially be affected
|
|
Size/abundance
|
A survey
undertaken in June 2001 indicated that the egretry possessed up to 74 nests
located within approximately 0.2
ha of the woodland. More recent inspections indicate that the
egretry has been abandoned.
The main pollution
risk to the Fung-shui Woodland
(and egretry if present) is from fugitive dust during construction works.
Potentially all of the 1.25 hectares of Fung-shui woodland is at risk from
dust pollution, although the magnitude of this risk will depend on the dust
source and prevailing wind directions.
|
|
Duration
|
Construction phase
only. Impacts that occur during the egret breeding season (if egretry
present) would be of greater magnitude
|
|
Reversibility
|
Largely reversible
– any impacts to egretry (if present) may be irreversible
|
|
Magnitude
|
Low (High if
egretry present)
|
Table 13‑49 Summary
of Impacts to Intertidal Forested Wetland from Pollution
|
Criteria
|
Remarks
|
|
Habitat Quality
|
Moderate to high
|
|
Species
|
Species of
Conservation Importance could potentially be affected
|
|
Size/abundance
|
45.3 ha. present within the Assessment Area.
The risk of
chemical pollution to this habitat is low due to its remote location from the
construction site and proposed sewer strategies.
The main pollution
risk, therefore, is fugitive dust during construction works. If dust is
released it is likely to affect a large area depending on its source and
prevailing wind directions.
|
|
Duration
|
Construction phase
only
|
|
Reversibility
|
Reversible
|
|
Magnitude
|
Moderate
|
Table 13‑50 Summary
of Impacts Wetland Mosaic Habitats (including Wet Agriculture, Reedbed, and
Freshwater Marsh) from Pollution
|
Criteria
|
Remarks
|
|
Habitat Quality
|
Low to moderate
|
|
Species
|
Species of
Conservation importance could potentially be affected
|
|
|
The small wetland
mosaic in the south-western part of the assessment area is located close to
the proposed construction site of the residential development. All of this
mosaic is potentially at risk from accidental pollution events during
construction
During operation
there is a small risk of pollution arising from contamination by sewage in
the event of a pipe burst. Neither of the strategies considered, however,
involve placing pipes in close proximity to these habitats and, in any event
the use of twinned sewage pipes ensures that any burst is controllable
|
|
Duration
|
Construction and
operation phase
The effects of
pollution are likely to be persistent, particularly if toxic chemicals are
involved or if the pollutant has a tendency to bio-accumulate
|
|
Reversibility
|
Generally
reversible although duration of recovery will depend on the nature of the
pollutant and the magnitude of the event. No highly toxic pollution events
are anticipated however and the risk of large scale pollution events due to
dust or sediment dispersal is considered low
|
|
Magnitude
|
Moderate
|
Table 13‑51 Summary
of Impacts to Dry/Inactive Agricultural Land from Pollution
|
Criteria
|
Remarks
|
|
Habitat Quality
|
Low to moderate
|
|
Species
|
No Species of
Conservation Importance are likely to be affected
|
|
Size/abundance
|
The main pollution
risk to the small areas of this habitat within the assessment area is from
fugitive dust during construction works. The magnitude of this risk will
depend on the dust source and prevailing wind directions
|
|
Duration
|
Construction phase
only
|
|
Reversibility
|
Reversible
|
|
Magnitude
|
Moderate
|
Table 13‑52 Summary
of Impacts to Semi-natural Secondary Woodland
from Pollution
|
Criteria
|
Remarks
|
|
Habitat Quality
|
Low to moderate
|
|
Species
|
No Species of
Conservation Importance are likely to be affected
|
|
Size/abundance
|
The main pollution
risk to this habitat is fugitive dust during construction works. If dust is
released it is likely to affect a large area depending on its source and
prevailing wind directions
|
|
Duration
|
Construction phase
only
|
|
Reversibility
|
Reversible
|
|
Magnitude
|
Moderate
|
Soil Compaction
13.8.23
The use of heavy machinery
during construction works could result in the compaction of soils on the bunds
associated with the existing aquaculture pond bunds.
Table 13‑53 Summary of Impacts to Aquaculture Ponds from Soil Compaction
|
Criteria
|
Remarks
|
|
Habitat Quality
|
High
|
|
Species
|
No Species of
Conservation Importance likely to be affected
|
|
Size/abundance
|
Potentially
affects those pond bunds that will not be removed during construction within
the development area and conversion of aquaculture ponds to freshwater marsh.
A large proportion
of the remaining pond bunds could be affected by soil compaction associated
with the use of heavy machinery during the removal and modification of pond
bunds associated with pond enhancement works
|
|
Duration
|
Construction phase only
|
|
Reversibility
|
Reversible
|
|
Magnitude
|
Low
|
Hydrological disruption
13.8.24
The proposed development will
involve the diversion of some existing Ditches and Drainage Channels. As these
habitats were found to be of low quality and the extent of habitat affected is
low, the impact of hydrological diversion to this habitat is also considered to
be low.
Table 13‑54 Summary of Impacts to Ditches and Drainage Channels from Hydrological Disruption
|
Criteria
|
Remarks
|
|
Habitat Quality
|
Low
|
|
Species
|
The drainage
channels on site are of low water quality and support no Species of
Conservation Importance
|
|
Size/abundance
|
Approximately 0.02
hectares will be removed and a short stretch will be diverted. Remaining
stretches will be used to manage water levels within the proposed WNR
|
|
Duration
|
Permanent
|
|
Reversibility
|
Impact is
irreversible
|
|
Magnitude
|
Low
|
Summary of Potential Impacts on Habitats
During Construction
13.8.25
There will be no net loss of
water body in the WCA or WBA. Permanent habitat loss of aquaculture ponds due
to the development footprint will be compensated by re-profiling aquaculture
ponds, thus creating enlarged ponds of higher ecological value, and freshwater
marsh, also of higher ecological value. The pond enhancement works are likely
to cause some compaction of bunds during construction activities, particularly
in relation to the removal and modification of bunds during the WNR development.
The significance of this impact is, however, considered to be low in light of
the low intrinsic value of bunds within the aquaculture pond habitat.
13.8.26
No significant habitat
fragmentation is anticipated as a consequence of the proposed development. The
potential for obstruction of flightlines of any herons and egrets that may nest
at the egretry at Shing Uk Tsuen (now apparently abandoned) is considered under
Impacts on Species of Conservation Importance below
13.8.27
The major effect of disturbance
caused by construction of the proposed development will be on sensitive bird
species. During construction, areas of Aquaculture Pond habitat close to the
Proposed Development Area are expected to support significantly reduced
populations of wetland Species of Conservation Importance, this potential
impact is considered in more detail under Impacts on Species of Conservation
Importance below.
13.8.28
There is a potential risk of
pollution to some habitats through, for example, accidental releases of
chemicals or dust during construction. The habitats most at risk from
accidental release of pollutants such as fuel or chemicals are those in the
immediate vicinity of the development area or that are linked to the
development area hydrologically. These include Aquaculture Ponds, Drainage
Ditches and Channels and Wetland Mosaic Habitats (including Wet Agriculture,
Reedbed, and Freshwater Marsh).
13.8.29
Most habitats within the
assessment areas are at some risk from the effects of fugitive dust created
during construction activities, including, potentially, Aquaculture Ponds,
Intertidal Forested Wetland and Fung-shui Woodland.
The potential impacts of smothering from dust are considered to be moderate
because, whilst they may be locally intense, they are also temporary in nature
and reversible.
13.8.30
During construction the
potential effects of Options 1A
and 1B are considered to be the same.
Summary of Potential Impacts on Habitats
During Operation
13.8.31
The key potential impacts
associated with the operational phase of the development include disturbance,
habitat fragmentation and pollution arising from operation of the sewerage
system.
13.8.32
During operation areas of
Aquaculture Pond habitat close to the Proposed Development Area are expected to
support significantly reduced populations of wetland Species of Conservation
Importance, due to disturbance caused by human presence, noise and lighting.
This potential impact is considered in more detail under Impacts on Species of
Conservation Importance below.
13.8.33
The presence of tall built
structures could obstruct flightlines of birds, particularly herons and egrets
and reduce accessibility to important feeding areas. This potential impact is
considered in more detail under Impacts on Species of Conservation Importance
below.
13.8.34
The risk of pollution from the
operation of the sewerage system is considered to be low. Under the preferred
strategy (A2) new sewer pipes will follow existing roads, furthermore the use
of twinned pipes will ensure that the possibility of significant leakage is
minimised in the event of a pipe burst. Under strategy B the same precautions
would be taken but the proximity of the pipe route to sensitive Aquaculture
Pond habitat means that the consequences of a leak, although unlikely, would be
more significant.
13.8.35
In the event of an emergency
by-pass of the sewage pump house, sewage would be directed to the Tai River
via a pipe to Channel X. Although this would avoid disposing of untreated
sewage to sensitive habitats within the WNR, there would be short-term
intensive impact to a short stretch of Ditches and Drainage Channel habitat, a
habitat of low intrinsic value. There would also be a temporary impact to the Tai River (Permanent Rivers, Streams and Creeks habitat).
Dilution effects, the existing poor water quality of the Tai River
and the expected short duration of by-pass events ensure, however, that
long-term significant impact to this habitat is unlikely.
13.8.36
The potential effects of
Options 1A and 1B
during the operational phase are considered to be similar in many respects, the
only slight difference between these two options arising from the larger number
of buildings in Option 1B. The gaps between buildings will be smaller in this
option creating a slightly greater blockage of sightlines for birds. It is
predicted, therefore, that Option 1B will result in slightly greater habitat
fragmentation than Option 1A.
It is emphasised that the difference between these options is slight,
particularly in light of the abandonment of the egretry, as it was the
potential blockage of flights to and from this feature that was the principal
source of concern with respect to habitat fragmentation.
Assessment of Potential Impacts on
Species of Conservation Importance
13.8.37
The assessment of impacts on
habitats above indicates that there are effects arising from the construction
and operation of the proposed development that will have an impact on animal
species, in particular:
·
Habitat loss;
·
Disturbance caused by the
construction and operation of the proposed development, including mitigation
associated with the construction of the Wetland Nature Reserve (WNR). In order
to minimise the effects of habitat loss and disturbance key works associated
with the WNR will be undertaken before the commencement of construction of the
residential development. The potential disturbance associated with these works
is also considered in this section; and,
·
Fragmentation – in particular
the obstruction of flightlines of birds moving to and from the egretry.
Habitat Loss
13.8.38
It is anticipated that the key
habitat likely to be directly affected by the proposed residential development
is Aquaculture Ponds. It is predicted that approximately 4.0 ha of aquaculture ponds will be
permanently lost within the Development Area. In addition there will be
temporary habitat loss during the construction of the WNR arising from:
·
Construction of the Marsh
Habitat and the approximately 1 year of establishment required for this habitat
(approximately 14.4 ha).
·
Enlargement of ponds, which
will involve the simultaneous temporary drainage of 2 or 3 ponds to enable bund
removal and re-profiling.
13.8.39
The relative timing of the
construction of the key elements of the WNR and the residential development is
shown in Figure
13‑13. The construction of the WNR is divided into Sectors
as described in Section 13.9. At each stage the maximum area of pond
unavailable due to construction works is shown along with the remaining area
unaffected by construction works. During construction the period during which
the most area is unavailable (approximately 22.2 ha) is between April 2011 and October 2011 when the Development Area, the Marshland
(which will be establishing) and some Sector 3 ponds will be concurrently
unavailable. This represents a maximum temporary loss of approximately 28% of
the total wetland habitat present within the Study Site.
13.8.40
The species most likely to be
affected by permanent and temporary habitat loss are birds, particularly
waterbirds. It is envisaged that there will be adequate remaining wetland
within the Study Area, and adjacent areas, to accommodate birds permanently
displaced from the Development Area (which represent approximately 5% of the
total wetland area within the Study Site) and temporarily displaced from the
Aquaculture Ponds and WNR construction areas. To ensure that the carrying
capacity of the remaining wetland areas is sufficient for these species an
interim management programme will be implemented intended to significantly
improve feeding opportunities for waterbirds, particularly ardeids (see below).
13.8.41
It is anticipated that
permanent and temporary habitat loss will reduce the availability of foraging
habitat for Imperial Eagle, Great Spotted Eagle and Osprey. The significance of
this impact is considered to be low due to the scarcity of these species at Fung
Lok Wai and their large foraging ranges. This conclusion is reached on the
basis of the following:
1)
During the 12 months baseline
survey there were very few records of these species within the survey area. In
fact there were no records of Great Spotted Eagle or Osprey utilising habitats
within the proposed areas for the Residential Development nor the WNR. These
species were either observed overflying the general Fung Lok Wai area or were
observed within the wider assessment area (ie within the 500m buffer around the EIA study area WNR).
It is clear, therefore, that the 12 months survey did not find any evidence
that these species have any particular reliance upon the ponds potentially
affected by the proposed Residential Development or WNR. As indicated for other
species there is no indication that the importance of these ponds would have
increased in importance during the period since the 12 months survey was
undertaken (see Appendix 13-12).
2)
To the extent that Imperial
Eagle, Great Spotted Eagle and Osprey are likely to forage within the study
area, then it has been assumed in the EIA report that noise and human presence
will cause disturbance during construction and operation. The magnitude of the
displacement effect arsing from this disturbance is evaluated in Table 13‑56 (construction) and Table
13‑57(operation) (see below). For the purpose of these
evaluations it has been assumed that raptors are amongst the most sensitive
species present and that any effect would detectible upto 500m from the source of disturbance. These tables, in
summary, indicate that the maximum area of habitat affected would be 51.4 ha during construction and
operation for each of the three species. As indicated above though this represents
displacement from an area upon which these species show little reliance.
3)
The effect of this displacement
on Imperial Eagle, Great Spotted Eagle and Osprey is not considered to be of
anything other than low significance because:
·
None of these species shows
great reliance upon the habitats potentially affected
·
There is extensive alternative
habitat for these species within the New
Territories – all three
species forage over large areas. EPD indicate that the extent of freshwater
wetland in Hong Kong is approximately 10,000ha and the area affected by this
development, therefore, represents about 0.5%. This does not take account of
inter-tidal habitats that these species may also rely upon.
·
The mitigation proposed for the
construction and operational phases aims, in any case, to increase the numbers
of wetland birds within those areas that are not affected by operational
disturbance. This will include waterfowl that comprise prey for the eagle
species and fish, that are preyed upon by Osprey.
13.8.42
Crested Serpent Eagle is less
dependent on wetland habitats than the other raptor species recorded. The significance of permanent and temporary
habitat loss for Crested Serpent Eagle is, therefore, considered to be very
low.
13.8.43
It is considered that the
impacts of both Options 1A and 1 B will be similar with respect to habitat loss
for these raptor species.
13.8.44
There are several Species of
Conservation Importance that are dependent on bund habitats, the most important
of which are, Red-billed Starling, Collared Crow and Cattle Egret. The
development of the WNR will result in the removal of some bunds (as indicated
in Figure
14‑6). The potential impact of bund removal on these
species is considered to be of low magnitude, however, for the following
reasons:
·
Red-billed Starling and
Collared Crowe were recorded in relatively low numbers within the study site.
Extent of bund habitat is unlikely to be the key limitiation on the population
size of these species.
·
Cattle Egret were recorded in
highest numbers in the north-western part of the study site on ponds that are
adjacent to the Tai River, the location where there would be no bund removal works (see Figure
14‑6).
13.8.45
The other Species of
Conservation Importance potentially affected by the construction of the
Residential Development and the WNR are reptiles. The effects on these species
are considered to be of low magnitude because:
·
The works will be undertaken
progressively ensuring that the area affected at any one time is relatively
small.
·
There are abundant areas of
alternative habitat for these species.
·
The baseline surveys
established that the key areas of importance for these species tended to be
located in the buffer zone (ie outside the Development Area and location of the
WNR).
13.8.46
It is considered that the
impacts of both Options 1A
and 1 B will be similar with respect to habitat loss for all Species of
Conservation Importance.
Disturbance
13.8.47
Disturbance can arise from
works associated with the construction of the Residential Development and the
WNR. In addition it is anticipated that there will be disturbance arising from
the ongoing operation of the Residential Development, although this is expected
to be of a lesser magnitude than that arising from construction activities. The
operation of the WNR is expected to be beneficial for Species of Conservation
Importance
13.8.48
The species most likely to be
affected by disturbance impacts are Species of Conservation Importance birds
(particularly flock feeding waterbirds, larger herons and birds of prey), and
to less of an extent, reptiles. Such species are likely to be disturbed by loud
noises, moving objects, the presence of people, glare from reflective surfaces
and night-time lighting. Stationary objects such as buildings are also sources
of disturbance as these may obscure flight lines and views of potentially
approaching predators. Other species that could be affected are mammals.
However, no large mammals were recorded during the field surveys and therefore
particular attention will be focussed on bird Species of Conservation
Importance recorded on site.
13.8.49
An assessment of the predicted
impacts of disturbance on each Species of Conservation Importance that
regularly occurs in significant numbers has been carried out. The assessment is
based on a combination of literature review, analysis of field survey data and
experience of the study team and previously accepted assessment criteria. The
magnitude of disturbance effects, including night-time glare, has been evaluated
on the basis of disturbance distances. It has been assumed that disturbance
effects (including night-time glare) will result in a zone around the
residential development where sensitive species will: a) be excluded; and b)
occur in reduced densities. The effects of night glare are integrated into the
assessment because it is assumed that the extent of the exclusion or reduced
density zones will be maintained through the day and night (24hrs). During the
day noise and human presence are expected to be the main disturbance factors,
at night light will be a factor. As light will not be directed into the WNR,
there is no reason to believe that the magnitude of light glare would exceed
that of day-time disturbance effects. In fact, there is evidence that artificial
light can benefit some birds, including waders. Wading birds that feed by
sight, for example, use artificial illumination of foraging habitats to extend
the period within which they able to forage. Disturbance impacts have been
calculated by defining distance from the edge of the disturbance source to the
furthest point of:
·
An exclusion zone – the area
adjacent to the source of disturbance and from which a species are expected to
be completely excluded; and
·
A zone of reduced density –
Where the numbers of a species are lower than they would be in the absence of
disturbance either because it occurs in lower numbers (more tolerant
individuals) and/or for a shorter period of time (for example during periods of
reduced human activity).
13.8.50
The distances at which these
effects occur vary from species to species, depending on their sensitivity as
indicated in Table 13‑53.
13.8.51
Subsequent assessments of
disturbance effects on Species of Conservation Importance are based on the
extent of habitat loss, or functional habitat loss, arising because species are
excluded from, or occur in reduced densities within, habitats that would be
otherwise suitable for them. The extent functional habitat loss will be greater
for more sensitive species than it is for species that are considered to
disturbance tolerant. The extent of functional habitat loss has been calculated
by assuming that the utilisation of habitats within the exclusion zone is 0%.
In other words the functional habitat loss in this zone is 100%. Beyond this,
in the zone of reduced density, utilisation is considered to be 50% of that
within undisturbed areas (based on the assumption that there will be 0%
utilisation at the border with the avoidance zone rising to 100% utilisation at
the border with the undisturbed areas). The overall extent of functional
habitat loss is, therefore, calculated by adding 100% of the area within the
exclusion zone + 50% of the area within the zone of reduced density. The extent
of habitats affected in this way have been calculated using GIS.
13.8.52
This approach is used because
it provides an integrated way of considering all disturbance effects,
including, for example, noise, human presence, day-time glare and night-time
lighting effects. The approach is conservative because the disturbance
distances are considered to be cautious.
13.8.53
The predicted disturbance
distance for regularly occurring Species of Conservation Importance are shown
in Table 13‑55 and presented in Figure
13‑12.
Table 13‑55 Predicted Disturbance Impacts from the Construction and
Operation of the Residential Development on Regularly Occurring Species of
Conservation Importance at Fung Lok Wai
|
|
Construction phase
|
Operation phase
|
Sensitivity to disturbance
|
|
|
Exclusion distance (m)
|
Max distance of reduced density (m)
|
Exclusion distance (m)
|
Max distance of reduced density (m)
|
|
Black-faced Spoonbill
|
200
|
400
|
100
|
200
|
High
|
|
Greater Spotted Eagle
|
200
|
500
|
200
|
500
|
Very High
|
|
Imperial Eagle
|
200
|
500
|
200
|
500
|
Very High
|
|
Red-billed Starling
|
100
|
200
|
50
|
100
|
Moderate
|
|
Common Teal
|
100
|
300
|
50
|
100
|
Moderate-High
|
|
Eurasian Wigeon
|
100
|
300
|
50
|
100
|
Moderate-High
|
|
Osprey
|
200
|
500
|
200
|
500
|
Very High
|
|
Black Kite
|
50
|
100
|
20
|
30
|
Low
|
|
Chinese Pond Heron
|
100
|
300
|
20
|
30
|
Moderate
|
|
Great Cormorant
|
200
|
400
|
100
|
150
|
High
|
|
Great Egret
|
200
|
400
|
100
|
200
|
High
|
|
Little Egret
|
100
|
400
|
20
|
100
|
Moderate-High
|
|
Black-crowned Night Heron
|
50
|
100
|
20
|
30
|
Low
|
|
Cattle Egret
|
50
|
100
|
20
|
30
|
Low
|
|
Grey Heron
|
100
|
300
|
20
|
30
|
Moderate
|
|
Striated Heron
|
100
|
300
|
20
|
30
|
Moderate
|
|
Collared Crow
|
50
|
100
|
20
|
30
|
Low
|
|
Crested Serpent Eagle
|
200
|
500
|
200
|
500
|
Very High
|
|
Little Grebe
|
100
|
200
|
50
|
50
|
Moderate-High
|
|
Little Ringed Plover
|
100
|
200
|
50
|
50
|
Moderate-High
|
|
Pied Kingfisher
|
50
|
100
|
20
|
30
|
Low
|
|
Temminck’s Stint
|
100
|
200
|
50
|
50
|
Moderate-High
|
|
White-throated Kingfisher
|
50
|
100
|
20
|
30
|
Low
|
|
Wood Sandpiper
|
100
|
200
|
50
|
50
|
Moderate-High
|
13.8.54
Analysis of the susceptibility
of Species of Conservation Importance to disturbance above indicates that four species
of raptor Imperial Eagle, Greater Spotted Eagle, Osprey and Crested Serpent
Eagle and three species of large waterbird, Black-faced Spoonbill, Great
Cormorant and Great Egret are most susceptible.
13.8.55
Of these species, the four
birds of prey range widely in the Deep
Bay area and are known to
exhibit marked avoidance of man-made structures. Single individuals of Imperial
Eagle, Greater Spotted Eagle, Crested Serpent Eagle and Osprey were
recorded flying over Fung Lok Wai on a maximum of three occasions throughout
the twelve months of survey and hence are not considered likely to have a
significant dependence on the site. In addition results of a recent survey of
Imperial and Greater Spotted Eagle (KCRC & BBVHK 2002) indicate that these
species have a significant preference for managed wetland (e.g. Mai Po) and neither showed a
significant preference for fishpond habitat.
13.8.56
The key habitat for the
remaining species within the assessment area are Aquaculture Ponds.
13.8.57
Construction activity
associated with the Residential Development will commence during the second
half of 2013. The construction of the residential development will result in the
permanent loss of approximately 4.0 ha
of aquaculture ponds. During the early stages of construction the created
Freshwater Marsh habitat will not be fully established and this area
(approximately 14.4 ha)
is also assumed to be temporarily unavailable.
13.8.58
In addition, it is anticipated
that disturbance caused, primarily by human presence, noise and vibration
during the construction of the residential development will result in a reduced
density of birds adjacent to the development. The maximum distance of reduced
density (as indicated in Table
13‑55) is expected to be 500m for the most sensitive Species of Conservation
Importance (for example, Osprey) and 100m
for the least sensitive (including, for example, White-throated Kingfisher).
The additional temporary habitat loss caused by construction activities
associated with the construction of the residential development will range,
therefore, between approximately 33.0
ha and 2.0 ha
depending on the sensitivity of the species. Taking into account the loss of
approximately 4.0ha
due to the construction of the Residential Development and the temporary unavailability
of approximately 14.4 ha
during construction of the Freshwater Marsh area, this amounts to between 51.4 ha and 20.4 ha, respectively. It should be noted, however,
that these figures are considered to be over-estimates. It is unlikely that
development will proceed in all parts of the development area simultaneously
reducing the area affected by disturbance at any one time.
13.8.59
Table 13‑56 identifies the permanent and temporary habitat loss
during the construction phase for each of the regularly occurring Species of
Conservation Importance. These impacts have been calculated on the assumption
that there will be low level visual human disturbance and that basic mitigation
measures, including the creation of wetland habitats with reedbeds and the
planting of trees and bamboo as screening will be implemented.
Table 13‑56 Habitat Loss During the
Construction Phase on Regularly Occurring Species of Conservation Importance at
Fung Lok Wai
|
Species
|
Maximum distance of reduced density during
construction (m)
|
Permanent habitat loss (ha)
|
Temporary habitat loss due to marsh construction
(ha)
|
Temporary habitat loss due to construction
disturbance (ha)
|
Maximum area of habitat affected (ha)
|
|
Black-faced Spoonbill
|
400
|
4.0
|
14.4
|
23.4
|
41.8
|
|
Greater Spotted Eagle
|
500
|
4.0
|
14.4
|
33.0
|
51.4
|
|
Imperial Eagle
|
500
|
4.0
|
14.4
|
33.0
|
51.4
|
|
Red-billed Starling
|
200
|
4.0
|
14.4
|
6.4
|
24.8
|
|
Common Teal
|
300
|
4.0
|
14.4
|
12.0
|
30.4
|
|
Eurasian Wigeon
|
300
|
4.0
|
14.4
|
12.0
|
30.4
|
|
Osprey
|
500
|
4.0
|
14.4
|
33.0
|
51.4
|
|
Black Kite
|
100
|
4.0
|
14.4
|
2.0
|
20.4
|
|
Chinese Pond Heron
|
300
|
4.0
|
14.4
|
12.0
|
30.4
|
|
Great Cormorant
|
400
|
4.0
|
14.4
|
23.4
|
41.8
|
|
Great Egret
|
400
|
4.0
|
14.4
|
23.4
|
41.8
|
|
Little Egret
|
400
|
4.0
|
14.4
|
19.9
|
38.3
|
|
Black-crowned Night Heron
|
100
|
4.0
|
14.4
|
2.0
|
20.4
|
|
Cattle Egret
|
100
|
4.0
|
14.4
|
2.0
|
20.4
|
|
Grey Heron
|
300
|
4.0
|
14.4
|
12.0
|
30.4
|
|
Striated Heron
|
300
|
4.0
|
14.4
|
12.0
|
30.4
|
|
Collared Crow
|
100
|
4.0
|
14.4
|
2.0
|
20.4
|
|
Crested Serpent Eagle
|
500
|
4.0
|
14.4
|
33.0
|
51.4
|
|
Little Grebe
|
200
|
4.0
|
14.4
|
6.4
|
24.8
|
|
Little Ringed Plover
|
200
|
4.0
|
14.4
|
6.4
|
24.8
|
|
Pied Kingfisher
|
100
|
4.0
|
14.4
|
2.0
|
20.4
|
|
Temminck’s Stint
|
200
|
4.0
|
14.4
|
6.4
|
24.8
|
|
White-throated Kingfisher
|
100
|
4.0
|
14.4
|
2.0
|
20.4
|
|
Wood Sandpiper
|
200
|
4.0
|
14.4
|
6.4
|
24.8
|
13.8.60
Once construction of the
residential development is complete it is anticipated that there will be
ongoing disturbance, at a significantly reduced level, associated with the
operation of the site.
13.8.61
For the purposes of this
assessment the operational phase disturbance impact has been estimated on the
basis of the disturbance distances (operation phase) in Table 13‑53 The distances of reduced density are considered to be
lower for the key species listed than during the construction phase. This is
because:
·
The intensity of noise and vibration
during ongoing use are expected to be much lower than during construction which
requires the use of heavy machinery;
·
Noise and vibration tend to be
more continuous than during construction and some level of habituation is
expected; and,
·
There will be screening at
ground level reducing the visibility of residents to birds within the WNR.
13.8.62
In addition it has been assumed
that the area of the residential development (4.0
ha) is unavailable and that the created marsh habitat (c.
14.4 ha) will continue to be unavailable. In practice though it
is expected that the marsh habitat will be fully established by the time that
the development is occupied and will provide additional habitat for the Species
of Conservation Concern potentially affected by disturbance effects.
Consequently the following assessment of disturbance impacts during operation
is highly precautionary. The expected habitat loss predicted during the
operation phase is indicated in Table
13‑57.
Table 13‑57 Habitat Loss during the
Operation Phase on Regularly Occurring Species of Conservation Importance at
Fung Lok Wai
|
Species
|
Operation phase max distance of reduced density (m)
|
Permanent habitat loss (ha)
|
Temporary habitat loss during marsh establishment (ha)
|
Functional habitat loss due to operational disturbance (ha)
|
Total (ha)
|
|
Black-faced Spoonbill
|
200
|
4.0
|
14.4
|
6.4
|
24.8
|
|
Greater Spotted Eagle
|
500
|
4.0
|
14.4
|
33.0
|
51.4
|
|
Imperial Eagle
|
500
|
4.0
|
14.4
|
33.0
|
51.4
|
|
Red-billed Starling
|
100
|
4.0
|
14.4
|
2.0
|
20.4
|
|
Common Teal
|
100
|
4.0
|
14.4
|
2.0
|
20.4
|
|
Eurasian Wigeon
|
100
|
4.0
|
14.4
|
2.0
|
20.4
|
|
Osprey
|
500
|
4.0
|
14.4
|
33.0
|
51.4
|
|
Black Kite
|
30
|
4.0
|
14.4
|
0.8
|
19.2
|
|
Chinese Pond Heron
|
30
|
4.0
|
14.4
|
0.8
|
19.2
|
|
Great Cormorant
|
150
|
4.0
|
14.4
|
4.5
|
22.9
|
|
Great Egret
|
200
|
4.0
|
14.4
|
6.4
|
24.8
|
|
Little Egret
|
100
|
4.0
|
14.4
|
1.8
|
20.2
|
|
Black-crowned Night Heron
|
30
|
4.0
|
14.4
|
0.8
|
19.2
|
|
Cattle Egret
|
30
|
4.0
|
14.4
|
0.8
|
19.2
|
|
Grey Heron
|
30
|
4.0
|
14.4
|
0.8
|
19.2
|
|
Striated Heron
|
30
|
4.0
|
14.4
|
0.8
|
19.2
|
|
Collared Crow
|
30
|
4.0
|
14.4
|
0.8
|
19.2
|
|
Crested Serpent Eagle
|
500
|
4.0
|
14.4
|
33.0
|
51.4
|
|
Little Grebe
|
50
|
4.0
|
14.4
|
1.1
|
19.5
|
|
Little Ringed Plover
|
50
|
4.0
|
14.4
|
1.1
|
19.5
|
|
Pied Kingfisher
|
30
|
4.0
|
14.4
|
0.8
|
19.2
|
|
Temminck’s Stint
|
50
|
4.0
|
14.4
|
1.1
|
19.5
|
|
White-throated Kingfisher
|
30
|
4.0
|
14.4
|
0.8
|
19.2
|
|
Wood Sandpiper
|
50
|
4.0
|
14.4
|
1.1
|
19.5
|
13.8.63
In the absence of mitigation,
the potential impacts of the proposed development on Species of Conservation
Importance due to habitat loss and disturbance are likely to be significant.
The magnitude of these impacts is greatest during construction but the effects
will be temporary. During operation the magnitude of impacts on Species of
Conservation Importance is less but the effects will be permanent, although
over time it is expected that bird populations will habituate to disturbance to
some extent.
13.8.64
A key aspect of this
proposal is the construction of a WNR to compensate for impacts associated with
habitat loss and disturbance. The strategy, programme and specific actions
associated with the construction and operation of the WNR are addressed in
detail in Section 13.9 (Mitigation). That section also identifies likely
disturbance effects that potentially arise from the construction of the WNR
itself.
13.8.65
It is considered that the
disturbance impacts on birds (including raptors) and other wildlife arising
from both Options 1A and 1 B will be the same.
Habitat Fragmentation
13.8.66
The impact of any development
on bird flight lines is unclear. Birds are extremely mobile and will
undoubtedly seek to avoid obstructions. Furthermore, the construction time for
a high rise development is typically in the order of months to years providing
opportunity for birds, even those that may have habituated to flying certain
routes, to find alternative flight lines to foraging or roosting sites.
13.8.67
Surveys of bird flightlines
undertaken during the baseline study indicated that the proposed development
was in-line with a small proportion of flight paths of birds moving to and from
the egretry at Shing Uk Tsuen (located to the south-west of the Study Site).
More recent observations now indicate that this egretry has been abandoned
(Anon 2005) eliminating potential impacts on this feature. In addition the
in-filling of ponds required to enable the construction will reduce flight
activity in the area of the proposed Residential Development due to the removal
of foraging opportunities in that area (see impacts associated with habitat
loss and disturbance).
13.8.68
Analysis of data collected when
the egretry was occupied indicated that approximately 24% of observed
flightlines originating from, or terminating at, the egretry passed through the
zone occupied by the current Proposed Development Area (Figure 13‑11).
13.8.69
Comparison of alternative
development options (see section 13.6 above) indicated that it was possible to
reduce the potential impact of the residential development on these flightlines
by shifting the Development Area eastwards. As a consequence a decision was
taken to move the development 150m
eastwards of its original location, leading to a reduction in flightline
intersection from 65% to 24%. The relocated development area is at the
periphery of the study site and does not now, in the absence of the egretry,
lie between areas of habitat that are important for waterbirds.
13.8.70
Additionally the following
mitigation is also intrinsic to the design of the development:
·
Adoption of a building design
that emphasises fewer taller buildings (consistent with height constraints)
rather than many smaller buildings. This enables gaps to be maintained between
buildings preserving sight lines for birds moving within the site.
·
Construction of a potential
alternative egretry within the WNR. The provision of this feature will
encourage any nesting birds to occupy a site that is within the central part of
the fishpond area, thus potentially eliminating the need for flights through
the development area. It should be noted that there is no precedent for the
re-establishment of egretries that have been abandoned in Hong
Kong (G. Carey, pers comm.).
13.8.71
The results of the flightline
surveys (see Table 13‑33 and Table
13‑34) indicate that, other than ardeids, there were few
flightlines arising from other species passing through the proposed area of the
Residential Development. On this basis it is considered that there is no
indication that there would be a significant fragmentation effect on any bird
species arising from the construction and operation of the Residential
Development.
13.8.72
A potential additional effect
of the construction of mid-rise buildings relates to the obstruction of sight
lines. This would occur if buildings prevented birds seeing habitats that might
otherwise seek to forage within. This is primarily likely to affect Greater
Spotted Eagle and Imperial Eagle which are likely to perch on higher ground (as
found to the south of Fung Lok Wai) prior to foraging over wetland areas. This
effect is likely to be of lesser importance for Crested Serpent Eagle which is
less reliant on wetland habitats than Greater Spotted Eagle and Imperial Eagle.
It is of least importance to Osprey which does not typically seek out higher
ground for any purpose.
13.8.73
The significance of the
potential impact arising from the blockage of sight lines is considered to be
low for Greater Spotted Eagle and Imperial Eagle due to their demonstrated low
reliance upon the wetland habitats at Fung Lok Wai. It should be noted that
baseline ornithological surveys included hillside habitats (Transect 6) and
raptors (including the eagle species) were rarely recorded in this area.
13.8.74
With respect to Crested Serpent
Eagle and Osprey the potential effect is considered to be insignificant due to
the behaviour of these species which implies that sightline blockage will be
negligible.
13.8.75
Although both Option 1A and 1B involve the construction of
mid-rise buildings, there will be a greater number of more closely spaced
buildings in Option 1B than in Option 1A.
Conversely the buildings in Option 1A
will be slightly higher (14-18 stories) than those proposed in Option 1B (all
15 stories). It is considered that the effects of reducing the spacing of
buildings will reduce sightlines to a greater extent than the slight
differences in building height proposed. On this basis it is concluded that
Option 1B will have a slightly greater impact, with respect to this effect,
than Option 1A. It should
be noted, however, that the potential impact of both options is considered to
be low for Greater Spotted Eagle and Imperial Eagle and insignificant for
Osprey and Crested Serpent Eagle.
