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 Fourth 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 24 December 2012 to 30 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 (if any).
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.
During this reporting week,
the post-installation works that involved hand jetting were conducted in Zone
A. This Report therefore
presents the monitoring results from the monitoring stations within Zone A.
During the reporting period
from 24 December
2012 to 30 December 2012,
post-installation works that involved hand jetting by diver were conducted in
Zone A.
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
|
|
Third Weekly Impact Water Quality Monitoring Report
|
|
Throughout
the construction stage
|
Submitted on 24 December 2012
|
3
Impact
Water Quality Monitoring Requirements
In accordance with the EM&A Manual, marine water samples were collected at the stations
situated around the submarine-cable
protection works at the crossing point with DSD sewage pipe in Zone A. Hand
jetting was involved in the protection
works. 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 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
3.2 summaries the
equipment used for the impact water quality monitoring.
Table 3.2 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.
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. The monitoring frequency
and parameters for Impact Monitoring are summarised in Table 3.3.
Table
3.3 Monitoring
Frequency and Parameters for Impact Monitoring in Zone A
|
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,
|
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
3.4.
Table 3.4 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.
|
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 3.5.
Table 3.5 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 three monitoring events were scheduled
in the reporting period between 24 December 2012
and 30 December 2012 (Annex A). Monitoring events at all designated
monitoring stations within Zone A 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 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 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
|
|
27/12
|
|
|
|
|
|
|
|
|
E7, E8, E9, F1, S1, S2,
S3
|
|
|
28/12
|
|
|
|
|
|
|
|
|
E7, E8, E9, F1, S1, S2,
S3
|
|
|
29/12
|
|
|
|
|
|
|
|
|
E7, E8, E9, F1, S1, S2,
S3
|
|
4.2.1
Exceedances
on 27
December 2012
Exceedances of the Action Level in
depth-averaged SS were recorded at Impact Stations E7, E8, E9, F1, S1, S2 and
S3 in the 1st, 2nd, 3rd and 4th sampling
rounds on 27 December 2012 (Table 4.2).
According to the daily barge
operation report, there was preparation and equipment setting up works carried
out by the Contractor before the hand jetting works, which commenced at
14:00. The water jetting works
stopped at approximately 16:00 due to strong current. The actual time of hand jetting works on
27 December 2012 was between 14:00 to 16:00. 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 the result of the cable protection
(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 hand jetting (a total of only 13 m cable buried) 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 phenomenon and
overall elevation in the background Depth-averaged SS level, 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 (19:10 – 23:06) 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 27
December 2012
|
Date
|
27
December 2012 (Measured)
31
December 2012 (In situ results
received by ERM)
2 January
2013 (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=6.92 mg/L; S1=7.02 mg/L; E7=6.90 mg/L,
F1=7.38 mg/L; E9=7.30 mg/L; S2= 6.92 mg/L; and S3=7.40 mg/L
|
|
2nd
Round
|
SS: E8=6.93 mg/L; S1=7.15 mg/L; E7=7.03 mg/L, F1=7.17
mg/L; E9=7.02 mg/L; S2= 6.87 mg/L; and S3=7.25 mg/L
|
|
3rd
Round
|
SS: E8=6.82 mg/L; S1=6.85 mg/L; E7=6.92 mg/L,
F1=7.13 mg/L; E9=7.12 mg/L; S2= 6.95 mg/L; and S3=7.42 mg/L
|
|
4th
Round
|
SS: E8=6.78 mg/L; S1=7.00 mg/L; E7=7.02 mg/L,
F1=7.03 mg/L; E9=7.08 mg/L; S2= 6.87 mg/L; and S3=7.27 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 28 December 2012
Exceedances of the Action Level in depth-averaged
SS were recorded at Impact Stations E7, E8, E9, F1, S1, S2 and S3 in the 1st,
2nd, 3rd and 4th sampling rounds on 28
December 2012 (Table 4.3).
According
to the daily barge operation report of 28 December 2012, there was preparation
and equipment setting up works carried out by the Contractor before the hand
jetting works, which commenced at 10:30.
The water jetting works stopped at approximately 19:00 for the day. The actual time of hand jetting works on
28 December 2012 was between 10:30 to 19:00. 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, E7, F1, E9,
S1 and S2) except S3 in the 1st round (07:00 – 10:21) of marine
water quality monitoring.
Therefore, the exceedances of the Action Level
at these stations in the 1st sampling round are considered as
representing natural background fluctuations rather than a result of the cable
protection (hand jetting) works.
