Water Supplies Department

Ngau Tam Mei Water Treatment Works Extension

Environmental Impact Assessment Report

282551-REP-080-05

Revised | 10 May 2024

Ngau Tam Mei Water Treatment Works Extension

Environmental Impact Assessment Report

282551-REP-080-05

Contents

Page

1 Introduction 1

1.1 Project Background 1

1.2 The Project 1

1.3 Site Location and History 3

1.4 EIA Study Brief 3

1.5 Designated Projects 4

1.6 Objectives of the EIA Study 4

1.7 Structure of this EIA Report 5

1.8 Nomenclature and Abbreviations 7

2 Project Description and Consideration of Alternatives 11

2.1 Purposes and Objectives of the Project under the Study 11

2.2 Need of the Project 11

2.3 Scenarios “With” and “Without” the Project 12

2.4 Environmental Benefits of the Project 12

2.5 Considerations of Options 12

2.6 Tackling Environmental Challenges 20

2.7 Proposed Design for the Project 21

2.8 Collating and Addressing Public Views 23

2.9 Tentative Implementation Programme 25

2.10 Concurrent Projects 25

3 Air Quality Impact 28

3.1 Legislation, Standards and Criteria 28

3.2 Description of the Environment 30

3.3 Representative Air Sensitive Receivers 32

3.4 Identification and Evaluation of Impacts during Construction Phase 33

3.5 Good Site Practice & Recommended Mitigation Measures 39

3.6 Identification and Evaluation of Impacts during Operational Phase 41

3.7 Residual Impacts 41

3.8 Conclusion 41

4 Noise Impact 42

4.1 Relevant Legislation, Standards and Criteria 42

4.2 Baseline Conditions 46

4.3 Noise Sensitive Receivers 50

4.4 Airborne Construction Noise Impact Assessment 52

4.5 Groundborne Construction Noise Impact Assessment 60

4.6 Fixed Noise Sources Impact Assessment 60

4.7 Conclusion 60

5 Water Quality Impact 62

5.1 Legislation, Standards, Guidelines and Criteria 62

5.2 Baseline Conditions 70

5.3 Representative Water Sensitive Receivers 72

5.4 Identification and Evaluation of Environmental Impacts – Construction Phase 72

5.5 Identification and Evaluation of Environmental Impacts – Operational Phase 75

5.6 Cumulative Impacts from Concurrent Project 75

5.7 Mitigation Measures Recommendations – Construction Phase 76

5.8 Mitigation Measures Recommendations – Operational Phase 80

5.9 Residual Impacts 81

5.10 Environmental Monitoring and Audit (EM&A) 81

5.11 Conclusion 81

6 Waste Management Implications 82

6.1 Legislation, Standards and Guidelines 82

6.2 Description of the Environment 84

6.3 Construction Phase 85

6.4 Operational Phase 99

6.5 Conclusion 99

7 Land Contamination 101

7.1 Legislation, Standards and Guidelines 101

7.2 Assessment Methodology 106

7.3 Description of the Environment 107

7.4 Future Land Use 109

7.5 Identification of Potentially Contaminated Site 110

7.6 Conclusion and Recommendation 110

8 Ecological Impact (Terrestrial and Aquatic) 111

8.1 Legislation, Standards and Guidelines 111

8.2 Methodology 112

8.3 Ecological Baseline Conditions 116

8.4 Evaluation of Habitats and Species 128

8.5 Impact Identification and Evaluation 136

8.6 Avoidance / Minimisation / Mitigation Measures 141

8.7 Residual Impacts 142

8.8 Environmental Monitoring and Audit (EM&A) 142

8.9 Conclusion 143

8.10 Reference 143

9 Fisheries Impact 145

9.1 Legislation, Standards and Guidelines 145

9.2 Assessment Methodology 145

9.3 Fisheries Baseline Conditions 146

9.4 Impact Identification and Evaluation 149

9.5 Mitigation Measures 149

9.6 Residual Impacts 150

9.7 Environmental Monitoring and Audit (EM&A) 150

9.8 Conclusion and Recommendations 150

9.9 References 150

10 Landscape and Visual Impact 151

10.1 Legislation, Standards and Guidelines 151

10.2 Assessment Methodology 153

10.3 Review of Planning and Development Control Framework 160

10.4 Landscape Baseline Study 161

10.5 Visual Baseline Study 165

10.6 Source of Landscape and Visual Impact Assessment 168

10.7 Recommended Landscape and Visual Mitigation Measures 172

10.8 Visual Impact Assessment 175

10.9 Significance of Residual Landscape and Visual Impacts 176

10.10 Conclusion 177

11 Impact on Cultural Heritage 179

11.1 Legislation, Standards and Guidelines 179

11.2 Assessment Methodology 180

11.3 Baseline Conditions 181

11.4 Cultural Heritage Impact Assessment 184

11.5 Mitigation Measures 185

11.6 Environmental Monitoring & Audit (EM&A) 186

11.7 Conclusion 186

11.8 Bibliography 187

12 Hazard to Life 189

12.1 Legislation, Standards and Guidelines 189

12.2 Hazard-to-life Impact Assessment 189

12.3 Conclusion 191

13 Environmental Monitoring & Audit 192

13.1 Introduction 192

13.2 Project Organization 192

13.3 EM&A Manual 192

13.4 Environmental Mitigation Implementation Schedule 193

13.5 EM&A Programme 193

14 Summary of Environmental Outcomes 198

14.1 General 198

14.2 Environmentally Friendly Options Considered and Incorporated to Avoid and Minimise Environmental Impact 198

14.3 Estimated Population Protected from Various Environmental Impacts 199

14.4 Environmental Benefits of Environmental Protection Measures Recommended 199

15 Conclusion 202

15.1 General 202

15.2 Air Quality 203

15.3 Noise 203

15.4 Water Quality 204

15.5 Waste Management 205

15.6 Land Contamination 205

15.7 Ecology 205

15.8 Fisheries 206

15.9 Landscape and Visual 206

15.10 Cultural Heritage 207

15.11 Hazard to life 208

Figures

Figure 1.1 Location of Project

Figure 2.1 Alternative Options Considered

Figure 2.2 Concurrent Projects

Figure 3.1 Locations of Concerned PATH Grids and Representative Air Sensitive Receivers

Figure 4.2.1 Assessment Area for Airborne Construction Noise

Figure 4.2.2 Assessment Area for Groundborne Construction Noise

Figure 4.2.3 Existing and Planned Noise Sources

Figure 4.3.1 Locations of Representative Noise Assessment Points for Airborne Construction Noise

Figure 5.1 Water Quality Impact Assessment Area and Water Sensitive Receivers

Figure 8.1 Ecological Impact Assessment Area, Survey Transect and Sampling Locations

Figure 8.2 Recognised Sites of Conservation Importance

Figure 8.3 Habitat Map

Figure 8.4 Location of Species of Conservation Importance

Figure 9.1 Surveyed Fishponds within Assessment Area

Figure 9.2 Current Status of Fishponds within Assessment Area

Figure 10.1 Aerial Photo

Figure 10.2 Outline Zoning Plan

Figure 10.3 Landscape Resources Plan

Figure 10.4 Landscape Resources Photographs

Figure 10.5 Landscape Character Areas (LCAs) Plan

Figure 10.6 Landscape Character Areas (LCAs) Photographs

Figure 10.7 Baseline of Key Visually Sensitive Receivers

Figure 10.8 Visually Sensitive Receivers Photographs

Figure 10.9 Location of Photomontage Viewpoint

Figure 10.10 Photomontage

Figure 11.1 Cultural Heritage Assessment Area

Figure 11.2 Geology

Figure 11.3 Previous Archaeological Investigation

Figure 12.1 Location of Potentially Hazardous Installation

Appendices

Appendix 2.1

Tentative Construction Programme

Appendix 4.3.1

Photos of Representative Existing NSRs

Appendix 4.4.1

SWL of PME

Appendix 4.4.2

Detailed PME for each workfront

Appendix 4.4.3

Locations of Workfronts

Appendix 4.4.4

Unmitigated Airborne Construction Noise Impacts

Appendix 4.4.5

Unmitigated Construction Noise Impacts at Various Representative Floor Levels

Appendix 4.4.6

Sketch of Typical Temporary Noise Barrier & Enclosure

Appendix 4.4.7

Mitigated Airborne Construction Noise Impact

Appendix 4.4.8

Mitigated Construction Noise Impacts at Various Representative Floor Levels

Appendix 7.1

Land Contamination Review

Appendix 8.1

Representative Photos of Habitat Types

Appendix 8.2

Description of Freshwater Communities Sampling Stations

Appendix 8.3

List of Floral Species Recorded

Appendix 8.4

List of Fauna Species Recorded

Appendix 8.5

Representative Photos of Species of Conservation Importance

Appendix 10.1

Broad Brush Tree Survey Report for NTM WTW & PSR Extension & Chamber G Modification

Appendix 10.2

Individual Tree Survey for Trunkmain between NTM WTW & NTM FWPSR

Appendix 10.3

Individual Tree Survey for Trunkmain between Ching Yau Road & San Tam Road

Appendix 12.1

Societal Risk Guidelines

Appendix 15.1

Key Assessment Assumptions and Limitation of Assessment Methodologies

Appendix 15.2

Summary of Environmental Impacts Associated with the Project

1 Introduction

1.1 Project Background

1.1.1.1 The existing Ngau Tam Mei Water Treatment Works (NTM WTW) and associated treated water transfer and distribution system were commissioned in 2000 to provide treated water capacity of 230,000m³/day. The treated water is supplied to Yuen Long, Ngau Tam Mei, San Tin and Mai Po Areas.

1.1.1.2 With consideration on the planned and potential developments in Yuen Long area, the future water demand will render the existing water treatment capacity of NTM WTW to be exceeded by Year 2030. In this connection, it is necessary to expand and upgrade the existing NTM WTW and treated water transfer and distribution systems by end of Year 2030 to meet the development programme.

1.1.1.3 Ove Arup & Partners Hong Kong Ltd (Arup) was commissioned by the Water Supplies Department (WSD) of the Government of the Hong Kong Special Administrative Region on 15 June 2021 to carry out the Agreement No. CE 78/2020 (WS) on Ngau Tam Mei Water Treatment Works and Primary Service Reservoir Extension – Investigation, Design and Construction.

1.1.1.4 The Agreement No. CE 78/2020 (WS) will include the extension of NTM WTW within the site compound with the aim of upgrading the water treatment capability and enhancing the treatment efficiency. It also includes the construction of extension of NTM Fresh Water Primary Service Reservoir (FWPSR) adjacent to the existing FWPSR and laying of fresh water trunk mains of 1600mm from the extended NTM WTW to FWPSR.

1.1.1.5 The Study under this Agreement No. CE 78/2020 (WS) will cover the whole Ngau Tam Mei Water Treatment Works Extension Project (hereinafter referred to as the “Study”), which also includes the works under Agreement No. CE 62/2022 (WS) – “Laying of Fresh Water Trunk Mains from Ngau Tam Mei Fresh Water Primary Service Reservoir to Tan Kwai Tsuen and Modification of Raw Water Tunnel Junction (Chamber G) – Design and Construction”.

1.2 The Project

1.2.1.1 As discussed in Section 1.1, the Study will cover the investigation, design and construction of NTM WTW extension, NTM FWPSR extension, Chamber G and fresh water trunk main, and the following works will be included:

· Provision of additional treatment facilities within the existing NTM WTW compound to increase the water treatment capacity of NTW WTW;

· Construction of an extension of NTM FWPSR with a capacity of 54,000m³ adjacent to the existing FWPSR;

· Laying of about 9.5km of fresh water trunk mains of diameters ranging from 1600 mm to 2000 mm for delivery of the treated water from the expanded NTM WTW to the NTM FWPSR and from the FWPSR to the existing fresh water distribution system near Tan Kwai Tsuen; and

· Modification of the existing raw water tunnel junction (Chamber G) located near NTM WTW.

1.2.1.2 Upon reviewing the potential Designated Project (DP) elements of the Study under Item Q.1 of Part I of Schedule 2 of the revised Environmental Impact Assessment Ordinance (EIAO), the environmental impacts of the construction and operation of the aforementioned works will be addressed in two separate reports:

· The Environmental Impact Assessment (EIA) of the Study (see Section 1.2.1.3) would only address DP elements of the Study; and

· A separate Preliminary Environmental Review (PER) report (see Section 1.2.1.4) would address the remaining non-DP elements of the Study.

1.2.1.3 The EIA of the Study (hereinafter referred to as the “Project”) would only include Project elements that fall into DP elements (see Figure 1.1), which includes the following:

· Laying of about 1km (around 750m from NTM WTW to NTM FWPSR and around 250m from Ching Yau Road to San Tam Road) of fresh water trunk mains of diameter 1600 mm, which encroach into boundary of the Conservation Area (CA), for delivery of the treated water from the expanded NTM WTW to the NTM FWPSR and from the FWPSR to the existing fresh water distribution system near Tan Kwai Tsuen; and

· Modification of the existing raw water tunnel junction (Chamber G) located near NTM WTW within Lam Tsuen Country Park and CA.

1.2.1.4 A separate PER Report would be prepared to include the non-DP elements of the Study, which are listed below. These elements of the Study would also be considered as concurrent project of the Project.

· Provision of additional treatment facilities within the existing NTM WTW compound to increase the water treatment capacity of NTW WTW;

· Construction of an extension of NTM FWPSR with a capacity of 54,000m³ adjacent to the existing FWPSR; and

· Laying of about 8.5km of fresh water trunk mains of diameters ranging from 1600 mm to 2000 mm, which do not encroach into boundary of Lam Tsuen Country Park or CA, for delivery of the treated water from the expanded NTM WTW to the NTM FWPSR and from the FWPSR to the existing fresh water distribution system near Tan Kwai Tsuen.

1.2.1.5 Figure 1.1 shows the location of the Project. Detailed description of the Project is presented in Section 2.7.

1.3 Site Location and History

1.3.1.1 The Project is located near Ngau Tam Mei within the Yuen Long District. The proposed fresh water trunk mains mainly run through the existing roads in rural areas of Ngau Tam Mei. A section of the proposed fresh water trunk mains runs from NTM WTW towards the NTM FWPSR along an existing access road, which cuts through the CA and are aligned adjacent to Lam Tsuen Country Park. Another section of the proposed fresh water trunk mains to be constructed within the water works reserve between Ching Yau Road and San Tam Road falls within CA.

1.3.1.2 The existing raw water tunnel junction (Chamber G) is an underground facility located to the southeast of NTM WTW for distribution of raw water to various WTWs including NTM WTW. The existing Chamber G is an underground Y-shaped chamber of about 225m² on plan within the Lam Tsuen Country Park and the proposed tunnels and connection chambers would fall within the underground stratum of Lam Tsuen Country Park and CA.

1.4 EIA Study Brief

1.4.1.1 In accordance with the requirements of Section 5(1) of the Environmental Impact Assessment Ordinance (EIAO), a Project Profile (No. PP-608/2020) for the Project was submitted to the Director of Environmental Protection (DEP) for application for an EIA Study Brief (SB) on 6 August 2020. Pursuant to Section 5(7)(a) of the EIAO, the DEP issued a SB (No.: ESB-333/2020) dated 14 September 2020 for the EIA Study.

1.4.1.2 Nevertheless, according to Clause 3.4 of the revised Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM), “For a designated project under Item Q.1 of Part I of Schedule 2 to the Ordinance (i.e. a project involving works partly or wholly in the environmental sensitive areas mentioned in Item Q.1), which is not otherwise a designated project listed in items A to P of Schedule 2 to the Ordinance, the EIA study brief shall set out in such a way that the assessments and derivation of mitigation measures will focus on the environmental implications of the project on the environmental sensitive areas.” This EIA would therefore focus on the environmental implications of the Project elements, as listed out in Section 1.2.1.3, which encroach onto the environmental sensitive areas, i.e. Lam Tsuen Country Park and CA.

1.5 Designated Projects

1.5.1.1 The Project comprises the following which are classified as Designated Projects (DPs) as per Schedule 2, Part I of EIAO:

· Item Q.1 – All projects involving earthworks, dredging works and other building works partly or wholly in an existing country park or a conservation area.

1.5.1.2 The proposed fresh water trunk mains would run through CA.

1.5.1.3 In addition, the modification works at Chamber G including the proposed raw water mains and by-pass tunnels are underground works which would fall within the underground stratum of Lam Tsuen Country Park and CA.

1.6 Objectives of the EIA Study

1.6.1.1 According to Section 1.5 of the EIA Study Brief (No.: ESB-333/2020), this EIA study is to provide information on the nature and extent of environmental impacts arising from the construction and operation of the Project and associated works that will take place concurrently. This information will contribute to decisions by the Director on:

· the overall acceptability of any adverse environmental consequences that are likely to arise as a result of the Project;

· the conditions and requirements for the detailed design, construction and operation of the Project to mitigate against adverse environmental consequences wherever practicable; and

· the acceptability of residual impacts after the proposed mitigation measures are implemented.

1.6.1.2 The objectives of the EIA study are as follows:

· to describe the Project and associated works together with the requirements and environmental benefits for carrying out the Project;

· to identify and describe the elements of community and environment likely to be affected by the Project and/ or likely to cause adverse impacts to the Project, including natural and man-made environment and the associated environmental constraints;

· to identify and quantify emission sources and determine the significance of impacts on sensitive receivers and potential affected uses;

· to identify and quantify potential waste management issues and impacts arising as a result of the construction and operation activities of the Project;

· to identify and quantify contaminated land within any project area for development works, and to propose measures to avoid disposal in the first instance;

· to identify and quantify any potential ecological and fisheries impacts arising from the construction and operation of the Project and to propose measures to mitigate these impacts;

· to identify any potential landscape and visual impacts and to propose measures to mitigate these impacts;

· to identify any negative impacts on cultural heritage and to propose measures to mitigate these impacts;

· to propose the provision of infrastructures or mitigation measures to minimise pollution, environmental disturbance and nuisance during construction and operation of the Project;

· to investigate the feasibility, effectiveness and implications of the proposed mitigation measures;

· to identify, predict and evaluate the residual (i.e. after practicable mitigation) environmental impacts and the cumulative effects expected to arise during the construction and operation phases of the Project in relation to the sensitive receivers and potential affected uses;

· to identify, assess and specify methods, measures and standards, to be included in the detailed design, construction and operation of the Project which are necessary to mitigate these residual environmental impacts and cumulative effects and reduce them to acceptable levels;

· to design and specify the environmental monitoring and audit requirements; and

· to identify any additional studies necessary to implement the mitigation measures or monitoring and proposals recommended in the EIA report.

1.7 Structure of this EIA Report

1.7.1.1 The structure of this EIA Report is tabulated in Table 1.1 with the aim of each chapter.

Table 1.1 – Structure of this EIA Report

Chapter	Title	Aims
1	Introduction	To introduce the project background and the objectives of the report.
2	Project Description and Consideration of Alternatives	To summarise the various options and scope for various environmental aspects. To describe relevant main construction / engineering aspects of the recommended layout.
3	Air Quality Impact	To present the legislation, methodology, assessment and recommendations for air quality impacts.
4	Noise Impact	To present the legislation, methodology, assessment and recommendations for noise impacts.
5	Water Quality Impact	To present the legislation, methodology, assessment and recommendations for water quality impacts.
6	Waste Management Implications	To present the legislation, methodology, assessment and recommendations for waste management.
7	Land Contamination	To present the legislation, methodology, assessment and recommendations for land contamination.
8	Ecological Impact (Terrestrial and Aquatic)	To present the legislation, methodology, assessment and recommendations for ecological impacts.
9	Fisheries Impact	To present the legislation, methodology, assessment and recommendations for fisheries impacts.
10	Landscape and Visual Impact	To present the legislation, methodology, assessment and recommendations for landscape and visual impacts.
11	Impact on Cultural Heritage	To present the legislation, methodology, assessment and recommendations for cultural heritage impacts.
12	Hazard to Life	To present the legislation, methodology, assessment and recommendations for hazard impacts.
13	Environmental Monitoring & Audit (EM&A)	To present the EM&A requirements.
14	Summary of Environmental Outcomes	To present a summary of the key environmental outcomes arising from the EIA study.
15	Conclusion	To summarise the findings and conclude the overall acceptability of the project.

1.8 Nomenclature and Abbreviations

Abbreviation	Full Title
AFCD	Agriculture, Fisheries and Conservation Department
AFFS	Accredited Fish Farm Scheme
AIA	Archaeological Impact Assessment
AMO	Antiquities and Monuments Office
ANL	Acceptable Noise Level
APCO	Air Pollution Control Ordinance
AQMS	Air Quality Monitoring Station
AQO	Air Quality Objective
ASR	Air Sensitive Receiver
BHIA	Built Heritage Impact Assessment
BMP	Best Management Practice
C&D	Construction and Demolition
C&DMMP	Construction and Demolition Material Management Plan
CA	Conservation Area
CAP	Contamination Assessment Plan
CAR	Contamination Assessment Report
CEDD	Civil Engineering and Development Department
CHAA	Cultural Heritage Assessment Area
CHIA	Cultural Heritage Impact Assessment
CITES	Convention on International Trade in Endangered Species
CNMP	Construction Noise Management Plan
CNP	Construction Noise Permit
COC	Chemical of Concern
CWPR	Chemical Waste Producers Registration
CWTC	Chemical Waste Treatment Centre
CZ	Consultation Zone
DA-TM	Technical Memorandum on Noise from Construction Work in Designated Areas
DEVB	Development Bureau
DG	Dangerous Good
DP	Designated Project
DSS-TM	Technical Memorandum for Effluents Discharged into Drainage and Sewerage Systems Inland and Coastal Waters
EIA	Environmental Impact Assessment
EIAO	Environmental Impact Assessment Ordinance, Cap 499
EIAO-TM	Technical Memorandum on Environmental Impact Assessment Process
EM&A	Environmental Monitoring & Audit
EMIS	Environmental Mitigation Implementation Schedule
EP	Environmental Permit issued under EIAO
EPD	Environmental Protection Department
ER	Engineer’s Representative
ET	Environmental Team
ETWB	Environment, Transport and Works Bureau
FSD	Fire Services Department
FSP	Fine Suspended Particulate
FWPSR	Fresh Water Primary Service Reservoir
GESF	Guidelines for Estimating Sewage Flows for Sewage Infrastructure Planning
GI	Ground Investigation
GW-TM	Technical Memorandum on Noise from Construction Work other than Percussive Piling
HKAQO	Hong Kong Air Quality Objectives
HKPSG	Hong Kong Planning Standards and Guidelines
HKRG	Hong Kong Risk Guidelines
IEC	Independent Environmental Checker
IF	Influencing Factor
IND-TM	Technical Memorandum for the Assessment of Noise from Places other than Domestic Premises, Public Places or Construction Sites
KFBG	Kadoorie Farm and Botanic Garden
LandsD	Lands Department
LCA	Landscape Character Area
LR	Landscape Resource
LVIA	Landscape and Visual Impact Assessment
MPNR	Mai Po Nature Reserve
MTR	Mass Transit Railway
NAP	Noise Assessment Point
NCO	Noise Control Ordinance
NRMM	Non-Road Mobile Machinery
NTM	Ngau Tam Mei
NTM FWPSR	Ngau Tam Mei Fresh Water Primary Service Reservoir
NTM WTW	Ngau Tam Mei Water Treatment Works
NSR	Noise Sensitive Receiver
ODP	Outline Development Plans
OSCG	On-site Chlorine Generation
OVT	Old and Valuable Tree
OZP	Outline Zoning Plan
PCB	Polychlorinated Biphenyl
PCR	Petroleum Carbon Ranges
PCW	Prescribed Construction Works
PFA	Pulverised Fuel Ash
PHI	Potentially Hazardous Installation
PlanD	Planning Department
PME	Powered Mechanical Equipment
PRD	Pearl River Delta
ProPECC	Professional Persons Environmental Consultative Committee
QPME	Quality Powered Mechanical Equipment
QRA	Quantitative Risk Assessment
RAP	Remediation Action Plan
RBRG	Risk-Based Remediation Goals
RR	Remediation Report
RSP	Respirable Suspended Particulates
SAI	Site of Archaeological Interest
SB	Study Brief
SBZ	Safety Buffer Zone
SVOC	Semi-Volatile Organic Chemical
SI	Site Investigation
SPME	Specified Powered Mechanical Equipment
SS	Suspended Sediments (or Solids)
SSSI	Sites of Special Scientific Interest
TPI	Trees of Particular Interest
TSP	Total Suspended Particulate
UFF	Unit Flow Factor
ULSD	Ultra-low Sulphur Diesel
USEPA	United States Environmental Protection Agency
VE	Visual Envelope
VOC	Volatile Organic Chemical
VSR	Visual Sensitive Receiver
WCZ	Water Control Zone
WDO	Waste Disposal Ordinance
WENT	West New Territories
WMP	Waste Management Plan
WPCO	Water Pollution Control Ordinance
WQO	Water Quality Objective
WSD	Water Supplies Department
WSR	Water Sensitive Receiver
WTW	Water Treatment Works
ZVI	Zone of Visual Influence

2 Project Description and Consideration of Alternatives

2.1 Purposes and Objectives of the Project under the Study

2.1.1.1 The existing Ngau Tam Mei Water Treatment Works (NTM WTW) provides treated water capacity of 230,000m³/day and delivers the treated water to the Ngau Tam Mei Fresh Water Primary Service Reservoir (NTM FWPSR) and the existing fresh water distribution system near Tan Kwai Tsuen through fresh water trunk mains. The treated water is subsequently supplied to Yuen Long, Ngau Tam Mei, San Tin and Mai Po Areas.

2.1.1.2 The Study aims to increase the water treatment capacity of the existing NTM WTW to 640,000m³/day and enhance the overall treatment efficiency, by extension of the NTM WTW, and to upgrade the associated raw water and treated water transfer and distribution system, by extension of NTM FWPSR, laying of fresh water trunk mains and modification of Chamber G, to cope with the increase of fresh water demand owing to the planned and potential development in Yuen Long in the future. The proposed fresh water trunk mains and modification of Chamber G of the Project form part of the treated water transfer and distribution system to be upgraded. Apart from satisfying the genuine need from the public, the Project also strives to minimise the potential environmental impacts during the course of construction and operation.

2.2 Need of the Project

2.2.1.1 As discussed in Section 1.1, the planned and potential development in Yuen Long area, including Yuen Long South Development, Hung Shui Kiu New Development Area, housing developments at Wang Chau, Tan Kwai Tsuen, Long Bin, etc., will generate significant water demand in Yuen Long, which will render the existing water treatment capacity of the NTM WTW be exceeded by Year 2030. It is therefore necessary to expand and upgrade the existing NTM WTW by end of Year 2030 to secure the fresh water supply for the future population.

2.2.1.2 With the potential increase of fresh water demand, the raw water distribution system, i.e. the raw water tunnel junction (Chamber G), would also require modification to supply sufficient raw water for water treatment at the NTM WTW.

2.2.1.3 As the treated water from NTM WTW is firstly transferred to NTM FWPSR for providing a treated water supply to Yuen Long, Ngau Tam Mei, San Tin and Mai Po areas, with the proposed incremental of treatment capacity of NTM WTW, the associated treated water transfer and distribution system, i.e. NTM FWPSR and fresh water trunk mains, would require expansion and upgrade in order to deliver the increased supply of treated water to the aforementioned areas. The proposed fresh water trunk mains of the Project form part of the treated water transfer and distribution system.

2.3 Scenarios “With” and “Without” the Project

2.3.1 Without Project Scenario

2.3.1.1 Without the Project in place, there would not be sufficient supply of raw water for water treatment at the extended NTM WTW with the increased treatment capacity. The amount of treated water for fresh water supply would remain the same. In addition, the treated water transfer and distribution system, which includes the fresh water trunk mains, could not support the increased treated water supply associated with the NTM WTW and NTM FWPSR extension. As a result, there would be a shortage of fresh water supply as anticipated due to the increase in population associated with the planned and potential developments in Yuen Long.

2.3.2 With Project Scenario

2.3.2.1 With the Project in place, the increased fresh water supply due to the extension work of NTM WTW would be able to meet the potential increase of fresh water demand and deliver to the planned and potential developments in Yuen Long area by the end of Year 2030. This would ensure reliable and adequate supply of fresh water to the future population in Yuen Long. In addition, the operation of the fresh water trunk mains and Chamber G would not cause adverse environmental impacts on air quality, noise, water quality, waste management implications, land contamination, ecology, fisheries, cultural heritage and hazard to life. The environmental trends with the Project in place would be similar to the existing environment.

2.4 Environmental Benefits of the Project

2.4.1.1 The major environmental benefit of the Project is to provide treated and reliable fresh water supply to meet the demand of future population. The design of extension works of NTM WTW will be capable of producing the final water with quality complying with the Treated Water Quality Objective as stated in the Scope of the Study, while for individual water quality parameters not referred to standard stated in the Scope, they will be meeting the Hong Kong Drinking Water Standard.

2.5 Considerations of Options

2.5.1 General

2.5.1.1 The fresh water supply to the north-west of New Territories is currently supplying by the existing NTM WTW and Au Tau WTW, which the supply networks under these two WTWs are interconnected in order to cater for the fresh water demand.

2.5.1.2 As discussed in Section 1, NTM WTW was commissioned in Year 2000 with a treatment capacity of 230,000m³/day for supplying fresh water to Yuen Long, Ngau Tam Mei, San Tin and Mai Po areas.

2.5.1.3 Due to the increase in water demand from planned development, it is understood that the existing water treatment capacity of NTM WTW will be insufficient by the end of Year 2030 and therefore it is necessary to extend the capacity of NTM WTW and associated raw water and fresh water transfer facilities by the end of Year 2030.

2.5.1.4 Due considerations have been given in formulating options to address the environmental challenges in this Project. The hierarchy of “Avoid, Minimise and Mitigate” has been fully adopted in the process to protect the environment as much as practicable. Summary of the key considerations for options on the layout, alignment, design, construction methodology and sequence of construction works of the Project is given below.

2.5.2 Consideration of Fresh Water Trunk Mains Alignment between NTM WTW and NTM FWPSR

2.5.2.1 Existing fresh water trunk mains are located along the existing access road, which passes through the CA and is aligned immediately adjacent to the Lam Tsuen Country Park. In order to accommodate the additional flow from NTM WTW extension to the expanded FWPSR under the Study, laying of a fresh water trunk main of 1,600mm diameter was proposed. Different alignment for the additional fresh water trunk mains alignment between the NTM WTW and NTM FWPSR have been identified to achieve a balance between operation considerations and environmental impacts. A total of two alignment options have been identified and are discussed in detail in the following sections. Both options have avoided encroachment into the Lam Tsuen Country Park. The options considered are also shown in Figure 2.1:

· Option 1 – Alignment along the boundary of CA; and

· Option 2 – Alignment along the access road/ slope adjacent to existing access road.

2.5.2.2 Option 1 is an alignment which would deviate with the existing fresh water trunk mains from NTM WTW to NTM FWPSR and partially running along the boundary of CA with a total length of approx. 950m. (see Figure 2.1) This option could avoid major encroachment to the CA. Nevertheless, it is approx. 200m longer than Option 2 and it would complicate the operation and maintenance (O&M) of the fresh water trunk mains comparing to Option 2, which deviated from the alignment of the existing fresh water trunk mains. In addition, Option 1 would be constructed by open cut method due to small bending radius and complicated pipe routing and terrain, more trees would be affected.

2.5.2.3 Option 2 has been adopted in the Project Profile and hence in the EIA Study Brief (SB). It is proposed to replace the existing fresh water trunk main with diameter of 1,400mm with an upgraded 1,600mm diameter fresh water trunk main, with a total length of approx. 750m (see Figure 2.1). The proposed mainlaying works would be mainly located along the existing access road/slope adjacent to existing access road. No encroachment on any floral species of conservation importance is expected. No significant ecological impact to the CA is anticipated.

2.5.2.4 Based on the findings from the ecological survey, no species of conservation importance was identified along the alignment of Option 1 and Option 2. Existing trees will be retained as far as possible to preserve the landscape. Trees unavoidably affected by the project shall be transplanted. Affected trees that are not suitable for transplantation and to be felled shall be compensated in not less than 1:1 in quantity.

2.5.2.5 A summary of the considered fresh water trunk mains alignment options between NTM WTW and NTM FWPSR is given in Table 2.1 with the preferred option identified for ease of reference.

Table 2.1 – Summary of Fresh Water Trunk Mains Alignment Options between NTM WTW & FWPSR

Alignment Options	Pros	Cons	Preferred Option (Y/N)
Option 1 Alignment along the boundary of CA	- Avoids major encroachment to CA	- Poses O&M difficulties - More trees would be affected	N
Option 2 Alignment along the existing access road/ slope adjacent to existing access road	- No major ecological impact to the CA, along existing access road/ slope adjacent to existing access road - No encroachment on any floral species of conservation importance	- Encroachment to boundary of the CA	Y

2.5.2.6 Option 2 would provide a balance between the O&M considerations and environmental impacts. Hence, it is considered that Option 2 (i.e. alignment along the existing access road/ slope adjacent to existing access road) is the preferred option and would be adopted.

2.5.3 Consideration of Fresh Water Trunk Mains Alignment between Ching Yau Road and San Tam Road

2.5.3.1 As discussed in Section 1.2, the Project involves laying of 1 km fresh water trunk mains which encroach into boundary of the CA for delivery of the treated water from the expanded NTM WTW to the NTM FWPSR and from the FWPSR to the existing fresh water distribution system near Tan Kwai Tsuen. The proposed fresh water trunk mains which run along the water works reserve between Ching Yau Road and San Tam Road would deviate from the existing road and cut through a CA before approaching San Tam Road. A total of two options have been identified to avoid and minimise the impacts on neighbouring environmental resources and are discussed in detail in the following sections. The options considered are also shown in Figure 2.1:

· Option 3 – Construction of a new fresh water trunk mains; and

· Option 4 – Replacement of the existing fresh water trunk main with an upgraded 1,600mm diameter fresh water trunk main.

2.5.3.2 Option 3 is a new fresh water trunk main, which cuts through a CA between Ching Yau Road and San Tam Road, proposed under the Project Profile (PP) and Environmental Impact Assessment Study Brief (EIA SB). This option is proposed to establish an optimal water supply system with minimal pressure loss. However, the alignment encroaching the CA is located in habitats including woodland. The proposed mainlaying works would involve tree-felling and excavation of natural terrain. Associated ecological impact is anticipated.

2.5.3.3 Option 4 replaces the existing fresh water trunk main with diameter of 1,400mm with an upgraded 1,600mm diameter fresh water trunk main, instead of constructing a new fresh water trunk main beside the existing ones. Although encroachment of the CA is still anticipated, less ecological impact is anticipated as the area at the existing fresh water trunk mains has been disturbed when the mains were constructed. The area of disturbance would be smaller when compared to construction of a new fresh water trunk main as it would be limited to the area where the existing fresh water trunk mains are located.

2.5.3.4 A summary of the considered fresh water trunk mains alignment options between Ching Yau Road and San Tam Road is given in Table 2.2 with the preferred option identified for ease of reference.

Table 2.2 – Summary of Fresh Water Trunk Mains Alignment between Ching Yau Road & San Tam Road

Alignment Options	Pros	Cons	Preferred Option (Y/N)
Option 3 Construction of a new fresh water trunk main	- Better hydraulic performance to maintain a more resilient water supply with an additional main	- Larger area of tree felling works and excavation of natural terrain	N
Option 4 Replacement of the existing fresh water trunk main with an upgraded 1,600mm diameter fresh water trunk main	- Tree felling works and excavation at a previously disturbed area.	- N/A	Y

2.5.3.5 Option 4 would minimise the ecological impacts associated with the construction of fresh water trunk mains within the CA as listed above. Hence, it is considered that Option 4 (i.e. replacement of the existing fresh water trunk main with an upgraded 1,600mm diameter fresh water trunk main) is the preferred option and would be adopted.

2.5.4 Consideration of Options for Modification of Chamber G

2.5.4.1 The existing Chamber G is an underground facility located to the southeast of NTM WTW used for distribution of raw water to various WTWs, including NTM WTW. The raw water tunnels and access tunnel to the NTM WTW are located within the CA and Lam Tsuen Country Park. A total of 4 options in modification of Chamber G, which would involve construction of water pipes and access tunnels, have been considered in terms of the impact of operation and maintenance as well as surrounding environment. Modification works would be conducted by expanding the existing access tunnel connecting Chamber G for laying new raw water mains and constructing new water tunnel with new water main. The options considered are discussed below and shown in Figure 2.1:

· Option 5 – Construction of new water pipe underneath existing access tunnel with new tunnels to connect existing Western Aqueduct and existing Ngau Tam Mei/Tai Po Tau Aqueduct as shown in the Project Profile (No. PP-608/2020) and hence in the EIA SB (No.: ESB-333/2020);

· Option 6 – Construction of new water pipe parallel to existing access tunnel with new tunnels to connect Western Aqueduct and Ngau Tam Mei/Tai Po Tau Aqueduct; and

· Option 7 – Construction of new water pipe parallel to existing access tunnel with new tunnels to connect Western Aqueduct and Ngau Tam Mei/Tai Po Tau Aqueduct with additional chambers at collection points.

· Option 8 – Construction of a combined access tunnel and two additional bypass access tunnels to the proposed new Chambers G2, G3 and G4.

2.5.4.2 The horizontal alignment of the new water main of Option 5 follows the existing access tunnel prior to turning eastward toward the existing Western Aqueduct. One set of valves would be installed between the new water pipe, existing Western Aqueduct and new water tunnel towards Ngau Tam Mei / Tai Po Tau Aqueduct (see Figure 2.1). The benefit of this option is using minimal effort in construction works to meet the minimum need. Drill and break method is required which will cause potential issues to the operation and maintenance of the Chamber G and Chamber G1. Moreover, construction works within the CA will be required as the existing access tunnel is located in the CA.

2.5.4.3 The horizontal alignment of the new water main of Option 6 runs parallel on the east side of the existing access tunnel prior to turning eastward toward the existing Western Aqueduct. One set of valves would be installed between the new water pipe, existing Western Aqueduct and new water tunnel towards Ngau Tam Mei / Tai Po Tau Aqueduct. The benefit of this option is less construction works are required and less disturbance to the CA is anticipated to the existing access tunnel when compared with Option 5 as the aboveground construction works of new tunnel will be conducted outside the CA. The existing Chamber G and G1 are identical to Option 5 for Option 6.

2.5.4.4 The horizontal alignment of the new water main of Option 7 runs parallel on the east side of the existing access tunnel prior to turning eastward toward the existing Western Aqueduct. Three new chambers with valves would be constructed at each connection points. The benefit of this option is the increased flexibility of the raw water network supply system although it involves additional excavation when compared with Option 5 and Option 6. Aboveground construction works of new tunnel will be conducted outside the CA. The existing Chamber G and G1 are identical to Option 5 and Option 6 for Option 7.

2.5.4.5 The horizontal alignment of the two additional bypass tunnels of Option 8 delinks the long duration excavation of the proposed Chambers G2 and G3. Although it involves additional excavation, it would eliminate the long critical path due to single excavation direction, and hence reduce the construction programme. The duration of construction activities and the associated environmental impacts would also be shortened.

2.5.4.6 A summary of the considered options for modification of Chamber G is given in Table 2.3 with the preferred option identified for ease of reference.

Table 2.3 – Summary of Options for Modification of Chamber G

Alignment Options	Pros	Cons	Preferred Option (Y/N)
Option 5 Construction of new water pipe underneath existing access tunnel with new tunnels to connect existing Western Aqueduct and existing Ngau Tam Mei/Tai Po Tau Aqueduct	- Least construction works is required to meet the minimum need for additional raw water supply	- Cause disturbance to the existing access tunnel - Cause potential O&M issue to the Chamber G and Chamber G1 - Involve aboveground construction works within the CA	N
Option 6 Construction of new water pipe parallel to existing access tunnel with new tunnels to connect Western Aqueduct and Ngau Tam Mei/Tai Po Tau Aqueduct	- Avoid aboveground construction works within the CA - Less disturbance to the existing access tunnel due to separated new raw water tunnel	- Cannot fulfil O&M requirement for the new raw water tunnel	N
Option 7 Construction of new water pipe parallel to existing access tunnel with new tunnels to connect Western Aqueduct and Ngau Tam Mei/Tai Po Tau Aqueduct with additional chambers at collection points	- Avoid above ground construction works within the CA - Less disturbance to the existing access tunnel due to separated new raw water tunnel - Higher flexibility of the raw water network supply system with new connection chambers for O&M	- Additional excavation material and cost from the construction of chambers - Cannot fulfil fire safety requirements for vehicles accessing new tunnel/chambers	N
Option 8 Construction of a combined access tunnel and two additional bypass access tunnels to the proposed new Chambers G2, G3 and G4	- Avoid above ground construction works within the CA - Fulfil O&M and fire safety requirements for the new access tunnel and chambers with high flexibility of raw water network supply system - Eliminate long critical path due to excavation of the proposed Chamber G2 and G3 in single construction direction	- Additional excavation material and cost from combined tunnel and bypass access tunnel and larger chambers	Y

2.5.4.7 Option 8 would provide more reliable and higher flexibility in terms of the construction programme due to the proposed two additional bypass access tunnels. Since Option 8 incorporates ventilation and fire safety provisions, it would also enhance the safety of the working environments for future operators when they are carrying out maintenance works. Hence, it is considered that Option 8 (i.e. Construction of two additional bypass access tunnels as the branch of the access tunnel to the proposed Chamber G2, G3 and G4) is the preferred option and would be adopted.

2.5.5 Consideration of Options for Construction Methodology

2.5.5.1 Other than options for the proposed layout, alignment and design of the Project, etc. as discussed above, various construction methodologies have also been considered in view of avoidance and minimisation of potential environmental impacts as much as practicable.

2.5.6 Options for Construction Method of Fresh Water Trunk Mains

2.5.6.1 The fresh water trunk mains would be constructed by open cut method to ensure construction practicability and ease of maintenance. In consideration of the accessibility for future maintenance by WSD, open cut method is preferred as far as possible. For the proposed fresh water trunk mains between NTM WTW and NTM FWPSR, the alignment is located along the existing ~6m wide access road at the edge of the hillsides without suitable location for jacking and receiving pits. Therefore, conventional method (i.e. open cut method) rather than trenchless method is considered for laying of the proposed fresh water trunk mains.

2.5.6.2 For the proposed fresh water trunk mains between Ching Yau Road and San Tam Road, the alignment is along the existing water trunk main parallel to the edge of the hillsides, which is located within a ~10m wide water works reserve area between Ching Yau Road and San Tam Road. Conventional method (i.e. open cut method) is proposed for the mainlaying works to allow for future maintenance purpose.

2.5.6.3 The mainlaying works would also be conducted by sections throughout the alignment so that the works site would be limited in size to minimise the potential environmental impacts, e.g. construction dust and noise impact, on the nearby sensitive receivers.

2.5.7 Options for Construction Method of Modification of Chamber G

2.5.7.1 The existing Chamber G is an underground facility with associated underground raw water tunnels and raw water mains. The proposed raw water main connecting the Western Aqueduct supply tunnel of NTM WTW would be laid within the combined access tunnel. As the proposed combined access tunnel is located underground within both the Lam Tsuen Country Park and CA, mined excavation with drill and break method rather than mined excavation with drill and blast method is preferred to minimise the ecological impacts on these sites of conservation importance in the vicinity. Hence, aboveground works within the Lam Tsuen Country Park and CA could be totally avoided.

2.5.7.2 Comparison on the pros and cons is summarised in Table 2.4. Mined excavation with drill and blast method would have a higher production rate for tunnel excavation, but it would induce higher risk of affecting the existing operation and WSD’s asset and create hazard to the population in NTM WTW and nearby villages due to the use and transportation of explosives. Therefore, mined excavation with drill and break method is chosen to minimise overbreak and avoid any potential safety risks.

Table 2.4 – Summary of options for construction method of Chamber G

Options	Pros	Cons	Preferred Option (Y/N)
Mined Excavation with Drill and Break	- Minimise overbreak and thus lesser excavated material - Lower risk of affecting existing facilities and structures due the mechanical breaking method	- Lower production rate on excavation due to mechanical breaking method	Y
Mined Excavation with Drill and Blast	- Higher production rate on excavation by using explosive method	- More excavated materials due to hard to control of the overbreak - Higher risk of affecting existing facilities and structures due to the use and transportation of explosives	N

2.6 Tackling Environmental Challenges

2.6.1 General

2.6.1.1 Due consideration has been given in formulating the design of the Project to overcome environmental challenges encountered. The hierarchy of “Avoid, Minimise and Mitigate” has been adopted during the process to protect the environment as much as practicable. A summary of key actions adopted to tackle all the environmental challenges are discussed in the following sections.

2.6.2 Avoidance of Above Ground Works within Lam Tsuen Country Park

2.6.2.1 As discussed in Section 1.3, the existing Chamber G is an underground facility for distribution of raw water to NTM WTW, which is located within the underground stratum of Lam Tsuen Country Park. Mined excavation with drill and break methods are proposed for the modification works of Chamber G to avoid any above ground works within Lam Tsuen Country Park. Direct impacts on the natural resources in Lam Tsuen Country Park is avoided.

2.6.2.2 The fresh water trunk mains alignment between NTM WTW and NTM FWPSR will be located along the existing access road/ slope adjacent to existing access road, which is aligned immediately adjacent to the Lam Tsuen Country Park. Nevertheless, any encroachment on the Country Park is avoided.

2.6.3 Minimisation of Works within CA

2.6.3.1 The fresh water trunk mains between NTM WTW and NTM FWPSR, and water reserve area between Ching Yau Road and San Tam Road would encroach onto the CA. As discussed in Section 2.5.3, the proposed mainlaying works would be mainly located along the existing access road and water works reserve area/ slope adjacent to existing access road. The associated construction works would be minor excavation, mainlaying and backfilling. Moreover, no encroachment of any floral species of conservation importance is expected. Therefore, no significant ecological impact to the CA is anticipated.

2.6.4 Minimisation of Air Quality Impacts During Construction

2.6.4.1 The proposed fresh water trunk mains would be constructed by sub-sections and the works will be in small-scale. The modification works of Chamber G under this Project will be carried out underground.

2.6.4.2 Different standard dust suppression measures would be undertaken at the construction site. These measures include regular water spraying to suppress fugitive dust generation, covering exposed earth surface by tarpaulins as far as practicable, providing standard wheel washing facilities at the construction site exits, etc. These measures would help to alleviate the generation of fugitive dust during the construction period and hence minimise any impacts on the neighbouring sensitive areas.

2.6.4.3 Besides, the Contractor would be requested to avoid using exempted Non-Road Mobile Machines (NRMM) where practicable. Any use of exempted NRMM shall be fully justified by the Contractor and subject to agreement. The Contractor shall also use power supplied from power utilities when practicable.

2.6.4.4 By adopting such construction programme and design, the construction air quality impact is anticipated to be insignificant. More detailed descriptions are given in Section 3.

2.6.5 Minimisation of the Risk of Unauthorised Filling Activities

2.6.5.1 As part of the Project is adjoining a number of natural habitats, including CA and Lam Tsuen Country Park. Trip-ticket system should be adopted to monitor the disposal of C&D materials by contractor(s). Warning signs should be provided at the entrance of the proposed temporary and permanent vehicular access to deter any illegal dumping activities.

2.6.5.2 The currently proposed transportation routes of the C&D materials would include land transport to Tuen Mun Area 38 Fill Bank / Tseung Kwan O Area 137 Fill Bank and the West New Territories Landfill (WENT) / Chemical Waste Treatment Centre (CWTC). Proper management of the Contractors would be undertaken to minimise the risk of unauthorised filling activities.

2.7 Proposed Design for the Project

2.7.1 Construction Phase

2.7.1.1 Taking into account all the environmental constraints identified, engineering/operational requirements, and considerations of revised EIAO as discussed in Section 1.2, the Project has adopted the current design and the key elements are listed below and are shown in Figure 1.1:

· Laying of fresh water trunk mains, which encroach into boundary of the CA, between NTM WTW and NTM FWPSR, and Ching Yau Road and San Tam Road; and

· Modification of the Chamber G.

2.7.1.2 Descriptions of the design and construction of the above key elements are given in the following sections.

Laying of Fresh Water Trunk Mains

2.7.1.3 A total of 1km fresh water trunk mains with a diameter of 1,600mm will be laid between NTM WTW and NTM FWPSR, and Ching Yau Road and San Tam Road by open-cut method.

2.7.1.4 Typical construction sequence of open-cut method is given below:

- Site clearance;

- Excavation works;

- Laying of fresh water trunk mains; and

- Reinstatement.

Modification of Chamber G

2.7.1.5 The modification of Chamber G includes construction of a new combined access tunnel with portal, bypass tunnel and connection chambers for laying of raw water main from Muk Wu branch to NTM WTW and from Muk Wu branch to Tai Po Tau branch and from Tai Po Tau branch and Au Tau branch, and for providing access to the proposed Chambers G2, G3 and G4 (see Figure 1.1a).

2.7.1.6 The potential construction sequence of the modification works is given below:

· Mined excavation for access tunnel from Portal to Chamber G2;

· Mined excavation for bypass tunnel to Chamber G2;

· Construction of Chamber G2;

· Mined excavation for access tunnel from Chamber G2 to Chamber G3;

· Mined excavation for bypass tunnel to Chamber G3;

· Construction of Chamber G3;

· Mined excavation for access tunnel from Chamber G3 to G4; and

· Construction of Chamber G4.

2.7.1.7 Associated works to the modification of Chamber G, such as the construction of ventilation building for providing ventilation to the tunnels and connection chambers, portal for access to the tunnels and chambers and connection of raw water mains, are within the boundary of NTM WTW and outside the CA boundary, which would be assessed under separate Preliminary Environmental Review (PER).

2.7.1.8 Since the construction of jacking/launching pit and receiving pit for connection of raw water mains is located within the area of NTM WTW and outside CA, environmental assessment of the elements within NTM WTW, i.e. NTM WTW Extension including the above-ground excavation works for the modification works of Chamber G is included in PER. The PER also includes non-DP elements which are NTM WTW, NTM FWPSR, portal and ventilation building for Chamber G and the remaining water mains that does not encroach the boundary of CA.

2.7.2 Operational Phase

Fresh Water Trunk Mains

2.7.2.1 The fresh water trunk mains with diameter of 1,600mm would be laid between NTM WTW to NTM FWPSR, and Ching Yau Road and San Tam Road for delivering of treated water. The fresh water trunk mains would be operated by gravity system.

Chamber G

2.7.2.2 The modified Chamber G would include access tunnels and bypass tunnels to connect to the existing access tunnels and the NTM WTW to enhance flow hydraulics. The modified Chamber G will be operated full-time daily to transmit raw water to NTM WTW, Au Tau WTW and Tai Po Tau WTW.

2.8 Collating and Addressing Public Views

2.8.1 Engagement with Rural Committees

2.8.1.1 The Project Proponent arranged a discussion with the Ping Shan Rural Committee, Shap Pat Heung Rural Committee, Kam Tin Rural Committee and San Tin Rural Committee during December 2019 to March 2020.

2.8.1.2 During the discussion, concern regarding impact on traffic due to mainlaying works was expressed. Nevertheless, traffic impacts of the construction works of the Project will be minimised with the approved temporary traffic arrangement implemented so that the concern could be addressed.

