Proposed Comprehensive Development

at Wo Shang Wai, Yuen Long

 

Environmental Impact Assessment

 

 

March 2008

 

 

 

Mott Connell Ltd

7th Floor, West Wing Office Building

New World Centre

20 Salisbury Road

Tsim Sha Tsui, Kowloon

Hong Kong

 

Tel: 2828 5757

 

Fax: 2827 1823

 

Anne.Kerr@mottconnell.com.hk

in association with

 

Urbis Limited

Master Plan Limited

Asia Ecological Consultants Limited

Allied Environmental Consultant Limited

 

"This document has been prepared for the titled project or named part thereof and should not be relied upon or used for any other project without an independent check being carried out as to its suitability and prior written authority of Mott Connell being obtained. Mott Connell accepts no responsibility or liability for the consequences of this document being used for a purpose other than the purposes for which it was commissioned. Any person using or relying on the document for such other purpose agrees, and will by such use or reliance be taken to confirm his agreement, to indemnify Mott Connell for all loss or damage resulting therefrom. Mott Connell accepts no responsibility or liability for this document to any party other than the person by whom it was commissioned.

 

To the extent that this document is based on information supplied by other parties, Mott Connell accepts no liability for any loss or damage suffered by the client, whether contractual or tortious, stemming from any conclusions based on data supplied by parties other than Mott Connell and used by Mott Connell in preparing this document."

 

 


List of Contents Page

Chapters                                                                                                                            Page No.

1        INTRODUCTION   1-1

1.1      Background  1-1

1.2      The Project 1-2

1.3      EIAO and Designated Projects  1-5

1.4      Continuous Public Involvement 1-5

1.5      Scope  1-6

1.6      Objectives of the EIA Study  1-6

1.7      The Assessment Area  1-7

1.8      Programme  1-8

1.9      Structure of the EIA Report 1-8

2        CONSIDERATION OF ALTERNATIVES   2-1

2.1      Summary  2-1

2.2      The Project Area  2-1

2.3      Site Context 2-5

2.4      Consideration of Alternatives  2-6

2.5      Working Up the Initial Options  2-13

2.6      Construction Methods and Sequences of Works  2-19

3        Air Quality   3-1

3.1      Summary  3-1

3.2      Legislation, Standards, Guidelines and Criteria  3-2

3.3      Assessment Methodology  3-3

3.4      Baseline Conditions/ Sensitive Receivers  3-4

3.5      Air Quality Impact Assessment 3-5

3.6      Mitigation of Impacts  3-8

3.7      Residual Impacts  3-9

3.8      Environmental Monitoring and Audit 3-10

3.9      Conclusions and Recommendations  3-10

4        NOISE IMPACT   4-1

4.1      Introduction  4-1

4.2      Government Legislation and Standards  4-1

4.3      Background Noise Climate  4-3

4.4      Identification of Potential Noise Impacts  4-5

4.5      Determination of Noise Sensitive Receivers  4-6

4.6      Assessment Methodology  4-8

4.7      Prediction and Evaluation of Noise Impacts  4-12

4.8      Mitigation Measures  4-14

4.9      Conclusion  4-18

5        WATER QUALITY IMPACT   5-1

5.1      Summary  5-1

5.2      Environmental Legislation, Standards, Guidelines and Criteria  5-1

5.3      Existing Environment and Sensitive Receivers  5-5

5.4      Assessment Methodology  5-14

5.5      Identification of Impacts  5-14

5.6      Mitigation Measures  5-17

5.7      Environmental Monitoring and Audit 5-18

5.8      Conclusions  5-19

5.9      References  5-19

6        Sewerage and Sewage Treatment Implications   6-1

6.1      Summary  6-1

6.2      Introduction  6-1

6.3      Assessment Approach and Methodology  6-1

6.4      Design Assumptions, Parameters and Criteria  6-2

6.5      Existing Sewerage Conditions  6-3

6.6      Estimated Pollutant Loads to the Existing Water Body due to the Proposed Development 6-4

6.7      Proposed Mitigation Measures  6-5

6.8      Short Term Measures during Construction Stage  6-6

6.9      Conclusion and Recommendations  6-6

7        WASTE MANAGEMENT   7-1

7.1      Summary  7-1

7.2      Environmental Legislation and Standards  7-1

7.3      Assessment Methodology  7-2

7.4      Construction Waste Impact 7-2

7.5      Evaluation of Impacts  7-4

7.6      Mitigation Measures  7-6

7.7      Land Contamination  7-9

7.8      Sediment Quality and Potential Biogas  7-22

7.9      Environmental Monitoring and Audit Requirements  7-40

7.10    Conclusions  7-40

8        Ecological Impact assessment   8-1

8.1      Summary  8-1

8.2      Introduction  8-1

8.3      Assessment Area  8-2

8.4      Sites of Conservation Importance in the Area  8-3

8.5      Survey Methodologies  8-4

8.6      Results of surveys  8-8

8.7      Ecological Value of habitats in the Project Area and within the Assessment Area  8-27

8.8      Potential Ecological Impacts  8-38

8.9      Mitigation Measures Adopted to Avoid, Minimise and Compensate for Ecological Impacts  8-54

8.10    Post-mitigation Acceptability of the Project 8-65

8.11    Conclusions  8-72

8.12    References  8-73

9        Fisheries Impacts ASSESSMENT   9-1

9.1      Summary  9-1

9.2      Legislation and Standards  9-1

9.3      Assessment Methodology  9-2

9.4      Baseline Conditions  9-2

9.5      Prediction of Impacts  9-4

9.6      Evaluation of Impacts  9-6

9.7      Mitigation Measures  9-7

9.8      Environmental Monitoring and Audit Programme  9-8

9.9      Conclusion  9-8

9.10    References  9-8

10      CULTURAL HERITAGE  10-1

10.1    Summary  10-1

10.2    Relevant Legislation & Guidelines  10-1

10.3    Assessment Methodology  10-2

10.4    Baseline Conditions and Sensitive Receivers  10-2

10.5    Impact Assessment 10-3

10.6    Mitigation Measures  10-4

10.7    Residual Impacts  10-4

10.8    Conclusion  10-4

10.9    Reference  10-4

11      Landscape and Visual Impact   11-1

11.1    Summary  11-1

11.2    Environmental Legislation and Guidelines  11-2

11.3    Scope and Content of the Study  11-3

11.4    Planning and Development Control Framework  11-7

11.5    Baseline Study  11-9

11.6    Landscape Impact Assessment 11-21

11.7    Visual Impact Assessment 11-43

11.8    Conclusions  11-58

12      IMPACTS SUMMARY   12-1

12.1    Summary  12-1

13      SUMMARY OF ENVIRONMENTAL OUTCOMES   13-1

13.1    Overall 13-1

13.2    Air Quality  13-1

13.3    Noise  13-1

13.4    Water Quality  13-1

13.5    Sewerage and Sewage Treatment 13-2

13.6    Waste Management 13-2

13.7    Ecology  13-2

13.8    Fisheries  13-2

13.9    Cultural Heritage  13-2

13.10   Landscape and Visual Impact 13-2

14      ENVIRONMENTAL MONITORING AND AUDIT (EM&A) REQUIREMENTS   14-1

14.1    Overview   14-1

14.2    Air Quality  14-1

14.3    Noise Impact 14-1

14.4    Water Quality  14-1

14.5    Sewerage and Sewage Treatment Implications  14-2

14.6    Waste Management 14-2

14.7    Ecology  14-2

14.8    Fisheries  14-2

14.9    Cultural Heritage  14-2

14.10   Landscape and Visual Impact 14-2

15      PROJECT IMPLEMENTATION SCHEDULE  15-1

16      SUMMARY AND CONCLUSIONS   16-1

16.1    Summary  16-1

16.2    Conclusions  16-1

 

List of Tables

 

Table 2‑1...... Development Criteria. 2-13

Table 2‑2...... Summary of Alternative Options Considered. 2-18

Table 3‑1...... Hong Kong Air Quality Objectives (mg/m3)(i) 3-2

Table 3‑2...... Traffic Forecast in Year 2027. 3-4

Table 3‑3...... Air Quality at Yuen Long Monitoring Station in Past Five Years. 3-5

Table 3‑4...... Locations of Representative Air Sensitive Receiver 3-5

Table 4‑1...... Relevant Noise Standards for Planning Purposes. 4-2

Table 4‑2...... Noise Standards for Daytime Construction Activities. 4-2

Table 4‑3...... Area Sensitivity Ratings (ASRs) 4-3

Table 4‑4...... Acceptable Noise Levels (ANLs) 4-3

Table 4‑5...... Measured Noise Levels. 4-4

Table 4‑6...... Identified Noise Sensitive Receivers within 300m from the Boundary of Project Area. 4-6

Table 4‑7...... Horizontal Distances between the Assessment Points of Representative NSRs and the Notional Centre of Each Phase for Construction Stage. 4-6

Table 4‑8...... Assessment Points of the Representative NSRs for Operational Stage. 4-7

Table 4‑9...... Inventory of Noise Sources at Each Phase – During Construction. 4-9

Table 4‑10.... Summary of Open Storage Site Noise Measurement Results at Point F. 4-11

Table 4‑11.... Traffic Flow Forecast of Existing and Future Road Networks (Year 2027) 4-11

Table 4‑12.... Maximum Predicted Unmitigated Construction Noise Levels at Representative NSRs. 4-12

Table 4‑13.... Predicted Noise Levels at Representative NSRs. 4-13

Table 4‑14.... QPME to be used at the Construction Site. 4-14

Table 4‑15.... Maximum Predicted Mitigated Construction Noise Levels at Representative NSRs with the use of QPME  4-15

Table 4‑16.... Maximum Predicted Mitigated Construction Noise Levels at Representative NSRs with the uses of QPME, Noise Barriers and Site Hoardings. 4-16

Table 5‑1...... Standards for effluents discharged into Group C inland waters (All units in mg/L unless otherwise stated; all figures are upper limits unless otherwise indicated) 5-2

Table 5‑2...... Standards for effluents discharged into Group D inland waters (All units in mg/L unless otherwise stated; all figures are upper limits unless otherwise indicated) 5-3

Table 5‑3...... Key Water Quality Objectives for inland waters in Deep Bay Water Control Zones. 5-4

Table 5‑4...... Summary of River Water Quality at Nearby Fairview Park Nullah in the Deep Bay Water Control Zones between 2002 and 2005 (Source: River Water Quality in Hong Kong in 2002 – 2005 (EPD)) 5-6

Table 5‑5...... In-situ Water Quality Testing Parameters. 5-8

Table 5‑6...... Water Quality Testing Parameters in Laboratory. 5-9

Table 5‑7...... Summary of Water and Sediment Quality Monitoring Results in Dry Season (For Monitoring Stations WM1 to WM7) 5-9

Table 5‑8...... Summary of Water Quality Monitoring Results in Wet Season (For Monitoring Stations WM1 to WM7 & WM11 to WM13) 5-10

Table 5‑9...... Summary of In-situ Water Quality Monitoring Results in Dry Season (For Monitoring Station WM8 to WM10) 5-12

Table 5‑10.... Summary of In-situ Water Quality Monitoring Results in Wet Season (For Monitoring Station WM8 to WM10) 5-12

Table 5‑11.... Summary of Key Water Quality Objectives Compliance for the Water Quality Monitoring Station WM1 to WM7 and WM11 to WM13. 5-12

Table 6‑1...... Design Unit Load Factors. 6-3

Table 6‑2...... Pollutant Loads arising from the Raw Sewage of the Proposed Development 6-5

Table 7‑1...... Potential contaminants. 7-11

Table 7‑2...... General hazardous effects of contaminants potentially present 7-12

Table 7‑3...... Ground conditions encountered and depth of subsamples tested. 7-13

Table 7‑4...... Summary of chemical test results on soil samples. 7-14

Table 7‑5...... Summary of chemical test results on ground water samples. 7-17

Table 7‑6...... Summary of additional TPH test results on ground water samples. 7-17

Table 7‑7...... Summary of land contamination locations. 7-18

Table 7‑8...... Criteria for the chemical screening of sediment (from ETWB(W)TC 34/2002) 7-23

Table 7‑9...... Criteria for classification of sediment (from ETWB(W)TC 34/2002) 7-23

Table 7‑10.... Criteria for disposal of sediment at sea. 7-23

Table 7‑11.... Depth of marine sediment encountered and subsamples tested. 7-25

Table 7‑12.... Samples for Tier III biological testing. 7-26

Table 7‑13.... Results of Tier III Testing. 7-26

Table 7‑14.... Results of Tier III Testing. 7-26

Table 7‑15.... Summary of chemical screening results and sediment classification. 7-27

