4.1.1 The implementation of good construction works practice as well as the mitigation measures identified in Appendix C are important to prevent pollution of marine water in the construction phase and therefore regular site audit of all the land and marine construction activities is recommended. Site audits shall include site inspections and compliance audits.
4.1.2 The water quality impact assessment conducted for this Study concluded that marine water quality impacts from the proposed Project were mainly associated with the filling activities for reclamation. Marine water quality monitoring should be carried out at selected stations before and during the proposed reclamation activities.
4.2 Piezometer Monitoring for Tunnel Construction
4.2.1 Environmental controls on groundwater during the tunneling contract would consist of 3 periods of monitoring: Baseline, Construction and Post-Construction piezometer monitoring to control the work:
Baseline
4.1.1 Baseline controls each year, or as directed by the Engineer – a full suite of hourly monitoring for a 26 hour period, wet and dry season, spring and neap tides. Concurrently, tidal reference shall also be taken hourly from the tide gauge measurement at Quarry Bay for each of the four monitoring periods. On the basis of the four sets of results the Engineer will define an acceptable baseline groundwater envelope for the tunnel section of TKO-LT Tunnel project, for the two seasons and two tides.
Construction Monitoring
4.1.2 Daily piezometer monitoring, at a time of day to be agreed with the Engineer, will be required throughout the whole period when any tunnel construction activities are carried out within +/- 50m of the piezometer gate in plan.
4.1.3 The frequency of monitoring may be increased, as directed by the Engineer, should the monitored groundwater levels step outside the defined acceptable groundwater envelope for the particular gate, season and tide.
4.1.4 Additional ad hoc piezometer monitoring may be ordered by the Engineer, if any form of recharge is required to restore the local groundwater to the acceptable envelope or that any part of the Action Plan (as defined in the EIA Table 5.18) has to be invoked as a consequence of the passage of the tunnel drive.
4.2.2 Water quality monitoring should also be conducted at the four streams within the assessment area as identified in Section 6 (locations refer to Figure 6.3, Stream 1 to 4) to prevent drying out of streams and any contamination to the groundwater due to tunnel construction. Water quality parameters including DO, pH, temperature, turbidity, SS, BOD5, TOC Total Nitrogen, Ammonia-N and Total Phosphate are recommended.
Post-Construction Monitoring
4.1.5 After completion of the tunnel construction, a 1-year post-monitoring on the groundwater levels (piezometer monitoring) above the tunnel will need to be carried out by contractor responsible for tunnel construction. The frequency of groundwater level monitoring should be proposed by the Engineer and agreed with the EPD.
4.3 Groundwater Quality Monitoring
4.3.1 The potential for impacts on groundwater within the Project area is minimal, as shown in this EIA report. However, it is proposed to carry out a baseline survey of the water quality in selected streams and monitor the water quality at these same locations during construction, to identify the presence of any impacts on water bodies in this area.
4.3.2 Water quality monitoring should be conducted at the four streams within the assessment area as identified in Section 6 of the EIA report (locations refer to Figure 6.3, Stream 1 to 4). Water quality parameters including DO, pH, temperature, turbidity, SS, BOD5, TOC Total Nitrogen, Ammonia-N and Total Phosphate are recommended. Monitoring frequencies are recommended in Table 4.1 and should be agreed with the Engineer and the EPD before conducting the monitoring.
Table 4.1 Recommended Frequencies for Monitoring Water Quality
|
Parameter |
Description |
Frequency |
|
DO, pH, Temperature, Turbidity, SS, BOD5, TOC, Total Nitrogen, Ammonia-N, Total Phosphate |
Stream 1, Stream 2, Stream 3 and Stream 4 |
Weekly/biweekly depending on works being undertaken. When the tunnel construction works are found within 50m of the location, weekly. |
4.3.3 Baseline monitoring should be conducted prior to commencement of works in accordance with the contract-specific EM&A Manual, which is prepared based on the EPD Generic Environmental Monitoring and Audit Manual. The EM&A Manual should be submitted to and approved by EPD before major works start. Action and Limit levels should be established. Where exceedances occur, action plans described in Table 4.6 should be implemented. Necessary follow up will be conducted through regular site inspection and audit.
4.4 Marine Water Quality Monitoring Schedule and Stations
4.4.1 The proposed water quality monitoring schedule should be submitted to EPD at least two weeks before the first day of the monitoring month. EPD should also be notified immediately for any changes in schedule. The monitoring stations proposed in this section are indicative subject to further review before construction phase. The status and locations of water sensitive receivers and the marine activities may change after issuing this Manual. The proposed monitoring locations should be submitted four weeks before commencement of baseline monitoring for EPD approval.