2.8.2 Summary of Comments Received During the EIA Process

2.8.2.1 During the course of EIA study (including the exhibition of Project Profile), comments obtained from green groups and government’s advisory body have been duly revisited and were incorporated in the design, construction and operation of the Project where appropriate. Table 2.5 summarises the comments and the approaches adopted to address them suitably.

Table 2.5 – Summary of Approaches adopted to address Comments collated during EIA Process

Issue	Summary of Comments	Responses & Approaches Adopted
General	A detailed EIA should be conducted to comply with statutory requirements and any identified and potential environmental and ecological impacts and safety risk should be avoided, mitigated and/or compensated.	The EIA has been conducted according to the requirements as stipulated in the Study Brief (SB) (No.: ESB-333/2020) and the ecological survey has been conducted according to the approved methodology paper. The approaches taken to avoid, minimise and mitigate potential environmental impacts has been summarised in Section 2.6. In addition, as discussed in Section 2.5.7, mined excavation with drill and break methods are proposed for the proposed modification works of Chamber G. Drill and blast method which would pose potential risks related to hazard to the population in the NTM WTW and nearby villages is avoided.
Ecology	A more comprehensive ecological survey, especially for mammals and birds, should be conducted owing to the rich vegetation in the higher altitude in the valley of Ngau Tam Mei.	Ecological survey has been conducted for 6 months covering both wet and dry seasons (i.e. from January 2022 to June 2022) according to the requirement of a duration of at least 6 months as stated in the EIA SB and the methodology set out in the approved methodology paper. The survey has also included both mammal and bird surveys.
	As the proposed fresh water trunk mains will be laid across some natural streams, the design of the mains should avoid disturbance to the stream beds and banks and maintain their natural hydrology.	The alignment and level of proposed fresh water trunk mains would generally be following the existing fresh water trunk mains to avoid disturbance to the natural streams.
	Vegetation and trees should be properly protected from any construction works. Damages to roots, trunks and branches of trees should be avoided by proper positioning and alignment of proposed structures and fresh water trunk mains, and observing strictly the relevant guidelines for trees protection.	Development Bureau (DEVB) Technical Circular (TC) (W) No.4/2020 – Tree Preservation will be followed. Adequate tree protection measures shall be provided for the trees to be retained on site. Trees unavoidably affected by the Project shall be transplanted as far as practicable. Affected trees that are not suitable for transplantation and to be felled shall be compensated in not less than 1:1 in quantity (detailed in Section 10).
Water Quality	To comply with the “zero discharge policy” for Deep Bay and protect the ecology of Ramsar Site, any surface runoff generated from the Project from Ngau Tam Mei to Tan Kwai Tsuen during both construction and operation phase should be prevented from discharging into neighbouring river channels, stormwater drainage, fishponds and wetlands directly so as not to cause net increase in pollution load to Deep Bay.	Since the Project site is sited on OZP S/YL-NTM/13, there is no specific requirement for complying the “zero discharge policy’ for Deep Bay. However, the laying of fresh water trunk mains would be conducted section by section and water quality control measures, e.g. Best Management Practices (BMPs) as specified in Practice Note for Professional Persons on Construction Site drainage, EPD, 2023 (ProPECC PN 2/23) and practices outlined in ETWB TC (Works) No. 5/2005 “Protection of natural streams/rivers from adverse impacts arising from construction works”, would be implemented to protect the water quality of the nearby water (detailed in Section 5).
	Potential ground water drawdown and dewatering of stream courses within the Country Park and CA by tunnel construction of Chamber G should be avoided and mitigated against any impact upon the surface waters.	Ground water control measures are proposed for modification of Chamber G (detailed in Section 5), which include proper grouting and groundwater monitoring measures to be implemented during tunnel construction work to mitigate the potential ground water drawdown and dewatering of stream courses within the Country Park and CA as well as any indirect impact upon the surface waters.
Waste	The generation, transportation and disposal of solid wastes during construction should be under stricter control to prevent illegal and environmentally vandalistic dumping of wastes generated from the Project.	As discussed in Section 6, a trip‑ticket system in accordance with DEVB TCW No. 06/2010 would be implemented to ensure that the disposal of C&D materials is properly documented and verified and to avoid illegal dumping. A Waste Management Plan (WMP) will also be submitted to the Engineer for enforcement of site management measures during the construction phase.

2.9 Tentative Implementation Programme

2.9.1.1 A tentative programme for the construction of the Project is shown in Appendix 2.1. The construction works of this Project and E&M installation works under modification of Chamber G are scheduled to commence in Q1 of Year 2025 and completed by Q4 of Year 2030.

2.10 Concurrent Projects

2.10.1 Identified Concurrent Projects

2.10.1.1 A number of concurrent projects have been identified for the evaluation of any potential cumulative impacts during both construction and operational phases of the Project. A discussion of the potential environmental impacts on the preferred option caused by these concurrent projects is given below and their respective locations are shown in Figure 2.2.

Site Formation and Infrastructure Works for Public Housing Development at Sha Po, Shap Pat Heung and Tai Kei Leng, Yuen Long – Investigation, Design and Construction

2.10.1.2 The site formation and infrastructure works are located right next to the proposed mainlaying works of the Project along San Tam Road. (see Figure 2.2) The concurrent project involves site formation and infrastructure works for public housing development at Sha Po, Shap Pat Heung and Tai Kei Leng, and only that at Sha Po would be located within 500m assessment area of the Project. The construction works is anticipated to commence in Year 2026 and to be completed by Year 2031. Only the proposed fresh water trunk main laying works under this Project would be carried out in the vicinity of the concurrent project. The proposed mainlaying works of the Project would be carried out in sections and in small scale. The interface with the concurrent project is expected to be minor. The laying of fresh water trunk mains, involving excavation and backfilling between Ching Yau Road and San Tam Road, is expected to be concurrent with the proposed road works of San Tam Road under the proposed public housing development at Sha Po. However, close liaison with the corresponding parties of the concurrent project will be made to avoid overlapping works as far as possible during the overlapping period. Considering the small section of construction area of the fresh water trunk main laying works as well as the close liaison to coordinate overlapping of works, adverse cumulative environmental impacts with the Project are not anticipated.

Northern Link

2.10.1.3 A portion of the Northern Link interfaces with the proposed mainlaying works of the Project near Ching Yau Road and San Tam Road (see Figure 2.2). The concurrent project involves construction of MTR Northern Link. The construction works is anticipated to commence in Year 2025 and to be completed by Year 2034. Close liaison with the corresponding parties of the concurrent project will be made to avoid overlapping of dusty works as far as possible. Besides, only the proposed water main laying works under this Project would be carried out in the vicinity of the concurrent project and the local interface with the Project would be minor, adverse cumulative environmental impacts with the Project are therefore not anticipated. However, cumulative construction noise impacts have been addressed in Section 4.

Ngau Tam Mei Water Treatment Works (NTM WTW) Extension under PER

2.10.1.4 Ngau Tam Mei Water Treatment Works (NTM WTW) Extension are located adjacent to the mainlaying works, as well as the modification of Chamber G of the Project. The concurrent project involves extension works of NTM WTW and Ngau Tam Mei Fresh Water Primary Service Reservoir (NTM FWPSR) and laying of fresh water trunk mains from NTM WTW to existing fresh water distribution system near Tan Kwai Tsuen which does not encroach the boundary of CA. The construction works is anticipated to commence in Year 2024 and to be completed by Year 2030. Site formation works would be conducted for extension works of NTM WTW and NTM FWPSR of the concurrent project. Nevertheless, the proposed water main laying works under this Project would be carried out in sections and in small scale, while the modification of Chamber G under this Project would involve underground works only. Adverse cumulative environmental impacts with the Project are therefore not anticipated. However, cumulative construction noise impacts have been addressed in Section 4.

2.10.2 Summary of Concurrent Projects

2.10.2.1 A summary of the potential impacts of concurrent projects of the Project is given in Table 2.6. The potential cumulative environmental impacts from the concurrent projects would be further assessed in the relevant sections of this EIA report.

Table 2.6 – Potential cumulative impacts of concurrent projects

Concurrent Projects	Programme		Potential Cumulative Impacts
	Start	Complete	Construction Phase	Operational Phase
Site Formation and Infrastructure Works for Public Housing Developments at Sha Po, Shap Pat Heung and Tai Kei Leng, Yuen Long	2026	2031	Insignificant	Insignificant ^[1]
Northern Link	2025	2034	Construction noise	Insignificant ^[1]
NTM WTW Extension (under PER)	2024	2030	Construction noise	Insignificant ^[1]
Note: [1] Since the fresh water trunk mains would be operated by gravity system and Chamber G is located underground, no cumulative impact is expected during operation.

3 Air Quality Impact

3.1 Legislation, Standards and Criteria

3.1.1 General

3.1.1.1 The legislation, standards and guidelines that are relevant to the construction phase air quality impact assessment are identified, including, but not limited to, the following:

· Air Pollution Control Ordinance (APCO) (Cap. 311);

· Air Pollution Control (Construction Dust) Regulation (Cap. 311R);

· Air Pollution Control (Non-road Mobile Machinery) (Emission) Regulation (Cap. 311Z);

· Air Pollution Control (Fuel Restriction) Regulation (Cap. 311I); and

· Environmental Impact Assessment Ordinance (EIAO) (Cap. 499), Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM), Section 1 of Annex 4 and Annex 12.

3.1.2 Air Pollution Control Ordinance (APCO) (Cap. 311)

3.1.2.1 During the construction phase of the Project, the key air pollution sources that may bear upon the air quality are dust emissions associated with the construction activities of the Project. The representative pollutants for construction phase assessments are particulate matters, including Respirable Suspended Particulates (RSP) and Fine Suspended Particulates (FSP).

3.1.2.2 The principal legislation for controlling air pollutants is the Air Pollution Control Ordinance (APCO) (Cap. 311) which provides a statutory framework for establishing the Air Quality Objectives (AQOs) and stipulating the anti-pollution requirements for air pollution sources. The AQOs stipulate limits on concentrations for 7 pollutants including Sulphur Dioxide (SO₂), RSP, FSP, Nitrogen Dioxide (NO₂), Carbon Monoxide (CO), Ozone (O₃), and Lead (Pb). The current AQOs which took effect in January 2022 are listed in Table 3.1.

Table 3.1 – Hong Kong Air Quality Objectives (HKAQO)

Pollutant	Limits on Concentration, µg/m^3 ^[1] (The Number of Exceedance per calendar year allowed is shown in brackets)
	10-min	1-hr	8-hr	24-hr	Annual
SO2	500 (3)			50 (3)
RSP (PM10) ^[2]				100 (9)	50 (N.A.)
FSP (PM2.5) ^[3]				50 (35/18) ^[4]	25 (N.A.)
CO		30,000 (0)	10,000 (0)
NO2		200 (18)			40 (N.A.)
O3			160 (9)
Pb					0.5 (N.A.)
Notes: [1] All measurements of the concentration of gaseous air pollutants, i.e., sulphur dioxide, nitrogen dioxide, ozone and carbon monoxide, are to be adjusted to a reference temperature of 293Kelvin and a reference pressure of 101.325 kilopascal. [2] Respirable suspended particulates (RSP) means suspended particles in air with a nominal aerodynamic diameter of 10 μm or less (i.e. PM10). [3] Fine suspended particulates (FSP) means suspended particles in air with a nominal aerodynamic diameter of 2.5 μm or less (i.e. PM2.5). [4] On a best endeavour basis, a more stringent standard of 24-hour AQO for FSP at concentration level of 50 μg/m^3 and the number of allowable exceedances of 18 days per calendar year as the benchmark for conducting air quality impact assessments of new Government Projects.

3.1.3 Air Pollution Control (Construction Dust) Regulation (Cap. 311R)

3.1.3.1 The Air Pollution Control (Construction Dust) Regulation specifies processes that require special dust control. The Contractors are required to inform the Environmental Protection Department (EPD) and adopt proper dust suppression measures while carrying out “Notifiable Works” (which requires prior notification by the regulation) and “Regulatory Works” to meet the requirements as defined under the regulation.

3.1.4 Air Pollution Control (Non-road Mobile Machinery) (Emission) Regulation (Cap. 311Z)

3.1.4.1 Air Pollution Control (Non-road Mobile Machinery) (Emission) Regulation specifies that all Non-road Mobile Machinery (NRMMs), except for those exempted, used in specified activities and locations including construction sites, container terminals and back up facilities, restricted areas of the airport, designated waste disposal facilities and specified processes are required to comply with the prescribed emission standards.

3.1.5 Air Pollution Control (Fuel Restriction) Regulation (Cap. 311I)

3.1.5.1 Air Pollution Control (Fuel Restriction) Regulation controls the types of fuel allowed for use and their sulphur contents in commercial and industrial processes to reduce SO₂ emissions.

3.1.6 Environmental Impact Assessment Ordinance (EIAO) (Cap. 499) and Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM)

3.1.6.1 The criteria stipulated in Annex 4 of the EIAO-TM is adopted for evaluating the air quality impacts associated with the Project.

3.2 Description of the Environment

3.2.1 Existing Ambient Air Quality

3.2.1.1 The nearest Air Quality Monitoring Station (AQMS) operated by EPD to the Project is Yuen Long AQMS. The latest 5-years monitoring data for RSP and FSP are summarised in Table 3.2.

Table 3.2 – Air quality monitoring data (Yuen Long Station, 2018 – 2022)

Pollutant	Parameter	Concentrations (μg/m^3)						AQOs (μg/m^3)
		2018	2019	2020	2021	2022	5-year mean
RSP	10^th highest 24-hour	75	83	77	73	56	73 [73%]	100 (9)
	Annual	37	37	30	30	25	32 [64%]	50
FSP	19^th highest 24-hour	41	38	33	36	38	37 [74%]	50 (18)
	Annual	20	20	16	17	16	18 [71%]	25
Notes: [2] Monitoring results exceeded the AQOs are shown as bolded and underlined characters. [3] Number of exceedances allowed against AQOs is shown in ( ) while % of AQOs is provided in [ ]. The 5-year mean is the average of the corresponding pollutant concentrations from Year 2018 to 2022.

3.2.1.2 The 10^th highest daily RSP concentrations ranged from 56µg/m³ in Year 2022 to 83µg/m³ in Year 2019. All the 10^th highest daily RSP concentrations complied with the AQOs of 100µg/m³. A decreasing trend for annual RSP concentration was observed, which declined from 37µg/m³ in Year 2018 to 25µg/m³ in Year 2022. All the annual RSP concentrations complied with the AQOs of 50μg/m³.

3.2.1.3 The 19^th highest daily FSP concentrations ranged from 33µg/m³ in Year 2020 to 41µg/m³ in Year 2018. All the 19^th highest daily FSP concentrations complied with the AQOs of 50µg/m³. Annual FSP concentrations ranged from 16μg/m³ in Year 2020 and Year 2022 to 20μg/m³ in Year 2018 and Year 2019. All the annual FSP complied with AQOs of 25μg/m³.

3.2.2 Future Background Air Quality

3.2.2.1 It should be noted that the ambient air quality conditions described in the above sections are based on the historical monitoring data only. In order to predict the future ambient air quality taking into account the emission reduction plan for Pearl River Delta (PRD) region, PATH v3.0 (Pollutants in the Atmosphere and their Transport over Hong Kong), a regional air quality model, been developed by EPD to simulate the future background air quality in Hong Kong.

3.2.2.2 Since the construction period for this Project is from Year 2025 to Year 2030, the future ambient air quality for Year 2025 and Year 2030 are presented. The assessment area of the Project involves 11 grids in PATH v3.0 as shown in Figure 3.1 and are summarised in the following Table 3.3.

Table 3.3(a) – Future ambient air quality for concerned PATH grids (Year 2025)

PATH Grid	Pollutant Concentrations (μg/m^3)
	RSP		FSP
	10^th highest 24-hour	Annual	19^th highest 24-hour	Annual
28_49	56	21	34	13
28_50	60	23	36	14
29_49	57	21	34	13
29_50	60	23	37	14
30_49	57	21	34	13
30_50	59	22	36	14
30_51	57	22	35	14
31_49	57	22	35	13
31_50	58	22	35	14
31_51	58	22	35	14
32_50	59	22	35	14
AQOs (μg/m^3)	100 (9)	50	50 (18)	25

Table 3.3(b) – Future ambient air quality for concerned PATH grids (Year 2030)

PATH Grid	Pollutant Concentrations (μg/m^3)
	RSP		FSP
	10^th highest 24-hour	Annual	19^th highest 24-hour	Annual
28_49	51	20	30	12
28_50	54	21	32	13
29_49	51	20	30	12
29_50	54	21	33	13
30_49	52	20	30	12
30_50	53	20	32	13
30_51	51	20	31	12
31_49	52	20	30	12
31_50	52	20	31	12
31_51	51	20	31	12
32_50	52	20	31	13
AQOs (μg/m^3)	100 (9)	50	50 (18)	25

3.2.2.3 With the updated emission inventory and implementation of the emission reduction measures by both the Hong Kong and Guangdong Governments, future background RSP and FSP concentrations predicted by PATH v3.0 is in general lower than the existing monitoring data and all could be well within the AQOs.

3.3 Representative Air Sensitive Receivers

3.3.1.1 In accordance with Annex 12 of the EIAO-TM, Air Sensitive Receivers (ASRs) include domestic premises, hotel, hostel, hospital, clinic, nursery, temporary housing accommodation, school, educational institution, office, factory, shop, shopping centre, place of public worship, library, court of law, sports stadium or performing arts centre. Any other premises or places with which, in terms of duration or number of people affected, has a similar sensitivity to the air pollutants as the aforelisted premises and places would also be considered as a sensitive receiver.

3.3.1.2 Representative ASRs, that are located closest to the Project, i.e. within the first layer, within a distance of 500m from the boundary of the Project and any associated works have been identified as they are most affected. Existing ASRs are identified by means of reviewing topographic maps, aerial photos and building plans, and verified by site visits. Planned/committed ASRs are identified by making reference to relevant Outline Zoning Plans (OZP) (OZP No. S/YL-NTM/13, S/YL-MP7, S/YL-KTN/11 and S/YL-NSW/9), S.16 / S.12a Town Planning Ordinance Development Permission Area Plans, Outline Development Plans (ODP), Layout Plans and other relevant published land use plans, including plans and drawings published by the Lands Department and any land use and development applications approved by Town Planning Board in the vicinity of the Project. No representative planned/committed ASRs are identified within the first layer to the Project.

3.3.1.3 The locations of representative existing ASRs are summarised in Table 3.4 and are shown in Figure 3.1

Table 3.4 – Representative ASRs

ASR ID	Location	Land Use ^[2]	Approx. distance from the Project (m)
NTMA1	Village House at Ngau Tam Mei	R	~350
NTMA2	Village House at Ngau Tam Mei	R	~50
NTMA3	Village House at Ngau Tam Mei	R	~90
NTMA4	Village House at Ngau Tam Mei	R	~55
NTMA5	Village House at Ngau Tam Mei	R	~110
NTMA6	Village House at Ngau Tam Mei	R	~260
SWA1	San Wai Village	R	~470
SWA2	San Wai Village	R	~40
SWA3	Office in San Wai Village	C	~40
SWA4	San Wai Village	R	~15
LH1	Village House in Long Ha Tsuen	R	~15
KPRA1	Houses by Kam Pok Road East	R	~370
MGA1	Merry Garden	R	~460
Notes: [1] ASR locations are determined based on-site survey and building plan where available and applicable. [2] R – Residential, C – Commercial.

3.4 Identification and Evaluation of Impacts during Construction Phase

3.4.1 Identification of Project-Induced Pollution Sources

3.4.1.1 As discussed in Section 2.7, the key elements of the Project include the following:

· Laying of fresh water trunk mains, which encroach into boundary of the CA, between Ngau Tam Mei Water Treatment Works (NTM WTW) and Ngau Tam Mei Fresh Water Primary Service Reservoir (NTM FWPSR), and Ching Yau Road and San Tam Road; and

· Modification of the Chamber G.

3.4.1.2 The major project-induced pollution source that may potentially affect air quality during the construction phase is dust emission associated with construction activities, which include the following:

· Excavation and backfilling for laying of fresh water trunk mains; and

· Mined excavation with drill and break works for modification works of Chamber G;

3.4.1.3 Besides, gaseous emission from fuel combustion from the use of Powered Mechanical Equipment (PME) during construction works would also be a source of air pollution.

3.4.2 Evaluation of Construction Dust Impact

Laying of Fresh Water Trunk Mains

3.4.2.1 The construction of about 1km fresh water trunk mains involves open-cut method. The associated works, i.e. excavation and backfilling for fresh water trunk main laying at open trench, would have the potential to generate fugitive dust.

3.4.2.2 The fresh water trunk main laying works would be constructed by sections along the alignment. Each section would be divided into sub-sections of approximately 30m long and 3m wide, with excavation works expected to complete within 1 month for each sub-section. The proposed fresh water trunk mains between NTM WTW and NTW FWPSR would mainly be laid along existing road or on slope adjacent to the existing access road, while that between Ching Yau Road and San Tam Road would be along existing waterworks reserve area. Neither major site formation nor extensive excavation works would be required. The fresh water trunk mains would be prefabricated as far as practicable to further minimise the construction dust impact on-site. Therefore, the works site will be limited in size and the fugitive dust impacts are anticipated to be short-term and localised. For backfilling works, fugitive dust emissions will be reduced by compacting the filled area immediately after backfilling and covered by impervious sheet when it is not in use. With the implementation of procedures and requirements given in the Air Pollution Control (Construction Dust) Regulation and good site practice as detailed in Section 3.5.1, dust emission from the construction works would be reduced as far as practicable and adverse air quality impacts on the identified representative ASRs are not anticipated during the construction phase.

Modification Works for Chamber G

3.4.2.3 The modification works for Chamber G which would be underground works under this Project involve construction of tunnels / chambers using mined excavation with drill and break method respectively. The tunnels / chambers would be conducted by sections. In addition, water spraying would be conducted during the mined excavation with drill and break construction works. The maximum excavation volume produced is around 220m³ per day. According to an average truck capacity of 7m³, the maximum number of trips for the underground works of modification of Chamber G is around 4 to 5 trips per working hour. Therefore, the dusty activities for construction of tunnels / chambers are considered as small scale. For the underground construction working areas, mitigation measures are proposed to reduce the potential dust emissions from the portal exhaust at the entrance of proposed portal of Chamber G such as installing dust filter system with a dust removal efficiency of 95% or above at the exhaust of the tunnel. The above-ground construction and mucking-out operation for Chamber G is within the boundary of NTM WTW and hence, the dust impacts generated from them is covered in PER. Since the portal would be the only access/egress to the underground construction area, and the door would only be opened when necessary as well as dust filter will be installed at the exhaust louver and the truck exit will be washed regularly, it is anticipated that adverse dust impact will be minimal as the dust would be filtered before exiting the portal entrance. Adverse air quality impacts on the identified representative ASRs are therefore not anticipated during the construction phase.

3.4.3 Evaluation of Air Quality Impact from Fuel Combustion

3.4.3.1 Gaseous emission, i.e. NO₂, SO₂ and CO, is anticipated from the use of PME during construction works. Emissions from machines and non-road vehicles are controlled by the Air Pollution Control (Non-road Mobile Machinery) (Emission) Regulation. Starting from 1st December 2015, only approved or exempted non-road mobile machinery is allowed to be used in construction sites. Ultra-low sulphur diesel (ULSD) with a sulphur content of not more than 0.005% by weight and a viscosity of not more than 6 centistokes at 40^oC will be used as much as practicable to minimise SO₂ emissions. The introduction of ULSD for vehicle fleet and implementation of the Air Pollution Control (Fuel Restriction) Regulations have also reduced the SO₂ emission from road transport and fuel combustion in Hong Kong. Besides, good site practices have also been recommended and implemented to control and reduce the emission from the use of non-road mobile machinery from the Project (see Section 3.5.2). Hence, the emissions from non-road mobile machinery are considered relatively small and the associated emission is considered insignificant during the construction phase of the Project.

3.4.4 Potential Cumulative Impacts from Concurrent Construction Projects

3.4.4.1 All potential concurrent projects have been identified and the construction programme of the Project are described in Section 2. The potential cumulative construction dust impacts, if any, are discussed below.

Site Formation and Infrastructure Works for Public Housing Development at Sha Po, Shap Pat Heung and Tai Kei Leng, Yuen Long – Investigation, Design and Construction

3.4.4.2 Potential fugitive dust impact is expected during the construction phase of the project, Site Formation and Infrastructure Works for Public Housing Development at Sha Po, Shap Pat Heung and Tai Kei Leng, Yuen Long – Investigation, Design and Construction. The concurrent project is expected to commence in 2026 and complete in 2031. The public housing development at Sha Po would be located within 500m assessment area of the Project, while that at Shap Pat Heung and Tai Kei Leng would be outside of the assessment area, and therefore would not be considered nor discussed.

Public Housing Development at Sha Po

3.4.4.3 The location of laying of fresh water trunk mains, involving excavation and backfilling works, between Ching Yau Road and San Tam Road, is expected to overlap with the proposed road works of San Tam Road under the proposed public housing development at Sha Po. The location of the proposed road works for the public housing development at Sha Po is approximately 300m away from the laying of fresh water trunk mains, while the nearest ASR (i.e. MGA1) to the concurrent project is approximately 60m. Only the proposed fresh water trunk main laying works under this Project would be carried out in the vicinity of the proposed road works of the public housing site. Both the concurrent project and the proposed fresh water trunk main laying works of the Project would be carried out in small scale and the proposed fresh water trunk main laying works under this Project would be carried out in sections. Therefore, the interface with the concurrent project is expected to be minor. Hence, the potential cumulative air quality impact from this road work and the Project is expected to be not adverse.

MTR Northern Link

3.4.4.4 The development of MTR Northern Link is in the vicinity of the Project and may generate cumulative dust impact. It is expected to commence in 2025 and complete by 2034. While most of the construction works for the MTR Northern Link would be carried out underground, Ngau Tam Mei Depot and Long Ha Tsuen Ancillary Building will be constructed aboveground within the 500m assessment area of the laying of fresh water trunk main.

Ngau Tam Mei Depot

3.4.4.5 The site boundary is approximately 250m from the proposed fresh water trunk main laying location and 40m from the nearest ASR (i.e. SWA1). Close liaison with the corresponding parties of the concurrent project will be made to avoid the overlapping of dusty works as far as possible. Besides, the construction of Ngau Tam Mei Depot involve excavation works while the laying of fresh water trunk mains will be carried out in sections and in small scale, the interface with the Project would be minor. Moreover, it is anticipated that they will also implement all the best practices to abate air quality impacts where practicable and fulfil the criteria of EIAO-TM under its own EIA Study. In addition, the nearest separation distance between the Ngau Tam Mei Depot and the Project is about 250m. Therefore, adverse cumulative air quality impact is not anticipated with implementation of control measures for both projects.

Long Ha Tsuen Ancillary Building

3.4.4.6 The nearest ancillary building is approximately 135m and 150m from the nearest fresh water trunk mains location and the nearest ASR (i.e. LH1) respectively. However, both the fresh water trunk mains and the ancillary building involve only small scale of works. Besides, close liaison with the corresponding parties of the concurrent project will be made to avoid the overlapping of dusty works as far as possible during the overlapping period. Considering the small scale of works and the nearest distance between the ancillary building and the Project is 135m, it is anticipated that they will also implement all the best practices to abate air quality impacts where practicable, adverse cumulative air quality impacts with this concurrent project are therefore not anticipated.

Ngau Tam Mei Water Treatment Works Extension

3.4.4.7 Potential air quality impact is expected during the construction phase of the Ngau Tam Mei Water Treatment Works Extension under PER. It is expected to commence in 2024 and complete by 2030. NTM WTW and NTM FWPSR extension, and proposed fresh water trunk main of this extension works project would be located within 500m assessment area of the laying of fresh water trunk main and modification of Chamber G under this Project.

Ngau Tam Mei Water Treatment Works (NTM WTW) Extension

3.4.4.8 The proposed extension works of NTM WTW would be conducted in sub-workfronts with maximum works area at a time of 5,000 m² while no major earthworks or site formation works would be required. The site boundary of NTM WTW is adjacent to the proposed fresh water trunk main laying between NTM WTW and NTM FWPSR, as well as the modification of Chamber G, and the nearest ASR (i.e. NTMA1) is located around 40m from the site boundary. There would be temporary stockpiling area for the works within NTM WTW by assuming the excavated materials would be stored at the active workfront during the excavation or earthwork period. The excavated material from Chamber G would also be temporary stored within the boundary of NTM WTW. Site formation works would be conducted for the extension works of NTM WTW within the existing site boundary. Close liaison with the corresponding parties of the concurrent project will be made to avoid the overlapping dusty works as far as possible during the overlapping period. Mitigation measures for dust generation of NTM WTW extension works would be implemented to reduce the cumulative impact with this Project. For instance, vehicle washing facilities would be provided at every designated vehicle exit point where practicable and any excavated dusty material would be covered entirely by sheeting or sprayed with water. Nevertheless, the proposed fresh water trunk main laying works under this Project would be carried out in sections and in small scale, while the modification of Chamber G under this Project would involve underground works only. The portal exhaust is located within the site boundary of the proposed extension works of NTM WTW. Open stockpiling would also be covered or avoided to minimise the dust impact to the nearby ASR. For the underground construction works, some mitigation measures are proposed to reduce the potential dust emissions from the portal exhaust at the entrance of the existing access tunnel such as installing dust filter system at the portal exhaust of the tunnel. In addition, water spraying will be conducted during the mined excavation with drill and break construction works. Therefore, the interface with the concurrent project is expected to be minor. The cumulative air quality impact is not anticipated to be adverse with control measures in place for both projects.

Ngau Tam Mei Fresh Water Primary Service Reservoir (NTM FWPSR) Extension

3.4.4.9 The proposed extension works of NTM FWPSR would be conducted in sub-workfronts with maximum works area at a time of 5,000 m² while no major earthworks or site formation works would be required. The site boundary of NTM FWPSR is approximately 150m away from the proposed water main laying between NTM WTW and NTM FWPSR and the nearest ASR (i.e. NTMA5) is located around 160m from the site boundary. There would be temporary stockpiling area for the works within NTM FWPSR and the excavated materials would only be temporary stored at the active workfront during the excavation or earthwork period within NTM FWPSR. Site clearance, foundation and superstructure works would be conducted for the extension works of NTM FWPSR within the existing site boundary. Close liaison with the corresponding parties of the concurrent project will be made to avoid the overlapping dusty works as far as possible during the overlapping period. Moreover, open stockpiling would be covered or avoided to minimise the dust impact to the nearby ASR. Nevertheless, the proposed fresh water trunk main laying works under this Project would be carried out in sections and in small scale. Therefore, the interface with the concurrent project is expected to be minor. The cumulative air quality impact is not anticipated to be adverse with control measures in place for both projects.

Fresh Water Trunk Mains

3.4.4.10 The fresh water trunk mains of the concurrent project which are outside the CA zone are connected to the proposed fresh water trunk mains of this Project, and will be under the same construction contract. There would be temporary stockpiling area for the fresh water trunk main laying which the excavated materials would be temporary stored along the access road within the works area of fresh water trunk main laying works. The fresh water trunk main laying works would be constructed by sections along the alignment as discussed in Section 3.4.2.2 and each section would be separated by a distance of at least 250m to avoid any cumulative impact as far as practicable. Moreover, open stockpiling area would be covered or avoided to minimise the cumulative dust impact. With the implementation of control measures, such as good site practices, cumulative air quality impact during the construction stage is therefore considered to be not adverse.

3.5 Good Site Practice & Recommended Mitigation Measures

3.5.1 Construction Dust Control

3.5.1.1 The control measures given in the Air Pollution Control (Construction Dust) Regulation and good site practice as follows should be implemented to reduce dust nuisance:

· Any excavated or stockpile of dusty material should be covered entirely by impervious sheeting or sprayed with water to maintain the entire surface wet and then removed or backfilled or reinstated where practicable for the excavation or unloading;

· Any dusty materials remaining after a stockpile is removed should be wetted with water and cleared from the surface of roads;

· A stockpile of dusty material should not be extended beyond the pedestrian barriers, fencing or traffic cones;

· The load of dusty materials on a vehicle leaving a construction site should be covered entirely by impervious sheeting to ensure that the dusty materials do not leak from the vehicle;

· The portion of any road leading only to the construction site that is within 30m of a vehicle entrance or exit should be kept clear of dusty materials;

· Surfaces where any pneumatic or power-driven drilling, cutting, polishing or other mechanical breaking operation takes place should be sprayed with water or a dust suppression chemical continuously;

· Any area that involves demolition activities should be sprayed with water or a dust suppression chemical immediately prior to, during and immediately after the activities so as to maintain the entire surface wet;

· Any skip hoist for material transport should be totally enclosed by impervious sheeting;

· Every stock of more than 20 bags of cement or dry pulverised fuel ash (PFA) should be covered entirely by impervious sheeting or placed in an area sheltered on the top and the three sides;

· Cement or dry PFA delivered in bulk should be stored in a closed silo fitted with an audible high-level alarm which is interlocked with the material filling line and no overfilling is allowed;

· Loading, unloading, transfer, handling or storage of bulk cement or dry PFA should be carried out in a totally enclosed system or facility, and any vent or exhaust should be fitted with an effective fabric filter or equivalent air pollution control system;

· Exposed earth should be properly treated by compaction, turfing, hydroseeding, vegetation planting or sealing with latex, vinyl, bitumen, shotcrete or other suitable surface stabilisers within six months after the last construction activity on the construction site or part of the construction site where the exposed earth lies; and

· Dust filter will be installed at the portal exhaust at the entrance of the access tunnel.

3.5.2 Emission control on NRMMs

3.5.2.1 Fuel combustion from the use of PME during construction works would be a source of air emission. To improve air quality, EPD has introduced the Air Pollution Control (NRMMs) (Emission) Regulation, which came into operation in 2015 to regulate emissions from machines and non-road vehicles. Under the Regulation, NRMMs, except those exempted, are required to comply with the prescribed emission standards. All regulated machines sold or leased for use in Hong Kong must be approved or exempted with a proper label in a prescribed format issued by EPD. Only approved or exempted NRMMs with a proper label are allowed to be used in specified activities and locations including construction sites.

3.5.2.2 In addition, the following good site practices that can control and reduce the emission from the use of non-road mobile machinery from the Project are recommended:

· Regulated machines shall be used and exempted NRMMs should be avoided where practicable;

· Use cleaner fuel such as ULSD in diesel-operated construction plant to reduce sulphur dioxide emission;

· Use of electric PMEs where practicable;

· Use power supplied from power utilities when practicable (e.g. to replace generators);

· Switch off the engine of PMEs when idling;

· Implement regular and proper maintenance for plant and equipment;

· Employ plant and equipment of adequate size and power output and avoid overloading of the plant;

· Locate the PMEs away from sensitive receivers as far as possible; and

· Erect screen to shield the emission source from sensitive receivers where necessary and practicable.

3.6 Identification and Evaluation of Impacts during Operational Phase

3.6.1.1 The fresh water trunk mains and Chamber G are mainly underground pipelines and access tunnels. No adverse air quality impact during the operation of the Project is anticipated.

3.7 Residual Impacts

3.7.1.1 No adverse residual impact is anticipated from the construction and operational phases of the Project with the implementation of good site practices and recommended mitigation measures.

3.8 Conclusion

3.8.1.1 The key air pollution sources in association with the Project have been identified and the potential construction air quality impact has been evaluated. For the laying of fresh water trunk mains, the works would be constructed by sections along the alignment in small scale, so the fugitive dust impact is anticipated to be short-term and localised. For the modification works for Chamber G, only underground works would be involved under this Project and no adverse air quality impact is anticipated. With the implementation of the mitigation measures as stipulated in the Air Pollution Control (Construction Dust) Regulation, Air Pollution Control (Non-road Mobile Machinery) (Emission) Regulation, Air Pollution Control (Fuel Restriction) Regulation, dust control measures, including watering once per hour on exposed construction areas with dust emission, and good site practices, no adverse construction air quality impact is anticipated.

4 Noise Impact

4.1 Relevant Legislation, Standards and Criteria

4.1.1 General

4.1.1.1 The relevant legislation applicable to present the study for the assessment of noise impacts include:

· Noise Control Ordinance (NCO) (Cap.400);

· Technical Memorandum on Noise from Construction Work other than Percussive Piling (GW-TM);

· Technical Memorandum on Noise on Construction Work in Designated Areas (DA-TM);

· Technical Memorandum for the Assessment of Noise from Places other than Domestic Premises, Public Places or Construction Sites (IND-TM); and

· Environmental Impact Assessment Ordinance (EIAO) (Cap. 499) and EIAO-TM.

4.1.2 Construction Noise

Airborne Construction Noise During Normal Hours

4.1.2.1 The NCO provides the statutory framework for noise control in Hong Kong. Assessment procedures and standards are set out in the respective TM promulgated under NCO.

4.1.2.2 For construction, there is no statutory limit on construction noise during normal hours under the NCO and related TMs. There is statutory control on construction noise between the hours 1900 and 0700 from Monday to Saturday and at any time on general holidays (including Sundays) under the NCO. To ensure a better environment, the EIAO-TM promulgated under the EIAO has imposed more stringent criteria. Daytime general construction works (excluding percussive piling) between the hours 0700 and 1900 on weekdays, i.e. non-restricted hours, is controlled under the EIAO. The EIAO-TM stipulates criteria of 65 – 75dB(A) for daytime construction activities, as shown in Table 4.1.

4.1.2.3 In addition, reference has been made to EIAO Guidance Note No. 9/2023 on “Preparation of Construction Noise Impact Assessment under the Environmental Impact Assessment Ordinance”.

Table 4.1 – Noise standards for daytime construction activities

Uses	Noise Standards^[1], ^[2], Leq (30min) dB(A)
	0700 to 1900 hours on any day not being a Sunday or general holiday
· All domestic premises · Temporary housing accommodation · Hostels · Convalescent homes, and · Homes for the aged	75
· Places of public worship · Courts of law, and · Hospitals and medical clinics	70
Educational institutions (including kindergartens and nurseries)	70 65 (During examination)
Notes: [1] The above standards apply to uses which rely on opened windows for ventilation and are assessed at 1m from the external façade. [2] A Construction Noise Permit shall be required for carrying out relevant construction work during restricted hours under the NCO. In case the applicant would like to evaluate whether carrying out relevant construction works during restricted hours under the NCO is feasible or not in the contact of programming construction works, reference should be made to relevant technical memoranda issued under the NCO.

Airborne Construction Noise during Restricted Hours

4.1.2.4 The NCO also provides statutory control on general construction works during restricted hours (i.e. 1900 to 0700 hours (of the next day) from Monday to Saturday and at any time on Sundays or public holidays). The use of Powered Mechanical Equipment (PME) for construction works during restricted hours will require a Construction Noise Permit (CNP). The GW-TM details the procedures adopted by Noise Control Authority (NCA) for assessing such application. The granting of a CNP is subject to conditions stated in the CNP and it may be revoked at any time for failure to comply with the permit conditions.

4.1.2.5 In addition to the general controls on the use of PME during restricted hours, the details and guidelines for the use of Specified Powered Mechanical Equipment (SPME) and the undertaking of Prescribed Construction Work (PCW) during the restricted hours in a designated area are stipulated in the DA-TM. Construction plant or equipment classified as SPME under the DA-TM includes hand-held breakers, bulldozers, concrete lorry mixers, dump trucks and vibratory pokers. The PCW includes the erection or dismantling of formwork or scaffolding, hammering, and loading, unloading or handling of rubble, wooden boards, steel bars, wood or scaffolding material.

4.1.2.6 The DA-TM details the procedures that should generally be adopted by the NCA Authority for assessing the use of SPME during restricted hours and for determining whether a CNP will be issued.

4.1.2.7 Maximum noise levels from construction activities during restricted hours at affected Noise Sensitive Receivers (NSRs) are controlled under the TMs and shall generally not exceed the specified Acceptable Noise Levels (ANLs). These ANLs are obtained with corrections for the duration of the CNP and multiple permit situations, if applicable, to the Basic Noise Levels (BNLs). The BNLs are stipulated in accordance with the Area Sensitivity Ratings established for the NSRs. The BNLs for construction works in Designated Areas are more stringent than those given in the GW-TM and summarised in Table 4.2.

Table 4.2 – BNLs for construction during restricted hours

Time Period	BNLs for Area Sensitive Ratings^[1], dB(A)
	A	B	C
All days during the evening (1900 to 2300 hours), and general holidays (including Sundays) during the day and evening (0700 to 2300 hours)	60 (45)	65 (50)	70 (55)
All days during the night-time (2300 to 0700 hours)	45 (30)	50 (35)	55 (40)
Note: [1] Figures in brackets are BNLs for SPME construction work in designated areas.

4.1.2.8 According to the current construction programme, the proposed construction works will be carried out during non-restricted hours only. However, in case of any construction activities during restricted hours, the Contractor will be responsible to ensure compliance with the CNP and the relevant TMs under the NCO. The Contractor will be required to submit a CNP application to the NCA and abide by any conditions as stated in the CNP, should one be issued. Regardless of the results of construction noise impact assessment in this EIA study, the NCA will process the CNP application, if necessary, based on the NCO, the relevant technical memoranda issued under the NCO, and the contemporary conditions/ situations.

4.1.2.9 As defined in the Noise Control Designated Area Plan No. EPD/AN/NT-01, Chamber G is not within the Designated Area. However, construction work for parts of the fresh water trunk mains will fall into the Designated Areas in Long Ha.

4.1.2.10 Despite any description made in this Environmental Impact Assessment (EIA), the issue of CNP for the project construction is subject to the decision of the Noise Control Authority. The Noise Control Authority will consider a well-justified CNP application, once filed, for construction works within restricted hours as guided by the relevant TMs issued under the NCO. The Noise Control Authority will take into account contemporary conditions / situations of adjoining land uses and any previous complaints against construction activities at the site before making a decision in granting a CNP. Nothing in the report shall bind the Noise Control Authority in making a decision. If a CNP is to be issued, the Noise Control Authority shall include in it any conditions demand. Failure to comply with any such conditions will lead to cancellation of the CNP and prosecution under the NCO.

Groundborne Construction Noise during Normal Hours

4.1.2.11 Noise arising from general construction works that may generate groundborne noise during normal working hours is governed by the EIAO-TM under the EIAO. The IND-TM under the NCO stipulates that noise transmitted primarily through the structural elements of building, or buildings, shall be 10 dB(A) less than the relevant ANLs.

4.1.2.12 Based on the same principle for the groundborne noise criteria (i.e. ANL-10 dB(A) under the IND-TM), the groundborne construction noise levels inside domestic premises and schools shall be limited to 65 dB(A) and 60 dB(A) respectively when compared to the EIAO-TM. A summary of groundborne construction noise criteria during normal working days is given in Table 4.3.

Table 4.3 – Groundborne construction noise criteria

NSR type	Noise Criteria, dB(A)
	0700 to 1900 hours on any day not being a Sunday or general holiday
· All domestic premises · Temporary housing accommodation · Hostels · Convalescent homes, and · Homes for the aged	65
· Places of public worship · Courts of law, and · Hospitals and medical clinics	60
Educational institutions (including kindergartens and nurseries)	60 55 (for during examination)

Groundborne Construction Noise During Restricted Hours

4.1.2.13 Similar to airborne construction noise during restricted hours, NCO also provides statutory control of construction work for goundborne noise during restricted hours. As discussed in the above section, same principle for groundborne noise criteria (i.e. ANL-10dB(A) under the IND-TM) shall be adopted. Therefore, Table 4.4 below summarizes the groundborne construction noise criteria during restricted hours.

Table 4.4 – Construction groundborne noise criteria during restricted hours

Time Period	Noise Criteria, dB(A) for Area Sensitivity Ratings, dB(A)
	A	B	C
All days during the evening (1900 to 2300 hours), and general holidays (including Sundays) during the day and evening (0700 to 2300 hours)	50	55	60
All days during the night-time (2300 to 0700 hours)	35	40	45

4.1.3 Operational Noise

Fixed Noise Sources

4.1.3.1 Operational noise from fixed noise sources is controlled under the IND-TM. To plan for a better environment, the EIAO-TM has specified the following requirements for the planned fixed noise sources, whichever is more stringent:

· 5dB(A) below the appropriate ANLs in the IND-TM; or

· the prevailing background noise levels.

4.1.3.2 The ANLs for different Area Sensitivity Ratings during different periods are summarised in the following Table 4.5.

4.1.3.3 Besides, ANL stipulated in the IND-TM will be adopted in the evaluation of potential cumulative fixed noise sources impact assessment from existing and planned fixed noise sources.

Table 4.5 – ANLs for fixed noise sources

Time Period	ANL, dB(A)
	Area Sensitivity Rating A	Area Sensitivity Rating B	Area Sensitivity Rating C
Day (0700 to 1900 hours)	60	65	70
Evening (1900 to 2300 hours)	60	65	70
Night (2300 to 0700 hours)	50	55	60

4.1.3.4 As mentioned in Section 2, the DP elements of modification of Chamber G under this EIA will only include the construction of access tunnels and bypass tunnels which is within Lam Tsuen Country Park and Conservation Area (CA). The remaining modification works of Chamber G such as the ventilation building and tunnel portal falling within the area of Ngau Tam Mei Water Treatments Works (NTM WTW) that are outside Lam Tsuen Country Park and CA are considered non-DP elements. The environmental impacts of the non-DP elements will be addressed in a separate Preliminary Environmental Review (PER).

4.1.3.5 In addition, according to the latest engineering design of the fresh water trunk mains, water pumps will not be required. As there are no planned fixed noise sources for the DP elements under this EIA, operational noise impacts from planned fixed noise sources are therefore not anticipated.

4.1.3.6 In accordance with Clause 1.2 of Appendix C of the EIA Study Brief, prevailing background noise surveys shall be conducted to determine the standards for fixed noise source assessment. However, given that there are no planned fixed noise sources under the DP elements of this EIA, prevailing background noise surveys will not be necessary.

4.2 Baseline Conditions

4.2.1 Description of Existing Environment

4.2.1.1 The Project will involve modification works of Chamber G located near NTM WTW and within Lam Tsuen Country Park and CA and construction of two sections of fresh water trunk mains which partially encroach into boundary of the CA, between NTM WTW and Ngau Tam Mei Fresh Water Primary Service Reservoir (NTM FWPSR), and Ching Yau Road and San Tam Road.

4.2.1.2 Chamber G is an underground structure located to the southeast of NTM WTW and above it is mainly vegetated areas. The surrounding of the fresh water trunk mains is mainly rural which consists of vegetation, village houses and temporary structures. The noise climate near both Chamber G and the proposed fresh water trunk mains is tranquil.

4.2.2 Existing and Planned Noise Sources

Existing Noise Sources

4.2.2.1 The assessment area for noise impact assessment shall generally include all areas within 300m from the boundary of the Project and the works of the Project. The assessment area for airborne construction noise assessment and groundborne construction noise assessment are shown in Figure 4.2.1 and Figure 4.2.2 respectively. Table 4.6 shows the key existing noise sources for cumulative impact assessments and their locations are illustrated in Figure 4.2.3.

Table 4.6 – List of key existing noise sources

Types	Noise Sources	Reference Location
Existing Noise Sources	Chamber G	ENS01
	NTM WTW	ENS02

4.2.2.2 The existing noise sources are described as follows:

a) Chamber G

· For fixed noise source, the key existing fixed noise source is the ventilation fan which is located at the existing tunnel portal approximately 300m northeast from the closest NSRs in Ngau Tam Mei. Given the large separation distance and geographical separation and that the Project will not have any planned fixed noise sources as mentioned in Section 4.1.3, cumulative fixed noise sources impacts are not anticipated.

b) NTM WTW

· For fixed noise source, the key existing fixed noise sources are the ventilation louvres, plantroom exhaust, etc. within NTM WTW which are located at around 50m from the closest NSRs in Ngau Tam Mei. However, as discussed in Section 4.1.3, the Project will not have any planned fixed noise sources, cumulative fixed noise sources impacts are not anticipated.

c) NTM FWPSR

· For fixed noise source, there is no noticeable noise perceived at NTM FWPSR. Therefore, the NTM FWPSR is not included as existing fixed noise source. Nevertheless, as discussed in Section 4.1.3, the Project will not have any planned fixed noise sources, cumulative fixed noise sources impacts are not anticipated.

Planned Noise Sources

4.2.2.3 Other than the key existing noise sources, there are also planned noise sources from the Project and other concurrent projects which may give rise to potential noise impacts on existing and future NSRs. The list of projects is listed in Table 4.7 below and their locations are shown in Figure 4.2.3.

Table 4.7 – List of key planned noise sources

Types	Noise Sources	Reference Location
Possible Noise Sources from the Project	Fresh water trunk mains which encroach the boundary of CA	PNS01
	Modification of Chamber G within Lam Tsuen Country Park and CA	PNS02
Possible Noise Sources from other concurrent projects	NTM WTW Extension	PNS03
	NTM FWPSR Extension	PNS04
	Fresh water trunk mains which do not encroach the boundary of CA	PNS05
	Northern Link	PNS06
	Site Formation and Infrastructure Works for Public Housing Development at Sha Po, Shap Pat Heung and Tai Kei Leng, Yuen Long – Feasibility Study	PNS07

4.2.2.4 The possible noise sources from the Project are described as follows:

a) Fresh Water Trunk Mains which encroach the boundary of CA

· For airborne construction noise, the use of PME during the construction of fresh water trunk mains is expected to be the potential noise source. Therefore, airborne construction noise is considered in the assessment. For groundborne construction noise, as open-cut method will be used for the construction of fresh water trunk mains, groundborne construction noise is not anticipated.

· For fixed noise source, since the fresh water trunk mains will be laid underground and no water pumps will be installed at these sections, fixed noise source impacts are not anticipated.

b) Modification of Chamber G within Lam Tsuen Country Park and CA –

· For airborne construction noise, the modification works of Chamber G under EIA will be conducted underground only, airborne construction noise impacts are not anticipated. For groundborne construction noise, as the modification works of Chamber G are located at more than 300m from the nearest NSR, groundborne construction noise impacts are not anticipated.

· For fixed noise source, as mentioned in Section 4.1.3, there are no planned fixed noise sources located within Lam Tsuen Country Park and CA for the Project, i.e. within the scope of the EIA, potential fixed noise source impact is therefore not anticipated.

4.2.2.5 The possible noise sources from other concurrent projects are described as follows:

a) NTM WTW Extension

· For airborne construction noise, the extension works will involve minor excavation, construction of additional treatment facilities, modification works within existing facilities and modification works of Chamber G falling outside the boundary of CA, which will be carried out within the existing NTM WTW boundary. Cumulative airborne construction noise impact has been assessed in Appendix 4.4.7 and Appendix 4.4.8.

· For fixed noise source, the planned fixed noise source will include the ventilation exhaust/ louvre vents from additional facilities of NTM WTW and the ventilation building of Chamber G. However, as mentioned in Section 4.1.3, there are no planned fixed noise sources for the DP elements under this EIA. Therefore, cumulative fixed noise source impacts are not anticipated.

b) NTM FWPSR Extension

· For airborne construction noise, the extension works will involve minor excavation of the reserved reservoir extension area and the extension works will be carried out within the existing FWPSR site boundary. Cumulative airborne construction noise impact has been assessed in Appendix 4.4.7 and Appendix 4.4.8.

