Table of contents

1 INTRODUCTION.. 1-1

1.1 Background. 1-1

1.2 Objectives of the EIA Study. 1-2

1.3 Structure of EIA Report 1-3

2 project descriptions. 2-1

2.1 Project Scope. 2-1

2.2 Need of the Project 2-1

2.3 Consideration of Alternative Design and Layout 2-2

2.4 Consideration of Alternative Construction Methods. 2-12

2.5 Consideration of Alternative Work Sequences. 2-15

2.6 Selection of Preferred Scenario. 2-15

2.7 Details of Selected Construction Methods. 2-17

2.8 Public Consultation. 2-18

2.9 Concurrent Projects. 2-21

2.10 Environmental Benefits. 2-21

3 Air Quality Impact Assessment.. 3-1

3.1 Introduction. 3-1

3.2 Environmental Legislation, Standards and Guidelines. 3-1

3.3 Baseline Environmental Condition. 3-2

3.4 Air Sensitive Receivers. 3-3

3.5 Identification of Pollution Sources. 3-4

3.6 Assessment Methodology. 3-6

3.7 Prediction of Odour Impact 3-7

3.8 Mitigation Measures. 3-8

3.9 Residual Impact 3-10

3.10 Environmental Monitoring and Audit Requirements. 3-10

3.11 Conclusion. 3-11

4 Noise Impact Assessment.. 4-1

4.1 Introduction. 4-1

4.2 Environmental Legislation, Standards and Guidelines. 4-1

4.3 Descriptions of Environment 4-6

4.4 Identification of Potential Noise Impact 4-6

4.5 Noise Sensitive Receivers. 4-6

4.6 Assessment Methodology, Prediction and Evaluation of Environmental Impacts. 4-7

4.7 Evaluation and Recommendation of Noise Mitigation Measures. 4-16

4.8 Evaluation of Residual Impacts. 4-20

4.9 Environmental Monitoring and Audit Requirements. 4-20

4.10 Conclusion. 4-21

5 Water Quality Impact Assessment.. 5-1

5.1 Introduction. 5-1

5.2 Environmental Legislation, Standards and Guidelines. 5-1

5.3 Description of the Environment 5-4

5.4 Identification of Water Quality Impact 5-10

5.5 Water Sensitive Receivers. 5-13

5.6 Assessment Methodology. 5-14

5.7 Impact Prediction and Assessment 5-17

5.8 Water Quality Mitigation Measures. 5-22

5.9 Evaluation of Residual Impacts. 5-25

5.10 Environmental Monitoring and Audit Requirements. 5-25

5.11 Conclusion. 5-26

6 Terrestrial Ecological Impact Assessment.. 6-1

6.1 Introduction. 6-1

6.2 Relevant Legislations, Standards & Guidelines. 6-1

6.3 Study Area & Ecological Sensitive Receivers. 6-2

6.4 Literature Review.. 6-3

6.5 Evaluation of Past Information & Identification of Data Gap. 6-5

6.6 Methodology for Terrestrial & Freshwater Surveys. 6-5

6.7 Survey Results – Habitats & Vegetation. 6-7

6.8 Survey Results – Fauna. 6-13

6.9 Evaluation of Habitat 6-17

6.10 Identification of Ecological Impacts. 6-21

6.11 Evaluation of Ecological Impacts. 6-24

6.12 Recommendations & Mitigation Measures. 6-29

6.13 Evaluation of Residual Impacts. 6-30

6.14 Environmental Monitoring and Audit Programme. 6-30

6.15 Conclusion. 6-31

6.16 References. 6-32

7 Marine Ecological Impact Assessment.. 7-1

7.1 Introduction. 7-1

7.2 Relevant Legislations, Standards & Guidelines. 7-1

7.3 Study Area. 7-2

7.4 Literature Review.. 7-2

7.5 Evaluation of Past Information & Identification of Data Gap. 7-3

7.6 Methodology for Intertidal Survey. 7-3

7.7 Methodology for Fish Survey. 7-5

7.8 Methodology for Benthic Survey (REA) 7-5

7.9 Methodology for Benthic Survey (Grab Sampling) 7-6

7.10 Results of Intertidal Survey. 7-9

7.11 Results of Fish Survey. 7-11

7.12 Results of Benthic Survey (REA) 7-11

7.13 Results of Benthic Survey (Grab Sampling) 7-12

7.14 Evaluation of Habitat 7-13

