Agreement No. CE 4/2009 (EP)
Environmental Monitoring and Audit
for Contaminated Mud Pit at Sha Chau
(2009-2013) - Investigation
30th MONTHLY PROGRESS REPORT FOR CONTAMINATED MUD PITS AT SHA
CHAU December 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. In December 2011, CMP IVc
was in operation for backfilling by contaminated mud and was anticipated to
reach its capacity in February 2012. 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. The dredging of CMPs Va and Vb
had been completed and that of CMP Vc was in
progress. 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 December 2011.
1.3
Details of Sampling and
Laboratory Testing Activities
The following monitoring
activities have been undertaken for the CMPs in
December 2011:
· Water
Quality Monitoring during Capping was
conducted for CMP IVb on 2 December;
· Benthic Recolonisation Monitoring was conducted for CMP IIId on 14 December;
· Cumulative
Impact Sediment Chemistry Monitoring and Sediment Toxicity Test were
conducted for CMP IVc on 15 December;
· Impact
Water Quality Monitoring during Dredging Operations was conducted for
CMP Vc on 22 December;
· Pit
Specific Sediment Chemistry Monitoring was conducted for CMP IVc on 16 December; and
· Water
Column Profiling was
conducted for CMP IVc on 28 December.
A summary of field activities is presented
in Annex A.
A summary of monitoring
data submitted by the Contractor for this reporting month is presented in Table 1.1.
Table 1.1 Summary
of monitoring data submitted by the Contractor for the reporting month
|
Key Task |
Monitoring Component |
Date of Results Received from the Contractor |
|
CMP V |
|
|
|
Impact
Monitoring during Dredging Operations |
Water Quality |
9 February 2012 |
|
|
|
|
1.4
Details of Outstanding
Sampling and / or Analysis
No outstanding sampling and laboratory analysis remained from December
2011.
1.5
Brief Discussion of the
Monitoring Results
1.5.1
CMP V
Impact Water Quality Monitoring during Dredging Operations
of CMP V – December 2011
Impact
Water Quality Monitoring during Dredging Operations of CMP V was conducted
on 22 December 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) complied
with the Action and Limit Levels set in the Baseline
Monitoring Report ([1]). Overall,
the results indicated that the dredging operations at CMP V did not appear to
cause any deterioration in water quality during this reporting period.
Therefore, no further
mitigation measures, except for those recommended in the Environmental Permit (EP-312/2008), are considered required for
the dredging operations of CMP V.
Overall, there is no
evidence of any unacceptable water quality impacts as a result of the dredging
operations at CMP V.
1.6
Activities Scheduled for the
Next Month
The following monitoring programmes will be conducted
in the next monthly period of January 2012:
· Water
Column Profiling for CMP IVc;
· Demersal Trawling for CMP IVc; and
· Impact
Water Quality Monitoring during Dredging Operations for CMP Vc.
The sampling schedule is presented in Annex A.
1.7
Study Programme
A summary of the Study Programme is presented in Annex C.