· For fixed noise source, since there are no planned fixed noise sources for NTM FWPSR and that there are no planned fixed noise sources for the DP elements under this EIA as mentioned in Section 4.1.3, cumulative fixed noise source impact is not anticipated.

c) Fresh Water Trunk Mains which do not encroach the boundary of CA

· For airborne construction noise, the works will involve laying of fresh water trunk mains from NTM WTW to the existing fresh water distribution system near Tan Kwai Tsuen and overlapping of works is expected. Cumulative airborne construction noise impact has been assessed in Appendix 4.4.7 and Appendix 4.4.8.

· For fixed noise source, since the fresh water trunk mains will be laid underground and no water pumps will be installed at these sections, fixed noise source is not anticipated. As mentioned in Section 4.1.3, there are no planned fixed noise sources for the DP elements under this EIA. Therefore, cumulative fixed noise source impacts are not anticipated.

d) Northern Link

· For airborne construction noise, the development of Mass Transit Railway Northern Link is near the fresh water trunk main laying works between Ching Yau Road and San Tam Road and may generate cumulative airborne construction noise. Cumulative airborne construction noise impact has been assessed in Appendix 4.4.7 and Appendix 4.4.8.

· For fixed noise source, planned fixed noise sources for Northern Link include the proposed Ngau Tam Mei station facilities and Long Ha Tsuen Ancillary Building near the fresh water trunk mains which encroach the boundary of the CA. As mentioned in Section 4.1.3, there are no planned fixed noise sources for the DP elements under this EIA. Therefore, cumulative fixed noise source impact is not anticipated.

e) Site Formation and Infrastructure Works for Public Housing Development at Sha Po, Shap Pat Heung and Tai Kei Leng, Yuen Long – Feasibility Study

· For airborne construction noise, potential airborne construction noise sources are expected during the construction phase of the project Site Formation and Infrastructure Works for Public Housing Development at Sha Po, Shap Pat Heung and Tai Kei Leng, Yuen Long – Feasibility Study. The construction works is anticipated to commence in Year 2026 and to be completed by Year 2031. The laying of fresh water trunk mains, involving excavation and backfilling in the vicinity of San Tam Road, is expected to be concurrent with the proposed road works of San Tam Road under the proposed public housing development at Sha Po. However, close liaison will be made with the corresponding parties of the concurrent project to avoid any overlapping works as far as practicable. Considering the small sections of construction area at each phase of the fresh water trunk main laying works and that close liaison will be made to coordinate the overlapping works, adverse cumulative environmental impacts with the Project are not anticipated.

· For fixed noise source, as mentioned in Section 4.1.3, there are no planned fixed noise sources for the DP elements under this EIA. Therefore, cumulative fixed noise source impacts are not anticipated.

4.3 Noise Sensitive Receivers

4.3.1.1 With reference to Annex 13 of the EIAO-TM, NSRs include all domestic premises, temporary housing accommodation, hostels, convalescent homes, homes for the aged, educational institutions (incl. kindergarten and nurseries), places of public worship, courts of law, hospitals, medical clinics, and any other premises or places that are considered by the Director to have similar sensitivity to noise as the above.

4.3.1.2 Representative NSRs within the assessment area have been identified and selected for assessment. These NSRs cover all existing sensitive developments, committed and planned NSRs during construction and operational phases of the Project.

4.3.1.3 The existing NSRs are identified by means of topographic maps, aerial photos, land status plans and site inspections. Planned / committed NSRs are identified by making reference to relevant OZP (OZP No. S/YL-NTM/13, S/YL-KTN/11, S/YL-MP/7, S/YL-NSW/9), S.16 / S.12a Town Planning Ordinance Development Permission Area Plans, Outline Development Plans (ODP), Layout Plans and other relevant published land use plans, including plans and drawings published by the Lands Department and any land use and development applications approved by Town Planning Board in the vicinity of the Project.

4.3.1.4 The representative NSRs in the vicinity, which may be affected are identified in Table 4.8 below. Appendix 4.3.1 shows the photos of existing representative NSRs.

Table 4.8 – Representative NSRs

No.^[1]	NSR	Uses^[2]	No. of Storey	Approx. distance from the Project (m)
NTM1	Ngau Tam Mei Village	R	1-3	~45
SW1	San Wai Village	R	1-3	~15
CY1	Village House near Ching Yau Road	R	1-2	~235
WP1	Village House near Wang Ping Shan South Road	R	2	~185
LH1	Long Ha Tsuen	R	1-2	~15
WO1	Wah On Villa	R	3	~250
ST1	Village House near San Tam Road	R	1	~240
Notes: [1] The assessment will only include NSRs which rely on opened windows for ventilation. [2] R – Residential Premises.

4.3.1.5 Representative NSRs locations that will be affected by airborne construction noise have been selected from Table 4.8 and are summarised in Table 4.9 below and the representative NAPs are shown in Figure 4.3.1.

Table 4.9 – Representative NSRs for airborne construction noise

No.^[1]	NSR	Uses^[2]	No. of Storey	Approx. distance from the Project (m)	NAP ^[3]
NTM1	Ngau Tam Mei Village	R	1-3	~45	NTM01 – NTM05
SW1	San Wai Village	R	1-3	~15	SW01, SW02
LH1	Long Ha Tsuen	R	1-2	~15	LH01
Notes: [1] The assessment will only include NSRs which rely on opened windows for ventilation. [2] R – Residential Premises. [3] NAP – Noise Assessment Point.

4.3.1.6 The closest existing representative NSRs at Ngau Tam Village are more than 300m away from the modification works of Chamber G. Given the large separation distance separation, adverse groundborne construction noise impacts from the modification of Chamber G are not anticipated.

4.3.1.7 As there are no planned fixed noise sources for the modification of Chamber G and the fresh water trunk mains, no representative NSRs will be affected by fixed noise source impacts. Hence, no adverse fixed noise source impact is anticipated.

4.4 Airborne Construction Noise Impact Assessment

4.4.1 Airborne Construction Noise Impact Assessment Methodology

4.4.1.1 The construction noise impact assessment during daytime, on weekdays other than general holidays has been assessed in accordance with the methodology in paragraphs 5.3 and 5.4 of Annex 13 of the TM.

4.4.1.2 Construction noise assessment will be conducted based on the following procedures:

a) Determine 300m from the boundary of the Project and the works of the Project;

b) Identify and locate representative NSRs that may be affected by the works;

c) Obtain the construction method and work sequence for the construction period;

d) Obtain the construction plant inventory for each corresponding construction work sequence;

e) Determine the Sound Power Levels (SWLs) of the plant items according to the information stated in the GW-TM or other recognised sources of reference, where appropriate;

f) Calculate the correction factors based on the distance between the NSRs and the notional noise source positions of the work sites;

g) Apply corrections for façade, distance, barrier attenuation, acoustic reflection where applicable;

h) Predict construction noise levels at the NSRs;

i) Quantify the level of impact at the NSRs, in accordance with Table 1B of Annex 5 of EIAO-TM and GW-TM;

j) Predict the cumulative noise impacts for any concurrent construction works in the vicinity of the proposed work;

k) For any exceedance of noise criteria, all practical mitigation measures such as alternative construction methodology, quiet plant, silencer, enclosure, etc, shall be examined to alleviate the predicted noise impacts as much as practicable; and

l) Consideration of noise mitigation measures will follow Annex 13 of EIAO-TM and EIAO Guidance Note “Preparation of Construction Noise Impact Assessment under the Environmental Impact Assessment Ordinance” [GN 9/2023].

4.4.2 Identification of Airborne Construction Noise Impact

Identification of Assessment Area and Noise Sensitive Receivers

4.4.2.1 For airborne construction noise, the assessment area includes area within 300m from the boundary of the Project and the works of the Project. Representative NSRs locations that will be affected by the construction activities are summarised in Table 4.9 and the representative NAPs are shown in Figure 4.3.1.

Inventory of Noise Sources

4.4.2.2 Key airborne construction activities involve site clearance, excavation, mainlaying and backfilling for construction of fresh water trunk mains.

4.4.2.3 These construction activities will be carried out with the use of PME including excavators, lorries, mobile cranes, concrete pumps, concrete mixers, etc. SWLs for each PME will be established according to GW-TM and other relevant information as appropriate. Appendix 4.4.1 presents the SWLs for each PME. If more than one PME is needed or when the stated equipment model is not available to the contractor at specific time periods, another PME/ QPME with the same or lower SWL will be adopted.

Utilization Rates and SWLs of Powered Mechanical Equipment

4.4.2.4 Practically, the PMEs will not be operating for all times within a work site. The utilization rates will depend on the construction sequences, work fronts scale and construction nature. In this assessment, the plant inventory and utilization rates have been confirmed to be practical for the purpose of this EIA by the Project’s Construction Professionals. Appendix 4.4.2 tabulates the adopted utilisation rates.

4.4.3 Evaluation of Airborne Construction Noise Impact

Phases of Construction

4.4.3.1 The construction activities involve site clearance, excavation, mainlaying and backfilling etc. It is anticipated that the Project will be implemented in phases. The construction programme with phases of construction has been given in Appendix 2.1.

Scenarios

4.4.3.2 Initially, airborne construction noise assessment has been carried out without any mitigation measures (i.e. the “Unmitigated Scenario”). If any noise level exceedance was identified, further assessments will be conducted assuming different combinations of mitigation measures to be incorporated (i.e. the “Mitigated Scenario”).

Prediction of Noise Impact

4.4.3.3 According to the latest engineering design, construction will mainly comprise of the activities as described in Section 4.4.2.2. The corresponding SWLs of these activities have been estimated according to the PME’s SWLs and guidelines in Annex 13 of EIAO-TM. Appendix 4.4.1 presents the SWLs for each PME. Appendix 4.4.2 gives the plant inventory adopted for each workfront and Appendix 4.4.3 shows the locations of workfronts adopted for this construction noise assessment.

4.4.3.4 Appendix 4.4.4 and Appendix 4.4.5 present the calculated unmitigated construction noise impacts at representative NSRs and at representative floor levels respectively. The predicted construction noise impacts at the NSRs under unmitigated scenario are summarised in Table 4.10 below.

Table 4.10 – Predicted construction noise impact at NSRs under unmitigated scenario

No.^[1]	NSR	NAP^[2]	Uses^[3]	Leq (30min), dB(A)
				Criterion	Unmitigated Noise Level ^[4]	Exceedance
Existing NSRs
NTM1	Ngau Tam Mei Village	NTM01	R	75	83	8
		NTM02	R	75	77	2
		NTM03	R	75	82	7
		NTM04	R	75	75	-
		NTM05	R	75	67	-
SW1	San Wai Village	SW01	R	75	84	9
		SW02	R	75	93	18
LH1	Long Ha Tsuen	LH01	R	75	94	19
Notes: [1] The assessment will only include NSRs which rely on opened windows for ventilation. [2] NAP- Noise Assessment Point. Only the first layer of NSRs has been selected for assessment. [3] R – Residential Premises. [4] Bolded values mean exceedance of the relevant noise criteria.

4.4.3.5 The total number of dwellings, classrooms and other noise sensitive receivers that will be exposed to noise impact exceeding the criteria set in Annex 5 in the EIAO-TM under unmitigated scenario have been calculated and are summarised in Table 4.11.

Table 4.11 – Number of residential dwellings/ rooms exceeding the noise criteria under unmitigated scenario

No. of Residential Dwellings	No. of Classrooms	No. of Other NSRs (Place of Public Worship, Accommodation / Hostel, Clinic / Home for the aged)	Total
55	0	0	55

4.4.4 Mitigation of Airborne Construction Noise Impact

4.4.4.1 The predicted noise levels show that the unmitigated construction noise impacts will exceed the daytime noise criteria. Mitigation measures are therefore required except for underground construction activities for the modification of Chamber G. The following mitigation measures have been considered:

· Use of Quieter Construction Methods and Equipment;

· Good site practices to limit noise emissions at the source;

· Use of quality powered mechanical equipment (QPME);

· Use of temporary noise barriers, noise enclosure, silencer and acoustic mat ; and

· Alternative use of plant items within one worksite, wherever practicable.

4.4.4.2 The above mitigation measures will need to be implemented in works sites as good practices where appropriate.

Use of Quieter Construction Methods and Equipment

4.4.4.3 To mitigate construction noise impacts, quieter construction equipment/ methods will be adopted, such as the use of hydraulic crusher for demolition, quieter type saw as an alternative for circular saw and silent press-in for sheet piling works. Moreover, the feasibility for the use of saw-and-lift method and self-compacting concrete, will be further reviewed in the detailed design and construction stages, and in the Construction Noise Management Plan (CNMP) (see Section 4.4.6).

Good Site Management Practices

4.4.4.4 Good site practice and noise management techniques could considerably reduce the noise impact from construction site activities on nearby NSRs. The following measures should be practised during each phase of construction:

· only well-maintained plant should be operated on-site and plant should be serviced regularly during the construction phase;

· machines and plant (such as trucks, cranes) that may be in intermittent use should be shut down between work periods or should be throttled down to a minimum;

· plant known to emit noise strongly in one direction, where possible, be orientated so that the noise is directed away from nearby NSRs;

· silencers or mufflers which available on construction equipment should be properly fitted and maintained during the construction works;

· mobile plant should be sited as far away from NSRs as possible and practicable;

· material stockpiles, site office and other structures should be effectively utilised, where practicable, to screen noise from on-site construction activities; and

· The benefits of these techniques can vary according to specific site conditions and operations. The environmental noise climate will certainly be improved with these control practices, although the improvement can only be quantified during implementation when specific site parameters are known.

4.4.4.5 The future Contractor shall strictly follow the Recommended Pollution Control Clauses for Construction Contracts and the recommendations in the CNMP to ensure compliance with the contract provisions as well as the environmental ordinances and their regulations. In addition, the relevant contract specifications recommended under ProPECC PN 1/24 shall also be adopted in the Construction Contract for the implementation of the recommended quieter construction methods and equipment.

Use of Quality Powered Mechanical Equipment (QPME)

4.4.4.6 The use of quiet plant associated with the construction works is made reference to the QPME/ other commonly used PME listed in EPD web pages as far as possible which includes the SWLs for specific PME and quiet PME.

Use of Movable Noise Barrier, Full Enclosure, Silencer and Acoustic Mat

4.4.4.7 Movable temporary noise barriers that can be located close to noisy plant and be moved concurrently with the plant along a worksite can be very effective for screening noise from NSRs. A typical design which has been used locally is a wooden framed barrier with a small-cantilevered upper portion of superficial density no less than 7kg/m² on a skid footing with 25mm thick internal sound absorptive lining. This measure is particularly effective for low level zone of NSRs. A cantilevered top cover will be required to achieve screening benefits at upper floors of NSRs.

4.4.4.8 Movable temporary noise barriers will be used for some PME (e.g. excavator). It is anticipated that suitably designed barriers could achieve at least 5dB(A) reduction for movable plant and 10dB(A) for stationary plant. Reference shall be made to the EPD’s website (https://www.epd.gov.hk/epd/misc/construction_noise/contents/index.php/en/demolition/item/157-construction-noise-barrier.html) as well as other internationally recognized standards for the design and configuration of the temporary noise barriers.

4.4.4.9 For the use of movable noise barrier for at-grade construction works, working space will be considered for their manoeuvrability and placement. Generally, sufficient separation between major plants during at-grade construction works is envisaged to cater for the use of temporary movable noise barriers onsite. Temporary movable noise barrier can be placed close to noise source locally as far as practicable.

4.4.4.10 The use of standard enclosure will be considered to shelter relatively fixed plant such as concrete pump. These standard enclosures can provide at least 15dB(A) noise reduction. Reference shall be made to the EPD’s website (https://www.epd.gov.hk/epd/misc/construction_noise/contents/index.php/en/demolition/item/158-construction-noise-enclosure.html) and GN9/2023 as well as other internationally recognized standards for the design and configuration of the standard enclosure.

4.4.4.11 Besides, the use of silencer will be considered for PME such as ventilation fan. The silencer can provide at least 15dB(A) noise reduction.

4.4.4.12 In addition, noise insulating fabrics (acoustic mats) with density no less than 7kg/m² will be installed for PME such as rock drill and the fabric should be lapped such that there will be no opening or gaps on the joints. With reference to the approved EIA for Northern Link (AEIAR-259/2024), Sai O Trunk Sewer Sewage Pumping Station (AEIAR-230/2021), North East New Territories New Development Areas (AEIAR-175/2013) and Alternative Ground Decontamination Works at the Proposed Kennedy Town Comprehensive Development Area Site (AEIAR-188/2015), these acoustic mats could achieve at least 10 dB(A) noise reduction. Therefore, a noise reduction of 10dB(A) for the PME lapped with the acoustic mats was assumed in this assessment.

4.4.4.13 A summary of the noise mitigation measures adopted for various PMEs is given in Appendix 4.4.1 and indicative drawings for barrier, enclosure and acoustic mat are shown in Appendix 4.4.6, and the associated noise reduction is summarised in Table 4.12.

Table 4.12 – Summary of noise mitigation measures adopted for PMEs

PME	Mitigation Measure	Attenuation, dB(A)
Air Compressor, air flow > 10m^3/min and ≤30m^3/min	Barrier	-5
Air Compressor, air flow > 30m^3/min	Barrier	-5
Asphalt Paver	Barrier	-5
Bar Bender and Cutter	Barrier	-5
Hand Held Breaker	Barrier	-5
Breaker, excavator mounted (pneumatic)	Barrier	-5
Breaker, excavator mounted (hydraulic)	Barrier	-5
Concrete Corer	Barrier	-5
Concrete Lorry Mixer	Barrier	-5
Concrete Pump	Enclosure	-15
Mobile Crane	Barrier	-5
Compactor, vibratory	Barrier	-5
Drill, percussive, hand-held (electric)	Barrier	-5
Grinder	Barrier	-5
Dump Truck	Barrier	-5
Dump Truck, with grab	Barrier	-5
Drill Rig	Barrier	-5
Excavator	Barrier	-5
Grout Mixer	Barrier	-10
Grout Pump	Barrier	-10
Hoist, passenger / material (electric)	Barrier	-5
Hoist, passenger/material (Petrol)	Barrier	-5
Lorry	Barrier	-5
Lorry, with crane/grab	Barrier	-5
Piling, Large Dia Bored, Reverse Circulation Drill	Barrier	-5
Power Rammer (Petrol)	Barrier	-10
Vibratory Poker	Barrier	-10
Vibrating Hammer	Barrier	-10
Poker	Barrier	-5
Rock Drill, crawler mounted (pneumatic)	Acoustic Mat	-10
Rock Drill, hand-held (pneumatic)	Barrier	-5
Road Roller	Barrier	-5
Roller, Vibratory	Barrier	-5
Saw, circular, wood	Barrier	-10
Saw, chain, hand-held	Barrier	-10
Saw, concrete	Barrier	-10
Ventilation Fan	Silencer	-15
Water Pump	Barrier	-5
Water Pump, submersible	Barrier	-5
Air Blower (electric)	Barrier	-5

4.4.4.14 In addition to the above-listed noise mitigation measures, retractable noise barrier will be erected along the workfront at San Wai Village and Long Ha Tsuen in front of the NSRs to further mitigate the construction noise. It is anticipated that these retractable noise barriers can provide about 10dB(A) noise reduction for the PME used at the worksites. Other than following the design and configuration for the temporary noise barriers given in Section 4.4.4.8, consideration will also be given to further extend the height and width of the retractable noise barriers in order to ensure that a 10 dB(A) noise reduction will be achieved for all the PMEs used at the worksite. Detail information on these PME is shown in Appendix 4.4.1.

4.4.4.15 The feasibility, practicability, programming and effectiveness of the above mitigation measures have been reviewed and confirmed by the Project’s construction professionals.

Alternative use of plant items within one worksite, wherever practicable

4.4.4.16 In practice, some plant items will operate sequentially within the same work site, and certain reduction of the predicted noise impacts could be achieved. However, any additional control on the sequencing of plant will impose a restrictive constraint to the Contractor on the operation and planning of plant items, and the implementation of the requirement will be difficult to be monitored. Hence, sequencing operation of PME has not been taken into consideration.

4.4.4.17 With the adoption of the above mitigation measures, the construction noise impacts from different phases of construction during the construction period have been calculated in accordance with the work programme and are given in Appendix 2.1.

4.4.4.18 Appendix 4.4.7 and Appendix 4.4.8 present the calculated construction noise impacts at representative NSRs and at representative floor levels respectively. The predicted construction noise impacts at the NSRs are summarised in the Table 4.13.

Table 4.13 – Predicted construction noise impact at NSRs under mitigated scenario

No.^[1]	NSR	NAP^[2]	Uses^[3]	Leq (30min), dB(A)
				Criterion	Mitigated Noise Level	Cumulative Noise Level	Exceedance
Existing NSRs
NTM1	Ngau Tam Mei Village	NTM01	R	75	65	70	-
		NTM02	R	75	59	68	-
		NTM03	R	75	64	64	-
		NTM04	R	75	57	64	-
		NTM05	R	75	49	65	-
SW1	San Wai Village	SW01	R	75	65	67	-
		SW02	R	75	74	74	-
LH1	Long Ha Tsuen	LH01	R	75	74	75	-
Notes: [1] The assessment will only include NSRs which rely on opened windows for ventilation. [2] NAP- Noise Assessment Point. Only the first layer of NSRs has been selected for assessment. [3] R – Residential Premises.

4.4.4.19 Cumulative impacts from concurrent projects were considered. The details of these concurrent projects are provided in Section 2.10. The plant inventory and mitigation measures for NTM WTW Extension, NTM FWPSR Extension, Fresh Water Trunk Mains under PER have been obtained from the relevant Project Proponent, and the SWLs for construction activities of Northern Link have been extracted from the approved EIA for Northern Link (AEIAR-259/2024) and adopted for cumulative airborne construction noise assessment. The details are presented in Appendix 4.4.2 and Appendix 4.4.7.

4.4.4.20 From Table 4.13, construction noise impacts at all NSRs including residential premises can be properly mitigated by implementing the proposed noise control measures.

4.4.4.21 The number of dwellings, classrooms and other sensitive receivers that will be exposed to noise impact exceeding the criteria set in Annex 5 in the TM is nil.

4.4.5 Evaluation of Residual Construction Noise Impact

4.4.5.1 Construction noise impact arising from the Project at all NSRs can be properly mitigated by implementing the proposed noise control measures. The number of dwellings, classrooms and other sensitive receivers that will be exposed to adverse residual construction noise impact exceeding the criteria set in Annex 5 in the TM is nil.

4.4.6 Construction Noise Impact Monitoring and Audit

4.4.6.1 The future Contractor will be required to prepare a CNMP with reference to Section 8 and Annex 21 of the EIAO-TM, EIAO Guidance Note No. 9/2023 on “Preparation of Construction Noise Impact Assessment under the Environmental Impact Assessment Ordinance”, as well as this EIA Report and EM&A Manual. The CNMP shall identify the inventory of noise sources, assess the effectiveness of the mitigation measures to be implemented for the Project quantitatively, review the effectiveness and practicality of all proposed mitigation measures for the construction noise impact of the Project and recommend the EM&A requirements if necessary.

4.5 Groundborne Construction Noise Impact Assessment

4.5.1.1 As discussed in Section 4.3, the closest existing representative NSRs at Ngau Tam Mei Village are located at more than 300m away from the modification works of Chamber G. Due to the large separation distance, no adverse groundborne construction noise impact from modification of Chamber G is anticipated.

4.6 Fixed Noise Sources Impact Assessment

4.6.1.1 As discussed in Section 4.3, there are no planned fixed noise sources for the modification of Chamber G and the fresh water trunk mains. Hence, no adverse fixed noise sources impact is anticipated. As mentioned in Section 4.1.3, the ventilation building of Chamber G will fall outside the boundary of CA and therefore will be addressed in a separate PER.

4.7 Conclusion

4.7.1.1 This Section presents the noise impact assessment for the Project. Representative NSR and assessment methodology to be adopted are outlined. Potential concurrent projects and sources during construction and operational phases have also been identified.

4.7.1.2 The assessment methodology presented is in line with the requirement stipulated in the EIA Study Brief and the EIAO-TM. The assessment findings and recommendations for airborne construction noise, groundborne construction noise and fixed noise sources impact assessment is summarised below.

Airborne Construction Noise

4.7.1.3 Noise arising from the construction activities of the Project will have unavoidable potential impact on the NSRs located in the vicinity of the works areas. Unmitigated construction noise levels at the representative NSRs are predicted, which are found to be within the range of 67 to 94dB(A).

4.7.1.4 Mitigation measures are recommended to reduce the noise levels to within the EIAO-TM noise criterion, including good site practices, quieter construction methods and equipment, movable noise barrier, noise enclosure, acoustic mat and retractable noise barrier. With the recommended mitigation measures in place, noise levels at all NSRs including residential premises could comply with the EIAO-TM daytime construction noise criterion.

4.7.1.5 In addition, the future contractor shall prepare a CNMP to identify the inventory of noise sources, review and assess the effectiveness of the mitigation measures to be implemented for the Project quantitatively and recommend the EM&A requirements if necessary.

Groundborne Construction Noise

4.7.1.6 The closest existing representative NSRs at Ngau Tam Village are located at more than 300m away from the modification works of Chamber G. Given the large separation distance, adverse groundborne construction noise impacts from the modification of Chamber G are not anticipated.

Fixed Noise Sources Impact

4.7.1.7 As discussed in Section 4.3, there are no planned fixed noise sources for the modification of Chamber G and the fresh water trunk mains. Hence, no adverse fixed noise sources impact is anticipated. As mentioned in Section 4.1.3, the ventilation building of Chamber G will fall outside the boundary of CA and therefore will be addressed in a separate PER.

5 Water Quality Impact

5.1 Legislation, Standards, Guidelines and Criteria

5.1.1 General

5.1.1.1 The relevant legislation, standards, and guidelines applicable to the present Study for the assessment of water quality impacts include:

· Environmental Impact Assessment Ordinance (EIAO) (Cap. 499);

· Water Pollution Control Ordinance (WPCO) (Cap. 358);

· Technical Memorandum on Standards for Effluents Discharged into Drainage and Sewerage Systems, Inland and Coastal Waters (DSS-TM);

· ProPECC PN 2/23 “Construction Site Drainage”;

· ProPECC PN 1/23 “Drainage Plans subject to Comment by the Environmental Protection Department”;

· Hong Kong Planning Standards and Guidelines (HKPSG); and

· Environment, Transport and Works Bureau (ETWB) Technical Circular (Works) No. 5/2005: Protection of Natural Streams/Rivers from Adverse Impacts Arising from Construction Works.

5.1.2 Environmental Impact Assessment Ordinance (EIAO) (Cap. 499)

5.1.2.1 EIAO (Cap. 499) provides the major statutory framework for the environmental impact assessment in Hong Kong. Under Section 16 of the EIAO, EPD issued the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM) which specifies the assessment methods and criteria for the EIA. Annexes 6 and 14 of the EIAO-TM stipulate the “Criteria for Evaluating Water Pollution” and “Guidelines for Assessment of Water Pollution” respectively.

5.1.3 Water Pollution Control Ordinance (Cap. 358)

5.1.3.1 WPCO (Cap. 358) provides the major statutory framework for the protection and control of water quality in Hong Kong. According to the Ordinance and its subsidiary legislation, the entire Hong Kong waters are divided into ten Water Control Zones (WCZs) and four supplementary WCZs. Each WCZ has a designated set of statutory Water Quality Objectives (WQOs). The WQOs set limits for different parameters that should be achieved in order to protect specific beneficial uses and conservation goals of each of the zones.

5.1.3.2 The assessment area is situated within the Deep Bay WCZ and the water quality objectives for the Deep Bay WCZ are summarised in Table 5.1.

Table 5.1 – WQOs of Deep Bay WCZ

Water Quality Objectives	Part or Parts of Zone
Aesthetic Appearance
- Waste discharges shall cause no objectionable odours or discolouration of the water. - Tarry residues, floating wood, articles made of glass, plastic, rubber of any other substances should be absent. - Mineral oil should not be visible on the surface. Surfactants should not give rise to a lasting foam. - There should be no recognisable sewage-derived debris. - Floating, submerged and semi-submerged objects of a size likely to interfere with the free movements of vessels, or cause damage to vessels, should be absent. - Waste discharges shall not cause the water to contain substances which settle to form objectionable deposits.	- Whole Zone
Bacteria
- The level of Escherichia coli should not exceed 610 per 100mL, calculated as the geometric mean of all samples collected in a calendar year.	- Secondary Contact Recreation Subzone and Mariculture Subzone
- The level of Escherichia coli should not exceed 180 per 100 mL, calculated as the geometric mean of all samples collected from March to October inclusive. Samples should be taken at least 3 times in one calendar month at intervals of between 3 and 14 days.	- Yung Long Bathing Beach Subzone
- The level of Escherichia coli should be zero per 100 mL, calculated as the running median of the most recent 5 consecutive samples taken at intervals of between 7 and 21 days.	- Yuen Long & Kam Tin (Upper) Subzone, Beas Subzone, Indus Subzone, Ganges Subzone and Water Gathering Ground Subzones
- The level of Escherichia coli should not exceed 1 000 per 100mL, calculated as the running median of the most recent 5 consecutive samples taken at intervals of between 7 and 21 days.	- Yuen Long & Kam Tin (Lower) Subzone and Other Inland Waters
Colour
- Waste discharge shall not cause the colour of water to exceed 30 Hazen units.	- Yuen Long & Kam Tin (Upper) Subzone, Beas Subzone, Indus Subzone, Ganges Subzone, and Water Gathering Ground Subzones
- Waste discharges shall not cause the colour of water to exceed 50 Hazen units.	- Yuen Long & Kam Tin (lower) Subzone and other inland waters
Dissolved Oxygen
- Waste discharges shall not cause the level of dissolved oxygen to fall below 4 milligrams per litre for 90% of the sampling occasions during the year; values should be taken at 1 metre below surface.	- Inner Marine Subzone excepting Mariculture Subzone
- Waste discharges shall not cause the level of dissolved oxygen to fall below 4 milligrams per litre for 90% of the sampling occasions during the year; values should be calculated as water column average (arithmetic mean of at least 2 measurements at 1 metre below the surface, mid-depth, and 1 metre above seabed). In addition, the concentration of dissolved oxygen should not be less than 2 milligrams per litre within the 2 metres of the seabed for 90% of the sampling occasions during the year.	- Outer Marine Subzone excepting Mariculture Subzone
- The dissolved oxygen level should not be less than 5 milligrams per litre for 90% of the sampling occasions during the year; values should be taken at 1 meter below surface.	- Mariculture Subzone
- Waste discharges shall not cause the level of dissolved oxygen to be less than 4 milligrams per litre.	- Yuen Long & Kam Tin (Upper and Lower) Subzones, Beas Subzone, Ganges Subzone, Water Gathering Ground Subzones and other inland waters of the Zone
pH
- The pH of the water should be within the range of 6.5 – 8.5 units. In addition, the waste discharges shall not cause the natural pH range to be extended by more than 0.2 units.	- Marine waters excepting Yung Long Bathing Beach Subzone
- Waste discharges shall not cause the pH of the water to exceed the range of 6.5 – 8.5 units.	- Yuen Long & Kam Tin (Upper and Lower) Subzones, Beas Subzone, Ganges Subzone, Water Gathering Ground Subzones
- The pH of the water should be within the range of 6.0 – 9.0 units.	- Other inland waters
- The pH of the water should be within the range of 6.0 – 9.0 units for 95% of the samples. In addition, waste discharges shall not cause the natural pH range to be extended by more then 0.5 units.	- Yung Long Bathing Beach Subzone
Temperature
- Waste discharges shall not cause the natural daily temperature range to change by more than 2.0°C.	- Whole Zone
Salinity
- Waste Discharges shall not cause the natural ambient salinity to change by more than 10%.	- Whole Zone
Suspended Solids (SS)
- Waste discharges shall neither cause the natural ambient level to be raised by more than 30% nor give rise to accumulation of SS which may adversely affect aquatic communities.	- Marine waters
- Waste discharges shall not cause the annual median of SS to exceed 20 milligrams per litre.	- Yuen Long & Kam Tin (Upper and Lower) Subzones, Beas Subzone, Ganges Subzone, Water Gathering Ground Subzones and other inland waters
Ammonia
- The un-ionised ammoniacal nitrogen level should not be more than 0.021 mg/l calculated as the annual average (arithmetic mean).	- Whole Zone
Nutrients
- Nutrients shall not be present in quantities sufficient to cause excessive or nuisance growth of algae or other aquatic plants	- Inner and Outer Marine Subzones
- Without limiting the generality of objective above, the level of inorganic nitrogen should not exceed 0.7 milligram per litre, expressed as annual mean.	- Inner Marine Subzone
- Without limiting the generality of objective above, the level of inorganic nitrogen should not exceed 0.5 milligram per litre, expressed as annual water column average (arithmetic mean of at least 2 measurements at 1 metre below surface and 1 metre above seabed).	- Outer Marine Subzone
5-Day Biochemical Oxygen Demand
- Waste discharges shall not cause the 5-day biochemical oxygen demand to exceed 3 milligrams per litre	- Yuen Long & Kam Tin (Upper) Subzone, Beas Subzone, Indus Subzone, Ganges Subzone, and Water Gathering Ground Subzones
- Waste discharges shall not cause the 5-day biochemical oxygen demand to exceed 5 milligrams per litre	- Yuen Long & Kam Tin (Lower) Subzone, and other inland waters
Chemical Oxygen Demand
- Water discharges shall not cause the chemical oxygen demand to exceed 15 milligrams per litre	- Yuen Long & Kam Tin (Upper) Subzone, Beas Subzone, Indus Subzone, Ganges Subzone, and Water Gathering Ground Subzones
- Water discharges shall not cause the chemical oxygen demand to exceed 30 milligrams per litre	- Yuen Long & Kam Tin (Lower) Subzone, and other inland waters
Toxins
- Waste discharges shall not cause the toxins in water to attain such a level as to produce significant toxic, carcinogenic, mutagenic or teratogenic effects in humans, fish or other aquatic organisms, with due regard to biologically cumulative effects in food chains and to interactions of toxic substances with each other; and - Waste discharges shall not cause a risk to any beneficial use of the aquatic environment.	- Whole Zone
Phenol
- Phenols shall not be present in such quantities as to produce a specific odour, or in concentrations than 0.05 milligrams per litre as C6H5OH	- Yung Long Bathing Beach Subzone
Turbidity
- Waste discharges shall not reduce light transmission substantially from the normal level.	- Yung Long Bathing Beach Subzone

5.1.4 Technical Memorandum on Standards for Effluents Discharged into Drainage and Sewerage Systems, Inland and Coastal Waters (DSS-TM)

5.1.4.1 Under Section 21 of the WPCO (Cap. 358), Technical Memorandum for Effluents Discharged into Drainage and Sewerage Systems, Inland and Coastal Waters was issued to control the physical, chemical and microbial quality of effluent discharges into foul sewers, stormwater drains, inland and coastal waters. Specific limits apply for different areas are different between surface waters and sewers. The limits vary with the rate of effluent flow. Any sewage from the development should comply with the standards for effluent discharged into foul sewers, as stipulated in the DSS-TM. Specific limits apply for different area and beneficial use of the water bodies. Hence, the limits vary with the rate of effluent flow. Standard for effluents discharged into the inland waters for Group A (inland water abstracted mainly for portable water supply), Group B, and Group C usages are summarised in Table 5.2, Table 5.3 and Table 5.4 respectively.

Table 5.2 – Standards for effluents discharged into Group A Inland Waters

Flow rate (m^3/day)	≤10	>10 & ≤100	>100 & ≤500	>500 & ≤1000	>1000 & ≤2000
pH (pH units)	6.5 – 8.5	6.5 – 8.5	6.5 – 8.5	6.5 – 8.5	6.5 – 8.5
Temperature (°C)	35	35	30	30	30
Colour (lovibond units) (25mm cell length)	1	1	1	1	1
Conductivity (µs/cm at 20°C	1000	1000	1000	1000	1000
SS	10	10	5	5	5
Dissolved Oxygen	≥4	≥4	≥4	≥4	≥4
BOD	10	10	5	5	5
COD	50	50	20	20	20
Oil & Grease	1	1	1	1	1
Boron	2	2	1	0.5	0.5
Barium	2	2	1	0.5	0.5
Iron	2	2	1	0.5	0.5
Arsenic	0.05	0.05	0.05	0.05	0.05
Total chromium	0.05	0.05	0.05	0.05	0.05
Mercury	0.001	0.001	0.001	0.001	0.001
Cadmium	0.001	0.001	0.001	0.001	0.001
Selenium	0.01	0.01	0.01	0.01	0.01
Copper	0.2	0.2	0.2	0.2	0.1
Lead	0.1	0.1	0.1	0.1	0.1
Manganese	0.5	0.5	0.5	0.5	0.5
Zinc	1	1	1	1	1
Other toxic metals individually	0.1	0.1	0.1	0.1	0.1
Total toxic metals	0.3	0.3	0.2	0.2	0.15
Cyanide	0.05	0.05	0.05	0.05	0.02
Phenols	0.1	0.1	0.1	0.1	0.1
Hydrogen Sulphide	0.05	0.05	0.05	0.05	0.05
Sulphide	0.2	0.2	0.1	0.1	0.1
Fluoride	1	1	1	1	0.5
Sulphate	800	600	500	400	200
Chloride	800	500	500	200	200
Total reactive phosphorous	1	0.7	0.7	0.5	0.5
Ammonia nitrogen	1	1	1	1	0.5
Nitrate + nitrite nitrogen	15	15	15	10	10
E.coli (count/100ml)	<1	<1	<1	<1	<1
Note: All units in mg/L unless otherwise stated; all figures are upper limits unless otherwise indicated.

Table 5.3 – Standards for effluents discharged into Group B Inland Waters

Flow rate (m^3/day)	≤200	>200 & ≤400	>400 & ≤600	>600 & ≤800	>800 & ≤1000	>1000 & ≤1500	>1500 & ≤2000	>2000 & ≤3000
pH (pH units)	6.5 – 8.5	6.5 – 8.5	6.5 – 8.5	6.5 – 8.5	6.5 – 8.5	6.5 – 8.5	6.5 – 8.5	6.5 – 8.5
Temperature (°C)	35	30	30	30	30	30	30	30
Colour (lovibond units) (25mm cell length)	1	1	1	1	1	1	1	1
SS	30	30	30	30	30	30	30	30
BOD	20	20	20	20	20	20	20	20
COD	80	80	80	80	80	80	80	80
Oil & Grease	10	10	10	10	10	10	10	10
Iron	10	8	7	5	4	3	2	1
Boron	5	4	3	2.5	2	1.5	1	0.5
Barium	5	4	3	2.5	2	1.5	1	0.5
Mercury	0.001	0.001	0.001	0.001	0.001	0.001	0.001	0.001
Cadmium	0.001	0.001	0.001	0.001	0.001	0.001	0.001	0.001
Selenium	0.2	0.2	0.2	0.2	0.2	0.1	0.1	0.1
Other toxic metals individually	0.5	0.5	0.2	0.2	0.2	0.1	0.1	0.1
Total toxic metals	2	1.5	1	0.5	0.5	0.2	0.2	0.2
Cyanide	0.1	0.1	0.1	0.08	0.08	0.05	0.05	0.03
Phenols	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1
Sulphide	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
Fluoride	10	10	8	8	8	5	5	3
Sulphate	800	800	600	600	600	400	400	400
Chloride	1000	1000	800	800	800	600	600	400
Total phosphorous	10	10	10	8	8	8	5	5
Ammonia nitrogen	5	5	5	5	5	5	5	5
Nitrate + nitrite nitrogen	30	30	30	20	20	20	10	10
Surfactants (total)	5	5	5	5	5	5	5	5
E.coli (count /100ml)	100	100	100	100	100	100	100	100
Note: All units in mg/L unless otherwise stated; all figures are upper limits unless otherwise indicated.

Table 5.4 – Standards for effluents discharged into Group C Inland Waters

Flow rate (m^3/day)	≤100	>100 and ≤500	>500 and ≤1000	>1000 and ≤2000
pH (pH units)	6-9	6-9	6-9	6-9
Temperature (℃)	30	30	30	30
Colour (lovibond units) (25mm cell length)	1	1	1	1
SS	20	10	10	5
BOD	20	15	10	5
COD	80	60	40	20
Oil & Grease	1	1	1	1
Boron	10	5	4	2
Barium	1	1	1	0.5
Iron	0.5	0.4	0.3	0.2
Mercury	0.001	0.001	0.001	0.001
Cadmium	0.001	0.001	0.001	0.001
Silver	0.1	0.1	0.1	0.1
Copper	0.1	0.1	0.05	0.05
Selenium	0.1	0.1	0.05	0.05
Lead	0.2	0.2	0.2	0.1
Nickel	0.2	0.2	0.2	0.1
Other toxic metals individually	0.5	0.4	0.3	0.2
Total toxic metals	0.5	0.4	0.3	0.2
Cyanide	0.05	0.05	0.05	0.01
Phenols	0.1	0.1	0.1	0.1
Sulphide	0.2	0.2	0.2	0.1
Fluoride	10	7	5	4
Sulphate	800	600	400	200
Chloride	1000	1000	1000	1000
Total phosphorus	10	10	8	8
Ammonia nitrogen	2	2	2	1
Nitrate + nitrite nitrogen	30	30	20	20
Surfactants (total)	2	2	2	1
E. coli (count/100ml)	1000	1000	1000	1000
Note: All units in mg/L unless otherwise stated; all figures are upper limits unless otherwise indicated.

5.1.5 ProPECC PN 2/23 “Construction Site Drainage”

5.1.5.1 Professional Persons Environmental Consultative Committee Practice Notes (ProPECC PN 2/23) on Construction Site Drainage provides guidelines for the handling and disposal of construction discharges. This note is applicable for the control of site runoff and wastewater generated during the construction phase of the Project.

5.1.5.2 The types of discharges from construction sites outlined in the ProPECC PN 2/23 include:

· Surface runoff;

· Groundwater;

· Boring and drilling water;

· Wastewater from concrete batching and precast concrete casting;

· Wheel washing water;

· Bentonite slurry;

· Water for testing and sterilisation of water retaining structures and water pipes,

· Wastewater from building construction,

· Acid cleaning, etching, and pickling wastewater, and

· Wastewater from site facilities.

5.1.6 ProPECC PN 1/23 “Drainage Plans subject to Comment by the Environmental Protection Department”

5.1.6.1 ProPECC PN 1/23 issued by EPD in 2023 provides guidelines on the environmental design and pollution control in drainaged plans submitted under Building (standards of Sanitary Fitments, Plumbing, Drainage Work and Latrines) Regulations 40(1), 40(2), 41(1), and 90. Any submitted drainage plans submitted shall be referred to EPD for comment on whether there may be concerns regarding pollution control.

5.1.7 Hong Kong Planning Standards and Guidelines

5.1.7.1 Chapter 9 of the HKPSG outlines the environmental requirements that needs to be considered during land use planning. The recommended guidelines and standards highlight a framework for planning against water pollution and provides guidelines for potentially polluting uses. It also lists out environmental factors that influences land use planning and recommends buffer distances for land uses.

5.1.8 ETWB TC (W) No. 5/2005: Protection of Natural Streams/Rivers from Adverse Impacts Arising from Construction Works

5.1.8.1 The ETWB TC (W) No. 5/2005 provides a framework to better protect all natural streams/rivers from the adverse impacts of construction works. The procedures promulgated under the Circular aims to clarify and strengthen existing measures for protection of natural streams/rivers from both government and private projects/developments. The guidelines and precautionary mitigation measures given in the ETWB TC (W) No. 5/2005 should be followed to the best of abilities to protect inland watercourses at or near the Project area during the construction phase.

5.2 Baseline Conditions

5.2.1 Inland River

5.2.1.1 Fairview Park Nullah is a major watercourse identified at the vicinity of the assessment area, which flows into the Deep Bay ultimately. The monitoring station of the Nullah (FVR1) recorded a WQO compliance rate of 69% in 2022, compared to 47% in 2002, its WQI was “Fair” in 2022. Water quality data reported in the Annual River Water Quality Report (2022) are presented in Table 5.5. The location is shown in Figure 5.1.

Table 5.5 – Summary of EPD’s routine river water quality data for Fairview Park Nullah in 2022

Parameter ^[3]	Fairview Park Nullah ^[1][2][4][5]
	FVR1
Dissolved oxygen (mg/L)	6.4
	(3.3 - 10.4)
pH	7.4
	(6.9 - 8.6)
SS (mg/L)	19.0
	(1.2 - 83.0)
5-day Biochemical Oxygen Demand (mg/L)	10.0
	(5.5 - 16.0)
Chemical Oxygen Demand (mg/L)	29
	(23 - 66)
Oil & grease (mg/L)	<0.5
	(<0.5 - 0.7)
Faecal coliforms (cfu/100mL)	120,000
	(17,000 - 1,400,000)
E. coli (cfu/100mL)	51,000
	(5,900 – 1,100,000)
Ammonia-nitrogen (mg/L)	1.100
	(0.320 - 2.900)
Nitrate-nitrogen (mg/L)	0.470
	(0.095 - 1.500)
Total Kjeldahl nitrogen (mg/L)	3.00
	(2.00 - 4.50)
Orthophosphate phosphorous (mg/L)	0.260
	(0.130 - 0.470)
Total phosphorus (mg/L)	0.55
	(0.35 - 0.71)
Sulphide (mg/L)	<0.02
	(<0.02 - 0.04)
Aluminium (µg/L)	<50
	(<50 - <50)
Cadmium (µg/L)	<0.1
	(<0.1 - <0.1)
Chromium (µg/L)	<1
	(<1 - 1)
Copper (µg/L)	2
	(<1 - 2)
Lead (µg/L)	<1
	(<1 - <1)
Zinc (µg/L)	11
	(<10 - 20)
Flow (L/s)	NM

Notes:

[1] Data presented are annual median of monthly samples; except those for faecal coliforms and E. coli which are in annual geometric means.

[2] Figures in brackets are annual ranges.

[3] NM indicates indicates no measurement taken.

[4] Values at or below laboratory reporting limits are presented as laboratory reporting limits.

[5] Equal values for annual medians (or geometric means) and ranges indicate that all data are the same as or below laboratory reporting limits.

5.3 Representative Water Sensitive Receivers

5.3.1.1 The assessment area for the water quality impact assessment shall include areas within 500 m from the boundary of the Project, which covers the Deep Bay Water Control Zone as designated under the Water Pollution Control Ordinance (Cap. 358). The Water Sensitive Receiver (WSRs) within 500m assessment area including watercourses, areas of ecological sensitivity and conservation importance, are shown in Figure 5.1, Figure 5.1a, and Figure 5.1b; and listed under Table 5.6 below:

Table 5.6 Representative Water Sensitive Receivers

ID	WSR	Horizontal Distance to Project Boundary, m
W1	Lam Tsuen Country Park	Overlaps Project boundary
W2	Conservation Areas	Overlaps Project boundary
W3	Active Fishponds	~90
W4	Abandoned Fishpond	~430
W5	Natural Watercourses near NTM WTW	Adjacent to Project boundary
W6	Modified Watercourses near NTM WTW	Adjacent to Project boundary
W7	Natural and modified Watercourses near Long Ha	Adjacent to Project boundary
W8	Modified Watercourses near Long Ha	Adjacent to Project boundary

5.4 Identification and Evaluation of Environmental Impacts – Construction Phase

5.4.1 General

5.4.1.1 The Project involves the laying of about 1km of freshwater mains which encroach into boundary of CA between NTM WTW and NTM FWPSR, and Ching Yau Road and San Tam Road, and the modification of Chamber G near NTM WTW as discussed in Section 2.7. Hence, the potential water pollution sources are mainly induced from the Project’s construction works are identified below:

· Construction runoff and general construction activities;

· Sewage due to construction workforce;

· Construction works in close proximity of inland water;

· Sterilisation of water mains prior to its commission;

· Accidental spillage of chemicals; and

· Tunnelling and underground works.

5.4.2 Construction Runoff and General Construction Activities

5.4.2.1 Construction site runoff are generated from work sites, and has the potential to cause adverse water quality impacts. The potential pollution sources from construction site runoffs may include:

· Runoff and erosion from site surfaces, earth working areas and stockpiles;

· Accidental release of any bentonite slurries, concrete washing and other grouting materials with construction runoff, stormwater or groundwater dewatering process;

· Wash water from concrete washing, dust suppression sprays and wheel washing facilities; and

· Chemicals spillage such as fuel, oil, solvents and lubricants from the maintenance of construction machinery and equipment.

5.4.2.2 In addition, during rainstorm events, site runoff would wash away soil particles on unpaved lands and areas with exposed topsoil. The runoff is generally considered to have high concentrations of SS. Discharge of uncontrolled site runoff would increase the SS levels and turbidity in the nearby water environment. Site runoff may also wash away contaminated soil particles and therefore cause adverse water quality impacts.

5.4.2.3 Various types of construction activities that would generate wastewater including pipe laying, general site cleaning and polishing, vehicle wheel and equipment washing, dust suppression and equipment installation. These construction site activities may have the potential to cause water pollution as they typically contain a high concentration of SS. Uncontrolled effluent could lead to deterioration in water quality for nearby WSRs, however its impacts could be minimised with good construction site practices.

5.4.3 Sewage due to Construction Workforce

5.4.3.1 Sewage will arise from the sanitary facilities (i.e. portable toilets) provided for the on-site construction workforce. Sewage is characterised by high levels of BOD5, Ammonia and E. coli counts. According to Table T-2 of Guidelines for Estimating Sewage Flows for Sewage Infrastructure Planning (GESF), the unit flow factor (UFF) is 0.23m³/day/employee (0.08 m³/day/employee for commercial employee and 0.15m³/day/employee for employees of construction activities). There will be a workforce of around 160 people, hence a total sewage of about 37m³/day will be generated. Adequate portable chemical toilets should be provided to avoid direct discharge into any nearby watercourse or public drains, no adverse water quality impacts are anticipated.

5.4.4 Construction Works in Close Proximity of Inland Water

5.4.4.1 As discussed in Section 2, sections of the proposed alignment of the fresh water trunk mains would cross watercourses located near Lam Tsuen Country Park. Open cut construction method would be adopted for the pipe works. The existing upstream watercourses that cross access roads were already modified as concrete drainage transfer pipes. Hence based on the latest design, no modification nor flow diversion works are required, therefore, no adverse water quality impacts on the watercourses/rivers, which intersect with the alignment of the proposed fresh water trunk mains, are anticipated.

5.4.4.2 Moreover, construction activities in close proximity of the inland watercourses may pollute the inland water bodies due to the potential release of construction wastes. Construction wastes are generally characterised by high concentration of SS and elevated pH. With the implementation of adequate construction site drainage as specified in the ProPECC PN 2/23 “Construction Site Drainage” and the provision of mitigation measures as described in the ETWB TC (Works) No. 5/2005 “Protection of natural streams / rivers from adverse impacts arising from construction works”, no adverse water quality impacts are anticipated.

