EXECUTIVE SUMMARY

INTRODUCTION

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/A) 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 27th 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 2022 to 31 May 2022.

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:

- Land Survey;

- Construction of manholes no.15 and no.16 adjacent to ActiDAFF and RO;

- Construction of manholes no.2, no.3 and no.4 adjacent to ActiDAFF;

- Construction of 132kV adjacent to underground utilities

- Construction of manholes no.6 and no.7 Glass Reinforced Plastic (GRP) pipe installation;

- Construction of underground utility adjacent to 132kV Substation;

- Construction of solar panel supports at roof of ActiDAFF;

- Construction of Reverse Osmosis (RO) Building - staircases and internal finishing;

- Construction of sludge thickener, Post Treatment Building (PTB);

- Construction of On-Site Chlorine Generation Building (OSCG Bldg) and CO2 Tank area;

- Internal finishing work at Product Water Storage Tank (PWST), Main Electrical & Central Chiller Plant Building;

- Manhole construction and GRP pipe installation;

- Construction of 1/F to 2/F walls and columns of Administration Building;

- Construction of footings F5 and F6 of inspection corridor;

- Construction of parapet of Chemical Building;

- Construction of common wall of Combined Shaft;

- Outfall Shaft - Dewatering;

- Intake shaft - Retrieval of DN 2500 TBM under water;

- Intake tunnel - Demobilize the pipe jacking system and grouting works commence;

- Construction of combined shaft and pump room;

- Slope works - Scaffolding erection for rock mapping and tree survey;

- Open Channel - Trench Excavation and structure installation;

- E&M works - ActiDAFF - scaffolding, installation of E&M piping;

- E&M works - Reverse Osmosis (RO) Building - Fire services installation;

- E&M works - CO2 Tank area - installation of silos; and

- E&M works - Chiller Building - Installation of chillers

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

- Construction dust and noise generation from marine construction works, excavation works, construction works, rock cutting works and pipe piling driving works

- Waste generation from the construction activities

- Impact on water quality from marine construction works and inland construction works

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;

- Sorting and storage of general refuse and construction waste; and

- Deployment of temporary silt curtain in the area where marine construction works were conducted and deployment of water sedimentation tanks for treatment of wastewater at inland and marine areas before discharge.

SUMMARY OF EXCEEDANCE & INVESTIGATION & FOLLOW-UP

A8. No noise monitoring was conducted during the reporting period since there are no Contract -related construction activities undertaken within a radius of 300m from the monitoring locations. No exceedance of the Action Level was recorded during the reporting period.

A9. The EM&A works for water quality were conducted during the reporting period in accordance with the EM&A Manual.

A10. Nineteen (19) of the general water quality monitoring results of suspended solids (SS) obtained had exceeded the Action Level. Six (6) of the general water quality monitoring results of SS obtained during the reporting period had exceeded the Limit Level.

A11. Details of the exceedance are presented in Appendix O.

A12. Investigation on the reason of exceedance has been carried out, where the exceedances of SS on 3, 5, 7, 12, 14, 21, 26, 28 and 31 May 2022 were concluded to be unrelated to the Contract as detailed in the Incident Reports on Action Level or Limit Level Non- compliance along with supporting materials in Appendix O.

A13. It was concluded that all exceedances recorded in the reporting month were unrelated to the Contract.

A14. In this reporting period, 44 times of landfill gas monitoring was conducted at Wan Po Road (Ch1+360 - Ch1+513).

A15. No exceedance of action and limit levels of methane, oxygen and carbon dioxide was recorded in the reporting month.

A16. Joint site inspections of the construction work by ET and IEC were carried out on 3, 10, 17, 24 and 31 May 2022 to audit the mitigation measures implementation status. Observations and recommendations were recorded in the site inspection checklists and provided to the contractors together with the appropriate follow-up actions where necessary.

COMPLAINT HANDLING AND PROSECUTION

A17. No environmental complaint was received during the reporting period.

A18. Neither notification of summons nor prosecution was received for the Contract.

