M 41-10 Page 8-1Division 8 Miscellaneous Construction
8-01 Erosion Control and Water Pollution Control
8-01.1 Description
This Work consists of furnishing, installing, maintaining, removing and disposing of best management practices (BMPs), as defined in the Washington Administrative Code (WAC) 173-201A , to manage erosion and water quality in accordance with these Specifications and as shown in the Plans or as designated by the Engineer. The Contracting Agency may have a National Pollution Discharge Elimination System Construction Stormwater General Permit (CSWGP) as identified in the Contract Special Provisions. The Contracting Agency may or may not transfer coverage of the CSWGP to the Contractor when a CSWGP has been obtained. The Contracting Agency may not have a CSWGP for the project but may have another water quality related permit as identified in the Contract Special Provisions or the Contracting Agency may not have water quality related permits but the project is subject to applicable laws for the Work. Section 8-01 covers all of these conditions.
8-01.1(1) Definitions
1.pH Affected Stormwater
a.Stormwater contacting green concrete (concrete that has set/stiffen but is still curing), recycled concrete, or engineered soils (as defined in the Construction Stormwater General Permit (CSWGP)) as a natural process
b.pH monitoring shall be performed in accordance with the CSWGP, or Water Quality Standards (WQS in accordance with WAC 173-201A (surface) or 173-200C (ground)) when the CSWGP does not apply
c.May be neutralized and discharged to surface waters or neutralized and infiltrated
2.pH Affected Non-Stormwater
a.Conditionally authorized in accordance with CSWGP Special Condition S.1.C., uncontaminated water contacting green concrete, recycled concrete, or engineered soils (as defined in the CSWGP)
b.Shall not be categorized as cementitious wastewater/concrete wastewater, as defined below
c.Shall be managed and treated in accordance with the CSWGP, or WQS when the CSWGP does not apply
d.pH adjustment and dechlorination may be necessary, as specified in the CSWGP or in accordance with WQS when the CSWGP does not apply
e.May be neutralized, treated, and discharged to surface waters or neutralized and infiltrated in accordance with the CSWGP, with the exception of water-only shaft drilling slurry. Water-only shaft drilling slurry may be treated, neutralized, and infiltrated but not discharged to surface waters (refer to Special Conditions S1.C. Authorized Discharges and S1.d Prohibited Discharges of the CSWGP)
3.Cementitious Wastewater/Concrete Wastewater
a.All water that comes into contact with fine cementitious particles or slurry; water used in the production, placement and/or clean-up of cementitious products; water used to cut, grind, wash, or otherwise modify cementitious products Page 8-2 M 41-10
8-01 Erosion Control and Water Pollution Controlb. When water, including stormwater, commingles with cementitious wastewater/
concrete wastewater, the resulting water is considered cementitious wastewater/ concrete wastewater and shall be managed to prevent discharge to waters of the State, including ground water
c.CSWGP Examples include: water used for or resulting from concrete truck/ mixer/pumper/tool/chute rinsing or washing, concrete saw cutting and surfacing (sawing, coring, grinding, roughening, hydro-demolition, bridge and road surfacing)
d.Cannot be neutralized and discharged or infiltrated
8-01.2 Materials
Materials shall meet the requirements of the following sections: Corrugated Polyethylene Drain Pipe 9-05.1(6) Quarry Spalls 9-13 .1(5) Seed 9-14.3 Fertilizer 9-14.3 Mulch and Amendments 9-14.5 Tackifier 9-14. 5(7) Erosion Control Devices 9-14.6 Plant Materials 9-14.7 Construction Geotextile 9-33 Recycled concrete, in any form, shall not be used for Work defined in Section 8-01 .
8-01.3 Construction Requirements
8-01.3(1) General
Adaptive management shall be employed throughout the duration of the project for the implementation of erosion and water pollution control permit requirements for the current condition of the project site. The adaptive management includes the selection and utilization of BMPs, scheduling of activities, prohibiting unacceptable practices, implementing maintenance procedures, and other managerial practices that when used singularly or in combination, prevent or reduce the release of pollutants to waters of the State. The adaptive management shall use the means and methods identified in this section and means and methods identified in the Washington State Department of Transportation’s Temporary Erosion and Sediment Control Manual or the Washington State Department of Ecology’s Stormwater Management Manuals for construction stormwater. The Contractor shall install a high visibility fence along the lines shown in the Plans or as instructed by the Engineer. Throughout the life of the project, the Contractor shall preserve and protect the delineated preservation area, acting immediately to repair or restore all damaged or removed high visibility fencing. All discharges to surface waters shall comply with surface water quality standards as defined in Washington Administrative Code (WAC) Chapter 173-201A . All discharges to groundwater shall comply with groundwater quality standards WAC Chapter 173-200 . The Contractor shall comply with the CSWGP when the project is covered by the CSWGP. Work, at a minimum, shall include the implementation of:
1.Sediment control measures prior to ground disturbing activities to ensure all discharges from construction areas receive treatment prior to discharging from the site.
