1 introduction

ERM-Hong Kong, Limited (ERM) was appointed by Tata Communications (Bermuda) Ltd (formerly Videsh Sanchar Nigam Limited (VSNL)) as the Monitoring Team (MT) to implement the Environmental Monitoring and Audit (EM&A) programme for the VSNL Intra Asia Submarine Cable System – Deep Water Bay (thereinafter called the (‘Project’)).

1.1 Purpose of the Report

This is the fourth Weekly Impact Monitoring Report, which summarises the impact monitoring results and audit findings for the EM&A programme during the reporting period from 22 May to 28 May 2009.

1.2 Structure of the Report

The structure of the report is as follows:

Section 1 : Introduction

Details the background, purpose and structure of the report.

Section 2 : Project Information

Summarises background and scope of the project, the construction works undertaken and the status of Environmental Permits/Licenses during the reporting period.

Section 3 : Water Quality Monitoring Requirements

Summarises the monitoring parameters, monitoring programmes, monitoring methodologies, monitoring frequency, monitoring locations, Action and Limit Levels, and Event / Action Plans.

Section 4 : Monitoring Results

Summarises the monitoring results obtained in the reporting period.

Section 5 : Environmental Non-conformance

Summarises any monitoring exceedance, environmental complaints and environmental summons within the reporting period.

Section 6 : Future Key Issues

Summarises the monitoring schedule for the next week.

Section 7 : Conclusions

Presents the key findings of the impact monitoring results.

2 Project Information

2.1 Background

Tata Communications (Bermuda) Ltd (formerly Videsh Sanchar Nigam Limited (VSNL)) proposes to install a submarine telecommunications cable, which will run from Deep Water Bay and through southeast Hong Kong offshore waters. The cable landing site will be at the western edge of Deep Water Bay beach at an existing cable landing manhole location. From Deep Water Bay, the cable will extend southwards towards the East Lamma Channel. Near to Round Island, the cable will turn approximately parallel to the East Lamma Channel passing to the south of Po Toi Island. The cable will then run eastward close to the boundary of HKSAR waters and then out beyond Hong Kong territorial waters into the South China Sea. At the southeast offshore waters, it will be necessary to install a grout mattress to protect the cable where it crosses Hong Kong Electric Co., Ltd’s (HKE) gas pipeline. A map of the proposed cable route is presented in Figure 2.1.

In August 2007, a Project Profile (PP) included an assessment of the potential environmental impacts associated with the installation of the submarine cable circuit 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 application for Permission to apply directly for an Environmental Permit (EP). The Environmental Protection Department, subsequently issued an Environmental Permit (EP-294/2007) and Further Environmental Permit (FEP-01/294/2007). Amendments to the permitting requirements were incorporated into the Environmental Permit to address potential environmental impacts associated with cable crossings over the HKE’s gas pipeline in southeast Hong Kong waters. Under the requirements of Condition 3 of the EP, an EM&A programme as set out in the Environmental Monitoring and Audit Manual (EM&A Manual) is required to be implemented. In accordance with the EM&A Manual, impact monitoring of water quality is required for the Project.

Baseline Monitoring was conducted near Deep Water Bay (ie Zones A and E) between 27 February 2009 and 9 March 2009 and the results were presented in the Baseline Water Quality Monitoring Report Part A. Baseline monitoring for the Po Toi section of works was undertaken from 27 February 2009 to 13 March 2009 and the Baseline Water Quality Monitoring Report Part B presented the results of the monitoring data for Zones B to D near Po Toi Island.

Impact Monitoring has been carried out at Deep Water Bay (ie Zone A) since 25 March 2009. This report presents results of the data from monitoring stations within Zone A during the cable installation works in the reporting week. Results of the impact monitoring data will therefore be compared against the results of the Baseline Environmental Monitoring Part A.

2.2 Marine Construction Works Undertaken during Reporting Week

The cable installation barge “CB Networker” installs the cable in three phases:

· Phase I – Locate in-service cables by divers (ie completed);

· Phase II – Conduct route clearance and pre-lay trial run of burial tool “Injector” (completed); and

· Phase III – Install cable along the proposed route using the burial tool “Injector”.