REPORTING CHANGE

A19. 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

A20. Key activities anticipated in the next reporting period for the Contract will include the followings:

- Construction of 132kV adjacent to underground utilities;

- Construction of Reverse Osmosis (RO) Building - staircases and internal finishing;

- Construction of sludge thickener, Post Treatment Building (PTB);

- Construction of On-Site Chlorine Generation Building (OSCG Bldg) and CO2 Tank area;

- Internal finishing work at Product Water Storage Tank (PWST), Main Electrical & Central Chiller Plant Building;

- Manhole construction and Glass Reinforced Plastic (GRP) pipe installation;

- Construction of 2/F and 3/F walls and columns of Administration Building;

- Installation of curtain wall supports of Administration Building;

- Construction of footings and columns of FT‐5, FT‐6, FT‐7 and FT‐8 of inspection corridor;

- Construction of Stair Tower of inspection corridor;

- Construction of side tanks no.2, 3 and 4 of ActiDAFF;

- Construction of manholes no.15 and no.16 adjacent to ActiDAFF and RO;

- Construction of manhole no.2, no.3 and no.4 adjacent to ActiDAFF;

- Construction of manholes no.6 and no.7 Glass Reinforced Plastic (GRP) pipe installation;

- Outfall Shaft - Dewatering;

- Intake shaft - retrieval of DN2500 TBM under water;

- Intake shaft - General cleaning for finial inspection;

- Outfall Tunnel - Demobilize the pipe jacking system and grouting;

- Construction of combined shaft and pump room;

- Slope works - Scaffolding erection for rock mapping and tree survey;

- Open Channel - Trench Excavation and structure installation;

- E&M works - ActiDAFF - scaffolding, installation of E&M piping;

- E&M works - RO- installation of fire services, steel pipe, GRP pipe;

- E&M works - CO2 tank area - installation of vaporizers;

- E&M works - Chiller Building - installation of chillers, electrical system;

- E&M works - Product water Building - installation of pluming, air duct and electoral system.

A21. The major environmental impacts brought by the above construction works will include:

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

- Waste generation from construction activities; and

- Impact on water quality from marine construction works and inland construction works.

A22. 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;

- Sorting and storage of general refuse and construction waste; and

Table 1.1 Contact Details of Key Personnel

Party

Position

Name

Telephone no.

Contract Proponent (Water Supplies Department)

SE/CM2

Benny Lam

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

Acuity Sustainability Consulting Limited

Environmental Team Leader

Jacky Leung

2698-6833

ANewR Consulting Limited

Independent Environmental Checker (IEC)

Louis Kwan

2618-2831

SUMMARY OF CONSTRUCTION WORKS

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

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

- Land Survey;

- Construction of manholes no.15 and no.16 adjacent to ActiDAFF and RO;

- Construction of manholes no.2, no.3 and no.4 adjacent to ActiDAFF;

- Construction of 132kV adjacent to underground utilities

- Construction of manholes no.6 and no.7 Glass Reinforced Plastic (GRP) pipe installation;

- Construction of underground utility adjacent to 132kV Substation;

- Construction of solar panel supports at roof of ActiDAFF;

- Construction of Reverse Osmosis (RO) Building - staircases and internal finishing;

- Construction of sludge thickener, Post Treatment Building (PTB);

- Construction of On-Site Chlorine Generation Building (OSCG Bldg) and CO2 Tank area;

- Internal finishing work at Product Water Storage Tank (PWST), Main Electrical & Central Chiller Plant Building;

- Manhole construction and GRP pipe installation;

- Construction of 1/F to 2/F walls and columns of Administration Building;

- Construction of footings F5 and F6 of inspection corridor;

- Construction of parapet of Chemical Building;

- Construction of common wall of Combined Shaft;

- Outfall Shaft - Dewatering;

- Intake shaft - Retrieval of DN 2500 TBM under water;

- Intake tunnel - Demobilize the pipe jacking system and grouting works commence;

- Construction of combined shaft and pump room;

- Slope works - Scaffolding erection for rock mapping and tree survey;

- Open Channel - Trench Excavation and structure installation;

- E&M works - ActiDAFF - scaffolding, installation of E&M piping;

- E&M works - Reverse Osmosis (RO) Building - Fire services installation;