Table 7‑16.... Depth of pond deposit encountered and tested for TOC.. 7-30

Table 7‑17.... Results of Gas Spike Test Survey. 7-32

Table 7‑18.... Results of TOC Testing on Pond Mud. 7-33

Table 7‑19.... Assessment of Biogas potential using TOC results. 7-36

Table 7‑20.... Percentage % of methane emitted after June 2006. 7-36

Table 7‑21.... Maximum potential CH4 generation in June 2008. 7-37

Table 7‑22.... Estimated volume and classification of excavated sediment 7-38

Table 8‑1...... Habitats present in Project Area and Assessment Area. 8-13

Table 8‑2...... Mean and maximum number of individuals of bird species of conservation importance and wetland-dependent bird species recorded on morning transect counts in Project Area (PA) and in other parts of the Assessment Area (AA), April 2005-June 2006. (Level of Concern based on Fellowes et al. 2002) 8-14

Table 8‑3...... Wetland-dependent bird species recorded in the Tam Kon Chau count area on monthly waterbird counts conducted by the Hong Kong Bird Watching Society, April 2005-March 2006 (data from Anon 2005, Anon 2006a) 8-17

Table 8‑4...... Heights of ardeids flying over the Project Area, June 2006. 8-19

Table 8‑5...... Summary of birds using Flight paths 1, 2 and 3, May-June 2006. 8-20

Table 8‑6...... Relative abundance of herpetofauna species recorded in the Project Area and in other parts of the Assessment Area, April 2005 – June 2006. 8-22

Table 8‑7...... Relative abundance of fish species recorded in Project Area and in the drainage channel by Palm Springs, April 2005 – June 2006. 8-22

Table 8‑8...... Butterfly species recorded in the Project Area (PA) and in other parts of the Assessment Area (AA) during surveys, May 2005 – June 2006. 8-23

Table 8‑9...... Dragonfly species recorded in the Project Area (PA) and in other parts of the Assessment Area (AA) during surveys, May 2005 – June 2006. 8-25

Table 8‑10.... Number of aquatic invertebrates recorded from sampling locations around the Project Area, 2005-2006. 8-26

Table 8‑11.... Ecological Evaluation of Grassland Habitats. 8-27

Table 8‑12.... Ecological Evaluation of Seasonal Marsh. 8-28

Table 8‑13.... Ecological Evaluation of Freshwater Marsh/Reedbed. 8-30

Table 8‑14.... Ecological Evaluation of Fishponds. 8-31

Table 8‑15.... Ecological Evaluation of Drainage Channels/ Ditches. 8-33

Table 8‑16.... Ecological Evaluation of Woodland Habitats. 8-34

Table 8‑17.... Ecological Evaluation of Plantation Habitats. 8-35

Table 8‑18.... Ecological Evaluation of Active and Inactive Dry Agricultural Land. 8-36

Table 8‑19.... Ecological Evaluation of Developed Area, Bare Ground and Wasteland. 8-37

Table 8‑20.... Potential Direct Ecological Impacts to habitats in Project Area without mitigation measures. 8-38

Table 8‑21.... Potential Ecological Impacts to bird species of conservation importance in Project Area, without mitigation measures. 8-41

Table 8‑22.... Potential Ecological Impacts to Scarlet Basker and Danaid Egg-fly in Project Area, without mitigation measures. 8-44

Table 8‑23.... Potential Indirect Ecological Impacts to habitats in the Assessment Area without mitigation measures. 8-45

Table 8‑24.... Potential Ecological Impacts from pollution of watercourses and Deep Bay without mitigation measures. 8-47

Table 8‑25.... Potential Disturbance Impacts to waterbirds of conservation importance in Assessment Area without mitigation measures. 8-49

Table 8‑26.... Potential Ecological Impacts to egretries in Assessment Area without mitigation measures. 8-51

Table 8‑27.... Potential Ecological Impacts to non-breeding bird flight paths without mitigation measures. 8-53

Table 8‑28.... Summary of Potential Ecological Impacts in the absence of Mitigation Measures. 8-55

Table 8‑29.... Summary of Potential Ecological Impacts before and after adoption of Mitigation Measures. 8-65

Table 9‑1...... AFCD Figures on HKSAR Pond Culture Fisheries. 9-3

Table 9‑2...... Fishponds Status and Area in the Project Area. 9-4

Table 9‑3...... Evaluation of Fisheries Impact 9-6

Table 11‑1.... Relationship between Receptor Sensitivity and Impact Magnitude in Defining Impact Significance. 11-5

Table 11‑2.... Assessment of Layout Options against Landscape / Visual Criteria. 11-25

Table 11‑3.... Proposed Construction Phase Landscape and Visual Mitigation Measures. 11-27

Table 11‑4.... Proposed Operation Phase Landscape and Visual Mitigation Measures. 11-28

Table 11‑5.... Significance of Landscape Impacts in Construction and Operation Phases (Negative Impacts unless otherwise stated) 11-34

Table 11‑6.... Significance of Visual Impacts in the Construction and Operation Phases (Note: All impacts negative unless otherwise noted) 11-56

Table 12‑1.... Impacts Summary. 12-1

 

List of Plates

 

Plate 1.1                    Aerial Photo Showing the Proposed Development and the adjacent Environment

Plate 8.1                    Grassland

Plate 8.2                    Seasonal Marsh

Plate 8.3                    Freshwater Marsh/ Reedbed

Plate 8.4                    Active Fishpond

Plate 8.5                    Abandoned Fishpond

Plate 8.6                    Drainage Channel/ Ditch

Plate 8.7                    Secondary Woodland

Plate 8.8                    Plantation

Plate 8.9                    Active Dry Agricultural Land

Plate 8.10                  Inactive Dry Agricultural Land

Plate 8.11                  Wasteland

Plate 8.12                  Bare Ground

Plate 8.13                  Developed Area

Plate 9.1                    Fishpond in maintenance stage (not in the site, refer to Figure 9.1 for location)

Plate 9.2                    Abandoned fishpond with reeds growing (refer to Figure 9.1 for location)

Plate 9.3                    Recreational fishing ground at Wo Shang Wai Village

Plate 9.4                    Wetland dependent birds foraging in partially drained fishpond

Plate 9.5                    Release of fish fingerlings into fishpond after maintenance                               

Plate 9.6                    Capturing freshwater shrimps and Mosquito Fish in Mai Po fishpond

Plate 9.7                    Mosquito Fish captured in the fishponds

Plate 9.8                    Brackish fishponds in Mai Po

Plate 9.9                    Brackish fishes cultured in Mai Po fishponds

Plate 10.1                  Ancestral Hall (Hin Hing Tong) in Mai Po Village

Plate 10.2                  Ancestral Hall in Wo Shang Wai Village

 

 

List of Figures

 

Figure 1.1                 Locations and Assessment Area of the Proposed Development Site

Figure 1.2                 Location of Conservation Area and Buffer Area Boundaries

Figure 1.3                 Standing Water patches Observed in Dry Season

Figure 1.4                 Location of Gleyed Soil

Figure 1.5                 Extract of Relevant OZP

Figure 2.1                 Preliminary Development Concept

Figure 2.2                 Generation of Options

Figure 2.3a               Schematic “Rectangular” Development

Figure 2.3b               Concept Layout Rectangular development (3 and 4 Storeys)

Figure 2.4a               Schematic “Horse Shoe” Concept

Figure 2.4b               Concept Layout Nucleated (Horse Shoe) (4 Storeys)

Figure 2.5                 Sketch Master Layout Plan Option A – All 2.5/3-Storey Houses

Figure 2.6                 Sketch Master Layout Plan Option B – All 6-Storey Apartments

Figure 2.7                 Sketch Master Layout Plan Option C – Mixed Height Scheme

Figure 2.8                 Sketch Master Layout Plan Option D – 2.5/3-Storey Houses with Duplex-on-Duplex

Figure 2.9                 Sketch Master Layout Plan Option E – 2.5/3-Storey Houses

Figure 2.10               Sketch Master Layout Plan Option F – 2.5/3-Storey Houses with Duplex-on-Duplex

Figure 2.11               Phase Layout Plan for Construction

Figure 3.1                 Location of the Air Sensitive Receivers

Figure 4.1                 Assessment Area of the Proposed Development Site

Figure 4.2                 Location of Representative Noise Sensitive Receivers (NSRs) in Construction Phase

Figure 4.3                 Locations of Representative Noise Sensitive Receivers (NSRs) in Operational Phase

Figure 4.4                 Alignment of Site Access Road and Haul Road

Figure 4.5                 Location of Baseline Noise Measurement

Figure 4.6                 Minimum Height Required for Proposed Noise Barriers and Site Hoardings

Figure 4.7                 Cross-section Diagram Showing Proposed Noise Barriers

Figure 4.8                 Cross–Sectional Diagrams of Four Types of Houses in Residential Development

Figure 4.9                 Computer Plot of Noise Model

Figure 5.1                 Existing Drainage Pattern in Wo Shang Wai

Figure 5.2                 Water Quality Sampling Locations

Figure 5.3                 Tentative Drainage Discharge Arrangement

Figure 6.1                 Planned Major Sewerage Works in Northwest New Territories from DSD

Figure 6.2                 Proposed Final Sewage Discharge Point

Figure 7.1                 Current Land Use at the Project Area August 2006

Figure 7.2                 Land Contamination Assessment Borehole Locations

Figure 7.3                 Contaminated Land Excavation

Figure 7.4                 Management Framework for Dredged/Excavated Sediment

Figure 7.5                 Sediment Assessment Borehole Locations

Figure 7.6                 Gas Spike Survey and Biogas Investigation Locations

Figure 7.7                 Marine Sediment Excavation

Figure 8.1                 Sites of known ecological value close to the Project Area

Figure 8.2                 Survey transects and sampling locations

Figure 8.3                 Habitats present in Project Area and Assessment Area

Figure 8.4                 Bird Flight Paths over the Project Area

Figure 9.1                 Fishponds Status Around Wo Shang Wai on 18 November 2005

Figure 10.1               Potential Cultural Heritage Resources

Figure 11.1A            Extract of Relevant OZP

Figure 11.1B            Plan of ZVI and VSRs

Figure 11.2               Landscape Resources (Plan)

Figure 11.3               Landscape Resources (Views) (Sheet 1 of 12)

Figure 11.4               Landscape Resources (Views) (Sheet 2 of 12)

Figure 11.5               Landscape Resources (Views) (Sheet 3 of 12)

Figure 11.6               Landscape Resources (Views) (Sheet 4 of 12)

Figure 11.7               Landscape Resources (Views) (Sheet 5 of 12)

Figure 11.8               Landscape Resources (Views) (Sheet 6 of 12)

Figure 11.9               Landscape Resources (Views) (Sheet 7 of 12)

Figure 11.10             Landscape Resources (Views) (Sheet 8 of 12)

Figure 11.11             Landscape Resources (Views) (Sheet 9 of 12)

Figure 11.12             Landscape Resources (Views) (Sheet 10 of 12)

Figure 11.13             Landscape Resources (Views) (Sheet 11 of 12)

Figure 11.14             Landscape Resources (Views) (Sheet 12 of 12)

Figure 11.15             Landscape Character Areas (Plan)

Figure 11.16             Photo Views of Landscape Character Areas (1 of 2)

Figure 11.17             Photo Views of Landscape Character Areas (2 of 2)

Figure 11.18             Section Showing Derivation of ZVI

Figure 11.19             Photos of VSR Views (1 of 5)

Figure 11.20             Photos of VSR Views (2 of 5)

Figure 11.21             Photos of VSR Views (3 of 5)

Figure 11.22             Photos of VSR Views (4 of 5)

Figure 11.23             Photos of VSR Views (5 of 5)

Figure 11.24A          Landscape and Visual Mitigation Measures (1 of 7)

Figure 11.24B          Landscape and Visual Mitigation Measures (2 of 7)

Figure 11.25A          Landscape and Visual Mitigation Measures (3 of 7)

Figure 11.25B          Landscape and Visual Mitigation Measures (4 of 7)

Figure 11.25C          Landscape and Visual Mitigation Measures (5 of 7)

Figure 11.25D          Landscape and Visual Mitigation Measures (6 of 7)

Figure 11.26             Landscape and Visual Mitigation Measures (7 of 7)

Figure 11.27             Landscape Resources Impacts in Construction Phase

Figure 11.28             Residual Landscape Resources Impacts in Operation Phase

Figure 11.29             Residual Landscape Character Impacts in Construction Phase

Figure 11.30             Residual Landscape Character Impacts in Operation Phase

Figure 11.31             Residual Visual Impacts in Construction Phase

Figure 11.32             Residual Visual Impacts in Operation Phase

Figure 11.33             Photomontage A – View from Palm Springs Boulevard, Palm Springs

Figure 11.34             Photomontage B – View from Santa Monica Avenue, Royal Palms

Figure 11.35             Photomontage C – View from Wo Shang Wai Village

Figure 11.36             Photomontage D – View from Tam Kon Chau Village

Figure 11.37             Photomontage E – View from Tam Kon Chau Road

Figure 11.38             Photomontage F – View from Mai Po Lo Wai

Figure 11.39             Photomontage G – View from Mai Po Nature Reserve

 

 

List of Appendices

 

Appendix A      EIA Study Brief No. ESB - 131/2005

Appendix B-1    Application for Planning Permission at OU(CDWRA) Zoning

Appendix B-2    Construction Programme

Appendix C       Air Quality (Not used)

Appendix D      Noise

Appendix E       Water Quality

Appendix F       Sewage

Appendix G       Ecology

Appendix H      Wetland Restoration Plan

 

 

 

 


1                        INTRODUCTION

 

PREFACE

 

Wo Shang Wai to the north of Royal Palms and Palm Springs is zoned “OU(CDWRA)”.  This area comprises formed land, fish ponds filled prior to the publication of the Mai Po and Fairview Park Interim Development Permission Area (IDPA) Plan, and fragmented and partially filled marshland.  The western portion is currently mostly vacant while the eastern portion is currently partly vacant and partly occupied by a mix of uses including open storage uses, container yards and container vehicle parks.

