Agreement No. CE 23/2012 (EP)
Environmental Monitoring and Audit
for Contaminated Mud Pits to the South of The Brothers and at East Sha Chau (2012-2017) - Investigation

32nd MONTHLY PROGRESS REPORT FOR April 2015

1.1                                      Background

1.1.1                                Since early 1990s, contaminated sediment ([1]) arising from various construction works (e.g. dredging and reclamation projects) in Hong Kong has been disposed of at a series of seabed pits at East of Sha Chau (ESC).  In late 2008, a review indicated that the existing and planned facilities at ESC would not be able to meet the disposal demand after 2012.  In order to meet this demand, the Hong Kong Special Administrative Region Government (HKSARG) decided to implement a new contained aquatic disposal (CAD) ([2]) facility at the South of The Brothers (SB CMPs) which had been under consideration for a number of years.

1.1.2                                The environmental acceptability of the construction and operation of the Project had been confirmed by findings of the associated Environmental Impact Assessment (EIA) study completed in 2005 under Agreement No. CE 12/2002(EP) ([3]).  The Director of Environmental Protection (DEP) approved this EIA report under the Environmental Impact Assessment Ordinance (Cap. 499) (EIAO) in September 2005 (EIA Register No.: AEIAR-089/2005).

1.1.3                                In accordance with the EIA recommendation, prior to commencement of construction works for the SB CMPs, the Civil Engineering and Development Department (CEDD) undertook a detailed review and update of the EIA findings for the SB site ([4]).  Findings of the EIA review undertaken in 2009/ 2010 confirmed that the construction and operation of the SB site had been predicted to be environmentally acceptable.

 

1.1.4                                Environmental Permits (EPs) (EP-312/2008/A and EP-427/2011A) were issued by the Environmental Protection Department (EPD) to the CEDD, the Permit Holder, on 28 November 2008 for ESC CMP V and on 23 December 2011 for SB CMPs, respectively.  Under the requirements of the EPs, an Environmental Monitoring and Audit (EM&A) programme as set out in the EM&A Manuals ([5]) ([6]) is required to be implemented for the CMPs.

1.1.5                                The present EM&A programme under Agreement No. CE 23/2012 (EP) covers the dredging, disposal and capping operations of the SB CMPs as well as ESC CMPs.  Detailed works schedule for both CMPs is shown in Figure 1.1.  In April 2015, the following works were being undertaken at the CMPs:

·      Capping operations at ESC CMPs;

·      Capping operations at SB CMP 1; and

·      Disposal of contaminated mud at SB CMP 2.

Figure 1.1       Works Schedule for ESC CMPs and SB CMPs

1.2                                      Reporting Period

1.2.1                                This 32nd Monthly Progress Report covers the EM&A activities for the reporting month of April 2015.

1.3                                      Details of Sampling and Laboratory Testing Activities

1.3.1                               No monitoring activities have been undertaken for ESC CMPs in April 2015.

1.3.2                               The following monitoring activities have been undertaken for SB CMPs in April 2015:

·       Routine Water Quality Monitoring of CMP 2 was undertaken on 14 April 2015;

·       Pit Specific Sediment Chemistry of CMP 2 was undertaken on 15 April 2015; and

·       Water Column Profiling of CMP 2 was undertaken on 17 April 2015.

1.4                                      Details of Outstanding Sampling and/or Analysis

1.4.1                                No outstanding sampling remained for April 2015.  The following laboratory analyses were still in progress during the preparation of this monthly report and hence are not presented in this monthly report:

·      Laboratory analyses of Routine Water Quality Monitoring of CMP 2 in April 2015; and

·      Laboratory analyses of sediment samples collected for Pit Specific Sediment Chemistry of CMP 2 in April 2015.

1.4.2                                A summary of field activities conducted are presented in Annex A.

1.5                                      Brief Discussion of the Monitoring Results for SB CMPs

1.5.1                               Brief discussion of the monitoring results of the following activities for SB CMPs is presented in this 32nd Monthly Progress Report:

·         In-situ measurements of Routine Water Quality Monitoring of CMP 2 undertaken on 14 April 2015; and

·         Water Column Profiling of CMP 2 undertaken on 17 April 2015.

