Development of the Integrated Waste Management Facilities Phase 1

The Government of Hong Kong SAR will develop the Integrated Waste Management Facilities (IWMF) Phase 1 (hereafter the Project) with incineration to achieve substantial bulk reduction of unavoidable municipal solid waste (MSW) and to recover energy from the incineration process. The IWMF will be on an artificial island to be formed by reclamation at the south-western coast of Shek Kwu Chau. Keppel Seghers Zhen Hua Joint Venture (KSZHJV) was awarded the contract under Contract No. EP/SP/66/12 Integrated Waste Management Facilities Phase 1 to construct and operate the Project.

An environmental impact assessment (EIA) study for the Project have been conducted and the EIA Report was approved under the Environmental Impact Assessment Ordinance on 17 January 2012. An Environmental Permit (EP) (EP No.: EP-429/2012) was granted to EPD on 19 January 2012 for the construction and operation of the Project. Subsequently, the EP was amended (EP No.: EP-429/2012/A) and a further EP (FEP) (EP No.: FEP-01/429/2012/A) was granted to the Keppel Seghers Zhen Hua Joint Venture (KSZHJV) on 27 December 2017.

Pursuant to Clause 2.6A of the FEP, a detailed plan on deep cement mixing for the Project shall be developed and deposited with the Director of Environmental Protection.

1.2 Purpose & Scope

The project requires the reclamation, construction of seawall and breakwater of about 12.4ha and construction of berth of about 1.9ha. Ground treatment works are required before the construction of seawall and breakwater and reclamation. Deep cement mixing will be used to reinforce the marine mud in situ.

As specified in Condition 2.6A of the FEP:

If Deep Cement Mixing (DCM) is used, at least 1 month before the commencement of DCM works of the Project, deposit 3 hard copies and 1 electronic copy of a detailed plan (the Plan) containing at least a layout arrangement and monitoring programme on DCM during the construction shall be deposited with the Director. The Plan shall provide details of mitigation measures (including sand blanket laying and silt curtain deployment) to be implemented to avoid adverse water quality impact, and the water quality monitoring programme (including monitoring locations, frequency and event / action plan) for DCM process including the sand blanket laying works.

This Detailed Plan on Deep Cement Mixing has been prepared in accordance with the FEP requirements and details the requirements. In particular, this Plan covers the following:

Ÿ Silt Curtain Arrangement for DCM works

Ÿ Water quality monitoring programme for DCM works

Ÿ Water quality monitoring locations, parameters and equipment

Ÿ Arrangements for initial intensive DCM monitoring and regular DCM monitoring

Ÿ Event and Action Plan

Ÿ Mitigation Measures to be implemented as part of the DCM process

2 OVERVIEW OF DEEP CEMENT MIXING WORKS

Prior to the DCM work, Static Loading test and DCM site trial shall be conducted first. The purpose of static loading test is to find out the data for stability checking for future detailed design and the purpose of DCM site trial is to find out the optimum mixing ratio of cement with marine sediment. Cage typed silt curtain will be deployed during laying sand blankets, laying Grade 200 or above rock and operating of deep cement mixing. According to the approved EIA report, the fine content of rock (Grade 200 or Grade 400) is negligible. A brief programme showing the tentative commencement and completion dates of the DCM works are enclosed in Appendix A.

Static Loading Test

The construction sequences for Static Loading Test are summarized as follows:

1. Laying Geotextile at seabed;

2. Laying of sand blankets with at least 2m thickness on top of geotextile, cage type silt curtain- Type 1 shall be deployed while laying sand blanket;

3. Laying Grade 200 or above rock on top of sand blanket to form a rubble mound, cage type silt curtain Type 1 shall also be deployed while laying of Grade 200 or above rock; and

4. Placing concrete blocks on top of rubble mound to form a platform to install the survey monitoring equipment.

DCM Site Trial

1. Carrying out site investigation to determine the property, grading, chemical composition of the sediment;

2. Obtaining sediment samples for laboratory investigation to produce design mix of cement slurry;

3. Placing of sand blanket, with at least 2m thickness, to cover the seabed at the area where DCM would be carried out, cage type silt curtain Type 1 shall be deployed while laying sand blanket;

4. Positioning of marine DCM barge;

5. Cage Type silt curtain Type 2 and Type 3 shall be deployed prior to commencing DCM works;

6. Inserting piling pile of mixing treatment equipment into the soft layer at the designated level;

7. Pulling up of piling pipe together with the injection of cement slurry and mixing of soft material by the agitator;

8. Monitor, control, review and adjust the cement slurry content during mixing; and

9. Repositioning of the marine DCM barge and repeat the mixing procedure until the required pattern of strengthened material is formed.

The construction sequences for DCM are similar as DCM site trials are summarized as follows:

1. Carrying out site investigation to determine the property, grading, chemical composition of the sediment;

2. Obtaining sediment samples for laboratory investigation to produce design mix of cement slurry;

3. Placing of sand blanket, with at least 2m thickness, to cover the seabed at the area where DCM would be carried out, cage type silt curtain Type 1 shall be deployed while laying sand blanket;

4. Positioning of marine DCM barge;

5. Cage Type silt curtain Type 2 and Type 3 shall be deployed prior to commencing DCM works;

6. Inserting piling pile of mixing treatment equipment into the soft layer at the designated level;

7. Pulling up of piling pipe together with the injection of cement slurry and mixing of soft material by the agitator;

8. Monitor, control, review and adjust the cement slurry content during mixing;

9. Repositioning of the marine DCM barge and repeat the mixing procedure until the required pattern of strengthened material is formed;

10. Coring of DCM samples to ensure that DCM clusters acquired sufficient strength;

11. The top level of DCM clusters shall be leveled by using grab to facilitate the installation of Caisson in later stage. Cage type silt curtain Type 1 shall be deployed while levelling the top level of DCM clusters; and

12. Lay Grade 200 or above rock on top of DCM clusters.

Laying of sand blanket and rock shall be carried out by a bottom dumping method to prevent localized overloading of the seabed and potential instability as well as minimizing loss of fines when placing the sand. The proposed method would allow sand and rock to be discharged to a point near the seabed where current dispersion would be low.

Tentative design cross section for the seawall is attached in Appendix B. Reference photographs of different types of DCM barges and DCM layout arrangement are shown in Appendix C. Prior to commencement of DCM works, various trials for equipment testing and calibration will be conducted at individual DCM barge.

2.1 Environmental Concerns related to DCM

With reference to the Supporting Document for Application for Variation of the Environmental Permit (EP-429/2012) dated September 2016, the key environmental concerns and the associated evaluation of the Key Environmental Concerns are summarized as below table.

