Agreement No. CE 4/2009 (EP)

Environmental Monitoring and Audit
for Contaminated Mud Pit at Sha Chau (2009-2013) - Investigation

 

24th MONTHLY PROGRESS REPORT FOR CONTAMINATED MUD PITS AT SHA CHAU June 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 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.

1.2                                      Reporting Period

This Monthly Progress Report covers the monitoring period of June 2011.

1.3                                      Details of Sampling and Laboratory Testing Activities

Water Column Profiling and Water Quality Monitoring during Capping Operations were conducted for CMP IV on 21 June 2011 and an additional round of Water Column Profiling was carried out on 29 June 2011 as disposal was not taking place during the previous monitoring day.  For CMP V, sampling for Impact Water Quality Monitoring during Dredging Operations was conducted on 24 June 2011.  A summary of field activities are presented in Annex A.

A summary of laboratory analysis results submitted by the Contractor in this reporting month is presented in Table 1.1. 


Table 1.1        Summary of laboratory analysis results 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

May 2011 sampling:

17 June 2011

 

 

 

1.4                                      Details of Outstanding Sampling and / or Analysis

No outstanding sampling and laboratory analysis remained from June 2011. 

1.5                                      Brief Discussion of the Monitoring Results

Results of Impact Water Quality Monitoring during Dredging Operations for June 2011 are presented for CMP V.  Detailed results will be discussed in the 8th Quarterly Report.

1.5.1                                CMP V

Impact Water Quality Monitoring during Dredging Operations of CMP V – June 2011

Impact Water Quality Monitoring during Dredging Operations of CMP V was conducted on 24 June 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) 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

The following monitoring activities will be conducted in the next monthly period of July 2011:

·           Water Column Profiling for CMP IV;

·           Demersal Trawling 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.


 



([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.