A1. The Project, Design, Build and Operate First Stage of Tseung Kwan O Desalination Plant (TKODP), is a Designated Project under the Environmental Impact Assessment Ordinance (Cap. 499) (EIAO) and is currently governed by a Further Environmental Permit (EP No. FEP - 01/503/2015/B) for the construction and operation of the Contract.

A2. In accordance with the Environmental Monitoring and Audit (EM&A) Manual for the Contract, EM&A works for marine water quality, noise, waste management and ecology should be carried out by Environmental Team (ET), Acuity Sustainability Consulting Limited (ASCL), during the construction phase of the Contract.

A3. This is the 51st Monthly EM&A Report, prepared by ASCL, for the Contract summarizing the monitoring results and audit findings of the EM&A programme at and around Tseung Kwan O Area 137 (TKO 137) during the reporting period from 1 May to 31 May 2024.

A4. The EM&A programme for this contract has covered environmental monitoring on construction noise level at selected NSRs and Contractor’s environmental performance auditing in the aspects of construction dust, construction noise, water quality, waste management, Landscape and Visual and Ecology.

Summary of Main Works Undertaken & Key Mitigation Measures Implemented

A5. Key activities carried out in this reporting period for the Contract included the followings:

Administration Building

- Installation of ceiling

- Painting works

- Installation of sanitary fitting

- Installation of vinyl flooring

- Installation of Aluminium Fins

- Installation of Internal partition wall and ceiling

- External wall finishing works

- Installation of AP doors and cat ladders

- Installation of wood decking

- Minor Installation of building services, cable laying and termination, Photovoltaic Panel Installation, Testing & Commissioning

Chemical building

- External wall painting works

- Defect rectification

Main Electrical & Central Chiller Plant Building

- Minor Installation of building services, electrical switchboard, cable laying, pressure test

- Ladder and Cover installation at Roof

ActiDAFF

- Sealing gap and wall openings

- Installation of signage

- Minor Installation of mechanical equipment, building services, minor cable laying and termination, Installation of Fibre Reinforced Polymer Cover, Testing & Commissioning

Product Water Storage Tank Building

- Installation of signage

- Installation of cladding works

- Tiling work at Roof Slab on Tank A

- Ladder and Cover installation at Roof

- Roof Tiles installation

- Minor Installation of building services, cable laying and termination, Testing & Commissioning

OSCG Building

- Core Opening at Cladding

- Installation of cladding works

- Installation of Railing on Brine Maker Tank

- Installation of building services, mechanical equipment and cable laying and termination, testing and commissioning and pressure test

Reverse Osmosis Building

- Installation of AP doors

- Installation of sanitary fitting

- Sanitary Ware Installation in Toilet

- Tiling Work in Toilet

- Installation of Water Meter Cabinets

- Installation of building services, electrical switchboard of cable laying and termination, Minor Installation of mechanical equipment and raised floor, testing and commissioning, Photovoltaic Panel Installation

Post Treatment Building

- DFMA Gap Seal Up

- Minor Installation of building services, Minor Installation of mechanical equipment, Cable laying and termination, Pressure Test

Inspection corridor

- Interior painting works

- Interior fitting out works

Combined Shaft and Pump room

- Installation of outfall grating and defect rectification .

- Minor cable laying and termination, testing and commissioning Guard House

- Guard house A defect rectification

- Guard house B defect rectification

- Minor Cable laying and Termination

Slope Work (Suspended due to landslides occurred during the rainstorm since 4 May 2024)

- Rock Dowel Installation

- Buttress Construction

- Wire Mesh Laying

- Drilling; Rock anchors installation, Rock break, Concreting Other

- Watermain installation works at CLP 132 Kv Substation

- Underground utility rectification work for Manhole and Draw pit

- Underground utility Construction Work for Watermain water

- Underground utility repair Work for Sewerage, Watermains work

- Security Fence footing construction work

- Light Pole installation work

- Road Construction

- Footpath Construction

- Landscape Construction

- Irrigation System installation

- Landscape planting work

- Traffic signage work

- Workshop construction work, Tiling work, green roof and irrigation pipe

- Workshop Building Services Installation, cable laying and termination

- Tiling work and cladding installation for Elevated Walkway

- Master meter defect rectification

- Wave deflector Wall

A6. The major environmental impacts brought by the above construction works include:

