CONTENTS

Preface

o Message from SCAL o Message from PUB

1. Importance of Effective Earth Control Measure (ECM)

2. Roles of Construction Industry

3. Implementation of an Effective ECM a. Erosion Control b. Sediment Control c. Maintenance & Review

4. Submission Requirements For ECM

5. Checklist of Erosion and Sediment Control

6. Bad & Good Practices at Construction Sites

7. Legislation and Code of Practice

8. Listing of ECM Products, Services and Technology Providers

Annexes Annex 1 Roles of Construction Industry Annex 2 Sample Specifications and Itemised BQ for ECM Annex 3 Schematic Drawing for ECM at Construction Sites Annex 4 TSS Samples (50mg/l)

Preface

Message from SCAL:

The Singapore Contractors Association is pleased to collaborate with the key partners of the industry including PUB to promote good environmental practice to keep Singapore’s water catchments clean.

SCAL urges contractors to take earth control measures and prevent silty discharge from construction activities and hope that with this guidebook, contractors can help to minimize and prevent upstream pollution.

We urge all to conserve and value our scarce water resource and work together to improve the quality of water to be enjoyed by everybody.

Desmond Hill President Singapore Contractors Association Ltd

Message from PUB:

This guidebook is the result of a joint effort between the Singapore Contractors Association Ltd (SCAL) and the PUB. We are very grateful to the Association for its active participation in this publication. My sincere thanks to the President and Council Members of SCAL, and members who have contributed towards the publication of this guidebook.

We now have beautiful and clean waterways that we can be proud of. Everyone of us plays a part in keeping our waters clean. As contractors, your role is important. Through the simple and conscious act of controlling earth and silt washdowns, you can prevent your site from becoming a source of muddy waters that taint our waterways.

This guidebook is the 3 rd edition and contains an updated silt and earth control measures that construction industry has to implement at every construction site to achieve the regulated discharge standard.

We hope that you will find this guidebook useful. And together, we must do our part to ensure that our beautiful waterways and rivers remain clean and clear at all time.

With best wishes,

Tan Nguan Sen Director, Catchment & Waterways Department Public Utilities Board

1. Importance of Effective Earth Control Measures (ECM)

Singapore is well respected for our clean and green environment as well as our resourcefulness in harnessing our scarce water resources.

Over the years, we have spent much effort to clean up and beautify our rivers & waterways. This has resulted in the clean and aesthetic waterways, like Singapore River and Kallang Basin which Singaporeans enjoy today.

Singapore River

Sungei Sembawang Sungei Api Api

While our rivers and waterways are clean most of the time, we still see them turn brown during and after a rain. The silty brown water is spoiling our proud image of a green and clean Singapore.

More importantly, the silty water is hampering our effort to make every drop counts as the silt will make it more difficult and costly to treat. Over the next 1 to 3 years, more of our waterways will be dammed up to increase Singapore's robustness in water resources. By 2008, a barrage will be built across Marina Channel which will impound water from 5 major urban river catchments.

Together we can definitely do more and better to improve the quality of the storm runoffs discharging into our waterways.

What causes the river to turn brown? Silt and sediment control is a key element in our water resources management strategy. Sediments introduced into our rivers cause environmental pollution and increase flood risk… and turn our river water brown. Sediments can remain suspended for a very long time. The major source of sediments is from construction sites. Construction activities disturb existing ground cover and vegetation, and expose much bare surfaces.

(For fuller detail, please refer to ECM website: www.pub.gov.sg/ECM)

2. Roles of Construction Industry Note: The earth control measure (ECM) is meant for the control of silty discharge due to rain water. Other waste water (slurry water, bentonite etc) due to construction activities such as piling or tunneling work should be separately treated

(A) Contractor

The roles of Contractor during the whole duration of a typical project development process are summarized in the table below:

Before Commencement of

works

1. Engage QECP for detailed ECM (see schematic drawing in Annex 3)

2. Provide information on topography, soil, construction work and schedule, site facilities, etc to QECP

3. Submit ECM plan prepared and endorsed by both QECP and Contractor to PUB together with an application for Clearance Certificate to commence earthworks

4. Obtain Clearance Certificate to commence earthworks from PUB

5. Engage ECO or trained person in ECM

6. Implement QECP’s endorsed ECM plan before commencement of works

a. Erosion Control 1) Minimise exposure of bare surface by paving up, erosion control blankets or scheduling works in phases, etc

b. Sediment Control 1) perimeter silt fence 2) perimeter cut­off drains 3) silt trap 4) storage tanks / ponds 5) treatment system etc