- E&M works - CO2 Tank area - installation of silos; and

- E&M works - Chiller Building - Installation of chillers

1.10. 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/ Licenses/ Notification	Reference	Validity Period
Environmental Permit	FEP - 01/503/2015/A	Throughout the Contract
Notification of Construction Works under the Air Pollution Control (Construction Dust) Regulation (Form NA)	Ref. No.: 451539	Throughout the Contract
Billing Account for Disposal of Construction Waste	7036276	Throughout the Contract
Chemical Waste Producer Registration	5213-839-A2987-01	Throughout the Contract
Wastewater Discharge Licence (Land and Marine works)	WT00035775-2020	23/08/2021 - 31/07/2025
Construction Noise Permit for general works, TBM at combined shaft and marine works	GW-RE0337-22	01/05/2022 - 31/10/2022

1.11. 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 Jun 2020
Impact Monitoring	On-going
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	On-going
Waste Management
Mitigation Measures in Waste Management Plan	On-going
Landfill Gas
Regular Monitoring when Construction Works are within the 250m Consultation Zone	In this reporting period, 44 times of landfill gas monitoring was conducted at Wan Po Road (Ch1+360 - Ch1+513).
Environmental Audit
Site Inspection covering Measures of Air Quality, Noise Impact, Water Quality, Waste, Ecological Quality, Fisheries, Landscape and Visual	On-going

1.12. 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.

1.13. 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 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. In accordance with the EM&A Manual, baseline noise level at the noise monitoring stations were established as presented in the Baseline Monitoring Report. Impact noise monitoring will be conducted once per week in the form of 30-minutes measurements Leq, L10 and L90 levels recorded at each monitoring station between 0700 and 1900 on normal weekdays.

2.3. Referring to EM&A manual Section 4.1.2, the impact noise monitoring should be carried out at all the designated monitoring stations when there are contract-related construction activities undertaken within a radius of 300m from the monitoring stations.

2.4. No impact monitoring for noise impact was conducted in the reporting month due to the overly distant monitoring station from the works location, where they were farther than 1 km from the closest monitoring station NSR4 to the works location.

2.5. Impact noise monitoring will be conducted weekly in the reporting period between 0700- 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.

2.6. 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. 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

IMPACT MONITORING METHODOLOGY

2.10. Integrated sound level meter was used for the noise monitoring. The meter was 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 was checked using an acoustic calibrator generating a known sound pressure level at a known frequency. Measurements was accepted as valid only if the calibration levels before and after the noise measurements agree to within 1.0 dB(A). Calibration certificates of the instruments used to be shown at Appendix F are intentionally left blank since no impact monitoring equipment was used in the reporting month.

2.11. 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

2.12. 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.

2.13. 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

2.14. 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. No monitoring station was located within a radius of 300m of the Contract site as shown in Figure 2.4, no impact monitoring for noise impact 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. In addition, baseline water quality monitoring will be required prior to the commencement of marine construction activities. 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. The water quality monitoring programme will be carried out to allow any deteriorating water quality to be readily detected and timely action taken to rectify the situation. The status and locations of water quality sensitive receivers and the marine works location may change after issuing this Document. If required, the ET in consultation with IEC will propose updated monitoring locations and seek approval from EPD.

3.2. 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;

- Operation phase - first year upon commissioning; and,

- Continuous monitoring of effluent quality.

WATER QUALITY PARAMETERS

3.3. 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.

3.4. 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

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

Dissolved Oxygen and Temperature Measuring Equipment - The instrument was a portable, weatherproof dissolved oxygen measuring instrument complete with cable, sensor, comprehensive operation manuals, and was operable from a DC power source. It was capable of measuring: dissolved oxygen levels in the range of 0 - 20 mg/L and 0 - 200% saturation; and a temperature of 0 - 45 degrees Celsius. It has a membrane electrode with automatic temperature compensation complete with a cable of not less than 35 m in length. Sufficient stocks of spare electrodes and cables were available for replacement where necessary (e.g. YSI model 59 DO meter, YSI 5739 probe, YSI 5795A submersible stirrer with reel and cable or an approved similar instrument).

Turbidity Measurement Equipment - The instrument was a portable, weatherproof turbidity-measuring unit complete with cable, sensor and comprehensive operation manuals. The equipment was operated from a DC power source, it has a photoelectric sensor capable of measuring turbidity between 0 - 1000 NTU and complete with a cable with at least 35 m in length (for example Hach 2100P or an approved similar instrument).