5.4.5 Sterilisation of Water Mains Prior to its Commission

5.4.5.1 New fresh water trunk mains must be cleaned and sterilised before being its commission for public use. Typically, water mains are sterilised by chlorination. Subsequently, the treated effluent will be de-chlorinated to comply with WPCO requirements before discharge. The purpose of chlorination is to disinfect the water main, resulting in an absence of coliforms as confirmed by laboratory analysis before they are placed in service. In the case that discharge of sterilised water is required, the residual chlorine of sterilised water is hence identified as a potential source of adverse water quality impact. Since chlorination is involved, sterilisation effluent should be treated to an acceptable level in accordance with DSS-TM for storm drains before disposal.

5.4.6 Accidental Spillage of Chemicals

5.4.6.1 The use of chemicals such as engine oil and lubricants, and their storage as waste materials has the potential to create impacts on the water quality if spillage occurs and enters adjacent water environment. Waste oil may infiltrate into the surface soil layer, or runoff into the nearby water environment, increasing hydrocarbon levels. The potential impacts could however be mitigated by practical mitigation measures and good site practices.

5.4.7 Tunnelling and Underground Works

5.4.7.1 As discussed in Section 2, the modification works of Chamber G would involve underground excavation adopting mining and drill-and-break (D&B) methods, which may result in groundwater infiltration. Groundwater infiltration which may increase site runoff and lead to potential groundwater table drawdown. Any potential drawdown could result in different degrees of settlement and dewatering of surface waterbodies (i.e. nearby fishponds and watercourses), and hence groundwater in the vicinity may also be depleted. Suspended Solids would also be a key concern as infiltrated water could increase the amount of construction site runoff from the site to nearby drainage systems. Considerations should be taken to minimise the potential impacts from the change in groundwater level. Appropriate measures during any and all underground work would also be proposed to minimise the potential impact from groundwater drawdown.

5.5 Identification and Evaluation of Environmental Impacts – Operational Phase

5.5.1 General

5.5.1.1 The operation of the new fresh water trunk mains and Chamber G would not generate any new discharges to the surrounding water bodies. Nonetheless, the following is identified as a potential water pollution source associated with the operational phase of the Project:

· Stormwater runoff from paved or developed areas within the Project.

5.5.2 Stormwater runoff from paved or developed areas within the Projects

5.5.2.1 Surface runoff would be generated from the paved or developed areas within the Project which may contain debris, refuse, and dust. However given the nature of the Project, the proposed works would only result in marginal increase in stormwater runoff under the Project. Hence, no adverse water quality impact from stormwater runoff is expected.

5.6 Cumulative Impacts from Concurrent Project

5.6.1.1 The construction of the Project potentially overlaps with the construction period of other nearby concurrent projects as identified in Section 2.10, which includes Site Formation and Infrastructure Works for Public Housing Developments at Sha Po, Shap Pat Heung and Tai Kei Leng, Yuen Long, Northern Link, and NTM WTW Extension. However, with incorporation of the recommended mitigation measures during the construction and operational phases of the Project, the water quality impact generated from the Project would be localised and no adverse cumulative water quality impacts would be expected.

5.7 Mitigation Measures Recommendations – Construction Phase

5.7.1 Construction Runoff and General Construction Activities

5.7.1.1 Best Management Practices (BMPs) of mitigation measures in controlling water pollution and good site management, as specified in Practice Note for Professional Persons on Construction Site drainage, EPD, 2023 (ProPECC PN 2/23) should be followed as applicable to minimise potential water quality impacts during construction phase.

5.7.1.2 All effluent discharged from the construction site should comply with the standards stipulated in the DSS-TM. The following mitigation measures according to ProPECC PN 2/23 should be implemented as necessary so as to minimise potential water quality impacts, which includes but are not limited to:

a) All exposed earth areas should be completed and vegetated as necessary and as soon as possible after earthworks have been completed. If excavation of soil cannot be avoided during the rainy season, or at any time of year when rainstorms are likely, exposed slope surfaces should be covered by tarpaulin or other means. Deposited silt and grit should be removed regularly and disposed of by spreading evenly over stable, vegetated areas. Considering that pipe laying works would be carried out by open-cut method, it is not practicable to avoid excavations works in the wet season as this would affect the overall construction programme. However, for works area that is close to watercourses, excavation works shall avoid the rainy season as far as possible. Excavation works shall be proceeded section by section.

b) All open stockpiles of construction materials (for example, aggregates, sand and fill material) should be covered with tarpaulin or similar fabric during rainstorms. Measures should be taken to prevent the washing away of construction materials, soil, silt or debris into any drainage system.

c) Manholes at the vicinity of works area should always be adequately covered and temporarily sealed so as to prevent silt, construction materials or debris being washed into the drainage system and storm runoff being directed into foul sewers.

d) Precautions should be taken at any time of year when rainstorms are likely, actions to be taken when a rainstorm is imminent or forecasted, and actions to be taken during or after rainstorms are summarised in Appendix A2 of ProPECC PN 2/23. Particular attention should be paid to the control of silty surface runoff during storm events.

e) Construction solid waste, debris and rubbish on site should be collected, handled and disposed of properly to avoid water quality impacts.

f) Water used in water testing to check leakage of structures and pipes should be reused for other purposes as far as practicable. Surplus unpolluted water could be discharged into storm drains.

g) Earthworks final surfaces should be well compacted and the subsequent permanent work or surface protection should be carried out immediately after the final surfaces are formed to prevent erosion caused by rainstorms. Appropriate drainage like intercepting channels should be provided where necessary.

h) Groundwater pumped out of wells, etc. for the lowering of ground water level in basement or foundation construction, and groundwater seepage pumped out of tunnels or caverns under construction should be discharged into storm drains after the removal of silt in silt removal facilities where necessary.

i) Water used in ground boring and drilling for site investigation or rock/soil anchoring should as far as practicable be recirculated after sedimentation. When there is a need for final disposal, the wastewater should be discharged into storm drains via silt removal facilities where necessary.

j) In the case that bentonite is used for construction, it should be reconditioned and reused wherever practicable to minimise the disposal volume of used bentonite slurries. Temporary enclosed storage locations should be provided on-site for any unused bentonite that needs to be transported away after the related construction activities are completed.

5.7.1.3 Good site practices should be adopted to remove rubbish and litter from construction sites so as to prevent the rubbish and litter from spreading from the site area. It is recommended to clean the construction sites on a regular basis.

5.7.1.4 Requirements to be incorporated in the Project contract document should be established based on the water quality mitigation measures as mentioned above.

5.7.2 Sewage from Construction Workforce

5.7.2.1 No discharge of sewage to the stormwater system and marine water will be allowed. Adequate and sufficient portable chemical toilets should be provided in the works areas, to handle sewage from the construction workforce. Should there be any on-site kitchens or canteens, a temporary storage tank should be provided to collect wastewater. A registered collector should be employed to clean and maintain the chemical toilets on a regular basis.

5.7.2.2 Notices should be posted at conspicuous locations to remind the workers not to discharge any sewage or wastewater into the surrounding environment. Regular environmental audit of the construction site should be conducted to provide an effective control of any malpractices and achieve continual improvement of environmental performance on site.

5.7.3 Construction Works in Close Proximity of Inland Water

5.7.3.1 Watercourses near Lam Tsuen Country Park are identified in close proximity of the proposed construction works. As the existing upstream watercourses that crosses access roads were already modified as concrete drainage transfer pipes, no adverse water quality impact is anticipated from construction works, however as a conservative approach and to further limit potential water quality impacts of pipe laying using open cut method, open cut trench section shall be proceeded section by section. Moreover, the practices outlined in ETWB TC (Works) No. 5/2005 “Protection of natural streams/rivers from adverse impacts arising from construction works” should also be adopted where applicable to minimise the water quality impacts. Relevant mitigation measures from the ETWB TC (Works) No. 5/2005 are listed below:

· Construction works close to the inland waters should be carried out in dry season as far as practicable where the flow in the surface channel or stream is low.

· Trenches should be dug and backfilled in short sections. Measures should be taken to minimise the ingress of rainwater into trenches.

· The use of less or smaller construction plants may be specified in areas close to the water courses to reduce the disturbance to the surface water.

· Temporary storage of materials (e.g. equipment, chemicals and fuel) and temporary stockpile of construction materials should be located well away from any watercourses during carrying out of the construction works.

· Stockpiling of construction materials and dusty materials should be covered and located away from any watercourses. Construction debris and spoil should be covered up and / or disposed of as soon as possible to avoid being washed into the nearby water receivers.

· Proper shoring may need to be erected in order to prevent soil or mud from slipping into the watercourses.

5.7.4 Sterilisation of Water Mains Prior to its Commission

5.7.4.1 A WPCO discharge license for discharge of effluent from the construction site shall be applied for the construction phase. Effluent from the sterilised water mains should be dechlorinated to ensure total residual chlorine concentrations have complied with the standards stipulated under the WPCO discharge license before discharge. The cleaning and flushing water would also be treated and desilted to ensure compliance with the requirements of the WPCO discharge license. Adequate temporary storage tanks with sufficient capacity or contacting time for dechlorination should be provided to allow proper treatment of the effluent prior to discharge.

5.7.4.2 Specific advice from EPD should be sought during the design stage of the works with regards to the disposal of the sterilising water. Details of the chlorination and dechlorination treatment process, treatment facilities, treatment capacity, discharge volume, chemicals for dechlorination, implementation programme, sampling location(s), discharge location(s), monitoring frequency should be submitted to EPD.

5.7.4.3 The total residual chlorine should be measured in-situ at the discharge point(s) to ensure the residual chlorine has complied with the requirements stipulated under the WPCO discharge license when dechlorinated water is being discharged. If the dechlorinated water exceeds the allowed concentration, discharge must be suspended and the water should be circulated to a standby tank for further dechlorination and testing until the water quality comply with the discharge requirements.

5.7.5 Accidental Chemical Spillage

5.7.5.1 Contractor must register as a chemical waste producer if chemical wastes would be produced from the construction activities. The Waste Disposal Ordinance (Cap 354) and its subsidiary regulations in particular the Waste Disposal (Chemical Waste) (General) Regulation, should be observed and complied with for control of chemical wastes. The Contractor is also recommended to develop management procedures for chemicals used and prepare an emergency spillage handling procedure to deal with chemical spillage in case of an accident occurs.

5.7.5.2 Any services and maintenance facilities should be located on hard standings within a bunded area, and sumps and oil interceptors should be provided. Maintenance of vehicles and equipment involving activities with the potential for leakage and spillage should only be undertaken within the areas appropriately equipped to control these discharges. The service and maintenance as well as any chemical storage area would be avoided to position near the watercourse as a safeguard.

5.7.5.3 Disposal of chemical wastes should be carried out in compliance with the Waste Disposal Ordinance. The Code of Practice on the Packaging, Labelling, and Storage of Chemical Wastes published under the Waste Disposal Ordinance details the requirements to deal with chemical wastes. General requirements are given as follows:

· Suitable containers should be used to hold the chemical wastes to avoid leakage or spillage during storage, handling, and transport.

· Chemical waste containers should be suitably labelled, to notify and warn the personnel who are handling the wastes, to avoid accidents.

· Storage area should be selected at a safe location on-site and adequate space should be allocated to the storage area.

5.7.5.4 The Contractor should devise a contingency plan for any accidental spillage and heavy rainfall event.

5.7.6 Tunnelling and Underground Works

5.7.6.1 To minimise the groundwater infiltration, the following groundwater control strategies and mitigation measures are recommended:

· The Contractor should undertake rigorous probing of the ground ahead of tunnelling/excavation works to identify zones of potential significant water inflow. In zones where significant water inflow could occur due to discrete, permeable features, grouting should be applied to reduce overall inflow of groundwater;

· Where water inflow quantities are excessive, pre-grouting will be required to reduce the water inflow into the tunnel;

· In case there is still excessive drawdown of the groundwater table, even after the implementation of the water control strategies, post-grouting should be applied as far as practicable; and

· Waterproof lining will be installed after the formation of the tunnel and cavern;

· Regular groundwater table should be monitored during the tunnelling works. All the available limited groundwater monitoring points will initially be located at the portal until additional groundwater monitoring points are proposed at other locations during the detailed design stage; and

· In the event of seepage of groundwater occurs, groundwater should be collected inside the works areas before discharging to the existing stormwater drainage system via silt removal facilities. The discharges during construction phase shall comply with WPCO requirements.

5.7.6.2 With the proper implementation of the groundwater control strategies and mitigation measures, groundwater infiltration is unlikely, hence, no adverse water quality impacts are expected.

5.8 Mitigation Measures Recommendations – Operational Phase

5.8.1 Stormwater Runoff from Paved or Developed Areas within the Project

5.8.1.1 As discussed in Section 5.5.2, considering that the proposed works would only result in marginal increase in stormwater runoff during the operational phase of the project, no adverse water quality impacts are expected. Hence, no mitigation measures are required.

5.9 Residual Impacts

5.9.1.1 With the full implementation of the recommended mitigation measures for the construction phase of the proposed Project, no unacceptable residual impacts on water quality are anticipated. It is recommended that regular audit of the implementation of the recommended mitigation measures be carried out during the construction phase.

5.10 Environmental Monitoring and Audit (EM&A)

5.10.1.1 With the implementation of the recommended mitigation measures and ensuring all site effluents are properly treated before discharge, no adverse water quality impact is envisaged during the construction phase of the Project. It is recommended that regular site inspections during the construction phase should be undertaken to inspect the construction activities and works areas to ensure the recommended mitigation measures are properly implemented. Regular groundwater table should be monitored during the modification works of Chamber G. Precise location of the groundwater monitoring wells is subject to the geo-survey before the construction works. Details of the audit requirements are provided in the stand-alone EM&A Manual for the Project.

5.10.1.2 As no adverse water quality impact is anticipated, no EM&A activities is required during operational phase.

5.11 Conclusion

5.11.1.1 The key water quality impact associated with the laying of fresh water trunk mains and the modification of Chamber G could impact the water bodies through general construction activities, construction site runoff, sterilisation of water mains prior to commissioning, accidental spillage of chemicals, sewage effluent from construction workforce, and tunnelling and underground works. With proper implementation of the recommended mitigation measures, no adverse water quality impacts would be anticipated during construction phase.

5.11.1.2 During operation phase of the Project, stormwater runoff is identified as a potential source of water pollution. However, no adverse water quality impacts would be anticipated.

6 Waste Management Implications

6.1 Legislation, Standards and Guidelines

6.1.1 General

6.1.1.1 The relevant legislation, standards and guidelines applicable to the study for the assessment of waste management implications include:

· Criteria and guidelines for evaluating and assessing waste management implications as specified in Annexes 7 and 15 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM);

· Waste Disposal Ordinance (WDO) (Cap. 354) and subsidiary Regulations;

· Waste Disposal (Chemical Waste) (General) Regulation (Cap. 354C);

· Waste Disposal (Charges for Disposal of Construction Waste) Regulation (Cap. 354N).

· Land (Miscellaneous Provisions) Ordinance (Cap. 28); and

· Public Health and Municipal Services Ordinance (Cap. 132) – Public Cleansing and Prevention of Nuisances Regulation;

6.1.2 Criteria and Guidelines for Evaluating and Assessing Waste Management Implications as specified in Annexes 7 and 15 of the EIAO-TM

6.1.2.1 Annex 7 of the EIAO-TM describes the criteria for assessing waste management implication which include provision of adequate waste handling, storage, collection, transfer, treatment and disposal facilities during both construction and operational phases, provision of adequate facilities to facilitate waste reduction, exploration of beneficial use of waste generated as well as alternatives which generate minimal amount of waste.

6.1.2.2 Annex 15 of the EIAO-TM describes the approaches and methodologies for assessment of waste management implications arising from the project.

6.1.3 Waste Disposal Ordinance

6.1.3.1 The WDO prohibits any unauthorised disposal of wastes. Construction waste, defined under Cap. 354N of the WDO, refers to a substance, matter or thing which is generated from construction works. It includes all abandoned materials, whether processed or stockpiled or not, before being abandoned, but does not include sludge, screenings or matter removed or generated from desludging, desilting or dredging works.

6.1.3.2 Under the WDO, wastes can only be disposed of at designated waste disposal facilities licensed by Environmental Protection Department (EPD). Breach of this Ordinance can lead to a fine and/ or imprisonment. The WDO also stipulates the requirements for issuing licenses for the collection and transportation of wastes.

6.1.4 Waste Disposal (Chemical Waste) (General) Regulation

6.1.4.1 Issued under the WDO, the Waste Disposal (Chemical Waste) (General) Regulation controls the possession, provides regulations for chemical waste control, and administers the possession, storage, collection, transport and disposal of chemical wastes. EPD has also issued a “guideline” document, the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes (1992), which details how the Contractor should comply with the regulations on chemical wastes.

6.1.5 Waste Disposal (Charges for Disposal of Construction Waste) Regulation

6.1.5.1 Under the Waste Disposal (Charges for Disposal of Construction Waste) Regulation, construction waste delivered to a landfill for disposal must not contain more than 50% by weight of inert material. Construction waste delivered to a sorting facility for disposal must contain more than 50% by weight of inert material, and construction waste delivered to a Public Fill Reception Facility for disposal must consist entirely of inert material.

6.1.6 Land (Miscellaneous Provisions) Ordinance

6.1.6.1 The inert portion of Construction and Demolition (C&D) materials may be taken to Public Fill Reception Facilities (PFRFs) operated by the Civil Engineering and Development Department (CEDD). The Ordinance requires Dumping Licenses (to be issued by CEDD) to be obtained by individuals or companies, who deliver inert C&D materials to the public filling facilities.

6.1.6.2 Individual licenses and windscreen stickers are issued for each vehicle involved. Public filling areas will accept only inert building debris, soil, rock and broken concrete. The material should, however, be free from marine mud, household refuse, plastic, metal, individual and chemical wastes, animal and vegetable matters and any other materials considered unsuitable by the Filling Supervisor.

6.1.7 Public Cleansing and Prevention of Nuisances Regulation

6.1.7.1 The regulation provides control on illegal dumping of wastes on unauthorised (unlicensed) sites.

6.1.8 Other Relevant Guidelines

6.1.8.1 The following documents and guidelines in Table 6.1 are also related to waste management and disposal:

Table 6.1 – Other relevant documents and information

Bureau / Department	Documents / Guidelines / Technical Circulars
Development Bureau (DEVB)	- WBTC No. 2/93, Public Dumps - WBTC No 2/93B, Public Filling Facilities - WBTC No. 16/96, Wet Soil in Public Dumps - WBTC Nos. 4/98 and 4/98A, Use of Public Fill in Reclamation and Earth Filling Project - WBTC No. 19/2001, Metallic Site Hoardings and Signboards - WBTC No. 12/2002, Specification Facilitating the Use of Recycled Aggregates - DEVB TCW No. 06/2010, Trip Ticket System for Disposal of Construction & Demolition Materials. - DEVB TCW No. 08/2010, Enhanced Specification for Site Cleanliness and Tidiness - DEVB TCW No. 09/2011, Enhanced Control Measures for Management of Public Fill - ETWB TCW No. 19/2005, Environmental Management on Construction Sites
CEDD	- Project Administration Handbook for Civil Engineering Works (2022 Edition) - CEDD TC No. 11/2019, Management of Construction and Demolition Materials
Environment and Ecology Bureau	- A Guide to the Chemical Waste Control Scheme - A Guide to the Registration of Chemical Waste Producers - Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes - Monitoring of Solid Waste in Hong Kong 2022
Buildings Department	- ADV-19, Practice Note for Authorized Persons and Registered Structural Engineers on Construction and Demolition Waste

6.2 Description of the Environment

6.2.1 Existing Environment

6.2.1.1 The modification works of Chamber G are located within a rural area in Ngau Tam Mei, while a section of the proposed fresh water trunk mains runs from Ngau Tam Mei Water Treatment Works (NTM WTW) towards the Ngau Tam Mei Fresh Water Primary Service Reservoir (NTM FWPSR) along an existing access road, which cuts through the Conservation Area (CA) and are aligned immediately adjacent to Lam Tsuen Country Park. Another section of the proposed fresh water trunk mains fall within a CA between Ching Yau Road and San Tam Road. The project layout is shown in Figure 1.1.

6.3 Construction Phase

6.3.1 Assessment Methodology

6.3.1.1 The assessment of waste management implications from handling, storage, collection, transportation, and disposal of solid waste materials generated by the landuse proposals has been undertaken in accordance with Annexes 7 and 15 of the EIAO-TM and the EIA Study Brief No. ESB-333/2020.

Waste Management Hierarchy

6.3.1.2 The waste management hierarchy has been applied in the assessment and development of mitigation measures for waste. The waste management hierarchy is a concept which shows the desirability of various waste management methods and comprises the following in descending order of preference:

· Avoidance;

· Minimisation;

· Recycling/reuse;

· Treatment; and

· Disposal.

Avoiding, Reducing, Reusing and Recycling Opportunities

6.3.1.3 All opportunities for avoiding, reducing, reusing and recycling of waste have been explored based upon the following factors:

· Avoiding or minimising waste generation throughout design, construction and operational phases;

· Adopting better management practices to promote segregation materials;

· Reuse and recycling on site or other projects; and

· Diverting any surplus inert C&D materials to public fills subject to site conditions.

6.3.1.4 For the proposed fresh water trunk main, various options were considered during design stage to minimise generation of C&D materials. Based on Section 2.5, the current option for the section between NTM WTW and NTM FWPSR is to adopt alignment along the access road/slope adjacent to existing access. Alternative option of adopting alignment along the boundary of CA was considered, it is 250m longer than current approach and open cut method with more tree clearance is required due to small bending radius and complicated pipe routing and terrain. The current option can hence minimise C&D materials generation. Similar consideration was taken for the section between Ching Yau Road and San Tam Road, the adopted option can minimise C&D materials generation with less tree-felling and excavation of natural terrain.

6.3.1.5 For modification of Chamber G, the proposed work would be conducted by both mined excavation with drill and break to avoid above-ground works within the CA. Drill and break instead of drill and blast method would be adopted to minimise overbreak and thus reduce generation of excavated material.

Analysis of Activities and Waste Generation

6.3.1.6 The quantity, quality and timing of the waste arising as a result of the construction activities of the Project and its associated works have been estimated, based on the sequence and duration of these activities.

6.3.1.7 The design, general layout, construction methods and programme to minimise the generation of inert C&D materials for the construction works have been considered.

6.3.1.8 The potential waste management implications associated with the handling, transportation and disposal of non-inert C&D materials arising from the construction works have been assessed with reference to the following approach:

· Estimation of the types, timing and quantities of the non-inert C&D materials to be generated; and

· Assessment of the potential waste management implications on the collection, transfer and disposal of non-inert C&D materials.

Proposal for Waste Management

6.3.1.9 Prior to considering the disposal options for various types of wastes, opportunities for reducing waste generation, on-site or off-site reuse and recycling have been evaluated. Measures which can be taken in the design phase (e.g. modifying the design approach) and in the construction phase for maximising waste reduction have been separately considered.

6.3.1.10 After considering the opportunities for reducing waste generation and maximising reuse, the types and quantities of the remaining wastes required to be disposed of have been estimated and the disposal options for each type of wastes have been described. The disposal method recommended for each type of wastes has taken into account the result of the assessment.

6.3.1.11 The impacts caused by handling (including labelling, packaging and storage), collection, and reuse/disposal of waste have been addressed and appropriate mitigation measures have been proposed.

6.3.2 Identification and Evaluation of Waste Management Implications

6.3.2.1 Different types of waste to be generated during the construction phase can be divided into the following distinct categories based on their source and compositions:

· C&D material;

- Inert C&D materials (such as rocks and soft materials etc.);

- Non-inert C&D materials (such as bamboo, timber, paper plastic etc.);

· Chemical waste from maintenance of mechanical equipment (such as cleaning fluids, solvents, waste lubricating oil and fuel etc.); and

· General refuse.

C&D Materials

6.3.2.2 The works for the Project would tentatively commence in Year 2025. Major construction activities which would generate C&D materials include:

a) Fresh water trunk mains between NTM WTW and NTM FWPSR:

- Site clearance;

- Excavation works; and

- Mainlaying.

b) Fresh water trunk mains between Ching Yau Road and San Tam Road:

- Site clearance;

- Excavation works; and

- Mainlaying.

c) Chamber G:

- Construction of water tunnels; and

- Mainlaying.

6.3.2.3 Summary of estimated amount of C&D materials to be generated during construction phase is shown in Table 6.2 below.

Table 6.2 – Estimated amount of C&D materials generated during construction phase

Construction Activities	Amount of C&D materials to be generated (m^3)
	Inert C&D Materials			Non-inert C&D Materials^[1]
	Inert soft C&D Materials^[2]	Rock^[3]	AHM^[4]
Fresh Water Trunk Mains between NTM WTW and NTM FWPSR ^[5]
Site clearance, excavation works and mainlaying	9,990	0	1,110	13,320
Fresh Water Trunk Mains between Ching Yau Road and San Tam Road ^[6]
Site clearance, excavation works and mainlaying	3,560	0	400	3,960
Chamber G ^[7]
Construction of access tunnels, bypass tunnels and chambers	60,460	172,170	0	0
Note: [1] “Non-inert C&D material” includes, but not limited to, bamboo, timber, paper and plastic, etc. [2] “Inert Soft C&D Material” includes, but not limited to excavated soil, etc. [3] “Rock” includes all grade rock. [4] “AHM” includes, but not limited to broken concrete and granular materials, etc. [5] Based on current construction method, the excavation extent within CA is estimated at 3m(W) x 740m(L) x 5m(D). [6] Based on current construction method, the excavation extent within CA is estimated at 3m(W) x 220m(L) x 6m(D). [7] Based on current construction method, soft tunnel cross section within CA&CP is 240m^2 with total length of 229m for inert soft C&D materials estimation, with 10% overbreak volume; For rock estimation, since the shapes of Chamber G2, G3, G4 are irregular, the amount of rock generated is based on model estimation with a 10% overbreak volume.

6.3.2.4 C&D materials contain a mixture of inert and non-inert materials and is mainly generated from various construction activities. The quantity of inert C&D materials and non-inert C&D materials to be produced from the construction are estimated to be approximately 247,690 m³ and 17,280 m³ respectively. Stockpiling area within the works area is proposed for temporary storage of C&D materials. Nevertheless, all inert C&D materials should first be considered to reuse as fill materials and the rest parts should be delivered to PFRFs as a last resort. In case the inert C&D materials excavated cannot meet the fill material requirements and reuse for some geotechnical works such as site formation, filling materials will be imported from public fill bank subject to agreement with fill management authority of CEDD. Meanwhile, all non-inert C&D materials should first be considered to recycle and be disposed of at the landfill as a last resort. Mitigation measures for C&D materials are detailed in Section 6.3.3. As the Project generates more than 50,000 m³ C&D materials, a Construction and Demolition Material Management Plan (C&DMMP) will be submitted separately during EIA stage to the Public Fill Committee (PFC) for approval.

Chemical Waste

6.3.2.5 Materials classified as chemical waste are listed in the Waste Disposal (Chemical Waste) (General) Regulation. The main chemical waste types arising from the construction of the Project may include the following:

· Scrap batteries;

· Spent hydraulic oils and waste fuel;

· Spent lubrication oils and cleaning fluids from mechanical machinery; and

· Spent solvent from equipment cleaning activities.

6.3.2.6 Chemical waste may pose the following environmental, health and safety hazards if not stored and disposed of appropriately:

· Toxic effects to workers;

· Adverse effects on water and land from spills; and

· Fire hazards.

6.3.2.7 It is difficult to quantify the amount of chemical waste as it will be highly dependent on the Contractor’s on-site maintenance practice and the quantities of plant and vehicles utilised. Nevertheless, it is anticipated that the quantity of chemical waste, such as lubrication oil and solvent produced from plant maintenance, will be in the order of few hundred litres per month.

6.3.2.8 The estimated amount of chemical waste to be generated during construction phase is summarised in Table 6.3.

Table 6.3 – Summary of estimated amount of chemical waste to be generated during construction phase

Chemical Waste	Estimated Amount of Chemical Waste to be Generated
Scrap Batteries	few hundred kilograms or less per month
Spent Hydraulic Oil and Waste Fuel	few hundred litres or less per month
Spent Lubrication Oil and Cleaning Fluids
Spent Solvent

6.3.2.9 Storage, handling, transport and disposal of chemical waste should be arranged in accordance with the Code of Practice on the Packaging, Labelling and Storage of Chemical Waste published by the EPD. Chemical waste should be collected by a licensed chemical waste collector and to be disposed of at a licensed chemical waste treatment and disposal facility. Opportunities for the reuse and recycling of materials will be taken subject to site conditions. Mitigation measures for chemical wastes are detailed in Section 6.3.3. Provided that the handling, storage and disposal of chemical wastes are in accordance with these requirements, adverse environmental impacts are not expected.

General Refuse

6.3.2.10 The construction workers would generate refuse comprising of food waste, waste paper, aluminium cans and plastic bottles during the construction period.

6.3.2.11 The storage of general refuse may give rise to adverse environmental impacts. These could include water quality, odour and visual impact in the form of windblown litter. The construction site may also attract pests and vermin if the storage areas are not well maintained and cleaned regularly. In addition, disposal of waste at sites other than the approved disposal facilities could also lead to similar adverse impacts at those sites.

6.3.2.12 The exact number of work force (clerical and workers) to be employed for the Project is not available at this stage, but is anticipated to be about 160 staff. Based on the generation rate of 0.65kg/person/day, the total refuse generated per day would be about 104kg/day at peak time for works areas. It is estimated that approximately 170 tons of general refuse would be generated during construction phase. Summary of estimated amount of general refuse to be generated during construction phase is summarised in Table 6.4.

Table 6.4 – Summary of general refuse generated during the construction phase

Size of Work Force	Waste Generation Rate (kg/person/day)	Daily Waste Generation (kg/day)	Duration (months) ^[1]	Total Amount Generated (tonne)
160	0.65	104	63	170
Notes: [1] Assume 26 working days per month.

6.3.2.13 Mitigation measures for general refuse are detailed in Section 6.3.3. Provided that the mitigation measures are adopted, the potential environmental impacts caused by the storage, handling, transportation and disposal of general refuse are expected to be minimal, and adverse environmental impacts caused by the storage, handling, transportation and disposal of general refuse are not expected.

Transportation Arrangement for Waste Disposal

6.3.2.14 Land transportation would be used to deliver and dispose of the waste generated to the designated disposal outlets. The tentative transportation routings during the construction phase are shown in Table 6.5. Maximum number of trips anticipated during construction stage is approximately 64 trips per day. No barging points and associated conveyor systems will be established and used for the Project. The transportation routings may be changed subject to the actual traffic conditions of the roads. Nevertheless, no adverse environmental impact is anticipated due to the transportation of waste with the implementation of appropriate mitigation measures (e.g. using water-tight containers and dump trucks equipped with mechanical cover).

Table 6.5 – Tentative transportation routings and frequency of trucks involved for waste delivery and disposal during construction phase

Outlet	Type of Waste	Tentative Transportation Routing
Tuen Mun (TM) Area 38 / Tseung Kwan O (TKO) Area 137 Fill Bank ^[1]	Inert C&D Material	Ngau Tam Mei >Ching Yau Road >Chuk Yau Road >San Tam Road >San Tin Highway >Yuen Long Highway >Tuen Mun Road >Wong Chu Road > Lung Fu Road >Lung Mun Road >TM Area 38 Fill Bank or Ngau Tam Mei > New Territories Circular Road > Tsing Long Highway > Tsing Kwai Highway > Ching Cheung Road > Lung Cheung Road > Kwun Tong Road > Tseung Kwan O Road > Wan Po Road > TKO Area 137 Fill Bank
West New Territories (WENT) Landfill	Non-inert C&D Material and General Refuse	Ngau Tam Mei > Ching Yau Road >Chuk Yau Road >San Tam Road >San Tin Highway >Yuen Long Highway >Tuen Mun Road >Wong Chu Road >Lung Fu Road >Lung Mun Road >Lung Kwu Tan Road >Nim Wan Road >WENT Landfill
Chemical Waste Treatment Centre (CWTC)	Chemical Waste	Ngau Tam Mei > Ching Yau Road >Chuk Yau Road >San Tam Road >San Tin Highway >Tsing Long Highway >Ching Hong Road >Tsing Yi Road >CWTC

Note:

[1] The disposal site of inert C&D materials is subject to the designation by the Public Fill Committee according to DEVB TC(W) No.6/2010.

Summary of Construction Waste

6.3.2.15 A summary of construction waste arising from the Project with total quantities of each type of construction waste to be generated, reused and delivered/disposed of as well as recommendation for outlets during the construction programme is presented in Table 6.6. The total quantities of each type of waste to be generated, reused and delivered/disposed of during the construction phase is presented in Table 6.7.

Table 6.6 – Summary of total quantities for each type of waste to be generated and proposed outlets during construction programme

Year	Waste type	Total Amount Generated (m^3)	Total Amount Reused (m^3)^[1]		Total Amount Disposed (m^3)	Recommended Outlets
			On-site	Off-site
Fresh Water Trunk Mains NTM WTW and NTM FWPSR
2026	Inert C&D materials ^[2] [3]	3,820	1,020	0	2,800	On-site & off-site reuse ^[5] / backfilling prior to delivery to TM Area 38 / TKO Area 137 Fill Bank for beneficial reuse in other projects / off-site reuse at other possible outlets
	Non-inert C&D materials	5,000	0	0	5,000	Recycle subject to site conditions (e.g. recycle timber and woody materials at Y-Park) prior to disposal to WENT Landfill as last resort
2027	Inert C&D materials ^[2] [3]	5,570	1,510	0	4,060	On-site & off-site reuse ^[5] / backfilling prior to delivery to TM Area 38 / TKO Area 137 Fill Bank for beneficial reuse in other projects / off-site reuse at other possible outlets
	Non-inert C&D materials	5,500	0	0	5,500	Recycle subject to site conditions (e.g. recycle timber and woody materials at Y-Park) prior to disposal to WENT Landfill as last resort
2028	Inert C&D materials ^[2] [3]	1,710	460	0	1,250	On-site & off-site reuse ^[5] / backfilling prior to delivery to TM Area 38 / TKO Area 137 Fill Bank for beneficial reuse in other projects / off-site reuse at other possible outlets
	Non-inert C&D materials	2,820	0	0	2,820	Recycle subject to site conditions (e.g. recycle timber and woody materials at Y-Park) prior to disposal to WENT Landfill as last resort
Fresh Water Trunk Mains between Ching Yau Road and San Tam Road
2025	Inert C&D materials ^[2] [3]	3,960	1,070	0	2,890	On-site reuse / backfilling prior to delivery to TM Area 38 / TKO Area 137 Fill Bank for beneficial reuse in other projects / off-site reuse at other possible outlets
	Non-inert C&D materials	3,960	0	0	3,960	Recycle subject to site conditions (e.g. recycle timber and woody materials at Y-Park) prior to disposal to WENT Landfill as last resort
Chamber G
2026	Inert C&D materials ^[2] [3]	46,900	13,140	3,080	30,680	Off-site reuse ^[5] / backfilling prior to delivery to TM Area 38 / TKO Area 137 Fill Bank for beneficial reuse in other projects / off-site reuse at other possible outlets
	Non-inert C&D materials	0	0	0	0	N.A.
2027	Inert C&D materials ^[2] [3]	40,700	4,990	24,070	11,640	Off-site reuse ^[5] / backfilling prior to delivery to TM Area 38 / TKO Area 137 Fill Bank for beneficial reuse in other projects / off-site reuse at other possible outlets
	Non-inert C&D materials	0	0	0	0	N.A.
`2028	Inert C&D materials ^[2] [3]	50,590	0	50,590	0	Off-site reuse / backfilling prior to delivery to TM Area 38 / TKO Area 137 Fill Bank for beneficial reuse in other projects / off-site reuse at other possible outlets
	Non-inert C&D materials	0	0	0	0	N.A.
2029	Inert C&D materials ^[2] [3]	62,290	0	62,290	0	Off-site reuse / backfilling prior to delivery to TM Area 38 / TKO Area 137 Fill Bank for beneficial reuse in other projects / off-site reuse at other possible outlets
	Non-inert C&D materials	0	0	0	0	N.A.
2030	Inert C&D materials ^[2] [3]	32,150	0	32,150	0	Off-site reuse / backfilling prior to delivery to TM Area 38 / TKO Area 137 Fill Bank for beneficial reuse in other projects / off-site reuse at other possible outlets
	Non-inert C&D materials	0	0	0	0	N.A.
Other Waste during Construction
2025-2030	Chemical Waste^[4]	few hundred litres/kg or less per month	Recycle subject to site conditions			Recycle subject to site conditions prior to collection by a licensed collector to be disposed of at the CWTC
	General Refuse	170 tonnes	Recycle subject to site conditions			Recycle onsite subject to site conditions prior to disposal to WENT Landfill
Notes: [1] Assume approximately 30% inert soft C&D materials from mainlaying works to be reused on-site and 100% rock to be re-used off-site, subject to results from laboratory test on rock. Upon commencement of the works, other Works Departments will be actively coordinated to see if the surplus C&D materials from the Site can be utilised for appropriate purposes in other project(s). [2] Disposal site of inert C&D materials is subject to the designation by the Public Fill Committee according to DEVB TC(W) No.6/2010. [3] “Inert C&D Material” includes Rocks, AHM and Inert soft C&D Material. [4] “Chemical Waste” measured by volume (litres) includes spent hydraulic oil & waste fuel, spent lubrication oil & cleaning fluids, and spent solvent. Scrap batteries are measured by weight (kg). [5] For off-site reuse of inert C&D materials, concrete waste in artificial hard materials will be sorted out from other wastes and recycled at recycling plant to form aggregates for road sub-base. The aggregates from artificial hard material and inert soft material will be beneficially reused by exporting to other concurrent projects. Besides, granite in the excavated rock resulted from construction activities will be delivered to quarry site for further processing as aggregate, if available, subject to result of mortar bar test.

Table 6.7 – Total quantities of each type of waste to be generated, reused & disposed of during construction phase

Waste Type	Total Amount Generated, m^3	Total Amount Reused, m^3		Total Amount Disposed, m^3	Recommended Outlets
		On-site	Off-site
Inert C&D Materials ^[1]	247,690	22,190	172,180	53,320	Reused on-site / delivery to TM Area 38 / TKO Area 137 Fill Bank for beneficial reuse in other projects/ off-site reuse at other possible outlets
Non-inert C&D Materials	17,280	0	0	17,280	Recycle subject to site conditions (e.g. recycle timber and woody materials at Y-Park) prior to disposal to WENT Landfill as last resort
Chemical Waste	Few hundred litres/kg or less per month	Recycle subject to site conditions			Recycle subject to site conditions prior to collection by a licensed collector to be disposed of at the CWTC
General Refuse	170 tonnes	Recycle subject to site conditions			Recycle onsite subject to site conditions prior to disposal to WENT Landfill

Note:

[1] The disposal site of inert C&D materials is subject to the designation by the Public Fill Committee according to DEVB TC(W) No.6/2010.

6.3.2.16 With the implementation of mitigation measures recommended in Section 6.3.3, adverse environmental impacts, including potential hazard, air and odour emissions, noise, wastewater discharge, ecology and public transport, caused by handling, storage, transport and disposal of wastes are not anticipated.

6.3.3 Mitigation Measures

6.3.3.1 The mitigation measures for construction phase are recommended based on the waste management hierarchy principles. Recommendations of good site practices, waste reduction measures as well as the waste storage, collection and transportation are described in the following sub-sections.

Good Site Practices

6.3.3.2 Adverse waste management implications are not expected, provided that good site practices are strictly implemented. The following good site practices are recommended throughout the construction activities:

· Nomination of an approved personnel, such as a site manager, to be responsible for the implementation of good site practices, arrangements for collection and effective disposal to an appropriate facility, of all wastes generated at the site;

· Training of site personnel in site cleanliness, appropriate waste management procedures and concepts of waste reduction, reuse and recycling;

· Provision of sufficient waste disposal points and regular collection for disposal;

· Appropriate measures to minimise windblown litter and dust during transportation of waste by either covering trucks or by transporting wastes in enclosed containers;

· Regular cleaning and maintenance programme for drainage systems, sumps and oil interceptors;

· Provision of wheel washing facilities at site exit before the trucks leave the works areas to minimise dust disturbance due to the trucks transportation to the public road network; and

· The Contractor should prepare a Waste Management Plan (WMP) as part of the Environmental Management Plan (EMP) in accordance with the ETWB TCW No. 19/2005. The WMP should be submitted to the Engineer for approval. Mitigation measures proposed in the EIA Report and the EM&A Manual should be adopted.

Waste Reduction Measures

6.3.3.3 Amount of waste generation can be significantly reduced through good management and control. Waste reduction is best achieved at the planning and design phase, as well as by ensuring the implementation of good site practices. The following recommendations are proposed to achieve reduction:

· Segregate and store different types of waste in different containers, skip or stockpiles to enhance reuse or recycling of materials and their proper disposal;

· Proper storage and good site practices to minimise the potential for damage and contamination of construction materials;

· Plan and stock construction materials carefully to minimise amount of waste generated and avoid unnecessary generation of waste;

· Sort out demolition debris and excavated materials from demolition works to recover reusable/ recyclable portions (i.e. soil, broken concrete, metal, etc.); and

· Provide training to workers on the importance of appropriate waste management procedures, including waste reduction, reuse and recycling.

Storage, Collection and Transportation of Waste

6.3.3.4 Storage of waste on site may induce adverse environmental implications if not properly managed. The following recommendation should be implemented to minimise the impacts:

· Non-inert C&D materials such as top soil should be handled and stored well to ensure secure containment of the materials;

· Stockpiling area should be provided with covers and water spraying system to prevent materials from wind-blown or being washed away; and

· Different locations should be designated to stockpile each material to enhance reuse.

6.3.3.5 The collection and transportation of waste from works areas to respective disposal sites as well as imported fill materials from fill bank to works areas may also induce adverse environmental impacts if not properly managed. The following recommendation should be implemented to minimise the impacts:

· Remove waste in timely manner;

· Employ the trucks with cover or enclosed containers for waste transportation;

· Obtain relevant waste disposal permits from the appropriate authorities;

· Disposal of waste should be done at licensed waste disposal facilities; and

6.3.3.6 All dump trucks engaged on-site for delivery of inert and non-inert C&D material from the site to the designated disposal location, including PFRFs, landfill etc., should be equipped with Global Positioning System (GPS) or equivalent automatic system for real time tracking and monitoring of their travel routings and parking locations by the Contractor to prohibit illegal dumping and landfilling of materials. The data collected by GPS or equivalent system should be recorded properly for checking and analysis the travel routing and parking locations of dump truck engaged on site by the contractor.

6.3.3.7 In addition to the above measures, other specific mitigation measures on handling the C&D materials, chemical waste and general refuse generated from construction phase are recommended in the following sub-sections.

C&D Material

6.3.3.8 C&D materials should be segregated from other wastes subject to site conditions to avoid contamination and ensure acceptability at PFRFs areas or reclamation sites. The following mitigation measures should be implemented in handling the C&D materials:

· Carry out on-site sorting;

· Make provisions in the Contract documents to allow and promote the use of recycled aggregates where appropriate; and

· Implement a trip-ticket system for each works contract in accordance with DEVB TCW No. 06/2010 to ensure that the disposal of C&D materials is properly documented and verified.

6.3.3.9 Details of the recommended on-site sorting and reuse of C&D materials are given below:

a) On-site Sorting of C&D Materials:

- Storage areas would be located within the site during construction phase for temporary storage of inert C&D materials.

- All C&D materials arising from the construction would be sorted on-site to recover the inert C&D materials and reusable and recyclable materials prior to disposal off-site subject to site conditions. Non-inert portion of C&D materials should first be considered to reuse and be disposed of at landfills as a last resort.

- The Contractor would be responsible for devising a system to work for on-site sorting of C&D materials and promptly remove all sorted and processed material arising from the construction activities to minimise temporary stockpiling on-site. It is recommended that the system should include the identification of the source of generation, estimated quantity, arrangement for on-site sorting and/ or collection, temporary storage areas, and frequency of collection by recycling contractors or frequency of removal off-site.

b) Reuse of C&D Materials:

- Based on the construction programme, all inert C&D materials would be best reused on-site during the whole construction phase to minimise off-site handling of inert C&D materials. Should there be any surpluses inert C&D materials necessary for off-site handling, it is recommended to deliver to PFRFs for beneficial reuse in other projects.

Specification of Inert C&D Materials to be Delivered Off-site

6.3.3.10 In case there are surplus inert C&D materials generated in the Project and are required to be delivered to the PFRFs, the inert C&D materials should fulfil the following requirements:

· Reclaimed asphalt pavement should not be mixed with other materials when delivered to the PFRFs;

· Moisture content of inert C&D materials should be lowered to 25% max. when delivered to the PFRFs;

· Inert C&D materials delivered to the PFRFs should be of a size less than 250mm; and

· Inert construction waste should not be in liquid form such that it can be contained and delivered by dump truck instead of tanker truck. Inert C&D materials in liquid form should be solidified before delivering to the PFRFs.

6.3.3.11 Nevertheless, the acceptance criteria of inert C&D materials to PFRFs are subject to the fill management authority of CEDD.

Use of Standard Formwork and Planning of Construction Materials Purchasing

6.3.3.12 Standard formwork should also be used subject to site conditions in order to minimise the arising of non-inert C&D materials. The use of more durable formwork (e.g. metal hoarding) or plastic facing should be encouraged in order to enhance the possibility of recycling. The purchasing of construction materials should be carefully planned in order to avoid over ordering and wastage.

Chemical Waste

6.3.3.13 For those processes which generated chemical waste, it may be possible to find alternatives to eliminate the use of chemicals, to reduce the generation quantities or consider to select a chemical type of less impact on environment, health and safety. Opportunities for the reuse and recycling of materials will be taken subject to site conditions.

6.3.3.14 If chemical wastes are produced at the construction site, the contractors should register with EPD as chemical waste producers. Storage, handling, transport and disposal of chemical waste should be arranged in accordance with the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes published by the EPD. Chemical waste should be stored in appropriate containers and collected by a licensed chemical waste collector. Chemical wastes (e.g. spent lubricant oil) should be considered to recycle at an appropriate facility, while the chemical waste that cannot be recycled should be disposed of at either the CWTC, or another licensed facility, in accordance with the Waste Disposal (Chemical Waste) (General) Regulation.

General Refuse

6.3.3.15 General refuse should be stored in enclosed bins separately from construction and chemical wastes. Recycling bins should also be placed to encourage recycling. Preferably enclosed and covered areas should be provided for general refuse collection and routine cleaning for these areas should also be implemented to keep areas clean. A reputable waste collector should be employed to remove general refuse on a regular basis (i.e. once per day). Arrangements should be made with the recycling companies to collect the recycle waste as required. It is expected that such arrangements would minimise potential environmental impacts.

6.3.3.16 The Contractor should implement an education programme for workers relating to avoiding, reducing, reusing and recycling general waste. Participation in a local collection scheme should be considered by the Contractor to facilitate waste reduction.

6.3.4 Residual Waste Management Implications

6.3.4.1 With the implementation of recommended mitigation measures, adverse residual waste management implications and impacts on potential hazard, air and odour emissions, noise, wastewater discharge and public transport caused by handling (including stockpiling, labelling, packaging & storage), collection, transportation and reuse/ disposal of different types of waste are not anticipated for the construction phase.

6.4 Operational Phase

6.4.1 Assessment Methodology

6.4.1.1 The assessment of waste management implications has been undertaken in accordance with Annexes 7 and 15 of the EIAO-TM and the EIA Study Brief No. ESB-333/2020. The waste management hierarchy comprising avoidance, minimisation, recycling/ reuse, treatment and disposal has also been adopted for the assessment.

Proposal for Waste Management

6.4.1.2 Prior to considering the disposal options for various types of wastes, opportunities for reducing waste generation, on-site or off-site reuse and recycling have been evaluated. After considering the opportunities for reducing waste generation and maximising reuse, the types and quantities of the remaining wastes required to be disposed of have been estimated and the disposal options for each type of wastes have been described. The potential environmental impacts from the management of wastes have been assessed and relevant mitigation measures have been proposed.

6.4.1.3 The details of the assessment methodology could be referred to Section 6.3.1.

Identification and Evaluation of Waste Management Implications

6.4.1.4 As fresh water trunk mains and underground works at Chamber G would be established upon completion of the Project, both of them would be unmanned facilities during operational phase. Therefore, no waste would be anticipated during operational phase.

6.5 Conclusion

6.5.1 Construction Phase

6.5.1.1 Potential waste management implications from the generation of waste during the construction phase have been evaluated. Measures, including the opportunity for on-site sorting, reusing C&D materials etc., are devised in the construction methodology to minimise the surplus materials to be disposed. Recommendations have been made for implementation by the Contractor during the construction period to minimise waste generation and off-site disposal.

6.5.2 Operational Phase

6.5.2.1 Potential waste management implications from the generation of waste during the operational phase have been evaluated. Upon establishment of unmanned facilities, no waste would be anticipated during operational phase.

7 Land Contamination

7.1 Legislation, Standards and Guidelines

7.1.1 General

7.1.1.1 The relevant legislation, standards and guidelines applicable to the present study for the assessment of land contamination include:

· Annex 19 of the EIAO-TM, Guidelines for Assessment of Impact On Sites of Cultural Heritage and Other Impacts (Section 3: Potential Contaminated Land Issues), EPD, 2023;

· Guidance Manual for Use of Risk-Based Remediation Goals (RBRGs) for Contaminated Land Management, EPD, Revised in April 2023;

· Guidance Note for Contaminated Land Assessment and Remediation, EPD, Revised in April 2023; and

· Practice Guide for Investigation and Remediation of Contaminated Land, EPD, Revised in April 2023.

7.1.2 EIAO (Cap. 499), Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM)

7.1.2.1 Under Annex 19 of the EIAO-TM, a number of potentially contaminating historical and present land uses should be considered, including oil installations, gas works, power plants, shipyards, chemical manufacturing /processing plants, metal workshops, car repair and dismantling workshops, municipal solid waste dumping ground, which have the potential to cause or have caused land contamination. Nevertheless, any other potential contaminating activities/ installations/ facilities within the boundary of the Project and the works of the Project should be identified and considered based on professional judgement.

7.1.3 Guidance Manual for Use of RBRGs for Contaminated Land Management

7.1.3.1 The Guidance Manual introduces the risk-based approach in land contamination assessment and presents instructions for comparison of soil and groundwater data to the RBRGs for 54 chemicals of concern (COCs) commonly found in Hong Kong. The RBRGs were derived to suit Hong Kong conditions by following the international practice of adopting a risk-based methodology for contaminated land assessment and remediation and were designed to protect the health of people who could potentially be exposed to land impacted by chemicals under four broad post restoration land use categories. The RBRGs also serve as the remediation targets if remediation is necessary. The RBRGs for soil and groundwater are given in Table 7.1 and Table 7.2 respectively.