13.8.76
In light of the relocation of
the development, the abandonment of the Shing Uk Tsuen egretry, the proposed
mitigation and the likely reduction in flight activity within the proposed
Residential Development Area once the existing ponds have been in-filled (to
enable construction), it is anticipated that the effect of flightline
obstruction will be minor. In Option 1B the gaps between buildings will be
smaller than in Option 1A
creating a slightly greater blockage of sightlines for birds. It is predicted,
therefore, that flightline obstruction (and hence habitat fragmentation) in
Option 1B will be slightly greater than in Option 1A. It is emphasised, however, that the difference
between these options is slight, particularly in light of the abandonment of
the egretry, as it was the potential blockage of flights to and from this
feature that was the principal source of concern.
13.8.77
There is no indication that the
construction of the residential development would result in the fragmentation
of the habitat for any animal species (other than birds). The location of the
development, at the periphery of the wetland area, will not create a barrier to
the movement of wildlife associated with wetland habitats (or any other habitat
type). In this resect there is no difference between Options 1A or 1B and both are considered to have an
insignificant impact with respect to habitat fragementation for non-avian
species.
13.8.78
Another potential source of
fragmentation that could affect Species of Conservation Importance is the
erection of fencing around the perimeter of the site and the erection of works
area hoarding around construction areas.
13.8.79
Perimeter fencing will comprise
a chain link fence to prevent unauthorised access to the site. The fence will
not be a completely impervious barrier to wildlife, there will be gaps
associated with access routes and small animals, such as reptiles and
amphibians are expected to pass through the fence unhindered. Birds will be
able to pass over the fence and, as it is chain link, it will not obstruct site
lines. There is potential, however, for the fence to obstruct the movement of
medium and large mammals, such as Eurasian Otter (Lutra lutra) and Crab-eating Mongoose (Herpestes urva).
13.8.80
Neither species was observed
during the baseline surveys, but they are known to be present in similar
habitats in the Deep
Bay area. Whilst there is
potential for fencing around the site to obstruct the movement of species such
as these, the magnitude of this impact is not expected to be high as existing
security fencing to the north-west and north-east of the site (along the banks
of the Shan Pui River) has already effectively isolated Fung Lok Wai from
potential adjacent habitats for these species. Nevertheless some reduced
movement of medium to large mammal species is anticipated between Fung Lok Wai
and adjacent habitats due to perimeter fencing.
13.8.81
The erection of works area
hoarding is not anticipated to cause impact to wildlife by obstructing movement
as it will be located around areas within which construction is taking place
and which are not expected (once works commence) to provide habitat for any
Species of Conservation Importance.
Other Species
13.8.82
Five non-bird Species of Conservation Importance
were identified in low numbers within the Assessment Area, Banded Krait, Common
Rat Snake, Indo-Chinese Rat Snake, Many-banded Krait and Mangrove Water Snake
(see section 13.6). Of these Common Rat Snake (Ptyas mucosus), Indo-Chinese Rat Snake (Ptyas korros) and Mangrove Water Snake are expected, on the basis
of their habitat preferences and baseline survey data, to have the greatest
reliance on the area of fishponds that will be enhanced during construction of
the Wetland Nature Reserve. The other snake Species of Conservation Importance
tended to show a greater preference for mangrove, hillside and agricultural
habitats that will be unaffected by the proposed development.
13.8.83
The sensitivity of reptile Species of Conservation Importance is not
known. It is expected that these species will avoid areas close to the
development area where there is increased human presence and the effects of
noise and vibration are likely to be greatest. Given the low observed abundance
of these species it is expected, however, that individuals affected by
disturbance can readily relocate to other parts of Fung Lok Wai and adjacent
suitable habitat that is also present within the 500m Buffer Zone.
Summary of Potential Impacts on Species
of Conservation Importance
13.8.84
The key potential impacts on
Species of Conservation Importance arising from construction and operation of
the Residential Development are permanent and temporary habitat loss. These
impacts arise from the permanent conversion of ponds within the Proposed
Development Area and disturbance caused by noise and vibration created during
construction activities in the first instance and then noise and increased
human presence during the occupation (operation) of the development in the
long-term. The Species of Conservation Importance most affected by these
impacts are expected to be birds. Reptiles, observed to be present only in low
numbers, are unlikely to be significantly affected. A summary of the
significance of potential impacts on Species of Conservation Importance are
presented in Table
13‑58.
Table 13‑58 Significance of impacts on
Species of Conservation Importance at Fung Lok Wai
|
Species of Conservation Interest
|
Evaluation
|
|
Common Name
|
Scientific Name
|
Construction Phase Impacts
|
Operation Phase Impacts
|
|
Avifauna
|
|
Black-faced Spoonbill
|
Platalea minor
|
High
|
Moderate
|
|
Greater Spotted Eagle*
|
Aquila clanga
|
Low
|
Low
|
|
Imperial Eagle*
|
Aquila heliaca
|
Low
|
Low
|
|
Red-billed Starling
|
Sturnus sericeus
|
Low
|
Low
|
|
Common Teal
|
Anas crecca
|
Low
|
Very
Low
|
|
Eurasian Wigeon
|
Anas Penelope
|
Moderate
|
Low
|
|
Osprey*
|
Pandion haliaetus
|
Low
|
Low
|
|
Black Kite
|
Milvus migrans
|
Low
|
Low
|
|
Chinese Pond Heron
|
Ardeola bacchus
|
Moderate
|
Moderate
|
|
Great Cormorant
|
Phalacrocorax carbo
|
High
|
Low
to moderate
|
|
Great Egret
|
Egretta alba
|
High
|
Moderate
|
|
Little Egret
|
Egretta garzetta
|
High
|
Moderate
|
|
Black-crowned Night Heron
|
Nycticorax nycticorax
|
Low
|
Low
|
|
Cattle Egret
|
Bubulcus ibis
|
Low
to moderate
|
Low
to moderate
|
|
Grey Heron
|
Ardea cinerea
|
Moderate
|
Moderate
|
|
Striated Heron
|
Butorides striatus
|
Very Low
|
Very Low
|
|
Collared Crow
|
Corvus torquatus
|
Very low
|
Low
|
|
Crested Serpent Eagle*
|
Spilornis cheela
|
Low
|
Low
|
|
Little Grebe
|
Tachybaptus ruficollis
|
Low
|
Low
|
|
Little Ringed Plover
|
Charadrius dubius
|
Low
|
Low
|
|
Pied Kingfisher
|
Ceryle rudis
|
Very
Low
|
Very
Low
|
|
Temminck’s Stint
|
Calidris temminckii
|
Low
|
Low
|
|
White-throated Kingfisher
|
Halcyon smyrnensis
|
Low
|
Low
|
|
Wood Sandpiper
|
Tringa glareola
|
Very
Low
|
Very
Low
|
|
Herpetofauna
|
|
Common Rat Snake
|
Ptys mucosus
|
Low
|
Low
|
|
Indo-Chinese Rat Snake
|
Ptys korros
|
Low
|
Low
|
|
Mangrove Water Snake
|
Enhydris bennettii
|
Low
|
Low
|
* Survey data indicate that these
species only occur in the area occasionally and are unlikely to depend on the
site.
13.8.85
During baseline surveys the
presence of an egrety resulted in concerns about the potential for the
construction of the Residential Development to form a barrier to egret flight
lines. To address this potential impact a design decision was made to relocate
the development to minimise intersection with observed flightlines. In addition
the construction of a potential alternative egretry is proposed within the WNR.
Recently the egretry has been abandoned and whilst there is little prospect of
it becoming re-established it has been decided to retain these mitigation
measures.
13.8.86
Fragmentation caused by the
erection of site fencing is not expected to cause a significant impact to
Species of Conservation of Importance recorded within the site, although it
could restrict the movement of species such as Eurasian Otter and Crab-eating
Mongoose which, whilst not recorded within the Assessment Area, might be
expected to be present.
13.8.87
Options 1A and 1B are similar in many respects, the
slight difference between these two options arising from the larger number of
buildings in Option 1B. The gaps between buildings will be smaller in this
option creating a slightly greater blockage of sightlines for birds. It is
predicted, therefore, that Option 1B will result in slightly greater habitat
fragmentation than Option 1A.
It is emphasised that the difference between these options is slight,
particularly in light of the abandonment of the egretry, as it was the
potential blockage of flights to and from this feature that was the principal
source of concern with respect to habitat fragmentation.
13.9.1
In Section 13.8 five main
categories of potential ecological impacts were identified on habitats and
Species of Conservation Importance:
·
Temporary habitat loss
resulting from construction phase disturbance (particularly noise and
vibration).
·
Permanent habitat loss
associated with the construction of the residential development. In addition
disturbance associated with the operation of the site is expected create an
area around the development within which density of sensitive species
(primarily birds) will be permanently reduced.
·
Habitat fragmentation arising
from the construction of the residential development and erection of fencing.
·
Pollution events arising from
construction activities.
·
Pollution events arising from
sewerage leaks during site operation.
13.9.2
Of these the permanent habitat
loss associated the construction and operation of the residential development
is the most significant because it will potentially have a high impact on
habitats of high conservation value (aquaculture ponds) and Species of
Conservation Importance (including the globally important species Black-faced
Spoonbill).
Mitigation of Construction
Phase Habitat Loss and Disturbance
13.9.3
The key strategy for mitigating
permanent and temporary habitat loss arising from the construction of the
Residential Development is the construction and appropriate management of a
Wetland Nature Reserve (WNR) within that component of the site (approximately 76.1 ha) not occupied by the proposed
residential development. The aim of the WNR is to compensate permanent habitat
loss and to mitigate disturbance effects through the creation of approximately 14.4 ha. of freshwater marsh habitat. In
addition approximately 61.7 ha
of remaining fishponds will be enhanced and managed to increase their carrying
capacity for bird Species of Conservation Importance.
13.9.4
The strategy for constructing
the WNR has been carefully considered and incorporates the following
(strategic) elements:
·
Advance construction.
Construction works associated with the WNR will be completed in advance of the
commencement of construction at the Residential Development – this minimises
concurrent disturbance associated with construction works in these two areas.
·
Staged construction. The
construction of the WNR will be staged to minimise the areas affected at any
one time. This minimises disturbance effects and ensures that there is always
sufficient habitat for birds, and other species, considered to be of
Conservation Importance within Fung Lok Wai.
·
Interim management. To ensure
that carrying capacity of areas unaffected by construction at any one time are
sufficient to maintain populations of bird (and other) Species of Conservation
Importance, interim management will be undertaken during WNR and Residential
Development construction phases.
·
Long-term management. Once
construction works are completed and the Residential Development enters its
operational phase, long-term management within the WNR will commence.
13.9.5
The construction programme for
the WNR and Residential Development is indicated in Figure 13‑13. The timeframe for these
works has been divided into series of Phases, including:
·
Pre-construction Phases I-VI –
when WNR works and proposed Development Area site clearance and forming will be
undertaken.
·
Construction Phase – when work
on the Residential Development foundations and superstructure will take place.
·
Operation Phase – when the
Residential Development is occupied and the WNR enters long-term management.
13.9.6
The activities involved in each
stage are briefly described below (dates shown are indicative).
Pre-Construction Phase I
(Jul ‘10– Sep ‘10)
13.9.7
During this phase the developer
will take occupation of the site and make preliminary preparations including
erection of site fencing. No specific habitat management is envisaged at this
stage and all ponds will remain under their current aquaculture regime. All
ponds will potentially be available as habitat that is no ponds will be
directly affected by construction activities.
Pre-Construction Phase II
(Oct ’10 – Mar ’11)
13.9.8
During this phase pond
enhancement works will commence. Enhancement is aimed at improving the quality
of ponds as waterbird habitat (as described more fully in Section 14) and
involves re-profiling and enlarging the ponds. To minimise disturbance and to
maximise the extent of available habitat these works will be undertaken
progressively within Sector 1. The works involved in enhancement include the
draining of adjacent ponds and the excavation of the intervening bund. This
will be done according to the construction plan of the Wetland Nature Reserve
(see Section 14). These works are similar to normal pond management activities
and are not in themselves expected to cause undue disturbance to birds,
nevertheless to minimise potential disturbance impacts, pond enhancement works
will be phased.
13.9.9
The maximum area of pond
affected by these enhancement activities during this Phase will be 4.2 ha (representing the largest ponds that
will be concurrently drained and re-profiled). Prior to, and following
enhancement works, the ponds will be filled with water and are considered to be
available as habitat for birds and other Species of Conservation Importance.
13.9.10
During these works the ponds
located within Sectors 2 and 3, the area proposed for marshland (14.4 ha) and development area (4.0 ha) will remain under their existing
management regime ensuring that, throughout this Phase, at least 76.0 ha of pond will remain as available.
Pre-Construction Phase III
(Apr ’11 – Sep ’11)
13.9.11
During this Phase enhancement
works will commence in Sector 2 and site clearance will commence in the
Development Area. The enhancement works in Sector 2 will follow the same
pattern as described above, however, the maximum area affected at any one time
will be slightly larger at approximately 6.1 ha. Once the Development Area clearance is complete
a further, approximately, 4.0 ha
of pond habitat will become unavailable. During this Phase, therefore, the
minimum pond area available as habitat will be approximately 70.0 ha.
13.9.12
To compensate for this
reduction in habitat area it is proposed to commence interim management in the
Sector 1 ponds (all of which were enhanced in Phase II). The interim management
strategy is to increase the carrying capacity of ponds by drawing them down for
longer periods than is normal under traditional management and to artificially
increase the availability of prey species for wetland birds through stocking of
trash fish species. The key elements of the interim management plan include:
·
Management of water quality,
specifically pH to ensure appropriate conditions for fish survival. Although
trash fish species are relatively hardy compared to many commercial fish, they
can be affected by low pH conditions. If pH drops below 4.5 then peanut residue
will be added to raise pH;
·
Rotational, partial drain down
of pair ponds. Once drained down each pair of ponds will be maintained with
shallow water < 30 cm deep
for a period of 4 weeks;
·
Stocking of trash fish as
required to ensure that target carrying capacities are met; and,
·
Minimising human presence to
limit disturbance.
Pre-Construction Phase IV
(Oct ’11 – Mar ’12)
13.9.13
Interim management will
continue at Sector 1 (20.4 ha)
and commence at Sector 2 ponds (21.3 ha).
In addition interim management will also be implemented in Sector 3 ponds (20.1 ha, although these are yet to be
enhanced). No pond enhancement works will be undertaken during this Phase.
Creation works will commence within the marshland area, while site clearance
continues in the development area, making approximately 14.4 ha and 4.0
ha, of pond area unavailable, respectively. Consequently a
minimum of 61.8 ha of
pond area will be available, all of which will be under interim management.
13.9.14
During this phase the physical
activities associated with marsh creation works will be completed with planting
taking place in the following Phase.
Pre-Construction Phase V
(Apr ’12 – Sep ’12)
13.9.15
Interim management will
continue at Sector 1 (20.4 ha)
and 2 ponds (21.3 ha). Ponds in Sector 3 will undergo enhancement
occupying a maximum of 3.82 ha
at any one time while the remaining 16.2 ha of pond area will be kept under interim
management. Planting of marshland habitats will take place followed by
approximately 12 months of establishment. For the purposes of this assessment
it is assumed during this period that all the marshland habitat (14.4 ha) will be unavailable as habitat
(although it is actually likely that some species will begin to make use of
it). Site clearance and preparation works will continue in the development area
(4.0 ha). Thus a minimum of 58.0 ha of pond area will be available, all
of which will be under interim management.
Pre-Construction Phase VI
(Oct ’12 – Jun ’13)
13.9.16
Marsh establishment will
continue (and hence assumed to be unavailable). Interim management will
continue at Sector 1 (20.4 ha),
2 (21.3 ha) and
3 ponds (20.06 ha) resulting
in a total area of available pond area of 61.8 ha, all of which is under interim management.
Construction Phase (Jul ’13
– Sep ’16)
13.9.17
Construction works are
programmed to commence in July 2013. During this phase
all pond enhancement works will be completed and a total area of 61.8 ha of ponds will be under interim
management in Sectors 1, 2 and 3. Marsh
establishment is expected to be substantially complete (although maturation
will continue over several additional years). Consequently there will be an
additional 14.4 ha of
marshland habitat available.
13.9.18
The commencement of
construction works will result, however, in the generation of substantially
higher levels of noise and vibration and hence disturbance than was experienced
during Pre-Construction Phases. It is assumed, therefore, that sections of
wetland habitat adjacent to the construction area will be functionally
unavailable to species that are sensitive to disturbance. The extent of these
areas was assessed in Section 13.8 and are summarised in Figure 13‑12 and Table
13‑55.
13.9.19
The key strategy for mitigating
these disturbance effects is to maintain interim management in all of the
enhanced Sector 1, 2 and 3 ponds. It is anticipated that interim management
will increase the carrying capacity of these ponds sufficiently to off-set
temporary functional habitat loss associated with the displacement of birds
from areas affected by construction phase disturbance.
13.9.20
The objective, therefore,
during this Phase is to provide habitat of sufficient quality to maintain the
numbers of birds observed during the baseline. To gain an indication of the
existing carrying capacity of the Fung Lok Wai wetlands, the survey data obtained
during the baseline survey were analysed to identify the maximum number of
birds recorded. These data were then converted to densities by dividing the
maximum number of individuals observed within the within the Study Site by the
extent of wetland in the Study Site (approximately 80.1 ha). The Study Site sits within a larger area of
wetland habitat, for comparison this table also shows the maximum and mean
number of individuals of Species of Conservation Importance observed within the
total Assessment Area. These are also shown as densities achieved by dividing
the counts by the extent of wetland within the Assessment Area (approximately 170.6 ha of wetland). These
data are shown in Table 13‑59.
Table
13‑59 Observed maximum, mean
(counts and densities) of wetland bird species using the wetland in the Study
Site and Assessment Area during 2001
|
Species
|
Mean
and maximum counts and densities (individuals per ha of wetland habitat) of
sensitive species using the wetland in the Study Site and
Assessment Area during baseline surveys
|
|
Study site
|
Assessment area
|
|
Max
|
Mean
|
Max
|
Mean
|
|
Count
|
Density
|
Count
|
Density
|
Count
|
Density
|
Count
|
Density
|
|
Black-faced
Spoonbill
|
38
|
0.47
|
2.77
|
0.03
|
39
|
0.23
|
4.53
|
0.03
|
|
Greater
Spotted Eagle
|
0
|
-
|
-
|
-
|
2
|
N/A
|
N/A
|
N/A
|
|
Imperial
Eagle
|
1
|
N/A
|
N/A
|
N/A
|
1
|
N/A
|
N/A
|
N/A
|
|
Red-billed
Starling
|
12
|
0.15
|
1.10
|
0.01
|
182
|
1.07
|
24.67
|
0.15
|
|
Common
Teal
|
3
|
0.04
|
0.20
|
<0.01
|
643
|
3.77
|
35.47
|
0.21
|
|
Eurasian
Wigeon
|
11
|
0.14
|
1.47
|
0.02
|
74
|
0.43
|
7.73
|
0.05
|
|
Osprey
|
0
|
-
|
-
|
-
|
3
|
N/A
|
N/A
|
N/A
|
|
Black
Kite
|
18
|
0.22
|
1.90
|
0.02
|
29
|
0.17
|
10.37
|
0.06
|
|
Chinese
Pond Heron
|
42
|
0.52
|
11.17
|
0.14
|
80
|
0.47
|
13.00
|
0.08
|
|
Great
Cormorant
|
24
|
0.30
|
4.60
|
0.06
|
92
|
0.54
|
13.20
|
0.08
|
|
Great
Egret
|
128
|
1.60
|
20.87
|
0.26
|
132
|
0.77
|
24.50
|
0.14
|
|
Little
Egret
|
480
|
5.99
|
59.53
|
0.74
|
506
|
2.97
|
122.73
|
0.72
|
|
Black-crowned
Night Heron
|
40
|
0.50
|
6.60
|
0.08
|
46
|
0.27
|
9.60
|
0.06
|
|
Cattle
Egret
|
68
|
0.85
|
16.80
|
0.21
|
72
|
0.42
|
29.83
|
0.18
|
|
Grey
Heron
|
67
|
0.84
|
13.27
|
0.17
|
151
|
1.89
|
41.73
|
0.25
|
|
Striated
Heron
|
3
|
0.04
|
0.37
|
<0.01
|
7
|
0.09
|
1.03
|
0.01
|
|
Collared
Crow
|
10
|
0.12
|
1.10
|
0.01
|
18
|
0.11
|
8.50
|
0.05
|
|
Crested
Serpent Eagle
|
0
|
-
|
-
|
-
|
1
|
N/A
|
N/A
|
N/A
|
|
Little
Grebe
|
12
|
0.15
|
4.17
|
0.05
|
42
|
0.25
|
21.27
|
0.13
|
|
Little
Ringed Plover
|
30
|
0.37
|
2.57
|
0.03
|
38
|
0.22
|
8.87
|
0.05
|
|
Pied
Kingfisher
|
2
|
0.02
|
0.17
|
<0.01
|
6
|
0.04
|
1.30
|
0.01
|
|
Temminck’s
Stint
|
9
|
0.11
|
0.37
|
<0.01
|
20
|
0.12
|
3.13
|
0.02
|
|
White-throated
Kingfisher
|
6
|
0.07
|
1.57
|
0.02
|
15
|
0.09
|
3.47
|
0.02
|
|
Wood
Sandpiper
|
3
|
0.04
|
0.30
|
<0.01
|
12
|
0.07
|
2.17
|
0.01
|
N/A - Indicates that whilst
this species was observed during surveys it was seen only in flight over Fung
Lok Wai in very low numbers. It was not appropriate to calculate densities for
these species
13.9.21
To understand the magnitude of
increase of carrying capacity required under the interim management regime the
extent of habitat loss has been estimated by calculating the proportion of
habitat lost through construction and disturbance during the construction phase
(see Table 13‑60). For these calculations it is assumed that the marsh
area is unavailable (hence permanent habitat loss is shown as 18.4 ha, equivalent to the development
area, 4.0 ha, and the
constructed marsh habitat, 14.4 combined). In practice it is actually assumed
that the marsh will be sufficiently mature during this Phase to provide habitat
for some of Species of Conservation Importance. Habitat loss is calculated on
the basis of the reduced density distances shown in Table 13‑56.
Table
13‑60 Extent and proportion of
direct and indirect (due to disturbance) habitat loss during construction for
sensitive wetland bird species.
|
Species
|
Habitat
loss (ha)
|
Extent
of wetland habitat (ha)
|
Proportion
of wetland habitat affected (ha)
|
|
Permanent
|
Due
to disturbance
|
Max
area affected
|
Study
Site
|
Assessment
Area
|
Study
Site
|
Assessment
Area
|
|
Black-faced
Spoonbill
|
18.4
|
23.4
|
41.8
|
80.1
|
170.6
|
52%
|
24%
|
|
Greater
Spotted Eagle
|
18.4
|
33.0
|
51.4
|
80.1
|
170.6
|
64%
|
30%
|
|
Imperial
Eagle
|
18.4
|
33.0
|
51.4
|
80.1
|
170.6
|
64%
|
30%
|
|
Red-billed
Starling
|
18.4
|
6.4
|
24.8
|
80.1
|
170.6
|
31%
|
15%
|
|
Common
Teal
|
18.4
|
12.0
|
30.4
|
80.1
|
170.6
|
38%
|
18%
|
|
Eurasian
Wigeon
|
18.4
|
12.0
|
30.4
|
80.1
|
170.6
|
38%
|
18%
|
|
Osprey
|
18.4
|
33.0
|
51.4
|
80.1
|
170.6
|
64%
|
30%
|
|
Black
Kite
|
18.4
|
2.0
|
20.4
|
80.1
|
170.6
|
25%
|
12%
|
|
Chinese
Pond Heron
|
18.4
|
12.0
|
30.4
|
80.1
|
170.6
|
38%
|
18%
|
|
Great
Cormorant
|
18.4
|
23.4
|
41.8
|
80.1
|
170.6
|
52%
|
24%
|
|
Great
Egret
|
18.4
|
23.4
|
41.8
|
80.1
|
170.6
|
52%
|
24%
|
|
Little
Egret
|
18.4
|
19.9
|
38.3
|
80.1
|
170.6
|
48%
|
22%
|
|
Black-crowned
Night Heron
|
18.4
|
2.0
|
20.4
|
80.1
|
170.6
|
25%
|
12%
|
|
Cattle
Egret
|
18.4
|
2.0
|
20.4
|
80.1
|
170.6
|
25%
|
12%
|
|
Grey
Heron
|
18.4
|
12.0
|
30.4
|
80.1
|
170.6
|
38%
|
18%
|
|
Striated
Heron
|
18.4
|
12.0
|
30.4
|
80.1
|
170.6
|
38%
|
18%
|
|
Collared
Crow
|
18.4
|
2.0
|
20.4
|
80.1
|
170.6
|
25%
|
12%
|
|
Crested
Serpent Eagle
|
18.4
|
33.0
|
51.4
|
80.1
|
170.6
|
64%
|
30%
|
|
Little
Grebe
|
18.4
|
6.4
|
24.8
|
80.1
|
170.6
|
31%
|
15%
|
|
Little
Ringed Plover
|
18.4
|
6.4
|
24.8
|
80.1
|
170.6
|
31%
|
15%
|
|
Pied
Kingfisher
|
18.4
|
2.0
|
20.4
|
80.1
|
170.6
|
25%
|
12%
|
|
Temminck’s
Stint
|
18.4
|
6.4
|
24.8
|
80.1
|
170.6
|
31%
|
15%
|
|
White-throated
Kingfisher
|
18.4
|
2.0
|
20.4
|
80.1
|
170.6
|
25%
|
12%
|
|
Wood
Sandpiper
|
18.4
|
6.4
|
24.8
|
80.1
|
170.6
|
31%
|
15%
|
13.9.22
It can be seen from Table 13‑60 that the extent of habitat loss within the study site
for the wetland species during construction varies between 25% (for disturbance
tolerant species such as Cattle Egret) and 64% for Greater Spotted Eagle,
Imperial Eagle, Osprey and Crested Serpent Eagle. These species were observed
infrequently, over-head and consequently the reliance of these raptors on Fung
Lok Wai is considered low and that the mitigation proposed below for sensitive
waterbirds will adequately safeguard habitat for this species, particularly in
light of the wider availability of suitable habitat for these species in the North-west New Territories.
13.9.23
The most important conclusion
from Table 13‑60, therefore, is that, habitat availability within the
Study Site for the most sensitive waterbirds (Black-faced Spoonbill, Great
Cormorant and Great Egret) will be approximately halved during the construction
phase.
13.9.24
It should be noted that the
figures presented in Table
13‑60 are highly conservative, they are based on
construction activity occurring within the whole of the development area
simultaneously, which is unlikely to occur. Rather, construction is expected to
proceed in stages with disturbance limited to specific areas of the development
area and a significantly smaller area of surrounding wetland. As mentioned
above it is also assumed that the constructed marsh does not contribute to
available habitat, although in practice it is likely to support some Species of
Conservation Importance. It can also be seen from Table 13‑60 that when the availability of wetland habitat in
neighbouring areas (taken as wetland habitat present in the Assessment Area ie
Study Site plus 500m buffer)
is taken into consideration the extent of habitat loss is significantly less
due to the greater availability of habitat within this larger area.
13.9.25
To mitigate the impact of
direct habitat loss and disturbance effects, temporary management will be
required to increase the carrying capacity within remaining habitat. This
management will take place on-site (ie within the Study Site). The mitigation
targets for key bird Species of Conservation Importance are indicated in Table 13‑61 This table shows the increase in the population
required to mitigate habitat loss and temporary disturbance effects during the
construction phase. Using the results of the baseline surveys the densities (ie
birds per hectare of wetland) implied by these mitigation targets are shown.
Species with low target densities (including Greater Spotted Eagle, Imperial
Eagle, Osprey and Crested Serpent Eagle which recorded very infrequently and
have a limited dependence on the site) have not been included in this table. It
should be noted that these targets are intended as a reference point to inform
the implementation and evaluation of mitigation, which will need to be
undertaken using an adaptive management approach.
13.9.26
Targets are shown only for key
species in Table 13‑61. These species have been selected because they are
considered to be the most sensitive and abundant waterbird species and hence
most susceptible to impacts arising from habitat loss and disturbance. It is
expected that habitat management undertaken to achieve the mitigation targets
defined for these species will be more than sufficient to mitigate impacts on
other species that are less sensitive to disturbance and which occur in lower
numbers.
Table
13‑61 Mitigation targets for key
wetland bird species of conservation importance within remaining wetland areas
of the Study Site required to fully compensate for habitat loss and disturbance
impacts during construction
|
Species
|
Mitigation
target (species population increase)
|
Implied
target densities (birds/ha) using existing baseline data1
|
|
Black-faced Spoonbill
|
Double
|
0.07
|
|
Chinese Pond Heron
|
Increase by 61%
|
0.22
|
|
Great Cormorant2
|
Double
|
0.12
|
|
Great Egret
|
Double
|
0.54
|
|
Grey Heron
|
Increase by 61%
|
0.27
|
|
Little Egret
|
Increase by 92%
|
1.41
|
|
Cattle Egret
|
Increase by 33%
|
0.28
|
Notes:
1 The
figures included for reference only. The actual mechanism for identifying specific
population targets
is to be agreed with AFCD prior to the commencement of the construction.
2 If
Great Cormorant numbers exceed mitigation targets it may be necessary to implement
controls on the size of the population. The implementation of such controls
will be determined in the context of the Adaptive Management framework and in
discussion with AFCD
13.9.27
In practice, because the
populations of these species will fluctuate within the North-west New
Territories due to a
range of external factors beyond the developers control, the targets densities
will be calculated using information obtained from control site locations.
These control sites will be established in appropriate locations to be agreed
with AFCD prior to the construction of the proposed development. Appropriate locations would include places that are known to
support similar communities and populations of birds to those found at Fung Lok
Wai. As such, Lut Chau and Nam Sang Wai are the suggested potential control
sites. The actual locations of the control sites would be confirmed prior to
the construction of the proposed development.
13.9.28
The magnitude of the increase in
carrying capacity required is considered to be achievable on a temporary basis
because:
·
Existing densities
(particularly mean densities) are considered to be low for most of the species
listed (see Table 13‑59), which provides considerable scope for increasing
the carrying capacity of ponds within the Study Site through management.
·
Reference to recent monitoring
reports from monitoring associated with KCRC East Rail extensions at Lok Ma Chau (AEC 2003, 2004, 2006a, 2006b) indicate that the densities
implied for key species (Black-faced Spoonbill, Great Cormorant and Great
Egret) are readily achievable (and have been frequently exceeded).
·
Although monitoring at Lok Ma Chau has indicated that
numbers of Little Egret and Chinese Pond Heron have tended to fall short of
their target numbers for that site (AEC 2006a), the actual densities achieved, particularly
for Chinese Pond Heron have often exceeded the specific mitigation target
densities at Fung Lok Wai for both construction and operational phases. With
respect to Little Egret densities achieved have, in the past, been lower than
construction phase mitigation targets at Fung Lok Wai. Within the adaptive
management programme for Lok Ma
Chau, however, various management actions have been
identified to increase numbers and these have had positive results for Little
Egret (AEC 2006a). AEC
(2006b) further indicates that a density of 2.45 birds/ha has been achieved in
Aug-Dec 2005, a considerably higher density than that required to fully compensate
construction phase disturbance effects at Fung Lok Wai. The results of
monitoring at Lok Ma Chau,
and the management required to achieve targets, will continue to be reviewed.
Relevant lessons from Lok Ma Chau
will be incorporated, where appropriate, within the adaptive management
programme for the WNR at Fung Lok Wai.
13.9.29
Under traditional management
the production of non-commercial by-product, including prawns and fish, such as
Tilapia, that are below marketable weight is in the order of 260 kg/ha/year (See Section 12.4, Aspinwall
1997 and Primavera, 2000). To achieve the mitigation targets the availability
of small fish and prawns will need to be increased to provide enhanced feeding
opportunities. Experience from the implementation of a similar approach by KCRC
at Lok Ma Chau
indicates that optimal stocking densities are likely to be in the range 2-5
times the expected ‘normal’ biomass of trash fish, ie up to 1,300 kg/ha/year. Imported fish will comprise
small Tilapia (target weight approximately 50g / individual). A key reason for the relatively large increase in
stocking density is due to the fact increased prey availability benefits a wide
variety of piscivorous birds, including cormorants and ardeids, all of which
can be expected to increase in numbers within the mitigation area.
13.9.30
The experience at Lok Ma Chau (eg AEC 2006a, 2006b) also indicates that a flexible
(adaptive management) approach is required. The effectiveness of mitigation
requires careful attention to water quality, adjustment to stocking densities,
periodic review of the timing and duration of draw-down and continuous
monitoring.
13.9.31
Not of all of the Species of
Conservation Importance recorded within or close to the Study Site are
piscivorous birds. It is expected, however, that the programme of pond
enhancement and interim management proposed during pre-construction and
construction phases will also benefit these species.
13.9.32
Red-billed Starling and
Collared Crow tend to be closely associated with bund habitats and adjacent agricultural
land-uses. Whilst some bunds will be removed during pond enhancement a
substantial proportion will remain intact, sufficient to maintain the low
observed densities of these birds. Staging the enhancement works will ensure
that the area disturbed during enhancement of the fishponds and the
construction of the marsh habitats will be limited.
13.9.33
With respect to raptors, it is
considered that the actions taken to maintain waterbird densities during the
construction phase, including stocking of ponds with fish species, will off-set
potential disturbance effects. The maintenance of waterbird numbers will
benefit those species that forage on these (Greater Spotted Eagle and Imperial
Eagle) and stocking of fish species will benefit Osprey which is piscivorous.
Black Kite is an opportunistic scavenger utilising a wide range of habitats. It
is highly tolerant of human presence and is expected to continue to forage
within the pond enhancement areas
13.9.34
Waterfowl (Common Teal and
Eurasian Wigeon) will forage on vegetation and other food items found at the
margins of ponds. It is expected that these species will continue to utilise
ponds during the construction phase. If any individuals are displaced from the
Study Site due to disturbance it is anticipated that there will be abundant
ponds in adjacent areas (ie within the Buffer Zone to the Study Site) to
accommodate these birds.
13.9.35
Waders (Little Ringed Plover,
Temminck’s Stint and Wood Sandpiper) will forage on invertebrates associated with
pond margins, the creation of additional shallows and lengthening of draw-down
periods is expected to significantly benefit these species.
13.9.36
Few non-avian Species of
Conservation Importance were considered likely to be directly dependent on the
ponds within the Study Site, although some reptile species are expected to
occur including:
13.9.37
Common Rat Snake (Ptyas mucosus) and Indo-Chinese Rat
Snake (Ptyas korros) – are both
likely to be found in varied habitats including agricultural areas, shrub land,
banks of streams, around aquaculture ponds and reservoirs. Mangrove Water Snake
(Enhydris bennettii) is typically
found in muddy coastal habitats, although in the baseline surveys for this
study it was recorded only once but near fish ponds. It is expected that the
staged approach to the enhancement of the ponds and constructed marsh areas
within the WNR will ensure that sufficient habitat remains for these species
throughout the construction phase.
13.9.38
Banded Krait (Bungarus
fasciatus) and Many-banded Krait (B. multicinctus) have little
reliance on fishpond habitats are not expected to be adversely affected by
construction works.
Mitigation of Operational
Phase Habitat Loss and Disturbance
13.9.39
The disturbance generated
during operational phase (ie once the Residential Development is occupied and
all construction works have ceased) is considered to be significantly lower
than during the construction phase.
13.9.40
Table 13‑62 indicates the extent and proportion of direct and
indirect (due to disturbance) habitat loss during operation. Habitat low is
calculated on the basis of the reduced dernsity distances shown in Table 13‑53.