A summary of the major works undertaken during the reporting week is shown in Table 2.1.

Table 2.1 Summary of Marine Works Undertaken During the Reporting Week

Date	Works Area	Activity
22 May 2009	Zone A	Onboard activities to join the Pre-laid shore end to the cable on board the barge
23 May 2009	Zone A	Preparation works for Phase III Cable Installation in the morning. Weather downtime afterwards
24 May 2009	Zone A	Weather downtime
25 May 2009	Zone A	Weather downtime
26 May 2009	Zone A	Weather downtime
27 May 2009	Zone A	Weather downtime
28 May 2009	Zone A	Weather downtime

2.3 Status of Environmental Approval Documents

A summary of the relevant permits, licences, notifications and/or reports on environmental protection for this Project is presented in Table 2.2.

Table 2.2 Summary of Environmental Licensing, Notification, Permit and Reporting Status

Permit / Licence / Notification / Report	Reference	Validity Period	Remarks
Environmental Permit	(EP-294/2007)	Throughout the construction period	Granted on 23 November 2008
Further Environmental Permit	(FEP-01/294/2007)	Throughout the construction period	Granted on 9 July 2008
EM&A Manual	-	Throughout the construction period	Approved by EPD on 12 March 2009
Baseline Water Quality Monitoring Report (Part A)	-	Throughout the construction period for Zones A and E	Approved by EPD on 1 April 2009
Baseline Water Quality Monitoring Report (Part B)	-	Throughout the construction period for Zones B to D	Approved by EPD on 30 April 2009

3 Water Quality Monitoring Requirements

3.1 Monitoring Locations

In accordance with the EM&A Manual, during the installation of the cable in Zone A, water quality sampling was undertaken at stations situated around the cable laying works at Deep Water Bay (ie Zone A). The locations of the sampling stations within Zone A are shown in Figure 3.1.

· S1 and S2 are situated at the two Seawater Intake Points in Deep Water Bay. They are within 500 m west/northwest of the cable alignment at Deep Water Bay for monitoring the effect of cable laying works in the area. The monitoring works started when the cable installation works were carried out in Zone A;

· S3 is a Sensitive Receiver used to monitor the water quality condition of the Coastal Protection Areas at Middle Island. The monitoring works took place when the cable installation works were conducted in Zone A;

· B1 is an Impact Station used to monitor the effect of the construction activities on Deep Water Bay Beach when the cable installation works were undertaken in Zone A; and

· R1 is a Control Station for S1, S2, S3 and B1 at Deep Water Bay which is not supposed to be influenced by the cable laying works due to its remoteness from the construction works.

The co-ordinates of Zone A and the above monitoring stations are listed in Table 3.1 and Table 3.2, respectively.

Table 3.3.1 Co-ordinates of Starting Points and Ending Points for Zone A (HK Grid)

Zone	Starting Point		Ending Point
Zone	Easting	Northing	Easting	Northing
A	837029.763	811601.699	836367.572	810545.975

Table 3.3.2 Co-ordinates of Impact Monitoring Stations in Zone A (HK Grid)

Station	Nature	Corresponding Control Station	Easting	Northing
S1	Seawater Intakes	R1	836538.669	811528.535
S2	Seawater Intakes	R1	836195.047	810956.409
S3	Coastal Protection Areas	R1	836677.103	810666.744
B1	Gazetted Beach	R1	837241.114	811498.400
R1	Control Station	-	835951.109	809052.535

3.2 Monitoring Parameters and Frequency

The impact water quality monitoring was conducted in accordance with the requirements stated in the EM&A Manual. These are presented below.

3.2.1 Monitoring Parameters

Parameters measured in situ were:

· dissolved oxygen (DO) (% saturation and mg L^-1);

· temperature (°C);

· turbidity (NTU); and

· salinity (‰).

The only parameter measured in the laboratory was:

· suspended solids (SS) (mgL^-1).

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

3.2.2 Monitoring Frequency

Impact Monitoring at S1, S2, S3, B1 and R1 took place when the cable installation works were undertaken within 500 m (Zone A) of monitoring stations S1, S2, S3 and B1. The sampling works ceased when no cable installation works were conducted inside Zone A.

