Contract No. 00/9281

Lamma Power Station Extension

Baseline Marine Water Quality Monitoring

 

 

Baseline Monitoring Report

(Revision No. 3)

 

 

 

 

 

Prepared for

The Hongkong Electric Company Limited

By

Environmental Management Division

Hong Kong Productivity Council

 

 

 

29th March 2001

 

 

 

 

 

 

 

 

 

 

 

 

 

Contract No. 00/9281

Lamma Power Station Extension

Baseline Marine Water Quality Monitoring

 

 

 

 

 

 

 

 

Baseline Monitoring Report

(Revision No. 3)

 

 

 

 

 

 

 

 

 

 

 

 

Quality Index

Date

Reference No.

Prepared by

Endorsed by

29th March 2001

01016290\1592_029

Daniel Sum

K. L. Tsang

Table of Contents

 

EXECUTIVE SUMMARY

1.

1.1

1.2

INTRODUCTION

Scope of the Report

Structure of the Report

 

2.

2.1

PROJECT INFORMATION

Background

 

3.

3.1

3.2

3.3

3.4

3.5

3.6

MONITORING METHODOLOGY

Monitoring Locations

Monitoring Periods

Monitoring Methodology

Monitoring Equipment

Equipment Calibration

Laboratory Analysis & QA/QC

 

4

4.1

4.2

4.3

BASELINE MONITORING RESULTS

General

Weather and Major Activities at the Site During the Monitoring Period

Marine Water Quality Action & Limit Levels

 

5

CONCLUDING REMARKS

 

 

List of Appendices

 

Appendix A Calibration Records of Water Quality Monitoring Equipment

Appendix B Chain-of-Custody Records

Appendix C Water Quality Monitoring Field Logs

Appendix D Laboratory Analysis Results of Marine Water Samples

Appendix E Baseline Levels of Marine Water Quality at All Stations

Appendix F Calculation of Action and Limit Levels of Marine Water

Appendix G Laboratory QA/QC Results

Appendix H Figure Showing Marine Water Monitoring Locations

Appendix I HOKLAS Certificate of Hong Kong Productivity Council Environmental Management Division Laboratory

Appendix J Graphical Presentation of Marine Water Monitoring Results

Appendix K Schedule of Reclamation Programme

Appendix L Calculation of "Unionized Ammonia

 

  

EXECUTIVE SUMMARY

The Hongkong Electric Company Limited (HEC) is planning to construct an extension of the existing Lamma Power Station to cater for the forecasted increased in electricity demand. In this connection, HEC has appointed the Hong Kong Productivity Council (HKPC) to conduct the baseline water quality monitoring works in the surrounding waters in accordance with the recommendations as stipulated in the Environmental Impact Assessment under the Environmental Impact Assessment Ordinance.

This Report has been prepared to document the baseline marine water monitoring conducted for the construction of the Lamma Power Station Extension project. Monitoring of marine water quality was carried out from 6th November to 1st December 2000, prior to the commencement of construction works. From the analysis of the collected data and field observations, it is concluded that the measured water quality is representative of pre-construction ambient conditions.

 

Monitoring Results

Depth-average Dissolved Oxygen measurement results at sensitive receiver and control monitoring stations are in the range of 5.7 – 8.4 mg/L and 5.1 – 8.3 mg/L respectively. Dissolved Oxygen measurement results of bottom level at sensitive receiver and control monitoring stations are in the range of 5.6 – 8.4 mg/L and 4.2 – 8.3 mg/L respectively.

Depth-average Suspended Solids measurement results at sensitive receiver and control monitoring stations are in the range of 4.8 – 25.4 mg/L and 5.5 – 25.7 mg/L respectively.

Depth-average measurement results of Unionized Ammonia at the sensitive receiver and control monitoring stations are in the range of 0.001 – 0.007 mg/L and 0.001 – 0.008 mg/L respectively.

The depth–average measurement results of Total Inorganic Nitrogen at the sensitive receiver and control monitoring stations are in the range of 0.01 – 0.27 mg/L and 0.03 – 0.28 mg/L respectively.

 

Determination of Action and Limit Levels

Based on the collected data, marine water quality Action and Limit Levels have been established at each monitoring station and are documented in Section 4.3 of this Report.

 

 

1. INTRODUCTION

1.1 Scope of the Report

This is the Baseline Marine Water Quality Monitoring Report for the Lamma Power Station Extension project. This report has been prepared by the Environmental Management Division of Hong Kong Productivity Council (HKPC) for submission to The Hongkong Electric Company Limited (HEC).

1.2 Structure of the Report

The structure of the report is as follows:

Section 1: INTRODUCTION - details the scope and structure of the report.