Table 13‑62 Extent and proportion of direct and indirect (due to
disturbance) habitat loss during operation for wetland bird species
|
Species
|
Habitat loss (ha)
|
Extent of wetland habitat (ha)
|
Proportion of wetland habitat affected (ha)
|
|
Permanent
|
Due to disturbance
|
Max area affected
|
Study Site
|
Assessment Area
|
Study Site
|
Assessment Area
|
|
Black-faced
Spoonbill
|
18.4
|
6.4
|
24.8
|
80.1
|
170.6
|
31%
|
15%
|
|
Greater
Spotted Eagle
|
18.4
|
33.0
|
51.4
|
80.1
|
170.6
|
64%
|
30%
|
|
Imperial
Eagle
|
18.4
|
33.0
|
51.4
|
80.1
|
170.6
|
64%
|
30%
|
|
Red-billed
Starling
|
18.4
|
2.0
|
20.4
|
80.1
|
170.6
|
25%
|
12%
|
|
Common
Teal
|
18.4
|
2.0
|
20.4
|
80.1
|
170.6
|
25%
|
12%
|
|
Eurasian
Wigeon
|
18.4
|
2.0
|
20.4
|
80.1
|
170.6
|
25%
|
12%
|
|
Osprey
|
18.4
|
33.0
|
51.4
|
80.1
|
170.6
|
64%
|
30%
|
|
Black
Kite
|
18.4
|
0.8
|
19.1
|
80.1
|
170.6
|
24%
|
11%
|
|
Chinese
Pond Heron
|
18.4
|
0.8
|
19.1
|
80.1
|
170.6
|
24%
|
11%
|
|
Great
Cormorant
|
18.4
|
4.5
|
22.9
|
80.1
|
170.6
|
29%
|
13%
|
|
Great
Egret
|
18.4
|
6.4
|
24.8
|
80.1
|
170.6
|
31%
|
15%
|
|
Little
Egret
|
18.4
|
1.8
|
20.2
|
80.1
|
170.6
|
25%
|
12%
|
|
Black-crowned
Night Heron
|
18.4
|
0.8
|
19.1
|
80.1
|
170.6
|
24%
|
11%
|
|
Cattle
Egret
|
18.4
|
0.8
|
19.1
|
80.1
|
170.6
|
24%
|
11%
|
|
Grey
Heron
|
18.4
|
0.8
|
19.1
|
80.1
|
170.6
|
24%
|
11%
|
|
Striated
Heron*
|
18.4
|
0.8
|
19.1
|
80.1
|
170.6
|
24%
|
11%
|
|
Collared
Crow
|
18.4
|
0.8
|
19.1
|
80.1
|
170.6
|
24%
|
11%
|
|
Crested
Serpent Eagle
|
18.4
|
33.0
|
51.4
|
80.1
|
170.6
|
64%
|
30%
|
|
Little
Grebe
|
18.4
|
1.1
|
19.5
|
80.1
|
170.6
|
24%
|
11%
|
|
Little
Ringed Plover
|
18.4
|
1.1
|
19.5
|
80.1
|
170.6
|
24%
|
11%
|
|
Pied
Kingfisher
|
18.4
|
0.8
|
19.1
|
80.1
|
170.6
|
24%
|
11%
|
|
Temminck’s
Stint
|
18.4
|
1.1
|
19.5
|
80.1
|
170.6
|
24%
|
11%
|
|
White-throated
Kingfisher
|
18.4
|
0.8
|
19.1
|
80.1
|
170.6
|
24%
|
11%
|
|
Wood
Sandpiper
|
18.4
|
1.1
|
19.5
|
80.1
|
170.6
|
24%
|
11%
|
* Habitat loss for Striated
Heron will be over-estimated here because this is a species primarily of
mangroves and inter-tidal habitats (although it was also recorded in small
numbers within the study site)
13.9.41
As for the construction phase
the largest exclusion areas predicted are for four raptor species that are
considered to have a low dependence on the site. It is assumed that the
mitigation proposed for this phase for waterbirds will be more than adequate to
compensate habitat loss for these species.
13.9.42
The most important conclusion
from Table
13‑62, therefore, is that, habitat availability within the
Study Site for the most sensitive waterbirds (Black-faced Spoonbill, Great
Cormorant and Great Egret) will be reduced by approximately 30% during the
operation phase.
13.9.43
It is anticipated that
sympathetic long-term management of the WNR will be more than sufficient to
mitigate permanent habitat loss and ongoing disturbance caused by operation of
the Residential Development. As a precaution it is assumed that the constructed
marsh habitat within the WNR will be unavailable (although in practice it is
expected to be fully established after several years). Consequently mitigation
has been approached on the basis that mitigation targets will be achieved
through enhancement of the carrying capacity of those fishponds unaffected by
disturbance effects. The managed carrying capacities required within these
fishponds are indicated in Table
13‑63. Species with low target densities (including Greater
Spotted Eagle, Imperial Eagle, Osprey and Crested Serpent Eagle which were
recorded very infrequently and have a limited dependence on the site) have not
been included in this table. It is considered that the establishment of the WNR
will provide, in the long-term, enhanced and secure foraging opportunities for
Greater Spotted Eagle, Imperial Eagle and Crested Serpent Eagle and that this
will off-set any impacts arising from habitat loss and disturbance due to the
construction and operation of either Option 1A or 1B. The area of fish ponds within the WNR will
be less than that which currently exists (as approximately 14.4 ha will be converted into freshwater
marsh habitats), although those fishponds retained will be enhanced through
enlargement and more sympathetic management. Nevertheless, it is considered
that there will be a slight reduction in the extent of foraging habitat
available for Osprey, although this loss is not considered to be significant in
light of the low reliance that this species has on the existing habitats within
Fung Lok Wai.
Table
13‑63 Mitigation targets for
wetland bird species of conservation importance within remaining wetland areas
of the Study Site required to fully compensate for habitat loss and disturbance
impacts during operation
|
Species
|
Mitigation
target (species population increase)1
|
Implied
target densities (birds/ha) using existing baseline data2
|
|
Black-faced Spoonbill
|
Increase by 45%
|
0.05
|
|
Chinese Pond Heron
|
Increase by 32%
|
0.18
|
|
Great Cormorant3
|
Increase by 41%
|
0.08
|
|
Great Egret
|
Increase by 45%
|
0.37
|
|
Grey Heron
|
Increase by 32%
|
0.22
|
|
Little Egret
|
Increase by 33%
|
0.98
|
|
Cattle Egret
|
Increase by 32%
|
0.27
|
Notes:
1 For these calculations it is
assumed that mitigation will be achieved only through management to increase the
carrying capacity of those fishponds unaffected by operational disturbance
2 The figures included for reference only.
The actual mechanism for identifying specific
population targets
is to be agreed with AFCD prior to the commencement of construction.
3 If
Great Cormorant numbers exceed mitigation targets it may be necessary to
implement controls on the size of the population. The implementation of such
controls will be determined in the context of the Adaptive Management framework
and in discussion with AFCD
13.9.44
The key strategy for
compensating the functional loss of wetland arising from the ongoing operation
of the residential development is the appropriate management of the WNR.
13.9.45
A detailed draft Habitat Creation and
Management Plan for the proposed Wetland Nature Reserve (WNR) is provided in
Section 14. In summary, though the WNR will comprise two key elements:
·
A large expanse of retained,
but ecologically enhanced, fishponds; and,
·
An area of re-created ‘natural’
marshland.
13.9.46
Fishponds that are actively
managed for commercial aquaculture in the Deep Bay
area are currently full for most of the year and their use by birds is severely
limited due to their relatively steep sides, deep water and their frequent lack
of marginal vegetation. These characteristics also limit their use by other
species and hence fishponds tend to have relatively low biodiversity compared
to many wetland habitats.
13.9.47
The management of fishponds for
commercial aquaculture, however, creates a key by-product in the form of abundant “trash
fish” – small, non-commercial fish and invertebrates. When ponds are drained down during the winter
months for harvesting, large concentrations of birds can be observed foraging
in the shallow water for trash fish. As only a small proportion of fishponds
are drained at any one time, and only for short periods, the spatial
distribution of feeding birds is highly dynamic and variable as birds seek out
ponds as they are drained. ‘Feeding bottlenecks’ may occur if there are
insufficient ponds to support foraging bird populations.
13.9.48
Although much of the Assessment
Area is composed of wetland habitats in the form of aquaculture ponds, poor
water quality and unsympathetic pond design severely limit its value for most
faunal groups. Furthermore, there is inadequate vegetation cover on the site to
support breeding populations of most wetland birds.
13.9.49
The main objectives of
enhancing fishponds are, therefore, to:
·
Increase the value of fishponds
to herons and egrets outside harvesting periods (i.e. draw-down), by increasing
food resources and food availability and by reducing disturbance effects.
Enhancement of the value of fishponds to such birds outside harvest periods
could reduce the potential for ‘feeding bottlenecks’ thereby possibly reducing
the area of fishponds needed to support the population.
·
Increase their overall
biodiversity value and suitability for non-piscivorous bird Species of
Conservation Importance, non-bird Species of Conservation Importance (e.g.
snakes), and other species such as some mammals (e.g. Eurasian Otter),
amphibians and reptiles, whilst maintaining their current important functions
for herons, egrets and other water birds.
13.9.50
The enhanced fishponds will be
located away from the development area to minimise disturbance impacts. They
will also be contiguous with the main area of fishponds in the WCA and Ramsar
site as a whole. Maintaining a contiguous area for compensation, which is
linked, with an existing area of recognised conservation importance is of
significant ecological value.
13.9.51
The natural wetland area will
consist of a marshland complex, including areas of shallow open mesotrophic
water (i.e. of moderate nutrient status), with adjoining reedbeds and other
emergent vegetation, shallow margins, islands, irregular shorelines, and an
area of seasonally inundated grazed marsh and pools. Such fresh water marshes
are a scare habitat in Hong Kong and would
develop rich and abundant aquatic and emergent plant communities. This in turn
may support rich invertebrate, amphibian and reptile communities.
13.9.52
There are three key features of
this proposed layout:
·
The majority of the fishponds
on the site are maintained, including all those within the Mai Po Inner Deep Bay
Ramsar site boundary. This avoids the loss or detrimental modification of any
wetland area within the Ramsar site and maintains the large open contiguous
block of fishpond habitat in the area.
·
The location of the proposed
area for the re-creation of natural wetlands will maximise the potential for
ecological links with the following complementary adjacent habitats:
o
scrub and woodland habitats on
the hillsides to the south of the site;
o
inter-tidal mangrove habitats
along the former Tai
River outfall; and,
o
the wetland creation at Hong
Kong Wetland Park (HKWP).
o
These habitats may provide
sources for the natural spread and establishment of some plants and animals
within the wetland area. In addition they will provide additional shelter, food
or breeding sites for wetland species and ecological ‘corridors’, which may
facilitate dispersal.
·
As the re-created wetland will
contain abundant tall reedbeds, as well as other tall wetland vegetation and
scattered trees, this will serve as a buffer between the residential
development and the fishponds. This will reduce disturbance of birds feeding
within the fishponds.
13.9.53
The specific aquaculture pond
habitat targets for the mitigation area are indicated in Table 13‑64.
Table 13‑64 Mitigation Targets for Enhanced Aquaculture Ponds
|
Mitigation
issue
|
Target
|
|
Enhancement of aquaculture pond
area
|
61.7 ha.
(Including, control structures and alternative egretry)
|
|
Shallow fish pond area (i.e. < 10cm depth)
|
More than 20% (excluding
aquaculture ponds that are dry for maintenance)
|
|
Cover of undesirable invasive
species and exotic species
|
Less than 10% of vegetation cover
|
|
Plant cover on aquaculture pond bunds
and islands
|
Vegetation of height >10cm to comprise less than
5% plant cover on more than 75% of the area of aquaculture pond bunds and
islands
|
|
Area under traditional polyculture
fish pond management systems
|
70-90% of the aquaculture pond
area
(Excluding aquaculture ponds that
are dry for maintenance)
|
|
Area set-aside from fish farming
and under specific conservation management
|
10 - 30% of the aquaculture pond
area
(Excluding aquaculture ponds that
are dry for maintenance)
|
13.9.54
Planting of trees on bunds will
be avoided where such planting would interfere with bird flightlines. In
addition continuous planting that would enclose or overshadow fishpond or
freshwater marsh habitats will also be avoided. To improve foraging opportunities
for some bird species (notably passerines such as Red-billed Starling)
fruit-bearing trees, including, for example, China-berry (Melia azedarach)
will be planted in small clumps.
13.9.55
The specific targets for the
Marsh Habitat mitigation area are indicated in Table 13‑65.
Table 13‑65 Mitigation Targets for Marsh Habitat
|
Mitigation
issue
|
Target
|
|
Creation and maintenance of a total
of marshland habitat in Favourable Condition
|
14.4 ha.
(including essential structures, e.g. water control structures)
Freshwater marsh habitats
are defined as areas where wetland hydrological conditions, or wetland soils
are present or where wetland plants are dominant, with shallow water (average
< 1m) and
wetland plant species cover greater than 30% of the area.
|
|
Cover of wetland plant species
|
More than 90% established
vegetation (excluding open water marsh area)
|
|
Cover of undesirable invasive
species and exotic species
|
Less than 10% of
vegetation cover
|
|
The average depth of water
|
30 – 50 cm (outside drawn down periods for maintenance)
|
|
Area of open water (i.e.
unvegetated water)
|
20-30%.
|
13.9.56
As the Marsh Habitat will be
new habitat there are no existing animal populations associated with marsh
habitats upon which to base mitigation targets. In addition it is anticipated
that the Marsh Habitat will be subject to disturbance arising during the operation
phase due its proximity to the residential development. Nevertheless there are
a range of bird species that would be expected to use the Marsh Habitat.
Management of the marsh habitats will focus on ensuring that that these
“primary” species (see Table 13‑66) are present. In addition there are a range of other
species that are associated with marsh habitats. Whilst it is desirable that
these species are present, they will not form the primary focus of management
effort. In addition it is expected that the marsh habitat will support a range
of amphibian, reptile and invertebrate species.
Table 13‑66 Bird SpeciesExpected to Use
the Marsh Habitat
|
Primary Species
(Presence expected)
|
Secondary Species
(Presence desirable)
|
|
Birds
Little Egret (R)
Chinese Pond Heron (R)
Great Egret (W)
Grey Heron (W)
Eurasian Teal (W)
Black-winged Stilt (W)
Pintail / Swinhoe’s Snipe (P / W)
Common Snipe (W)
Zitting Cisticola (W)
|
Japanese Quail (P / W)
Eurasian Coot (W)
Pheasant-tailed Jacana (P)
Greater Painted Snipe (R)
Black-winged Stilt (B)
Richard’s Pipit (P / W)
Bluethroat (P / W)
Pallas’s Grasshopper Warbler (P)
|
Key: R – resident; W –
winter; P – passage; B - breeding
Residual Disturbance during
Operation of Wetland Nature Reserve
13.9.57
Lockable gates will also be
placed on vehicle access points to the site. A 2
m high wall between the development area and the wetland will
also prevent direct access except via the designated footpaths.
13.9.58
Fish farming activities within
the Wetland Nature Reserve are also a potential source of disturbance within
the fishpond areas. These will therefore be reviewed, as part of the
development of a management plan for the site, and modified where possible to
avoid disturbance impacts.
13.9.59
Human activities along the
margins of the site, such as walking along tracks and roads and aquaculture
activities on adjacent fishponds may also cause significant disturbance. These
would be reduced to acceptable levels by:
·
Provision of a 2 m high wall between the residential
development and wetland area, which itself would be screened from the wetland
by tall trees (c. 10 m high);
·
Screening on the perimeter bunds
(in aquaculture ponds) through tree and shrub establishment;
·
Additional screening in the
wetland itself and on the margins of open water through planting and
establishment of wetland species of tree and shrub, bamboo and reed; and,
·
Incorporation of design
features such as islands, promontories and inlets of emergent vegetation to
provide further security and areas free of disturbance for birds.
13.9.60
Screening of the wetland will,
however, be avoided where possible in order to provide clear flight lines and
views across to existing surrounding fishponds and hence maintain connection
with the wider Deep
Bay area.
13.9.61
The long-term management of the
WNR is expected to provide benefit to other species in addition to birds. The
wider range of habitats that will present within the WNR, particularly with
respect to the constructed marsh area is expected to provide improved habitat
(over baseline conditions) for species such as:
·
Dragonflies.
·
Amphibians, including, for
example: Two-striped Grass Frog (Rana taipehensis).
·
Reptiles, including, for
example: Common Rat Snake (Ptyas mucosus) and Indo-Chinese Rat Snake (Ptyas
korros).
13.9.62
These species were all recorded
in relatively low abundance during the baseline and it is reasonable to expect
that the abundance of populations of species in these groups will increase.
Mitigation for Disturbance
to Egretry
13.9.63
Habitat fragmentation impacts
were anticipated largely in relation to the potential obstruction of heron and
egret flightlines originating from an egretry at Shing Uk Tsuen by the proposed
residential development. Subsequent to the completion of the baseline surveys,
the egretry has been abandoned. In the absence of an egretry it is considered
unlikely that the residential development will obstruct flightlines as it is
located on the periphery of the wetland area. There is no precedent in Hong
Kong for the re-establishment of abandoned egretries, nevertheless several
measures will be implemented that will reduce the likelihood that flightlines
will be obstructed in the event that herons and egrets resume breeding at Shing
Uk Tsuen.
13.9.64
A decision has been made, for
example, to relocate the proposed development area. Following relocation the
development area is, at its closest point, situated approximately 200m from the previous location of the
egretry.
13.9.65
The factors influencing choice
of egretry location are not clearly understood. The literature review of the
impacts of developments on egretries undertaken as part of the impact
assessment process for this site (AEC 2002) indicates some degree of tolerance
to existing built structures. Investigations of other egretries located within Hong Kong e.g. the Tai Po Market, indicate that the
species nesting therein can tolerate disturbance and adapt to modifications to
the existing landscape, although the extent of this tolerance has yet to be
quantified.
13.9.66
Whilst no specific information
is available on the direct impacts of construction close to egretries, a buffer
zone of 200m is
considered to be sufficient because:
·
The area immediately adjacent
to the egretry is already subject to disturbance. Existing, ongoing human
activity close to the egretry, includes housing, roads, tracks, actively
managed fishpond and actively managed agricultural land;
·
Construction works will be
phased. Construction works in the western most 200m of the Proposed Development Area being undertaken
preferentially within periods of egretry inactivity (ie. September to
February).
13.9.67
There are also options for reducing
potential impact on birds associated with the egretry through the management of
habitats within the proposed Wetland Nature Reserve (WNR). It is known, for
example, that is possible to artificially create egretries through the planting
of appropriate tree, shrub and tall grass species. The successful, early
establishment of a potential alternative egretry location within the proposed
WNR would compensate for any potential impact caused by construction and
subsequent interference with flightlines.
13.9.68
The egretry occupied about
2,000 sq. m of woodland (Figure
13‑8) and it is recommended that any potential alternative
egretry be of approximately the same size. The literature review found that the
species most commonly associated with egretries in the New Territories
include Celtis sinensis, Ficus macrocarpa and Bambusa eutuldoides and it is
recommended that planting focus on the establishment of mature specimens of
these three species. It is proposed that
the potential alternative egretry be located in the north eastern section of
the Study Site which will be subject to minimal disturbance from both the
construction and operational stages of the development.
13.9.69
Analysis of GIS data also
indicates that, during the breeding season, Little Egret and Chinese Pond Heron
are selectively foraging in ponds that have been drained. This observation
supports observations made elsewhere (eg Lok Ma Chau and Mai Po) that drawn-down ponds, particularly those
which are supplemented with “trash fish” stocks, are sought out by wetland
species, particularly ardeids.
13.9.70
Within the proposed management
plan for the WNR, therefore, ponds will be deliberately drawn down to provide
foraging habitat and to direct birds away from areas that are subject to
disturbance or obstruction.
Mitigation for
Non-disturbance Impacts
Minimisation of Dust
Deposition
13.9.71
Dust deposition is a potential
adverse impact in all locations. Dust creation should be minimised using
standard procedures, including the damping down through water spraying during
periods of dry weather. Details of mitigation measures to be used for
minimising dust deposition are included in the Air Quality Impact Assessment.
Minimisation of Increased
Sediment Load
13.9.72
The potentially increased
sediment load during construction will be controlled and minimised through
implementation of good site management practices such as the provision of means
for the sediment to settle before discharge of the clear supernatant. During
operation, sediment loads are likely to be minimal and any solids will settle
in oil interceptors and sediment traps that are incorporated within the
drainage system. Effective management and maintenance programmes are expected
to adequately control potential impacts from this source.
Minimisation of Pollution
13.9.73
Good storage practices and
handling of the chemicals used during the construction period will minimise the
opportunity for impact on the terrestrial and aquatic environments. Spillage
impacts can be minimised by storing chemicals in appropriate bunkers. Regular
maintenance of interceptors will maximise their efficiency in trapping
chemicals before release into the environment.
Soil Compaction
13.9.74
Where works is being carried
out, there is potential for compaction of the ground surface. The extent of the
area to be compacted for works during construction should be minimised to
reduce damage to habitats. Unless immediately required as a part of the managed
mitigation area or for landscape impact mitigation purposes, each area should
be re-instated when the works on that area are complete, to re-establish an
environment as similar as possible to the original habitat. This may require
excavation, removal of compacted (and polluted) material, and replacement with
suitable material for re-creation, particularly in the areas of wetland
creation and along bunds (in aquaculture ponds), which are not to be used for
vehicle access in the long term.
Bird Strikes with Glazed
Blocks
13.9.75
Collisions of birds with built structures
are most frequent where buildings or structures are transparent or reflective
(i.e. glass) or otherwise difficult to see (e.g. wires). If such structures are
avoided then collisions are likely to be infrequent and have minor ecological
significance. This issue is taken into consideration in the mitigation of
landscape and visual impacts and through the design of the residential blocks
and the use of non-reflective glass.
Mitigation for non-bird
Species
13.9.76
On the basis of the report
section above, it is clear that the principal aim of the mitigation must be the
provision of suitable habitats for target species, rather than the restoration
of specific habitats of intrinsic value.
The Study Site currently has a low diversity of habitats and non-bird taxa.
However, the mitigation proposed has been designed to provide additional
habitat and management for non-target species.
13.9.77
The value of the Assessment
Area for Odonata is currently limited because of the lack of high quality
habitat in the form of fast running freshwater streams and undisturbed marshy
areas. With appropriate management however, it is likely that the wetland
habitats of the site could sustain a much more diverse odonate fauna and
include further species of conservation concern. For example, the rare
damselfly Mortonagrion hirosei will be encouraged through the creation of
Phragmites reedbed as part of the wetland marsh design.
13.9.78
Several ponds will not be
stocked with carnivorous or omnivorous fish which predate Odonata and mayfly
larvae. The depth of bunds (in aquaculture ponds) will be reprofiled to create
shallow margins that slope gently down to the base of the ponds. This will
encourage the establishment of floating and emergent plants which dragonfly
larvae are dependent upon. Along the aquatic margin of the ponds a matrix of
short and taller emergent vegetation, bare substrate comprising soft mud and
marshy area will be created.
13.9.79
The enhanced ponds will include
shallow gently sloping areas and deeper steeper areas. This will encourage breeding
of amphibians and the lack of predatory fish in some ponds will also benefit
amphibians whose larvae are also predated by fish.
13.9.80
Poor water quality and highly
modified freshwater habitats severely limit the ecological value of the
Assessment Area for native freshwater fish. The sole running water habitat at
Fung Lok Wai comprises lowland waterways with a muddy substrate. The value of
the area for freshwater fish will be significantly enhanced through design of
the freshwater marsh, improvement of water quality, removal of choking aquatic
weeds, planting of native species and reduction in the abundance of exotic
species.
13.9.81
Mangrove Water Snake was
recorded within the area of fishponds that will be enhanced as part of the
proposed mitigation for the site. The bunds where this species was recorded
will remain intact during the enhancement works. In addition, earthworks within this area will
be undertaken during the fourth quarter to ensure that breeding individuals are
not disturbed. Other reptiles will be encourage to use the site through
provision of the freshwater marsh which will provide more
suitable habitat with the Study Site particular for species of conservation
importance only otherwise recorded within the buffer zone of the Assessment
Area.
13.9.82
The fishpond areas provide
foraging habitat for bat species such as Japanese Pipistrelle and potentially
other species including Noctule. Studies have shown that a colony of 100
pipistrelles may need as much as 3km2
of habitat in which to forage (Ades 1990). The proposals for management of the
fishponds and the design of the freshwater marsh will increase the diversity of
habitats on site for bats and could increase the carrying capacity of the site
for small invertebrates, and hence increase the value of the available foraging
habitat for these species.
13.9.83
Two other mammal Species of
Conservation Importance, Eurasian Otter (Lutra
lutra) and Crab-eating Mongoose (Herpestes
urva) were not recorded during the twelve months of survey but are known to
occur within similar habitats in the Deep
Bay area. These species
will benefit from the extra cover provided within the freshwater marsh, a
reduction in on-site disturbance as a result of the reduction in fishpond
operators managing the reserve, and more stringent guidelines on sympathetic
management practices.
Summary of compensation
levels
13.9.84
Overall levels of compensation
predicted from the above proposed compensation measures for Species of
Conservation Importance that were recorded during the required survey period are
summarised in Table 13‑67Table
13‑67
Table
13‑67 The Overall Levels Of
Compensation Predicted From Compensation Measures For Species Of Conservation
Importance That Were Recorded During The Baseline Surveys At Fung Lok Wai
|
Species
|
Sensitivity
to disturbance
|
Compensation achieved
|
|
Birds
|
|
|
|
Globally Threatened Species
|
|
|
|
Black-faced Spoonbill
|
High
|
Feeding habitat fully
compensated and provided over a longer period; additional secure roosting
habitat provided
|
|
Greater Spotted Eagle*
|
Very High
|
Habitat maintained, enhanced and secured in the
long-term
Minor level of habitat
fragmentation arising from reduction in sightlines, however, this impact is
not considered to be significant in light of the low reliance of this species
on this habitat and the availability of suitable habitat elsewhere within Hong Kong
|
|
Imperial Eagle*
|
|
Habitat maintained, enhanced and secured in the
long-term
Minor level of habitat
fragmentation arising from reduction in sightlines, however, this impact is
not considered to be significant in light of the low reliance of this species
on this habitat and the availability of suitable habitat elsewhere within Hong Kong
|
|
Red-billed Starling
|
|
Habitat maintained and secured in the long-term
|
|
Regionally Important
Species
|
|
|
|
Common Teal
|
Moderate-High
|
Key habitat improved foraging opportunities provided
and secured in the long-term
|
|
Eurasian Wigeon
|
Moderate-High
|
Key habitat improved foraging opportunities provided
and secured in the long-term
|
|
Osprey*
|
Very High
|
|
|
Potential Regional
concern
|
|
|
|
Black Kite
|
Low
|
Key habitat improved foraging opportunities provided
and secured in the long-term
|
|
Chinese Pond Heron
|
Moderate
|
Feeding habitat fully
compensated and provided over a longer period; additional loafing habitat provided;
potential roosting and nesting habitat provided
|
|
Great Cormorant
|
High
|
Feeding habitat fully
compensated; additional loafing habitat provided
|
|
Great Egret
|
High
|
Feeding habitat fully compensated
and provided over a longer period; additional loafing habitat provided
|
|
Grey Heron
|
Moderate
|
Feeding habitat fully
compensated and provided over a longer period; additional loafing habitat
provided; potential roosting and nesting habitat provided
|
|
Little Egret
|
Intermediate-High
|
Feeding habitat fully
compensated and provided over a longer period; additional loafing habitat
provided; potential roosting and nesting habitat provided
|
|
Local conservation concern
|
|
|
|
Black-crowned Night Heron
|
Low
|
Feeding habitat
fully compensated; additional loafing habitat provided
|
|
Cattle Egret
|
Low
|
Feeding habitat
fully compensated; additional loafing habitat provided
|
|
Collared Crow
|
Low
|
Key habitat improved foraging opportunities
provided and secured in the long-term
|
|
Crested Serpent Eagle*
|
Very High
|
Habitat maintained, enhanced and secured in
the long-term
|
|
Little Grebe
|
Moderate-High
|
Feeding habitat
fully compensated; additional loafing habitat provided
|
|
Little Ringed Plover
|
Moderate-High
|
Key habitat improved foraging opportunities
provided and secured in the long-term
|
|
Pied Kingfisher
|
Low
|
Key habitat improved foraging opportunities
provided and secured in the long-term
|
|
Striated Heron
|
Moderate
|
Primarily a species of mangroves and
inter-tidal mudflats. Minimal direct on habitat. in addition additional loafing habitat
provided; potential roosting and nesting habitat provided
|
|
Temminck’s Stint
|
Moderate-High
|
Key habitat improved foraging opportunities
provided and secured in the long-term
|
|
White-throated Kingfisher
|
Low
|
Key habitat improved foraging opportunities
provided and secured in the long-term
|
|
Wood Sandpiper
|
Moderate-High
|
Key habitat improved foraging opportunities
provided and secured in the long-term
|
|
Reptiles
|
|
|
|
Banded Krait
|
Low
|
Key habitat unaffected by construction
works and operation
|
|
Common Rat Snake
|
Low
|
Key habitat improved foraging opportunities
provided and secured in the long-term
|
|
Indo-Chinese Rat Snake
|
Low
|
Key habitat improved foraging opportunities
provided and secured in the long-term
|
|
Many-banded Krait
|
Low
|
Key habitat unaffected by construction
works and operation
|
|
Mangrove Water Snake
|
Low
|
Key habitat improved foraging opportunities
provided and secured in the long-term
|
* Survey data indicate that
these species only occur in the area occasionally and are unlikely to depend on
the site.
13.10.1
An estimate of residual impacts
on habitats and species, taking into account the proposed avoidance,
minimisation and compensation measures proposed above are summarised in Table 13‑68. The residual effects of Options 1A and 1B are predicted to be similar except
in relation to habitat fragmentation.
Table 13‑68 Proposed Mitigation Measures and Predicted Residual Impacts
|
Potential Impact
|
Predicted Residual Impact
|
|
Habitat
loss
|
The construction
of the Residential Development will result in the permanent loss of
approximately 4 ha of
aquaculture ponds. Enhancement works of remaining ponds within the WNR will
ensure, however, that there will be no net loss of either water body area or wetland
function. Advance construction of the WNR will ensure that there is
sufficient alternative habitat for birds displaced by construction
activities.
Interim
management of the WNR is expected to fully compensate functional habitat loss
caused by the construction of the Residential Development and the WNR itself.
Long-term
management of the WNR is expected to fully compensate functional habitat loss
caused by the operation of the Residential Development.
No significant
residual impacts from direct loss of other habitats are predicted.
|
|
Habitat
fragmentation
|
No
significant fragmentation of habitats is anticipated through construction or
operation of the proposed development.
Some
obstruction of flightlines between an egretry at Shing Uk Tsuen and the Fung
Lok Wai wetlands was anticipated, although the significance of this impact
was not predicted to be high. Following the abandonment of the egretry,
however, no impact is now predicted.
Option
1B will result in slightly greater habitat fragmentation than Option 1A. The larger number of buildings in
Option 1B is expected to restrict the sightlines of birds to a slightly
higher degree than would be the case in Option 1A in either case the impact is not considered to be
significant for any species..
|
|
Disturbance
of wildlife by noise and visual movement
|
The
construction and operation of the residential development and WNR have the
potential to disturb sensitive bird Species of Conservation Importance. Enhancement works of remaining ponds within
the WNR will ensure, however, that there will be no net loss of either water
body area or wetland function. Advance construction of the WNR will ensure
that there is sufficient alternative habitat for birds displaced by
construction activities.
Phasing of works
will ensure that the area affected by pond enhancement works associated with
the construction of the WNR will be small at any one time.
Interim
management of the WNR is expected to fully mitigate disturbance effects
caused by the construction of the Residential Development and the WNR itself.
Long-term management
of the WNR is expected to fully mitigate disturbance effects caused by the
operation of the Residential Development.
No significant residual
impact from disturbance of other habitats or species other than birds is
predicted.
|
|
Dust
deposition on surrounding habitats
|
Minimal
residual impact is anticipated.
|
|
Increased
sediment load and pollution of watercourses
|
Minimal
residual impact is anticipated.
|
|
Soil
compaction
|
Minimal
residual impact is anticipated.
|
|
Hydrological
disruption
|
No
residual impact is anticipated.
|
13.11.1
The key objective of mitigation
is to maintain the functional capacity of the Fung Lok Wai wetlands during
construction and operation. This will be achieved during the construction phase
through interim management of ponds that are not directly affected by
construction activities. The carrying capacity of these ponds will be
temporarily increased through management activities known to improve habitat
value for these species, primarily this will involve increasing food
availability for key piscivorous waterbird Species of Conservation Importance.
Mitigation targets have been specified in terms of the proportional increase in
the density of Bird Species of Conservation Importance present within the
mitigation area required to maintain overall population levels of these species
within the Fung Lok Wai Study Area. During the operational phase of the
development, disturbance is predicted to be lower and mitigation will be
achieved through the long-term management of the WNR. Mitigation targets have
also been identified for the same species during this phase. The mitigation
targets are summarised in Table
13‑69. Bird species with low target densities have not been
included in this table as the mitigation targets proposed should accommodate
these species when accommodating key species which are sensitive and/or have
high densities. Banded Krait and Many-banded Krait have been excluded from this
table because they have little reliance on fishpond habitats.
Table
13‑69 Mitigation targets for Key Bird
Species and other Species of Conservation Importance
|
Species
|
Mitigation
target (population increase)
|
|
Construction
phase
|
Operation
phase1
|
|
Birds
|
|
Black-faced Spoonbill
|
Double
|
Increase by 45%
|
|
Chinese Pond Heron
|
Increase by 61%
|
Increase by 32%
|
|
Great Cormorant
|
Double
|
Increase by 41%
|
|
Great Egret
|
Double
|
Increase by 45%
|
|
Grey Heron
|
Increase by 61%
|
Increase by 32%
|
|
Little Egret
|
Increase by 92%
|
Increase by 33%
|
|
Cattle Egret
|
Increase by 33%
|
Increase by 32%
|
|
Other species
|
|
Common Rat Snake
|
Present
|
Present
|
|
Indo-Chinese Rat Snake
|
Present
|
Present
|
|
Mangrove Water Snake
|
Present
|
Present
|
Note: 1 For these calculations
it is assumed that mitigation will be achieved only through management to
increase the carrying capacity of those fishponds unaffected by operational
disturbance
13.11.2
In addition monitoring will
seek to establish the presence or absence of the marsh species listed in Table 13‑66 above.
13.11.3
As indicated previously it is
considered that in the period since completion of the baseline surveys that
bird activity at Fung Lok Wai is likely to have declined (due to a reduction in
management activity and the abandonment of the Shing Uk Tsuen egretry). Pre-construction
surveys of bird populations at Fung Lok Wai will be undertaken after obtaining
the planning approval and application of the lease modification / land exchange.
These surveys will involve monthly counts of each pond within the Study Site
for one year prior to the commencement of construction activities. The extent
and timing of these surveys will, however, be agreed with AFCD prior to their
commencement. All bird species observed within each pond will be recorded.
Particular attention will be given to
key bird Species of Conservation Importance that are
specifically identified in the mitigation targets outlined above. Once
these surveys are completed specific mitigation targets will be agreed with
AFCD.
13.11.4
During the construction and
operation phase monitoring of bird populations (along with other species,
habitats and physical parameters) will be undertaken as indicated in the EM
& A Manual (see also Section 14.5 below).
13.11.5
The EM&A Manual will be
updated periodically to reflect ongoing discussions with AFCD and the need to
revise targets in light of fluctuations to bird populations within the wider
area. The selection of control sites, details of the monitoring survey
methodology and arrangements for reporting on the outcomes of monitoring shall
be agreed with AFCD prior to commencement of construction activities.
13.11.6
It is recommended that
monitoring of the appropriate implementation of mitigation measures intended to
reduce potential impacts on wildlife from, noise and vibration, dust and other
forms of pollution is undertaken during construction.
13.12 References
1.
Ades, (1990). Bats of Hong Kong. World Wide Fund for Nature, Hong Kong.
2.
Ades, G., Anon., Cornish, A.,
Walthew, G. & Young, L. (1995).
Focus on fishponds. Porcupine! Newsletter of the Department of Ecology
& Biodiversity, University
of Hong Kong. No.13.
