Contents

Executive Summary                                                             

1                      Introduction                                                                          

1.1                   Background                                                                           

1.2                   Purpose of this Report                                                    

1.3                   Structure of the Report                                                

2                      Water Quality Monitoring                                              

2.1                   Monitoring Location                                                          

2.2                   Sampling and Testing Methodology                          

2.3                   Baseline Monitoring Results                                        

2.4                   Action and Limit Levels                                                     

3                      conclusion                                                                             

 

ANNEXES

Annex A  

Baseline Water Quality Monitoring Schedule for Zone B

Annex B  

Calibration Reports of Multi-parameter Sensor

Annex C  

QA/ QC Results for Suspended Solids Testing

Annex D  

Baseline Water Quality Monitoring Results for Zone B

 

EXECUTIVE SUMMARY

Baseline Water Quality Monitoring

Baseline water quality monitoring has been conducted between 17 September 2012 and 21 September 2012 at 12 designated monitoring stations (including 8 Sensitive Receiver Stations, 3 Gradient Stations and 1 Control Station) established for the Project.  In situ water quality measurements and water samples were taken at the monitoring stations on three occasions (days), at three depths (surface, middle and bottom) where practical.  The intervals between two sets of monitoring were not less than 36 hours.  The water quality sampling was undertaken within a 4 hour window of 2 hour before and 2 hour after mid flood and mid-ebb tides.  The tidal range selected for the baseline monitoring was at least 0.5 m for both flood and ebb tides as far as practicable. 

No major activities influencing water quality were observed in the vicinity of the Project’s marine works area during the baseline monitoring.  Water quality monitoring results are, therefore, considered to be representative for the baseline conditions of the areas where marine works will be undertaken for the Project.

In accordance with the EM&A Manual, the baseline monitoring results were used to determine the Action and Limit Levels for Dissolved Oxygen (DO), Suspended Solids (SS) and Turbidity for the impact water quality monitoring which will be conducted during marine works of the Project.  The Action and Limit Levels are summarized in Table 1 below.


Table 1           Action and Limit Levels for Water Quality

Parameter

Action Level

Limit Level

SS in mgL-1

(Depth-averaged) (a) (c)

95%-ile of baseline data

(4.09 mg L-1), or

99%-ile of baseline data

(4.60 mg L-1) , and

20% exceedance of value at any impact station compared with corresponding data from control station

30% exceedance of value at any impact station compared with corresponding data from  control station

DO in mgL-1 (b)

Surface and Middle(d)

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

(4.72 mg L-1)

Surface and Middle(d)

5mg/L or 1%-ile of baseline for surface and middle layer

(4.57 mg L-1)

Bottom

5%-ile of baseline data for bottom layers

(4.52 mg L-1)

Bottom

2mg/L or 1%-ile of baseline data for bottom layer

(4.44 mg L-1)

Turbidity in NTU (Depth-averaged) (a) (c)

95%-ile of baseline data

(3.01 NTU), or

99%-ile of baseline data

(3.13 NTU), and

20% exceedance of value at any impact station compared with corresponding data from control station

30% exceedance of value at any impact station compared with corresponding data from  control station

Notes:

a.      “Depth-averaged” is calculated by taking the arithmetic means of reading of all sampled depths.

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

c.      For SS and turbidity, non-compliance of the water quality limits occurs when monitoring result is higher than the limits.

d.      The Action and Limit Level for DO for surface and middle layer were calculated from the combined pool of baseline surface layer data and baseline middle layer data.

 

1                                            Introduction

1.1                                      Background

NTT Com Asia (NTTCA) proposes to install a telecommunication cable (Asia Submarine-cable Express (ASE) cable) of approximately 7,200 km in length, connecting Japan and Singapore with branches to the Philippines, Hong Kong SAR (HKSAR) and Malaysia.  NTTCA is responsible for securing the approval to land the ASE cable in Tseung Kwan O, Hong Kong SAR (HKSAR).  The proposed landing site will be at a new Beach Manhole (BMH) and ultimately connect with a Data Centre in Tseung Kwan O (TKO) Industrial Estate which is scheduled for completion in 2012.  It should be noted that Tseung Kwan O is currently the landing site for a number of submarine cables.  From Tseung Kwan O, the cable will extend eastward approaching the Tathong Channel.  Near to Cape Collinson, the cable is approximately parallel to the Tathong Channel until north of Waglan Island where the cable travels eastward to the boundary of HKSAR waters where it enters the South China Sea.  The total length of cable in Hong Kong SAR waters is approximately 33.5 km.  A map of the proposed cable route is presented in Figure 1.1.

