1.1 Purpose of the
Report
1.2 Structure of the
Report
2.1 Background
2.2 Marine
Construction Works Undertaken during Reporting Week
2.3 Status of
Environmental Approval Documents
3 Water Quality Monitoring
Requirements
3.1 Monitoring
Locations
3.2 Monitoring
Parameters and Frequency
3.3 Monitoring
Equipment and Methodology
4.1 Data Collected
During Mid-Ebb and/or Mid-Flood Tidal Conditions
4.2 Continuous
In-Situ Measurement Data
5 Environmental
Non-CONFORMANCES
5.1 Summary of
Environmental Exceedance
5.2 Summary of
Environmental Complaint
5.3 Summary of
Environmental Summons and Prosecution
6.1 Key Issues For
The Coming Week
6.2 Monitoring
Schedule For The Coming WEEK
LIST
OF TABLES
Table
2.1 Summary of Marine Works Undertaken During
the Reporting Week
Table 2.2 Summary of Environmental Licensing,
Notification, Permit and Reporting Status
Table.3.1 Co-ordinates of Starting Points and Ending
Points for Zone A (HK Grid)
Table 3.2 Co-ordinates of All Monitoring Stations in
Zone A (HK Grid)
Table 3.3 Monitoring Frequency and Parameters for
Impact Monitoring
Table 3.4 Action and Limit Levels of Water Quality
for Zone A
Table 3.5 Event Action Plan for Water Quality
Table 4.1 Summary of Exceedances occurring during
the Reporting Week
LIST
OF FIGURES
Figure
2.1 The
Route of the Proposed Cable System
LIST
OF ANNEXES
|
Annex
A |
|
|
Annex
B |
|
|
Annex
C |
|
|
Annex
D |
The construction works for
the VSNL Intra Asia Submarine Cable System –
Summary of Construction Works
undertaken during the Reporting Period
During
the reporting period, cable repair works continued in Zone A and were completed
on 11 August 2009. Following this,
the cable repair barge “Challenger 1” demobilised on 12 August 2009.
Water Quality
For the impact monitoring, four monitoring events
were scheduled between 7 August and 13
August 2009.
Monitoring events at all designated monitoring stations were performed
on schedule, ie four events took place on 7 August, 8 August, 10 August and 11
August.
Environmental Non-conformance
There were daily exceedances of Action and Limit
Levels for dissolved oxygen, both bottom layer (on all days) and depth-averaged
(also on all days). There were
daily exceedances of suspended solids with the exception of 7 August 2009 Such exceedances were recorded at only
one station of the four, except during the mid-flood tide on 10 August when
they were recorded at three stations.
Depth-averaged turbidity was compliant with Action and Limit levels
throughout the reporting period, with the exception of one Action Level
exceedance at Station S1 on 8 August.
Results of detailed investigations have indicated that with the
exception of one exceedance (Suspended Solids (SS) at B1 on 11 August 2009
during mid-flood tide) none of the mentioned exceedances were attributed to the
Project construction works. The
exceedance of SS at B1 on 11 August 2009 during mid-flood tide was considered
potentially to be due to the Project works but further investigation was not
possible since at the time of receiving the SS analysis results (17 August
2009) the cable repair barge had already demobilised (on 12 August 2009).
No complaints were received during the reporting week.
No environmental
summons/prosecution were received during the reporting week.
Future Key Issues
Repair of the cable has now been completed and as
there will be no cable installation works in the following weeks, the impact
monitoring will be suspended until the resumption of the marine works.
ERM-Hong Kong, Limited (ERM) was appointed
by Tata Communications (Bermuda) Ltd (formerly Videsh Sanchar
Nigam Limited (VSNL)) as the Monitoring Team (MT) to implement
the Environmental Monitoring and Audit (EM&A) programme for the VSNL Intra
Asia Submarine Cable System –
This is the eighth Weekly Impact
Monitoring Report, which
summarises the impact monitoring results and audit findings for the EM&A
programme during the reporting period from 7 August to 13 August 2009.
