CONTENTS

Executive Summary. 1

1....... Introduction. 1

1.1        Background. 1

1.2        Structure of the Report 1

2....... Water Quality Monitoring.. 2

2.1        Monitoring Locations. 2

2.2        Monitoring Methodology. 3

2.2.1        Monitoring Parameters and Frequency. 3

2.2.2        Monitoring Equipment 3

2.2.3        Operational/ Analytical Procedures. 4

2.3        QA/QC Requirements. 9

2.3.1        Calibration of In-situ Instruments. 9

2.3.2        Decontamination Procedures. 9

2.3.3        Sampling Management and Supervision. 9

2.3.4        Quality Control Measures for Sample Testing. 9

2.4        Post-Construction Water Quality Monitoring Results. 9

3....... Conclusion. 14

 

Annexes

Annex A         Calibration Certificates

Annex B         Implementation Schedule

Annex C        Monitoring Schedule

Annex D        Post-construction Water Quality Monitoring Results

Annex E        Graphical Presentation of Post-construction Water Quality Monitoring Results

 

List of Tables

Table 2.1       Location of Water Quality Monitoring Stations. 2

Table 2.2       Water Quality Monitoring Parameters and Frequency. 3

Table 2.3       Water Quality Monitoring Equipment 3

Table 2.4       Action and Limit Levels for Marine Water Quality Monitoring  4

Table 2.5       Event and Action Plan for Marine Water Quality Monitoring  7

Table 2.6       Summary of Monitoring Results for DO, Turbidity and SS  10

 

List of Figures

Figure 1.1      Indicative Location of Key Project Components

Figure 2.1      Water Quality Monitoring Locations

 

Executive Summary

To support the increased use of natural gas in Hong Kong from 2020 onwards, Castle Peak Power Company Limited (CAPCO) and The Hongkong Electric Co., Ltd. (HK Electric) have identified that the development of an offshore liquefied natural gas (LNG) receiving terminal in Hong Kong using Floating Storage and Regasification Unit (FSRU) technology (‘the Project’) presents a viable additional gas supply option that will provide energy security through access to competitive gas supplies from world markets.  The Project will involve the construction and operation of an offshore LNG import facility to be located in the southern waters of Hong Kong, a double berth jetty, and subsea pipelines that connect to the gas receiving stations (GRS) at the Black Point Power Station (BPPS) and the Lamma Power Station (LPS).  In accordance with the Updated EM&A Manual of the Project, a post-construction water quality monitoring was undertaken for the Project upon completion of marine construction activities.

Post-construction water quality monitoring was conducted three times a week for four weeks between 7 November and 2 December 2022 at 35 monitoring stations specified in the Updated EM&A Manual.  Overall, no observable pollution source was recorded at the monitoring stations and no marine construction works were observed in the vicinity of all monitoring stations during the post-construction monitoring period.  The monitoring results are thus considered representative.  The water quality monitoring results showed that the levels of Dissolved Oxygen (DO), Turbidity and Suspended Solids (SS) varied across monitoring stations (both control and impact stations) and over time.  The levels of DO, Turbidity and SS were within the respective ranges obtained in the baseline water quality monitoring conducted in 2019-2020.

Overall, deterioration of water quality and indirect impacts at water and ecological sensitive receivers were not detected.  The construction of the Project did not result in unacceptable water quality impacts to the nearby water and ecological sensitive receivers, which aligns with the EIA study predictions.

1.                  Introduction

1.1             Background

To support the increased use of natural gas in Hong Kong from 2020 onwards, Castle Peak Power Company Limited (CAPCO) and The Hongkong Electric Co., Ltd. (HK Electric) have identified that the development of an offshore liquefied natural gas (LNG) receiving terminal in Hong Kong using Floating Storage and Regasification Unit (FSRU) technology (‘the Project’) presents a viable additional gas supply option that will provide energy security through access to competitive gas supplies from world markets.  The Project will involve the construction and operation of an offshore LNG import facility to be located in the southern waters of Hong Kong, a double berth jetty, and subsea pipelines that connect to the gas receiving stations (GRS) at the Black Point Power Station (BPPS) and the Lamma Power Station (LPS).

The Environmental Impact Assessment (EIA) Report for the Project was submitted to the Environmental Protection Department (EPD) of the HKSAR Government in May 2018. The EIA Report (EIAO Register No. AEIAR-218/2018) was approved by EPD and the associated Environmental Permit (EP) (EP-558/2018) was issued in October 2018. 

An application for Further Environmental Permits (FEPs) were made on 24 December 2019 to demarcate the works between the different parties.  The following FEPs were issued on 17 January 2020 and the EP under EP-558/2018 was surrendered on 5 March 2020. 

§  the double berth jetty at LNG Terminal under the Hong Kong LNG Terminal Limited (HKLTL), joint venture between CAPCO and HK Electric (FEP-01/558/2018/A) ([1]) – construction commenced on 27 November 2020;

§  the subsea gas pipeline for the BPPS and the associated GRS in the BPPS under CAPCO (FEP-03/558/2018/B) ([2]) – construction commenced on 23 September 2020; and

§  the subsea gas pipeline for the LPS and the associated GRS in the LPS under HK Electric (FEP-02/558/2018/A) ([3]) – construction commenced on 13 December 2020.

The location of these components is shown in Figure 1.1.

This Post-Construction Water Quality Monitoring Report is prepared in accordance with the requirements as set out in the Updated EM&A Manual of the Project.

