Figure 1.1	Locations of Key Construction Activities
Figure 2.1	Locations of Air and Noise Monitoring Stations and Chek Lap Kok Wind Station
Figure 2.2	Overall Sampling Grids for the Newly Reclaimed Area
Figure 2.3	The Backfilling Locations for Treated Marine Sediment
Figure 2.4	Vessel based Dolphin Monitoring Transects in Construction, Post-Construction and Operation Phases

Appendices

Appendix A	Contract Description
Appendix B	Project Organization Chart
Appendix C	Environmental Mitigation Implementation Schedule (EMIS) for Construction Phase
Appendix D	Monitoring Results
Appendix E	Chinese White Dolphin Monitoring Results
Appendix E.1	Voluntary Supplementary Surveys Results
Appendix F	Summary of Environmental Complaints and Cumulative Statistics on Exceedances, Notification of Summons, and Prosecution
Appendix G	Tree Schedule

Abbreviations

3RS	Three-Runway System
AAHK	Airport Authority Hong Kong
AECOM	AECOM Asia Company Limited
ACE	Advisory Council on the Environment
AFCD	Agriculture, Fisheries and Conservation Department
AIS	Automatic Identification System
ANI	Encounter Rate of Number of Dolphins
APM	Automated People Mover
AW	Airport West
BHS	Baggage Handling System
CAP	Contamination Assessment Plan
CAR	Contamination Assessment Report
CDS	Conventional Distance Sampling
CLGs	Community Liaison Groups
COVID	Coronavirus Disease
CWD	Chinese White Dolphin
CV	Coefficient of Variation
DCM	Deep Cement Mixing
DEZ	Dolphin Exclusion Zone
DPSE	Number of Dolphins per 100 Units of Survey Effort
EIA	Environmental Impact Assessment
EM&A	Environmental Monitoring & Audit
EP	Environmental Permit
EPD	Environmental Protection Department
EVT	Eastern Vehicular Tunnel
ET	Environmental Team
HDD	Horizontal Directional Drilling
HKIA	Hong Kong International Airport
HOKLAS	The Hong Kong Laboratory Accreditation Scheme
HSFs	High Speed Ferries
HZMB	Hong-Kong-Zhuhai-Macao Bridge
IEC	Independent Environmental Checker
LKC	Lung Kwu Chau
MCDS	Multiple Covariate Distance Sampling
MTCC	Marine Traffic Control Centre
MMHK	Mott MacDonald Hong Kong Limited
MMWP	Marine Mammal Watching Plan
MSS	Maritime Surveillance System
MTRMP-CAV	Marine Travel Routes and Management Plan for Construction and Associated Vessel
NEL	Northeast Lantau
NLMP	North Lantau Marine Park
NWL	Northwest Lantau
RBRGs	Risk Based Remediation Goals
SC	Sha Chau
SCLKCMP	Sha Chau and Lung Kwu Chau Marine Park
SCZ	Speed Control Zone
SPSE	Number of On-effort Sightings per 100 Units of Survey Effort
SPS-1	Sewage Pumping Station 1
STG	Encounter Rate of Number of Dolphin Sightings
SWL	Southwest Lantau
The Project	The Expansion of Hong Kong International Airport into a Three-Runway System
The SkyPier Plan	Marine Travel Routes and Management Plan for High Speed Ferries of SkyPier
T2	Terminal 2
T2C	Terminal 2 Concourse
TCLP	Toxicity Characteristics Leaching Procedure
TSP	Total Suspended Particulates
UCS	Unconfined Compressive Strength
WL	West Lantau
WMP	Waste Management Plan
WVT	Western Vehicular Tunnel

Executive summary

The “Expansion of Hong Kong International Airport into a Three-Runway System” (the Project) serves to meet the future air traffic demands at Hong Kong International Airport (HKIA). On 7 November 2014, the Environmental Impact Assessment (EIA) Report (Register No.: AEIAR-185/2014) for the Project was approved and an Environmental Permit (EP) (Permit No.: EP-489/2014) was issued for the construction and operation of the Project.

This is the 10^th Construction Phase Annual EM&A Report for the Project which summarizes the monitoring results and audit findings of the EM&A programme during the reporting period from 1 January 2025 to 31 December 2025.

The new North Runway was commissioned in November 2022. Following the completion of reconfiguration works on the Centre Runway, the Three-Runway System (3RS) was commissioned on 28 November 2024. The expanded Terminal 2 (T2) is being launched in phases, with the first phase of operation commenced on 23 September 2025.

Key Activities in the Reporting Period

Key activities of the Project carried out in the reporting period were related to the following contracts:

Reclamation Works:

Contract 3206 Main Reclamation Works

● Installation of precast units, scour apron, armour rocks and miscellaneous works at eastern seawall.

Airfield Works:

Contract 3305 Airfield Ground Lighting System

● Cable laying works;

● Hardware installation works; and

● Defects rectification.

Contract 3310 North Runway Modification Works

● Architectural, builder’s work and finishing (ABWF) works at ancillary buildings;

● Construction of stormwater drainage, pavement, and underground utilities works;

● Construction of vehicular tunnel;

● Reinforced concreting works;

● Falsework and formwork; and

● Drainage and watermain works.

Terminal 2 Concourse and Apron Works:

Contract 3404 Integrated Airport Control System

● System testing and maintenance.

Contract 3408 Third Runway Concourse and Apron Works

● Reinforced concrete, building services and ABWF;

● Cable laying and utilities works; and

● Pavement works; and Operation of concrete batching plant.

Terminal 2 Expansion:

Contract 3508 Terminal 2 Expansion Works

● Pier, deck, parapet and drainage construction;

● Drainage construction and utilities works;

● Roof works, construction of beams and columns;

● Link bridge, crossroad duct laying, and utilities works;

● Abutment construction;

● Electrical & mechanical (E&M) works and ABWF; and

● Hard landscape works.

Automated People Mover and Baggage Handling System:

Contract 3601 New Automated People Mover System (TRC Line)

● Guidebeam installation; and

● Cable containment and laying works.

Contract 3602 Existing APM System Modification Works

● Restoration of buffer stop and stinger;

● Car commissioning running tests;

● Platform screen door installation works; and

● Steel fixing and formwork to track plinth.

Contract 3603 3RS Baggage Handling System (BHS)

● IT cabling, steel works, conveyor, fire service and lighting system installation; and

● E&M component installation.

Airport Support Infrastructure:

Contract 3801 APM and BHS Tunnels on Existing Airport Island

● Drainage and backfilling works; and

● Road pavement works.

Contract 3802 APM and BHS Tunnels and Related Works

● Excavation, lateral supports and backfilling works;

● APM and BHS Tunnel, box culvert construction and superstructure works; and

● Reinforced concrete works and ABWF.

Contract 3804 East and Landside Fire Stations

● Superstructure works and ABWF; and

● E&M, unities and defect works.

Contract 3805 New Airport District Police Operational Base

● Pile cap and site formation works;

● Dog kennel construction;

● Construction of superstructure and drainage system; and

● Installation of fuel tank.

Construction Support:

Contract 3901A Concrete Batching Facility

● Operation of concrete batching plant and material conveyor belt.

Contract 3901B Concrete Batching Facility

● Operation of concrete batching plant and material conveyor belt; and

● Decommissioning of concrete batching plant.

Contract 3908 Quay Management Services

● Provision of services of site management and logistic control of 3RS quays; and

● Provision of flat top barge and vehicle delivery services between the launching point in Hong Kong and 3RS quays.

Contract 3913 Asphalt Batching Plant

● Operation of asphalt batching plant.

Utilities:

132kV Cable

● Cable laying and duct installation.

EM&A Activities Conducted in the Reporting Period

The EM&A programme was undertaken in accordance with the Manual. Summary of monitoring activities during this reporting period is presented as below:

Monitoring/ Audit Activities	Number of Sessions
Air Quality Monitoring	384
Noise Monitoring	208
Vessel line-transect Surveys for operation phase Chinese White Dolphin (CWD) Monitoring	24

Environmental auditing works, including weekly site inspections of construction works conducted by the ET and bi-weekly site inspections conducted by the Independent Environmental Checker (IEC), audit of SkyPier High Speed Ferries (HSFs), audit of construction and associated vessels, and Dolphin Exclusion Zone (DEZ) Plan, were conducted in the reporting period. Based on the information including ET’s observations, records of Maritime Surveillance System (MSS), and contractors’ site records, it is noted that the environmental pollution control and mitigation measures were properly implemented and the construction activities of the Project in the reporting period did not introduce adverse impact to the environment.

Summary Findings of the EM&A Programme

The monitoring works for construction dust, construction noise, construction waste, landscape & visual, and operation phase CWD monitoring were conducted during the reporting period in accordance with the Manual.

Monitoring results of construction dust, construction noise and construction waste did not trigger the corresponding Action and Limit Levels in the reporting period. No non-conformities were recorded for landscape & visual monitoring in the reporting period.

Following the full commissioning of the 3RS, the scale of active construction activities has been significantly reduced. A proposal to scale down the air quality and construction noise impact monitoring was submitted to EPD and subsequently approved by EPD on 31 December 2025. Starting from January 2026, monitoring stations AR1A and NM1A are retained to continue air quality and construction noise impact monitoring, respectively.

A 12-month operation phase CWD monitoring by vessels line-transect survey commenced in January 2025 and was completed in December 2025.

Summary Table

The key findings of the EM&A programme during the reporting period are summarised as below:

	Yes	No	Details	Analysis / Recommendation / Remedial Actions
Breach of Limit Level^		√	No exceedances of project-related Limit Level were recorded.	Nil
Breach of Action Level^		√	No exceedances of project-related Limit Level were recorded.	Nil.
Complaints Received	√		Three complaints were received in 2025: 14 Jan, 25 Apr and 7 Aug 2025.	The complaint investigations were carried out in accordance with the Complaint Management Plan. Details are presented in Section 3.2.1.
Notification of any summons and status of prosecutions		√	No notification of summons nor prosecution was received.	Nil
Changes that affect the EM&A		√	There was no change to the construction works that may affect the EM&A.	Nil

Remarks: ^ Only triggering of Action or Limit Level found related to Project works is counted as Breach of Action or Limit Level.

1 Introduction

1.1 Background

On 7 November 2014, the Environmental Impact Assessment (EIA) Report (Register No.: AEIAR-185/2014) for the “Expansion of Hong Kong International Airport into a Three-Runway System” (the Project) was approved and an Environmental Permit (EP) (Permit No.: EP-489/2014) was issued for the construction and operation of the Project.

Airport Authority Hong Kong (AAHK) commissioned Mott MacDonald Hong Kong Limited (MMHK) to undertake the role of Environmental Team (ET) for carrying out the Environmental Monitoring & Audit (EM&A) works during the construction phase of the Project in accordance with the Manual [1] submitted under EP Condition 3.1. AECOM Asia Company Limited (AECOM) was employed by AAHK as the Independent Environmental Checker (IEC) for the Project.

The Project covers the expansion of the existing airport into a Three-Runway System (3RS) with key project components comprising land formation of about 650 hectares and all associated facilities and infrastructure including taxiways, aprons, aircraft stands, a passenger concourse, an expanded Terminal 2, all related airside and landside works and associated ancillary and supporting facilities. The submarine aviation fuel pipelines and submarine power cables also require diversion as part of the works.

Construction of the Project is to proceed in the general order of diversion of the submarine aviation fuel pipelines, diversion of the submarine power cables, land formation, and construction of infrastructure, followed by construction of superstructures.

The summary of construction works programme can be referred to the corresponding Monthly EM&A Reports. Description of relevant contracts in the reporting period is presented in Appendix A.

1.2 Scope of this Report

This is the 10^th Construction Phase Annual EM&A Report for the Project which summarizes the key findings of the EM&A programme during the reporting period from 1 January 2025 to 31 December 2025.

1.3 Project Organization

The Project’s organization structure and the contact details of the key personnel are provided in Appendix B and Table 1.1 respectively.

Table 1.1: Contact Information of Key Personnel

Party	Position	Name	Telephone
Project Manager’s Representative (Airport Authority Hong Kong)	Principal Manager, Environmental Compliance, Sustainability	Lawrence Tsui	2183 2734
Environmental Team (ET) (Mott MacDonald Hong Kong Limited)	Environmental Team Leader	Terence Kong	2828 5919
Environmental Team (ET) (Mott MacDonald Hong Kong Limited)	Deputy Environmental Team Leader	Ken Wong	2828 5817
Independent Environmental Checker (IEC) (AECOM Asia Company Limited)	Independent Environmental Checker	Roy Man	3729 0380
	Deputy Independent Environmental Checker	Jackel Law	3856 5312

Reclamation Works:

Party	Position	Name	Telephone
Contract 3206 Main Reclamation Works (ZHEC-CCCC-CDC Joint Venture)	Project Manager	Alan Mong	3763 1352
Environmental Officer	Zhang Bin Wang	3763 1451

Party

Position

Name

Telephone

Contract 3206 Main Reclamation Works

(ZHEC-CCCC-CDC Joint Venture)

Project Manager

Alan Mong

3763 1352

Environmental Officer

Zhang Bin Wang

3763 1451

Airfield Works:

Party	Position	Name	Telephone
Contract 3305 Airfield Ground Lighting System (ADB Safegate Hong Kong Limited)	Project Manager	Allam Al-Turk	2944 9725
	Environmental Officer	Ivan Ting	9222 9490
Contract 3310 North Runway Modification Works (China State Construction Engineering (Hong Kong) Ltd.)	Project Manager	Terry Chow	6031 0887
	Environmental Officer	Federick Wong	9842 2703

Terminal 2 Concourse and Apron Works:

Party	Position	Name	Telephone
Contract 3404 Integrated Airport Control System (Shun Hing Systems Integration Co., Ltd.)	Project Manager	Andy Ng	9102 2739
	Environmental Officer	Michael Lo	6228 3926
Contract 3405 Third Runway Concourse Foundation and Substructure Works (China Road and Bridge Corporation – Bachy Soletanche Group Limited – LT Sambo Co., Ltd. Joint Venture)	Project Manager	Francis Choi	9423 3469
	Environmental Officer	Jacky Lai	9028 8975
Contract 3408 Third Runway Concourse and Apron Works (Beijing Urban Construction Group Company Limited and Chevalier (Construction) Company Limited Joint Venture)	Senior HSE Manager	Qian Zhang	5377 7976
	Environmental Officer	Ivan Mak	9422 4805

Terminal 2 Expansion:

Party	Position	Name	Telephone
Contract 3508 Terminal 2 Expansion Works (Gammon Engineering & Construction Company Limited)	Project Manager	Richard Ellis	6201 5637
Environmental Officer	Carrie Kwan	9276 0551

Party

Position

Name

Telephone

Contract 3508 Terminal 2

Expansion Works

(Gammon Engineering &

Construction Company

Limited)

Project Manager

Richard Ellis

6201 5637

Environmental Officer

Carrie Kwan

9276 0551

Automated People Mover and Baggage Handling System:

Party	Position	Name	Telephone
Contract 3601 New Automated People Mover System (TRC Line) (CRRC Puzhen Bombardier Transportation Systems Limited and CRRC Nanjing Puzhen Co., Ltd. Joint Venture)	Project Manager	Hongdan Wei	158 6180 9450
	Environmental Officer	H Y Yue	9185 8186
Contract 3602 Existing APM System Modification Works (Niigata Transys Co., Ltd.)	Project Manager	Xia Bo	6586 4950
	Environmental Officer	Y M Tong	5316 9801
Contract 3603 3RS Baggage Handling System (VISH Consortium)	Project Manager	K C Ho	9272 9626
	Environmental Officer	Richard Ng	9802 9577

Airport Support Infrastructure:

Party	Position	Name	Telephone
Contract 3801 APM and BHS Tunnels on Existing Airport Island (China State Construction Engineering (Hong Kong) Ltd.)	Contractor Representative	Ivan Lai	9507 6464
Contract 3802 APM and BHS Tunnels and Related Works (Gammon Engineering & Construction Company Limited)	Project Manager	John Adams	6111 6989
	Environmental Officer	Yan Ng	5345 8555
Contract 3804 East and Landside Fire Stations (Beijing Urban Construction Group Company Limited - Beijing Urban Construction International Company Limited - Kin Shing (Leung's) General Contractors Ltd Joint Venture)	Project Manager	Zhang Jinyuan	6708 0506
	Environmental Representative	Karis Lam	6084 9745
Contract 3805 New Airport District Police Operational Base (Chinney Construction Co., Ltd.)	Project Manager	Peter Li	9628 0768
	Environmental Officer	Mike Li	6306 8547

Construction Support:

Party	Position	Name	Telephone
Contract 3721 Construction Support Infrastructure Works (China State Construction Engineering (Hong Kong) Ltd.)	Senior Project Manager	Thomas Lui	9011 5340
	Environmental Officer	John Mak	6273 8703
Contract 3728 Minor Site Works (Shun Yuen Construction Company Limited)	Contract Manager	C K Liu	9194 8739
	Environmental Officer	Dan Leung	6856 5899
Contract 3733 Emergency Repair Service (Wing Hing Construction Co., Ltd.)	Project Manager	Michael Kan	9206 0550
	Health Safety Environmental Manager	Mike Leung	6625 2550
Contract 3901A Concrete Batching Facility (K. Wah Concrete Company Limited)	Project Manager	Benedict Wong	9553 2806
	Environmental Officer	C P Fung	9874 2872
Contract 3901B Concrete Batching Facility (Gammon Construction Limited)	General Manager	Gabriel Chan	2435 3260
	Environmental Officer	Rex Wong	2695 6319
Contract 3913 Asphalt Batching Plant (SPR Joint Venture)	Project Manager	Xie Yi Sheng	6580 6005
Contract 3913 Asphalt Batching Plant (SPR Joint Venture)	Environmental Officer	Kenneth Chan	9300 2182

Utilities:

Party	Position	Name	Telephone
132kV Cable (CLP Power Hong Kong Limited / Kum Shing (K.F.) Construction Company Limited)	Engineer	Ken Fung	6391 9087
Works Supervisor	Bosco Leung	6370 0780

Party

Position

Name

Telephone

132kV Cable

(CLP Power Hong Kong Limited / Kum Shing (K.F.) Construction Company Limited)

Engineer

Ken Fung

6391 9087

Works Supervisor

Bosco Leung

6370 0780

1.4 Contact Information for the Project

The contact information for the Project is provided in Table 1.2. The public can contact us through the following channels if they have any queries and comments on the environmental monitoring data and project related information.