4.4.2 It is recommended to set up 6 monitoring stations at Junk Bay Coral Site – Junk Bay near Chiu Keng Wan (M1), Junk Bay Coral Site – Junk Bay (M2), Junk bay Coral Site – Junk Island (M3), Junk Bay Coral Site – Chiu Keng Wan (M4), Junk Bay Coral Site – Fat Tong Chau (M5), Tseung Kwan O Salt Water Intake (M6) and two control stations (C1 and C2). To ensure the WSRs (M1, M2, M3 and M6) which are in close vicinity to the reclamation area would not be affected by the potential water quality impact due to the filling works of the Project, four gradient stations namely G1, G2, G3 and G4 are proposed to assist in the identification of the source of impact. Monitoring stations G1, G2, G3 and G4 are located near the monitoring stations M1, M2, M3 and M6. Monitoring stations are shown in Figure 4.1 and Table 4.2. The 6 stations (M1, M2, M3, M4, M5 and M6) represent sensitive receivers, which are potentially affected by the Project during the proposed reclamation works. Stations C1 and C2 will serve as control stations. The 4 stations (G1, G2, G3 and G4) will assist in the identification of the source of impact.
Table 4.2 Proposed Marine Water Quality Stations for Baseline and Construction Phase Monitoring
|
Station |
Description |
Easting |
Northing |
|
M1 |
Junk Bay Coral Site – Junk Bay near Chiu Keng Wan |
844255 |
817565 |
|
M2 |
Junk Bay Coral Site – Junk Bay |
844076 |
817087 |
|
M3 |
Junk Bay Coral Site – Junk Island |
844491 |
817890 |
|
M4 |
Junk Bay Coral Site – Chiu Keng Wan |
843209 |
816416 |
|
M5 |
Junk Bay Coral Site – Fat Tong Chau |
845463 |
815769 |
|
M6 |
Tseung Kwan O Salt Water Intake |
845512 |
817442 |
|
C1 |
Control Station – Southeast |
844696 |
814773 |
|
C2 |
Control Station – Northwest |
842873 |
816014 |
|
G1 |
Gradient Station |
844418 |
817560 |
|
G2 |
Gradient Station |
844290 |
817384 |
|
G3 |
Gradient Station |
844488 |
817735 |
|
G4 |
Gradient Station |
844967 |
817551 |
Impact Monitoring
4.4.3 During the reclamation, monitoring should be undertaken three days per week, at mid-flood and mid-ebb tides, with sampling/measurement at the designated monitoring stations including the control stations. The interval between two sets of monitoring should not be less than 36 hours except where there are exceedances of Action and/or Limit levels, in which case the monitoring frequency will be increased. Table 4.3 shows the proposed monitoring frequency and water quality parameters.
|
Activities |
Monitoring Frequency |
Key Parameters |
|
During marine construction for TKO-LT Tunnel reclamation |
Three days per week, at mid-flood and mid-ebb tides |
Dissolved Oxygen (DO), turbidity, Suspended Solids (SS) |
Note: DO and turbidity should be measured in-situ whereas SS should be determined by laboratory.
4.4.6 If the impact monitoring data collected at the sensitive receivers (i.e. Stations M1, M2, M3, M4, M5 and M6) indicate that the Action or Limit levels as shown in Table 4.5 are exceeded, assessment should be conducted to compare the impact monitoring data with those collected at the control stations as appropriate and to identify whether the exceedance is caused by Project activities. If the data analysis results (with the aid of the monitoring data collected from gradient stations G1 to G4) indicate that the exceedance is caused by this Project, appropriate actions including lowering the working rate, or rescheduling of works should be taken and additional mitigation measures should be implemented as necessary.
Baseline Monitoring
4.4.7 Baseline conditions for marine water quality should be established and agreed with EPD prior to the commencement of works. The purpose of the baseline monitoring is to establish ambient conditions prior to the commencement of the marine construction works and to demonstrate the suitability of the proposed monitoring stations. The baseline conditions should be established by measuring DO, turbidity and SS levels at 12 selected monitoring stations as shown in Table 4.2. The baseline monitoring report should be submitted to EPD at least 4 weeks before the commencement of marine works for agreement. The baseline monitoring report should be certified by the IEC before submission to EPD.