1.2             Structure of the Report

The remainder of the Post-Construction Water Quality Monitoring Report is structured as follows:

§  Section 2 details the monitoring locations, monitoring methodology, QA/QC requirements, and the monitoring results;

§  Section 3 provides the conclusion of this post-construction water quality monitoring.

 

 

2.                  Water Quality Monitoring

In accordance with the Updated EM&A Manual of the Project, post-construction water quality monitoring was conducted three times per week for four weeks upon completion of marine construction activities for the Project, in the same manner as the baseline monitoring, except total residual chlorine (TRC) would not be measured during post-construction monitoring.  Details of the post-construction water quality monitoring under this Project are presented in the following sections.

2.1             Monitoring Locations

Post-construction water quality monitoring was conducted at 35 monitoring stations within five Water Control Zones (WCZs), namely Deep Bay WCZ, North Western WCZ, North Western Supplementary WCZ, Southern WCZ and Second Southern Supplementary WCZ, comprising 22 impact stations, seven ebb-tide control stations and six flood-tide control stations.  The locations of the monitoring stations are presented in Figure 2.1.  The coordinates and description of monitoring stations are summarised in Table 2.1.

Table 2.1      Location of Water Quality Monitoring Stations

Station	Easting	Northing	Description
Monitoring stations within Southern WCZ and Second Southern Supplementary WCZ
IM1	829453	806896	Impact Station for Coastline of South Lamma
IM2	828235	810347	Impact Station for Coastline of North Lamma
IM3	820683	805931	Impact Station for Coastline of South Cheung Chau
IM4	816997	805153	Impact Station for Coastline of South Shek Kwu Chau
IM5	814068	804100	Boundary of South Lantau Marine Park (MP)
IM6	814073	802029	Boundary of South Lantau MP
IM7	811652	802029	Boundary of South Lantau MP
IM8	810833	801430	Boundary of South Lantau MP
IM9	807101	801595	Boundary of South Lantau MP
IM10	803145	806407	Boundary of Southwest Lantau MP
E1	827317	811510	Control Station for Ebb Tide
E2	813367	808213	Control Station for Ebb Tide
E3	802686	804123	Control Station for Ebb Tide
F1	827892	804243	Control Station for Flood Tide
F2	822532	802161	Control Station for Flood Tide
F3	815032	801161	Control Station for Flood Tide
F4	809058	806567	Control Station for Flood Tide
Monitoring stations within Deep Bay WCZ, North Western WCZ, North Western Supplementary WCZ
IM11A	801914	806510	Boundary of Southwest Lantau MP
IM12	801041	807024	Boundary of Southwest Lantau MP
IM13	800386	810750	Boundary of Southwest Lantau MP
IM14	801376	810750	Boundary of Southwest Lantau MP
IM15	804820	821110	Boundary of Sha Chau and Lung Kwu Chau MP
IM16A	805039	824343	Coral Colonies at Pak Chau
IM17	804865	827855	Boundary of Sha Chau and Lung Kwu Chau MP
IM18	806220	827890	Boundary of Sha Chau and Lung Kwu Chau MP
IM19	807274	829250	Impact Station for Coastline of Lung Kwu Tan
IM20A	809445	831728	Impact Station for Coastline of Deep Bay
IM21A	808879	830900	Coral Colony at Artificial Seawall at BPPS
IM22A	808703	830717	Coral Colony at Artificial Seawall at BPPS
E4	801571	811923	Control Station for Ebb Tide
E5	804634	822606	Control Station for Ebb Tide
E6	805418	832113	Control Station for Ebb Tide
E7A	808313	833524	Control Station for Ebb Tide
F5	805185	816591	Control Station for Flood Tide
F6	808812	824266	Control Station for Flood Tide

2.2             Monitoring Methodology

2.2.1       Monitoring Parameters and Frequency

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 highest potential to be affected by the construction works or are a standard check on water quality conditions.  Table 2.2 summarises the monitoring parameters, monitoring period and frequencies of the water quality monitoring.  The measurement of monitoring parameters followed the standard methods and detection limit requirements as stated in Table 5.2 of the Updated EM&A Manual.

Table 2.2      Water Quality Monitoring Parameters and Frequency

Monitoring Station	Parameters	Depth	Frequency and Replication
Impact Stations IM1, IM2, IM3, IM4, IM5, IM6, IM7, IM8, IM9, IM10, IM11A, IM12, IM13, IM14, IM15, IM16A, IM17, IM18, IM19, IM20A, IM21A, IM22A   Control Stations Ebb tide - E1, E2, E3, E4, E5, E6, E7A   Flood tide - F1, F2, F3, F4, F5, F6	·     Dissolved Oxygen (DO) (mg/L) ·     Dissolved Oxygen Saturation (DOS) (%) ·     Temperature (°C) ·     pH ·     Turbidity (NTU) ·     Salinity (ppt) ·     Water depth (m) ·     Suspended Solid (SS) (mg/L)	·     Three water depths: 1 m below sea surface, mid-depth and 1 m above seabed.   ·     If the water depth is less than 3 m, mid-depth sampling only.   ·     If water depth less than 6 m, mid-depth would be omitted.	·     Post-construction monitoring: three days per week, at mid-flood and mid-ebb tides, for four weeks upon completion of marine construction activities.  The interval between two sets of monitoring shall not be less than 36 hours.   ·     Two replicates of in-situ measurements and water samples at each depth at each station.