 

The planning intention of this location is to provide incentive for the restoration of degraded wetlands adjoining existing fish ponds and to encourage the phasing out of sporadic open storage and port back-up uses on degraded wetland.  This can be achieved through comprehensive residential and/or recreational development to include wetland restoration area.  Development or redevelopment schemes on the degraded wetlands directly adjoining the existing continuous and contiguous fish ponds should include wetland restoration and buffer proposals to separate the development from and minimize its impact on the fish pond areas.  Any new building should be located farthest away from Deep Bay. (Approved Mai Po and Fairview Park OZP No. S/YL - MP/6).

 

1.1                    Background

 

1.1.1.             In March 2005 the Project Proponent, Profit Point Enterprises Limited (Ltd), acquired a development site in Yuen Long at Wo Shang Wai, as shown on Figure 1.1.  The site has evolved from tidal flats for fishponds to infilled fishponds during the 1980’s until 1991 almost 15 years before the Project Proponent obtained the site. 

 

1.1.2.             The statutory planning intent of the site at Wo Shang Wai is to provide an incentive for the restoration of degraded land through comprehensive residential and/or recreational development to include a wetland restoration area. It is also the intention of the zoning plan to encourage the removal of existing sporadic open storage uses on degraded land in the New Territories.  The overarching objective of this Project is thus to formulate a land use system with creative layout design which will simultaneously benefit both the planned residential community and the created wetland and be sustainable in the long term.  The Project will allow wetland restoration to be realised in harmony with residential development.  It allows an opportunity for innovative ideas to be showcased to demonstrate that it is possible to achieve the planned intent to upgrade degraded areas in the New Territories in a sustainable manner with ecological enhancement to the Wetland Buffer Area within which the development site lies.

 

1.1.3.             The Project, and thus the EIA has also sought ways to minimise impacts to acceptable levels and to harmonise the apparently conflicting concepts of providing residential developments and the adjacent sensitive ecology in the Deep Bay Buffer Zone.  In order to put the proposed development into context it is important to note that the site is bounded on three sides by existing residential development and is in an area which has already been disturbed by development as illustrated in Plate 1.1. 

 

 

1.1.4.             In April 2005 Mott Connell Ltd (MCL) was commissioned to undertake an EIA for this project.  A Project Profile was prepared and submitted to the Director of Environmental Protection (EPD), and in September 2005 a Study Brief No. ESB – 131/2005 for the “Proposed Comprehensive Development at Wo Shang Wai, Yuen Long” was issued.  The EIA has been conducted by MCL with Urbis providing the urban planning and design, landscape and visual impact assessments.  Masterplan and Allied Environmental Consultant Limited were also engaged to provide statutory planning inputs and noise impact assessment respectively to the EIA.  In addition to the foregoing the Project has also benefited from ecological inputs from Asia Ecological Consultants (AEC) and Ecology and Environment, Inc. (E&E).  AEC has principally been responsible for input to the Ecological Assessments and developed the wetland restoration plans as well as providing suggestions on the management and maintenance aspects.  In addition to which, the Wetland Management arrangement have been reviewed by one of Hong Kong’s most experienced wetland lawyers, John Davison.  The Project has also benefited from the adoption of the Continuous Public Involvement (CPI) process in which members of the public and interested bodies have been consulted at various stages of the Project development.  The feedback received has been considered and used as appropriate in the development and refinement of the planned layout for this development project.

 

1.2                    The Project

 

History and Existing Condition of the Site

 

1.2.1               As revealed in the Study on the Ecological Value of Fishponds prepared for Government in 1997, the Project Area was filled by 1991.  Since then, the northeastern side of the Project Area has been used as open storage while the remaining area has remained vacant.

 

1.2.2               The existing habitat types within the proposed comprehensive development include developed area in active use (open storage for containers and lorry parking), bare ground (site access), grassland, seasonal marsh, freshwater marsh/reedbed and drainage ditches.  The Project Area is surrounded by residential developments, Wo Shang Wai village, fishponds and an open storage area.  The site context is shown on Figure 1.1 whilst Figure 1.2 illustrates the Project Area in relation to the Deep Bay Conservation Area and Wetland Buffer Area boundaries.

 

1.2.3               As the proposed project includes wetland restoration it is important to define the site using accepted terminology.

 

               Definition of Wetland under the “Ramsar Convention” is:

 

1.2.4               “Wetlands are areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water, the depth of which at low tide does not exceed six metres.”

 

1.2.5               The Working Definition of Wetland as per the “Corps of Engineers, Wetlands Delineation Manual” Wetlands Research Program Technical Report Y-87-1, 1987, which is more specific in terms of characterisation of a particular site, is as follows:

 

 

1.2.6               Wetland is defined as a site containing the following features:

 

·         presence of wetland hydrology;

·         presence of hydric soil; and/or

·         presence of predominantly wetland vegetation.

 

1.2.7               At Wo Shang Wai the ecological surveys which were conducted between April 2005 and June 2006 recorded 66 plant species within the site itself.  The vegetation observed on site is typically freshwater marsh/reedbed, seasonal marsh and grassland, with reed grass Phragmites australis and common grasses / herbs such as Brachiaria mutica, Panicum spp., Paspalum spp. respectively.  Riparian vegetation along the drainage ditches within the site boundary is typical of those found in the northwest New Territories fishpond areas including Brachiaria mutica, Panicum spp., Paspalum spp., Eleusine indica and Bidens alba.  No rare or protected plant species of conservation importance were identified under the Study.  More details on the ecology of the site are given in Chapter 8 of this EIA.

 

1.2.8               From on-site observations, there are patches of standing water on site during the dry season as illustrated on Figure 1.3.  As described later in this EIA the soils have been tested to determine their characteristics from, inter alia, a hydric soil perspective.  No evidence of hydric soils exists except in five locations on the former fish pond bunds there is some indication of gleyed soil; refer to Figure 1.4. This suggests some wetland function, which is not unexpected considering the historical land use of the Project Area as bunded fishponds.  The extent of the patches of standing water and the distribution of freshwater marsh vegetation is around 23% of the total Project Area. In summary the Project Area displays some wetland characteristics which have been considered when developing the design of the Project and the restored wetland in terms of both extent and component features.

 

Rationale of a Wetland Restoration Scheme with Residential Development

 

1.2.9               The rationale for the wetland restoration scheme with residential development is to restore part of the previously filled fishpond area to wetland with proper management in the operation stage.  The Study on Ecological Value of Fishponds in Deep Bay Area (Aspinwall, 1997) showed that the area of scattered open storage along the boundary of the Conservation Area (CA) caused significant decreases in ardeid numbers using the fishponds, while the residential areas at the southern boundary were identified as significantly less intrusive than the open storage.  The proposed residential development with wetland creation will eradicate the open storage uses that impact on bird numbers and restore the function of the wetland, thereby enhancing the ecological value of the Deep Bay Wetland Ecosystem.  The restored wetland will:

 

·         compensate for the loss of habitat as a result of proposed development;

·         provide flood protection to the surrounding developed area;

·         provide life support by increasing habitat heterogeneity and thus increasing the biodiversity of the area;

·         provide ecological linkages between the site and the CA; set a buffer between the residential development (set-back) and the existing fishponds area to the north of the Project Area; and

·         increase the biodiversity of the site and encourage various forms of wildlife.

Statutory Planning Intention of the Site

 

1.2.10            According to the Approved Mai Po and Fairview Park OZP No. S/YL-MP/6, the Other Specified Uses (Comprehensive Development and Wetland Restoration Area) [OU(CDWRA)] zone is intended to provide an incentive for the restoration of degraded wetlands through comprehensive residential and/or recreational development to include a wetland restoration area.  It is also intended to phase out existing sporadic open storage and port back-up uses on degraded wetlands.  However, new buildings should be located as far as practical away from Deep Bay to minimise disturbance to the CA.  The maximum plot ratio of 0.4 and maximum building height of 6 storeys including car park is allowed under the statutory plans, with ancillary facilities to the domestic development disregarded in the plot ratio calculation.

 

Purpose and Objectives of the Proposed Project

 

1.2.11            The purpose of the Project is to develop the site in accordance with the Planning Objectives and permitted conditions stated in the Outline Zoning Plan (OZP). This permits comprehensive residential development with wetland restoration.  The Project Proponents’ objective is to provide high quality residential development which is in harmony with nature and its surroundings, while complying with the planning intention of the site.

 

1.2.12            The findings of the Environmental Impact Assessment (EIA) and in particular the ecological surveys and assessments have provided the basis for the development assumptions.  For example, the bird flight paths and use of the site by different species groups gives an indication of the functions of the site.  This information was then used in the analysis of the type of restored wetland to be developed.  This information was also used in the development of the layout of the whole site, as well as in the layout of the proposed residential developments and in the building form, disposition and height.

 

Significance of the Proposed Project

 

1.2.13            The Project Area is adjacent to existing developed areas, where the building form and landscaping provide few opportunities for biodiversity.  The adjacent developments have also been created from infilled fishponds and thus have a similar basis for development. The difference between the adjacent developments and the proposed development relates to the fact that the planning intent for the Project Area combines the comprehensive development with wetland restoration.  In essence, the intent is that the proposed development should be in harmony with its surroundings including the residential developments which are close to the boundaries of the Project Area.  The wetland restoration proposals conform to the requirements of the Town Planning Board Guideline for Application for Developments within Deep Bay Area under Section 16 of the Town Planning Ordinance, TPB PG-No. 12B, (TPB 12B) and are in close proximity to the existing fishponds, thereby providing continuity and connectivity with the Conservation Area.

 

1.2.14            This development presumption is based on a series of guiding principles which were translated into development objectives and illustrated on the “bubble diagram” (see Figure 2.1).  The “bubble diagram” was drawn up using sound wetland design and management principles and has been reviewed and developed as the information and data became available from the ecological and other baseline surveys, as well as the planning guidelines including those defined in TPB PG-No. 12B.

Scenario without the Proposed Project

 

1.2.15            The scenario without the project would essentially be further environmental degradation and more ecological harm.  The existing temporary uses of the site may prevail, grassland and low shrubs would develop through natural succession, developing into tall grassland and low scrub.  Active vegetation management would be required on a regular basis to maintain the grassland at a low height otherwise there is the potential for unwelcome users of the site (rats, mice, illegal immigrants etc. who might hide in tall grass).  This is undesirable from a “good neighbour perspective”, and on the basis that in order to reduce the risk of grass fires, clearing of the site would need to take place frequently, which would reduce the ecological value of the site.  This scenario is described in more detail in Section 2 under consideration of the alternatives for development.

 

1.3                    EIAO and Designated Projects

 

1.3.1               As the Project Area is 21.36 hectares (ha) including two zones (Other Specified Uses (OU) and Village Type Development (V)), the Project has the status of a Designated Project under Item 1 of Schedule 3 of the EIA Ordinance (EIAO) (engineering feasibility study of urban development projects within an Assessment Area covering more than 20 hectares).

 

1.3.2               In addition to the above, the proposed residential development lies within the Deep Bay Buffer Zone 2 and is not “New Territories exempted houses”.  Thus item P1 of Schedule 2 of the EIAO also applies to this Project.

 

1.3.3               In the early stages of the Project it was identified that as there is no public sewerage system in the area for the discharge of the domestic effluent, the “No Net Increase” (of pollution) to Deep Bay also applies.  At the time of preparing the Project Profile the initial thinking was to provide a dedicated sewage treatment plant on-site with the possibility of reusing treated effluent within the development. Reuse of treated effluent from a treatment plant falls under item F4 of Part 1 of Schedule 2 of the EIAO and thus such an activity becomes a Designated Project in its own right.  However during the planning and assessment stage of the Project the Government committed to the provision of a sewerage system which will include the catchment from this development site.  Government has confirmed that the domestic effluent generated from this site can be discharged via the public sewer (on Castle Peak Road) and thus the timing of this development project has been phased to accord with the provision of the Government sewer.  Hence item F4 is no longer a relevant component of this Project.

 

1.4                    Continuous Public Involvement

 

1.4.1               From the outset, the Project Proponent has been committed to the Continuous Public Involvement (CPI) process in recognition of the fact that such an approach can assist in the smooth implementation of the Project. The CPI programme for this Project has included, but not been limited to, the involvement of community and conservation interest groups. The inputs and feedback on the development concepts and suggestions, particularly on the development and management issues associated with the wetland restoration, have been of particular value. Informal discussions with Government Departments such as the Environmental Protection Department (EPD), Agriculture, Fisheries and Conservation Department (AFCD), Drainage Services Department (DSD), Planning Department (PlanD), Transport Development (TD) and discussions with local interest groups, Nature and Conservation Groups including Conservancy Association, Hong Kong Bird Watching Society, World Wide Fund for Nature, Kadoorie Farm and Botanic Garden, Green Power, residents of Palm Springs and Royal Palms and international wetland experts have been fruitful and the feedback received has resulted in a more robust conservation component to the development plan.