During Construction

1. Monitor and Maintain the ECM to ensure effectiveness

2. Engage QECP to : a) Set up site monitoring and management system for ECM b) review in tandem with progress of works and implement the revised ECM

accordingly

3. Submit weekly reports of ECM at site to QECP

4. provide continuous monitoring and recording system at discharge point before public drain

5. cover up the active work surfaces with canvas sheet during rain or at the end of the workday

6. Make available to PUB Officers at all times of visits the followings:

i. QECPs endorsed ECM plan (latest revision)

ii. Records of inspections by QECP and ECO

iii. Continuous record

Before Completion 1. Provide / establish finishing surfaces (close turfing, concrete paving, road surfaces etc)

2. Obtain QECP’s approval before ECM is removed

(B) Developer and Professional

Each sector of the construction industry plays a critical role in implementing an effective earth control measures (ECM) at construction sites. Please refer to Annex 1 for fuller details of the roles. The key roles are summarised below:­

(1) Developer / QP to include sample specifications and itemised BQ for ECM (see Annex 2) in tender document before commencement of works.

(2) QECP to advise developer / QP and plan, design and monitor effective ECM.

*QECP – Qualified Erosion Control Professional

3. Implementation of an Effective ECM

An effective earth control measure (ECM) must comprise 2 aspects: (a) Erosion Control ­ to minimise bare earth surfaces (b) Sediment Control ­ to contain, storage and treat silt sediments and shall comply with Clause 6.3 of the Code of Practice on Surface Water Drainage (See Chapter 7)

(A) Erosion Control

It is much easier and more cost­effective to prevent erosion than to trap sediments after erosion has taken place. With proper planning, a site should not have more than 0.1 ha of bare surface at any one time.

The following are some good ECM management practices to minimise erosion by ensuring minimum bare earth surfaces at all time:

Scheduling of works:

1 to properly sequence and schedule the earthworks / demolition / construction works in stages and progressively to minimise bare surfaces.

2 to minimise site disturbance by keeping site clearance works to a minimum by retaining as much of the existing vegetation as possible.

3 to establish final surface (by close turfing, concrete paving, road surfaces etc) immediately.

No bare surfaces:

1 to pave up the bare surfaces and all construction access by concrete or milled waste or other suitable materials.

2 to protect the bare slopes by close­turfing, cementitious spray / grouting or erosion control blanket.

3 to protect the earth stockpiles by erosion control blanket. 4 to cover up the active work surfaces by canvas sheet during rain or before

work stop at the end of workday. 5 to turf up the bare surfaces immediately in an earthwork / demolition work if

there is no subsequent construction activities.

(B) Sediment Control

After achieving minimum bare earth surfaces, sediment control facilities must be put in place to capture the sediments washed down from the construction sites. Some of these sediment control measures and facilities which must be in place before the works start shall include the following:

Containment:

1 to provide concrete­lined cut­off drains (minimum C7 precast channel) along the perimeter of the construction sites.

2 to provide silt fence properly installed and embedded onto the ground along the perimeter cut­off drains (between the construction site and the cut­off drains).

Storage:

1 to provide sedimentation basins of adequate size and sufficient numbers along the perimeter cut­off drains and before the discharge points into public drain.

2 to provide storage tank, reservoir of adequate size and sufficient numbers to temporarily store / contain rainwater before treatment.

Treatment:

1 to provide treatment units or coagulant units to treat silty water before discharge into public drain.

(C) Maintenance and Review

1 to maintain all erosion and sedimentation control facilities to ensure effectiveness at all time.

2 to review ECM regularly as the work progresses.

4. Submission Requirements for ECM Note: The earth control measure (ECM) is meant for the control of silty discharge due to rain water. Other waste water (slurry water, bentonite etc) due to construction activities such as piling or tunneling work should be separately treated

(A) During Planning Stage

The owner / developer should take note of the standard clause for the ECM requirement before obtaining DC clearance / approval

Earth Control Measures: Effective erosion and sediment control measures shall be provided by the developer / owner and the QP shall advise his developer / owner to provide such effective measures and facilities with inputs from Qualified Erosion Control Professional (including site management system and perimeter cut­off drain, silt traps, storage ponds, treatment plants, etc) to ensure clean discharge that complies with the statutory requirement. The proposed erosion and sediment control measures shall be submitted by a Qualified Erosion Control Professional (QECP) to Public Utilities Board for approval before commencement of works. All affected watercourses shall be desilted and cleared until completion of work. For reference, the information can be found in the website http://www.pub.gov.sg/ECM.

