Contents
Executive Summary
1.1 Background
1.2 Purpose of the Report
1.3 Structure of the Report
2 Cable Installation Water quality
monitoring
2.1 Monitoring Locations
2.2 Monitoring Parameters and Frequency
2.3 Monitoring Equipment and Methodology
2.4 Baseline Monitoring Results
LIST OF ANNEXES
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Annex A |
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Annex B |
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Annex C |
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Annex D |
LIST OF ANNEXES
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Figure 1.1 |
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Figure 1.2 |
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Figure 2.1 |
EXECUTIVE SUMMARY
ERM-Hong Kong, Limited (ERM) was appointed
by Tata Communications (Bermuda) Ltd to undertake baseline water quality
monitoring (ie for cable installation) prior to the
commencement of construction works for VSNL Intra Asia Submarine Cable System –
Deep Water Bay (Application No. DIR-155/2007).
This Baseline Monitoring
Report has been prepared in compliance with the Further Environmental Permit (FEP-01/294/2007)
and Environmental Monitoring and Audit Manual for VSNL Intra Asia
Submarine Cable System –
Baseline water quality monitoring (ie for cable installation) was conducted between 27
February and 13 March 2009 at six designated monitoring stations near Po Toi Island (ie Zones B to D)
established for the Project. The
monitoring was carried out 3 days per week, at mid-flood and mid-ebb tides, at
three depths (surface, middle and bottom), for 2 weeks prior to the
commencement of construction works.
No major activities were undertaken during baseline monitoring. Water quality monitoring results are,
therefore, representative of the baseline conditions for the Project.
1
introduction
Tata Communications (Bermuda) Ltd (formerly Videsh Sanchar Nigam
Limited (VSNL)) proposes to install a submarine
telecommunications cable, which will run from
In August 2007, a Project Profile (PP)
for the Project 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 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 Environmental Permit to address potential
environmental impacts associated with cable crossings over the HKE’s gas pipeline in southeast
ERM-Hong Kong, Limited (ERM) was appointed
by Tata Communications (Bermuda) Limited as the Monitoring Team (MT) to
implement the part of the EM&A programme (ie
Cable Installation Water Quality Monitoring and Site Inspection) for the
Project.
Given that the water sampling stations in
Zones A and E (Deep Water Bay) are situated quite far away from those in Zones
B to D (Po Toi) and the expected different water
quality characterises, we recommended to present the baseline data in two
separate reports (ie Part A for Deep Water Bay and
Part B for Po Toi) and the corresponding Action and
Limit Levels would be derived from the baseline data for each side (ie Deep Water Bay, Po Toi). Due to rough sea conditions and foggy
weather, the baseline water quality monitoring survey scheduled on 1 March 2009
for the Po Toi side was cancelled due to safety
concerns. As such, the baseline
monitoring for the Po Toi section of works was
delayed and an additional baseline monitoring survey was undertaken on 13 March
2009. The
results of the data obtained from monitoring stations near
The purpose of this Baseline Water Quality Monitoring Report Part B is to determine the
baseline marine water quality at the designated monitoring locations near Po Toi Island (ie
Monitoring Zones B to D) prior to the commencement of the works of
jetting machine operation. These
levels will be used as the basis for assessing environmental impact and
compliance monitoring during the construction (jetting machine operation) of
the Project. This report presents
the monitoring requirements, methodologies and results of the baseline ambient
marine water quality measurements at the monitoring locations in accordance
with the EM&A Manual.
The structure of the report is as follows:
Section
1 : Introduction
Details the background, purpose and structure of the
report.
Section
2 : Water
Quality Monitoring
Summarises the water quality
monitoring parameters, monitoring programmes, monitoring methodologies,
monitoring frequency, monitoring locations, monitoring results and establishes
the Action and Limit Levels in accordance with the EM&A Manual.
Section
3 : Conclusions
Concludes the
representativeness of the baseline monitoring results and observations for the
Project.
2
Cable Installation Water
quality monitoring
The following Section
provides details of the baseline monitoring of water quality prior to the
installation of the submarine cable.
In accordance with the EM&A Manual, prior to the installation
of the cable, water quality sampling was undertaken at monitoring stations near
Po Toi Island (ie Zones B
to D). The locations of the
sampling stations are shown in Figure 2.1.
·
C1,
C2 and C3 are located approximately 600 m north of the cable alignment at Po Toi for monitoring the effect of cable laying works on
coral communities in the area;
·
F1 is
used to monitor the effect of the cable installation works on the Po Toi Fish Culture Zone (FCZ); and
·
R2 and
R3 are Control Stations for C1, C2, C3 and F1 at Po Toi
which are not supposed to be influenced by the cable laying works due to their
remoteness to the construction works.
The
suggested co-ordinates of Zones B to D as well as the above monitoring stations
are listed in Table 2.1 and Table 2.2, respectively.