Section 2: PROJECT INFORMATION - summarizes the background of the project.

Section 3: MONITORING METHODOLOGY – describes the monitoring locations, monitoring period, monitoring equipment to be used for the on-site measurement, laboratory analysis methodology and the associated QA/QC result

Section 4: BASELINE MONITORING RESULTS – presents the monitoring results and the established Action and Limit Levels

Section 5: CONCLUDING REMARKS

2. PROJECT INFORMATION

2.1 Background

The Hongkong Electric Company (HEC) Limited is planning to construct a 1,800 MW gas-fired combined cycle plant as an extension of the existing Lamma Power Station to cater for the forecasted increase in electricity demand. An Environmental Impact Assessment under the EIAO has been conducted which recommended an EM&A programme for the construction activities of Lamma Power Station Extension (Lamma Extension). A baseline water quality monitoring as part of the EM&A programme prior to the construction activities (scheduled to commence in January 2001) was also recommended. In this connection, HEC appointed the Hong Kong Productivity Council (HKPC) to conduct the baseline water quality monitoring works at all the recommended sensitive receiver monitoring and control stations. The baseline water monitoring was commenced in November 2000 and completed in December 2000. The schedule of the reclamation programme is enclosed in Appendix K.

 

3. MONITORING METHODOLOGY

3.1 Monitoring Locations

In order to monitor the potential environmental impact of the project during the construction period, seven stations (SR1 to SR7) were selected to be the sensitive receiver monitoring locations to gauge any potential impact on water quality during the entire construction period. On the other hand, in order to monitor the possible background fluctuation of the study area during the impact monitoring period, another five control monitoring stations (C1 to C5), which were not predicted to be impacted by the construction works for the extension, were also monitored together with the sensitive receiver monitoring stations. These locations are listed in Table 3.1 below, and are also depicted in Appendix H.

Table 3.1: Marine Water Monitoring Locations

Station I.D.

HK Metric Grid

Easting

HK Metric Grid

Northing

Sensitive Receiver Stations

SR1

830224

811528

SR2

829004

810903

SR3

829194

808600

SR4

830119

808650

SR5

830386

807189

SR6

829977

805758

SR7

829566

804545

Control Stations

C1

830542

813492

C2

828608

813492

C3

826776

809978

C4

826776

806464

C5

830440

802186

 

3.2 Monitoring Periods

The monitoring began on 6th November 2000 and continued until 1st December 2000. During this period, baseline marine water quality monitoring data was collected three times per week for four weeks at each monitoring station during mid-ebb and mid-flood tides. The baseline monitoring periods for marine water are summarized in Table 3.2.

Table 3.2: Baseline Monitoring Period

Sampling Dates

Sampling Time

Tide Conditions

Weather

6/11/2000 (Monday)

6:45 a.m. - 9:34 a.m.

2:15 p.m. - 5:17 p.m.

Ebb

Flood

Cloudy

8/11/2000 (Wednesday)

8:00 a.m. - 11:10 a.m.

2:53 p.m. - 6:01 p.m.

Ebb

Flood

Cloudy

10/11/2000 (Friday)

9:29 a.m. - 12:44 p.m.

3:30 p.m. - 6:31 p.m.

Ebb

Flood

Clear

13/11/2000 (Monday)

11:27 a.m. - 2:56 p.m.

6:48 a.m. - 9:56 a.m.

Ebb

Flood

Clear

15/11/2000 (Wednesday)

1:05 p.m. - 4:07 p.m.

7:42 a.m. - 10:43 a.m.

Ebb

Flood

Cloudy

17/11/2000 (Friday)

3:04p.m. - 5:58 p.m.

9:54 a.m. - 1:09 p.m.

Ebb

Flood

Overcast

21/11/2000 (Tuesday)

7:23 a.m. - 10:34 a.m.

1:52 p.m. - 5:01 p.m.

Ebb

Flood

Windy

23/11/2000 (Thursday)

9:17 a.m. - 12:40 p.m.

3:00 p.m. - 5:51 p.m.

Ebb

Flood

Clear

25/11/2000 (Saturday)

10:35 a.m. -1:38 p.m.

4:03 p.m. - 6:50 p.m.

Ebb

Flood

Clear

27/11/2000 (Monday)

11:38 a.m. - 2:39 p.m.

6:23 a.m. - 9:11 a.m.

Ebb

Flood

Overcast

29/11/2000 (Wednesday)

12:43 p.m. - 4:07 p.m.

7:51 a.m. - 10:54 a.m.

Ebb

Flood

Clear

1/12/2000 (Friday)

1:58 p.m. - 4:50 p.m.