- Construction dust and noise generation from construction works, excavation works and slope works;

- Waste generation from the construction activities

A7. The key environmental mitigation measures implemented for the Contract in this reporting period associated with the above construction works include:

- Dust suppression by regular wetting and water spraying for construction works;

- Reduction of noise from equipment and machinery on-site and regular inspection to machinery and plants/vehicles on-site to ensure proper functioning;

Reporting Change

A17. There was no change to be reported that may affect the on-going EM&A programme.

Summary of Upcoming Key Issues and Key Mitigation Measures

A18. Key activities anticipated in the next reporting period for the Contract will include the followings:

Administration Building

- Installation of ceiling, door

- Painting works

- Tiling works

- Wall finishing works

- External wall finishing works

- Installation of AP doors and cat ladders

- Installation of Internal partition wall and ceiling

- Installation of wood decking

- Minor Installation of building services, cable laying and termination, Photovoltaic Panel Installation, Testing & Commissioning

Chemical building

- External wall painting works

- Defect rectification

Main Electrical & Central Chiller Plant Building

- Installation of signage

- Minor Installation of building services, electrical switchboard, cable laying, pressure test

ActiDAFF

- Sealing gap and wall openings

- Installation of signage

- Minor Installation of mechanical equipment, building services, minor cable laying

and termination, Installation of Fibre Reinforced Polymer Cover, Testing & Commissioning

Product Water Storage Tank Building

- Installation of signage

- Opening Seal Up

- Tiling work at Roof Slab on Tank A

- Minor Installation of building services, cable laying and termination, Testing & Commissioning

OSCG Building

- Installation of Railing on Brine Maker Tank

- Core Opening at DFMA

- Minor Installation of building services and pipework, cable laying and termination, and commissioning and pressure test

Reverse Osmosis Building

- Sanitary Ware Installation in Toilet

- Opening Seal Up

- Installation of Water Meter Cabinets

- Installation of signage

- Minor Installation of building services, cable laying and termination , testing and commissioning, Photovoltaic Panel Installation

Post Treatment Building

- Installation of signage

- DFMA Gap Seal Up

- Installation of Railing near Staircase

- Minor Installation of building services, Minor Installation of pipework, Cable laying and termination

Inspection corridor

- Interior painting works

- Interior fitting out works

Combined Shaft and Pump room

- Installation of outfall grating and defect rectification .

- Testing and commissioning Guard House

- Guard house A defect rectification

- Guard house B defect rectification

- Building Services Installation, cable laying and termination Other

- Watermain installation works at CLP 132 Kv Substation

- Underground utility rectification work for Manhole and Draw pit

- Underground utility Construction Work for Watermain water

- Underground utility repair Work for Sewerage, Watermains work

- Underground utility repair work (sampling pipe)

- Security Fence footing construction work

- Light Pole installation work

- Road Construction

- Footpath Construction

- Landscape Construction

- Irrigation System installation

- Landscape planting work

- Workshop construction work, Tiling work, green roof and irrigation pipe

- Workshop Building Services Installation, cable laying and termination

- Tiling work, glass balustrade and cladding installation for Elevated Walkway

- Master meter defect rectification

- Wave deflector Wall

A19. The major environmental impacts brought by the above construction works will include:

- Construction dust and noise generation from excavation, construction works and slope works; and

- Waste generation from construction activities.

A20. The key environmental mitigation measures for the Contract in the coming reporting period associated with the above construction works will include:

- Reduction of noise from equipment and machinery on-site;

- Dust suppression by regular wetting and water spraying for construction works and at main haul road;

- Sorting and storage of general refuse and construction waste;

- Deployment of silt curtain at the inshore water outflow; and

- Deployment protective fencing for trees.

