Agreement No. CE 4/2009 (EP)
Environmental Monitoring and Audit
for Contaminated Mud Pit at Sha Chau
(2009-2013) - Investigation
29th MONTHLY PROGRESS REPORT FOR CONTAMINATED MUD PITS AT SHA
CHAU November 2011
1.1
Background
Since 1992, the East of Sha
Chau area has been the site of a series of dredged
contaminated mud pits (CMPs) designed to provide
confined marine disposal capacity for contaminated mud arising from the HKSAR’s dredging and reclamation projects. CMP IVc is
presently in operation for backfilling by contaminated mud and is anticipated
to reach its capacity in 2011. A series
of four newly constructed seabed pits at the East of Sha
Chau area, CMP Va-d, will
be provided for the disposal of contaminated mud after CMP IVc
is full. Dredging operations were
completed for the construction of CMP Va-b and are
now taking place to construct CMP Vc. The environmental monitoring and audit
(EM&A) programme for the CMPs at the East of Sha Chau area presently covers
disposal and capping operations at CMP IV and dredging operations at CMP Vc.
1.2
Reporting Period
This Monthly Progress Report
covers the monitoring period of November 2011.
1.3
Details of Sampling and
Laboratory Testing Activities
No field sampling was scheduled
for CMP IV in November 2011.
For CMP V, sampling for Impact Water Quality Monitoring during
Dredging Operations was conducted on
4 November 2011. A summary of field activities are presented in Annex A.
A summary of monitoring
data submitted by the Contractor in this reporting month is presented in Table 1.1.
Table 1.1 Summary
of monitoring data submitted by the Contractor during the reporting month
|
Key Task |
Monitoring Component |
Results Received from the Contractor |
|
CMP V |
|
|
|
Impact
Monitoring during Dredging Operations |
Water Quality |
October 2011 sampling: 28 November
2011 |
|
|
|
|
1.4
Details of Outstanding
Sampling and / or Analysis
No outstanding sampling and laboratory analysis remained from November
2011.
1.5
Brief Discussion of the
Monitoring Results
1.5.1
CMP V
Impact Water Quality
Monitoring during Dredging Operations of CMP V – November 2011
Impact
Water Quality Monitoring during Dredging Operations of CMP V was conducted
on 4 November 2011. On the survey day, sampling was
conducted during both mid-ebb and mid-flood tides at two Reference (Upstream)
stations upstream and five Impact (Downstream) stations downstream of the
dredging operations at CMP Vc (Figure 1.1). Monitoring was
also conducted at the Ma Wan station. At
each station, in-situ measurements of
water quality parameters as well as water samples were taken from three depths
in the water column (ie surface: 1 m below sea
surface, mid-depth and bottom: 1 m above the seabed).
Monitoring results are
presented in Table B1 of Annex B. Levels
of Dissolved Oxygen (DO), Turbidity and Total Suspended Solids (TSS) generally
complied with the Action and Limit Levels set in the Baseline Monitoring Report ([1]). Levels of
TSS and Turbidity exceeded the Action Levels in the downstream station DS1
during the mid-flood tide. Station DS1
is located on the edge of the works area of CMP Vc (Figure 1.1) and the compliance of Action
and Limit Levels at other downstream stations (i.e. DS2-4) outside the works
area would indicate that there is no evidence of any unacceptable adverse water
quality impacts arising from the dredging operations of CMP Vc
at ESC. No additional measures are thus
considered required.
1.6
Activities Scheduled for the
Next Month
The following monitoring programmes will be conducted
in the next monthly period of December 2011:
· Water
Column Profiling for CMP
IV;
· Water
Quality Monitoring during Capping for
CMP IV;
· Pit
Specific Sediment Chemistry for
CMP IV;
· Cumulative
Impact Sediment Chemistry for CMP
IV;
· Sediment
Toxicity Tests for CMP IV;
· Benthic Recolonisation Studies for CMP IV; and
· Impact
Water Quality Monitoring during Dredging Operations for CMP V.
The sampling schedule is presented in Annex A.
1.7
Study Programme
A summary of the Study Programme is presented in Annex C.