Laying of
Environmental Impact Assessment Report
April 2007
Mott Connell Ltd
40th floor, Hopewell Centre
183 Queen’s Road East
Wanchai
Tel: 2828 5757
Fax: 2827 1823
Chapters
1.2 The Environmental Impact
Assessment Study
1.4 Environmental Impact Assessment
Ordinance
2 CONSIDERATION OF
ALTERNATIVES
2.2 Tentative Construction Programme
2.3 Consideration of Alternative
Alignment Options
2.3.1 Physical Constraints to the Alignment
2.3.2 Routing Constraints of the Alignment
2.4 Consideration of Alternative
Construction Methods and Works Sequences
2.4.2 Submarine Pipeline Installation
2.4.4 Horizontal Directional Drilling
2.5 Selection of the Preferred Option
3 WATER QUALITY
IMPACT ASSESSMENT
3.2 Environmental Legislation,
Standards, Guidelines and Criteria
3.2.1 Environmental Impact Assessment
Ordinance (EIAO)
3.2.2 Water Quality Objectives (WQOs)
3.2.4 Hong Kong Planning Standards and
Guidelines (HKPSG)
3.2.5 Water Supplies Department (WSD) Water
Quality Criteria
3.2.7 Suspended Solids Criterion for Fish
Culture Zone
3.2.8 Suspended Solids Criterion for
Benthic Organisms
3.3 Description of the Environment
3.3.1 Marine Water Quality Monitored by EPD
3.3.3 Trend of Water Quality in Victoria
Harbour
3.5.1 Hydrodynamic and Water Quality Models
3.5.2 Sediment Plume Modelling
3.5.3 Effluent, Sewage and Surface runoff
3.6 Identification of Environmental
Impact
3.7 Prediction and Evaluation of
Environmental Impacts
3.7.2 Dissolved Oxygen, Total Inorganic
Nitrogen and Unionised Ammonia
3.7.3 Potential Contaminant Release During
Dredging
3.7.4 Hydrostatic Tests of the Water Mains
System
3.7.5 Surface Runoff, Sewage and Wastewater
from Construction Activities
3.8 Mitigation of Adverse
Environmental Impact
3.9 Evaluation of Residual Impacts
3.10 Environmental Monitoring and Audit
3.11 Conclusions and Recommendations
4 MARINE ECOLOGICAL
IMPACT ASSESSMENT
4.2 Environmental Legislation, Standards, Guidelines and Criteria
4.4 Baseline Conditions & Marine
Ecological Sensitive Receivers
4.4.1 Existing Condition of Victoria
Harbour
4.6 Identification and Prediction of
Environmental Impacts
4.7 Evaluation of Environmental
Impacts
4.8 Mitigation of Adverse
Environmental Impact
4.9 Evaluation of Residual Impacts
4.10 Environmental Monitoring and Audit
4.11 Conclusions and Recommendations
5.2 Environmental Legislation,
Standards, Guidelines and Criteria
5.2.2 Area Sensitivity Ratings
5.4.2 Area Sensitive Ratings (ASRs)
5.4.3 Assessment for the Project
5.5 Identification, Prediction and
Evaluation of Environmental Impacts
5.5.3 Evaluation of Noise Impact
5.6 Mitigation of Adverse
Environmental Impacts
5.6.1 Work Schedule Rearrangement
5.7 Evaluation of Residual Impacts
5.8 Environmental Monitoring and
Audit
5.9 Conclusions and Recommendations
6.2 Environmental Legislation,
Standards, Guidelines and Criteria
6.2.3 Construction and Demolition (C&D)
Materials
6.3.2 Marine Site Investigation
6.4 Baseline Condition of Marine
Dredged Sediment
6.5 Identification and Evaluation of
Environmental Impacts
6.6 Mitigation of Adverse
Environmental Impacts
6.6.2 Waste Reduction Measures
6.7 Evaluation of Residual Impacts
6.8 Environmental Monitoring and
Audit
6.9 Conclusions and Recommendations
7 AIR QUALITY IMPACT
ASSESSMENT
7.2 Environmental Legislation,
Standards, Guidelines and Criteria
7.2.1 Hong Kong Air Pollution Control
Ordinance
7.2.2 Air Pollution Control (Construction
Dust) Regulation
7.2.3 Technical Memorandum on EIA Process
