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

25^th MONTHLY PROGRESS REPORT FOR september 2014

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 September 2014, the following works were being undertaken at the CMPs:

· Capping was being undertaken at ESC CMP IVc and CMP Va;

· Disposal of contaminated mud was taking place at SB CMP 1; and

· Dredging operations were taking place at SB CMP 2.

Figure 1.1 Works Schedule for ESC CMPs and SB CMPs

1.2 Reporting Period

1.2.1 This 25^th Monthly Progress Report covers the EM&A activities for the reporting month of September 2014.

1.3 Details of Sampling and Laboratory Testing Activities

1.3.1 No monitoring activity was scheduled to be undertaken for ESC CMPs in September 2014.

1.3.2 The following monitoring activities have been undertaken for SB CMPs in September 2014:

· Impact Water Quality Monitoring during Dredging Operations was undertaken for CMP 2 three times per week on 1, 3, 5, 8, 11, 13, 15, 18, 20, 22, 24, 26 and 29 September 2014;

· Pit Specific Sediment Chemistry for CMP 1 was undertaken on 18 September 2014; and

· Water Column Profiling for CMP 1 was undertaken on 12 September 2014.

1.4 Details of Outstanding Sampling and/or Analysis

1.4.1 No outstanding sampling remained for September 2014. 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 sediment samples collected for Pit Specific Sediment Chemistry of CMP1 in September 2014.

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 25^th Monthly Progress Report:

· Impact Water Quality Monitoring during Dredging Operations of CMP 2 conducted in September 2014; and

· Water Column Profiling of CMP 1 conducted on 12 September 2014.

1.5.2 Impact Water Quality Monitoring during Dredging Operations of CMP 2 – September 2014

1.5.3 Impact Water Quality Monitoring during Dredging Operations of CMP 2 was conducted three times per week from 1 to 30 September 2014 during the reporting period. On each survey day, monitoring was conducted during both mid-ebb and mid-flood tides at two Reference (Upstream) stations and five Impact (Downstream) stations of the dredging operations at CMP 2. Monitoring was also conducted at five Sensitive Receiver Stations situated in Ma Wan, Shum Shui Kok, Tai Mo To and Tai Ho Bay. A total of twelve stations were monitored and locations of the sampling stations are shown in Figure 1.2. Monitoring at station THB2 during mid-ebb tide of 8 September 2014 and during both mid-flood 13 September 2014 were cancelled due to adverse weather condition. Sampling was only conducted at stations MW1, THB1 and WSR45C during mid-flood tide on 15 September 2014 due to adverse weather condition.

1.5.4 Monitoring results are presented in Table B1 of Annex B. Daily dredging volume in September 2014 is reported in Annex C. Levels of DO, Turbidity and SS generally complied with the Action and Limit Levels (see Table B2 of Annex B for details) set in the Baseline Monitoring Report ([7]), except for the following occasion of exceedances discussed in Table 1.1 below.

1.5.5 As presented in Table 1.1, the results indicated that the dredging operations at CMP 2 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-427/2011/A), are considered necessary for the dredging operations.

Table 1.1 Details of Exceedances Recorded at CMP 2 between 1 and 30 September 2014

Date	Tide	Parameter	Station	Type	Remarks
1 September 2014	Mid-Flood	Turbidity	DS2	Action	These exceedances were not considered as indicating any unacceptable impacts from the dredging operations to WSRs outside the works area due to the following reason: · Stations DS2, DS4, DS5, WSR45C and WSR46 are located further away from the works area of CMP 2 when compared to station DS1 at which the levels of bottom DO, surface and mid-depth DO, Turbidity and SS did not exceed the Action and Limit Levels during the same tidal period.
5 September 2014	Mid-Ebb	Surf and Mid DO	DS4	Action
5 September 2014	Mid-Ebb	Surf and Mid DO	DS5	Action
5 September 2014	Mid-Ebb	Surf and Mid DO	WSR45C	Action
5 September 2014	Mid-Flood	Bottom DO	WSR45C	Action
5 September 2014	Mid-Flood	Surf and Mid DO	WSR45C	Limit
11 September 2014	Mid-Ebb	Surf and Mid DO	DS4	Action
11 September 2014	Mid-Ebb	Surf and Mid DO	DS5	Action
11 September 2014	Mid-Ebb	Surf and Mid DO	WSR45C	Action
11 September 2014	Mid-Ebb	Turbidity	DS4	Action
11 September 2014	Mid-Ebb	Turbidity	DS5	Action
11 September 2014	Mid Flood	SS	WSR46	Action
13 September 2014	Mid-Flood	Surf and Mid DO	WSR45C	Action
13 September 2014	Mid-Flood	Surf and Mid DO	WSR46	Action
22 September 2014	Mid-Flood	SS	DS4	Action
22 September 2014	Mid-Flood	SS	WSR45C	Action
3 September 2014	Mid-Flood	Turbidity	DS1	Action	These exceedances were not considered as indicating any unacceptable impacts from the dredging operations to WSRs outside the works area due to the following reason: · Action Level Exceedance of Turbidity and SS was recorded at Station DS1 which is located at the boundary of the works area during one tidal period only, and given that the dredging rate was well within the limit as specified under the EP, it is considered that the exceedance was not indicating any unacceptable impacts from the dredging operations to the nearby WSRs.
3 September 2014	Mid-Flood	SS	DS1	Action
22 September 2014	Mid-Ebb	SS	DS1	Action
24 September 2014	Mid-Flood	SS	DS1	Action	These exceedances were not considered as indicating any unacceptable impacts from the dredging operations to WSRs outside the works area due to the following reason: · Reference station US2 has high SS level similar to the levels recorded at stations DS1 and DS3 during the same tidal period. The Action Level Exceedances of SS at stations DS1 and DS3 are considered to be isolated sporadic event which may be caused by natural background variation in water quality characteristics of the monitoring area.
24 September 2014	Mid-Flood	SS	DS3	Action

1.5.6 Water Column Profiling of CMP 1 – September 2014

1.5.7 Water Column Profiling was undertaken at a total of two sampling stations (Upstream and Downstream stations) on 12 September 2014. The water quality monitoring results have been assessed for compliance with the Water Quality Objectives (WQOs) through a review of the Environmental Protection Department (EPD) routine water quality monitoring data for the wet season period (April to October) of 2003-2012 from stations in the North Western Water Control Zone (WCZ), where CMP is located. The monitoring results were also compared with the Action and Limit Levels set in Baseline Monitoring Report (see Table B2 of Annex B for details).

In-situ Measurements

1.5.8 Analyses of results for September 2014 indicated that levels of Salinity, turbidity, DO and pH complied with the WQOs at both Downstream and Upstream stations (Table B3 of Annex B).

Laboratory Measurements for SS

1.5.9 Analyses of results for September 2014 indicated that the SS levels at Upstream station complied with the WQO. The Downstream station exceeded the WQO. SS levels at all stations complied with the Action and Limit Levels (Table B3 of Annex B).

1.5.10 Overall, the monitoring results indicated that the mud disposal operation at CMP 1 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 October 2014 for SB CMPs:

· Pit Specific Sediment Chemistry of CMP 1;

· Impact Monitoring during Dredging Operations of CMP 2;

· Routine Water Quality Monitoring of CMP 1; and

· Water Column Profiling of CMP 1.

1.6.2 No monitoring activities is scheduled to be undertaken in the next monthly period of October 2014 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.

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([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.

([7]) ERM (2012) Baseline Monitoring Report. 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 October 2012.

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