Contents

Executive Summary                                                             

1                      introduction                                                                          

1.1                   Purpose of the Report                                                     

1.2                   Structure of the Report                                                

2                      Project Information                                                          

2.1                   Background                                                                           

2.2                   Marine Construction Works Undertaken during Reporting Week     

2.3                   Status of Environmental Approval Documents 

3                      Impact Water Quality Monitoring Requirements

3.1                   Monitoring Locations                                                       

3.2                   Monitoring Parameters                                                   

3.3                   Monitoring Equipment and Methodology               

4                      Impact Monitoring Results                                             

4.1                   Data Collected During Reporting Period             

4.2                   Exceedances During Reporting Period                   

5                      Environmental Non-CONFORMANCES                           

5.1                   Summary of Environmental Exceedance                

5.2                   Summary of Environmental Non-compliance        

5.3                   Summary of Environmental Complaint                    

5.4                   Summary of Environmental Summons and Prosecution

6                      Future Key Issues                                                                

6.1                   Key Issues For The Coming Reporting Period       

6.2                   Monitoring Schedule For The Coming Reporting

                        Period                                                                                        

7                      Conclusions                                                                           

 


LIST OF TABLES

Table 2.1     Summary of Environmental Licensing, Notification, Permit and Reporting Status

Table 3.1     Co-ordinates of Water Quality Impact Monitoring Stations in Zone A

Table 3.2     Co-ordinates of Water Quality Impact Monitoring Stations in Zone B

Table 3.3     Equipment Used during the Impact Water Quality Monitoring

Table 3.4     Monitoring Frequency and Parameters for Impact Monitoring in Zone A and Zone B

Table 3.5     Action and Limit Levels of Water Quality for Zones A

Table 3.6     Action and Limit Levels for Water Quality for Zone B

Table 4.1     Summary of Exceedances Occurring during the Reporting Week

Table 4.2     Exceedances of Action and Limit Levels on 8 October 2012

Table 4.3     Exceedances of Action and Limit Levels on 9 October 2012

Table 4.4     Exceedances of Action and Limit Levels on 10 October 2012

Table 4.5     Exceedances of Action and Limit Levels on 11 October 2012

Table 4.6     Exceedances of Action and Limit Levels on 13 October 2012

Table 4.7     Exceedances of Action and Limit Levels on 14 October 2012

 

 

LIST OF ANNEXES

Annex A

Impact Water Quality Monitoring Schedule

Annex B

QA/QC Results for Suspended Solids Testing

Annex C

Impact Water Quality Monitoring Results

 

 

 

Executive Summary

The submarine cable installation works for the Asia Submarine-cable Express (ASE) cable system were commenced on 8 October 2012.  This is the First Weekly Impact Water Quality Monitoring Report presenting the impact water quality monitoring conducted during the period from 8 October 2012 to 14 October 2012 in accordance with the Monitoring and Audit Manual (EM&A Manual).

Summary of Construction Works Undertaken during the Reporting Period

During the reporting period, submarine cable laying works in Zone A and B were undertaken and had been largely completed by the end of the week. 

Water Quality Monitoring

Seven monitoring events were scheduled in the reporting period in Zone A and Zone B.  Monitoring events at Zone A and Zone B designated monitoring stations were generally performed on schedule.

Environmental Non-conformance

Exceedances of Action and Limit Levels were recorded during the reporting week.  However, the exceedances were considered to reflect natural background fluctuation rather than to be caused by the Project.

No complaint and summons/prosecution was received during the reporting week.

Future Key Issues

The submarine cable installation works will be conducted in Zone C and from Zone C eastward to the boundary Hong Kong marine waters in the coming week.  Impact water quality monitoring will then be carried out in Zone C and cease once the cable installation barge moves out Zone C or no cable laying works are undertaken within Zone C.

 

 


1                                           introduction

ERM-Hong Kong, Limited (ERM) was appointed by NTT Com Asia (NTTCA) as the Environmental Team (ET) to implement the Environmental Monitoring and Audit (EM&A) programme for the installation of a telecommunication cable (Asia-Submarine-cable Express (ASE)) of approximately 7,200 km in length, connecting Japan and Singapore with branches to the Philippines, Hong Kong SAR (HKSAR) and Malaysia (thereinafter called the Project).

1.1                                      Purpose of the Report

This is the First Weekly Impact Water Quality Monitoring Report, which summarises the results of impact water quality monitoring as part of the EM&A programme during the reporting period from 8 October to 14 October 2012.