(EIAO-TM), Annex 4 and 12
7.3 Baseline Conditions & Air
Sensitive Receivers
7.4 Identification and Evaluation of
Air Quality Impacts
7.5 Mitigation of Adverse
Environmental Impacts
7.6 Evaluation of Residual Air
Quality Impacts
7.7 Environmental Monitoring and
Audit
7.8 Conclusions and Recommendations
8 CULTURAL HERITAGE
IMPACT ASSESSMENT
8.2 Environmental Legislation,
Standards, Guidelines and Criteria
8.2.1 Technical Memorandum on the EIA
Process, Annex 10 and 19
8.2.2 Antiquities and Monuments Ordinance
(Cap.53)
8.2.3 Hong Kong Planning Standards and
Guidelines
8.2.4 Marine Archaeological Guidelines
8.3 Cultural Heritage Impact
Assessment Methodology
8.3.3 Establishing Archaeological Potential
8.5 Identification of Cultural
Heritage Impact
8.6 Assessment of Cultural Heritage
Impact
8.7 Mitigation of Adverse
Environmental Impact
8.8 Evaluation of Residual Cultural
Heritage Impact
8.9 Environmental Monitoring and
Audit
8.10 Conclusions and Recommendations
9.2 Environmental Legislation,
Standards, Guidelines and Criteria
9.3 Fisheries Impact Assessment
Methodology
9.5 Identification of Fisheries
Impacts
9.6 Assessment of Fisheries Impacts
9.7 Mitigation of Adverse
Environmental Impacts
9.8 Evaluation of Residual Fisheries
Impacts
9.9 Environmental Monitoring &
Audit
9.10 Conclusions and Recommendations
10 SUMMARY OF
ENVIRONMENTAL OUTCOMES
10.1 Population and Environmental
Sensitive Areas Protected
10.2 Environmental Friendly Designs
Recommended and Problems Avoided
10.3 Environmental Benefits of the
Project
11 ENVIRONMENTAL
MONITORING AND AUDIT (EM&A) REQUIREMENTS
12 CONCLUSIONS AND
RECOMMENDATIONS
List of Tables
Table 3‑1.... Summary of Water Quality Objectives for the Victoria
Harbour WCZ
Table 3‑2.... Summary of Water Quality Objectives for the Western
Buffer WCZ
Table 3‑3.... WSD’s Water Quality Criteria for Flushing Water at Sea
Water Intakes
Table 3‑5.... Water Quality Indicator Points
Table 3‑6.... Summary of Parameters for Sediment Plume Model
(Delft3D-WAQ)
Table 3‑7.... Sediment Quality near the Dredging Area
Table 3‑8.... Specifications for General Fill Material and Granular
Fill Material
Table 3‑9.... Depth-averaged and Surface SS levels near the Dredging
Area
Table 3‑10.. DO, TIN and NH3-N levels near
the Dredging Area
Table 3‑11.. Predicted Suspended Solids Elevations at Marine
Ecology Sensitive Receivers
Table 3‑12.. Predicted Suspended Solids Concentrations at Marine
Ecology Sensitive Receivers
Table 3‑13.. Predicted Suspended Solids Elevations at Cooling and
Sea Water Intakes
Table 3‑14.. Predicted Suspended Solids Concentrations at Cooling
and Sea Water Intakes
Table 3‑15.. Predicted Dissolved Oxygen, Total Inorganic Nitrogen
and Unionised Ammonia Elevations
Table 3‑17.. Comparison of Marine Sediment Elutriate Test Results
with Water Quality Standards
Table 4‑3.... Benthic Epifauna Recorded around Green Island (Source:
ERM, 1995)
Table 4‑5.... Evaluation of the Ecological Importance of the
Inter-tidal Habitats
Table 4‑6.... Evaluation of the Ecological Importance of the
Sub-tidal Habitats
Table 4‑7.... Evaluation of the Significance of Ecological Impact
Table 5‑2.... Basic Noise Levels (BNL, Leq.30 min dB(A))
Table 5‑3.... Representative Noise Sensitive Receivers
Table 5‑4.... Noise Emission Inventory (Sai Ying Pun)
Table 5‑5.... Noise Emission Inventory (West Kowloon)
Table 5‑6.... Selected NSRs for Noise Assessment
Table 5‑7.... Summary of Unmitigated Construction Noise Levels during