9:19 a.m. - 12:26 p.m.

Ebb

Flood

Clear

  

 3.3 Monitoring Methodology

The monitoring stations were accessed using survey boat to within 3 m by the guide of a Differential Global Positioning System (DGPS). The depth of the monitoring location was measured using depth meter in order to determine the sampling depths. Afterwards, the probes of the in-situ measurement equipment were lowered to the predetermined depths (1 m below water surface, mid-depth and 1 m above seabed) and the measurements were carried out accordingly. In case water depth was less than 6 m, only measurement at 1 m below water surface and 1 m above seabed were carried out. The in-situ measurements at predetermined depths were carried out in duplicate. In case the difference in the duplicate in-situ measurement results was larger than 25%, the third set of in-situ measurement would be carried out for result confirmation purpose. Water sampler was lowered into the water to the required depths of sampling. Upon reaching the pre-determined depth, a messenger to activate the sampler was then released to travel down the wire. The water sample was sealed within the sampler before retrieving. At each station, water samples at three depths (1 m below water surface, mid-depth and 1 m above seabed) were collected accordingly. In case water depth was less than 6 m, only water samples at 1 m below water surface and 1 m above seabed were collected. Water samples for physical and chemical analysis were stored into a pre-labelled high-density polyethylene (HDPE) bottle, kept at 4oC and sent to the Hong Kong Productivity Council Environmental Management Division Laboratory upon the completion of each round of sampling (a copy of the certificate of the HOKLAS accreditation is shown in Appendix I). In addition, field information such as general meteorological conditions and notes regarding any significant activities at each monitoring location were also recorded.

  

3.4 Monitoring Equipment

The equipment deployed for the on-site measurement of marine water quality is summarized in Table 3.3.

Table 3.3: Equipment Used for Marine Water Monitoring

Equipment

Detection Limit

Wildco Water Sampler

Not Applicable

Eagle Fish ID 128 Depth Meter

Not Applicable

YSI 6820 Water Quality Monitor

Temperature: -5 to 50 oC; +/- 0.15 oC

Salinity: 0 to 70 ppt (mg/L); +/- 0.1 ppt (mg/L)

Dissolved Oxygen: 0 to 20.0 mg/L +/- 0.02 mg/L

0 to 200% +/- 0.5 %

Turbidity: 0 to 100 and 100 to 1000 NTU; +/- 5% of the range

pH: 0 to 14 units +/- 0.2 units

YSI 58 DO Meter

Temperature: -5 to 45 oC; +/- 0.3 oC

Dissolved Oxygen: 0 to 20.0 mg/L +/- 0.002 mg/L

0 to 200% +/- 0.5 %

HACH 2100P Turbidity Meter

Turbidity: 0 to 1000 NTU; +/- 2% of the range

YSI 30 Salinity Meter

Salinity: 0 to 80 ppt; +/- 0.1 ppt

Orion 250A

pH: 0 to 14 units +/- 0.02 units

Trimble NT200 GPS

Accuracy better than 3 m

Note: The measurement ranges and the accuracy of the said monitoring equipment fulfill the requirements as stipulated in the EM&A Manual dated October 2000

3.5 Equipment Calibration

The equipment deployed for on-site measurement of marine water quality was calibrated before use. The methodologies for the calibration are referred to the instruction manual provided by the manufacturers respectively. The calibration records are shown in Appendix A. The results of calibration indicated that the equipment deployed for the on-site measurement of marine water during the sampling period were calibrated properly and operated with the required accuracy.

 

 

3.6 Laboratory Analysis & QA/QC

The collected marine water samples were analyzed for Suspended Solids, Total Inorganic Nitrogen and Unionized Ammonia with methodologies as summarized in Table 3.4.

Table 3.4: Laboratory Analysis Methodologies of Marine Water Samples

Parameter

Method

Limit of Reporting (mg/L)

Suspended Solids

APHA 17 ed 2540 D

1.0

Total Inorganic Nitrogen

APHA 18 ed 4500 NO2 B & NO3 E + APHA 17ed 4500-NH3B, E

0.01

Ammoniacal Nitrogen

(Un-ionized Ammonia)

APHA 17 ed 4500-NH3 G

0.01

(Limit of Reporting for Ammoniacal Nitrogen) x degree of ionization

Note: The determination of unionized ammonia was based on the articles entitled “Aqueous Ammonia Equilibrium Calculation: Effect of pH and Temperature” and “Ionization of Ammonia in Seawater: Effects of Temperature, pH and Salinity” which was accepted by EPD.

