CONTENTS

Executive Summary.................................................................................................................................................................. 1

1.         Basic Contract Information.......................................................................................................................................... 6

2.         Noise.................................................................................................................................................................................... 11

3.         Water Quality................................................................................................................................................................... 15

4.         Waste................................................................................................................................................................................... 29

5.         Landfill Gas Monitoring............................................................................................................................................... 30

6.         Summary of Monitoring Exceedance, Complaints, Notification of Summons and Prosecutions 34

7.         EM&A Site Inspection................................................................................................................................................... 36

8.         Future Key Issues........................................................................................................................................................... 38

9.         Conclusions and Recommendations...................................................................................................................... 40

 

 

Appendix A            Master Programme

 

Appendix B            Overview of Desalination Plant in Tseung Kwan O

 

Appendix C             Summary of Implementation Status of Environmental Mitigation Appendix D            Impact Monitoring Schedule of the Reporting Month

Appendix E            Event/Action Plan for Noise Exceedance

 

Appendix F             Noise Monitoring Equipment Calibration Certificate (Blank) Appendix G            Event/Action Plan for Water Quality Exceedance

Appendix H            Waste Flow Table

Appendix I              Site Inspection Proforma

 Appendix J              Complaint Log


Appendix K                       Impact Monitoring Schedule of Next Reporting Month

Appendix L            Water Quality and Landfill Gas Monitoring Data

Appendix M         HOKLAS Laboratory Certificate

 Appendix N            Water Quality and Landfill Gas Equipment Calibration Certificate

Appendix O            Exceedance Report(s)

 

 

 

 

 


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 23rd 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 January 2022 to 31 January 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 ActiDAFF parapet;

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

-              Construction of Sludge tank and Post Treatment Building (PTB);

-              Construction of On-Site Chlorine Generation (OSCG) Building and carbon dioxide (CO2) tank area;

-              Internal finishing works at Product Water Storage Tank (PWST) and Electrical Building and Main Electrical and Central Chiller Plant Building (MECCP);

-              Construction of manhole and Glass Reinforced Plastic (GRP) pipe installation;

-              Commence construction of Manholes no.15 and no.16 adjacent to ActiDAFF and Reverse Osmosis Area (RO);

-              Construction of first and second floor walls and columns of Administration Building;

-              Construction of reinforced concrete (RC) support of Inspection Corridor;

-              Construction of 1st floor structural wall of Chemical Building;

-              Dewatering, predrill, rock cutting and excavations at Outfall Shaft;

-              Excavation & Lateral Support (ELS) erection and commencement of marine dredging at Intake Shaft;

-              Concrete blinding laying and backfill with aggregate at Intake Shaft;

-              Pipe jacking works at Combined Shaft for Intake & Outfall pipelines;

-              Outfall Shaft - rock coring, chain-cut the bed rock inside the caisson and pumping clean seepage water within silt curtain area

-              Intake Shaft - fitting in waling and welding inside the shaft

-              Intake Shaft - excavate non-MD inside the shaft

-              Intake Shaft - Blinding layer concreting works inside the shaft

-              Intake Shaft - mobilizing vibratory hammer for retrieving 7 nrs. pipe piles

-              Construction of base slab of Pump house

 

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 contract-related 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. Fifty-two (52) of the general water quality monitoring results of suspended solids (SS) obtained had exceeded the Action Level. Thirty-three (33) 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 1, 4, 6, 8, 11, 15, 18, 20, 22, 25, 27, 29 and 31 January 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 January were unrelated to the Contract.

 

A14.ACJCJ’s Environmental Office received a text message on 14 January 2022 from EPD inspector claiming that susceptible oil spillage at the water surface nearby to Outfall Shaft was observed during their routine drone check on 13 January 2022. The message from EPD was relayed to ET by AJCJV on 15 January 2022. Immediate investigation by AJCJV has been made after the acknowledgement of the incident, whilst implementing emergency clean up measure on any residue oil spillage. After investigation, the oil spillage was unlikely originated from the Outfall Shaft. The incident may therefore be considered as non-project related. Detail of the incident could be referring to Appendix O.

 

A15.In this reporting period, 47 times of landfill gas monitoring were recorded at Wan Po Road (Ch1+360 - Ch1+513). No exceedance of action and limit levels for methane, oxygen and carbon dioxide was observed. Monitoring was conducted during excavations at 1m depth or more within the consultation zone and whenever workers entered the excavation on the day.