Normal Daytime Working Hours
Table 5‑8.... Summary of Unmitigated Construction Noise Levels from
dredging during Restricted Hours
Table 6‑1.... Coordinates, Type and Depth of Vibrocores
Table 6‑2.... Sample Arrangement for Chemical Testing
Table 6‑3.... Testing Methods and Reporting Limits for Metals and
Metalloids Analysis
Table 6‑4.... Testing Methods and Reporting Limits for TBT, PAHs and
PCBs Analysis
Table 6‑5.... Sediment Quality Criteria for the Classification of
Sediment
Table 6‑6.... Composite Sample Arrangement for Biological Testing
Table 6‑7.... Test Species for Biological Testing
Table 6‑8.... Test endpoints and decision criteria for biological
testing
Table 6‑9.... Contaminant Levels of Vibrocore Samples and Their
Categories
Table 6‑10.. Summary of Classification of Vibrocore Samples
Table 6‑11.. Summary of Ancillary Tests Results
Table 6‑12.. Summary of Toxicity Test Failure
Table 6‑13.. Summary of Waste Handling Procedures and Disposal
Routes
Table 7‑1.... Hong Kong Air Quality Objectives (mg/m3)(i)
Table 7‑2.... Background Air Quality (2001 – 2005)
Table 7‑3.... Representative Air Sensitive Receivers
Table 9‑2.... Fisheries Production Values from each AFCD Fishing
Zone within the Study Area
List of Figures
Figure 1.1 Indicative Route of the Proposed Watermains
Figure 2.1 Physical Constraints to the Proposed Submarine Watermain
Figure 2.2 Selected Route of Proposed Submarine Watermain
Figure 2.3 Plan View, Profile and Cross Section of Proposed Submarine Watermain
Figure 2.4 Bottom Pull Method
Figure 2.5 Lay Barge Method
Figure 2.6 Float and Sink Method
Figure 2.7 Horizontal Directional Drilling (HDD) Method
Figure 3.2 Locations of Water Sensitive Receivers and Stormwater Outfalls at Western Harbour
Figure 3.3 Extent of the Western Harbour Model Grid
Figure 3.4 Details of the Western Harbour Model Grid in the Project Area
Figure 3.5 Resolution of the Western Harbour Model Grid
Figure 3.6 Grid Refinement of the Western Harbour Model Grid
Figure 3.7a Coastline Configuration in the Project Area
Figure 3.7b Coastline Configuration in the Victoria Harbour
Figure 3.7c Coastline Configuration in the vicinity of the Alignment
Figure 3.8a Bathymetry in the Project Area
Figure 3.8b Bathymetry in the Victoria Harbour
Figure 3.8c Bathymetry in the vicinity of the Alignment
Figure 3.9 Typical Configuration of Silt Curtain and Silt Screen
Figure 4.1 Study Area and Sampling Locations for Marine Ecological Impact Assessment
Figure 4.2 Intertidal Habitats within the Study Area
Figure 5.1 Locations of Noise Sensitive Receivers in Sai Ying Pun
Figure 5.2 Locations of Noise Sensitive Receivers in West Kowloon
Figure 5.3 Works Area – Sai Ying Pun
Figure 5.4 Works Area – West Kowloon
Figure 5.5 Location of Night-time Dredging Zone
Figure 6.1 Longitudinal Geological Profile of Proposed Submarine Watermain Alignment
Figure 6.2 Locations of Vibrocores
Figure 6.3 Sediment Classification Plan
Figure 7.1 Locations of Air Quality Sensitive Receivers in Sai Ying Pun
Figure 8.1 Geophysical Survey Area and Seabed Features with Side Scan Sonar Track
Figure 9.1 Location of AFCD Fishing Zones in the vicinity of the Proposed Watermains
Figure 9.2 Fishing Grids within the Study Area
List of Appendices
Appendix A EIA Study Brief No. ESB-132/2005
Appendix B Tentative Project Programme
Appendix C1 Water Quality Modelling Results
Appendix C2 Laboratory Test Report on Elutriate Tests
Appendix D Not Used