Table 1.2: Contact Information of the Project

Channels	Contact Information
Hotline	3908 0354
Email	env@3rsproject.com
Fax	3747 6050
Postal Address	Airport Authority Hong Kong HKIA Tower 1 Sky Plaza Road Hong Kong International Airport Lantau Hong Kong Attn: Environmental Team Leader Mr Terence Kong c/o Mr Lawrence Tsui

1.5 Summary of Construction Works

During the reporting period, the expanded Terminal 2 (T2) was launched in phases, with the first phase of operation commenced on 23 September 2025. This phase involved the opening of the indoor Coach Hall, which provides 41 parking spaces for tour buses, cross boundary coaches, limousines, and resident coaches.

The key activities of the Project carried out in the reporting period are located in reclamation areas and existing airport island respectively. Works in the reclamation areas included rock armour laying works, filling, pavement works, Terminal 2 concourse superstructure works, tunnel works for Automated People Mover (APM) and Baggage Handling System (BHS) and associated works. Meanwhile, works on existing airport island involved mainly Terminal 2 expansion works, modification and tunnel works for APM and BHS, utilities works, road and drainage works, excavation works and 132kV cable laying works.

The locations of the key construction activities are presented in Figure 1.1.

1.6 Summary of EM&A Programme Requirements

The status for all environmental aspects is presented in Table 1.3.

Table 1.3: Summary of Status for All Environmental Aspects under the Manual

Parameters	EM&A Requirements	Status
Air Quality
Baseline Monitoring	At least 14 consecutive days before commencement of construction work	The baseline air quality monitoring results were reported in Baseline Monitoring Report and submitted to EPD under EP Condition 3.4.
Impact Monitoring	At least 3 times every 6 days	On-going
Noise
Baseline Monitoring	Daily for a period of at least two weeks prior to the commencement of construction works	The baseline noise monitoring results were reported in Baseline Monitoring Report and submitted to EPD under EP Condition 3.4.
Impact Monitoring	Weekly	On-going
Water Quality
General Baseline Water Quality Monitoring for reclamation, water jetting and field joint works	Three days per week, at mid-flood and mid-ebb tides, for at least four weeks prior to the commencement of marine works.	The baseline water quality monitoring results were reported in Baseline Water Quality Monitoring Report and submitted to EPD under EP Condition 3.4.
General Impact Water Quality Monitoring for reclamation, water jetting and field joint works	Three days per week, at mid-flood and mid-ebb tides.	General impact water quality monitoring for water jetting works was completed on 23 May 2017. The general impact water quality monitoring was terminated after 31 October 2023.
Initial Intensive Deep Cement Mixing (DCM) Water Quality Monitoring	At least four weeks	The Initial Intensive DCM Monitoring Report was submitted and approved by EPD in accordance with the Detailed Plan on DCM.
Regular DCM Water Quality Monitoring	Three times per week until completion of DCM works.	Due to the completion of all marine-based DCM works within April 2022, regular DCM monitoring was ceased at all monitoring stations starting from 28 April 2022.
Post-construction Phase Water Quality Monitoring	Three days per week, at mid-flood and mid-ebb tides for four weeks	The four-week post-construction phase water quality monitoring exercise was commenced on 14 November 2023 and completed on 9 December 2023.
Sewerage and Sewage Treatment
Methodology for carrying out annual sewage flow monitoring for concerned gravity sewer	Methodology to be prepared and submitted to EPD at least one year before commencement of the operation of 3RS	The proposed methodology for the annual sewage flow monitoring was approved by EPD. The annual flow monitoring commenced from June 2021 and was concluded in December 2022.
Details of the routine H₂S monitoring system for the sewerage system of 3RS	Details to be prepared and submitted to EPD at least one year before commencement of the operation of 3RS	Details of the routine H₂S monitoring system for sewerage systems of 3RS was approved by EPD. The H₂S monitoring is on-going.
Waste Management
Waste Monitoring	At least weekly	On-going
Land Contamination
Supplementary Contamination Assessment Plan (CAP)	At least 3 months before commencement of any soil remediation works.	The Supplementary CAP was submitted and approved by EPD pursuant to EP condition 2.20.
Site Re-appraisal Summary Report for Fire Training Facility	Site Re-appraisal Summary Report for Fire Training Facility	Site Re-appraisal Summary Report for Fire Training Facility was submitted and accepted by EPD.
Contamination Assessment Report (CAR)	CAR to be submitted for golf course	The CAR for Golf Course was submitted and accepted by EPD.
Contamination Assessment Report (CAR)	CAR to be submitted for Terminal 2 Emergency Power Supply Systems	The CARs for Terminal 2 Emergency Power Supply Systems were submitted and accepted by EPD.
Terrestrial Ecology
Pre-construction Egretry Survey Plan	Once per month in the breeding season between April and July, prior to the commencement of HDD drilling works.	The revised Egretry Survey Plan was submitted and approved by EPD under EP Condition 2.14.
Ecological Monitoring	Monthly monitoring during the HDD construction works period from August to March.	The terrestrial ecological monitoring at Sheung Sha Chau was completed in January 2019.
Marine Ecology
Pre-Construction Phase Coral Dive Survey	Prior to marine construction works	The Coral Translocation Plan was submitted and approved by EPD under EP Condition 2.12.
Coral Translocation	-	The coral translocation was completed on 5 January 2017.
Coral Post-translocation Monitoring	As per an enhanced monitoring programme based on the Coral Translocation Plan	The post-translocation monitoring programme according to the Coral Translocation Plan was completed in April 2018.
Chinese White Dolphins (CWD)
Baseline Monitoring	6 months of baseline surveys before the commencement of land formation related construction works. Vessel line transect surveys: Two full surveys per month; Land-based theodolite tracking surveys: Two days per month at the Sha Chau station and two days per month at the Lung Kwu Chau station; and Passive Acoustic Monitoring (PAM): For the whole duration of baseline period.	Baseline CWD results were reported in the CWD Baseline Monitoring Report and submitted to EPD in accordance with EP Condition 3.4.
Impact Monitoring	Vessel line transect surveys: Two full surveys per month; Land-based theodolite tracking surveys: One day per month at the Sha Chau station and one day per month at the Lung Kwu Chau station; and PAM: For the whole duration for land formation related construction works.	The construction phase CWD monitoring was completed in December 2023.
Post-construction Phase Monitoring	12 months of post monitoring upon the completion of marine construction works; and Vessel line transect survey: Two full surveys per month.	Post-construction phase CWD monitoring was completed in December 2024.
Operation Phase Monitoring	12 months of operation phase CWD monitoring upon full implementation of North Lantau Marine Park. Vessel line transect survey: Two full surveys per month.	Operation phase CWD monitoring was completed in December 2025.
Operation Phase Audit	SkyPier High Speed Ferries (HSFs) implementation measures: Once every three months for a period of one year upon operation of 3RS. Spill Response Plan implementation measures: Once every six months for a period of one year upon operation of 3RS.	Quarterly audits were conducted for one year following 3RS operation. The 4th audit was completed in November 2025, thereby completing the one-year audit programme. Half-yearly audits were conducted for one year following 3RS operation. The 2nd audit was completed in November 2025, thereby completing the one-year audit programme.
Landscape and Visual
Landscape and Visual Plan	At least 3 months before the commencement of construction works on the formed land of the Project.	The Landscape & Visual Plan was submitted to EPD under EP Condition 2.18.
Baseline Monitoring	One-off survey within the Project site boundary prior to commencement of any construction works	The baseline landscape & visual monitoring result has been reported in Baseline Monitoring Report and submitted to EPD under EP Condition 3.4.
Impact Monitoring	Weekly	On-going
Establishment Works Monitoring	Bi-monthly	On-going
Long Term Management (10 years) monitoring	Annually	On-going
Environmental Auditing
Regular site inspection	Weekly	On-going
Marine Mammal Watching Plan (MMWP) implementation measures	Monitor and check	Marine Mammal Watching Plan (MMWP) implementation measures were conducted from May to September 2025.
Dolphin Exclusion Zone (DEZ) Plan implementation measures	Monitor and check	Dolphin Exclusion Zone (DEZ) Plan implementation measures were conducted from May to December 2025.
SkyPier High Speed Ferries (HSFs) implementation measures	Monitor and check	On-going
Construction and Associated Vessels implementation measures	Monitor and check	On-going
Complaint Hotline and Email channel	Construction phase	On-going
Environmental Log-book	Construction phase	On-going
Silt Curtain Deployment Plan implementation measures	Monitor and check	All monitoring required under the Silt Curtain Deployment Plan was completed on 17 March 2025.
Spill Response Plan implementation measures	Monitor and check	On-going

Considering the nature of construction activities during the reporting period, impact monitoring was undertaken for air quality, noise, waste management, and landscape and visual. In addition, operation phase CWD monitoring was also carried out.

The EM&A programme also involved weekly site inspections and related auditing conducted by the ET for checking the implementation of the required environmental mitigation measures as recommended in the approved EIA Report. To promote the environmental awareness and enhance the environmental performance of the contractors, environmental trainings, and regular environmental management meetings were conducted during the reporting period which are summarized as below:

● 1 skipper training provided by ET; and

● 145 environmental management meetings for EM&A review with works contracts.

The EM&A programme has been undertaken in accordance with the recommendations presented in the approved EIA Report and the Manual. A summary of implementation status of the environmental mitigation measures for the construction phase of the Project during the reporting period is provided in Appendix C.

2 Environmental Monitoring and Auditing

2.1 Air Quality Monitoring

Impact 1-hour Total Suspended Particulates (TSP) monitoring was conducted three times every six days at two representative monitoring stations during the reporting period. The locations of the monitoring stations are described in Table 2.1 and presented in Figure 2.1.

Following the full commissioning of the 3RS, the scale of active construction activities has been significantly reduced. A proposal to scale down the air quality monitoring was submitted to EPD and subsequently approved by EPD on 31 December 2025. Starting from January 2026, monitoring station AR2 was terminated and only AR1A has been retained to continue air quality monitoring.

2.1.1 Action and Limit Levels

The Action and Limit Levels of the air quality monitoring stipulated in the EM&A programme for triggering the relevant investigation and follow-up procedures under the programme are provided in Table 2.1.

Table 2.1: Impact Air Quality Monitoring Stations

Monitoring Station	Location	Action Level (mg/m³)	Limit Level (mg/m³)
AR1A	Man Tung Road Park	306	500
AR2	Village House at Tin Sum	298	500

2.1.2 Monitoring Results

The graphical plots of impact air quality monitoring results during the reporting period are presented in Appendix D. Percentage of monitoring results within their corresponding Action and Limit Levels in the reporting period are presented in Table 2.2.

Table 2.2: Percentage of Air Quality Monitoring Results within Action and Limit Levels

	AR1A	AR2
Jan 2025	100%	100%
Feb 2025	100%	100%
Mar 2025	100%	100%
Apr 2025	100%	100%
May 2025	100%	100%
Jun 2025	100%	100%
Jul 2025	100%	100%
Aug 2025	100%	100%
Sep 2025	100%	100%
Oct 2025	100%	100%
Nov 2025	100%	100%
Dec 2025	100%	100%
Overall	100%	100%
Note: The percentages are calculated by dividing the number of monitoring results within their corresponding Action and Limit Level by the total number of monitoring results.

All monitoring results at AR1A and AR2 were within their corresponding Action and Limit Levels.

General meteorological conditions throughout the impact monitoring period were recorded and are summarized in Table 2.3.

Table 2.3: General Meteorological Condition during Impact Air Quality Monitoring

	Weather	Wind Direction
Jan – Mar 2025	Sunny to Cloudy	Northwest to Southwest
Apr – Jun 2025	Sunny to Drizzle	Northwest to Southeast
Jul – Sep 2025	Sunny to Cloudy	Northwest to Southeast
Oct – Dec 2025	Sunny to Cloudy	Northwest to East

2.1.3 Conclusion

No dust emission sources were observed at the monitoring stations during the monitoring sessions. As the sensitive receivers were far away from the construction activities, with the implementation of dust control measures, there was no adverse impact at the sensitive receivers attributable to the works of the Project.

2.2 Noise Monitoring

Impact noise monitoring was conducted at four representative monitoring stations once per week during 0700 and 1900 in the reporting period. The locations of monitoring stations are described in Table 2.4 and presented in Figure 2.1.

Following the full commissioning of the 3RS, the scale of active construction activities has been significantly reduced. A proposal to scale down the construction noise impact monitoring was submitted to EPD and subsequently approved by EPD on 31 December 2025. Starting from January 2026, monitoring stations NM2, NM3A, NM4, NM5 and NM6 were terminated and only NM1A has been retained to continue construction noise impact monitoring.

2.2.1 Action and Limit Levels

The Action and Limit levels of the noise monitoring stipulated in the EM&A programme for triggering the relevant investigation and follow-up procedures under the programme are provided in Table 2.4.

Table 2.4: Impact Noise Monitoring Stations

Monitoring Station	Location	Action Level	Limit Level, L_eq(30mins)dB(A)
NM1A	Man Tung Road Park	When one documented complaint is received from any one of the sensitive receivers	75 dB(A)
NM4	Ching Chung Hau Po Woon Primary School		65dB(A) / 70 dB(A) ⁽ⁱ⁾
NM5	Village House in Tin Sum		75 dB(A)
NM6	House No. 1, Sha Lo Wan		75 dB(A)
Notes: (i) The Limit Level for NM4 is reduced to 70dB(A) for being an educational institution. During school examination period, the Limit Level is further reduced to 65dB(A). (ii) As described in Section 4.3.3 of the Manual, impact noise monitoring at NM2 would only commence after occupation of the Tung Chung Development. According to the Tung Chung New Town Extension EIA Report (approved on 08 April 2016), the west reclamation area is no longer required and the occupation of Tung Chung West Development will not take place. Thus, impact noise monitoring at NM2 is not required and will not be carried out. (iii) According to Section 4.3.3 of the Manual, the noise monitoring at NM3A was temporarily suspended starting from 1 September 2018 and would be resumed upon the completion of the Tung Chung East Development.

2.2.2 Monitoring Results

The graphical plots of impact noise quality monitoring results during the reporting period are presented in Appendix D. Percentage of monitoring results within their corresponding Action and Limit Levels in the reporting period are presented in Table 2.5.

Table 2.5: Percentage of Noise Monitoring Results within Action and Limit Levels

	NM1A	NM4	NM5	NM6
Jan 2025	100%	100%	100%	100%
Feb 2025	100%	100%	100%	100%
Mar 2025	100%	100%	100%	100%
Apr 2025	100%	100%	100%	100%
May 2025	100%	100%	100%	100%
Jun 2025	100%	100%	100%	100%
Jul 2025	100%	100%	100%	100%
Aug 2025	100%	100%	100%	100%
Sep 2025	100%	100%	100%	100%
Oct 2025	100%	100%	100%	100%
Nov 2025	100%	100%	100%	100%
Dec 2025	100%	100%	100%	100%
Overall	100%	100%	100%	100%
Note: The percentages are calculated by dividing the number of monitoring results within their corresponding Action and Limit Level by the total number of monitoring results.

No complaints were received from any sensitive receiver that triggered the Action Level.

General weather conditions throughout the impact monitoring period were recorded and are summarized in Table 2.6.