The structure of the report is as follows:
Section 1 : Introduction
Details the background,
purpose and structure of the report.
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
Plans.
Section 4 : Impact Monitoring
Results
Summarises the monitoring
results obtained in the reporting period.
Section 5 : Environmental Non-conformance
Summarises any monitoring exceedances, environmental complaints and
environmental summons within the reporting period.
Section 6 : Future Key Issues
Summarises
the monitoring schedule for the next week.
Section 7 : Conclusions
Presents the key findings of
the impact monitoring results.
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) 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 an 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 the Environmental Permit to address
potential environmental impacts associated with cable crossings over the HKE’s
gas pipeline in southeast
Baseline
Monitoring was conducted near
Impact
Monitoring has been carried out at
A cable fault was then identified in the previously
laid submarine telecommunications cable in Zone A. Hence, the marine works of this Project
were resumed on 24 July 2009 to locate the cable fault and replace the
cable. This report presents
results of the data from monitoring stations in Zone A for the final stage of
cable repair works. Results of the
impact monitoring data will therefore be compared against the results of the Baseline Environmental Monitoring Part A.
2.2
Marine Construction
Works Undertaken during Reporting Week
During the reporting period, cable repair
works were continued in Zone A and completed on 11 August 2009. Following this, the cable repair barge
“Challenger 1” demobilised on 12 August 2009. A summary of the major works undertaken
during the reporting period is shown in Table
2.1.
Table 2.1 Summary
of Marine Works Undertaken During the Reporting Week
|
Date |
Works Area |
Activity |
|
7 August 2009 |
Zone A |
Installation of split pipes and testing of water
pump burial machine. |
|
8 August 2009 |
Zone A |
Installation of split pipes. Water jetting (using silt curtain) for
re-burial of cable. |
|
10August 2009 |
Zone A |
Water jetting (using silt curtain) for re-burial of
cable. |
|
11 August 2009 |
Zone A |
Water jetting (using silt curtain) for re-burial of
final section of cable.
Completion of cable repair works. |
|
12 August 2009 |
Zone A |
Demobilisation of the cable repair barge. |
2.3
Status of
Environmental Approval Documents
A
summary of the relevant permits, licences, notifications and/or reports on
environmental protection for this Project is presented in Table 2.2.
Table 2.2 Summary
of Environmental Licensing, Notification, Permit and Reporting Status
|
Permit / Licence / Notification / Report |
Reference |
Validity Period |
Remarks |
|
Environmental Permit |
(EP-294/2007) |
Throughout the construction period |
Granted on 23 November 2008 |
|
Further Environmental Permit |
(FEP-01/294/2007) |
Throughout the construction period |
Granted on 9 July 2008 |
|
EM&A Manual |
- |
Throughout the construction period |
Approved by EPD on 12 March 2009 |
|
Baseline Water Quality Monitoring Report (Part A) |
- |
Throughout the construction period for Zones A and
E |
Approved by EPD on 1 April 2009 |
|
Baseline Water Quality Monitoring Report (Part B) |
- |
Throughout the construction period for Zones B to D |
Approved by EPD on 30 April 2009 |
|
Pre Installation Geophysical Survey Report |
- |
Throughout the construction period for the Grout
Mattress Installation |
Accepted by AFCD and EPD on 7 July 2009 |
In accordance with the EM&A Manual,
during all marine works relating to the cable, water quality sampling was undertaken
at stations situated around the cable works at
·
S1
and S2, situated at the two Seawater Intake Points in Deep Water Bay. They are within 500 m west/northwest of
the cable alignment at
·
S3, a
Sensitive Receiver used to monitor the water quality condition of the Coastal Protection Areas
at
·
B1,
an Impact Station used to monitor the effect of the construction activities on
·
R1, a
Control Station for S1, S2, S3 and B1 at
The
co-ordinates of Zone A and the above monitoring stations are listed in Table.3.1 and Table 3.2, respectively.