A Project Profile (PP-452/2011) which includes an assessment of the potential environmental impacts associated with the installation of the submarine telecommunications cable system was prepared and submitted to the Environmental Protection Department (EPD) under section 5.(1)(b) and 5.(11) of the Environmental Impact Assessment Ordinance (EIAO) for the application for Permission to apply directly for Environmental Permit (EP).  The Environmental Protection Department, subsequently issued an Environmental Permit (EP- 433/2011). 

Pursuant to Condition 2.4 of the EP, an environmental monitoring and audit (EM&A) programme as set out in the Environmental Monitoring and Audit Manual (M&A Manual) is required to be implemented.  In accordance with the EM&A Manual, baseline monitoring of marine water quality should be undertaken for the Project.  This Water Quality Baseline Monitoring Report (“the Report”) is prepared by ERM-Hong Kong, Limited (ERM) on behalf of NTT Com Asia (NTTCA) to present the methodology and findings of the baseline marine water quality monitoring for the Project. 

Given that the water sampling stations in Zone B are situated quite far away from those in Zones A and C, and the commencement dates of construction in each zone are also different, it is recommended to present the baseline data in separate reports (i.e. Part A for Zone A, Part B for Zone B and Part C for Zone C) and the corresponding Action and Limit Levels will be derived from the baseline data for each zone.

1.2                                      Purpose of this Report

The purpose of this Baseline Water Quality Monitoring Report (Part B) is to determine the baseline marine water quality at the designated monitoring locations around the Project works area in Zone B prior to the commencement of the cable laying works of the Project.  Such baseline conditions will be used as the basis for assessing water quality impacts, if any, and for compliance monitoring during the construction of the Project. 

Under the requirement of Condition 2.4 of the EP, the baseline monitoring report on water quality shall be prepared and submitted to the DEP no later than two weeks before the commencement of construction works of the Project.

1.3                                      Structure of the Report

The remainder of the report is structured as follows:

Section 1: Introduction

Provide details of the background, purpose and structure of the report.

Section 2: Water Quality Monitoring

Summarize the water quality monitoring locations and frequency, monitoring methodology and baseline monitoring results, and establishes the Action and Limit Levels in accordance with the EM&A Manual.

Section 3: Conclusion

Conclude the representativeness of the baseline monitoring results and observations for the Project.

2                                            Water Quality Monitoring

2.1                                      Monitoring Location

Baseline water quality monitoring in Zone B was conducted prior to the commencement of cable laying works at the monitoring stations listed in
Table
2.1 and shown in Figure 2.1.

·      B1 is an Impact Station to monitor the impacts of cable installation works on the Big Wave Bay Beach;

·      B2 is an Impact Station to monitor the impacts of cable installation works on the Rocky Bay Beach;

·      B3 is an Impact Station to monitor the impacts of cable installation works on the Shek O Beach;

·      E1 is an Impact Station to monitor impacts of cable installation works on Cape d’Aguilar Marine Reserve;

·      E2 is an Impact Station to monitor the impacts of cable installation works on the coral communities at Tung Lung Chau;

·      E6 is an Impact Station to monitor the impacts of cable installation works on the coral communities at Tai Long Pai (the Gradient Station is not set due to the short distance of this Impact Station to nearby proposed cable works which may affect the cable laying works);

·      E9 is an Impact Station to monitor the impacts of cable installation works on the coral communities at Cape Collison (the Gradient Station is not set due to the short distance of this Impact Station to nearby proposed cable works which may affect the cable laying works);

·      F1 is an Impact Station to monitor the impacts of cable installation works on the Tung Lung Chau Fish Culture Zone;

·      G3 is a Gradient Station between F1 and the cable alignment;

·      G4 is a Gradient Station between E2 and the cable alignment;

·      G7 is a Gradient Station between E1 and the cable alignment; and

·      C2 is a Control Station (approximately 3.4 km from the proposed cable alignment) for Zone B.  It is not supposed to be influenced by the cable laying works due to its remoteness to the construction works.