Table 2.6: General Weather Condition during Impact Noise Monitoring

	Weather
Jan – Mar 2025	Sunny to Cloudy
Apr – Jun 2025	Sunny to Cloudy
Jul – Sep 2025	Sunny to Cloudy
Oct – Dec 2025	Sunny to Cloudy

2.2.3 Conclusion

The dominant noise sources observed at the monitoring stations during the construction noise impact monitoring were road traffic noise near NM1A, school activities at NM4, and aircraft noise near NM6. As the sensitive receivers were far away from the construction activities, and with the implementation of noise control measures, there was no adverse impact attributable to the works of the Project at the sensitive receivers.

2.3 Water Quality Monitoring

The construction phase water quality impact monitoring was carried out according to Section 5.1.8 of the Updated EM&A Manual. With the completion of land formation works including seawall construction and all marine filling works in the first quarter of 2023, termination of the construction phase water quality impact monitoring was proposed to EPD with approval granted on 30 October 2023. The water quality impact monitoring was terminated after 31 October 2023.

A post-construction phase water quality monitoring exercise was carried out for four weeks according to Section 5.1.10.1 of the Updated EM&A Manual, in the same manner as the impact monitoring at all impact monitoring stations, sensitive receiver stations and control stations during construction phase, from 14 November 2023 to 9 December 2023. The comparison between the baseline, construction phase and post-construction phase monitoring results was presented in the Annual EM&A report No.8. The post-construction phase water quality monitoring did not reveal any significant changes in water quality compared to the baseline monitoring. It can therefore be concluded that the marine works carried out during construction phase did not cause deterioration or adverse impacts on the marine water quality surrounding the Project site.

2.4 Waste Monitoring

In accordance with the Manual, the waste generated from construction activities was audited once per week to determine if waste was being managed in accordance with the Waste Management Plan (WMP) prepared for the Project, contract specific WMP, and any statutory and contractual requirements. All aspects of waste management including waste generation, storage, transportation, and disposal were reviewed during the audits.

2.4.1 Action and Limit Levels

The Action and Limit Levels of the construction waste are provided in Table 2.7.

Table 2.7: Action and Limit Levels of the Construction Waste

Monitoring Stations	Action Level	Limit Level
Construction Area	When one valid documented complaint is received	Non-compliance of the WMP, contract-specific WMPs, any statutory and contractual requirements

2.4.2 Summary of Monitoring Results

Weekly monitoring on all works contracts were carried out by the ET in the reporting period to check and monitor the implementation of proper waste management practices.

Recommendations made included provision and maintenance of proper chemical waste storage area, as well as proper handling, segregation, and regular disposal of general refuse. Paper, plastics, and metals were recycled in the reporting period. The contractors implemented the recommended measures to improve waste management issues. Waste management audits were carried out by ET according to the requirement of the WMP, the Manual, and the implementation schedule of the waste management mitigation measures in Appendix C.

The construction waste generated in the reporting period is summarized in Table 2.8.

Table 2.8: Statistics of Construction Waste Generated in the Reporting Period

	Construction and Demolition Material Stockpiled for Reuse or Recycle⁽¹⁾ (m³)	Construction and Demolition Material Reused in the Project (m³)	Construction and Demolition Material Reused in other Projects (m³)	Construction and Demolition Material Transferred to Public Fill (m³)	Chemical Waste (kg)	Chemical Waste (L)	General Refuse (tonne)
Jan 2025	1,583	160	0	8,037	0	0	4,472
Feb 2025	8	11,494	0	7,826	350	0	2,959
Mar 2025	0	1,334	0	6,218	300	0	4,520
Apr 2025	760	1,885	0	4,680	0	0	4,336
May2025	692	841	0	3,654	0	600	3,282
Jun 2025	782	577	0	2,964	0	0	3,209
Jul 2025	936	756	0	4,788⁽²⁾	0	0	3,533
Aug 2025	671	4,585	0	6,283⁽²⁾	0	2,000	3,217
Sep 2025	856	7,412	0	4,461⁽²⁾	0	0	3,675
Oct 2025	798	1,326	0	4,591	0	0	3,395
Nov 2025	1,492	65	0	3,834⁽²⁾	0	0	2,739
Dec 2025	839	0	0	4,642⁽²⁾	0	0	2,511
Total	9,417	30,435	0	61,978	650	2,600	41,848
Notes: 1. The excavated materials were temporarily stored at stockpiling area and would be reused in the Project. 2. Updated figures were provided by contractors

There were no complaints, non-compliances of the WMP, contract-specific WMPs, statutory and contractual requirements that triggered Action and Limit Levels in this reporting period.

2.4.3 Marine Sediment Management

Marine sediment was managed according to the EIA Report, Updated EM&A Manual and WMP and the proposal of Further Development on Treatment Level / Details and the Reuse Mode for Marine Sediment (hereinafter referred to as “Further Development Proposal”) of the Project. Based on EIA requirements, marine sediments would be treated using cement mixing and stabilisation/solidification method. All these treated sediments would be reused on-site as backfilling materials. The sampling process, storage conditions of the excavated marine sediment, treatment process, final backfilling location as well as associated records were inspected and checked by ET and verified by IEC to ensure they were in compliance with the requirements as stipulated in the WMP and Further Development Proposal.

The excavation and treatment of all marine sediment excavated from areas with ground improvement works by DCM (refer to Section 2.4.3.1) were completed in February 2025. For areas without ground improvement works by DCM (refer to Section 2.4.3.2), the treatment and backfilling of all marine sediment were completed in 2022.

2.4.3.1 Reclaimed Land Area with Ground Improvement Works by Deep Cement Mixing

With reference to the Further Development Proposal approved on 17 January 2020, the marine sediment generated from the areas with ground improvement works of the 3RS Project was treated in-situ with cement by DCM, and the excavated materials would be reused on-site without disposal to sea, it was considered more appropriate to have the excavated materials tested against Risk Based Remediation Goals (RBRGs). Therefore, as an alternative to the testing arrangement presented in the 3RS EIA Report, the assessment approach provided in the EPD’s Practice Guide for Investigation and Remediation of Contaminated Land (hereafter referred to as “Practice Guide”) was adopted and the quality of excavated marine sediment was assessed against the most stringent RBRG limits (for Rural Residential Land Use) for eight heavy metals including Arsenic, Cadmium, Chromium, Lead, Mercury, Nickel, Zinc and Copper.

If the testing results were below the RBRGs limits, no further environmental treatment would be required for the marine sediment materials excavated from the sampling grid. However, geotechnical treatment might require for marine sediment to improve the quality as backfilling materials. If there was RBRGs exceedance in a particular heavy metal at a certain sampling depth, only excavated sediment material from such sampling depth of the concerned sampling grid, would undergo further cement stabilization, before testing against the Toxicity Characteristics Leaching Procedure (TCLP) limit of the concerned heavy metal (heavy metal parameter exceeded RBRGs) before reuse. For TCLP limits, please refer to Table 2.9 (Table 4.6 of the Practice Guide). The excavated sediment materials from such sampling depth with exceedance of RBRGs, would be tested against Unconfined Compressive Strength (UCS) after treatment. The UCS was defined based on respective engineering requirements. The testing frequency for TCLP was the same as that described in Section 10.5.1.14 of the approved EIA Report, i.e. one sample per 50 m³ for the first 1,000 m³ batch of excavated sediment materials. Provided that the samples meet the TCLP limit(s), the subsequent testing frequency would be reduced to be at least two samples per 10,000 m³ batch. In the event that the required level was not achieved, the concerned whole batch should be crushed and the material would be further handled and treated as necessary. The testing frequency should be revised to one sample per 50 m³ batch (with two further samples kept for contingency) and treated samples should be taken for laboratory testing. Once the concerned heavy metal complied with the particular TCLP limit, the previous sampling frequency of at least two samples per 10,000 m³batch should be resumed.

Table 2.9: Universal Treatment Standards for On-site Reuse of Sediment Treated by Cement Mixing and Stabilization

Parameters⁽¹⁾⁽²⁾	TCLP Limit (mg/L)
Arsenic	5
Cadmium	0.11
Total Chromium	0.6
Lead	0.75
Mercury	0.025
Nickel	11
Zinc	4.3

Notes:

1. Universal Treatment Standard – US 40 CFR 268.48

2. For copper, it must be reduced by at least 90% in mobility for copper through cement stabilization/solidification remedial treatment. The reduction of mobility of copper (leachable metals contaminant) should be confirmed through TCLP tests (i.e. to carry out TCLP test for the untreated sediment and for the sediment after treatment and to compare the concentrations of copper in the leachates).

A sampling grid size of 100 m x 100 m was adopted for locating sampling points for areas where marine sediment to be excavated from the newly reclaimed area. One marine sediment sample was taken if the depth of marine sediment to be excavated was less than or equalled to 3 m. If the depth of marine sediment to be excavated was less than or equalled to 6 m, a sample was taken from the depth of 0 - 3 m, and 3 - 6 m. If the marine sediment to be excavated was more than 6 m, a sample was taken from three different depths including one in the depth of 0 - 3 m, 3 - 6 m, and 6 m to the bottom of the marine sediment to be excavated. All of the above tests were carried out by HOKLAS laboratory, and the results were checked by ET and IEC.

The tentative location of sampling grids where marine sediment is to be excavated from the newly reclaimed area land was presented in Appendix A of the Further Development Proposal. Figure 2.2 illustrates all the sampling grids covering the areas where marine sediment was excavated from the newly reclaimed land. The sampling grid for each area is denoted by specific colour, the sampling grids with light green and light red shaded represent all sampling layer(s) passed RBRGs limit(s) and sampling layer(s) with parameter(s) exceeding RBRGs limit(s), respectively. Details of sampling ID and sampling depths are also presented in each sampling grid. The number of grids for sampling for each area, the number of grids with pass and fail of the RBRGs results and the number of grids with marine sediment not encountered within the final excavation level are all summarised in Table 2.10. All the marine sediment sampling works within the reclaimed land area were completed in 2023. However, as there is no schedule that excavation will be required for the western portion of the Terminal 2 Concourse (T2C) until completion of the works, marine sediment sampling is not required for this area at present and will be subject to future development.

Table 2.10: Summary of Marine Sediment Testing Results for Sampling Grids within the Reclaimed Land Area with Excavation

Sampling Area	Western Vehicular Tunnel and Airport North Fire Station	Eastern Vehicular Tunnel	Terminal 2 Concourse (T2C)	APM/BHS Tunnel and Ancillary Building with Piled Foundation
Total No. of Grids for Areas where Marine Sediment was Excavated (a)+(b)+(c)	16	11	36	34
No. of Grids with “Pass” RBRGs Results (a)	15	7	34	30
No. of Grids with “Fail” RBRGs Results (b)	0	0	2	3
No. of Grids with Marine Sediment Not Encountered within the Final Excavation Level (c)	1	4⁽¹⁾	0	1
Total No. of Grids for Areas where Excavation or Marine Sediment Sampling is not Required under Current Status	0	0	14⁽²⁾	0
Notes: 1. RBRG testing was conducted for one of the sampling grids and the testing results exceeded the RBRG limits. However, the contractor re-confirmed that the marine sediment excavation will not reach the “fail” RBRG level. 2. There is no schedule that excavation will be required at the western portion of the T2C until completion of the works. Therefore, no marine sediment sampling or excavation is required for this area under current status.

2.4.3.1.1 Western Vehicular Tunnel and Airport North Fire Station

The Western Vehicular Tunnel (WVT) and Airport North Fire Station were covered by Contracts 3303 and 3310. Out of the total of 16 sampling grids for WVT and Airport North Fire Station, 1 sampling grid was recorded with no marine sediment encountered within the final excavation level and the testing results of the remaining 15 sampling grids passed all the RBRGs limits.

Western Vehicular Tunnel

The construction of WVT was covered by Contracts 3303 and 3310. For Contract 3310, there was 1 sampling grid, and the testing result indicated no marine sediment was encountered within the final excavation level. Therefore, no marine sediment was generated from the works carried out by Contract 3310. For Contract 3303, there were 14 sampling grids, and all the testing results passed the RBRGs limits. A total of 508,506 m³of treated marine sediment was backfilled, and the backfilling locations are shown in Figure 2.3. The marine sediment excavation, treatment and backfilling works were completed in this area in 2024.

Airport North Fire Station

The construction of Airport North Fire Station was covered by Contract 3303. There was 1 sampling grid for this area, and the testing results passed all the RBRGs limits. A total of 9,269 m³of treated marine sediment was backfilled. The backfilling location is shown in Figure 2.3. The marine sediment excavation, treatment and backfilling works were completed in this area in 2024.

2.4.3.1.2 Eastern Vehicular Tunnel and Terminal 2 Concourse

The construction activities of Eastern Vehicular Tunnel (EVT) and Terminal 2 Concourse (T2C) were covered by Contracts 3310 and 3408 and 3405. Out of the total of 47 sampling grids for EVT and T2C, 4 sampling grids were recorded with no marine sediment encountered within the final excavation levels, 2 sampling grids with Arsenic exceeding the corresponding RBRGs limit were recorded and the testing results of the remaining 41 sampling grids passed all the RBRGs limits.

Eastern Vehicular Tunnel

The construction of EVT was covered by Contracts 3310 and 3408. For Contract 3310, there was 1 sampling grid, and the testing result indicated no marine sediment was encountered within final excavation level. Therefore, no marine sediment was generated from Contract 3310. For Contract 3408, out of a total of 10 sampling grids, 3 sampling grids were recorded with no marine sediment encountered within the final excavation level and the testing results of the remaining of 7 sampling grids passed all the RBRG limits. A total of 11,305 m³ of treated marine sediment was backfilled, and the backfilling locations are shown in Figure 2.3. The marine sediment excavation, treatment and backfilling works were completed in this area in 2025.

Terminal 2 Concourse

The construction of T2C was covered by Contract 3405. Out of the total of 36 sampling grids, 2 sampling grids were recorded with Arsenic exceeding the corresponding RBRGs limit and the testing results of the remaining 34 sampling grids passed all the RBRG limits. A total of 152,168 m³ of treated marine sediment, which includes the marine sediment that passed all the RBRGs limits and the marine sediment that exceeded RBRGs limit for Arsenic but had undergone environmental treatment, was backfilled and the backfilling locations are shown in Figure 2.3. The marine sediment excavation, treatment and backfilling works were completed in this area in 2024.

There is no schedule that excavation will be required at the western portion of the T2C until completion of the works. Therefore, marine sediment sampling is not required for this area under the current status. This would, however, be subject to any future development programme at this area.

2.4.3.1.3 APM / BHS Tunnel and Ancillary Buildings with Piled Foundations

The construction activities of APM / BHS Tunnel and Ancillary Buildings with Piled Foundations were covered by Contracts 3802, 3804 and 3805. Out of the total of 34 sampling grids for such areas, 1 sampling grid was recorded with no marine sediment encountered within the final excavation level, 3 sampling grids were recorded with Arsenic exceeding the corresponding RBRGs limit and the testing results of the remaining 30 sampling grids passed all the RBRGs limits.

APM / BHS Tunnel

The construction of APM/ BHS Tunnel was covered by Contract 3802. Out of 33 sampling grids completed under this contact. 1 sampling grid was recorded with no marine sediment encountered within the final excavation level, 3 sampling grids were recorded with Arsenic exceeding the corresponding RBRGs limit and the testing results of the remaining 29 sampling grids passed all the RBRGs limits. Up to this reporting period, a total of 952,108 m³ of treated marine sediment, including the marine sediment that passed all the RBRGs limits and the marine sediment that exceeded RBRGs limit for Arsenic but had undergone environmental treatment, were backfilled and the backfilling locations are shown in Figure 2.3. Additionally, 46,311 m³ of treated marine sediment is properly stockpiled at 3RS Project site area, awaiting backfilling and the backfilling location will be reported in the next annual report. Accordingly, the marine sediment excavation and treatment works were completed in this area in February 2025.

Ancillary Buildings with Piled Foundations

The construction activities of East Fire Station and Landside Fire Station were covered by Contract 3804. There was 1 sampling grid that was done by Contract 3804 and the testing result of the grid passed all the RBRGs limits. However, the excavation areas for East Fire station and Landside Fire Station spread over a total of 6 sampling grids, which include 5 sampling grids done by Contract 3802, namely, 3802-BHS/APM-Grids 6, 18, 19, 20 & 21, and 1 sampling grid done by Contract 3804, namely, 3804-EFS-Grid 34 (refer to Figure 2.2). Out of these 6 sampling grids, 1 sampling grid was recorded with Arsenic exceeding the corresponding RBRGs limit and the testing results of the remaining 5 sampling grids passed all the RBRGs limits. A total of 7,254 m³oftreated marine sediment, which includes the marine sediment that passed all the RBRGs limits and the marine sediment that exceeded RBRGs limit for Arsenic but had undergone environmental treatment, were backfilled, and the backfilling locations are shown in Figure 2.3. The marine sediment excavation, treatment and backfilling works were completed in this area in 2025.