 

1.5                    Scope

 

1.5.1               The scope of this EIA study covers the potential impacts arising from this Project during the construction and operation phases.  The EIA study has addressed the key issues identified in the aforementioned Study Brief as outline below:

 

·        noise impacts arising from construction and operation of the Project to the nearby village and residential areas;

·        dust impact arising from construction of the Project to the nearby air sensitive receivers (ASRs), as there is no on-site sewage treatment plant there is no sewage odour emanating from this development

·        landscape and visual impacts during construction and operation of the Project;

·        the potential water quality impacts caused by site formation, pond draining and filling, drainage diversion, and any other works activities during construction; the potential water quality impacts caused by the operation of the Project;

·        potential impacts on historical buildings/architectures and monuments;

·        terrestrial and aquatic ecological impacts, in particular the potential impacts disturbance and fragmentation to the adjacent recognized sites of conservation importance including, for example, the Mai Po Nature Reserve, Mai Po Inner Deep Bay Ramsar Site, Mai Po Village Site of Special Scientific Interest (SSSI), Mai Po Marshes SSSI, Inner Deep Bay SSSI, Wetland Conservation Area and Wetland Buffer Area (both were defined under Town Planning Board Guideline TPB PG-No. 12B) and important habitats such as fishponds and egretries, due to the construction and operation of the Project;

·        fisheries impacts during construction and operation of the Project;

·        collection and disposal of potentially contaminated dredged spoil arising from the Project; and

·        the short term and long term management of the proposed wetland restoration within the site including trust and financial arrangement.

1.6                    Objectives of the EIA Study

 

1.6.1               Under the Study Brief (ESB-131/2005), the objectives of the Environmental Impact Assessment (EIA) Study are:

 

(i)             to describe the Project and associated works together with the requirements for carrying out the Project;

(ii)           to identify and describe elements of community and environment likely to be affected by the Project and/or likely to cause adverse impacts to the Project, including both the natural and man-made environment;

(iii)          to identify and quantify all environmental sensitive receivers, emission sources and determine the significance of impacts on sensitive receivers and potential affected uses;

(iv)         to identify and quantify any potential losses or damage to flora, fauna and wildlife habitats;

(v)           to identify any negative impacts on sites of cultural heritage and to propose measures to mitigate these impacts;

(vi)         to identify and quantify any potential landscape and visual impacts and to propose measures to mitigate these impacts;

(vii)        to propose the provision of infrastructure or mitigation measures so as to minimise pollution, environmental disturbance and nuisance during construction and operation of the site;

(viii)      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;

(ix)         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;

(x)           to investigate the extent of secondary environmental impacts that may arise from the proposed mitigation measures and to identify constraints associated with the mitigation measures recommended in the EIA study, as well as the provision of any necessary modification;

(xi)         to identity, within the Assessment 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

(xii)        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 control measures adopted.

 

1.6.2               The Technical Requirements of the EIA Study comply with those specified in the Study Brief No. ESB - 131/2005 (which is appended as Appendix A for ease of reference).

 

1.7                    The Assessment Area

 

1.7.1               The Assessment Area encompasses all areas within 500m of the Project Area, comprising mostly residential uses (Palm Springs, Wo Shang Wai Village Houses, Royal Palms, Mai Po Lo Wai, Mai Po San Tsuen and Maple Gardens) and fishponds adjoining the Project Area.  Ecological assessments also take into consideration sites of ecological importance identified during the CPI process, including the egretries at Mai Po Village ‘satellite’, Tam Kon Chau and Mai Po Lung, which are located outside the 500m Assessment Area boundary but are within the foraging distance of breeding egrets. The Assessment Area defined for this project is illustrated in Figure 1.1. 

1.7.2               The development of the Project has considered the adjacent recognized sites of conservation importance, including but not limited to the Mai Po Nature Reserve, Mai Po Inner Deep Bay Ramsar Site, Mai Po Village Site of Special Scientific Interest (SSSI), Mai Po Marshes SSSI, Inner Deep Bay SSSI, Wetland Conservation Area and Wetland Buffer Area and important habitats such as fishponds and egretries.  It has also recognised that the ecological sensitivity of the surrounding area is crucial to the successful implementation of the Project.

 

1.7.3               Particular consideration has been given to the adoption of workable solutions and methods of work within the Deep Bay area while upholding the principles of conservation and ecological protection.  To this end the Deep Bay Guidelines have been followed and the construction programme has taken account of these guidelines which are fundamental to the assessment of noise impacts as detailed in Sections 4 and 8 of this EIA.  Development of short term and long term management for the proposed wetland restoration within the Project Area including financial arrangements is documented in a standalone document in Appendix H in accordance with the requirements of the Study Brief (item 3.9.2.4 (xv)).

 

1.8                    Programme

 

1.8.1               The overall programme for implementation of the Project is given in Appendix B-2.  The construction works are anticipated to commence in 2008 and to be completed in 2012, with population intake timed to accord with the availability of new regional infrastructure such as public sewers on Castle Peak Road.  As with any development project, the implementation of the works will be staged via a series of work packages.  Essentially the advance works which are being undertaken at present include site and ground investigation contracts, investigation for potential land contamination contracts, a Section 16 planning application for the proposed comprehensive development at Wo Shang Wai (which is in progress) as well as this EIA.

 

1.9                    Structure of the EIA Report

 

1.9.1               The EIA has been prepared to contain all the findings of the Study as follows:

 

·        Section 2 presents the consideration of alternative layout options and building height profiles as required under the Study Brief, construction methods and sequence works and describes selection of preferred scenario for the Project;

·        Section 3 describes the Air Quality Impact Assessment;

·        Section 4 describes the issues associated with Noise during and following construction, quantifies the impacts and recommends mitigation measures;

·        Section 5 presents the Water Quality Impact Assessment which include the potential problem of biogas on reclamation (pond filling);

·        Section 6 describes the Sewerage and Sewage Treatment Implications

·        Section 7 presents the Waste Management Implications;

·        Section 8 describes the Ecological Impact Assessment which is a combined report using the findings of the baseline survey and describing the development of the mitigation measures for the protection of the ecological resources and habitats.  The management package for the wetland restoration in the Project Area is appended to this EIA report;

·        Section 9 presents the Fisheries Impact Assessment;

·        Section 10 describes the Impact on Cultural Heritage;

·        Section 11 presents the Landscape and Visual Impact Assessment (LVIA) which is one of the components of the EIA;

·        Section 12 describes the Impact Summary;

·        Section 13 provides a summary of the Environmental Outcomes;

·        Section 14 presents the Environmental Monitoring and Audit (EM&A) Requirements;

·        Section 15 presents an Implementation Schedule; and

·        Section 16 presents a summary of the Conclusions of the EIA.


2                        CONSIDERATION OF ALTERNATIVES

 

PREFACE

 

Wo Shang Wai to the north of Royal Palms and Palm Springs is zoned “OU(CDWRA)”.  This area comprises formed land, fish ponds filled prior to the publication of the Mai Po and Fairview Park Interim Development Permission Area (IDPA) Plan, and fragmented and partially filled marshland.  The western portion is currently mostly vacant while the eastern portion is currently partly vacant and partly occupied by a mix of uses including open storage uses, container yards and container vehicle parks.

 

The planning intention of this location is to provide incentive for the restoration of degraded wetlands adjoining existing fish ponds and to encourage the phasing out of sporadic open storage and port back-up uses on degraded wetland.  This can be achieved through comprehensive residential and/or recreational development to include wetland restoration area.  Development or redevelopment schemes on the degraded wetlands directly adjoining the existing continuous and contiguous fish ponds should include wetland restoration and buffer proposals to separate the development from and minimize its impact on the fish pond areas.  Any new building should be located farthest away from Deep Bay. (Approved Mai Po and Fairview Park OZP No. S/YL - MP/6).

 

2.1                    Summary

 

2.1.1               This section of the EIA Report provides a description on the need for the Project and narrative on the alternatives considered, both of the conceptual layout of the whole site and of the building forms, building heights and possible detailed layouts.  The need for the Project is explained at the beginning of the Section and addresses the implications of the further degradation of the environment versus development.  The Section describes the development concept building process and the process for the consideration of development alternatives of the Project Area.  The Continuous Public Involvement (CPI) process is described herein and has been an important component of the process of developing and evaluating the alternatives.  This section responds directly to Sections 3.3 through 3.6 inclusive of the Study Brief.

 

2.2                    The Project Area

 

Background

 

2.2.1               The Project Area lies within an area designated for “Other Specified Uses” “Comprehensive Development to include Wetland Restoration Area” (OU(CDWRA)). The notes to the OZP make it clear that the planning intent for OU(CDWRA) is :

 

“this zone is intended to provide incentive for the restoration of degraded wetlands adjoining existing fishponds through comprehensive residential and/or recreational development to include wetland restoration area. It is also intended to phase out existing sporadic open storage and port back up uses on degraded wetlands. Any new buildings should be located farthest away from Deep Bay.”

 

 

2.2.2               The Project Area also falls within an area which is designated as Wetland Buffer Area (WBA) in the Town Planning Board Guidelines for Application for Developments within Deep Bay under Section 16 of the Town Planning Ordinance.  While the Guidelines are provided for general reference and are not binding on the Town Planning Board, they do however imply the underlying philosophy which is to encourage the restoration of lost fishponds and to provide a desirable wetland habitat around Deep Bay and the Mai Po Area.  Specifically :

 

“6.4 the intention of the WBA is to protect the ecological integrity of the fishponds and wetlands within the Wetland Conservation Area (WCA) and to prevent development that would have a negative off-site disturbance impact on the ecological value of fishponds……. As a substantial number of fishponds with the WBA have already been lost over time through filling and certain areas have been degraded by the presence of open storage use, these degraded areas may be considered as target areas to allow an appropriate level of residential/recreational development so as to provide an incentive to remove open storage use and/or to restore some of the fishponds lost.

 

6.5 Within the WBA, for development or redevelopment which requires planning permission from the Board, an ecological impact assessment would also need to be submitted. Development/redevelopment which may have negative impacts on the ecological value of the WCA would not be supported by the Board, unless the ecological impact assessment can demonstrate that the negative impacts could be mitigated through positive measures. The assessment study should also demonstrate that the development will not cause net increase in pollution load to Deep Bay.”

 

2.2.3               With the foregoing as the guiding principles, the assessment of the implications of development at Wo Shang Wai commenced.  In the first instance, prior to the issue of a Study Brief under the Environmental Impact Assessment Ordinance (EIAO), the following activities were undertaken:

 

·         Visits to the Project Area and adjacent areas to characterize the site and the Assessment Area.  This included the definition of the Project Area, its relationship with its nearest neighbours including the adjacent Royal Palms and Palm Springs and the WCA to the north.  The land uses in the off-site areas were identified and categorized in terms of their sensitivity to development, such as the egretries at Mai Po San Tsuen.

·         The history of the site was ascertained through examination of site records and aerial photographs.

·         The planning status was confirmed.

·         The constraints and opportunities for development were considered and compiled as a set of planning principles as illustrated in the “bubble diagram” (see Figure 2.1).

·         Initial ecological baseline surveys were carried out.

·         Initial environmental appraisals were conducted.

2.2.4               The next step in the assessment of the Project Area and its development potential was to undertake a preliminary environmental review such that an application for a Study Brief could be made.  This was affected by the preparation of a Project Profile which contained the development parameters and constraints which were illustrated in a “bubble diagram” (see Figure 2.1).

2.2.5               Upon receipt of the Study Brief the ecological impact and other impact assessments were undertaken to determine the existing conditions of the Project Area, the potential impacts associated with permitted development and the associated mitigation measures needed to ensure acceptability in terms of the requirements of the EIAO, its Technical Memorandum and the Study Brief.

 

History

 

2.2.6               In the 1940’s and 1950’s the Project Area comprised brackish rice paddies, and it was during the 1960s when fresh water fish farming prospered in the New Territories that the rice paddies were converted into fishponds.  With increased pressure for open storage activities in the North West New Territories (NWNT), the ponds were progressively filled from around 1987.  From the aerial photo taken on 18th August, 1990, it is evident that about 90% of the ponds in the site were filled with the remainder filled by 1991.  Part of the Project Area has been continuously used from that date as open storage and the parking of new vehicles.

 

2.2.7               The introduction of statutory planning control in the area to prevent infilling of ponds and proliferation of open storage uses commenced on 17 August 1990 with the gazettal of the Interim Development Permission Area (DPA) Plan.  In August 1991, with the publishing of the Mai Po and Fairview Park Development Permission Area Plan, the Project Area was zoned “Unspecified Use Area”.  Under both plans the existing open storage uses on the Project Area were permitted to continue as they had “existing use” status.