Table 1.1 Contact Details of Key Personnel

Party

Position

Name

Telephone no.

Contract Proponent (Water Supplies Department)

SE/CM2

Milton Law

2634-3573

Supervising Officer (Binnies Hong Kong Limited)

Project Manager

Christina Ko

2608-7302

Chief Resident Engineer

Roger Wu

6343-1002

The Jardine Engineering Corporation, Limited, China State Construction Engineering (Hong Kong) Limited and Acciona Agua,

S.A. Trading

Project Manager

Stephen Yeung

2807-4665

Environmental Monitoring Manager

Brian Kam

9456-9541

Environmental Monitoring Manager

Tommy Law

6468-1782

Acuity Sustainability Consulting Limited

Environmental Team Leader

Toby Wan

9719-5422

Lam Environmental Services Limited

Independent Environmental Checker (IEC)

Serena Shek

6149-6683

Summary of Construction Works

1.7. Details of the major construction activities undertaken in this reporting period are shown below. The master programme is presented in Appendix A.

1.8. Key activities carried out in this reporting period for the Contract included the followings:

Administration Building

- Installation of ceiling

- Painting works

- Installation of sanitary fitting

- Installation of vinyl flooring

- Installation of Aluminium Fins

- Installation of Internal partition wall and ceiling

- External wall finishing works

- Installation of AP doors and cat ladders

- Installation of wood decking

- Minor Installation of building services, cable laying and termination, Photovoltaic Panel Installation, Testing & Commissioning

Chemical building

- External wall painting works

- Defect rectification

Main Electrical & Central Chiller Plant Building

- Minor Installation of building services, electrical switchboard, cable laying, pressure test

- Ladder and Cover installation at Roof

ActiDAFF

- Sealing gap and wall openings

- Installation of signage

- Minor Installation of mechanical equipment, building services, minor cable laying and termination, Installation of Fibre Reinforced Polymer Cover, Testing &

Commissioning

Product Water Storage Tank Building

- Installation of signage

- Installation of cladding works

- Tiling work at Roof Slab on Tank A

- Ladder and Cover installation at Roof

- Roof Tiles installation

- Minor Installation of building services, cable laying and termination, Testing & Commissioning

OSCG Building

- Core Opening at Cladding

- Installation of cladding works

- Installation of Railing on Brine Maker Tank

- Installation of building services, mechanical equipment and cable laying and termination, testing and commissioning and pressure test

Reverse Osmosis Building

- Installation of AP doors

- Installation of sanitary fitting

- Sanitary Ware Installation in Toilet

- Tiling Work in Toilet

- Installation of Water Meter Cabinets

- Installation of building services, electrical switchboard of cable laying and termination, Minor Installation of mechanical equipment and raised floor, testing

and commissioning, Photovoltaic Panel Installation

Post Treatment Building

- DFMA Gap Seal Up

- Minor Installation of building services, Minor Installation of mechanical equipment, Cable laying and termination, Pressure Test

Inspection corridor

- Interior painting works

- Interior fitting out works

Combined Shaft and Pump room

- Installation of outfall grating and defect rectification .

- Minor cable laying and termination, testing and commissioning Guard House

- Guard house A defect rectification

- Guard house B defect rectification

- Minor Cable laying and Termination

Slope Work (Suspended due to landslides occurred during the rainstorm since 4 May 2024)

- Rock Dowel Installation

- Buttress Construction

- Wire Mesh Laying

- Drilling; Rock anchors installation, Rock break, Concreting Other

- Watermain installation works at CLP 132 Kv Substation

- Underground utility rectification work for Manhole and Draw pit

- Underground utility Construction Work for Watermain water

- Underground utility repair Work for Sewerage, Watermains work

- Security Fence footing construction work

- Light Pole installation work

- Road Construction

- Footpath Construction

- Landscape Construction

- Irrigation System installation

- Landscape planting work

- Traffic signage work

- Workshop construction work, Tiling work, green roof and irrigation pipe

- Workshop Building Services Installation, cable laying and termination

- Tiling work and cladding installation for Elevated Walkway

- Master meter defect rectification

- Wave deflector Wall

1.9. A summary of the valid permits, licences, and/or notifications on environmental protection for this Contract is presented in Table 1.2.

