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).
This is the
Third 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 10 December 2012 to 16 December 2012.
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
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 in parallel
with the submarine cable laying works in Zone A and Zone B, and temporarily ceased after 16 October 2012 as the cable
installation barge moved outside Zone C. During this reporting week, the post-installation
works that involved hand jetting were conducted in Zone A and Zone B. This Report therefore presents
the monitoring results from the monitoring stations within Zone A and Zone B.
During
the reporting period from 10
December 2012 to 16 December 2012, post-installation
works that involved hand jetting by diver were conducted in Zone A and Zone B.
A
summary of the relevant permits, licences and reports on marine water quality
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
|
|
First Weekly Impact Water Quality Monitoring
Report
|
|
Throughout
the construction stage
|
Submitted on 19 October 2012
|
|
Second Weekly Impact Water Quality Monitoring
Report
|
|
Throughout
the construction stage
|
Submitted on 24 October 2012
|
3
Impact Water Quality Monitoring
Requirements
In accordance with the EM&A Manual, water quality samplings
were collected at the stations situated around the cable laying works in
Zone A and Zone B when post-installation
works involving hand jetting were conducted in these zones. 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
|
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
|
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.
3.3.1
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 diver jetting works from 7:00 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 diver
jetting for cable post-installation works was undertaken in Zone A. The daily sampling works ceased once the diver
jetting works in Zone A were completed.
Similarly,
impact monitoring at C2, G3, G4, G7, B1, B2, B3, E1, E2, E6, E9 and F1 commenced
when the diver jetting for cable post-installation works was undertaken in Zone
B. The daily sampling works ceased
once the diver jetting works in Zone B were completed.
Due to the weather
conditions and travelling time between stations, in-situ and SS measurements were taken at the impact monitoring
stations with an 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 a 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 a 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 Zone 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 of
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 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 two monitoring events were
scheduled in the reporting period between 10
December 2012 and 15 December 2012 (Annex
A). Monitoring events at all designated
monitoring stations within Zone A and Zone B were performed on schedule. No major activities influencing the
water quality were identified during the 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. 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
|
Date
|
Surface
DO
|
Middle
DO
|
Bottom
DO
|
Depth-averaged
Turbidity
|
Depth-averaged
SS
|
|
|
Exceedances
|
|
|
Action Level
|
Limit Level
|
Action Level
|
Limit Level
|
Action Level
|
Limit Level
|
Action Level
|
Limit Level
|
Action Level
|
Limit Level
|
|
10/12
|
|
|
|
|
|
|
|
|
E7, E8, E9, F1, S1, S2,
S3
|
|
|
15/12
|
|
|
|
|
|
|
|
|
E9
|
E9
|
4.2.1
Exceedances
on 10 December 2012
Exceedances
of the Action Level in depth-averaged SS were recorded at Impact Station E7,
E8, E9, F1, S1, S2 and S3 in the 1st, 2nd, 3rd
and 4th sampling rounds on 10 December 2012 (Table 4.2).
According
to the daily barge operation report, there was preparation and equipment
maintenance works carried out by the Contractor before the burial operation by
diver (ie hand jetting works) resumed at 13:00. All marine works stopped at
approximately 19:30 in the evening. The actual time of hand jetting works on
10 Dec 2012 was between 13:00 to 19:30. This period overlapped with the marine
water quality monitoring.
Hand
jetting works for the Project did not start when the exceedances were recorded
at all monitoring stations (i.e. C1, G1, G2, G3, E8, S1, E7, F1, E9, S2 and S3)
in the 1st round (07:00 – 10:50) of marine water quality monitoring. Therefore,
the exceedances of the Action Level at in the 1st sampling round are
considered as representing natural background fluctuations rather than a result
of the cable installation (hand jetting) works.
For
the exceedances in the 2nd and 3rd rounds of water quality sampling, considering
the generally elevated Depth-averaged SS levels compared with the baseline data
at all monitoring stations including the Control Station C1 to the east of Lei
Yun Mun, it is unlikely that the localised and small
scaled diver burial activities (hand jetting only) can cause SS elevation of
such scale. Attention should also be given to the fact that such exceedances at
all sampling stations occurred at the 1st round of water quality sampling
before the hand jetting works started. It is hence considered that the
Depth-averaged SS exceedances at the 2nd and 3rd rounds of sampling
may represent a natural and sporadic phenomenon, which is not related to the
diver burial operation of the Project.
Given the discussion as
above, the exceedances of the Action Level at all impact stations in the 4th
round of sampling (19:34 – 23:06) when the burial works ended at 19:30 are
unlikely to be caused by the Project either. Rather, the exceedances are considered
to be a continuum of the performance of the natural background conditions for
the day.
Table 4.2 Exceedances
of Action Level on 10
December 2012
|
Date
|
10
December 2012 (Measured)
11
December 2012 (In situ results
received by ERM)
13
December 2012 (Laboratory results received by ERM)
|
|
Monitoring
Station
|
E8, S1,
E7, F1, E9, S2 and S3
|
|
Parameter(s)
with Exceedance(s)
|
Depth-averaged
SS (mg/L)
|
|
Action
Levels
|
6.27
mg/L, or 20% exceedance of value at any impact
station compared with corresponding data from control station
|
|
Limit
Levels
|
6.40
mg/L, and 30% exceedance of value at any impact
station compared with corresponding data from control station
|
|
Measured
Levels at Impact Stations Where Exceedances Were Recorded
|
1st Round
|
SS: E8=6.95 mg/L; S1=7.25 mg/L; E7=7.00 mg/L,
F1=7.98 mg/L; E9=7.30 mg/L; S2= 6.70 mg/L; and S3=7.33 mg/L
|
|
2nd Round
|
SS: E8=7.07 mg/L; S1=7.15 mg/L; E7=7.05 mg/L,
F1=7.77 mg/L; E9=7.30 mg/L; S2= 6.90 mg/L; and S3=7.30 mg/L
|
|
3rd Round
|
SS: E8=7.00 mg/L; S1=7.20 mg/L; E7=6.98 mg/L,
F1=7.57 mg/L; E9=7.52 mg/L; S2= 6.67 mg/L; and S3=7.12 mg/L
|
|
4th
Round
|
SS: E8=6.87 mg/L; S1=7.17 mg/L; E7=7.15 mg/L,
F1=7.63 mg/L; E9=7.15 mg/L; S2= 6.78 mg/L; and S3=7.43 mg/L
|
|
Exceedances
|
1st
Round
|
Exceedance of Action Level in SS: E8, S1,
E7, F1, E9, S2 and S3.