 

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

2.2.2       Monitoring Equipment

Table 2.3 summarises the equipment used in the monitoring works.  All of the monitoring equipment complied with the requirements as set out in the Updated EM&A Manual.

Table 2.3      Water Quality Monitoring Equipment

Equipment	Brand and Model
Water Sampling Equipment	Rosette multibottle array water sampler with Niskin 2L samplers Wildlife Supply Company, 2.2L water sampler
Positioning Device	C-Nav GcGPS Positioning System Furuno, GPS Navigator GP-170 Garmin, eTrex series
Water Depth Gauge	Knudsen 320M Lowrance, Mark 5x Garmin, Striker series
Equipment for Dissolved Oxygen, Temperature, Turbidity, pH and Salinity measurements	YSI 6820, S/N: MPP 37 YSI ProDSS, S/N: 16H104233, 16H104234, 17E100747
Equipment for Current Velocity and Direction measurements	Workhorse Sentinel ADCP, Self-contained 1,200 and 600 kHz Sontek, S/N: 5649, 6738

2.2.3       Operational/ Analytical Procedures

At each monitoring station, two consecutive measurements of DO level, DO Saturation, Temperature, Turbidity, Salinity and pH were taken at each sampling depth.  Where the difference in the value between the first and second readings of each set was more than 25% of the value of the first reading, the reading was discarded and further readings were taken.  Two water samples were collected for laboratory analysis of SS content.  Following sample collection, water samples were stored in high density polythene bottles (1L) with no preservatives added, packed in ice (cooled to 4°C without being frozen) and kept in dark during both on-site temporary storage and transfer to the testing laboratory.  The samples were delivered to the laboratory as soon as possible and the laboratory determination works started within 24 hours after collection of the water samples. 

The testing of SS for all monitoring stations was conducted by a Hong Kong Laboratory Accreditation Scheme (HOKLAS) accredited laboratory, ALS Technichem (HK) Pty Ltd. (HOKLAS Registration No. 066).  Comprehensive quality assurance and control procedures were in place in order to ensure quality and consistency in results.

2.2.4       Action and Limit Levels for Marine Water Quality Monitoring

The Action and Limit Levels for marine water quality monitoring have been established based on the baseline marine water quality monitoring data in accordance with the Updated EM&A Manual.  Action and Limit Levels of key assessment parameters for construction phase marine water quality monitoring including DO, turbidity and SS are summarised in Table 2.4.