In order to ensure that the laboratory analysis works were carried out properly, stringent QA/QC procedures (which include the sample preparation as well as the subsequent instrumentation analysis) were followed. According to the requirements as stipulated in the EM&A Manual, QA/QC requirements for laboratory testing include: 1) "Blind" duplicate samples analysis of 10% collected marine water samples; and 2) in-house QA/QC procedures of the testing laboratory (this includes the use of blank, batch duplicates, quality control samples and matrix spike recovery test).

Blind Duplicate

In order to check on the precision of the measurement results obtained from the laboratory analysis, “blind” duplicates samples of 10% of the collected marine water samples were analysed alongside the normal samples. The sample codes for the “blind” duplicates were determined by the sampling team and they are not identifiable by the laboratory. The details of the “blind” duplicate samples are summarized in Appendix G.

 

In accordance to the QA/QC procedures of Environmental Management Laboratory, QA/QC procedures shall be conducted for 5% of samples. A total of 864 sets of samples were received during the marine monitoring at both ebb and flood tides. Therefore 5% laboratory blanks, batch duplicates, quality control samples and recovery tests (43 sets) for each parameter were conducted. The acceptance criteria are outlined in each type of Quality Control data.

Blank:

A laboratory blank is an analyte free matrix to which all reagents are added in the same volumes or proportions as used in the standard sample preparation to monitor contamination introduced in laboratory. The acceptance criterion for laboratory blank in EMD Laboratory stipulated in EMD Quality Manual is less than the detection limit. All the laboratory blank values and acceptance criterion of the following testing parameters are summarized in Table 3 of Appendix G.

 

Batch Duplicate:

Batch duplicate is an intra-laboratory split sample randomly selected from the sample batch to monitor the method precision in a given matrix. The acceptance limit of duplicate values of the following testing parameters and their duplicate results are summarized in Table 2 Appendix G.

 

Quality Control Sample:

The quality control sample is the analysis of material with a known concentration of contaminants to determine the accuracy of results in a given matrix. The quality control samples are not applicable to all testing parameters due to the constraints of the testing parameters. The quality control samples results for the following testing parameters are shown in Table 4 of Appendix G.

 

Quality control sample testing is not applicable to the testing of Suspended Solids.

 

Matrix Spike:

Matrix spike is an intra-laboratory split of a sample digested spiked with target known concentration analyte to determine method bias in a given matrix. The matrix spike is applicable to the following tests:

 

Matrix spike testing is not applicable to testing of Suspended Solids. The matrix spike samples results are shown in Table 5 of Appendix G.

The QA/QC results as shown in Appendix G indicated that the laboratory analysis works of the collected marine water samples were properly carried out and the measurement results obtained were valid in accordance with the Hong Kong Laboratory Accreditation Scheme (HOKLAS) requirements. On the other hand, the “blind” duplicate measurement results indicated that the precision of the measurement of Suspended Solids, Total Inorganic Nitrogen and Unionized Ammonia are in compliance with the HOKLAS requirements.

 

4 BASELINE MONITORING RESULTS

4.1 General

The on-site measurement results of marine water at all monitoring locations are detailed in Appendix C. Laboratory analysis results are presented in Appendix D.

The baseline data of monitoring parameters at each monitoring location in terms of average and ranges are summarized in Table 4.1 and Table 4.2. On the other hand, the results of Dissolved Oxygen, Turbidity, Suspended Solids, Unionized Ammonia and Total Inorganic Nitrogen (which are classified as target parameters of the Water Quality Objectives) are presented graphically in Appendix J. The method of the determination of "Unionized Ammonia" is shown in Appendix L.

4.2 Weather and Major Activities at the Site During the Monitoring Period

Based on the observation made by the sampling team during the course of baseline monitoring, the majority of weather conditions during the monitoring period at all monitoring locations were cloudy. Generally speaking, it is considered that the weather conditions during the monitoring period were suitable for baseline monitoring.

On the other hand, in order to justify whether the activities at the vicinity of the study area is suitable for the baseline marine water sampling, on-site observation by the sampling team was carried out at each monitoring locations during each sampling trips. Based on the on-site observation made by the sampling team during the baseline monitoring period, no pertinent activities were carried out at the vicinity of the study area that would affect the monitoring results. On the other hand, based on the information provided by HEC, no abnormal operation was recorded from the operation of the power plants at the Lamma Power Station during the period of the baseline marine water monitoring. Account for the above, it is considered that the conditions of the study area during the monitoring periods were appropriate for baseline monitoring

 

Table 4.1: Summary of Field Measurement Data

Station

DO-Top (mg/L)

DO-Mid (mg/L)

DO-Bot (mg/L)

DO-Avg (mg/L)