Table 7.1 – RBRGs for soil & soil saturation limit

Chemical	Risk-Based Remediation Goals (RBRGs) for Soil				Soil Saturation Limit (Csat) (mg/kg)
	Urban Residential (mg/kg)	Rural Residential (mg/kg)	Industrial (mg/kg)	Public Park (mg/kg)
VOCs
Acetone	9,590	4,260	10,000*	10,000*	***
Benzene	0.704	0.279	9.21	42.2	336
Bromodichloromethane	0.317	0.129	2.85	13.40	1,030
2-Butanone	10,000*	10,000*	10,000*	10,000*	***
Chloroform	0.132	0.0529	1.54	253	1,100
Ethylbenzene	709	298	8,240	10,000	138
Methyl tert-Butyl Ether	6.88	2.80	70.1	505	2,380
Methylene Chloride	1.30	0.529	13.9	128	921
Styrene	3,220	1,540	10,000*	10,000*	497
Tetrachloroethene	0.101	0.0444	0.777	1.84	97.1
Toluene	1,440	705	10,000*	10,000*	235
Trichloroethene	0.523	0.211	5.68	69.4	488
Xylenes (Total)	95.0	36.8	1,230	10,000*	150
SVOCs
Acenaphthene	3,510	3,280	10,000*	10,000*	60.2
Acenaphthylene	2,340	1,510	10,000*	10,000*	19.8
Anthracene	10,000*	10,000*	10,000*	10,000*	2.56
Benzo(a)anthracene	12.0	11.4	91.8	38.3	-
Benzo(a)pyrene	1.20	1.14	9.18	3.83	-
Benzo(b)fluoranthene	9.88	10.1	17.8	20.4	-
Benzo(g,h,i)perylene	1,800	1,710	10,000*	5,740	-
Benzo(k)fluoranthene	120	114	918	383	-
Bis-(2-Ethylhexyl)phthalate	30.0	28.0	91.8	94.2	-
Chrysene	871	919	1,140	1,540	-
Dibenzo(a,h)anthracene	1.20	1.14	9.18	3.83	-
Fluoranthene	2,400	2,270	10,000*	7,620	-
Fluorene	2,380	2,250	10,000*	7,450	54.7
Hexachlorobenzene	0.243	0.220	0.582	0.713	-
Indeno(1,2,3-cd)pyrene	12.0	11.4	91.8	38.3	-
Naphthalene	182	85.6	453	914	125
Phenanthrene	10,000*	10,000*	10,000*	10,000*	28.0
Phenol	10,000*	10,000*	10,000*	10,000*	7,260
Pyrene	1,800	1,710	10,000*	5,720	-
Metals
Antimony	29.5	29.1	261	97.9	-
Arsenic	22.1	21.8	196	73.5	-
Barium	10,000*	10,000*	10,000*	10,000*	-
Cadmium	73.8	72.8	653	245	-
Chromium III	10,000*	10,000*	10,000*	10,000*	-
Chromium VI	221	218	1,960	735	-
Cobalt	1,480	1,460	10,000*	4,900	-
Copper	2,950	2,910	10,000*	9,790	-
Lead	258	255	2,290	857	-
Manganese	10,000*	10,000*	10,000*	10,000*	-
Mercury	11.0	6.52	38.4	45.6	-
Molybdenum	369	364	3,260	1,220	-
Nickel	1,480	1,460	10,000*	4,900	-
Tin	10,000*	10,000*	10,000*	10,000*	-
Zinc	10,000*	10,000*	10,000*	10,000*	-
Dioxins / PCBs
Dioxins (I-TEQ)	0.001	0.001	0.005	0.001	-
PCBs	0.236	0.226	0.748	0.756	-
Petroleum Carbon Ranges
C6 - C8	1,410	545	10,000*	10,000*	1,000
C9 - C16	2,240	1,330	10,000*	10,000*	3,000
C17 - C35	10,000*	10,000*	10,000*	10,000*	5,000
Other Inorganic Compounds
Cyanide, free	1,480	1,460	10,000*	4,900	-
Organometallics
TBTO	22.1	21.8	196	73.5	-
Notes: [1] For Dioxins, the cleanup levels in USEPA Office of Solid Waste and Emergency Response (OSWER) Directive of 1998 have been adopted. The OSWER Directive value of 1 ppb for residential use has been applied to the scenarios of "Urban Residential", "Rural Residential", and "Public Parks", while the low end of the range of values for industrial, 5 ppb, has been applied to the scenario of "industrial". [2] Soil saturation limits for petroleum carbon ranges taken from the Canada-Wide Standards for Petroleum Hydrocarbons in Soil, CCME 2000. [3] * indicates a 'ceiling limit' concentration. [4] *** indicates that the Csat value exceeds the 'ceiling limit' therefore the RBRG applies.

Table 7.2 – RBRGs for groundwater and solubility limit

Chemical	Risk-Based Remediation Goals (RBRGs) for Groundwater			Solubility Limit (mg/L)
	Urban Residential (mg/L)	Rural Residential (mg/L)	Industrial (mg/L)
VOCs
Acetone	10,000*	10,000*	10,000*	***
Benzene	3.86	1.49	54.0	1,750
Bromodichloromethane	2.22	0.871	26.2	6,740
2-Butanone	10,000*	10,000*	10,000*	***
Chloroform	0.956	0.382	11.3	7,920
Ethylbenzene	1,020	391	10,000*	169
Methyl tert-Butyl Ether	153	61.1	1,810	***
Methylene Chloride	19.0	7.59	224	***
Styrene	3,020	1,160	10,000*	310
Tetrachloroethene	0.250	0.0996	2.95	200
Toluene	5,110	1,970	10,000*	526
Trichloroethene	1.21	0.481	14.2	1,100
Xylenes (Total)	112	43.3	1,570	175
SVOCs
Acenaphthene	10,000	7,090	10,000*	4.24
Acenaphthylene	1,410	542	10,000*	3.93
Anthracene	10,000*	10,000*	10,000*	0.0434
Benzo(a)anthracene	-	-	-	-
Benzo(a)pyrene	-	-	-	-
Benzo(b)fluoranthene	0.539	0.203	7.53	0.0015
Benzo(g,h,i)perylene	-	-	-	-
Benzo(k)fluoranthene	-	-	-	-
Bis-(2-Ethylhexyl)phthalate	-	-	-	-
Chrysene	58.1	21.9	812	0.0016
Dibenzo(a,h)anthracene	-	-	-	-
Fluoranthene	10,000*	10,000*	10,000*	0.206
Fluorene	10,000*	10,000*	10,000*	1.98
Hexachlorobenzene	0.0589	0.0234	0.695	6.20
Indeno(1,2,3-cd)pyrene	-	-	-	-
Naphthalene	61.7	23.7	862	31.0
Phenanthrene	10,000*	10,000*	10,000*	1.00
Phenol	-	-	-	-
Pyrene	10,000*	10,000*	10,000*	0.135
Metals
Antimony	-	-	-	-
Arsenic	-	-	-	-
Barium	-	-	-	-
Cadmium	-	-	-	-
Chromium III	-	-	-	-
Chromium VI	-	-	-	-
Cobalt	-	-	-	-
Copper	-	-	-	-
Lead	-	-	-	-
Manganese	-	-	-	-
Mercury	0.486	0.184	6.79	-
Molybdenum	-	-	-	-
Nickel	-	-	-	-
Tin	-	-	-	-
Zinc	-	-	-	-
Dioxins / PCBs
Dioxins (I-TEQ)	-	-	-	-
PCBs	0.433	0.171	5.11	0.031
Petroleum Carbon Ranges
C6 - C8	82.2	31.7	1,150	5.23
C9 - C16	714	276	9,980	2.80
C17 - C35	12.8	4.93	178	2.80
Other Inorganic Compounds
Cyanide, free	-	-	-	-
Organometallics
TBTO	-	-	-	-
Notes: [1] Blank indicates that RBRG could not be calculated because the toxicity or physical/chemical values were unavailable, or the condition of Henry's Law Constant>0.00001 was not met for the inhalation pathway. [2] Water solubilities for Petroleum Carbon Range aliphatic C9-C16 and greater than C16 generally are considered to be effectively zero and therefore the aromatic solubility for C9-C16 is used. [3] * indicates a 'ceiling limit' concentration. [4] *** indicates that the solubility limit exceeds the 'ceiling limit' therefore the RBRG applies.

7.1.4 Guidance Note for Contamination Land Assessment and Remediation

7.1.4.1 In accordance with EPD’s Guidance Note for Contamination Land Assessment and Remediation, a contamination assessment evaluation should:

· Provide a clear and detailed account of the present land use and the relevant past land history, in relation to possible land contamination;

· Identify areas of potential contamination and associated impacts, risks or hazards; and

· Submit a plan to evaluate the actual contamination conditions for soil and/or groundwater, if required.

7.1.5 Practice Guide for Investigation and Remediation of Contaminated Land

7.1.5.1 The EPD’s Practice Guide for Investigation and Remediation of Contaminated Land includes a summary of the general steps of a contamination assessment study, which include site appraisal, site investigation and remediation.

7.2 Assessment Methodology

7.2.1 Overview

7.2.1.1 The land contamination assessment has been conducted according to the following procedures. Summary of findings are further discussed in the following sections.

· Desktop review of the site history; and

· Site survey to identify any potentially contaminated areas;

7.2.1.2 A Land Contamination Review (LCR) was prepared:

· To provide an account of the present land use within the assessment area and relevant past land use history in relation to possible land contamination;

· To identify areas of potential contamination and the associated impacts, risks or hazards; and

· To identify the COCs and scoping of requirements for sampling and laboratory testing of soil and groundwater samples if required.

7.2.1.3 The LCR report was submitted to EPD in February 2024. The agreed LCR report is provided in Appendix 7.1.

7.2.2 Assessment Area

7.2.2.1 According to Section 1, the proposed fresh water trunk mains would run through Conservation Area (CA). In addition, the modification works at Chamber G including the proposed access tunnels, bypass tunnels and chambers are underground works which would fall within the underground stratum of Lam Tsuen Country Park and CA.

7.2.2.2 Therefore, the concerned works areas within the boundary of the Project (hereinafter referred to as “assessment areas”) to be reviewed and assessed in Land Contamination Assessment include the following:

· Proposed fresh water trunk mains works areas; and

· Proposed modification works area of Chamber G.

7.2.2.3 Locations of the assessment areas are shown in Figure 1.1 of the LCR in Appendix 7.1. The works areas of modification works of Chamber G are located within a rural area in Ngau Tam Mei, while a portion of proposed fresh water trunk mains stretches from Ngau Tam Mei Water Treatment Works (NTM WTW) to Ngau Tam Mei Fresh Water Primary Service Reservoir (NTM FWPSR) and another portion between Ching Yau Road and San Tam Road.

7.3 Description of the Environment

7.3.1 Aerial Photographs and Historical Land Use

7.3.1.1 Selected historical aerial photographs showing the assessment areas between Year 1978 and Year 2021 have been reviewed in order to ascertain any historical landuses with the potential for land contamination. The findings of the selected historical aerial photographs of the area are summarised in Table 7.3. The aerial photographs showing the historical conditions of the site are presented in Appendix A of Appendix 7.1.

Table 7.3 – Summary of historical aerial photographs for the area within the Assessment Areas

Year	Description
	Chamber G	Fresh Water Trunk Mains
1978	This site area was occupied by natural vegetation.	The alignment from NTM WTW to NTM FWPSR was occupied by natural vegetation while some agricultural land was observed at the alignment between Ching Yau Road and San Tam Road.
1988	Land uses at this site remained unchanged as compared with Year 1978.	Construction of access road from NTM WTW to NTM FWPSR was observed along the alignment from NTM WTW to NTM FWPSR. No significant changes at the alignment between Ching Yau Road and San Tam Road was observed as compared with Year 1978.
1997	Land uses at this site remained unchanged as compared with Year 1988.	Land uses at the alignment from NTM WTW to NTM FWPSR remained unchanged as compared with Year 1988. Agricultural land previously observed at the alignment between Ching Yau Road and San Tam Road was left vacant and returned to natural vegetation.
2001	Land uses at this site remained unchanged as compared with Year 1997.	Access road from NTM WTW to NTM FWPSR was established. No significant changes at the alignment between Ching Yau Road and San Tam Road was observed as compared with Year 1997.
2010	Land uses at this site remained unchanged as compared with Year 2001.	Land uses at both alignments remained unchanged as compared with Year 2001.
2022	Land uses at this site remained unchanged as compared with Year 2010.	Land uses at both alignments remained unchanged as compared with Year 2010.

7.3.2 Site Geology

7.3.2.1 With reference to the San Tin and Yuen Long Solid and Superficial Geology (1:20,000 map) (Series: HGM20) published by the Geotechnical Control Office, Civil Engineering Services Department, the area near Chamber G is covered by alluvium, terraced alluvium and rhyolite lava, and the fresh water trunk mains alignment falls on area covered by alluvium, terraced alluvium, debris flow deposits, rhyolite lava and slope debris.

7.3.2.2 Besides, a review of the following previous ground investigation (GI) report for GI works undertaken at and in vicinity of the proposed works areas in Chamber G was conducted to obtain information about the geological conditions of these areas:

· Ground Investigation – Phase 1 (Drillholes) for Works Order No. GE/93/08.56, Additional Treatment and Transfer Facilities for North Western New Territories, Ngau Tam Mei Treatment Works, CED Contract No. GE/93/08, by Lam Geotechnics Limited (1995) (Civil Engineering and Development Department’s (CEDD) Geotechnical Information Unit Report No. 20588).

7.3.2.3 With reference to the above GI Report, the materials encountered during the GI works comprise fill material, debris flow deposits, alluvium and tuff. The area near Chamber G is generally covered by layers of alluvium and coarse ash tuff (from completely, moderately to slightly decomposed) was encountered underneath.

7.3.3 Site Surveys

7.3.3.1 Site surveys were conducted in June 2023. The findings of the site surveys are provided in Table 7.4 and the site survey photographs are presented in Appendix B of Appendix 7.1. It should be noted that the Chamber G works area was fenced during site survey and is currently occupied by vegetation. Besides, the area between Ching Yau Road and San Tam Road is also occupied by natural vegetation. Thus, land contamination due to current land uses at these areas are unlikely.

Table 7.4 - Summary of current land uses observed during the site survey

Location	Description
Chamber G	The Chamber G works area was fenced during site survey. Natural vegetation was observed from peripherical observation (Photo 1 in Appendix B of Appendix 7.1).
Fresh Water Trunk Mains Alignment	The alignment from NTM WTW to NTM FWPSR was mainly occupied by public roads and natural vegetation at the road kerb observation (Photo 2-7 in Appendix B of Appendix 7.1). No land contaminating activities or sources were observed. The alignment between Ching Yau Road and San Tam Road is inaccessible and natural vegetation was observed from peripherical observation (Photo 8 in Appendix B of Appendix 7.1). Given that the alignment is currently occupied by natural vegetation, presence of land contaminating sources and activities is not anticipated. Therefore, land contamination along the fresh water trunk mains within CA due to current land use is unlikely.

7.3.4 Information from Relevant Government Departments

Fire Services Department

7.3.4.1 Information requests have been sent to Fire Services Department (FSD) to enquire:

· Records of Dangerous Goods (DGs) License issued in the assessment area which covered the records of spillage/leakage of Dangerous Goods;

· Any past and present information related to the use and/ or storage of DGs in the assessment area; and

· Past and present incident records in the assessment area.

7.3.4.2 Based on the information provided by FSD in August 2023, no incident record was found within the Assessment Areas. A total of 7 DGs Licenses have been issued within the NTM WTW which are out of the assessment area. A copy of FSD’s correspondence is provided in Appendix C of Appendix 7.1.

Environmental Protection Department

7.3.4.3 Information requests have been sent to EPD to enquire:

· The records of Chemical Waste Producers Registration (CWPR) in the assessment area; and

· Past and present chemical spillage/ leakage records in the assessment area.

7.3.4.4 Based on the information provided by EPD in June 2023, there is no chemical spillage accident records within the assessment areas. Besides, no records of CWP registration within the assessment area was found at EPD’s Register of Chemical Waste Producers. A copy of EPD’s correspondence is provided in Appendix D of Appendix 7.1.

7.4 Future Land Use

7.4.1.1 The RBRGs have developed four different post-restoration land uses, namely “Urban Residential”, “Rural Residential”, “Industrial” and “Public Parks”, to reflect actual settings which people could be exposed to contaminated soil or groundwater. Definitions of post-restoration land uses are given in EPD’s Guidance Manual for Use of Risk-Based Remediation Goals for Contaminated Land Management.

7.4.1.2 As the proposed water mains and modification works will form part of the NTM WTW and NTM FWPSR in support of their operation during the operational phase of the Project, the “Industrial” land use is considered as future land use for this assessment.

7.5 Identification of Potentially Contaminated Site

7.5.1.1 Based on the desktop review findings of selected aerial photographs, site survey findings, natural vegetation and existing road were observed with no land contamination issue identified within the assessment area. Besides, no DGs records, incidents and chemical spillage accidents were reported within the assessment area from relevant government departments including FSD and EPD. In conclusion, no potentially contaminated areas are identified within the assessment area, which includes the Project as shown in Figure 1.1 of Appendix 7.1. No land contamination issue is anticipated in the Project, and environmental SI works are not required.

7.6 Conclusion and Recommendation

7.6.1.1 This land contamination assessment examined the potential contaminative land uses within the assessment area and their potential impacts to future use. The assessment involved desktop review, site surveys and identification of potentially contaminated area, etc.

7.6.1.2 Based on desktop review findings, the information collected during the site surveys and from relevant government departments, no land contamination issues within the assessment area are anticipated, hence environmental SI works are not required. Preparation and submission of Contamination Assessment Plan (CAP), Remediation Action Plan (RAP) and Remediation Report (RR) are therefore not necessary.

7.6.1.3 As no future works would be conducted within the assessment area (i.e. Chamber G and fresh water trunk mains alignment within CA) before commencement of this Project while major construction works for the Project are anticipated to commence in Year 2025, site re-appraisal is therefore not required prior to the commencement of the construction.

7.6.1.4 Based on the information above, no land contamination impacts are identified for the Project. No further site investigation and land contamination assessment are required for the Project.

8 Ecological Impact (Terrestrial and Aquatic)

8.1 Legislation, Standards and Guidelines

8.1.1 Local Legislation, Standards and Guidelines

8.1.1.1 The relevant local legislation, standards and guidelines applicable to the present study for the assessment of ecological impact include:

· Forests and Countryside Ordinance (Cap. 96) and its subsidiary legislation, the Forestry Regulations (Cap. 96A);

· Wild Animals Protection Ordinance (Cap. 170);

· Country Parks Ordinance (Cap. 208) and its subsidiary legislation;

· Environmental Impact Assessment Ordinance (EIAO) (Cap. 499) and the associated Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM);

· Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586) and its subsidiary legislation;

· EIAO Guidance Note (GN) No. 6/2010 – Some Observations on Ecological Assessment from the Environmental Impact Assessment Ordinance Perspective;

· EIAO GN No. 7/2010 – Ecological Baseline Survey for Ecological Assessment;

· EIAO GN No. 10/2010 – Methodologies for Terrestrial and Freshwater Ecological Baseline Surveys;

· Hong Kong Planning Standards and Guidelines (HKPSG);

· Planning, Environment & Lands Branch Technical Circular (PELBTC) No. 1/97/Works Branch Technical Circular (WBTC) No. 4/97 – Guidelines for Implementing the Policy on Off-site Ecological Mitigation Measures;

· Environment, Transport and Works Bureau Technical Circular (Works) (ETWB TCW) No. 5/2005 – Protection of Natural Streams/Rivers from Adverse Impact Arising from Construction Works;

· Hong Kong Biodiversity Strategy and Action Plan (2016-21); and

· Lists of Wild Animals and Plants under State Protection.

8.1.2 International Conventions and Guidelines

8.1.2.1 International conventions and guidelines potentially relevant include:

· Convention on International Trade in Endangered Species of Wild Fauna and Flora (“CITES”); and

· United Nations Convention on Biological Diversity.

8.2 Methodology

8.2.1 Assessment Area

8.2.1.1 The assessment area for terrestrial and aquatic ecological field surveys included all area within 500m from the boundary of the Project, as well as any other areas likely to be impacted by the Project. The 500m assessment area is illustrated in Figure 8.1.

8.2.2 General

8.2.2.1 The ecological baseline study observed and followed the requirements in establishing the ecological baseline profile and the requirements of the pertinent of Annexes 8 and 16 of the EIAO-TM as well as EIAO GN No. 7/2010, No. 10/2010 and No. 11/2010.

8.2.3 Literature Review

8.2.3.1 Desktop literature review on the existing ecological baseline condition were carried out upon commencement of the study. Findings of relevant studies or surveys, including but not limited to relevant Environmental Impact Assessment (EIA) reports, newsletter related to local ecology and conservation (such as Hong Kong Biodiversity by Agriculture, Fisheries, and Conservation Department (AFCD) and Connections by Kadoorie Farm and Botanic Garden (KFBG)), published scientific papers, as well as the Biodiversity Database and other publications on the conservation status and distribution of local flora and fauna, etc.

8.2.3.2 All available information were collated and evaluated to identify any information gap relevant to the establishment of the ecological profile of the terrestrial environment, and to determine the ecological surveys needed for an ecological impact assessment.

8.2.3.3 In particular, the EIA Reports for the following projects were reviewed. The assessment area boundary of the reviewed EIA studies is presented in Figure 8.1a.

· Ramboll. 2016. Proposed Low-rise and Low-density Residential Development at Various Lots and their Adjoining Government Land in D.D. 104, East of Kam Pok Road, Mai Po, Yuen Long. N.T. (AEIAR-205/2017);

· AECOM. 2009. Hong Kong Section of Guangzhou - Shenzhen - Hong Kong Express Rail Link (AEIAR-143/2009)

8.2.3.4 Based on the literature review, there is a lack of existing ecological information in the Ngau Tam Mei (NTM) area, i.e. the valley between Ngau Tam Shan and Kai Kung Shan. It is considered that this paucity of relevant ecological records constitutes an information gap. To fill this information gap, survey transects had been set specifically in this area to investigate the existing ecological baseline conditions.

8.2.4 Ecological Field Surveys

General

8.2.4.1 The methodology of the ecological field surveys followed the requirements and recommendations provided in the technical guidelines of ecological assessment in Annexes 8 and 16 of EIAO-TM, and the EIAO GN (No. 7/2010 and No. 10/2010). Survey transects were set to cover all identified habitat type within the assessment area.

8.2.4.2 All ecological field surveys were carried out in a manner that would not cause any unnecessary stress or damage to any species or habitats. Permission under the Wild Animal Protection Ordinance (Cap. 170) for using hand-nets and traps during the field surveys had been obtained from AFCD prior to the surveys.

8.2.4.3 During the surveys, photographs of floral and faunal species of conservation importance were taken for record as far as practicable.

Survey Programme

8.2.4.4 In accordance to the requirements set out in the EIA Study Brief (ESB-333/2020), ecological surveys were carried out from January to June 2022, covering both the dry and the wet season. A survey programme is presented in Table 8.1 below:

Table 8.1 – Ecological survey programme

Ecological Surveys	2022
	Dry Season				Wet Season
	Jan	Feb	Mar	Apr		May	Jun
Habitat and Vegetation	✓				✓
Mammals	✓	✓	✓	✓		✓	✓
Avifauna	✓	✓	✓	✓		✓	✓
Herpetofauna	✓	✓	✓	✓		✓	✓
Butterflies	✓	✓	✓	✓		✓	✓
Odonates	✓	✓	✓	✓		✓	✓
Freshwater Community	✓				✓

Habitat and Vegetation

8.2.4.5 The information gathered from the literature review and recent aerial photographs were used for the preparation of a preliminary habitat map of the assessment area, which was then verified during the ecological field surveys, and amended where necessary based on the findings from the surveys. Particular attention was given to habitats of conservation interest.

8.2.4.6 Habitats were identified and characterised with reference to size, vegetation type, flora species present, dominant species, species diversity and abundance, community structure, as well as the presence of any feature of ecological importance. Habitats identified were illustrated on a habitat map of an appropriate scale (e.g. 1:1000 to 1:5000) to show the distribution and coverage of each habitat type.

8.2.4.7 Representative photographs of each habitat identified were taken and presented in Appendix 8.1. Recognised sites or habitats of conservation importance were highlighted and discussed.

8.2.4.8 Vegetation survey was conducted once per season via transects that were set across representative patches of each habitat type identified within the assessment area. The survey transects are presented in Figure 8.1. Floral species observed during the surveys were identified to species level as far as practicable, with their relative abundance recorded and presented.

Terrestrial Mammals

8.2.4.9 Terrestrial mammal surveys were carried out monthly during the field survey period. Both daytime and night-time surveys were conducted via set transects. The survey transects are presented in Figure 8.1.

8.2.4.10 As most mammalian species in Hong Kong occur at low densities, surveys for mammals included both direct observation and active searching for signs of mammal occurrence (including potential roost, footprints and droppings).

8.2.4.11 With regards to bats, a search of potential roost sites was made within the Project boundary. Evening surveys were conducted using a bat detector, targeting potential areas for roosting and/or foraging bats.

8.2.4.12 Nomenclature of species follows the Hong Kong Biodiversity Database.

Avifauna

8.2.4.13 Surveys for birds were conducted monthly by transect count with the aid of a pair of binoculars at a suitable time (usually in early morning) when birds are most active. The survey transects are presented in Figure 8.1.

8.2.4.14 Both day-time and night-time surveys were conducted. Avifauna species were detected either by direct sighting or by their calls. Species recorded were identified and quantified, with special reference to behaviours such as roosting and breeding.

8.2.4.15 Nomenclature of species follows the updated List of Hong Kong Birds published by the Hong Kong Bird Watching Society.

Herpetofauna

8.2.4.16 Surveys for herpetofauna species were conducted monthly by transect count during the field survey period. Daytime surveys were conducted. The survey transects are presented in Figure 8.1.

8.2.4.17 Since many herpetofauna species in Hong Kong are nocturnal, night-time surveys were also conducted. Amphibian and reptile species were detected by direct sighting, species-specific calls, as well as other signs such as shredded skin that allow species identification. Owing to their cryptic nature, all potential micro-habitats (e.g. stones, crevices or rotten log) were checked or uncovered to reveal the presence of any hidden animals. With regards to amphibians, active searching for their eggs and tadpoles in aquatic habitats were also conducted to indicate any breeding activities.

8.2.4.18 Nomenclature of species follows the Hong Kong Biodiversity Database.

Butterflies

8.2.4.19 Surveys for butterflies were conducted monthly via transects, with species mainly detected by direct observation. The survey transects are presented in Figure 8.1.

8.2.4.20 Active searching for larvae and pupae within 5m of the set transects was conducted. All butterflies observed were identified to species level and quantified. Species occurring outside 5m of the set transects but within the assessment area were also recorded. The surveys were conducted at suitable weather condition to avoid cold and/or overcast weather when most butterflies are less active.

8.2.4.21 Nomenclature of species follows the Hong Kong Biodiversity Database.

Odonates

8.2.4.22 Surveys for dragonflies shall be conducted monthly via transects, with species detected by direct observation. The survey transects are presented in Figure 8.1. Survey transects were set with special attention on streams and other water bodies.

8.2.4.23 All dragonflies observed were identified to species level and quantified. Species occurring outside 5m of the set transects but within the assessment area were also recorded. The surveys were conducted at suitable weather conditions to avoid cold and/or overcast weather when most dragonflies are less active.

8.2.4.24 Nomenclature of species follows the Hong Kong Biodiversity Database.

Freshwater Community

8.2.4.25 Surveys for freshwater fish and aquatic invertebrates were conducted once in the dry season and once in the wet season during the survey period. Surveys were carried out at representative sampling locations (see Figure 8.1), with special attention to aquatic habitats, particularly permanent watercourses. Descriptions and photographic records of the freshwater community survey locations are provided in Appendix 8.2.

8.2.4.26 Surveys were undertaken when the watercourses were not in spate and the weather was not too cold. Surveys were carried out by bankside transect count (aided by a pair of binoculars), hand-netting method or use of baited fish traps, or a combination of these methods, depending on the actual on-site conditions.

8.2.4.27 Regarding aquatic invertebrates, surveys shall be carried out by kick sampling method at stream riffles in wadable channels, and by sweeping of hand-nets at submerged or marginal vegetation and macrophytes (if present) to collect macroinvertebrates in deeper water margins.

8.2.4.28 Freshwater fishes and aquatic invertebrates recorded were identified and the relative abundance of each species will be estimated.

8.2.4.29 Nomenclature of species follows the Hong Kong Biodiversity Database.

8.3 Ecological Baseline Conditions

8.3.1 Recognised Sites of Conservation Importance

8.3.1.1 Figure 8.2 presents the locations of recognised sites of conservation importance within or near the 500m assessment area.

Lam Tsuen Country Park

8.3.1.2 Designated in Year 1979, the Country Park encompasses about 1,520 ha spanning from Tai Po, Fanling, to Yuen Long. Lam Tsuen Country Park is divided into two parts, Tai To Yan, and Kai Kung Leng, near Fan Kam Road.

8.3.1.3 The hillside woodlands in Lam Tsuen Country Park are home to a host of wild animals such as mammals (East Asian Porcupine, Small-toothed Ferret Badger, Small Indian Civet, Masked Palm Civet, Chinese Pangolin, Leopard Cat and Rhesus Macaque), birds (Chinese Bulbul, Red-whiskered Bulbul, and White-backed Munia) and butterflies (Common Mormon, Grass Yellow, Red Helen, Great Orange Tip, Rustic, Great Mormon, Lemon Emigrant, and Peacock Pansy). The woodlands also support diverse dragonflies and insects, as well as many trees.

8.3.1.4 As illustrated in Figure 8.2, Lam Tsuen Country Park is located approximately 200m to the south of the existing Ngau Tam Mei Water Treatment Works (NTM WTW). The modification works at Chamber G including the proposed access tunnels, bypass tunnels and chambers are underground works, which would fall within the underground stratum of Lam Tsuen Country Park. Part of the proposed fresh water trunk mains between NTM WTW and Ngau Tam Mei Fresh Water Primary Service Reservoir (NTM FWPSR) are also aligned along the fringe of Lam Tsuen Country Park.

Mai Po Inner Deep Bay Ramsar Site and Mai Po Nature Reserve

8.3.1.5 About 1,500 ha of wetland in the Mai Po and Inner Deep Bay region has been listed as a Ramsar Site under the Ramsar Convention since 4th September 1995. The site has a shallow bay with extensive intertidal mudflats backed by mangroves, tidal shrimp ponds (gei wais), commercial fishponds and reedbeds.

8.3.1.6 The site serves as an important over-wintering and refuelling station site for the waterbirds along the East Asian-Australasian Flyway. About 400 species, representing around 70% of the Hong Kong birds, have been recorded there. The site regularly supports 50,000 to 80,000 waterbirds in winter, including a number of globally threatened species, such as Black-faced Spoonbill, Saunders's Gull and Nordmann's Greenshank.

8.3.1.7 The Mai Po Marshes and the Inner Deep Bay area were also designated as Sites of Special Scientific Interest (SSSI) in 1976 and 1986, respectively. The Mai Po Marshes SSSI covers an area of about 393 ha, while the Inner Deep Bay SSSI is approximately 1,036 ha in size.

8.3.1.8 Part of the Mai Po Marshes SSSI, largely the gei wais, was designated as Mai Po Nature Reserve (MPNR) and has been actively managed by World Wide Fund for Nature Hong Kong since 1983 for conservation and education purposes.

8.3.1.9 The Mai Po Inner Deep Bay Ramsar Site, MPNR, and associated SSSIs all fall outside of the 500m assessment area (see Figure 8.2).

8.3.1.10 An approximately 1,011.6 ha of land in the Deep Bay area comprised mainly of commercial fishponds is designated as a Priority Site for Enhanced Conservation (namely Deep Bay Wetland Outside Ramsar Site) under the New Nature Conservation Policy drawn up in 2004. This site falls outside of the 500m assessment area (see Figure 8.1).

Wetland Conservation Area (WCA) and Wetland Buffer Area (WBA)

8.3.1.11 To conserve the ecological value of the Ramsar site and prevent habitat fragmentation from development, the Town Planning Board adopts a two-pronged approach to land use planning control through the designation of WCA and WBA.

8.3.1.12 The WCA basically covers the existing contiguous and adjoining active or inactive fishponds in the landward part of the Ramsar Site with the planning intention to conserve the ecological value of the fishponds which form an integral part of the wetland ecosystem in the Deep Bay area.

8.3.1.13 A strip of land of about 500m wide along the landward side of the WCA is designated as the WBA to protect the ecological integrity of the fishponds and wetlands within the WCA and to prevent developments that would have a negative off-site impact on the ecological value of fishponds.

8.3.1.14 A small part of the 500m assessment area to the west of Long Ha overlaps with WBA (see Figure 8.2).

Conservation Area (CA)

8.3.1.15 A number of areas scattered across the 500m assessment area fall under the zoning of CA (see Figure 8.2). Some sections of the proposed freshwater trunk main are located within these CAs. This zoning is intended to protect and retain the existing natural landscape, ecological or topographical features of the area for conservation, educational and research purposes.

8.3.2 Habitat and Vegetation

Literature Review

8.3.2.1 Major habitats present in the 500m assessment area included agriculture, pond, watercourse, shrubland, secondary woodland, plantation and developed/village area.

8.3.2.2 Small patches of agricultural lands were scattered in the NTM area. Different types of agriculture, including active and abandoned farmlands, orchards, were present. Dominant vegetation in this habitat comprised mainly exotic crops, fruit trees and self-seeded grasses.

8.3.2.3 The majority of ponds, which served for aquacultural uses, were situated in the NTM area. A few small irrigation ponds were found within the agricultural areas. Very limited floral diversity was recorded in this habitat.

8.3.2.4 A major channelised watercourse, i.e. the NTM channel, is located near but outside of the 500m assessment area. Watercourses present within the 500m assessment area were mainly semi-natural watercourses located in the hillsides around NTM WTW and NTM FWPSR. Floral richness is very limited in this habitat.

8.3.2.5 Shrubland were located in the hillside around NTM and near the southwestern end of the proposed fresh water trunk mains. This habitat was dominated by native, pioneer shrubs, grasses and herbaceous species. No closed canopy layer was formed.

8.3.2.6 A few small-sized secondary woodlands were located in the village areas within the 500m assessment area. All of them were patchy and isolated from the hillside. Each canopy layer of these woodlands was similarly formed by mature fruit trees and several native tree species.

8.3.2.7 Patches of plantation were found mainly on the engineering slopes adjacent to the shrublands present in the 500m assessment area. The vegetation composition of this habitat was simple with a canopy layer formed by exotic trees such as Acacia spp. and Eucalyptus spp. Regeneration of native vegetation in the understory was limited.

8.3.2.8 Developed area covered a considerable part of the 500m assessment area. It primarily comprised residential area, brownfield sites and wastelands in the Long Ha and Ngau Tam Mei areas. Vegetation in this habitat was dominated by exotic roadside and village planting.

8.3.2.9 One species of conservation importance, Aquilaria sinensis, were recorded within the 500m assessment area (AECOM 2009). Several individuals of the species were recorded from shrubland and plantation in Ngau Tam Mei (AECOM 2009). The species is assessed as Vulnerable nationally and globally (Qin et al. 2017 and IUCN 2022), and is listed under state protection (Category II) in China and Cap. 586 in Hong Kong. Nevertheless, Aquilaria sinensis is commonly found in lowland forests and fung shui woods in Hong Kong (Corlett et al. 2000).

Survey Findings

8.3.2.10 A total of 9 habitat types was identified in the assessment area, i.e. natural watercourse, artificial pond, modified watercourse, grassland, shrubby grassland, shrubland, woodland, plantation, and developed area. The habitat map is shown in Figure 8.3. Classification and definition of habitat types was based on Kwong et al. (2022).

8.3.2.11 Representative photographic records of habitat identified are provided in Appendix 8.1. The area/length covered of each habitat type is presented in Table 8.2 below.

Table 8.2 – Habitat Types Identified within the Assessment Area

Habitat Type	Area (ha)
	Within Project Elements ^[1]Assessment Area			Within Assessment Area
	Freshwater Trunk Main between Ching Yau Road and San Tam Road	Freshwater Trunk Main between NTM WTW and NTM FWPSR	Proposed Modification of Chamber G
Natural Watercourse	-	0.003	-	10.62 (km)
Artificial Pond	-	-	-	7.15
Modified Watercourse	-	-	-	6.83 (km)
Grassland	-	-	-	7.53
Shrubby Grassland	-	-	-	17.81
Shrubland	-	-	-	15.74
Woodland	0.09	0.06	0.38	187.82
Plantation	-	0.03	0.02	26.75
Developed Area	-	0.22	-	58.38
Remark: [1] Habitats recorded within the project boundary of modification of Chamber G are included in the calculation.

8.3.2.12 A total of 153 flora species was recorded within the assessment area during the surveys. These species were commonly recorded in woodland and plantation habitats. Vegetation communities showed varied growth forms, but the most common ones are trees and herbs.

8.3.2.13 The assemblage is composed of more or less equal number of native and exotic species. Generally, the plant species recorded were either common or cultivated in Hong Kong.

8.3.2.14 Four floral species of conservation importance, i.e., Aquilaria sinensis, Camellia euryoides, Cibotium barometz, and Gnetum luofuense were recorded. A complete list of flora species recorded within the assessment area are attached in Appendix 8.3 (Appendix 8.3a shows the List of Floral Species Recorded within the 500m Assessment Area and Appendix 8.3b shows the List of Floral Species Recorded within the Project Area).

Natural Watercourse

8.3.2.15 Natural watercourses refer to rivers and streams experiencing natural flow patterns in unchannelised watercourse beds and banks.

8.3.2.16 This habitat type stretches approximately 10.62 km within the assessment area, which includes perennial and seasonal streams that are generally limited to the hillslopes close to the NTM WTW and the village areas in NTM. The natural streams on the hillslopes close to the NTM WTW are mostly ephemeral in nature and have dried up. These seasonal streams are mainly vegetated with fern species such as Lygodium japonicum and Macrothelypteris torresiana. Meanwhile, the perennial streams that stretch to the village areas in NTM are dominated with Alocasia macrorrhizos with adjacent Macaranga tanarius var. tomentosa, Mangifera indica and Dimocarpus longan trees. Perennial streams located east of the NTM WTW and approximately 560m from NTM FWPSR were also noted during the surveys. No fauna species, however, was recorded in natural watercourses within the assessment area during the surveys.

8.3.2.17 Approximately 0.003 km of this habitat intercepts with the Project Site which is mainly limited to the stream channels that are along the Ching Yau Road close to NTM WTW. This section of natural watercourse was also observed to have dried up. No fauna and flora species were recorded in this area during the surveys.

8.3.2.18 Meanwhile, some sections of natural watercourse (approximately 4.32 km) are within the Lam Tsuen Country Park. The riparian areas of seasonal streams are dominantly overgrown with fern species such as Dicranopteris pedata and M. torresiana. Meanwhile the riparian areas of perennial streams within Lam Tsuen Country Park are covered with A. macrorrhizos.

Modified Watercourse

8.3.2.19 Modified watercourses are channelised rivers and streams, which are often without natural banks and beds, and are not subject to natural flow patterns.

8.3.2.20 Some modified watercourses, i.e. minor channelised watercourses, drainage channels, and water ditches, traverse about 6.83 km of the assessment area. Ditches provide habitat for some reptile species, i.e., Gekko chinensis, Hemidactylus bowringii, Hemidactylus garnotii, Indotyphlops braminus, Lycodon capucinus and Trimeresurus albolabris. Additionally, majority of the amphibians recorded during the surveys were likewise observed on ditches along Ching Yau Road particularly the section in between NTM WTW and NTM FWPSR. Other channelised watercourse and minor channelised watercourse, on the other hand, were commonly inhabited by aquatic invertebrates such as Enithares sp., Pomacea canaliculata and Melanoides tuberculata and dragonfly species such as Orthetrum glaucum, Orthetrum pruinosum and Orthetrum sabina sabina. Riparian sections of these modified watercourses are mostly covered with sedges and herbs i.e., Cyperus malaccensis, A. macrorrhizos, Bidens alba, Cocculus orbiculatus, Mikania micrantha, Pteris multifida and Wedelia trilobata.

8.3.2.21 2 species of conservation importance, the amphibian Kalophrynus interlineatus and reptile L. capucinus, were recorded in the modified watercourses within the assessment area during the surveys.

Artificial Pond

8.3.2.22 Artificial ponds are small artificial water bodies constructed for aquaculture, and ecological mitigation purpose.

8.3.2.23 A total of 9 pond features (eight active and one abandoned), approximately 7.15 ha, are within the assessment area. Majority of these artificial ponds are in NTM village, privately owned, and appeared to be actively managed either for leisure, nursery, and self-consumption purposes. A total of 7 vegetation species were recorded in artificial ponds during the surveys i.e., Cyperus haspan, Ipomoea cairica, Ipomoea triloba, Mikania micrantha, Nymphaea nouchali, Typha angustifolia, and Phragmites australis.

8.3.2.24 No species of conservation importance was recorded in the artificial ponds within the assessment area during the surveys.

Grassland

8.3.2.25 Grasslands are rural lands mainly covered by grass species.

8.3.2.26 This habitat type covers about 7.53 ha of the assessment area and were noted on hillside area in NTM village, Long Ha and the hillside grasslands adjacent to Kai Kung Leng hiking trail. These grasslands are dominated with Dicranopteris pedata and Miscanthus sinensis. Approximately 6.50 ha of grassland identified is located within the Lam Tsuen Country Park, and is likewise dominated by fern D. pedata and M. sinensis. 3 butterfly species, i.e., Eurema hecabe, Pseudozizeeria maha and Chilades pandava were observed in grasslands.

8.3.2.27 No species of conservation importance was recorded in grasslands within the assessment area during the surveys.

Shrubby Grassland

8.3.2.28 Shrubby grasslands are rural lands covered by mixture of shrub and grass species, which each of them occupies at least 1/3 of the coverage.

8.3.2.29 This habitat type is connected to the hillside grasslands close to the Kai Kung Leng hiking trail and occupies approximately 17.81 ha of the assessment area. Among the 22 vegetation species recorded within this habitat type, the most dominant are D. pedata, Miscanthus floridulus, and M. sinensis. A total of nine butterfly and four avifauna species were recorded within habitat type. Approximately 13.80 ha of shrubby grassland identified is located within Lam Tsuen Country Park, and is dominated by the fern D. pedata.

8.3.2.30 One flora species of conservation importance. i.e., Gnetum luofuense, and one avifauna species Stachyridopsis ruficeps, which is considered as Local Concern (LC) by Fellowes et. al. (2002), was recorded in shrubby grasslands within the assessment area during the surveys.

Shrubland

8.3.2.31 Shrublands are rural lands mainly covered by shrub species.

8.3.2.32 This habitat type also appears as large patches of vegetation which occupies around 15.74 ha of the assessment area. A total of 38 vegetation species were recorded within this habitat type. Moreover, 4 species of avifauna and 3 species of butterfly were observed in shrubland during the surveys. Pycnonotus jocosus was the most abundant avifauna while Abisara echerius was the most abundant butterfly recorded.

8.3.2.33 Majority of the identified shrubland in the assessment area (11.82 ha) are within Lam Tsuen Country Park and are adjoined to the contiguous woodland. The vegetation communities in this habitat are abundant with Bambusa spp. Vegetation species such as Bauhinia glauca, Carex cryptostachys, Litsea rotundifolia, Melastoma malabathricum, Psychotria asiatica, Rhus succedanea, Rubus reflexus, and Vigna angularis were also frequently recorded in this habitat type.

Woodland

8.3.2.34 Woodlands are rural lands mainly covered by tree species.

8.3.2.35 This habitat type occupies majority of the assessment area which covers about 187.82 ha and are situated on hilly terrains of NTM to Long Ha. The large contiguous woodland noted in NTM is dominated by native tree species, e.g., Cratoxylum cochinchinense with the presence of Macaranga tanarius var. tomentosa, while P. asiatica is the dominant species in the understory. Some exotic trees such as Acacia mangium, Casuarina equisetifolia and Lophostemon confertus were also recorded. Other vegetation species such as Acronychia pedunculata, Ardisia crenata, Ligustrum sinense, Schefflera heptaphylla, Litsea rotundifolia and Zanthoxylum avicennae are also commonly recorded in this habitat type within the assessment area. Several fauna species were also recorded in woodlands during the surveys, i.e. 17 species of butterfly, 6 dragonfly, 3 reptiles, 10 amphibians, 3 mammals and 28 avifauna species. Among the recorded fauna, D. pasithoe is the most common butterfly, Pantala flavescens for dragonfly, Duttaphrynus melanostictus for amphibian, H. bowringii for reptiles, and P. jocosus for avifauna. A total of 12 species (4 vegetation, 2 herpetofauna, 4 avifauna, and 2 mammals) of conservation importance was recorded in woodlands within the assessment area during the surveys.

8.3.2.36 The Project Site also covers 2.03 ha of woodland from NTM WTW to Long Ha and within the proposed modification of Chamber G. The woodland stretch along fringes of Ching Yau Road is dominated with Leucaena leucocephala. Tree species such as Acacia confusa and Leucaena leucocephala were also observed. Along this area, 10 herpetofauna, 12 avifauna, 8 butterfly species were observed during the surveys. D. melanostictus was the abundant herpetofauna species, Orthotomus sutorius for avifauna, E. hecabe for butterflies. Feeding signs of Sus scrofa were also noted during the surveys.

8.3.2.37 This habitat type covers 73.06 ha of the Lam Tsuen Country Park and is dominated with vegetation species such as C. cochinchinense and P. asiatica.

Plantation

8.3.2.38 Plantations within the assessment area composed of rural lands mainly covered by woody plants and the top canopy is dominated by manually planted species in an organised and systematic way and urban lands undergone artificial greening for various purposes (e.g. golf area courses, urban parks, and vegetation on the roadside).

8.3.2.39 Plantation covers about 26.75 ha of the assessment area and includes landscape plantation, landslip mitigations, and orchards. This habitat type is generally along road verges and are abundant with Bambusa spp., A. confusa, Bauhinia x blakeana, L. leucocephala, Macaranga tanarius var. tomentosa, and Melaleuca cajuputi subsp. cumingiana and Dimocarpus longan. Shrubs. i.e., Bridelia tomentosa, Ixora chinensis, Calliandra haematocephala, and Schefflera arboricola, which are characteristics of landscape treatment were also commonly observed in this habitat type. In terms of fauna, a total of 20 avifauna species were recorded with Passer montanus, and Gracupica nigricollis as the most commonly observed; and 5 butterfly species with P. canidia as the most abundant species. A total of one flora (A. sinensis) and 3 avifauna species of conservation importance was recorded in plantation within the assessment area during the surveys.

8.3.2.40 A portion of plantation (0.55 ha) habitat is also covered within the Project on boundary of NTM WTW. A total of 12 avifauna species and 2 butterfly species were recorded in these areas. The avifauna species, P. jocosus and Zosterpos simplex were the abundant avifauna species in this area. Meanwhile for butterflies, D. pasithoe was abundant.

8.3.2.41 A portion (0.28 ha) of the stretch of planted Lophostemon confertus is covered within Lam Tsuen Country Park. The avifauna species of conservation importance Centropus sinensis was recorded in this area.

8.3.2.42 Developed Area

8.3.2.43 Developed areas are lands occupied by urban, other highly modified habitats, or industrial storage/containers.

8.3.2.44 This habitat type covers about 58.38 ha of the assessment area. Developed areas within the assessment area include roads (i.e., Ching Yau Road, Chuk Yau Road, Wang Ping Shang South Road, San Tam Road and San Tin Highway), rural residential in the NTM village and Long Ha, and facilities such as the NTM WTW and NTM FWPSR, etc. Several fauna species were recorded within this habitat type. Most commonly observed fauna are the domesticated mammals Felis catus and Canis lupus familiaris; common urban bird which can thrive in disturbed areas, i.e. Gracupica nigricollis, Acridotheres cristatellus, P. montanus, P. jocosus and Spilopelia chinensis; the butterflies D. pasithoe and P. canidia; and the dragonfly P. flavescens. Some vegetation species were also observed within this habitat type, particularly planted as ornamental plants in residential areas Duranta erecta, Ficus macrocarpa, and W. trilobata. Only 2 avifauna species of conservation importance, i.e., Corvus torquatus and Callosciurus erythraeus was recorded in developed areas within the assessment area during the surveys.

8.3.2.45 Approximately 0.22 ha of this habitat is within the Project Site which is mainly limited to the section of the proposed freshwater trunk main along Ching Yau Road close to NTM WTW. A total of 30 species were recorded in this habitat type within the Project Site (18 avifauna, 10 butterfly and 2 non-volant mammals). None of the observed species however are of conservation importance.

8.3.3 Mammals

Literature Review

8.3.3.1 According to the findings provided by AFCD, a number of mammal species of conservation concern, namely Small-toothed Ferret Badger, Masked Palm Civet, Leopard Cat, East Asian Porcupine and Small Indian Civet, were detected in the hillside woodlands within Lam Tsuen Country Park and adjacent to the proposed fresh water main to the east of NTM FWPSR.

Survey Findings

8.3.3.2 A total of 7 species of mammals were recorded within the assessment area, commonly in developed areas and woodlands, during the surveys.

8.3.3.3 Some mammal species were recorded based on the signs they left or made, e.g. rooting signs, feeding signs, tracks, scats, etc. Trail cameras were also deployed but no footages of these elusive groups were captured.

8.3.3.4 Of the 7 species recorded, 4 species are listed as species of conservation importance, i.e., Cynopterus sphinx, Callosciurus erythraeus, Muntiacus vaginalis, and Pipistrellus abramus. These species of conservation importance were commonly recorded outside the Project boundary.

8.3.3.5 A complete list of mammal species recorded within the assessment area is attached in Appendix 8.4.

8.3.4 Avifauna

Literature Review

8.3.4.1 Bird community within the assessment area is comprised mostly of open country species and waterbirds given the dominant habitat types present. A total of 7 bird species of conservation importance were reported to occur in the assessment area. These are presented in Table 8.3.

Table 8.3 – Bird species of conservation importance recorded in previous studies

Species	Location and Habitat Recorded
Black-crowned Night Heron	Pok Wai (Pond) ^[2]
Chinese Pond Heron	Pok Wai (Pond)^[2]
Grey Heron	Ngau Tam Mei (Secondary Woodland) ^[1]; Pok Wai (Pond) ^[2]
Purple Heron	Pok Wai (Pond) ^[2]
Little Egret	Pok Wai (Pond) ^[2]
Little Grebe	Pok Wai (Pond) ^[2]
Black Kite	Pok Wai (Pond) ^[2]
Source: [1] AECOM 2009. EIA Report for Hong Kong Section of Guangzhou - Shenzhen - Hong Kong Express Rail Link (AEIAR-143/2009) [2] Ramboll 2016. EIA Report for Proposed Low-rise and Low-density Residential Development at Various Lots and their Adjoining Government Land in D.D. 104, East of Kam Pok Road, Mai Po, Yuen Long. N.T. (AEIAR-205/2017)

Survey Findings

8.3.4.2 A total of 41 avifauna species was recorded within the assessment area during the surveys. A total of 7 avifauna species were listed as species of conservation importance; these include Centropus sinensis, Corvus torquatus, Spilornis cheela, Dicrurus leucophaeus, Milvus migrans, Stachyridopsis ruficeps, and Sturnia sinensis. Avifauna communities were observed in various habitat types but were commonly recorded outside the Project Site in woodlands, developed areas, and modified watercourses.