1.2                                      Structure of the Report

The structure of the Report is as follows:

Section 1 :  Introduction

Provides details of the background, purpose and report structure.

 

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 Plan.

 

Section 4 :  Monitoring Results

Summarises the water quality 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 reporting period.

 

Section 7 :  Conclusions

Presents the key findings of the impact monitoring results.

2                                           Project Information

2.1                                      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.  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 2.1.

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 programme as set out in the Environmental Monitoring and Audit Manual (EM&A Manual) is required to be implemented.  In accordance with Section 2 of the EM&A Manual, impact monitoring of marine water quality should be undertaken when the cable installation barge works in Zone A, Zone B and Zone C. 

Impact monitoring started on 8 October 2012, when the cable laying works commenced in Zone A.  During the reporting period, the impact monitoring was conducted on a daily basis as the cable laying works proceeded in Zone A and Zone B.  This Report therefore presents the monitoring results from the monitoring stations in Zone A and Zone B.

2.2                                      Marine Construction Works Undertaken during Reporting Week

Cable laying works in Zone A and Zone B were undertaken during the reporting week from 8 October 2012 to 14 October 2012, and had been largely completed by the end of the week.

2.3                                      Status of Environmental Approval Documents

A summary of the relevant permits, licences and reports on environmental protection for this Project is presented in Table 2.1.

Table 2.1        Summary of Environmental Licensing, Notification, Permit and Reporting Status

Permit / Licence / Notification / Report

Reference

Validity Period

Remarks

Environmental Permit

EP 433/2011

Throughout the construction and operation stages

 

Granted on 20 December 2011

EM&A Manual

-

Throughout the construction stage

 

Revised EM&A Manual submitted on 18 September 2012

Baseline Water Quality Monitoring Report (Zone A)

-

Throughout the construction period for Zone A

Submitted on 19 September 2012

Baseline Water Quality Monitoring Report (Zone B)

-

Throughout the construction period for Zone B

Submitted on 25 September 2012

Baseline Water Quality Monitoring Report (Zone C)

 

Throughout the construction period for Zone C

Submitted on 1 October 2012


3                                           Impact 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 the stations situated around the cable laying works in Zone A.  The locations of the sampling stations within Zone A are shown in Figure 3.1. 

·      E7 is the Impact Station located at Fat Tong Chau to monitor the impacts of cable installation works on the coral communities in the proximity;

·      E8 is an Impact Station to monitor the impacts of cable installation works on the coral communities along Junk Bay – South West;

·      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;

·      S1 is an Impact Station situated at the WSD Seawater Intake Point in Junk Bay.  It is located within 500 m north of the cable alignment at Junk Bay and set up to monitor the effect of cable laying works in the area; 

·      S2 is an Impact Station to monitor the impacts of cable installation works on the WSD Seawater Intake at Siu Sai Wan;

·      S3 is an Impact Station to monitor the impacts of cable installation works on the Pamela Youde Nethersole Eastern Hospital Cooling Water Intake at Heng Fa Chuen;

·      G1 is a Gradient Station between S1 and the cable alignment;

·      G2 is a Gradient Station between S2 and the cable alignment;

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

·      C1 is a Control Station (approximately 3 km from the proposed cable alignment) for Zone A.  It is not supposed to be influenced by the cable laying works due to its remoteness to the construction works.

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

Table 3.1        Co-ordinates of Water Quality Impact Monitoring Stations in Zone A

Monitoring Station

Nature

Easting

Northing

E7

Impact Station (Coral Community)

843779

814520

E8

Impact Station (Coral Community)

843111

815126

E9

Impact Station (Coral Community)

843557

811853

F1

Impact Station (Fish Culture Zone)

847196

811056

S1

Impact Station (Seawater Intakes)

847639

805900

S2

Impact Station (Seawater Intakes)

849587

805696

S3

Impact Station (Seawater Intakes)

845474

810605

G1

Gradient Station

845297

816282

G2

Gradient Station

844071

814784

G3

Gradient Station

846099

812826

C1

Control Station

842022

816547

In accordance with the EM&A Manual, during the installation of the cable in Zone B, water quality sampling was undertaken at the stations situated around the cable laying works in Zone B.  The locations of the sampling stations within Zone B are shown in Figure 3.2. 

·      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.

The co-ordinates of the above monitoring stations in Zone B are listed in Table 3.2.

