Transcript Document

Earth Control Measures
at
Project Detail
Site Location
Marina Barrage
Site Location
Marina Bay Sands IR
Earth Control Measures Layout
One discharge Point
Water Treatment System
Water Storage Pond
Silt Trap
Perimeter Cut-Off Drain
with Silt Fence on both sides
Earth Control Measures Implementation
Earth Control Measures Implementation
Earth 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 Control
 much easier and more cost effective to prevent erosion
than to trap sediments
 earth work shall be sequenced and scheduled in stages
and progressively to minimize bare earth surfaces.
 All construction access and bare surfaces shall be paved
up with concrete or milled waste or other suitable
materials.
 To turf up bare surfaces immediately in an earthwork if
there is no subsequent construction activities.
 All bare slopes shall be protected with cemetitious
spray, close-turfing or erosion control blankets.
 All earth stokepiles shall be protected by canvas sheet
or erosion control blanket.
Sediment Control

To provide concrete lined cut off drains
along the perimeter of the construction
sites.

To provide sit fence properly installed and
embedded onto the ground along the
perimeter cut-off drains

Intermediate silt traps shall be installed for
every 30 metres along the perimeter lined
cut-off drain.

To provide sedimentation basins along the
perimeter cut off drains and before
discharge points into public drains.
Estimation of Surface Runoff
Estimation of Discharge Capacity
Rainfall Intensity
No of Wet days a year
Estimation of Sediment yield
Parameters adopted
Estimation of Soil Erodibility
Wheel Wash at Main entrance
Water treatment system
provided at wheel wash
Perimeter cut off drain
Concrete lining
Silt fence
Silt Traps
After exvavation, all rainwater
will be retain at basement
Concrete lining at slope
Diaphragm wall completed
Existing turfing to be retained
Main Water holding area
before treatment
Water Treatment System
Slurry discharged to slurry
collection area
Discharge of Slurry after water
treatment
Discharge of water to existing
canal after treatment
Discharge of water to existing
canal after treatment
The discharge into the storm
water drainage system shall not
contain Total Suspended Solids in
concentrations greater than 50
milligrams per litre of the discharge.
Continuous monitoring will be
implemented on site
Regular 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
site maintained regularly
Maintenance Programme
 Regular checks on the ECM that have been put in place
 The checks including the
inspection of slope, drain, erosion blanket, silt fence,
curb inlet sediment barrier, sediment tank.
Damage, choke or any problem which cause
ineffectiveness should be recorded and reported.
 The washing bays with sump pump at all
entrances/exits must be also properly maintained.
 Servicing & repair required for the ECM should be
looked into and immediate necessary repair/service or
improvement should be carried out with urgency.
Increase in composition fines
Regulation 4
TSS >50mg/l
• $1,000 and
• $2,500 in the case of a second
offence
CHECKLIST
FOR
MAINTENANCE
OF
EARTH CONTROL MEASURES
Checklist for Perimeter cut off drain
Date of inspection:
Check by:
Name of QECP
Items Description
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:
Name of ECO
Yes
No
Remarks
Checklist for silt fence
Date of inspection:
Check by:
Name of QECP
Items
1
Description
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:
Name of ECO
Yes
No
Remarks
Checklist for silt trap
Date of inspection:
Check by:
Name of QECP
Items
1
Description
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:
Name of ECO
Yes
No
Remarks
Checklist for Stabilization through laying milled waste, lean concreting, installing
erosion control blanket or vegetation
Date of inspection:
Check by:
Name of QECP
Items Description
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:
Name of ECO
Yes
No
Remarks
Checklist for Stockpile of topsoil/materials
Date of inspection:
Check by:
Name of QECP
Items
1
Description
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:
Name of ECO
Yes
No
Remarks
Checklist for Sedimentation basins
Date of inspection:
Check by:
Name of QECP
Items Description
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:
Name of ECO
Yes
No
Remarks
Checklist for wheel wash areas, entrance/ exit points
Date of inspection:
Check by:
Name of QECP
Items
1
Description
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:
Name of ECO
Yes
No
Remarks
THANK YOU . . . .