3.
Anon. (1993). Ecological impact
study of proposed development at Pak Hok Chau, Mai Po. Unpublished
report.
4.
Anon. (2005). Summer 2005
Report: Egretry Counts in Hong Kongwith particular reference to the Mai Po Inner Deep Bay
Ramsar Site. Report by Hong Kong Bird Watching Society to the Agriculture,
Fisheries and Conservation Department, Hong Kong Special Administrative Region
Government.
5.
Anon. (2006). Winter 2005-06
Report on Waterbird Monitoring at the Mai
Po Inner
Deep Bay
Ramsar Site. Report by Hong Kong Bird Watching Society to the Agriculture,
Fisheries and Conservation Department, Hong Kong Special Administrative Region
Government.
6.
Asia Ecological Consultants Ltd
(AEC) (2002) Preliminary study on the potential impact of the proposed residential
development at Fung Lok Wai on the egretry at Shing Uk Tsuen, and on the
potential for colony relocation. Unpublished AEC report.
7.
Asia Ecological Consultants Ltd (AEC) (2003). Wetland Compensation Area
Ecological Monitoring and Adaptive Management Advice. Annual Report, November
2003.
8.
Asia Ecological Consultants Ltd (AEC) (2004). Wetland Compensation Area
Ecological Monitoring and Adaptive Management Advice. Annual Report, October
2004.
9.
Asia Ecological Consultants Ltd (AEC) (2006a). Wetland Compensation Area Ecological
Monitoring and Adaptive Management Advice. 2004 – 2005 Annual Report, March
2006.
10.
Asia Ecological Consultants Ltd (AEC) (2006b). Wetland Compensation Area
Ecological Monitoring and Adaptive Management Advice. Supplementary Report for
August – December 2005. March 2006.
11.
Aspinwall (1997). Study on the
Ecological Value of fish Ponds in Deep Bay Area: Executive Summary. Planning
Department, Hong Kong SAR Government.
12.
Aspinwall Clouston &
Wetlands International – Asia Pacific (1997).
Development of a comprehensive conservation strategy and a management plan in
relation to the listing of Mai Po
and Inner Deep Bay
as a Wetland of International Importance under the Ramsar Convention. Agreement No. CE47/95.
13.
Binnie, Black & Vetch HK
Ltd (2000) Sheung Shui to Lok Ma
Chau Spur Line Environmental Impact Assessment. Agreement No. EA990008
14.
Binnie Consultants Limited (1997a). Reconnaissance survey of benthic and
pelagic fishpond fauna at Fung Lok Wai. Unpublished report.
15.
Binnie Consultants Limited
(1997b) Tin Shui Wai Development Engineering Investigations for Development of
Area 3, 30 & 31 of the Development Zone and the Reserve Zone –
Environmental Impact Assessment - Final Assessment Report. Volumes 1 and 2, February 1997. Territory Development Department, Agreement
No. CE 10/95.
16.
Britton, A.R.C. (1993). Feeding
behaviour of the Little Egret at Mai
Po, Hong Kong. Hong Kong
Bird Report 1992: 176-184
17.
Carey, G.J., Chalmers, M.L.,
Diskin, D.A., Kennerley, P.R., Leader, P.J., Leven, M.R., Lewthwaite, R.W.,
Melville, D.S., Turnbull, M. and Young, L. (2001) The Avifauna of Hong
Kong. Hong Kong Bird
Watching Society, Hong Kong.
18.
Carey, G. (unpublished) Ramsar
Site Waterfowl Monitoring Programme, Hong Kong Bird Watching Society.
19.
Cheung, K. W. 1999. Further
Notes on Freshwater Fish of Hong Kong.
Porcupine! 20: 10.
20.
Chong, D. and Dudgeon, D. 1992.
Hong Kong stream fishes: an annotated
checklist with remarks on conservation status. Memoirs of the Hong
Kong Natural History Society 19: 79-112.
21.
Chu, W. H. (1995) Fish Ponds in
the Ecology of the Inner Deep Bay
Wetlands of Hong Kong. Asian Journal of
Environmental Management. Vol 3, No. 1,
pp13-36.
22.
Collar, N. J., Crosby, M. J. and
Strattersfield, A. J. (1994). Birds to Watch 2. The World List of Threatened
Species. BirdLife Conservation Series No. 4. BirdLife International, Cambridge, UK.
23.
Corlett, R.T. et al. (2000) Hong
Kong Vascular Plants: Distribution and Status. Memoirs of the Hong Kong
Natural History Society. pp1-3.
24.
Endangered Species Scientific
Commission (1998). China
Red Data Book of Endangered Animals. Endangered Species Scientific Commission.,
PRC.
25.
Fellowes, J.R., Lau, M., Dudgeon,
D. Reels, G.T., Ades, G.W.J., Carey, G.J., Chan, B.P.L., Kendrick, R.C., Lee,
K.S., Leven, M.R., Wilson, K.D.P., Yu, Y.T. (2002) Wild Animals to Watch: Terrestrial and freshwater fauna of
conservation concern in Hong Kong.
Memoirs of the Hong Kong Natural
History Society.
26.
Groombridge, B. (1993) (ed).
1994 IUCN Red List of Threatened Animals. IUCN, Gland,
Switzerland and Cambridge, UK.
27.
Hill, D., Hockin, D, Price, D.,
Tucker, G., Morris, R., and Treweek, J. (1997). Bird disturbance: improving the
quality and utility of disturbance research. Journal of Applied Ecology 34:
275-288.
28.
Hockin, D., Ounsted, M.,
Gorman, M., Hill, D., Keller, V. and Baker, M. (1992). Examination of the
effects of disturbance on birds with reference to the role of environmental
impact assessments. J. Environ. Mgmt 36: 253-286.
29.
Holling, C. S. (ed) (1978).
Adaptive environmental assessment and management. John Wiley, Chichester.
30.
IUCN (2000) The 2000 IUCN Red
List of Threatened Species http://www.redlist.org/
31.
KCRC & BBVHK (2002) Sheung
Shui to Lok Ma Chau
Spur Line Environmental Impact Assessment Environmental: Impact Assessment Report
32.
Melville, D.S. (1987). Chinese
Pond Herons Ardeola bacchus eating flies. Hong Kong Bird Report 1987: 58-68
33.
Melville, D.S, Young, L. and
Leader, P.J. (1994). The importance of fish ponds around Deep Bay
to widlilfe especially waterbirds, together with a review of potential impacts
of wetland loss and mitigation measures. WWF Hong Kong.
34.
Mutual Luck Investment Limited
(1998) Objection to Draft Lau Fau Shan & Tsim Bei Tsui Outline Zoning Plan
No. S/YL-LFS/1 – Alternative Proposal.
Volume 1 and 2.
35.
Primavera, J.H. (2000).
Integrated Mangrove – Aquaculture Systems in Asia.
Integrated Coastal Zone Management, Autumn edition, pp. 121-130.
36.
Pritchard, D. E. (1996)
Environmental Impact Assessment: Towards Guidelines of Adoption under the
Ramsar Convention. Technical Session A of the 6th meeting of the conference if the
contracting parties, Brisbane, March 1996.
37.
Ramsar Bureau (no date)
Classification system for wetland type. www.ramsar.org
38.
Tam, N.F.Y. & Wong Y.S.
(1997) Ecological study on mangrove stands in Hong Kong.
Report submitted to AFD, Hong Kong SAR.
39.
Townland Consultants Ltd, Wong
Tung & Partners Ltd, Maunsell Consultants Asia Ltd, MVA Asia Ltd, CES Asia
Ltd, Belt Collins & Associates HK ltd, Nelson and Wright (1992). Sunnyville
Estate development at Nam Sang Wai, Engineering Assessment Report, Nam Sang Wai
Development Co, Ltd & Kleener Investment Ltd.
40.
Town Planning Board (1999).
Guidelines for application for developments within Deep Bay Area under section
16 of the Town Planning Ordinance. TPB PG-No. 12B.
41.
Treweek, J. (1999). Ecological
Impact Assessment. Blackwell, London,
UK.
42.
US Army
Corps of Engineers (USACE) (1987) USACE Wetlands delineation manual. Environmental Laboratory, US
Army Engineers. Waterway Experimental Station
Technical Report. Y-87-1.
43. Walters, C. J. (1986). Adaptive management of renewable resources. Macmillan, New
York.
44.
WWF (2000). http://www.wwf.org.hk/eng/maipo/wildlife/habitats.html
45.
Wilson, K.D.P. (1995a). Dragonflies, diversity and fishponds.
Porcupine! Newsletter of the Department of Ecology & Biodiversity, University of Hong Kong. No.12.
46.
Wilson, K.D.P.
(1995b). Hong Kong Dragonflies, Urban Council of Hong Kong,
Hong Kong.
47.
Wilson, K.D.P.
(1997). An annotated checklist of the Hong Kong
dragonflies with recommendations for their conservation. Memoirs of the Hong Kong Natural History Society, 21: 1-68.
48.
Wilson, K.D.P.,
T.W. Tam, B.S.P. Kwan, K.K.Y. Wu, B.S.F. Wong and J.K. Wong. (2004). Field
Guide to the Dragonflies of Hong Kong. 2nd
Eds. AFCD, Friends of Country Park and Cosmos Books Ltd. Hong
Kong.
49.
Wong, F.K.O. (1991) Habitat
utilisation by little egrets breeding at Mai Po. Hong Kong Bird
Report. 1990: 185-190.
50.
Young, L. (1991). Conservation
of wildlife in the Deep
Bay area: with particular
reference to heron species. pp. 813-822. In: Boxall, J. (ed.) Polmet '91;
Pollution in the metropolitan and urban environment. Hong
Kong Institution of Engineers, Hong Kong.
51.
Young, L. (1993). Habitat use
by herons and egrets (Ardeidae) at the Mai Po Marshes Nature
Reserve, Hong Kong. Unpub. Ph.D. thesis, University of Hong Kong.
14.1.1
This draft Habitat Creation and
Management Plan (HCMP) presents the details for the design and management of the
on-site Wetland Nature Reserve (WNR) that was identified as appropriate
mitigation and compensation for the construction of the residential development
as detailed in Section 13. This is a draft document and key details presented
here, including, for example, stocking densities and monitoring requirements
are to be finalised subject to the endorsement of AFCD or other appropriate
authority. If changes are required in light of the changing
environment/baseline, such changes would need to be agreed with AFCD or the
relevant authorities.
14.1.2
The proposed WNR has been
designed to achieve sufficient functional enhancement to compensate for
long-term operational phase disturbance. Section 3.5.6.4
xiv and xv of the Study Brief also specifically states that the Ecological
Impact Assessment should:
A. Identify any
constraints associated with the finalized mitigation measures.
B. Propose a management
package for the proposed on-site WNR with particular attention to:
i. The
habitat management plan and specification of resources requirement for its
implementation.
ii. The
long-term foundation management system with management guidelines.
iii. The
financial arrangements to sustain the management of the wetland.
iv. The
management agents and their responsibility.
v. A
contingency plan for the management of the WNR before the establishment of the
foundation management.
C. Formulate
an ecological monitoring and audit programme for the periods of construction
and subsequent site operation, including the development and operation of the
WNR.
14.1.3
Objectives A, Bi and C are
covered within this management plan. The structure and financial arrangements
of an independent management foundation to be established for the long-term
management of the WNR (Bii – Bv) are outlined within a separate chapter of the
EIA (Section 15).
Description of
development impacts and proposed mitigation
14.1.4
The EIA carried out on the
project found that there are potential ecological impacts on ecologically valuable
habitats that require mitigation measures. These are:
·
Habitat loss
·
Habitat fragmentation
·
Disturbance
·
Pollution
·
Soil compaction
·
Hydrological disruption
14.1.5
The key strategy for mitigating
permanent and temporary habitat loss arising from the construction of the
Residential Development is the construction and appropriate management of a
Wetland Nature Reserve (WNR) within that component of the site (approximately
76.1 hectares) not occupied by the proposed residential development. The
aim of the WNR is to compensate permanent habitat loss and to mitigate
disturbance effects through the creation of approximately 14.4 ha.
of freshwater marsh habitat. In addition approximately 61.7 ha of remaining fishponds will be
enhanced and managed to increase their carrying capacity for bird Species of
Conservation Importance.
14.1.6
The strategy for constructing
the WNR has been carefully considered and incorporates the following
(strategic) elements:
·
Advance construction.
Construction works associated with the WNR will be completed in advance of the
commencement of construction at the Residential Development – this minimises
concurrent disturbance associated with construction works in these two areas.
·
Staged construction. The
construction of the WNR will be staged to minimise the areas affected at any
one time. This minimises disturbance effects and ensures that there is always
sufficient habitat for birds, and other species, considered to be of Conservation
Importance within Fung Lok Wai.
·
Interim management. To ensure
that carrying capacity of areas unaffected by construction at any one time are
sufficient to maintain populations of bird (and other) Species of Conservation
Importance, interim management will be undertaken during WNR and Residential
Development construction phases.
·
Long-term management. Once
construction works are completed and the Residential Development enters its
operational phase, long-term management within the WNR will commence.
14.1.7
Although Option 1A is relatively more superior than Option 1B
in respect of ecological impacts due to less building blocks and wider building
gaps, it is considered that for both options the impacts from disturbance,
habitat loss and fragmentation, hydrological disruption and soil compaction can
be fully mitigated for through the following habitat compensation measures:
·
Structural and functional
enhancement of existing aquaculture ponds (fishponds that are actively managed,
those that are currently unmanaged, and the intervening bunds)
·
Design and creation of a
naturalistic wetland
·
Establishment of disturbance
buffers
·
Design and construction of a
potential alternative egretry
·
Design and implementation of a
management programme for long-term management of the wetland reserve
14.1.8
Standard avoidance and
minimisation measures, as described within the mitigation measures section of
the EcIA, are considered to be adequate to eliminate other residual impacts,
such as pollution, from other potential impact sources.
14.1.9
The project proponent will be
responsible for the creation, enhancement and management of the WNR during the
construction phase and shall provide an undertaking to take sole responsibility
for management until a designated successor such as an independent Foundation
is identified to the satisfaction of EPD or its agents. Subject to the
necessary agreements from relevant government authorities, an independent,
non-profit Foundation will be established to take over the long-term management
of the WNR. The proponent or its designated successor will implement the
Habitat Creation and Management Plan (HCMP) submitted with the EIA report. Experienced
ecologists will be employed as the Reserve Manager for the day-to-day
management of the WNR and experienced fish farmers will be employed for the
operation of the fish ponds under the supervision and guidance of the Reserve
Manager.
Purpose of the Habitat
Creation and Management Plan
14.1.10
This Habitat Creation and
Management Plan (HCMP) aims to provide the detailed specifications for the
habitat and other ecological mitigation measures to be provided within the Fung
Lok Wai WNR. The content of this management plan aims to compliment the
management goals of the Mai
Po Inner Deep Bay Ramsar Site management plan
in accordance with Ramsar Convention obligations. The recommendations and
specifications given in this document and the accompanying appendices will be
incorporated as appropriate into forthcoming contract documentation.
14.1.11
Thus the document includes:
·
a summary of the current
ecological importance and condition of the site, including physico-chemical
conditions that may affect habitat restoration and enhancement measures;
·
definition of the target
species requiring mitigation at the site and target habitats to be restored,
created or enhanced;
·
a summary of specific habitat
requirements and associated management measures required by target species;
·
detailed design drawings and
specifications for the habitats (e.g. vegetation composition and structure and
water regimes) and associated structures (e.g. water courses for water supply
and drainage and water control structures),
·
management prescriptions and
required actions to maintain the long-term ecological value and functions of
the WNR;
·
a detailed monitoring programme
for habitat attributes and target species; and
·
an outline programme for the
implementation of the HCMP.
Description of the site
Site location and boundaries
14.1.12
The proposed WNR is located to
the south of Inner Deep Bay in
the North West New Territories
of the Special Administrative Region of Hong Kong. Figure
14‑1 illustrates the proposed location of the WNR in the
context of the Deep
Bay environs.
14.1.13
To the west the site is bounded
by mangroves along the tidal creeks of the Tai River
outfall, beyond which are grasslands, reedbeds, a plantation and aquaculture
ponds. Further to the west of Fung Lok Wai is Tin Shui Wai New Town. To the
north-west there is an area of tidal lagoons (near Tsim Bei Tsui) created by
the construction of a causeway for the road and border security fence. The site
is surrounded to the north and east by wetland habitats. A continuous band of
one or two fishponds bound the site to the immediate north, beyond which lies a
belt of mangroves and then the tidal mudflats of Inner Deep Bay. Further to the north-east, beyond
the Shan Pui River,
there is a large area of aquaculture ponds (fishponds that are actively
manages, those that are currently unmanaged, and the intervening bunds) and the
Mai Po Nature
Reserve, a complex of mangrove, gei wai, reedbed and aquaculture ponds.
Aquaculture ponds also bound the site to the east, beyond which is the Main
Drainage Channel for Yuen Long, Kam Tin and Ngau Tam Mei drainage from the Shan Pui
River. This currently
consists of a large area of open water. To the south east lies Yuen Long Sewage
Treatment Works to the south of which lies Yuen Long Industrial Estate. The south of site is bounded by undeveloped
low hills. These are predominantly covered in semi-natural scrub and woodland
vegetation with some grassland and orchards.
Topography and watercourses
14.1.14
The site has an open, flat and
low lying aspect. The major variation in site level is due to the excavation of
the aquaculture ponds. The level on top of the bunds varies from approximately
+3.1 m to +3.3 m PD, at the north and east of the site,
to about +4.2 m PD at
the south.
14.1.15
Water for the fishponds come
from direct rainfall. In the normal
course of aquaculture pond management ponds are periodically drawn-down and
water pumped from one pond to another to conserve resources. After heavy summer
rainfall, ponds may fill and drain into adjacent channels. Channels may also
occasionally be used for transferring water, by pump, between fishponds.
14.1.16
No flow data are currently
available for the drainage channels. However, a site inspection on 10th January
1998 revealed that all channels contained shallow water (c. 10 cm) and that there were low flows from
those draining catchments the adjacent catchments to the south. These
observations have been confirmed on subsequent site inspections.
14.1.17
The mangrove lined channel (Tai River
outfall) at the north-western perimeter of the site is intertidal. The perimeter bunds are approximately +3.8
mPD and higher than the predicted mean high water in the channel (+2.4 m PD). Therefore in normal circumstances
the interior of the site remains free of tidal influence. Overtopping of the
perimeter might occur in an extreme combined high tide and storm event.
However, this is likely to be extremely rare given the past extreme sea levels
at nearby Tsim Bei Tsui which peaked at +3.85 mPD with a return period of 100
years for records between 1974 and 1990. The predicted tidal range for 2002 at
Tsim Bei Tsui is 0-3 mPD with an average peak tide of +2.4 mPD.
Soils
14.1.18
The superficial geology of the
site consists of estuarine deposits of marine and fluvial origin, predominantly
silts and clays. No borehole information
is available from Fung Lok Wai itself, but investigations elsewhere indicate
that lenses of sands and gravels of alluvial origin may occur underneath the
surface estuarine deposits (see Townland et
al. 1992).
14.1.19
The soils of Fung Lok Wai are derived
from mangrove soils and ultimately have their origin as marine sediment and
riverine alluvium. Texturally the soils are dominated by silt and clay
fractions, the relative proportions of which produce soils that vary from clay
through silty clay to silty clay loam (USDA texture classes). Sand content is generally low. Very small
amounts of gravel are present. The soils have been considerably reworked during
reclamation and through management for fish-farming. The soils are poorly
drained and frequently highly saline, rendering them of little agricultural
value.
Existing ecological
interest
Habitat evaluation
14.1.20
The ecological values of the
current habitats are evaluated in the Fung Lok Wai EIA. The most valuable
habitat components of the Assessment Area are wetland habitats. In particular
the extensive block of Aquaculture Ponds (fishponds that are actively managed,
those that are currently unmanaged, and the intervening bunds) that form a
large contiguous area embedded within the broader Deep Bay Area that includes Mai Po. Adjacent to
this central aquaculture pond area there is, in the southern part of the
Assessment Area, a mosaic of other wetland habitats including wet agriculture,
freshwater marsh and reedbeds. Whilst these areas are of less intrinsic
ecological value, their close proximity and functional linkage with the main
aquaculture pond area enhances their overall status.
14.1.21
The egretry in the small Fung
Shui Woodland also in the southern part of the Assessment Area is also a
feature of high ecological value due to the scarcity of active egretries in the
New Territories. Recent information indicates that this
egretry has now been abandoned (see Anon 2005).
14.1.22
The key ecological value of the
Assessment Area is, therefore, the habitat it provides for breeding and
foraging birds, in particular wetland birds such as herons and egrets, ducks
and waders. In addition the Assessment Area also supports reptile Species of
Conservation Importance. Traditional aquaculture and agricultural management
practices have, to a large extent, engendered the value of the site for birds.
At the same time, however, these practices also limit the potential value of
these habitats. Aquaculture ponds are for example small and steep sided which
restricts bird access and pond bunds are cleared to maintain access to ponds.
With more sympathetic management the value of the wetland habitats at Fung Lok
Wai could be significantly higher.
14.1.23
The extensive area of
inter-tidal habitat in the northern part of the Assessment Area is also of
moderate to high ecological value due to the high biological diversity of
mangal systems. There is no direct link between these habitats and the proposed
Development Area, however, and the potential for impact is very low.
14.1.24
All other habitats within the
Assessment Area are considered to have low ecological value due, primarily to
previous and current levels of disturbance (Table
14‑1).
Table 14‑1 Ecological
evaluation of habitats within the Fung Lok Wai Assessment Area
|
Habitat
|
Overall
evaluation
|
|
Aquaculture
ponds
|
High
|
|
Fung-shui
forest
With egretry
Without egretry
|
High
Low to
moderate
|
|
Intertidal
forested wetlands
|
Moderate
to high
|
|
Agricultural
land
Seasonally flooded
agricultural land
Dry agricultural land
Inactive agricultural land
|
Moderate
Low to
moderate
Low to
moderate
|
|
Permanent
freshwater marsh and pools
|
Low to
moderate
|
|
Secondary
woodland
|
Low to
moderate
|
|
Permanent
rivers, streams and creeks
|
Low
|
|
Reedbed
|
Low
|
|
Ditches
and drainage channels
|
Low
|
|
Wasteland
Wasteland
Aquaculture ponds (infilled)
Works in progress
|
Low
Low
Low
|
|
Grassland
|
Low
|
|
Grassland-shrubland
mosaic
|
Low
|
|
Orchard
|
Low
|
|
Plantation forest
|
Low
|
|
Landscaped
area
|
Low
|
|
Developed areas
Developed
area
Wastewater
treatment area
Water
storage area
|
Low
Low
Low
|
Species of Conservation Importance
14.1.25
A list of Species of
Conservation Importance that occur within the development site and 500m buffer zone are listed in Table 14‑2 below.
Table 14‑2 Species of Conservation Importance that occur within the Fung
Lok Wai Assessment Area
|
Common name
|
Scientific name
|
Habitat preference in Hong Kong
|
|
Reptiles
|
|
|
|
Banded Krait*
|
Bungarus
fasciatus
|
Low lying areas near marshes, cultivated fields and shrub land
|
|
Common Rat Snake
|
Ptyas mucosus
|
Varied including agricultural
areas, shrub land and around aquaculture ponds (fishponds that are managed,
currently unmanaged, and the intervening bunds) and reservoirs
|
|
Indo-Chinese Rat Snake
|
Ptyas korros
|
Open
habitats, including banks of streams and reservoirs, cultivated fields, aquaculture ponds
and shrub land
|
|
Many-banded Krait*
|
Bungarus multicinctus
|
Varied,
including forest, agricultural areas and the edges of mangroves
|
|
Mangrove Water Snake
|
Enhydris bennettii
|
Muddy
coastal habitats
|
|
|
|
|
|
Global
conservation concern
|
|
|
Black-faced
Spoonbill
|
Platalea minor
|
Mudflat, drained Gei Wai and aquaculture
ponds
|
|
Greater Spotted
Eagle*
|
Aquila clanga
|
Brackish and freshwater marsh areas and
aquaculture ponds
|
|
Imperial Eagle*
|
Aquila heliaca
|
Marshes, aquaculture ponds and adjacent
hillsides in Deep
Bay area. Also recorded in the NW, NE & central New Territories
|
|
Red-billed
Starling
|
Sturnus sericeus
|
Aquaculture ponds, wet agricultural
areas, perimeter of reedbeds; and natural and artificial drainage channels.
|
|
Regional
conservation concern
|
|
|
Common Teal
|
Anas crecca
|
Shallow wetlands including aquaculture
ponds
|
|
Eurasian Wigeon
|
Anas penelope
|
Intertidal areas, marsh and aquaculture
ponds
|
|
Osprey*
|
Pandion
haliaetus
|
Bays, coastal areas, gei wais,
aquaculture ponds, reservoirs
|
|
Potential
regional conservation concern
|
|
|
Black Kite
|
Milvus migrans
|
Sea, coast, intertidal mudflat,
aquaculture ponds, grassy and shrubby hillsides and harbours.
|
|
Chinese Pond Heron
|
Ardeola bacchus
|
Freshwater marsh, aquaculture ponds, wet
agriculture, rivers and drainage channels.
|
|
Great Cormorant
|
Phalacrocorax
carbo
|
Coastal areas, aquaculture ponds
|
|
Great Egret
|
Egretta alba
|
Wetlands, particularly shallow intertidal
bays, aquaculture ponds and marshes.
|
|
Grey Heron
|
Ardea cinerea
|
Abundant winter visito to Deep Bay
associated with freshwater marsh, aquaculture ponds and bunds, wet
agriculture, rivers and drainage channels.
|
|
Little Egret
|
Egretta
garzetta
|
Wetlands including intertidal mudflats, gei
wai, also aquaculture ponds, wet agriculture, marsh and banks of rivers and
streams
|
|
Local
conservation concern
|
|
|
Black-crowned
Night Heron
|
Nycticorax
nycticorax
|
Coastal and subcoastal wetlands,
including aquaculture ponds, marsh, mangrove, intertidal mudflats, riverine
wetlands
|
|
Cattle Egret
|
Bubulcus ibis
|
Freshwater marsh, aquaculture pond, wet
agriculture.
|
|
Collared Crow
|
Corvus
torquatus
|
Primarily in Deep Bay,
including rocky and sandy shores, intertidal mudflats, gei wai, aquaculture
ponds
|
|
Crested Serpent
Eagle*
|
Spilornis
cheela
|
Hillside, woodland, rocky hilltops, undisturbed
small marshes, abandoned wet paddies
|
|
Little Grebe
|
Tachybaptus
ruficollis
|
Gei wai, aquaculture ponds particularly
those with emergent and submerged vegetation
|
|
Little Ringed
Plover
|
Charadrius
dubius
|
Low lying land close to freshwater: wet
agriculture, reclaimed land, freshwater marsh, aquaculture ponds
(particularly when drawn down) & coastal areas adjacent to freshwater
streams
|
|
Pied Kingfisher
|
Ceryle rudis
|
Fresh, brackish and saltwater wetlands
including aquaculture ponds, gei wai, sheltered bays.
|
|
Striated Heron
|
Butorides striatus
|
Mangroves and inter-tidal mudflats
|
|
Temminck's Stint
|
Calidris
temminckii
|
Feeds and roosts in drawn down
aquaculture ponds. Also forages in freshwater marsh.
|
|
White-throated
Kingfisher
|
Halcyon
smyrnensis
|
Golf courses, gardens, aquaculture ponds.
|
|
Wood Sandpiper
|
Tringa glareola
|
Low lying areas of freshwater marsh, wet
agricultural land and aquaculture ponds in the New Territories
particularly Long Valley. During spring passage observed on the intertidal
mudflats.
|
* Survey data indicate that these species only occur in the area
occasionally and are unlikely to depend on the site.
Summary
of predicted ecological impacts
Habitats
14.1.26
Ecologically valuable habitats
(ie of moderate value and above) affected by the potential impacts of the
proposed development identified above are summarised in Table 14‑3. The potential impacts under Options 1A and 1B on habitats are similar, although
the effects of habitat fragmentation are expected to be slightly greater under
Option 1B than 1A.
Table 14‑3 Summary
matrix of potential impacts on habitats
|
Habitat
|
Habitat loss
|
Habitat fragmentation
|
Disturbance
|
Pollution
|
Soil compaction
|
Hydrological disruption
|
|
Intertidal
forested wetlands
|
|
|
X
|
X
|
|
|
|
Permanent
rivers, streams and creeks
|
|
|
|
|
|
|
|
Ditches and
drainage channels
|
X
|
|
|
|
|
X
|
|
Aquaculture
pond (actively managed)
|
X
|
|
X
|
X
|
X
|
|
|
Reedbed
|
|
X
|
X
|
X
|
|
|
|
Permanent
freshwater marsh and pools
|
|
X
|
X
|
X
|
|
|
|
Seasonally
flooded (wet) agricultural land
|
|
X
|
X
|
X
|
|
|
|
Dry
agricultural land
|
|
|
X
|
X
|
|
|
|
Inactive
agricultural land
|
|
|
X
|
X
|
|
|
|
Orchard
|
|
|
|
|
|
|
|
Fung-shui woodland
|
|
(X)*
|
X
|
X
|
|
|
|
Semi-natural secondary woodland
|
|
|
X
|
X
|
|
|
Note: * only if egret present
14.1.27
The habitats affected the most
directly are aquaculture ponds, however, the establishment of the WNR will
compensate for habitat loss and disturbance caused by the proposed development.
The Fung-shui woodland to the south west of the Proposed Development Area was
initially considered to be highly sensitive due to the presence of an egretry.
The potential effect of flightline obstruction was analysed and a decision was
made to relocate the development to minimise flightlines obstruction.
Subsequent surveys have now demonstrated that this egretry has been abandoned
(see for example Anon 2005) significantly reducing the likelihood of flightline
obstruction the potential effects.
Species
14.1.28
The major potential species
impacts associated with the proposed development relate to:
·
Disturbance to birds caused by
the construction and operation of the proposed development, including the WNR;
and,
·
Fragmentation – in particular
the obstruction of flightlines of birds moving to and from the egretry
(although this impact will be of lesser significance if the egretry remains
abandoned).
Constraints on design
14.1.29
The ecological impacts
summarised above and described in the EIA Report may potentially be mitigated
for through the enhancement or re-creation of a number of wetland habitat
types. There may, however be constraints
affecting the restoration and management of wetland habitats at Fung Lok Wai
and consequently the potential for impact mitigation. Potential constraints are
therefore reviewed on the basis of the site description above and summarised in
Table
14‑4 below.
Table 14‑4 Potential physical constraints on the creation of a Wetland
Nature Reserve at Fung Lok Wai.
|
|
Assessment of constraint
|
|
Size and location of the site
|
The site is relatively large (approximately 80.1 ha)
and dominated by aquaculture ponds (fishponds that are managed, currently
unmanaged, and the intervening bunds), which are contiguous with others in
the Mai Po Inner Deep
Bay Ramsar site and wider Deep
Bay area. It is
therefore essential that the habitats within the proposed WNR remain
ecologically linked and compatible with the surrounding habitats.
|
|
Water quantity
|
Although Hong
Kong has a high level of rainfall there is a
long period of dry weather in winter when evaporation and transpiration
exceeds rainfall. Therefore freshwater marsh, reedbeds and shallow ponds are
susceptible to drying out. Fishponds currently rely on direct rainfall, but
the creation of other shallow wetlands may require additional inputs during
the dry season. Water
is available from run-off from the residential site and two adjacent
catchments.
|
|
Topography, water depth and water level
control
|
There is little variation in ground levels over the
site. Although this is principally advantageous for the creation of ponds and
freshwater marsh, it reduces the potential for moving water between water
bodies by gravity alone. Although the land is low lying flooding with
saltwater due to storm surges is likely to be a rare.
|
|
Water quality
|
Data on water quality in the existing courses
entering the site are not available. However, visual inspection of the catchments
indicates that these are dominated by semi-natural vegetated habitats with no
obvious sources of pollution. It is therefore anticipated that water quality
from these catchments will be adequate for most wetland habitats. Run-off
from the residential development will require screening and removal of
litter, oil and similar pollutants and excessive silt loads during high
rainfall events.
|
|
Substrate
|
The clay
soils over the site are impermeable and therefore suitable for the creation
of permanent waterbodies. The soils hold high levels of sulphide which may
cause acidification problems in aerobic conditions. High salinity, aluminium
and iron levels may also limit the establishment and growth of some plant
species.
|
|
Vegetation establishment
|
Many wetland
plants are already present on the site and may provide source populations.
Commercial sources of wetland plants (e.g. reed seedlings) are readily
available. Opportunistic sources may also become available through the
development of other wetlands in Hong Kong.
|
|
Vegetation growth
|
Plant growth is rapid in Hong Kong
due to the warm and wet climate. Vegetation management measures (such as
mowing or grazing) may therefore be necessary to maintain low growing, open and
varied plants communities within freshwater marsh habitats. Soil conditions
(see above) may, however, retard plant establishment and growth. There are a
number of exotic species that cause problems to native wetland vegetation and
considerable management will be required to control them.
|
|
Disturbance
|
There are
numerous sources of disturbance to birds and other sensitive fauna on the
site, including fish-farming operations, scattered dwellings and the proposed
residential development itself. Disturbance reducing measures will be
required to enhance the use of the site by many species of waterbird.
|
Engineering
14.1.31
The pond enlargement process will
result in the creation of longer bunds than currently exist. Bund re-formation
works will need to be undertaken in a controlled manner to ensure that bund
strength is retained.
Hydrology / Drainage
14.1.32
The main constraint on the
design of the wetland mitigation scheme is the highly seasonal rainfall in Hong Kong. Typically there is a period of water deficit
(i.e. rainfall is exceeded by evapotranspiration) from September to March.
Without an additional source of water it is not normally possible, to maintain
permanent shallow wetlands, such as those required in the proposed freshwater
marsh complex mitigation area. Permanent wetlands may be retained by storing
sufficient water to overcome the deficit period, but such wetlands are then
inundated by water which is too deep for many of the wetland target species
over the much of the annual cycle. Average monthly rainfall evaporation and
deficits are indicated in Figure
14‑2.
14.1.33
Potential water sources include
run-off from the residential development roofs and hard standing and stream
flow from small hillside catchments to the south of the site (Catchments A and
B, Figure
14‑3).
14.1.34
The outfall to the Tai River,
which provides drainage for the area, is tidal. An outfall is required,
therefore, that is resistant to tidal erosion and which, by means of a tidal
flap, allows one way flow and prevents saline water intrusion.
Soils
14.1.35
The soils present at the site
consist of poorly drained marine clays. These are sufficiently impermeable to
maintain wetland conditions or aquaculture ponds (fishponds that are managed,
currently unmanaged, and the intervening bunds) over the site as demonstrated
by the current presence of such habitats, which are in the main solely
maintained by direct rainfall inputs.
14.1.36
They are, however, acid
sulphate soils which can lead to highly acidic conditions when these are
disturbed and dried. Nevertheless vegetation such as Phragmites does spontaneously recover on bunds and therefore the
maintenance of basic vegetation cover is unlikely to be constrained. However,
care with soil handling or remedial measures (e.g. application of lime) may be
needed to establish more sensitive and diverse wetland vegetation of high
ecological value within the marsh areas of the site.
Water Quality
14.1.37
The sources of water for the
WNR are direct rainfall and run-off from the proposed Development Area and
existing catchments immediately to the south of the proposed Development Area.
14.1.38
Using run-off from developed
catchments can lead to eutrophication and toxic metal pollution problems.
Studies of the water quality characteristics of urban run-off in the United States
(USEPA, 1983), for example, indicated that average total phosphorous
concentrations in run-off from residential and commercial sites tend to exceed
targets for shallow non-eutrophic wetlands. Guidelines for total phosphorus in
freshwater wetlands tend to be in the region of 10-60 micrograms l-1
(eg ANZECC 2000).
14.1.39
The study of residential and
commercial sites in the United
States also found copper concentrations of
53 micrograms l-1, lead at 238 micrograms l-1 and zinc at
353 micrograms l-1. In comparison recommended maximum levels for the
protection of aquatic life for these metals are 19 micrograms l-1, 9
micrograms l-1 and 241 micrograms l-1 respectively
(Missouri Department of Natural Resources 1996).