For the exceedances at impact station S3 in the 1st
round of water quality sampling and all monitoring stations in the 2nd
and 3rd rounds, 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 hand jetting (a total of only 42 m
cable buried) can cause SS elevation of such scale. Attention should also be given to the
fact that such exceedances at all sampling stations
(except S3) 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 phenomenon and overall elevation in the background Depth-averaged SS
level, 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 (19:10 –
23:04) 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
4.3 Exceedances of Action and Limit Levels on 28 December 2012
|
Date
|
28
December 2012 (Measured)
31
December 2012 (In situ results
received by ERM)
2 January
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=6.87 mg/L; E7=7.03 mg/L,
F1=6.97 mg/L; E9=7.10 mg/L; S2= 6.95 mg/L; and S3=6.85 mg/L
|
|
2nd
Round
|
SS: E8=7.07 mg/L; S1=7.12 mg/L; E7=6.88 mg/L,
F1=6.93 mg/L; E9=7.02 mg/L; S2= 6.95 mg/L; and S3=7.07 mg/L
|
|
3rd
Round
|
SS: E8=7.02 mg/L; S1=6.70 mg/L; E7=7.00 mg/L, F1=7.03
mg/L; E9=7.03 mg/L; S2= 6.97 mg/L; and S3=6.98 mg/L
|
|
4th
Round
|
SS: E8=6.92 mg/L; S1=6.90 mg/L; E7=6.82 mg/L,
F1=6.87 mg/L; E9=6.93 mg/L; S2= 7.07 mg/L; and S3=6.95 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.
|
4.2.3
Exceedances
on 29 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 29 December 2012 (Table
4.4).
According
to the daily barge operation report of 29 December 2012, there was preparation
and equipment setting up works carried out by the Contractor before the hand
jetting works, which commenced at 10:30.
The water jetting works stopped at approximately 19:00 for the day. The actual time of hand jetting works on
29 December 2012 was between 10:30 to 19:00. 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, E7, F1, E9, S1
and S2) except S3 in the 1st round (07:00 – 10:22) of marine water
quality monitoring. Therefore, the exceedances of the Action Level at these stations in the 1st
sampling round are considered as representing natural background fluctuations
rather than a result of the cable protection (hand jetting) works.
For the exceedances
at impact station S3 in the 1st round of water quality sampling and
all monitoring stations in the 2nd and 3rd rounds,
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 hand jetting (a total of only 64 m cable buried) can
cause SS elevation of such scale.
Attention should also be given to the fact that such exceedances
at all sampling stations (except S3) 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 phenomenon and
overall elevation in the background Depth-averaged SS level, 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 (19:08 – 22:55) 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 4.4 Exceedances of Action and Limit Levels on 29 December 2012
|
Date
|
29
December 2012 (Measured)
2
January 2013 (In situ results received by ERM)
2 January
2013 (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=7.25 mg/L; S1=7.08 mg/L; E7=7.02 mg/L,
F1=7.12 mg/L; E9=6.98 mg/L; S2= 6.92 mg/L; and S3=6.97 mg/L
|
|
2nd
Round
|
SS: E8=6.98 mg/L; S1=7.05 mg/L; E7=7.13 mg/L, F1=6.87
mg/L; E9=7.03 mg/L; S2= 6.98 mg/L; and S3=7.00 mg/L
|
|
3rd
Round
|
SS: E8=7.13 mg/L; S1=6.92 mg/L; E7=6.98 mg/L,
F1=7.38 mg/L; E9=7.23 mg/L; S2= 7.10 mg/L; and S3=7.02 mg/L
|
|
4th
Round
|
SS: E8=7.13 mg/L; S1=7.10 mg/L; E7=6.98 mg/L,
F1=7.05 mg/L; E9=7.10 mg/L; S2= 7.13 mg/L; and S3=7.18 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.
|
5
Environmental
Non-CONFORMANCES
Exceedances of the Action Level 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 3.4.
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
By the end of
this reporting week, submarine-cable installation and post-installation works,
in which jetting works are involved, have been completed. Given the completion
of the marine construction phase involving jetting works of this project, no
jetting works of any types are expected to be carried out except for any
accidence in the future that requires the said task.
Since no jetting
works are anticipated for the Project, impact water quality monitoring would
not be required henceforth if no accidence.
7
Conclusions
This Weekly Impact Monitoring Report
presents the results of impact water quality monitoring undertaken in Zone A during
the period from 24 December
2012 to 30 December 2012 in accordance with the EM&A Manual and the requirements
under Environmental Permit (EP - 433/2011).
Water quality in Zone A 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 Level 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.
By the end of
this reporting week, submarine-cable installation and post-installation works,
in which jetting works are involved, have been completed. Since no jetting
works are anticipated for the Project in future, impact water quality
monitoring would not be required henceforth if no accidence.