Key Environmental Concerns	Evaluation of the Key Environmental Concern
Release of suspended solids (SS) due to DCM activities	(1) A blanket of sand would be placed on top of the sediment layer prior to DCM treatment to avoid sediment disturbance and to contain any release of cement slurry and potential suspension; and the depth of sand blanket shall be at least 2m and (2) Silt Curtains would be deployed to minimize dispersion of SS to the surrounding marine water body. (3) Provision of silt curtain in the vicinity of coral colonies.
Potential risk of contaminant release during ground treatment via DCM	(1) The potential release of sediment bound contaminants during DCM treatment would not be an issue of concern as the marine sediment at the Project site is not contaminated, which is involved only Type 1 material.
Rise in water temperature associated with the exothermic process of in-situ cement mixing	(1) Rise in water temperature is not considered to be significant as the major contact area is along the longitudinal surface of the cement-mud mixing column, thus heat dissipation would largely occur within the mud layer immediately surrounding the DCM column, which is beneath the seabed. While there would be minor heat dissipation through the upper ends of DCM columns, the heat will be absorbed by the sand blanket that will be placed on top of the seabed prior to ground improvement works. Therefore, any residual heat transfer to the water column above the sand blanket will be minimal, and potential impacts on water temperature from the DCM process would be negligible.
Disturbance to marine mammals during DCM activities (e.g. due to underwater noise)	(1) According to the results of the site trials for the Expansion of Hong Kong International Airport into a Three-Runway System, the DCM work is relatively quiet compared to other marine construction techniques, and the underwater noise generated was typically below 200Hz which is a frequency of low sensitivity of Finless Porpoises. According to Goold and Jefferson (2002)*, Finless Porpoises use narrowband and high frequency ultrasonic pulses with peak energy of 142kHz. The underwater noise generated by the DCM ground treatment is well below the acoustic range of Finless Porpoises. Therefore, no unacceptable acoustic disturbance to marine mammals from DCM works and no addition mitigation measures required.

* Goold, J. C. & Jefferson, T. A. (2002). Acoustic signals from free-ranging finless porpoises (Neophocaena phocaenoides) in the waters around Hong Kong. Raffles Bulletin of Zoology, Supplement 10: 131 139.

3 SILT CURTAIN DESIGN FOR DEEP CEMENT MIXING WORKS

3.1 Floating Type Silt Curtain

All floating silt curtains shall comprise at least the following components:

l Silt Curtain fabric

l Flotation

l Ballast chain

l Seams and Joints

l Anchors

l Warning lights / marker buoys

Silt Curtain Fabric

For silt curtains, the fabric material shall comprise a geotextile such as woven polypropylene or reinforced polyvinyl chloride (PVC) membrane. Impermeable fabrics are not recommended due to the excessive pressure that would be induced on the curtain due to tidal conditions, hence the fabric shall have a suitably low permeability that allows water to pass through under pressure, but will retain suspended solids. The fabric including seams and connecting parts shall have adequate tensile strength to withstand the pressures induced by the wind, wave and sea current conditions at the location to be deployed.

Floatation

The floatation device shall comprise flexible and buoyant units contained within a floatation sleeve or collar that is attached to the silt curtain. The buoyancy of the floatation units shall be adequate to support the full weight of the curtain including the pressure weight induced by tidal currents acting on the silt curtain surface. A freeboard of at least 10cm shall be maintained above the water surface at all times.

Ballast Chain

The ballast chain (or load lines) shall comprise a steel chain that is incorporated into the bottom hem of the silt curtain. The chain shall be sufficiently weighted to hold the curtain in a vertical position. Connecting devices from the load lines to connecting joints of the silt curtain shall be able to develop the full breaking strength of the chain.

Seams and Joints

Seams of the silt curtain fabric shall be heat sealed and shall develop the full strength of the fabric. Jointing devices such as ropes, chains and shackles shall be made of materials with adequate strength and shall not limit the full strength of the silt curtain fabric.

Anchors

Anchors shall comprise either dig type (e.g. stakes, grappling hook, plow or fluke-type) or weight type (e.g. concrete blocks) with adequate hold / weight to retain the silt curtain in the same position relative to the seabed without interfering with the action of the silt curtain. Lateral anchors (one on either side of the silt curtain) shall be attached to a floating anchor buoy via an anchor line, which connects to the top of the silt curtain. Anchor spacing should be between 15 to 30 m apart. For areas with faster current velocity, closer spacing shall be adopted as necessary to stabilize the silt curtain.

Warning Lights / Marker Buoys

To warn other marine vessels not to approach or run into the silt curtains, yellow marker buoys fitted with yellow flashing lights shall be used to indicate the position of the anchors and silt curtain system. The buoys and lights shall be located on both sides of the silt curtain at regular intervals (no more than 60m apart) along the entire length of silt curtain.

Silt Curtain Depth

The depth (vertical length from the waters surface to the bottom) of the silt curtain shall be sized to the water depth at the location of deployment. The base of the silt curtain skirt shall be anchored to within 30cm of the seabed even during high tides, hence adequate depth of silt curtain shall be allowed in the total silt curtain depth to cater for tidal changes. Given that the tidal range at the Project area can reach >2m, the base of the silt curtain may be affected by deposition of sediment during low tides. Design of the silt curtain shall take into account the potential additional drag pressure on the silt curtain due to sediment deposition at low tide.

Two layers of double floating type silt curtain shall be installed in the vicinity of coral colonies during the marine work construction period.

The typical section and layout plan of the proposed floating type silt curtain is attached in Appendix D. Specification of the proposed geotextile for the silt curtain is attached in Appendix E.

3.2 Cage Type Silt Curtain Type 1

Cage type silt curtain Type 1 shall mainly comprise the geotextile fabric with ballast chain / weight, a metal frame and associated connectors to affix the silt curtain to the frame. The frame shall be made of non-corrosive metal and properly designed to achieve structural integrity of the silt curtain.

The geotextile fabric shall be mounted and/or affixed to all four sides of the frame using seamed joints with sufficient overlap to prevent leakage of suspended solids. The silt curtain shall contain a roll up mechanism to enable the geotextile fabric to be rolled up when not in use. The design of the mechanism must enable the geotextile fabric to remain attached to the sides of the frame during roll up and roll down (i.e. prevent billowing of the fabric away from the cage frame).

Both the length of the frame and the geotextile fabric shall be measured and cut to fit the water depths at the location of deployment. The exact length shall be flexible to cater for changes in tidal level.

Cage type silt curtain Type 1 shall be used by vessels laying sand blanket and laying rock and dredging by using a closed grab method. Laying of sand blanket and Grade 200 or above rock shall be carried out by a bottom dumping method to prevent localized overloading of the seabed and potential instability as well as minimizing loss of fines when placing the sand. The proposed method would allow sand and rock to be discharged to a point near the seabed where current dispersion would be low. In addition, dredging works shall be carried out by closed grab dredger, each of grab size of not more than 2m3.

The typical section of the different cage type silt curtains are attached in Appendix F. Specification of the proposed geotextile is attached in Appendix E.