The construction of New Airport District Police Operational Base was covered by Contract 3805. The excavation area for New Airport District Police Operational Base spreads over a total of 4 sampling grids that were done by Contract 3802, namely, 3802-BHS/APM-Grids 11, 13, 32 & 33 (refer to Figure 2.2), and the testing results of all these 4 sampling grids passed the RBRGs limits. Up to this reporting period, a total of 16,049 m³ of treated marine sediment was backfilled, and the backfilling location is shown in Figure 2.3. The marine sediment excavation and treatment works were completed in this area in 2024. However, another 1,159 m³ of treated marine sediment is stockpiled properly at 3RS Project site area awaiting backfilling and the backfilling location will be reported in the next annual report.

2.4.3.1.4 Summary of Backfilling of Marine Sediment within the Reclaimed Land Area

The backfilling locations of treated marine sediment, denoted by specific colours according to the excavation areas, are shown in Figure 2.3. A summary of the backfilling volumes, along with the status of marine sediment from different excavation areas, is presented in Table 2.11.

Table 2.11: Summary of Backfilling Status of Marine Sediment within the Reclaimed Land Area

Area	Western Vehicular Tunnel and Airport North Fire Station	Eastern Vehicular Tunnel	Terminal 2 Concourse	APM/BHS Tunnel	Ancillary Building with Piled Foundation
Contract No.	3303 and 3310^(a)	3408 and 3310^(a)	3405	3802	3804 and 3805
Status	Excavation, treatment and backfilling works completed in 2024.	Excavation, treatment and backfilling works completed in 2025.	Excavation, treatment and backfilling works completed in 2024.	Excavation and treatment works completed in February 2025. Backfilling to be completed.	Excavation and treatment works completed in 2025. Backfilling to be completed.
Volume of Treated and Backfilled Marine Sediment, m³	508,506 + 9,269 = 517,775	11,305	152,168	952,108	7,254 + 16,049= 23,303
Volume of Treated Marine Sediment awaiting backfilling, m³	0	0	0	46,311	1,159

Notes:

(a) No marine sediment was generated from Contract 3310.

2.4.3.2 Area without Ground Improvement Works by Deep Cement Mixing

For the excavated marine sediment generated from the areas without ground improvement works by DCM (i.e. construction berth at Area C5 of the reclaimed land area, existing airport island area and approach light area), the excavated marine sediment was treated with cement and tested against the TCLP limits as provided in Table 2.9. The testing frequency follows Section 10.5.1.14 of the approved EIA Report, as detailed in Section 2.4.3.1. The treated marine sediment was tested against relevant engineering requirements to confirm their suitability as backfilling material for respective areas of different future uses. The UCS was also tested and defined based on respective engineering requirements.

As presented in the Annual EM&A Report No. 8, the marine sediment excavation, treatment and backfilling works for the areas without ground improvement works by DCM were completed in 2022 and there was no update during this reporting period. The following sections provide a summary on the volumes of excavated, treated and backfilled marine sediments for different areas as reproduced from the Annual EM&A Report No. 9.

2.4.3.2.1 Construction Berth at Area C5 of the Reclaimed Land Area

A construction berth was constructed at the eastern portion of newly reclamation area by Contract 3206. The marine sediment excavation, treatment and backfilling works were completed in this area in 2022. A total of 117 m³of excavated and treated marine sediment was backfilled and the backfilling location is shown in Figure 2.3.

2.4.3.2.2 T2 Foundation and Substructure Works

Marine sediment was excavated and treated with cement stabilisation by Contract 3503. A total of 72 m³ of excavated and treated marine sediment was backfilled and the backfilling locations are shown in Figure 2.3. The marine sediment excavation, treatment and backfilling works were completed in this area in 2022.

2.4.3.2.3 Approach Light Area

The marine sediment generated from Approach Light Area was covered by Contract 3303. A total of 2,404 m³ of excavated and treated marine sediment was backfilled and the backfilling location is shown in Figure 2.3. The marine sediment excavation, treatment and backfilling works were completed in this area in 2022.

2.5 Chinese White Dolphins

According to Sections 10.2.1.2 and 10.2.1.3 of the Updated EM&A Manual, CWD monitoring is required during the baseline, construction, post-construction and operation phases of the project. The construction and post-construction phase monitoring of CWDs ended in December 2023 and December 2024 respectively while the 12 months operation phase monitoring commenced on 1 January 2025 and was completed in December 2025.

The aims of CWD monitoring during the operation period are:

● to monitor the potential shift in the CWD travelling areas and habitat use;

● to provide a dataset compatible with the AFCD long-term monitoring, stratified in such a way as to allow the calculation of density and abundance for the different phases and to calculate the trends from these estimates;

● to detect any rebound in use of areas north and east of HKIA during the implementation of the North Lantau Marine Park as mitigation for habitat loss for the airport expansion; and

● to evaluate the overall, long-term impacts of the project on CWDs.

This section summarises the results of the CWD operation phase monitoring effort over a 12-month period from January 2025 through December 2025, to gather information on the spatial and temporal distribution patterns as well as calculate density and abundance of CWD in western Hong Kong waters. Supplementary information collected focusing on northwestern Lantau waters, including habitat use and behaviours of CWD during the post-construction phase of the Project, has also been reviewed.

This reporting period is effectively a full year of operation phase monitoring of CWDs. This annual report reviews the operation phase monitoring data for 2025 and compares it with the post-construction phase monitoring data for the previous years.

CWD monitoring was conducted by undertaking vessel line-transect surveys. The vessel line transects covered Northeast Lantau (NEL), Northwest Lantau (NWL), Airport West (AW), West Lantau (WL) and Southwest Lantau (SWL) at a frequency of two full surveys per month as proposed in Section 10.2.3.2 of the Updated EM&A Manual, which is consistent with the AFCD long-term monitoring programme (except AW). The locations of the CWD vessel survey transects are shown in Figure 2.4.

Additional survey effort was collected on a voluntary basis at the same frequency of two surveys per month from Deep Bay (DB) (refer to Appendix E for the location of this additional survey), which is an area that historically had CWDs in the outer bay, to establish a more comprehensive understanding of CWD distribution and abundance. All the DB data were considered supplemental and were only used for density and abundance estimation.

Density and abundance analysis made use of both conventional distance sampling (CDS) and a more sophisticated approach – multiple covariate distance sampling (MCDS) to estimate CWD abundance for the waters of Hong Kong. The additional analysis using MCDS is more time-consuming and labour-intensive than CDS as it uses information on environmental factors that are likely to affect detection probability (such as variables describing sighting conditions), but generally produces estimates with higher precision (i.e., lower variances and CVs) (Marques and Buckland, 2003 & 2004). However, datasets with small sample sizes (not unusual in marine mammal studies) can make it difficult or impossible to achieve model “convergence” in some MCDS analysis, and thus it is critical to always start each analysis with CDS methods (this also helps to determine the appropriate truncation distance and overall modelling approach).

Based on the vessel survey data, seasonal differences in dolphin density and use of the study area were examined, using the solar seasons (Winter: December-February, Spring: March-May, Summer: June-August, Autumn: September-November) and/or oceanographic seasons (Dry: October-March, Wet: April-September).

The travelling patterns in different areas were reviewed by using photo-identification of individual dolphins and their re-sighting locations, depicting the range use and cross-area movement of re-sighted individuals, where practicable.

2.5.1 Summary of Monitoring Results

2.5.1.1 Summary of Vessel Line-transect Survey Monitoring Results

2.5.1.1.1 Survey Effort

During the reporting period from January 2025 to December 2025, surveys were completed in NEL, NWL, AW, WL, and SWL survey areas. A total of around 5352.7 km survey effort was collected in this reporting period.

Around 97.2% (5201.5 km) of the survey effort was collected under favourable weather conditions (i.e. Beaufort 0-3 and visibility of approximately 1200 m or beyond), and can be utilised in analysis of encounter rates, density and abundance.

The breakdown of the survey effort by survey areas is tabulated in Table 1 of Appendix E. A detailed record of the survey effort data is also provided in Appendix E.

2.5.1.1.2 Sighting Distribution

During the reporting period, a total of 166 groups consisting of 466 CWDs were sighted in NWL, AW, WL and SWL survey areas. Among all these sightings, 165 groups with 464 CWDs were sighted during on-effort surveys under favourable weather conditions (Beaufort 0-3 and visibility of approximately 1200 m or beyond). The off-effort sightings were excluded from analysis in the following sections. Breakdown of the sightings by survey areas are tabulated in Table 2 of Appendix E, and the sighting locations of CWDs during this reporting period are depicted in Figure 1 of Appendix E.

In NWL (including AW transects), 11 CWD sightings were recorded, accounting for 7% of the total sightings. These sightings were mainly clustered at the western waters of the airport, along with a few sightings scattered around Sha Chau to the North of Lung Kwu Chau. Overall, there were more sightings recorded in NWL in 2025 than in 2024 (i.e. six sightings including AW transects).

In WL, 124 CWD sightings were recorded, accounting for 75% of the total sightings. CWD sightings were recorded on all transects and were distributed quite evenly over the entire survey area, particularly between Tai O and Fan Lau.

In SWL, 30 CWD sightings were recorded, accounting for 18% of the total sightings. Sightings of CWDs were scattered over the entire survey area in relatively coastal waters with more sightings located in the western end near Fan Lau.

No CWDs were recorded in NEL survey area.

2.5.1.1.3 Density and Abundance Estimation

Line-transect analysis to estimate the density and abundance of CWDs in Hong Kong waters during the reporting period was conducted using the same basic methods as in previous analysis (note that the changes in the size of the different survey areas over the past few decades have been taken into account in the line-transect analysis for this year, with the total area of the NWL area being reduced to account for this loss of potential habitat). Although it was experimented with Beaufort sea state as a co-variate, for 2025 the best estimate of abundance was obtained using Conventional Distance Sampling and a half-normal model with a cosine adjustment (effective strip width = 185 m). The detection function of 3RS CWD monitoring data of this reporting period is shown in Figure 2 of Appendix E and the various parameters of the 2025 estimates are shown in Table 3 of Appendix E. The overall abundance estimated for this reporting period (incorporating an entire year of data from all four seasons) was 30 CWDs (CV = 19.4%, just below what is considered a good level of precision of <20%). This is lower than estimates from the last three years (i.e., 2022 to 2024). For comparison, 2024 estimate was 60 CWDs (CV = 21.9%), the 2023 estimate was 40 CWDs (CV= 14.4%), the 2022 estimate was 35 CWDs (CV = 15.8%). As in all recent years, the area with the highest abundance and density in 2025 was WL (N=24, D=72/100 km²; this has been consistent over the AFCD long-term records that WL has been the area with the highest CWD abundance and density). NWL showed similarly low numbers of dolphins from the previous year (1 in 2025 and 1 in 2024). SWL showed a decrease (from 15 to 5). The CWD densities in NWL and SWL were 2 and 7.5 individual(s) per 100km² respectively. NEL registered an abundance of zero, which has been the case in most of the last 10-12 years, observed from both AFCD’s and 3RS’s monitoring. The overall decrease in abundance estimated in 2025 should not be taken as an indication of a long-term trend. We appeared to be seeing the beginnings of a recovery since 2021 (after dolphins moved away from the 3RS works area in past years), and clearly we are not yet seeing signs of a strong recovery in numbers north of Lantau Island. The drop of CWD abundance in NWL since about 2010 is thought to be partly related to the impacts from the construction of the Hong-Kong-Zhuhai-Macao Bridge (HZMB) (Jefferson 2018 and Huang et al. 2024). The HZMB impacts on dolphins were expected between 2011-2016 during its construction phase, and in fact, this time period saw a significant drop in numbers of dolphins in Hong Kong (see Jefferson 2018; Jefferson et al. 2023). Huang et al. (2024) reported an increase of CWD abundance in Lower Lingding Bay (where majorly connected to WL and SWL) during 2020-21 (i.e. classified as post-construction phase of HZMB project by their study) which is aligned with the beginning of a potential recovery observed from 3RS monitoring results in 2021. Though this will require further examination, a generally increasing trend of CWD abundance since the completion of 3RS marine works in 2021 (despite the drop in 2025) is consistent with what was predicted in the 3RS EIA: that further drops in CWD numbers during the 3RS construction are expected, followed by a likely rebound towards pre-3RS construction levels in the period after completion of 3RS marine works and establishment of the North Lantau Marine Park (which came into effect in November 2024).

It is worth noting that the 3RS EIA predicted significant impacts on CWDs (Mott MacDonald 2014), and a drop in numbers of dolphins in the area during the most intensive part of the 3RS construction phase was expected. Reclamation filling works were substantially completed in 2021 and some recovery after the main marine filling and reclamation works finished was anticipated. However, the longer term rebound will need to be examined with more data over several years, as recovery may take some time, and fluctuations from year to year can be expected in the context of any overall trend. Cumulative impacts due to the 3RS Project with other concurrent projects (e.g., reclamation works near Tung Chung in recent years which was completed in Jan 2023, for instance) will become clearer as monitoring efforts continue.

In addition to estimating year-round abundance for each of the survey areas, a seasonal analysis was also conducted (the pooled dataset from all survey areas was used, as stratifying by both survey area and season would reduce the sample sizes that result in estimates with unacceptably low levels of precision) (refer to Table 3 of Appendix E). The spring estimate was the lowest (N=32 dolphins), with the summer estimate showing the highest numbers (N=37 dolphins). This is similar to past records of dolphin numbers in Hong Kong, where autumn or summer is usually the high season and spring the low season.

2.5.1.1.4 Quantitative Grid Analysis on Habitat Use

Quantitative grid analysis was conducted to examine the habitat use amongst the survey areas, both SPSE (no. of on-effort sightings per 100 units of survey effort) and DPSE (no. of dolphins per 100 units of survey effort) values for each 1 km² grid were calculated in all grids amongst all survey areas for the period from January 2025 to December 2025. SPSE and DPSE of the current reporting year and the previous reporting years are depicted in Figure 3 of Appendix E.

There was an increase of CWDs’ usage of waters in NWL in 2025 compared to the previous year, with more usage of waters around SCLKCMP and in the area to the west of HKIA. Although this observation does not imply a sustained population recovery, it is still a good sign of dolphin recovery in NWL and monitoring should be continued in coming years.

The important dolphin habitats in WL survey area in 2025 are similar to 2024. Grids with high SPSE and/or DPSE value(s) in WL were near Tai O, Yi O, Peaked Hill and Fan Lau.

In SWL, there was a decrease of CWDs’ usage, reflected by both SPSE and DPSE, at the waters between Soko Islands and Lo Kei Wan and between Soko Islands and Fan Lau in 2025 after a mild rebound in 2024.

Cumulative SPSE and DPSE values were also calculated by using the 3RS CWD monitoring data since mid-December 2015 and are depicted in Figure 4 of Appendix E. Grids in western waters of Hong Kong with higher dolphin density are restricted to waters off West Lantau, at Tai O, Yi O, Peaked Hill and Fan Lau.

2.5.1.1.5 Group Size

During the reporting period from January 2025 to December 2025, group size of CWDs ranged from 1 to 15 dolphins, with an average of 2.81, based on all on-effort CWD sightings. The average group sizes of NWL, AW, WL and SWL were 2.22, 2.00, 2.81 and 3.07 respectively. By four solar seasons, the average group size of CWDs was the highest in autumn (3.38) but the lowest in spring (2.47). The summaries of the average group size of CWDs by survey area and by season are presented in Table 4 and Table 5 of Appendix E.

CWD sightings with small group size (i.e. 1 to 2 dolphins per group) were dominant in 2025 with around 59.4% all on-effort sightings. Three sightings, which accounted for 1.8% of all sightings, were large CWD groups with 10 or more dolphins per group.

Both small and medium CWD groups were generally sighted throughout the distribution range of dolphins in NWL, WL and SWL waters in 2025, except the observation that most sightings in the west of airport are in small-sized groups. Those three large-sized CWD groups were recorded in WL near Tai O, Peaked Hill and Fan Lau respectively. The sighting distribution of CWDs with different group sizes is illustrated in Figure 5 of Appendix E.

2.5.1.1.6 Activities and Association with Fishing Boats

Vessel surveys do not provide the most unbiased information on the behaviour and activities of dolphins, due to the potentially disturbing presence of the vessel itself, and also the low vantage point of small vessels. However, behaviour and activity data are useful in gauging where and how dolphins are spending their time, with short and longer term (inter-year) comparisons of potential changes and therefore continue to be collected from the vessel surveys.

During the reporting period, a total of 42, 14, 10 and 1 groups of CWDs were observed engaging in foraging, travelling, socialising and resting/milling activities, comprising of 25%, 8%, 6% and 1% of all on-effort CWD sightings respectively. The sighting locations of CWD groups engaged in different types of activities are depicted in Figure 6 of Appendix E while the percentages of different activities for each of the survey areas are shown in Table 6 of Appendix E.