8.3.4.3 The complete list of avifauna species recorded within the assessment area is attached in Appendix 8.4.

8.3.5 Herpetofauna

Literature Review

8.3.5.1 The herpetofauna community in the assessment area is mostly dominated by common and widespread species typically found in lowland habitats of Hong Kong. Nevertheless, 3 species of conservation importance have been recorded.

8.3.5.2 Ramboll (2016) recorded King Cobra in grassland/shrubland habitat in Pok Wai.

Survey Findings

8.3.5.3 A total of 10 amphibian species were recorded within the assessment area during the surveys. These individuals were generally observed in modified watercourses (ditches) within or near the Project Site. Among these amphibian species identified, only 1 species of conservation importance, Kalophrynus interlineatus, was recorded.

8.3.5.4 A total of 7 reptile species were recorded, generally in modified watercourses and woodlands, during the surveys. Among these reptile species identified, 2 species of conservation importance, i.e., Lycodon capucinus and Gekko gecko, were recorded.

8.3.5.5 A complete list of herpetofauna species recorded within the assessment is attached in Appendix 8.4.

8.3.6 Butterflies

Literature Review

8.3.6.1 The butterfly community in the assessment area is mostly dominated by common and widespread species typically found in lowland habitats of Hong Kong. One species of conservation importance was previously recorded from the assessment area, namely Common Dart, which was recorded from plantation habitat in Ngau Tam Mei (AECOM 2009).

Survey Findings

8.3.6.2 A total of 26 butterfly species were recorded within the assessment area during the surveys. Butterflies were observed in various habitats but were commonly sighted in woodlands and developed areas outside the Project boundary.

8.3.6.3 Majority of these butterflies are common to very common in Hong Kong. No species of conservation importance was recorded. The complete list of butterfly species recorded within the assessment area is attached in Appendix 8.4.

8.3.7 Odonates

Literature Review

8.3.7.1 Diversity of odonates is moderate within the assessment area due to presence of various wetland habitats. However, the community is comprised of common and widespread species, with no species of conservation importance recorded.

Survey Findings

8.3.7.2 A total of 17 odonate species were recorded within the assessment area during the surveys. Odonates were only observed outside the Project boundary, commonly along the riparian areas of artificial ponds and modified watercourses. No odonate of species of conservation importance was recorded. The complete list of odonate species recorded within the assessment area is attached in Appendix 8.4.

8.3.8 Freshwater Community

Literature Review

8.3.8.1 The freshwater fauna community in the assessment area is dominated by common and widespread species typically found in lowland habitats of Hong Kong. No species of conservation importance were reported from the reviewed literatures.

Survey Findings

8.3.8.2 A total of 8 species of aquatic invertebrate and 1 freshwater fish were identified within the assessment area during the surveys. All these species were recorded in various types of modified watercourses outside the Project boundary.

8.3.8.3 2 species of conservation importance, i.e., Cryptopotamon anacoluthon and Caridina serrata, were recorded.

8.3.8.4 A complete list of freshwater fish and aquatic invertebrate species recorded, and their relative abundance is attached in Appendix 8.4.

8.4 Evaluation of Habitats and Species

8.4.1 Habitats

8.4.1.1 In the following section the ecological value of the habitats identified within the assessment area is evaluated in accordance with the criteria stipulated in Annex 8 of the EIAO-TM. Tables 8.4 to 8.12 evaluates the habitats.

Table 8.4 – Evaluation of natural watercourses

Criteria	Perennial and Seasonal Streams
Naturalness	Generally located on hillslopes that have not undergone modification with nil to minimal disturbance
Size	~10.62 km
Diversity	Very Low
Rarity	Common habitat in Hong Kong; over 2,500 km of natural streams and rivers in Hong Kong, mostly located in hillsides remote from developed areas. No species of conservation importance recorded from this habitat.
Re-creatability	Difficult to recreate
Fragmentation	Not considered fragmented
Ecological Linkage	Functionally and hydrologically linked with a modified watercourse where species of conservation importance (Cryptopotamon anacoluthon and Caridina serrata) were observed.
Potential Value	Moderate potential value due to less disturbance
Nursery/Breeding Ground	Potential nursey ground for aquatic fauna
Age	Old
Abundance/Richness of wildlife	Low
Overall Value	Low to Moderate

Table 8.5 – Evaluation of artificial ponds

Criteria	Active Ponds	Abandoned Ponds
Naturalness	Man-made artificial water bodies constructed for aquaculture and conservation purposes
Size	~6.78 ha	~0.37 ha
Diversity	High for dragonflies; low for flora and other wildlife	Very low
Rarity	Common in the northwest New Territories albeit declining; no species of conservation importance recorded during the survey
Re-creatability	Could be recreated under suitable hydrological conditions
Fragmentation	Some fragmented and isolated
Ecological Linkage	Linked to some water channels
Potential Value	High potential value if well managed	Low
Nursery/Breeding Ground	Nursery for fishes	No significant record
Age	More than 10 years based on satellite images
Abundance/Richness of wildlife	Low to Moderate	Very Low
Overall Value	Low to Moderate	Low

Table 8.6 – Evaluation of modified watercourses

Criteria	Modified Watercourses
Naturalness	Man-made and modified with human disturbance
Size	~6.83 km
Diversity	Moderate to high diversity for avifauna and other aquatic fauna; Low for flora and other wildlife.
Rarity	Common in Hong Kong; 2 herpetofauna, and 2 aquatic invertebrate species of conservation importance were recorded during the survey.
Re-creatability	Easily recreated
Fragmentation	Highly fragmented
Ecological Linkage	Functionally and hydrologically linked with nearby water channels and wetland habitats such as ponds; linkage to Deep Bay Area
Potential Value	Low potential value due to the surrounding disturbance
Nursery/Breeding Ground	Potential nursery ground for fish and dragonfly species
Age	Old; more than 20 years based on satellite images
Abundance/Richness of wildlife	Moderate to high
Overall Value	Moderate

Table 8.7 – Evaluation of grassland

Criteria	Grassland
Naturalness	Semi-natural for lowland grassland nearby village areas
Size	~7.53 ha
Diversity	Low for both flora and fauna; low structural complexity
Rarity	Common habitat in Hong Kong; no species of conservation importance observed in the habitat
Re-creatability	Easily modified by hillside fires
Fragmentation	Fragmented
Ecological Linkage	Connected to woodland areas within and adjacent to Lam Tsuen Country Park
Potential Value	Low
Nursery/Breeding Ground	No significant record
Age	N/A
Abundance/Richness of wildlife	Low
Overall Value	Low to Moderate

Table 8.8 – Evaluation of shrubby grassland

Criteria	Shrubby Grassland
Naturalness	Semi-natural
Size	~17.81 ha
Diversity	Low for both flora and fauna; low structural complexity
Rarity	Common habitat in Hong Kong; one vegetation species and one avifauna species of conservation importance observed in this habitat
Re-creatability	Readily recreated
Fragmentation	Fragmented
Ecological Linkage	Connected to woodland areas within and adjacent to Lam Tsuen Country Park
Potential Value	Low
Nursery/Breeding Ground	No significant record
Age	N/A
Abundance/Richness of wildlife	Low
Overall Value	Low to Moderate

Table 8.9 - Evaluation of shrubland

Criteria	Shrubland
Naturalness	Semi-natural; early stage of natural vegetation succession
Size	~15.74 ha
Diversity	Low for both flora and fauna; low structural complexity
Rarity	Common habitat in Hong Kong; no species of conservation importance recorded
Re-creatability	Readily recreated
Fragmentation	Fragmented
Ecological Linkage	Connected to woodland areas within and adjacent to Lam Tsuen Country Park
Potential Value	Low
Nursery/Breeding Ground	No significant record
Age	N/A
Abundance/Richness of wildlife	Low
Overall Value	Low to Moderate

Table 8.10 – Evaluation of woodland

Criteria	Woodland
Naturalness	Semi-natural
Size	~187.82 ha
Diversity	Moderate for both flora and fauna; low structural complexity; 4 vegetation, 2 herpetofauna, 4 avifauna, and 2 mammals of conservation importance observed in this habitat during the surveys.
Rarity	Common habitat in Hong Kong
Re-creatability	Can be recreated by compensatory planting and transplantation
Fragmentation	Little fragmentation
Ecological Linkage	Some ecological linkage with other habitats
Potential Value	Low to moderate
Nursery/Breeding Ground	Potential breeding/nursery ground but no significant record
Age	More than 20 years based on satellite images
Abundance/Richness of wildlife	Low to moderate
Overall Value	Moderate for hillside woodland within and adjoining Lam Tsuen Country Park; Low to Moderate for other woodland located close to developed areas and along roadsides

Table 8.11 – Evaluation of plantation

Criteria	Plantation
Naturalness	Man-made; highly disturbed as adjacent to developed areas
Size	~26.75 ha
Diversity	Moderate both flora and fauna; low structural complexity
Rarity	Common habitat in Hong Kong; one vegetation species and 3 avifauna species of conservation importance observed in this habitat
Re-creatability	Can be recreated by compensatory planting and transplantation
Fragmentation	Heavily fragmented
Ecological Linkage	Low ecological linkage with other habitats as the surrounding areas are developed and disturbed
Potential Value	Low to moderate
Nursery/Breeding Ground	Potential breeding/nursery ground but no significant record
Age	More than 10 years based on satellite images
Abundance/Richness of wildlife	Low
Overall Value	Low

Table 8.12 – Evaluation of developed area

Criteria	Developed Area
Naturalness	Entirely man-made habitat and highly disturbed
Size	~58.38 ha
Diversity	Low for both flora and fauna; low structural complexity
Rarity	Common habitat in Hong Kong; only 1 avifauna and 1 mammal species of conservation importance recorded
Re-creatability	Readily recreated
Fragmentation	Heavily fragmented
Ecological Linkage	Low ecological linkage with other habitats
Potential Value	Low
Nursery/Breeding Ground	No
Age	N/A
Abundance/Richness of wildlife	Low
Overall Value	Low

8.4.2 Species

8.4.2.1 The evaluation of the species of conservation importance recorded within the assessment area, according to the EIAO-TM, is given in Tables 8.13 and 8.14 below. The location of species of conservation importance is shown in Figure 8.4 and the representative photos of species of conservation importance is shown in Appendix 8.5.

Table 8.13 – Evaluation of floral species of conservation importance

Species	Conservation and Protection Status	Distribution	Rarity	Location Recorded
Aquilaria sinensis	RPPHK (NT) ; CRDB (VU)	Common	Native	At the back NTM WTW facility; and adjacent to NTM FWPSR
Cibotium barometz	RPPHK (VU) ; Cap. 586	Common	Native	Hillside adjacent to NTM WTW facility
Camellia euryoides	Near Threated (IUCN)	Very Common	Native	Hillside adjacent and at the back of NTM WTW facility
Gnetum luofuense	Near Threated (IUCN)	Common	Native	Roadside of Ching Yau Road going to NTM WTW facility; Hillside adjacent and at the back of NTM WTW facility
Notes: [1] Origin and Status in Hong Kong were retrieved from https://bih.gov.hk/en/species-database/index.html (2022) [2] Conservation Status were based on the following: a. Cap. 96 Forests and Countryside Ordinance, including the associated Chapter 96A Forestry Regulation b. Cap. 586 Protection of Endangered Species of Animal and Plants Ordinance c. Xing et al. (2000) d. Rare and Precious Plants of Hong Kong (RPPHK) (AFCD 2003, Online Version) e. IUCN 2022 f. China Red Data Book (CRDB) was retrieved from https://bih.gov.hk/en/species-database/index.html (2022) [3] In this list, plant species is considered as species of conservation importance, if it is scheduled under Cap. 96A, protected under Cap. 586, documented as rare/protected species in AFCD (2003), or has conservation status under IUCN Red List of Threatened Species and China Red Data Book; and its population is native and not cultivated in Hong Kong.

Table 8.14 – Evaluation of faunal species of conservation importance

Species	Conservation & Protection Status	Distribution	Rarity	Location Recorded
Centropus sinensis	CSMPS(II)	Widely distributed in Hong Kong.	Common resident	Hillside adjacent and at the back of NTM WTW facility
Corvus torquatus	LC; RLCV (NT); IUCN (VU)	Found in Inner Deep Bay area, Nam Chung, Kei Ling Ha, Tai Mei Tuk, Pok Fu Lam, Chek lap Kok, Shuen Wan, Lam Tsuen.	Locally common resident	Woodland near Wang Ping Shan South Road
Spilornis cheela	(LC); RLCV(NT); CITES(II);	Widely distributed in shrublands on hillsides throughout Hong Kong.	Common resident	In flight within the assessment area
Dicrurus leucophaeus	LC	Found in Shing Mun, Tai Po Kau	Uncommon winter visitor	Woodland near Wang Ping Shan South Road
Milvus migrans	Cap. 589 ; (RC); CSMPS(II)	Widely distributed in Hong Kong.	Common resident and winter visitor	Hillside at the back of NTM WTW facility
Stachyridopsis ruficeps	LC	Found in Shing Mun, Tai Po Kau, Tai Mek Tuk, Ng Tung Chai, Fo Tan, Tai Mo Shan, The Peak, Kadoorie Agricultural Research Centre.	Common resident	Hillside adjacent to the NTM WTW facility
Sturnia sinensis	(LC)	Found in Kam Tin, Deep Bay area, Po Toi Island, Long Valley, Victoria Park, Ho Chung, Ma Tso Lung, Mui Wo, Lam Tsuen Valley.	Locally common passage migrant and uncommon winter visitor	Woodland near Wang Ping Shan South Road
Kalophrynus interlineatus	RLCV(NT)	Widely distributed from low to moderate altitudes in northern and central New Territories.	-	Along Ching Yau Road near NTM Ventilation building
Gekko gecko	Cap. 586; RLCV(CE); CITES (II); RC	Distributed on Lamma Island, Lantau Island, Hong Kong Island, Lion Rock Country Park, Ma On Shan Country Park and Pat Sin Leng Country Park.	-	Along Ching Yau Road near NTM Ventilation building; Hillside adjacent to the NTM WTW facility
Lycodon capucinus	RLCV (NT)	Widely distributed at low elevations throughout Hong Kong Island, Lantau Island and Lamma Island	-	Along Ching Yau Road near NTM Ventilation building; NTM FWPSR
Cynopterus sphinx	RLCV (NT); Cap. 170	Very widely distributed in urban and countryside areas throughout Hong Kong	Common	Along Ching Yau Road near NTM Ventilation building
Callosciurus erythraeus	LC(RLCB); Cap.170	Fairly widely distributed, with the styani subspecies found in the New Territories (e.g. Tai Lam, Shing Mun and Tai Po Kau), and the thai subspecies found on the Hong Kong Island (e.g. Tai Tam and Pok Fu Lam).	Very Common	Recorded in developed area along Wang Ping Shan South Road
Hystrix brachyura	PGC; Cap.170	Very widely distributed in countryside areas throughout Hong Kong, except for Lantau Island.	Very Common	Woodlands within Lam Tsuen Country Park and adjacent to the proposed fresh water main to the east of NTM FWPSR (recorded by AFCD)
Melogale moschata	RLCV(NT); Cap.170	Widely distributed in countryside areas throughout Hong Kong.	Common	Woodlands within Lam Tsuen Country Park and adjacent to the proposed fresh water main to the east of NTM FWPSR (recorded by AFCD)
Muntiacus vaginalis	RLCV (NT)	Very widely distributed in countryside areas throughout Hong Kong.	Abundant	Hillside adjacent to the NTM WTW facility
Paguma larvata	PRC; RLCV(NT); CITES(III); Cap.170; Cap.586	Widely distributed in countryside areas throughout Hong Kong, except for Lantau Island and northwestern New Territories.	Uncommon	Woodlands within Lam Tsuen Country Park and adjacent to the proposed fresh water main to the east of NTM FWPSR (recorded by AFCD)
Pipistrellus abramus	Cap. 170	Widely distributed throughout Hong Kong.	Common	Long Ha
Prionailurus bengalensis	RLCV(VU); CITES(II); Cap.170; Cap.586	Widely distributed in countryside areas throughout Hong Kong, except for Lantau Island.	Uncommon	Woodlands within Lam Tsuen Country Park and adjacent to the proposed fresh water main to the east of NTM FWPSR (recorded by AFCD)
Viverricula indica	RLCV(VU); CSMPS(II); CITES(III); Cap.170; Cap.586	Very widely distributed in countryside areas throughout Hong Kong, except for Lantau Island.	Very Common	Woodlands within Lam Tsuen Country Park and adjacent to the proposed fresh water main to the east of NTM FWPSR (recorded by AFCD)
Cryptopotamon anacoluthon	IUCN(VU)	Wu Kwai Sha, Kwun Yum Shan and Tai Po Kau Forest Reserve in New Territories and the Peak on Hong Kong Island	Fairly common and widespread in local unpolluted streams	Modified watercourse in Freshwater ecology sampling station FE10
Caridina serrata	IUCN(NT)	Hong Kong Island	Endemic	Modified watercourse in Freshwater ecology sampling station FE10
Notes: [1] Conservation and Protection Status refers to: a. Fellowes et al. 2002: LC (Local Concern); PRC (Potential Regional Concern); RC (Regional Concern); PGC (Potential Global Concern); GC (Global Concern). Letters in parentheses indicate that the assessment is on the basis of restrictedness in breeding and/or roosting sites rather than in general occurrence. b. Red List of China’s Vertebrates (RLCV), Jiang et al. 2016: NT (Near Threatened); VU (Vulnerable); EN (Endangered); CR (Critically Endangered) c. IUCN 2022: NT (Near Threatened); VU (Vulnerable); EN (Endangered); CR (Critically Endangered) d. China State Major Protection Status (CSMPS): II = Class II Protected Species in China e. CITES 2021: CITES(II) = Listed in CITES Appendix II; CITES(III) = Listed in CITES Appendix III. f. Cap. 170: Wild Animals Protection Ordinance. All wild birds in Hong Kong are protected under Cap. 170. g. Cap. 586 = Protection of Endangered Species of Animals and Plants Ordinance. [2] No direct observations. Detected by bat detector.

8.5 Impact Identification and Evaluation

8.5.1 Construction Phase

Direct Impact of Habitat Loss

8.5.1.1 Areas of habitats covered within the works boundary are presented in Table 8.15.

Table 8.15 – Habitats within the Project Boundary

Habitat Type	Area (ha)
	Freshwater Trunk Main between Ching Yau Road and San Tam Road	Freshwater Trunk Main between NTM WTW and NTM FWPSR	Proposed Modification of Chamber G
Natural Watercourse	-	0.003 (Low to Moderate Value)	-
Woodland	0.09 (Low to Moderate Value)	0.06 (Low to Moderate Value)	1.88 (Moderate Value)
Plantation	-	0.03 (Low Value)	0.52 (Low Value)
Developed Area	-	0.22 (Low Value)	-
Remark: [1] Habitats recorded within the project boundary of modification of Chamber G are included in the calculation.

8.5.1.2 Under the current project layout (see Figure 1.1), the actual habitat loss will be restricted to the proposed fresh water trunk mains. The proposed modification works at Chamber G will only involve underground works. No surface construction nor aboveground works will be required within the Country Park. Furthermore, no GI works and slope works will be conducted within Lam Tsuen Country Park.

8.5.1.3 For the fresh water trunk main laying works between the NTM WTW and NTM FWPSR, although the section would encroach onto CA, the proposed fresh water trunk mains will be constructed along the existing access road within urban or developed areas, and will not result in any significant habitat loss (although a minor loss of 0.06ha of woodland would occur). No direct loss of watercourses is expected to occur for the construction of this section, as there will not be any in-stream works.

8.5.1.4 A short section of the fresh water trunk mains between Ching Yau Road and San Tam Road would also encroach into CA, the required works would be located within existing woodland habitat. The associated construction works would be minor excavation, mainlaying and backfilling. A minor loss of 0.09ha of woodland is anticipated but is not considered significant.

Table 8.16 – Evaluation of direct impacts to habitats in the absence of mitigation measures

Criteria	Woodland	Plantation	Developed Area
Habitat Quality	Low to Moderate	Low	Low
Species	Only common and widespread species involved. No species of conservation importance were recorded from these habitats to be directly impacted.
Size/Abundance	Small size (0.15ha); Low to moderate abundance	Small size (0.03ha); Low abundance	Small size (0.22ha); Low abundance
Duration	Permanent (as direct habitat loss)
Reversibility	Irreversible
Magnitude	High magnitude (as direct habitat loss)
Significance of Impact	Low given the small size of habitat to be affected	Very Low given the small size of habitat to be affected and low ecological value	Very Low for developed area of low ecological value

Direct Impact to Species of Conservation Importance

8.5.1.5 No direct impacts to species of conservation importance are expected as none of these species were recorded within the proposed works areas.

Indirect Impacts to Habitats and Species of Conservation Importance

8.5.1.6 Disturbance to habitats and associated fauna adjacent to the Project could result from construction activities such as dust generation, waste dumping, glare, construction noise and increased traffic and human activities.

8.5.1.7 Dust generated due to construction works, if not effectively controlled, could affect the health of adjacent vegetation. Excessive dust covering leaves can lead to reduction in their photosynthetic rates, abrasion and blocking of stomata. Improper dumping of construction materials and waste within and/or near to the works areas may result in environmental degradation of the surrounding habitat, which is more sensitive for the flora species of conservation importance. Considering that works will be of small scale and conducted in phases, the relevant impact is considered to be minor.

8.5.1.8 Potential disturbance by construction noise and glare from lights associated with works sites and increased human activities may cause wildlife to avoid using areas adjacent to the works area, and thereby reduce wildlife density in the area. However, given that the construction works will be carried out mostly on developed areas, without mitigation, such disturbance to the wildlife nearby, of which most are highly mobile, would be of low significance.

8.5.1.9 The proposed modification works at Chamber G may potentially cause indirect impacts to the habitats and the associated wildlife nearby due to groundborne noise and vibration. Nevertheless, the potential impact is considered to be of low level in the absence of mitigation measures, as the stratum under the natural ground surface consists of colluvium, saprolite, corestone and rock. Furthermore, construction of tunnels would be conducted using the mined excavation with drill and break method, where vibration would be minimised as no blasting is required.

8.5.1.10 Disturbance impacts to aquatic and riparian zone fauna include water pollution from uncontrolled site runoff and accidental discharge or spillage of waste water, chemical, lubricants into watercourses and the ponds. Siltation may also occur as suspended particles would be carried into the potentially affected watercourses via surface runoff. Given the sensitivity of the areas that would be potentially affected, the potential impact is considered to be of low to moderate level in the absence of mitigation measures.

8.5.1.11 As the fresh water trunk main laying works will be largely confined to developed areas, no significant impacts to hydrology or hydrodynamics properties are anticipated. With reference to Section 5, given that the key potential water quality impacts are mainly associated with the proposed fresh water trunk mains laying works, the natural habitats in Lam Tsuen Country Park, which is located uphill of the proposed works, would not be significantly affected.

8.5.1.12 The proposed modification works at Chamber G may accidentally result in groundwater drawdown or infiltration from tunnelling and dewatering of surface waters during the construction phase. Nonetheless, the underground modification of Chamber G in Lam Tsuen Country Park is located away from existing watercourses and other waterbodies, as well as any species of conservation importance. With the implementation of the groundwater control measures proposed in Section 5.7.6, the potential impact on Lam Tsuen Country Park resulting from the modification works at Chamber G is considered to be of low level.

8.5.1.13 The evaluations of indirect construction phase impacts are given in Tables 8.17 to 8.20.

Table 8.17 – Evaluation of indirect construction phase impacts to watercourses in the absence of mitigation measures

Criteria	Natural Watercourses	Modified Watercourses
Habitat Quality	Low to moderate	Moderate
Species	Species diversity is low. No species of conservation importance recorded from this habitat.	Moderate to high diversity. 2 herpetofauna, and 2 aquatic invertebrate species of conservation importance were recorded.
Size/Abundance	~10.62 km. Low wildlife abundance.	~6.83 km. Moderate to high abundance.
Duration	Temporary only
Reversibility	Construction phase indirect impacts are reversible.
Magnitude	Moderate due to potential water pollution
Significance of Impact	Low	Low to Moderate

Table 8.18 – Evaluation of indirect construction phase impacts to fishponds in the absence of mitigation measures

Criteria	Active Ponds	Abandoned Ponds
Habitat Quality	Low to moderate	Low
Species	Species diversity is high for dragonflies; low for flora and other wildlife. No species of conservation importance recorded from this habitat.	Species diversity is very low. No species of conservation importance recorded from this habitat.
Size/Abundance	~6.78 ha. Abundance is low to moderate.	~0.37 ha. Very low abundance.
Duration	Temporary only
Reversibility	Construction phase indirect impacts are reversible.
Magnitude	Moderate due to potential water pollution
Significance of Impact	Low to Moderate	Low

Table 8.19 – Evaluation of indirect construction phase impacts to grassland, shrubby grassland and shrubland in the absence of mitigation measures

Criteria	Grasslands	Shrubby Grasslands	Shrublands
Habitat Quality	Low to moderate	Low to moderate	Low to moderate
Species	Species diversity is low. No species of conservation importance recorded from this habitat.	Species diversity is low. 1 vegetation species and 1 avifauna species of conservation importance recorded.	Species diversity is low. No species of conservation importance recorded from this habitat.
Size/Abundance	~7.53 ha. Abundance of wildlife is low.	~17.81 ha. Abundance of wildlife is low.	~15.74 ha. Abundance of wildlife is low.
Duration	Temporary only
Reversibility	Construction phase indirect impacts are reversible.
Magnitude	Low
Significance of Impact	Low	Low	Low

Table 8.20 – Evaluation of indirect construction phase impacts to plantation, woodland and developed area in the absence of mitigation measures

Criteria	Plantations	Woodlands	Developed Areas
Habitat Quality	Low	Moderate for hillside woodlands within and adjoining Lam Tsuen Country Park; Low to Moderate for others	Low
Species	Moderate diversity. 1 vegetation and 3 avifauna species of conservation importance recorded.	Moderate diversity. 4 vegetation, 2 herpetofauna, 4 avifauna, and 2 mammals of conservation importance observed in the surveys.	Species diversity is low. 1 avifauna and 1 mammal species of conservation importance recorded
Size/Abundance	~26.75 ha. Abundance of wildlife is low.	~187.82 ha. Abundance of wildlife is low to moderate.	~58.38 ha. Abundance of wildlife is low.
Duration	Temporary only
Reversibility	Construction phase indirect impacts are reversible.
Magnitude	Low
Significance of Impact	Low	Low	Very Low

8.5.2 Operational Phase

Direct Impacts

8.5.2.1 No further direct impacts to habitats and species are anticipated during the operational phase of the Project.

Indirect Impacts

8.5.2.2 With reference to the air, noise and water quality impact assessment chapters, no significant indirect impacts during the operation phase of the Project have been identified. Operational phase indirect impacts are considered to be negligible.

Cumulative Impacts

8.5.2.3 A list of concurrent projects is provided below in Table 8.18. Considering that the aboveground works will be located largely within developed areas, and that no major projects are located within 500m of the proposed works, significant cumulative impacts are not anticipated.

8.5.2.4 In terms of the concurrent project, NTM WTW Extension, the proposed works (including construction and upgrading of buildings and facilities) within NTM WTW will be restricted to existing developed area or plantation habitat. The minor loss of plantation and developed area, which are both considered to be of low ecological value, is not considered to be significant. A section of modified watercourse is located within the boundary of NTM WTW, it will not be directly affected as no works are proposed in this habitat. The extension of NTM FWPSR will be restricted to the existing developed area and will not encroach into the adjacent woodland habitat. Therefore, only a minor loss of 0.15 ha of woodland is anticipated under the Project. Furthermore, the associated loss of developed area is considered to be insignificant. Significant cumulative impacts are therefore not anticipated.

Table 8.18 – List of Concurrent projects

Concurrent Projects	Programme
	Start	Complete
Site Formation and Infrastructure Works for Public Housing Developments at Sha Po, Shap Pat Heung and Tai Kei Leng, Yuen Long	2026	2031
Northern Link	2025	2034
NTM WTW Extension (under PER)	2024	2030

8.6 Avoidance / Minimisation / Mitigation Measures

8.6.1 Avoidance

8.6.1.1 The fresh water trunk main laying works will be confined largely to developed areas to avoid direct impacts to natural or semi-natural habitats, as well as any recognised sites of conservation importance. Aboveground works in Lam Tsuen Country Park will also be completely avoided. Although small sections of the fresh water trunk mains from NTM WTW to NTM FWPSR and from Ching Yau Road to San Tam Road would encroach into CA, the required works would be located along the existing access roads/ slope adjacent to existing access road. The associated construction works would be minor excavation, mainlaying and backfilling, therefore, no significant ecological impacts to the CA is anticipated.

8.6.1.2 The proposed works have also avoided direct impacts to floral and faunal species of conservation importance.

8.6.2 Minimisation

8.6.2.1 To minimise disturbances to the nearby habitats and associated wildlife, the mitigation measures proposed in the other sections of this EIA Report should be implemented during the construction phase.

8.6.2.2 Good site practice should be enforced, and effective mitigation measures are required. In particular, the Practice Note for Professional Persons (ProPECC PN 2/23) on Construction Site Drainage provides guidelines for the handling and disposal of construction discharges. It should be followed strictly to control site runoff and wastewater generated during the construction phase. Other mitigation measures during construction phase are listed as follows:

· Erect fences along the boundary of the works area before the start of works to prevent vehicle movements and encroachment of personnel onto adjacent natural habitats. Regularly check the boundaries to ensure that they are not breached;

· Avoid any damage and disturbance, particularly to minimise risk of filling and illegal dumping, to the adjacent habitats during construction;

· Avoid directing lighting from works sites towards adjacent habitats and any other ecologically sensitive areas;

· Prohibit and prevent open fires within the site boundary during construction and provide temporary fire-fighting equipment in work areas to minimise the possibility of hill fires;

· Cover excavated material or stockpiles of construction material with tarpaulin during rain events to prevent the washing of these materials into adjacent watercourses and ponds;

· Cover stockpiles of loose material and carrying out dust suppression spraying on all access roads to mitigate dust generation;

· Provide waste skips to collect general refuse and construction waste, which should be disposed regularly and properly off-site;

· Proper selection of quiet plant aiming to reduce the tonality at NSRs;

· Installation of silencer / acoustic enclosure / acoustic louvre for the exhaust of ventilation system; and

8.6.2.3 To minimise impacts to the groundwater table, groundwater control strategies listed in Section 5.7.6 should be duly followed.

8.7 Residual Impacts

8.7.1.1 With the effective implementation of the recommended mitigation measures, no adverse residual ecological impact is anticipated.

8.8 Environmental Monitoring and Audit (EM&A)

8.8.1 Construction Phase

8.8.1.1 Regular site audit should be conducted to ensure the recommended mitigation measures are properly implemented.

8.8.2 Operational Phase

8.8.2.1 No ecological monitoring and audit is necessary during the operational phase of the Project.

8.9 Conclusion

8.9.1.1 Literature review and a 6-month ecological field survey covering both wet and dry seasons were undertaken to establish the ecological profile of the proposed works areas and assessment area. The proposed works areas are dominated by developed areas with low ecological value.

8.9.1.2 The proposed aboveground works would not encroach into the boundary of Lam Tsuen Country Park, hence no direct impact on wildlife and habitats within the Country Park is anticipated. Although small sections of the fresh water trunk mains from NTM WTW to NTM FWPSR and from Ching Yau Road to San Tam Road would encroach into CA, the required works would be located along the existing access roads/ slope adjacent to existing access road or within water works reserve area. The associated construction works would be minor excavation, mainlaying and backfilling, therefore, no significant ecological impacts to the CA is anticipated.

8.9.1.3 The proposed modification works at Chamber G may potentially cause indirect impacts to the habitats and the associated wildlife nearby due to groundborne noise and vibration. Nevertheless, the potential impact is considered to be of low level in the absence of mitigation measures, as the stratum under the natural ground surface consists of colluvium, saprolite, corestone and rock. Furthermore, construction of tunnels would be conducted using mined excavation with drill and break method, where vibration would be minimised as no blasting is required.

8.9.1.4 The potential construction runoff and other disturbance impacts resulting from the proposed works, including impacts to the groundwater table, may potentially have indirect impact on wildlife and species of conservation interest. Good site practice and control of groundwater infiltration are proposed.

8.9.1.5 Overall, with the effective implementation of the recommended good site practices, no significant adverse residual ecological impacts during construction and operational phases are expected from the Project.

8.10 Reference

AECOM Asia Limited (AECOM). 2009. EIA Report for Hong Kong Section of Guangzhou - Shenzhen - Hong Kong Express Rail Link (EIA-169/2009)

Corlett, R., Xing, F., Ng, S. C., Chau, L., Wong, L. (2000). Hong Kong Vascular Plants: Distribution and Status. Memoirs of the Hong Kong Natural History Society. Hong Kong.

International Union for Conservation of Nature (IUCN). 2022. Accessed at
https://www.iucnredlist.org/.

Kwong, I. H. Y., Wong, F. K. K., Fung, T., Liu, E. K. Y., Lee, R. H., & Ng, T. P. T. 2022. A Multi-Stage Approach Combining Very High-Resolution Satellite Image, GIS Database and Post-Classification Modification Rules for Habitat Mapping in Hong Kong. Remote Sensing, 14(1), 67 at https://doi.org/10.3390/rs14010067.

Qin et al. 2017. Threatened Species List of China's Higher Plants. Biodiversity Science 25:696-744

Ramboll Hong Kong Limited (Ramboll). 2016. EIA Report for Proposed Low-rise and Low-density Residential Development at Various Lots and their Adjoining Government Land in D.D. 104, East of Kam Pok Road, Mai Po, Yuen Long. N.T. (EIA-242/2016)

9 Fisheries Impact

9.1 Legislation, Standards and Guidelines

9.1.1.1 The relevant legislations, standards and guidelines applicable to the present study for the assessment of fisheries impact assessment:

· Environmental Impact Assessment Ordinance (EIAO) (Cap. 499) and the associated Technical Memorandum (EIAO-TM);

· Marine Fish Culture Ordinance (Cap. 353);

· Fisheries Protection Ordinance (Cap. 171); and

· Water Pollution Control Ordinance (WPCO) (Cap. 358).

9.2 Assessment Methodology

9.2.1.1 The assessment area includes areas within 500m from the boundary of the Project and associated works as well as any other areas likely to be impacted by the Project. (see Figure 9.1) The area for fisheries impact includes all fish ponds within the assessment area. Special attention is given to the potential impacts on aquaculture activities and the loss of fish ponds.

9.2.1.2 Literature review and internet search have been conducted to assess the baseline status of culture fisheries and capture fisheries within the assessment area as well as the territory. Literatures, websites and approved EIA reports reviewed include:

· AFCD Annual Reports (1997-2023);

· Proposed Low-rise and Low-density Residential Development at Various Lots and their Adjoining Government Land in D.D. 104, East of Kam Pok Road, Mai Po, Yuen Long. N.T. (AEIAR‑205/2017);

· Hong Kong Section of Guangzhou - Shenzhen - Hong Kong Express Rail Link (AEIAR-143/2009).

9.2.1.3 Status of ponds identified within the assessment area was investigated with reference to latest satellite images and aerial photographs, and supplemented by site visits where necessary. Ponds identified are categorised as follows:

· Active: evidence of commercial aquaculture activities, including commercial fish ponds, fish fry ponds.

· Inactive: no evidence of commercial aquaculture activities, but no major physical constraints to its resumption in the short-term, including ponds with fish present in non-commercial quantities and ponds for casual sport fishing or water sports.

· Abandoned: physical evidence that aquaculture has not taken place for many years (i.e. overgrown) and/or where there are obvious physical constraints to its short-term resumption (i.e. fenced); concreted ornamental ponds and ponds for wetland compensation or wastewater treatment are also included in this category.

9.3 Fisheries Baseline Conditions

9.3.1 Pond Fish Culture

Literature Review

9.3.1.1 Pond fish culture has been practised in the New Territories for a long period of time. Traditionally, only primary freshwater fish and several brackish species, such as Bighead Carp Aristichthys nobilis, Edible Goldfish Carassius auratus, Grass Carp Ctenopharyngodon idellus, Mud Carp Cirrhinus chinensis, Flathead Mullet and Nile Tilapia Oreochromis niloticus, are farmed. However, in recent years, certain high-value marine species such as Giant Grouper Epinephelus lanceolatus, Yellowfin Seabream Acanthopagrus latus and Spotted Scat Scatophagus argus have also been cultured in diluted seawater by fish farms close to the coast (e.g. at Mai Po).

9.3.1.2 In order to help local fish farms to develop, AFCD has introduced new aquaculture species (i.e. Jade Perch Scortum barcoo) to Hong Kong, and also launched the “Accredited Fish Farm Scheme” (AFFS). Under this scheme, products from registered fish farms are “accredited” by AFCD, and can be marketed under the unique brand name of the scheme. The department believes that this scheme can make local aquaculture products “stand out by branding”.

9.3.1.3 Several fish farms have started to culture new species and AFCD has carried out much promotional work; according to the data extracted from AFCD’s website and AFCD’s annual reports, the production of pond fish in Hong Kong has stabilised in recent years.

9.3.1.4 In 2023, the local inland ponds, covering an area of approximately 1,130 ha, produced 1,052 tonnes of freshwater fish amounting to $28 million. About 92% of the farms are engaged in polyculture (Bighead Carp, Grass Carp, Common Carp and Silver Carp in combination with Tilapia or Grey Mullet). The remaining 8% practise monoculture of carnivorous species such as Giant Groupers, Seabreams and Spotted Scat in brackish fish ponds near to the coastline.

9.3.1.5 Majority of the fish fry and fingerlings are imported from the Mainland and Taiwan. Some of the grey mullet fry may also be caught in local coastal waters. Traditionally, fry are stocked in early spring and most fish species reach marketable size in eight to twelve months.

9.3.1.6 Annual pond fish production and fish pond area in Hong Kong as a whole are listed in the Table 9.1.

Table 9.1 – Annual pond fish production and fish pond area

Year	Pond Fish Production (tonne)	Fish Pond Area (ha)	Overall Pond Fish Production Rate (kg/ha/year)
1997	5000	1125	4444
1998	4900	1110	4414
1999	4500	1094	4113
2000	2817	1060	2657
2001	2550	1059	2407
2002	1989	1030	1931
2003	2114	1029	2054
2004	1977	1026	1927
2005	1897	1026	1849
2006	1943	1024	1897
2007	1927	1160	1661
2008	2266	1160	1953
2009	2105	1160	1814
2010	2190	1109	1975
2011	2315	1130	2049
2012	2244	1149	1953
2013	2187	1150	1902
2014	2001	1140	1775
2015	2092	1140	1835
2016	2543	1135	2241
2017	2543	1132	2246
2018	2536	1132	2240
2019	2278	1131	2014
2020	2516	1130	2227
2021	2926	1130	2589
2022	2073	1129	1836
2023	1052	1130	931

Survey Findings

9.3.1.7 The distribution of ponds within the assessment area is presented on Figure 9.1; while the current status of each pond within the 500m assessment area is shown in Figure 9.2.

9.3.1.8 Status of ponds as confirmed by field visits are presented below in Table 9.2. Only a few fishponds were operated in a commercial manner for food fish production. No fishponds were found within the works areas of the Project.

Table 9.2 - Status of ponds within the assessment area

Pond No.	Location	Status	Water Quality	Remarks
NTM-1	Ngau Tam Mei	Active	Good	Aerated fenced ponds which breeds Koi for competition
NTM-2		Active	Good	Aerated fenced ponds which breeds Koi for competition
NTM-3		Active	Good	Breeds Koi for competition
NTM-4		Active	Good	Shallow pond with non-commercial amount of Tilapia
NTM-6		Active	Good	Non-aerated, AFCD supported fish nursery
NTM-7		Active	Good	Aerated ponds which breeds Koi for competition
NTM-8		Active	Good	Aerated fenced ponds which breeds Koi for competition
NTM-9		Active	Good	Aerated ponds which breeds Koi for competition
MYC-1	Man Yuen Chuen	Abandoned	N/A	Dry and overgrown

9.3.1.9 A summary of current status, the nature of operations, and land area of ponds within the 500m assessment area is provided in Table 9.3.

Table 9.3 – Summary of status and area of ponds within Project site and assessment area

Area	Pond Status	No. of Ponds	Nature of Operation	Total Area (ha)
Within Project Site	Active	0	N/A	0
	Inactive	0	N/A	0
	Abandoned	0	N/A	0
Within Assessment Area	Active	6	Koi Fish Farming	6.77
		1	Nursery
		1	For Self Consumption Only
	Abandoned	1	N/A	0.65

9.3.2 Other Forms of Aquaculture

9.3.2.1 No other forms of aquaculture such as marine fish culture or oyster culture were identified within or near the assessment area.

9.3.3 Capture Fisheries

9.3.3.1 As the Project is located inland, no capture fisheries were identified within or near the assessment area.

9.4 Impact Identification and Evaluation

9.4.1 Construction Phase

9.4.1.1 No direct loss of active fishpond will be resulted from the Project. Nevertheless, the fishponds and fish culture activities in close vicinity to the Project within assessment area may be affected by uncontrolled runoff, dust, silt and chemical waste arising from construction activities. Untreated runoff and sediment would raise the level of suspended solids, which can have acute or chronic effect on fish. As streams can be sources of water for fish ponds, pollutants discharging into the nearby streams may also eventually cause a fisheries impact.

9.4.1.2 Access road toward fish ponds affected and those in the vicinity may also be blocked temporarily by construction works, which may have an impact on management activities and fisheries production. However, the current extent of this impact is unknown.

9.4.2 Operational Phase

9.4.2.1 No fisheries impacts during the operational phase of the Project have been identified. Operational phase indirect impacts are considered to be negligible.

9.4.3 Cumulative Impacts

9.4.3.1 A number of concurrent projects have been identified for the evaluation of any potential cumulative impacts during both construction and operational phases of the Project. Detailed descriptions of these projects have been provided in Section 2.

9.4.3.2 These projects are not expected to result in significant loss of fisheries resources, nor to disturb fisheries operations in the wider area. Hence, no significant cumulative impacts are anticipated.

9.5 Mitigation Measures

9.5.1.1 Although the impact on fisheries during construction phase is considered insignificant, good site practises as specified in the Practice Note for Professional Persons on Construction Site Drainage, Environmental Protection Department, 2023 (ProPECC PN 2/23) should be followed to prevent potential indirect impacts on the pond area.

9.5.1.2 Standard mitigation measures to control site runoff and other pollutants caused by construction activities and good site practices will be implemented during the construction phase of the Project. As for surface runoff, implementation of the recommended mitigation measures for water quality impacts would prevent the adverse water quality impacts to the nearby environment. (see Section 5) Excavated material and other inert construction wastes produced will also be transferred to proper recipients as discussed in Section 6.

9.5.1.3 Temporary traffic arrangements should be instigated to maintain or provide alternative access to ponds during construction phase (should it be required). The detailed arrangement can be discussed with the Contractor before the construction period. The access to the fish ponds will not be blocked in the operational phase.

9.6 Residual Impacts

9.6.1.1 With full implementation of the above mitigation measures, no significant and adverse residual impacts during construction and operational of the Project are anticipated.

9.7 Environmental Monitoring and Audit (EM&A)

9.7.1.1 No specific fisheries monitoring and audit programme is required.

9.8 Conclusion and Recommendations

9.8.1.1 Significant fisheries impacts on culture fisheries are not anticipated from the Project. Indirect impacts arising from the Project during the construction phase would be properly mitigated through standard practices and thus no significant fisheries impact is expected to occur. Overall, no unacceptable fisheries impact is predicted from the Project.

9.8.1.2 In addition, consultation with pond owners/operator prior to the commencement of the works is recommended throughout the process in order for transparency and courtesy.

9.9 References

Agriculture, Fisheries and Conservation Department (AFCD). 2018.
Report on Port Survey 2016/17. Downloaded from https://www.afcd.gov.hk/english/fisheries/fish_cap/fish_cap_latest/ files/common/PS201617_ENG.pdf

10 Landscape and Visual Impact

10.1 Legislation, Standards and Guidelines

10.1.1 General

10.1.1.1 The Landscape and Visual Impact Assessment (LVIA) follows the criteria and guidelines as stated in Annexes 10 and 18 of the EIAO-TM. Colour photographs showing baseline conditions, and photomontages and illustrative materials supporting conclusions are provided and the locations of all key viewpoints shall be clearly mapped. Photomontages at representative locations provide comparison between existing views, proposals on day 1 after completion without mitigation measures, on day 1 after completion with mitigation measures, and in year 10 after completion with mitigation measures in accordance with EIAO Guidance Note No. 8/2010.

10.1.2 Legislation, Standards and Guidelines

10.1.2.1 The relevant legislations, standards and guidelines applicable to the LVIA include:

· EIAO (Cap. 499) and EIAO-TM, particularly Annexes 10 (Criteria for Evaluating Visual and Landscape Impact, and Impact on Sites of Cultural Heritage) and 18 (Guidelines for Landscape and Visual Impact Assessment);

· EIAO Guidance Note 8/2010 (Preparation of Landscape and Visual Impact Assessment under the EIAO);

· Town Planning Ordinance (Cap. 131);

· Hong Kong Planning Standards and Guidelines (HKPSG);

· Landscape Character Map of Hong Kong (2005 Edition);

· Study on Landscape Value Mapping of Hong Kong;

· Government General Regulation 740 – sets out restrictions on the preservation and felling of trees in Hong Kong;

· Agriculture, Fisheries and Conservation Department (AFCD) Nature Conservation Practice Note (NCPN) No.2 - Measurement of Diameter at Breast Height (DBH);

· AFCD Publication – Rare and Precious Plants of Hong Kong (2003);

· AFCD Publication – Check List of Hong Kong Plants 2012;

· AFCD NCPN No. 02 – Measurement of Diameter at Breast Height (DBH);

· Development Bureau (DEVB) Technical Circular (TC) (W) No. 5/2017 - Community Involvement in Planting works;

· DEVB TC(W) No. 5/2020 - Registration and Preservation of Old and Valuable Trees;

· DEVB TC(W) No. 4/2020 - Tree Preservation;

· DEVB TC(W) No. 6/2015 - Maintenance of Vegetation and Hard Landscape Features;

· DEVB TC(W) No. 3/2012 - Site Coverage of Greenery for Government Building Projects;

· DEVB TC(W) No. 2/2012 - Allocation of Space for Quality Greening on Roads;

· Environment, Transport and Works Bureau (ETWB) TCW No. 8/2005 - Aesthetic Design of Ancillary Buildings in Engineering Projects;

· ETWB TCW No. 36/2004 – The Advisory Committee on the Appearance of Bridges and Associated Structures (ACABAS);

· Civil Engineering and Development Department (CEDD) Technical Circular No. 5/2018 – Vetting Committee on Slope Appearance;

· Geotechnical Engineering Office (GEO) Publication 1/2011 - Technical Guidelines on Landscape Treatment for Slopes;

· GEO Publication (1999) - Use of Vegetation as Surface Protection on Slopes;

· Lands Administration Office Practice Note (LAO PN) No. 1/2020 - Compliance of Landscape Clause under Lease;

· LAO PN No. 2/2020 - Tree Preservation and Removal Proposal for Building Development in Private Projects-Compliance of Tree Preservation Clause under Lease;

· Guidelines on Tree Transplanting (9/2014), Greening, Landscape and Tree Management (GLTM) of DEVB;

· Guidelines on Tree Preservation during Development (4/2015), GLTM of DEVB;

· Green Infrastructure, GLTM of DEVB – Website:
https://www.greening.gov.hk/en/greening-landscape/greening-landscape-trends/index.html;

· Measures on Tree Preservation, GLTM of DEVB – Website:
https://www.greening.gov.hk/en/tree-care/tree-care-practices/index.html;

· Drainage Services Department (DSD). 2015. DSD Practice Note No. 1/2015 – Guidelines on Environmental and Ecological Considerations for River Channel Design;

· Restrictions on the preservation and felling of trees in Hong Kong are specified in Government General Regulation 740. The Forests and Countryside Ordinance (Cap. 96) prohibits felling, cutting, burning or destroying of trees and growing plants in forests and plantations on government land. Its subsidiary regulations prohibit the picking, felling or possession of listed rare and protected plant species. The list of protected species in Hong Kong is defined in the Forestry Regulations, made under Section 3 of the Forests and Countryside Ordinance (Cap. 96); and

· Environmental Protection Department (EPD), 9/2019, Guidelines on Handling Yard Waste for Recycling and Disposal.

10.2 Assessment Methodology

10.2.1.1 The assessment includes:

· a definition of the scope and contents of the study, including a description of the assessment methodology;

· a review of the relevant planning and development control framework;

· a review of comments received during earlier public consultations and how these comments have been addressed in the design;

· a baseline study providing a comprehensive and accurate description of the baseline landscape resources, landscape character areas and visually sensitive receivers (VSRs);

· identification of the potential landscape and visual impacts and prediction of their magnitude and potential significance, before and after the mitigation measures;

· recommendation of appropriate mitigation measures and associated implementation programmes; and

· an assessment of the acceptability or otherwise of the predicted residual impacts, according to the five criteria set out in Annex 10 of the EIAO-TM.

10.2.2 Assessment Methodology – Landscape Impact

10.2.2.1 Pursuant to Section 5(7)(a) of the EIAO, the Director of Environmental Protection (DEP) issued a Study Brief (SB) (No.: ESB-333/2020) dated 14 September 2020 for the EIA Study, in which requires a 500m assessment area of the Project for the landscape impact assessment. The landscape impacts have been assessed according to the following procedures:

Identification of Baseline Landscape Study about Landscape Resources (LRs) and Landscape Character Areas (LCAs) found within the Assessment Area

10.2.2.2 This is achieved by site visits and desktop study of topographical maps, information databases and photographs.

Assessment of the Degree of Sensitivity of the LRs and LCAs and the Classification (rating) of sensitivity of each LR and LCA

10.2.2.3 This is influenced by a number of factors including whether the resource /character is common or rare, whether it is considered to be of local, regional, national or global importance, whether there are any statutory or regulatory limitations / requirements relating to the resource, the quality of the resource / character, the maturity of the resource and the ability of the resource / character to accommodate change.

10.2.2.4 The sensitivity of each LR and LCA is classified as follows:

· High – Important landscape or landscape resource of particularly distinctive character or high importance, sensitive to relatively small changes.

· Medium – Landscape or landscape resource of moderately valued landscape characteristics reasonably tolerant to change.

· Low – Landscape or landscape resource, the nature of which is largely tolerant to change.

Identification of Potential Sources of Landscape Impacts

10.2.2.5 These are the various elements of the construction works and operation procedures that would generate landscape impacts.

Identification of the Magnitude of Changes on LRs and LCAs and the Classification (rating) of the Magnitude of Changes for all LRs and LCAs

10.2.2.6 The magnitude of changes (or magnitude of impacts) depends on a number of factors including the physical extent of the impact, the landscape and visual context of the impact, the compatibility of the assessment area with the surrounding landscape; and the time-scale of the impact, i.e. whether it is temporary (short, medium or long term), permanent but potentially reversible, or permanent and irreversible. Landscape impacts are quantified wherever possible.

10.2.2.7 The Magnitude of Landscape Impacts are classified as follows:

· Large – The landscape or landscape resource would suffer a major change.

· Intermediate – The landscape or landscape resource would suffer a moderate change.