 

2.2.8               In June 1994 the Town Planning Board gazetted the new Outline Zoning Plan to replace the DPA plan, and on that plan the Project Area was zoned as “Conservation Area”.  An objection was lodged to that zoning and the Board accepted the argument that the Project Area in its form at that time had limited conservation value because of the existing land use.  On 27 October 2000 the Board gazetted an amendment to the Outline Zoning Plan under Section 6(7) of the Town Planning Ordinance to rezone the Project Area to the OU(CDWRA) zoning which exists at present (see Figure 1.5).  In doing so, the Board recognized the “existing use” rights of the Project Area for open storage and provided an incentive for the redevelopment of the site to provide residential development in conjunction with the creation of a new wetland conservation area.

 

2.2.9               The existing use rights for the Project Area therefore go back to 1990 and also relate to the situation when the zoning was changed in 2000.  These important dates must therefore be used when establishing the base case against which any wetland creation should be measured.  The applicant purchased the land in 2005, well after the present zoning of the Project Area was introduced.

 

Statutory Planning Intention for the Project Area

 

2.2.10            The Project Area is zoned ‘OU(CDWRA)’ with a small portion at site entrance zoned as ‘V’.  Accordingly, the proposed residential development shall follow these parameters:

 

Plot Ratio

0.4

Maximum Building Height

6 storey including car park

Layout Arrangement

Building farthest away from Deep Bay

Maximum GFA

82,800m2

2.2.11            According to the Approved Mai Po and Fairview Park OZP No. S/YL-MP/6, the OU(CDWRA) zone is intended to provide incentive for the restoration of degraded wetlands through comprehensive residential and/or recreational development to include wetland restoration area.  It is also intended to phase out existing sporadic open storage and port back-up uses on degraded wetlands.  However, new buildings should be located farthest away from Deep Bay.  A maximum plot ratio of 0.4 and maximum building height of 6 storeys including car park is allowed. The ‘V’ zone does not include density calculation and is merely proposed as access and amenity in terms of the proposed development.  Ancillary facilities to the domestic development may be disregarded in the plot ratio calculation.

 

The Need for the Project

 

2.2.12            The need for the project is derived directly from the statutory zoning of the Project Area by the Town Planning Board (TPB) as OU(CDWRA) with the expressed purpose of encouraging new residential development in degraded sites such as this. The implementation of the project provides a means to achieve the TPB’s intention of safeguarding the ecological integrity of Wetland Conservation Area (WCA) to the North and providing new wetland areas with compatible residential development.  Determining whether or not any proposed residential development with wetland restoration area will create ecological impacts to the Project Area or its surroundings needs to be considered in a rational manner with the ecological impact assessment being a key component of the assessment process.

 

2.2.13            The need for the Project has thus been considered taking full cognisance of the Town Planning Board Guidelines (TPB PG-No. 12B): 

 

“to allow an appropriate level of residential/recreational development so as to provide an incentive to remove the open storage use and/or to restore some of the fishponds lost.”

 

2.2.14            Reference has also been made to the Study on Ecological Value of Fishponds in Deep Bay Area (Aspinwall, 1997) which showed that the area of scattered open storage along the boundary of the Wetland Conservation Area (WCA) caused significant decreases in ardeid numbers using the fishponds, while the residential areas at the southern boundary were identified as significantly less intrusive than the open storage. The proposed residential development with wetland creation will eradicate the open storage uses that have potential negative impact on bird life.

 

Purpose and Objectives for the Proposed Project

 

2.2.15            The purpose of the project is to implement the Planning Intention for the site as stated in the planning notes of the OU(CDWRA) zone on the Outline Zoning Plan quoted above.  Furthermore TPB PG-No.12B states that:

 

Development proposals to restore lost fishponds or to replace existing undesirable uses by wetland habitats are encouraged.”

 


2.2.16            The objectives established for the project so as to achieve this purpose are:-

 

(a)          To determine the function of the existing habitats, assess the ecological impact of development and provide a comprehensive proposal which will enhance the ecological function of the site and contribute to the overall value of the Wetland Buffer Area and the Wetland Conservation Area.

 

(b)          To provide a viable high quality residential development in harmony with the conservation objectives of the zoning.

 

(c)          To provide for an increase in the wetland function provided by the site over the existing degraded situation.

 

(d)          To provide a comprehensive residential development with a plot ratio of 0.4 so as to provide support for the creation of a sustainable managed wetland.

 

(e)          To ensure that the form and height of the residential development is compatible with the general character of the area within the flexibility provided by the 6 storey height limit.

 

(f)           To establish clear conservation objectives which are compatible with the function that this wetland will provide in the Deep Bay context taking account of the locational constraints and the form of the development proposed on the site.

 

(g)          To provide an effective wetland and visual buffer to separate the residential part of the development from the “CA” zone to the north.

 

2.3                    Site Context

 

The Existing Site Conditions

 

2.3.1               The proposed Project is significant in that the Project Area is recognised by the TPB to be degraded and that action should be taken by the private sector to arrest further environmental degradation and ecological harm. The existing temporary uses are incompatible with the adjacent Conservation Area zoning and would benefit from being removed.  The continued degraded nature of the site is difficult to manage and creates a fire risk and community safety concerns.  An appropriate form of residential development with newly created wetland will add positively to the biological system of the Deep Bay Area and the broader regional ecological functions of Mai Po in a sustainable manner. 

 

2.3.2               The adjacent developed areas have a building form and landscaping which provides few opportunities for diverse wildlife.  The adjacent developments were also created from infilled fishponds and thus have a similar basis for development.

 

The Surrounding Conditions

 

2.3.3               The Project Area is located on the northern edge of the low-rise residential development at Palm Springs and Royal Palms.  In this respect it forms a transition between a development area and the fishponds to the north which are zoned as “Conservation Area” on the Outline Zoning Plan.  A part of the existing Palm Springs, residential development area is also located outside the western-most edge of the site and is between the site and the Mai Po Nature Reserve located a further 700 metres to the west.

 

2.3.4               The adjacent existing development is predominantly three storeys in height in accordance with the planning restrictions for the R(C) zone.  Along the north eastern boundary is the scattered village development of Mai Po San Tsuen and Mai Po Lo Wai villages interspersed with areas of open storage and other temporary uses.  Other than the existing commercial fishponds to the north of the Project Area, there is no feature which is of particular ecological or environmental sensitivity immediately adjacent to the site.

 

2.3.5               The existing habitat types within the proposed comprehensive development include developed area in active use (open storage for containers and lorry parking), bare ground (site access), grassland, seasonal marsh, freshwater marsh/reedbed and water ditches.  It is surrounded by a residential area, village development, fishponds and open storage.

 

2.3.6               The freshwater marsh/reedbed, seasonal marsh and grassland are secondary habitats developed on land filled over 15 years ago.  Vegetation is typical to those similar habitats located in the surrounding NWNT areas.  No rare or protected or species of conservation interest of flora were identified.  Fauna species recorded within the Project Area are common and widespread throughout the Deep Bay Area.

 

2.4                    Consideration of Alternatives

 

Introduction

 

2.4.1               The EIA Study Brief requires that consideration be given to alternative layout options and building profiles for the Project in arriving at the preferred option.  A description of the environmental factors taken into consideration is required and a comparison between the options is to be provided.  The preferred option should avoid or minimize adverse environmental effects to the maximum practicable extent.  In particular, consideration must be given to avoiding disturbance to the adjacent recognized sites of conservation importance and important habitats during the construction and operation of the project.  Where avoidance is not possible then minimisation and mitigation of potential impacts to acceptable levels is required.  The process outlined in Figure 2.1 and Figure 2.2, “Generation of Options”, illustrates how the principles of the “bubble diagram” were transposed into options or alternatives.

 

Working Up the Alternatives from Development Principles

 

2.4.2               At this juncture it is important to summarise the development principles which have been considered in the development of options or alternative development proposals.  It is also important to note that some of the development principles apply to all options and do not provide differentiation between options/alternatives/layouts.

 

Wetland Restoration

 

2.4.3               Wetland restoration is one of the statutory requirements laid down in the OZP No. S/YL-MP/6.  TPB PG-No. 12B “Application for Developments within Deep Bay Area under Section 16 of the Town Planning Ordinance” (April, 1999) defines Wetland Restoration as:

 

“Development proposals to restore lost fishponds or to replace existing undesirable uses by wetland habitats…”

 

and the definition of wetland habitat adopted by the TPB from Ramsar is :

 

“any area of marsh, fen, peatland or water whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including any area of marine water the depth of which at low tide does not exceed 6 metres, in which plants and/or animals live.”

 

2.4.4               Wetland Restoration is a term used to describe activities that return wetland from a disturbed or totally altered state to a previously natural condition.  The converted wetland not only restore the physical state but also the functional values, by the re-establishment of flora and fauna to enhance life support, flood control, recreational, educational, or other functional uses (Hammer, 1996).  From the analysis carried out as a result of the ecological assessments the wetland restoration area (WRA) will be 4.74 hectares (details provided in Section 8).  The functions of the proposed WRA are given in detail in Appendix H.

 

Buffering from Existing Ponds in the North

 

2.4.5               The Project Area is located in the Wetland Buffer Area (WBA) and adjacent to the Wetland Conservation Area (WCA) as identified in TPB PG-No. 12B. According to the Guideline, development in the WBA should provide a wetland and visual buffer to separate the development from the WCA, to minimise its impact on the wetland and to restore some of the lost fishponds to an appropriate form of wetland adjoining the WCA.

 

Building Form and Location

 

2.4.6               The OZP permits buildings up to six storeys in height.  However, consideration needs to be given to the form of other development in the area which is mainly of three storeys in height, such as at Royal Palms, Palm Springs, Fairview Park, Mai Po San Tsuen and Maple Garden.  The form of development proposed on the site should therefore be compatible with the general character of the neighbourhood in terms of height and also in visual impact terms. 

 

2.4.7               The OZP zoning also requires that any buildings be located as far as possible from the Mai Po Nature Reserve, and consideration should be given to the open nature of the general area between the Project Area and the Nature Reserve.  Consideration also needs to be given to the relationship to the residential development on the adjacent site, with regard to building height variation; building height; spacing between units and distance between building and Visually Sensitive Receivers (VSRs).

 

2.4.8               Adequate open space provision must be provided in the development such that it fulfils HKSAR Government Planning Standards and Guidelines but also conforms to what are currently regarded as basic sustainable development principles including green space corridors, areas for groundwater recharge and opportunities for sustainable community interaction.

2.4.9               Building form and layout are key factors which have been examined when considering the different alternatives.

 

Access to the Project Area

 

2.4.10            The only vehicle access to the Project Area is via the Castle Peak Road – Mai Po section.  The access passes through the Village zone before entering the OU(CDWRA) zone.  This access shall also serve as the future access to the site after appropriate upgrading works.  All options will use this access, therefore there are no differentiating factors for this consideration.

 

Parking Provision for Residential Development

 

2.4.11            As the Project Area is remote from mass transit and due to the large unit size, car usage is expected to be high.  According to the HKPSG requirement, the minimum parking varies according to the flat size and the distance from a railway station.  The development is likely to have mainly large units and the parking standard is stipulated as a minimum with possible greater provision being subject to Transport Department’s approval.  The parking standard calculation results in a minimum requirement of approximately 1.5 car parking spaces for each dwelling unit.  However, it is considered that a higher parking provision than 1.5 spaces per unit may be appropriate and this will be subject to further discussion with Transport Department.  This is not a factor which will differentiate between the options.

 

No Community Facility Needed

 

2.4.12            Given the small anticipated population of the development, no particular community facilities are required.  However, the normal provision of a Club House will be provided for the residents’ use for all options.

 

Site Formation Level Relative to Water Level

 

2.4.13            The minimal site formation level for buildings in Hong Kong in general is +5.5m to prevent flooding.  The difference between building level, water level and level of existing channels and ponds shall be taken into account when designing the area for building works and when forming the waterscape design.  This is not a factor which will differentiate between the options considered.

 

Adjacent Site within the same OU(CDWRA)

 

2.4.14            Part of the OU(CDWRA) zone falls outside the proposed site boundary and is in separate ownership.  That portion of the OU(CDWRA) zone may therefore be developed independent of the current proposal.  The existing vehicular access to that Project Area will be suitable for future up-grading to serve permanent development of the site.  It also fronts onto an adjacent area of fishponds zoned as ‘Conservation Area’ and there is scope for a wetland area to be created adjacent to the existing ponds.  The implementation of the current proposal will therefore not adversely affect the long-term achievement of the desired form of development within the whole zone.  Paragraph 9.9.4 of the Explanatory Statement recognises that the zoning may be implemented in parts.  The Project Area has incorporated a buffer between this area and the residential and wetland area in the form of the Clubhouse and open areas.

No Net Increase in Pollution Load to Deep Bay

 

2.4.15            To protect water quality and ecosystems in and around Deep Bay, this Project within the WBA should not cause a net increase in the pollution load to Deep Bay (i.e. no net increase requirement) as specified in the Town Planning Board Guidelines No. 12B.  The government has a confirmed program for the construction of public sewers along Castle Peak Road.  It is therefore intended that the development should not be completed and occupied before the availability of the public sewer.  It is understood that the current program is for the public sewer to be completed in 2012 and that is compatible with the development program for this Project.  A sewer will therefore be laid from the site to connect to the new public sewer, thus there is no difference between any of the alternatives considered for this element.