Appendix E Detailed Calculations of Construction Noise Levels
Appendix F2 Laboratory Test Report on Chemical Screening
Appendix F3 Laboratory Test Report on Biological Screening
Appendix F4 Approval Letter from MFC on Dredging Rationale
Appendix G Not Used
Appendix H Marine Archaeological Investigation Report
In February 2006,
Mott Connell Limited (MCL) was commissioned by Water Supplies Department under
Agreement No. CE 42/2005(WS) to carry out the investigation and preliminary
design for the “Laying of Western Cross Harbour Main and Associated Land Mains
from West Kowloon to Sai Ying Pun” (The Project).
The need for the
project has evolved from the requirement to provide security of water supply
between
As cross-harbour
pipelines are strategically important, it is necessary to lay a new
cross-harbour pipeline on the western part of the harbour for maintaining the
reliability of cross-harbour water transfer to
The primary
objective of this Assignment is to study the feasibility of providing laying of
this additional submarine watermain and associated land mains. The Project and
the Environmental Impact Assessment (EIA) is charged with identifying
alternative sites and alignments if necessary as part of the EIA study for the
Project, and obtaining an Environmental Permit (EP). This Assignment requires
preliminary designs, contract strategy, programmes and cost estimates to be
prepared to enable the detailed design to proceed. This Environmental Impact
Assessment (EIA) Report is a key milestone of the Assignment and has been
prepared in conjunction with other design teams.
The route of the proposed watermains is shown in Figure 1.1. The proposed Project is to construct and operate a new western cross harbour main and associated land mains.
The scope of the
proposed Project comprises the following:
(i) approximately 2100-metre section of
1200mm nominal diameter of submarine watermain across Victoria Harbour from its
connection at Lin Cheung Road in West Kowloon to the existing Sai Ying Pun
Fresh Water Pumping Station in Sheung Wan (a designated project under EIA
Ordinance);
(ii)
approximately
2200-metre section of 1200mm nominal diameter of associated land watermains
(Not a designated project under EIA Ordinance).
1.2 The Environmental Impact Assessment Study
The submarine watermain component (referred in Section 1.1(i) above) of
the Project is a Designated Project under Schedule 2, Part 1(E3) of the
Environmental Impact Assessment Ordinance (EIAO) (Cap. 499) and an
Environmental Permit (EP) issued under the EIAO is required for the
construction and operation of the designated project. An application
(No. ESB-132/2005) for a EIA study brief under section 5(7)(a) of the EIAO was
submitted by Water Supplies Department on
The purpose of the EIA study is to provide information on the nature and extent of environmental impacts arising from the construction of the proposed designated project and related activities taking place concurrently, ultimately providing information on the following:
(i) the overall acceptability of any adverse
environmental consequences that are likely to arise as a result of the proposed
project;
(ii) the conditions and requirements for the
detailed design, construction and operation of the proposed project to
mitigate against adverse environmental consequences wherever practicable; and
(iii) the acceptability of residual impacts after the proposed
mitigation measures are implemented.