2.Flow control measures to prevent erosive flows from developing. M 41-10 Page 8-3 Erosion Control and Water Pollution Control 8-013. Water management strategies and pollution prevention measures to prevent contamination of waters that will be discharged to surface waters or the ground.
4.Erosion control measures to stabilize erodible earth not being worked.
5.Maintenance of BMPs to ensure continued compliant performance.
6.Immediate corrective action if evidence suggests construction activity is not in compliance. Evidence includes sampling data, olfactory or visual evidence such as the presence of suspended sediment, turbidity, discoloration, or oil sheen in discharges. To the degree possible, the Contractor shall coordinate this Work with permanent drainage and roadside restoration Work the Contract requires. Clearing, grubbing, excavation, borrow, or fill within the Right of Way shall never expose more erodible earth than as listed below: Western Washington (West of the Cascade Mountain Crest) May 1 through September 30 17 Acres October 1 through April 30 5 Acres Eastern Washington (East of the Cascade Mountain Crest) April 1 through October 31 17 Acres November 1 through March 31 5 Acres The Engineer may increase or decrease the limits based on project conditions. Erodible earth is defined as a surface where soils, grindings, or other materials may be capable of being displaced and transported by rain, wind, or surface water runoff. Erodible earth not being worked, whether at final grade or not, shall be covered within the specified time period (see the table below) BMPs for erosion control. Western Washington (West of the Cascade Mountain Crest) October 1 through April 30 2 days maximum May 1 to September 30 7 days maximum Eastern Washington (East of the Cascade Mountain Crest) October 1 through June 30 5 days maximum July 1 through September 30 10 days maximum When applicable, the Contractor shall be responsible for all Work required for compliance with CSWGP including annual permit fees. If the Engineer, under Section 1-08.6 , orders the Work suspended, the Contractor shall continue to comply with this division during the suspension.
8-01.3(1)A Submittals
8-01.3(1)A1 Temporary Erosion and Sediment Control Plan
Temporary Erosion and Sediment Control (TESC) Plans consist of a narrative section and plan sheets that meets Ecology’s Stormwater Pollution Prevention Plan (SWPPP) requirement in the CSWGP. For projects that do not require a CSWGP but have the potential to discharge to surface waters of the state, an abbreviated TESC plan shall be used, which may consist of a narrative and/or plan sheets and shall demonstrate Page 8-4 M 41-10
8-01 Erosion Control and Water Pollution Controlcompliance with applicable codes, ordinances and regulations, including the water quality
standards for surface waters, Chapter 173-201A of the Washington Administrative Code (WAC) and water quality standards for groundwaters in accordance with Chapter 173-200 WAC . The Contractor shall either adopt the TESC Plan in the Contract or develop a new TESC Plan. If the Contractor adopts the TESC Plan in scenarios in which the CSWGP is transferred to the Contractor, the Contractor shall modify the TESC Plan to match the Contractor’s schedule, method of construction, and to include all areas that will be used to directly support construction activity such as equipment staging yards, material storage areas, or borrow areas. TESC Plans shall include all high visibility fence shown in the Plans. All TESC Plans shall meet the requirements of the current edition of the WSDOT Temporary Erosion and Sediment Control Manual M 3109 and be adaptively managed throughout construction based on site inspections and required sampling to maintain compliance with the CSWGP, or WQS when no CSWGP applies. The Contractor shall develop a schedule for implementation of the TESC work and incorporate it into the Contractor’s progress schedule. The Contractor shall submit their TESC Plan (either the adopted plan or new plan) as Type 2 Working Drawings. At the request of the Engineer updated TESC Plans shall be submitted as Type 1 Working Drawings.