 

Avoidance of Key Ecological Impact

 

2.4.16            The existing conditions within the Project Area are such that any development would have unavoidable negative impacts to existing wetland habitats, especially through fragmentation of this habitat from nearby existing wetlands.  Thus it is considered that retention of existing wetlands within the Project Area is not feasible. The only feasible and desirable option is to compensate for the loss of these wetlands by creation of a Wetland Restoration Area which would be located to the immediate south of the existing offsite fishpond habitats.  This will permit enhancement of the wetland habitats within the Project Area, through habitat management and through integration with contiguous wetland habitats in the Deep Bay ecosystem.  This will have the additional benefit of creating a buffer area between the residential development of the Project Area and fishpond habitats to the north of the Project Area, minimizing potential disturbance impacts to wetland-dependent birds using these fishponds. The type, nature, size, dimension, functions and other design parameters of the habitats to be created will be carefully considered to achieve a robust eco-system.  To minimize impacts on the ecology, existing ecological resources including the reeds and some native vegetation within and surrounding the Project Area will be reused as far as possible. Suitable areas of topsoil on the site will also be retained for the use in landscape planting as far as possible. To minimize the disturbances to both on-site habitats and to provide maximum linkage to surrounding fishponds, the wetland restoration area will be constructed at the earliest stage, to form a buffer between the construction site and the Conservation Area.  This is a key element in considering the alternatives.

 

Adjacent Ponds Wo Shang Wai Village

 

2.4.17            There is an existing pond located to the south of the Project Area in Wo Shang Wai Village.  There are also ponds within the Palm Springs development.  The latter ponds are zoned ‘CA’ while the one in the village is zoned for residential development in the long term.  While there may be relatively little ecological value in these two adjacent water bodies, it is considered that their existence should be taken into account when preparing the layout for the site.  While there is no intention of establishing a physical link with them, it may be advantageous to consider ways of trying to improve the visual corridor of these water bodies to the fishponds located to the north of the Project Area.

 

 

 

Water Supply to Wetland Features

 

2.4.18            Wetland features need water to perform ecological and landscaping functions.  Rain water will be the source of water and historic data indicates that the normal rainfall expected in the area should provide adequate water in all but exceptionally dry years.  In the dry months of the year there will be some natural draw-down of water by evaporation.  This is a natural process of the wetland which facilitates feeding by some species.  The design of the wetland will include four compartments separated by bunds.  Short periods of flooding or drain down of water in these compartments could be controlled by the uPVC pipes located within each internal bund and sluice gates at the discharge point.  This will permit the rapid discharge of water when the compartments are full or following heavy rainfall events for water level control.  The area will be designed such that water can be pumped between each compartment for maintenance using pumps. 

 

Flight Path of Birds

 

2.4.19            Wetland birds fly over the northern part of the Project Area (Figure 8.4 summarises the bird flight path survey analyses), but there appear to be no regularly used flight paths which would be significantly impacted, provided careful consideration is given to the building heights, the building profile and the effects of lighting/glare effect at night of the proposed developments. 

 

2.4.20            Six storey buildings could affect the use of any existing fishponds, or those wetland habitats created on site, by foraging egrets from nearby egretries and by other species of conservation concern, particularly during winter migratory bird season.  Parts of the Project Area adjacent to off-site wetlands to the north would be unsuitable for any 6 storey buildings.

 

Existing and Proposed Hydrology

 

2.4.21            The development will not extinguish any existing flow path (including streams and channels) and the existing ditch on the perimeter of the site will be filled in order to facilitate the construction of the site formation for the proposed Development.  However, an internal drainage network underneath the future road system within the proposed development will be provided to collect the surface runoff generated within the site area. Careful consideration will be given to ensuring the overall drainage provisions and systems on site will not reduce the drainage performance of the area.

 

Nuisance from Existing Open Storage in the Northeast

 

2.4.22            The development has also taken into account the potential industrial/residential interface problem arising from the existing open storage use within the OU(CDWRA) zone which is located  immediately next to the Project Area.  Industrial noise arising from the nearby open storage operations may impose noise nuisance and other impacts. 

 

Sustainable Development

 

2.4.23            The design and construction of a development of this nature provides an ideal opportunity for the introduction of sustainable development measures.  These will be incorporated, where appropriate, into the design of the site formation works, construction process, building materials and also in the design and management of the residential and wetland areas.  The need to ensure the long term sustainability of the wetland restoration area will be a major influencing factor in this respect.

 

Continuous Public Involvement (CPI)

 

2.4.24            Wetland restoration in conjunction with development is a relatively new concept to Hong Kong.  A CPI exercise has been carried out in parallel with the EIA preparation.  This process has assisted in soliciting community and professional views, comments and suggestions at various stages in the design and data collection process.  Green groups and residents of the developments surrounding the Project Area have been consulted during the preparation of the layout options and comments have been taken into account in arriving at the preferred option.  The CPI process has been extremely useful in clarifying concerns and providing a sharing of experiences with others before selection of the preferred option.  The CPI process undertaken for this Project is described in Section 1.

 

Consideration of ‘No-development’ Option

 

2.4.25            Various factors need to be considered when contemplating the ‘No-development’ option as described in the following paragraphs.

 

2.4.26            Agricultural use is permitted as of right under the OZP, and does not require government’s approval for such use on the subject area.  This implies that the whole site could in theory be used for agricultural purposes. This would neither be ecologically sustainable, nor is it compatible with the adjacent fishponds. Agricultural use would eventually reduce the ecological value of the site and damage the ecology in the wider context of the WBA and WCA. 

 

2.4.27            According to information from the Town Planning Board (TPB) records, 64 applications have been submitted to the TPB since 2001 for permission for uses including open storage, parking area, workshop, etc. on various OU(CDWRA) zones within Yuen Long; of which 16 applications have been approved (up to June 2007).  Most of the planning applications were approved on a temporary basis for up to 3 years (Appendix B-1).  It should be noted that the existing open storage and lorry parking uses were on the Project Area before the gazettal of the OZP and are permitted to continue without a time limitation, as they have “existing use” status.

 

2.4.28            Under the statutory OZP, submission of a Wetland Restoration Area or Layout Plan is not necessarily required for applications for temporary uses.  There is no guarantee that the Project Area would be restored to its original condition or that any negative impacts would be mitigated after the interim uses are completed.  In theory the potential for such interim uses therefore presents serious environmental risks.  If the subject site remains undeveloped, similar kinds of interim uses could be present on site and their associated environmental impacts would reduce the ecological value and further degrade the ecology of the habitats.

 

2.4.29            According to the management offices of Palm Springs and Royal Palms, concerns on crime, grass fire and security of the subject site have been reported by residents of these neighbouring residential developments.  The Project Area is covered with grassland and in some parts, high grass with potential fire risk and mosquito breeding issues.  If the subject site remains in the current condition, worries about crime and trespassers through this undeveloped/vacant land to the adjacent low-rise residential buildings would continue.  Active land stewardship and regular maintenance of the Project Area is possible to reduce the risks.  However, it would and has at the same time unavoidably as a consequence, reduced the ecological value of the site by destabilising the ecological habitats. 

 

2.4.30            The above paragraphs indicate that if the Project Area remains in its current condition not only would the planning intention not be achieved but the permitted uses and possible short-term uses on site might offer potential to further degrade its ecological value and continue to pose nuisance to neighbouring developments.  The proposed residential development, with the provision of wetlands, is considered to be a desirable use of the Project Area.  It would maintain the ecological value of the Project Area on a sustainable basis, as well as providing proper site management and security measures to avoid nuisance to the surrounding areas.

 

2.4.31            The ‘no action’ alternative could therefore result in long term degradation of the Project Area and is not therefore favoured.

 

Compatible Development

 

2.4.32            Another alternative considered was to develop the Project Area in a manner similar to the adjacent development at Palm Springs and Royal Springs to the south and west of the application site.  These developments are of a form which could be described as typical for the North West New Territories. They are typically low-rise, characterised by predominantly 3 storey houses and a dense network of roads.  There is little or no variation in height profile.  The arrangement of units is typically low-rise with terraced units sitting alongside free-standing units.

 

2.4.33            This form of development has no design element which gives consideration to the ecology of the location, even though they are usually accompanied by areas of landscaping, trees planted along roads and vegetation within the private gardens.  These features are usually for ornamental and decorative landscape purposes and generally are of little ecological value.  The adjacent residential development at Palm Springs and Royal Palms was approved prior to the “Fish Pond Study” and the implementation of the Buffer Zone concept to protect and enhance the wetlands and the Mai Po Marshes.

 

2.4.34            This form of residential development therefore is not in line with the current requirements for development in the Buffer Zones and offers very little urban design/landscape and visual benefits in terms of variation of profile, permeability and landscape provision. 

 

2.4.35            It has no mitigation measures to help restore or enhance the ecology of the area.  During consultation with the Green Groups it became clear that this form of development was no longer considered acceptable within the Buffer Zone areas as there were no mitigation measures included. 

 

2.4.36            The lack of any buffer areas between the residential development and the adjacent fishponds was considered unacceptable and allowed for intrusion of human activities onto the fishpond areas.  Most fundamental was the lack of provision of any form of wetland within the Project Area.  Without any attempt to restore wetland and to encourage the use of the area by suitably selected species of birds, the traditional form of residential development did not achieve any of the ecological objectives that have now been established for the Buffer Zone areas. 

 

2.4.37            For these reasons a form of development similar to the adjacent Palm Springs and Royal Palms is considered unacceptable and this alternative was discarded.

 

2.5                    Working Up the Initial Options

 

2.5.1               It is important to note that one objective relating to the permitted development on site is “an appropriate level of residential/recreational development”.  The proposed development must also fulfil the requirements of TPB No. 12B and moreover provide ecological mitigation for the functions which will be lost as a result of the proposed development.  Therefore the ecological survey data and analyses contained within the Ecological Impact Assessment (refer to Section 8) were drivers in the layout of the development.

 

Development Criteria for Option Consideration

 

2.5.2               The statutory zoning allows flexibility in the design and layout of the buildings on the site.  The amount of development permitted is the same as the traditional form at a plot ratio of 0.4.  However, the height limit is lifted to permit up to 6 storeys and this therefore allows some scope to provide taller buildings with smaller site coverage.  This in turn allows for more of the Project Area to not be built on and scope for part of the un-built area to be used for ecological mitigation purposes. 

 

2.5.3               By considering the statutory zoning a number of options or forms of development layouts were generated for consideration.  Some of the initial forms of development included a generic ‘rectangular’ form illustrated on Figure 2.3a and a generic ‘horseshoe’ form illustrated on Figure 2.4a of residential development with associated areas of wetland.  The ‘rectangular’ form provided little relief or edge effects and basically gave only a strip of wetland to separate the residential and CA zones (Figure 2.3b). 

 

2.5.4               The concept of providing the buffer was acceptable in terms of the general concept set out in the TPB PG-No. 12B although it needed to be refined and developed to provide other component features of a well designed WRA. 

 

2.5.5               The horseshoe style of development had advantages in that it gave a longer water/residential interface (Figure 2.4b), but the concept did present some challenges in terms of providing a buffer between residential developments and the CA.  It was evident early on that the form of development needed to be refined and elaborated to accommodate the various “development criteria” which were used to develop alternatives and differentiate between options.  The Development Criteria which allow differentiation between the options are summarized in Table 2–1.

Table 21     Development Criteria

Alternative Factors Considered

Reason for Consideration

Wetland Restoration Area (WRA)

The size, layout, form of the compensation differs between the options (refer to Section 8).

Buffering between Development and Existing Ponds to the North

Minimum distance between residential developments and CA vary  (refer to Section 8)

Building Form and Location

Different building heights or mixes or layouts vary and affect performance of options (refer to Section 11)

Continuous Public Involvement (CPI)

CPI was used in the development of layouts, or in the modification of layouts following input from CPI  (refer to Section 1and 11)

Avoidance of Key Ecological Impacts

Extent and variety of compensation is a key feature as is mitigation during construction (refer to Section 8)

Adjacent Ponds

Factors include the continuity of water features

Water Supply to Wetland Features

Source of water varies

Flight Path of Birds

Use of flight path data to ascertain impacts of development on avifauna (refer to Section 8 and Figure 8.4)

Nuisance from Existing Open Storage in the Northeast

Interface issues

Sustainable Development

Opportunities for sustainable development or green building designs

 

Integrated Wetland Concept Option

 

2.5.6               Developing the theme illustrated in the “bubble diagram” and taking cognisance of the buffer zone between residential and CA, the limitations and ecological impacts arising from retention of existing wetland habitats within the Project Area, and the opportunities of a simple, sustainable yet ecologically diverse WRA, various broad ecologically sensitive layout options were considered.  Firstly, an integrated design (Option A) was derived which provided a series of residential development areas interspersed with water/wetland areas.  This layout is illustrated in Figure 2.5 and is a combination of water, roads and buildings providing for 276 houses.  Each house is large having an average floor area of 300 square metres.  This layout is relatively land intensive and shows that the areas of water are relatively narrow and that the areas of buffer between the residential development and the fishponds to the north are relatively small.  There is limited height profile variation and interest, as well as relatively limited areas of landscape reprovisioning.  The area of restored wetland is around 3.4ha for the core wetland and 1.0ha for the linear wetland areas between the development areas. 