Table 3.2        Co-ordinates of Water Quality Impact Monitoring Stations in Zone B

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

3.2                                      Monitoring Parameters

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

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, special phenomena and work activities undertaken around the monitoring and works area that may influence the monitoring results.

3.3                                      Monitoring Equipment and Methodology

3.3.1                                Monitoring Equipment

Table 3.3 summaries the equipment used for the impact water quality monitoring.

Table 3.3        Equipment Used during the Impact Water Quality Monitoring

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

 

3.3.2                                Monitoring Methodology

Timing & Frequency

In-situ data and SS data were collected during the cable installation works from 07:00 to 23:00 on a daily basis.  The impact monitoring schedule for the reporting period is presented in Annex A.

Impact monitoring at E7, E8, E9, F1, S1, S2, S3, G1, G2, G3 and C1 commenced when the cable installation barge works were within Zone A.  The sampling works ceased once the cable barge was outside Zone A or no cable laying works were being undertaken within Zone A.

Similarly, impact monitoring at C2, G3, G4, G7, B1, B2, B3, E1, E2, E6, E9 and F1 commenced when the cable installation barge works were within Zone B.  The sampling works ceased once the cable barge was outside Zone B or no cable laying works were being undertaken within Zone B.

Due to the weather conditions and travelling time between stations, in-situ and SS measurements were taken at the impact monitoring stations with approximately four-hour interval in Zone A and Zone B.  The monitoring frequency and parameters for Impact Monitoring are summarised in Table 3.4.

Table 3.4        Monitoring Frequency and Parameters for Impact Monitoring in Zone A and Zone B

Zone

Station Type

Monitoring Station

Monitoring Frequency

Monitoring Parameter

A

Control

C1

Daily at ~4-hour interval while cable installation works were being undertaken in Zone A

Temperature, Turbidity, Salinity, DO and SS

Gradient

G1, G2, G3

Impact

E7, E8, E9, F1, S1, S2, S3,

B

Control

C2

Daily at ~4-hour interval while cable installation works were being undertaken in Zone B

Temperature, Turbidity, Salinity, DO and SS

Gradient

G3, G4, G7

Impact

B1, B2, B3, E1, E2, E6, E9, F1

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

Depths

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.

Sampling/ Testing Protocols

All in situ monitoring instruments were checked, calibrated and certified by a laboratory accredited under HOKLAS or any other international accreditation scheme before use, 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.

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 B)

3.3.3                                Action and Limit Levels

The Action and Limit levels for Zones A, which were established based on the results of Baseline Environmental Monitoring (Zone A), are presented in Table 3.5.

Table 3.5        Action and Limit Levels of Water Quality for Zones A

Parameter

Action Level

Limit Level

SS in mgL-1

(Depth-averaged) (a) (c)

95%-ile of baseline data

(6.27 mg L-1), or

99%-ile of baseline data

(6.40 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

(4.36 mg L-1)

Surface and Middle(d)

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

(4.25 mg L-1)

Bottom

5%-ile of baseline data for bottom layers

(4.39 mg L-1)

Bottom

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

(4.33 mg L-1)

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

95%-ile of baseline data

(4.38 NTU), or

99%-ile of baseline data

(4.43 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.


The Action and Limit levels for Zones B, which were established based on the results of Baseline Environmental Monitoring (Zone B), are presented in Table 3.6.

Table 3.6        Action and Limit Levels for Water Quality for Zone B

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.

 

3.3.4                                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 3.7.


Table 3.7       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.


4                                           Impact Monitoring Results

A total of seven monitoring events were scheduled between 8 October and 14 October 2012.  Monitoring events at all designated monitoring stations within Zone A and Zone B were generally performed on schedule.  No major activities influencing the water quality were identified during the reporting period.

4.1                                      Data Collected During Reporting Period

Continuous water sampling was taken at the impact monitoring stations in Zone A and Zone B at approximately 4-hour intervals (subject to the weather conditions and travelling time between stations) on a daily basis.  In general, the water quality of Zone A and Zone B was stable throughout each sampling day though natural fluctuation existed.  Neither sudden drop in dissolved oxygen concentrations nor sharp increase in turbidity levels and suspended solid levels were observed on each monitoring day.  The results of the impact monitoring and their graphical presentations were included in Annex C.

Despite relatively stable water quality, exceedances of the Action and Limit Levels were recorded during the reporting week except 12 Oct 2012.  A summary of stations where exceedances were recorded is presented in Table 4.1.  Exceedances with detailed information of location and time were presented in Annex C. 