3.3 Cage Type Silt Curtain Type 2

Cage type silt curtain Type 2 shall mainly comprise the geotextile fabric with ballast chain / weight. Metal rods and associated connectors to affix the silt curtain to the electric winches installed at the boundary of DCM barge. The metal rods shall be made of non-corrosive metal and properly designed to achieve structural integrity of the silt curtain.

The geotextile fabric shall be mounted and/or affixed to all four sides of the DCM barges using seamed joints with sufficient overlap to prevent leakage of suspended solids. The silt curtain shall contain a roll up mechanism, by electric winch, to enable the geotextile fabric to be rolled up when not in use. The design of the mechanism must enable the geotextile fabric to remain attached to the sides of the DCM barge during roll up and roll down (i.e. prevent billowing of the fabric away from the DCM barge).

Cage type silt curtain Type 2 shall be used by DCM barge as a secondary layer of silt curtain while conducting DCM works.

The typical section of the different cage type silt curtains are attached in Appendix F. Specification of the proposed geotextile is attached in Appendix E.

3.4 Cage Type Silt Curtain Type 3

Cage type silt curtain Type 3 shall comprise of several layers of hollow boxes made up of metal plates. The total length of hollow box can be adjusted by using telescopic method. Electric winches shall be used to move the hollow box upward or downward so as to reach the seabed. The metal plates shall be made of non-corrosive metal and properly designed to achieve structural integrity of the silt curtain.

Cage type silt curtain Type 3 shall be used by DCM barge in the vicinity of drilling rod as a primary layer of silt curtain while conducting DCM works.

The typical section of the different cage type silt curtains are attached in Appendix F.

3.5 Cage Type Silt Curtain Type 4

Cage type silt curtain Type 4 shall mainly comprise the geotextile fabric with ballast chain / weight, a metal frame and associated connectors to affix the silt curtain to the frame. The frame shall be made of non-corrosive metal and properly designed to achieve structural integrity of the silt curtain.

Double layers geotextile fabric shall be mounted and/or affixed to all four sides of the frame using seamed joints with sufficient overlap to prevent leakage of suspended solids. The silt curtain shall contain a roll up mechanism to enable the geotextile fabric to be rolled up when not in use. The design of the mechanism must enable the geotextile fabric to remain attached to the sides of the frame during roll up and roll down (i.e. prevent billowing of the fabric away from the cage frame).

Cage type silt curtain Type 4 shall be used by spreader pontoon / pelican barge / sand pumping barge while conducting reclamation by using sand pumping pipe. Reclamation shall be carried out by a bottom dumping method to prevent localized overloading of the seabed and potential instability as well as minimizing loss of fines when placing the sand. The proposed method would allow sand to be discharged to a point near the seabed where current dispersion would be low.

The typical section of the different cage type silt curtains are attached in Appendix F. Specification of the proposed geotextile is attached in Appendix E.

4 SILT CURTAIN INSTALLATION

Silt curtains shall be installed completely before commencement of sand blanket laying works and Deep Cement Mixing Works. Prior to installation of silt curtains, the KSZHJV shall undertake a thorough check for defects and / or damages particularly in the silt curtain fabric, at the seams, and at the jointing / connector locations. Any defects and / or damages shall be rectified before commencing installation.

Floating Type Silt Curtain

The furled floating silt curtains shall be launched into the sea by derrick / crane boats / seawalls and floated into position. Anchors shall be carefully lowered to the seabed at the specified intervals. Care shall be taken to ensure that lateral anchor points are in the correct positions prior to attaching the anchor lines / anchor buoy to the silt curtain. After attaching the silt curtain to the anchors and before unfurling the silt curtains, a check shall be conducted on the lay of the curtain to confirm the positioning and slack allowances are correct. Where necessary, final adjustments should be made to the anchors, before the furling lines are released to allow the silt curtain skirt to drop. Where base anchors are also required, connection of the anchor lines to the silt curtain shall be done by divers after unfurling the silt curtain.

Cage Type Silt Curtains

The assembled cage frame shall be securely attached to the section of the construction vessel involved in the marine works (e.g. around the grab of the grab dredger). The rolled up silt curtains attached to the cage frame should be lowered to seabed level after the frame position has been fixed and the vessel is in the correct location for the marine works.

5 SILT CURTAIN MAINTENANCE

On board supervisors will be assigned to check the condition of the silt curtain before commencement of works every day. An inspection checklist will be prepared and filled in by the site supervisors. All checklists will be kept on site for record purpose. The sample of Silt Curtain Inspection Checklist is attached in Appendix G.

For the tentative arrangement of silt curtain under adverse weather, the silt curtain will not be temporary removed. However, related works will be suspended immediately if silt curtain is found any damage. The damaged silt curtain shall be lifted up from water by grab dredger / derrick barge. Double line sew a new piece of geotextile to the existing geotextile to cover the damaged area. The overlapping length shall be at least 300mm. The marine works involving the requirement for using of silt curtain shall only be commenced after the damaged silt curtain is repaired.

Refuse around the silt curtains will be collected at regular intervals on a daily basis so that water behind the silt curtains will be kept free from floating debris.

Sufficient spare geotextiles will be kept on site for replacing of damaged silt curtains. The spare geotextiles shall be covered with tarpaulin sheets to avoid direct contact with water and sunlight.

6 SILT CURTAIN REMOVAL / REPOSITIONING

Prior to removal of silt curtains, all marine works for which the silt curtains are deployed shall be stopped and visual inspection of the water quality within the area protected by silt curtains shall be conducted to confirm no sediment plume remaining within the works area before commencing silt curtain removal.

Floating Type Silt Curtain

Floating silt curtains shall be removed by detaching the chain connecting the silt curtain to the anchors, before rolling up and lifting the silt curtains and marker buoys / lights onto derrick / crane boats. Care should be taken to protect the silt curtain skirt from damage as it is dragged from the water. The remaining anchors shall be individually connected to the crane by divers and carefully lifted off the seabed for recovery onto the boats to minimize disturbance to the seabed.

Cage Type Silt Curtains

For cage type silt curtains, the silt curtains shall be rolled up and either securely wrapped to the top of the frame or detached from the frame completely before the cage frame is lifted and removed or re-positioned as required. Re-installation where required, shall follow the procedures specified in Section 4.

7 WATER QUALITY MONITORING REQUIREMENTS

7.1 Scope of Water Quality Monitoring for DCM Works

Type of DCM Monitoring

The monitoring requirements for DCM activities are divided into the following three types:

l Baseline Monitoring to obtain baseline water quality prior to the commencement of DCM works of the projects

l Initial Intensive DCM Monitoring to undertake in-depth monitoring of a specific group of DCM rigs for a minimum duration to ascertain the environmental acceptability of the DCM works

l Regular DCM Monitoring to maintain regular monitoring on DCM activities for the duration of DCM works and provide a mechanism for re-initiation of intensive DCM monitoring when necessary

Water Quality Parameters to be Monitored

For each type of monitoring related to DCM works, the water quality parameters to be monitored are summarized in Table 1.

