MARINA BAY SANDS IR DEVELOPEMENT

Earth Control Earth Control Measures atMeasures at

Project DetailProject Detail

Site LocationSite Location

Marina BarrageMarina Barrage

Site LocationSite Location

Marina Bay Sands IRMarina Bay Sands IR

Sheares Avenue

Sheares Avenue

Earth Control Measures LayoutEarth Control Measures LayoutWater Treatment SystemWater Treatment System

Perimeter Cut-Off Drain Perimeter Cut-Off Drain with Silt Fence on both sideswith Silt Fence on both sides

Silt TrapSilt Trap

Water Storage PondWater Storage Pond

One discharge PointOne discharge Point

Earth Control Measures ImplementationEarth Control Measures Implementation

Earth Control Measures ImplementationEarth Control Measures Implementation

Earth Control MeasuresEarth Control Measures

Earth Control measures at construction site is of greater urgency and importance now as Singapore has to harness every drop of water so that Singaporeans can enjoy clean, clear water and a healthy environment.

Erosion ControlErosion Control much easier and more cost effective to prevent erosion much easier and more cost effective to prevent erosion

than to trap sediments than to trap sediments

earth work shall be sequenced and scheduled in stages earth work shall be sequenced and scheduled in stages and progressively to minimize bare earth surfaces. and progressively to minimize bare earth surfaces.

All construction access and bare surfaces shall be All construction access and bare surfaces shall be paved up with concrete or milled waste or other paved up with concrete or milled waste or other suitable materials.suitable materials.

To turf up bare surfaces immediately in an earthwork if To turf up bare surfaces immediately in an earthwork if there is no subsequent construction activities.there is no subsequent construction activities.

All bare slopes shall be protected with cemetitious All bare slopes shall be protected with cemetitious spray, close-turfing or erosion control blankets.spray, close-turfing or erosion control blankets.

All earth stokepiles shall be protected by canvas sheet All earth stokepiles shall be protected by canvas sheet or erosion control blanket.or erosion control blanket.

Sediment ControlSediment Control To provide concrete lined cut off drains To provide concrete lined cut off drains

along the perimeter of the construction along the perimeter of the construction sites.sites.

To provide sit fence properly installed and To provide sit fence properly installed and embedded onto the ground along the embedded onto the ground along the perimeter cut-off drains perimeter cut-off drains

Intermediate silt traps shall be installed for Intermediate silt traps shall be installed for every 30 metres along the perimeter lined every 30 metres along the perimeter lined cut-off drain.  cut-off drain.  

To provide sedimentation basins along the To provide sedimentation basins along the perimeter cut off drains and before perimeter cut off drains and before discharge points into public drains. discharge points into public drains.

Estimation of Surface RunoffEstimation of Surface Runoff

Estimation of Discharge CapacityEstimation of Discharge Capacity

Rainfall IntensityRainfall Intensity

No of Wet days a yearNo of Wet days a year

Estimation of Sediment yieldEstimation of Sediment yield

Parameters adoptedParameters adopted

Estimation of Soil ErodibilityEstimation of Soil Erodibility

Wheel Wash at Main entranceWheel Wash at Main entrance

Water treatment system Water treatment system provided at wheel washprovided at wheel wash

Perimeter cut off drainPerimeter cut off drain

Concrete liningConcrete lining

Silt fenceSilt fence

Silt TrapsSilt Traps

After exvavation, all rainwater After exvavation, all rainwater will be retain at basementwill be retain at basement

Diaphragm wall completedDiaphragm wall completed

Concrete lining at slopeConcrete lining at slope

Existing turfing to be retainedExisting turfing to be retained

Main Water holding areaMain Water holding area before treatment before treatment

Water Treatment SystemWater Treatment System

Discharge of Slurry after water Discharge of Slurry after water treatmenttreatment

Slurry discharged to slurry Slurry discharged to slurry collection areacollection area

Discharge of water to existing Discharge of water to existing canal after treatmentcanal after treatment

Discharge of water to existing Discharge of water to existing canal after treatmentcanal after treatment

The discharge into the storm The discharge into the storm water drainage system shall not water drainage system shall not

contain Total Suspended Solids in contain Total Suspended Solids in concentrations greater than 50 concentrations greater than 50

milligrams per litre of the discharge.milligrams per litre of the discharge.

Continuous monitoring Continuous monitoring will bewill be implemented on siteimplemented on site

Regular MaintenanceRegular Maintenance

- cost of chemical = $0.20 to $0.60 per m3 (mixed chemical by supplier)

- assume running on full capacity for 24 hrs- for four (4) unit of ASIII-10 = $144.00 per day x 4 nos = $576.00- for two (2) unit of ASIII-40 = $288.00 per day x 2 nos = $576.00- total chemical cost per day = $1,152.00

- chemical used:- (1) Polymer = $10/kg- (2) Ferrichloride = $0.20/litre- mixing of chemical by Contractor, cost = $0.10 - $0.30 per m3- (estimated cost of chemical = HK$1,200/mth for 20/m3 18 hour)

- ASIII-10 = 20m3/hr- total capacity = 20m3 x 24hr = 480m3- chemical usage = 480m3 x $0.30/m3 = $144.00 per day- ASIII-40 = 40m3/H- total capacity = 40m3 x 24hr = 960m3- chemical usage = 960m3 x $0.30/m3 = $288.00 per day

Existing drain within construction Existing drain within construction site maintained regularlysite maintained regularly

Maintenance ProgrammeMaintenance Programme

Regular checks on the ECM that have been put in placeRegular checks on the ECM that have been put in place

The checks including the The checks including the

inspection of slope, drain, erosion blanket, silt fence, inspection of slope, drain, erosion blanket, silt fence, curb inlet sediment barrier, sediment tank. curb inlet sediment barrier, sediment tank.

