_files/image002.jpg)
_files/image004.jpg)
_files/image006.jpg)
Contents
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
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)
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
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
·
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
·
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.