 

A16.Joint site inspections of the construction work by ET and IEC were carried out on 4, 11, 18, 26 and 31 January 2022 to audit the mitigation measures implementation status. Observations 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:

-              Land Survey;

-              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 carbon dioxide (CO2) Tank area;

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

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

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

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

-              Construction of reinforced concrete (RC) support of Inspection Corridor;

-              Construction of structural wall and Roof of Chemical Building;

-              Outfall Shaft - Dewatering; Predrill, Rock cutting and excavations;

-              Intake shaft - Retrieval of DN 2500 Tunnel Boring Machine (TBM) under water;

-              Pipe jacking at Combined Shaft for Outfall pipelines; and

-              Intake tunnel - Demobilize the jack pipe system and commencement of grouting works.

 

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

-              Construction dust and noise generation from pipe piling driven works, rock cutting works, drilling, 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:

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

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

-              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.

 

 

 

 

 

 


1.     BASIC CONTRACT INFORMATION

 

1.1.      BACKGROUND

The Acciona Agua, S.A. Trading, Jardine Engineering Corporation, Limited and China State Construction Engineering (Hong Kong) Limited As AJC Joint Venture (AJCJV) is contracted to carry out the Design, Build and Operate First Stage of Tseung Kwan O Desalination Plant (DPTKO) under Contract No. 13/WSD/17 (the Contract).

Acuity Sustainability Consulting Limited (ASCL) is commissioned by AJCJV to undertake the Environmental Team (ET) services as required and/or implied, both explicitly and implicitly, in the Environmental Permit (EP), Environmental Impact Assessment Report (EIA Report) (Register No. AEIAR-192/2015) and Environmental Monitoring and Audit Manual (EM&A Manual) for the Contract; and to carry out the Environmental Monitoring and Audit (EM&A) programme in fulfillment of the EIA Report’s EM&A requirements and Contract No. 13/WSD/17 Specification requirements.

Pursuant to the Environmental Impact Assessment Ordinance (EIAO), the Director of Environmental Protection granted the Environmental Permit (No. EP-01/503/2015) and Variation of Environmental Permit (No. EP-01/503/2015/A) to Water Supplies Department (WSD); and granted the Further Environmental Permit (No. FEP-01/503/2015/A) to AJCJV for the Contract.

 

1.2. THE REPORTING SCOPE

This is the 23rd Monthly EM&A Report for the Contract which summarizes the key findings of the EM&A programme during the reporting period from 1 January to 31 January 2022.

 

1.3. CONTRACT ORGANIZATION

The Contract Organization structure for Construction Phase is presented in Figure 1.1.

 

Figure 1.1         Contract Organization Chart


Contact details of the key personnel are presented in Table 1.1 below:

 

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

 

1.4. SUMMARY OF CONSTRUCTION WORKS

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

 


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

-              Land Survey;

-              Construction of ActiDAFF parapet;

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

-              Construction of Sludge tank and Post Treatment Building (PTB);

-              Construction of On-Site Chlorine Generation (OSCG) Building and carbon dioxide (CO2) tank area;

-              Internal finishing works at Product Water Storage Tank (PWST) and Electrical Building and Main Electrical and Central Chiller Plant Building (MECCP);

-              Construction of manhole and Glass Reinforced Plastic (GRP) pipe installation;

-              Commence construction of Manholes no.15 and no.16 adjacent to ActiDAFF and Reverse Osmosis Area (RO);

-              Construction of first and second floor walls and columns of Administration Building;

-              Construction of reinforced concrete (RC) support of Inspection Corridor;

-              Construction of 1st floor structural wall of Chemical Building;

-              Dewatering, predrill, rock cutting and excavations at Outfall Shaft;

-              Excavation & Lateral Support (ELS) erection and commencement of marine dredging at Intake Shaft;

-              Concrete blinding laying and backfill with aggregate at Intake Shaft;

-              Pipe jacking works at Combined Shaft for Intake & Outfall pipelines;

-              Outfall Shaft - rock coring, chain-cut the bed rock inside the caisson and pumping clean seepage water within silt curtain area

-              Intake Shaft - fitting in waling and welding inside the shaft

-              Intake Shaft - excavate non-MD inside the shaft

-              Intake Shaft - Blinding layer concreting works inside the shaft

-              Intake Shaft - mobilizing vibratory hammer for retrieving 7 nrs. pipe piles

-              Construction of base slab of Pump house

 