Table.3.1 Co-ordinates
of Starting Points and Ending Points for Zone A (HK Grid)
|
Zone |
Starting Point |
Ending Point |
||
|
Easting |
Northing |
Easting |
Northing |
|
|
A |
837029.763 |
811601.699 |
836367.572 |
810545.975 |
Table
3.2 Co-ordinates
of All Monitoring Stations in Zone A (HK Grid)
|
Station |
Nature |
Corresponding Control Station |
Easting |
Northing |
|
S1 |
Seawater
Intakes |
R1 |
836538.669 |
811528.535 |
|
S2 |
Seawater
Intakes |
R1 |
836195.047 |
810956.409 |
|
S3 |
Coastal
Protection Areas |
R1 |
836677.103 |
810666.744 |
|
B1 |
Gazetted
Beach |
R1 |
837241.114 |
811498.400 |
|
R1 |
Control Station |
- |
835951.109 |
809052.535 |
3.2
Monitoring
Parameters and Frequency
The
impact water quality monitoring was conducted in accordance with the
requirements stated in the EM&A
Manual. These are presented
below.
3.2.1
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.
3.2.2
Monitoring Frequency
Impact Monitoring at S1, S2, S3, B1 and R1 took
place while the cable repair works were undertaken within 500 m (Zone A) of
monitoring stations S1, S2, S3 and B1
Impact
monitoring was carried out during the barge operating hours, normally covering
both mid-flood and mid-ebb tidal conditions, until water quality monitoring was
not required.
In-situ
and SS data of the control and impact stations within the impact zone were collected
daily during mid-flood and mid-ebb tidal states (Table 3.3), unless the mid-ebb tide and/or the mid-flood tide were
not occurring during the monitoring period. In addition, continuous in-situ measurements were taken at the
impact monitoring stations, ie B1 & S1-3, at 30- to 60- minute intervals
(subject to the weather conditions and travelling time between stations) within
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
|
Zone |
Station Type |
Monitoring Station |
Monitoring Frequency |
Monitoring Parameter |
|
|
Mid-ebb Tide / Mid-flood Tide |
30- to 60- Minute Interval |
||||
|
A |
Control |
R1 |
Daily when cable installation works undertaken in
Zone A |
Temperature, Turbidity, Salinity, DO, SS |
- |
|
Impact |
S1, S2, S3 and B1 |
Temperature, Turbidity, Salinity, DO |
|||
3.3
Monitoring
Equipment and Methodology
3.3.1
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 an 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.
3.3.2
Monitoring Methodology
Timing & Frequency
In-situ and SS data were collected daily at both
control and impact stations in Zone A, provided that the monitoring period had
covered the mid-flood tide and/or mid-ebb tide. 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 less than 0.5 m for capturing representative tides.
Continuous In-situ
measurements were taken at 30- to 60- minute intervals (subject to the weather
conditions and travelling time between stations) for each impact station within
Zone A.
Reference was 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.
Protocols
The multi-parameter measuring instrument (YSI 6820) was checked and
calibrated by an HOKLAS accredited laboratory before use. 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 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 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 (for details refer to Annex B).
3.3.3
Action and Limit Levels
The Action and Limit levels for Zone A,
which were established based on the results of Baseline Environmental Monitoring Part 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 |
|
Dissolved Oxygen (DO) (1) |
Surface and Mid-depth (2) |
Surface and Mid-depth (2) |
|
|
5%-ile
of baseline data for surface and middle layer = 6.59 mg L-1 |
1%-ile
of baseline data for bottom layer = 6.42 mg L-1 |
|
|
|
|
|
|
Bottom |
Bottom |
|
|
5%-ile
of baseline data for bottom layers = 6.58 mg L-1 |
1%-ile of baseline for bottom layer = 6.42 mg L-1 |
|
|
|
|
|
Depth-averaged Suspended Solids (SS) (3) (4) |
95%-ile of baseline data = 7.91 mg L-1 |
99%-ile of baseline data = 8.96 mg L-1 |
|
|
or 120% of control station's SS at the same
tide of the same day |
or 130%
of control station's SS at the same tide of the same day |
|
|
|
|
|
Depth-averaged Turbidity (Tby) (3) (4) |
95%-ile of baseline data
= 5.17 NTU |
99%-ile of baseline data
= 5.72 NTU |
|
|
or 120% of control station's Tby at the same
tide of the same day |
or 130% of control station's Tby at the same
tide of the same day |
|
|
|
|
|
Notes: (1) For
DO, non-compliance of the water quality limits occurs when monitoring result
is lower than the limits. (2) The
Action and Limit Levels for DO for Surface & Middle layer were calculated
from the combined pool of baseline surface layer data and baseline middle
layer data. (3) “Depth-averaged”
is calculated by taking the arithmetic means of reading of all three depths. (4) For
turbidity and SS, non-compliance of the water quality limits occurs when
monitoring result is higher than the limits. |
||
3.3.4
Event and Action Plan
The Event and Action Plan for water
quality monitoring which was stipulated in the 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. |
For the impact monitoring, four monitoring
events were scheduled between 7 August and 11 August 2009.