Table 1 Water Quality Parameters

Water Quality Parameters	Baseline Monitoring	Initial Intensive DCM Monitoring	Regular DCM Monitoring
Dissolved Oxygen (DO)	x	x	x
pH	x	x	x
Temperature	x	x	x
Turbidity	x	x	x
Suspended Solids (SS)	x	x	x
Total Alkalinity	x	x	x
Water depth	x	x	x
Current Velocity and direction	x	x	x

x Parameters to be tested

7.2 Monitoring Equipment and Procedures

Monitoring of DO, pH, temperature, turbidity as well as water depth, current velocity and direction should be measured in-situ whereas SS and Total Alkalinity should be sampled and then determined by laboratory. The equipment required for each type of monitoring are specified below.

Data record sheets shall be completed for each monitoring location. Sample data record sheets based on the one presented in the EM&A Guideline for Development Projects in Hong Kong are shown in Appendix H.

In-situ Monitoring

l Dissolved Oxygen Measuring Equipment the instrument should be portable and weatherproof using a DC power source. It should be capable of measuring a dissolved oxygen level in the range of 0-20mg/L and 0-200% saturation.

l pH Measuring Equipment a portable pH meter capable of measuring a range between 0.0 and 14.0 should be provided to measure pH under the specified conditions according to the Standard Methods, APHA.

l Temperature Measuring Equipment the instrument should be portable and weatherproof using a DC power source. It should be capable of measuring a temperature of 0-45 degree Celsius with a capability of measuring to ±0.1 degree Celsius.

l Turbidity Measuring Equipment the instrument should be portable and weatherproof using a DC power source. It should have a photoelectric sensor capable of measuring turbidity between 0-1000NTU.

l Total Alkalinity a digital titrator should be provided to measure the amount of sulphuric acid used in determination of total alkalinity

l Positioning Device a hand held or boat fixed type differential Global Positioning System (dGPS) with way point bearing indication or other equivalent instrument of similar accuracy should be provided and used during monitoring to ensure the monitoring vessel is at the correct location before taking measurements

l Water Depth Detector a portable, battery-operated echo sounder should be used for the determination of water depth at each designated monitoring station. The unit would either be handheld or affixed to the bottom of the work boat, if the same vessel is to be used throughout the monitoring programme.

l Current Meter a portable, electronic current meter usch as Valeport 108 MKIII current meter or product having equivalent functions and / or performance should be used for measuring current velocity and direction.

Calibration of In-situ Instruments

All in-situ monitoring instrument should be checked, calibrated and certified by a laboratory accredited under the Hong Kong Laboratory Accreditation Scheme (HOKLAS) or other international accreditation scheme that is HOKLAS-equivalent before use, and subsequently re-calibrated at three monthly intervals throughout all stages of the water quality monitoring. Responses of sensors and electrodes should be checked with certified standard solutions before each use.

For the on-site calibration of field equipment, the BS 1427:2009, Guide to on-site test methods for the analysis of waters should be observed.

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.

Water Samples for Laboratory Testing

Collection of Water Samples

Water samples for all monitoring parameters should be collected, stored, preserved and analysis according to the Standard Methods, APHA 22nd ed. and/or other methods as agreed by the EPD.

A water sampler comprises a transparent PVC cylinder, with a capacity of not less than two litres, and could be effectively sealed with latex cups at both ends should be used. 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. Kahlsico Water Sampler or a similar instrument approved by the ET and SO should be used.

Water samples should be stored in high density polythene bottles with no preservative added, packed in ice (cooled to 4 ºC without being frozen), delivered to the laboratory within 24 hours of collection.

Laboratory Measurement / Analysis

Analysis of Total Alkalinity and SS should be carried out in a HOKLAS accredited laboratory (or other international accredited laboratory that is HOKLAS-equivalent). Sufficient water samples should be collected at the monitoring stations for carrying out the laboratory determination. The laboratory determination work should start within 24 hours after receipt of the water samples. The analysis should follow the standard methods summarised in Table 2.

Table 2: Laboratory analysis for SS, nutrient and heavy metals

Parameters	Instrumentation	Analytical Method	Reporting Limit
Suspended Solids (SS)	Analytical Balance	APHA 2540D	1 mg/L
Total Alkalinity	Titration	APHA 2320	0.01 mg/L

Additional duplicate samples may be required by EPD for inter laboratory calibration. Remaining samples after analysis should be kept by the laboratory for three months in case repeat analysis is required.

8 BASELINE MONITORING

8.1 Purpose

The purpose of the baseline monitoring is to establish ambient conditions prior to the commencement of the DCM works of the project. These baseline conditions shall be established by measuring DO, pH, temperature, turbidity, SS, total alkalinity, current velocity and direction at designated monitoring stations. Current velocity, direction and total alkalinity are required to be measured specific for DCM works, while other parameters are same as the ones required by baseline marine water quality monitoring for both dry season (monitored between 26 February 2018 and 26 March 2018) and wet season (monitored between 13 August 2018 and 7 September 2018). Baseline monitoring of current velocity, direction and total alkalinity for DCM works will be conducted before the commencement of DCM works.

8.2 Timing

Baseline Water Quality Monitoring for DCM works shall be conducted prior to the commencement of the DCM works of the project.

8.3 Monitoring Locations

Baseline water quality for the DCM works will be measured at the monitoring stations as listed in Table 3 and illustrated in Figure 1. The locations of these DCM monitoring stations will be the same as those for the IWMFs marine water quality monitoring stations during construction stage. DO, pH, temperature, turbidity, SS, total alkalinity, current velocity and direction are measured at all the DCM monitoring stations.

Table 3 Proposed Monitoring Stations for DCM Works (for Baseline Monitoring and Regular DCM Monitoring)

Station	Description	Easting	Northing	DCM Parameters	Other Parameters
B1	Beach Cheung Sha Lower	813342	810316	Total Alkalinity, Current Velocity and direction	DO, pH, Temperature, Turbidity, SS
B2	Beach Pui O	815340	811025
B3	Beach Yi Long Wan	817210	808395
B4	Beach Tai Long Wan	817784	808682
H1	Horseshoe Crab Shek Kwu Chau	816477	806953
C1	Control Station	810850	806288
C1A	Control Station (latest)	812823	806300
C2	Control Station	819421	808053
C2A	Control Station (latest)	818869	806808
F1	Cheung Sha Wan Fish Culture Zone	818631	810966
F1A	Cheung Sha Wan Fish Culture Zone (latest)	819109	810924
S1	Submarine Cable Landing Site	814245	810335
S2	Submarine Cable	815076	807747
S2A	Submarine Cable (latest)	814808	808515
S3	Submarine Cable Landing Site	816420	805621
CR1	Coral	817144	805597
CR2	Coral	816512	805882
M1	Tung Wan	821572	807799

Notes:

1. Baseline Monitoring of those parameters as stated in other parameters have been conducted between 26 Feb 18 to 26 Mar 18 and between 13 Aug 2018 to 7 Sept 2018 as part of the baseline marine water quality monitoring.