Damage, choke or any problem which cause Damage, choke or any problem which cause ineffectiveness should be recorded and reported.ineffectiveness should be recorded and reported.

The washing bays with sump pump at all The washing bays with sump pump at all entrances/exits must be also properly maintained. entrances/exits must be also properly maintained.

Servicing & repair required for the ECM should be Servicing & repair required for the ECM should be looked into and immediate necessary repair/service or looked into and immediate necessary repair/service or improvement should be carried out with urgency.improvement should be carried out with urgency.

Increase in composition finesIncrease in composition fines

Regulation 4TSS >50mg/l

• $1,000 and

• $2,500 in the case of a second offence

CHECKLISTCHECKLISTFORFOR

MAINTENANCE MAINTENANCE OFOF

EARTH CONTROL MEASURESEARTH CONTROL MEASURES

Checklist for Perimeter cut off drain Date of inspection: Check by:

Name of QECP Name of ECO Items Description Yes No Remarks 1 Location according to ECM? If no, inform

contractor

2 Construction according to ECM? If no, inform contractor.

3 Any signs of damage? If yes, repair 4 Any signs of inadequate capacity

(ie flooding)? If yes, inform QECP

5 Is obstructing debris or sediment blocking drain? If yes, clear

Follow up action and date of implementation:

Checklist for silt fence Date of inspection: Check by:

Name of QECP Name of ECO Items Description Yes No Remarks 1 Installation of silt fence according to ECM? If No,

inform contractor

2 Site fence accumulated >25cm sediment? If yes, clear

3 Is the runoff water running around, above or below the fabric? If yes, fabric is choked and replacement with new fabric required.

4 Is silt fence support steady? If no, rectify 5 Is silt fence torn? If yes, replace 6 Is silt fence properly anchored?

If no, rectify.

Follow up action and date of implementation:

Checklist for silt trap Date of inspection: Check by:

Name of QECP Name of ECO Items Description Yes No Remarks 1 Installation of silt trap according to ECM? If No,

inform contractor

2 Is silt trap structure damaged? If yes, repair.

4 Is silt trap fabric torn? If yes, rectify 5 Is silt fence torn? If yes, replace 6 Is silt trap accumulated with sediment >50%

height? If yes, clear.

Follow up action and date of implementation:

Checklist for Stabilization through laying milled waste, lean concreting, installing erosion control blanket or vegetation Date of inspection: Check by:

Name of QECP Name of ECO Items Description Yes No Remarks 1 Location according to ECM? If No, inform

contractor

2 Construction according to ECM? If No, inform contractor

3 Any signs of damage for lean concrete areas? If yes, repair.

4 Any signs of damage for milled waste areas? If yes, repair.

5 Any signs of damage for erosion control mat areas? If yes, replace.

6 Any signs of damage for vegetation areas? If yes, replant or replace with suitable material.

Follow up action and date of implementation:

Checklist for Stockpile of topsoil/materials Date of inspection: Check by:

Name of QECP Name of ECO Items Description Yes No Remarks 1 Stockpile location and creation according to ECM?

If no, inform contractor

2 Properly protected against erosion? If no, refer to ECM or check with QECP.

3 Properly protected against sedimentation? If no, refer to ECM or check with QECP.

Follow up action and date of implementation:

Checklist for Sedimentation basins Date of inspection: Check by:

Name of QECP Name of ECO Items Description Yes No Remarks 1 Location and schedule according to ECM? If no,

inform contractor

2 Details of basins according to ECM?, If no, inform contractor

3 Concentration of effluent (outlet runoff) >50ppm? If yes, inform QECP

4 Sediment filled to within 30cm of water discharge level of outflow structure? If yes, remove sediment.

5 Outlet structure installed as specified in ECM? If no inform contractor.

6 Embankment (if any) protected against erosion? If no, propose measures to protect against erosion.

7 Sedimentation basin inlet chocked? If yes, clear. 8 Sedimentation basin outlet chocked? If yes, clear. 9 Sedimentation basin inlet/outlet scouring problem?

If yes, inform contractor.

Follow up action and date of implementation:

Checklist for wheel wash areas, entrance/ exit points Date of inspection: Check by:

Name of QECP Name of ECO Items Description Yes No Remarks 1 Location according to ECM? If no, inform

contractor.

2 Construction according to details? If no, inform contractor

3 Any signs of damage for concrete (or stabilized) areas? If yes, repair

4 Any signs of sediment spill from these areas into public domain? If yes, investigate.

5 Runoff from wheel wash area channel to suitable areas and properly treated?

Follow up action and date of implementation:

THANK YOU . . . .THANK YOU . . . .