Agreement No. CE 4/2009 (EP)
Environmental Monitoring and Audit
for Contaminated Mud Pit at Sha Chau (2009-2013) - Investigation


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 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.

1.2                                      Reporting Period

This Monthly Progress Report covers the monitoring period of December 2010.

1.3                                      Details of Sampling and Laboratory Testing Activities

The following monitoring activities have been undertaken for CMP IV in December 2010:

·         Benthic Macro In-fauna Monitoring and Pit Specific Sediment Chemistry Monitoring were conducted on 7 December;

·         Cumulative Impact Sediment Chemistry Monitoring was conducted on 9 December;

·         Demersal Trawling was conducted on 9-10 December;

·         Sediment Toxicity Monitoring was conducted on 11 December; and

·         Water Column Profiling and Water Quality Monitoring during Capping were conducted on 16 December.

For CMP V, sampling for Impact Water Quality Monitoring during Dredging Operations was conducted 13 December.  A summary of field activities are presented in Annex A.

1.4                                      Details of Outstanding Sampling and / or Analysis

No outstanding sampling and laboratory analysis remained from December 2010. 

1.5                                      Brief Discussion of the Monitoring Results

Results of Impact Water Quality Monitoring during Dredging Operations for December 2010 are presented for CMP V.  Detailed results will be discussed in the relevant Quarterly Reports.

1.5.1                                CMP V

Impact Water Quality Monitoring during Dredging Operations of CMP V – December 2010

Impact Water Quality Monitoring during Dredging Operations of CMP V was conducted on 13 December 2010.  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) complied with the Action and Limit Levels set in the Baseline Monitoring Report ([1]).  Therefore, there appears to be no evidence of any unacceptable adverse water quality impacts arising from the dredging operations of CMP V at ESC.

1.6                                      Activities Scheduled for the Next Month

Water Column Profiling 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. 

1.7                                      Study Programme

A summary of the Study programme is presented in Annex C.


([1])        ERM (2009)  Baseline Monitoring Report.  Environmental Monitoring and Audit for Contaminated Mud Pit at Sha Chau (2009-2013) – Investigation. Agreement No. CE 4/2009(EP).  Submitted to EPD in September 2009.