2. Due to fishermens requests and safety concern, there were changes of monitoring locations for C1, C2, F1 and S2. Regular monitoring shall refer to the latest coordinates of C1A, C2A, F1A and S2A.

8.4 Monitoring Procedures

The measurements will be taken three days per week, at mid-flood and mid-ebb tides, for a period of four weeks prior to the commencement of DCM works of the project. The interval between two sets of monitoring will be not less than 36 hours.

Samples will be taken at three depths (at 1m below surface, at mid-depth, and at 1m above bottom) for locations with water depth >6m. For locations with water depth between 3m and 6m, two depths (surface and bottom) were taken. Locations with water depth< 3m, only surface depth will be taken. Duplicate water samples will be taken and analysed.

There will be no DCM construction activities in the vicinity of the stations during the baseline monitoring.

8.5 Reporting

Baseline Monitoring Report for DCM works shall follow the relevant reporting requirements as specified in the EM&A Manual. The Baseline Monitoring Report for DCM works shall be certified by ET leader and verified by the IEC.

9 INITIAL INTENSIVE DCM MONITORING

9.1 Purpose

The purpose of the initial intensive DCM monitoring is to demonstrate the environmental acceptability of DCM works. The initial intensive DCM monitoring would be conducted at an early stage during DCM activities to reaffirm environmental acceptability of DCM works.

9.2 Timing

The monitoring should be conducted within 3 months of commencement of actual DCM works, during three DCM rigs operated concurrently.

The initial intensive DCM monitoring programme will be conducted for a period of at least four weeks to ensure that the criteria for various parameters are complied with. The actual duration of the initial intensive DCM monitoring may extend beyond four weeks should there be any exceedances in water quality action and limit levels.

9.3 Monitoring Locations

For initial intensive DCM monitoring, mobile impact monitoring stations shall be located within fixed distances from the DCM group works area to obtain water quality information in the immediate upstream and downstream area. The indicative location for initial intensive DCM works is shown in Appendix C.

A total of 12 nos. monitoring stations will be deployed with the following arrangement:

l Two monitoring stations upstream and at 150 m envelope of DCM group works area (Representative Control stations).

l Five monitoring stations downstream and at 150 m envelope of DCM group works area (Impact 1 stations).

l Five monitoring stations downstream and at 250 m envelope of DCM group works area (Impact 2 stations).

l Monitoring stations should be at least 50 m apart;

l Downstream monitoring stations should be perpendicular to the tidal direction.

The monitoring station arrangement is illustrated in Figure 2. DO, pH, temperature, turbidity, SS, total alkalinity, current velocity and direction should be measured at all stations.

Figure 2 - Monitoring Station Arrangement for Initial Intensive DCM Monitoring

Representative Control Station

9.4 Monitoring Frequency and Duration

Monitoring frequency and duration is linked to a feedback loop mechanism that enables re-initiation / continuation of intensive DCM monitoring should there be any exceedances in water quality action and limit levels. The feedback loop mechanism for DCM Monitoring is shown in Chart 1. The part covering intensive DCM monitoring is highlighted within the red dotted lines.

Chart 1: Flow Chart for DCM Specific Monitoring Parameters (Intensive)

Capture

*Exceedances refer to total alkalinity and temperature only. These should be confirmed by ET and verified by IEC as project-related.

As illustrated in Chart 1, if no exceedance is recorded within the first two weeks, then the monitoring frequency can be reduced to every two days. If no exceedance is recorded after another two weeks, the intensive DCM monitoring will be terminated and DCM monitoring will continue as part of the regular DCM monitoring presented in Section 10.

9.5 Monitoring Procedures

Monitoring shall be conducted at mid-flood (within ± 1.75 hour of the predicted time) and mid-ebb (within ± 1.75 hour of the predicted time) tides. Samples should be taken at three depths (at 1m below surface, at mid-depth, and at 1m above bottom) for locations with water depth >6m. For locations with water depth between 3m and 6m, two depths (surface and bottom) should be taken. Locations with water depth <3m, only surface depth should be taken.

Two consecutive measurements of DO, pH, temperature (oC) turbidity (NTU), and current velocity and direction should be taken in-situ according to the stated sampling method. Water samples for SS (mg/L) and Total Alkalinity (mg/L) should be collected at the same depths. Duplicate water samples should be taken and analysed.

9.6 Action and Limit Levels

The action and limit (AL) levels for DCM-specific water quality parameters during intensive DCM monitoring are defined in Table 4.

Table 4 - Action and Limit Levels for DCM-specific Water Quality Parameters (Intensive DCM Monitoring)

Parameters	Action Level	Limit Level
Temperature in oC	1.8oC above the temperature recorded at representative control station at the same tide of the same day	2oC above the temperature recorded at representative control station at the same tide of the same day
Total Alkalinity in mg/L	95 percentile of baseline data or 120% of representative control station at the same tide of the same day, whichever is higher	99 percentile of baseline data or 130% of representative control station at the same tide of the same day, whichever is higher

Notes:

1. Non-compliance of water quality results when monitoring results is higher than the limits.

2. Depth-averaged results are used unless specified otherwise.

3. Baseline data to be adopted in the Intensive DCM monitoring are specified in the Baseline Monitoring Report for DCM works.

4. Representative control station refers to average of the two representative control stations results, unless the difference between the two representative control stations results is >25%, in which case the higher (for SS and Turbidity) and lower (for DO) of the two shall apply.

For other parameters (DO, turbidity and SS), Action and Limit levels are defined in Table 5.

Table 5 - Action and Limit Levels for Other Water Quality Parameters (Intensive DCM Monitoring)

Parameters	Action Level	Limit Level
DO in mg/L (Surface and middle)	80% of representative control station at the same tide of the same day or 4mg/L, whichever is lower.	70% of representative control station at the same tide of the same day or 4mg/L, whichever is lower
DO in mg/L (Bottom)	80% of representative control station at the same tide of the same day or 2 mg/L, whichever is lower	70% of representative control station at the same tide of the same day or 2mg/L, whichever is lower
Suspended Solids (SS) in mg/L	120% of representative control station at the same tide of the same day	130% of representative control station at the same tide of the same day
Turbidity in NTU

Notes:

1. For DO, non-compliance of water quality results when monitoring results are lower than the limits.

2. Depth-averaged results are used unless specified otherwise

3. For SS and Turbidity, non-compliance of water quality results when monitoring results are higher than the limits.

4. Baseline data to be adopted in the Intensive DCM monitoring are specified in the Baseline Monitoring Report for DCM works.