Salinity Measurement Instrument - A portable salinometer capable of measuring salinity in the range of 0 - 40 ppt was provided for measuring salinity of the water at each monitoring location.

Water Depth Gauge - A portable, battery-operated echo sounder (for example Seafarer 700 or a similar approved instrument) was used for the determination of water depth at each designated monitoring station. This unit will preferably be affixed to the bottom of the work boat if the same vessel is to be used throughout the monitoring programme. The echo sounder was suitably calibrated.

Positioning Device - A Global Positioning System (GPS) was used during monitoring to allow accurate recording of the position of the monitoring vessel before taking measurements. The Differential GPS, or equivalent instrument, was suitably calibrated at appropriate checkpoint (e.g. Quarry Bay Survey Nail) to verify that the monitoring station is at the correct position before the water quality monitoring commence.

Water Sampling Equipment - A water sampler, consisting of a PVC or glass cylinder of not less than two litres, which can be effectively sealed with cups at both ends, was used (e.g. Kahlsico Water Sampler 13SWB203 or an approved similar instrument). The water sampler has a positive latching system to keep it open and prevent premature closure until released by a messenger when the sampler is at the selected water depth.

Total Residual Chlorine for Discharge of Sterilization Water - Total residual chlorine (TRC) shall be measured in-situ using a handheld colorimeter with its testing toolkits.

SAMPLING / TESTING PROTOCOLS

3.6. All in situ monitoring instruments were checked, calibrated and certified by a laboratory accredited under HOKLAS or any other international accreditation scheme before use, and subsequently re-calibrated at monthly intervals throughout the stages of the water quality monitoring. Responses of sensors and electrodes were checked with certified standard solutions before each use.

3.7. Table 3.2 summarizes the equipment used in the water quality monitoring program. The copies of the calibration certification of multi-parameter water quality system are shown in the Appendix N.

Table 3.2 Water Quality Monitoring Equipment

Equipment	Model & Make	Serial Number	Calibration Expiry Date	Qty.
Water Sampler	A 2-Litre transparent PVC cylinder with latex cups at both ends (Kahlsico Water Sampler 13SWB20)	-	-	1
Multi- parameter Water Quality System	HORIBA U-53	PPHNOMXY	10 Aug 22	2
Multi- parameter Water Quality System	YSI ProDSS	22C106561	19 Jul 22	2

3.8. On-site calibration of field equipment was follow 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. All laboratory works were carried out in a HOKLAS accredited laboratory. Sufficient volume of each water sample was collected at the monitoring stations for carrying out the laboratory analyses. Using chain of custody forms, collected water samples were transferred to a HOKLAS accredited laboratory for immediate processing. The determination work was start within the next working day after collection of the water samples. The laboratory measurements were provided to the client within 5 working days of the sampling event. 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 submitted information was including pre-treatment procedures, instrument use, Quality Assurance/Quality Control (QA/QC) details (such as blank, spike recovery, number of duplicate samples per-batch etc), detection limits and accuracy. The QA/QC details were in accordance with requirements of HOKLAS or another internationally accredited scheme.

3.10. Parameters for laboratory measurements, standard methods and detection limits are presented in Table 3.3.

Table 3.3 Laboratory measurements, standard methods and corresponding detection limits of marine water quality monitoring

Parameters	Standard Methods	Detection Limit	Reporting Limit	Precision
Dissolved oxygen (mg/L)	Instrumental, CTD	0.1	-	+-25%
Temperature (oC)	Instrumental, CTD	0.1	-	+-25%
pH	Instrumental, CTD	0.1	-	+-25%
Turbidity (NTU)	Instrumental, CTD	0.1	-	+-25%
Salinity (0/00)	Instrumental, CTD	0.1	-	+-25%
Suspended Solids (mg/L)	APHA 23rd Ed 2540D	1.0	2.5	+-17%
Total Residual Chlorine (mg/L)	APHA 21st Ed 4500 - ClG	0.1	0.2	+-10%
Iron-soluble	USEPA 6010C	0.2	0.2	+-25%
Anti-scalant as Reactive phosphorus	APHA 4500P: B&F	0.01	0.01	+-25%

3.11. If exceedances were found during water monitoring, the actions in accordance with the Event and Action Plan will be carried out according to Appendix G.