14.1.40
In Hong Kong Binnie Consultants
Ltd (1997) also found that total phosphorus in run-off from developed
catchments tends to exceed guidelines for wetlands (average TP >420
micrograms l-1) although heavy metals were below the guidelines proposed by the
Clean Water Commission above. Furthermore, published river water quality data
for Hong Kong (eg EPD 2002) also indicates that levels of heavy metals in
rivers in the Deep
Bay area tend, on
average, to be below these recommended levels.
14.1.41
The existing catchments that
will supply water to the WNR are dominated by dense semi-natural scrub and
woodland vegetation, are only partially developed and, like the proposed
development, contain only housing with no commercial use. There are no apparent
point sources of pollutants, such as pig farms etc. Water from catchment flow
is likely to be of relatively low nutrient content and Biological Oxygen Demand
(BOD). It is also anticipated that suspended solids (mainly silt) in runoff
during heavy rainfall periods is relatively low due to the existing dense vegetation
cover in the catchments. In addition, it is likely that the concentrations of
toxic heavy metals in the run-off will be below levels that could prove
problematic for aquatic ecosystems.
14.1.42
As most run-off will be
associated with heavy rainfall, it is anticipated that any pollutants from the
residential site will be sufficiently diluted to ensure that a suitable water
quality standard is achieved for the wetland. Nevertheless, as an initial
precaution, run-off water from the residential site will be passed through
traps to remove oil and grease and sand and gravel filters to reduce silt loads
and particulate organic matter prior to discharging into the ditch and the
storage pond. A high proportion of heavy metals and phosphates are normally
bound to sediments and organic matter, the removal of silt will therefore
considerably reduce the levels of these pollutants.
14.1.43
Run-off water from the
catchments and development area will be stored for long periods before entering
the wetland area any remaining silt that is present will be able to settle out
of the water. This will further significantly reduce pollutant levels (from the
residential run-off and catchments A and B). Periodic silt removal from the
storage pond will therefore be required.
14.1.44
In summary, although there are
no major obstacles to the creation of a WNR at Fung Lok Wai, possible
constraining factors may be the low level of the site, soil salinity and pH,
disturbance and the need for active and long-term management of the vegetation
and water-bodies.
Management goals and objectives of the
Wetland Nature Reserve
14.2.1
The key goal of the WNR is the
conservation of Species of Conservation Importance, specifically to mitigate
habitat loss and disturbance during the construction and operation of the
Residential Development. It is intended that the WNR will maintain populations
of Species of Conservation Importance at better than baseline levels (as
established through ongoing monitoring). In the long-term it is anticipated
that the WNR will sustainably support a more diverse flora and fauna than that
currently found at Fung Lok Wai.
14.2.2
As described above the key
strategies for achieving this are:
·
Completion of construction
works associated with the WNR in advance of commencement of the noisiest works
associated with the construction of the Residential Development.
·
Staged construction (to
minimise impacts caused by the WNR works themselves).
·
Intensive interim management of
ponds during the construction phase of the Residential Development.
·
Long-term sympathetic
management of ponds during the operation phase of the Residential Development.
14.2.3
The importance of the wetland
habitats at Fung Lok Wai derives primarily from the resources they provide for
Species of Conservation Importance and in particular wetland birds such as
herons and egrets. Some aspects of traditional aquaculture practice on site,
such as periodic draining of ponds, have increased the attractiveness of
aquaculture ponds to birds. On the other hand the small and uniformly steep
sided form of the ponds limits (those that are managed, currently unmanaged,
and the intervening bunds) their potential. With more sympathetic management
the value of aquaculture ponds at Fung Lok Wai could be significantly higher.
14.2.4
A key objective is to
improve the overall attractiveness of the aquaculture ponds at Fung Lok Wai for
species dependent on wetland habitats. This will be achieved through a
reconfiguration of the ponds to create fewer, larger ponds and the creation of
a complex of freshwater marsh habitats. Increasing fishpond size is expected to
benefit wetland birds as there is evidence many species prefer larger, less
enclosed waterbodies to the small ponds which typify most aquaculture
practices. The removal of some bunds is predicted to have low or negligible
impact on flora or fauna as their intrinsic ecological value is low and no
Species of Conservation Importance were found to be reliant on them. The
complex of freshwater marsh habitats proposed will provide a range of
additional habitats for birds and other flora and fauna, including dragonflies.
14.2.5
Apart from the site formation
works of the marsh and residential developments (which will be carried out
concurrently to shorten the disturbance), pond enhancement works and marsh
construction will be completed before construction of the Residential
Development commences. This will ensure that compensation is achieved during
both construction and operation phases of the Residential Development. To
minimise disturbance caused by WNR construction itself, these works will be
staged. The sequence of construction is outlined in Figure 13-13.
14.2.6
Functional enhancement will be
achieved through enhancement of both the ponds and the approach to aquaculture
management. The management approach during the construction phase will be more
intensive as a greater degree of functional enhancement is required to
compensate for the high level of disturbance anticipated during this period.
Disturbance levels during the operation phase are predicted to be lower and
hence the focus of long-term management within the WNR will be focused on
sustainably maintaining populations of Species of Conservation Importance and
increasing overall biodiversity.
Interim management (Construction Phase)
14.2.7
As indicated within Section 13 a total of 4 hectares of wetland will be
lost under the footprint of the Proposed Development Area. In addition to this,
functional habitat loss has been identified through quantification of impacts
of disturbance on Species of Conservation Importance. To achieve full compensation for the most
sensitive wetland species (see Section 13.9) it will be necessary, during
the construction phase to approximately double the carrying capacity of ponds
unaffected by disturbance. If the requirement to compensate for the disturbance
to these most sensitive species is met, full compensation for the impacts of
direct habitat loss and disturbance to less-sensitive Species of Conservation
Importance is likely to be achieved, as long as appropriate habitat is
provided. Mitigation for other impacts on both birds and other Species of
Conservation Importance are addressed later in this section. Wetland management
principles established previously indicate that such enhancement is readily
achievable for waterbirds (BBV 2002, M. Leven pers. comm., AEC 2004, 2006a, 2006b).
14.2.8
It is anticipated that if
wetland functionality is maintained there should be no significant decrease in
species numbers within the Study Site despite impacts of disturbance in some
areas of the site. So the targets for species of conservation importance are to
maintain at least the baseline levels within the Study Site.
Long-term Management
(Operation Phase)
14.2.9
Once construction is completed
the WNR will be placed under a long-term management designed to compensate for
the lower levels of disturbance caused by the operation of the Residential
Development. Based on traditional aquaculture practices the management during
this period is intended to both maintain populations of Species of Conservation
Importance and to increase overall biodiversity.
14.2.10
Under normal conditions bird
population numbers fluctuate readily between seasons and years as a result of a
variety of factors, including temperature, migratory patterns, food
availability and human disturbance. Changes resulting from such factors cannot
easily be accounted for. Hence the
importance of the Fung Lok Wai site for wetland birds should be taken in the
context of the Mai Po Inner Deep Bay Ramsar site as a whole, so that monitoring takes yearly
fluctuations in bird activity within Deep
Bay into account.
14.2.11
Significant changes will be
used to guide appropriate management within an adaptive management framework.
Habitat condition
targets
14.2.12
The EcIA Report identifies the
habitat requirements of each Species of Conservation Importance identified and
concludes that the most appropriate form of wetland mitigation in the Fung Lok
Wai area is the enhancement of aquaculture ponds (fishponds that are managed,
those that are currently unmanaged, and the intervening bunds) over the
majority of the mitigation area combined with the establishment of shallow
freshwater marsh.
14.2.13
Ponds managed for commercial
aquaculture in the Deep
Bay area are full for
most of the time and their use by birds is severely limited due to their
relatively steep sides, deep water and their frequent lack of marginal
vegetation. These characteristics also limit their use by other species and
hence aquaculture ponds tend to have relatively low biodiversity compared to
many wetland habitats.
14.2.14
The management of fish ponds
for commercial aquaculture, however, creates a key by-product in the form of abundant “trash
fish” – small, non-commercial fish and invertebrates including Gambusia affinis (Mosquito Fish), Macrobrachium nipponense (a prawn) and Oreochromis mossambicus (a species of
Tilapia).
14.2.15
When ponds are drained down during
the winter months for harvesting, large concentrations of birds can be observed
foraging in the shallow water for trash fish. As only a small proportion of
fishponds are drained at any one time, and only for short periods, the spatial
distribution of feeding birds is highly dynamic and variable as birds seek out
ponds as they are drained. ‘Feeding bottlenecks’ may occur if there are
insufficient ponds to support foraging bird populations.
14.2.16
The main objectives of
enhancing aquaculture ponds are, therefore, to:
·
Increase the value of
aquaculture ponds to herons and egrets outside harvesting periods (i.e.
draw-down), by increasing food resources and food availability and by reducing
disturbance effects. Enhancement of the value of ponds to such birds outside
harvest periods could reduce the potential for ‘feeding bottlenecks’ thereby
possibly reducing the area of aquaculture ponds needed to support the
population.
·
Increase their overall
biodiversity value and suitability for other non-bird Species of Conservation
Importance, such as some mammals (eg Eurasian Otter), amphibians and reptiles,
whilst maintaining their current important functions for herons, egrets and
other water birds.
14.2.17
Figure 14‑4 indicates the location of the proposed area of
enhanced aquaculture ponds. These will be placed away from the development area
to minimise disturbance impacts. They would also be contiguous with the main
area of ponds in the WCA and Mai
Po Inner Deep Bay Ramsar site as a whole. Maintaining a
contiguous area for compensation, which is linked, with an existing area of
recognised conservation importance is of significant ecological value.
14.2.18
The design of the wetland
habitats of the WNR and the mitigation targets defined below are informed by
best practice in wetland design and are consistent with principles and guidance
established in key publications including, Hawke & José (1996), Benstead et al. (1997, 1999) and McMullon &
Collins (2004). With respect to fishponds these targets are designed to
maximise the area available for birds that feed by wading into shallows by
specifying targets for shallow water (defined as water less than 10cm in depth). To maximise accessibility and
to minimise the “enclosure” of the ponds, targets have been included to
maintain open bund and island habitats through the maintenance of bare ground
and / or short vegetation. An undesirable feature of fishponds, particularly
those that are not actively managed, is their tendency to become infested with
undesirable weed species. Once established such infestations can be costly and
time-consuming to remove. A specific target is included, therefore, to ensure
that any infestations are kept to a minimum and to prompt early action on
control.
14.2.19
The specific aquaculture pond
habitat targets for the mitigation area are indicated in Table 14-5.
Table
14‑5 Mitigation targets for enhanced fishponds
|
Mitigation issue
|
Target
|
|
Enhancement
of aquaculture pond area
|
61.7 ha. (including bunds, control structures and potential alternative
egretry)
|
|
Shallow
fish pond area (i.e. < 10cm
depth)
|
More
than 20% (excluding aquaculture ponds that are dry for maintenance)
|
|
Cover
of undesirable invasive species and exotic species
|
Less
than 10% of vegetation cover (excluding open water marsh area)
|
|
Plant
cover on bunds and islands (in aquaculture ponds)
|
Vegetation
of height >10cm to
comprise less than 5% plant cover on more than 75% of the area of aquaculture
pond bunds and islands
|
|
Area
under traditional polyculture fish pond management systems
|
70-90%
of the fish pond area
(Excluding
bunds and ponds that are dry for maintenance)
|
|
Area
set-aside from fish farming and under specific conservation management
|
10
- 30% of the fish pond area
(Excluding
bunds and ponds that are dry for maintenance)
|
14.2.20
The targets for the marsh
habitat reflect the desire to create a habitat that is dominated by a diverse
mosaic of wetland microhabitats and plant species. Open water is desirable
within certain sections but should be limited to allow the growth and
establishment of communities associated with permanently wet habitats. It is
anticipated that the area of open water will fluctuate seasonally (greater
extent during the wet season) thus promoting the growth of communities
associated seasonally inundated wetlands. As with fishponds there is potential
for establishment of undesirable and exotic weed species and a specific target
is included to prompt early and effect control of any infestations. The
specific targets for the Marsh Habitat mitigation area are indicated in Table 14‑6
.
Table 14‑6 Mitigation targets for
Marsh Habitat
|
Mitigation issue
|
Target
|
|
Creation
and maintenance of a total of freshwater marsh habitat in Favourable
Condition
|
14.4 ha. (including essential structures, e.g. water control structures, and
other habitats e.g. bunds)
Freshwater
marsh habitats are defined as areas where wetland hydrological conditions, or
wetland soils are present or where wetland plants are dominant, with shallow
water (average < 1m)
and wetland plant species cover greater than 30% of the area.
|
|
Cover
of wetland plant species
|
More than 90% established vegetation
|
|
Cover
of undesirable invasive species and exotic species
|
Less
than 10% of vegetation cover
|
|
The
average depth of water
|
30
– 50 cm
(outside drawn down periods for maintenance)
|
|
Area of open water (i.e. unvegetated
water)
|
20-30%.
|
Species
population targets
14.2.21 The mitigation targets for Species of Conservation Importance
associated with fishpond habitats are summarised in
14.2.22 Table 14‑7 (see
Section 13.9 for the
derivation of these) Banded Krait and Many-banded Krait have been excluded from
this table because they have little reliance on fishpond habitats.
Table 14‑7 Mitigation targets for Species of Conservation Importance associated
with fishpond habitats
|
Species
|
Mitigation target (population increase)
|
|
Construction phase
|
Operation phase
|
|
Birds
|
|
Black-faced
Spoonbill
|
Double
|
Increase
by 45%
|
|
Chinese
Pond Heron
|
Increase
by 61%
|
Increase
by 32%
|
|
Great
Cormorant1
|
Double
|
Increase
by 41%
|
|
Great
Egret
|
Double
|
Increase
by 45%
|
|
Grey
Heron
|
Increase
by 61%
|
Increase
by 32%
|
|
Little
Egret
|
Increase
by 92%
|
Increase
by 33%
|
|
Cattle
Egret
|
Increase
by 33%
|
Increase
by 32%
|
|
Other species
|
|
Common
Rat Snake
|
Present
|
Present
|
|
Indo-Chinese
Rat Snake
|
Present
|
Present
|
|
Mangrove
Water Snake
|
Present
|
Present
|
Notes:
1 If
Great Cormorant numbers exceed mitigation targets it may be necessary to
implement controls on the size of the population. The implementation of such
controls will be determined in the context of the Adaptive Management framework
and in discussion with AFCD
14.2.23 As the Marsh Habitat will be new habitat there are no existing
animal populations associated with marsh habitats upon which to base mitigation
targets. In addition it is anticipated that the Marsh Habitat will be subject
to disturbance arising during the operation phase due its proximity to the
residential development. Nevertheless there are a range of bird species that would be expected to use the
Marsh Habitat. Management of the marsh habitats will focus on ensuring that
these “primary” species (see
14.2.24 Table 14‑8) are present. In addition
there are a range of other species that are associated with marsh habitats.
Whilst it is desirable that these species are present, they will not form the
primary focus of management effort. In addition it is expected that the marsh habitat will support a
range of amphibian, reptile and invertebrate species.
Table 14‑8 Species Expected to Use the Marsh Habitat
|
Primary Species
(Presence expected)
|
Secondary Species
(Presence desirable)
|
|
Birds
Little Egret (R)
Chinese Pond Heron (R)
Great Egret (W)
Grey Heron (W)
Eurasian Teal (W)
Black-winged Stilt (W)
Pintail / Swinhoe’s Snipe (P / W)
Common Snipe (W)
Zitting Cisticola (W)
|
Japanese Quail (P / W)
Eurasian Coot (W)
Pheasant-tailed Jacana (P)
Greater Painted Snipe (R)
Black-winged Stilt (B)
Richard’s Pipit (P / W)
Bluethroat (P / W)
Pallas’s Grasshopper Warbler (P)
|
|
Reptiles
Common Rat Snake
Checkered Keelback
|
Chinese Soft-shelled Turtle
Burmese Python
|
|
Amphibians
Asian Common Toad
Günther’s Frog
Paddy Frog
Brown Tree Frog
Marbled Pygmy Frog
|
Chinese Bullfrog
Three-striped Grass Frog
Spotted Narrow-mouthed Frog
|
|
Dragonflies
At least 20 species
|
Species typically associated with marsh or reedbed habitats:
Marsh Dancer (Onchyargia atrocyana)
Scarlet Dwarf (Nannophya pygmea)
Marsh Skimmer (Orthetrum luzonicum)
Sapphire Flutterer (Rhyothemis triangularis)
Four-spot Midget (Mortonagrion hirosei)
|
Key:
R – resident; W – winter; P – passage; B - breeding
Public
access objectives
14.2.25
Under the management zoning of
the Comprehensive Conservation strategy and Management Plan (Aspinwall Clouston
and Wetlands International 1997) the adjacent areas within the Ramsar site have
been designated as Public Access Zones (PAZ).
The broad aim of these is to facilitate public access to the site for
educational and appropriate recreational purposes.
14.2.26
There will be no public
visitation to the site during the construction phase, when the site is under
the interim management regime.
14.2.27
During the operational phase it
is proposed that public access to the WNR will only be allowed on a restricted
basis at a level that will not conflict with the over-riding objectives of
nature conservation. The primary objective of visitation will be education. To
facilite access a small number of marked footpaths and hides for viewing birds
and other wildlife in a variety of habitats will be provided. Interpretive
materials including information boards and leaflets etc. will also be provided.
14.3
Detailed
design and construction methods
Overview of design and
relationship with surrounding habitats
14.3.1
The proposed WNR will comprise
two key elements (Figure
14‑4):
·
a large expanse of retained,
but ecologically enhanced, aquaculture
ponds, including a potential alternative egretry; and,
·
an area of created ‘natural’ freshwater marsh.
14.3.2
There are three key features of
this proposed layout:
14.3.3
First, the majority of the aquaculture
ponds (fishponds that are managed, those currently unmanaged, and the
intervening bunds) on the site are maintained, including all those within the Ramsar
site boundary. This avoids the loss or detrimental modification of any wetland
area within the Mai Po Inner
Deep Bay Ramsar site and maintains the large open contiguous block of
aquaculture pond habitat in the area.
14.3.4
Second, the location of the proposed
area for the creation of natural wetlands will maximise the potential for
ecological links with the following complementary adjacent habitats:
·
Scrub, woodland and
particularly wetland habitats to the south of the site;
·
inter-tidal mangrove habitats along
the former Tai River outfall; and,
·
the wetland creation at Hong
Kong Wetland Park (HKWP).
14.3.5
These habitats may provide
sources for the natural spread and establishment of some plants and animals
within the wetland area. In addition they will provide additional shelter, food
or breeding sites for wetland species and ecological ‘corridors’ which may
facilitate dispersal.
14.3.6
Third, as the created wetland will
contain abundant tall reedbeds, as well as other tall wetland vegetation and
scattered trees, this will serve as a buffer between the residential
development and the fishponds. This will reduce disturbance of birds feeding
within the fish ponds.
14.3.7
Figure 14‑5 indicates the location and layout of habitats within
the proposed WNR. The total area of the various habitats is summarised in Table 14‑9. The total area of wetland within the site will be
approximately 76.1 ha. This
represents a slight net increase in area of water body, from the current
situation, through enlargement of most fishponds and the consequent loss of
dividing bunds.
Table 14‑9 The area of habitats in the proposed WNR
|
Habitat type
|
Area (ha)
|
Percentage of site
|
|
Fish pond area*
|
61.7
|
77.0%
|
|
Marsh complex
|
14.4
|
18.0%
|
|
Total wetland
|
76.1
|
95.0%
|
|
Residential development
site
|
4.0
|
5.0%
|
|
SITE TOTAL
|
80.1
|
|
NOTE: *Including
potential alternative egretry. All
figures are approximate
Aquaculture pond
area
Rationale
14.3.8
As acknowledged in the
Comprehensive Conservation Strategy and Management Plan for the Mai Po Inner Deep Bay Ramsar Site (Aspinwall
Clouston & Wetlands International – Asia Pacific, 1997) and discussed
previously in this proposal, fish ponds are particularly important habitats in
the Deep Bay area for resident and migratory
herons and egrets.
14.3.9
Under typical management,
however, fish ponds do not provide optimal habitat conditions for herons and
egrets and are particularly poor for many other water birds. In particular,
they have relatively steep and uniform banks which limits the abilities of
herons, egrets and waders to reach food sources. The lack of aquatic plants
(due to the presence of plant eating fish and their high nutrient status and
associated turbidity) also reduces their suitability for many aquatic
macro-invertebrates. The lack of aquatic plants and invertebrates in turn
limits their use by duck species.
14.3.10
Reeds and other tall emergent
and bund (in aquaculture pond) vegetation can provide good habitats for insects
and other invertebrates that, in turn, provide food for other animals including
passerine birds. Existing reeds at Fung Lok Wai, however, occur in scattered
patches and relatively narrow strips, probably because bund and emergent
vegetation is frequently cleared by pond operators to maintain access. These
are of limited value as breeding habitat and provide little cover for larger
species.
Objectives
14.3.11
In order to increase their
value for Species of Conservation Importance and to enhance their overall
biodiversity it is proposed that the ecological functions of most of the
aquaculture ponds (fishponds that are managed, those currently unmanaged and
the intervening bunds) will be maintained and the following enhancements made:
·
The size of some ponds will be increased (Figure 14‑6). This will increase their suitability for herons and
egrets, which tend to avoid smaller ponds, particularly where these are
enclosed by vegetation. It will also facilitate reprofiling works.
·
Selected bunds will be reprofiled to provide shallow sloping and irregular
margins to increase feeding opportunities and efficiency for herons, egrets,
waders, rails and crakes etc.
·
Emergent vegetation will be allowed to
develop (and where necessary established by planting) on some pond margins, to
provide increased cover and feeding habitats for insects and other
invertebrates, amphibians, reptiles, birds (e.g. bitterns, smaller herons,
rails, crakes and some passerines) and mammals. Vegetation will be encouraged
to develop in areas that require screening from disturbance (e.g. along
footpaths and near dwellings and roads etc) and where exposure of ponds to
prevailing trade winds may cause significant erosion problems. Bands of
emergent vegetation will also be linked across the site to provide continuous ecological
corridors linking similar and complimentary habitats within and off the site
(see Figure
14‑7 for illustrative layout).
·
Unvegetated muddy shallows that will be
intermittently exposed as muddy islands will be created in some of the
larger ponds, from the part removal of existing bunds, to provide enhanced
feeding and roosting opportunities for herons, egrets and waders. These
shallows will be exposed as muddy islands by slightly reducing water levels, as
and when required (e.g. during heron breeding periods and peak wader
migration).
14.3.12
Three ponds (2, 3 and 11) will
be permanently taken out of fish production. Two of these (3 and 11) will be
drained and then allowed to partially refilled with rain water to provide
shallow ‘natural’ lakes of high value to waterfowl (as occurred at Mai Po Nature
Reserve). The other small pond (2) will
be used to establish a reedbed to provide cover and nesting sites for the birds
in the aquaculture pond area.
Works
14.3.13
As indicated in Figure 14‑6, 31 ponds (approximately 47.0 ha.) will be consolidated to 18 larger pond,
which will continue to be managed as aquaculture ponds and 6 (approximately 10.27 ha.) will be taken out
of production (consolidated into 3 larger ponds) and managed as rain fed ponds
for duck and other water birds.
14.3.14
Where indicated in Figure 14‑6, bund material currently separating ponds will be
lowered and side cast to create shallow sloping margins to islands and / or
shoals. Actual levels to be attained on each modified bund are based on generic
designs indicated in Appendix 14-1. The generic designs to be used for
each modified bund are as follows (according to bund numbers given in Figure 14‑6):
·
Design Type A- 4, 12, 14, 15
·
Design Type B- 7, 11, 16
·
Design Type C- 6
14.3.15
Remaining bunds to be modified
will be used to create unvegetated muddy shallows as indicated in Figure 14‑6. Each area of shallows will rise at a slope 1:20 from
the indicated waterline, based on Initial Operating Levels. The below water
level slope will be as shallow as feasible.
14.3.16
Each pond will drained, dried
and reprofiled on a three-year to five cycle as typically currently carried out
on aquaculture ponds. During this process each pond bund will be reprofiled to
create as shallow a slope as feasible according to the properties of the bund
material.
14.3.17
In addition, following
reprofiling, further works will be undertaken under the direction of the WNR
Reserve Manager to provide variation in the shoreline profile along the typical
waterline. This will be carried out by using a backhoe to create indentations
along the water line (at the Initial operating Level) by small-scale
excavations and pressing down with the back of the excavator bucket on the
bund. Approximately 30% of the margins of each pond should be worked in this
way to create a ‘scalloped edge’ with shallow shelves just below the Initial
Operating Level (10 –30 cm
depth).
14.3.18
To facilitate vehicle access to
all parts of the site, for water level management and other activities, some
works on the remaining bunds will be necessary.
The tops of the bunds may require some vegetation clearance and
strengthening with a geofabric to enable them to be used as access-ways.
Current practice is to use some stone fill to form the running surface and it
is proposed to extend this where necessary.
14.3.19
An earth covered floating
platform seeded with Paspalum distichum
will be placed in each operating aquaculture pond to provide additional
foraging areas for herons and egrets etc and potential breeding sites for some
water birds (such as Little Grebe) as well as shelter for fish and aquatic
invertebrates.
14.3.20
The engineering requirements
for the construction of the ponds will only consist of installation of a series
of adjustable sluices or similar water control devices to interconnect the
ponds (Figure
14‑7). Ponds 2, 3 and 11 will be connected to the central
drainage watercourse with adjustable sluices or similar water control devices
set at low levels to maintain shallow water by allowing excess water to flow
over the sluice and by gravity to the watercourse (Channel Y).
14.3.21
Other sluices will be installed
to facilitate general water management on the site and allow storm water
run-off, where necessary, via Channel Y. A drainage pipe will be installed to
connect Ponds 12 and 18 (and interconnected ponds) to Channel Y.
14.3.22
All fishpond water will be
obtained by direct rainfall and will be retained and re-circulated during
drain-down periods as necessary. In any one year two ponds will be used as
reservoir ponds as a contingency measure to ensure that pond water levels are
kept within tolerance levels. No surface or groundwater water supplies will be
used for aquaculture pond operations. Note: the reservoir ponds referred to
here are not the same as the Storage Pond which will hold water for use in
Freshwater Marsh habitats.
Pond enhancement works
14.3.23
Enhancements will be staged to
reduce disturbance. To facilitate this, the existing aquaculture ponds have
been divided into 3 Sectors (Figure
14‑13). Reprofiling works will be conducted sequentially
and systematically within these sectors to avoid concurrent activity within the
WNR. The sequence of construction works is summarised in Figure 13-13 and the
management strategy for these ponds, including during construction, is outlined
in Section 14.4 below. The purpose of this management strategy is to mitigate
disturbance effects at all stages of the construction programme.
14.3.24
On acquisition of the site, the
ponds in Sector 1 will be enlarged and reprofiled as indicated in Table 14‑10.
Table 14‑10 Pond enhancement schedule.
(Bund numbers are indicated in Figure 14‑6. Estimated duration includes pond drain down and
construction works but excludes filling time.)
|
Bund
removal sequence
|
Estimated
duration
|
|
Sector 1
|
|
|
1
2,3
4
5
6
7
TOTAL
|
2 weeks
3 weeks
2 weeks
2 weeks
2 weeks
2 weeks
13 weeks
|
|
Sector 2
|
|
|
9
10, 29
TOTAL
|
2 weeks
4 – 5 weeks
6 – 7 weeks
|
|
Sector 3
|
|
|
New bund creation
8
12
11, 14
15, 16
TOTAL
|
4 weeks
2 weeks
2 weeks
3 weeks
3 weeks
14 weeks
|
|
TOTAL DURATION
|
34 weeks
|
14.3.25
As indicated above construction
of the marsh area is programmed to coincide with site formation works
associated with the residential development. To avoid excessive disturbance due
to construction activities, pond enhancements in Sector 3 will be delayed until
completion of works on the constructed marsh. Construction of the marsh is
expected to take 9 months (refer to Figure 13-13 for the timing of these
activities).
14.3.26
Once constructed, Ponds 2, 3
and 11 will be managed under a different regime involving partial drainage to a
specified depth (depending on the time of year) and then maintained at
prescribed levels.
Vegetation establishment
14.3.27
There are no areas of
vegetation or individual plant species or specimens which should be conserved
in situ or transplanted. No protection of existing vegetation is, therefore,
necessary in the aquaculture pond (fishponds that are managed, those currently
unmanaged and the intervening bunds) or freshwater marsh area (described
below). Indeed in many instances the deliberate removal of existing vegetation
of limited ecological value will be required.
14.3.28
A list of the species to be
established on the islands and along the aquaculture pond margins and bunds is
provided in Table
14‑11 below.
14.3.29
Areas to be planted with these
species are indicated in Figure
14‑7. On the remaining bunds natural regeneration of
vegetation will be allowed, but with 25% of these kept as largely bare banks to
provide foraging and/or loafing areas. The areas kept bare will be rotated on
an annual basis at the discretion of the WNR Reserve Manager.
Table 14‑11 Wetland species to be established in the aquaculture pond mitigation area
|
Species
|
Approx.
density (no. m-2)
|
% cover
|
Growth
form
|
Approx.
height for planting (cm)
|
|
Phragmites australis
|
4
|
100
|
Monostands
|
>20 cm
|
|
Paspalum distichum
|
Broadcast seed
|
0 – 100*
|
Monostands
|
N.A.
|
Notes: * Paspalum
distichum seed to be broadcast on permanently dry and seasonally wet
areas. Overall percentage of cover along
bunds to be 25 – 75% around each pond.
14.3.30
Trees and shrubs will be
planted on some bunds to provide cover and to screen sensitive areas of the
wetland from disturbance sources, such as the residential development and
vehicle use. However, care will be taken to ensure that planting does not
impede flight lines for birds or fragment the contiguous areas of open
aquaculture pond habitat.
14.3.31
Only species that are native to
the area will be planted on the bunds, including fruit bearing tress such as
China-berry (Melia azadarach) (a species considered to be naturalised in
Hong Kong) which are known to be attractive to Red-billed Starlings and other
passerines.
Potential alternative egretry
14.3.32
To compensate for potential
disturbance to the the previous Shing Uk Tsuen egretry which was located to the
south-west of the proposed Development Area, a potential alternative egretry
will be constructed within the aquaculture pond area (Figure 14‑6). The potential alternative egretry will duplicate in
size the Shing Uk Tsuen egretry (approximately 2,000 m2).
14.3.33
To minimise potential
disturbance, this alternative site has been constructed as far as possible from
the proposed development area but also away from the perimeter of the WNR.
Furthermore a location has been selected where the base of the egretry can be
constructed around existing bunds which possess mature trees.
14.3.34
Upon the base mature or
semi-mature specimens of Bambusa
eutuloides will be planted as a central core around which mature or
semi-mature Celtis sinensis and Ficus macrocarpa will be planted to
provide cover and structure. These trees will be raised off-site.
14.3.35
The egretry will be planted as
early as possible in the construction programme to provide sufficient time for
maturation of vegetation and establishment.
Freshwater Marsh
Complex
Rationale
14.3.36
Although aquaculture ponds are
habitat for species of conservation importance they are less attractive for
other species and tend to have low overall diversity. The enhancement measures
identified above will go some way toward increasing the diversity of wetland
habitats and species within Fung Lok Wai.
14.3.37
Although largely lost from Hong Kong, freshwater marsh habitat potentially provides
a much more diverse environment and can support a wider range of species.
14.3.38
Marsh habitat that is varied
and composed of a mixture of permanent open lakes of various depths, reedbed
and seasonally inundated areas dominated by grass, sedge and other freshwater
marsh species provides breeding habitat for amphibians, reptiles and
invertebrates such as dragonflies. Such habitat is botanically diverse
(compared to aquaculture ponds) and also provides good year round foraging
habitat for herons and egrets as well as, potentially, globally threatened
species such as grey headed lapwing. It can also provide suitable breeding
habitat for a number of locally rare freshwater marsh birds, including, for
example, painted snipe, watercock and chestnut bittern.
14.3.39
Increased aquatic fauna will
also provide more predictable and sustainable food resources for herons and
egrets and other waterbirds throughout the year. Aquatic vegetation is also more
likely to be abundant in such lakes which in turn provides favourable habitat
for winter populations of wildfowl. Seasonal exposure of mud, through small
reductions in water levels would also provide feeding areas for wading birds.
Objectives
14.3.40
A freshwater marsh complex
composed of three distinct regions is proposed (Figure 14‑8):
·
A relatively large area of
permanent marsh comprising a series of interconnected lakes and reedbeds;
·
Seasonal marsh dominated by
tussocky grasses and sedges and temporary pools; and,
·
A storage pond.
14.3.41
The practical design of the
proposed freshwater marsh complex incorporates the following principles:
·
The water supply will be from
direct rainfall supplemented by run-off from the residential development and
catchments A and B (see Figure
14‑3).
·
Treated effluent will not be
discharged into the wetland and there will be no reliance on groundwater.
·
The marsh area will not flood
surrounding land and residential developments.
·
The lakes within the marsh area
will eventually discharge via Channel X or, during storm events, via Channel Y
(see Figure
14‑3) into the Tai
River outfall.
14.3.42
Water control structures will
be installed at the locations indicated in Figure
14‑8 to facilitate water management within the marsh
complex.
Permanent marsh area
14.3.43
The majority of the constructed
marsh area will comprise a series of interlocking shallow (mostly < 0.5m) and deep lakes, the latter acting as
refuges for fish and other species requiring greater depths (see Figure 14‑9). Reeds and other emergent associated vegetation will
be established on the margins of these lakes.
14.3.44
The reedbeds will provide
screening from disturbance for herons and egrets, and fingers of reed will
create further seclusion. The vegetation will also provide an important habitat
for invertebrates, especially dragonflies, potentially including the rare
damselfly Mortonagrion hirosei, which
is confined to reedbeds (Wilson
1995). Reedbeds are also important feeding, nesting and roosting habitats for a
wide range of passerine birds, e.g. migrant warblers.
14.3.45
Water levels will be allowed to
fluctuate with seasonal patterns in rainfall but will be kept within defined
limits to prevent drying out or flooding of susceptible vegetation through
controlled release of water from the storage pond. Water will also be released
judiciously to reduce the rate at which levels drop during the transition between
wet and dry seasons.
14.3.46
Varying ground levels in the
reedbed will provide a variety of water depths; allowing some areas of reed to
dry out during the dry season and others to remain inundated all year round.
14.3.47
A small number of islands would
also be incorporated to maximise shoreline length and provide areas that are
subject to less disturbance for further secure feeding and roosting sites for
herons and egrets.
Seasonal marsh area
14.3.48
A segment of the western part
of the marsh complex will be managed as seasonal wetland receiving water from
direct rainfall, and, during wet months, from the permanent marsh area. When
water exceeds a pre-determined depth within the permanent marsh area water will
flow into the seasonal marsh area via a sluice placed between the two areas.
14.3.49
The seasonal freshwater marsh
area will include a number of temporary pools and a greater range of plant
species than the reed fringes of the permanent marsh area. These habitats hold
different communities of plants and animals to permanent wetland bodies and so
its inclusion as a distinct habitat will further enhance biodiversity within
the proposed WNR.
14.3.50
Temporary pools are not able to
sustain populations of fish and other predators and are therefore particularly
valuable for certain aquatic invertebrates and as breeding sites for various
amphibia, such as, potentially, the narrow-mouthed frog. As water levels naturally drop in temporary
ponds then muddy shorelines are exposed. These provide particularly good
feeding areas for a range of waterbirds, including herons and egrets, as well
as various crakes, rails and waders.
There is a potential to provide additional habitat for species not
previously recorded at Fung Lok Wai. For example, the presence of seasonally
wet grazed areas interspersed with deeper pools may attract Greater Painted
Snipe. Similarly the presence of seasonal marsh adjacent to the deeper pools
with emergent and floating vegetation of the permanent marsh area, including
lotus Nelumbo nucifera, may also
attract Pheasant-tailed Jacana.
14.3.51
Excess water with the seasonal
marsh area will gather at the northern end and exit via channel Y into the Tai River
outflow.
