LAMMA POWER STATION EXTENSION

Supply and Installation of Submarine Gas Pipeline

 

 

 

Water Quality Monitoring During Post-Trenching Works

Impact Monitoring Report

 

June 2005

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

30/06/05

Issued for comments

WK

 

 

 

REV

DATE

DESCRIPTION

PREPARED

 CHECKED

APPROVED

PURCHASER

STATUS CODE :  A = Issued for comments – B = Issued for approval – C = Approved for Construction

 

TOTAL OR PARTIAL REPRODUCTION AND/OR UTILIZATION OF THIS DOCUMENT ARE FORBIDDEN

WITHOUT PRIOR WRITTEN AUTHORIZATION OF THE OWNER

                   


                  

THE HONGKONG ELECTRIC CO., LTD.

LAMMA POWER STATION EXTENSION

Supply and Installation of Submarine Gas Pipeline

Contract No. 03/9008

 

 

Doc. No.: LTLD-32-1-138-G

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Saipem Asia Sdn. Bhd

 

 

 

 

 

 

 

 

 

Lamma Power Station Extension

– Supply and Installation

of Submarine Gas Pipeline

 

Water Quality Monitoring During Post-Trenching Works

Impact Monitoring Report (Version 0.A)

 

June 2005

 

 

 

 

 

 

 

Approved By

 

 

(Project Director: Dr. HF Chan)

 

REMARKS:

 

The information supplied and contained within this report is, to the best of our knowledge, correct at the time of printing.

 

CINOTECH accepts no responsibility for changes made to this report by third parties.

 

 

CINOTECH CONSULTANTS LTD

Room 1602-1610, Delta House,

3 On Yiu Street,

Shatin, NT, Hong Kong

Tel: (852) 2151 2083    Fax: (852) 3107 1388

Email: info@cinotech.com.hk

 

 

Table of contents

 

 

EXECUTIVE SUMMARY.. 1

Introduction. 1

Environmental Monitoring Works. 1

Complaints and Prosecutions. 2

Future Key Issues. 2

1      INTRODUCTION.. 3

Background. 3

Project Organizations. 4

2      Water Quality Monitoring.. 5

Monitoring Requirements. 5

Monitoring Parameters. 5

Monitoring Equipment 5

Monitoring Locations. 6

Monitoring Frequency and Duration. 7

Monitoring Methodology, Calibration Details and QA/QC Procedures. 7

Results and Observations. 8

3      ENVIRONMENTAL AUDIT.. 9

Review of Environmental Monitoring Procedures. 9

Implementation Status of Event Action Plans. 9

Implementation Status of Mitigation Measures. 9

Summary of Non-compliance of the Environmental Quality Performance Limit 9

Summary of Complaints and Prosecution. 9

4      FUTURE KEY ISSUES.. 10

Key Issues for the Coming Month. 10

Monitoring Schedule for the Next Month. 10

5      CONCLUSIONS AND RECOMMENDATIONS.. 11

Conclusions. 11

 

 


lIST OF TABLES

 

Table I            Summary Table for Non-compliance Recorded

Table 1.1        Key Project Contacts

Table 2.1        Water Quality Monitoring Parameters

Table 2.2        Water Quality Monitoring Equipment

Table 2.3        Locations of Water Quality Monitoring Stations

Table 2.4        Frequency and Parameters of Water Quality Monitoring

 

 

lIST OF FIGUREs

 

Figure 2.1      Location of Monitoring Stations (Lamma Section)

Figure 2.2      Location of Monitoring Stations (Ping Chau Section)

 

 

lIST OF APPENDIces

 

A                     Copy of Calibration Certificates of Monitoring Equipment

B                     Action and Limit Levels for Water Quality Monitoring during Post-Trenching Works

C                     Water Quality Monitoring Results and

Graphical Presentations (DOSM, DOB, TUR & SS)

D                     Quality Control Reports for Laboratory Analysis

E                     Event Action Plan for Water Quality

F                      Water Quality Monitoring Schedule

G                     Construction Phase Mitigation Measures and their Implementation (Gas Pipeline)

H                     Complaint Log

 

 


List of Abbreviation

 

 

DO

Dissolved Oxygen

EIA

Environmental Impact Assessment

EM&A

Environmental Monitoring and Audit

ET

Environmental Team

GPS

Global Positioning System

GRS

Gas Receiving Station

HEC

Hong Kong Electric Co. Ltd

HOKLAS

The Hong Kong Laboratory Accreditation Scheme

LNG

Liquefied Natural Gas

QA/QC

Quality Assurance / Quality Control

SS

Suspended Solids

                       

 

 

 


EXECUTIVE SUMMARY

Introduction

 

1.        This Impact Environmental Monitoring and Audit (EM&A) Report is prepared by Cinotech Consultants Limited (ET-Cinotech) for the post-trenching works for the project “Lamma Project Station Extension – Supply and Installation of Submarine Gas Pipeline” (the Project).  The post-trenching works were commenced on 4th June 2005.