1.5.2                               Routine Water Quality Monitoring of SB CMP 2 – April 2015

1.5.3                                The monitoring results for the Routine Water Quality Monitoring conducted in April 2015 in the wet season have been assessed for compliance with the Water Quality Objectives (WQOs) set by EPD.  This consists of a review of the EPD routine water quality monitoring data for the wet season period (April to October) of 2004 - 2013 from stations in the Northwestern Water Control Zone, where the CMPs are located.  For Salinity, the averaged value obtained from the Reference stations was used for the basis as the WQO.  Levels of Dissolved Oxygen (DO) and Turbidity were also assessed for compliance with the Action and Limit Levels (see Table C1 of Annex C for details).  The monitoring results are shown in Figures 1-5 of Annex B and Table C2 of Annex C.  A total of fourteen (14) monitoring stations were sampled in April 2015 as shown in Figure 1.2. 

In-situ Measurements

1.5.4                               Analyses of results for April 2015 indicated that the levels of pH, DO and Salinity complied with the WQOs at all stations (Impact, Intermediate, Reference and Water Sensitive Receiver stations) in April 2015 (Figures 1-5 of Annex B). 

1.5.5                               The levels of DO and Turbidity complied with the Action and Limit Levels at all stations (Figures 3 and 5 of Annex B[RC1] ; Table C1 of Annex C).

1.5.6                                Overall, in-situ measurement results of the Routine Water Quality Monitoring indicated that the disposal operation at CMP 2 did not appear to cause any unacceptable impacts in water quality in April 2015. 

1.5.7                                Water Column Profiling of CMP 2 – April 2015

1.5.8                               Water Column Profiling was undertaken at a total of two sampling stations (Upstream and Downstream stations) on 17 April 2015.  The water quality monitoring results have been assessed for compliance with the WQOs as discussed in Section 1.5.3.  The monitoring results were also compared with the Action and Limit Levels set in Baseline Monitoring Report (see Table C1 of Annex C for details). 

In-situ Measurements

1.5.9                               Analyses of results for April 2015 indicated that levels of Salinity, DO and pH complied with the WQOs at both Downstream and Upstream stations (Table C3 of Annex C).  DO and Turbidity at all stations complied with the Action and Limit Levels (Table C1 and C3 of Annex C).

Laboratory Measurements for SS

1.5.10                           Analyses of results for April 2015 indicated that the Suspended Solid (SS) levels at Upstream station exceeded the WQO while Downstream station complied with the WQO.  It is considered that the exceedance of SS at Upstream station was possibly caused by natural background variation of water quality in the area.  However, both Upstream and Downstream stations complied with the Action and Limit Levels (Tables C1 and C3 of Annex C).

1.5.11                           Overall, the monitoring results indicated that the mud disposal operation at CMP 2 did not appear to cause any deterioration in water quality during this reporting period.

1.6                                     Activities Scheduled for the Next Month

1.6.1                               The following monitoring activities will be conducted in the next monthly period of May 2015 for SB CMPs:

·       Pit Specific Sediment Chemistry of CMP 2;

·       Water Column Profiling of CMP 2; and

·       Routine Water Quality Monitoring of CMP 2.

1.6.2                                No monitoring activity is scheduled to be conducted in the next monthly period of May 2015 for ESC CMPs.

1.6.3                                The sampling schedule is presented in Annex A.

1.7                                      Study Programme

1.7.1                                A summary of the Study programme is presented in Annex D.

 


([1])       According to the Management Framework of Dredged/ Excavated Sediment of ETWB TC(W) No. 34/2002, contaminated sediment in general shall mean those sediment requiring Type 2 – Confined Marine Disposal as determined according to this TC(W).

([2])        CAD options may involve use of excavated borrow pits, or may involve purpose-built excavated pits.  CAD sites are those which involve filling a seabed pit with contaminated mud and capping it with uncontaminated material such that the original seabed level is restored and the contaminated material is isolated from the surrounding marine environment.7

([3])       Detailed Site Selection Study for a Proposed Contaminated Mud Disposal Facility within the Airport East/ East of Sha Chau Area (Agreement No. CE 12/2002(EP))

([4])       Under the CEDD study Contaminated Sediment Disposal Facility to the South of The Brothers (Agreement No. FM 2/2009)

([5])          ERM (2012) Environmental Monitoring and Audit (EM&A) Manual. Final First Review.  Environmental Monitoring and Audit for Contaminated Mud Pits to the South of the Brothers and at East Sha Chau (2012-2017) – Investigation.  Agreement No. CE 23/2012(EP). Submitted to EPD in November 2012.

([6])         ERM (2010) Environmental Monitoring and Audit (EM&A) Manual. Final Second Review.  Environmental Monitoring and Audit for Contaminated Mud Pit at Sha Chau (2009-2013) – Investigation.  Agreement No. CE 4/2009(EP). Submitted to EPD in November 2010.