5. Representative control station refers to average of the two representative control stations results, unless the difference between the two representative control stations results is >25%, in which case the higher (for SS and Turbidity) and lower (for DO) of the two shall apply.

9.7 Event and Action Plan

The actions in accordance with the Event and Action Plan in Table 6 should be carried out if the water quality assessment criteria are exceeded at the impact monitoring stations.

Table 6 - Event and Action Plan for DCM Process during Intensive DCM Monitoring

Action

Event

Environmental Team (ET)

Independent Environmental Checker (IEC)

Supervising Officer (SO)

KSZHJV

Action level being exceeded by one sampling day

1. Repeat in-situ measurement to confirm findings;

2. Identify reasons for non-compliance and sources of impact;

3. Inform IEC and KSZHJV;

4. Check monitoring data, all plant, equipment and KSZHJVs working methods;

5. Discuss mitigation measures with IEC and KSZHJV;

6. If not already undertaking daily monitoring, increase monitoring frequency in accordance with Chart 1. (applies to DCM-specific parameters only)

1. Discuss with ET and KSZHJV on the mitigation measures;

2. Review proposals on mitigation measures submitted by KSZHJV and advise SO accordingly;

3. Assess the effectiveness of the implemented mitigation measures.

1. Discuss with IEC on the proposed mitigation measures;

2. Make agreement on the mitigation measures to be implemented;

3. Assess the effectiveness of the implemented mitigation measures.

1. Inform SO and confirm receipt of ETs notification of the non-compliance in writing;

2. Rectify unacceptable practice;

3. Check all plant and equipment;

4. Provide report of the status and condition of plant, equipment and mitigation measures to ET;

5. Consider changes of working methods;

6. Discuss with ET and IEC and propose mitigation measures.

Action Level being exceeded by more than two consecutive sampling days

1. Repeat in-situ measurement to confirm findings;

2. Identify reasons for non-compliance and sources of impact;

3. Inform IEC and KSZHJV;

4. Check monitoring data, all plant, equipment and KSZHJVs working methods;

5. Discuss mitigation measures with IEC and KSZHJV;

6. Ensure mitigation measures are implemented;

7. If not already undertaking daily monitoring, increase monitoring frequency in accordance with Chart 1. (applies to DCM- specific parameters only)

1. Discuss with ET and KSZHJV on the mitigation measures;

2. Review proposals on mitigation measures submitted by KSZHJV and advise SO accordingly;

3. Assess the effectiveness of the implemented mitigation measures.

1. Discuss with IEC on the proposed mitigation measures;

2. Make agreement on the mitigation measures to be implemented;

3. Assess the effectiveness of the implemented mitigation measures.

1. Inform SO and confirm receipt of ETs notification of the non-compliance in writing;

2. Rectify unacceptable practice;

3. Check all plant and equipment;

4. Provide report of the status and condition of plant, equipment and mitigation measures to ET;

5. Consider changes of working methods;

6. Discuss with ET and IEC and propose mitigation measures to IEC and SO within 3 working days;

7. Implement the agreed mitigation measures.

8. As directed by SO, to slow down all or part of the construction activities.

Limit Level being exceeded by one sampling day

1. Repeat in-situ measurement to confirm findings;

2. Identify reasons for non-compliance and sources of impact;

3. Inform IEC, KSZHJV and EPD;

4. Check monitoring data, all plant, equipment and KSZHJVs working methods;

5. Discuss mitigation measures with IEC, SO and KSZHJV;

6. Ensure mitigation measures are implemented;

7. If not already undertaking daily monitoring, increase monitoring frequency in accordance with Chart 1. (applies to DCM- specific parameters only)

1. Discuss with ET and KSZHJV on the mitigation measures;

2. Review proposals on mitigation measures submitted by KSZHJV and advise SO accordingly;

3. Assess the effectiveness of the implemented mitigation measures.

1. Discuss with IEC, ET and KSZHJV on the proposed mitigation measures;

2. Request KSZHJV to critically review the working methods;

3. Make agreement on the mitigation measures to be implemented;

4. Assess the effectiveness of the implemented mitigation measures.

1. Inform SO and confirm receipt of ETs notification of the non-compliance in writing;

2. Rectify unacceptable practice;

3. Check all plant and equipment;

4. Provide report of the status and condition of plant, equipment and mitigation measures to ET;

5. Consider changes of working methods;

6. Discuss with ET, IEC and SO and propose mitigation measures to IEC and SO within three working days;

7. Implement the agreed mitigation measures.

Limit Level being exceeded by more than one consecutive sampling days

1. Repeat in-situ measurement to confirm findings;

2. Identify reasons for non-compliance and sources of impact;

3. Inform IEC, KSZHJV and EPD;

4. Check monitoring data, all plant, equipment and KSZHJVs working methods;

5. Discuss mitigation measures with IEC, SO and KSZHJV;

6. Ensure mitigation measures are implemented;

7. If not already undertaking daily monitoring, increase monitoring frequency in accordance with Chart 1. (applies to DCM- specific parameters only)

1. Discuss with ET and KSZHJV on the mitigation measures;

2. Review proposals on mitigation measures submitted by KSZHJV and advise SO accordingly;

3. Assess the effectiveness of the implemented mitigation measures.

1. Discuss with IEC, ET and KSZHJV on the proposed mitigation measures;

2. Request KSZHJV to critically review the working methods;

3. Make agreement on the mitigation measures to be implemented;

4. Assess the effectiveness of the implemented mitigation measures;

5. Consider and instruct, if necessary, the KSZHJV to slow down or to stop all or part of the construction activities until no exceedance of limit level.

1. Inform SO and confirm receipt of ETs notification of the non-compliance in writing;

2. Rectify unacceptable practice;

3. Check all plant and equipment;

4. Provide report of the status and condition of plant, equipment and mitigation measures to ET;

5. Consider changes of working methods;

6. Discuss with ET, IEC and SO and propose mitigation measures to IEC and SO within three working days;

7. Implement the agreed mitigation measures;

8. As directed by SO, to stop all or part of the construction activities.

Notes:

DCM- specific parameters refers to Total Alkalinity, temperature only

9.8 Reporting

Findings from the initial intensive DCM monitoring will be used to review the monitoring requirements for all parameters for regular DCM monitoring. For any re-initiated intensive DCM monitoring, these shall be reported as part of the relevant Monthly EM&A Report and the subsequent Quarterly EM&A Report. The reporting requirements shall follow the relevant requirements specified in the EM&A Manual.

10 REGULAR DCM MONITORING

10.1 Purpose

The purpose of the regular DCM monitoring is to maintain a check on the environmental acceptability of DCM works throughout the duration of DCM works, and to provide a mechanism for re-initiation of intensive DCM monitoring in the event of exceedances in water quality limits arising from the DCM activities.