7.15 Impact Identification and Assessment 7-14

7.16 Evaluation of Ecological Impacts. 7-18

7.17 Recommendations & Mitigation Measures. 7-20

7.18 Evaluation of Residual Impacts. 7-20

7.19 Environmental Monitoring and Audit Programme. 7-21

7.20 Conclusion. 7-21

7.21 References. 7-22

8 Fisheries Impact Assessment.. 8-1

8.1 Introduction. 8-1

8.2 Relevant Legislations, Standards & Guidelines. 8-1

8.3 Study Area and Sensitive Receivers. 8-1

8.4 Study Methodology. 8-1

8.5 Description of the Environment & Baseline Fisheries Information. 8-2

8.6 Impact Identification and Assessment 8-5

8.7 Impact Evaluation. 8-9

8.8 Recommendations & Mitigation Measures. 8-10

8.9 Residual Impact 8-10

8.10 Environmental Monitoring and Audit Programme. 8-10

8.11 Conclusion. 8-10

8.12 References. 8-11

9 Waste Management implications. 9-1 & Land contamination

9.1 Introduction. 9-1

9.2 Relevant Legislations, Standards & Guidelines. 9-1

9.3 Assessment Methodology. 9-3

9.4 Estimation of Construction Waste Generation and Evaluation of Impact
(Land-based Works) 9-5

9.5 Estimation of Construction Waste Generation and Evaluation of Impact
(Marine-based Works) 9-9

9.6 Land Contamination. 9-10

9.7 Estimation of Operational Phase Waste Generation and Evaluation of Impact 9-12

9.8 Mitigation Measures. 9-12

9.9 Residual Impact 9-16

9.10 Environmental Monitoring and Audit 9-16

9.11 Conclusion. 9-16

10 Landscape and Visual Impact.. 10-1

10.1 Introduction. 10-1

10.2 Landscape and Visual Legislation, Standards and Guidelines. 10-1

10.3 Scope and Content of Study. 10-5

10.4 Landscape and Visual Impact Assessment Methodology. 10-6

10.5 Baseline Conditions. 10-15

10.6 Landscape Impact Assessment 10-28

10.7 Visual Impact Assessment 10-43

10.8 Cumulative Impacts. 10-60

10.9 Environmental Monitoring and Audit 10-60

10.10 Conclusion. 10-61

11 Built Heritage Impact Assessment.. 11-1

11.1 Introduction. 11-1

11.2 Environmental Legislations, Standards and Guidelines. 11-1

11.3 Assessment Methodology. 11-3

11.4 Baseline Condition. 11-5

11.5 Evaluation of Potential Impact on Built Heritage Resources. 11-7

11.6 Mitigation Measures. 11-9

11.7 Evaluation of Residual Impact 11-12

11.8 Environmental Monitoring and Audit 11-12

11.9 Conclusion. 11-12

11.10 Bibliography. 11-13

12 ENVIRONMENGTAL MONITORING & AUDIT REQUIREMENTs. 12-1

12.1 Introduction. 12-1

12.2 Air Quality. 12-1

12.3 Noise. 12-1

12.4 Water Quality. 12-2

12.5 Terrestrial Ecology. 12-2

12.6 Marine Ecology. 12-2

12.7 Fisheries. 12-3

12.8 Waste Management 12-3

12.9 Landscape and Visual 12-3

12.10 Built Heritage. 12-4

13 environmental outcomes. 13-1

13.1 Environmental Designs Recommended and Environmentally Friendly Options Considered 13-1

13.2 Key Environmental Problems Avoided. 13-3

14 Conculsion.. 14-1

14.1 Introduction. 14-1

14.2 Air Quality. 14-1

14.3 Noise. 14-1

14.4 Water Quality. 14-2

14.5 Terrestrial Ecology. 14-3

14.6 Marine Ecology. 14-3

14.7 Fisheries. 14-4

14.8 Waste Management 14-4

14.9 Landscape and Visual 14-5

14.10 Built Heritage. 14-5

14.11 EM&A Requirement 14-6

14.12 Overall Conclusion. 14-6

15 Implementation Schedule of Recommended Mitigation Measures 15-1

List of Tables

Table 2-1 Summary of Site Selection Process for Sewage Treatment Plant

Table 2-2 Summary of Site Selection Process for Diffuser

Table 2-3 Tanker Away Arrangement

Table 2-4 Summary of Selection Process for Construction Works of Submarine Outfall