 

2.        This report presents the impact environmental monitoring works performed at the sensitive receivers including Ping Chau, southern Po Toi and Lamma between 4th and 30th June 2005.

Environmental Monitoring Works

 

3.        Environmental monitoring for the Project was performed as stipulated in the Work Procedure and the results were checked and reviewed.

 

Water Quality

 

4.        Post-trenching activities were carried out at Po Toi and south Lamma sensitive areas in the reporting month. Water quality monitoring was performed based on the progress of the post-trenching machine in accordance with the work procedure.  The monitoring was conducted on 17th and 28th June 2005 at Po Toi sensitive area and 22nd and 25th June 2005 at south Lamma sensitive area in the reporting month.   

 

5.        There was no exceedance for all the parameters.  No major pollution sources were identified during the monitoring.  Summary of the non-compliance of the monitoring events is tabulated Table I.

 

Table I      Summary Table for Non-compliance Recorded

Media /

Nature

No. of Exceedances

Action Taken

Results of action taken

Remarks

Action Level

Limit Level

DO

0

0

N.A.

N.A.

-

Turbidity

0

0

SS

0

0

 

6.        In accordance with the work procedure, initial water quality monitoring was also performed for pipeline alignment away from sensitive receivers in the reporting month.  The details of the methodology, locations and results of the initial monitoring were presented in a separate report, “Initial Water Quality Monitoring for Post-Trenching Works Interim Report”.

Complaints and Prosecutions

 

7.        No environmental complaint and prosecution were received during the reporting month.

 

Future Key Issues

 

8.        Post-trenching will be the major activities in the coming month. The anticipated environmental impact will be mainly on water quality.

 


1               INTRODUCTION

Background

1.1        Hong Kong Electric Holdings Ltd. (HEC) intends to develop a 1,800 MW power station in Hong Kong Special Administrative Region (HKSAR) to meet the forecast increase in electricity demand to cope with the social and economical growth of the HKSAR. The proposed power station will be located at reclaimed land in the south of the existing Lamma Power Station at the western edge of Lamma Island, termed Lamma Power Station Extension.

1.2        The proposed Power Station will use natural gas as fuel to generate electricity. The natural gas will be supplied from Guandong Liquefied Natural Gas (GD LNG) Terminal located at Cheng Tou Jiao of Shenzen PRC via a 20 inches diameter gas submarine pipeline. 

1.3        HEC awarded Saipem Asia Sdn. Bhd. (hereafter called “the Contractor) for the design, engineering, supply of materials, fabrication, testing at works, delivery to site, complete erection including pre-trenching, pipe laying, rock dumping, testing and pre-commissioning at site, preservation during the Defects Liability Period of Submarine Gas Pipeline under to Project titled “Lamma Power Station Extension – Supply and Installation of Submarine Gas Pipeline” (hereinafter called “the Project”). Cinotech Consultants Limited was subsequently commissioned by the Contractor as the Environmental Team (ET-Cinotech) to provide environmental consultancy services and to undertake the Environmental Monitoring and Audit (EM&A) works for the Project.

1.4        The Project works include Pre-Trenching works, Pipe-Lay installation, Post-Lay Trenching (Jetting) and Rock Dumping works related to the installation of 92 km of 20 inches diameter Submarine Gas Pipeline between Guandong Liquefied Natural Gas Terminal (GD LNG) and the receiving point at Gas Receiving Station (GRS) at South-West of Lamma Extension on Lamma Island of Hong Kong – SAR.  An Environmental Permit (EP) has been issued for the Lamma Power Station Extension project.  Variations to the EP requirements have been proposed recently for the Project works and the VEP no. EP-071/2000/C was issued on 18th May 2005. 

1.5        In accordance with the requirements of the EM&A Manual, water quality monitoring should be carried out for the jetting operations for the first two weeks of the construction programme. Further monitoring after the initial two weeks should be carried out if unacceptable impacts are revealed.  In addition, monitoring should be carried out at Ping Chau, southern Po Toi and southern Lamma when jetting operation is conducted in the vicinity of these ecological sensitive areas identified in the EIA report. The original water quality monitoring programme stipulated in the EM&A Manual has been reviewed and updated to cater for the proposed variations of the EP requirements.  The updates include a 3-day intensive water quality programme, which supersedes the original two-week programme.  Baseline and impact monitoring will also be undertaken at the said three sensitive zones defined in the EIA report. 