(B) Before commencement of work

The Contractor shall apply for a Clearance Certificate to commence works (which will require ECM) together with the proposed erosion and sediment control measures (prepared and endorsed by a QECP) to PUB.

The earth control measures shall comply with the requirements stipulated in Clause 6.3 of the “Code of Practice on Surface Water Drainage” (Posted at PUB website address http://www.pub.gov.sg/downloads/PR6.aspx).

(C) During Construction Stage

The Contractor shall submit the ECM proposal duly endorsed by his QECP to PUB and carbon copied to the owner / developer as follows:

1 Before Work Commences ­ to submit the ECM proposal indicating that:

a minimum bare surfaces will be ensured according to the construction activities in each phase.

b effective sediment control facilities (Including storage and treatment facilities) will be implemented

c a system of ECM as indicated in (a) and (b) above will be in place before work commence

d Clearance Certificate (See (B) above) to commence earthworks is obtained

2 During Work ­ to revise and resubmit the ECM proposals according to each phase of the construction activities indicating that:

a minimum bare surfaces will be ensured according to the construction activities in each phase.

b effective sediment control facilities (Including storage and treatment facilities) will be implemented

c a system of ECM as indicated in a and b above will be revised and put in place to control silty discharge for each phase

3 Upon Work Completion ­ to confirm that all the site activities have been completed and the ECM can be removed.

(D) Before Work Completion

The contractor shall inform PUB that ECM will be removed based on QECP’s recommendation / approval.

5. Checklist of Erosion and Sediment Control Note: The earth control measure (ECM) is meant for the control of silty discharge due to rain water. Other waste water (slurry water, bentonite etc) due to construction activities such as piling or tunneling work should be separately treated

(A) Checklist of Erosion Control

No bare surfaces √ To protect bare slopes and stockpiles with close turfing

or erosion control blankets or lean concrete

√ To establish final surface / turfing quickly

√ To cover up active work surfaces by canvas sheet during rain or before work stop at the end of workday

Scheduling of works √ To minimise bare earth surfaces to 0.1ha at any one time

√ To sequence and schedule earthworks / demolition or construction works in stages and progressively with subsequent activities

√ To pave up all construction access and bare surfaces with concrete, milled waste, etc

√ To minimize site disturbance by keeping site clearance works to a minimum by retaining as much of the existing vegetation as possible.

√ To establish final surface / turfing quickly

(B) Checklist of Sediment Control

Containment √ To provide perimeter lined cut­off drains

√ To provide perimeter silt fences along perimeter cut­off drains

√ To provide turbidity curtain for work alongside rivers & waterways

√ To protect earth slopes/surfaces with closed turfing, milled waste, concrete, erosion control blankets, polythene sheets or other suitable materials

Storage √ To provide adequate size and number of sedimentation

sumps or storage tanks before treatment of silty water

√ To provide adequate size and number of sedimentation sumps or storage tanks before discharge and along the perimeter cit­off drain

Treatment √ To provide treatment unit / coagulant unit to treat silty

water before discharge

Maintenance √ To maintain sediment control facilities at least once a

week and after every storm event

(C) Regular Review

√ To review ECM plan with QECP as work progresses

√ To remove ECM only at the end of work and as advised by QECP

6. Bad & Good Practices at Construction Sites

NO Silty Discharge

6. Bad & Good Practices at construction sites

NO BARE SURFACE

Without turfing With turfing

Without ECB With ECB

Without Lean Concrete With Lean concrete

List of technology providers in chapter 8

6. Bad & Good Practices at construction sites

Silt Fence & Perimeter Drain

Silt fence not properly embedded resulting in gaps below the fence

& Silt fence installed on the wrong side. It should be installed to trap the silt from

the worksite

Silt fence firmly embedded in ground and installed in between cut­off drain

and worksite

List of technology providers in chapter 8

6. Bad & Good Practices at construction sites

Silt Trap

Inadequate silt trap resulted in silty water discharges onto adjacent public

place

Silt trap properly designed with the usage of polymer block & geotextiles. (note: sand or granite chip as filter is not

accepted)

List of technology providers in chapter 8

6. Bad & Good Practices at construction sites

Silty Water Treatment System

List of technology providers in chapter 8

6. Bad & Good Practices at construction sites

Turbidity Curtain

List of technology providers in chapter 8

7. Legislation and Code of Practices

The following legislation and requirements pertaining to the control of erosion and sediment are highlighted:

THE SEWERAGE AND DRAINAGE ACT, CAP. 294

Works affecting storm water drainage system Section 26(1) ­ No person shall carry out or cause to be carried out any works which will affect any storm water drainage system, drain or drainage reserve, directly or indirectly, without obtaining in respect of those works, a clearance certificate or approval of the Board.