Table 2.1        Water Quality Monitoring Stations

Monitoring Station

Nature

Easting

Northing

B1

Impact Station (Beach)

843557

811853

B2

Impact Station (Beach)

844062

810369

B3

Impact Station (Beach)

843988

809902

E1

Impact Station (Marine Reserve)

845474

810605

E2

Impact Station (Coral Communities)

845203

815205

E6

Impact Station (Coral Communities)

845321

816718

E9

Impact Station (Coral Communities)

843557

811853

F1

Impact Station (Fish Culture Zone)

847196

811056

G3

Gradient Station

846099

812826

G4

Gradient Station

846583

810809

G7

Gradient Station

845946

808583

C2

Control Station

849603

811528

2.2                                      Sampling and Testing Methodology

2.2.1                                Monitoring Parameters

The parameters measured in situ were:

·      Dissolved Oxygen (DO) (% saturation and mg L-1)

·      Salinity (ppt)

·      Temperature (ºC)

·      Turbidity (NTU)

The only parameter to be measured in the laboratory was:

·      Suspended solids (SS) (mg L-1)

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

2.2.2                                Monitoring Equipment

Table 2.2 summaries the equipment used for the baseline water quality monitoring.

Table 2.2        Equipment used during the Baseline Water Quality Monitoring Programme

Equipment

Model

Global Positioning Device

Garmin etrex 10

Water Depth Gauge

Speedtech Instrument SM-5A

Water Sampling Equipment

1510 Kemmerer Water Sampler

Salinity, DO, Temperature Measuring Meter

YSI Pro 2030

Current Velocity and Direction

Flow Probe FP11

Turbidity Meter

HACH Model 2100Q Turbid Meter

 

2.2.3                                Monitoring Frequency and Timing

The water monitoring was carried out on three occasions (days) and the intervals between two sets of monitoring were not less than 36 hours.  The water quality sampling was undertaken within a 4 hour window of 2 hour before and 2 hour after mid flood and mid-ebb tides.  The tidal range selected for the baseline monitoring was at least 0.5 m for both flood and ebb tides as far as practicable. 

Reference were made to the predicted tides at Tai Miu Wan, which is the tidal station nearest to the Project Site, published on the website of the Hong Kong Observatory ([1]).  Based on the predicted tidal levels at Tai Miu Wan, the baseline water quality monitoring was conducted between 17 September 2012 and 21 September 2012, following the schedule presented in Annex A.  Schedule for baseline monitoring has been submitted to the Contractor, Independent Environmental Checker (IEC), Engineer Representative (ER) and Environmental Protection Department (EPD) one week prior to the commencement of the monitoring works.

2.2.4                                Sampling/ Testing Protocol

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

For the on-site calibration of field equipment, the BS 1427: 1993, Guide to Field and On-Site Test Methods for the Analysis of Waters was observed.  Sufficient stocks of spare parts were maintained for replacements when necessary.  Backup monitoring equipment was made available.

Water samples for SS measurements were collected in high density polythene bottles, packed in ice (cooled to 4° C without being frozen), and delivered to a HOKLAS laboratory as soon as possible after collection.

Two replicate samples were collected from each of the monitoring events for in situ measurement and lab analysis.

2.2.5                                Laboratory Analysis

All laboratory work was carried out in a HOKLAS accredited laboratory.  Water samples of about 1,000 mL were collected at the monitoring and control stations for carrying out the laboratory determinations.  The determination work started within the next working day after collection of the water samples.  The SS laboratory measurements were provided within 2 days of the sampling event (48 hours).  The analyses followed the standard methods as described in APHA Standard Methods for the Examination of Water and Wastewater, 19th Edition, unless otherwise specified (APHA 2540D for SS).

The QA/QC details were in accordance with requirements of HOKLAS or another internationally accredited scheme (Annex C)

2.2.6                                Sampling Depths & Replication

Each station was sampled and measurements/ water samples were taken at three depths, namely, 1 m below water surface, mid-depth and 1 m above sea bed, except where the water depth less than 6 m, the mid-depth station may be omitted.  For stations that are less than 3 m in depth, only the mid-depth sample was taken.

For in situ measurements, duplicate readings were made at each water depth at each station.  Duplicate water samples were collected at each water depth at each station.

2.3                                      Baseline Monitoring Results

The monitoring data and graphical presentations for baseline water quality monitoring are provided in Annex D.  No marine construction activities were observed in the vicinity of the monitoring stations during the baseline monitoring.  No other major activities influencing water quality were identified during the monitoring period, and weather conditions were generally calm during the baseline monitoring period. 

The observations from the monitoring results are as following:

·      For all monitoring stations, water quality was variable throughout the baseline monitoring period and this represented natural fluctuation in water quality ;

·      Fluctuation of Dissolved Oxygen (DO) was observed during mid-flood, whilst DO levels fluctuated within a limited range.  Hence, it is considered that DO levels between Sensitive Receivers and Control Stations are similar in average although fluctuation exists;

·      DO levels at all depths were generally high for all samples, DO levels <4 mg L-1 were not recorded;

·      Relatively higher levels of turbidity were recorded at Sensitive Receiver Station E9 during mid-ebb and mid-flood tidal condition;

·      Higher levels of suspended solids (SS) were recorded at Sensitive Receiver Station E9 during both mid-ebb and mid-flood; and

·      The above sporadic patterns of relatively high levels of turbidity and SS at the water monitoring stations are considered to be a characteristic of water quality in this area of Hong Kong.