· Small – The landscape or landscape resource would suffer slight or barely perceptible change.

· Negligible – The landscape or landscape resource would suffer no discernible change.

Significant Threshold of Potential Landscape Impact (before mitigation) during Construction and Operation Phases

10.2.2.8 By synthesising the magnitude of the various impacts and the sensitivity of the various LRs / LCAs, it is possible to categorise impacts in a logical, well-reasoned and consistent fashion. Table 10.1 show the rationale for dividing the degree of significant into four thresholds, namely insubstantial, slight, moderate, and substantial, depending on the combination of a negligible- small-intermediate – large magnitude of change and a low- medium- high degree of sensitivity of LR / LCA.

Table 10.1 – Relationship between Sensitivity of LR/LCA and Magnitude of Change in Defining Landscape Impact Significance

		Sensitivity of LR / LCA
		Low	Medium	High
Magnitude of Change (Both Adverse and Beneficial Impact are assessed)	Large	Moderate	Moderate / Substantial	Substantial
	Intermediate	Slight / Moderate	Moderate	Moderate / Substantial
	Small	Insubstantial / Slight	Slight / Moderate	Moderate
	Negligible	Insubstantial	Insubstantial	Insubstantial
Note: [1] All impacts are adverse unless otherwise noted with beneficial.

10.2.2.9 The Significance of Landscape Impacts are categorised as follows:

· Substantial – Adverse / beneficial impact where the proposal would cause significant deterioration or improvement in existing landscape quality.

· Moderate – Adverse / beneficial impact where the proposal would cause a noticeable deterioration or improvement in existing landscape quality.

· Slight – Adverse / beneficial impact where the proposal would cause a barely perceptible deterioration or improvement in existing landscape quality.

· Insubstantial – No discernible change in the existing landscape quality.

10.2.3 Assessment Methodology – Visual Impact

10.2.3.1 The assessment area for the visual impact assessment is defined by the zone of visual influence (ZVI) of the Project. The assessment of visual impacts has involved the following procedures:

Identification of ZVI during Construction and Operation phases of the Site

10.2.3.2 This is achieved by site visit and desktop study of topographic maps and photographs, and preparation of cross-sections to determine visibility of the assessment area from various locations. The ZVI will be achieved by computer model where practical, as well as site visits and desktop study of topographic maps and photographs. Distance and other factors will be considered, to determine the ZVI and the visibility of the assessment area from various locations. The ZVI is that area from which any part of the proposed Development can be seen; usually defined by natural mountain backdrop, man-made features, road infrastructures, etc.

Identification of Visually Sensitive Receivers (VSRs) within ZVI

10.2.3.3 In the interest of the public, it is far more important to protect public views, particularly those easily accessible and popular to the public, and VIA should primarily assess the impact on sensitive public viewers from the most affected viewing points. VSR’s views were studied through desktop analysis and on-site inspection. There are many VSRs within a ZVI and those of similar sensitivity have been grouped. Key public viewpoint locations (i.e. VPs) are representative of the VSRs have been selected to assess the visual impact by the proposed development. Photomontages give indicative illustrations of the impacts from the VP have been selected to provide a combined broad indication of how the assessment area will look overall. The photomontages provide a comparison between existing views, the assessment area after completion without mitigation measures and with mitigation measures. VSRs can be categorised by type.

Assessment of the Degree of Sensitivity of the VSRs

10.2.3.4 Factors considered when assessing VSR sensitivity include the type of VSR, value and quality of existing views, availability and amenity of alternative views, type and estimated number of receiver population, duration or frequency of view, and degree of visibility. The type of VSR is classified according to whether a person is at home, at work, at play, or travelling:

a) Those who view the impact from homes are considered to be highly sensitive as the character of view from their home will have a substantial effect on their perception of quality and acceptability of their home environment and their general quality of life. This is similar to people residing in temporary accommodation such as hotels as the view is a key pricing factor in the room cost. These VSRs are termed ‘Residential’ VSRs (RES) and are generally highly sensitive to change.

b) Those who view the impact from their recreational and leisure activities are considered to be relatively less sensitive as the character of view is considered to have a less important effect on their perception of quality of life. These VSRs are termed ‘Recreational’ VSR (REC) are considered to be less sensitive to change than residential VSRs.

c) Those who view the impact from their occupational offices will display varying sensitivity depending on nature and view. These VSRs are termed ‘Occupational’ VSRs and generally have the medium sensitivity to change.

d) Those who view the impact while travelling in public / private vehicles or on foot will display varying sensitivity depending on the speed, nature and frequency of travel. These VSRs are termed ‘Travelling’ VSRs and generally have the lowest sensitivity to change.

10.2.3.5 The Sensitivity of the VSRs are classified as follows:

· High – The VSR is highly sensitive to any change in their viewing experience.

· Medium – The VSR is moderately sensitive to any change in their viewing experience.

· Low – The VSR is only slightly sensitive to any change in their viewing experience.

Identification of the Potential Sources of Visual Impact

10.2.3.6 These are the various elements of the construction works and operation procedures that have the potential to cause visual impacts.

Identification of the Potential Magnitude of Change about Visual Impacts

10.2.3.7 The magnitude of changes (or magnitude of impacts) depends on a number of factors including the compatibility of the assessment area with the surrounding landscape; duration of impacts; scale of development; reversibility of the impact; distance of the source of impact from the viewer; and degree of visibility of the impact and the degree that the impact dominates the field of vision of the viewer.

10.2.3.8 The Magnitude of Change is classified as follows:

· Large – The VSRs will experience a major change in the character of their existing views.

· Intermediate – The VSRs will experience a moderate change in the character of their existing views.

· Small – The VSRs will experience a small change in the character of their existing views.

· Negligible – The VSRs will experience no discernible change in the character of their existing views.

Significant Threshold of Potential Visual Impact (before mitigation) during Construction and Operation Phases

10.2.3.9 By synthesising the magnitude of the various impacts and the sensitivity of the various VSR it is possible to categorise impacts in a logical, well-reasoned and consistent fashion. Table 10.2 shows the rationale for dividing the degree of significant into four thresholds, namely insubstantial, slight, moderate, and substantial, depending on the combination of a negligible - small - intermediate – large magnitude of change and a low – medium - high degree of sensitivity of VSR.

Table 10.2 – Relationship between Sensitivity of VSRs and Magnitude of Change in Defining Visual Impact Significance

		Sensitivity of VSR (Receptor)
		Low	Medium	High
Magnitude of Change	Negligible	Insubstantial	Insubstantial	Insubstantial
	Small	Slight	Slight / Moderate*	Moderate
	Intermediate	Slight / Moderate*	Moderate	Moderate / Substantial*
	Large	Moderate*	Moderate / Substantial*	Substantial
Note: * In those instances where the lower level of impact is predicted, this is “to be” justified in the description of the impact.

10.2.3.10 The Significant of Visual Impacts are defined as follows:

· Significant – Adverse / beneficial impact where the Site will cause significant deterioration or improvement in existing visual quality.

· Moderate – Adverse / beneficial impact where the Site will cause a noticeable deterioration or improvement in existing visual quality.

· Slight – Adverse / beneficial impact where the Site will cause a barely perceptible deterioration or improvement in existing visual quality.

· Insubstantial – The impact will cause no discernible change in the existing visual quality.

10.2.4 Identification of Potential Mitigation Measures

Assessment of the Potential Landscape and Visual Mitigation Measures ^[1]

10.2.4.1 These may take the form of adopting alternative designs or revisions to the basic engineering and architectural design to prevent and / or minimise adverse impacts, remedial measures such as colour and textural treatment of built structures and greening of those structures; compensatory measures such as tree planting and the implementation of landscape and visual design measures to compensate for unavoidable adverse impacts and to attempt to generate potentially beneficial long-term impacts.

Prediction of the Significance of Landscape Impacts before and after the Implementation of the Mitigation Measures

10.2.4.2 By synthesizing the magnitude of the various impacts and the sensitivity of the various landscape resources, it is possible to categorise impacts in a logical, well-reasoned and consistent fashion. Section 10.3.1.9 shows the rationale for dividing the degree of significance into four thresholds, namely Insubstantial, Slight, Moderate, and Substantial, depending on the combination of a negligible-small-intermediate-large magnitude of change and a low-medium-high degree of sensitivity of LRs and LCAs.

Prediction of the Significance of Visual Impacts before and after the Implementation of Mitigation Measures

10.2.4.3 By assessing the magnitude of change and the sensitivity of VSRs, the degree of significance of the impacts are categorised in a logical, well-reasoned and consistent manner. Section 10.3.2.10 shows the rationale for dividing the degree of significance into four thresholds, namely, Insubstantial, Slight, Moderate and Significant, depending on the combination of a negligible-small-intermediate-large magnitude of change and a low-medium-high degree of sensitivity of VSRs.

10.2.5 Identification of Residual Impact

10.2.5.1 This part of the assessment describes any unavoidable residual adverse landscape and visual impacts to LRs, LCAs and VSRs. Residual impacts are those which remain post implementation of mitigation measures i.e. 10-15 years after commissioning of the development.

10.2.5.2 The level of impact is derived from the magnitude of change which the development will cause to the LR, LCA or VSR taking into account its ability to tolerate change and effectiveness of mitigation measures.

10.2.6 Overall Conclusion of LVIA

10.2.6.1 An overall conclusion is made on the development based on the identified landscape and visual impacts as described.

Table 10.3 – Residual Impact Assessment Methodology

Overall Result of LVIA	Description
Beneficial	The impact is beneficial if the Site will complement and enhance the landscape value and visual character of its setting, will follow the relevant planning objectives and will improve overall landscape and visual quality.
Acceptable	The impact is acceptable if the assessment indicates that there will be no significant effects on the landscape, no significant visual effects caused by the appearance of the Site, or no interference with key views.
Acceptable with mitigation measures	The impact is acceptable with mitigation measures if there will be some adverse effects, but these can be eliminated, reduced or offset to a large extent by specific measures.
Unacceptable	The impact is unacceptable if the adverse effects are considered too excessive and are unable to mitigate practically.
Undetermined	The impact is undetermined if significant adverse effects are likely, but the extent to which they may occur or may be mitigated cannot be determined from the study. Further detailed study will be required for the specific effects in question.

10.2.7 Prediction of Acceptability of Landscape and Visual Impacts

10.2.7.1 The criteria and matrices used to determine the degree of impact described in the above sections. Both landscape and visual impacts are products of magnitude of change and the relative sensitivity of the sensitive receiver. Ultimately, the acceptability of the Project is dependent upon the significance of the residual impacts in accordance with the five criteria set out in Annex 10 of the EIAO-TM, namely ‘beneficial’, ‘acceptable’, ‘acceptable with mitigation measures’, ‘unacceptable’ and ‘undetermined’.

10.3 Review of Planning and Development Control Framework

10.3.1.1 A review has been undertaken of the current goals and objectives, statutory land-use and landscape planning designations for the assessment area. These have drawn upon information based up the Outline Zoning Plans (OZP) Nos.:

· S/YL-NSW/9 - Nam Sang Wai (Gazetted under Section 9(1)(a) on 27/10/2006);

· S/YL-MP7 – Mai Po & Fairview Park (Gazetted under Section 9(1)(a) on 18/02/2005);

· S/YL-KTN/11 - Kam Tin North (Gazetted under Section 5 on 06/01/2023); and

· S/YL-NTM/13 - Ngau Tam Mei (Gazetted under Section 9(1)(a) on 15/12/2006).

10.3.1.2 There are natural woodland, scrubland and country park of high landscape value found within the 500m from the boundary of the Project. The Project Works Area is predominantly located within Conservation Area (CA) and Green belt (GB) in Ngau Tam Mei. The modification of the underground existing raw water tunnel junction (Chamber G) will encroach in the Country Park (CP). The aerial photo is shown in Figures 10.1 and the OZP is shown in Figure 10.2.

10.4 Landscape Baseline Study

10.4.1.1 The assessment area for landscape impact assessment shall include all areas within a 500m distance from the boundary of the Project.

10.4.1.2 A landscape baseline study comprises of the identification and evaluation of the sensitivity of LRs and LCAs within the assessment area of landscape impact assessment, which is within a 500m from the boundary of the Project.

10.4.1.3 Landscape character zones have been identified within the assessment area in accordance with the Study on Landscape Value Mapping of Hong Kong. These are described in Table 10.4 and illustrated in Figure 10.3 and Figure 10.5. Photo views illustrating the LCAs within the assessment area are illustrated in Figures 10.4a-b and Figures 10.6a-b.

Table 10.4 – LR/LCA and Their Sensitivity

ID no.	Landscape Resources / Landscape Character Area	Sensitivity (Low, Medium or High)
LR1	Woodland / Natural Hillside Plantation
	This LR covers an area of approximately 188ha within the assessment area. The woodland is located on natural hillside in Kai Kung Leng in Yau Tam Mei in Lam Tsuen Country Park. Kwai Kok Shan (+585mPD) of Kai Kung Leng is the highest point of Lam Tsuen Country Park, which is a famous hiking trail in the vicinity. Atop the ridge of Kai Kung Leng, there are broad views of Yuen Long Plain, Nam Sang Wai, Mai Po and Deep Bay, set against Shenzhen in the far distance. According to the broad-brush tree survey result, the natural secondary woodlands within this LR contain mostly common native trees, with representative species like Schefflera heptaphylla, Cratoxylum cochinchinense, Schima superba, Pinus massoniana, Rhus succedanea, Machilus spp., Macaranga tanarius var. tomentosa, Sterculia lanceolata, Tetradium glabrifolium, Gordonia axillaris, Zanthoxylum avicennae and Aporusa dioica etc. These trees are generally mature and 6-15m in height. Trees found on man-made slopes are mostly exotic woodland plantation species e.g. Acacia spp., Eucalyptus spp., Casuarina equisetifolia, Lophostemon confertus and Pinus elliottii, interspersed with naturally regenerated native species e.g. Ficus hispida and Bridelia tomentosa, and exotic ruderal growth e.g. Bauhinia spp. and Melia azedarach. These trees are generally mature and 8-20m in height. The invasive weed tree Leucaena leucocephala is commonly found near roadside or disturbed areas. A number of Aquilaria sinensis, a tree species of conservation interest, were recorded within the accessible parts of this LR. These trees range from young to moderately mature and 6-13m in height. Their locations are indicated on the LR Plans (Figure 10.3). For details of these trees, please refer to the broad-brush tree survey report enclosed in Appendix 10.1. The woodland is district significant. The landscape quality is relatively high with little tolerance to change. The vegetation is moderately mature and in fair health condition. Therefore, the overall sensitivity of LR is considered as high.	High
LR2	Plantation within Ngau Tam Mei Water Treatment Works (NTM WTW)
	This LR covers an area of approximately 7.5ha within the assessment area. The plantation is located in the existing NTM WTW. There are approx. 1170 nos of trees within the NTM WTW. Majority of the Tree species includes, 542 nos. of Acacia confusa, 153 nos. of Leucaena leucocephala, 102 nos. of Macaranga tanarius var. tomentosa, 120 nos. of Ficus microcarpa, 36 nos. of Acacia mangium and 32 nos. of Celtis sinensis. The plantation is local significant. The vegetation is moderately mature and in fair health condition; trees are generally of 5-20m height. Therefore, the overall sensitivity of LR is considered as high.	High
LR3	(Not Used)
LR4	Agricultural Land
	This LR covers an area of approximately 1.3ha within the assessment area. This LR refers to the agricultural land in Tam Mei. These are small-sized agricultural lands fed by the nearby watercourse. According to the broad-brush tree survey, dominant tree species in this LR include common fruit trees like Dimocarpus longan, Litchi chinensis, Clausena lansium, Citrus maxima, Averrhoa carambola, Mangifera indica, Artocarpus heterophyllus, Psidium guajava, Carica papaya etc., as well as wild growth like Macaranga tanarius var. tomentosa, Celtis sinensis, Ficus microcarpa, Ficus variegata, Litsea glutinosa, Microcos nervosa, Cinnamomum camphora, Ligustrum sinense and Bridelia tomentosa etc. Ornamental species like Podocarpus macrophyllus, Archontophoenix alexandrae and Araucaria heterophylla etc. are commonly found amongst village houses. Trees in this LR range from young to mature and generally 4-15m in height. Other common crop plants in this LR include Brassica parachinensis, Cucurbita sp., Ipomoea batatas etc. This LR is local significant. This LR has a relatively moderate amenity value and quality. This LR is relatively able to tolerant to any development change, since it is a man-made resource and is able to be recreated reasonably easily. Therefore, the sensitivity of this LR is considered to be medium.	Medium
LR5	Roadside Plantation
	This LR covers an area of approximately 2.7ha within the assessment area. This LR refers to all the roadside plantation along the San Tin Highway, Tsing Long Highway, Yuen Long Highway, Shap Pat Heung Road, Long Tin Road. This LR provides good screening effect and enhance the overall landscape quality of the surrounding environment. These plantings are mainly common roadside amenity trees and shrubs to screen road alignment and associated structures along linear road network, namely, Eucalyptus spp., Aleurites moluccana, Melaleuca cajuputi subsp. Cumingiana, and Livistona chinensis. Trees in this LR range from young to mature and generally 6-20m in height. These roadside plantings are local significant and provide moderate amenity value to the existing environment. The landscape quality is fair with reasonable tolerance to change. Therefore, the sensitivity of LR is considered as medium.	Medium
LR6	(Not Used)
LR7	Modified Watercourse
	This LR covers an area of approximately 0.2ha within the assessment area. This LR refer to the channelised watercourses that run through Tam Mei area and along San Tam Road near Long Ha area. The channelised watercourses are mostly concrete lined with a dry weather flow channel at the base. The channelised watercourses provide relatively little landscape amenity and have high tolerance to change. Overall, the sensitivity of this LR is considered as medium.	Medium
LR8	Agricultural Fish Pond
	This LR covers an area of approximately 7.2ha within the assessment area. This LR refers to fish ponds with agricultural areas located in Man Yuen Chuen and Tam Mei next to NTM WTW. These ponds are man-made with landscape berm edges. They are fed by series of irrigation channels linking to streams emanating from local hillsides. Further, there are some fruits along the landscape berms, namely Mangifera indica, Dimocarpus longan, and Musa balbisiana. This LR are regional significant and provide high amenity value to the existing environment. This LR is considered as ‘high’ for landscape quality, and the overall sensitivity is considered as high.	High
LCA1	Upland and Hillside LCA
	These are large scale upland landscape in Kai Kung Leng; consist of hills and ridges, the area is dominated by secondary woodland. This hillside character creates a greenery backdrop to the district. Part of the Lam Tsuen Country Park is included within this LCA. This Landscape Character Area is approx. 201.9ha within the assessment area. Representative tree species and conditions are described in LR1. Given this LCA is highly important and significant to the adjacent district, and the quality and maturity are high; therefore, the sensitivity of this area is considered as high.	High
LCA2	River Channel LCA
	These area refers to the channelised watercourses that run through the Tam Mei area.  This Landscape Character Area is approx. 0.2 ha within the assessment area. This LCA provides positive and valuable visual relief to the local community. This LCA is important to the adjacent district, but due to the artificial nature of the river channel, the sensitivity of this area is considered as medium.	Medium
LCA3	Urban Peripheral Village LCA
	This Landscape Character Area is approx. 31.5ha within the assessment area. Several areas are identified as urban peripheral village landscape within the 500m landscape impact assessment area; namely, Ngau Tam Mei and Mo Fan Heung. Vegetation typically consists of scattered matures trees and orchards on the periphery of these villages. Orchards with common fruit trees like Dimocarpus longan, Litchi chinensis etc. could be found within and around the villages. Wild growth like Macaranga tanarius var. tomentosa, Celtis sinensis, Ficus microcarpa etc. are also common within and at the periphery of the villages. Given the urbanised nature of the area and the fair amenity value of the vegetation, the sensitivity of this LCA is considered as medium.	Medium
LCA4	(Not Used)
LCA5	Transportation Corridor LCA
	San Tin Highway is the major transportation corridor within the 500m landscape impact assessment area. San Tin Highway is part of the Route 9, which are an expressway connecting the San Tin and Lam Tei in Tuen Mun of New Territories. This Landscape Character Area is approx. 2.4ha within the assessment area. This landscape character area is generally in a linear form associated with highways and footpath. Mature roadside plantation along San Tin Highway creates a pleasant and strong tree boulevard effect which contribute to the delightful and refreshing travel experience. Trees in this LCA are represented by plantings on roadside verges and man-made slopes along San Tin Highway, and contain exotic species like Acacia confusa, Melaleuca cajuputi subsp. cumingiana, and Eucalyptus spp. which are middle-aged to mature, interspersed with natural recolonization of native trees and shrubs in young to moderate maturity. These trees are generally fair in condition and established well. The landscape amenity, significance, and quality of this LCA are high. Therefore, the sensitivity is considered to be High.	High

10.4.1.4 For landscape impact assessment purposes, broad-brush tree and individual tree surveys have been carried out for the project area under the following agreements to estimate the dominant species, maturity, rarity and any plant species of conservation interest, Old and Valuable Tree (OVT) ^[2], as well as Trees of Particular Interest (TPI) ^[3] and areas for tree preservation and landscape restoration, with reference to the EIA SB No. ESB – 333/2020. Refer to Appendix 10.1 for broad brush tree survey results for the area in the vicinity of Chamber G and Appendices 10.2 & 10.3 for the individual tree survey results for the areas along the fresh water trunk main alignment between NTM WTW and NTM FWPSR, and between Ching Yau Road and San Tam Road.

10.4.1.5 No Registered OVT was identified within the 500m assessment area for landscape impact assessment. Meanwhile, a number of TPIs, including mature trees with DBH of 1m or more as well as Aquilaria sinensis which are tree species of conservation interest, are recorded in the broad-brush tree survey (Appendices 10.1 and 10.3).

10.5 Visual Baseline Study

10.5.1 Visual Envelope

10.5.1.1 The assessment of visual impacts follows the criteria and guidelines for evaluating and assessing landscape and visual impacts as stated in Annexes 10 and 18 of the TM, and the EIAO Guidance Note No. 8/2010 “Preparation of Landscape and Visual Impact Assessment under the EIAO”. The visual envelope defines the area the assessment of visual impacts, which generally the view shed formed by natural/manmade features such as treelines and building blocks.

10.5.1.2 The visual envelope is expected to cover the fields of views from all sensitive viewers in direct sight of the proposed development. Prior to the actual ground inspection, the assessment area can be approximated through topographic map analysis manually or by computer simulation.

10.5.1.3 The proposed modification of the existing raw water tunnel junction (Chamber G) are located at the south-east side of NTM WTW. The visual envelope and popular locally vantage points within the viewshed generally formed by mountain backdrop of Kai Kung Leng (+570mPD) in the Ngau Tam Mei Area, which is within the Lam Tsuen Country Park.

10.5.1.4 The proposed fresh water trunk mains encroaching CA are approx. 750m long laying from the expanded NTM WTW to the NTM FWPSR mainly along an existing access road, and approx. 250m long within the “Waterworks Reserve” between Ching Yau Road and San Tam Road.

10.5.2 Visual Resources

10.5.2.1 The project site does not fall within the strategic vantage points identified in the Urban Design Guidelines under HKPSG.

10.5.2.2 The mountain backdrop of the Kai Kung Leng (+570mPD) in Lam Tsuen Country Park provides a dramatic natural green backdrop to the area, which forms the valuable natural visual resources as viewed from Ngau Tam Mei.

10.5.3 Visually Sensitive Receivers (VSRs)

10.5.3.1 The type of VSRs is classified according to whether the person is at home, at work, at play, or travelling. Those who view the impact from their homes are considered to be highly sensitive as the attractiveness or otherwise of the outlook from their home will have a substantial effect on their perception of the quality and acceptability of their home environment and their general quality of life. Those who view the impact from their workplace are considered to be only moderately sensitive as the attractiveness or otherwise of the outlook will have a less important, although still material, effect on their perception of their quality of life. The degree to which this applies depends on whether the workplace is industrial, retail or commercial. Those who view the impact whilst taking part in an outdoor leisure activity may display varying sensitivity depending on the type of leisure activity. Those who view the impact whilst travelling on a public thoroughfare will generally have low sensitivity.

10.5.3.2 The sensitivity of the VSRs shall also be determined by numbers of the individuals within the VSR category, the quality of existing views, availability of alternative views, minimum distance between VSRs and impact source, degree of visibility, duration of view and frequency of view. The identified VSRs at different levels are listed below and summarised in Table 10.5. The key VSRs are mapped in Figure 10.7.

10.5.3.3 At the strategic level, VSRs include:

· Hikers at Ngau Tam Shan (A1)

· Hikers at Kai Kung Leng (A2)

10.5.3.4 At the local level, VSRs include:

· Residents in village of Yau Tam Mei Tsuen (II) (R1)

· Residents in Fuk Hing Lei and nearby residential developments (R2)

· Residents in Pok Wai and nearby residential developments (R3)

Table 10.5 – Visually Sensitive Receivers

ID	VSRs	Types of VSR ^[1]	VSR Category ^[2]
A1	Hikers at Ngau Tam Shan	Recreational	Strategic
A2	Hikers at Kai Kung Leng	Recreational	Strategic
R1	Residents in village of Yau Tam Mei Tsuen (II)	Residential	Local
R2	Residents in Fuk Hing Lei and nearby residential developments	Residential	Local
R3	Residents in Pok Wai and nearby residential developments	Residential	Local
Note: [1] Type of VSRs (Residential / Recreational) [2] VSR Category (Strategic / Local)

10.5.3.5 The baseline assessment and sensitivity are summarised in Table 10.6. Photo views illustrating the VSRs within the assessment area are shown in Figures 10.8a-b.

Table 10.6 –VSRs and Their Sensitivity

ID	VSR	Number of Individuals ^[1]	Quality of Existing View ^[2]	Availability of Alternative Views (Yes/No)	Amenity of Alternative Views ^[2]	Degree of Visibility ^[3]	Duration of View ^[4]	Frequency of View ^[5]	Sensitivity ^[6]
									Construction	Operation
A1	Hikers at Ngau Tam Shan	MD	G	Yes	G	F	S	R	H	H
A2	Hikers at Kai Kung Leng	MD	G	Yes	G	G	S	R	H	H
R1	Residents in village of Yau Tam Mei Tsuen (II)	F	G	Yes	G	G	S	O	M	M
R2	Residents in Fuk Hing Lei and nearby residential developments	MD	G	Yes	G	G	S	R	M	M
R3	Residents in Pok Wai and nearby residential developments	MD	F	Yes	F	G	S	R	M	M
Notes: [1] Very Many (VM) / Many (M) / Medium (MD) / Few (F) [2] Good (G) / Fair (F) / Poor (P) [3] Full (F) / Partial (P) / Glimpse (G) [4] Long (L) / Medium (M) / Short (S) [5] Frequent (F) / Occasional (O) / Rare (R) [6] Low (L) / Medium (M) / High (H)

10.5.4 Photomontage Viewpoints (VPs)

10.5.4.1 Photomontage viewpoints (VPs) were selected as representative examples of the visual impact of the Project, which include the viewpoint from the following VSRs:

· Hikers at Ngau Tam Shan (A1) – Viewpoint from Ngau Tam Shan looking towards south-west was selected as representative of views from hikers, which provides direct views of the NTM WTW. The elevation of the viewpoint is approx. 150mPD;

· Hikers at Kai Kung Leng (A2) – Viewpoint from Kai Kung Leng looking towards north-east was selected as representative of views from hikers, which provides direct views of the NTM FWPSR. The elevation of the viewpoint is approx. 300mPD;

· Residents in village of Yau Tam Mei Tsuen (II) (R1) – Viewpoint from Ngau Tam Mei looking toward east was selected as representative of views from residents, which is the residential area close to the NTM WTW. The elevation of the viewpoint is approx. 15mPD; and

· Residents in Fuk Hing Lei and nearby residential developments (R2) – Viewpoint from Fuk Hing Lei was selected as representative of views from residents, drivers and passengers, which provides a view along the fresh water trunk main alignment. The elevation of the viewpoint is approx. 12.5mPD.

10.5.4.2 The location of photomontage VPs are shown in Figure 10.9 and the photomontages of the selected VPs are shown in Figures 10.10a-d, with photos showing the “Existing Baseline Conditions”, “Day 1 in Operation Stage (without Mitigation)”, “Day 1 in Operation Stage (with Mitigation)”, and “Year 10 in Operation Stage (with Mitigation)”.

10.6 Source of Landscape and Visual Impact Assessment

10.6.1.1 The nature and scope of works are described in Sections 1-2. Several sources of landscape and visual impacts have been identified as follows.

10.6.1.2 During construction phase landscape and visual impacts can be resulted from the following sources:

· Site clearance works, including removal of any obstacles, and existing vegetation/trees;

· Excavation and slope stabilisation;

· Construction vehicles & temporary traffic arrangement;

· Presence of construction machinery and equipment; temporary parking areas, construction storage, site offices and facilitates of works area(s);

· Night lighting and welding;

· Temporary works hoardings, barriers and enclosures; and

· Construction dust and waste materials.

10.6.1.3 During the operational phase landscape and visual impacts can be resulted from the following sources:

· Any on-going changes in the quality or quantity of LRs resulting from the Project; and

· Loss of visual amenity previously present at the Project site.

Table 10.7 – Sources of Landscape and Visual Impacts

Sources of Impact	Descriptions	Brief Description of Landscape and Visual Impact of the Works
Proposed modification of Chamber G	Modification of the underground existing raw water tunnel junction (Chamber G)	Underground works, therefore considered as no impact.
Reinstatement of access road	Reinstatement of access road due to laying of new underground fresh water trunk mains	Existing landscape cover and trees along the footprint of the new trunk mains will be removed.
Slope stabilisation	Slope stabilisation is required for slopes along the access road between NTM WTW and FWPSR	Existing slope trees might be affected.
Fresh water trunk mains laying works	The fresh water trunk mains laying works along access road between NTM WTW and NTM FWPSR and within the waterworks reserve between Ching Yau Road and San Tam Road.	The main laying works would be mostly carried out along the existing access roads, and the waterworks reserve between Ching Yau Road and San Tam Road. Tree removal is avoided as far as practicable.

Magnitude of Change of Landscape Quality without Mitigation

10.6.1.4 The magnitude of the impacts, before implementation of mitigation measures, on the LRs and LCAs that would occur in the construction phase and operational phase are described below and tabulated in Table 10.8.

Table 10.8 – Landscape Impacts of the Proposed Works during Construction Phase

ID	LR/ LCA	Source of Impact	Description of Impacts	Magnitude of impact (Large/ Medium/ Small/ Negligible)
				Construction	Operation
LR1	Woodland / Natural Hillside Plantation	Proposed modification of Chamber G; and re-instatement of access road	- It is anticipated that LR1 would be affected due to the proposed modification of Chamber G, main laying along access road between NTM WTW and NTM FWPSR, re-instatement of access road and slope stabilisation works on a number of natural and man-made slopes at the south side of the access road between NTM WTW and NTM FWPSR. It is estimated that approx. 140 nos. of trees (excluding Leucaena leucocephala), mostly exotic woodland plantation species like Acacia spp., Eucalyptus spp., Casuarina equisetifolia, and Lophostemon confertus etc., would be affected by these works in this LR. - None of the recorded Aquilaria sinensis would be affected by the proposed works.	Small	Negligible
LR2	Plantation within NTM WTW	None	Nil	Negligible	Negligible
LR4	Agricultural Land	None	Nil	Negligible	Negligible
LR5	Roadside Plantation	None	Nil	Negligible	Negligible
LR7	Modified Watercourse	None	Nil	Negligible	Negligible
LR8	Agricultural Fish Pond	None	Nil	Negligible	Negligible
LCA1	Upland and Hillside LCA	Proposed modification of Chamber G; and re-instatement of access road	- It is anticipated that LCA1 would be affected due to the Proposed modification of Chamber G, extension of NTM FWPSR, main laying along access road between NTM WTW and NTM FWPSR, re-instatement of access road and slope stabilisation works on a number of natural and man-made slopes at the south side of the access road between NTM WTW and NTM FWPSR. It is estimated that approx. 140 nos. of trees (excluding Leucaena leucocephala), mostly exotic woodland plantation species like Acacia spp., Eucalyptus spp., Casuarina equisetifolia, and Lophostemon confertus etc., would be affected by these works in this LCA. - It is anticipated that LCA1 would also be affected by the mainlaying and reinstatement works between Ching Yau Road and San Tam Road. It is estimated that approx. 100 nos. of trees (excluding Leucaena leucocephala), mostly Acacia confuse, Celtis sinensis Ficus hispida, Ficus macrocarpa, Macaranga tanarius var. tomentosa, etc. would be affected by these works in this LCA.	Small	Negligible
LCA2	River Channel LCA	None	Nil	Negligible	Negligible
LCA3	Urban Peripheral Village LCA	None	Nil	Negligible	Negligible
LCA4	Residential Urban Fringe LCA	None	Nil	Negligible	Negligible
LCA5	Transport-ation Corridor LCA	None	Nil	Negligible	Negligible

Magnitude of Change of Visual Quality without Mitigation

10.6.1.5 The magnitude of change in visual quality of the VSRs depend on a number of factors including compatibility of the Project with the surrounding visual environments, duration of impacts, scale of development, reversibility of change, viewing distance and blockage of view. Table 10.9 summarises magnitude of change in visual quality of VSRs before mitigation.

Table 10.9 – Magnitude of Impacts on VSRs during Construction & Operation

VSR ID	Key VSR	Blockage of View ^[1]	Approx. Closest Viewing Distance to Proposed works	Scale of Development ^[2]	Compatibility with Surrounding Landscape ^[3]	Reversibility of Change ^[4]	Duration of Impact ^[5]		Magnitude of Impacts ^[6]
							Construction	Operation	Construction	Operation
A1	Hikers at Ngau Tam Shan	N	650m	S	F	I	T	P	S	N
A2	Hikers at Kai Kung Leng	N	1050m	S	F	I	T	P	S	N
R1	Residents in village of Yau Tam Mei Tsuen (II)	N	350m	S	F	R	T	P	N	N
R2	Residents in Fuk Hing Lei and nearby residential developments	N	1700m	S	F	R	T	P	N	N
R3	Residents in Pok Wai and nearby residential developments	N	200m	S	F	R	T	P	N	N
Notes: [1] Full (F) / Partial (P) / Glimpse (G) / Nil (N) [2] Large (L) / Medium (M) / Small (S) [3] Good (G) / Fair (F) / Poor (P) [4] Reversible (R) / Irreversible (I) [5] Temporary (T) – Short, Medium Term / Permanent (P) – Long Term [6] Large (L) / Intermediate (I) / Small (S) / Negligible (N)

10.6.1.6 During the construction phase, the construction site (including the temporary construction storage area and temporary road works for mainlaying) for the proposed modification works at Chamber G and mainlaying works along access road between NTM WTW and NTM FWPSR, and between Ching Yau Road and San Tam Road is considered to be fairly compatible with the surrounding urban visual context. The visible portion(s) of the Project is considered to be a small scale of development in the local area. The duration of the fresh water trunk mains laying works is considered to be ‘medium’.  The Project will not result in blockage of the views of all types of VSRs. Only the VSRs (including A1 and A2) who might see the construction site for the proposed works will experience a small level of change in their visual quality.

10.6.1.7 During the operational phase of the Project, all the temporary road works area(s) for laying of fresh water trunk mains will be reinstated back to their original conditions.  As such, the Project site is considered to be of small-scale and fairly compatible with the surrounding hillside landscapes as it is sheltered by surrounding vegetation. No visual change will be resulted during the operation of the Project.

10.7 Recommended Landscape and Visual Mitigation Measures

10.7.1.1 The previous sections have identified the potential landscape and visual impacts due to the proposed modification of Chamber G, fresh water trunk mains laying works between NTM WTW and NTM FWPSR, and between Ching Yau Road and San Tam Road, and re-instatement of access road.

10.7.1.2 A series of mitigation measures have been formulated in order to alleviate some of the effects of these impacts where possible, while some mitigation measures are targeted to provide the potential landscape visual enhancement. The project layout has sought to minimise any potential landscape and visual impact as much as possible. Unavoidably, some adverse landscape and visual impact would still be anticipated. As a result, the following recommended landscape and visual mitigation measures are proposed to alleviate the potential adverse landscape and visual impact for construction phase as listed in Table 10.10 and shown in Figure 10.10e.

Table 10.10 – Recommended Landscape and Visual Mitigation measures for Construction Phase

ID	Landscape and Visual Mitigation Measures for Construction Phase	Objectives or Justifications for the Mitigation Measures	Implementation Agency
CM1	Careful Site Planning and Management Site layout and works area including temporary access road(s), stockpiling area(s), temporary construction storage shall be carefully planned to preserve existing landscape resources and trees as far as practicable.	To minimise site clearance, tree removal and disturbance to existing Landscape Resources	WSD
	Good site practices shall be enforced to eliminate eyesores from unappealing stockpiling/ storage areas and/or construction activities.	To minimise visual obstruction to VSRs
CM2	Careful Design of Slope Works, if any Slope stabilisation methods (i.e. insertion of soil nails and establishment of grillage, etc.) shall be carefully formulated to minimise the loss of tree and landscape cover as far as practicable.	To minimise tree removal and to create a slope surface better blending with the surrounding environment	WSD
CM3	Tree Preservation In accordance with DEVB TC (W) No.4/2020 – Tree Preservation or its latest version, existing vegetation shall be retained on site as far as practicable. Adequate tree protection measures shall be provided for the Trees to be retained on site. Relevant guidelines on tree care and protection promulgated by Greening, Landscape and Tree Management Section of Development Bureau shall be observed and followed. Incorporating requirements for preservation and protection of existing trees in construction contracts.	To minimise tree removal	WSD
CM4	Tree Transplanting/ Compensatory Tree Planting Trees unavoidably affected by the project shall be transplanted as far as practicable in accordance with DEVB TC (W) No.4/2020 – Tree Preservation or its latest version and the latest guidelines promulgated by Greening, Landscape and Tree Management Section of Development Bureau. Affected trees that are not suitable for transplantation and to be felled shall be compensated in not less than 1:1 in quantity and in accordance with DEVB TC (W) No.4/2020 – Tree Preservation or its latest version, subject to the approved Tree Preservation and Removal Plan.  Tree species selected shall be compatible with surrounding existing vegetation.	To minimise the loss of trees  To compensate for the loss of trees To provide quality and sustainable landscape that is compatible with the site context	WSD
CM5	Regular Inspection of retained Trees Regular site inspection shall be conducted by tree specialist. The performance of the retained trees shall be monitored throughout the Construction period on a monthly basis by a qualified Arborist. The Contractor shall submit monthly record photo throughout the construction period for all retained trees, to demonstrate the trees’ health condition. The monthly record photos shall be prepared by a tree specialist or a qualified arborist, and endorsed by a registered Landscape Architect (RLA).	To closely monitor the retained trees’ health condition.	WSD
CM6	Minimisation of Light Impact Lighting at construction sites shall be carefully controlled at night.	To avoid disturbance to nearby VSRs	WSD
CM7	Reinstatement of Temporarily Disturbed Areas Temporarily disturbed areas shall be reinstated.	To reinstate the disturbed landscape	WSD

10.7.1.3 Based on individual and broad-brush tree survey, it is estimated that 200-300 nos. of trees (excluding Leucaena leucocephala (銀合歡)) will be affected by the proposed fresh water trunk main laying works and slope stabilisation works, and are proposed to be removed due to low “Suitability for Transplanting”. The project proponent is committed to compensate for the loss of trees in not less than 1:1 ratio in terms of quantity, it is anticipated that compensatory trees will be under WSD’s vegetation maintenance, subject to further review and discussion with WSD on the availability of land. The locations for compensatory tree planting will be provided in due course after agreement with WSD and other relevant government departments.

10.7.1.4 The potential significance of landscape impacts during the construction and operational phases are tabulated in Table 10.11.

Table 10.11 – Significance threshold of residual impact before & after mitigation: Operation Day 1 & Year 10

ID	Landscape Resources / Landscape Characters	Sensitivity ^[2]	Magnitude of Change ^[3,4]		Impact Significance Threshold BEFORE Mitigation ^[4]		Recommended Mitigation Measures	Residual Impact Significance Threshold AFTER Mitigation ^[4]
			Construction	Operation	Construction	Operation		Construction	Operation^[5]
									DAY 1	YEAR 10
Landscape Resources
LR1	Woodland / Natural Hillside Plantation	H	S	N	SL	I	CM1-CM7	I	I	I
LR2	Plantation within Ngau Tam Mei Water Treatment Works	H	N	N	I	I	N/A	I	I	I
LR4	Agricultural Land	M	N	N	I	I	N/A	I	I	I
LR5	Roadside Plantation	M	N	N	I	I	N/A	I	I	I
LR7	Modified Watercourse	M	N	N	I	I	N/A	I	I	I
LR8	Agricultural Fish Pond	H	N	N	I	I	N/A	I	I	I
Landscape Character Areas
LCA1	Upland and Hillside LCA	H	S	N	SL	I	CM1-CM7	I	I	I
LCA2	River Channel LCA	M	N	N	I	I	N/A	I	I	I
LCA3	Urban Peripheral Village LCA	M	N	N	I	I	CM1-CM7	I	I	I
LCA4	Residential Urban Fringe LCA	M	N	N	I	I	N/A	I	I	I
LCA5	Transportation Corridor LCA	H	N	N	I	I	CM1-CM7	I	I	I
Note: [1] All impacts are Adverse unless otherwise noted as Beneficial [2] Low (L) / Medium (M) / High (H) [3] Large (L) /Medium (M) / Small (S) / Negligible (N) [4] Insubstantial (I) / Slight (SL) / Moderate (M) / Substantial (S) [5] No mitigation measure is required during the operational phase.

10.8 Visual Impact Assessment

Potential Sources of Visual Impacts

10.8.1.1 The sources of visual impacts due to the Project would create varying levels of visual impact during the construction and operational phases. Potential impacts would result from the elements stated in Section 10.7.

Nature & Magnitude of Unmitigated Visual Impacts in Construction and Operation

10.8.1.2 The magnitude of the impacts, before implementation of mitigation measures, on the VSRs that would occur in the construction and operational phases are described below and tabulated in Table 10.9. The residual impact significant threshold during construction, Day 1 operation, and Year 10 operational phase are tabulated in Table 10.12.

10.8.1.3 The magnitude of impacts is considered to be small for Hikers at Ngau Tam Shan (A1) and Hikers at Kai Kung Leng (A2), as they are visible to the proposed works. The major source of visual impacts will be the proposed fresh water trunk mains laying works, in which existing trees within the footprint of the proposed works will be removed.

10.8.1.4 For VSRs at local level, Residents in village of Yau Tam Mei Tsuen (II) (R1), Residents in Fuk Hing Lei and nearby residential developments (R2) and Residents in Pok Wai and nearby residential developments (R3), the magnitude of impacts in construction phase will be negligible due to the small scale and temporary nature of the fresh water trunk mains laying works.

10.8.1.5 During the night time, lighting provisions for the proposed works and the lighting glare emitted will cause adverse impact. Therefore, the lighting design of the proposed works shall be designed to minimise the glare at night.

Table 10.12 – Significance of Visual Impacts in the Construction & Operation Phases

VSR ID	Key VSR	Magnitude of Impact ^[2]		Receptor Sensitivity ^[3]		Impact Significance Threshold BEFORE Mitigation ^[4]		Recommended Mitigation Measures	Residual Impact Significance Threshold AFTER Mitigation ^[4]
		Construction	Operation	Construction	Operation	Construction	Operation		Construction	Operation^[5]
										DAY 1	YEAR 10
A1	Hikers at Ngau Tam Shan	S	N	H	H	SL	I	CM1-CM7	I	I	I
A2	Hikers at Kai Kung Leng	S	N	H	H	SL	I	CM1-CM7	I	I	I
R1	Residents in village of Yau Tam Mei Tsuen (II)	N	N	M	M	I	I	CM1-CM7	I	I	I
R2	Residents in Fuk Hing Lei and nearby residential developments	N	N	M	M	SL	I	CM1-CM7	I	I	I
R3	Residents in Pok Wai and nearby residential developments	N	N	M	M	I	I	N/A	I	I	I
Note: [1] All impacts are adverse unless otherwise noted with beneficial [2] Negligible (N) / Small (S) / Intermediate (I) / Large (L) [3] Low (L) / Medium (M) / High (H) [4] Insubstantial (I) / Slight (SL) / Moderate (M) / Substantial (S) [5] No mitigation measure is required during the operational phase.

10.9 Significance of Residual Landscape and Visual Impacts

10.9.1.1 With full implementation of the mitigation measures as detailed in Section 10.8, no significantly adverse residual impacts are anticipated from the construction of the Project. All the residual landscape and visual impacts arising from the project are considered acceptable.

10.9.1.2 The potential significance of visual impacts during construction phase, before and after mitigation, is provided in Table 10.12. This assessment follows the proposed methodology and assumes that the appropriate design measures incorporated in the development layout and the mitigation measures identified in Table 10.10 would be implemented and that the full effect of the soft landscape mitigation measures would be realised after 10 years.

10.9.1.3 Trees surveyed within the proposed works areas are primarily common species. There is no Registered OVT within the works areas. Meanwhile, a number of TPIs, including mature trees with DBH of 1m or more, as well as Aquilaria sinensis, which are tree species of conservation interest, are recorded in the broad-brush tree survey, but no TPI would be affected by the proposed works.

10.9.1.4 Based on individual and broad-brush tree surveys, it is estimated that 200-300 nos. of trees (excluding Leucaena leucocephala) will be affected by the proposed works. All affected trees are either exotic woodland plantation species or common native growth. Broad-brush tree surveys for the proposed works, including modification of Chamber G, and fresh water trunk mains laying works between NTM WTW and NTM FWPSR, and between Ching Yau Road and San Tam Road, have been carried out with the survey results enclosed in Appendices 10.1 to 10.3.

10.9.1.5 Tree compensation according to DEVB TC(W) No.4/2020 – Tree Preservation will be carried out. Trees will be compensated at a ratio of not less than 1:1 in terms of quantity of removed trees. The project proponent is committed to compensate for the loss of trees in not less than 1:1 ratio in terms of quantity, it is anticipated that compensatory trees will be in areas under WSD’s vegetation maintenance, subject to further review and discussion with WSD and other relevant government departments on the availability of land. The locations for compensatory tree planting will be provided in due course after agreement with WSD and other relevant government departments.

10.9.1.6 In accordance with DEVB TCW No. 4/2020, in principle, size of compensatory trees at their maturity should be appropriate to the location and function. For compensatory planting on slopes, the planting of whip trees as a woodland mix would be proposed.

10.9.1.7 The residual impact on Woodland/Natural Hillside Plantation (LR1), Plantation within NTM WTW (LR2), Agricultural Land (LR4), Roadside Plantation (LR5), Modified Watercourse (LR7), Agricultural Fish Pond (LR8), Upland and Hillside LCA (LCA1), River Channel LCA (LCA2), Urban Peripheral Village LCA (LCA3), Residential Urban Fringe LCA (LCA4) and Transportation Corridor LCA (LCA5) will be insubstantial during both construction and operational phases.

10.9.1.8 The overall residual impact on all LR and LCA are considered as acceptable with implementation of mitigation measures.

10.10 Conclusion

10.10.1.1 This landscape and visual baseline survey has been conducted in accordance with Appendix I of the EIA SB No. ESB- ESB-333/2020 issued on 14 September 2020 and with reference to the criteria and guidelines as stipulated in Annex 10 and 18 of EIAO-TM and EIAO Guidance Note No. 8/2010. 

10.10.1.2 The proposed modification of Chamber G located within the Lam Tsuen Country Park. The proposed fresh water trunk mains located within the CA and GB, in which falls within column 2 of the planning note, which implies that planning permission from the Town Planning Board is required.

10.10.1.3 The most affected LR and LCA are Woodland / Natural Hillside Plantation (LR1) and Upland and Hillside LCA (LCA1), which are anticipated to be slightly adverse during construction phase. Upon full implementation of all proposed mitigation measures, the residual impacts on all LRs and LCAs are anticipated to be insubstantial during construction phase. During operational phase, the residual impacts of all LRs and LCAs are also anticipated to be insubstantial.

10.10.1.4 The most affected VSRs are Hikers at Ngau Tam Shan (A1), Hikers at Kai Kung Leng (A2) and Residents in Fuk Hing Lei and nearby residential developments (R2), which are anticipated to be slightly adverse during construction phase. Upon full implementation of all proposed mitigation measures, the residual impacts on all VSRs are anticipated to be insubstantial during construction phase. During operational phase, the residual impacts of all VSRs are also anticipated to be insubstantial.

10.10.1.5 Based on individual and broad-brush tree surveys, it is estimated that 200-300 nos. of trees (excluding Leucaena leucocephala) will be affected by the proposed works. Most affected trees are either exotic woodland plantation species or common native growth. No TPI would be affected based on the individual and broad-brush tree surveys.

10.10.1.6 Tree compensation according to DEVB TC(W) No.4/2020 – Tree Preservation will be carried out. Trees will be compensated at a ratio of not less than 1:1 in terms of quantity of removed trees. The project proponent is committed to compensate for the loss of trees in not less than 1:1 ratio in terms of quantity, it is anticipated that compensatory trees will be in areas under WSD’s vegetation maintenance, subject to further review and discussion with WSD on the availability of land. The locations for compensatory tree planting will be provided in due course after agreement with WSD.

10.10.1.7 Tree species selected shall be compatible with surrounding existing vegetation. It is considered that there is no net loss of landscape resources in terms of trees upon full implementation of compensatory planting. Given the extent of the proposed modification of Chamber G and fresh water trunk mains laying works are relatively small in scale, with full implementation appropriate landscape and visual mitigation measures, it is considered that all residual landscape and visual impacts are acceptable with mitigation measures implemented during construction phase.

11 Impact on Cultural Heritage

11.1 Legislation, Standards and Guidelines

11.1.1.1 The relevant legislation, standards and guidelines related to cultural heritage impact assessment are identified, including but not limited to the following:

· Environmental Impact Assessment Ordinance (EIAO) (Cap. 499), Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM), Annexes 10 and 19;

· Antiquities and Monuments Ordinance (Cap. 53);

· Hong Kong Planning Standards and Guidelines (HKPSG);

· Requirements for Cultural Heritage Impact Assessment from Appendix J of the EIA Study Brief No. ESB-333/2020; and

· Guidelines for Cultural Heritage Impact Assessment.

11.1.2 Environmental Impact Assessment Ordinance (Cap. 499)

11.1.2.1 Annex 10 of the EIAO-TM outlines the criteria for assessment of impact on sites of cultural heritage. The general presumption is in favour of the protection and conservation of all sites of cultural heritage. In addition, adverse impacts on sites of cultural heritage shall be kept to the absolute minimum.

11.1.2.2 Annex 19 of the EIAO-TM outlines the approaches required in investigating and assessing the impacts on sites of cultural heritage. There is no quantitative standard in deciding the relative importance of these sites, but in general, sites of unique archaeological, historical or architectural value will be considered as highly significant. Preservation in totality is preferred. If, due to site constraints and other factors, only preservation in part is possible, this must be fully justified with alternative proposals or layout designs, which confirm the impracticability of total preservation.