4.4.8 The measurements should be taken at all designated monitoring stations including control stations, 3 days per week, at mid-flood and mid-ebb tides, for at least 4 weeks prior to the commencement of marine works. There should not be any marine construction activities in the vicinity of the stations during the baseline monitoring. The interval between 2 sets of monitoring should not be less than 36 hours. The sampling and measurement depths shall follow those specified for impact monitoring in Section 4.4.4 and Section 4.4.5.
Post-Construction Monitoring
4.4.9 Upon completion of all marine works, a post-project monitoring should be carried out for 4 weeks in the same manner as the impact monitoring.
Construction Site Audits
4.4.11 Site audits should include site inspections and compliance audits.
Site Inspections
4.4.12 Site inspections should be carried out by the ET and should be based on the mitigation measures for water pollution control recommended in Appendix C. In the event that the recommended mitigation measures are not fully or properly implemented, deficiency should be recorded and reported to the site management. Suitable actions are to be carried out to:
· investigate the problems and the causes;
· issue action notes to the Contractor which is responsible for the works;
· implement remedial and corrective actions immediately;
· re-inspect the site conditions upon completion of the remedial and corrective actions; and
· record the event and discuss with the Contractor for preventive actions.
Compliance Audits
4.4.13 Monitoring of the treated effluent quality from the Works Areas is required during the construction phase of the Project. The monitoring should be carried out at the pre-determined discharge point. Compliance audits are to be undertaken to ensure that a valid discharge licence has been issued by EPD prior to the discharge of effluent from the Project site. The monitoring frequency and parameters specified in the discharge licence should be fully considered during the monitoring. All monitoring requirements should be approved by EPD. The audit results reflect whether the effluent quality is in compliance with the discharge licence requirements. In case of non-compliance, suitable actions should be undertaken to:
· notify the site management for the non-compliance;
· identify the sources of pollution;
· check the implementation status of the recommended mitigation measures;
· investigate the operating conditions of the on-site treatment systems;
· implement corrective and remedial actions to improve the effluent quality;
· increase monitoring frequency until the effluent quality is in compliance with the discharge licence requirements; and
· record the non-compliance and propose preventive measures.
4.4.14 The implementation schedule for the recommended water quality mitigation measures is presented in Appendix C.
Dissolved Oxygen and Temperature Measuring Equipment
4.5.1 The instrument should be a portable and weatherproof DO measuring instrument complete with cable and sensor, and use a DC power source. The equipment should be capable of measuring:
· a DO level in the range of 0 – 20 mg/L and 0 – 200% saturation; and
· a temperature of 0 – 45 degree Celsius.
4.5.2 It should have a membrane electrode with automatic temperature compensation complete with a cable. Sufficient stocks of spare electrodes and cables should be available for replacement where necessary. (For example, YSI model 59 meter, YSI 5739 probe, YSI 5795A submersible stirrer with reel and cable or an approved similar instrument).
4.5.3 Should salinity compensation not be built-in to the DO equipment, in-situ salinity should be measured to calibrate the DO equipment prior to each DO measurement.
Turbidity Measurement Instrument
4.5.4 Turbidity should be measured in-situ by the nephelometric method. The instrument should be portable and weatherproof using a DC power source complete with cable, sensor and comprehensive operation manuals. It should have a photoelectric sensor capable of measuring turbidity between 0 - 1000 NTU (for example, Hach model 2100P or an approved similar instrument). The cable should not be less than 25m in length. The meter should be calibrated in order to establish the relationship between NTU units and the levels of suspended solids. The turbidity measurement should be carried out on split water sample collected from the same depths of suspended solids samples.
Sampler
4.5.5 A water sampler is required. It should comprise a transparent PVC cylinder, with a capacity of not less than 2 litres, which can be effectively sealed with latex cups at both ends. The sampler should have a positive latching system to keep it open and prevent premature closure until released by a messenger when the sampler is at the selected water depth (for example, Kahlsico Water Sampler or an approved similar instrument).
Water Depth Detector
4.5.6 A portable, battery-operated echo sounder should be used for the determination of water depth at each designated monitoring station. This unit can either be hand held or affixed to the bottom of the work boat, if the same vessel is to be used throughout the monitoring programme.
Salinity
4.5.7 A portable salinometer capable of measuring salinity in the range of 0 - 40 parts per thousand (ppt) should be provided for measuring salinity of the water at each monitoring location.