Section 26(2) ­ Where any work has been carried out in contravention of subsection 26(1), the Board may by Notice in writing require the person who carried out the works, the owner or occupier of any premises in respect of which the works were carried out to carry out such works as the Board thinks necessary within such time as may be specified in the Notice.

Default in compliance with notice

Section 41(1) ­ Where a person on whom a Notice under section … 26 … is served fails to comply with the notice within the time specified in the Notice, he shall be guilty of an offence and shall be liable on conviction to a fine not exceeding $20,000.

SEWERAGE AND DRAINAGE (SURFACE WATER DRAINAGE) REGULATIONS REVISED EDITION 2001

Prohibition of discharge of silt, etc. into storm water drainage system

Regulation 4(1) ­ No person shall discharge or cause or permit the discharge into the storm water drainage system of Total Suspended Solids in concentrations greater than 50 milligrams per litre of the discharge.

Regulation 4(2) ­ Every person carrying out earthworks or construction works shall comply with the Code of Practice and in particular with the following requirements:

a) earth control measures shall be provided and maintained in accordance with the Code of Practice

b) runoff within, upstream of and adjacent to the work site shall be effectively drained away without causing flooding within or in the vicinity of the work site.

c) all earth slopes shall be set outside a drainage reserve; d) all earth slopes adjacent to any drain shall be closed turfed;

and e) adequate measures shall be taken to prevent any earth,

sand, topsoil, concrete, debris or any other material to fall or washed into the storm water drainage system from the stockpile thereof.

SEWERAGE AND DRAINAGE (SURFACE WATER DRAINAGE) REGULATIONS REVISED EDITION 2003

Penalty

Regulation 6 ­ Any person who contravenes or fails to comply with any provision of these Regulations shall be guilty of an offence and shall be liable on conviction to a fine not exceeding $5,000 and, in the case of a continuing offence, to a further fine of $500 for every day or part thereof during which the offence continues after conviction.

CODE OF PRACTICE ON

SURFACE WATER DRAINAGE (Fifth Edition ­ Mar 2000)

Addendum No. 3 ­ Aug 2006

This addendum shall be read in conjunction with the Code of Practice on Surface Water Drainage (Fifth Edition ­ Mar 2000) and shall form part of the Code of Practice.

S/No. Part /Page No

Amendments /corrections

1 2 Define “Qualified Erosion Control Professional”

2 18 Delete Clauses 6.3.1 to 6.3.4 and Substitute with Clauses 6.3.1 to 6.3.12

(1) Define “Qualified Erosion Control Professional”

Terminology "Qualified Erosion Control Professional" (QECP) means a Professional Engineer who is registered under the Professional Engineers Act Chapter 253, has in force a practising certificate issued under that Act, and has satisfactorily completed a specialized professional course in erosion and sediment control.

(2) Delete Clauses 6.3.1 to 6.3.4 and Substitute with Clauses 6.3.1 to 6.3.12

6.3 Earth Control Measures

6.3.1 Water Quality Parameters to be Complied with The discharge from any construction / earthwork sites into storm water drainage system shall not contain Total Suspended Solids (TSS) in concentrations greater than, or turbidity exceeding, the prescribed limits under Regulation 4(1) of the Sewerage and Drainage (Surface Water Drainage) Regulations.

6.3.2 Minimal or No Discharge A construction / earthwork site should practice recycling of water. The recycled water could be used for non­potable purposes in order to minimise discharge into the stormwater drainage systems.

6.3.3 ECM Specifications in Tenders Developers / owners and Qualified Persons should include the earth control measures (ECM) specifications and schematic or conceptual ECM plans in the tender documents and allow for the cost of ECM in the tenders.

6.3.4 Permit to start Earthworks The site operator / contractor shall obtain a written permission (or a clearance certificate) from Public Utilities Board before the commencement of any earthwork.

6.3.5 Submission of ECM proposal before commencement of works Before commencement of works, the site operator / owner shall engage a Qualified Erosion Control Professional (QECP) to plan and design a system of earth control measures (ECM) to meet the requirements cited in Clause 6.3.1.

