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

 

31st MONTHLY PROGRESS REPORT FOR CONTAMINATED MUD PITS AT SHA CHAU January 2012

 

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 January 2012, 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 January 2012.

1.3                                      Details of Sampling and Laboratory Testing Activities

The following monitoring activities have been undertaken for CMP IVc in January 2012:

·       Demersal Trawling was conducted on 1 and 2 January; and

·       Water Column Profiling was conducted on 16 January.

For CMP Vc, sampling for Impact Water Quality Monitoring during Dredging Operations was conducted on 12 January 2012.  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 Vc

 

 

Impact Monitoring during Dredging Operations

Water Quality

1 March 2012

 

 

 

1.4                                      Details of Outstanding Sampling and / or Analysis

No outstanding sampling and laboratory analysis remained from January 2012

1.5                                      Brief Discussion of the Monitoring Results

 

1.5.1                                CMP V

Impact Water Quality Monitoring during Dredging Operations of CMP V – January 2012

Impact Water Quality Monitoring during Dredging Operations of CMP V was conducted on 12 January 2012.  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 Vc did not appear to cause any unacceptable 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 Vc.

1.6                                      Activities Scheduled for the Next Month

The following monitoring programmes will be conducted in the next monthly period of February 2012:

CMP IV

·       Water Quality Monitoring during Capping for CMP IVc;

·       Tissue/ Whole Body Sampling for CMP IVc; and

·       Demersal Trawling for CMP IVc.

CMP V

·       Cumulative Impact Sediment Chemistry for CMP Va;

·       Sediment Toxicity Tests for CMP Va;

·       Routine Water Quality Monitoring for CMP Va;

·       Pit Specific Sediment Chemistry for CMP Va;

·       Water Column Profiling for CMP Vc; 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.


 



([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.