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

Remarks

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

 

Wastewater Discharge Licence (Land and Marine works)

WT00035775-2020

23/08/2021 -

31/07/2025

 

Chemical Waste Producer Registration

5213-839-A2987-01

Throughout the Contract

 

Construction Noise Permit (24 hrs) -

CNP for general works, TBM at Combined Shaft and marine works

GW-RE1041-21

01/11/2021 -

30/04/2022

 

Billing Account for Disposal of Construction Waste

7036276

Throughout the Contract

 

Vessel CHITs for fill disposal

7039300

*Application for renewal was submitted on 14

December 2021. Application in

progress

 

Dumping at Sea Ordinance (DASO) Permit to dump materials (Category M) at sea

EP/MD/22-083

03/12/2021 -

02/01/2022

 

Dumping at Sea Ordinance (DASO) Permit to dump materials (Category L) at sea

EP/MD/22‐028

02/08/2021 -

01/02/2022

 

 


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 Monitoring Plan

On-going

Landfill Gas

 

Regular Monitoring when Construction Works are within the 250m Consultation Zone

In this reporting period, 47 time of landfill gas monitoring was recorded at Wan Po Road (Ch1+360 - Ch1+513). No exceedance of action and limit levels for methane, oxygen and carbon dioxide was observed. Monitoring was conducted during excavations at 1m depth or more within the consultation zone and

whenever workers entered the excavation on the day.

Environmental Audit

Site Inspection covering Measures of Air Quality, Noise Impact, Water

Quality, Waste, Ecological Quality, Fisheries, Landscape and Visual

On-going

 

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.

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

 

2.1. MONITORING REQUIREMENTS

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.

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.

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.

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.

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.

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

 

2.2. MONITORING LOCATIONS

The monitoring locations should normally be 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.


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

 

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

 


文字方塊: 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

 

 


2.3. IMPACT MONITORING METHODOLOGY

Integrated sound level meter shall be used for the noise monitoring. The meter shall 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 shall be checked using an acoustic calibrator generating a known sound pressure level at a known frequency. Measurements may be 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.

Noise measurements shall not be 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.

Table 2.3           Impact Noise Monitoring Equipment

 

Equipment

Brand and Model

Detection Limit

Sound Level Meter

Nti XL2

30-130 dB(A)

Sound Level Meter Calibrator

Rion NC-74

Nil

Pocket Wind Meter Anemometer

Kestrel 1000 Wind Meter

Nil

 

2.4. ACTION AND LIMIT LEVELS

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 2.4.

 

Table 2.4           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

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

 

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.

 

 

 

2.5.  MONITORING RESULTS AND OBSERVATIONS

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

 

In accordance with the recommendations of the EIA, water quality EM&A 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.

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.

 

In addition, the marine works contractor is required to complete a silt curtain efficiency test for the combined use of floating silt curtain type and cage type silt curtain for dredging at seawater intake to confirm the silt curtain reduction efficiency assumptions of the assessment. The details of testing plan together with the silt curtain deployment plan shall be submitted by the ET to seek approval from the IEC and EPD.

With the onset of marine dredging activities in late April 2021 at Outfall Shaft Area, a silt curtain efficiency test has been conducted at the Outfall Shaft Area on 16th April 2021 at 6 monitoring intervals (08:00, 10:00, 12:00, 14:00, 16:00, 18:00). The baseline monitoring event has been conducted on 10th April 2021 at 5 monitoring locations. Testing protocols and methodologies had followed the guidelines as presented in the EM&A Manual Annex C. Detailed analysis of in-situ and laboratory data was presented in a separate report which has been submitted to EPD after approval by IEC on 31 May 2021. The overall Silt Removal Effectiveness at Outfall Shaft Area for the combined used of cage and floating type silt curtains was 95.28%.

 

3.1.1.         WATER QUALITY PARAMETERS

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 baseline monitoring are listed in Table 3.1.


 

Table 3.1                        Parameters measured in the baseline 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 NOTE2

mg/L

Fe

Anti-scalant as Reactive Phosphorus NOTE2

mg/L

PO4 as P-

NOTE 1: Monitoring of TRC will be conducted when cleaning and sterilization of the new freshwater main is carried out. NOTE 2: The testing methods shall be submitted to EPD for approval prior to the commencement of monitoring programme

 

In addition to the water quality parameters, other relevant data will also be 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.