Table 2.4      Action and Limit Levels for Marine Water Quality Monitoring

Parameter	Action Level		Limit Level
Group 1 – During construction at the pipeline shore approach at LPS (KP17.4 - 18.2), West Lamma Channel (KP14.5 - 17.4)
DO in mg L-1 a	Surface and Middle 4.2 mg L-1   Bottom 2.4 mg L-1	Surface and Middle 2.9 mg L-1   Bottom 1.6 mg L-1
Turbidity in NTU (Depth-averaged b) c	14.4 NTU, and 120% of the relevant control station's turbidity at the same tide of the same day	19.9 NTU, and 130% of the relevant control station's turbidity at the same tide of the same day
SS in mg L-1 (Depth-averaged b) c	20.8 mg L-1, and 120% of the relevant control station's SS at the same tide of the same day	29.6 mg L-1, and 130% of the relevant control station's SS at the same tide of the same day
Group 2 – During construction at the Double Berth Jetty to West Lamma Channel (KP0.0 - 14.5)
DO in mg L-1 a	Surface and Middle 3.4 mg L-1   Bottom 1.8 mg L-1	Surface and Middle 2.4 mg L-1   Bottom 1.4 mg L-1
Turbidity in NTU (Depth-averaged b) c	17.1 NTU, and 120% of the relevant control station's turbidity at the same tide of the same day	26.8 NTU, and 130% of the relevant control station's turbidity at the same tide of the same day
SS in mg L-1 (Depth-averaged b) c	25.7 mg L-1, and 120% of the relevant control station's SS at the same tide of the same day	37.1 mg L-1, and 130% of the relevant control station's SS at the same tide of the same day
Group 3 – During construction at the Jetty Approach (KP0.0 - 5.0), South of Soko Islands (KP5.0 - 8.9), Southwest of Soko Islands (KP8.9 - 12.1)
DO in mg L-1 a	Surface and Middle 4.1 mg L-1   Bottom 2.7 mg L-1	Surface and Middle 3.0 mg L-1   Bottom 2.0 mg L-1
Turbidity in NTU (Depth-averaged b) c	17.0 NTU, and 120% of the relevant control station's turbidity at the same tide of the same day	30.9 NTU, and 130% of the relevant control station's turbidity at the same tide of the same day
SS in mg L-1 (Depth-averaged b) c	22.3 mg L-1, and 120% of the relevant control station's SS at the same tide of the same day	36.9 mg L-1, and 130% of the relevant control station's SS at the same tide of the same day
Group 4 – During construction at the Adamasta Channel (KP12.1 - 15.6), Southwest Lantau (KP15.6 - 21.3)
DO in mg L-1 a	Surface and Middle 3.4 mg L-1   Bottom 2.8 mg L-1	Surface and Middle 2.5 mg L-1   Bottom 2.0 mg L-1
Turbidity in NTU (Depth-averaged b) c	63.1 NTU, and 120% of the relevant control station's turbidity at the same tide of the same day	165.7 NTU, and 130% of the relevant control station's turbidity at the same tide of the same day
SS in mg L-1 (Depth-averaged b) c	75.4 mg L-1, and 120% of the relevant control station's SS at the same tide of the same day	121.8 mg L-1, and 130% of the relevant control station's SS at the same tide of the same day
Group 5 – During construction at the West of Tai O to West of HKIA (KP21.3 - 31.5)
DO in mg L-1 a	Surface and Middle 4.6 mg L-1   Bottom 4.0 mg L-1	Surface and Middle 4.0 mg L-1   Bottom 2.0 mg L-1
Turbidity in NTU (Depth-averaged b) c	31.9 NTU, and 120% of the relevant control station's turbidity at the same tide of the same day	46.6 NTU, and 130% of the relevant control station's turbidity at the same tide of the same day
SS in mg L-1 (Depth-averaged b) c	64.9 mg L-1, and 120% of the relevant control station's SS at the same tide of the same day	72.5 mg L-1, and 130% of the relevant control station's SS at the same tide of the same day
Group 6 – During construction at the West of HKIA to Lung Kwu Chau (KP31.5 - 37.5)
DO in mg L-1 a	Surface and Middle 4.4 mg L-1   Bottom 3.9 mg L-1	Surface and Middle 3.9 mg L-1   Bottom 2.0 mg L-1
Turbidity in NTU (Depth-averaged b) c	30.7 NTU, and 120% of the relevant control station's turbidity at the same tide of the same day	47.0 NTU, and 130% of the relevant control station's turbidity at the same tide of the same day
SS in mg L-1 (Depth-averaged b) c	49.2 mg L-1, and 120% of the relevant control station's SS at the same tide of the same day	74.0 mg L-1, and 130% of the relevant control station's SS at the same tide of the same day
Group 7 – During construction at the Lung Kwu Chau to Urmston Anchorage (37.5 - 41.1), Urmston Road (KP41.1 - 42.9)
DO in mg L-1 a	Surface and Middle 3.8 mg L-1   Bottom 3.1 mg L-1	Surface and Middle 3.4 mg L-1   Bottom 2.0 mg L-1
Turbidity in NTU (Depth-averaged b) c	34.5 NTU, and 120% of the relevant control station's turbidity at the same tide of the same day	79.2 NTU, and 130% of the relevant control station's turbidity at the same tide of the same day
SS in mg L-1 (Depth-averaged b) c	37.8 mg L-1, and 120% of the relevant control station's SS at the same tide of the same day	98.2 mg L-1, and 130% of the relevant control station's SS at the same tide of the same day
Group 8 – During construction at the West of BPPS (KP42.9 - 44.9), Pipeline shore approach at BPPS (KP44.9 - 45.0)
DO in mg L-1 a	Surface and Middle 4.3 mg L-1   Bottom 3.6 mg L-1	Surface and Middle 3.4 mg L-1   Bottom 2.0 mg L-1
Turbidity in NTU (Depth-averaged b) c	34.3 NTU, and 120% of the relevant control station's turbidity at the same tide of the same day	58.5 NTU, and 130% of the relevant control station's turbidity at the same tide of the same day
SS in mg L-1 (Depth-averaged b) c	42.4 mg L-1, and 120% of the relevant control station's SS at the same tide of the same day	78.2 mg L-1, and 130% of the relevant control station's SS at the same tide of the same day
Notes: a.     For DO, non-compliance of the water quality limits occurs when monitoring result is lower than the limits. b.     “Depth-averaged” is calculated by taking the arithmetic means of reading of all three depths. c.     For Turbidity and SS, non-compliance of the water quality limits occurs when monitoring result is higher than the limits.

The Event and Action Plan for marine water quality monitoring is provided in Table 2.5.

