Agreement No. CE 4/2009 (EP)
Environmental Monitoring and Audit
for Contaminated Mud Pit at Sha Chau (2009-2013) - Investigation
19th MONTHLY PROGRESS REPORT FOR CONTAMINATED MUD PITS AT SHA CHAU - January 2011
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 and are now taking place to construct CMP Vb. 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 Vb.
This Monthly Progress Report covers the monitoring period of January 2011.
The following monitoring activities have been undertaken for CMP IVc and CMP Vb in January 2011:
· Impact Water Quality Monitoring during Dredging Operations for CMP V was conducted on 4 January;
· Water Column Profiling for CMP IVc was conducted on 6 January; and
· Demersal Trawling for CMP IVc was conducted on 13-14 January.
A summary of field activities are presented in Annex A.
No outstanding sampling and laboratory analysis remained from January 2011.
Results of Impact Water Quality Monitoring during Dredging Operations for January 2011 are presented for CMP V. Detailed results will be discussed in the relevant Quarterly Reports.
Impact Water Quality Monitoring during Dredging Operations of CMP V was conducted on 4 January 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 V. 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 (). Levels of TSS and Turbidity exceeded the Action Level in the downstream station DS1 during the mid-ebb tide. Station DS1 is located on the edge of the works area of CMP Vb and the compliance of Action and Limit Levels at other downstream stations (ie 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 V at ESC.
Water Column Profiling, Water Quality Monitoring during Capping and Demersal Trawling will be undertaken for CMP IV while Impact Water Quality Monitoring during Dredging will be undertaken for CMP V in the next monitoring month.
The sampling schedule is presented in Annex A.
A summary of the Study programme is presented in Annex C.