Table 2-5 Summary of Selection Process for Construction Works of Diffuser

Table 2-6 Summary of Preferred Scenario

Table 2-7 Summary of Environmental Concerns with Solutions

Table 3-1 Hong Kong Air Quality Objectives

Table 3-2 Annual Average Concentration of Pollutants from Year 2010 to 2014 at EPD’s Air Quality Monitoring Station (Tap Mun)

Table 3-3 Representative Air Sensitive Receivers

Table 3-4 Summary of Conversion Factors from 1-hour to 5-second

Table 3-5 Design Parameter of the Sewage Treatment Plant

Table 3-6 Maximum 5-second Odour Levels for ASRs

Table 4-1 Construction Noise Standards during Non-Restricted Hours

Table 4-2 Construction Noise Standards during Restricted Hours

Table 4-3 Area Sensitivity Ratings (ASRs)

Table 4-4 Ground-borne Construction Noise Limits

Table 4-5 Acceptable Noise Levels

Table 4-6 Background Noise Monitoring Results at Selected NSRs in Po Toi O

Table 4-7 Acceptable Noise Levels (ANLs) during Operational Period

Table 4-8 Representative Noise Sensitive Receivers

Table 4-9 Typical PME to be used for Construction of Sewage Treatment Plant

Table 4-10 Typical PME to be used for Installation of Rising Mains (Trenchless Method)

Table 4-11 Typical PME to be used for Installation of Gravity Sewers and Rising Mains (Open Cut Method)

Table 4-12 Typical PME to be used for Installation of Gravity Sewers on Po Toi O Chuen Road (Open Cut Method)

Table 4-13 Typical PME to be used for Construction of Submarine Outfall (Land-based Works)

Table 4-14 Predicted Worst-case Cumulative Construction Noise Levels at Representative NSRs - Unmitigated Scenario

Table 4-15 Typical Noisy Equipment for the Proposed Po Toi O Sewage Treatment Plant

Table 4-16 Proposed Design Measures For Operation of Po Toi O Sewage Treatment Plant

Table 4-17 Predicted Worst-case Operation Noise Levels at Representative NSRs - Unmitigated Scenario

Table 4-18 Quiet PME and Associated Sound Power Level Proposed for the Project

Table 4-19 Predicted Cumulative Construction Noise Levels at Representative NSRs - Mitigated Scenario

Table 5-1 Summary of Water Quality Objectives for Port Shelter WCZ

Table 5-2 Standards for Effluents Discharged into the Coastal Waters of Tolo and Port Shelter Water Control Zones

Table 5-3 Water Quality Monitoring Results at MM19 from 2009 to 2013

Table 5-4 Beach Water Quality Monitoring Results at Clear Water Bay First Beach from 2009 to 2013

Table 5-5 Beach Water Quality Monitoring Results at Clear Water Bay Second Beach from 2009 to 2013

Table 5-6 Water Quality Sampling Stations

Table 5-7 Summary of the Monitoring Data for Dry Season

Table 5-8 Summary of the Monitoring Data for Wet Season

Table 5-9 Tanker Away Arrangement

Table 6-1 Conservation Statuses of Birds with Conservation Importance and with Breeding Record in the Study Area

Table 6-2 Conservation Statuses of Plants with Conservation Importance Recorded in the Study Area

Table 6-3 Conservation Statuses of Birds with Conservation Importance Recorded in the Study Area

Table 6-4 Ecological Value of Shrubland

Table 6-5 Ecological Value of Woodland

Table 6-6 Ecological Value of Developed Area

Table 6-7 Ecological Value of Grassland

Table 6-8 Ecological Value of Watercourses W1, W2 & W3

Table 6-9 Ecological Value of Rocky Shore (Above High Tide Level)

Table 6-10 Summary of Habitat Loss

Table 6-11 Evaluation of the Significance of Ecological Impact on Shrubland

Table 6-12 Evaluation of the Significance of Ecological Impact on Woodland

Table 6-13 Evaluation of the Significance of Ecological Impact on Developed Area

Table 6-14 Evaluation of the Significance of Ecological Impact on Grassland

Table 6-15 Evaluation of the Significance of Ecological Impact on Watercourses W1, W2 & W3

Table 6-16 Evaluation of the Significance of Ecological Impact on Rocky Shore (Above High Tide Level)

Table 7-1 Weather Condition during Each Intertidal Survey

Table 7-2 Categories of (a) Benthic Attributes, (b) Ordinal Ranks of Percentage Cover, and (c) Ordinal Ranks of Taxa Abundance of Substrate