Table 2.5      Event and Action Plan for Marine Water Quality Monitoring

Event	Action
	ET	IEC	Contractor(s)	Project Proponents
Action Level being exceeded by one sampling day	1.      Repeat in-situ measurement to confirm findings; 2.      Check monitoring data, plant, equipment and Contractor(s)’s working methods;        3.      Identify source(s) of impact and record in notification of exceedance; 4.      Inform IEC, Contractor(s) and Project Proponents.	1.      Check monitoring data submitted by ET and Contractor(s)’s working methods.	1.      Confirm receipt of notification of exceedance in writing; 2.      Check plant and equipment and rectify unacceptable practice.	1.      Confirm receipt of notification of exceedance in writing.
Action Level being exceeded by two or more consecutive sampling days	1.      Repeat in-situ measurement to confirm findings; 2.      Check monitoring data, plant, equipment and Contractor(s)’s working methods; 3.      Identify source(s) of impact and record in notification of exceedance; 4.      Inform IEC, Contractor(s) and Project Proponents; 5.      Discuss with IEC and Contractor(s) on additional mitigation measures and ensure that they are implemented.	1.      Check monitoring data submitted by ET and Contractor(s)’s working methods; 2.      Discuss with ET and Contractor(s) on additional mitigation measures and advise Project Proponents accordingly; 3.      Assess the effectiveness of the implemented mitigation measures.	1.      Confirm receipt of notification of exceedance in writing; 2.      Check plant and equipment and rectify unacceptable practice; 3.      Consider changes of working methods; 4.      Discuss with ET and IEC on additional mitigation measures and propose them to Project Proponents within 3 working days; 5.      Implement the agreed mitigation measures.	1.      Confirm receipt of notification of exceedance in writing; 2.      Discuss with the IEC on the proposed additional mitigation measures and agree on the mitigation measures to be implemented; 3.      Ensure additional mitigation measures are properly implemented.
Limit Level being exceeded by one sampling day	1.      Repeat in situ measurement to confirm findings; 2.      Check monitoring data, plant, equipment and Contractor(s)’s working methods; 3.      Identify source(s) of impact and record in notification of exceedance; 4.      Inform IEC, Contractor(s), Project Proponents and EPD; 5.      Discuss with IEC and Contractor(s) on additional mitigation measures and ensure that they are implemented.	1.      Check monitoring data submitted by ET and Contractor(s)’s working methods; 2.      Discuss with ET and Contractor(s) on additional mitigation measures and advise Project Proponents accordingly; 3.      Assess the effectiveness of the implemented mitigation measures.	1.      Confirm receipt of notification of exceedance in writing; 2.      Check plant and equipment and rectify unacceptable practice; 3.      Critically review the need to change working methods; 4.      Discuss with ET and IEC on additional mitigation measures and propose them to Project Proponents within 3 working days; 5.      Implement the agreed mitigation measures.	1.      Confirm receipt of notification of exceedance in writing; 2.      Discuss with the IEC on the proposed additional mitigation measures and agree on the mitigation measures to be implemented; 3.      Ensure additional mitigation measures are properly implemented; 4.      Request Contractor(s) to critically review the working methods.
Limit Level being exceeded by two or more consecutive sampling days	1.      Repeat in situ measurement to confirm findings; 2.      Check monitoring data, plant, equipment and Contractor(s)’s working methods; 3.      Identify source(s) of impact and record in notification of exceedance; 4.      Inform IEC, Contractor(s), Project Proponents and EPD; 5.      Discuss with IEC and Contractor(s) on additional mitigation measures and ensure that they are implemented.	1.      Check monitoring data submitted by ET and Contractor(s)’s working methods; 2.      Discuss with ET and Contractor(s) on additional mitigation measures and advise Project Proponents accordingly; 3.      Assess the effectiveness of the implemented mitigation measures.	1.      Confirm receipt of notification of exceedance in writing; 2.      Check plant and equipment and rectify unacceptable practice; 3.      Critically review the need to change working methods; 4.      Discuss with ET and IEC on additional mitigation measures and propose them to Project Proponents within 3 working days; 5.      Implement the agreed mitigation measures; 6.      As directed by Project Proponents, slow down or stop all or part of the marine construction works until no exceedance of Limit Level.	1.      Confirm receipt of notification of exceedance in writing; 2.      Discuss with the IEC on the proposed additional mitigation measures and agree on the mitigation measures to be implemented; 3.      Ensure additional mitigation measures are properly implemented; 4.      Request Contractor(s) to critically review the working methods; 5.      Consider and instruct, if necessary, the Contractor(s) to slow down or to stop all or part of the marine construction works until no exceedance of Limit Level.

2.3             QA/QC Requirements

2.3.1       Calibration of In-situ Instruments

In situ monitoring equipment for the measurement of temperature, dissolved oxygen, turbidity, pH and salinity was checked, calibrated and certified by a laboratory accredited under HOKLAS before use.  Copies of the calibration certificates for the measuring equipment for DO, Temperature, Turbidity, pH and Salinity are attached in Annex A.  The in situ monitoring equipment for the measurement of temperature, dissolved oxygen, turbidity, pH and salinity was subsequently re-calibrated every three months throughout the water quality monitoring.  Responses of sensors and electrodes were checked with certified standard solutions before each use.  Wet bulb calibrations for dissolved oxygen meter were carried out before commencement of monitoring and after completion of all measurements each day. 

On-site calibration of field equipment followed 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 also made available to ensure monitoring could proceed uninterrupted even when equipment is under maintenance, calibration etc.

2.3.2       Decontamination Procedures

Water sampling equipment used during the course of the monitoring was decontaminated by manual washing and rinsed with clean seawater/distilled water after each sampling event.  All disposable equipment was discarded after sampling.

2.3.3       Sampling Management and Supervision

All sampling bottles were labelled with the sample ID (including the indication of sampling station and tidal stage e.g. IM1_ME_S_R1), laboratory number and sampling date.  All water samples were handled under chain of custody protocols and relinquished to the laboratory representatives at locations specified by the laboratory.  

2.3.4       Quality Control Measures for Sample Testing

The samples testing were performed by ALS Technichem (HK) Pty Ltd.  The following quality control programme was performed by the laboratory for every batch of 20 samples:

§  One method blank; and

§  One set of quality control (QC) samples (including method QC and sample duplicate).

2.4             Implementation Status of Environmental Mitigation Measures

A summary of the environmental mitigation measures as recommended in the approved EIA Report and the relevant environmental requirements in contract documents is presented in the Environmental Mitigation Implementation Schedule (EMIS) (see Annex B).  The necessary mitigation measures were implemented properly for the construction of the Project.

2.5             Post-Construction Water Quality Monitoring Results

Post-construction water quality monitoring was conducted three times per week for 4 weeks between 7 November and 2 December 2022 at 35 stations. The detailed monitoring schedule is shown in Annex C.  The monitoring results with weather and sea conditions at each monitoring day are shown in Annex D.  Graphical presentation of water quality monitoring results is given in Annex E.  The water quality monitoring results for DO, Turbidity and SS are summarised in Table 2.6.   