Storage pond
14.3.52
To maximise capacity, the
storage pond will not have shallow margins or contain islands, but will have
reed fringes to provide shelter and disturbance free-zones. Its proposed area
will be approximately 3 ha
with an average depth of approximately 3
m (maximum water level 3.7 m PD, bund level 4.0
m PD) and thus will have a storage capacity of approximately 90,000 m3.
14.3.53
Run-off from the residential
site and catchments A and B will be transported to the storage pond via a pipe
or channel system integrated into the residential development area.
Security of water supply
14.3.54
The long-term sustainability of
the proposed natural wetland system is dependent on adequate year-round water
supplies.
14.3.55
Although the north-west New Territories
receives a high average annual rainfall, during the dry winter period evaporation
exceeds rainfall and wetland areas start to loose water. There is a risk,
therefore, that water levels may drop and shallow wetlands may dry out. It is
essential, therefore, to establish that there will be sufficient water
available to maintain the desired water depths for the wetland habitats during
the winter. A monthly water quantity budget has been developed and from this
feasible water levels predicted. This is provided in detail in Appendix 14-2.
14.3.56
From this water budget it is
predicted that the capacity of the storage pond will be sufficient to maintain
water levels within the target levels. Currently, the water budget predicts
that the water level in the storage pond will not drop below approximately 29
megalitres in the dry season, leaving a reserve of approximately 33% capacity
even during the driest scenario tested Figure
14‑10. This is considered to be sufficient to cope with the
typical variation in rainfall levels observed in Hong Kong,
especially as there is predicted to be a substantial surplus of water available
to fill the storage pond in summer.
14.3.57
The maximum water demand to
meet target levels would peak at about 250,000 litres per day during November.
14.3.58
A number of structures are proposed
to enable manipulations of the water levels across the site (see Figure 14‑8). The storage pond will be connected to the lakes
within the natural wetland area by adjustable sluices. This will allow transfer
of water to the lakes either by flow over the sluice, or, when water levels in
the storage pond fall below those of the lakes, by means of a pump. A sluice on
the storage pond connected via drain Y will allow rapid discharge of surplus
run-off water from the catchments and residential area (e.g. during storms)
without affecting the other ponds.
14.3.59
The lakes will also allow
discharge of water via an adjustable sluice into drainage channel X if
required. The western end of the lakes will also have an adjustable sluice to
provide water to the freshwater marsh area which will then exit via channel Y
into the Tai River outflow.
14.3.60
Water can be re-circulated
through the site, if water stagnation becomes a problem, via a pipe linking the
south-west corner of the site and the storage pond (see Figure 14‑8).
Details of Marsh
Habitat creation works
14.3.61
The successful establishment of
freshwater marsh habitat will require a carefully structured approach to the key
wetland construction stages outlined below.
Major earthworks
14.3.62
Major earth works will be
required to achieve the broad profile of the freshwater marsh hydrological
unit. These works can only be conducted during the dry season when the
substrate is sufficiently firm for heavy equipment to enter onto the site. Once the underlying profile of the
hydrological unit has been achieved waterproof clay linings/curtains may be
required at appropriate locations to prevent water leakage (it is possible that
the clay based bund material (from aquaculture ponds) upon which the marsh will
be created may be sufficiently impermeable that clay lining is not required,
however, this will need to be confirmed at the time of construction).
Water control structures
14.3.63
Water control structures should
be installed before the top soiling and fine profiling is conducted.
Top soiling and fine profiling
14.3.64
Top soiling and fine profiling
of the soil can only be conducted during the dry season when the soil is
sufficiently dry for the fine contouring to be implemented. The topsoil should
only be applied if there is sufficient time to implement planting thereafter,
otherwise it may be washed away by heavy monsoonal rain.
14.3.65
A typical composition for
topsoil would be 55% aquaculture pond bund material, 30% CDG, and 15% river
sand, although the exact specification should be considered further at the
detailed design stage and light of the specific qualities of the material
sourced. Experience in other wetland contexts indicates that pond material
needs to be augmented with Calcium Oxide at a rate of 0.68kg/m3 to
neutralise pH. However, the precise rate of augmentation will need to be
determined at the time of construction.
14.3.66
A typical sequence for top
soiling and profiling could be as follows:
·
Establish basic land formation,
with (if required) clay or water proof curtains in place (and tested).
·
Carry out detailed levelling
survey, with marker posts placed throughout the hydrological unit showing:
o
operational water levels and invert
level of outlet control structures; and,
o
100mm increments from top
water level to invert level of outlet control structure.
·
The profiling is entirely
dependent on the range of water level control offered by the outlet control structure(s)
and all levelling must be carried out in relation to this. Hence the need to
have all control structures in place before earthworks can commence. There may
also need to be some calculations made in relation to hydraulic heads (the rise
in water level generated by restricting flows over a weir).
·
Carry out rough ground marking
showing significant areas of any shallow (emergent) underwater spoil benches
roughly in line with the design drawings.
·
Fill areas with specified soil
mix.
·
As appropriate to the desired
land form, carry out fine level soil manipulation with an aim of creating a
random surface profile with local ridges and furrows on level shallow benches
and carry out local profile detailing (small pools and hummocks) on the
marginal slopes but with a general overall fall as specified.
·
The top 300mm of soil needs to be placed very
carefully and compaction minimised. A settlement factor of at least 15% must be
allowed for.
·
All levels to be checked prior
to machinery leaving each working area to avoid the need for further movement
of machinery.
Flooding and checking integrity of the
hydrological unit
14.3.67
Prior to planting, each
hydrological unit should be flooded with water and left for at least one
week. The water level should be checked
and monitored regularly using a gauge board to determine whether the levels
drop more rapidly between rainfall events than would be expected from
evaporation alone. This would indicate whether waterproofing is incomplete or
faulty. The water level can be expected
to drop slightly initially since the clay will absorb water.
14.3.68
To avoid time consuming and
costly abortive works, the hydrological unit should be checked before soiling
works are undertaken. If the hydrological unit is not intact, then the clay
curtain should be removed, re-laid and the flooding exercise implemented again
to confirm whether the unit is water tight.
Planting
14.3.69
To facilitate successful
establishment of the plants in the newly constructed marshes, planting should
commence in April and May prior to the onset of the monsoon rains to coincide
with the plant growing season.
Sufficient resources should be provided for in the programme to ensure
that planting can be completed within one growing season. Planting will include
the following stages:
·
Ensure that the marsh is an
intact hydrological unit ie. any clay curtains and control structures are
sealed, intact and functional.
·
Ensure that all earthworks are
complete and levels checked.
·
Set outlet control structures
to an appropriate level (eg c. 100mm)
below operational (final) water levels to expose most of the bed of the shallow
wetland margins where emergent plants are to be placed. Each plant to be
introduced should have a depth/hydrology assessment made of it (ie. the
maximum, minimum and optimal depth tolerances and the ability/requirement of
the plant to withstand seasonal variation in water levels). It is assumed that
planting plans have been formulated on the basis that species capable of the
deeper tolerance ranges are located in the deeper parts of the marsh and
surface wet or seasonally inundated species are at the higher levels.
·
The general planting procedure
would then be to plant species according to the layout in the planting plans
(e.g. in mono-specific blocks (circles) of 5m diameter, or smaller depending on available
suitable water depth/profile, with gaps of c 1-2 metre between to allow natural
expansion of the species blocks or some natural colonisation). Colour coded
markers would be placed prior to planting with each colour representing a
species and each marker the centre of the planting block. Plants would then be
planted according to the specified planting density, which should depend on the
size/growth form of species and planted material. In this way the site botanist
and ecologists can plan the very specific layout prior to planting.
·
In handling the plant material,
the following is essential:
o
Plants, particularly rhizomes,
need to be kept moist and out of direct sunlight at all times;
o
In planting rhizomatous
species, damage to the rhizome can be made during firming in with tools or
boots. If the substrate is soft enough plants can be pushed gently into the wet
ground. Otherwise the rhizomes will be planted in dug holes and soil replaced
with only gentle firming. Plug plants can be simply placed into a whole made by
a suitable-sized dibber. Submerged plants must be planted underwater and are
normally just pushed into the bottom sediments. In some case it may be
necessary to weigh down the plant with an attached stone/weight prior to the
plant developing established roots;
o
Many aquatic plants will not
survive if dug from wet nursery soils and left standing in water at the
planting site, prior to re-planting. Wherever possible, plants should be
lifted, transported and re-planted within 24 hours. Where this is not possible,
plants should be dug into holding areas of wet soil, not just stacked in
shallow water alone. The soil will need to be kept wet or covered in some way
to reduce water loss;
o
Soils/pots must be checked for
non-target species and unhealthy, or otherwise substandard plants, and these
must be appropriately discarded prior to transplanting.
Management of water levels
14.3.70
Following planting, water
levels should be maintained at initial target levels. The water level should be gradually raised to
the operational level as the plants grow, this approach will also effectively
control the establishment and spread of weeds.
Throughout this time water levels should be carefully controlled to
protect plants from drying out (i.e. a source of water to counter
evapotranspiration) or from being flooding (i.e. sporadic heavy rainfall).
Vegetation
14.3.71
A list of the species to be
established in the freshwater marsh mitigation areas is provided in
14.3.72
Table 14‑12. The
planting list is derived from those native species known from remaining fresh
water marshes in Hong Kong (e.g. Luk Keng
Marsh, Liu Pok Marsh). However, all such wetlands are highly modified by man
and/or domestic animals and therefore ‘true natural’ wetland plant communities
in Hong Kong cannot be easily identified. A variety of
potential mix options are shown for seasonally inundated habitats and a more
detailed planting plan will be produced indicating the locations of these mixes
prior to commencement of marsh construction.
14.3.73
The proposed planting therefore
includes a relatively long list of native species to accommodate the likelihood
that not all planted species will necessarily thrive in the particular
conditions to be created. Thus the approach is to facilitate natural selection
as far as possible.
Table
14‑12 Species to be established in the Marsh Habitat area
(planting zones are shown in Appendix 14-3)
|
Mix
/ species
|
Total
area (m2)
|
Shoots
(number)
|
Density (m-2)
|
%
Cover
|
Minimum
height (mm)
|
|
|
|
|
|
|
|
|
1. Floating plants (permanently inundated)
|
|
Nymphaea
spp.
|
30
|
5
|
15
|
<1
|
|
|
Nelumbo
nucifera
|
30
|
5
|
15
|
<1
|
|
|
2. Permanently inundated mix
|
|
Vallisneria natans
|
5210
|
5
|
12
|
45
|
500
|
|
Ottelia alismoides
|
5210
|
5
|
12
|
45
|
500
|
|
Hydrilla verticillata
|
1160
|
5
|
20
|
10
|
500
|
|
3.
Reed bed
|
|
Phragmites
australis
|
16475
|
3
|
10
|
100
|
800
|
|
4.
Seasonally inundated mix A
|
|
Bacopa monnieri
|
690
|
5
|
20
|
25
|
150
|
|
Sagittaria trifolia
|
690
|
5
|
20
|
25
|
500
|
|
Polygonum barbatum
|
550
|
5
|
20
|
20
|
500
|
|
Eleocharis equisetina
|
827
|
5
|
20
|
30
|
300
|
|
5.
Seasonally inundated mix B
|
|
Eleocharis dulcis
|
550
|
5
|
20
|
20
|
300
|
|
Polygonum glabrum
|
680
|
5
|
20
|
25
|
300
|
|
Schoenoplectus mucronatus
|
827
|
5
|
20
|
30
|
600
|
|
Cyperus malaccensis
|
680
|
5
|
20
|
25
|
600
|
|
6.
Seasonally inundated mix C
|
|
Sagittaria guyanensis
|
827
|
5
|
16
|
30
|
500
|
|
Saururus chinensis
|
550
|
5
|
16
|
20
|
500
|
|
Eleocharis tetraquetra
|
690
|
5
|
16
|
25
|
500
|
|
Cyperus malaccensis var. brevifolius
|
690
|
5
|
16
|
25
|
500
|
|
7.
Seasonally inundated mix D
|
|
Ludwigia ascendens
|
960
|
5
|
16
|
35
|
500
|
|
Polygonum hydropiper
|
550
|
5
|
16
|
20
|
500
|
|
Polygonum juncundum
|
550
|
5
|
16
|
20
|
500
|
|
Colocasia esculenta
|
690
|
5
|
16
|
25
|
500
|
|
8.
Seasonal / grazed marsh mix E
|
|
Fimbristylis complanata
|
1810
|
5
|
12
|
20
|
400
|
|
Fimbristylis subbispicata
|
2270
|
5
|
12
|
25
|
400
|
|
Cyperus halpan
|
1810
|
5
|
12
|
20
|
400
|
|
Scirpus juncoides
|
1810
|
5
|
12
|
20
|
400
|
|
Fimbristylis nutans
|
1360
|
5
|
12
|
15
|
400
|
|
9.
Seasonal / grazed marsh mix F
|
|
Fimbristylis miliacea
|
1360
|
5
|
12
|
15
|
300
|
|
Fimbristylis ferruginea
|
1360
|
5
|
12
|
15
|
300
|
|
Fuirena umbellata
|
1810
|
5
|
12
|
20
|
300
|
|
Rumex japonicus
|
1810
|
5
|
12
|
20
|
300
|
|
Cyperus falbelliformis
|
1360
|
5
|
12
|
15
|
300
|
|
Scirpus littoralis
|
1360
|
5
|
12
|
15
|
300
|
|
10.
Mixed herbaceous
|
|
Fimbristylis ferruginea
|
1070
|
3
|
12
|
10
|
300
|
|
Scirpus juncoides
|
1600
|
3
|
12
|
15
|
300
|
|
Cyperus halpan
|
1600
|
3
|
12
|
15
|
300
|
|
Saururus chinensis
|
1600
|
3
|
12
|
15
|
300
|
|
Polygonum barbatum
|
1600
|
3
|
12
|
15
|
300
|
|
Eleocharis equisetina
|
1070
|
3
|
12
|
10
|
300
|
|
Nepenthes mirabilis
|
2140
|
3
|
12
|
20
|
200
|
|
11.
Herbaceous plants on aquaculture pond bund area
|
|
Leersia hexandra
|
TBC
|
5
|
12
|
30
|
500
|
|
Eragrostis unioloides
|
TBC
|
5
|
12
|
30
|
500
|
|
Lepironia articulata
|
TBC
|
5
|
12
|
40
|
500
|
|
12.
Bamboo clumps (planted at 50 cm
centres).
|
|
Bambusa vulgaris cv. Vittata
|
620
|
100
|
2000
|
|
Bambusa vulgaris cv. Wamin
|
620
|
100
|
2000
|
Note: At least 5% of the areas need to be
bare mud and water.
Access and Fencing
14.3.74 The Wetland Nature Reserve is designated as “Private Land Zone”
under the Ramsar Conservation Strategy and Management Plan as it is under
private ownership. Adjacent to it is a
band of Public Access Zone”. The proposed
Wetland Nature Reserve can be integrated with the “Public Access Zone” forming
a logical extension of this zone. Whilst
conservation is the prime objective of the Wetland Nature Reserve, limited
public access will be allowed on a restricted basis (prior booking will need to
be made with the reserve manager) so as not to create
disturbance to birds. Residents of the development will
not have privileged use of the WNR.
14.3.75 It is proposed that footpaths and hides will be provided in part of
the site. A plan of the indicative footpath network subject to detailed
design of the WNP is included Figure 14‑12. This shows
that the footpaths will be limited to the southwest and west of the site,
in order to:
·
avoid high levels of disturbance
in the core area of aquaculture ponds;
·
provide easy access to the
footpaths from the Site access; and,
·
include the full range of
habitats types within the site.
14.3.76 To further avoid disturbance to wildlife within the site, the
footpaths will be screened by tall vegetation or artificial screens where necessary. Footpaths
will be raised on board walks (an indicative design is included in Appendix
14-4) in the wetter and more sensitive habitats or follow existing bunds.
14.3.77 Hides will be built at a number of locations to provide view points
over the main habitat types on the site (lakes and reedbeds, freshwater marsh
and aquaculture ponds). A design for a hide is provided in Appendix 14-5.
14.3.78 Occasional guided tours (prior booking with the reserve manager will
be required) can also be provided. Some
educational facilities can be provided, including information boards at the
site entrance, inside hides and at appropriate locations alongside the
footpaths. These will provide basic information on the ecology and conservation
importance of the wetland habitats, information on the management and cultural
aspects of fish farming and its importance for wildlife.
14.3.79 The emphasis on access would be to provide simple 'low-key'
facilities that would primarily be used by people with an interest in natural
history. Picnicking and similar activities will not be allowed within the WNR.
The maximum number of visitors that can be accommodated without causing
unacceptable levels of disturbance could be
limited to the number of seats / space available in the hides. Discussions with the Reserve Manager at Mai Po indicate that a cautious
approach is appropriate and that, during the initial stages of WNR management,
visitor numbers are kept low. Numbers of visitors can be increased at the
discretion of the reserve manager as experience in the management of the WNR
grows.
14.3.80 Facilities for visitors will be kept to a minimum, but will include toilets,
a shelter with drinks machine and a small car park. The location of these
facilities is indicated in Figure
14‑12.
14.3.81 Vehicular access to the wetland mitigation areas will be restricted
by means of lockable gates to be located at appropriate positions.
14.3.82 The residential development works area will be screened off from the
rest of the site before the start of any works, to reduce disturbance to
wildlife in the surrounding area. Similarly the freshwater marsh area will be
screened off from the surrounding wetland areas during the wetland construction
works.
14.3.83 Screening will consist of solid hoarding of at least 2 m height.
Management facilities
14.3.84 A small office, storage, workshop area and quarters will be constructed
for the WNR Reserve Manager and his / her staff. These facilities will take the
form of small prefabricated buildings that can be placed in a convenient
location. The site for these facilities will be determined once the
construction of the WNR is completed. During construction the WNR Reserve
Manager will occupy a temporary facility the location of which will be
determined during planning for the construction works.
Management regime stages and programme
Interim
Management
14.4.1 To compensate for disturbance caused during the construction phase
of the residential development and the marsh habitat interim management will be
implemented to increase the attractiveness of unaffected ponds to wetland bird
Species of Conservation Importance.
14.4.2 Essentially interim management will involve artificially increasing
the carrying capacity of ponds for these species through works designed to
significantly increase the availability of prey species (trash fish). The
following specific actions, which have been implemented as appropriate
mitigation at similar sites elsewhere in Hong Kong
(eg Binnie, Black & Veatch 2002):
·
The fish populations within
ponds will vary greatly depending on previous management. A rapid assessment of
remaining populations will be carried out and ponds re-stocked, as required,
with trash fish species;
·
Initial and ongoing correction
of water quality, specifically pH to ensure appropriate conditions for fish
survival. Although trash fish species are relatively hardy compared to many
commercial fish, they can be affected by low pH conditions. If pH drops below
4.5 then peanut residue will be added to raise pH; and,
·
Rotational, partial drain down
of pairs ponds (excluding Ponds 2, 3 and 11). Once drained down each pair of
ponds will be maintained with shallow water < 30 cm deep for a period of 4 weeks.
14.4.3 Under traditional management the production of non-commercial
by-product, including prawns and fish, such as Tilapia, that are below
marketable weight is in the order of 260 kg/ha/year (See Section 12.4, Aspinwall, 1997 and
Primavera, 2000). To achieve the mitigation targets the availability of small
fish and prawns will need to be increased to provide enhanced feeding
opportunities. Experience from the implementation of a similar approach by KCRC
at Lok Ma Chau
indicates that optimal stocking densities are likely to be in the range 2-5
times the expected ‘normal’ biomass of trash fish, ie up to 1,300 kg/ha/year. Imported fish will comprise
small Tilapia (target weight approximately 50g / individual). A key reason for the relatively large increase in
stocking density is due to the fact increased prey availability benefits a wide
variety of piscivorous birds, including cormorants and ardeids, all of which
can be expected to increase in numbers within the mitigation area.
14.4.4 Reference to recent monitoring reports from monitoring of the Lok Ma Chau mitigation works (AEC
2003, 2004, 2006a, 2006b)
indicates that the densities implied for key species (Black-faced Spoonbill,
Chinese Pond Heron, Great Cormorant, Great Egret and Little Egret) are readily
achievable (and have been frequently exceeded). The experience at Lok Ma Chau also indicates that a
flexible (adaptive management) approach is required. The effectiveness of
mitigation requires careful attention to water quality, adjustment to stocking
densities, periodic review of the timing and duration of draw-down and
continuous monitoring.
14.4.5 Prior to the commencement of interim management a plan for pond
draw-down will be confirmed. This plan will specify the sequence of draw-down
ensuring that no pond is drawn-down more frequently than once per calendar
year. Particular attention will be given to the stability of re-profiling works
(some settling and adjustment is inevitable), the status of fish stocks and
water quality. The condition of newly planted Phragmites reeds and Paspalum
will also be monitored and remedial action taken as required to ensure they
fully establish.
14.4.6 Interim management will commence at an early stage of the
construction of the Residential Development and WNR as described in Section
13.9. In summary, however, the key stages are briefly described below, these
stages are shown graphically in Figure
13‑13 (dates shown are indicative):
Pre-Construction
Phase I (Jul ‘10– Sep ‘10)
14.4.7 During this phase the developer will take occupation of the site and
make preliminary preparations including erection of site fencing. No specific habitat
management is envisaged at this stage and all ponds will remain under their
current aquaculture regime. All ponds will potentially be available as habitat,
that is no ponds will be directly affected by construction activities.
Pre-Construction
Phase II (Oct ’10 – Mar ’11)
14.4.8 During this phase pond enhancement works will commence (see above).
To minimise disturbance and to maximise the extent of available habitat these
works will be undertaken progressively within Sector 1 (the extent of Sector I is approximately 20.4 ha). The works involved in enhancement
include the draining of adjacent ponds and the excavation of the intervening
bund. This will be done according to the construction plan of the Wetland
Nature Reserve. These works are similar to normal pond management activities
and are not in themselves expected to cause undue disturbance to birds,
nevertheless to minimise potential disturbance impacts, pond enhancement works
will be phased.
14.4.9 The maximum area of pond affected by these enhancement activities
during this Phase will be 4.2 ha
(representing the largest ponds that will be concurrently drained and
re-profiled). Prior to, and following enhancement works, the ponds will be
filled with water and are considered to be available as habitat for birds and
other Species of Conservation Importance.
14.4.10 During these works the ponds located within Sectors 2 (21.3 ha) and 3 (20.1 ha), the area proposed for marshland (14.4 ha) and development area (4.0 ha) will remain under their existing management
regime ensuring that, throughout this Phase, at least 76.0 ha of pond will remain as available.
Pre-Construction
Phase III (Apr ’11 – Sep ’11)
14.4.11 During this Phase enhancement works will commence in Sector 2 and
site clearance will commence in the Development Area. The enhancement works in
Sector 2 will follow the same pattern as described above, however, the maximum
area affected at any one time will be slightly larger at approximately 6.1 ha. Once the Development Area
clearance is complete a further, approximately, 4.0 ha of pond habitat will become
unavailable. During this Phase, therefore, the minimum pond area available as
habitat will be approximately 70.0 ha.
14.4.12 To compensate for this reduction in habitat area it is proposed to
commence interim management in the Sector 1 ponds (all of which were enhanced
in Phase II). The interim management strategy is to increase the carrying
capacity of ponds by drawing them down for longer periods than is normal under
traditional management and to artificially increase the availability of prey
species for wetland birds through stocking of trash fish species. The key
elements of the interim management plan include:
·
Management of water quality, specifically
pH to ensure appropriate conditions for fish survival. Although trash fish
species are relatively hardy compared to many commercial fish, they can be
affected by low pH conditions. If pH drops below 4.5 then the cause will be
investigated and appropriate steps taken to return pH to an appropriate level;
·
Rotational, partial drain down
of pair ponds. Once drained down each pair of ponds will be maintained with
shallow water < 30 cm deep
for a period of 4weeks;
·
Stocking of trash fish as
required to ensure that target carrying capacities are met; and,
·
Minimising human presence to
limit disturbance.
Pre-Construction
Phase IV (Oct ’11 – Mar ’12)
14.4.13 Interim management will continue at Sector 1 (20.4 ha) and commence at Sector 2 ponds (21.3 ha). In addition interim management will
also be implemented in Sector 3 ponds (20.1 ha, although these are yet to be enhanced). No
pond enhancement works will be undertaken during this Phase. Creation works
will commence within the marshland area, while site clearance continues in the
development area, making approximately 14.4 ha and 4.0 ha,
of pond area unavailable, respectively. Consequently a minimum of 61.8 ha of pond area will be available, all
of which will be under interim management.
14.4.14 During this phase the physical activities associated with marsh
creation works will be completed with planting taking place in the following
Phase.
Pre-Construction
Phase V (Apr ’12 – Sep ’12)
14.4.15 Interim management will continue at Sector 1 (20.4 ha) and 2 ponds (21.3 ha).
Ponds in Sector 3 will undergo enhancement occupying a maximum of 3.8 ha at any one time while the remaining 16.2 ha of pond area will be kept under
interim management. Planting of
marshland habitats will take place followed by approximately 12 months of
establishment. For the purposes of this assessment it is assumed during this
period that all the marshland habitat (14.4 ha) will be unavailable as habitat (although it
is actually likely that some species will begin to make use of it). Site
clearance and preparation works will continue in the development area (4.0 ha). Thus a minimum of 57.9 ha of pond area will be available, all
of which will be under interim management.
Pre-Construction
Phase VI (Oct ’12 – Jun ’13)
14.4.16 Marsh establishment will continue (and hence assumed to be
unavailable). Interim management will continue at Sector 1 (20.4 ha), 2 (21.3 ha) and 3 ponds (20.1 ha) resulting in a total area of available pond
area of 61.71 ha, all
of which is under interim management.
Construction
Phase (Jul ’13 – Sep ’16)
14.4.17 Construction works are programmed to commence in July 2013. During this phase all pond enhancement works
will be completed and a total area of 61.8 ha of ponds will be under interim management in
Sectors 1, 2 and 3. Marsh establishment
is expected to be substantially complete (although maturation will continue
over several additional years). Consequently there will be an additional 14.4 ha of marshland habitat available.
14.4.18 The commencement of construction works will result, however, in the
generation of substantially higher levels of noise and vibration and hence
disturbance than was experienced during Pre-Construction Phases. It is assumed,
therefore, that sections of wetland habitat adjacent to the construction area will
be functionally unavailable to species that are sensitive to disturbance. The
extent of these areas was assessed in Section 13.8 and are summarised in Figure 13‑12 and Table
13‑55.
14.4.19 The key strategy for mitigating these disturbance effects is to
maintain interim management in all of the enhanced Sector 1, 2 and 3 ponds. It
is anticipated that interim management will increase the carrying capacity of
these ponds sufficiently to off-set temporary functional habitat loss
associated with the displacement of birds from areas affected by construction
phase disturbance.
14.4.20 The objective, therefore, during this Phase is to provide habitat of
sufficient quality to maintain the numbers of birds observed during the
baseline. To gain an indication of the existing carrying capacity of the Fung
Lok Wai wetlands, the survey data obtained during the baseline survey were
analysed to identify the maximum number of birds recorded. These data were then
converted to densities by dividing the maximum number of individuals observed
within the within the Study Site by the extent of wetland in the Study Site
(approximately 80.1 ha). The
Study Site sits within a larger area of wetland habitat, for comparison this
table also shows the maximum and mean number of individuals of Species of
Conservation Importance observed within the total Assessment Area. These are
also shown as densities achieved by dividing the counts by the extent of
wetland within the Assessment Area (approximately 170.6 ha of wetland). These data are shown in Table 13‑59.
Marsh
construction and establishment
14.4.21 The Constructed Marsh Area and the Development Area are adjacent to
each other. This provides an opportunity for reducing disturbance associated
with construction by combining activities involved in heavy earthworks, such as
pond removal and site formation. These activities have, therefore, been
programmed to occur at the same time.
14.4.22 An additional advantage of the concurrence of these activities is
the ability to immediately relocate soil removed from the development area to
the marsh area where it can be used for site formation. This process obviates
the need for temporary storage areas for this material.
14.4.23 Once site formation works for the constructed marsh area have been
completed it is anticipated that top-soiling and ground shaping can be
completed within the same dry season. Planting works are programmed to commence
with the on-set of the wet season when the ground is moist, increasing the
likelihood of plant survival.
14.4.24 During the first twelve months after planting, the condition of
plants must be closely monitored. Any plants that die or fail to thrive should
be replaced. Any emerging weeds should be removed as soon as they are detected,
preferably by hand, but if they become established or otherwise difficult to
remove then limited application of appropriate herbicides should be considered
as a last resort. During the establishment period water levels must also be
closely monitored as these will have a significant bearing on the performance
of young plants.
14.4.25 Establishment management actions should be reviewed after the first
year.
Long-term management
Aquaculture pond management
14.4.26 During this phase all of the enhanced aquaculture ponds will be
managed according to the long-term management plan outlined below and their
performance monitored.
14.4.27 As described above the majority of the target species of
conservation occurring within the site benefit from traditional fish farming
activities. The enhancement of the aquaculture ponds within the mitigation area
will therefore include the continuation of active traditional fish farming
management in each on most of them.
14.4.28 In most respects aquaculture pond management will represent a
continuation of existing fish polyculture practices, which can be briefly
characterised as a three stage process:
·
Stocking – introduction of fish
as fingerlings or juveniles (as determined by availability) at a density of
about 14,000 fingerlings per hectare (lower for juveniles). The species stocked
also tend to be determined by market availability and price but typically
include carp (such as, for example, bighead, common carp, grass carp), mullet
(eg grey mullet) and Tilapia;
·
Rearing – Through the year fish
farmers typically add food to promote fish growth. The type of food added
depends on price, availability, stage of growth and the personal preferences of
the fish farmer, but could include, for example, corn meal, peanut cake, wheat
bran, rice bran, biscuit, brewery waste, soya bean and vegetation clippings. If
the pH of the pond drops then farmers will adjust water back to normal levels
through the addition of lime or peanut residue. The timing and quantity of such
additions is dependent entirely on water quality conditions. Aeration devices
may also be employed if oxygen levels fall below critical levels for fish
survival.
·
Harvesting – when fish are
ready for harvesting pond levels are dropped and fish captured. Commercial fish are removed and sold,
however, trash species will be left in the shallow water of the pond and these
form an excellent food source for birds such as herons and egrets.
14.4.29 The main long-term management enhancement of the ponds will be to
regulate and extend the period of draw-down for harvesting. Under current
fish-farming practices harvesting is carried out in winter by reducing the
water depth of the pond (by pumping water to another pond for storage) and the
gradual netting of the stock over a couple of weeks. However, the precise dates
of harvesting are dependent on market prices and this can result in
food-resource ‘bottle-necks’ if no or few ponds are drained at any one time.
Draw down of the ponds will therefore be carried out on a regular basis
irrespective of the market value of fish.
14.4.30 Draw-down periods will also be for a fixed time of 20 days. This is
longer than normal and will thus further increase feeding opportunities thereby
further reducing potential feeding bottle-necks.
14.4.31 It is also proposed that at any one time approximately 25% of the
aquaculture pond area will be taken out of production (on a rotational basis)
for one season. This will provide additional shallow water habitats that will
be used by targets species such as herons and egrets.
14.4.32 The operating water levels for each pond will be specified once
survey and re-profiling works have been completed. The following levels are to
be specified for each pond which are illustrated schematically in Figure 14‑14:
·
Initial Operating Level (IOL) level for
ponds when filled / refilled during the winter after drain-down or harvesting.
IOL is set so that water level is coincident with any shelves in the bund such
that created shallows are created. Typical IOLs for fish ponds would be in the
range 1.2 to 1.9m above
base.
·
Maximum Operating Level (MOL) indicate
the level above which water must be removed from the pond by sluice drainage or
pumping (off-site or to other ponds as appropriate). In practice the MOL will
be determined for each based on its the height and structural integrity.
Typically MOL would be in the range of IOL + 0.3m (+/- 0.1m).
·
The MOL for the rain fed ponds
will be more specific. Pond 2 will be set a max of 1.0m. Pond 3 will be set to a max depth of 0.5m from May to July, raised to 0.8m between August and April. Pond 11 will
be set to a max depth of 0.3m
from May to July, raised to 0.6m
between August and April.
·
Low Operating Level (LOL) is expressed
as a range within which pond level is maintained during periods of set-aside.
LOL range is typically 0.1-0.3 m
in order to maintain sufficient depth to prevent acid soil problems. Soil exposed to air may become acidic. If water
quality (and productivity) is affected by acidic leachate being flushed into
the pond by run-off then appropriate measures may be required to neutralise the
affects (such as, for example, application of lime or fertilizers).
14.4.33 If water levels exceed target levels, then water will be pumped to
other ponds for storage. Decisions on the use of excess water will be made by
the WNR Reserve Manager according to site conditions and requirements at the
time.
14.4.34 Water levels will be monitored (via a permanent gauge board in each pond)
at least weekly from the start of the trial, or within one day of heavy
rainfall events (i.e. > 100 mm
of rain in the NW Territories over 24 hours).
14.4.35 Ponds will be used in a 5 year rotational sequence of fish farming /
shallow set-aside ponds (with no fish stocking). Thus approximately six of
ponds will be set-aside from production in any one year, two of which will be
used as a contingency reservoir pond. The long-term management programme for
the aquaculture ponds (other than those ponds that are to be retained as
Rain-Fed ponds) is described below in Table
14‑13. The sequence of use of each pond is based on a start
in January of each year (with stocking) and assumes that all ponds have been
joined where intended and all water control structures have been installed.
14.4.36 The sequence of drain-down, harvesting and refilling for each set of
ponds is not of critical conservation management importance. This can therefore
be carried out as required to reduce pumping and water loss from the system.
14.4.37 When ponds are drained down for harvesting, water levels must be
maintained at or below Low Operating Levels for at least 20 days. No more than
two ponds may be drained-down for harvesting at any one time.
14.4.38 After year 5 it is likely that the sequence will be repeated, but
modifications may be made, as part of ongoing revisions of the Operational
Management Plan (see below), as a result of lessons learnt from the monitoring
of use of the ponds by target Species of Conservation Importance and their prey
populations.
Table 14‑13 Long-term pond management
(5 year cycle)
|
Pond
|
Year
1
|
Year
2
|
Year 3
|
Year 4
|
Year 5
|
|
1
|
Set-aside
|
Fish production (Fill from 7)
|
Fish production
|
Set-aside (Move to 6)
|
Fish production (Fill from 7)
|
|
4
|
Fish production
|
Set-aside (Move
to 5)
|
Fish production (Fill from 5)
|
Fish production
|
Fish production
|
|
5
|
Set-aside
|
Reservoir (Fill from 4)
|
Fish production (Move to 4)
|
Fish production
|
Set-aside (Move
to 9)
|
|
6
|
Fish production
|
Fish production
|
Set-aside (Move
to 7)
|
Fish production (Fill from 1)
|
Fish production
|
|
7
|
Fish production
|
Set-aside (Move
to 1)
|
Fish production (Fill from 6)
|
Fish production
|
Set-aside (Move
to 1)
|
|
8
|
Reservoir
|
Set-aside
(Move to 12)
|
Fish
production (Fill from 12)
|
Fish
production
|
Fish
production
|
|
9
|
Fish production
|
Fish production
|
Reservoir (Fill
from 13)
|
Set-aside (Move
to 12,13)
|
Fish production (Fill from 5)
|
|
10
|
Fish production
|
Fish production
|
Fish production
|
Reservoir (Fill from 14)
|
Fish production (Move to 14)
|
|
12
|
Set-aside
|
Fish production (Fill from 8)
|
Set-aside (Move to 8)
|
Fish production (Fill from 9)
|
Fish production
|
|
13
|
Fish production
|
Fish production
|
Set-aside(Move to 9)
|
Fish production (Fill from 9)
|
Fish production
|
|
14
|
Fish
production
|
Fish
production
|
Fish
production
|
Set-aside
(Move to 10)
|
Fish
production (Fill from 10)
|
|
15
|
Set-aside
|
Fish production (Fill from 16)
|
Fish production
|
Fish production
|
Reservoir (Fill from 17)
|
|
16
|
Reservoir
|
Fish production (Move to 15)
|
Set-aside (Move
to 18)
|
Fish production (Fill from 18)
|
Fish production
|
|
17
|
Fish production
|
Reservoir (Fill from 18)
|
Fish production (Move to 18)
|
Fish production
|
Set-aside (Move
to 15)
|
|
18
|
Fish production
|
Set-aside (Move to 17)
|
Reservoir (Fill from 16, 17)
|
Fish production (Move to 16)
|
Set-aside (Move to 19)
|
|
19
|
Fish
production
|
Fish
production
|
Fish
production
|
Fish
production
|
Reservoir
(Fill from 18)
|
|
20
|
Fish production
|
Fish production
|
Fish production
|
Reservoir (Fill from 21)
|
Fish production (Move to 21)
|
|
21
|
Fish production
|
Fish production
|
Fish production
|
Set-aside (Move to 20)
|
Fish production (Fill from 20)
|
Note:
Refer to Fig 14-1 for the location of ponds
Set-aside
Maintain within LOL limits.