MONITORING LOCATION

3.12. The Impact water quality monitoring locations are in accordance with the EM&A Manual and detailed in Table 3.4 below. A schedule for water quality monitoring was prepared by the ET and approved by IEC and EPD prior to the commencement of the monitoring.

Table 3.4 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.

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

SAMPLING FREQUENCY

3.14. During periods when there are dredging works, impact monitoring was undertaken at the monitoring stations as shown in Figure 3.1 and Table 3.4 three days per week during the construction phase after the commencement of marine construction works and dredging activities. Monitoring at each station was undertaken at both mid-ebb and mid-flood tides on the same day. The tidal range selected for the impact monitoring was at least 0.5 m for both flood and ebb tides as far as practicable. 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.

3.15. The monitoring location/position, time, water depth, water temperature, salinity, weather conditions, sea conditions, tidal stage, special phenomena and work underway at the marine works site were recorded.

SAMPLING DEPTHS & REPLICATION

3.16. For Impact monitoring, each station was sampled and measurements/ water samples was taken at three depths, 1 m below the sea surface, mid-depth and 1 m above the seabed. For stations that are less than 3 m in depth, only the mid depth sample was taken. For stations that are less than 6 m in depth, only the surface and seabed sample were taken. 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. All water quality monitoring results were summarized in Appendix L.

ACTION AND LIMIT LEVELS

3.17. 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 3.5.

MONITORING PROGRAMME

3.18. The ET of the Contract had conducted the baseline water monitoring between 12 May 2020 to 6 Jun 2020 at the thirteen designated monitoring stations and the six designated monitoring at waters near TKO in accordance with the EM&A Manual and Contract Specification respectively. The baseline monitoring results was presented in Baseline Water Quality Monitoring Report separately.

3.19. The commencement of marine construction and dredging activities for the Contract have been conducted in March and April 2021 respectively.

Table 3.5 Derived Action and Limit Levels for Water Quality

Parameters	Action	Limit
Construction Phase Impact Monitoring
DO in mg/L	Surface and Middle	Surface and Middle
	7.30 mg L-1	4 mg L-1
	Bottom	Bottom
	7.31 mg L-1	2 mg L-1
	Tung Lung Chau Fish Culture Zone	Tung Lung Chau Fish Culture Zone
	5.1 mgL-1 or level at control station	5.0 mgL-1 or level at control station
	(whichever the lower)	(whichever the lower)
SS in mg/L	5.00 mg L-1 or 20% exceedance of	6.00 mg L-1 or 30% exceedance of
(Depth-averaged)	value at any impact station	value at any impact station
	compared with corresponding data	compared with corresponding data
	from control station	from control station
Turbidity in NTU	2.41 NTU or 20% exceedance of	2.84 NTU or 30% exceedance of
(Depth-averaged)	value at any impact station	value at any impact station
	compared with corresponding data	compared with corresponding data
	from control station	from control station
First-year Operation Phase Monitoring iv
DO in mg/L	Surface and Middle	Surface and Middle
	7.30 mg L-1	4 mg L-1
	Bottom	Bottom
	7.31 mg L-1	2 mg L-1
	Tung Lung Chau Fish Culture Zone	Tung Lung Chau Fish Culture Zone
	5.1 mgL-1 or level at control station	5.0 mgL-1 or level at control station
	(whichever the lower)	(whichever the lower)
SS in mg/L	5.00 mg L-1 or 20% exceedance of	6.00 mg L-1 or 30% exceedance of
(Depth-averaged)	valueat any impact station	value at any impact station
	compared with corresponding data	compared with corresponding data
	from control station	from control station
Turbidity in NTU (Depth-averaged)	2.41 NTU or 20% exceedance of value at any impact station compared with corresponding data from control station	2.84 NTU or 30% exceedance of value at any impact station compared with corresponding data from control station
Salinity in PSU (Depth-averaged)	34.28 PSU or 9% exceedance of value at any impact station compared with corresponding data from control station	34.60 PSU or 10% exceedance of value at any impact station compared with corresponding data from control station
Iron in mg/L (Depth-averaged)	0.3 mgL-1	0.3 mgL-1

Notes:

i. "Depth-averaged" is calculated by taking the arithmetic means of reading of all three depths.

ii. For DO, non-compliance of the water quality limits occurs when monitoring result is lower than the limits.

iii. For Turbidity, SS, iron and Salinity, non-compliance of the water quality limits occurs when monitoring result is higher than the limits.

iv. For the Action and Limit Levels adopted during First-year Operation Phase Monitoring, further review would be made according to the EM&A Manual during Operation Phase.