Sample Containers and Storage
4.5.8 Water samples for SS, UIA and E.coli determinations should be stored in suitable containers with no preservative added, packed in ice (cooled to 4℃ without being frozen) and delivered to the laboratory and analysed as soon as possible after collection. Sufficient volume of samples should be collected to achieve the detection limit.
Monitoring Position Equipment
4.5.9 A hand-held or boat-fixed type digital Differential Global Positioning System (DGPS) with way point bearing indication or other equipment instrument of similar accuracy, should be provided and used during water quality monitoring to ensure the monitoring vessel is at the correct location before taking measurements. DGPS or the equivalent instrument, calibrated at appropriate checkpoint (e.g. Quarry Bay Survey Nail at Easting 840683.49, Northing 816709.55) should be provided and used to ensure the monitoring station is at the correct position before taking measurement and water samples.
Calibration of in-situ Instruments
4.5.10 All in-situ monitoring instruments should be checked, calibrated and certified by a laboratory accredited under HOKLAS or any other international accreditation scheme before use and subsequently re-calibrated at three monthly intervals throughout all stages of the water quality monitoring programme. Responses of sensors and electrodes should be checked with certified standard solutions before each use. Wet bulb calibration for a DO meter should be carried out before measurement at each monitoring location.
4.5.11 For the on-site calibration of field equipment, the BS 127:1993, Guide to Field and On-Site Test Methods for the Analysis of Water should be observed.
4.5.12 Sufficient stocks of spare parts should be maintained for replacements when necessary. Backup monitoring equipment should also be made available so that monitoring can proceed uninterrupted even when some equipment is under maintenance, calibration, etc.
4.6.1 Other relevant data should also be recorded, including monitoring location / position, time, water depth, salinity, temperature, tidal stages, weather conditions and any special phenomena or work underway nearby.
4.6.2 A sample data record sheet is shown in Appendix B for reference.
4.7 Laboratory Measurement / Analysis
4.7.1 Analysis of SS level should be carried out in a HOKLAS or other international accredited laboratory. Sufficient water samples of not less than 2 litres should be collected at the monitoring stations for carrying out the laboratory SS determination. The suggested testing method and lowest detection limit are provided in Table 4.4.
Table 4.4 Analytical Methods to be applied to Marine Water Quality Samples
|
Determinant |
Suggested Method |
Suggested Detection Limit |
|
Suspended Solids |
APHA 2540D * |
1 mg/L |
* APHA American Public Health Association Standard Methods for the Examination of Water and Wastewater
4.7.2 Detailed testing methods, pre-treatment procedures, instrument use, Quality Assurance/Quality Control (QA/QC) details (such as blank, spike recovery, number of duplicate samples per batch, etc.), detection limits and accuracy should be submitted to EPD for approval prior to the commencement of monitoring programme. EPD may also request the laboratory to carry out analysis of known standards provided by EPD for quality assurance. The testing methods and related proposal should be checked and certified by IEC before submission to EPD for approval.
4.7.3 Additional duplicate samples may be required by EPD for inter laboratory calibration. Remaining samples after analysis should be kept by the laboratory for 3 months in case repeat analysis is required. If in-house or non-standard methods are proposed, details of the method verification may also be required to submit to EPD. In any circumstance, the sample testing should have comprehensive quality assurance and quality control programmes. The laboratory should prepare to demonstrate the programmes to EPD or his representatives when requested.
4.8.1 The water quality assessment criteria, namely Action and Limit levels are shown in Table 4.5. Should the monitoring results of the water quality parameters at any designated monitoring stations indicate that the water quality assessment criteria are exceeded, the actions in accordance with the Action Plan in Table 4.6 be carried out.
4.8.2 It is recommended that if monitoring results indicate that the reclamation activities have caused an adverse impact on water quality at the sensitive receivers, additional mitigation measures should be recommended to rectify the non-compliance or the construction programme should be carefully reviewed. If the reclamation works have caused non-compliance with WSD’s seawater quality standards at the TKO saltwater intake, WSD should be informed. The working schedule and the mitigation measures should be reviewed by the Contractor, the IEC, the ET Leader and the ER, and if necessary, works should be slowed down or suspended until such impact is reduced to an acceptable level.
4.8.3 The ET Leader should assess the effectiveness and efficiency of the proposed mitigation measures and/or remedial actions for the on-going construction activities. The performance of the water quality monitoring and audit programme should be reviewed by the ET Leader on a quarterly basis. The findings of this review should be included in the quarterly EM&A summary reports, together with any recommendations to improve the performance of the programme.