Table 1.2 Summary of the Status of Valid Environmental Licence, Notification, Permit and Documentations

Permit/ Licences	Valid Period		Status	Remark
	From	To
Environmental Permit
EP-503/2015/B	Throughout the Contract		Valid
FEP - 01/503/2015/B	Throughout the Contract		Valid
Notification of Construction Works under the Air Pollution Control (Construction Dust) Regulation (Form NA)
451539	Throughout the Contract		Valid	-
Billing Account for Disposal of Construction Waste
7036276	Throughout the Contract		Valid	-
Sludge (Special Waste) Disposal (Admission Ticket)
17674	04/01/2024	30/06/2024	Valid	- The renewal application of “Sludge (Special Waste) Disposal (Admission Ticket)” was submitted.
Chemical Waste Producer Registration
5213-839-A2987-01	Throughout the Contract		Valid	-
Wastewater Discharge Licence (Land and Marine works)
WT00035775-2020	23/08/2021	31/07/2025	Valid	-
WT00044188-2023	16/06/2023	30/06/2028	Valid	- For Plant T&C and operation. - Variation of sampling point for the Discharge Licence Part 1 is in process.
Construction Noise Permit
GW-RE1514-23	22/12/2023	21/06/2024	Valid	-Renewal of CNP is in process.

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

Table 1.3 Summary of Status for Key Environmental Aspects under the EM&A Manual

Parameters	Status
Water Quality
Baseline Monitoring under EM&A Manual	The baseline water quality monitoring was conducted between 12 May 2020 to 6 June 2020.
Construction Phase Impact Monitoring	Ceased from 1 September 2023
Pre-operation phase Marine Impact Monitoring	On-going
Impact Monitoring of Effluent Discharge from Main Disinfection	Completed
Noise
Baseline Monitoring	The baseline noise monitoring result has been reported in Baseline Monitoring Report and submitted to EPD under EP Condition 3.4
Impact Monitoring	Completed
Waste Management
Mitigation Measures in Waste Management Plan	On-going
Landfill Gas
Regular Monitoring when construction works are within the 250 m Consultation Zone	On-going
Ecology (Coral)
Pre-operation phase Regular Coral Monitoring (Monthly)	On-going
Ecology (Fishery)
Pre-operation phase Regular Fishery Monitoring (Seasonally)	On-going
Ecology (Landscape)
Pre-operation phase Landscape and Visual Site Inspection	On-going
Environmental Audit
Site Inspection covering Measures of Air Quality, Noise Impact, Water Quality, Waste, Ecological Quality, Fisheries, Landscape and Visual	On-going

1.11. Other than the EM&A work by ET, environmental briefings, trainings, and regular environmental management meetings were conducted, in order to enhance environmental awareness and closely monitor the environmental performance of the contractors.

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

2. Noise

Monitoring Requirements

2.1. To ensure no adverse noise impact, noise monitoring is recommended to be carried out within 300m radius from the nearby noise sensitive receivers (NSRs), during construction phase. The NSRs selected as monitoring station are (i) NSR4 - Creative Secondary School,

(ii) NSR24 - PLK Laws Foundation College, and (iii) NSR31 - School of Continuing and Professional Studies - CUHK respectively.

2.2. Construction noise level were measured in terms of the A-weighted equivalent continuous sound pressure level (LAeq). Leq 30min was used as the monitoring parameter for the time period between 0700 and 1900 on normal weekdays. Construction works would follow stipulations of the valid Construction Noise Permits if works had to be conducted during restricted hours or public holidays. Table 2.1 summarizes the monitoring parameters, frequency, and duration of the impact noise monitoring.