 

3.1.2.         MONITORING EQUIPMENT

For water quality monitoring, the following equipment will be used:

 

Dissolved Oxygen and Temperature Measuring Equipment - The instrument will be a portable, weatherproof dissolved oxygen measuring instrument complete with cable, sensor, comprehensive operation manuals, and will be operable from a DC power source. It will be 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 shall have 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 shall be 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 will be a portable, weatherproof turbidity- measuring unit complete with cable, sensor and comprehensive operation manuals. The equipment will be operated from a DC power source, it will have a photoelectric sensor capable of measuring turbidity between 0 - 1000 NTU and will be 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 will be 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) will be 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 should be suitably calibrated. The ET shall seek approval for their proposed equipment with the client prior to deployment.

Current Velocity and Direction - No specific equipment is recommended for measuring the current velocity and direction. The environmental contractor shall seek approval of their proposed equipment with the client prior to deployment.

Positioning Device - A Global Positioning System (GPS) shall be used during monitoring to allow accurate recording of the position of the monitoring vessel before taking measurements. The Differential GPS, or equivalent instrument, should be 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, will be used (e.g. Kahlsico Water Sampler 13SWB203 or an approved similar instrument). The water sampler will have 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.

 

3.1.3.         SAMPLING / TESTING PROTOCOLS

All in situ monitoring instruments will be 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 will be checked with certified standard solutions before each use.

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

 

3.1.4.         LABORATORY MEASUREMENT AND ANALYSIS

All laboratory work shall be carried out in a HOKLAS accredited laboratory. Sufficient volume of each water sample shall be collected at the monitoring stations for carrying out the laboratory analyses. Using chain of custody forms, collected water samples will be transferred to an HOKLAS accredited laboratory for immediate processing. The determination work shall start within the next working day after collection of the water samples. The laboratory measurements shall be provided to the client within 5 working days of the sampling event. Analytical methodology and sample preservation of other parameters will be 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 should include 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 shall be in accordance with requirements of HOKLAS or another internationally accredited scheme.

Parameters for laboratory measurements, their standard methods and their 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 (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 17th Ed 2540D

1.0

2.0

+-17%

Total Residual Chlorine (mg/L)

APHA 21st Ed 4500

- Cl G NOTE1

0.1NOTE1

0.2NOTE1

+-10% NOTE1

Iron-soluble

USEPA 6010C NOTE 1

0.2NOTE1

0.2NOTE1

+-25%NOTE1

Anti-scalant as Reactive phosphorus

APHA 4500P: B&F

NOTE1

0.01NOTE1

0.01NOTE1

+-25%NOTE1

NOTE1: The testing methods, Quality Assurance/Quality Control (QA/QC) details, detection limits and accuracy shall be submitted to EPD for approval prior to the commencement of monitoring programme.

 

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

 

3.1.5.         MONITORING LOCATION

The water quality monitoring locations for baseline are in accordance with the EM&A Manual and detailed in Table 3.3 below. A schedule for water quality monitoring shall be prepared by the ET and approved by IEC and EPD prior to the commencement of the monitoring.

Table 3.3           Location of Baseline Water Quality Monitoring Station

 

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


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          Baseline and Impact water quality monitoring locations under EM&A Manual

 

 

 


3.1.6.        SAMPLING FREQUENCY

During periods when there are dredging works, impact monitoring should be undertaken at the monitoring stations as shown in Figure 3.1 and Table 3.3 three days per week during the construction phase after the commencement of marine construction works and dredging activities. Monitoring at each station would be undertaken at both mid-ebb and mid-flood tides on the same day. The tidal range selected for the baseline monitoring will be at least 0.5 m for both flood and ebb tides as far as practicable. The interval between two sets of monitoring would not be 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.

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 will be recorded.

3.1.7.        SAMPLING DEPTHS & REPLICATION

For baseline monitoring, each station will be sampled and measurements/ water samples will be 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 shall be taken. For stations that are less than 6 m in depth, only the surface and seabed sample shall be taken. For in situ measurements, duplicate readings shall be made at each water depth at each station. Duplicate water samples shall be collected at each water depth at each station. All observations and results were recorded in the data record sheets in Appendix L.

3.1.8.           ACTION AND LIMIT LEVELS

The Action and Limit Levels have been set based on the derivation criteria specified in the EM&A Manual, as shown in Table 3.4 below. Based on the baseline water quality monitoring data and the derivation criteria specified in Table 3.4, the Action/Limit Levels have been derived and are presented in Table 3.5.