DO%-Top

DO%-Mid

DO%-Bot

pH-Top

pH-Mid

pH-Bot

pH-Avg

SR1

Average

6.67

6.69

6.65

6.67

90.3

90.0

89.8

8.18

8.19

8.20

8.19

Minimum

5.94

5.86

5.85

5.93

82.5

80.6

80.6

7.95

7.99

7.99

7.98

Maximum

8.25

8.63

8.09

8.18

96.9

96.4

96.9

8.51

8.48

8.50

8.47

SR2

Average

6.69

6.68

6.67

6.68

90.6

90.4

90.3

8.18

8.20

8.22

8.20

Minimum

5.93

5.87

5.94

5.97

81.5

81.9

82.2

7.91

7.99

8.00

7.97

Maximum

8.35

8.28

8.17

8.26

98.5

98.5

98.2

8.49

8.46

8.55

8.46

SR3

Average

6.90

6.89

6.89

6.89

93.4

93.2

93.0

8.20

8.22

8.22

8.21

Minimum

5.96

5.98

6.00

5.99

85.3

85.0

84.9

7.93

7.99

8.00

7.99

Maximum

8.42

8.42

8.38

8.40

99.4

99.2

99.5

8.48

8.43

8.43

8.44

SR4

Average

6.88

6.79

6.84

6.89

93.1

92.8

92.5

8.23

8.22

8.24

8.23

Minimum

6.01

5.96

5.93

5.99

82.4

81.9

81.5

7.92

7.98

7.99

7.97

Maximum

8.43

8.28

8.41

8.42

99.1

99.0

98.9

8.43

8.42

8.42

8.42

SR5

Average

6.88

6.73

6.84

6.86

93.3

92.1

92.5

8.22

8.22

8.24

8.23

Minimum

6.02

5.90

5.86

5.96

82.5

81.1

80.5

7.89

7.98

8.00

7.97

Maximum

8.38

7.64

8.35

8.36

99.9

99.4

98.8

8.58

8.46

8.48

8.48

SR6

Average

6.86

6.84

6.79

6.83

93.0

92.7

91.9

8.21

8.22

8.23

8.22

Minimum

5.78

5.70

5.68

5.74

79.4

78.6

78.4

7.95

7.99

8.06

8.01

Maximum

8.35

8.37

8.25

8.32

99.0

99.4

99.0

8.44

8.45

8.45

8.44

SR7

Average

6.87

6.83

6.80

6.83

93.1

92.5

92.1

8.22

8.23

8.23

8.23

Minimum

5.68

5.69

5.64

5.69

78.4

78.6

78.0

7.96

8.04

8.06

8.04

Maximum

8.33

8.34

8.32

8.33

98.7

98.9

98.9

8.43

8.50

8.45

8.45

C1

Average

6.66

6.61

6.62

6.63

90.0

89.4

89.5

8.18

8.19

8.20

8.19

Minimum

5.88

5.74

5.42

5.80

81.2

79.3

77.6

7.89

7.88

7.98

7.92

Maximum

8.12

8.21

8.26

8.19

97.0

96.7

97.4

8.47

8.45

8.44

8.45

C2

Average

6.67

6.61

6.60

6.63

90.2

89.4

86.4

8.16

8.17

8.20

8.18

Minimum

5.81

5.81

5.80

5.84

81.3

80.3

10.6

7.93

7.94

7.96

7.95

Maximum

8.18

8.08

8.08

8.11

97.0

96.9

96.8

8.46

8.45

8.94

8.53

C3

Average

6.74

6.72

6.69

6.72

91.5

91.1

90.5

8.18

8.18

8.19

8.18

Minimum

5.28

5.33

5.30

5.32

72.7

73.4

73.0

7.96

7.97

7.99

7.98

Maximum

8.04

8.02

8.04

8.01

97.8

98.4

97.7

8.70

8.39

8.41

8.39

C4

Average

6.87

6.80

6.74

6.80

93.0

91.7

90.8

8.23

8.23

8.23

8.23

Minimum

6.07

4.65

4.24

5.12

83.7

66.7

60.4

8.00

8.04

8.00

8.03

Maximum

8.12

8.18

8.26

8.18

99.2

99.3

99.6

8.55

8.48

8.47

8.49

C5

Average

6.90

6.83

6.81

6.85

93.3

92.2

92.0

8.25

8.24

8.25

8.25

Minimum

5.61

5.53

5.45

5.55

77.0

76.1

75.0

8.01

8.06

7.93

8.04

Maximum

8.38

8.35

8.34

8.35

100.0

99.1

99.1

8.56

8.51

8.49

8.51

Table 4.1: Summary of Field Measurement Data (Cont'd)

Station

Temp-Top (oC)

