Contents

Executive Summary                                                             

1                      INtroduction                                                                          

1.1                   Background                                                                           

1.2                   Purpose of this Report                                                    

1.3                   Structure of the Report                                                

2                      Water Quality Update Monitoring                              

2.1                   Monitoring Location                                                          

2.2                   Sampling and Testing Methodology                          

2.3                   Baseline Update Monitoring Results                       

2.4                   Action and Limit Levels                                                     

3                      conclusion                                                                             

 

ANNEXES

Annex A          Baseline Water Quality Update Monitoring Schedule (Zone A)

Annex B          Calibration Reports of Multi-parameter Sensor

Annex C          QA/ QC Results for Suspended Solids Testing

Annex D          Baseline Water Quality Update Monitoring Results (Zone A)

 

EXECUTIVE SUMMARY

Baseline Water Quality Update Monitoring

Baseline water quality update monitoring was conducted between 5 November and 9 November 2013 at 11 designated monitoring stations (7 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 hours before and 2 hours after mid flood and mid-ebb tides.  The tidal range selected for the baseline update 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 update monitoring.  Water quality update monitoring results are, therefore, considered to be representative for the baseline conditions of the areas where Project marine installation works will be undertaken.

In accordance with the EM&A Manual, the baseline update 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 Project marine installation works.  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

(7.01 mg L-1), or

99%-ile of baseline data

(7.15 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

(5.91 mg L-1)

Surface and Middle(d)

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

(5.85 mg L-1)

Bottom

5%-ile of baseline data for bottom layers

(5.72 mg L-1)

Bottom

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

(5.62 mg L-1)

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

95%-ile of baseline data

(5.09 NTU), or

99%-ile of baseline data

(5.25 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 landing site is at a new Beach Manhole (BMH) and ultimately is connected with a Data Centre in Tseung Kwan O (TKO) Industrial Estate which was completed 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 extends westward 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 and enters the South China Sea.  The total length of cable in Hong Kong SAR waters is approximately 33.5 km.  A map of the 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).  EPD 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 (EM&A Manual) is required for this Project.  Baseline data were collected prior to the start of cable installation works in 2012 and EM&A was conducted throughout the cable installation and after its completion in early 2013 as required in the EM&A Manual. 

Upon inspection in October 2013 the ASE cable was found to be damaged and a section within Zone A (see Figure 2.1) requires re-installation.  The EM&A programme is therefore required to resume for the cable installation works in Hong Kong Waters (the “Project”). 

In accordance with the EM&A Manual, baseline monitoring of marine water quality should be undertaken for the Project.  The baseline water quality monitoring was conducted prior to the cable installation works in 2012.  An update to the baseline water quality has now been conducted to reflect the current baseline water quality conditions prior to the cable re-installation works.  This Baseline Water Quality Monitoring Update Report (Zone A) (“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 update monitoring for the Project. 

1.2                                   Action and Limit Levels have been derived from the baseline water quality update monitoring data for Zone A. Purpose of this Report

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

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

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 Update Monitoring

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

Section 3: Conclusion

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

2                                          Water Quality Update Monitoring

2.1                                   Monitoring Location

Baseline water quality update monitoring in Zone A was conducted prior to the commencement of Project marine installation works at the monitoring stations listed in Table 2.1 and shown in Figure 2.1.

·      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 Project marine installation 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 Project marine installation 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 Project marine installation works due to its remoteness from the works.

 

Table 2.1        Water Quality Update Monitoring Stations

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

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 update monitoring.

Table 2.2        Equipment used during Baseline Water Quality Update Monitoring

Equipment

Model

Global Positioning Device

Garmin eTrex 10

Water Depth Gauge

Speedtech Instrument SM-5

Water Sampling Equipment

1520 Kemmerer Water Sampler

Salinity, DO, Temperature Measuring Meter

YSI Pro 2030

Current Velocity and Direction

Flow Probe FP111

Turbidity Meter

HACH Model 2100Q Turbid Meter

 

2.2.3                           Monitoring Frequency and Timing

The water quality update 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 hours before and 2 hours after mid flood and mid-ebb tides.  The tidal range selected for the baseline update 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 update monitoring was conducted between 5 November and 9 November 2013, following the schedule presented in Annex A.  Schedule for baseline update 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 will be 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.

2 replicate samples were collected from each of the monitoring events for in situ measurement and lab analysis[YL1] .[FZ2] 

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[YL3] . [FZ4] 

2.3                                   Baseline Update Monitoring Results

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

The observations from the update monitoring results are as following:

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

·      Dissolved Oxygen (DO) levels were recorded to stay at a similar level across all the monitoring stations within the baseline update monitoring period;

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

·      Minor variations of Turbidity and SS levels were observed within the baseline update monitoring period whilst Turbidity and SS levels moved to a similar level across all the monitoring stations in the last day of monitoring;

·      On 5 November 2013, relatively higher levels of Turbidity were recorded at Control Station C1, Gradient Station G2, Impact Station S2 and S3 at mid-ebb tidal stage and were observed at Impact Station E7 and F1 at mid-flood tidal stage;

·      On 5 November 2013, relatively higher levels of SS were detected at Control Station C1 at mid-ebb tidal stage and were also recorded at Impact Station E7 at mid-flood tidal stage; and,

·      The above sporadic patterns of relatively high levels of Turbidity and SS in 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.

 

Action and Limit Levels have been determined based on baseline water quality update monitoring data for all monitoring stations in Zone A.  The results are presented in Table 2.4.  Please note that the results are used to determine the Action and Limit Levels for the Project marine installation works to be undertaken in Zone A[FZ5] [YL6] .

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

(7.01 mg L-1), or

99%-ile of baseline data

(7.15 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

(5.91 mg L-1)

Surface and Middle(d)

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

(5.85 mg L-1)

Bottom

5%-ile of baseline data for bottom layers

(5.72 mg L-1)

Bottom

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

(5.62 mg L-1)

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

95%-ile of baseline data

(5.09 NTU), or

99%-ile of baseline data

(5.25 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 update monitoring in Zone A was conducted between 5 November and 9 November 2013 at 11 designated monitoring stations (including 7 Sensitive Receiver Stations, 3 Gradient Stations and 1 Control Station).  The update monitoring was carried out over 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 update monitoring results are, therefore, considered to be representative of the current baseline conditions of the areas where marine installation works will be undertaken for the Project.

The baseline update 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 A throughout the Project marine installation works.

 



([1])        Hong Kong Observatory (2013) http://www.hko.gov.hk/tide/eQUBtide.htm [Accessed in November 2013]


 [YL1]Amended.  We have only 2 replicate samples

 [FZ2]Or duplicate a implied below.

 [YL3]Yes.  At each water depth at each station, 2 replicate reading were made.

 [FZ4]Duplicate to x3 as implied above? 

 [FZ5]Repetitive?

 [YL6]It is not repetitive.  This is the first time we say that we will used baseline monitoring results to determine Action and Limit Levels in the main text.  We did mention once in the Introduction