 

3.2.  MONITORING PROGRAMME

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 monitoring results was presented in Baseline Water Quality Monitoring Report separately.

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

 

 

 

 


Table 3.4           Criteria of Action and Limit Levels for Water Quality

 

Parameters

Action

Limit

Construction Phase Impact Monitoring

DO in mg/L

Surface and Middle

5%-ile of baseline data for surface and middle layer

Bottom

5%-ile of baseline data for bottom layers

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)

≥ 95 %-ile of baseline data or 20% exceedance of value at any impact station compared with corresponding data from control

station

≥ 99 %-ile of baseline data or 30% exceedance of value at any impact station compared with corresponding data from control

station

Turbidity in NTU (Depth-averaged)

≥ 95 %-ile of baseline data or 20% exceedance of value at any impact station compared with corresponding data from control

station

≥ 99 %-ile of baseline data or 30% exceedance of value at any impact station compared with corresponding data from control

station

First-year Operation Phase Monitoring

DO in mg/L

Surface and Middle

5%-ile of baseline data for surface and middle layer

Bottom

5%-ile of baseline data for bottom layers

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)

≥ 95 %-ile of baseline data or 20% exceedance of value at any impact station compared with corresponding data from control station

≥ 99 %-ile of baseline data or 30% exceedance of value at any impact station compared with corresponding data from control station

Turbidity in NTU (Depth-averaged)

≥ 95 %-ile of baseline data or 20% exceedance of value at any impact station compared with corresponding data from control station

≥ 99 %-ile of baseline data or 30% exceedance of value at any impact station compared with corresponding data from control station

Salinity in PSU (Depth-averaged)

109% of baseline level or 9% exceedance of value at any impact station compared with corresponding data from control

station

110% of baseline level 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

 


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.

 

 

3.3.  MONITORING RESULTS AND OBSERVATIONS

General water quality monitoring at the ten monitoring stations (CE, CF, WSR1, WSR2, WSR3, WSR4, WSR16, WSR33, WSR36 and WSR37) were conducted on 1, 4, 6, 8, 11, 13, 15, 18, 20, 22, 25, 27, 29 and 31 January 2022.

 

Fifty-two (52) of the general water quality monitoring results of suspended solids (SS) obtained had exceeded the Action Level. Thirty-three (33) 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.

 

Investigation on the reason of exceedance has been carried out, where the exceedances of SS on1, 4, 6, 8, 11, 15, 18, 20, 22, 25, 27, 29 and 31 January 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.

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)

Surface & Middle

 

Bottom

 

CE

Avg.

32.8

8.8

8.8

8.2

3.3

4.1

21.1

Min.

30.1

8.1

8.1

8.0

2.3

2.5

19.7

Max.

35.1

9.6

9.6

8.5

4.3

12.0

23.1

 

CF

Avg.

32.8

8.7

8.7

8.3

3.9

5.4

21.2

Min.

30.3

8.2

8.2

8.0

2.2

2.5

20.1

Max.

34.9

9.0

9.1

8.5

5.7

22.0

22.9

 

WSR1

Avg.

32.8

8.7

8.6

8.2

2.7

4.4

21.1

Min.

30.3

8.2

8.2

8.0

1.6

2.5

19.6

Max.

35.0

9.4

9.4

8.5

4.0

8.0

22.7

 

WSR2

Avg.

33.0

9.0

8.9

8.3

2.3

5.0

21.2

Min.

31.1

8.3

8.4

8.0

1.5

2.5

19.7

Max.

35.0

9.8

9.9

8.5

3.4

21.0

23.2

 

WSR3

Avg.

32.4

8.7

8.7

8.3

2.7

6.5

23.5

Min.

31.1

7.7

7.7

8.1

1.6

2.5

21.9

Max.

33.3

9.4

9.4

8.5

4.6

23.0

25.8

 

WSR4

Avg.

32.7

8.8

8.8

8.2

2.7

6.4

21.2

Min.

30.6

8.3

8.0

8.0

1.8

2.5

20.0

Max.

35.3

9.6

9.6

8.4

3.8

36.0

22.5

 

WSR16

Avg.

32.2

8.8

8.8

8.3

2.9

6.4

23.6

Min.

31.0

8.1

8.0

8.1

1.7

3.0

22.0

Max.

33.8

9.5

9.5

8.5

4.3

26.0

25.6

 

WSR33

Avg.