The site operator / owner shall submit the detailed ECM proposal, endorsed by his QECP, to the Public Utilities Board for record, prior to the commencement of works. The ECM proposals (with calculations) shall include a plan (a typical plan is as shown in Drawing No.9)

6.3.6 Design Criteria of ECM The ECM shall be designed to cope with a minimum design rainfall intensity of a return period of 1 in 2 years storm.

6.3.7 ECM to be installed before commencement of work The ECM shall be installed by the site operator / contractor according to the endorsed plans and the completed ECM at site shall be approved by the QECP before commencement of construction and earthworks

6.3.8 General Guidelines for Effective ECM An effective ECM requires 2 components which shall include, but is not limited to, the following minimum measures in order to meet the legal requirements cited under Regulation 4(1) of the Sewerage and Drainage (Surface Water Drainage) Regulations:

(A) Erosion Control Measures

The erosion control measures shall minimise the extent and duration of any exposed / bare / erodible surfaces by:

a. Proper Work Sequencing ­ Adopting proper construction staging and work sequencing will help to ensure that no large bare / erodible surfaces are exposed for a long duration of time.

b. Covering up of all bare / erodible surfaces ­ All bare surfaces (including earth stockpiles) shall be by concrete­lining, concrete­paving, milled waste, erosion control blankets, close turfing or other suitable materials. Accesses within the site and at exit / entrance as well as the surfaces where site facilities (such as office, fabrication and storage yards) shall be paved. For those work areas, they shall be covered by canvas sheets, tarpaulin sheeting or other suitable materials during rains or before work stops every day.

c. Progressive and timely revegetation and stabilisation – This is to ensure that all bare surfaces are restored immediately upon completion of work at every stage.

If a construction site has very little bare / erodible surfaces, the operator / contractor will have less difficulty in containing and treating the silty discharges as described in Clause 6.3.8 (B) below. For those areas within a

construction site which have been paved / covered and will not cause silty discharge, it is possible to drain these areas directly into the storm water drainage system without treatment.

(B) Sediment Control Measures

The sediment control measures shall trap, contain and treat the silty discharges from within a construction / earthworks site (including rain, runoff, water from washbay, underground water at basement, etc) by providing:

a. Perimeter Cut­off Drain – Perimeter cut­off drains shall be concrete­lined and adequate to capture all runoff from the site to prevent overflow onto adjacent properties.

b. Perimeter Silt Fence – Silt fences shall be erected along the perimeter cut­off drain (between the construction site and perimeter cut­off drain). The silt fence is to be embedded firmly into the ground and made from an approved geotextile filter fabric or equivalents to capture the sediment from stormwater runoff. The sediment built­up behind the silt fence must be regularly removed.

c. Intermediate Silt Trap – Intermediate silt traps of suitable size shall be installed at regular intervals along the perimeter lined cut­off drain. Within the intermediate silt traps, suitable geotextile filter fabric or equivalents shall be installed across the full depth and width and / or coagulation­assistance materials shall be placed. Silt traps relying primarily on hardcore, granite chips or sands for filtration, are not acceptable.

d. Sedimentation Basin or Storage Pond / Tank ­ Before silty discharge leaves the site, the silt and sediments shall be separated from the water. This can be achieved by either:

i. in a sedimentation basin / pond (which will take days for settlement to take place and a large basin volume), or

ii. through a treatment system–cum–storage tank.

The basin / tank shall have a storage capacity to cope with the volume of water from a rain based on a minimum design return period of 1 in 2 years storm.

e. Treatment System – If the design of a sedimentation basin cannot meet the TSS requirement, then other suitably­sized treatment system shall be installed to treat all silty discharge from construction and earthwork sites. The treated effluent could be recycled for non­potable use.

f. Turbidity Curtains ­ For works in or adjacent to water bodies, such as canals, rivers, sea or in a reclamation work, turbidity curtain(s) shall be installed along all the exposed slopes / riverbanks. The silty discharge

trapped within the turbidity curtain shall be allowed to be settled or treated, and the settled silt removed

g. Wheel wash – the waters used to wash the wheels of the trucks / vehicles shall not be discharged into stormwater drainage system at any time. The silty water within the wheel wash basin shall be connected to the sedimentation basin / treatment system. The silt collected at the bottom of the wheel wash shall be removed.