8-01.3(1)B Erosion and Sediment Control (ESC) Lead
The Contractor shall identify the ESC Lead at the preconstruction discussions and in the TESC Plan. The ESC Lead shall have, for the life of the Contract, a current Certificate of Training in Construction Site Erosion and Sediment Control from a course approved by the Washington State Department of Ecology. The ESC Lead must be onsite or on call at all times throughout construction. The ESC Lead shall be listed on the Emergency Contact List required under Section 1-05.13(1) . The ESC Lead shall implement the TESC Plan. Implementation shall include, but is not limited to:
1.Installing, adaptively managing, and maintaining temporary erosion and sediment control BMPs to assure continued performance of their intended function. Damaged or inadequate BMPs shall be corrected immediately.
2.Updating the TESC Plan to reflect current field conditions.
3.Discharge sampling and submitting Discharge Monitoring Reports (DMRs) to Ecology in accordance with the CSWGP.
4.Develop and maintain the Site Log Book as defined in the CSWGP. When the Site Log Book or portion thereof is electronically developed, the electronic documentation must be accessible onsite. As a part of the Site Log Book, the Contractor shall develop and maintain a tracking table to show that identified TESC compliance issues are fully resolved within 10 calendar days. The table shall include the date an issue was identified, a description of how it was resolved, and the date the issue was fully resolved. The ESC Lead shall also inspect all areas disturbed by construction activities, all on-site erosion and sediment control BMP’s, and all stormwater discharge points at least once every calendar week and within 24-hours of runoff events in which stormwater discharges from the site. Inspections of temporarily stabilized inactive sites may be reduced to once every calendar month. For projects with a CSWGP, the Washington State Department of Ecology’s Erosion and Sediment Control Site Inspection Form, located at https:/ / ecology.wa.gov/Regulations-Permits/Permits-certifications/Stormwater-general-permits/ Construction-stormwater-permit shall be completed for each inspection and a copy shall be submitted to the Engineer no later than the end of the next working day following the inspection. M 41-10 Page 8-5 Erosion Control and Water Pollution Control 8-018-01.3(1)C Water Management Unless site water is to be managed in accordance with the conditions of a waste discharge permit from a local permitting authority, site water shall be managed as follows:
8-01.3(1)C1 Disposal of Dewatering Water
To manage turbid dewatering water encountered onsite, it must pass through BMPs to reduce sedimentation prior to discharging to a sediment trap or sediment pond. Turbid dewatering water disposal options may include sheet flow dispersion and infiltration within vegetation onsite, transport in a vehicle for off-site legal disposal, Ecology- approved on-site chemical treatment, sanitary or combined sewer discharge with local sewer district approval, or use of a sedimentation bag that discharges to a ditch or swale for small volumes of localized dewatering. Highly turbid or contaminated dewatering water must be handled separately from stormwater. Clean and non-turbid dewatering water may be discharged to systems tributary to or directly into surface waters of the state provided it does not cause erosion or flooding of receiving waters, in accordance with the CSWGP and water quality standards in WAC 173-201A .
8-01.3(1)C2 Process Wastewater
Wastewater generated on-site as a byproduct of a construction process shall not be discharged to surface waters of the State. Some sources of process wastewater may be infiltrated in accordance with the CSWGP. Some sources of process wastewater may be disposed via independent disposal and treatment alternatives in compliance with the applicable WACs and permits.
8-01.3(1)C3 Shaft Drilling Slurry Wastewater
Wastewater generated on-site during shaft drilling activity shall be managed and disposed of in accordance with the requirements below. No shaft drilling slurry wastewater shall be discharged to surface waters of the State. Neither the sediment nor liquid portions of the shaft drilling slurry wastewater shall be contaminated, as detectable by visible or olfactory indication (e.g., chemical sheen or smell).
1.Water-only shaft drilling slurry or water slurry with accepted flocculants may be infiltrated on-site. Flocculants used shall meet the requirements of Section 9-14.6(1) or shall be chitosan products listed as General Use Level Designation (GULD) on the Department of Ecology’s stormwater treatment technologies webpage for construction treatment. Infiltration is permitted if the following requirements are met:
a.Wastewater shall have a pH of 6.5 – 8.5 prior to discharge.
b.The amount of flocculant added to the slurry shall be kept to the minimum needed to adequately settle out solids. The flocculant shall be thoroughly mixed into the slurry.
c.The slurry removed from the shaft shall be contained in a leak proof cell or tank for a minimum of 3 hours.
d.The infiltration rate shall be reduced if needed to prevent wastewater from leaving the infiltration location. The infiltration site shall be monitored regularly during infiltration activity. All wastewater discharged to the ground shall fully infiltrate and discharges shall stop before the end of each work day.