Table 2.6      Summary of Monitoring Results for DO, Turbidity and SS

Station	DO (Surface & Middle) (mg/L)		DO (Bottom) (mg/L)		Turbidity (NTU)		SS (mg/L)
	Ebb Tide	Flood Tide	Ebb Tide	Flood Tide	Ebb Tide	Flood Tide	Ebb Tide	Flood Tide
E1	6.5±0.7 (5.4 - 8.3)	6.5±0.8 (5.8 - 9.0)	6.5±0.6 (5.8 - 8.2)	6.6±0.7 (5.8 - 8.6)	4.6±1.8 (1.1 - 9.9)	4.9±2.0 (1.2 - 9.9)	5.5±1.8 (2.7 - 11.5)	4.8±1.9 (2.3 - 9.0)
E2	7.3±1.0 (6.0 - 9.8)	7.6±1.4 (6.7 - 12.3)	7.2±1.0 (5.8 - 9.6)	7.4±1.0 (6.5 - 9.7)	5.3±3.7 (1.0 - 14.9)	6.7±5.0 (0.6 - 25.7)	7.1±4.3 (2.9 - 18.9)	6.3±2.5 (3.1 - 13.6)
E3	7.1±0.7 (6.2 - 9.1)	7.3±0.7 (6.7 - 9.1)	7.0±0.8 (6.0 - 9.0)	7.2±0.7 (6.6 - 8.9)	8.0±5.7 (1.0 - 22.5)	10.3±6.8 (1.8 - 25.1)	7.5±4.9 (2.6 - 20.2)	7.8±6.2 (3.4 - 30.2)
E4	6.9±0.7 (5.9 - 8.9)	7.0±0.7 (6.4 - 9.2)	6.8±0.7 (5.9 - 8.5)	7.0±0.6 (6.4 - 8.8)	11.5±8.7 (1.3 - 33.9)	9.4±7.9 (1.5 - 29.8)	12.3±14.5 (2.4 - 85.2)	9.6±7.6 (2.8 - 29.2)
E5	6.8±0.4 (6.3 - 8.4)	6.5±0.5 (6.1 - 8.0)	6.8±0.4 (6.3 - 7.8)	6.5±0.5 (6.1 - 7.8)	11.4±10.5 (2.1 - 52.1)	14.4±9.3 (3.3 - 45.1)	13.8±12.7 (2.4 - 61.0)	17.2±10.6 (3.2 - 55.3)
E6	6.4±0.2 (6.0 - 6.9)	6.4±0.4 (5.8 - 7.4)	6.2±0.2 (6.0 - 6.6)	6.3±0.4 (5.7 - 7.3)	10.3±8.0 (1.6 - 36.0)	16.7±12.1 (3.3 - 48.4)	12.7±10.5 (2.8 - 41.1)	19.2±14.2 (3.3 - 56.1)
E7A	6.3±0.2 (6.1 - 6.7)	6.5±0.5 (5.8 - 7.5)	6.3±0.2 (6.0 - 6.6)	6.3±0.4 (5.8 - 7.3)	4.8±1.6 (2.4 - 7.8)	8.7±4.9 (3.4 - 18.4)	6.2±2.3 (2.4 - 11.9)	10.2±5.5 (3.7 - 23.2)
F1	6.9±0.7 (6.2 - 8.9)	7.2±0.8 (6.4 - 9.6)	6.8±0.7 (5.8 - 8.6)	7.2±0.8 (6.4 - 9.4)	4.2±2.3 (1.4 - 8.1)	4.3±2.0 (1.2 - 9.9)	5.3±1.5 (1.4 - 8.9)	5.2±1.9 (2.0 - 8.7)
F2	6.9±0.8 (5.8 - 8.9)	7.1±0.8 (6.2 - 9.7)	6.9±0.7 (6.0 - 8.6)	6.9±0.7 (5.9 - 8.8)	4.6±2.4 (1.2 - 13.2)	4.9±2.6 (1.1 - 13.3)	4.9±1.8 (1.1 - 9.7)	5.4±2.0 (2.1 - 9.3)
F3	7.2±0.7 (6.5 - 9.4)	7.2±0.9 (6.4 - 9.6)	7.2±0.5 (6.7 - 8.7)	7.1±0.7 (6.5 - 9.1)	4.4±2.1 (1.1 - 9.7)	4.8±2.1 (1.7 - 8.9)	5.4±1.9 (2.0 - 8.8)	5.4±2.1 (2.3 - 10.5)
F4	7.3±0.9 (6.4 - 9.6)	7.5±1.1 (6.6 - 10.3)	7.2±0.9 (6.2 - 9.4)	7.3±0.9 (6.6 - 9.6)	5.5±4.4 (0.6 - 17.8)	7.7±6.1 (1.7 - 24.1)	6.9±4.8 (2.6 - 21.9)	8.7±7.1 (2.9 - 31.5)
F5	7.0±1.0 (6.0 - 9.8)	7.0±1.0 (6.4 - 9.9)	6.8±0.7 (6.0 - 8.7)	6.9±0.9 (6.3 - 9.7)	9.3±7.1 (1.5 - 29.4)	10.1±8.3 (2.1 - 34.1)	10.7±8.0 (2.2 - 33.2)	14.7±14.2 (2.2 - 51.8)
F6	6.5±0.3 (6.1 - 7.5)	6.5±0.4 (6.0 - 7.4)	6.4±0.2 (6.0 - 6.9)	6.3±0.3 (5.9 - 6.8)	10.4±13.3 (1.9 - 66.8)	13.9±10.1 (2.3 - 49.5)	11.0±13.8 (1.9 - 81.8)	17.2±12.8 (3.0 - 64.1)
IM1	7.1±0.6 (6.2 - 8.8)	6.9±0.9 (5.9 - 9.7)	7.1±0.5 (6.3 - 8.4)	6.9±0.8 (5.9 - 8.9)	3.9±1.9 (1.1 - 9.3)	4.9±2.6 (1.8 - 15.9)	5.2±2.3 (1.6 - 10.2)	5.5±1.5 (2.1 - 8.4)
IM2	7.1±0.7 (6.0 - 9.0)	7.2±0.7 (6.5 - 8.9)	7.0±0.8 (6.0 - 8.9)	7.1±0.7 (6.5 - 8.8)	11.3±8.4 (2.3 - 37.6)	11.0±6.4 (2.5 - 23.8)	9.7±6.8 (2.1 - 37.6)	10.1±6.1 (2.0 - 23.6)
IM3	6.9±0.7 (6.0 - 8.9)	7.1±0.7 (6.5 - 8.9)	6.9±0.7 (6.0 - 8.8)	7.2±0.7 (6.5 - 8.8)	20.9±15.8 (2.7 - 70.5)	16.1±13.7 (2.2 - 56.4)	33.2±30.7 (2.4 - 130.0)	22.7±29.8 (2.2 - 136.0)