The scope of the EIA covers the Project proposed in the Project Profile and the works and facilities mentioned in Section 1.1 above. The EIA study addresses the key issues described below, together with any other key issues identified during the course of the EIA study and the cumulative environmental impacts of the Project, through interaction or in combination with other existing, committed, and planned and known potential developments in the vicinity of the Project:
(i) the potential water quality and marine
ecology impacts arising from the dredging, laying of pipe and backfilling works
for the construction of the submarine watermain.
(ii) the potential noise and dust impacts
arising from the construction works of the Project.
(iii) the potential impacts on sites of cultural
heritage of marine archaeological deposit likely to be affected by the
construction works of the Project.
(iv) the potential fisheries impact arising from the
Project.
The EIA study addressed all environmental aspects of the activities and has been based on the best and latest information available during the course of the EIA study. The cumulative environmental impacts from the Project with other interacting projects were assessed, including details of the construction programme and methodologies.
Previously approved studies or EIA reports which are relevant to the Project were reviewed and relevant information extracted for the purpose of this EIA study. The following study or EIA report has been referred to:
·
Proposed Submarine Gas Pipelines from Cheng Tou
Jiao Liquefied Natural Gas Production Plant,
The proposed Project covers three main areas, namely:
The works for
The works in
In Sai Ying Pun (Not
a designated project under EIA Ordinance), the works comprise Sai Ying
Pun area adjacent to Western Wholesale Food Market and is bounded by the
approaches of Western Harbour Crossing Interchange. The proposed 1200mm diameter fresh watermain
will be laid in this portion for connection to the existing Sai Ying Pun Fresh
Water Pumping Station situated at the junction of
This EIA report covers the designated project component of the Project.
1.4 Environmental Impact Assessment Ordinance
As detailed in
Section 1.2, the proposed submarine watermain is a Designated Project under
Schedule 2, Part1(E3) of the EIAO (Cap. 499) and an EP issued under the EIAO is
required for the construction and operation of the designated project.
To apply for an
EP, an EIA must be undertaken in accordance with the requirements of the Study
Brief issued by EPD on 13 October 2005, under reference No. ESB-132/2005.
Reference can be made to the full requirements of the Study Brief which is contained
in Appendix A.
The EIA has been
conducted in accordance with the Study Brief, the Project Profile (No.
PP-258/2005) and the criteria in the relevant sections of the Technical
Memorandum on the EIA Process (Environmental Impact Assessment Ordinance)
(EIAO-TM). The EIA has identified, described, predicted and evaluated potential
environmental impacts, mitigation measures and will consider the impacts of any
feasible alternatives.
The EIA Study
assessed and discussed the alternative alignments and landing points of the
proposed submarine watermain, alternative construction methods and sequences,
and to compare their environmental benefits and dis-benefits with the view of
selecting the preferred options from the environmental perspective.
The
objectives of the EIA Study as detailed in the EIA Study Brief are as follows:
(i) to describe the Project and associated works
together with the requirements for carrying out the Project;
(ii) to identify if there are other types of
Designated Projects under Part I Schedule 2 of the EIAO to be covered in the
Project;
(iii) to consider alternative alignment(s) and
landing points of the submarine watermain, alternative construction method(s)
and sequence(s), and to compare their environmental benefits and dis-benefits
with the view of selecting the preferred options from the environmental
perspective;
(iv) to identify and describe the elements of the
community and environment likely to be affected by the proposed project and/or
likely to cause adverse impacts to the proposed project, including both the
natural and man-made environment;
(v) to identify and quantify emission sources
and determine the significance of impacts on sensitive receivers and potential
affected uses;
(vi) to identify and quantify any potential losses
or damage to flora, fauna and natural habitats and to propose measures to
mitigate these impacts;
(vii) to identify any negative impacts on fisheries
and to propose measures to mitigate these impacts;