 

2.5.7               While the shoreline between water and land is relatively long, the close proximity of the residential uses to the water would likely have a negative impact on how the wetland would operate in relation to the target bird species and would not alleviate the issues of fragmentation of wetland highlighted in Section 2.4.16.  The main disadvantage is the creation of a high site coverage and need for a large area for roads, limiting space for wetland restoration and landscaping, and the interface between residential developments, wetland restoration area and the existing fishponds adjoining the Project Area within the CA.

 

2.5.8               Furthermore, the layout does not accord with the TPB PG-No. 12B requirement to locate the residential developments as far as possible from the adjacent WCA and on that reason alone was considered to be not acceptable for further consideration.

 

Transitional Wetland Concept Options

 

2.5.9               A layout based on the conceptual design framework as established in the statutory OZP was considered as this is more likely to meet the ecological objectives.  This approach can be seen in Figure 2.2 where the concept was developed from a bubble diagram to a conceptual zoning of the Project Area and then refined to a number of options. 

 

2.5.10            Figure 2.6 illustrates the concept (Option B) of introducing wetland areas into the residential zone.  The intention was to provide compensatory habitats for species using the site such as dragonflies and butterflies and amphibians.  The concept was to provide a large area of core wetland area located to the north of the Project Area with linear wetland areas between “fingers of housing land” flowing south and protruding into the residential development.  While a priority was given to achieving a high quality of wetland mitigation, consideration was also given to achieving a high quality residential environment based upon a respectful relationship between the residential development and the wetland area.

 

2.5.11            Option B represents the medium rise form of development and has all 6 storey blocks.  36 blocks 6 storeys high are proposed.  This form of development provides the largest population with smaller units with average size of 95.8 square metres although it could also reduce population intake by having 3x duplex or 2x triplex blocks.  However, the analysis of flight paths of birds indicates that there was likely to be an adverse impact because of the height of the buildings.  These would be the only buildings of this height in the whole of the Mai Po area and in this respect visually significant.  The development has around 28% of the Project Area for wetland areas with 3.4 ha for core wetland and 2.5 ha for linear wetland areas.  Although the option offers relatively high areas of landscape reprovisioning and visual permeability, it also offers no variation in height profile and results in visual effects from relatively tall 6-storey structures on visual receivers (especially on residents in Royal Palms and Palm Springs, and on the landscape character of the Tsing Lung Tsuen Plain.

 

2.5.12            Figure 2.7 has a similar medium rise layout with streams of wetland extending within the residential area (Option C).  The width of wetland between the fingers is narrower and this may result in greater negative impact from human activities on the use of the wetland by the target species.  There is 21% of the Project Area as core wetland (around 4.3 ha), around 2.1 ha of linear wetland areas and around 44% as landscape area.  The layout has 2.5/3 storey houses along the fingers which would reduce the light glare and have less impact on the bird flight paths.  There are 4 storey buildings introduced along the boundary and some 6 storey blocks are retained in the central area away from the wetland.  This results in a gentle built-form profile consisting of 44 detached houses, 116 semi-detached houses, 164 units as four storey duplex blocks and 144 flats in 6 storey apartment bocks.  There is concern however that the location of 4 storey buildings along the boundary will have a negative impact in relation to the adjoining residential developments.

 

2.5.13            The medium rise options which included 6 storey buildings were not selected due to their visual impact on the regional landscape and the potential effect on ecology.

 

2.5.14            Figure 2.8 shows an alternative low rise option which removes all of the 6 storey buildings and has 28 2.5/3 storey detached houses, 132 semi-detached houses and 188 duplex units in 4 storey buildings (Option D).  About 19% of the Project Area is core wetland area of approximately 4.0 ha and around 10% or 2 ha are linear wetland areas.  The longer waters edge also means that more of the wetland will likely be subject to intrusion by human activities.  This option achieves some limited variation in profile and its relatively less dense layout may offer slightly reduced effects on landscape character whilst offering greater area for landscape mitigation. The possible negative impact of 4-storey development along the boundary of the adjacent residential developments also remains.

 

2.5.15            Another low rise option (Option E) shown on Figure 2.9 has the same area of wetland as Option D.  Some buildings are now only 2.5/3 storeys high along the boundaries of the Project Area adjacent to the existing residential properties with backyards directly fronting onto the proposed development in Wo Shang Wai.  The low-rise structures conform closely to the existing scale of structures in the landscape, but provide limited height profile variation and interest.  The same relationship exists between the residential buildings proposed on the Project Area to the wetland area as for Option D.  However, there is less communal open space than in Option D.

 

2.5.16            From an ecological perspective, the low rise options (Option D and E) with 2.5/3 storey houses at the centre of the Project Area are likely to have similar environmental/ecological performance. In both options, the proposed residential areas are located away from the ecological sensitive receivers i.e. fishponds in the WCA and kept close to the existing residential estates of Palm Springs and Royal Palms, leaving the proposed wetland restoration area (WRA) to encourage direct ecological linkage with the fishponds in the WCA. The reduction in building height and the reduction in number of residential units by approximately 60% and 25% respectively from the medium rise options would reduce the population of the whole development and thus reduce human activities in vicinity to the WRA. This minimization measure aims to prevent future human disturbance from the proposed residential area on the sensitive habitats offsite and also enhance the performance of the proposed wetland onsite as far as possible.

 

2.5.17            The proposed wetland of both Option D and E would contain a core area and several stream features. As a result of the discussion between different interest groups (Nature Conservation Groups, relevant Government Departments and Wetland Specialists) during Continuous Public Involvement (CPI), a further refined scheme was generated.

 

Refined Preferred Option

 

2.5.18            This option was developed after a thorough assessment of the ecological impacts and evaluation of the findings of the ecological baseline undertaken for this Project.  In addition to which several rounds of consultation with Green Groups, residents of Palm Springs and Royal Palms and discussions with Government Departments.  The modified option presented here as Option F, is the Preferred Option, and is included in Figure 2.10.

 

2.5.19            This option has discarded the “streams of water” (wetland area in between the residential houses protruding in the form of fingers) as being wetland habitat and turns them into landscaped areas.  As the interface between the residential area and wetland area has been designed out, the negative edge effect from human activities should also be minimized. The further enlargement of the WRA, the distance between the proposed residential area and the fishponds in WCA, is increased.  The potential off-site impacts could be further reduced by this design, and provide opportunity for ecological enhancement of the fishpond area.

 

2.5.20            As a result of further CPI, the length of the fingers of land has been shortened and the form of the design has been amended to create a loop in the road network and to pull the land back from the northern edge of the Project Area.  This also improves traffic circulation so that visitors who lose their way will be able to use the loop rather than having to turn in a cul-de-sac.  The effect of pulling the land back has been to increase the area of wetland to the north to 22% of the Project Area (around 4.74ha).  The landscaped area provide a visual softening and greening effect to the Project as a whole and physically link with the WRA proposed at the northern portion of the Project Area and fishponds at the north to provide aesthetical view. The 4.74ha of WRA under Option F will be in the form of freshwater marshes with reeds, freshwater ponds, trees and shrubs that provide habitats for the target species and provide a visual buffer to separate the residential development from the WCA to meet the planning intention of OU(CDWRA). A buffer planting area with trees, shrubs and groundcovers and garden fence will be included along the edge of the wetland restoration area to functionally and visually separate the residential areas and amenity areas from the wetland restoration area.

 

2.5.21            It was considered to be equally important to address the concerns of the residents in the neighbouring developments.  Other than providing a landscape buffer, greater setback of buildings and the staggered arrangement of building facades, the 4 storey blocks which are directly facing the backyard space of the adjoining 3 storey structures in Palm Springs and Royal Palms have been changed into 2.5/3 storeys buildings to minimize the “over-looking” effect.  The evolution of the various layout options were ecologically driven and environmentally oriented for improvement.  It is anticipated that the “over-looking” concerns from both the Palm Springs will be further investigated in the detailed design for the planning application submission.

 

2.5.22            The preferred option (Option F) has 127 nos. of 2.5/3 storey detached houses, 44 semi-detached houses and 180 duplex units in 4 storey buildings. It offers a balanced alternative with regard to ecology/landscape/visual criteria as well as a number of advantages over other options, namely: its reduced visual effects on adjoining residents in Palm Springs and Royal Palms as well as some variation in building profile.  The 4-storey development previously located along the southern boundary has been moved to the centre of the Project Area in this option.  The fingers of water (wetland streams) between the areas of housing have been removed and are replaced by landscape areas, resulting in an overall increase in the available area for landscape mitigation.

 

Summary of Alternatives Considered

 

2.5.23            The CPI process has therefore resulted in achieving a design and layout which maximizes the effectiveness and functionality of the wetland habitat area that is to be created on the site, by limiting adverse human interference.  It also allows for minimal impact on existing bird flight paths and results in a compatible form of residential development along the boundaries with the neighbouring sites.

 

2.5.24            The consequences of implementing the Preferred Option would therefore be the creation of an area of enhanced managed wetland in excess of the compensation required for the ecological value of the existing wetland on the site, and with a much improved carrying capacity for wildlife, and particularly for birds.  The design clearly demarcates the landscape water elements from the wetland habitat that is created.  It also creates an effective system of buffers between the residential development and the wetland habitat, and between the residential developments and the fishponds to the north. 

 

2.5.25            The approach taken in reaching this design option has been to avoid any impact on the surrounding areas if at all possible and if this could not be achieved, then the impact has been minimized. An example of this is illustrated by the location of the different house types along the boundary of the Project Area.  Any residual impact that may remain will be further offset by mitigation, such as by detailed design of the buffer space and earth bunds between the waters edge and the residential development. 

 

2.5.26            The Preferred Option has therefore provided a residential development created in the context of an ecological design.  This has included a strategy for the long term management of a newly created wetland system which will enhance the overall integrity of the Mai Po Marshes.

 

Summary of Alternative Options Considered

 

2.5.27            To summarise the discussions in the foregoing Sections Table 2–2 has included salient points which illustrate the consideration of alternatives.

Table 22     Summary of Alternative Options Considered

Development Criteria

Integrated Option

Medium Rise Option

Low Rise Option

A

B

C

D

E

F

Wetland Restoration Area (WRA) (ha)

3.4

3.4

4.3

4.0

4.0

4.7

Buffering between Development and Existing Ponds to the North (m)

little buffer distance between residential developments and the CA.

provided by discrete WRA

increased buffer zone especially in the northwest of the Site

Building Form and Location

all 2.5/3 storeys

all 6 storeys

hybrid up to 6 storeys

hybrid   2 and 4 storeys

all 2.5/3 storeys

hybrid    2.5/3 and 4 storeys

Continuous Public Involvement (CPI)

discussed as part of CPI, not forward option

discussed as part of CPI

discussed as part of CPI

discussed as part of CPI  used to develop option F

discussed as part of CPI

discussed as part of CPI process and

subsequently further refined following  further CPI process

Avoidance of Key Ecological Impact

extensive mitigation required during formation of wetland restoration area

minimisation and mitigation measures adopted

avoidance, minimisation and mitigation principles adopted

Adjacent Pond

fragmented

development

continuity provided especially with the adjacent fishponds

Water Supply to Waterscape

initially rainwater plus supplies of “top up” water such as tap water using fixed pumps and a network of pipes

rainwater only with no fixed pumps

Flight Path of Birds

consideration of birds with medium flight height but no buffer provided at the northern portion

some of the frequent flight paths may be affected by the building heights and increase disturbance 

buffer zone provided but limited width at the northwest of the Site where there are records of frequent flight paths

consideration of frequent birds flight path at low height with appropriate buffer width especially increased at northwest part of the Site

Nuisance from Existing Open Storage in the Northeast

reduced, but interface with low-rise residential units

impacts further minimized by locating non-noisy private facilities in this area.

Sustainable Development

All have opportunities to incorporate sustainable development and green building design.  However F has most sustainable solution as the WRA is wholly sustained by rainwater and not fed by alternative sources and requires no energy to maintain its functions.

 

2.6                    Construction Methods and Sequences of Works

 

Forms of construction

 

2.6.1               There are fundamentally 3 forms of construction under the development project, namely site formation, building construction and wetland restoration.  In this case, it is important to consider the types of building structures that would be suitable in the context of the statutory planning requirement and from a geotechnical perspective.

 

Site Characteristics

 

2.6.2               The Project Area is located immediately west of the Scheduled Area No.2 as delineated by Environmental, Transport and Works Bureau (ETWB) Technical Circular (Works) No. 4/2004.