1.6        A Work Procedure outlining the monitoring and audit programme to be undertaken for the post-trenching works was submitted.  The baseline water quality monitoring was conducted at the three sensitive zones prior to the commencement of the post-trenching works.  The post-trenching works were commenced on 4th June 2005.

1.7        In accordance with the work procedure, water quality monitoring should be undertaken at mid-flood and mid-ebb tides when the jetting activities are carried out at the three sensitive areas, Ping Chau, southern Po Toi and south Lamma identified in the EIA report.  Water quality monitoring based on the progress of the post-trenching machine was performed in the reporting month. This report presents the monitoring locations, equipment, period, methodology, results and observations for the water quality measurements in June 2005.

Project Organizations

1.8        Different parties with different levels of involvement in the project organization include:

·       Project Proponent –Hong Kong Electric Holdings Ltd. (HEC)

·       Contractor – Saipem Asia Sdn. Bhd.

·       Environmental Team (ET-Cinotech) – Cinotech Consultants Limited

 

1.9        The responsibilities of respective parties are detailed in Section 3 of the EM&A Requirements Review (Review) and the project organization chart is presented in Figure 3.1 of the Review. The key contacts of the ET- Cinotech are shown in Table 1.1.

Table 1.1     Key Project Contacts

Party

Name

Role

Phone No.

Fax No.

ET-Cinotech

Dr. Priscilla Choy

Project Manager

2151 2089

3107 1388

Ms. Winniss Kong

Coordinator

2151 2068

3107 1388

Mr. Henry Leung

Monitoring Team Leader

2151 2087

3107 1388

 


2               Water Quality Monitoring

Monitoring Requirements

2.1        During the course of the post-trenching works, monitoring should be undertaken at mid-flood and mid-ebb tides, when the post-trenching activities are carried out at the three sensitive areas, Ping Chau, southern Po Toi and Lamma as identified in the EIA report.

2.2        In accordance with the work procedure, initial water quality monitoring was required. The initial water quality monitoring was performed in the reporting month.  The details of the methodology, locations and results of the initial monitoring were presented in a separate report, “Initial Water Quality Monitoring for Post-Trenching Works Interim Report”.

Monitoring Parameters

2.3        The following water quality parameters were included in the monitoring programme.

Table 2.1     Water Quality Monitoring Parameters

Phase

Water Quality Parameters

Construction

·    Salinity (ppt)

·    Turbidity (NTU)

·    Dissolved oxygen (DO) (mg/L and % of saturation)

·    Suspended solids (SS) (mg/L)

 

Monitoring Equipment

2.4        The water samplers used for water quality monitoring were Kahlsico Water-Bottle Model 135DW150.  The samplers with associated equipment complied with the specifications stipulated in the work procedure.

2.5        Table 2.2 summarizes the equipment used in the water quality monitoring program.  All the monitoring equipment complied with the specifications stipulated in the work procedure.  Copies of the calibration certificates of are attached in Appendix A.

Table 2.2     Water Quality Monitoring Equipment

Equipment

Model and Make

Qty.

Water Sampler

Kahlsico Water-Bottle Model 135DW 150

2

Multi-parameter Water Quality System

YSI 6820

2

 

Monitoring Locations

2.6        A total of fourteen water quality monitoring locations were selected at the three sensitive areas.  Table 2.3 describes the locations of these monitoring stations.  The locations of the control and impact monitoring stations are shown in Figures 2.1 and 2.2.

Table 2.3  Locations of Water Quality Monitoring Stations

ID

Location / Corresponding Sensitive Area

Type of Monitoring Station

Co-ordinates

Easting

Northing

L-C1

Lamma Island

Control Station

827183.8

807646.2

L-C2

Control Station

831676.1

802177.5

L-I1

Impact Station

828810.5

806397.2

L-I2

Impact Station

828885.4

803509.1

PT-C1

Po Toi

Control Station

842723.2

803604.7

PT-C2

Control Station

847367.7

801893.2

PT-I1

Impact Station

843897.0

802669.5

PT-I2

Impact Station

843788.9

802085.1

PT-I3

Impact Station

843751.8

801793.7

PC-C1

Ping Chau

Control Station

861173.7

848150.6

PC-C2

Control Station

864446.5

842633.7

PC-I1

Impact Station

862140.0

846255.0

PC-I2

Impact Station

862126.0

845003.0

PC-I3

Impact Station

863196.0

843564.0

Monitoring Frequency and Duration

2.7        Table 2.4 summarizes the monitoring period and frequencies of water quality monitoring.

Table 2.4     Frequency and Parameters of Water Quality Monitoring

Station

Parameters

Frequency

No. of depth

L-C1, L-C2, L-I1, L-I2, PT-C1, PT-C2, PT-I1, PT-I2, PT-I3, PC-C1, PC-C2, PC-I1, PC-I2, PC-I3

SS, turbidity, DO and in-situ parameters*

At mid-ebb and mid-flood tides when the post-trenching activities are carried out at the three sensitive areas shown in Figures 2.1 and 2.2 

3 (1m below water surface, mid-depth and 1m above channel bed.)