Table 4.1       Summary of Exceedances Occurring during the Reporting Week

Surface DO

Middle DO

Bottom DO

Depth-averaged Turbidity

Depth-averaged SS

Date

Exceedance of

Action Level

Limit Level

Action Level

Limit Level

Action Level

Limit Level

Action Level

Limit Level

Action Level

Limit Level

08/10

 

 

 

 

E9, S3

E9, S3

 

 

 

 

09/10

 

 

 

 

S1, S2, S3

S1

 

 

 

 

10/10

 

 

 

 

E9, S3

E9, S3

 

 

 

 

11/10

 

 

 

 

E9, S3

 

 

 

 

 

12/10

 

 

 

 

 

 

 

 

 

 

13/10

 

 

F1

 

 

 

E9, F1, B3

E9

E9, F1

E9

14/10

 

 

F1

 

 

 

E9, F1

E9

E9

E9

4.2                                      Exceedances During Reporting Period

4.2.1                                Exceedances on 8 October 2012

Exceedances of the Action and Limit Levels in bottom DO were recorded at Stations E9 and S3 in the 1st, 2nd and 3rd sampling rounds on 8 October 2012 (Table 4.2).

According to the daily barge operation report, there were some maintenance and repair works carried out by the Contractor and the burial operation (ie jetting works) did not start until 17:00 of 08 October 2012.  Jetting works were undertaken between 17:00 – 23:00 on the day.

As stated above, jetting works for the Project were not being undertaken when the exceedances were recorded in the 1st and 2nd rounds of marine water quality monitoring (ie 09:00 – 15:04).  Therefore, the exceedances of the Action/Limit levels at E9 and S3 in the first two rounds are considered as representing natural background fluctuations.

The exceedances of the Action Level at S3 in the 3rd round of marine water quality monitoring is marginal in nature, with merely 0.02 mg/L lower than the corresponding Action Level value (ie 4.39 mg/L).  When the sampling was carried out, the current direction was westward.  Given the fact that the bottom DO value at Gradient Station G2 (4.78 mg/L), which is situated between the barge and S3, was within the Action Level, the exceedance measured at the S3 was unlikely to be caused by the jetting works but should be considered as an occasional case and representing natural background levels during the time of monitoring.

Table 4.2        Exceedances of Action and Limit Levels on 8 October 2012

 

4.2.2                                Exceedances on 9 October 2012

Exceedances of the Action and Limit Levels in bottom DO were recorded at Stations S1, S2 and S3 in all four sampling rounds on 9 October 2012 (Table 4.3).

According to the daily barge operation report, there were preparation and equipment maintenance works carried out by the Contractor before the burial operation (ie jetting works) resumed at 11:30.  All marine works stopped at approximately 20:00 in the evening.  The actual time of jetting works on 09 Oct 2012 was between 11:30 to 20:00. 

As stated above, jetting works were not being undertaken when the exceedances were recorded in the 1st round and late stage of the 4th round of marine water quality monitoring (ie in the periods of 07:00 – 10:55 and 20:00 – 23:05).  Therefore, the exceedances of the Action/Limit levels at S1 in the 1st sampling round and S3 in the 4th round are considered as representing natural background fluctuations rather than a result of the cable installation works.

Despite the Action Level exceedance at S1 in the 2nd sampling round, the bottom DO value (4.34 mg/L) was higher than that measured at the same station in the 1st round (4.28 mg/L) when jetting works had yet to start and was not expected to impose any impact.  The bottom DO at S1 continued to increase and was found to be compliant with the water quality limit in the 3rd sampling round when jetting works resumed after 11:30 and were taking place at the time of sampling (11:40 - 11:55).  Therefore the exceedance measured at the S1 in the 2nd round was unlikely to be caused by the jetting works but should be considered as representing natural background levels during the time of monitoring.     

The exceedance of the Action Level at S2 in the 3rd round of marine water quality monitoring is an occasional case that occurred only once among all four sampling rounds.  The exceedance of the Action Level at S3 in the 3rd round is marginal in nature, with merely 0.03 mg/L lower than the corresponding Action Level value (ie 4.39 mg/L).  When the sampling at S2 and S3 was carried out in the 3rd round, the current direction was westward.  Given the fact that the bottom DO value at Gradient Station G2 (4.71 mg/L), which is situated between the barge and S2/S3, was within the Action Level, the exceedances measured at S2 and S3 were unlikely to be caused by the jetting works but should be considered as representing natural background levels during the time of monitoring.