Table 7-3 Conservation Statuses of Taxa with Conservation Importance Recorded on Rocky Shore

Table 7-4 Conservation Statuses of Taxa with Conservation Importance Recorded on Mudflat

Table 7-5 Ecological Value of Intertidal Zones within 500 m from the Project

Table 7-6 Ecological Value of Subtidal Habitats

Table 7-7 Tanker Away Arrangement

Table 7-8 Evaluation of the Significance of Ecological Impact on Intertidal Zones within 500 m from the Project

Table 7-9 Evaluation of the Significance of Ecological Impact on Subtidal Habitats

Table 8-1 Vessel Number, Relative Abundance, Productivity (Adult Fish) and Relative Productivity (Adult Fish) among Hong Kong Waters of Each Vessel Type Operating near Po Toi O

Table 8-2 Production Composition of the Top 10 Families from Capture Fisheries in the Study Area

Table 8-3 Tanker Away Arrangement

Table 8-4 Evaluation of the Significance of Impacts on Fisheries

Table 9-1 Sediment Quality Criteria for the Classification of Sediment

Table 9-2 Summary of Land-based Waste

Table 9-3 Sediment Quality at Station PS6

Table 9-4 Summary of Sediment Sampling and Testing Results

Table 9-5 Historical Change in Po Toi O and its vicinity

Table 10-1 Relationship between Receptor Sensitivity and Magnitude of Change in Defining Impact Significance

Table 10-2 Landscape Resources

Table 10-3 Landscape Character Areas

Table 10-4 Key Visually Sensitive Receivers (VSRs)

Table 10-5 Magnitude of Landscape Change during the Construction and Operation Phases before Mitigation

Table 10-6 Proposed Construction Phase Landscape and Visual Mitigation Measures

Table 10-7 Proposed Operation Phase Landscape and Visual Mitigation Measures

Table 10-8 Significance of Landscape Impacts in Construction and Operation Phases (Adverse Impacts unless otherwise stated)

Table 10-9 Magnitude of Visual Change during the Construction and Operation Phases before Mitigation

Table 10-10 Significance of Visual Impacts in the Construction and Operation Phases

Table 11-1 Summary of Identified Built Heritage Resources in the Built Heritage Impact Assessment Study Area

Table 11-2 Brief Information of the Identified Built Heritage Resources

Table 11-3 Impact Assessment in Construction Stage

Table 11-4 Mitigation Measures in Construction Stage

Table 13-1 Key Environmental Problems Avoided/Minimized

lIST OF FIGUREs

Figure 1-1 Layout Plan of Proposed Sewerage Works in Po Toi O

Figure 2-1 Location of Different Sewage Treatment Plant Options

Figure 2-2 Location of Different Diffuser Options

Figure 3-1 Location of Air Sensitive Receivers

Figure 3-2 Contours of 5-Second Odour Levels in OUm^-3 at 1.5 m above ground

Figure 3-3 Contours of 5-Second Odour Levels in OUm^-3 at 4.5 m above ground

Figure 3-4 Contours of 5-Second Odour Levels in OUm^-3 at 7.5 m above ground

Figure 4-1 Location of Baseline Noise Monitoring Stations

Figure 4-2 Location of Noise Sensitive Receivers

Figure 5-1 Location of Water Sampling Stations

Figure 5-2 Locations of Water Sensitive Receivers

Figure 5-3 Study Area of Water Quality

Figure 6-1 Terrestrial Ecology Survey Plan

Figure 6-2 Habitat Map

Figure 6-3 Locations of Species with Conservation Importance

Figure 7-1 Marine Ecology Survey Plan

Figure 7-2 Rapid Ecological Assessment (REA) Survey Plan

Figure 8-1 Locations of Artificial Reefs

Figure 8-2 Location of Po Toi O Fish Culture Zone

Figure 8-3 Photographic Record of Po Toi O Fish Culture Zone

Figure 9-1 Location of PS6 and Dredging Location

Figure 9-2 Cofferdam and Sediment Sampling Location

Figure 10.1 Landscape Study Area

Figure 10.2 Review of Planning Framework

Figure 10.3a Landscape Resources (1 of 3)

Figure 10.3b Landscape Resources (2 of 3)

Figure 10.4 Landscape Resources (3 of 3)

Figure 10.5a Landscape Character Areas (1 of 2)

Figure 10.5b Landscape Character Areas (2 of 2)

Figure 10.6.1 Landscape Resources Photographs (1 of 2)