In NWL, all foraging and resting/milling activities occurred at the west of the airport while a sighting with traveling activity was recorded within the SCLKCMP. The occurrence of foraging activities observed west of the airport may suggest that AAHK’s recent habitat enhancement measures such as the deployment of artificial reefs (ARs) and shellfish reef (SRs) and also the implementation of eco-enhanced seawalls and several rounds of fish restocking have contributed to improvements in local marine environmental conditions, thereby potentially increasing habitat suitability for CWDs in this area. Monitoring will continue and will help to indicate if there is any sustained recovery of CWDs in the area. In NWL, 33% of CWD sightings were engaged in feeding activity, which was slightly lower compared to the previous year (40% in 2024).

In WL, foraging, socialising and traveling activities of CWDs occurred throughout the entire survey area. No CWD sightings engaged in milling/resting activities was recorded in WL survey area. In WL, 23% of CWD sightings were engaged in feeding activity, which is slightly higher than the 21% recorded in 2024.

In SWL, the sightings with observed activities were clustered at the western water of the survey area, with a few sightings in the northern water of Soko Island. Travelling activities occurred near Fan Lau and the northern waters of Soko Island. Socializing activities in SWL only occurred at Fan Lau. About 33% of the CWD sightings in the survey area were engaged in feeding activity, which is slightly higher than that recorded in 2024 (i.e. 29%).

A total of 18 sightings of CWDs were observed associating with operating fishing boats, including gill netters (three groups), shrimp trawler (three groups) and purse seiners (12 groups), accounting for 10.9% of all on-effort sightings in 2025. CWDs’ association with operating fishing boats in 2025 showed an increase compared to that of last year (6.6% in 2024). Although trawling is prohibited in Hong Kong waters, however, in most cases, the trawlers observed were operating along the waters of the HKSAR boundary.

Observations of CWD association with operating fishing boats were scattered in WL and SWL. In WL, association with gill netters, shrimp trawler and purse seiners scattered throughout the northern waters of Peaked Hill, with one observation of association with purse seiners recorded near Fan Lau. While in SWL, only associations with operating purse seiners were observed and all these records are located in waters around and Fan Lau and Kau Ling Chung. The sighting locations of CWD groups associated with operating fishing boats are depicted in Figure 7 of Appendix E.

2.5.1.1.7 Mother-calf / Mother-unspotted Juvenile Pairs

During the reporting period, a total of 28 sightings were observed with the presence of mother-and-unspotted calf (UC) and/or mother-and-unspotted juvenile (UJ), which accounted for about 17.0% of all on-effort sightings of 2025. The number of sightings with the presence of mother-calf pair(s), was higher than that of 2024 (25 sightings). This indicates that Hong Kong western waters continue to function as an important nursery area for CWDs and suggests that the habitat remains suitable for supporting the reproduction and early life-stage development of CWDs, which is a key prerequisite for any potential long-term recovery of CWD population in Hong Kong waters. The percentages of sightings with the presence of mother-calf pair(s) in WL and SWL were 16.9% and 23.3% respectively. These percentages were calculated by dividing the number of sightings with mother-calf pair(s) of a survey area by the total number of on-effort sightings of that survey area.

Amongst the abovementioned 28 sightings, five sightings were observed with the presence of mother-and-UC pair(s), 19 sightings were observed with the presence of mother-and-UJ pair(s) and four sightings were observed with the presence of both mother-and-UC and mother-and-UJ pairs. According to the results of photo-identification, a total of seven mother-calf pairs were successfully identified from these 28 sightings.

Most of the sightings with the presence of mother-calf pair(s) were recorded at the waters near Tai O, Peaked Hill, Fan Lau and Kau Ling Chung. The sighting distribution of mother-calf pairs is depicted in Figure 8 of Appendix E.

2.5.1.1.8 Photo Identification – Summary

In 2025, a total of 12 newly identified CWD individuals were added to the photo-identification catalogues, including two animals added to NL catalogue and 10 animals added to WL catalogue.

Ninety-eight individual CWDs were identified in 2025, with a total of 242 identification records, including multiple re‑sightings of the same individuals. Amongst these 98 CWD individuals, 13, 65 and 20 belonged to NL, WL and SL catalogues respectively. There were 52 individuals (53.1%) that were sighted more than once. Twelve of these 52 re-sighted individuals were sighted five times or more.

The most frequently re-sighted individuals in 2025 were SLMM003 which was sighted 12 times, followed by WLMM114 which was sighted 10 times. SLMM003 was also one of the most frequently re-sighted individuals of the previous reporting year (i.e. being sighted for 11 times in both 2024 and 2023). It is also the most frequently re-sighted individual since the establishment of the photo-identification catalogue, which has been sighted 87 times, followed by SLMM014 (being sighted 83 times), and WLMM001 (being sighted 68 times). There are a few more individuals including NLMM013, NLMM023, WLMM003, WLMM007, WLMM027, WLMM028, WLMM029, WLMM043, WLMM056, WLMM063, WLMM065, WLMM067, WLMM071, WLMM073, WLMM079, WLMM114, WLMM131, SLMM002, SLMM007, SLMM010, SLMM012, SLMM022, SLMM023, SLMM025, SLMM027, SLMM031, SLMM037, SLMM044, SLMM049 and SLMM052, that have been sighted 30 times or more.

Forty-four individuals that appeared in Hong Kong waters in previous years (with 10 or more re-sighting records since the commencement of the monitoring in mid-December 2015) did not appear in our sighting records in 2025 (note that these dolphins may still be using Hong Kong waters but may have not been detected from our surveys). These individuals are NLMM001, NLMM002, NLMM004, NLMM006, NLMM009, NLMM010, NLMM015, NLMM016, NLMM018, NLMM019, NLMM020, NLMM021, NLMM039, NLMM041, NLMM043, NLMM052, SLMM011, SLMM012, SLMM015, SLMM017, SLMM028, SLMM029, SLMM037, SLMM044, SLMM045, SLMM053, SLMM058, SLMM059, WLMM006, WLMM008, WLMM013, WLMM019, WLMM030, WLMM054, WLMM060, WLMM062, WLMM076, WLMM078, WLMM081, WLMM086, WLMM090, WLMM107, WLMM131 and WLMM149. Some of these 44 individuals (i.e. NLMM002, NLMM004, NLMM006, NLMM010, NLMM018, NLMM019, NLMM043, SLMM011, SLMM012, SLMM015, SLMM017 SLMM028, SLMM045, SLMM053, WLMM006, WLMM013, WLMM054, WLMM060, WLMM076, WLMM078, WLMM081, WLMM090, WLMM107 and WLMM131) have not been seen in Hong Kong waters for three or more years. It could not be confirmed that if these animals were occurring elsewhere in mainland waters, or if some of them have already died.

In October 2025, a request from AFCD for seeking assistance in helping to monitor an individual dolphin which entangled in a rope, was received. This individual dolphin was found entangled in a rope in April 2024 by AFCD’s monitoring team. Upon receival of the request from AFCD, the photo-identification catalogue developed under the dolphin monitoring of 3RS project was carefully examined to extract information of this particular dolphin individual. This individual dolphin is WLMM043 which was first identified in July 2016 under the photo-identification catalogue of 3RS project and has been seen 52 times in total during the dolphin monitoring of 3RS project. MMHK’s dolphin monitoring team first observed WLMM043 entangled with a rope on 7 August 2024. Based on the records and observation, WLMM043 looks normal after injury as it still showed foraging behaviour and its range use did not show any significant reduction. However, it was observed that the rope is getting deeper at its neck over time and it tended to appear alone or in smaller group after injury and the most concerning is that WLMM043 was not being encountered since the last record made in May 2025. There are plenty examples of dolphins recovering from injuries caused by entanglement with ropes or nets. Thus, continuous attention should be kept paying on WLMM043 during other on-going dolphin monitoring.

A summary of the photo-identification records of CWDs is presented in Table 7 of Appendix E.

2.5.1.1.9 Photo Identification – Range Use of Identified CWD individuals

SLMM003, the most frequently re-sighted animal in 2025 and also the most frequently re-sighted animal since mid-December 2015, continued to occur frequently in WL and SWL waters. Compared to 2024, SLMM003’s northern end range use in 2025 shrank slightly from Tai O to Yi O, while its range use in WL and its eastern end range use in SWL remained similar.

WLMM114 is the 2^nd most frequently re-sighted animal in 2025. It continued to occur frequently in WL and SWL waters. The extent of its range use remained relatively the same compared to 2024, covering from Tai O to the waters between Fan Lau Tung Wan and Shek Pik.

SLMM014, the 2^nd most frequently re-sighted animal since the establishment of the photo-identification catalogue, continued to frequently utilize WL and SWL waters. Continuing from the last two years, the northern end of SLMM014’s range use in WL further shrank from Peaked Hill to Fan Lau. When compared with earlier years from 2015 to 2023, SLMM014’s range in Hong Kong waters showed a distinct reduction from the west of the HKIA in north Lantau to Shui Hau in south Lantau in earlier years, to the coastal waters between Fan Lau and Shek Pik. Such a reduction in mobility particularly in the past few years may arise from age‑related factors, accumulated stress, or subtle physical or behavioural limitations that are not directly observable during vessel surveys, given that the environmental conditions remain broadly unchanged suitable in these few years based on field observation. Continued attention shall be paid will be on SLMM014’s reduced mobility.

The sighting locations of SLMM003, SLMM014 and WLMM114 are depicted in location maps under Figure 9 of Appendix E, which provide the indicative distribution range use of representative individuals recorded from the 3RS CWD monitoring.

2.5.1.1.10 Photo Identification – Cross-area Movement

Amongst the 52 individuals that were re-sighted more than once in in 2025 31 individuals showed cross-area movement between survey areas. This accounted for about 31.6% of all 98 identified CWD individuals in 2025. Amongst these 31 individuals, 4 (16.7%) were re-sighted in both NWL (including AW) and WL, 27 individuals (87.1%) were recorded in both WL and SWL. There was 1 individual, namely WLMM065, recorded occurring in all three main survey areas (WL, SWL and NWL) in 2025. The sighting locations of WLMM065 are depicted in a location map under Figure 9 of Appendix E.

2.5.1.1.11 Photo Identification – Residency Pattern

The residency patterns of the dolphin individuals identified under this monitoring programme have been examined. For residency pattern analysis, both seasonal and annual occurrence patterns of identified CWD individuals with 15 or more re-sighting records (since the establishment of the photo-identification database) were carefully examined. “Residents” are defined as individual dolphins that were regularly sighted for at least three consecutive years, while “Visitors” are individuals that were intermittently sighted during the past years since the establishment of the photo-identification database. Seasonal occurrence patterns were also examined to distinguish individuals that occurred year-round (i.e. individual dolphins sighted in all four seasons of a year in at least one of the last two years) or seasonally (i.e. individual dolphins that occurred only in certain season(s) of a year). Therefore, there are four combined classifications of the residency pattern of an individual dolphin theoretically. These four classifications are:

“Year-round resident” – dolphin which appears in Hong Kong waters in all four seasons of a year in at least one of the two last years and it was sighted for at least three consecutive years

“Seasonal resident” – dolphin which appears in Hong Kong waters only in certain season(s) of a year and it was sighted for at least three consecutive years

“Year-round visitor” – dolphin which appears in Hong Kong waters in four seasons of a year in at least one of the two last years and it was NOT sighted for at least three consecutive years

“Seasonal visitor” – dolphin which appears in Hong Kong waters only in certain season(s) of a year and it was NOT sighted for at least three consecutive years

Up to year 2025, photo-identification records of 73 dolphin individuals that have at least 15 re-sightings since the establishment of the database were examined. There are 9 individuals namely SLMM002, SLMM003, SLMM007, SLMM014, SLMM023, SLMM073, WLMM067, WLMM079 and WLMM114 being defined as year-round residents. Thirty-three individuals were considered as seasonal residents. Thirty-one individuals are considered as seasonal visitors to Hong Kong waters. Details of the residency pattern of these 73 animals are shown in Appendix E.

2.5.2 Discussion on CWD Monitoring Results

CWD monitoring by vessel surveys has been conducted as required during the construction phase from 2015 to 2023 and post-construction phase in 2024, with substantive marine works largely completed since 2021. The 12 months operation phase monitoring was completed between January and December 2025.

Vessel Line-transect Survey

From the CWD vessel-based monitoring data, the estimate of overall abundance for 2025 was 30 dolphins, which is considerably lower than the 60 dolphins the year before, with a CV of 19.4% (which indicates a good level of precision). This lower estimate is in contrast to the generally increasing trend observed between 2021 and 2024. When reviewing these abundance estimates, It is important to note that the number of sightings/dolphins is only one component of the abundance estimate using line-transect distance sampling method. Other components include: survey effort under different weather conditions, group size of the sightings, distance of the sightings to the transects (i.e. Perpendicular Sighting Distance PSD) and detection probability. These components are influenced by many factors, such as dolphin behaviour (dolphins may change their behaviour or distribution, making them less or more visible during the survey), and environmental and survey conditions (e.g., water, weather, and sea conditions, food availability, or human activities that all influence dolphin visibility and distribution). The lower abundance estimate in 2025 is consistent with a relatively large reduction in average group size (2.2 in 2025 compared to 3.1 in 2024, calculated from distance analysis, refer to Table 3 of Appendix E), which scaled down the estimated abundance in distance analysis, even when the total number of dolphins observed during vessel-survey is similar between the two years.

While the estimate of total dolphin numbers in 2025 was lower than the previous year’s estimate, a change from one year to the next should never be taken as an indication of long-term trends. The seasonal analysis showed that during all four seasons, dolphins are present in the study area in approximately equal numbers. The 2025 seasonal range is 32 in Spring to 37 in Summer, but it was significantly lower than the summer influx of CWDs in 2024 where the summer estimate was 104 dolphins. The pronounced reduction in abundance estimates for CWDs in 2025 particularly during summer coincided with an exceptionally active stormy tropical‑cyclone year in Hong Kong. Compared with 7 tropical cyclones affecting Hong Kong in 2024, a record of 14 tropical cyclones, including 5 super typhoons, affected the territory in 2025. In addition, while no Black Rainstorm Warning and 4 Red Rainstorm Warnings were issued in 2024, 2025 saw a record-breaking 5 Black Rainstorm Warnings and 16 Red Rainstorm Warnings, particularly during June to September. Intense and frequent storm events are known to substantially alter coastal environmental conditions, including increases in turbidity, freshwater input, and water‑column mixing, as well as persistent overcast condition and prolonged periods of elevated sea state before and after typhoon passage. For coastal delphinids such as CWDs, these conditions can alter their distribution and behaviour (such as surfacing and grouping), and visual detectability, even during surveys conducted under nominally acceptable Beaufort sea states (Parson, 2004).

Despite a marked reduction in estimated abundance in 2025, the number of CWDs recorded during vessel surveys was comparable to 2024 (466 dolphins in 2025 vs. 490 dolphins in 2024). The exceptionally stormy conditions in 2025 may have influenced dolphin behaviour and distribution and altered detectability of CWDs. Substantially smaller average group size calculated from distance analysis were observed in 2025 compared to 2024, which potentially lead to a lower abundance estimate. This suggests that the lower abundance estimate in 2025 could reflect an inter-annual fluctuation due to short‑term behavioural responses to predominant extreme weather conditions rather than a true decline in population size.

Although CWD estimates in Hong Kong were relatively stable or increased somewhat from 2016 to 2018 (Jefferson 2018; Jefferson et al. 2023; 3RS Annual EM&A Report 2018), Hong Kong waters have been showing an overall declining trend in dolphin numbers over much of the last two decades or so (see Jefferson 2018; Jefferson et al. 2023), and the 3RS EIA predicted shifting of dolphins away to waters outside Hong Kong and a significant effect on numbers in Hong Kong during intensive periods of construction (EIA Report Section 13.9.2). From 2018-2021, there was seawall construction and marine filling in the 3RS works area, as well as reclamation works for the Tung Chung New Town Extension concurrently in North Lantau waters. Since the major reclamation work for the 3RS Project concluded in 2021, some level of recovery would be expected, and some early signs of that appear to be evident in the data (despite the drop in numbers in 2025). However, several additional years of similar survey effort will be needed to examine this issue thoroughly, and we should not yet conclude that recovery has begun (nor that it has stopped). In fact, some time delay in seeing an increase in dolphin numbers would be reasonable to expect, and fluctuations in dolphin numbers appear to be a normal part of the recovery process. In particular, significant recovery would not be expected until sometime after the NLMP came into effect, which happened in late 2024.

Within NWL waters, CWDs have recently been mostly found in the western waters of the airport Island. The main concern is that dolphin numbers in NWL have decreased quite significantly in the past two decades, from around 100 to less than 10 (see Jefferson 2018; Jefferson et al. 2023). Some good news is that generally in WL and SWL dolphin numbers have remained similar to or above those in previous years and there are more sightings in NWL in 2025 compared to 2024. Past decreases suggested that construction activities in other areas of western Hong Kong waters (which, besides the 3RS works, includes IWMF works at Shek Kwu Chau) and other factors that are affecting dolphins north of Lantau Island may also be affecting their use of the waters south and west of Lantau Island. The potential for cumulative and far-ranging impacts from projects in specific areas is not well understood and should be a focus of future monitoring efforts covering broader Hong Kong waters and further afield. This would be a particularly acute concern for WL, which is known to represent the highest-density area for CWDs (and has been the highest since monitoring efforts began in the mid-1990s) and although not heavily impacted by marine construction in the past few years, the area has nonetheless shown evidence of a decrease in CWD numbers between 2019 and 2022, followed by a rebound in 2023 and 2024. The cause of this decline is not yet understood, and although there is a rebound during some of the recent years, the abundance of CWDs in WL survey area should be closely monitored.