Table 2.1 Noise Monitoring Parameters, Time, Frequency and Duration

Time

Duration

Interval

Parameters

Daytime: 0700-1900

Day time: 0700-1900

(during normal weekdays)

Continuously in

Leq 5min/Leq 30min (average of 6 consecutive Leq 5min)

Leq 30min

L10 30min & L90 30min

Monitoring Locations

2.3. The monitoring locations were normally made at a point 1m from the exterior of the NSRs building façade and be at a position 1.2m above the ground. A correction of +3dB(A) should be made to the free-field measurements.

2.4. According to the environmental findings detailed in the EIA report and Baseline Monitoring Report, the designated locations for the construction noise monitoring are listed in Table 2.2 below.

Table 2.2 Noise Sensitive Receivers

NSR ID	Noise Sensitive Receivers	Monitoring Location	Position
NSR 4	Creative Secondary School	Roof Floor	1 m from facade
NSR 24	PLK Laws Foundation College	Pedestrian Road on Ground Floor	Free-field
NSR 31	School of Continuing and Professional Studies - CUHK	Roof Floor	1 m from facade

2.5. Three noise monitoring locations for impact monitoring at the nearby sensitive receivers are shown in Figure 2.1-2.3.

Figure 2.1 NSR4 Creative Secondary School

Figure 2.2 NSR24 PLK Laws Foundation College

Figure 2.3 NSR31 School of Continuing and Professional Studies - CUHK

Impact Monitoring Methodology

2.6. Integrated sound level meter will be used for the noise monitoring. The meter will be in compliance with the International Electrotechnical Commission Publications 651: 1979 (Type 1) and 804: 1985 (Type 1) specifications. Immediately prior to and following each noise measurement the accuracy of the sound level meter will be checked using an acoustic calibrator generating a known sound pressure level at a known frequency. Measurements will be accepted as valid only if the calibration levels before and after the noise measurements agree to within 1.0 dB(A).

2.7. Noise measurements were not made in the presence of fog, rain, wind with a steady speed exceeding 5 m/s or wind with gusts exceeding 10 m/s. The wind speed shall be checked with a portable wind speed meter capable of measuring the wind speed in m/s.

Action and Limit Levels

2.8. The Action/Limit Levels are in line with the criteria of Practice Note for Professional Persons (ProPECC PN 2/93) “Noise from Construction Activities - Non-statutory Controls” and Technical Memorandum on Environmental Impact Assessment Process issued by HKSAR Environmental Protection Department [“EPD”] under the Environmental Impact Assessment Ordinance, Cap 499, S.16 are presented in Table 2.3.

Table 2.3 Action and Limit Levels for Noise per EM&A Manual

Time Period

Action

Limit (dB(A))

0700-1900 on normal weekdays

When one documented complaint is received from any one of the noise sensitive receivers

- 70 dB(A) for school and

- 65 dB(A) during examination period

Note: Limits specified in the GW-TM and IND-TM for construction and operation noise, respectively.

2.9. If exceedances were found during noise monitoring, the actions in accordance with the Event and Action Plan shall be carried out according to Appendix E.

Monitoring Results and Observations

2.10. Referring to EM&A Manual Section 4.1.2, the impact noise monitoring should be carried out when there are Contract-related construction activities undertaken within a radius of 300m from the monitoring stations. As no Contract-related construction activities were undertaken in the reporting month within a radius of 300m from the monitoring stations as shown in Figure 2.4, no impact noise monitoring was conducted in the reporting period.

Figure 2.4 Site Layout Plan with Noise Sensitive Receivers and Desalination Plant

3. Water Quality

3.1. In accordance with the recommendations of the EIA, water quality monitoring is required during dredging for the submarine pipelines and, during operation phase. The following Section provides details of the water quality monitoring to be undertaken by the Environmental Team (ET) to verify the distance of sediment and brine plume dispersion and to identify whether the potential exists for any indirect impacts to occur to ecological sensitive receivers.