MONITORING RESULTS AND OBSERVATIONS

3.20. General water quality monitoring at the ten monitoring stations (CE, CF, WSR1, WSR2, WSR3, WSR4, WSR16, WSR33, WSR36 and WSR37) were conducted on 3, 5, 7, 10, 12, 14, 17, 19, 21, 24, 26, 28 and 31 May 2022.

3.21. Nineteen (19) of the general water quality monitoring results of suspended solids (SS) obtained had exceeded the Action Level. Six (6) of the general water quality monitoring results of SS obtained during the reporting period had exceeded the Limit Level. Details of the exceedance are presented in Appendix O.

3.22. Investigation on the reason of exceedance has been carried out, where the exceedances of SS on 3, 5, 7, 12, 14, 21, 26, 28 and 31 May 2022 were concluded to be unrelated to the Contract as detailed in the Incident Reports on Action Level or Limit Level Non- compliance along with supporting materials in Appendix O.

3.23. Monitoring results of 6 key parameters: Salinity, DO, turbidity, SS, pH and temperature in this reporting, are summarized in Table 3.6 and Table 3.7, and detailed results are presented in Appendix L.

Table 3.6 Summary of Impact Water Quality Monitoring Results (Mid-Flood)

Locations		Parameters
		Salinity (ppt)	Dissolved Oxygen (mg/L)		pH	Turbidity (NTU)	Suspended Solids (mg/L)	Temp.(oC)
		Salinity (ppt)	Surface & Middle	Bottom	pH	Turbidity (NTU)	Suspended Solids (mg/L)	Temp.(oC)
CE	Avg.	32.7	9.0	9.0	8.2	3.3	3.9	25.1
	Min.	31.1	8.1	8.1	7.9	2.6	2.5	21.5
	Max.	33.7	10.0	10.1	8.4	4.3	13.0	26.3
CF	Avg.	32.6	8.9	8.9	8.2	4.0	4.6	25.4
	Min.	31.2	8.0	8.0	8.1	3.4	2.5	23.8
	Max.	33.4	9.7	9.6	8.4	5.0	16.0	26.5
WSR1	Avg.	32.7	9.0	9.0	8.2	2.7	4.0	25.4
	Min.	30.4	8.0	8.1	7.9	1.8	2.5	23.9
	Max.	33.8	9.7	9.6	8.5	4.1	14.0	26.5
WSR2	Avg.	32.5	9.0	8.9	8.2	2.4	3.7	25.5
	Min.	30.3	8.1	8.2	8.0	1.8	2.5	24.3
	Max.	33.6	9.9	9.8	8.4	3.6	11.0	26.7
WSR3	Avg.	32.6	8.9	8.9	8.2	2.7	4.7	25.5
	Min.	30.7	8.1	8.1	8.0	1.8	2.5	24.4
	Max.	33.6	9.7	9.8	8.4	4.3	24.0	26.3
WSR4	Avg.	32.5	9.0	9.0	8.2	2.8	5.0	25.5
	Min.	30.8	8.3	8.3	8.1	1.9	2.5	24.2
	Max.	33.7	9.6	9.5	8.4	4.2	33.0	26.3
WSR16	Avg.	32.7	8.9	8.9	8.2	2.9	3.9	25.5
	Min.	31.1	8.0	8.0	8.1	2.1	2.5	24.3
	Max.	33.6	9.9	9.9	8.3	4.2	12.0	26.8
WSR33	Avg.	32.6	8.8	8.7	8.2	2.8	4.3	25.7
	Min.	30.7	8.1	8.2	8.0	2.0	2.5	24.4
	Max.	33.7	9.8	9.8	8.4	4.0	12.0	26.6
WSR36	Avg.	32.4	9.0	9.0	8.2	2.8	4.8	25.4
	Min.	31.1	8.4	8.4	8.0	1.8	2.5	24.2
	Max.	33.2	9.8	9.8	8.4	3.8	13.0	26.4
WSR37	Avg.	32.8	8.9	8.9

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