2.4                                      Action and Limit Levels

The Action and Limit Levels were set in the EM&A Manual and the proposed Action and Limit Levels were determined as shown in Table 2.3.

Table 2.3        Determination of Action and Limit Levels for Water Quality

Parameter

Action Level

Limit Level(d)

SS in mgL-1

(Depth-averaged) (a) (c)

95%-ile of baseline data or

99%-ile of baseline data, and

20% exceedance of value at any impact station compared with corresponding data from control station

30% exceedance of value at any impact station compared with corresponding data from  control station

DO in mgL-1 (b)

Surface and Middle

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

Surface and Middle

5mg/L or 1%-ile of baseline for surface and middle layer

Bottom

5%-ile of baseline data for bottom layers

Bottom

2mg/L or 1%-ile of baseline data for bottom layer

Turbidity in NTU (Depth-averaged) (a) (c)

95%-ile of baseline data, or

99%-ile of baseline data, and

20% exceedance of value at any impact station compared with corresponding data from control station

30% exceedance of value at any impact station compared with corresponding data from  control station

Notes:

a.      “Depth-averaged” is calculated by taking the arithmetic means of reading of all sampled depths.

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

c.      For SS and turbidity, non-compliance of the water quality limits occurs when monitoring result is higher than the limits.

d.      Limit level for DO was derived from the Water Quality Objectives (WQO) for Junk Bay, Eastern Buffer, and Mirs Bay Water Control Zones under the Water Pollution Control Ordinance (WPCO) Chapters 358L, 358Y, and 358I respectively.

 

The Action and Limit Levels have been determined based on baseline water quality monitoring data for all monitoring stations in Zone B.  The results are presented in Table 2.4.  Please note that the results are used to determine the Action and Limit Levels for the cable laying works to be undertaken in Zone B.


Table 2.4        Action and Limit Levels for Water Quality

Parameter

Action Level

Limit Level

SS in mgL-1

(Depth-averaged) (a) (c)

95%-ile of baseline data

(4.09 mg L-1), or

99%-ile of baseline data

(4.60 mg L-1) , and

20% exceedance of value at any impact station compared with corresponding data from control station

30% exceedance of value at any impact station compared with corresponding data from  control station

DO in mgL-1 (b)

Surface and Middle(d)

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

(4.72 mg L-1)

Surface and Middle(d)

5mg/L or 1%-ile of baseline for surface and middle layer

(4.57 mg L-1)

Bottom

5%-ile of baseline data for bottom layers

(4.52 mg L-1)

Bottom

2mg/L or 1%-ile of baseline data for bottom layer

(4.44 mg L-1)

Turbidity in NTU (Depth-averaged) (a) (c)

95%-ile of baseline data

(3.01 NTU), or

99%-ile of baseline data

(3.13 NTU), and

20% exceedance of value at any impact station compared with corresponding data from control station

30% exceedance of value at any impact station compared with corresponding data from  control station

Notes:

e.     “Depth-averaged” is calculated by taking the arithmetic means of reading of all sampled depths.

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

g.     For SS and turbidity, non-compliance of the water quality limits occurs when monitoring result is higher than the limits.

h.     The Action and Limit Level for DO for surface and middle layer were calculated from the combined pool of baseline surface layer data and baseline middle layer data.

3                                            conclusion

Baseline water quality monitoring in Zone B has been conducted between 17 September 2012 and 21 September 2012 at 12 designated monitoring stations (including 8 Sensitive Receiver Stations, 3 Gradient Stations and 1 Control Station).  The monitoring was conducted in 3 days, at mid-flood and mid-ebb tides, at three depths (surface, middle and bottom).  The intervals between two sets of monitoring were not less than 36 hours.  During the monitoring period, no major activities influencing water quality were observed in the vicinity of the Project’s marine works area.  Water quality monitoring results are, therefore, considered to be representative of the baseline conditions of the areas where marine works will be undertaken for the Project.

The baseline monitoring results were used to determine the Action and Limit Levels for the DO, SS and turbidity for impact monitoring to be conducted at Zone B throughout the construction phase of the Project.

 



([1])        Hong Kong Observatory (2012) http://www.hko.gov.hk/tide/eQUBtide.htm [Accessed in March 2012]