Table 4.5 Action and Limit Levels for Water Quality
|
Parameters |
Action |
Limit |
|
DO in mg L-1
|
Depth Average 5 percentile of baseline
Bottom 5 percentile of baseline data
At intake level of WSD salt water intake 5 percentile of baseline data
At Stream 1 to 4 5 percentile of baseline
|
Depth Average 4 mg L-1 or 1 percentile of baseline data
Bottom 2 mg L-1 or 1 percentile of baseline data
At intake level of WSD salt water intake 2 mg L-1 or 1 percentile of baseline data
At Stream 1 to 4 4 mg L-1 or 1 percentile of baseline
|
|
pH |
At Stream 1 to 4 6.0 - 8.9 |
At Stream 1 to 4 6.0 - 9.0
|
|
BOD5 in mg L-1
|
At Stream 1 to 4 95 percentile of baseline
|
At Stream 1 to 4 5 mg L-1 or 99 percentile of baseline
|
|
TOC in mg L-1
|
At Stream 1 to 4 95 percentile of baseline
|
At Stream 1 to 4 99 percentile of baseline
|
|
Total Nitrogen in mg L-1
|
At Stream 1 to 4 95 percentile of baseline
|
At Stream 1 to 4 99 percentile of baseline
|
|
Ammonia-N in mg L-1
|
At Stream 1 to 4 95 percentile of baseline
|
At Stream 1 to 4 99 percentile of baseline
|
|
Total Phosphate in mg L-1
|
At Stream 1 to 4 95 percentile of baseline
|
At Stream 1 to 4 99 percentile of baseline
|
|
SS in mg L-1
|
Surface 95 percentile of baseline data or 120% of upstream control station's SS at the same tide of the same day
Bottom 95 percentile of baseline data or 120% of upstream control station's SS at the same tide of the same day
At intake level of WSD salt water intake 95 percentile of baseline data
At Stream 1 to 4 95 percentile of baseline
|
Surface 99 percentile of baseline data or 130% of upstream control station's SS at the same tide of the same day
Bottom 99 percentile of baseline or 130% of upstream control station's SS at the same tide of the same day
At intake level of WSD salt water intake 10 mg L-1 or 99 percentile of baseline data
At Stream 1 to 4 25 mg L-1 or 99 percentile of baseline
|
|
Turbidity in NTU
|
Bottom 95 percentile of baseline data or 120% of upstream control station's Turbidity at the same tide of the same day
At intake level of WSD salt water intake 95 percentile of baseline data
At Stream 1 to 4 95 percentile of baseline
|
Bottom 99 percentile of baseline or 130% of upstream control station's Turbidity at the same tide of the same day
At intake level of WSD salt water intake 10 NTU or 99 percentile of baseline data
At Stream 1 to 4 99 percentile of baseline
|
Notes: 1. "depth-averaged" is calculated by taking the arithmetic means of reading of all sampling depths.
2. For DO, non-compliance of the water quality limits occurs when monitoring result is lower than the limits.
3. For turbidity and SS, non-compliance of the water quality limits occurs when monitoring result is higher than the limits.
4. All the figures given in the table are used for reference only and the EPD may amend the figures whenever it is considered as necessary.