e.Drilling spoils and settled sediments remaining in the containment cell or tank shall be disposed of in accordance with Section 6-19.3(4)F .
f.Infiltration locations shall be in upland areas at least 150 feet away from surface waters, wells, on-site sewage systems, aquifer sensitive recharge areas, sole source aquifers, well head protection areas, and shall be marked on the plan sheets before the infiltration activity begins. Page 8-6 M 41-10
8-01 Erosion Control and Water Pollution Controlg. Prior to infiltration, the Contractor shall submit a Shaft Drilling Slurry Wastewater
Management and Infiltration Plan as a Type 2 Working Drawing. This Plan shall be kept on-site, adapted if needed to meet the construction requirements, and updated to reflect what is being done in the field. The Working Drawing shall include, at a minimum, the following information:
i.Plan sheet showing the proposed infiltration location and all surface waters, wells, on-site sewage systems, aquifer-sensitive recharge areas, sole source aquifers, and well-head protection areas within 150 feet. ii. The proposed elevation of soil surface receiving the wastewater for infiltration and the anticipated phreatic surface (i.e., saturated soil). iii. The source of the water used to produce the slurry. iv. The estimated total volume of wastewater to be infiltrated.
v.The accepted flocculant to be used (if any). vi. The controls or methods used to prevent surface wastewater runoff from leaving the infiltration location. vii. The strategy for removing slurry wastewater from the shaft and containing the slurry wastewater once it has been removed from the shaft. viii. The strategy for monitoring infiltration activity and adapting methods to ensure compliance. ix. A contingency plan that can be implemented immediately if it becomes evident that the controls in place or methods being used are not adequate.
x.The strategy for cleaning up the infiltration location after the infiltration activity is done. Cleanup shall include stabilizing loose sediments on the surface within the infiltration area generated as a byproduct of suspended solids in the infiltrated wastewater or soil disturbance associated with BMP placement and removal.
2.Shaft drilling mineral slurry, synthetic slurry, or slurry with polymer additives not allowed for infiltration shall be contained and disposed of by the Contractor at an accepted disposal facility in accordance with Section 2-03.3(7)C . Spoils that have come into contact with mineral slurry shall be disposed of in accordance with Section 6-19.3(4)F .
8-01.3(1)C4 Management of Off-Site Water
Prior to clearing and grubbing, the Contractor shall intercept all sources of off-site surface water and overland flow that will run-on to the project. Off-site surface water run-on shall be diverted through or around the project in a way that does not introduce construction related pollution. It shall be diverted to its preconstruction discharge location in a manner that does not increase preconstruction flow rate and velocity and protects contiguous properties and waterways from erosion. The Contractor shall submit a Type 2 Working Drawing consisting of the method for performing this Work.
8-01.3(1)C5 Water Management for In-Water Work Below Ordinary High Water Mark
(OHWM) Work over surface waters of the state (defined in WAC 173-201A-010 ) or below the OHWM (defined in RCW 90.58.030 ) shall comply with water quality standards for surface waters of the state of Washington. M 41-10 Page 8-7 Erosion Control and Water Pollution Control 8-018-01.3(1)C6 Environmentally Acceptable Hydraulic Fluid All equipment containing hydraulic fluid that extends from a bridge deck over surface waters of the state or below the OHWM, shall be equipped with a biodegradable hydraulic fluid. The fluid shall achieve either a Pw1 Environmental Persistence Classification stated in ASTM D6046 (≥60% biodegradation in 28 days) or equivalent standard. Alternatively, hydraulic fluid that meets International Organization for Standardization (ISO 15380), the European Union Ecolabel, or equivalent certification will also be accepted. The Contractor shall submit a Type 1 Working Drawing consisting of a manufacturer catalog cut of the hydraulic fluid used. The designation of biodegradable hydraulic fluid does not mean fluid spills are acceptable. The Contractor shall respond to spills to land or water in accordance with the Contract, the associated SPCC Plan, and all applicable local, state, and federal regulations.
8-01.3(1)C7 Turbidity Curtain
All Work for the turbidity curtain shall be in accordance with the manufacturer’s recommendations for the site conditions. Removal procedures shall be developed and used to minimize silt release and disturbance of silt. The Contractor shall submit a Type 2 Working Drawing, detailing product information, installation and removal procedures, equipment and workforce needs, maintenance plans, and emergency repair/ replacement plans. Turbidity curtain materials, installation, and maintenance shall be sufficient to comply with water quality standards. The Contractor shall notify the Engineer 10 days in advance of removing the turbidity curtain. All components of the turbidity curtain shall be removed from the project.