6.3.9 Review of ECM during Contract duration The site operator/ contractor shall ensure that the ECM designed and installed shall be continuously reviewed by the QECP for every stage of the construction and earthworks. The ECM shall remain effective throughout the whole duration of works. The site operator / contractor shall add or amend the ECM at site according to the design of the QECP.

6.3.10 Maintenance of ECM during Contract duration The site operator / contractors shall operate and maintain the ECM regularly to ensure the ECM remains effective throughout the whole duration of works. This may involve replacing of silt fences and erosion control blankets or re­paving of concrete surfaces or replacing of membrane module or polymers blocks.

6.3.11 Monitoring of Discharge during Contract duration The site operator / contractor shall monitor the TSS and turbidity of the discharge before the discharge enters the storm water drainage system. The site operator / contractor shall submit regular reports (including photographic and monitoring records) of the site ECM as well as those for discharge quality to the Public Utilities Board over the whole duration of the project.

6.3.12 Removal upon Completion The ECM shall not be removed before the completion of work. The site operator/ owner shall inform Public Utilities Board prior to removal of the ECM on completion of the project.

8. Listing of ECM products, services and technologies providers

(For updated list of suppliers, please visit ECM website – www.pub.gov.sg/ECM)

Erosion Control Blankets • Abacus Corp, Belton Industries Inc, FNW, Kingfibre & Soilguard • CHT­Natural Solutions, email : yufong@starhub.net.sg • Fibromat; Fibrotag, email: walltag@singnet.com.sg • Mirafi Geosynthetics http://www.mirafi.com/products/products_index.html • North American Green : http://www.nagreen.com

Indirect Screening for Silt / Debris Control • CDS Technologies : http://www.cdstech.com • Rocla : http://www.pipe.rocla.com.au • Stormceptor : http://www.rinkerstormceptor.com

Polymer • CCM Singapore Pte Ltd, Tel : 64685468 • Trident Chemicals Enterprise, Tel : 67266188

Silt Fence • AbacusCorp, email : abetrad@singnet.com.sg • Geotag Silt Fence, email : walltag@singnet.com.sg • Mirafi Geosynthetics Products : http://www.mirafi.com/products_index.html • Permathere : http://www.permathene.co.nz/htm/silt.htm • Southeast Environment Services, Inc : http://www.southwesrenvironment.com • Tencate, email : m.sim@tencate.com

Silt Water Treatment System • Flexi Systems, email: flexi_system@yahoo.com.sg • Glowtech, Tel: 62552866 • KBI Contracts & Marketing Pte Ltd, email: yufong@starhub.net.sg • Sam McCoy Engineering P/L: http://www.sammccoy.com • Singaport Cleanseas P/L, email: victorp@ultra­flo.com.sg • SiltTreat, email: chengkf@pacific.net.sg • WETSEP, email: sales@scottvickers.com.sg

Turbidity Curtain • Elastec American Marine Inc : http://www.elastec.com/curtains.html • Geotag Silt / Turbidity Curtain, email: walltag@singnet.com.sg • Mentanza Pty Ltd : http://www.mentanzapl.com/silt_screens.htm • Permathene : http://www.permathene.co.nz/turbidity.htm

Annexes

Annex 1 ­ Roles of Construction Industry

Annex 2 ­ Sample Specifications and Itemised BQ for ECM

Annex 3 ­ Schematic Drawing for ECM at Construction Sites

Annex 4 ­ TSS Samples (50mg/l)

Annex 1

Roles of construction industry

ROLES Project

Development

Process Owner / Developer / Qualified Person

QECP (Engaged by Owner / Developer)

(I) Planning & Design

1. Qualified Person could consult PUB on the need to engage QECP for proposals that involve minimium earth disturbance in the early stage (i.e. during DC Clearance) Qualified Person to advise the owner / developer accordingly.

2. Developer to engage QECP for preliminary ECM & specifications

3. Developer to endorse BP for compliance with ECM as specified in Code of Practice on Surface Water Drainage (Latest Edition)

1. Conduct site assessment, plan, design and submit preliminary ECM to PUB for record

2. Advise Owner / Developer / Qualified Person to :

a. include ECM specifications (incl the preliminary ECM plan for project and allow for costs) ­ (see Annex 2 for sample specification and itemised BQ)

b. refer to ECM website @ www.pub.gov.sg/ECM

(II) Tender

1. Developer / Qualified Person to evaluate preliminary ECM plan in tender submission

2. Qualified Person to submit successful Contractor’s particulars to PUB

1. Stipulate ECM requirements according to site conditions of the project and allow tenderers to price for them in the tender document