Temp-Mid (oC)

Temp-Bot (oC)

Sal-Top (ppt)

Sal-Mid (ppt)

Sal-Bot (ppt)

Turb-Top (NTU)

Turb-Mid (NTU)

Turb-Bot (NTU)

Turb-Avg (NTU)

SR1

Average

22.97

23.07

23.01

31.4

31.5

31.5

8.5

9.4

12.0

10.0

Minimum

21.21

22.01

22.01

30.8

30.8

30.7

4.9

5.5

4.9

5.4

Maximum

24.46

24.49

24.48

32.5

32.0

32.1

19.1

17.9

43.3

24.1

SR2

Average

23.05

23.09

23.04

31.4

31.4

31.5

10.4

8.8

9.4

9.5

Minimum

21.33

21.93

21.95

30.8

30.9

31.0

4.2

4.5

4.4

4.8

Maximum

24.74

24.48

24.53

32.6

32.3

32.0

42.9

16.9

16.5

19.7

SR3

Average

23.04

22.98

22.92

31.5

31.5

31.6

9.1

9.9

10.8

9.9

Minimum

21.58

21.93

21.84

30.9

30.7

31.1

3.6

3.6

4.4

3.9

Maximum

24.61

24.52

24.42

32.5

32.0

32.2

24.9

16.9

18.6

18.7

SR4

Average

22.90

22.83

22.81

31.4

31.5

31.6

7.8

9.2

10.4

9.1

Minimum

21.74

21.84

21.79

30.8

31.2

31.3

3.6

3.5

5.7

4.7

Maximum

24.61

24.33

24.29

32.6

32.0

32.3

12.3

13.4

20.3

13.7

SR5

Average

22.88

23.05

22.83

31.4

31.5

31.5

8.9

9.7

10.2

9.6

Minimum

21.56

21.79

21.74

30.7

30.7

30.8

4.7

4.1

3.9

4.3

Maximum

24.34

31.77

24.26

32.4

31.9

32.0

18.9

21.4

28.5

18.4

SR6

Average

22.92

22.86

22.88

31.5

31.5

31.6

10.3

10.0

11.6

10.6

Minimum

21.55

21.84

21.85

30.8

30.9

30.7

3.9

3.9

4.7

4.4

Maximum

24.46

24.50

24.28

32.3

32.1

32.2

21.5

17.6

27.8

18.1

SR7

Average

22.91

22.86

22.85

31.5

31.6

31.6

9.2

10.1

12.1

10.5

Minimum

21.73

21.88

21.85

30.7

31.1

30.8

2.4

3.0

4.1

3.4

Maximum

24.32

24.25

24.22

32.2

32.1

32.2

23.2

22.1

23.6

22.7

C1

Average

22.98

23.05

23.00

31.4

31.6

31.5

7.7

9.3

14.3

10.4

Minimum

21.31

22.09

22.06

30.8

31.0

30.7

4.1

4.2

5.8

4.8

Maximum

24.48

24.51

24.46

32.4

32.1

32.3

17.9

25.5

41.4

28.1

C2

Average

23.04

23.08

23.06

31.4

31.5

31.6

11.2

12.5

14.8

12.8

Minimum

21.83

21.85

22.04

30.9

30.8

30.8

4.5

5.4

6.0

5.8

Maximum

24.43

24.52

24.51

32.2

31.9

32.0

36.7

51.5

68.4

52.1

C3

Average

23.16

23.06

23.03

31.4

31.5

31.6

9.3

9.9

11.1

10.1

Minimum

22.07

22.02

21.98

30.8

31.0

31.1

3.6

4.4

5.4

4.7

Maximum

24.78

24.62

24.52

31.9

31.8

32.2

14.9

14.7

18.2

15.2

C4

Average

23.02

22.91

22.83

31.4

31.5

31.6

8.9

8.9

12.9

10.2

Minimum

21.58

21.90

21.79

31.0

31.0

31.0

3.7

4.4

5.4

5.5

Maximum

25.15

24.66

24.43

32.4

31.9

32.1

16.4

15.7

29.8

15.7

C5

Average

22.89

22.89

22.85

31.4

31.7

31.6

6.6

6.9

10.7

8.1

Minimum

21.67

21.80

21.83

30.8

31.1

31.0

2.1

2.9

3.9

3.6

Maximum

24.42

24.80

24.30

32.4

32.1

32.1

18.4

17.4

19.3

17.5

 

 

Table 4.2: Summary of Laboratory Analysis

Station

SS (mg/L)

NH3-N (mg/L)

(NO2, NO3+NH3)-N(mg/L)