Figure 10.6.2 Landscape Resources Photographs (2 of 2)

Figure 10.7 Landscape Character Area Photographs

Figure 10.8.1 Key Visual Elements

Figure 10.8.2 View Corridor Photographs

Figure 10.8.3 Residential VSR Photographs

Figure 10.8.4 Recreational VSR Photographs (1 of 2)

Figure 10.8.5 Recreational VSR Photographs (2 of 2)

Figure 10.8.6 Travelling VSR Photographs

Figure 10.8.7 Occupational VSR Photographs

Figure 10.9 Zone of Visual Influence (ZVI) and Visually Sensitive Receivers (VSRs) during Construction Phase

Figure 10.10 Zone of Visual Influence (ZVI) and Visually Sensitive Receivers (VSRs) during Operation Phase

Figure 10.11 Residual Impacts on Landscape Resources with Mitigation at Year 10

Figure 10.12 Residual Impacts on Landscape Character Areas with Mitigation at Year 10

Figure 10.13 Residual Impacts on Visually Sensitive Receivers (VSRs) with Mitigation at Year 10

Figure 10.14 Photomontage Viewpoint 1 from Po Toi O Chuen Road looking South

Figure 10.15 Photomontage Viewpoint 2 from Tai Au Mun Road looking East

Figure 10.16 Photomontage Viewpoint 3 from Tin Ha Shan looking East

Figure 10.17 Photomontage Viewpoint 4 from Clear Water Bay Country Park Visitor Centre looking South

Figure 10.18 Photomontage Viewpoint 5 from Clear Water Bay Second Beach looking South East

Figure 10.19a Landscape and Visual Mitigation Plan – Submarine Outfall, Construction Phase

Figure 10.19b Landscape and Visual Mitigation Plan – Submarine Outfall, Operational Phase

Figure 10.20 Landscape and Visual Mitigation Plan – Sewage Treatment Plant

Figure 11.1 Built Heritage Impact Assessment – Study Area

Figure 11.2 Key Plan with Identified Built Heritage Resources

List of Appendices

Appendix 2.1 Preliminary Internal Layout of Po Toi O Sewage Treatment Plant

Appendix 2.2 Preliminary Work Programme

Appendix 4.1 Sewage Work at Po Toi O - Construction Noise (Unmitigated Scenario)

Appendix 4.2 Detailed Calculation for Unmitigated Operational Noise

Appendix 4.3 Sewage Work at Po Toi O - Construction Noise (Mitigated Scenario)

Appendix 4.4 Photographic Record of Representative Noise Sensitive Receivers

Appendix 4.5 Typical Noise Enclosure Design for Hand-Held Breaker

Appendix 5.1 Hydrodynamic and Water Quality Model Description

Appendix 5.2 Pollution Loading Inventory

Appendix 5.3 Pollution Loading Calculation for Po Toi O Sewage Treatment Plant

Appendix 5.4 Near-field Modelling

Appendix 5.5 Fluctuation of Sewage Level in Emergency Storage of Po Toi O Sewage Treatment Plant

Appendix 5.6 Figures for Modelled Results

Appendix 5.7 Sensitivity Test

Appendix 5.8 Water Quality Modelling Results

Appendix 6.1 Representative Photos of Terrestrial Habitats in the Study Area

Appendix 6.2 Species List

Appendix 6.3 Photographic Record of Species with Conservation Importance

Appendix 7.1 Representative Photos of Intertidal Habitats in the Study Area

Appendix 7.2 List of Species Found in Intertidal Survey

Appendix 7.3 List of Species Found in Fish Survey

Appendix 7.4 Marine Ecological (Dive) Survey Report

Appendix 7.5 List of Species Found in Benthic Survey (Grab Sampling)

Appendix 9.1a Sediment Quality Testing Results (SD1 & SD2)

Appendix 9.1b Sediment Quality Testing Results (SD3)

Appendix 9.2 Representative Historical Photos of Po Toi O

Appendix 9.3 Inspection Photos of Current Land Uses

Appendix 9.4 Dangerous Goods & Incident Records

Appendix 10.1 Tree Survey at Sewage Treatment Plant

Appendix 10.2 Tree Survey at Submarine Outfall

Appendix 11.1 Historic Maps of Poi Toi O

Appendix 11.2 Historical and Architectural Appraisal of Built Heritage Resources

List of ANNEXES

Annex A Implementation Schedule of Recommended Mitigation Measures

Annex B EIA Study Brief Checklist for reviewing the EIA Report