Table 2.1 Co-ordinates
of Starting Points and Ending Points for Zones B to D (HK Grid)
|
Zone |
Starting
Point |
Ending
Point |
||
|
|
Easting |
Northing |
Easting |
Northing |
|
B |
841917.597 |
802680.115 |
844161.823 |
801308.268 |
|
C |
844161.823 |
801308.268 |
845555.155 |
801495.491 |
|
D |
845555.155 |
801495.491 |
846970.152 |
801749.210 |
Table 2.2 Co-ordinates
of Baseline Monitoring Stations (HK Grid)
|
Station |
Nature |
Corresponding Control Station |
Easting
|
Northing |
|
C1 |
Coral
Colonies |
R2,
R3 |
843547.181 |
802010.004 |
|
C2
(a) |
Coral
Colonies |
R2,
R3 |
844800 |
801840 |
|
C3 |
Coral
Colonies |
R2,
R3 |
846179.538 |
802224.554 |
|
F1 (b) |
Fish Culture Zone |
R2, R3 |
843920 |
802730 |
|
R2 |
Control
Station |
- |
842074.745 |
803375.183 |
|
R3 (c) |
Control
Station |
- |
846444 |
804982 |
|
Notes: (a) The
original location of C2 was situated very close to the shore. C2 is therefore moved 80 m seaward
from the original location due to safety reasons and the new location is
considered representative. (b) The
original location of F1 was situated very close to the shore. F1 is therefore moved 40 m seaward from
the original location due to safety reasons and the new location is
considered representative. (c) The original location of
R3 was situated approximately 1500 m off the east coast of Island. In view of frequent rough sea
conditions in that area and the subsequent safety concerns, R3 is moved close to the midpoint of Po Toi Island and Sung Kong. Given that R3 is a
control station, its new location is considered
representative. |
||||
2.2
Monitoring
Parameters and Frequency
The
baseline water quality monitoring was conducted in accordance with the
requirements stated in the EM&A Manual, which are
presented below.
2.2.1
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.
2.2.2
Monitoring Frequency
Baseline water quality
monitoring was carried out for two weeks, with the frequency of three days per
week. The interval between two sets
of monitoring was not less than 36 hours.
The monitoring was undertaken at six locations (four impact monitoring
stations C1, C2, C3, F1 and two control monitoring stations R2 and R3), as shown in Figure
2.1. Samples were taken during
mid-flood and mid-ebb tidal state on each sampling occasion.
2.3
Monitoring
Equipment and Methodology
2.3.1
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 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.
2.3.2
Monitoring Methodology
Timing & Frequency
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 be less than 0.5m for capturing representative
tides.
Reference were 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
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. For stations that were less than 3 m in
depth, only the mid depth sample was taken.
Protocols
The multi-parameter measuring instrument (YSI 6820) was checked and
calibrated by an HOKLAS accredited laboratory before use (see calibration
reports in Annex B). 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 an 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 to the client 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 (details refer to Annex C).
2.4
Baseline
Monitoring Results
The monitoring data and graphical
presentations are summarised in Annex
D. No major activities
influencing the water quality were identified during the monitoring period.
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 Level of Water Quality
|
Parameter |
Action Level |
Limit Level |
|
DO in mgL-1 (b) |
Surface and Mid-depth 5%-ile of baseline data for surface and middle layer Bottom 5%-ile of baseline
data for bottom layers |
Surface and Mid-depth 4mg/L or 1%-ile of baseline for surface and middle layer Bottom 2mg/L or 1%-ile of
baseline data for bottom layer |
|
SS in mgL-1 (Depth-averaged (a)) (c) |
95%-ile
of baseline data, or 20%
exceedance of value at any impact station compared
with corresponding data from control stations |
99%-ile
of baseline data, or 30% exceedance
of value at any impact station compared with corresponding data from control
stations |
|
Turbidity in NTU (Depth-averaged (a)) (c) |
95%-ile
of baseline data, or 20%
exceedance of value at any impact station compared
with corresponding data from control stations |
99%-ile
of baseline data, or 30%
exceedance of value at any impact station compared
with corresponding data from control stations |
|
Notes: a. “Depth-averaged”
is calculated by taking the arithmetic means of reading of all three depths. b. For
DO, non-compliance of the water quality limits occurs when monitoring result
is lower than the Action/Limit Levels. c. For
SS and turbidity, non-compliance of the water quality limits occurs when
monitoring result is higher than the Action/Limit Levels. |
||
The Action and Limit Levels of DO and
turbidity are derived from the baseline monitoring data for all impact stations
for Zones B to D (including Stations F1, C1, C2 and C3), and the results are
presented in Table 2.4. Two sets of the Action and Limit levels
of suspended solids are established for two groups of impact monitoring
station(s) in the area, namely F1 to monitor the FCZ and C1, C2 as well as C3
to monitor the coral communities (see Tables
2.5 and 2.6).
Please note that the results of Part B Baseline Monitoring are used to
determine the Action and Limit Levels for the works to be undertaken near Po Toi Island (ie Zones B to D).