2. Provide advice / evaluation on submitted preliminary ECM plan and method statements received from tenderers

Contractor QECP (Engaged by Contractor)

(May or may not be the same QECP of Developer / Owner above)

(III) Before

Commencement of works

1. Engage QECP for detailed ECM

2. Provide information on topography, soil, construction work and schedule, site facilities, etc to QECP

3. Submit ECM plan prepared and endorsed by both QECP and Contractor to PUB together with an application for Clearance Certificate to commence earthworks

4. Obtain Clearance Certificate to commence earthworks from PUB

5. Engage ECO or trained person in ECM

6. Implement QECP’s endorsed ECM plan before commencement of works

a. Erosion Control 1 Minimise exposure of bare

surface by paving up, erosion control blankets or scheduling works in phases, etc

b. Sediment Control 1 perimeter silt fence 2 perimeter cut­off drains 3 silt trap 4 storage tanks / ponds 5 treatment system etc

1. Prepare a detailed ECM plan (basing on information provided on topography, soil, construction work and schedule, site facilities, etc) for all phases of the project for submission to PUB. QECP may be required to make presentation to PUB.

2. Advise Contractor to submit ECM plan to PUB and obtain Permit or Clearance Certificate to commence earthwork before commencement of works

3. Advise Contractor on setting up of a monitoring and control system at site, including:

a. appointment of and brief Environmental Control Officer or trained person in ECM on the ECM plan and checklist

b. monitoring the installation of ECM to QECP’s specifications and ensuring its effectiveness

c. scheduling of maintenance of ECM and inspections

(IV) During

Construction

1. Monitor, Maintain the ECM to ensure effectiveness

2. Engage QECP to a) Set up site monitoring and management system for ECM

b) review in tandem with progress of works and implement the revised ECM accordingly

3. Submit weekly reports of ECM at site to QECP

4. provide continuous monitoring and recording system at discharge point before public drain

5. cover up the active work surfaces with canvas sheet during rain or at the end of the workday

6. Make available to PUB Officers at all times of visits the followings:

i. Endorsed ECM plan

ii. Records of inspections by QECP and ECO

iii. Continuous record

1. Advise contractor on the effectiveness of the site monitoring and management systems.

2. Review ECM in tandem with progress of works

3. Oversee the keeping of ECM inspections records.

4. Requiring Contractor’s ECO or trained person in ECM to submit weekly reports for checking and compilation.

5. Inform PUB of any non­compliances of ECM plan

(V) Before

Completion

1. Provide / establish finishing surfaces (close turfing, concrete paving, road surfaces etc)

2. Obtain QECP’s approval before ECM is removed

1. Ensure ECM is removed only after completion of all works

CIJC –PUB Task Force’s Visit to Model ECM Site (22 Apr 2006)

Annex 2 SAMPLE SPECIFICATIONS FOR EARTH CONTROL MEASURES (Revision 3 ­ Sep 06)

1. The Contractor shall be responsible for preventing silt from being washed into public drains by implementing effective Earth Control Measures (ECM) for the construction site to meet the requirements under the latest Sewerage and Drainage Act Cap 294. (Information on ECM requirements can be found in the Code of Practice on Surface Water Drainage and the website www.pub.gov.sg/ECM). The contractor shall note that the ECM are for the containment and treatment of silty discharges due to the impact of rainwater. ECM are not meant for the treatment of wastewater due to construction activities (such as slurry from tunnelling, pipe­jacking and bore­piling works) which shall be treated to comply with the requirements under Environmental Pollution Control Act (Chapter 94A).

2 In his tender submission, the Contractor shall submit his schematic ECM plans of the construction site for the whole duration of the contract period taking into account the different phases of construction activities. He shall also provide the name of the Qualified Erosion Control Professional (QECP) who will be endorsing the ECM plan after the tender is awarded. These schematic ECM plans shall make the Contractor aware of the ECM requirements and the cost to implement an effective ECM. Notwithstanding the submission of these schematic ECM plans, the Contractor shall deem to have separately priced for the ECM in the contract sum.

3 Before construction works commence on site, the Contractor shall engage a QECP to plan and design the ECM, and he shall install the ECM according to the QECP's design. The ECM plan and design shall be submitted 1 week after the award of the contract. During the course of the construction works, the Contractor together with his QECP shall review the ECM proposal regularly to meet the changing needs of the construction activities. The Contractor shall improve the ECM as advised by his QECP. The planning and design of the ECM shall meet the minimum requirements stipulated and in accordance to the Code of Practice on Surface Water Drainage.