8-01.3(1)D Dispersion/Infiltration
Water shall be conveyed only to dispersion or infiltration areas designated in the TESC Plan or to sites approved by the Engineer. Water shall be conveyed to designated dispersion areas at a rate such that, when runoff leaves the area and enters waters of the State, turbidity standards are achieved. Water shall be conveyed to designated infiltration areas at a rate that does not produce surface runoff.
8-01.3(1)E Detention/Retention Pond Construction
Permanent or temporary, ponds shall be constructed before beginning other grading and excavation Work in the area that drains into that pond. Detention/retention ponds may be constructed concurrently with grading and excavation when allowed by the Engineer. Temporary conveyances shall be installed concurrently with grading in accordance with the TESC Plan so that newly graded areas drain to the pond as they are exposed.
8-01.3(2) Temporary Seeding and Mulching
8-01.3(2)A Preparation for Application
A cleated roller, crawler tractor, or similar equipment, which forms longitudinal depressions at least 2 inches deep shall be used for compaction and preparation of the surface to be seeded. The entire area shall be uniformly covered with longitudinal depressions formed perpendicular to the natural flow of water on the slope. The soil shall be conditioned with sufficient water so the longitudinal depressions remain in the soil surface until completion of the seeding.
8-01.3(2)B Temporary Seeding
Temporary grass seed shall be a commercially prepared mix, made up of low growing grass species that will grow without irrigation at the project location, and accepted by the Engineer. The application rate shall be two pounds per 1000 square feet. Page 8-8 M 41-10
8-01 Erosion Control and Water Pollution ControlThe Contractor shall notify the Engineer not less than 24 hours in advance of seeding
operations and shall not begin the Work until areas prepared or designated for seeding have been accepted. Following the Engineer’s acceptance, seeding of the accepted slopes shall begin immediately. Temporary seeding may be sown at any time allowed by the Engineer. Temporary seeding shall be sown by one of the following methods:
1.A hydro seeder that utilizes water as the carrying agent and maintains continuous agitation through paddle blades. It shall have an operating capacity sufficient to agitate, suspend, and mix into a homogeneous slurry the specified amount of seed and water or other material. Distribution and discharge lines shall be large enough to prevent stoppage and shall be equipped with a set of hydraulic discharge spray nozzles that will provide a uniform distribution of the slurry.
2.Blower equipment with an adjustable disseminating device capable of maintaining a constant, measured rate of material discharge that will ensure an even distribution of seed at the rates specified.
3.Power-drawn drills or seeders.
4.Areas in which the above methods are impractical may be seeded by hand methods. When seeding by hand, the seed shall be incorporated into the top ¼ inch of soil by hand raking or other method that is allowed by the Engineer. Seed applied using a hydroseeder shall have a tracer added to visibly aid uniform application. This tracer shall not be harmful to plant, aquatic, or animal life. If Short-Term Mulch is used as a tracer, the application rate shall not exceed 250 pounds per acre. Seed and fertilizer may be applied in one application provided that the fertilizer is placed in the hydroseeder tank no more than 1 hour prior to application.
8-01.3(2)C Vacant
8-01.3(2)D Temporary Mulching
Temporary mulch shall be straw, wood strand, or HECP mulch and shall be used for the purpose of erosion control by protecting bare soil surface from particle displacement. Mulch shall not be applied below the anticipated water level of ditch slopes, pond bottoms, and stream banks. HECP mulch shall not be used within the Ordinary High Water Mark. Non-HECP mulches applied below the anticipated water level shall be removed or anchored down so that it cannot move or float, at no additional expense to the Contracting Agency. Straw or wood strand mulch shall be applied at a rate to achieve at least 95 percent visual blockage of the soil surface. Straw mulch shall be suitable for spreading with mulch blower equipment. Short Term Mulch shall be hydraulically applied at the rate of 2500 pounds per acre and may be applied in one lift. Short-Term Mulch shall not be used in conjunction with permanent seeding. Moderate Term Mulch and Long Term Mulch shall be hydraulically applied at the rate of 3500 pounds per acre with no more than 2000 pounds applied in a single lift. Moderate- Term Mulch shall not be used in conjunction with permanent seeding. Mulch sprayed on signs or sign Structures shall be removed the same day. Areas not accessible by mulching equipment shall be mulched by accepted hand methods.