Table 4.6 Event and Action Plan for Marine Water Quality
|
Event |
Action |
|||
|
ET |
IEC |
ER |
CONTRACTOR |
|
|
Action level being exceeded by one sampling day at water sensitive receiver(s) |
· Identify the source(s) of impact by comparing the results with those collected at the control stations as appropriate; · If exceedance is found to be caused by the reclamation activities, repeat in-situ measurement to confirm findings; · Inform IEC and contractor; · Check monitoring data, all plant, equipment and Contractor's working methods; · If exceedance occurs at WSD salt water intake, inform WSD; · Discuss mitigation measures with IEC and Contractor; · Repeat measurement on next day of exceedance. |
· Discuss with ET and Contractor on the mitigation measures; · Review proposal on mitigation measures submitted by Contractor and advise the ER accordingly; · Assess the effectiveness of the implemented mitigation measures. |
· Discuss with IEC on the proposed mitigation measures; · Make agreement on the mitigation proposal. |
· Inform the ER and confirm notification of the non-compliance in writing; · Rectify unacceptable practice; · Check all plant and equipment; · Amend working methods if appropriate; · Discuss with ET and IEC and propose mitigation measures to IEC and ER; · Implement the agree mitigation measures. |
|
Action level being exceeded by two or more consecutive sampling days at water sensitive receiver(s) |
· Identify the source(s) of impact by comparing the results with those collected at the control stations as appropriate; · If exceedance is found to be caused by the reclamation activities, repeat in-situ measurement to confirm findings; · Inform IEC and contractor; · Check monitoring data, all plant, equipment and Contractor's working methods; · Discuss mitigation measures with IEC and Contractor; · Ensure mitigation measures are implemented; · Prepare to increase the monitoring frequency to daily; · If exceedance occurs at WSD salt water intake, inform WSD; · Repeat measurement on next day of exceedance. |
· Discuss with ET and Contractor on the mitigation measures; · Review proposal on mitigation measures submitted by Contractor and advise the ER accordingly; · Assess the effectiveness of the implemented mitigation measures. |
· Discuss with IEC on the proposed mitigation measures; · Make agreement on the mitigation proposal; · Assess the effectiveness of the implemented mitigation measures. |
· Inform the Engineer and confirm notification of the non-compliance in writing; · Rectify unacceptable practice; · Check all plant and equipment and consider changes of working methods; · Discuss with ET, IEC and ER and propose mitigation measures to IEC and ER within 3 working days; · Implement the agreed mitigation measures. |
|
Limit level being exceeded by one sampling day at water sensitive receiver(s) |
· Identify the source(s) of impact by comparing the results with those collected at the control stations as appropriate; · If exceedance is found to be caused by the reclamation activities, repeat in-situ measurement to confirm findings; · Inform IEC, contractor, AFCD and EPD · Check monitoring data, all plant, equipment and Contractor's working methods; · Discuss mitigation measures with IEC, ER and Contractor; · Ensure mitigation measures are implemented; · Increase the monitoring frequency to daily until no exceedance of Limit level; · If exceedance occurs at WSD salt water intake, inform WSD. |
· Discuss with ET and Contractor on the mitigation measures; · Review proposal on mitigation measures submitted by Contractor and advise the ER accordingly; · Assess the effectiveness of the implemented mitigation measures. |
· Discuss with IEC, ET and Contractor on the proposed mitigation measures; · Request Contractor to critically review the working methods; · Make agreement on the mitigation measures to be implemented; · Assess the effectiveness of the implemented mitigation measures. |
· Inform the ER and confirm notification of the non-compliance in writing; · Rectify unacceptable practice; · Check all plant and equipment and consider changes of working methods; · Discuss with ET, IEC and ER and submit proposal of mitigation measures to IEC and ER within 3 working days of notification; · Implement the agreed mitigation measures. |
|
Limit level being exceeded by two or more consecutive sampling days at water sensitive receiver(s) |
· Identify the source(s) of impact by comparing the results with those collected at the control stations as appropriate; · If exceedance is found to be caused by the reclamation activities, repeat in-situ measurement to confirm findings; · Inform IC(E), AFCD, contractor and EPD; · Check monitoring data, all plant, equipment and Contractor's working methods; · Discuss mitigation measures with IC(E), ER and Contractor; · Ensure mitigation measures are implemented; · Increase the monitoring frequency to daily until no exceedance of Limit level for two consecutive days; · If exceedance occurs at WSD salt water intake, inform WSD. |
· Discuss with ET and Contractor on the mitigation measures; · Review proposal on mitigation measures submitted by Contractor and advise the ER accordingly; · Assess the effectiveness of the implemented mitigation measures. |
· Discuss with IC(E), ET and Contractor on the proposed mitigation measures; · Request Contractor to critically review the working methods; · Make agreement on the mitigation measures to be implemented; · Assess the effectiveness of the implemented mitigation measures; · Consider and instruct, if necessary, the Contractor to slow down or to stop all or part of the marine work until no exceedance of Limit level. |
· Inform the ER and confirm notification of the non-compliance in writing; · Rectify unacceptable practice; · Check all plant and equipment and consider changes of working methods; · Discuss with ET, IC(E) and ER and submit proposal of mitigation measures to IC(E) and ER within 3 working days of notification; · Implement the agreed mitigation measures; · As directed by the Engineer, to slow down or to stop all or part of the construction activities. |
4.9 Mitigation of Adverse Environmental Impacts
4.9.1 Mitigation measures for water quality control have been recommended in the EIA Report. The Contractor should be responsible for the design and implementation of these measures.
4.9.2 Recommended mitigation measures to minimise the adverse impacts on water quality during construction phase are detailed in section 5.8 of the EIA report. The implementation schedule for the recommended water quality mitigation measures is presented in Appendix C.