11.1.3 Antiquities and Monuments Ordinance (Cap. 53)

11.1.3.1 The Antiquities and Monuments Ordinance (Cap. 53) (A&M Ordinance) provides statutory protection against the threat of development on declared monuments to enable their preservation for posterity. The A&M Ordinance also establishes the statutory procedures to be followed in making such a declaration.

11.1.3.2 Any person who discovers an antiquity, or supposed antiquity, is required to report the discovery to the Antiquities Authority.

11.1.4 Hong Kong Planning Standards and Guidelines (HKPSG)

11.1.4.1 The Chapter 10, Conservation, of the HKPSG provides general guidelines and measures for the conservation of historical buildings, sites of archaeological interest and other antiquities.

11.1.5 Requirements for Cultural Heritage Impact Assessment

11.1.5.1 Appendix J of the EIA Study Brief No. ESB-333/2020 provides requirements on conducting cultural heritage impact assessment.

11.1.6 Guidelines for Cultural Heritage Impact Assessment

11.1.6.1 The Guidelines for Cultural Heritage Impact Assessment (CHIA) provide guidelines to assist the understanding of requirements in assessing impact(s) on Site of Cultural Heritage.

11.2 Assessment Methodology

11.2.1.1 The assessment area for the CHIA was defined by a distance of 500m from the boundary of the Project area according to Clause 3.4.12.2 of the EIA Study Brief No. ESB-333/2020. The CHIA shall include a Built Heritage Impact Assessment (BHIA) and an Archaeological Impact Assessment (AIA) for the construction and operation of the Project (see Figure 11.1 for the cultural heritage assessment area (CHAA)). The CHIA comprises the following tasks:

11.2.2 Baseline Study

11.2.2.1 A desktop review was conducted based on best available information, relevant studies held by Government departments, public libraries and the Hong Kong Heritage Discovery Centre Reference Library to identify the cultural heritage items including declared monuments, proposed monuments, graded historic sites/ buildings/ structure, sites/ buildings/ structures in the new list of proposed grading items, sites of archaeological interest or Government historic sites identified by AMO within the CHAA. The reference is provided in Section 11.8 for Bibliography.

11.2.3 Built Heritage Survey

11.2.3.1 Built heritage survey was conducted based on desktop review[4], details are discussed in Section 11.3, Section 11.4 and Section 11.5.

11.2.4 Archaeological Survey

11.2.4.1 According to Clause 2 of Appendix J of the EIA Study Brief No. ESB-333/2020, the scope of AIA study presented in the Preliminary Cultural Heritage Desktop Review Report was submitted to the AMO and EPD prior to commencement of the assessment. It was concluded in the Report that archaeological survey is not required. Details are discussed in Section 11.4 and Section 11.5.

11.2.5 Impact Assessment

11.2.5.1 Based on the findings and analysis from Baseline Study, a CHIA including AIA and BHIA for the construction and operation of the Project was conducted to assess the direct and indirect impacts on the known and unknown built heritage items within the assessment area. Cultural heritage impact was identified, appropriate practicable mitigation measures and monitoring to avoid or keep the adverse impact to the minimum have been recommended. A checklist including all the affected sites of cultural heritage, impacts identified, recommended measures as well as the implementation agent and period are included in implementation schedule of the Environmental Monitoring and Auditing (EM&A). The CHIA was conducted according to Annexes 10 and 19 of the TM and the Requirements for CHIA in Appendix J of the EIA Study Brief No. ESB-333/2020.

11.3 Baseline Conditions

11.3.1 Topographical Background

11.3.1.1 The CHAA is situated in the northwest part of Hong Kong and northwest of New Territories in the rural area. The existing Chamber G is located to the southeast of Ngau Tam Mei Water Treatment Works (NTM WTW), its raw water tunnels and access tunnel to the NTM WTW are located within Lam Tsuen Country Park and CA. The proposed fresh water trunk mains of the Project will mainly run through rural areas, with a section starting from NTM WTW then go southwest towards the Ngau Tam Mei Fresh Water Primary Service Reservoir (NTM FWPSR), and another section between Ching Yau Road and San Tam Road. NTM Site of Archaeological Interest (SAI) is located around 390m to the proposed fresh water trunk mains. (see Figure 11.1).

11.3.2 Historical Background

11.3.2.1 The proposed alignment and works are mainly along roads, and near existing site boundaries of the NTM WTW and NTM FWPSR. A number of villages and historical villages including Ngau Tam Mei Village, San Wai Tsuen and Pok Wai are located within or near to the CHAA but the works are restricted to road network and raw water tunnel and are not expected to affect historical villages.

11.3.3 Built Heritage

11.3.3.1 Desktop review identified no declared or proposed monuments, graded historic sites/ buildings/ structures, sites/ buildings/ structures in the new list of proposed grading items, and Government historic sites identified by AMO within the proposed alignment of fresh water trunk main and modification of Chamber G area.

11.3.3.2 One grade 2 and seven grade 3 historic buildings are identified within the cultural heritage assessment area. They are listed in Table 11.1 and their locations are shown in Figure 11.1.

Table 11.1 – Identified Graded Historic Buildings within the CHAA

Site Code	Name	Grading	Approximate Distance from Alignment of Proposed Fresh Water Trunk Main (m)
1	No. 87 San Wai Tsuen, San Tin, Yuen Long, New Territories	Grade 3	460
2	No. 50 San Wai Tsuen, San Tin, Yuen Long, New Territories	Grade 3	400
3	No. 51 San Wai Tsuen, San Tin, Yuen Long, New Territories	Grade 3	400
4	No. 57 San Wai Tsuen, San Tin, Yuen Long, New Territories	Grade 2	350
5	Hon Lo, No. 61 San Wai Tsuen, San Tin, Yuen Long, New Territories	Grade 3	320
6	No. 62 San Wai Tsuen, San Tin, Yuen Long, New Territories	Grade 3	300
7	No. 70 San Wai Tsuen, San Tin, Yuen Long, New Territories	Grade 3	290
8	No. 71 San Wai Tsuen, San Tin, Yuen Long, New Territories	Grade 3	260

11.3.3.3 Besides, an identified item Yau Shing Mo Temple (Site Code 9), is identified and located 470m away from the alignment of the proposed fresh water trunk main. Its location is shown in Figure 11.1.

11.3.4 Geological Background

11.3.4.1 The solid geology of the CHAA consists of Mai Po Formation with silver grey to greenish grey phyllite with metasandstone and four layers of graphite schist; Tai Mo Shan Formation with feldspar and quartz crystals, with some dark green biotite, and lithic lapilli of pale sandstone; and Tai Lam Granite. The superficial deposit includes terraced alluvial and debris flow areas, marine muds and sands (reclaimed), Holocene alluvium. (CEDD, 2020). Details are shown in Figure 11.2.

11.3.5 Archaeological Background

11.3.5.1 There is one SAI, Ngau Tam Mei SAI, located within the CHAA. It is at a distance of 390m away from the proposed alignment (its location refers to Figure 11.1). In addition to the SAI, a number of previous archaeological excavation was conducted within the CHAA. The SAI and previous archaeological excavation are mapped on Figure 11.3.

Second Territory-Wide Archaeological Survey (Yuen Long District)

11.3.5.2 In 1997, the archaeological survey conducted for Yuen Long discovered Late Bronze Age (Warring State period) pottery within an area at San Hing Farm (AMO 1997:25). Subsequently, two seasons of archaeological investigation were initially conducted with the excavation of five trenches (T1 to T5), which was then followed by another two trenches (T6 and T7) (AMO 1999:5). The seven test pits are all situated within the current CHAA and a cultural layer was present in T1 and T2. The material findings were retrieved from the upper 50cm (AMO 1997:25).

Main Drainage Channels for Ngau Tam Mei Project, Phase II (AMO 1999)

11.3.5.3 In 1999, an archaeological investigation was conducted as part of the captioned project to further identify the extent of the SAI. The included initially twenty-two auger holes (A1 to A22) and one test pit (T1) was extended with an additional twelve auger holes (A1 to A12), and three other test pits (T1 to T3). The auger tests A12, A13, A21, A22 and A1 to A12 and test pits T1 to T3 fall within or lie very close to the current CHAA. Auger tests (A1 to A12) and three test pits (T1 and T2 and T3) revealed results similar to the 1997 excavations with a cultural layer below the cultivated topsoil, however, no tile fragments with net patterns decorations and cloth imprints were collected from the surface. The centre of the cultural deposit was suspected to be at the top of a hillock, in the vicinity of T3 (AMO 1999:6). No archaeological remains were identified outside San Hing Farm.

11.3.6 Archaeological Potential Evaluation

11.3.6.1 The key elements of the proposed works that may involve excavation work for the Project include the followings:

· Laying of fresh water trunk mains between NTM WTW and NTM FWPSR, and Ching Yau Road and San Tam Road; and

· Modification of the Chamber G.

11.3.6.2 Based on the archaeological review result presented above and the key elements that may involve excavation work for the Project, Table 11.2 evaluated the archaeological potential of each of the key elements.

Table 11.2 – Archaeological Potential Evaluation of Key Elements of the Project

Existing Condition and Geology (Figure 11.2)			Archaeological Potential Evaluation
Proposed Modification of Chamber G (Layout refers to Figure 1.1a)
- On hilly ground not favourable for human settlement - Geology Condition: JTM, Qd			The northern part of the modification work will involve installation of raw water tunnel adjacent to the existing access tunnel. Thus, the work will only impact on area without archaeological potential. The southern part of the modification work will involve construction of raw water tunnel with pipeline connecting Muk Wu branch; raw water pipeline connecting new raw water tunnel and Muk Wu Branch, raw water tunnel from Muk Wu Branch to Tai Po Tau branch and raw water tunnel from Tai Po Tau branch to Au Tau branch. This hilly area is unfavourable for human settlement and therefore considered to have no archaeological potential. Archaeological investigations were conducted in 1997 and 1999 (refer to Section 11.3.5) at a distance of about 1.2km away from the Chamber G, but no archaeological remains were identified.
Proposed Fresh Water Trunk Mains (see Figure 11.1)
- Along the road between NTMWTW and NTM FWPSR, and a section between Ching Yau Road and San Tam Road Geology Condition: Qa, Qd, Qpd, QHH, Cmp and JTM			The proposed work (including new fresh water trunk mains of diameter ranging from 1600mm from the road between NTMWTW and NTM FWPSR, and a section between Ching Yau Road and San Tam Road) will be within and along existing areas of disturbance, mainly roads, existing utilities and cut slopes which have no potential for archaeological materials, deposits or features.
Remarks:
Qa	- Alluvium	QHH		-Marine mud
Qd, Cmp	-Debris flow deposits	JTM		-Tai Mo Shan Formation, undivided
Qpa	-Terraced alluvium	Qpd		-Debris flow deposits

11.3.6.3 As presented in Table 11.2, the proposed modification of Chamber G and proposed fresh water trunk mains are located within or along existing road network, hilly area or other disturbed areas like existing utilities and cut slope, these areas are of no archaeological potential. Moreover, a number of archaeological investigations were conducted in the assessment area but no archaeological remains were identified. Thus, no archaeological survey is required.

11.4 Cultural Heritage Impact Assessment

11.4.1 Archaeological Impact Assessment

Construction Phase

11.4.1.1 No excavation works of the Project are proposed in or adjacent to the NTM SAI, therefore no adverse archaeological impact due to the proposed works is anticipated.

11.4.1.2 The proposed works of the Project are located within or along existing road network, hilly area or other disturbed areas like existing utilities and cut slope, these areas are of no archaeological potential. Moreover, a number of archaeological investigations were conducted in the assessment area but no archaeological remains were identified.

Operational Phase

11.4.1.3 No excavation works will be involved in operational phase of the Project, therefore no adverse archaeological impact is anticipated.

11.4.1.4 Modification of Chamber G and proposed fresh water trunk mains of the Project are located in area without archaeological potential as discussed above. No impact is anticipated.

11.4.2 Built Heritage Impact Assessment

Construction Phase

11.4.2.1 The proposed works for laying of fresh water trunk mains include open cut excavation which is expected to have depths between 3.0m and 4.5m, to allow sufficient space for pipe bedding, laying of the 1,600mm diameter trunk mains with a minimum 1m soil cover.

11.4.2.2 For modification of Chamber G, mined excavation with drill and break would be adopted for construction of raw water tunnel adjacent to the existing access tunnel.

11.4.2.3 Potential vibration impact to the built heritage items included eight graded historic buildings and an identified item (Yau Shing Mo Temple) identified in CHAA are expected to be minimal as they are at considerable distance from the alignment of proposed fresh water trunk main according to Table 11.1. Besides, the scale of proposed construction work for laying of fresh water trunk mains is relatively small that involve open cut excavations. Thus, no direct or indirect built heritage impact is anticipated.

Operational Phase

11.4.2.4 No potential vibration impact is anticipated from Chamber G and fresh water trunk mains in the operational phase, no direct or indirect built heritage impact is anticipated.

11.5 Mitigation Measures

11.5.1 Archaeological Mitigation Measures

11.5.1.1 As the NTM SAI will not be impacted by the Project, no mitigation measure is required.

11.5.1.2 No other archaeological resources and archaeological potential areas were identified within CHAA, thus no mitigation measure is required.

11.5.1.3 As a precautionary measure, the project proponent and his/her contractor are required to inform AMO immediately when any antiquities or supposed antiquities under the Antiquities and Monuments Ordinance (Cap. 53) are discovered during the course of works.

11.5.2 Built Heritage Mitigation Measures

11.5.2.1 As no direct and indirect impact on the built heritage items are identified, no mitigation measure is required.

11.5.3 Residual and Cumulative Impacts

11.5.3.1 No adverse residual cultural heritage impact is anticipated.

11.5.3.2 No cumulative cultural heritage impact is anticipated.

11.6 Environmental Monitoring & Audit (EM&A)

11.6.1 Archaeology

11.6.1.1 As a precautionary measure, the project proponent and his/her contractor are required to inform AMO immediately when any antiquities or supposed antiquities under the Antiquities and Monuments Ordinance (Cap. 53) are discovered during the course of works.

11.6.2 Built Heritage

11.6.2.1 As no direct and indirect impact on the built heritage items are identified, no EM&A is required.

11.7 Conclusion

11.7.1.1 One SAI, NTM SAI, is identified within the CHAA where no excavation works of the Project are proposed in or adjacent to the SAI, therefore no adverse archaeological impact due to the Project is anticipated and thus, no mitigation measure is required.

11.7.1.2 The proposed works are largely along existing road network, hilly area or other disturbed areas of no archaeological potential. A number of archaeological investigations were conducted within the assessment area in 1997 and 1999, but no archaeological materials, deposits or features were identified. No archaeological survey is therefore required.

11.7.1.3 As a precautionary measure, the project proponent and his/her contractor are required to inform AMO immediately when any antiquities or supposed antiquities under the A&M Ordinance (Cap. 53) are discovered during the course of works.

11.7.1.4 Desktop review identified no declared or proposed monuments and Government historic sites identified by AMO are located within the CHAA.

11.7.1.5 One grade 2 and seven grade 3 historic buildings are identified. Besides, an identified item is located within CHAA. Direct and indirect impact is not anticipated as they are outside the works area of the Project, while potential construction vibration impact is considered minimal due to the small scale of the proposed works of fresh water trunk mains and adequate separate distance between the proposed works and the built heritage items. No mitigation measure is required.

11.8 Bibliography

11.8.1 English

Binnies (2021). Agreement No. CE40/2018 (WS) Ngau Tam Mei Water Treatment Works Extension – Feasibility Study, for Water Services Department.

B.A.V. Peacock (1985). Report of the Hong Kong Archaeological Survey. (Unpublished)

AAL (2021). Contract No. PM03/2020 Built Heritage Survey in Yuen Long and Built Heritage Impact Assessment Report.

AMO (1998). Archaeological Investigation Report on the Proposed Development in
Yuen Long Areas 13 and 14

AMO (1999). Archaeological Investigation Report for the Main Drainage Channels for
Ngau Tam Mei Project, Phase II

Fung, Chi Ming (1996). Yuen Long Historical Relics and Monuments. Yuen Long District Board

Geotechnical Control Office (1988 and 1989). Hong Kong Geological Survey-
Yuen Long-Sheet 2 and San Tin- Sheet 2. Solid and Superficial Geology

11.8.2 Chinese

古物古蹟辦事處:《全港文物普查 1997 第一地區(元朗區)工作報告》
(Hong Kong: AMO Archive, No. YL9, 1997)

民政事務局, 古物古蹟辦事處:《元朗牛潭尾主渠道第二期工程考古調查工作報告》
(Hong Kong: AMO Archive, No. YL15, 1999)

11.8.3 Internet

Antiquities and Monuments Office (2023). Declared monuments in Hong Kong (as of 20 May 2022); [information on line]; available from https://www.amo.gov.hk/filemanager/amo/common/form/DM_Mon_List_e.pdf; access on 23 June 2023.]

Antiquities and Monuments Office (2023). Government Historic sites Identified by AMO (as at May 2022); [information on line]; available from https://www.amo.gov.hk/filemanager/amo/common/form/build_hia_government_historic_sites.pdf;
internet; access on 23 June 2023.

Antiquities and Monuments Office (2023). List of the 1444 Historic Buildings with Assessment Results (as at 9 March 2023); [information on line]; available from https://www.aab.gov.hk/filemanager/aab/en/content_29/AAB-SM-chi.pdf; access on 23 June 2023.]

Antiquities and Monuments Office (2023). List of new items for grading assessment with assessment results (as 1 June 2023); [information on line]; available from https://www.aab.gov.hk/filemanager/aab/en/content_29/list_new_items_assessed.pdf; access on 23 June 2023.]

Antiquities and Monuments Office (2023). List of Sites of Archaeological Interest in Hong Kong (as at Nov 2012) [information on line]; available from https://www.amo.gov.hk/filemanager/amo/common/form/list_archaeolog_site.pdf;
access on 23 June 2023.]

CEDD (2020). Lok Ma Chau Formation; available from:
https://www.cedd.gov.hk/eng/about-us/organisation/geo/pub_info/memoirs/ geology/vol/csl/index.html; access on 23 June 2023.]

12 Hazard to Life

12.1 Legislation, Standards and Guidelines

12.1.1 General

12.1.1.1 The relevant legislation and associated guidance applicable to the present study for the assessment of hazard to life include:

· Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM); and

· Dangerous Goods Ordinance (Cap. 295).

12.1.2 Technical Memorandum on Environmental Impact Assessment Process

12.1.2.1 As set out in Annex 4 of the EIAO-TM, the criterion for hazard to human life is to meet the Hong Kong Risk Guidelines (HKRG). The risk guidelines are expressed in terms of individual and societal risks as shown in Table 12.1 below.

Table 12.1 – Criteria for Individual and Societal Risks

Risk	Descriptions
Individual Risk	Maximum level of offsite individual risk should not exceed 1 in 100,000 per year i.e. 1x10^-5 per year.
Societal Risk	With the population increases, the societal risk will be increased. The societal RG is presented graphically in Appendix 12.1. It is expressed in terms of lines plotting the cumulative frequency (F) of N or more deaths in the population from incidents at the installation. Two F-N risk lines are used in the RG that demark “acceptable” or “unacceptable” societal risks. The intermediate region indicates the acceptability of societal risk is borderline and should be reduced to a level which is “as low as reasonably practicable” (ALARP). It seeks to ensure that all practicable and cost-effective measures that can reduce risk will be considered.

12.2 Hazard-to-life Impact Assessment

12.2.1 Identification of Hazard Scenarios Sources

12.2.1.1 As discussed in Section 1, the Project will mainly involve the construction of a 1km fresh water trunk main which encroach into boundary of the Conservation Area (CA), between Ngau Tam Mei Water Treatment Works (NTM WTW) and Ngau Tam Mei Fresh Water Primary Service Reservoir (NTM FWPSR), and Ching Yau Road and San Tam Road to the supply network and modification of Chamber G located near NTM WTW.

12.2.1.2 Currently, NTM WTW is classified as Potentially Hazardous Installations (PHIs) due to its on‑site liquid chlorine storage. The Consultation Zone (CZ) and Safety Buffer Zone (SBZ) of NTM WTW is 1km (excluding area 50m above it) and 250m respectively (Figure 12.1).

12.2.1.3 For the modification of Chamber G, as discussed in Section 2.5.7, mined excavation with drill and break method is chosen for the construction of the proposed access tunnels and bypass tunnels located underground. The use and transportation of explosives due to drill and blast method are not anticipated, and hence any potential safety risk is not anticipated. Hazard to life assessment for explosives is not required.

12.2.2 Evaluation of Hazard-to-life Impact

Potentially Hazardous Installation (PHI) (Liquid Chlorine Store)

12.2.2.1 According to the information provided by the Project Proponent (i.e. WSD), both On-Site Chlorine Generation (OSCG) and liquid chlorine are currently utilised in NTM WTW. Chlorine would be generated on-site on demand and on-site storage of chlorine would be no longer required upon depleting existing liquid chlorine. In addition, based on the information from Project Proponent, it is anticipated that there would not be any liquid chlorine remained in NTM WTW prior commencing construction of the Project. As such, there would be no liquid chlorine stored at the NTM WTW during both construction and operational phases. Associated risk with transportation and storage of liquid chlorine will be eliminated. As a result, the NTM WTW would not be considered as a PHI and is therefore expected to be delisted from the PHI Register prior to the commencement of construction works of the Project. The potential risk would be limited and a Quantitative Risk Assessment (QRA) regarding liquid chlorine storage is not required.

On-site Chlorine Generation (OSCG) Plant and Other Dangerous Goods (DG) Facilities at NTM WTW

12.2.2.2 OSCG plant would be adopted at NTM WTW to generate chlorine for disinfection of filtered water, which requires storage of chemicals associated with the OSCG process that are classified as DG. According to the Study Brief of this Project (ESB-333/2020), QRA of the OSCG plant and DG facilities is needed as NTM WTW was one of the project components. However, the aboveground works of this Project is about 300m away from the OSCG plant and DG facilities, impacts to them is not anticipated. Hence, the QRA regarding OSCG plant and DG facilities for this Project is not required.

Explosives

12.2.2.3 According to the Study Brief of this Project (ESB-333/2020), hazard assessment should be carried out if there is use of explosives for the construction activities and the storage or blasting location is in close proximity to populated areas and/or PHI site. Mined excavation with drill and break are chosen for the construction of the proposed tunnels located underground for the modification of Chamber G instead of drill and blast, so use of explosives would no longer be required for construction of this Project. Hence, the potential risk induced by them would be eliminated and a QRA regarding explosives is not required.

12.3 Conclusion

12.3.1.1 The PHI, NTM WTW, which currently stores and uses liquid chlorine on site is identified as a hazardous source in the vicinity of the Project. There would be no liquid chlorine storage at NTM WTW before the commencement of the construction works of this Project and explosives would not be used for the construction activities. The aboveground works (i.e. mainlaying of fresh water trunk mains) of this Project is about 300m away from the OSCG plant and DG facilities of NTM WTW, impacts to them is not anticipated. Therefore, no hazard-to-life impact would be induced.

13 Environmental Monitoring & Audit

13.1 Introduction

13.1.1.1 This section summarises the requirements on environmental monitoring and audits for the construction and operation of the Schedule 2 Designated Project (DP) item, i.e. proposed fresh water trunk mains and modification of Chamber G, based on the assessment results of various environmental issues. Details of the Environmental Monitoring and Audit (EM&A) programme can be referred to the separate EM&A Manual.

13.2 Project Organization

13.2.1.1 A project organisation consisting of the Engineer’s Representative (ER), Independent Environmental Checker (IEC), Environmental Team (ET), Project Proponent (i.e. WSD) and Contractor should be established to take on the responsibilities for environmental protection for the Project. The IEC will be appointed by the Project Proponent to conduct independent auditing on the overall EM&A programme including environmental and operation audit, implementation of mitigation measures, EM&A submissions, and any other submission required under the EP. ET is responsible for conducting the EM&A programme and to ensure the Contractor’s compliance with the environmental performance requirements. The organisation, responsibilities of respective parties and lines of communication with respect to environmental protection works are given in the EM&A Manual.

13.3 EM&A Manual

13.3.1.1 EM&A is an important aspect in the EIA process which specifies the timeframe and responsibilities for the implementation of environmental mitigation measures.

13.3.1.2 A project specific EM&A Manual to the Project has been prepared as part of the Environmental Impact Assessment Ordinance (EIAO) based on the latest design information available and EPD’s generic EM&A Manual. The project specific EM&A Manual highlights the following issues:

· Organisation, hierarchy and responsibilities of the Contractor, the Engineer or ER, ET and IEC with respect to the EM&A requirements during construction phase of the Project; 

· Information on project organisation and programming of construction activities for the Project;

· Requirements with respect to the construction schedule and necessary EM&A programme to track the varying environmental impacts;

· Procedure for undertaking on-site environmental audits;

· Requirements for reviewing pollution sources and working procedures required in the event of complaints;

· Requirements for reviewing the implementation of mitigation measures, and effectiveness of environmental protection and pollution control measures adopted; and

· Presentation of requirements for EM&A and appropriate reporting procedures.

13.3.1.3 The Contractor shall be requested to review and adhere to the mitigation measures and Environmental Mitigation Implementation Schedule (EMIS) with respect to the design developments and construction methodology. Any proposed changes to the mitigation measures shall be certified by the ET Leader and verified by the IEC as conforming to the relevant information and recommendations contained in the EIA Report.

13.4 Environmental Mitigation Implementation Schedule

13.4.1.1 An EMIS has been prepared alongside the EM&A of this EIA to summarise all the mitigation measures required to be implemented during the design, the construction and operational phases of the Project. The implementation responsibilities have also been identified in the EMIS. The EM&A Manual has also presented the requirements for environmental audit (e.g. audit frequency) throughout the construction and operational phases.

13.5 EM&A Programme

13.5.1 General

13.5.1.1 The Contractor will be requested to implement an environmental auditing programme throughout the Project and provide systematic procedures for auditing and minimising environmental impacts.

13.5.2 Air Quality

Construction Phase

13.5.2.1 With the implementation of the control measures, no adverse environmental impact is anticipated during the construction phase. Nevertheless, regular audit and site inspection at least once per week should be carried out during construction phase to ensure the control measures and good practices as recommended in this EIA Report and the EM&A Manual, are properly implemented by the Contractor.

Operational Phase

13.5.2.2 No adverse air quality impact during operational phase would be anticipated. Hence, environmental monitoring and audit is not required.

13.5.3 Noise

Construction Phase

13.5.3.1 With the implementation of noise control measures, no adverse environmental impact is anticipated during the construction phase. Nevertheless, the future Contractor shall prepare a Construction Noise Management Plan (CNMP) to review and assess the effectiveness of the noise mitigation measures quantitatively, and recommend the EM&A requirements if necessary. A regular audit and site inspection at least once per week should be carried out during construction phase to ensure that the construction noise levels will comply with the relevant criterion and the recommended best management practices as recommended in the CNMP and this EIA Report and EM&A Manual are properly implemented by the Contractor.

13.5.3.2 As the closest existing representative NSRs at Ngau Tam Village are located at more than 300m away from the modification works of Chamber G, adverse groundborne construction noise impacts from the modification of Chamber G are not anticipated. Hence, no groundborne construction noise monitoring is required.

Operational Phase

13.5.3.3 As discussed in Section 4.3, there are no planned fixed noise sources for the modification of Chamber G and the fresh water trunk mains. Hence, no adverse fixed noise sources impact is anticipated. In addition, the ventilation building of Chamber G would fall outside the boundary of CA and therefore will be addressed in a separate PER.

13.5.4 Water Quality

Construction Phase

13.5.4.1 With the implementation of good site practices and recommended mitigation measures to control construction site runoff, no adverse water quality impact is anticipated during the construction phase. Nevertheless, regular audit and site inspection at least once per week shall be carried out during construction phase to ensure that the recommended mitigation measures in this EIA Report and the EM&A Manual are properly implemented by the Contractor. Regular groundwater table should also be monitored during the modification works of Chamber G.

Operational Phase

13.5.4.2 No adverse water quality impact is anticipated during the operational phase. Hence, environmental monitoring and audit is not required.

13.5.5 Waste Management Implication

Construction Phase

13.5.5.1 During construction phase, the Contractor shall manage all generated waste in accordance with relevant legislation and guidelines. The recommended mitigation measures include good site practice, waste reduction measures as well as trip-ticket system.

13.5.5.2 Regular audit and site inspection should be carried out at least once per week to ensure proper waste management measures recommended in this EIA Report and EM&A Manual are implemented by the Contractor.

Operational Phase

13.5.5.3 As it is anticipated that no waste would be generated during the operational phase, monitoring and audit is not required.

13.5.6 Land Contamination

13.5.6.1 Based on desktop review findings, the information collected during the site surveys and from relevant government departments, no land contamination issue within the assessment area is anticipated. Environmental monitoring and audit is not required for both construction and operational phases.

13.5.7 Ecology

Construction Phase

13.5.7.1 The proposed works for proposed fresh water trunk mains and modification of Chamber G would cause minor loss of woodland, but it is not considered significant as all aboveground works will be located outside Lam Tsuen Country Park. No direct impacts on the aboveground habitats of Lam Tsuen Country Park will be resulted from the Project during construction phase. Indirect ecological impacts, i.e. disturbance to habitats and associated fauna adjacent to the Project including dust generation, waste dumping, glare, construction noise, water pollution, etc. would be mitigated by appropriate good site practices and mitigation measures. Regular audit and site inspection should be conducted at least once per week to ensure the recommended mitigation measures are properly implemented.

Operational Phase

13.5.7.2 No direct impacts on the aboveground habitats of Lam Tsuen Country Park will be resulted from the Project during operational phase. Indirect impacts during operational phase are considered to be negligible. No ecological monitoring and audit is necessary during the operation phase of the Project.

13.5.8 Fisheries

Construction Phase

13.5.8.1 No direct loss of active fishpond will be resulted from the Project. With the implementation of good site practises to control construction site runoff, no adverse impact on fisheries is anticipated during the construction phase, and thus monitoring and audit are not required.

Operational Phase

13.5.8.2 It is anticipated that there would be no impact on fisheries during operational phase, and thus monitoring and audits are not required.

13.5.9 Landscape and Visual

Construction Phase

13.5.9.1 Mitigation measures such as tree preservation, tree transplanting, regular inspection of retained trees, minimisation of light impact, etc., should be adopted during the construction phase. Regular audit and site inspection should be undertaken during the construction period to ensure that the mitigation measures recommended in this EIA Report and EM&A Manual are properly implemented by the Contractor.

Operational Phase

13.5.9.2 No visual change will be resulted during operational phase of the Project, mitigation measure as well as monitoring and audit are not required.

13.5.10 Cultural Heritage

Construction Phase

13.5.10.1 As the Ngau Tam Mei Site of Archaeological Interest (SAI) identified within the assessment area will not be impacted by the Project, mitigation measure as well as monitoring and audit are not required.

13.5.10.2 As a precautionary measure, Antiquities and Monument Office (AMO) should be informed immediately when any antiquities or supposed antiquities under the Antiquities and Monument Ordinance (Cap. 53) are discovered during the course of works.

13.5.10.3 No direct and indirect impact is identified and potential vibration impact is considered minimal for the built heritage items identified, and hence mitigation measure as well as monitoring and audit are not required.

Operational Phase

13.5.10.4 The archaeology and built heritage would not be affected by the operational phase of the Project. Hence, mitigation measure as well as monitoring and audit are not required.

13.5.11 Hazard to Life

Construction Phase

13.5.11.1 No potential risk would be anticipated during construction phase. Hence, mitigation measure as well as monitoring and audit are not required. The Contractor should also ensure that there is no liquid chlorine storage at NTM WTW before the commencement of construction works of the Project.

Operational Phase

13.5.11.2 No potential risk during operational phase is envisaged. Hence, mitigation measure as well as monitoring and audit are not required.

14 Summary of Environmental Outcomes

14.1 General

14.1.1.1 With reference to Section 1 and Section 2, environmental considerations have been the key considerations throughout the Project. Alternative options for designs and construction methodologies have been duly considered. Besides, all the options considered have ensured that environmental impacts could be avoided or minimised where practicable and mitigated by implementing suitable mitigation measures to fulfil all the statutory requirements. The technical assessment conducted (see Section 3 to Section 12) have demonstrated that all the statutory requirements in Environmental Impact Assessment Study Brief (EIA SB) (No.: ESB-333/2020) and Technical Memorandum on Environmental Impact Assessment Ordinance (EIAO-TM) regarding the Designated Project (DP) elements under the revised EIAO have been complied with.

14.1.1.2 The following sections summarise the approaches that have been adopted to either avoid or minimise various environmental impacts throughout the design process, and the associated environmental enhancements.

14.2 Environmentally Friendly Options Considered and Incorporated to Avoid and Minimise Environmental Impact

14.2.1.1 As described in Section 2.6, avoidance and minimisation of environmental impacts have been one of the key considerations throughout the entire project development and design. For those impacts that could not been avoided, due considerations have been given to minimise those impacts as much as practicable so that all the residual impacts would comply with the statutory requirements. A summary of these avoidance and minimisation approaches is given in Table 14.1.

Table 14.1 – Key design considerations and the associated environmental benefits

Design Approach	Key Design Considerations and the Associated Environmental Benefits
Avoidance of above ground works within Lam Tsuen Country Park (see details in Section 2.6.2)	- Mined excavation with drill and break methods proposed for modification works of underground Chamber G, avoid any direct impacts to Lam Tsuen Country Park
Minimisation of works within CA (see details in Section 2.6.3)	- Minimisation of works within CA regarding laying of fresh water trunk mains as the works would be mainly located along the existing access road or within water works reserve area / slope between NTM WTW and NTM FWPSR, and between Ching Yau Road and San Tam Road
Minimisation of air quality impacts during construction (see details in Section 2.6.4)	- Adopt construction programme and design, e.g. to conduct mainlaying works of proposed fresh water trunk mains in sub-sections and in small scale, to minimise the construction dust impact - Adopt mitigation measures for fugitive dust such as regular water spraying and covering exposed earth surface by tarpaulins as far as practicable, etc. - Avoid the use of exempted Non-Road Mobile Machines (NRMM) where practicable - Install dust filter at the portal exhaust at the entrance of the access tunnel
Minimisation of the risk of unauthorised filling activities (see details in Section 2.6.5)	- Adopt trip-ticket system to monitor the disposal of Construction and Demolition (C&D) materials - Provide warning signs to deter any illegal dumping activities - Proper management of the Contractors on land transport of C&D materials to minimise the risk of unauthorised filling activities

14.3 Estimated Population Protected from Various Environmental Impacts

14.3.1.1 The Project has been carefully designed to protect the populations from various environmental impacts. The protected populations include the following:

· Existing Air Sensitive Receivers (ASR) and Noise Sensitive Receivers (NSR) such as residential premises in Ngau Tam Mei, San Wai, etc., by implementation of good site practices during the construction phase of the Project.

14.4 Environmental Benefits of Environmental Protection Measures Recommended

14.4.1.1 Mitigation measures/ good site practices have been recommended to further reduce the environmental impacts due to the construction and operation of the Project. Key recommended mitigation measures/ good site practices/ enhancement measures and their associated benefits are summarised in Table 14.2.

Table 14.2 – Key recommended mitigation measures/ good site practices/ enhancement measures and their associated benefits

Aspect	Key Recommended Mitigation Measures/ Good Site Practices	Associated Benefits
Air Quality	- Implement regular watering system on exposed construction areas with dust emission and haul road - Avoid using exempted NRMM as much as practicable - Dust filter will be installed at the portal exhaust at the entrance of the access tunnel	- Protect ASRs by reducing air emissions
Noise	- Use of Quieter Construction Methods/ Equipment - Use of Quality Powered Mechanical Equipment (QPME) - Use of temporary noise barriers and noise enclosure to screen noise from relatively static Powered Mechanical Equipment (PME) - Alternative use of plant items within on worksite, wherever practicable	- Protect NSRs by reducing construction noise impact
Water Quality	- Follow Best Management Practices (BMPs) of mitigation measures in controlling water pollution and good site management as specified in the Professional Persons Environmental Consultative Committee (ProPECC) Practice Note (PN) 2/23 “Construction Site Drainage” and Environment, Transport and Works Bureau (ETWB) Technical Circular (Works) No. 5/2005 “Protection of natural streams/rivers from adverse impacts arising from construction works” - Ensure compliance of effluent water from the sterilised water mains with the discharge requirements stipulated in the Technical Memorandum on Waste Pollution Control Ordinance (WPCO) - Adopt proper grouting and groundwater monitoring measures to prevent accidental groundwater infiltration from excavation works	- Protect Water Sensitive Receivers (WSR) during construction and operational phases
Waste Management	- Adopt good waste management and control practices to avoid generation of excessive amount of waste materials - Employ waste collectors for disposal of general refuse to prevent potential nuisance caused by mistreating general refuse, such as windblown, vermin, water pollution and visual impact - Employ licensed chemical waste collectors for collecting chemical waste - Follow the designated land-based transportation routes for different types of wastes - Carry out on-site sorting of C&D material - Make provisions in the Contract documents to allow and promote the use of recycled aggregates where appropriate - Implement a trip-ticket system for each works contract in accordance with DEVB TCW No. 06/2010 to ensure that the disposal of C&D materials is properly documented and verified	- Minimise waste generation - Ensure proper handling of chemical waste - Ensure the C&D materials are disposed to the designated outlets
Land Contamination	- No mitigation measures required	- N/A
Ecology	- Follow good site practices as specified in ProPECC PN 2/23 and standard mitigation measures to control site runoff and other pollutants caused by construction activities - Implement mitigation measures regarding dust generation, waste dumping, glare and construction noise	- Minimise indirect impacts during construction phase
Fisheries	- Follow good site practices as specified in ProPECC PN 2/23 and standard mitigation measures to control site runoff and other pollutants caused by construction activities - Provide temporary traffic arrangements to maintain access to ponds during construction phase, where necessary	- Minimise indirect fisheries impact
Landscape and Visual	- Careful site planning and management - Careful design of slope works - Preserve existing trees, transplant and compensate unavoidably affected trees where practicable - Regular inspection of retained trees - Minimisation of light impact - Reinstatement of temporarily disturbed areas	- Minimise landscape and visual impact during construction phase
Cultural Heritage	- No mitigation measures required - Inform Antiquities and Monument Office (AMO) immediately when any antiquities or supposed antiquities under the Antiquities and Monuments Ordinance (Cap. 53) are discovered during the course of works as a precautionary measure	- No impact to cultural heritage anticipated
Hazard to Life	- No mitigation measures required - The Contractor should ensure that there is no liquid chlorine storage at NTM WTW before the commencement of the construction works of the Project.	- N/A
General	- Implement a comprehensive Environmental Auditing System throughout the entire construction period - Employ an Environmental Team (ET) and Independent Environmental Checker (IEC)	- Ensure compliance with all statutory requirements and those recommendations in the EIA

15 Conclusion

15.1 General

15.1.1.1 As discussed in Section 1.2, upon reviewing the Designated Project (DP) elements of the Study under Item Q.1 of Part I of Schedule 2 of the revised Environmental Impact Assessment Ordinance (EIAO), the EIA of the Study would only include Project elements that fall into DP elements (see Figure 1.1), which includes the following:

· Laying of about 1km (around 750m from Ngau Tam Mei Water Treatment Works (NTM WTW) to Ngau Tam Mei Fresh Water Primary Service Reservoir (NTM FWPSR) and around 250m from Ching Yau Road to San Tam Road) of fresh water trunk mains of diameter 1600mm, which encroach into boundary of the Conservation Area (CA), for delivery of the treated water from the expanded NTM WTW to the NTM FWPSR and from the FWPSR to the existing fresh water distribution system near Tan Kwai Tsuen; and

· Modification of the existing raw water tunnel junction (Chamber G) located near NTM WTW within Lam Tsuen Country Park and CA.

15.1.1.2 A separate Preliminary Environmental Review (PER) Report would be prepared to include the non-DP elements of the Study.

15.1.1.3 This EIA Report has been prepared in accordance with the requirements given in the Environmental Impact Assessment Study Brief (EIA SB) (No.: ESB-333/2020) and the Technical Memorandum on Environmental Impact Assessment Ordinance (EIAO-TM) regarding the DP elements under the revised EIAO. Environmental assessment of the potential environmental impacts associated with the construction and operation of the Project has been conducted. Environmental issues covered in this EIA include:

· Air quality impact;

· Noise impact;

· Water quality impact;

· Waste management implications;

· Land contamination;

· Ecological impact;

· Fisheries impact;

· Landscape and visual impacts;

· Impact on cultural heritage; and

· Hazard to Life.

15.1.1.4 This section summarises the assessment results of each technical aspect and concludes the acceptability of the overall environmental performance of the Project.

15.1.1.5 The key assessment assumptions, limitation of assessment methodologies and all related approach on assessment of different environmental aspects requiring agreements with EPD are given in Appendix 15.1.

15.1.1.6 A summary of environmental impacts identified in this EIA is provided in Appendix 15.2 and the conclusions of each technical aspect are described in the following sections.

15.2 Air Quality

Construction Phase

15.2.1.1 The air quality assessment studies the potential air quality impacts on Air Sensitive Receivers (ASRs) due to the construction of the Project.

15.2.1.2 Potential air quality impact would be generated from excavation and backfilling works during the construction phase of the Project. For the laying of fresh water trunk mains, the works would also be constructed by sections along the alignment in small scale so the air quality impact is anticipated to be short-term and localised. With the implementation of the mitigation measures as stipulated in the Air Pollution Control (Construction Dust) Regulation, control measures, including watering on exposed work sites with dust emission and good site practices, no adverse air quality impact during the construction phase is anticipated.

15.2.1.3 For the modification works for Chamber G, the construction of raw water tunnels / chambers would involve mined excavation with drill and break method respectively, which would be underground works under this Project. No adverse air quality impact is anticipated from the underground works with installation of dust filter system at the portal of the access tunnel to Chamber G.

Operational Phase

15.2.1.4 No adverse air quality impact is anticipated during the operational phase.

15.3 Noise

15.3.1.1 The noise assessment studies the potential noise impacts on Noise Sensitive Receivers (NSRs) due to the construction and operation of the Project.

Airborne Construction Noise

15.3.1.2 Noise arising from the construction activities of the Project would have unavoidable potential impact on the NSRs located in the vicinity of the works areas of the proposed fresh water trunk mains. Unmitigated construction noise levels at the representative NSRs are predicted, which are found to be within the range of 67 to 94dB(A).

15.3.1.3 Mitigation measures are recommended, including use of quieter construction methods/ equipment, good site practices, quieter plant, silencer, movable noise barrier, noise enclosure, acoustic mat and retractable noise barrier. With the recommended mitigation measures in place, noise levels at all the planned and/ or existing NSRs including residential premises could comply with the EIAO-TM daytime construction noise criterion.

Groundborne Construction Noise

15.3.1.4 The closest existing representative NSRs at Ngau Tam Village are located at more than 300m away from the modification works of Chamber G. Given the large separation distance, adverse groundborne construction noise impacts from the modification of Chamber G are not anticipated.

Fixed Noise Sources Impact

15.3.1.5 As discussed in Section 4.3, there are no planned fixed noise sources for the modification of Chamber G and the fresh water trunk mains. Hence, no adverse fixed noise sources impact is anticipated. In addition, the ventilation building of Chamber G would fall outside the boundary of CA and therefore will be addressed in a separate PER.

15.4 Water Quality

Construction Phase

15.4.1.1 The key water quality impact associated with the proposed fresh water trunk mains laying works and the modification of Chamber G could impact the water bodies through general construction activities, construction site run-off, sterilisation of water mains prior to commissioning, accidental spillage of chemicals, sewage effluent from construction workforce, and tunnelling and underground works. With proper implementation of the recommended mitigation measures, no adverse water quality impacts would be anticipated during construction phase.

Operational Phase

15.4.1.2 During operational phase of the Project, major sources of water quality impact include stormwater runoff from paved or developed area. Considering that the proposed works would only result in marginal increase in stormwater runoff, no adverse water quality impacts are expected.

15.5 Waste Management

Construction Phase

15.5.1.1 Potential waste management implications from the generation of waste during the construction phase have been evaluated. Measures, including the opportunity for on-site sorting, reusing C&D materials etc., are devised in the construction methodology to minimise the surplus materials to be disposed. Recommendations have been made for implementation by the Contractor during the construction period to minimise waste generation and off-site disposal.

Operational Phase

15.5.1.2 No waste generation is anticipated during the operational phase.

15.6 Land Contamination

15.6.1.1 Potentially contaminative land uses within the assessment area have been examined, as well as their potential impacts on future use. Based on desktop review findings, the information collected during the site surveys and from relevant government departments, no land contamination issues within the assessment area are anticipated, environmental site investigation (SI) works are not required. Preparation and submission of Contamination Assessment Plan (CAP), Remediation Action Plan (RAP) and Remediation Report (RR) are therefore not necessary.

15.6.1.2 No future works would be conducted within the assessment area (i.e. Chamber G and proposed fresh water trunk mains) before commencement of the Project while major construction works for the Project are anticipated to commence in Year 2025. Site re-appraisal is therefore not required prior to the commencement of the construction. No land contamination impacts are identified for the Project. No further site investigation and land contamination assessment are required for the Project.

15.7 Ecology

Construction Phase

15.7.1.1 Literature review and a 6-month ecological field survey covering both wet and dry seasons were undertaken to establish the ecological profile of the proposed works areas and assessment area. The proposed works areas are dominated by developed areas with low ecological value.

15.7.1.2 The proposed aboveground works would not encroach into the boundary of Lam Tsuen Country Park, hence no direct impact on wildlife and habitats within the Country Park is anticipated. Although small sections of the fresh water trunk mains from NTM WTW to NTM FWPSR, and from Ching Yau Road to San Tam Road would encroach into CA, the required works would be located along the existing access roads/ slope adjacent to existing access road. The associated construction works would be minor excavation, mainlaying and backfilling, therefore, no significant ecological impacts to the CA is anticipated.

15.7.1.3 The potential construction runoff and other disturbance impacts resulting from the proposed works, including impacts to the groundwater table, may potentially have indirect impact on wildlife and species of conservation interest. Nonetheless, the underground modification of Chamber G is located away from existing watercourses and waterbodies, as well as any species of conservation importance. In addition, mitigation measures such as good site practice and control of groundwater infiltration are proposed.

15.7.1.4 Overall, with the effective implementation of the recommended mitigation measures, no significant adverse residual ecological impacts during construction phase are expected from the Project.

Operational Phase

15.7.1.5 No direct impacts to habitats and species are anticipated during the operational phase of the Project. Indirect impacts are considered to be negligible.

15.8 Fisheries

Construction Phase

15.8.1.1 No direct loss of active fishpond results from the Project. Indirect impacts arising from the Project during the construction phase would be properly mitigated through standard practices and thus no significant fisheries impact is expected to occur.

Operational Phase

15.8.1.2 No fisheries impact during the operational phase of the Project have been identified. Operational phase indirect impacts are considered to be negligible.

15.9 Landscape and Visual

15.9.1.1 The Landscape Resources (LRs) and Landscape Character Areas (LCAs) as well as the Visual Sensitive Receivers (VSRs) within the visual envelope of the Project, were identified and assessed.

15.9.1.2 The most affected LR is Woodland / Natural Hillside Plantation and the most affected LCA is Upland and Hillside LCA. Upon full implementation of all proposed mitigation measures, the residual impacts on all LRs and LCAs are anticipated to be insubstantial during construction phase. During operational phase, the residual impacts of all LRs and LCAs are also anticipated to be insubstantial.

15.9.1.3 The most affected VSRs are Hikers at Ngau Tam Shan, Hikers at Kai Kung Leng and Residents in Fuk Hing Lei and nearby residential developments. Upon full implementation of all proposed mitigation measures, the residual impacts on all VSRs are anticipated to be insubstantial during construction phase. During operational phase, the residual impacts of all VSRs are also anticipated to be insubstantial. All the residual landscape and visual impacts arising from the Project are considered acceptable.

15.10 Cultural Heritage

Construction Phase

15.10.1.1 One Site of Archaeological Interest (SAI), NTM SAI, is identified within the assessment area where no excavation works of the Project will exist in or be adjacent to the SAI, therefore no adverse archaeological impact due to the Project is anticipated and thus, no mitigation measure is required.

15.10.1.2 The proposed works are largely along existing road network or other disturbed areas of no archaeological potential. A number of archaeological investigations were conducted within the assessment area in 1997 and 1999, but no archaeological materials, deposits or features were identified. No archaeological survey is therefore required.

15.10.1.3 As a precautionary measure, the project proponent and his/her contractor are required to inform Antiquities and Monuments Office (AMO) immediately when any antiquities or supposed antiquities under the Antiquities and Monuments Ordinance (Cap. 53) are discovered during the course of works.

15.10.1.4 Desktop review identified no declared or proposed monuments and Government historic sites identified by AMO are located within the assessment area.

15.10.1.5 One grade 2 and seven grade 3 historic buildings are identified. Besides, an identified item is located within the assessment area. Direct impact is not anticipated as they are outside the works area of the Project, while potential construction vibration impact is considered minimal due to the small scale of the proposed works of fresh water trunk mains and adequate separate distance between the proposed works and the built heritage items.

15.10.1.6 As no direct and indirect impact on the built heritage items are identified, no mitigation measure is required.

Operational Phase

15.10.1.7 No adverse archaeological / built heritage impact arising from operation of the Project is identified.

15.11 Hazard to life

15.11.1.1 The Potentially Hazardous Installation (PHI), NTM WTW, which currently stores and uses liquid chlorine on site is identified as a hazardous source in the vicinity of the Project. There would be no liquid chlorine storage at NTM WTW before the commencement of the construction works of this Project and explosives would not be used for the construction activities. The aboveground works (i.e. mainlaying of fresh water trunk mains) of this Project is about 300m away from the OSCG plant and DG facilities of NTM WTW, impacts to them is not anticipated. Therefore, no hazard-to-life impact would be induced.

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[1] Mitigation measures subject to change in development design.

[2] DEVB TC(W) No. 5/2020 – Registration and Preservation of Old and Valuable Trees.

[3] In accordance with DEVB TCW No. 04/2020, trees of particular interest are defined in paragraph 2.6.1 of the Guidelines for Tree Risk Assessment and Management Arrangement promulgated by the Development Bureau. Examples of trees of particular interest are listed as follows:

· OVTs and trees that are potentially registerable in the Register of OVTs;

· Trees of 100 years old or above;

· Trees with trunk diameter equal to or exceeding 1.0 m (measured at 1.3 m above ground level), or with height/canopy spread equal to or exceeding 25 m;

· Stonewall trees or trees of outstanding form (taking account of overall tree sizes, shape and any special features);

· Rare tree species listed in “Rare and Precious Plants of Hong Kong” published by Agriculture, Fisheries and Conservation Department;

· Endangered plant species protected under the Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586);

· Tree species listed in the Forestry Regulations (Cap. 96A) under the Forests and Countryside Ordinance (Cap. 96);

· Well-known Fung Shui trees;

· Landmark trees with evidential records to support the historical or cultural significance of the trees;

· Trees which may arouse widespread public concerns;

· Trees which may be subject to strong local objections on removal.

[4] WSP, 2022. Agreement No. CE80/2020(WS) Laying of Fresh Water Trunk Mains From The Ngau Tam Mei Fresh Water Primary Service Reservoir To Tan Kwai Tsuen - Investigation - Draft EIA Report Input, for Water Services Department