Impact monitoring was carried out during the barge operating hours, normally covering both mid-flood and mid-ebb tidal conditions, until water quality monitoring was not required.

In-situ and SS data of the control and impact stations within Zone A were collected daily during mid-flood and mid-ebb tidal states (Table 3.3), unless the mid-ebb tide and/or the mid-flood tide were not occurring during the monitoring period. In addition, continuous in-situ measurements were taken at the impact monitoring stations, ie B1, S1, S2 and S3, at 30- to 60- minute intervals (subject to the weather conditions and travelling time between stations) within Zone A. The monitoring frequency and parameters for Impact Monitoring are summarised in Table 3.3.

Table 3.3 Monitoring Frequency and Parameters for Impact Monitoring at Zone A

Zone	Station Type	Monitoring Station	Monitoring Frequency	Monitoring Parameter
Zone	Station Type	Monitoring Station	Monitoring Frequency	Mid-ebb Tide / Mid-flood Tide	30- to 60- Minute Interval
A	Control	R1	Daily when cable installation works undertaken in Zone A	Temperature, Turbidity, Salinity, DO, SS	-
A	Impact	S1, S2, S3 and B1	Daily when cable installation works undertaken in Zone A	Temperature, Turbidity, Salinity, DO, SS	Temperature, Turbidity, Salinity, DO

3.3 Monitoring Equipment and Methodology

3.3.1 Monitoring Equipment

Dissolved Oxygen, Temperature, Salinity, Turbidity Measuring Equipment

The instrument was a portable, weatherproof multi-parameter measuring instrument (YSI 6820) complete with cables, multi-probe sensor, comprehensive operation manuals, and was operable from a DC power source. It was capable of measuring:

· dissolved oxygen levels in the range of 0 – 50 mg L^-1; and 0-500% saturation;

· temperature of -5 to 50 °C;

· turbidity levels between 0-1000 NTU (response of the sensor was checked with certified standard turbidity solutions before the start of measurement); and,

· salinity in the range of 0-40 ppt (checked with 30 ppt Salinity solutions before the start of the measurement).

Water Depth Gauge

The water depth gauge affixed to the bottom of the water quality monitoring vessel was used.

Current Velocity and Direction

Current velocity and direction was estimated by conducting float tracking.

Positioning Device

A Global Positioning System (GPS) was used (C-Navigator World DGPS, GPS 72A) during monitoring to ensure the accurate recording of the position of the monitoring vessel before taking measurements. The use of DGPS was used for positioning device, which was well calibrated at an appropriate checkpoint.

Water Sampling Equipment

Water samples for suspended solids measurement were collected by the use of a multi-bottle water sampling system (General Oceanics Inc., Rosette Sampler ROS02), consisting of PVC bottles of more than two litres, which could be effectively sealed with cups at both ends. The water sampler had a positive latching system to keep it open and prevent premature closure until released by a messenger when the sampler was at the selected water depth.

3.3.2 Monitoring Methodology

Timing & Frequency

In-situ and SS data were collected daily at both control and impact stations within Zone A provided that the monitoring period had covered the mid-flood tide and/or mid-ebb tide. The water quality sampling was undertaken within a 3 hour window of 1.5 hours before and 1.5 hours after mid-flood and mid-ebb tides. Tidal range for flood and ebb tides was not less than 0.5m for capturing representative tides. Continuous In-situ measurements were taken at 30- to 60- minute intervals (subject to the weather conditions and travelling time between stations) for each impact station within Zone A.

Reference was made to the predicted tides at Waglan Island, which is the tidal station nearest to the Project site, published on the website of Hong Kong Observatory([1]). Based on the predicted water levels at Waglan Island, the impact water quality monitoring was conducted following the schedule presented in Annex A.

Duplicate samples were collected from each of the monitoring events for in situ measurements and laboratory analysis.

Depths

Each station was sampled and measurements were taken at three depths, 1 m below the sea surface, mid depth and 1m above the sea bed.

Protocols

The multi-parameter measuring instrument (YSI 6820) was checked and calibrated by an HOKLAS accredited laboratory before use. Onsite calibration was also carried out to check the responses of sensors and electrodes using certified standard solutions before each use. Sufficient stocks of spare parts were maintained for replacements when necessary, and 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 an HOKLAS accredited laboratory as soon as possible after collection.