3.2. The water quality monitoring programme was be carried out to allow any deteriorating water quality to be readily detected and timely action taken to rectify the situation.

3.3. Water quality monitoring for the Contract can be divided into the following stages:

- Dredging activities during construction phase;

- Discharge of effluent from main disinfection during construction phase; and

- Operation activities during Pre-operation phase.

Water Quality Parameters

3.4. The parameters that have been selected for measurement in situ and in the laboratory are those that were either determined in the EIA to be those with the most potential to be affected by the construction works or are a standard check on water quality conditions. Parameters to be measured in the impact monitoring are listed in Table 3.1.

Table 3.1 Parameters measured in the Impact Marine Water Quality Monitoring

Parameters	Unit	Abbreviation
In-situ measurements
Dissolved oxygen	mg/L	DO
Temperature	oC	-
pH	-	-
Turbidity	NTU	-
Salinity	0/00	-
Total Residual Chlorine NOTE1	mg/L	TRC
Laboratory measurements
Suspended Solids	mg/L	SS
Iron-Soluble	mg/L	Fe
Anti-scalant as Reactive Phosphorus	mg/L	PO4 as P-

NOTE 1: Monitoring of Total Residual Chlorine will be conducted when cleaning and sterilization of the new freshwater main is carried out.

3.5. In addition to the water quality parameters, other relevant data were also being measured and recorded in Water Quality Monitoring Logs, including the location of the sampling stations, water depth, time, weather conditions, sea conditions, tidal stage, current direction and velocity, special phenomena and work activities undertaken around the monitoring and works area that may influence the monitoring results.

Monitoring Equipment

3.6. For water quality monitoring, the following equipment were used:

3.8. On-site calibration of field equipment was following the “Guide to On-Site Test Methods for the Analysis of Waters”, BS 1427: 2009. Sufficient stocks of spare parts were maintained for replacements when necessary. Backup monitoring equipment was made available so that monitoring can proceed uninterrupted even when equipment is under maintenance, calibration etc.

Laboratory Measurement and Analysis

3.9. Sufficient volume of each water sample was collected for carrying out the laboratory analyses. Using chain of custody forms, collected water samples were transferred to a HOKLAS accredited laboratory (Acumen Laboratory and Testing Limit - HOKLAS 241) for immediate processing. The determination work was start within the next working day after collection of the water samples. Analytical methodology and sample preservation of other parameters were based on the latest edition of Standard Methods for the Examination of Waste and Wastewater published by APHA, AWWA and WPCF and methods by USEPA, or suitable method in accordance with requirements of HOKLAS or another internationally accredited scheme. The QA/QC details were in accordance with the requirements of HOKLAS or another internationally accredited scheme.

3.10. Parameters for laboratory measurements, standard methods and detection limits are presented in Table 3.2.

Table 3.2 Laboratory measurements, standard methods, and corresponding detection limits of marine water quality monitoring

Parameters	Standard Methods	Detection Limit	Reporting Limit	Precision
Dissolved oxygen	Instrumental, CTD	0.1	-	+-25%
Temperature	Instrumental, CTD	0.1	-	+-25%
pH	Instrumental, CTD	0.1	-	+-25%
Turbidity	Instrumental, CTD	0.1	-	+-25%
Salinity	Instrumental, CTD	0.1	-	+-25%
Suspended Solids	APHA 23rd Ed 2540D	1.0	2.5	+-17%
Iron	APHA 3111 B	0.2	-	+-25%
Total residual chlorine	Test Kit (Lovibond MD200)	Lowest limit = 0.01mg/L; Upper limit = 6 mg/L	-	+-25%

Monitoring Location

Construction Phase

3.11. The Impact water quality monitoring was ceased from 1 September 2023 due to the completion of marine-related construction works.