In earlier years, concerns had been expressed by some stakeholders that dolphin numbers in NWL may have decreased due to hypothesized negative impacts from the re-routing of high-speed ferries (HSFs) to the Speed Control Zone (SCZ) north of Lung Kwu Chau. The analysis covering the entire first year post-SCZ (2016) provided an estimated abundance of 15 dolphins for NWL (refer to the 2016 annual report). The estimate for 2017 for the same area was 14 dolphins. The 2018 estimate was substantially higher at 22 dolphins. Therefore, the drop in 2019 to 8 dolphins was not likely due to the effects of the SCZ, which had been in operation for several years, but was more likely due to relatively more construction works for the 3RS and concurrent activities (such as changes in overall vessel traffic) in NL waters, or due to other unknown reasons. This belief is further bolstered by the fact that daily HSF trips were down substantially to single-digits in 2020 to 2022, due to COVID-19 impacts, and yet CWD numbers continued to decrease. Whatever the reasons for the fluctuations in numbers of dolphins in the NWL area, there is still no evidence that the SCZ has had any negative impacts on the dolphins.

Concerns were expressed in the 3RS EIA about the potential impacts on the travel corridor/area between both the 3RS project Area and SCLKCMP, and between CWD hotspots in NWL, NEL and WL, and the concern on the effectiveness of implementing the SkyPier HSF route diversion in alleviating the impacts on CWD travelling areas. Increased CWD sightings from vessel surveys in NEL area during 2018 suggested that a slight rebound in the use of these travel areas by CWDs may have occurred; however, this increase did not continue in 2019-2025. HZMB impacts were likely most severe during the period from 2013 to 2016 when construction works were ongoing (a period which saw an overall decline in CWD numbers in Hong Kong – Jefferson 2018), and the increase in CWD numbers in 2018 may have been the initial stages of recovery from that period of more intensive HZMB construction impacts. It is likely that the 3RS construction works and other concurrent activities in NL waters in 2019 onwards may have caused dolphins to again move away from these areas, as predicted in the 3RS EIA (Section 13.9.2). Nevertheless, it is noted that previous experience suggests that when construction is completed, and now that the new marine park has gone into effect, a rebound in numbers can again be expected (see Jefferson 2018). Data since 2018 indicate that the travelling areas are still being used, although at a lower level. It should also be kept in mind that dolphins tend to move through these areas relatively quickly and do not generally spend as much time milling as they do in the main foraging/socialising areas, which may further reduce the chance of dolphin sightings.

Photo-identification

Regarding the results of photo-identification work, a total of 98 CWD individuals were identified for altogether 242 times from all sightings in 2025, with 52 individuals (around 53.1%) sighted more than once. Amongst the 52 individuals that were re-sighted more than once in 2025, 31 individuals showed cross-area movement between survey areas. This accounted for about 31.6% of all 98 identified individuals in 2025. There were dolphins showing cross-area movement either between NWL-WL and WL-SWL but none showing cross-area movement between NWL-SWL except one individual namely WLMM065 which occurred in all three main survey areas (WL, SWL and NWL) in 2025. After a remarkable increase in cross-area movement involving NWL from eight individuals in 2020 to 21 individuals in 2021 followed by a drop to 12 individuals in 2022, the number of identified individuals with cross-area movement involving NWL slightly increased to 15 individuals in 2023. However, such increase did not continue in 2024 (six individuals) and dropped slightly to five individuals in 2025. The most frequently re-sighted animals in 2025 were SLMM003 which was sighted 12 times, followed by WLMM114 which was re-sighted 10 times. Nine identified dolphins were considered as year-round residents of Hong Kong waters in view of their occurrence pattern in all seasons for recent consecutive years.

Moreover, approximately 100 CWD individuals were successfully identified each year in Hong Kong's western waters in the past five years between 2021 and 2025, with annual totals ranging from 98 to 116 individuals. In addition, between 12 and 18 newly identified individuals were added to the photo-identification catalogue each year. These results indicate that Hong Kong's western waters continue to be regularly used by a substantial number of dolphins, with over 100 individuals recorded annually as part of their home ranges during the past five years. The continuous recruitment of newly identified individuals also suggests ongoing exchange and connectivity with the broader Pearl River Estuary population. During the same period, 24 to 29 sightings of mother–calf pair(s) were recorded annually, indicating that Hong Kong’s waters continue to serve as important nursery habitat for the species, supporting both calf rearing and recruitment within the wider Pearl River Estuary population.

Voluntary Supplementary Surveys by Passive Acoustic Monitoring

For better analysis of any rebound/changes of CWDs using the waters around the 3RS Project area, AAHK initiated the conduct of rebound surveys by means of PAM since 2020 to acquire extra CWD data. The Rebound Surveys were conducted by deployment of PAM devices called F-PODs, at seven locations around the waters of AW, SCLKCMP, BMP and NLMP (see Figure 1 of Appendix E.1). The Rebound Survey results indicated an overall increasing trend in dolphin acoustic detections in NWL waters from 2023 to 2025 after the completion of 3RS reclamation and marine works (Figure 2 of Appendix E.1), providing supplementary evidence that CWD usage in this area may be higher than suggested by vessel‑based abundance estimates alone.

As presented in Figure 3 of Appendix E.1, a notable increase in detections was recorded at the two locations in Airport West waters in 2025 (i.e. Location C and Location E), with overall mean daily DPM [2] of 14.2, overall DPD%[3] of 70%, indicating the continued use of the western waters of HKIA by CWDs. Meanwhile, detections at the three locations near Sha Chau waters (i.e. Locations A, D and A5) declined sharply in 2023, followed by a slight downward trend in subsequent years. Despite this reduction, dolphin DPM in Sha Chau waters remained relatively high. In addition, two potential overlapping acoustic events and vessel survey sightings were recorded in NWL, further supporting the presence of sustained dolphin activity in this area. In contrast, relatively low levels of acoustic activity were observed at the two stations in Airport East waters throughout the period from 2022 to 2025.

Overall, the dolphin DPM recorded in winter was the highest among all solar seasons, accounting for around 55% of the total dolphin DPM of Year 2025.

As shown in the Figure 4 of Appendix E.1, The Rebound Survey also revealed a pronounced diel pattern, with peak dolphin detections occurring predominantly during night‑time hours (e.g. approximately 42% detections in Year 2025 were recorded between 19:00 and 00:00; while 37% detections were recorded between 01:00 and 08:00), highlighting an important limitation of conventional vessel surveys, which restricted to daytime periods that allows visual observations. As such, vessel‑based monitoring under the 3RS EM&A programme may underestimate actual CWD usage in NWL, particularly during periods when dolphins’ nocturnal activity is pronounced.

Supplementary Information on CWDs Observations

Eco‑tours organised by AAHK between May 2025 and March 2026 provide a source of supplementary information on CWD activity. The eco-tours recorded 305 dolphins in a total of 35 trips in waters west of the airport and off West Lantau, in which there were seven sightings made in waters west of the airport and to the north of HZMB. These figures represent the total number of encountered dolphins and may include repeated individuals. Among the 305 dolphins sighted, 20 were calves (including UC and UJ). While these observations are derived from non‑systematic survey effort and are therefore not directly comparable with vessel‑based monitoring data, they provide supplementary evidence that CWDs continue to utilise western Hong Kong waters including west of the HKIA in NWL.

2.5.3 Conclusions of CWD Monitoring Results

With reference to the aims of operation phase CWD monitoring described in the EM&A Manual (Section 10.2.1.2-4), the key findings of CWD monitoring in 2025 are summarised as follows.

Effects on the Potential Shift in CWD Travelling Areas and Habitat Use

The last few years of monitoring data indicate an increase in overall CWD population, but mixed trends in use of areas within Hong Kong waters in 2024 and 2025, as compared to the previous years. The main area of increased use was West Lantau, which showed a substantial increase from the previous years, but a decrease in 2025. SWL also showed an increase from 5 to 15, and then a decrease in 2025. In contrast, CWD abundance in North Lantau waters (i.e., NWL and NEL survey area) remained consistently low (e.g. approximately 1 individual) in recent years (2023–2025), with no evident rebound in the areas observed in 2025 despite the designation of the NLMP in late 2024. As expected and predicted in the 3RS EIA, dolphins likely shifted their activities away from the 3RS construction activities as well as the increasing marine works for the Tung Chung New Town Extension project in 2019-2021. Nevertheless, they still used Hong Kong’s western waters (primarily SWL and WL) for important ecological activities such as foraging and resting, despite the disturbance. Whether a possible increase observed from 2021-2024 indicates the beginning of a long-term dolphin recovery in Hong Kong awaits more years of similarly-gathered data.

Effectiveness of the HSF Speed and Routing Restrictions to the CWDs

There are 10 years of data from the period since the SCZ was implemented, and the information available from both the vessel-based and the past land-based monitoring indicates that dolphin use of the NWL area has fluctuated from year to year (ranging from 1 to 22 dolphins), with a period of initial increase after the SCZ was put into effect. Due to COVID-19 effects, 2020, 2021 and 2022 were years of significantly decreased HSF activity in general, including in the SCZ area, and yet there was still a reduction in the use of NWL. Therefore, the evidence suggests that the SCZ is not impacting dolphin use of this area, and at the same time, is likely reducing the chances of dolphins being hit by vessels travelling at high speed. Daily SkyPier HSF trips resumed in 2023 and 2024 (refer to Section 2.9 and Table 2.19), while the dolphin abundance in NWL fluctuated between 2022 and 2024. Observations in 2024-2025 are still in line with those previous assessments.

Waters around Lung Kwu Chau have historically been a significant year-round habitat, especially for foraging, though 2020 saw a very large decline in use of this area by CWDs. There is no evidence that the observed decline in dolphin use of the HSF SCZ around Lung Kwu Chau was due to ferries being re-routed to that area with slower speeds at the end of 2015. The decline in numbers of dolphins in NWL area is not considered to be linked to HSF re-routings and the SCZ.

Trends in Long Term Monitoring Data

Based on vessel surveys conducted between 2020 and 2025, the estimated overall abundance of CWDs in Hong Kong waters was 32, 34, 35, 40, 60 and 30 individuals, respectively. These data indicate a gradual increase in abundance between 2021 and 2024, followed by a decline in 2025. Despite the increase observed in recent years, CWD use of Hong Kong waters remains substantially lower than levels recorded in the early 2000s.

Given the long lifespan and low reproductive rate of CWDs, short‑term fluctuations in abundance, such as the decline observed in 2025 following higher values in preceding years, are likely to reflect inter‑annual variation in distribution or response to environmental conditions (in this case potentially affected by the active stormy tropical-cyclone year in Hong Kong in 2025) rather than true population‑level change. It should be noted that abundance estimates of CWDs in Hong Kong waters have historically shown considerable inter‑annual variability since the early 2000s. Continued long‑term monitoring using consistent methodologies is therefore essential to determine whether the recent increase represents a sustained recovery trend or natural variability in habitat use over time.

West Lantau waters are still being used as the most important habitat in Hong Kong, as has been the case since CWD monitoring in Hong Kong started in 1995/1996. The increase of CWDs abundance in NWL in 2023 did not continue in 2024 or 2025. The low CWD abundance in NWL in 2024 and 2025 should not be interpreted as evidence of any long-term trend in NWL, as the overall dolphin abundance in Hong Kong waters has gone up considerably through 2024 and the supplementary information from Passive Acoustic Monitoring (PAM) findings exhibited more dolphin acoustic activities in NWL area in 2024 and 2025 compared with 2023.

While CWD abundance estimates derived from vessel surveys in NWL increased between 2020 and 2023 (estimated at 1, 4, 3 and 4 individuals respectively), a decline was recorded in 2024 and 2025 (with abundance estimated at 1 in both years). In contrast, PAM findings in 2025 exhibited an overall increasing trend in dolphin acoustic activity compared with 2023 and 2024, with detection levels remaining similar or slightly elevated across most PAM stations. This apparent discrepancy suggests that dolphins may have continued to use North Lantau waters on a regular basis despite lower abundance estimates derived from daytime surveys. Compared with previous years, increases in acoustic activity suggests a possible rebound or redistribution of CWD presence within North Lantau waters following the operation of the 3RS and the designation of the NLMP.

Recommendations on Future Monitoring for CWD Distribution

Taken together, the PAM results showing overall increasing detection of dolphin activities in NWL since 2024 with a marked diel pattern in night-time, provide indirect but independent evidence that the apparently low CWD abundance estimated for NWL in 2024-2025 calculated solely based on visual line-transect data from day-time vessel surveys should be interpreted with caution. Continuous and integrated monitoring during the 3RS operation phase, particularly combining vessel‑based surveys with PAM, remains essential to elucidate longer‑term recovery trends and habitat use patterns of CWDs in North Lantau waters, where the NLMP and other marine ecology enhancement measures have been implemented.

Theodolite tracking data will not be gathered in the immediate future due to the low detection rates of CWDs by this monitoring method, resulting in a lack of adequate survey data for conducting a robust analysis. Thus, no assessment of CWD behaviour or fine-scale movement patterns in the waters north of LKC, which historically supports high levels of dolphin activity, are possible. Should there be an increase in numbers in these former theodolite tracking areas, particularly north off LKC, such observations from shore may be re-initiated by AAHK to facilitate important long-term comparisons of behavioural data, including further information on dolphin reactions to human activities (Piwetz et al. 2015; Würsig et al. 2016).

It is important to remember that dolphins shift around within their habitat from year to year, due to both natural and anthropogenic factors. Thus, short-term monitoring data of CWDs is insufficient to indicate the full picture of population decline or recovery. Dolphins live for many decades and thus long-term monitoring using consistent methods is needed over an extended period of time in order to evaluate the true conservation status of the CWD population and how its use of Hong Kong waters is being affected over time.

The CWD construction, post-construction phase and operation phase monitoring data so far appear to be generally consistent with findings of the ecological assessments completed during the 3RS EIA, which predicted significant negative impacts during construction, including from the physical loss of habitat due to the reclamation (EIA Report Section 13.9.1). No unexpected ecological impacts on CWDs have been identified, and the increase in abundance in 2021-2024 is encouraging (notwithstanding the decrease in 2025).

In the 3RS EIA and as reported in the last several Annual EM&A Reports, it was predicted that dolphins would shift away from portions of their home range experiencing intense human activities, and that appears to have been the case in 2020 when the estimated CWD abundance by 3RS construction phase CWD monitoring reached a low point (i.e. 32 dolphins) as seawall works and marine filling activities intensified. These impacts are anthropogenic disturbances and therefore are of conservation concern; however, they are likely temporary and reversible and previous studies have supported that dolphin numbers can be expected to recover over the long-term, after completion of works (assuming that the habitat is properly protected and still of adequate quality – Jefferson 2018). While the 2025 abundance estimate has again fallen, it is quite likely this reflects inter-annual variation. Operation phase CWD monitoring for the 3RS by vessel-based line transect method was completed in December 2025 (after the designation of NLMP in late 2024), with AAHK’s voluntary CWD monitoring, including vessel survey and Rebound Survey continued in 2026 with focus on the North Lantau waters until around 2030 to monitor the trends in dolphin abundance and distribution over this longer period. The Rebound Survey is an additional AAHK initiative for CWD monitoring beyond statutory requirements and this monitoring effort is expected to facilitate an evaluation of impacts over time and will help determine if the Hong Kong CWD population stabilizes or increases in abundance in the future. An increase in numbers of Hong Kong CWDs is desirable for the long-term health of this population.

At this stage of the 3RS Project, all recommended mitigation measures have been implemented and although impacts were expected and have occurred, these appear to be temporary and within previously predicted patterns. As land formation was completed in the first quarter of 2023, and the NLMP was designated and came into effect on 1 November 2024, the expectation is that the CWD population will stabilize or increase in the coming years. Patterns of CWD abundance will be kept under review over the next few years, as AA’s CWD Rebound Survey monitoring continues in the future.

Although abundance estimates derived from line-transect surveys in Hong Kong waters are typically used as an indicator of local population status, it is important to recognize that the dolphins occurring in Hong Kong represent only a portion of the much larger Pearl River Estuary (PRE) population. Current understanding suggests that the PRE population comprises approximately 2,000 individuals distributed across a broad geographic range extending through the waters of Hong Kong, Macao, Zhuhai and the western coast of the Guangdong Province. Other photo-identification and movement studies have demonstrated that many individuals regularly move across administrative boundaries and utilize habitats both inside and outside Hong Kong waters (Chen et al, 2010, Hung and Jefferson, 2004). Consequently, fluctuations in dolphin abundance recorded within Hong Kong may not necessarily reflect equivalent changes in the size of the entire PRE population, as local changes can also result from shifts in habitat use, ranging patterns, and distribution. Hong Kong therefore forms an important component of the Eastern PRE subpopulation but should be viewed within the broader context of the interconnected PRE metapopulation when evaluating population status and long-term conservation outcomes.