10.2 Timing

During and after the DCM field trial, early regular DCM monitoring will be conducted to maintain a check on the early DCM works until initial intensive DCM monitoring commences. After completion of the initial intensive DCM monitoring, the regular DCM monitoring will continue for the remaining duration of the DCM works. Exact timing of commencement of the regular DCM monitoring programme is subject to the date of commencement of DCM works, and the date of completion of initial intensive DCM monitoring.

Regular DCM monitoring would be temporarily halted whenever intensive DCM monitoring is re-initiated, and would re-commence once the intensive DCM monitoring process has been completed with no further exceedances detected.

Regular DCM monitoring shall continue for another 4 week period after the completion of DCM works in order to confirm there are no impacts on water aspect at nearby water sensitive receivers.

10.3 Parameters for Regular DCM Monitoring

During regular DCM monitoring, DO, pH, temperature, turbidity, SS, total alkalinity and current velocity and direction will be monitored.

10.4 Monitoring Locations

Due to fishermens request and safety concern, there were changes of monitoring locations for C1, C2. F1 and S2. Regular DCM Monitoring for water quality for the DCM works was measured at the latest coordinates of monitoring stations as listed in Table 3 and illustrated in Figure 1. The locations of these DCM monitoring stations are the same as those for the IWMFs marine water quality monitoring stations during construction stage. DO, pH, temperature, turbidity, SS, total alkalinity, current velocity and direction are measured at all the DCM monitoring stations.

10.5 Monitoring Frequency and Duration

Monitoring frequency and duration is linked to a feedback loop mechanism that enables the regular DCM monitoring to be changed to intensive DCM monitoring should there be any exceedances in water quality limit levels for the DCM-specific parameters. The feedback loop mechanism for DCM Monitoring is shown in Chart 2.

Chart 2 - Flow Chart for DCM Specific Monitoring Parameters (Regular DCM Monitoring)

Capture2

*Exceedances refer to total alkalinity and temperature only. These should be confirmed by ET and verified by IEC as project-related.

As illustrated in Chart 2, regular DCM monitoring of three times per week will continue for the duration of DCM works unless there is any exceedance of the limit levels for total alkalinity for two consecutive sampling days and such exceedance is confirmed by the ET (with verification by the IEC) to be a result of the DCM works. If such instances arise, intensive DCM monitoring will be re-initiated as shown in Chart 1 and will follow the procedures described in Section 9. Regular DCM monitoring will only resume once the intensive DCM monitoring process has been completed with no further exceedances detected.

Regular DCM monitoring shall continue for another 4 week period after the completion of DCM works in order to confirm there are no impacts on water aspect at nearby water sensitive receivers.

10.6 Monitoring Procedures

Two consecutive measurements of DO, pH, temperature (oC) turbidity (NTU), current velocity and direction should be taken in-situ according to the stated sampling method. Water samples for SS (mg/L) and Total Alkalinity (mg/L) measurements should be collected at the same depths. Duplicate water samples should be taken and analysed.

10.7 Action and Limit Levels

The action and limit levels for DCM-specific water quality parameters and the other water quality parameters during regular DCM water quality are tabulated in Table 7 and Table 8.

Table 7 - Action and Limit Levels for DCM-specific Water Quality Parameters (Regular DCM Monitoring)

Parameters	Action Level	Limit Level
Total Alkalinity in mg/L	95 percentile of baseline data or 120% of upstream control station at the same tide of the same day, whichever is higher	99 percentile of baseline data or 130% of upstream control station at the same tide of the same day, whichever is higher

Notes:

1. Non-compliance of water quality results when monitoring results is higher than the limits.

2. Depth-averaged are used unless specified otherwise

3. Baseline data to be adopted in the Regular DCM monitoring are specified in the Baseline Monitoring Report for DCM works.

4. With reference to Plate 5b.8 of the approved EIA report EIA-201/2011, the upstream control station shall be C2 during flood tide and C1 during ebb tide.

For other parameters (DO, turbidity and SS), Action and Limit levels are defined in Table 8.

Table 8 - Action and Limit Levels for Other Water Quality Parameters (Regular DCM Monitoring)

Parameters	Action Level	Limit Level
DO in mg/L	≦5 percentile of baseline data	≦4mg/L
Suspended Solids (SS) in mg/L	95 percentile of baseline data or 120% of upstream control station at the same tide at the same day, whichever is higher	99 percentile of baseline data or 130% of upstream control station at the same tide of the same day, whichever is higher
Turbidity in NTU	95 percentile of baseline data or 120% of upstream control station at the same tide at the same day, whichever is higher	99 percentile of baseline data or 130% of upstream control station at the same tide of the same day, whichever is higher

Notes:

1. For DO, non-compliance of water quality results when monitoring results are lower than the limits.

2. Depth-averaged results are used unless specified otherwise

3. For SS and Turbidity, non-compliance of water quality results when monitoring results are higher than the limits.

4. Baseline data to be adopted in the Regular DCM monitoring are specified in the Baseline Monitoring Report for DCM works.

5. With reference to Plate 5b.8 of the approved EIA report EIA-201/2011, the upstream control station shall be C2 during flood tide and C1 during ebb tide.

10.8 Event and Action Plan

The actions in accordance with the Event and Action Plan in Table 9 should be carried out if the water quality assessment criteria are exceeded at the impact monitoring stations.

Table 9 - Event and Action Plan for DCM Process during Regular DCM Monitoring

Action

Event

IEC

KSZHJV

Action level being exceeded by one sampling day

1. Repeat in-situ measurement to confirm findings;

2. Identify reasons for non-compliance and sources of impact;

3. Inform IEC and KSZHJV;

4. Check monitoring data, all plant, equipment and KSZHJVs working methods;

5. Discuss mitigation measures with IEC and KSZHJV;

6. If not already undertaking daily monitoring, increase monitoring frequency in accordance with Chart 1. (applies to DCM-specific parameters only)

1. Discuss with ET and KSZHJV on the mitigation measures;

2. Review proposals on mitigation measures submitted by KSZHJV and advise SO accordingly;

3. Assess the effectiveness of the implemented mitigation measures.

1. Discuss with IEC on the proposed mitigation measures;

2. Make agreement on the mitigation measures to be implemented;

3. Assess the effectiveness of the implemented mitigation measures.

1. Inform SO and confirm receipt of ETs notification of the non-compliance in writing;

2. Rectify unacceptable practice;

3. Check all plant and equipment;

4. Provide report of the status and condition of plant, equipment and mitigation measures to ET;

5. Consider changes of working methods;

6. Discuss with ET and IEC and propose mitigation measures.

Action Level being exceeded by more than two consecutive sampling days

1. Repeat in-situ measurement to confirm findings;

2. Identify reasons for non-compliance and sources of impact;

3. Inform IEC and KSZHJV;

4. Check monitoring data, all plant, equipment and KSZHJVs working methods;

5. Discuss mitigation measures with IEC and KSZHJV;

6. Ensure mitigation measures are implemented;

7. If not already undertaking daily monitoring, increase monitoring frequency in accordance with Chart 1. (applies to DCM- specific parameters only)