Laboratory Analysis

All laboratory work was carried out by 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 analyses followed the standard methods as described in APHA Standard Methods for the Examination of Water and Wastewater, 19^th Edition, unless otherwise specified (APHA 2540D for SS).

The QA/QC details were in accordance with requirements of HOKLAS or another internationally accredited scheme (for details refer to Annex B).

3.3.3 Action and Limit Levels

The Action and Limit levels for Zones A and E, which were established based on the results of Baseline Environmental Monitoring Part A, are presented in Tables 3.4.

Table 3.4 Proposed Action and Limit Levels of Water Quality for Zones A and E

Parameter	Action Level	Limit Level
Dissolved Oxygen (DO) ⁽¹⁾	Surface and Mid-depth ⁽²⁾	Surface and Mid-depth ⁽²⁾
	5%-ile of baseline data for surface and middle layer = 6.59 mg L^-1	1%-ile of baseline data for bottom layer = 6.42 mg L^-1

	Bottom	Bottom
	5%-ile of baseline data for bottom layers = 6.58 mg L^-1	1%-ile of baseline for bottom layer = 6.42 mg L^-1

Depth-averaged Suspended Solids (SS) ^{(3) (4)}	95%-ile of baseline data = 7.91 mg L^-1	99%-ile of baseline data = 8.96 mg L^-1
	or 120% of control station's SS at the same tide of the same day	or 130% of control station's SS at the same tide of the same day

Depth-averaged Turbidity (Tby) ^{(3) (4)}	95%-ile of baseline data = 5.17 NTU	99%-ile of baseline data = 5.72 NTU
	or 120% of control station's Tby at the same tide of the same day	or 130% of control station's Tby at the same tide of the same day

Notes: (1) For DO, non-compliance of the water quality limits occurs when monitoring result is lower than the limits. (2) The Action and Limit Levels for DO for Surface & Middle layer were calculated from the combined pool of baseline surface layer data and baseline middle layer data. (3) “Depth-averaged” is calculated by taking the arithmetic means of reading of all three depths. (4) For turbidity and SS, non-compliance of the water quality limits occurs when monitoring result is higher than the limits.

3.3.4 Event and Action Plan

The Event and Action Plan for water quality monitoring which was stipulated in the EM&A Manual is presented in Table 3.5.

Table 3.5 Event Action Plan for Water Quality

Event	Contractor
Action Level Exceedance	Step 1 - repeat sampling event. Step 2 – identify source(s) of impact and confirm whether exceedance was due to the construction works; Step 3 – inform EPD, AFCD and LCSD and confirm notification of the non-compliance in writing; Step 4 - discuss with cable installation contractor the most appropriate method of reducing suspended solids during cable installation (e.g. reduce cable laying speed/volume of water used during installation). Step 5 - repeat measurements after implementation of mitigation for confirmation of compliance. Step 6 - if non compliance continues - increase measures in Step 4 and repeat measurements in Step 5. If non compliance occurs a third time, suspend cable laying operations.
Limit Level Exceedance	Undertake Steps 1-5 immediately, if further non compliance continues at the Limit Level, suspend cable laying operations until an effective solution is identified.

Event

Contractor

Action Level Exceedance

Step 1 - repeat sampling event.

Step 2 – identify source(s) of impact and confirm whether exceedance was due to the construction works;

Step 3 – inform EPD, AFCD and LCSD and confirm notification of the non-compliance in writing;

Step 4 - discuss with cable installation contractor the most appropriate method of reducing suspended solids during cable installation (e.g. reduce cable laying speed/volume of water used during installation).

Step 5 - repeat measurements after implementation of mitigation for confirmation of compliance.

Step 6 - if non compliance continues - increase measures in Step 4 and repeat measurements in Step 5. If non compliance occurs a third time, suspend cable laying operations.

Limit Level Exceedance

Undertake Steps 1-5 immediately, if further non compliance continues at the Limit Level, suspend cable laying operations until an effective solution is identified.