IM4	7.0±0.8 (6.0 - 9.2)	7.0±0.6 (6.5 - 8.9)	7.0±0.7 (6.0 - 9.0)	7.0±0.6 (6.6 - 8.7)	12.6±8.8 (1.2 - 48.4)	14.9±9.5 (1.2 - 38.8)	13.2±11.6 (2.3 - 59.4)	17.2±20.2 (2.3 - 100.0)
IM5	6.9±0.8 (6.1 - 9.1)	7.0±0.7 (6.5 - 9.3)	6.9±0.7 (6.0 - 8.9)	6.9±0.6 (6.4 - 8.5)	11.3±10.8 (0.8 - 54.5)	13.9±10.9 (1.1 - 36.3)	9.8±5.5 (3.3 - 25.7)	13.3±15.7 (2.5 - 58.0)
IM6	6.9±0.7 (6.0 - 8.8)	7.0±0.7 (6.4 - 9.1)	6.8±0.7 (6.0 - 8.6)	6.9±0.6 (6.4 - 8.5)	11.8±14.1 (1.3 - 76.7)	11.2±9.3 (1.3 - 34.4)	15.2±23.8 (2.7 - 156.0)	9.9±8.7 (2.2 - 35.7)
IM7	6.8±0.5 (6.3 - 8.6)	6.6±0.5 (6.1 - 8.2)	6.7±0.5 (6.3 - 8.1)	6.6±0.5 (6.1 - 8.0)	8.8±5.5 (1.8 - 27.6)	14.5±8.3 (3.8 - 31.4)	10.5±6.6 (2.3 - 30.2)	18.1±10.2 (5.4 - 37.4)
IM8	6.8±0.5 (6.2 - 8.4)	6.5±0.4 (5.9 - 7.4)	6.7±0.5 (6.3 - 8.1)	6.5±0.4 (5.9 - 7.4)	11.7±7.7 (1.7 - 33.2)	13.9±6.7 (2.7 - 28.9)	13.9±9.3 (2.0 - 44.0)	16.5±8.2 (3.1 - 33.5)
IM9	6.6±0.3 (6.0 - 7.4)	6.6±0.5 (6.1 - 7.7)	6.5±0.3 (6.0 - 7.4)	6.4±0.4 (5.9 - 7.3)	10.3±6.7 (2.0 - 31.8)	12.1±7.5 (2.7 - 36.6)	13.2±8.8 (3.2 - 40.2)	11.7±7.7 (2.2 - 40.2)
IM10	6.4±0.3 (6.0 - 7.4)	6.4±0.4 (5.8 - 7.8)	6.3±0.5 (5.8 - 7.6)	6.1±0.3 (5.8 - 6.7)	8.6±5.3 (2.6 - 22.8)	14.2±15.1 (2.8 - 91.7)	10.4±6.2 (2.3 - 28.8)	16.5±17.0 (3.6 - 114.0)
IM11A	6.4±0.2 (6.1 - 6.9)	6.4±0.3 (6.0 - 7.5)	6.2±0.2 (5.9 - 6.6)	6.2±0.2 (5.8 - 6.6)	6.4±4.5 (2.1 - 26.9)	14.0±13.6 (2.5 - 72.9)	8.3±5.0 (3.0 - 31.7)	16.7±14.8 (2.8 - 73.0)
IM12	6.9±0.6 (6.2 - 8.4)	6.9±0.9 (6.0 - 9.8)	6.9±0.5 (6.2 - 8.2)	6.8±1.0 (5.9 - 9.7)	5.0±2.4 (1.0 - 10.0)	4.4±1.9 (1.8 - 9.1)	5.8±1.6 (2.6 - 9.0)	5.3±1.8 (2.1 - 9.2)
IM13	6.3±0.2 (6.0 - 6.7)	6.4±0.4 (6.0 - 7.6)	6.3±0.1 (6.1 - 6.6)	6.3±0.2 (5.8 - 6.8)	4.4±1.4 (2.1 - 7.0)	12.1±9.3 (2.7 - 45.5)	5.7±1.8 (2.1 - 9.2)	15.0±11.7 (3.1 - 62.1)
IM14	6.2±0.2 (5.9 - 6.6)	6.5±0.2 (6.2 - 7.1)	6.3±0.2 (6.0 - 6.6)	6.4±0.3 (6.0 - 7.0)	5.8±2.1 (2.2 - 13.2)	12.1±7.1 (4.4 - 26.1)	7.2±2.4 (2.9 - 15.2)	15.3±9.4 (4.6 - 40.3)
IM15	6.4±0.2 (6.1 - 6.7)	6.5±0.4 (6.1 - 7.5)	6.4±0.2 (6.1 - 6.7)	6.4±0.3 (5.8 - 6.9)	7.8±3.0 (2.6 - 12.8)	10.7±7.7 (3.6 - 33.0)	10.0±4.2 (2.8 - 16.7)	13.0±10.4 (3.2 - 44.6)
IM16A	7.1±0.7 (6.2 - 9.0)	7.3±0.8 (6.3 - 9.5)	7.1±0.6 (6.3 - 8.7)	7.2±0.7 (6.3 - 8.9)	4.0±1.9 (1.0 - 9.2)	4.4±2.5 (1.0 - 11.9)	5.6±1.9 (2.2 - 10.8)	5.1±1.8 (2.3 - 9.7)
IM17	7.0±0.9 (5.8 - 9.6)	7.0±0.9 (5.8 - 9.5)	7.0±0.9 (5.9 - 9.1)	7.0±0.7 (5.9 - 8.5)	3.9±1.8 (1.0 - 10.8)	4.7±2.3 (1.6 - 10.6)	5.0±1.7 (2.1 - 8.8)	4.9±2.1 (2.0 - 9.6)
IM18	7.0±0.9 (5.9 - 9.5)	7.1±1.0 (5.8 - 9.7)	7.0±0.8 (5.9 - 8.9)	7.0±0.8 (5.8 - 9.0)	4.7±1.7 (1.6 - 9.6)	4.2±1.9 (1.6 - 8.5)	5.3±1.8 (2.5 - 9.6)	5.4±3.3 (2.3 - 26.5)
IM19	7.2±0.7 (6.3 - 9.3)	7.1±1.0 (5.8 - 9.7)	7.3±0.5 (6.7 - 8.9)	7.0±0.9 (5.8 - 9.0)	4.5±1.9 (1.1 - 10.0)	4.8±2.6 (1.0 - 13.4)	5.7±1.7 (2.1 - 9.0)	5.5±2.2 (2.8 - 15.8)
IM20A	7.0±0.8 (5.8 - 9.1)	7.1±0.8 (6.0 - 9.2)	6.9±0.8 (5.8 - 8.7)	7.1±0.7 (6.1 - 8.7)	4.5±2.3 (1.0 - 10.2)	4.7±2.4 (1.4 - 11.4)	5.2±1.6 (2.4 - 9.0)	5.6±2.5 (2.3 - 11.8)
IM21A	7.1±0.7 (6.3 - 9.1)	7.3±0.7 (6.5 - 9.4)	7.1±0.6 (6.3 - 8.4)	7.3±0.6 (6.7 - 8.9)	4.5±2.4 (1.0 - 11.5)	4.8±2.0 (1.0 - 9.4)	5.5±1.9 (2.3 - 9.1)	5.1±1.9 (2.6 - 9.3)