International Cetacean Expert’s Observation and Recommendations from the 3RS Project Long-term Monitoring Effort

In terms of the long-term conservation and management of the CWD population and specifically that portion that uses Hong Kong waters, it is important for numbers to stabilize now that marine construction has completed, as the evidence suggests both that dolphins are using Hong Kong waters less intensively and that the overall population is declining (see Huang et al. 2012; Jefferson 2018; Jefferson et al. 2023). The intensive evaluation of construction methods that was undertaken in the EIA process for this project leading to lower impact construction approaches and methods that are less harmful to dolphins, including the use of Deep Cement Mixing for site stabilization should be seen as an exemplary approach to be emulated and amplified in future impact assessments and on any future large projects in Hong Kong.

A major goal for Hong Kong (primarily the Agriculture, Fisheries and Conservation Department) and Mainland Management Authorities should be to establish effective measures including, but not limited to, protection of critical foraging and breeding habitat, as well as important travel routes for the dolphins. Most importantly, the area along the entire west coast of Lantau Island has consistently been used as prime habitat by CWDs for the past several decades, but unfortunately numbers there have declined between 2019 and 2022 (and again in 2025). This region has been confirmed by the current 3RS project monitoring efforts to remain as the most important habitat for dolphins in Hong Kong, based on densities of CWD use. This has also been confirmed by the recent computer modelling study of dolphin habitat in Hong Kong (Jefferson et al. 2023), but most of the area still remains unprotected, with the exception of the Southwest Lantau Marine Park, which was designated in 2020. The formation of Marine Parks/ Reserves for CWDs in this area should be seen as an extremely high priority for protecting critical dolphin habitat for the future of CWDs in Hong Kong. If it is used properly, the knowledge learned from the 3RS Project, as well as the funding support and attention given the CWDs from this project (e.g., through the Marine Ecology Enhancement Fund), can be very helpful for management authorities in achieving the important long-term goal of stabilizing the CWD population, and ensuring its long-term health and survival.

2.5.4 Site Audit for CWD-related Mitigation Measures

During the reporting period, teams of at least two dolphin observers were deployed by contractors for continuous monitoring of the Dolphin Exclusion Zone (DEZ) for armour rock laying works in accordance with the DEZ Plan from May to December 2025. No dolphins or other marine mammals were observed within the DEZs during this period. These contractors’ records were audited by the ET during site inspections.

According to Section 10.6.2.2 of the Updated EM&A Manual, audits of HSFs implementation measures and Spill Response Plan implementation measures were conducted once every three months and every six months respectively for one year upon operation of 3RS.

For HSFs implementation measures, the first audit was conducted in February 2025, followed by subsequent audits in May, August and November 2025.

For Spill Response Plan implementation measures, the first audit was conducted in May 2025 and the second audit was conducted in November 2025.

The one-year audit for both HSFs implementation measures and Spill Response Plan implementation measures has been completed, with no specific findings identified throughout the audit period.

2.6 Sewage Flow Monitoring

In accordance with Section 6.2.1.1 of the Manual, the annual sewage flow monitoring commenced in June 2021, with the objective of informing the timing for initial planning of sewer upgrading works, Given that AAHK has begun planning for construction phase, the annual monitoring was concluded in December 2022. Details of the daily average flows data are presented in Annual EM&A Report No. 7.

In accordance with Section 6.2.1.2 of the Manual, the routine monitoring of hydrogen sulphide (H₂S) levels for the sewerage system of 3RS commenced after the commissioning of the 3RS on 28 November 2024.

2.7 Landscape and Visual Mitigation Measures

Implementation of applicable landscape and visual mitigation measures (reference to the environmental protection measures CM1 – CM10 in Appendix C) was monitored in accordance with the Manual and the Landscape & Visual Plan. All measures undertaken by both the contractor and the landscape contractor during the construction phase and first year of the operation phase are audited by a landscape architect, as a member of the ET, on a regular basis to ensure compliance with the intended aims of the measures.

Site inspections and audits are undertaken as necessary in the construction and operation phases in accordance with the Monitoring Programme for Landscape and Visual as shown in Table 2.12. In case of non-conformity, specific recommendations will be made, and actions will be proposed in accordance with the Event and Action Plan as shown in Table 2.13. No non-conformities were recorded during the reporting period.

Table 2.12: Monitoring Programme for Landscape and Visual

Stage	Monitoring Task	Monitoring Report	Form of Approval	Frequency
Detailed Design	Checking of design works against the recommendations of the landscape and visual impact assessments within the EIA shall be undertaken during detailed design and tender stage, to ensure that they fulfil the intention of the mitigation measures. Any changes to the design, including design changes on site shall also be checked.	Report by AAHK / PM confirming that the design conforms to requirements of EP.	Approved by Client	At the end of the Detailed Design Phase
Construction	Checking of the contractor’s operations during the construction period.	Report on Contractor's compliance, by ET	Counter signature of report by IEC	Weekly
Establishment Works	Checking of the planting works during the twelve-month Establishment Period after completion of each batch of transplanting works.	Report on Contractor's compliance, by ET	Counter signature of report by IEC	Every two months
Long Term Management (10 year)	Monitoring of the long-term management of the planting works in the period up to 10 years after completion of each batch of transplanting works.	Report on Compliance by ET or Maintenance Agency as appropriate	Counter signature of report by Management Agency	Annually

Table 2.13: Event and Action Plan for Landscape and Visual

Event Action Level	Action
	ET	IEC	AAHK / PM	Contractor
Design Check	Check final design conforms to the requirements of EP and prepare report.	Check report. Recommend remedial design if necessary.	Undertake remedial design if necessary.
Non-conformity on one occasion	Identify source. Inform IEC and AAHK / PM. Discuss remedial actions with IEC, AAHK / PM and Contractor. Monitor remedial actions until rectification has been completed.	Check report. Check Contractor’s working method. Discuss with ET and Contractor on possible remedial measures. Advise AAHK / PM on effectiveness of proposed remedial measures. Check implementation of remedial measures.	Notify Contractor. Ensure remedial measures are properly implemented.	Amend working methods to prevent recurrence of non-conformity. Rectify damage and undertake additional action necessary.
Repeated Non-conformity	Identify source. Inform IEC and AAHK / PM. Increase monitoring frequency. Discuss remedial actions with IEC, AAHK / PM and Contractor. Monitor remedial actions until rectification has been completed. If non-conformity stops, cease additional monitoring.	Check monitoring report. Check Contractor’s working method. Discuss with ET and Contractor on possible remedial measures. Advise AAHK / PM on effectiveness of proposed remedial measures. Supervise implementation of remedial measures.	Notify Contractor. Ensure remedial measures area properly implemented.	Amend working methods to prevent recurrence of non-conformity. Rectify damage and undertake additional action necessary.
Note: For PM in Table 2.13, refers to Project Manager only.

2.7.1 The Implementation Status of the Environmental Protection Measures

The implementation status of the environmental protection measures is summarised below in Table 2.14. For trees which were managed by the Project during the reporting period, relevant measures have been implemented by Contracts 3508 and the works of 132kV Cable.

Table 2.14: Implementation Status of the Environmental Protection Measures

Landscape and Visual Mitigation Measures during Construction Implementation Status	Implementation Status	Relevant Contract(s) in the Reporting Period
CM1- The construction area and contractor’s temporary works areas shall be minimised to avoid impacts on adjacent landscape	The implementation of mitigation measures was checked by ET during weekly site inspection and clarified by the Contractors during the monthly Environmental Management Meetings. Implementation of the measures CM5, CM6 and CM7 by Contractors was observed.	All works contracts
CM2 – Reduction of construction period to practical minimum
CM3 – Phasing of the construction stage to reduce visual impacts during the construction phase
CM4 – Construction traffic (land and sea) including construction plants, construction vessels and barges shall be kept to a practical minimum
CM5 – Erection of decorative mesh screens or construction hoardings around works areas in visually unobtrusive colours
CM6 – Avoidance of excessive height and bulk of site buildings and structures
CM7 – Control of night-time lighting by hooding all lights and through minimisation of night working periods
CM8 – All existing trees shall be carefully protected during construction. Detailed Tree Protection Specification shall be provided in the Contract Specification. Under this specification, the Contractor shall be required to submit, for approval, a detailed working method statement for the protection of trees prior to undertaking any works adjacent to all retained trees, including trees in contractor’s works areas	Tree Protection Specifications have been provided in the relevant Contract Specifications respectively for implementation by the Contractors under the Project. The Contractors’ performance on the implementation of the trees maintenance and protection measures was observed and checked by the ET weekly during construction period.	3508, 132kV Cable
CM9 – Trees unavoidably affected by the works shall be transplanted where practical. A detailed Tree Transplanting Specification shall be provided in the Contract Specification, if applicable. Sufficient time for necessary tree root and crown preparation periods shall be allowed in the project programme	Tree Transplanting Specifications have been provided in the relevant Contract Specifications respectively for implementation by the Contractors under the Project where trees will unavoidably be affected by the construction works. The Contractors were required to submit Method Statements for tree transplanting prior to the transplanting works. Tree inspections were conducted by ET to check the tree transplanting works implemented by the Contractors on site. The Contractors’ performance on the implementation of trees maintenance and protection measures on transplanted trees was observed and checked by the ET bi-monthly during the 12-month establishment period after the completion of each batch of transplanting works. Long term management of the transplanted trees were currently monitored by ET annually.	3508
CM 10 – Land formation works shall be followed with advanced hydroseeding around taxiways and runways as soon as practical	The Contractor’s performance on the implementation of advanced hydroseeding works was observed and checked by the ET during the weekly site inspection.	-
OM7- Compensatory tree planting for all felled trees shall be provided to the satisfaction of relevant Government departments. Required numbers and locations of compensatory trees shall be determined and agreed separately with Government during the Tree Felling Application process under the relevant technical circulars.⁽¹⁾	The two batches of compensatory trees were planted and the bi-monthly site inspection for the 12-month establishment period was commenced. During the reporting period, the bi-monthly site inspection was undertaken in June, August, October and December 2023.	AAHK

Note:

AAHK is the management and maintenance agency of the compensatory trees. Tree Felling Application is not required for 3RS Project.

The 3RS Project is a mega project comprising a number of detailed design contracts and numerous construction works contracts at different stages of design and construction. The works areas would be taken up by different 3RS works contracts in stages as construction advanced. The landscape and visual elements associated with these contracts of the 3RS Project would also be designed and implemented in phases throughout the duration of the Project.

Since the EIA stage, the proposed tree treatments were adjusted to reflect updated baseline conditions, such as damage from typhoons, and the availability of more detailed design information for project buildings and infrastructure. These treatment figures were subsequently revised and incorporated into the latest Landscape and Visual Plan.

Environmental monitoring and audit work which included the auditing of contractor’s work in landscape and visual aspects such as tree preservation, protection and transplantation was implemented in accordance with the updated construction programme, the relevant requirements of the EP, the Updated EM&A Manual and the approved Landscape & Visual Plan.

The total number of retained trees, transplanted trees and to-be-transplanted trees under the management of Project are summarized in Table 2.15. The tree schedule updated as of the end 2025 is shown in Appendix G.

Table 2.15: Summary of the Number of Retained, Transplanted and To-be-transplanted Trees as of December 2025

Contract No.	Retained (nos.)	Transplanted (nos.)		To-be-transplanted (nos.)
Contract No.	Retained (nos.)	Establishment Period	Maintenance Period	To-be-transplanted (nos.)
3503⁽¹⁾	0	0	9	0
3508	21	0	12	0
3801⁽²⁾	0	0	5	0
132kV Cable	45	0	0	0
Grand Total	66	0	26	0

Note:

1. Contract 3503 was completed and the 9 transplanted trees, including T835, T836, T838, T812, T814, T815, T829, T830 and T831, were handed over to AAHK in February 2022.

2. Contract 3801 was completed and the 5 transplanted trees, including CT276, CT1253, CT1194, CT1794 and CT1795, were handed over to other management agencies. Details of the management agency are presented in Table 2.17.

Table 2.16 lists the affected tree ID together with the reasons for change of tree status between the tree schedules as of the end 2024 and the end 2025.

The total number of retained trees of the Project as of the end of 2025 was 66. Compared to 24 nos. of retained trees reported in the tree schedule as of the end of 2024, the change in number was due to the following reasons:

· The works of 132kV Cable commenced the maintenance of retained trees. (+52 nos.)

· Three retained trees under Contract 3508 were handed over to AAHK. (-3 nos.)

· Under the works of 132kV Cable, a total of seven trees were removed, comprising three trees due to Typhoon Whipa (-3 nos.), two trees due to Typhoon Ragasa (-2 nos.), and two trees due to tree mortality (-2 nos.).

Table 2.16: Summary of the Tree Status Changes between end 2024 and end 2025

Tree ID(s)	Contract	Status as of end 2024	Status as of end 2025	Remarks	Impacts to Total Tree Number
Section 5: T001, T002, T004, T007, T013, T014, T016, T017, T019, T020, T021, T023, T024, T025, T031, T045, T046, T057, T048, T054, T055, T056, T061, T064, T065, T066, T068, T069, T072, T075, T083, T084, T087, T089, T091, T094, T095, T098, T103, T104, T107, T112, T113, T126, T133, T134, T135, T140, T142, T146 & T148 Section 6: T136	132kV Cable	Retain	Retain	52 nos. of trees were maintained under the works of 132kV Cable starting from March 2025.	Retain: +52 nos.
T813, T833 & T834	3508	Retain	Retain	3 nos. of tree were handed over to AAHK in September 2025.	Retain: -3 nos.
Section 5: T023, T024 & T025	132kV Cable	Retain	Fell	3 nos. of tree were collapsed and removed in September 2025 due to Typhoon Whipa.	Retain: -3 nos.
Section 5: T064 & T095	132kV Cable	Retain	Fell	2 nos. of tree were removed in October 2025 due to Typhoon Ragasa.	Retain: -2 nos.
Section 5: T054 & T133	132kV Cable	Retain	Fell	2 nos. of tree were dead and removed in December 2025.	Retain: -2 nos.

In this reporting period, the cumulative total number of transplanted trees under the Project remained unchanged (i.e., 26) comparing to the previous reporting period. The details of transplanted trees are summarised in Table 2.17. Photos of the transplanted trees are presented in Table 2.18.

During the reporting period, the bi-monthly site inspections of compensatory trees under the 12-month establishment period were undertaken in January, March, April, May, July, August, September, October, November and December 2025.In addition, annual site inspections for the long term management period were undertaken in April and May 2025.

Table 2.17: Details of the Transplanted Trees

Tree ID	Transplant Date	Management Stage	Management Agency	Remarks
CT276	3 May 2018	Long Term Management period Jun 2019 – May 2028	Southern Landside Petrol Filling Station	Establishment Period was completed. Next inspection will be conducted in February 2026.
CT1253	4 May 2018	Long Term Management period Jun 2019 – May 2028	Southern Landside Petrol Filling Station
T835	22 Jan 2020	Long Term Management period Feb 2021 – Jan 2030	AAHK	Establishment Period was completed. The trees within the land parcel were acquired for construction of infrastructure. The trees were felled in 2023.
T836	13 Dec 2019	Long Term Management period Feb 2021 – Jan 2030	AAHK
T838	22 Jan 2020	Long Term Management period Feb 2021 – Jan 2030	AAHK
T812	21 Dec 2020	Long Term Management period Jan 2022 – Dec 2031	AAHK	Establishment Period was completed. Next inspection will be conducted in December 2026.
T814	20 Dec 2020	Long Term Management period Jan 2022 – Dec 2031	AAHK
T815	15 Dec 2020	Long Term Management period Jan 2022 – Dec 2031	AAHK
T829	18 Dec 2020	Long Term Management period Jan 2022 – Dec 2031	AAHK
T830	14 Dec 2020	Long Term Management period Jan 2022 – Dec 2031	AAHK
T831	19 Dec 2020	Long Term Management period Jan 2022 – Dec 2031	AAHK
T1493	6 Jul 2021	Long Term Management period Aug 2022 – Jul 2031	Contract 3508	Establishment Period was completed. Next inspection will be conducted in July 2026.
T1494	6 Jul 2021	Long Term Management period Aug 2022 – Jul 2031	Contract 3508
T1495	10 Jul 2021	Long Term Management period Aug 2022 – Jul 2031	Contract 3508
T1496	5 Jul 2021	Long Term Management period Aug 2022 – Jul 2031	Contract 3508
T1497	5 Jul 2021	Long Term Management period Aug 2022 – Jul 2031	Contract 3508
T1498	29 Jun 2021	Long Term Management period Aug 2022 – Jul 2031	Contract 3508
T1499	29 Jun 2021	Long Term Management period Aug 2022 – Jul 2031	Contract 3508
T1500	30 Jun 2021	Long Term Management period Aug 2022 – Jul 2031	Contract 3508
T1501	30 Jun 2021	Long Term Management period Aug 2022 – Jul 2031	Contract 3508
T1502	5 Jul 2021	Long Term Management period Aug 2022 – Jul 2031	Contract 3508
T1503	6 Jul 2021	Long Term Management period Aug 2022 – Jul 2031	Contract 3508
T1504	24 Jun 2021	Long Term Management period Aug 2022 – Jul 2031	Contract 3508
CT1194	4 May 2018	Long Term Management period Jun 2019 – May 2028	Southern Landside Petrol Filling Station	Establishment Period was completed. Uprooted and collapsed due to Typhoon Higos on 18 August 2020. Tree removal was conducted as recommended by tree specialist of the contractor of Southern Landside Petrol Filing Station.
CT1794	3 May 2018	Long Term Management period Jun 2019 – May 2028	AsiaWorld-Expo	Establishment Period was completed. The tree within the land parcel was acquired by the government for construction of emergency hospital to handle COVID19 pandemic at AsiaWorld-Expo. The tree was felled in late 2020.
CT1795	3 May 2018	Long Term Management period Jun 2019 – May 2028	AsiaWorld-Expo	Establishment Period was completed. The tree within the land parcel was acquired by the government for construction of emergency hospital to handle COVID19 pandemic at AsiaWorld-Expo. The tree was felled in late 2020.