Monitoring events at all designated monitoring stations were performed
on schedule, ie the four events took place on 7 August, 8 August, 10 August and
11 August.
4.1
Data Collected During Mid-Ebb and/or Mid-Flood Tidal
Conditions
Daily monitoring events were scheduled between 7 August and 11
August 2009 at
Table 4.1 Summary
of Exceedances occurring during the Reporting Week
|
|
|
Exceedance of Action and Limit Levels found at the Impact Monitoring
Stations in Zone A: |
|
|
Date |
Parameter |
Mid-Ebb Tide |
Mid-Flood Tide |
|
7
August 2009 |
DO
(Bottom) |
S1,
S2, S3, B1 |
n/a |
|
DO
(Depth-averaged) |
S1,
S2, S3, B1 |
n/a |
|
|
8
August 2009 |
DO
(Bottom) |
S1,
S2, S3, B1 |
n/a |
|
DO
(Depth-averaged) |
S1,
S2, S3, B1 |
n/a |
|
|
|
Turbidity
(Depth-averaged) |
S1* |
n/a |
|
|
SS
(Depth-averaged) |
S1 |
n/a |
|
10
August 2009 |
DO
(Bottom) |
S1,
S2, S3, B1 |
S1,
S2, S3, B1 |
|
DO
(Depth-averaged) |
S1,
S2, S3, B1 |
S1,
S3, B1 |
|
|
|
SS
(Depth-averaged) |
B1 |
S1,
S3, B1 |
|
11
August 2009 |
DO
(Bottom) |
S1,
S2, S3, B1 |
S1,
S2, S3, B1 |
|
DO
(Depth-averaged) |
S1,
S2, S3, B1 |
S3,
B1 |
|
|
|
SS
(Depth-averaged) |
B1 |
B1 |
Note:
* Action Level but not Limit Level
exceedance
n/a indicates that no sampling was taken
at that tide (due to it falling outside working hours).
4.1.1
Exceedances for Dissolved Oxygen from 7
August to 11 August 2009
Exceedances
of the Action and Limit Levels for Dissolved Oxygen (DO) were recorded daily
throughout the reporting period for bottom DO (DOB) and for depth averaged DO (Table
4.1).
It is
observed that DO trends fluctuate widely.
Similar to the results of the previous months, DOB concentrations at all
the monitoring stations appeared to be lower than the baseline data. Daily exceedances of Action and Limit
Levels set from baseline data for DOB were observed not only at the impact
monitoring stations but also at the control station, R1 and it should be noted
that the DOB levels recorded at all the impact stations were predominantly
higher than, if not comparable to the DOB measured at the control station. Similarly depth-averaged DO, although in
general lower than the baseline data, was comparable to the measurements taken
at the control station. All this
implies that the background levels of DO were also relatively low.
It
has been concluded in previous weekly reports that the recent declining trends
of dissolved oxygen and daily DO exceedances could be due to seasonal variation
such as stratification occurring during the summer. Warmer summer water temperatures speed
up the uptake of oxygen through respiration by living organisms and
decomposition of organic matter in the water column and sediments. As a result, the replenishment of dissolved
oxygen is less than the DO consumption leading to depletion in dissolved oxygen
concentrations during the summer months.