Note: (1) Averaged value ± standard deviation and the range of values (in bracket) are presented in each cell.

 

The water quality monitoring results showed that the levels of DO, Turbidity and SS varied across monitoring stations (both control and impact stations) and over time.  The levels of DO, Turbidity and SS were within the respective ranges obtained in the baseline water quality monitoring conducted in 2019-2020.

It is noticed that some high levels of Turbidity and SS were occasionally recorded during the monitoring.  Repeat in-situ measurement was conducted during the monitoring to confirm findings.  Upon checking the field records, no marine construction works were observed in the vicinity of all monitoring stations during the monitoring period.  No other external factors (e.g. surface runoff from nearby landmass, adverse weather) were identified that might affect water quality at the monitoring stations during the post-construction monitoring period.  Such high levels of Turbidity and SS were within their respective ranges of EPD routine water quality monitoring data and the baseline water quality monitoring of the Project as discussed in the Baseline Monitoring Report ⁽[4]⁾.

Overall, the monitoring results for both impact and control stations are considered representative of the water quality of the Project area.  Deterioration of water quality and indirect impacts at water and ecological sensitive receivers were not detected.  The construction of the Project did not result in unacceptable water quality impacts to the nearby water and ecological sensitive receivers, which aligns with the EIA study predictions.

3.                  Conclusion

In accordance with the Updated EM&A Manual of the Project, post-construction water quality monitoring was conducted three times per week for four weeks upon completion of marine construction activities for the Project, in the same manner as the baseline monitoring, except TRC would not be measured during post-construction monitoring.

Post-construction water quality monitoring was conducted three times a week for four weeks between 7 November and 2 December 2022 at 35 monitoring stations specified in the Updated EM&A Manual.  Overall, no observable pollution source was recorded at the monitoring stations and no marine construction works were observed in the vicinity of all monitoring stations during the post-construction monitoring period.  The monitoring results are thus considered representative.  The water quality monitoring results showed that the levels of DO, Turbidity and SS varied across monitoring stations (both control and impact stations) and over time.  The levels of DO, Turbidity and SS were within the respective ranges obtained in the baseline water quality monitoring conducted in 2019-2020.

Overall, deterioration of water quality and indirect impacts at water and ecological sensitive receivers were not detected.  The construction of the Project did not result in unacceptable water quality impacts to the nearby water and ecological sensitive receivers, which aligns with the EIA study predictions.