Table 4.3        Exceedances of Action and Limit Levels on 9 October 2012


4.2.3                                Exceedances on 10 October 2012

Exceedances of the Action and Limit Levels in bottom DO were recorded at Stations E9 and S3 in the 1st and 2nd sampling rounds on 10 October 2012 (Table 4.4).

According to the daily barge operation report, the Contractor did not conduct any jetting works until 15:00 due to unfavourable weather conditions on that day.  Between 13:00 – 15:00, there were preparation and equipment maintenance works carried out before the burial operation (ie jetting works) resumed.  Cable laying works stopped at approximately 16:00 in the afternoon due to restriction to cross the Tathong Channel until 17:00 as per recommendation from the Marine Department.  The actual time of jetting works on 10 Oct 2012 was between 15:00 - 16:00. 

As stated above, jetting works were not being undertaken when the exceedances were recorded in the 1st round of marine water quality monitoring (ie 07:00 – 11:01).  Therefore, the exceedances of the Limit levels at E9 and S3 in the 1st sampling round are considered as representing natural background fluctuations rather than a result of the cable installation works

Despite the Action Level exceedance at S3 in the 2nd sampling round, the bottom DO value (4.35 mg/L) was higher than that measured at the same station in the 1st round (4.25 mg/L) when jetting works had yet to start and was not expected to impose any impact.  The bottom DO at S3 continued to increase and was found to be compliant with the water quality limit in the 3rd sampling round when jetting works resumed after 15:00 and were taking place at the time of sampling (15:05 - 19:03).  Therefore the exceedance measured at the S3 in the 2nd round was unlikely to be caused by the jetting works but should be considered as representing natural background levels during the time of monitoring.

Table 4.4        Exceedances of Action and Limit Levels on 10 October 2012


4.2.4                                Exceedances on 11 October 2012

Exceedances of the Action Level in bottom DO were recorded at Stations E9 and S3 only in the 3rd sampling round on 11 October 2012 (Table 4.5).

According to the daily barge operation report, there was preparation work carried out by the Contractor before the burial operation (ie jetting works) resumed at 10:45.  All marine works stopped at approximately 23:00 in the evening.  The actual time of jetting works on 11 Oct 2012 was between 10:45 to 19:30 and 21:00 to 23:00. 

The exceedances of the Action Level at both E9 and S3 in the 3rd sampling round are occasional.  The bottom DO values at these two stations increased and were found to be compliant with the water quality limit in the 4th sampling round when jetting works were still being conducted until 23:00.  In addition, jetting-related oxygen depletion is expected to be caused by the release of suspended solids and its subsequent oxidative process.  However in this case, depth-averaged suspended solids levels at all monitoring stations were low and in compliance with the Action and Limit Levels during all four water sampling rounds.  Therefore the exceedances were unlikely to be caused by the jetting works but should be considered as reflecting natural background fluctuations during the time of monitoring.

Table 4.5        Exceedances of Action and Limit Levels on 11 October 2012

4.2.5                                Exceedances on 13 October 2012

Due to technical problems, impact water quality monitoring in Zone B started around 11:00 on 13 Oct 2012.  As such, a total of three rounds of water sampling were carried out for the day.  Exceedances of the Action and Limit Levels in middle DO, depth-averaged Turbidity and depth-averaged SS were recorded at Stations B3, E9 and F1 in all three sampling rounds (Table 4.6). 

According to the daily barge operation report, there were some preparations works carried out by the Contractor before burial operation on the day.  The burial operation (ie jetting works) was conducted between 10:30 to 12:00 and 13:30 to 16:30 on 13 October 2012. 

As stated above, jetting works were not being undertaken when the exceedance in Depth-averaged Turbidity was recorded at B3 (22:00 - 22:15) in the 3rd round of marine water quality monitoring.  Therefore, the exceedance of the Action Level at B3 is considered as representing natural background fluctuations.