1. Discuss with ET and KSZHJV on the mitigation measures;

2. Review proposals on mitigation measures submitted by KSZHJV and advise SO accordingly;

3. Assess the effectiveness of the implemented mitigation measures.

1. Discuss with IEC on the proposed mitigation measures;

2. Make agreement on the mitigation measures to be implemented;

3. Assess the effectiveness of the implemented mitigation measures.

1. Inform SO and confirm receipt of ETs notification of the non-compliance in writing;

2. Rectify unacceptable practice;

3. Check all plant and equipment;

4. Provide report of the status and condition of plant, equipment and mitigation measures to ET;

5. Consider changes of working methods;

6. Discuss with ET and IEC and propose mitigation measures to IEC and SO within 3 working days;

7. Implement the agreed mitigation measures.

8. As directed by SO, to slow down all or part of the construction activities.

Limit Level being exceeded by one sampling day

1. Repeat in-situ measurement to confirm findings;

2. Identify reasons for non-compliance and sources of impact;

3. Inform IEC, Contractor and EPD;

4. Check monitoring data, all plant, equipment and KSZHJVs working methods;

5. Discuss mitigation measures with IEC, SO and KSZHJV;

6. Ensure mitigation measures are implemented;

7. If not already undertaking daily monitoring, increase monitoring frequency in accordance with Chart 1. (applies to DCM- specific parameters only)

1. Discuss with ET and KSZHJV on the mitigation measures;

2. Review proposals on mitigation measures submitted by KSZHJV and advise SO accordingly;

3. Assess the effectiveness of the implemented mitigation measures.

1. Discuss with IEC, ET and KSZHJV on the proposed mitigation measures;

2. Request KSZHJV to critically review the working methods;

3. Make agreement on the mitigation measures to be implemented;

4. Assess the effectiveness of the implemented mitigation measures.

1. Inform SO and confirm receipt of ETs notification of the non-compliance in writing;

2. Rectify unacceptable practice;

3. Check all plant and equipment;

4. Provide report of the status and condition of plant, equipment and mitigation measures to ET;

5. Consider changes of working methods;

6. Discuss with ET, IEC and SO and propose mitigation measures to IEC and SO within three working days;

7. Implement the agreed mitigation measures.

Limit Level being exceeded by more than one consecutive sampling days

1. Repeat in-situ measurement to confirm findings;

2. Identify reasons for non-compliance and sources of impact;

3. Inform IEC, KSZHJV and EPD;

4. Check monitoring data, all plant, equipment and KSZHJVs working methods;

5. Discuss mitigation measures with IEC, SO and KSZHJV;

6. Ensure mitigation measures are implemented;

7. If not already undertaking daily monitoring, increase monitoring frequency in accordance with Chart 1. (applies to DCM- specific parameters only)

1. Discuss with ET and KSZHJV on the mitigation measures;

2. Review proposals on mitigation measures submitted by KSZHJV and advise SO accordingly;

3. Assess the effectiveness of the implemented mitigation measures.

1. Discuss with IEC, ET and KSZHJV on the proposed mitigation measures;

2. Request KSZHJV to critically review the working methods;

3. Make agreement on the mitigation measures to be implemented;

4. Assess the effectiveness of the implemented mitigation measures;

5. Consider and instruct, if necessary, the KSZHJV to slow down or to stop all or part of the construction activities until no exceedance of limit level.

1. Inform SO and confirm receipt of ETs notification of the non-compliance in writing;

2. Rectify unacceptable practice;

3. Check all plant and equipment;

4. Provide report of the status and condition of plant, equipment and mitigation measures to ET;

5. Consider changes of working methods;

6. Discuss with ET, IEC and SO and propose mitigation measures to IEC and SO within three working days;

7. Implement the agreed mitigation measures;

8. As directed by SO, to stop all or part of the construction activities.

Notes:

DCM- specific parameter refers to Total Alkalinity only

10.9 Reporting

Findings from the regular DCM monitoring shall be reported as part of the Monthly and Quarterly EM&A Report. The reporting requirements shall follow the relevant requirements specified in the EM&A Manual.

11 MITIGATION MEASURES FOR DCM

11.1 General

Mitigation Measures for the IWMF Project have been specified in the approved EIA report and Supporting Document for Application for Variation of the Environmental Permit (EP-429/2012). By using DCM for ground treatment, it can construct the seawall and breakwater by using precast concrete structures. The key mitigation measures listed in this Section are thus restricted to those that are recommended for ensuring the DCM process and activities themselves do not cause adverse water quality impact and disturbance to marine mammals. The Implementation schedule for DCM works is attached in Appendix I.

11.2 Mitigation Measures for Water Aspect

Mitigation measures recommended for protecting water quality due to DCM activities include the following:

l No DCM works should be carried out within 100m to the nearest non-translocatable coral colony / colonies;

l Silt curtains should be employed to enclose the DCM field trial and any DCM work to minimize the potential impacts on water aspects; and

l A sand blanket with at least 2m thickness shall be placed on top of the marine deposit using tremie pipes / garb by using bottom dumping method prior to the DCM ground treatment to avoid sediment disturbance and minimize sediment loss.

11.3 Mitigation / Precautionary Measures for Ecology Aspect

Mitigation / precautionary measures recommended for protecting marine mammals due to DCM activities include the following:

l Implementation of marine mammal exclusion zone;

l Deployment of silt curtains is required for laying sand blanket, laying rock and during DCM works in preventing indirect ecological impacts to marine ecological resources nearby.

L	Response to EPD comment issued on 3 September 2019	16 Sept 2019
K	Response to EPD comment issued on 18 July 2019	6 August 2019
J	Section 2 and 3.2	24 Jun 2019
I	Response to EPD comment issued on 18 April 2019	30 April 2019
H	Revise Section 3.1, Appendix C2, D	20 Mar 2019
G	Response to EPDs comments dated 29 October 2018, revised Section 2, 9, 10 and 11, Appendix C, Appendix E, Appendix F & Appendix G	19 Dec 2018
F	Revised as per provision of silt curtain near coral colonies, revised the construction programme and updated the baseline water monitoring to include wet season	27 Sept 2018
E	Response to EPD comments issued on 9 July 2018	26 July 2018
D	Response to EPD comments issued on 11 June 2018	27 June 2018
C	Response to IEC comments issued on 24 Apr 2018	25 Apr 2018
B	Response to ET and IEC comments issued on 19 Apr 2018	23 Apr 2018
A	First Issue	10 Apr 2018
Rev.	Description of Modification	Date