Notes:

*   In-situ parameters included temperature, salinity and DO saturation.

 

Monitoring Methodology, Calibration Details and QA/QC Procedures

Instrumentation

2.8        A multi-parameter meter (Model YSI 6820 CE-C-M-Y) was used to measure DO, turbidity, salinity, and temperature.  Digital Global Positioning Systems (DGPS) were used to ensure that the correction locations were arrived prior to measurement and sample collection.

Operating/Analytical Procedures

2.9        At each measurement, two consecutive measurements of in-situ parameters were taken.  The probes were retrieved out of the water after the first measurement and then re-deployed for the second measurement.  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.

2.10    For SS measurement, grab samples were collected.  Water samples of about 1,000 ml were collected and stored in polyethylene bottles.  The sample bottles were packed into an ice-box and delivered to a HOKLAS Laboratory, WELLAB Ltd., for the analysis within 24 hours.

Maintenance and Calibration

2.11    Before each round of monitoring, a zero check in distilled water was performed with the turbidity probe of YSI 6820.  The probe was kept in wet condition and then calibrated with a solution of known NTU.

2.12    Verifications of the DGPS were carried out at a known fixed reference point (survey nail obtained from the Survey and Mapping office of Lands Department).  The position was monitored over a period of 5 minutes.  Deviations of smaller than +/- 5 metres were demonstrated and recorded.

2.13    QA/QC procedures for the suspended solids analyzed in the HOKLAS-accredited laboratory, Wellab Limited are attached in Appendix C.

Results and Observations

2.14    The monitoring results and the graphical presentation are shown in Appendix C.  Note that in Appendix C, the “sea condition” is given as indicative information and does not necessarily adhere to any standard sea state descriptions.  In general, “calm” means small or no waves were observed; “rough” includes white-capped sea or rougher; and “moderate” means all conditions in between “calm” and “rough”.  

2.15    Post-trenching activities were carried out at Po Toi and south Lamma sensitive areas in the reporting month.  Water quality monitoring was conducted based on the progress of the post-trenching machine.  The monitoring was performed on 17th and 28th June 2005 at Po Toi sensitive area and 22nd and 25th June 2005 at south Lamma sensitive area.  

2.16    No exceedance for DO, turbidity and SS concentrations were recorded at the impact monitoring stations at the two sensitive areas.  The monitoring data of the impact monitoring stations were also comparable to that of the control stations.  No major pollution source was observed during the monitoring sessions.


3                ENVIRONMENTAL AUDIT

Review of Environmental Monitoring Procedures

3.1        The monitoring works conducted by the monitoring team were inspected.  The following observations have been recorded for the monitoring works:

·       The monitoring team recorded all observations around the monitoring stations, which might affect the monitoring result.

·       The monitoring team recorded the weather and sea conditions on the monitoring day.

 

Implementation Status of Event Action Plans

3.2        The Event Action Plan for water quality is presented in Appendix E.  No exceedance was recorded in the monitoring event.  No action was required.

Implementation Status of Mitigation Measures

3.3        The implementation status of mitigation measures is summarized in Appendix G.

Summary of Non-compliance of the Environmental Quality Performance Limit

3.4        No non-compliance was recorded during the site audits in the reporting month. 

3.5        In accordance with the work procedure, initial water quality monitoring was performed for pipeline alignment away from sensitive receivers in the reporting month.  The details of the methodology, locations and results of the initial monitoring were presented in a separate report, “Initial Water Quality Monitoring for Post-Trenching Works Interim Report”.

Summary of Complaints and Prosecution

3.6        No environmental complaint and prosecution was received during the reporting month.  The complaint log for the works is provided in Appendix H.


4               FUTURE KEY ISSUES

Key Issues for the Coming Month

4.1        Post-trenching will be the major activities in the coming month and will be carried out at Ping Chau sensitive area. The anticipated environmental impact will be mainly on water quality.

 

Monitoring Schedule for the Next Month

4.2         The tentative environmental monitoring schedule for the next month is shown in Appendix F.

 


5               CONCLUSIONS AND RECOMMENDATIONS

Conclusions

5.1        Environmental monitoring works were performed on 17th and 28th June 2005 at Po Toi sensitive area and 22nd and 25th June 2005 at south Lamma sensitive area in accordance with the work procedure based on the progress of the post-trenching machine.  All monitoring results were checked and reviewed.

5.2        There was no Action/Limit Level exceedance for all the water quality parameters.  No major pollution sources were identified.