Impact Stations E9 and F1 are located in the north, far away from the cable installation barge.  It should be noted that the average values of depth-averaged Turbidity and depth-averaged SS at E9 (Turbidity = 3.68 NTU; SS = 4.29 mg/L) and F1 (Turbidity = 3.03 NTU; SS = 3.78 mg/L) on 13 October 2012 are actually of the similar magnitudes of their corresponding values (averaged values of 8 – 11 October 2012 for E9: Turbidity = 4.00 NTU, SS =4.61 mg/L; averaged values of 8 – 11 October 2012 for F1: Turbidity = 3.66 NTU, SS = 4.13 mg/L) in the previous dates or even better.  When the sampling was carried out in the first round, the current direction was eastward.  Given the fact that values of all water quality parameters at the Gradient Station (ie G4) and Impact Station (ie E2) in the eastern vicinity of the barge were measured to be within the corresponding Action Levels, the exceedances in middle DO, depth-averaged Turbidity and depth-averaged SS at E9 and F1 in the 1st sampling round, as well as later in the 2nd (18:44 – 19:00 for E9 and 18:03 – 18:17 for F1) and 3rd (19:02 - 19:18 for E9 and 19:44 – 19:59 for F1) rounds when jetting works ceased, were unlikely to be caused by the jetting works but should be considered as representing natural background levels during the time of monitoring.

Table 4.6        Exceedances of Action and Limit Levels on 13 October 2012


4.2.6                                Exceedances on 14 October 2012

Exceedances of the Action and Limit Levels in middle DO, depth-averaged Turbidity and depth-averaged SS were recorded at Stations E9 and F1 in all four sampling rounds on 14 October 2012 (Table 4.7).  According to the daily barge operation report, the burial operation (ie jetting works) was conducted between 10:00 and 16:00 on the day. 

Impact Stations E9 and F1 are located in the north, far away from the cable installation barge.  It should be noted that the average values of depth-averaged Turbidity and depth-averaged SS at E9 (Turbidity = 3.87 NTU; SS = 4.86 mg/L) and F1 (Turbidity = 2.98 NTU; SS =4.00 mg/L) on 13 October 2012 are actually of the similar magnitudes of their corresponding values (averaged values of 8 – 11 October 2012 for E9: Turbidity = 4.00 NTU, SS =4.61 mg/L; averaged values of 8 – 11 October 2012 for F1: Turbidity = 3.66 NTU, SS = 4.13 mg/L) in the previous dates or even better.  Between these two stations and the cable installation barge, there are several Gradient Stations (ie G3 and G4) and Impact Stations (ie E2, E6 and B1), which are located in the middle and therefore more susceptible to the impact of the Project.  But exceedances of Action and Limit Levels in all water quality parameters were recorded at none of these stations.  The fact demonstrates the exceedances in middle DO, depth-averaged Turbidity and depth-averaged SS at the E9 and F1 in the 1st and 2nd sampling rounds, as well as later in the 3rd (15:05 – 19:02) and 4th (19:05 – 23:04) rounds of marine water quality monitoring when jetting works ceased, were unlikely to be caused by the jetting works but should be considered as representing natural background levels during the time of monitoring.

Table 4.7        Exceedances of Action and Limit Levels on 14 October 2012

5                                            Environmental Non-CONFORMANCES

5.1                                      Summary of Environmental Exceedance

Exceedances of the Action and Limit Levels were recorded during the reporting period.  The Event and Action Plan for the identified exceedances were implemented and followed the procedures as stipulated in the EM&A Manual and Table 3.7.  It was concluded that the exceedances were considered to reflect natural background fluctuation rather than to be caused by the Project (See Section 4.2 for details).

5.2                                      Summary of Environmental Non-compliance

No non-compliance events were recorded during the reporting period.

5.3                                      Summary of Environmental Complaint

No complaints were received during the reporting period.

5.4                                      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 Reporting Period

The cable installation works will be conducted in Zone C and from Zone C eastward to the boundary Hong Kong marine waters. 

6.2                                      Monitoring Schedule For The Coming Reporting Period

Impact water quality monitoring will be carried out in Zone C and will cease once the cable installation barge moves out Zone C or no cable laying works are undertaken within Zone C.

7                                            Conclusions

This Weekly Impact Monitoring Report presents the results of impact water quality monitoring undertaken in Zone A and Zone B during the period from 8 October to 14 October 2012 in accordance with the EM&A Manual and the requirements under Environmental Permit (EP - 433/2011).

Water quality of Zone A and Zone B was generally stable throughout the sampling period.  Neither sudden drop in dissolved oxygen concentrations nor sharp increase in turbidity levels and suspended solid levels were observed.  Exceedances of Action and Limit Levels were recorded during the reporting week, but they were considered to reflect natural background fluctuation rather than to be caused by the Project.

It is concluded that no deterioration of water quality was observed and hence the effect of the Project on water quality is considered to be negligible.