Table 2.18: Photos of the Existing Transplanted Trees in the Reporting Period

Under 10-year Long-term Management (Jun 2019 – May 2028):

CT276		CT1253
Under 10-year Long-term Management (Jan 2022 – Dec 2031):

T812	T814		T815

T829	T830		T831

Under 10-year Long-term Management (Aug 2022 – Jul 2031):

T1493	T1494	T1495

T1496	T1497	T1498

T1499	T1500	T1501

T1502	T1503	T1504

2.8 Environmental Site Inspection

Site inspections of the construction works were carried out on a weekly basis to monitor the implementation of proper environmental pollution control and mitigation measures for the Project. Bi-weekly site inspections were also conducted by the IEC. Besides, ad-hoc site inspections were conducted by ET and IEC if environmental problems were identified, or subsequent to receipt of an environmental complaint, or as part of the investigation work. During the reporting period, ET conducted 822 sessions of site inspections and 155 sessions of ad-hoc site inspections. These site inspections provided a direct means to reinforce the specified environmental protection requirements and pollution control measures in construction sites.

During site inspections, environmental situation, status of implementation of pollution control and mitigation measures were observed both within the site area as well as outside the project sites which was likely to be affected, directly or indirectly, by the site activities. Environmental documents and site records, including waste disposal records, maintenance records of environmental equipment, and relevant environmental permits and licences, were also checked on site. Observations were recorded in the site inspection checklist and passed to the contractor together with the appropriate recommended mitigation measures where necessary in order to advise contractors on environmental improvement, awareness and on-site enhancement measures. The observations were made with reference to the following information during the site inspections:

● The EIA and EM&A requirements;

● Relevant environmental protection laws, guidelines, and practice notes;

● The EP conditions and other submissions under the EP;

● Monitoring results of EM&A programme;

● Works progress and programme;

● Proposal of individual works;

● Contract specifications on environmental protection; and

● Previous site inspection results.

Good site practices were observed in site inspections during the reporting period. Advice was given when necessary to ensure the construction workforces were familiar with relevant procedures, and to maintain good environmental performance on site. Regular toolbox talks on environmental issues were organized for the construction workforces by the contractors to ensure understanding and proper implementation of environmental protection and pollution control mitigation measures.

Summary of implementation status of the environmental mitigation measures for the construction phase of the Project during the reporting period is provided in Appendix C.

2.9 Audit of the SkyPier High Speed Ferries

The Marine Travel Routes and Management Plan for High Speed Ferries of SkyPier (the SkyPier Plan) was submitted to the Advisory Council on the Environment (ACE) for comment and subsequently submitted to and approved by EPD in November 2015 under EP Condition 2.10. The approved SkyPier Plan is available on the dedicated website of the Project. In the SkyPier Plan, AAHK has committed to implementing the mitigation measure of requiring HSFs of SkyPier travelling between HKIA and Zhuhai / Macau to start diverting the route with associated speed control across the area, i.e. SCZ, with high CWD abundance. The route diversion and speed restriction at the SCZ have been implemented since 28 December 2015. The IEC has also performed audit on the compliance of the requirements as part of the EM&A programme.

According to the approved SkyPier Plan, dolphin habitat index was reviewed in the reporting period based on findings of the AFCD’s marine mammals monitoring report 2024-25 and historical dolphin density records. Grids for dolphin hotspots remained largely unchanged, thus the HSF route diversion arrangement remained unchanged.

Due to the operational needs, the SkyPier HSF services to/from Zhuhai has been suspended since 25 March 2020. In total, 6 ferry movements between HKIA SkyPier and Macau were audited in the reporting period. All 6 audited ferry movements travelled through the SCZ with average speeds of 15 knots or below, complying with the SkyPier Plan. The latest summary of key audit findings in the reporting period is presented in Table 2.19.

Table 2.19: Summary of Key Audit Findings against the SkyPier Plan

Key Audit Findings	Jan-25	Feb-25	Mar-25	Apr-25	May-25	Jun-25	Jul -25	Aug-25	Sep-25	Oct -25	Nov-25	Dec-25
Total number of HSF movements recorded and audited for HSFs to/from Macau	6	0	0	0	0	0	0	0	0	0	0	0
Use diverted route and enter / leave SCZ through Gate Access Points	6	0	0	0	0	0	0	0	0	0	0	0
No. of SkyPier HSFs in compliance with average speed within 15 knots in SCZ	6	0	0	0	0	0	0	0	0	0	0	0

Source: Excerpted from Monthly EM&A Report No. 109 – 120.

Remarks: No HSF services to/from Macau from Feb to Dec 2025.

2.10 Audit of the Construction and Associated Vessels

The audit of construction and associated vessels in accordance with the Marine Travel Route and Management Plan for Construction and Associated Vessel (MTRMP-CAV) has been conducted since August 2016. The ET has audited relevant information including Automatic Identification System (AIS) data, vessel tracks and other relevant records provided by the contractors to ensure that the contractors were fully complied with the requirements of the MTRMP-CAV. The Maritime Surveillance System (MSS) was launched in March 2017 and has automatically recorded deviation cases such as speeding, entering no entry zone, and not travelling through designated gates. The ET conducted checking to ensure the MSS recorded all deviation cases accurately.

The updated MTRMP-CAV was approved by EPD on 16 May 2025 under EP Condition 2.9. Following its implementation, the MSS continued to automatically record any deviations, while the ET conducted bi-weekly audits of relevant records up to May 2025. From June 2025 onwards, the ET audited construction and associated vessels activities based on the marine travel routes records submitted by the contractors and the ET also conducted separate monthly checks of construction and associated vessels travel routes. Deviation cases such as speeding, vessel not turning on AIS and berthing within the NLMP were identified, and all the relevant contractors were reminded to adhere to the requirements outlined in the MTRMP-CAV. The contactors continued to submit 3-month rolling vessel plans for construction vessel activities to AAHK in order to help maintain the number of construction vessels at a practicable minimum. The IEC also carried out compliance audits as part of the EM&A programme.

A total of one skipper training workshop was held by ET during the reporting period with one skipper / captain of construction vessels associated with the 3RS contracts to familiarise him with the predefined routes, provide general education on local cetaceans, outline guidelines for minimising adverse water quality impact, detail the required environmental practices / measures and safety measures for operating construction and associated vessels in the presence of CWDs. In addition, five skipper training workshops were held by contractors’ Environmental Officers with seven skippers / captains and competency tests were conducted subsequently with the trained skippers / captains by ET to access the trainees’ understanding and readiness. Furthermore, the ET participated in Marine Management Liaison Group meetings to assist in resolving any marine-related issues encountered during the Project.

2.11 External Stakeholder Engagement

In accordance with the EP’s requirements of setting up Community and Professional Liaison Groups, the AAHK has been continuing to proactively reach out to a wide spectrum of external stakeholders to update them on the environmental aspects of the Project and to seek their insights and views. There were continuous exchanges with the local communities, relevant professionals, experts, and other stakeholders. Below are highlights of the engagement activities held in 2025.

2.11.1 Community Liaison Groups

In order to enhance transparency and communication with the community in a proactive way, five Community Liaison Groups (CLGs) were set up in 2012 in the neighbouring districts of HKIA, namely Islands, Kwai Tsing, Shatin, Tsuen Wan and Tuen Mun. The CLGs are comprehensive platforms for the AAHK to update the community leaders about the detailed design, progress of construction and operation, and environmental monitoring and audit results of the Project, and listen to their views on various topics related to HKIA and the Project, including environmental matters. The AAHK also leverages on the CLGs to exchange views with the community on the latest airport developments, hence enhancing airport services and helping to contribute to the betterment of these districts. The CLGs have a total of about 150 members involving district councillors and community leaders. In 2025, two meeting cum airport visit were held in June and December. Project information including the latest development of the 3RS project, environmental monitoring and audit results, and details on the implementation of environmental and ecological enhancement measures were presented in the meetings.

2.11.2 Professional Liaison Group and Green Non-Governmental Organizations

The Professional Liaison Group, comprising 19 members of relevant professionals and experts, was set up to enhance transparency and communication, as well as enquiries and complaints-handling on all environmental issues related to the Project; and to promote community cooperation and participation and implementation of suitable local environmental enhancement works that are included in the Environmental Permit. In 2025, a meeting cum eco-tour in the West Lantau waters was held in May.. Project information including the latest development of the 3RS Project, environmental monitoring and audit results, and details on the implementation of environmental and ecological enhancement measures were presented in the meeting.

Roundtable meetings with Green Non-Governmental Organizations (NGOs) were proactively arranged to facilitate exchanges on environmental issues related to the Project. Updates of the Project, and details on the implementation of environmental and ecological enhancement measures were shared with the participants. In 2025, a meeting cum eco-tour in the West Lantau waters was held in May.

2.11.3 Fishermen Liaison

In an effort to deepen outreach to the fishermen community, a dedicated Fishermen Liaison Group was set up in November 2016 to share updates on environmental matters and progress of construction and operation with the chairmen and leaders of fishermen groups and associations. In 2025, a meeting was held in June.

2.11.4 Other Stakeholders

The AAHK submitted an information paper to the Legislative Council Panel on Economic Development in March 2025, providing an update on the commissioning of the 3RS project and post-commissioning airport operations. Furthermore, the AAHK submitted a paper to the Advisory Council on the Environment (ACE) in July 2025 reporting an update on the implementation of the environmental mitigation and enhancement measures in association with the 3RS Project.

To encourage two-way communications with stakeholders and the community, a dedicated telephone hotline and email has been set up since December 2015. Six enquiries were received via the telephone hotline and twenty-six enquiries were received via the dedicated email in 2025.

2.12 Review of the Key Assumptions Adopted in the EIA Report

With reference to Appendix E of the Manual, it is noted that the key assumptions adopted in approved EIA Report for the construction phase are still valid and no major changes are involved. The environmental mitigation measures recommended in the approved EIA Report remain applicable and shall be implemented in undertaking construction works for the Project.

2.13 Key Environmental Issues for the Coming Reporting Period

The key environmental issues for the Project in the coming reporting period are expected to be associated with construction activities including:

· Generation of dust from construction works and stockpiles;

· Noise from operating equipment and machinery on-site;

· Generation of site surface runoffs and wastewater from activities on-site;

· Sorting, recycling, storage and disposal of general refuse and construction waste;

· Reuse of treated marine sediments from piling and excavation works; and

· Management of chemicals and avoidance of oil spillage on-site.

The implementation of required mitigation measures by the contractors will be monitored by the ET.

3 Report on Non-compliance, Complaints, Notifications of Summons and Prosecutions

3.1 Compliance with Other Statutory Environmental Requirements

During the reporting period, environmental related licenses and permits required for the construction activities were checked. No non-compliance with environmental statutory requirements was recorded.

3.2 Analysis and Interpretation of Complaints, Notification of Summons and Status of Prosecutions

3.2.1 Complaints

Three environmental complaints were received during the reporting period, all of which were related to air quality. The ET conducted investigations for each complaint in accordance with the Manual and the Complaint Management Plan. A summary of the complaints and corresponding analysis is presented in Appendix F.

3.2.2 Notifications of Summons or Status of Prosecution

No notification of summonses or prosecutions were received in the reporting period.

3.3 Cumulative Statistics

Cumulative statistics on exceedance, non-compliance, complaints, notifications of summons and status of prosecutions are summarized in Appendix F.

4 Conclusion and Recommendation

The new North Runway was commissioned in November 2022. Following the completion of reconfiguration works on the Centre Runway, the 3RS was commissioned on 28 November 2024. Meanwhile, the expanded Terminal 2 (T2) is being launched in phases, with the first phase of operation commenced on 23 September 2025.

During the reporting period from 1 January 2025 to 31 December 2025, the EM&A programme has been implemented in accordance with the Manual of the Project. The EM&A works carried out during the reporting period included construction dust and noise measurements, waste monitoring, and landscape and visual monitoring and environmental site inspections for the Project’s construction works.

The monitoring results in relation to the construction dust, construction noise and construction waste did not trigger their corresponding Action or Limit Levels during the reporting period.

The excavation and treatment of marine sediment were completed in February 2025. The remaining treated marine sediment is stockpiled properly at 3RS Project site area, awaiting backfilling.

A total of around 5352.7 km survey effort was conducted for the vessel line-transect monitoring for CWDs during the 12-month operation phase monitoring period. A total of 166 groups of 466 CWDs were sighted in NWL, AW, WL and SWL survey areas. No CWDs were recorded in the NEL survey area. Overall abundance of CWD in Hong Kong western waters was estimated at 30 dolphins in 2025 from line-transect analysis. According to the Updated EM&A Manual, all CWD monitoring under the EM&A requirement was completed.

On the implementation of DEZ Plan, dolphin observers were deployed by the contractors for continuous monitoring of the DEZ for armour rock laying works in accordance with the DEZ Plan. Trainings for the dolphin observers on the implementation of MMWP and DEZ monitoring were provided by the ET prior to the aforementioned works. As for DEZ monitoring records, no dolphins or other marine mammals were observed within the DEZs in this reporting period.

Site inspections and audits were undertaken in accordance with the monitoring programme for landscape and visual impacts during construction and establishment works phases. No non-conformities were recorded during the reporting period.

A total of 6 ferry movements between HKIA SkyPier and Macau were audited in the reporting period. All audited movements travelled through the SCZ with average speeds of 15 knots or below, complying with the SkyPier Plan.

The audit of construction and associated vessels has been conducted since August 2016. The updated MTRMP-CAV was approved by EPD on 16 May 2025 under EP Condition 2.9. Following its implementation, the MSS continued to automatically record any deviations, while the ET conducted bi-weekly audits of relevant records up to May 2025. From June 2025 onwards, the ET audited construction and associated vessels activities based on the marine travel routes records submitted by the contractors and the ET also conducted separately monthly checks of the construction and associated vessels travel routes. Deviation cases such as speeding, vessel not turning on AIS and berthing within the NLMP were identified, and all the relevant contractors were reminded to adhere to the requirements outlined in the MTRMP-CAV. A total of one skipper training workshop was conducted by the ET during the reporting period with captains of construction vessels associated with 3RS contracts. Another five skipper training workshops were held by contractors’ Environmental Officers and competency tests were conducted subsequently with the trained captains by ET.

AAHK strives to be highly transparent in its works and continues to engage with stakeholders through meetings and communications. Having said that, the dedicated 3RS Project website provides up-to-date information including EM&A results, updated plans and submissions in accordance with requirements in the EP, materials of the liaison group meetings, flyers introducing environmental initiatives of the 3RS Project, as well as information on the status and operation of the Marine Ecology Enhancement Fund and the Fisheries Enhancement Fund.

Overall, the recommended environmental mitigation measures, as included in the EM&A programme, have been effectively implemented during the reporting period. Also, the EM&A programme implemented by the ET has effectively monitored the construction activities and ensured the proper implementation of mitigation measures.

[1] The Manual is available on the Project’s dedicated website (accessible at: http://env.threerunwaysystem.com/en/index.html).

[2] DPM = detection positive minutes (minutes with one or more dolphin detection)
Mean daily DPM = DPM / total logged days
Overall mean daily DPM of multi-Locations = Sum of mean daily DPM at each Location

[3] DPD = detection positive days (days with one or more dolphin detections);
For generating the overall DPD for multi-Locations, when more than one Location recorded DPD on the same day, it counts ONE DPD for the day;
"DPD%" is the detection positive days as a percentage of total logged days.