4 Impact Monitoring Results

Daily monitoring events were scheduled between 22 May and 28 May 2009 at Deep Water Bay (ie Zone A). All monitoring events at all designated monitoring stations within Zone A were performed on schedule.

4.1 Data Collected During Mid-Ebb and/or Mid-Flood Tidal Conditions

The monitoring data taken during the mid-ebb and/or mid-flood tidal conditions for Zone A are presented in Annex C and compared against the baseline monitoring results in Figures C1 - C4. The impact monitoring results, except DO, obtained during this week were mostly comparable to the results recorded during the baseline monitoring. As shown in Figures C1 and C2, dissolved oxygen levels at all the monitoring stations have started to decrease since 22 May 2009 and then dropped close to or below the Limit Levels. It should be noted that DO levels measured at all the impact stations were of similar magnitude to DO levels detected at the control station. This implies the background levels of DO were also relatively low.

Depth-averaged turbidity and suspended solids were generally compliant with the Action and Limit Levels; however, SS exceedances were noted at stations B1, S1 and S2 on 22 May 2009. There was an exceedance of the Action Level for turbidity at station B1 on 28 May 2008. A review of the above exceedance is discussed in the following section.

4.1.1 Exceedance on 22 May 2009

Exceedances of the Action and Limit Levels for Bottom Dissolved Oxygen (DOB) and Depth-averaged Suspended Solids (SS) were recorded on 22 May 2009 (Table 4.1).

The Contractor confirmed that the Networker was on a four point mooring in Zone A throughout the day of 22 May 2009. Onboard activities were undertaken to join the Pre-laid shore end to the cable on board the barge. Neither the injector nor the thrusters were in operation.

The levels of suspended solids measured at stations S1, S2 and B1 were 0.1 – 1.1 mg/L higher than 120% of the control station’s SS whilst these values did not exceed the Action and Limit Levels derived from the baseline data. In addition, SS levels of all impact stations did not show non-compliance during the following mid-flood tide. It was, therefore, considered that the SS exceedances were more likely to be caused by localised factors or temporary tidal influence rather than the Project works.

The DOB concentrations recorded at stations S1 and S3 were 0.05 – 0.22 mg/L below the Action Level. However, the DOB of the water samples taken at the control station R1 was even lower than the Limit Level during both the mid-ebb and mid-flood tidal conditions. This indicates the ambient DOB levels were relatively low and the decrease in DOB could be due to natural fluctuation. Nevertheless, the DOB levels at stations S1 and S3 were compliant with the Water Quality Objective of not less than 2 mg/L for 90% of samples for bottom DO.

No spatial trend could be drawn from the monitoring results and hence there were no indications of pollution sources coming from the Project works area. The exceedances were, therefore, considered unlikely related to the Project works.

Table 4.1 Exceedances of Action and Limit Levels for Bottom Dissolved Oxygen and Depth-averaged Suspended Solids on 22 May 2009

Exceedance Log No.	0096120_22 May 09_SS_E_Station S1 0096120_22 May 09_SS_E_Station S2 0096120_22 May 09_SS_E_Station B1 0096120_22 May 09_DOB_E_Station S1 0096120_22 May 09_DOB_E_Station S3 0096120_22 May 09_DOB_F_Station S3
Sampling date	22 May 2009
Monitoring station	B1, S1, S2 and S3
Parameter	Depth-averaged Suspended Solids (mg/L) Dissolved Oxygen, Bottom (DOB) (mg/L)
Action Levels	Mid-Ebb	DOB = 6.58 (baseline data) SS : 120% of R1 = 6.4 or 7.91 (baseline data)
	Mid-Flood	DOB = 6.58 (baseline data) SS : 120% of R1 = 10.0 or 7.91 (baseline data)
Limit Levels	Mid-Ebb	DOB = 6.42 (baseline data) SS : 130% of R1 = 6.9 or 8.96 (baseline data)
	Mid-Flood	DOB = 6.42 (baseline data) SS : 130% of R1 =10.8 or 8.96 (baseline data)
Measured Levels at Station B1	Mid-Ebb	SS = 6.67	(exceeds Action Level)
	Mid-Flood	SS = 5.67
Measured Levels at Station S1	Mid-Ebb	SS = 6.50 DOB = 6.36	(exceeds Action Level) (exceeds Limit Level)
	Mid-Flood	SS = 4.17 DOB = 8.08
Measured Levels at Station S2	Mid-Ebb	SS = 7.50	(exceeds Limit Level)
	Mid-Flood	SS = 3.85
Measured Levels at Station S3	Mid-Ebb	DOB = 6.53	(exceeds Action Level)
	Mid-Flood	DOB = 6.51	(exceeds Action Level)