 

2.6.3               Based on available ground investigation findings, marble has been found in the western portion of the Project Area.  About 2m thick fill layer is underlain by layers of marine and alluvial deposit which are mainly clay in nature.  Deep weathered metasiltstone or meta-sandstone has been envisaged in the eastern portion of the Project Area.

 

Site Formation Work

 

2.6.4               Owing to the compressible nature of the top marine and alluvial clay, the Project Area is subject to settlement which requires some engineering works to resolve the problem.

 

2.6.5               In order to accelerate the settlement process preloading in collaboration with vertical band drains may be adopted at the Project Area.  The extent of the excavation or surcharging for the sites to be selected for residential building will be subject to further engineering appraisals.

 

2.6.6               Excavated material will be utilized on site where possible for wetland restoration preloading and eventually for landscaping or disposal to a suitable facility.  Contamination testing of existing fill will be conducted to confirm, or otherwise, that the fill is inert and can be reused.  Similarly, sedimentation testing will be carried out in accordance with ETWB Technical Circular (Works) No. 34/2002.  This will identify an appropriate disposal strategy for any excavated sediment.

 

Building Construction Work

 

2.6.7               Ground investigation work has been carried out to confirm the classification of existing marble quality.  Non-percussive piling, if any is to be carried out, will need to take heed of the additional loading imposed on the marble.

 

2.6.8               On the other hand, due to the long term settlement anticipated, because of the existence of superficial marine and alluvial clay, conventional raft footing alone, resting on top of these compressible layers may impose excessive settlement to the building structures, which is not desirable.

 

2.6.9               In order to control effect on underlying marble as well as settlement consideration, box footing or pile raft supported by short piles could be the foundation schemes for some 2.5 to 3 stories houses.  For the non-marble zone, conventional Continuous Flight Augar (CFA) piles could be another foundation option for houses up to 4 stories high which include the clubhouse situated in eastern corner of the site.

 

2.6.10            The statutory zoning plan permits 6 storey dwelling.  However, it is envisaged there will be a range of 2.5/3 to 4 storey residential properties of maximum GFA 82,800m² and plot ratio 0.4.  These will be constructed in conventional cast in-situ method.  The feasibility of using pre-cast construction will be subject to further engineering appraisals.

 

Wetland Restoration

 

2.6.11            In terms of creating the wetland, it is envisaged that the wetland restoration could be formed using a clay perimeter and existing marine mud.  This would avoid exporting this material from site.  A liner is expected to be required to prevent water loss; this could be natural or artificial, the final decision will be made at the detailed design stage.  In any case a layer of soil will be laid on the bottom and sides of the wetland in order to provide suitable conditions for the establishment of the wetland.  The edges of the wetland restoration works will be formed at suitably shallow gradients to ensure they remain stable.

 

Sequence of Works

 

2.6.12            The Project Area covers approximately 21.36ha and construction is planned to be undertaken in phases as shown in Figure 2.11.

 

2.6.13            In order to protect the nearby residents and the ecological resources utilizing the adjacent fishponds as well as the Project Area per se from the disturbance of construction works (noise, movement, visual nuisance) noise barriers are proposed as shown in Figure 4.6.  The establishment of barriers/hoardings is the initial task on site and is scheduled to take place sequentially over a 6 month period.

 

2.6.14            The Wetland Restoration Area will be constructed and established under Phases A and B, shown on Appendix B-2, taking around 8 months for the excavation of the Wetland Restoration Area and profiling of the ground (refer to Appendix H for details of the shape and form of this area),  with an establishment period of at least 12 months. This establishment period will permit the wetland to be rain fed and filled, and vegetation to be planted. The hoarding between the WCA fishponds and the Wetland Restoration Area will be removed only upon completion of the site works.  However the hoarding between the Wetland Restoration Area and the construction site will remain until construction works has been completed.  This is to protect the newly created ecological resource from the effects of construction of the residential area, as described in Section 8.  The noise barriers around the perimeter of the site (for the protection of the noise sensitive human resources) will be of varying height (as described in Section 4).  This barrier may be removed in stages once the first layer of houses and protection is provided to the Project Area.

 

2.6.15            Site formation and preloading will start in Phases C and D in advance of the excavation for the wetland.  Site formation works will include excavation, filling, installation of vertical band drains and preloading works.  Once preloading works have been completed the materials will be moved from phase to phase around the site to minimize off site export or import of materials, thereby minimizing truck movements and waste of onsite resources.

 

2.6.16            Around eight months after Phases C and D commence site formation works, Phases E and F will start and follow the same construction sequencing.

 

2.6.17            Construction of substructure and superstructure work will be carried out immediately after the preloading activity for each Phase.  Overlapping of different forms of construction is expected during the whole construction period.

 

2.6.18            Raft footing supported by short piles (Pile Raft System) or box foundation is preferred for supporting the 2.5 to 3-storey houses for both marble and non-marble zone, while Continuous Flight Augar (CFA) piles will be an option to be considered for duplex-on-duplex properties.

 

2.6.19            Superstructure construction will be carried out using conventional cast-in-situ method instead of using pre-cast construction.  The feasibility of using pre-cast construction will be subject to further engineering appraisals.


3                        Air Quality

 

PREFACE

 

Wo Shang Wai to the north of Royal Palms and Palm Springs is zoned “OU(CDWRA)”.  This area comprises formed land, fish ponds filled prior to the publication of the Mai Po and Fairview Park Interim Development Permission Area (IDPA) Plan, and fragmented and partially filled marshland.  The western portion is currently mostly vacant while the eastern portion is currently partly vacant and partly occupied by a mix of uses including open storage uses, container yards and container vehicle parks.

 

The planning intention of this location is to provide incentive for the restoration of degraded wetlands adjoining existing fish ponds and to encourage the phasing out of sporadic open storage and port back-up uses on degraded wetland.  This can be achieved through comprehensive residential and/or recreational development to include wetland restoration area.  Development or redevelopment schemes on the degraded wetlands directly adjoining the existing continuous and contiguous fish ponds should include wetland restoration and buffer proposals to separate the development from and minimize its impact on the fish pond areas.  Any new building should be located farthest away from Deep Bay. (Approved Mai Po and Fairview Park OZP No. S/YL - MP/6).

 

3.1                    Summary

 

3.1.1               An air quality impact assessment has been undertaken in accordance with Section 3.9.1 of the EIA Study Brief to define the nature and scale of potential air quality impacts associated with the Project.  For this Project, major air sensitive receivers are essentially residents in nearby developments including the Mai Po San Tsuen, Royal Palms, Palm Springs and the Wo Shang Wai village.

 

3.1.2               Potential impacts associated with the construction phase have been assessed. Major sources of air quality impact include fugitive dust emissions during the excavation of pond deposits and infill materials during the foundation works, and construction of the Project and the associated infrastructure works. (i.e. roads, drains, pavements etc.). Other minor sources include emissions from vehicles using the Project Area. 

 

3.1.3               However, the Study Brief states that quantitative assessments are only required if construction dust is likely to cause exceedance. As fugitive dust impacts are expected to be minor and could be controlled by standard mitigation measures, no quantitative modelling has been undertaken to predict the fugitive dust impacts. Details of the mitigation measures and audit requirements are contained in this section.

 

3.1.4               During the operational phase, air quality impacts associated with vehicular emissions on- and off-site are considered insignificant.  Major roads like the San Tin Highway and the Castle Peak Road are some 230m away from the nearest air sensitive receivers of the Project Area, and the traffic flow on-site along access roads is also expected to be low and mainly dominated by private cars. 

 

 

 

3.1.5               As a result, vehicular emission impacts on air sensitive receivers within the proposed development should be insignificant.  There is no on-site sewage treatment plant proposed or any other sources that will contribute to odour emissions and hence no odour modelling has been undertaken.

 

3.1.6               The conclusion is that there should be no unacceptable air quality impacts associated with the implementation of this project, both during the construction and operational phases.

 

3.2                    Legislation, Standards, Guidelines and Criteria

 

3.2.1               Legislation, Standards, Guidelines and Criteria relevant to the consideration of air quality impacts under this study include the following:

 

·         Hong Kong Air Pollution Control Ordinance;

·         Air Pollution Control (Construction Dust) Regulation; and

·         Environmental Impact Assessment Ordinance and Technical Memorandum on Environmental Impact Assessment Process.

 

Hong Kong Air Pollution Control Ordinance

 

3.2.2               Hong Kong’s air quality is regulated through the Air Pollution Control Ordinance (Cap. 311) (“APCO”). The APCO specifies Air Quality Objectives (“AQOs”), which are the statutory limits for a number of pollutants and the maximum allowable number of times that these may be exceeded over specified periods – these pollutants are defined as Criteria Pollutants (“CP”). The Air Quality Objectives (AQOs) that have been defined for these pollutants (CP) are given in the following table

Table 31        Hong Kong Air Quality Objectives (mg/m3)(i)

Pollutant

1 Hour (ii)

8 Hours (iii)

24 Hours (iii)

3 Months (iv)

1 Year (iv)

Sulphur Dioxide

800

 

350

 

80

Total Suspended Particulates

500(vii)

 

260

 

80

Respirable Suspended Particulates (v)

 

 

180

 

55

Carbon Monoxide

30,000

10,000

 

 

 

Nitrogen Dioxide

300

 

150

 

80

Photochemical Oxidants (as ozone) (vi)

240

 

 

 

 

Lead

 

 

 

1.5

 

 

 

 

 

 

 

Notes:

(i)      Measured at 298K(25 oC) and 101.325 kPa (one atmosphere).

(ii)     Not to be exceeded more than three times per year.

(iii)    Not to be exceeded more than once per year.

(iv)    Yearly and three monthly figures calculated as arithmetic means.

(v)     Respirable suspended particulates means suspended particles in air with nominal aerodynamic diameter of 10 micrometres and smaller.

(vi)    Photochemical oxidants are determined by measurement of ozone only.

(vii)   This is not an AQO but a criterion for construction dust impact assessment under Annex 4 of the Technical Memorandum on Environmental Impact Assessment Process.

 

 

 

Air Pollution Control (Construction Dust) Regulation

 

3.2.3               Air Pollution Control (Construction Dust) Regulation stipulates the construction dust control requirements for both notifiable (e.g. site formation) and regulatory (e.g. road opening) works to be carried out by the Contractor.  The requirements for various notifiable and regulatory works are given in Parts 1 and 2 of the Regulation respectively.  Part 3 of the Regulation stipulates the general control requirements (e.g. site boundary and entrance) for construction dust.  The control requirements for individual activities (e.g. stockpiling of dusty material) are given in Part 4 of the Regulation. 

 

Environmental Impact Assessment Ordinance and Technical Memorandum on Environmental Impact Assessment Process

 

3.2.4               The criteria for evaluating air quality impacts are stated in Annexes 4 and 12 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM).  The EIAO-TM states that the hourly Total Suspended Particulate (TSP) level should not exceed 500mg/m3 (measured at 25oC and one atmosphere) for construction dust impact assessment   There is also a criterion for odour to meet 5 odour units based on an averaging time of 5 seconds for odour prediction assessment.

 

3.3                    Assessment Methodology

 

Construction Phase

 

3.3.1               Activities anticipated during the construction phase that could potentially give rise to fugitive dust emissions include site formation and construction of on-site infrastructure (roads/drains) and residential units. Other potential sources of air quality impacts may include exhaust emissions from construction vehicles and odour generated from the excavation of pond deposits. Para 3.9.1.4 (iii) of the EIA Study Brief states that a quantitative assessment is needed if the potential construction dust impact is likely to cause exceedance of the criteria despite incorporation of dust construction measures. 

 

Operational Phase

 

3.3.2               Potential air quality impacts could attribute to vehicular emissions from both on-site and off-site sources as well as odour sources in the vicinity. However, there will be no need for on-site sewage treatment plant as public sewer will be available shortly after completion of the development.

 

3.3.3               During the operational phase, sources of air quality impact include vehicular emissions from road traffic and on-site vehicular movements.  Para 3.9.1.4 (iv) of the EIA Study Brief states that if the assessment indicates likely exceedance of the recommended limits in the TM at the development and the nearby ASRs, a quantitative impact evaluation following the methodology in para. 3.9.1.4 (v) shall be carried out. 

 

3.3.4               As the minimum separation distance between the major roads, San Tin Highway and Castle Peak Road, and the nearest air sensitive receivers within the proposed development is more than 230m, vehicular emissions from the major roads should unlikely to affect the residential development and hence a qualitative assessment has been adopted in this Study. 

Traffic Forecast

 

3.3.5               The traffic forecast for the year 2027 (15 years after the originally planned occupation year of 2012) (both AM and PM peak hour flow) has been summarised in Table 3–2 below.  Although the occupation of the proposed residential development is now been postponed to 2013, the effect on air quality due to a further 1.95% annual increase in the flow is considered  insignificant.

 

Table 32        Traffic Forecast in Year 2027

Peak Hour Vehicle flows (veh/hr)

San Tin Highway

Castle Peak Road

Project Access Road

San Tam Road

AM

PM

AM

PM

AM

PM

AM

PM

Motor cycles

51

82

6

8

2

3

4

6

Private Car

2533

2631

226

240

88

89

162

213

Taxi

243

212

20