Pre-operation phase

3.12. The pre-operation phase impact water quality monitoring locations are in accordance with the EM&A Manual and detailed in Table 3.3 below. A schedule for water quality monitoring was prepared by the ET and submitted to IEC and EPD prior to the commencement of the monitoring.

Table 3.3 Location of Impact Water Quality Monitoring Stations

Station	Easting	Northing	Description
CE	843550	815243	Upstream control station at ebb tide
CF	846843	810193	Upstream control station at flood tide
WSR1	846864	812014	Ecological sensitive receiver at Tung Lung Chau
WSR2	847645	812993	Fisheries sensitive receiver at Tung Lung Chau
WSR3	848023	813262	Ecological sensitive receiver at Tung Lung Chau
WSR4	847886	814154	Ecological sensitive receiver at Tai Miu Wan
WSR16	845039	815287	Ecological sensitive receiver at Fat Tong Chau
WSR33	847159	814488	Ecological sensitive receiver at Tai Miu Wan
WSR36	846878	814081	Ecological sensitive receiver at Kwun Tsai
WSR37	846655	813810	Ecological sensitive receiver at Tit Cham Chau
NF1	846542	813614	Edge of Mixing zone, ~ 200m west of outfall diffuser
NF2	846942	813614	Edge of Mixing zone, ~ 200m east of outfall diffuser
NF3	846742	813414	Edge of Mixing zone, ~ 200m south of outfall diffuser

3.13. WSR1 to WSR37 were identified in accordance with Annex 14 of the EIAO-TM as well as Clause 3.4.4.2 of the Environmental Impact Assessment Study Brief for Desalination Plant at Tseung Kwan O (No. ESB-266/2013). WSR1 to WSR3 are sited near the Tung Lung Chau Fish Culture Zone; WSR16 and WSR36 are sited near the coral assemblages along the coastlines of Fat Tong Chau and Kwun Tsai respectively; WSR 4 and WSR33 are sited near the Coastal Protection Area and coral assemblages in waters of Tai Miu Wan; WSR37 is sited near the fisheries resource including spawning and nursery grounds at the coastal water of Tit Cham Chau. NF1 to NF3 are the Edge of Mixing zone.

Figure 3.1 Impact water quality monitoring locations under EM&A Manual

Sampling Frequency

Pre-operation phase

3.14. Impact water quality monitoring were carried out three days per week during the commission phase. Monitoring at each station was undertaken once per day. The interval between two sets of monitoring was not less than 36 hours. The monitoring frequency would be increased in the case of exceedances of Action/Limit Levels if considered necessary by ET. Monitoring frequency would be maintained as far as practicable.

Sampling Depths & Replication

3.15. During impact water quality monitoring, each station was sampled, and measurements/ water samples were taken at three depths, 1 m below the sea surface, mid-depth, and 1 m above the seabed. For in situ measurements, duplicate readings were made at each water depth at each station. Duplicate water samples were collected at each water depth at each station.

Action and Limit Levels

Pre-operation phase

3.16. The Action and Limit Levels have been set based on the derivation criteria specified in the EM&A Manual. The Action/Limit Levels have been derived and are presented in Table 3.4.

Rev.	Description of Modification	Date
1.	First Issue for Comments	05/06/2024
2.	Revised According to Comments	12/06/2024
3.	Revised According to Comments	12/06/2024

Parameters	Action	Limit
Pre-operation phase Impact Monitoring
DO in mg/L	Surface and Middle 7.30 mg L-1 Bottom 7.31 mg L-1 Tung Lung Chau Fish Culture Zone 5.1 mgL-1 or level at control station (Whichever the lower)	Surface and Middle 4 mg L-1 Bottom 2 mg L-1 Tung Lung Chau Fish Culture Zone 5.0 mgL-1 or level at control station (Whichever the lower)
SS in mg/L (Depth- averaged)	5.00 mg L-1 or 20% exceedance of value at any impact station compared with corresponding data from control station	6.00 mg L-1 or 30% exceedance of value at any impact station compared with corresponding data from control station
Turbidity in NTU (Depth- averaged)