4.1.2 Exceedance on 23 May 2009

Exceedances of the Action and Limit Levels for Bottom Dissolved Oxygen (DOB) were recorded at stations S2 and S3 on 23 May 2009 (Table 4.2).

The Contractor confirmed that preparation works were undertaken on the morning of 23 May 2009 until the weather conditions became too severe to proceed. Starting from 12:00 hrs, the working vessel had been on a four point mooring in Zone A and no construction had been carried out afterwards. Neither the injector nor the thrusters were in operation.

Similar to 22 May 2009, the DOB levels detected at stations S2 and S3 were only 0.13 – 0.79 mg/L lower than the Action Levels but were higher than those recorded at the control station R1. It was also noted that the DOB of the water samples taken at the control station R1 exceeded the Limit Levels during both the mid-ebb and mid-flood tidal conditions. This implies the ambient DOB levels were still relatively low and the decrease in DOB could be due to natural fluctuation. No action was hence required. Nevertheless, the DOB levels at stations S1 and S3 were compliant with the Water Quality Objective of not less than 2 mg/L for 90% of samples for bottom DO.

Table 4.2 Exceedances of Action and Limit Levels for Bottom Dissolved Oxygen on 23 May 2009

Exceedance Log No.	0096120_23 May 09_DOB_E_Station S2 0096120_23 May 09_DOB_E_Station S3 0096120_23 May 09_DOB_F_Station S2 0096120_23 May 09_DOB_F_Station S3
Sampling date	23 May 2009
Monitoring station	S2 and S3
Parameter	Dissolved Oxygen, Bottom (DOB) (mg/L)
Action Levels	Mid-Ebb Mid-Flood	6.58 (baseline data)
Limit Levels	Mid-Ebb Mid-Flood	6.42 (baseline data)
Measured Levels at Station S2	Mid-Ebb	5.79	(exceeds Limit Level)
Measured Levels at Station S2	Mid-Flood	6.45	(exceeds Action Level)
Measured Levels at Station S3	Mid-Ebb	5.79	(exceeds Limit Level)
Measured Levels at Station S3	Mid-Flood	5.88	(exceeds Limit Level)

4.1.3 Exceedance form 24 May to 28 May 2009

Due to weather constraints, the working vessel had been on a four point mooring in Zone A awaiting safe conditions offshore to progress cable installation operations since the afternoon of 23 May 2009. No onboard or underwater construction activities had been undertaken during the period of 24 May and 28 May 2009. Neither the injector nor the thrusters were in operation. However, daily exceedances of Limit Levels for dissolved oxygen were recorded during the water quality monitoring in these five days.

It was observed that the DO concentrations measured at all the impact stations were comparable to those recorded at the control station R1 during this monitoring period (ie 24 May and 28 May 2009). Besides, non-compliances of DO levels were also noted at the control station R1. This suggests the ambient DO levels were relatively low and DO depletion was first detected in the bottom layer of the water column on 22 May 2009.

In the beginning of the week, the weather was sunny and hot (high solar radiation) which would favour thermal stratification. Freshwater input from the precipitation during the weekend (reducing salinity) could cause the density difference between the surface layer and the salty deep waters to be greater. The stratification could limit the circulation of oxygen between the layers of waters due to the density difference. Dissolved oxygen levels could decrease in the bottom layer because photosynthesis and contact with the air may be significantly reduced. The already reduced oxygen levels could be further depleted through the decomposition of organic matters washed into the marine waters during the rainstorm. This phenomenon is supported by the fact that DOB exceedances were noted whilst relatively high DO concentrations were measured at the surface and mid-depth on 22 May and 23 May 2009.