Empty and allow to dry for 30 days between 1 October and 15 December.
Fish
production
Stock between 1 January and
1 March. Drain down to LOL for at least
20 days and harvest 1 November – 14 February (of subsequent year).
Reservoir
Maintain water levels up to Max Level
through year. Use as storage pond and for maintaining target levels in other
ponds if necessary
Table 14‑14 General management actions for the Fung Lok Wai WNR
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Removal / substitution of exotic / undesirable invasive plants
(weeding)
|
|
|
|
|
|
Pest control
|
|
|
|
|
|
Selective cutting or pruning and removal
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Other management actions
14.4.39 Other management actions to be taken over the WNR area are outlined
in Table 14‑14.
14.4.40 Water levels will be adjusted within the freshwater marsh according
to year to year site conditions and ecological requirements for target species.
These target water levels will be set by a suitably qualified ecologist within
the site management team after inspection of the site and water monitoring
data.
14.4.41 Water levels may be allowed to drop to below ground level to allow
access for maintenance when necessary.
14.4.42 In addition to the management of the fish farming system, some
management of the aquaculture pond bund vegetation will also be undertaken.
This will mainly involve the control of tall vegetation such as reeds. Although
some patches of reed should be encouraged to develop for cover and screening
purposes these must be controlled as ponds that are enclosed by tall vegetation
tend to be avoided by many of the larger herons and egrets.
14.4.43 Management will also be carried out of undesirable invasive weeds if
necessary.
14.4.44 Vegetation shall only be removed by cutting and removal of roots /
rhizomes by hand or machine (e.g. backhoe). The use of herbicides will not be
allowed, unless deemed to be necessary (e.g. for treating some invasive
species) by the WNR Reserve Manager in consultation with an appropriately
qualified ecologist.
14.4.45 Grass clippings can be placed in fish ponds as a feed supplement for
herbivorous fish such as carp, however, more substantial vegetation will be
disposed of off-site in an appropriate manner.
14.4.46 Great Cormorant are known to predate upon fish within aquaculture
ponds. The level of predation predicted in the EIA was not considered to be
significant in terms of the ability of the WNR to achieve its conservation
targets, primarily because the mitigation targets for this species are
relatively low. During the operational phase the target density is 0.08 birds
ha-1. Nevertheless, the level of predation will be monitored and
appropriate (non-lethal) measures implemented to limit predation if it reaches
unsustainable levels. Non-lethal measures could include, for example, wires
spaced at between 5m and 7.5m. This is known to be effective at
deterring cormorants, and has been used successfully at carp ponds of up to 4ha in size. Wires would be used selectively
within ponds to balance the need for fish production and to maintain population
levels for the purposes of achieving mitigation targets.
Responsibilities
14.4.47 The management arrangements for the WNR are addressed in more detail
at Section 15.
Operational Management Plan
14.4.49
Once the WNR is operational the
HCMP will be replaced by an Operational Management Plan (OMP) with detailed
specifications and timings for management actions during long-term management.
The OMP will take into account any modifications that were found to be
necessary in the design and establishment methods used for creating the
habitats, the degree of success in establishing the habitats and any changes in
the factors affecting them. Management actions will also need to respond
appropriately to the outcome of monitoring where it is found that Action Levels
and Limits as defined in Section 14.5 are exceeded.
14.4.50
The OMP will be a working
document and reviewed annually, so that proposed actions are modified according
to progress, monitoring results and other relevant events. The OMP will be
thoroughly revised every five years. The five-year revision will include a
through analysis of all monitoring data and a review of the vegetation
communities that have established, with an identification of areas to be
cleared and replanted.
14.4.51
Reviews of the OMP and
monitoring results will be signed off by the relevant authority under the EIAO.
Contingency measures
14.4.52 Measures have been included in the design, construction methods,
management and monitoring proposals that aim to ensure the successful
establishment and long-term sustainability of the wetland as effective
compensation habitat for key target species.
14.4.53 The wetland designs also have in built contingency measures for key
factors affecting wetland establishment, especially regarding water supply,
water retention and plant establishment. These include:
·
The collection and storage of
water from the surrounding catchment and site run-off to supplement direct
rainfall supplies to the freshwater marsh area.
·
The use of fishponds as
reservoirs (on a rotational basis) to maintain water levels within target
tolerances if required (a practice not normally deemed necessary by fish pond
operators)
·
The use of a clay base liner if
tests indicate that water losses from the freshwater marsh wetland are outside
tolerable limits. Further potential contingency actions if required could
include placement of impermeable membranes in specific problem areas or
insertion of vertical plates (or membranes) at the edge of the wetland to
reduce lateral seepage.
·
High planting densities to
accommodate poor plant survival (and reduce potential weed growth).
14.4.54 Routine construction and establishment phase and long-term
management actions, such as weed clearance, replanting, thinning and water
level control will also be undertaken. These also aim to ensure the successful
establishment and long-term sustainability of the wetland cells.
14.4.55 In addition, specific contingency actions will be defined in a
Contingency Action Plan (to be prepared by the Contractor prior to the
development of the wetland construction Method Statement) and agreed before
commencement of works. As a minimum, contingency measures will be prepared for
potential:
·
inadequate water supply;
·
failure of water pumping
system;
·
damage to sluices and drainage
structures;
·
pollution of water supply;
·
direct pollution of wetland
cells by toxic substances (e.g. from spillage’s / dumping);
·
unacceptable plant survival
rate or growth during the 2 year establishment phase;
·
invasion by exotic or other
undesirable plant species;
·
flooding of the site and other
potential effects from storm events.
14.4.56 Intensive monitoring will be carried out of the physical and
ecological performance of the wetland mitigation area during the construction
and establishment phases and in the long-term. The monitoring will be carried
out in relation to defined “Action Levels” and “Limits” (see Section 14.5)
which trigger appropriate actions to rectify problems. Where necessary these
will include actions defined in the Contingency Action Plan.
General requirements
14.5.1 The following sections outline the monitoring requirements to ensure
that the WNR is achieving its objectives during the various phases of its
operation.
14.5.2 The start of the construction phase is dependent on the approval of
the EIA and the preparation of a detailed project timetable. Detailed
ecological monitoring will be undertaken from the commencement of works subject
to the preparation of a detailed Environmental Monitoring and Audit Manual.It
is intended that the data obtained from monitoring will inform the adaptive
management of the WNR, consequently it is important that there is flexibility
in the variables that are measured, the frequency and timing of survey and the
methods used. The monitoring programme will, therefore, be reviewed
periodically to ensure that it is achieving its aims.
14.5.3 After completion of the lease modification/land exchange, an
environmental committee will be set up to advise on and monitor the
effectiveness of the proposed mitigation measures of the construction of the
Project according to the HCMP and the EIA report. The function and membership of the
environmental committee shall be in line with those of the Lok Ma Chau Spur Line project. A list of members and terms of reference of
the environmental committee shall be submitted to the Director of Environmental
Protection for prior approval.
14.5.4 The key criteria by which the success of mitigation will be assessed
are the provision of appropriate habitats and the maintenance of populations of
Species of Conservation Importance. The specific targets for habitats and
species are summarised in Section 14.2 above.
14.5.5 During the construction and operation phase a monitoring programme
will be carried out of the ecological attributes proposed in Table 14‑15 according to the EM & A Manual The schedule shall
be reviewed, updated and revised prior to construction and operation of the WNR
for the approval of the relevant authorities. Once construction is
completed monitoring will also be undertaken during the long-term operation of
the WNR. Prior to the implementation of long-term monitoring, survey methods
and frequency will be reviewed in light of the outcomes of construction phase
monitoring.
Table 14‑15 Ecological monitoring programme
for Fung Lok Wai WNR
|
Ecological
attribute
|
Number of
measurements
|
Timing
|
Frequency of measurement
|
|
|
|
|
Construction
phase
|
Long-term
management phase
|
|
Habitats
|
|
|
|
|
|
Vegetation
map
|
All
of WNR
|
|
On
completion of construction works
|
After
completion of construction works survey every 6 months (wet and dry season) for first 5 years at
which point frequency of survey will be reviewed
|
|
|
|
|
|
|
|
Plant species
|
|
|
|
|
|
Survival,
health and growth of plant species planted
|
Aquaculture ponds:
Visual
assessment of all areas
|
|
Monthly
for one year on completion of enhancement works
|
Annually
thereafter
|
|
Constructed marsh habitat:
100
randomly marked plants in each planting zone
|
|
Weekly
for first 2 months after planting, then monthly for remainder of the first
year
|
Quarterly
in second year after planting then annually thereafter
|
|
Plant
species richness, relative abundance and cover
Frequency
and cover of alien and invasive plant species
|
Aquaculture ponds:
Continuous
visual assessment
|
|
Continuous
|
Continuous
|
|
Constructed marsh habitats:
Ten
1m x 1m quadrats per planting zone
Continual
visual assessment of alien and invasive species abundance will also be
conducted by the WNR management staff
|
|
6
monthly during establishment
|
6
monthly (wet and dry season) for first 5 years at which point frequency of
survey will be reviewed
|
|
Dragonflies:
species richness and abundance
|
Establish
representative transects throughout WNR
|
|
During
interim management period: Monthly during March, September, October and
November. Twice monthly during April – August
|
During
long-term management period: Monthly during March, September, October and
November. Twice monthly during April – August. Frequency of monitoring to be
reviewed after 5 years.
|
|
Aquatic invertebrates:
species richness and abundance
|
Aquaculture ponds:
Five
benthic cores and dip nets within 5 fish ponds
|
|
Annually
during interim management period
|
Annually
|
|
Constructed marsh habitat:
Five
benthic cores and dip nets at five locations
|
|
During
establishment: 6 monthly during wet and dry season
|
Thereafter
6 monthly during wet and dry seasons.
Frequency
of monitoring to be reviewed after 5 years.
|
|
Freshwater fish:
species richness and abundance
|
Aquaculture ponds:
Record
species, abundance, average length and average mass of all species removed at
harvesting
|
|
Every
two months (throw and drag netting) during interim management period
|
Annually
at harvesting and every two months (throw and drag netting).
Frequency
of monitoring to be reviewed after 5 years.
|
|
|
Constructed marsh habitat:
Netting
within representative areas of the permanent marsh
|
|
Every
two months (throw and drag netting) during establishment
|
Thereafter
every two months (throw and drag netting).
Frequency
of monitoring to be reviewed after 5 years.
|
|
Amphibians:
species richness and abundance
|
Establish
representative transects throughout WNR
|
|
During
interim management period: monthly during period April - November
|
Thereafter
monthly during period April – November.
Frequency
of monitoring to be reviewed after 5 years.
|
|
Reptiles:
species richness and abundance
|
Establish
representative transects throughout WNR
|
|
During
interim management period: monthly during period April - November
|
Thereafter
monthly during period April – November.
Frequency
of monitoring to be reviewed after 5 years.
|
|
Birds:
species richness and abundance
(see
above for specific details on bird monitoring)
|
Aquaculture ponds:
Each
pond
|
|
Weekly
during interim management period
|
Weekly
monitoring supplemented by opportunistic records at other times. More
frequent monitoring may be required during specific mamagement activities (eg
pond draw down)
|
|
Constructed marsh habitat:
Each
marsh type (ie seasonal marsh and permanent marsh)
|
|
Weekly
during interim management period
|
Weekly
monitoring supplemented by opportunistic records at other times
|
|
Hydrology
|
|
|
|
|
|
Water
surface level
|
Aquaculture ponds:
One
gauge board per pond
|
|
Daily
during interim management period
|
Weekly
and after heavy rain
|
|
Constructed marsh habitat:
Two
gauge boards per marsh type
|
|
Daily
during establishment
|
Weekly
and after heavy rain
|
|
Water chemistry
|
|
|
|
|
|
Water
quality variables:
pH
BOD
DO
Ammonia
concentration
Conductivity
Turbidity
Temperature
Suspended
solids
Salinity
|
Aquaculture ponds
|
|
Monthly
during interim management period
|
Monthly
|
|
Constructed marsh habitat:
At
representative locations within each marsh habitat
|
|
Monthly
during establishment
|
Monthly
|
|
Water
quality variables:
Total
oxidised nitrogen
Total
phosphorus concentration
Orthophosphate
concentration
|
Aquaculture ponds
|
|
Once
on completion of enhancement works
|
Monthly
for first year at which point frequency will be reviewed
|
|
Constructed marsh habitat:
At
representative locations within each marsh habitat
|
|
Once
on completion of construction works
|
Monthly
for first year at which point frequency will be reviewed
|
|
Heavy metals (Cadmium, Copper, Nickel,
Lead, Zinc, Mercury)
|
Aquaculture ponds:
Representative
aquaculture ponds adjacent to the active construction area
|
|
Once
on completion of works
|
Annually
thereafter
|
|
Constructed marsh habitat:
At
representative locations within each marsh habitat
|
|
Once
on completion of works
|
Annually
thereafter
|
Reporting
14.5.6 All data recorded during monitoring will be recorded on standardised
pro formas. Each year a summary report will be produced by the WNR Reserve
Manager detailing the outcomes of monitoring and indicating any remedial
actions taken or required.
Event and action plan for ecological attributes
14.5.7 The results of the ecological monitoring shall be compared with
Action Levels and Limits detailed in Table
14‑16 and corrective actions taken accordingly.
14.6.1 This is a draft document and key details presented here, including,
for example, stocking densities and monitoring requirements are to be finalised
subject to the endorsement of AFCD or other appropriate authority. The frameworks for such details are given in this section below and if
changes are required in light of the changing environment / baseline, such
changes would need to be agreed with AFCD or relevant authorities. This draft HCMP shall, therefore, be reviewed, updated and revised
prior to the construction of the WNR and submitted for the approval of the
relevant authorities.
14.6.2 The regime documented in the HCMP (and during the operational phase,
the OMP) will be reviewed on an ongoing basis, for example, every 5 years (or as
otherwise required) and submitted for approval by the relevant authorities.
14.6.3 An annual monitoring report detailing the results of monitoring
undertaken as outlined in Section 14.5, the achievement of objectives and any
adaptive modifications to the HCMP (or OMP) and its objectives will be reviewed
and submitted for approval by the appropriate authorities.
Table 14‑16 Key Action Levels and
Limits and their associated management actions
|
|
Action level
|
Action
|
Limit
|
Action
|
|
Plant
species
|
|
|
|
|
|
Survival, health and growth of plant
species planted
|
<75% survival of any planted species
|
|
<30% survival of any planted species
|
Implement contingency plan
|
|
> 10% fungal or pest infestation of
any species with >50% loss of vegetative growth
|
|
> 30% fungal or pest infestation of
any species with >50% loss of vegetative growth
|
|
Plant species richness, relative
abundance and cover
|
<75% species survival within planted
areas
|
|
<50% species survival
|
|
Plant community composition
|
Wetland plant species comprise <95% of
vegetation
|
|
Wetland plant species comprise <90% of
vegetation
|
|
Frequency or cover of any individual
species is <50% or >200% of proportion allocated in planting plan
|
|
Frequency or cover of any individual
species is <10% or >1000% of proportion allocated in planting plan
|
|
Frequency and cover of alien and invasive
plant species
|
Alien species >5% of total cover
|
|
Alien species >10% of total cover
|
Remove or utilise limited spot spraying of
appropriate herbicide on direction of WNR Reserve Manager
|
|
Animal
species
|
|
|
|
|
|
Dragonflies:
species richness and abundance
|
No increase from baseline over 2
consecutive years
|
|
Decline from baseline over 2 consecutive
years
|
Investigate causes and review management
actions
|
|
Aquatic
invertebrates: species richness and abundance
|
Establish action levels after 2 years of
monitoring*
|
|
Establish action levels after 2 years of
monitoring*
|
|
|
Freshwater
fish: species richness and abundance
|
Establish action levels after 2 years of
monitoring*
|
|
Establish action levels after 2 years of
monitoring*
|
|
|
Amphibians:
species richness and abundance
|
No increase from baseline over 2
consecutive years
|
|
Decline from baseline over 2 consecutive
years
|
Investigate causes and review management
actions
|
|
Reptiles:
species richness and abundance
|
No increase from baseline over 2
consecutive years
|
|
Decline from baseline over 2 consecutive
years
|
Investigate causes and review management
actions
|
|
Birds:
species richness and abundance
Provisional: These actions and levels to
be agreed with AFCD
|
Aquaculture
ponds:
<50% baseline richness and / or
abundance in one year
OR
<80% baseline richness and / or
abundance for 3 consecutive years
|
|
<50% baseline richness and / or
abundance for 3 consecutive years
|
Construction phase
Undertake detailed
investigation of causes. Reduce
disturbance effects caused by construction (eg noise) until causes identified
Operation phase
Undertake detailed
investigation of causes. Implement short-term management actions aimed at
increasing numbers
|
|
Constructed
marsh habitat:
Establish action levels after 2 years of
monitoring*
|
|
Establish action levels after 2 years of
monitoring*
|
Establish action levels after 2 years of
monitoring*
|
|
Hydrology
|
|
|
|
|
|
Water surface level
|
Aquaculture
pond:
Level >100mm above or below target
|
Adjust as required
|
Aquaculture
pond:
Level >200mm above or below target
|
Review levels, implement
contingency plan
|
|
Constructed
marsh habitat:
Level > 25mm above or below target
|
Constructed
marsh habitat:
Level > 100mm above or below target
|
|
Water
chemistry
|
|
|
|
|
|
pH
|
Outside range 5.5 – 7.5
|
Double water quality and vegetation
survival rate monitoring, identify problem and implement plan to rectify
|
Outside range 4 – 8
|
Identify alternative water
source until problem is rectified
|
|
BOD
|
>6.0mg/l
|
>9mg/l
|
|
DO
|
Within the ranges 51-70% or 121-130%
saturation
|
<50% or >130% saturation
|
|
Ammonia concentration
|
>2mg/l
|
>5mg/l
|
|
Salinity
|
>1ppt
|
>3ppt
|
|
Total oxidised nitrogen
|
>3mg/l
|
>10mg/l
|
|
Total phosphorus concentration
|
>1mg/l
|
>3mg/l
|
|
Orthophosphate concentration
|
>0.1mg/l
|
1mg/l
|
Note: * - The action levels and actions
will be established after 2 years for the communities of those species groups
(ie aquatic invertebrates, freshwater fish and marsh bird species) which are
currently not features of the existing FLW fauna. That is action levels and
actions can only be established once the communities have become established
and it becomes clear what their composition and relative abundance is.
1.
Anon. (2005). Summer 2005
Report: Egretry Counts in Hong Kongwith particular reference to the Mai Po
Inner Deep Bay Ramsar Site. Report by Hong Kong Bird Watching Society to the
Agriculture, Fisheries and Conservation Department, Hong Kong Special
Administrative Region Government.
2.
Asia Ecological Consultants Ltd (AEC) (2003). Wetland Compensation Area
Ecological Monitoring and Adaptive Management Advice. Annual Report, November
2003.
3.
Asia Ecological Consultants Ltd (AEC) (2004). Wetland Compensation Area
Ecological Monitoring and Adaptive Management Advice. Annual Report, October
2004.
4.
Asia Ecological Consultants Ltd (AEC) (2006a). Wetland Compensation Area
Ecological Monitoring and Adaptive Management Advice. 2004 – 2005 Annual
Report, March 2006.
5.
Asia Ecological Consultants Ltd (AEC) (2006b). Wetland Compensation Area
Ecological Monitoring and Adaptive Management Advice. Supplementary Report for
August – December 2005. March 2006.
6.
Aspinwall (1997). Study on the
Ecological Value of fish Ponds in Deep Bay Area: Executive Summary. Planning
Department, Hong Kong SAR Government.
7.
Aspinwall Clouston &
Wetlands International – Asia Pacific (1997).
Development of a comprehensive conservation strategy and a management plan in
relation to the listing of Mai Po and Inner Deep Bay as a Wetland of International
Importance under the Ramsar Convention.
Agreement No. CE47/95.
8.
Australian and New Zealand
Environment and Conservation Council, State of the Environment Reporting Task
Force (ANZECC) (2000). Core environmental indicators for reporting on the
state of the environment, Environment Australia, Canberra.
9.
Benstead P., Drake M., José P.,
Mountford O., Newbold C., and Treweek J. (1997). The wet grassland guide:
managing floodplain and coastal wet grasslands for wildlife. RSPB, Sandy.
10.
Benstead P., José P., Joyce C.
and Wade M. (1999). European wet grassland: guidelines for management and
restoration. RSPB, Sandy.
11.
Binnie, Black & Veatch
(BBV) (2002). Sheung Shui To Lok Ma Chau Spur Line Environmental Impact
Assessment Report. Kowloon Canton Railway Corporation, January 2002.
12.
Binnie Consultants Limited
(1997). Reconnaissance survey of benthic and pelagic fishpond fauna at Fung Lok
Wai. Unpublished report.
13.
Environment Protection
Department (2002). River Water Quality in Hong Kong
in 2000. Water Policy and Planning Group, Environmental Protection Department. Hong Kong Special Administrative Region Government. Feb
2002.
14.
Hawke C. J. and José P. V.
(1996). Reedbed management for commercial and wildlife interests. RSPB, Sandy.
15.
Holling, C. S. (ed) (1978).
Adaptive environmental assessment and management. John Wiley, Chichester.
16.
McMullon C. and Collins T.
(2004). Habitat compensation and flood management: criteria and issues to be
addressed in the design and delivery of compensation packages. Proceedings of
the 39th Flood and Coastal Management Conference, July 2004. DEFRA,
UK Government, London.
17.
Missouri Department of Natural
Resources (1996). Water quality standards. Missouri Department of Natural
Resources, Clean Water Commission, Jefferson
City, MO.
18.
Primavera, J.H. (2000).
Integrated Mangrove – Aquaculture Systems in Asia.
Integrated Coastal Zone Management, Autumn edition, pp. 121-130.
19.
Townland Consultants Ltd, Wong
Tung & Partners Ltd, Maunsell Consultants Asia Ltd, MVA Asia Ltd, CES Asia
Ltd, Belt Collins & Associates HK ltd, Nelson and Wright (1992). Sunnyville
Estate development at Nam Sang Wai, Engineering Assessment Report, Nam Sang Wai
Development Co, Ltd & Kleener Investment Ltd.
20.
USEPA (1983). Water Planning Division.
Results of the Nationwide Urban Runoff Program - Volume 1, Final Report. [Washington, DC],
USEPA P1384-185552.
21.
Walters, C. J. (1986). Adaptive
management of renewable resources. Macmillan,
New York.
22.
Wilson, K.D.P.
(1995). Hong Kong Dragonflies, Urban Council of Hong Kong,
15.
The Long-term Management OF the Wetland NAture Reserve
15.1.1
The Fung Lok Wai site comprises
approximately 80.1 hectares of which approximately 4.0 hectares (5%) will be
affected by the residential development and associated access roads. The
remaining approximately 76.1 hectares (excluding the access road) will form the
Wetland Nature Reserve (WNR).
15.1.2 The
project proponent shall be responsible for the creation, enhancementand
management of the WNR during the construction phase and shall provide an
undertaking to take sole responsibility for management until a successor can be
found to the satisfaction of EPD or its agents. Section 3.5.6.4
(xv) of the EIA study brief for this proposal (EPD, 2000) requires the project
proponent to propose a management package for the WNR with particular attention
to:
·
The habitat management plan and
specification of resources requirement for its implementation (this is addressed
separately within the Fung Lok Wai Wetland Nature Reserve Habitat Creation and
Management Plan [HCMP]);
·
The long-term trust management
system with management guidelines;
·
The financial arrangements to
sustain the management of the wetland;
·
The management agents and their
responsibility; and,
·
A contingency plan for the
management of the WNR before the establishment of foundation management.
15.2.1
The design of the WNR,
construction methods and programme and its long-term management plan are
detailed in Section 14 of this report. The following is a brief summary of key
design, construction and management arrangements proposed.
15.2.2
Approximately 61.7 ha of the
existing fish ponds at Fung Lok Wai will be modified and enhanced to increase
their value for Species of Conservation Importance, particularly birds recorded
regularly on the site.
15.2.3
Out of these modified and
enhanced fish ponds, five (10.3 ha) of the existing fish ponds will be
consolidated into three and permanently set aside and planted, to varying
degrees, with reeds (Phragmites australis)
to provide attractive habitat for water birds, particularly duck and reedbed
passerines. These ponds will be fed by rain water and their level allowed to
fluctuate seasonally.
15.2.4
The remaining fishponds will be
consolidated through bund removal to create 18 ponds with an average size of
about 2.6 ha. These ponds will undergo a series of enhancement to improve their
attractiveness to wildlife, particularly birds including: creation of shallows
and muddy islands through re-distribution of bund material; and, cut back of
vegetation.
15.2.5
A potential alternative egretry
will be constructed in a part of the WNR that is as remote as possible to
minimise disturbance. The design of this egretry draws on information gathered
about the key features of egretries within the New Territories which indicates,
for example, that it should be constructed with mature specimens of species
such as Figs (Ficus spp.), Celtis sinensis and bamboo (Bambusa spp.).
15.2.6
Whilst the WNR is being
constructed most of the fishponds will be managed according to an interim
management regime which is intended to boost their immediate value to feeding
birds. Construction of the WNR will be undertaken in stages to minimise
disturbance to bird populations.
15.2.7
Following completion of the
construction of the Residential Development the enlarged ponds will be managed
according to traditional commercial aquaculture procedures involving stocking,
rearing, harvesting and periodic set-aside for maintenance and recovery with
several key differences:
·
The management of the 18
enlarged and enhanced ponds for active production will be coordinated. Most
farmers typically operate a handful of ponds at the same time. The management
of such a large block of ponds en masse will allow for a coordinated approach
to fish production, maintenance and monitoring activities. It will also
facilitate a more effective approach to their adaptive management.
·
Ponds in production will be
drained down annually for a fixed period of 20 days. Ponds are typically drawn
down for shorter periods under normal management regimes.
·
Approximately 25% of ponds will
be “set-aside” for production according to a 5 yearly schedule. This will
provide opportunity for maintenance works and allow for control of diseases or
presence of undesirable species. Set-aside is a more ad hoc process under
normal management procedures.
·
Whilst most fish selected for
farming will be those typical of commercial aquaculture operations, the
composition and proportions of these species will be varied to benefit feeding
wildlife.
15.2.8
An area of approximately 14.4
ha adjacent to the development area will be converted into a complex of
freshwater marsh habitats. This area will comprise:
·
Permanent marsh composed of a
series of shallow inter-locking lakes with occasional deep areas and islands.
Fringe vegetation in the form of reeds and other emergent plants will create
cover for birds and other fauna.
·
Seasonal marsh composed of
vegetation that is inundated only during the wet season. Annual grazing by
water buffalo will maintain vegetation height and provide small scale habitat
disturbance.
·
Storage pond. The water deficit
usually experienced every dry season is a constraint on the design and
management of marsh habitats. To ensure a supply of freshwater of suitable
quality for the permanent marsh throughout the year an existing fishpond will
be enlarged to provide storage. The optimum size of this storage has been
established through modelling of typical and extreme rainfall patterns.
15.2.9
Water levels within the marsh
complex will be managed according to broad habitat requirements – ie permanent
or seasonal inundation. Within the permanently inundated marsh areas, levels
will still be allowed to fluctuate (within bounds) to facilitate the periodic
exposure of muddy areas.
15.2.10
Native plant species mixes have
been selected on the basis of the specific hydrological conditions envisaged
for each area of the marsh complex. It is anticipated that, on completion of
construction and planting works, it will take 12 months to establish the marsh
habitats.
15.2.11
The WNR shall not be used for
any other purposes except for those specified in the HCMP.
15.3
Management of the Wetland Nature Reserve
15.3.1
The WNR area will be managed by
the project proponent and suitably qualified consultants will be appointed to
oversee construction works.
15.3.2
Upon the completion of the
construction of the WNR, the Development Site will be sub-divided into two
portions: the WNR portion and the
residential portion. The operation and
management of the WNR will be independent from the management of the
residential development. The WNR will be
managed by the proponent until a designated successor such as an independent
Foundation is identified to the satisfaction of EPD or its agents.. The residential development, which will be
under strata-titled ownership will be independently managed by the property
manager appointed by the owners of the residential development. The residents in the residential development
will neither have privilege over the general public for access to the WNR nor
the liability of its maintenance.
15.3.3
An appropriately trained ecologist or a
reputable organisation
with a significant level of experience in the management of wetland habitats
will be employed as the Reserve Manager for the day-to-day management of the
WNR. Experienced fish farmers will be employed for the operation of the fish
ponds under the supervision and guidance of the Reserve Manager. The Reserve Manager will oversee and advise on construction and
enhancement works to ensure that they meet conservation objectives. The Reserve
Manager will also coordinate monitoring and implement actions as detailed in
the HCMP during this time.
15.3.4
The Reserve Manager will
coordinate fish pond management in line with the interim and enhanced
management protocols established in the HCMP.
15.3.5
Once the WNR is fully
operational the HCMP will be replaced by an Operational Management Plan (OMP,
see Section 14.4.49) and it will be the responsibility of the Reserve Manager
to implement the management and monitoring protocols detailed in that document.
15.3.6
The project proponent shall
provide an undertaking to take sole responsibility for the management of the
WNR until a designated successor is identified to the satisfaction of EPD or
its agents. Subject to the necessary agreements from relevant Government authorties
outside the EIA Ordinance which shall be obtained by the proponent separately,
an independent, non-profit Foundation will be established to take over the
long-term management of the WNR and the Environmetnal Permit will be
transferred to the Foundation. Similar in form to a Conservation Trust, the
Foundation will provide guidance and resoures on strategic and day-to-day
management of the reserve. Until such time the Foundation takes over
responsibility for the long term management and maintenance of the WNR. A
proposal of the structure, operation and financing of the Foundation is set out
at the Annex of this report. It is recognized that approval of
the EIA report would not represent Government’s endorsement or agreement of the
Foundation proposal. Upon receipt of the necessary agreement from government, the
WNR will be assigned to the Foundation.
15.4.1
The project proponent will be responsible for the proper management and
operation of the WNR until a designated successor such as an independent
Foundation is identified to the satisfaction of EPD or its agents. In the long
run, an independent Foundation will provide a sound mechanism for overseeing
the management of the WNR. The Foundation will:
·
Provide an effective
management framework for the implementation of the WNR Habitat Creation and
Management Plan including update in light of new understanding of the ecology
of the wetland habitats of the reserve (adaptive management);
·
Provide resources in the form
of personnel and financial support to ensure that conservation targets are met;
and,
·
Coordinate a rigorous
monitoring programme to ensure that Conservation Targets are being met and to
improve understanding of the wetland ecology of the reserve.
15.4.2
The Foundation represents a practical step toward, and a model for,
sustainable development in Hong Kong.
16.1.1
An Environmental Monitoring and Audit (EM&A) Manual has been
prepared under a separate cover as part of the EIA study. The recommended EM&A programme is only
discussed in brief here. For further
details on the EM&A, the Manual should be referred to.
16.1.2
In accordance with the requirements in Section 3.5.12 of the EIA Study
Brief, an Implementation Schedule of the environmental mitigation measures
recommended in the EIA study has been prepared in form of a checklist. The Implementation Schedule is given in the
EM&A Manual under a separate cover.
16.2.1
The objectives of the implementation of EM&A for the Project are to:
·
Provide an early indication
should any of the environmental control measures or practices fail to achieve
acceptable standards;
·
Determine project compliance
with regulatory requirements and standards;
·
Verify the environmental
impacts predicted in the EIA Study;
·
Monitor the performance of the
Project and the effectiveness of mitigation measures;
·
Take remedial action if
unexpected problems or unacceptable impacts arise; and
·
Provide data to enable an
environmental audit.
16.3.1
The EIA study has recommended a number of environmental control and
mitigation measures. The recommended EM&A programme will allow the
implementation and environmental performance of the environmental control/
mitigation measures to be checked.
16.3.2
Monitoring can be defined, in brief, as the systematic collection of
data through a series of repetitive measurements. It will involve the measurement of specified
environmental parameters before the commencement of the Project, and subsequent
impact monitoring during the operational phase of the Project. Environmental audit involves verification of
practice and certification of data. As
detailed in the EM&A Manual, the EM&A works shall be undertaken by a
project Environmental Team (ET) and audited by an Independent Checker
(Environment) (IC(E)).
16.3.3
The following areas, identified in the EIA for this Project, will
require EM&A during the construction or operational phase:
·
Air Quality: construction dust
·
Noise Impact: construction
noise
·
Water Quality
·
Waste Management
·
Ecology
·
Landscape and Visual
·
Cultural Heritage
Construction Dust Monitoring
16.4.1
Potential dust impacts could be
caused by the construction activities during the construction phase of this
Project. Dust mitigation measures with reference to the Air Pollution
Control (Construction Dust) Regulation have been highlighted in Section 4
of this report.
16.4.2
Furthermore, a construction
dust monitoring programme is recommended to carry out to ensure that dust
emissions generated from the Project are effectively mitigated to minimise the
associated impacts at nearby sensitive receivers.
16.4.3
Baseline monitoring should be
completed before the construction work commences. Impact monitoring should be
conducted whenever there is an ongoing construction work in the vicinity of the
proposed dust monitoring location. Event/ Action Plan should be triggered by
exceedance of action/ limit levels.
Regular site audits shall also be carried out by the ET and independent
audits carried out by the IC(E) to check for the implementation of the recommended
air quality mitigation measures.
16.4.4
Details of the monitoring and
audit requirements for construction dust are presented in the EM&A Manual.
Construction Noise Monitoring
16.5.1
Potential noise impacts could
be caused by the construction activities during the construction phase of this
Project. As noise mitigation measures have been proposed and formulated in the
EIA Study, EM&A is recommended to ensure that the mitigation measures are
timely implemented and that the noise sensitive receivers are protected
effectively by the proposed measures.
16.5.2
Baseline monitoring should be
completed before the construction work commences. Impact monitoring should be
conducted whenever there is an ongoing construction work in the vicinity of the
proposed noise monitoring location.
16.5.3
Details of the monitoring and
audit requirements for construction noise are presented in the EM&A Manual.
16.6.1
Water quality monitoring at the
relevant sensitive receivers near the Project during the construction phase is
recommended to ensure that the water quality is within acceptable levels and is
not significantly affected by the construction activities e.g. ponds dredging
and filling.
16.6.2
It is proposed to set up
upstream control stations and downstream impact monitoring stations to monitor
the water quality impact during the construction period. Release of sediment
particles and pollutants would be carried by the tidal flows downstream from
the Subject Site, the upstream monitoring station would not be affected by the
construction activities. However, the stations at the downstream location are
likely to be directly affected by the release of sediment particles and
pollutants from the site. This approach can minimise the influence from any
seasonal and local variations of water quality conditions in the region where
monitoring is carried out.
16.6.3
Upstream control and downstream
impact monitoring station are proposed to be set up at the upstream and down
stream of tidal river respectively.
16.6.4
Monitoring of effluents
discharging from the construction site is recommended during the construction
phase of the Project. The Contractor is responsible for application of a
discharge licence from EPD. The discharged effluents should be treated and the
effluent quality should comply with the licence conditions.
16.6.5
Details of the monitoring and
audit requirements for water quality are presented in the EM&A Manual.