4 The Contractor shall maintain the ECM for the whole duration of the contract to ensure that it is effective at all times. Proper records detailing the maintenance works, supported by dated photographs, shall be kept by the Contractor for verification.

5 The Contractor shall not remove the ECM until all works are completed and upon the advice of his QECP.

6 The Contractor shall submit the ECM proposal duly endorsed by his QECP to PUB for records. The proposed ECM shall consist of the following four parts:

I. Project Particulars The following information shall be provided under the Project Particulars:

(a) Project description (b) Name and address of site occupier; (c) Site area and contract period; (d) Location map and site plan.

II. Erosion Control Plan (described in 7) III. Sediment Control Plan (described in 8) IV. Site ECM Management System (descried in 9)

7 During construction, the Contractor shall minimize the formation of bare surfaces under the ECM's Erosion Control Plan. The Plan shall depict graphically the activities, including sequence of work, type and duration for each phase of construction activities to include the following measures to:

(a) sequence and schedule of the earthworks I demolition works in stages and progressively with the subsequent construction activities and building works.

(b) minimise site disturbance by keeping site clearance works to a minimum by retaining as much of the existing vegetation as possible.

(c) pave up the bare surfaces and all construction access by concrete or milled waste or other suitable materials.

(d) protect the bare slopes with close­turfing, concrete grouting, or erosion control blanket.

(e) protect the earth stockpiles with erosion control blanket. (f) restore ground cover over disturbed areas, which are or have become

bare, as soon as possible. (g) cover up the active work surfaces with canvas sheet during rain or at the

end of the workday.

8 The Contractor shall put in place the ECM's Sediment Control Plan, which aims to capture the sediments washed down from the construction sites. Some of these sediment control measures and facilities, which must be in place before the works start, shall include but not limited to the following:

(a) concrete­lined cut­off drains (minimum C7 precast channel) along the perimeter of the construction sites.

(b) silt fence properly installed and embedded onto the ground along the perimeter cut­off drains (between the construction site and the cut­off drain).

(c) sedimentation basins or any other sediment filtering or settling system of adequate size and sufficient numbers along the perimeter cut­off drain and before the discharge points into public drain.

(d) a storage basin / tank may be required to temporarily store the large amount of rainwater falling on to the whole site before treatment.

(e) a treatment system to treat silty discharge shall be provided before the discharge points into public drain.

(f) turbidity curtains shall be installed along all the exposed slopes / riverbanks for works in or adjacent to water bodies, such as canals, rivers, sea or in a reclamation work. The silty discharge trapped within the turbidity curtain shall be allowed to be settled / treated and removed.

9 The contractor, shall at the advice of his QECP, put in place a site monitoring and reporting system including but not limited to the following:

(a) Daily ECM inspection report by the QECP appointed site personnel (b) Regular site inspection by the QECP (c) Continuous monitoring and recording system shall be installed at the

discharge point (after ECM) before public drain

10 The QECP shall submit full basis of design back up with design calculations to show clearly how the perimeter cut­off drains, silt fence, sedimentation basins, storage basin / tank and treatment system are designed and sized as well as how such design will effectively filter off silt and allow only clean water to discharge into public drains. The QECP shall also submit the design specifications on the treatment system which can effectively treat the silty discharge from the construction site. The intensity of a one­in­two year storm should be adopted for the proposed design.

SAMPLE ITEMISED BQ FOR EARTH CONTROL MEASURES:

S/No Description Qty Unit Rate Amount ($)

A Allow for engaging a Qualified Erosion Control Professional to design, review and submit Earth Control Measures Proposals to the full satisfaction of the SO. All as specified, throughout the whole duration of works.

­ Item ­

B Allow for the implementation and maintenance of the Erosion Control Plan; all as specified.

­ Item ­

C Allow for the implementation and maintenance of Sediment Control Plan (including the provision of the storage and treatment facilities); all as specified.

­ Item ­

D Allow for site reporting and monitoring system throughout the whole duration of contract.

­ Item ­

TOTAL TO SUMMARY OF TENDER

Annex 3

Schematic Drawing for ECM at Construction Sites

Annex 4

Water sample with various Total Suspended Solids (TSS) Readings.

5000 mg/l 500 mg/l 250 mg/l 50 mg/l

1 st edition ­ 2001

2 nd edition – December 2003

3 rd edition – September 2006