SR1

Average

10.9

0.002

0.12

Minimum

6.7

0.001

0.05

Maximum

19.4

0.007

0.27

SR2

Average

10.8

0.002

0.12

Minimum

6.7

0.001

0.06

Maximum

15.5

0.005

0.26

SR3

Average

10.9

0.001

0.09

Minimum

7.2

0.001

0.06

Maximum

17.9

0.001

0.13

SR4

Average

11.4

0.001

0.08

Minimum

4.8

0.001

0.04

Maximum

19.5

0.003

0.12

SR5

Average

11.6

0.001

0.08

Minimum

5.1

0.001

0.04

Maximum

18.6

0.002

0.11

SR6

Average

11.7

0.001

0.08

Minimum

5.6

0.001

0.03

Maximum

25.4

0.001

0.11

SR7

Average

11.9

0.002

0.09

Minimum

6.0

0.001

0.05

Maximum

19.4

0.003

0.13

C1

Average

12.5

0.002

0.12

Minimum

7.4

0.001

0.06

Maximum

25.7

0.005

0.26

C2

Average

15.4

0.003

0.15

Minimum

6.6

0.001

0.06

Maximum

36.5

0.008

0.28

C3

Average

13.0

0.002

0.11

Minimum

5.5

0.001

0.07

Maximum

19.6

0.007

0.16

C4

Average

11.5

0.001

0.08

Minimum

6.7

0.001

0.04

Maximum

20.0

0.002

0.12

C5

Average

10.0

0.001

0.08

Minimum

6.8

0.001

0.03

Maximum

14.1

0.001

0.13

Note:

The results of Suspended Solids, Unionized Ammonia and Total Inorganic Nitrogen are presented in depth-average.

4.3 Marine Water Quality Action & Limit Levels

Exceedance of Action Level during the impact monitoring period would indicate that environmental quality is deteriorating. Exceedance of Limit Level during the impact monitoring period would indicate that environmental quality has become unacceptable. An Event Action Plan for responding to these exceedances is documented in the EM&A Manual. According to the EM&A Manual, marine water quality Action and Limit Levels are to be established from baseline levels. Subsequent impact monitoring results will be compared against the Action and Limit Levels. Table 4.4 summarizes the methods of determining the Action Levels and Limit Levels.

Table 4.4: Action and Limit (A/L) Levels for Marine Water Quality

Parameter

Action Level

Limit Level

Dissolved Oxygen in mg/L (Surface, Middle and Bottom)

Surface and Middle: 5th percentile of baseline data of surface and middle layer

Bottom: 5th percentile of baseline data for bottom layer

Surface and Middle: For non-FCZ stations, the Limit Level shall be 4 mg/L, whereas for FCZ stations, the Limit Level shall be 5 mg/L or 1%-le of the baseline data

Bottom: 2 mg/L or 1st percentile of baseline data

Suspended Solid in mg/L (depth-averaged)

95th percentile of baseline or 120% upstream control station’s SS at the same tide of the same day. No Action Level is applied to SR3.

99th percentile of baseline, or 130% of upstream control station’s SS at the same tide of the same day. For SR3, the Limit Level is 100 mg/L

Turbidity in NTU (depth-averaged)

95th percentile of baseline data or 120% of upstream control station’s Turbidity at the same tide of the same day

99th percentile of baseline data or 130% of upstream control station’s Turbidity at the same tide of the same day

Un-ionized Ammonia in mg/L (depth- averaged)

95th percentile of baseline data

99th percentile of baseline data or 0.021 mg/L for unionized ammoniacal nitrogen, whichever is greater

Total Inorganic Nitrogen in mg/L (depth-averaged)

95th percentile of baseline data

99th percentile of baseline data or 0.1 mg/L, whichever is greater (Note: as SR1 and C1 are located within the Western Buffer rather than the Southern Waters Control Zone, the limit levels are 99%-ile of the baseline data or 0.4 mg/L whichever is greater)

Notes:

By reviewing the baseline monitoring results, no significant difference in the baseline monitoring results obtained during ebb tides and flood tides was found. Account for the above, it is considered that the use of one set of Action/Limit Levels for both ebb tides and flood tides is already appropriate for the EM&A programme.