Also,
for DO, critical conditions usually occur within the bottom waters during the
summer months when the water column is stratified, with a warmer surface layer
separated from deeper water by a picnocline, or density gradient. When the density gradient within the
picnocline is high, transport of oxygen from the aerated surface waters to the
lower waters by mixing is significantly reduced. Dissolved oxygen levels could also
decrease in the bottom layer because photosynthesis and contact with the air
may be significantly reduced. This
phenomenon is supported for the reporting week by the fact that in general DOB
concentrations were lower than DO concentrations measured at the surface and
mid-depth from 7 August to 11 August 2009.
Continuous
in-situ measurements were also taken
daily at the impact monitoring stations, ie B1, S1, S2 and S3, at 30- to 60-
minute intervals. The DO levels at
the surface and middle were found to be lower in the morning but higher in the
evening (Figure 4.1). DOB levels stayed relatively similar
throughout the day (Figure 4.1). All this implies that DO concentrations
at the surface and middle depths increased throughout the day even when the
marine works took place, while DOB concentrations did not fluctuate as
much. The surface and middle depth
fluctuations can be explained by the fact that dissolved oxygen increases
during daylight hours when photosynthesis is occurring. DO is being consumed at night when
respiration continues but photosynthesis does not. The fact that DOB concentrations did not
show this clear change throughout the day re-enforces the presence of the above
mentioned picnocline in the waters of Zone A.
It is
important that although exceedances of the Action and Limit Levels for DO
occurred, no-non-compliances of the Water Quality Objectives (ie not less than
2 mg/L for 90% of samples for bottom DO and not less than 4 mg/L for 90% of
samples for depth-averaged DO) were reported.
A review of the monitoring data compared to the works
practices similarly concluded that all DO exceedances are unlikely to be caused
by the Project due to the fact that the marine works undertaken were diver hand
jetting operations inside an enclosed silt curtain and hence these construction
activities were not expected to cause decreases in the DO levels.
Figure
4.1 Continuous
Measurements of Dissolved Oxygen of Water Samples Collected at the Impact
Monitoring Stations in Zone A
|
|
In view of all of the above, the DO
exceedances were considered unlikely to be related to the Project works.
4.1.2
Exceedance for Turbidity on 8 August 2009
An exceedance of the Action Level for
Depth-averaged turbidity was recorded during the mid-ebb tide on 8 August 2009
at Station S1 (Table 4.1). Upon investigation, the exceedance was
considered unlikely to be related to the Project works for the following reasons:
·
During
the mid-ebb tide, the turbidity level measured at Station S1 was slightly
higher than the Action Level derived from the control station but it was still
below the baseline data derived Action Level.
·
At the
time of monitoring, there were no marine construction works being carried
out. The diver was out of the water
and no split-pipe installation was being carried out.
4.1.3
Exceedances for Depth-averaged Suspended
Solids on 8, 10 & 11 August 2009
An exceedance of the Action and Limit
Levels for Depth-averaged Suspended Solids (SS) was recorded on three days (8,
10 & 11 August 2009) (Table 4.1).
A review of the monitoring data and work
practices concluded that all SS exceedances, except that at B1 on 11 August
mid-flood tide, are unlikely to be caused by the Project due to the following:
·
At
the time of monitoring, no marine works were being carried out. (Stations S1 on 8 August and B1 on 10
August 2009). Any works that were
being carried out at the time of monitoring were unlikely to have caused
disturbance to the sea bed; water jetting was conducted inside a silt-curtain.
·
The
SS level did not show non-compliance during the previous and following mid-ebb
tide (Stations S1 and S3 on 10 August, mid-flood tide).
·
The
Station was upstream of the marine cable works (Station S1 on 8 August 2009, S1
& S3 on 10 August mid-ebb tide, B1 on 11 August mid-ebb tide).