It is believed that the thermocline was broken by strong wind/wave or heavy rainstorm leading to mixing of oxygen-rich surface waters with oxygen-deficient bottom waters. There is the potential for all DO present in the waters to be rapidly removed for satisfying the oxygen demand resulting in further oxygen depletion throughout the water column in the subsequent days. Although such situation may last for a certain period of time due to the unstable weather conditions, DO concentrations measured at all impact stations were in compliance with the Water Quality Objectives for DO (ie not less than 2 mg/L for 90% of samples for bottom DO and not less than 4 mg/L for 90% of samples for depth-averaged DO).

This explains that the recent declining trends of dissolved oxygen and daily DO exceedances may be due to natural fluctuation (ie stratification followed by de-stratification).

It should be noted that although exceedances of the Action and Limit Levels for DO occurred, no non-compliances of the WQOs were reported.

Exceedances of the Action Levels for depth-averaged turbidity and SS were noted at station B1 on 28 May 2009 during the mid-ebb tide. The turbidity and SS levels measured at B1 was slightly higher than the Action Levels derived from the baseline data but these values were well below the 120% of the control station’s turbidity and SS. At the time of the monitoring event, station B1 was located upstream of the working vessel during the mid-ebb tide. Therefore, the turbidity and SS exceedances were considered to be caused by some localised activities in the vicinity of B1 which were not related to the project.

4.2 Continuous In-Situ Measurement Data

Continuous in-situ measurements were taken at the impact monitoring stations, ie B1, S1, S2 and S3, at 30- to 60- minute intervals (subject to the weather conditions and travelling time between stations) for Zone A and the results and the graphical presentations were included in Annex D.

In general, the water quality of Zone A was stable throughout each sampling day with the exception of some fluctuations in DO during the first few days.

5 Environmental Non-CONFORMANCES

5.1 Summary of Environmental Exceedance

Daily Notification of Exceedances (NOEs) with detailed investigation reports were issued to EPD and AFCD during the reporting period for recording water quality monitoring exceedances on dissolved oxygen, turbidity and suspended solids of the monitoring stations. The exceedances were examined against the Project works. Results of the detailed investigation indicated that none of the exceedances were attributed to the Project construction works.

5.2 Summary of Environmental Complaint

No complaints were received during the reporting period.

5.3 Summary of Environmental Summons and Prosecution

No summons or prosecution on environmental matters were received during the reporting period.

6 Future Key Issues

6.1 Key Issues For The Coming Month

Works to be taken for the coming monitoring period are summarised in Table 6.1.

Table 6.1 Construction Works to be Undertaken in the Coming Monitoring Period

Zone	Works to be taken
A	Phase III Cable Installation
E	Phase III Cable Installation
B	Phase III Cable Installation
C	Phase III Cable Installation
D	Phase III Cable Installation

6.2 Monitoring Schedule For The Coming Months

The tentative schedule of water quality monitoring for the coming week (ie 29 May to 4 June 2009) is presented in Annex A. The water sampling will be conducted at the same monitoring location as in this reporting week. However, the tentative schedule of the water quality monitoring is subject to continued operational progress and weather constraints.

7 Conclusions

This Weekly Impact Monitoring Report presents the EM&A work undertaken during the period from 22 May to 28 May 2009 in accordance with the EM&A Manual and the requirements under FEP-01/294/2007.

Daily exceedances of Action and Limit Levels for dissolved oxygen were recorded in the reporting week. Depth-averaged turbidity and suspended solids were generally compliant with the Action and Limit Levels with the exception of 22 May and 28 May 2009. Results of the detailed investigation indicated that none of the exceedances were attributed to the Project construction works.

No complaints and summons/prosecution were received during the reporting week.

The MT will keep track of the EM&A programme to verify compliance of environmental requirements and the proper implementation of all necessary mitigation measures.

([1]) Hong Kong Observatory (2009) http://www.hko.gov.hk/tide/eWLtide.htm

Annex A	Impact Monitoring Schedule
Annex B	QA/QC Results of Laboratory Testing for Suspended Solids
Annex C	Impact Water Quality Monitoring Results
Annex D	Continuous In-situ Measurement Data

Figure 2.1	The Route of the Proposed Cable System
Figure 3.1	Location of Water Quality Monitoring Stations (Zone A)

Executive Summary