|
|
2nd
Round
|
Exceedance of Action Level in SS: E8, S1,
E7, F1, E9, S2 and S3.
|
|
3rd
Round
|
Exceedance of Action Level in SS: E8, S1,
E7, F1, E9, S2 and S3.
|
|
4th
Round
|
Exceedance of Action Level in SS: E8, S1,
E7, F1, E9, S2 and S3.
|
4.2.2
Exceedances
on 15 December 2012
Exceedances of Action and
Limit Levels in depth-averaged Turbidity and depth-averaged SS were recorded at
StationsE9 in all four sampling rounds on 15 December 2012 (Table 4.3).
According to the daily
barge operation report, there were some maintenance
works carried out by the Contractor before burial operation. The burial operation (ie jetting works) was conducted between 13:00 and 17:00 on
15 December 2012 and this period overlapped with the marine water quality
monitoring.
Hand jetting
works for the Project did not start when the exceedances in depth-averaged
Turbidity and depth-averaged SS were recorded at E9 in the 1st round
(07:00 – 11:02) of marine water quality monitoring. Therefore, the exceedances of the Action
and Limit Levels at in the 1st sampling round are considered as
representing natural background fluctuations rather than a result of the cable
installation (hand jetting) works.
For the
exceedances in depth-averaged Turbidity and depth-averaged SS in the 2nd
and 3rd sampling rounds, Impact Stations E9 is located in the north,
far away from the cable installation barge. Between this station and the cable
installation barge, there were several gradient stations (ie
G3 and G4) and impact stations (ie E6, B1 and E2),
which are located in the middle and therefore more susceptible to the impact of
the project. But exceedances of
Action or Limit Levels in all water quality parameters were recorded at none of
these stations. The fact
demonstrates the exceedances in depth-averaged Turbidity and depth-averaged SS
at E9 in these two sampling rounds, as well as later in the 4th (19:02 – 22:53)
round of marine water quality monitoring when hand jetting works ceased for the
day, 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 15 December 2012
|
Date
|
15 December 2012 (Measured)
17 December 2012 (In situ results received
by ERM)
19 December 2012 (Laboratory results
received by ERM)
20 December 2012 (Records of Contractor’s
activities on monitoring day received by ERM)
|
|
Monitoring
Station
|
B1, B2, B3, E1, E2, E6, E9, and F1
|
|
Parameter(s)
with Exceedance(s)
|
Depth-averaged
Turbidity (NTU)
|
Depth-averaged
SS (mg/L)
|
|
Action
Levels
|
3.01 NTU
or 20% exceedance of data at control station
|
4.09
(mg/L) or 20% exceedance of data at control station
|
|
Limit
Levels
|
3.13 NTU
and 30% exceedance of data at control station
|
4.60
(mg/L) and 30% exceedance of data at control
station
|
|
Measured
Levels at Impact Stations Where Exceedances Were Recorded
|
1st
Round
|
Turbidity: E9=3.44 NTU.
SS: E9=4.00 mg/L.
|
|
2nd
Round
|
Turbidity: E9=2.88 NTU.
SS: E9=3.35 mg/L.
|
|
3rd
Round
|
Turbidity: E9=3.47 NTU.
SS: E9=3.92 mg/L.
|
|
4th
Round
|
Turbidity: E9=3.42 NTU.
SS: E9=3.90 mg/L.
|
|
Exceedances
|
1st
Round
|
Exceedance of Action and Limit Levels in Turbidity: E9;
Exceedance of Action Level in SS: E9.
|
|
2nd
Round
|
Exceedance of Action Level in Turbidity: E9;
Exceedance of Action Level in SS: E9.
|
|
3rd
Round
|
Exceedance of Action and Limit Levels in Turbidity: E9;
Exceedance of Action Level in SS: E9.
|
|
4th
Round
|
Exceedance of Action and Limit Levels in Turbidity: E9;
Exceedance of Action Level in SS: E9.
|
|
|
|
|
5
Environmental Non-CONFORMANCES
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 the
impact 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.
No complaints were received
during the reporting period.
No summons or prosecution
on environmental matters were received during the reporting period.
6
Future Key Issues
In
the week of 24 December 2012, there are protection works to be conducted at the
crossing point of Drainage
Services Department (DSD) sewage pipe and the submarine cable in
Zone A.
Impact water quality monitoring
will be carried out in parallel with the diver jetting for the projection works at
the crossing point of DSD
sewage pipe and the submarine cable in Zone A in the
week of 24 December 2012.
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 10 December 2012 to 16 December 2012 in accordance with the EM&A Manual and the requirements
under Environmental Permit (EP - 433/2011).
Water quality in 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 are
considered to reflect natural background fluctuation rather than impact caused
by the Project.
It is concluded that no
deterioration of water quality was observed and hence the impact of the Project
on water quality is considered to be negligible.