·
The
exceedance was above the baseline data but well below the 120% of control
station measurement (Station B1 on 10 August, mid-ebb tide, Stations B1, S1
& S3 on 10 August mid-flood tide)
It was, therefore, considered that most of
the SS exceedances were more likely to be caused by localised factors or
temporary tidal influence rather than the Project works.
On 11 August 2009, Station B1 recorded an
SS exceedance that was above baseline and control Action and Limit levels. The station was also downstream of the
marine works and at the time of monitoring, cable re-burial was being carried
out. Therefore, the exceedance
could potentially have been caused by the Project works. Results for SS on 11 August were
received by ERM on 17 August 2009 and further investigation was not possible at
the time as the cable repair barge had already demobilised on 12 August
2009. For any future works ERM will
liaise with the contractor and ensure Project works are carried out in an
acceptable manner.
4.2
Continuous In-Situ Measurement Data
Continuous in-situ measurements were taken at the impact monitoring stations
within the required monitoring zone at 30- to 60- minute intervals (subject to
the weather conditions and travelling time between stations) and the results
and the graphical presentations were included in Annex D.
In general, the water quality in the
vicinity of the Project works was stable and acceptable throughout each
sampling day (7 August to 11 August) with the exception of some fluctuations in
depth-averaged turbidity.
5.1
Summary of
Environmental Exceedance
Some exceedances were recorded during the
monitoring period (ie 7 August to 11 August 2009) for dissolved oxygen,
turbidity and suspended solids at the monitoring stations (Table 4.1). These
exceedances were examined against the Project works and the results
incorporated into the current report (Sections 4.1.1-4.1.3). The investigations indicated that none
of the exceedances, aside from one (SS at B1 on 11 August 2009 during mid-flood
tide), were attributed to the Project construction works. The exceedance of SS at B1 on 11 August
2009 during mid-flood tide was considered potentially to be due to the Project
works but further investigation was not possible since at the time of receiving
the SS analysis results (17 August 2009) the cable repair barge had already
demobilised (on 12 August 2009).
For any future works ERM will liaise with the contractor and ensure
Project works are carried out in an acceptable manner.
5.2
Summary of
Environmental Complaint
No complaints were received during the
reporting period.
5.3
Summary of
Environmental Summons and Prosecution
No summons or prosecution on environmental
matters were received during the reporting period.
6.1
Key Issues For
The Coming Week
As there will be no cable installation
works in the following weeks, the impact monitoring will be suspended until the
resumption of the marine works.
6.2
Monitoring Schedule For The Coming Week
Since no marine works are scheduled to be
carried out in the coming week, no monitoring is scheduled to take place.
This Weekly Impact Monitoring Report
presents the EM&A work undertaken during the period from 7 August to 13
August 2009 in accordance with the EM&A Manual and the requirements under FEP-01/294/2007.
There were daily exceedances of Action and
Limit Levels for dissolved oxygen, both bottom layer (on all days) and
depth-averaged (also on all days).
There were daily exceedances of suspended solids with the exception of 7
August 2009. Such exceedances were
recorded at only one station of the four, except during the mid-flood tide on
10 August when they were recorded at three stations. Depth-averaged turbidity was compliant
with Action and Limit levels throughout the reporting period, with the
exception of one Action Level exceedance at Station S1 on 8 August. Results of detailed investigations have
indicated that with the exception of one exceedance (SS at B1 on 11 August 2009
during mid-flood tide), none of the mentioned exceedances were attributed to
the Project construction works. The
exceedance of SS at B1 on 11 August 2009 during mid-flood tide was considered
potentially to be due to the Project works but further investigation was not
possible since at the time of receiving the SS analysis results (17 August
2009) the cable repair barge had already demobilised (on 12 August 2009). For any future works ERM will liaise
with the contractor and ensure Project works are carried out in an acceptable
manner.
No complaints and
summons/prosecution were received during the reporting week.
The MT will keep track of the EM&A
programme to verify compliance of environmental requirements and the proper
implementation of all necessary mitigation measures.