Construction Waste Auditing
16.7.1
Auditing of each waste stream
is recommended to be carried out periodically to determine if wastes are being
managed in accordance with approved procedures and the Waste Management Plan
(WMP). The audits should cover all aspects of waste management including waste
generation, storage, recycling, treatment, transport, and disposal.
16.7.2
The general site inspections
including waste management issues is recommended to be undertaken weekly by
Environmental Team to check all construction activities for compliance with all
appropriate environmental protection and pollution control measures, including
those set up in the WMP. Meanwhile, waste management audit will be carried out
monthly basis by the Independent Environmental Checker (IEC).
16.8.1
Ecological monitoring is
recommended during construction and operational phase of the Project. The mitigation
measures should be included into contract clauses for construcion and operation
of the Projcet. The implementation of the measures should be audited as part of
the EM&A procedures during the construction and operational period. Details
of the monitoring programme, including the key limit and action levels and
their associated management actions are presented in Section 14-5 and the
EM&A Manual.
16.9.1
EM&A for landscape and
visual resources is proposed to be undertaken during both the construction and
operational phases of the Project.
16.9.2
The implementation and
maintenance of the landscape compensatory planting measures is a key aspect of
this and should be checked to ensure that the proposals are fully realised and
that potential conflicts between the proposed landscape measures and any other
project works and operational requirements are resolved at the earliest
possible date and without compromise to the intention of the mitigation
measures. In addition, implementation of the mitigation measures recommended by
the EIA will be monitored through the construction phase site audit programme.
16.9.3
Details of the monitoring and
audit requirements during the construction and operational phases are presented
in the EM&A Manual.
16.10.1
In order to retrieve
information concerning the composition of the bunds it is recommended that a
brief recording exercise with methodology agreed with the Antiquities and
Monuments Office be carried out during site formation.
16.11.1
An Implementation Schedule has
been prepared for the environmental mitigation measures recommended in the EIA
study in the form of a checklist. The
Implementation Schedule is as shown in Appendix 16-1.
17.
Summary
of environmental outcomes and overall conclusion
17.1.1 An Environmental Impact Assessment (EIA) has been conducted to
address all key environmental issues associated with the Project. The
assessments were carried out based on the requirements of the EIA Study Brief
(Brief No.: ESB-055/2000) issued by the Director of Environmental Protection
(DEP).
17.1.2 This section summarises and concludes the key environmental outcomes
associated with the Project in accordance with the requirement as specified in
Section 3.5.11 of the EIA Study Brief.
17.1.3 In respect of air quality impact, noise impacts, water quality
impacts, sewerage and sewage treatment implications, waste management
implications, fisheries impact and cultural heritage impact the impacts are
considered similar and acceptable for Preferred Options 1A and 1B However, in
respect of ecological impacts Option 1A is slightly superior to option 1B
whereas in respect of landscape and visual impacts Option 1B is considered
slightly superior to Option 1A. In general
terms though these differences are slight and the environmental impacts of both
Options 1A and 1B are found to be acceptable.
17.2.1 The key environmental issues studied in the EIA include air quality,
noise, water quality, potential problem of biogas, sewerage and sewage
treatment implications, waste, cultural heritage, landscape/ visual, fisheries
and ecological impact. Quantitative
assessments, and where appropriate semi-quantitative or qualitative assessments
have been carried out to assess the extent of potential impact. Mitigation measures have been recommended,
where necessary, to alleviate all identified environmental impacts associated
with the Project to acceptable levels. The conclusions for each of the assessed
environmental aspects are summarised below.
Construction Phase
17.3.1 The main concern for air pollution during the construction phase of
Development is fugitive dust (TSP) emissions associated with unloading of fill
materials from dump trucks for pond filling, vehicle movements on unpaved haul
roads, wind erosion on exposed ground and stockpiling areas, and handling of
excavated material and construction debris.
17.3.2
As the topsoil beneath the
ponds are of high moisture content and dredging works will be carried out at a
few fish ponds each time, dust emission is not considered a problem during pond
dredging at residential portion, and re-profiling of pond bunds, partial filling
of ponds during the establishment of WNR if mitigation measures are properly
implemented.
17.3.3
As the access road of the
Development will rely on existing Fuk
Shun Street, the limited site clearance works and
junction improvement works to widen the road will be constructed section by
section. The volumes of excavated spoil are expected to be low. The number of vehicle trips during
construction is expected to be very small and vehicle movements will be on
existing paved roadways. The construction works for access road is anticipated
to cause insignificant dust emission impacts when the construction mitigation
measures are implemented and through the Environmental Monitoring & Audit
programme.
17.3.4
As the sewers will be
constructed section by section and together with with the access road if the
alignment of the sewers follows the access road, the volumes of excavated spoil
are expected to be low. For the two sewerage options of the Project, the number
of vehicle trips during construction are both expected to be very small and for
most areas, vehicle movements will be on paved roadways. Only minimal movement of vehicles on unpaved
roads will be required.
17.3.5
Critical periods of fugitive
dust emissions will be during land formation for the marshland (Stage A) (i.e.
between 4th quarter of 2011 and 1st quarter of 2012) and site formation for the residential
portion of the Project when fill material have to be imported and handled for
ponds filling, spreading and compaction (Stage B) (i.e. between 2nd
quarter of 2012 and 4th quarter of 2012). For the prediction of the worst-case dust
impact, all the major activities in each of the 2 aforesaid scenarios have been
modelled in the EIA study and were assumed to be in concurrent operation.
17.3.6
Those existing village huts
scattered around the Project, mostly at the southern side of the Site, are
identified as Air Sensitive Receivers (ASRs).
17.3.7 With the implementation of a series of practicable dust control
measures such as frequent watering, enclosure of dust emission sources and
establishment and use of vehicle wheel and body washing station at exit points,
etc., a minimum dust control efficiency of 75% is achievable. The mitigated
results revealed that the dust levels would be within the hourly and daily TSP
limits of 500mg/m3 and 260mg/m3
respectively. Assuming that the dust generating activities are taking place
concurrently, the predicted highest hourly and daily average dust concentration
will be 256mg/m3
and 152mg/m3
at the identified ASRs respectively.
17.3.8 It is also an obligation of the Contractor(s) to comply with the Air Pollution Control (Construction Dust)
Regulation during the construction phase to mitigate dust emissions by use
of practicable measures as suggested in the EIA report.
17.3.9 Implementation of these measures can be enforced by incorporating as
contractual clauses. An Environmental Monitoring and Audit (EM&A) program
is also recommended to further check the implementation the dust mitigation
measures and compliance with the dust criteria.
17.3.10
As dredging works will be
carried out at only a few fish ponds each time and any exposed surface and
stockpiled material will be covered by impervious sheet or immediately filled
by filling materials during the construction phase, the potential odour nuisance
pose by the exposed pond sediment during dredging and pond filling is
considered to be minimal.
Operational Phase
17.3.11 There are no air and odour
emission sources within the Development, except potential odour nuisance from a
proposed pump house. However, with implementation of proper enclosure and
ventilation system to divert the odour emission to
odour scrubbing device (e.g. enclosed concrete structure and activated carbon
filter at the air vent of the pump house), no insurmountable odour impact is
anticipated. Further discussions are presented in Section 8.8.6.
17.3.12 A minimum setback distance of 125m is provided between the closest
existing local distributor Fuk
Shun Street and the proposed development. Referring to the Hong Kong Planning Standard
and Guidelines (HKPSG), a buffer distance of not less than 5m shall be provided
between a local distributor and an open space site for active and passive
recreational uses. In this regard,
sufficient buffer distance will be provided and the buffer requirements as
recommended in the HKPSG could be met. The operational air quality impact
arising from the vehicular emission is considered insignificant.
17.3.13 Given the remoteness of the
chimneys located in the YLIE and the YLSTW from the Development (about 400m and
500m away from the Subject Site respectively), the operational
air quality impact arising from the chimney emissions from the YLIE and the
odour from the YLSTW are also considered to be insignificant.”
Construction Phase
17.4.1
Construction
works of the Project could be a cause for construction noise impact on nearby
noise sensitive receivers. Hence the potential cumulative noise impacts of the construction of the
access road, the residential portion and the WNR have been assessed in accordance with general acoustic principles and
guidelines given in Para. 5.3 and 5.4, Annex
13 of the EIAO TM.
17.4.2 Construction noise is controlled under the Noise Control Ordinance
(NCO), which prohibits the use of powered mechanical equipment (PME) during the
restricted hours (7 p.m. to 7 a.m. on normal weekdays and any time on a public
holiday, including Sunday) without a valid Construction Noise Permit (CNP)
granted by the Authority.
17.4.3
Percussive piling is controlled
similarly by a noise permit system and described in the NCO and the “Technical
Memorandum On Noise From Percussive Piling” (TM3) which restrict the number of
hours during which piling can be conducted.
No percussive piling may be carried out in the territory without a valid
CNP issued by the Authority. Besides, a
CNP will only be granted for percussive piling, which is scheduled during
normal working hours between 7 a.m. to 7 p.m. from Monday to Saturday.
17.4.4 The future Contractor undertaking the construction work will be
subject to this statutory requirement and hence the impact was not predicted in
this restricted period. Rather, the impact during the non-restricted periods
(i.e. between 07:00 to 19:00 on Monday to Saturday) has been the focus of the
assessment.
17.4.5 Based on a tentative construction programme and a reasonably
developed set of equipment inventory, cumulative construction noise impacts
have been conservatively predicted.
17.4.6 Results indicated that the unmitigated cumulative noise impact could
exceed the relevant noise limit of Leq(30min.) 75 dB(A) by 3 - 15
dB(A) at sensitive receivers situated in close proximity to the site. In view
of this, a series of progressive mitigation measures have been recommended to
alleviate the impact. These include: -
·
Use of quiet/silenced equipment
and working method;
·
Use of temporary noise barriers
and machinery enclosures;
·
Good site practice and noise
management, etc.
17.4.7 A further prediction based on the assumption of use of these
mitigation measures has revealed that the noise impact could be mitigated to
acceptable levels at all sensitive receivers. Required noise mitigation
measures can be incorporated as contractual obligations for the contractor in
carrying the works. An EM&A programme has also been recommended for
checking the implementation of the recommended noise control measures and
compliance with the statutory noise criteria.
Operational Phase
17.4.8
Sewage pump house at the
residential portion of the Project is the only major noise source identified to
be of concern to the future noise sensitive receivers. Based on conservative
assumptions of the possible noise power levels for the sewage pump house, the
noise impact was evaluated and has been found to be acceptable if a minimum
setback of 15m (or less for smaller pumps) is observed. The pumps should be
housed inside a concrete structure with openings facing away from any NSRs.
17.4.9
Subject to the selected
sewerage option and the final design of the MLP and the pump house, the
sewerage pump house is tentatively proposed to be housed inside a concrete
structure near the car-park area for the visitors with openings at the southern
side facing away from any NSRs. As such, the pump house will have a setback
distance of more than 150m from the residential block and nearby NSRs.
17.5.1 The assessment has been conducted in accordance with the
requirements given in Clause 3.5.2 of the EIA Study Brief. The criteria and guidelines as presented in
Annexes 6 and 14 of the EIAO TM have been adhered to in the study.
Construction Phase
17.5.2
The establishment of the WNR
will involve creation of marshland and re-profiling and landscaping of the
ponds.
17.5.3
The construction of the
residential portion of the Project requires ponds draining, dredging and
filling at 6 fish ponds at the southern boundary of the site.
17.5.4 The key concern in water pollution during the construction phase of
the project relates to the possible discharge of surface runoff contaminated by
suspended solids released as a result of the site formation and pond filling
works. Control in water pollution shall be achieved though implementation of
the Best Management Practices (BMPs) to avoid contact of pollutants with
rainfall or runoff and measures to abate pollutants in the stormwater
runoff. The guidelines for handling and
disposal of construction site discharges as detailed in EPD’s ProPECC Note
PN1/94 “Construction Site Drainage” should be followed. Mitigation clauses targeted to minimise water
pollution arising from construction site runoff, construction site wastewater,
oils and solvents etc. are recommended for implementation through inclusion as
contract clauses.
17.5.5
Through transferring the pond
water within the subject site, the need of discharging pond water into the
surrounding water bodies during the construction of the Project can be avoided.
Operational Phase
17.5.6 Water for use in the WNR will be provided by direct rainfall supplemented
by run-off from the residential development and catchments A and B via a ditch
running along the southern border of the development area. Water will drain
into the storage pond at the eastern end of the proposed WNR.
17.5.7 The run-off from residential site will pass through traps to remove
oil and grease, and sand and gravel filters to reduce silt loads and
particulate organic matter prior to discharge into the ditch and the storage
pond. As runoff water from the catchments and development area will be stored
for long periods before entering the wetland area any remaining silt that is
present will be able to settle out in the water. This will further
significantly reduce pollutant levels (from the residential runoff and
catchments A and B). Regular maintenance, e.g. periodic de-silting will be
required. It is believed that the quality of the water discharge will be better
than that of the baseline situation as well as the upstream water quality.
17.5.8
Foul water, on the other hand,
will be discharged to the public sewer.
17.5.9
The water levels of the
fishponds inside the wetland nature reserve will be managed and controlled by
the conservation manager. During normal operation, the wetland nature reserve
will be self-contained and pond water will not be discharged to the
surrounding. Water will only be discharged when there is overflow.
17.5.10
The fishponds comprising the
WNR will be interconnected with adjustable sluices to allow the circulation of
water to reduce the likelihood of overflow upon heavy storm. In wet season,
though unlikely, excess water will be drained and discharged to the Tai River
under the management of conservation manager.
17.6.1 As the residential footprint is planned to build on the existing
fishpond area, under anaerobic conditions, the pond mud left in-situ can
generate potential biogas risk.
17.6.2 With the TOC and SOD contents of the pond mud in-situ
sampled, the potential methane flux from the Development based on half-lives of
5 is estimated. Even under the extreme worse case scenario (100% of TOC is
biodegradable), the results are well below with the guide value stipulated in
EPD’s Landfill Gas Hazard Guidance Note and the maximum “safe” rate of gas
emission derived from the Department of the Environment (1993), Landfill
Completion. Waste Management Paper No. 26A.
17.6.3 Generic gas precautionary measures for the below ground structures
of Development and precaution measures to be taken prior to entry into any
below ground services or confined space within the Development are recommended.
17.6.4 With the incorporation and implementation of the recommended
precautionary measures, the potential biogas hazard posed to the Development is
considered to be minimal.
17.7.1 With reference to the recommendation and projection in the Review of
Yuen Long and Kam Tin Sewerage and Sewage Treatment Requirements and taking
into consideration the existing and committed sewerage facilities in the
vicinity of the proposed Development, the 2 sewage disposal strategies for the
Project have been investigated:
Strategy A (Eastern Option) – provide a new sewer to discharge sewage to YLSTW via local roads
e.g. Fuk Shun Street.
Strategy B (Western Option) – provide a new sewer to discharge
sewage to the proposed Tin Shui Wai Pumping Station at Area 101 via Tin Wah Road. The
sewage at TSW Pumping Station passes through Ha Tsuen Pumping Station and
eventually transfers the flow to San Wai STW.
17.7.2 The 2 proposed strategies are all considered technically feasible
although they will be subject to negotiation and agreement with the relevant
Government department.
17.7.3 Two alternative alignments are proposed for Strategy A. For Strategy
A1, new sewers connecting between the new pump house on-site and YLSTW are
proposed to be built. No upgrading works of sewers are required for this
sewerage option. A new sewer will be laid beneath existing local road, Fuk Shun Street and
the local next to Leon Court.
Strategy A2 is to build a new sewer connecting to existing sewer (through
manhole HK19369006) under Fuk Shun
Street. As supported by the SIA presented in
Appendix 8-1, no upgrading works on existing sewers are considered necessary.
17.7.4 For Strategy A, YLSTW will have adequate spare capacity to cope with
the estimated additional resentitial sewage from the FLW Project. Feasibility for Strategy A1 and Strategy A2
has been studied in the SIA as presented in Appendix 8-1.
17.7.5 Strategy B involves laying an approximate 940m new sewer beneath
planned/existing carriageway at the western side of the subject site. Wayleave
from the Government is required. The Sewerage Impact Assessment conducted has
found that upgrading of the existing sewage pipes with length of 948.8m at Tin Wah Road is
considered necessary to convey the flow from the FLW Development to TSW pumping
station.
17.7.6 In broad terms, these strategies involve installing an on-site
sewage pump house within the Development and providing a new sewer to discharge
sewage to the nearby sewage treatment work or pumping stations.
17.7.7 Subject to the selected sewerage option and the final design of the
MLP and the pump house, the sewerage pump house is tentatively proposed to be
housed inside a concrete structure near the car-park area for the visitors with
openings at the southern side facing away from any Noise Sensitive Receivers.
It will be equipped with 2 duty and 1 standby sewage pump to raise the sewage
head by about 9m. Given its proven reliability and ease of inspection and
maintenance, electrically operated vertical spindle non-clog dry well sewage
pump will be used and the total designed capacity of the pump house is 182 l/s.
The feasible discharge point of overflow bypass is either through Tai River to
the West or Shan Pui River
to the East.
17.7.8 The selection of sewerage options remains open at this stage.
Strategy A is preferred option, however, it will be subject to the spare
capacity of YLSTW and the completion program for the Yuen Long Effluent
Pipeline.
17.8.1 The waste streams that will be generated during the construction and
operational phase of the proposed Project at Fung Lok Wai are identified and
evaluated in terms of their nature, type, quality, quantity, and associated
environmental impacts. Opportunities for reduction in waste generation through
recovery, reuse or recycling are identified.
17.8.2 The waste management implications and potential environmental
impacts associated with the handling, transport, and disposal of the identified
waste types are evaluated and addressed.
An EM&A programme is recommended to be in place during the construction
phase to check the waste generated from the construction site are being managed
in the accordance with the recommended procedures.
17.8.3 With the recommendations implemented, no waste related regulatory
non-compliance and unacceptable environmental impacts are expected to arise
from the handling, storage, transport and disposal of construction waste
arising from the proposed residential and wetland nature reserve development.
17.8.4 The nature of the historical uses of the site and the findings of
the sediment sampling results confirm that land contamination should not be a
concern.
17.9.1 This assessment was conducted in accordance with the requirements
given in section 3.5.6 of the EIA study brief. All ecological impacts have been
assessed according to criteria outlined in annexes 8 and 16 of the EIAO
Technical Memorandum.
Evaluation of impacts
Habitat loss
17.9.2 The proposed development at Fung Lok Wai will result in no permanent
habitat loss to ecologically valuable habitats in the WCA. The actual operation
phase footprint (i.e. land directly and permanently lost by the project) will
be approximately 4.0 hectares (primarily aquaculture ponds and a very small
area of drainage ditch. This change in habitat use will occur as a result of
the land used for the construction of residential blocks, associated structures
and access roads and storage areas for materials and equipment etc. However the
loss of water body is compensated by re-profiling the ponds in the Wetland
Nature Reserve (WNR) area. This creates ecologically enhanced and enlarged
ponds, and recreated marshland habitat. Consequently there is no net loss of
water body area or ecological function. No additional habitat loss is
anticipated as a result of the construction of either sewerage strategy or the
preferred (southern) access route.
17.9.3 An integral component of the proposal is the development of a WNR on
the remaining 76.1 hectares of the site. The creation of the WNR will involve
the transformation of approximately 14.4 hectares of aquaculture ponds to
freshwater marsh and the enhancement (through enlargement) of 61.7 hectares of
aquaculture ponds. Whilst intended to compensate for impacts arising from the
construction of the residential component of the development and, therefore,
expected to have overall positive benefit, the WNR works will involve permanent
and temporary habitat loss of aquaculture ponds (fishponds that are actively
managed, those that are currently unmanaged, and the intervening bunds) and
ditches and drainage channels.
17.9.4 The major potential species impacts associated with the proposed
development relate to:
·
Disturbance caused by the
construction and operation of the proposed development, including the WNR; and,
·
Fragmentation – in particular
the obstruction of flightlines of birds moving to and from the Shing Uk Tsuen
egretry (now abandoned).
Disturbance
17.9.5 Species most likely to be affected by disturbance impacts are birds,
particularly flock feeding waterbirds, larger herons and birds of prey, and
mammals, particularly larger species. Such species are likely to be disturbed
by loud noises, moving objects and the presence of people. Stationery objects
such as buildings, are also sources of disturbance as these may obscure flight
lines and views of potentially approaching predators. As no large mammal
Species of Conservation Importance were recorded during the field surveys,
particular attention is therefore focused on assessing the impacts of disturbance
on bird Species of Conservation Importance recorded at the site.
17.9.6 An assessment of the predicted impacts of disturbance on each
Species of Conservation Importance that regular occurs in significant numbers
has been carried out. The assessment is
based on a combination of literature review, analysis of field survey data and
experience of the study team and previously accepted assessment criteria.
Disturbance impacts have been calculated by defining distance from the edge of
the disturbance source to the furthest point of:
·
An avoidance zone –Where a particular species is precluded from using
the area; and
·
A zone of reduced density – Where the numbers of a species are lower
than they would be in the absence of disturbance either because it occurs in
lower numbers (more tolerant individuals) and/or for a shorter period of time
(for example during periods of reduced human activity). In this analysis, it is
assumed that the overall utilisation of the zone of reduced density is 50% of
that in undisturbed areas (0% utilisation at the border with the avoidance zone
rising to 100% utilisation at the border with the undisturbed areas).
17.9.7 These distances have been estimated for construction and operation
phase impacts and for disturbance impacts, particularly within the fishpond
area and proposed freshwater marsh, which are considered to be of greatest
value to the identified Species of Conservation Importance. The predicted
disturbance impacts have been calculated on the assumption that there will be
low-level visual human disturbance and that basic mitigation measures,
including the creation of wetland habitats with reedbeds and the planting of
trees and bamboo, as screening will be implemented.
Fragmentation – flight line obstruction
17.9.8 Comparison of alternative development options indicated that it was
possible to reduce the potential impact of the residential development on
flightlines associated with the egrety existed at the time of survey (now abandoned) by
shifting the Development Area eastwards. In anticipation of potential impacts
of the development on flightline activity and to mitigate for these impacts the
Proposed Development Area was moved eastwards by about 150m to increase
distance from the egretry location, leading to a reduction in flightline
intersection. In addition to this, further mitigation is proposed in the form
of the creation of a potential alternative egretry site.
17.9.9 Although the ecological effects of Options 1A and 1B are considered
to be similar in most respects, it is predicted that Option 1B will result in
slightly greater habitat fragmentation than Option 1A. The larger number of
buildings in Option 1B is expected to restrict the sightlines of birds to a
slightly higher degree than would be the case in Option 1A. The difference is,
however, slight, particular in light of the abandonment of the egretry which
will result in reduced levels of flight activity.
Habitat Compensation
17.9.10 The aim of habitat compensation will be to replace habitats of intrinsic ecological value that will be lost or degraded. Compensation
may be carried out through replacement of important habitats to be lost or the
enhancement of existing habitats (i.e. by raising the ecological value of the
habitat and thereby its carrying capacity for target species).
Compensation for Direct Habitat Loss
17.9.11 No net loss of water body will be ensured through the removal
of terrestrial bund habitats of low ecological value and replacement with
further wetland area and shallow incorporated into to the design of the WNR. It
is predicted that pond enlargement and marsh habitat creation will result in
the removal of approximately 4.4 ha of pond bund which will more than
compensate for the area of fishpond lost under the development footprint.
Compensation for Functional Habitat Loss
17.9.12 Calculations of the overall land requirements to compensate for
disturbance effects for species considered to be most sensitive to disturbance
impacts have been derived within the EcIA. If the requirement to compensate for
the disturbance to these species is met, full compensation for the impacts of
direct habitat loss and disturbance to less-sensitive species Species of
Conservation Importance is likely to be achieved, as long as appropriate
habitat is provided. Mitigation for other impacts on both birds and other
Species of Conservation Importance are addressed later in this section.
17.9.13 The level of functional improvement of remaining wetland habitat is
calculated by quantifying the area of the proposed development, plus the
wetland area lost within the disturbance exclusion zone for each species, plus
the wetland area lost through reduced density disturbance. This
total is divided by the area of undisturbed wetland habitat remaining, to
obtain the functional improvement factor.
Objectives of the Wetland Nature Reserve
17.9.14 The WNR will be established on the remaining 95% (approximately 76.1
ha.) of the site unaffected by the residential development.
17.9.15 The goal of the WNR is to provide compensation for loss of habitat
and disturbance associated with the construction and operation of the
residential development. The result will be no net loss of either function of
wetland habitat or area of water body.
17.9.16 No net loss of water body area will be achieved through
reconfiguration of fish ponds to create fewer, larger ponds and the creation of
a complex of freshwater marsh habitats. Increasing fish pond size has an
additional benefit as there is evidence that many wetland birds prefer larger,
less enclosed waterbodies to the small ponds which typify most aquaculture
practices. The removal of some bunds is predicted to have low or negligible
impact as their intrinsic ecological value is low. The complex of freshwater marsh
habitats proposed will provide a range of additional habitats for birds and
other flora and fauna, including dragonflies.
17.9.17 Functional enhancement will be achieved through enhancement of both
the ponds and the approach to aquaculture management. The carrying capacity of
fishponds is limited by the uniform design of ponds and management that is not
specifically targeted at conservation. Modifications to both will significantly
improve foraging opportunities for birds and other fauna. To ensure ongoing functional
replacement, key ecological indicators, including birds, will be monitored to
guide management of the reserve.
17.9.18 Detailed design principles of the WNR are provided within the EcIA
and WNR construction works will be staged to minimise the disturbance of the
site.
17.9.19 Responsibility for the management of the WNR rests with the project
proponent who will be responsible for the proper management and operation of
the WNR until a designated successor such as an independent Foundation is
identified to the satisfaction of EPD or its agents.. Subject to the necessary
agreements from relevant government authorities, an independent, non-profit
Foundation will be established to take over the long-term management of the
WNR. Similar in form to a Conservation Trust, the Foundation will provide
guidance and resources on strategic and day-to-day management of the reserve.
17.10.1 This assessment is prepared in accordance with the requirements of
the EIAO and the criteria and guidelines defined in Annex 9 and 17 of the EIAO
TM.
17.10.2 The Project involves the
construction of the Wetland Nature Reserve comprising enhanced and enlarged
fishponds, rain fed ponds for water birds and a complex of freshwater
marshlands and the construction of residential development. The design
principles of no net loss of area and functional enhancement of wetland
habitats are to be achieved through the reconfiguration of pond bunds to create
larger and functionally enhanced ponds which are more preferred by birds and to
create land for residential development. Through the pond bunds
reconfiguration, there will be a slight increase in the area of water body
within the Site. As the WNR is designated for more diversified ecology and only
a portion of the WNR is proposed as fishpond habitat, there will be a loss of
fishponds for fish production (permanent loss of 20.8
ha of active commercial fishponds and approximately 5.4 ha of inactive ponds). Those
ponds that remain, however, will be enhanced to increase their ecological
values, primarily for bird Species of Conservation Importance. They will,
however, continue to be managed in largely traditional manner within which fish
production will still be a key objective. The establishment of the Wetland
Nature Reserve will ensure that this enhanced management regime is implemented
in the long term. In this respect the fish production and fishponds will be
more sustainable than comparable ponds elsewhere within Deep Bay.
17.10.3 The long-term management of these ponds ensures the preservation of
the cultural practice of aquaculture in-situ, which is consistent with concepts
of “wise use” fore-shadowed in Article 3.1 of the Ramsar Convention. It also
provides opportunities for ongoing research into sustainable fish production
and wildlife conservation.
17.10.4
Off-site impacts are not
anticipated as the likelihood of adverse impacts on water quality of
neighbouring ponds, estuarine and marine receiving environments is considered
to be very low during either construction or operation phases.
17.11.1 The cultural heritage impact of the Project are evaluated and assessed
in accordance with the requirements stated in Clause 3.5.8 of the Study Brief
and the criteria and guidelines stated in Section 2 of both Annexes 10 and 19
of the TM.
17.11.2 The findings and recommendations of the Cultural Heritage Impact
Assessment include:
Historical Buildings and Structures Survey
Findings and Assessment
·
There were no cultural heritage
resources located in the Study Area. All structures were identified as modern
squatter structures with no cultural heritage features
·
The three villages highlighted
in the study brief were found to contain 112 cultural heritage resources
·
A number of graves were
identified on the hill behind the village
of Ng Uk Tsuen (outside
of the Study Area)
·
A fung shui wood was identified
behind the village
of Ng Uk Tsuen (outside
of the Study Area)
Recommendations
·
The Study Area contained no
cultural heritage resources, thus, no mitigation measures are required
·
The cultural heritage resources
outside the Study Area were found to warrant no further mitigation measures
based on the following factors:
o
Adequate screening from the
development site through existing woodlands, topographical setting and modern
structures
o
Sufficient distance from the
development site
o
Orientation away from the
development site
Historical Landscape Features
Findings and Assessment
17.11.3 The assessment has found that although the basic pattern of the
bunds was retained, the bunds have been extensively changed in size and shape.
Recommendations
17.11.4 In order to retrieve information concerning the composition of the
bunds it is recommended that a brief recording exercise be carried out during
site formation.
17.12.1 The potential impacts to the landscape resources and character, and
visually sensitive receivers arising from the proposed development has been
assessed in accordance with Clause 3.5.9 of the EIA Study Brief, Annexes 10 and 18 of the EIAO –
TM. The methodology stated in Section 11.3 for undertaking the landscape and
visual impact assessment follows the provisions of EIAO Guidance Note No.8/2002
- Preparation of Landscape and Visual Impact Assessment under the EIAO. During
the selection of the preferred option it was found that two options, 1A and 1B, were equally acceptable from a landscape
and visual impact perspective, and so both options were taken forward in to the
detailed assessment. The findings and conclusions from this dual assessment are
described below.
Landscape Planning and Development Control Review
17.12.2 A review of the future proposals for the Study Area as represented
in the Outline Zoning Plans reveals that the proposed schemes for both Options 1A and 1B will fit into the future landscape
of the Study Area. Further the proposed marsh habitat planned for the area to
the north of the development site will form a continuation of the existing Hong Kong Wetland Park
contributing to a more coherent landscape framework. The proposals would
therefore largely be compatible with the planning intention for the area and
the planned landuses in the adjoining areas.
Existing Trees – Options 1A
and 1B
17.12.3 Generally trees or tree groups will be maintained where
possible. It is estimated that
approximately 238 (36%) of the trees would be retained. The proposed compensatory planting of a combination
of native and amenity tree species will mitigate the potential impacts on the
existing trees within the development site. This includes the planting of some
300 new trees within the main development area in addition to the 3750 square
metres of mass woodland planting established within the project boundary. This
equates to some 1050 new trees with a compensatory planting ratio of
approximately 2.6:1 (new planting: trees recommended for felling).
Landscape Resources – Options 1A and 1B
17.12.4
In general the impact on LRs
within the Study Area will be largely negligible. Further many will generally
benefit from by the creation of WNR and fishpond enhancement as these works
would improve the quality of the resource including their ecological value. This
enhancement includes the establishment of plantation woodland with a moderate
beneficial impact. The main impacts on the landscape resources of the area are
due to the loss of approximately 4 hectares of fishponds (LR 8) and a lesser
extent the loss or modification of the existing landform (LR 1) due to the
proposed creation of the WNR which will result from the removal of some
fishpond bunds. Despite these losses being relatively small compared to the
overall area of the resource the fish ponds are important to the landscape area
of the region and so this has informed the design of the proposals leaving the
largest possible area intact. The impacts to these resources will range from
moderate to slight adverse with the impact on the other landscape resources
within the Study Area being largely negligible.
Landscape Character – Options 1A
and 1B
17.12.5
The growth to maturity of the
tree and shrub planting proposed as part of the marsh habitat and the landscape
buffer planting on the periphery of the development will serve to encourage a
greater sense of landscape and visual integration with the development’s
context. This planting will also serve to soften the transition between the
verticality of the proposed built environment and the surrounding coastal plain.
The planting proposals will also alleviate some indirect impacts on the Ng Uk
Tsuen Village Cluster (V1) and the Kai
Shan Range
(NUA 1) and benefit the local character ranging from slight to moderate adverse
impact with full establishment of the proposed mitigation measures. The impact
on the landscape character of the village cluster will be restricted to the
northern periphery of the settlement. Impacts on the character of the existing
Fishponds (AGR 2) will also be partially alleviated through the implementation
of the proposed mitigation measures resulting in a moderate adverse impact. The
landscaping associated with the proposed landscape buffer and the establishment
of the WNR would also have a slight beneficial impact on the adjacent areas of
the Hong Kong Wetland Park (OS1).
Visual Amenity – Options 1A
and 1B
17.12.6
Many of the views for the
identified VSRs share a number of common characteristics which include their
expansive nature, the viewing distance and in many cases an elevated viewing
position resulting in slight to moderate/significant adverse impact. In this
situation the proposed primary mitigation measures such as the location of the
development platform and form of the built structure including the adoption of
a stepped building height, incorporation of sky gardens (Option 1A) and view
corridors take precedence over the proposed soft landscape mitigation measures
although these measures serve an important role in further mitigating the
predicted adverse impacts.
17.12.7
The shared characteristics of
the existing views mean that for many VSRs Options 1A and 1B would appear
similar. It may be argued that despite the Option 1B adopting a 15 storey
maximum height the flat roofline (contrasting with the organic forms of the adjacent
landscape), the introduction of an additional block, the omission of sky
gardens and the reduced view corridors ensure that the proposals have a similar
level of visual prominence. Given this the predicted visual impacts particular
for the VSRs to the north, east and west of the application site are similar to
those predicted for Option 1A.
17.12.8
The main differences between
Options 1A and 1B would be
apparent in views from within the villages of Ng Uk Tsuen (VSR 6) and Shing Uk
Tsuen (VSR7). The reduced height of Option 1B would reduce the visibility of
the proposals in views from within the village however in many instances these
views are largely interrupted by existing features such as the adjacent village
houses and the intervening vegetation. In views from the northern periphery of
the village it is considered that the reduced height of Option 1B is balanced
to an extent by the wider view corridors of Option 1A which allow greater albeit framed visual access to
the fishpond area to the north. The predicted visual impacts for Options 1A and 1B when viewed from the edge of
the villages (approximately 10 houses would be affected) would be significant
to moderate advesre although these impacts would affect a relatively small
number of VSRs. Whilst the predicted visual impacts for VSRs with a view of the
proposals for Option 1A would
be slight to moderate adverse and Option 1B slight adverse. Again due to the
characteristics of the existing views from within the villages these impacts
are limited to a relatively few VSRs.
Potential Night Time
Glare – Options 1A and
1B
17.12.9
Given that the majority of the
identified VSRs are located at distances of 1000m or more from the proposed development and the
fact that in many views the development will be seen against the backdrop of
the existing street lighting in the adjacent villages and Yuen Long the
predicted night time glare impacts will not be significant. The adoption of
responsive lighting design with glare control measures would serve to mitigate
much of the potential impacts. In addition the proposed use of a vegetative
landscape buffer and the screening effect of the existing vegetation will
mitigate much of the potential night time impacts for VSRs at low elevations
such as the Hong Kong
Wetland Park.
Overall the night-time glare impact resulting from the proposed architectural
and road lighting would have a predicted slight adverse to negligible impact
for the large part of the existing and planned VSRs.
Acceptability of Impacts
17.12.10
In
accordance with Annex 10, Paragraph 1.1(c) of the EIAO TM, the landscape and
visual impacts of the project under the proposed
development at Fung Lok Wai for both Options 1A and 1B would be ‘acceptable with mitigation’ that
is to say `there would
be some adverse effects, but these can be eliminated, reduced or offset to an
extent by specific measures’..
17.13.1 All key environmental issues related to the construction and
operation of the Project are identified and assessed in accordance with the
requirements of the EIA Study Brief. Practicable and cost-effective mitigation
measures have been recommended where necessary to minimise the identified
impacts to acceptable levels. An EM&A programme is also recommended for
checking the implementation of sufficient mitigation measures with respect to
key environmental concerns identified for the construction phase.
17.13.2 In conclusion, with the implementation of the recommended
environmental mitigation measures, the construction and operation of Project in
the form of either Option 1A or Option 1B should not cause any unacceptable
environmental impact on the surrounding sensitive uses.