With the above methodology, the Actions and Limit Levels have been calculated in compliance with the Environmental Monitoring and Audit Manual and are shown in Table 4.5 to Table 4.9 below:

 

Table 4.5: Field Measurement of Dissolved Oxygen (mg/L)

(a) Surface and Middle

 

SR1

SR2

SR4

SR5

SR6

SR7

Action Level (5%-ile)

6.0

6.0

6.1

6.0

6.0

6.0

1%-ile

6.0

6.0

6.0

6.0

5.8

5.7

Limit Level

4.0

Note:

1. All impact monitoring stations were considered to be non-FCZ stations

2. Since the calculated 1%-ile results are larger than 4.0 mg/L, therefore the Limit Levels are proposed to be 4.0 mg/L according to the EM&A Manual

(b ) Bottom

 

SR1

SR2

SR4

SR5

SR6

SR7

Action Level (5%-ile)

5.9

6.0

6.1

6.1

6.1

6.1

1%-ile

5.9

5.9

5.9

5.9

5.7

5.7

Limit Level

2.0

Note:

1 Since the calculated 1%-ile results are larger than 2.0 mg/L, therefore the Limit Levels are proposed to be 2.0 mg/L according to the EM&A Manual

Table 4.6: Turbidity (NTU)

(depth-average)

 

SR1

SR2

SR4

SR5

SR6

SR7

Action Level (95%-ile)

17.9

16.3

13.2

17.5

17.2

17.3

Limit Level (99%-ile)

22.8

19.0

13.6

18.3

17.9

21.5

Note:

1. The Action Levels can be 95%-ile of baseline data as mentioned above or 120% of upstream control station at the same tide of the same day according to the EM&A Manual

2. The Limit Levels can be 99%-ile of baseline data as mentioned above or 130% of upstream control station at the same tide of the same day according to the EM&A Manual

     

 

Table 4.7: Suspended Solids (mg/L)

(depth-average)

 

SR1

SR2

SR3

SR4

SR5

SR6

SR7

95%-ile

16.8

15.3

13.8

17.6

17.5

16.9

17.5

Action Level

16.8

15.3

--

17.6

17.5

16.9

17.5

99%-ile

18.9

15.5

17.0

19.1

18.4

23.5

19.0

Limit Level

18.9

15.5

100.0

19.1

18.4

23.5

19.0

Note:

1. No Action Level is applied for SR3 according to the EM&A Manual

2. Limit Level of SR3 is 100 mg/L according to the EM&A Manual

3. The Action Levels can be 95%-ile of baseline data as mentioned above or 120% of upstream control station at the same tide of the same day according to the EM&A Manual

4. The Limit Levels can be 99%-ile of baseline data as mentioned above or 130% of upstream control station at the same tide of the same day according to the EM&A Manual

     

Table 4.8: Unionized Ammonia (mg/L)

(depth-average)

 

SR1

SR2

SR4

SR5

SR6

SR7

Action Level (95%-ile)

0.006

0.005

0.003

0.001

0.001

0.001

99%-ile

0.007

0.005

0.003

0.002

0.001

0.003

Limit Level

0.021

0.021

0.021

0.021

0.021

0.021

Note:

1. Since the calculated 99%-ile results are smaller than 0.021 mg/L, therefore the Limit Levels are proposed to be 0.021 mg/L according to the EM&A Manual.

     

Table 4.9: Total Inorganic Nitrogen (mg/L)

(depth-average)

 

SR1

SR2

SR4

SR5

SR6

SR7

Action Level (95%-ile)

0.25

0.23

0.11

0.11

0.11

0.12

99%-ile

0.27

0.25

0.12

0.11

0.11

0.13

Limit Level

0.4

0.25

0.12

0.11

0.11

0.13

Note:

1. Since the calculated 99%-ile results for SR2 to SR7 are larger than 0.1 mg/L, therefore the Limit Levels are proposed to be calculated 99%-ile for SR2 to SR7 according to the EM&A Manual.

2. Since the calculated 99%-ile result for SR1 is smaller than 0.4 mg/L, therefore the Limit Level for SR1 is proposed to be 0.4 mg/L according to the EM&A Manual.

5. CONCLUDING REMARKS

Marine water quality baseline monitoring for the Project in November and December 2000 have been completed. From analysis of the collected data and field observations, it can be concluded that the measured marine quality are representative of pre-construction ambient conditions.

Appendix A

Calibration Records of Water Quality Monitoring Equipment

Appendix B

Chain-of-Custody Records

Appendix C

Water Quality Monitoring Field Logs

Appendix D

Laboratory Analysis Results of Marine Water Samples

Appendix E

Baseline Levels of Marine Water Quality at All Stations

Appendix F

Calculation of Action and Limit Levels of Marine Water

Appendix G

Laboratory QA/QC Results

 Appendix H

Figure Showing Marine Water Monitoring Locations

 Appendix I

HOKLAS Certificate of Hong Kong Productivity Council Environmental Management Division Laboratory

 Appendix J

Graphical Presentation of Marine Water Monitoring Results

Appendix K

Schedule of the Reclamation Programme

 Appendix L

Calculation of "Unionized Ammonia"