8-01.3(2)E Tackifiers
Tackifiers applied using a hydroseeder shall have a mulch tracer added to visibly aid uniform application. This tracer shall not be harmful to plant, aquatic, or animal life. A minimum of 125 pounds per acre and a maximum of 250 pounds per acre of Short-Term M 41-10 Page 8-9 Erosion Control and Water Pollution Control 8-01Mulch shall be used as a tracer. Tackifier shall be mixed and applied in accordance with the manufacturer’s recommendations. Soil Binding Using Polyacrylamide (PAM) – The PAM shall be applied on bare soil completely dissolved and mixed in water or applied as a dry powder. Dissolved PAM shall be applied at a rate of not more than ⅔ pound per 1,000 gallons of water per acre. A minimum of 200 pounds per acre of Short-Term Mulch shall be applied with the dissolved PAM. Dry powder applications may be at a rate of 5 pounds per acre using a hand-held fertilizer spreader or a tractor-mounted spreader. PAM shall be applied only to areas that drain to completed sedimentation control BMPs in accordance with the TESC Plan. PAM may be reapplied on actively worked areas after a 48-hour period. PAM shall not be applied during rainfall or to saturated soils.
8-01.3(3) Placing Erosion Control Blanket
Erosion Control Blankets are used as an erosion prevention device and to enhance the establishment of vegetation. Erosion control blankets shall be installed according to the manufacturer’s recommendations. When used to enhance the establishment of seeded areas, seeding and fertilizing shall be done prior to blanket installation. Select erosion control blanket material for an area based on the intended function: slope or ditch stabilization, and site specific factors including soil, slope gradient, rainfall, and flow exposure. Erosion Control Blankets shall not be used on slopes or in ditches that exceed the manufacturer’s recommendations.
8-01.3(4) Placing Compost Blanket
Compost blankets are used for erosion control. Compost blanket shall only be placed on ground surfaces that are steeper than 3-foot horizontal and 1-foot vertical though steeper slopes shall be broken by wattles or compost socks placed according to the Standard Plans . Compost shall be placed to a depth of 3 inches over bare soil. An organic tackifier shall be placed over the entire composted area when dry or windy conditions are present or expected. The tackifier shall be applied immediately after the application of compost to prevent compost from leaving the composted area. Medium compost shall be used for the compost blanket. Compost may serve the purpose of soil amendment as specified in Section 8-02.3(6) .
8-01.3(5) Plastic Covering
Erosion Control – Plastic coverings used to temporarily cover stockpiled materials, slopes or bare soils shall be installed and maintained in a way that prevents water from intruding under the plastic and prevents the plastic cover from being damaged by wind. Plastic coverings shall be placed with at least a 12-inch overlap of all seams and be a minimum of 6 mils thick. Soil stabilization and energy dissipation BMPs shall be used to minimize the erosive energy flows coming off sloped areas of plastic (e.g., toe of slope). When feasible, the Contractor shall prevent clean runoff from plastic from hitting bare soil. Flows from plastic shall be directed to stabilized outlet areas. Containment – Plastic coverings used to line concrete washout areas, contain wastewaters, or used in secondary containment to prevent spills, shall be seamless to prevent infiltration and be a minimum of 10 mils thick. Vegetation Management – Plastic covering shall be clear when placed over areas that have been seeded and shall be black when placed over areas where vegetation growth is to be inhibited. Plastic covering for vegetation management shall be a minimum of 4 mils thick. Page 8-10 M 41-10
8-01 Erosion Control and Water Pollution Control8-01.3(6) Check Dams
Check dams are used as an erosion and sediment control device in channels or conveyance areas. Check dams shall be installed as soon as construction will allow, or when directed by the Engineer. The Contractor may substitute a different check dam material, in lieu of what is specified in the contract, with approval of the Engineer. Straw bales shall not be used as check dams. The check dam is a temporary or permanent structure, built across a minor channel placed perpendicular to the flow of water. Water shall not flow freely through the check dam structure. Check dams shall be constructed in a manner that creates a ponding area upstream of the dam to allow pollutants to settle, with water from increased flows channeled over a spillway in the check dam. The check dam shall be constructed to prevent erosion in the area below the spillway. The outer edges shall extend up the sides of the conveyance to prevent water from going around the check dam. Check dams shall be of sufficient height to maximize detention, without causing water to leave the ditch. Wattles, coir logs and compost sock used as check dams shall not be trenched in and shall be installed as shown in the Standard Plans . When wattles, coir logs, and compost socks are used as check dams they shall be measured and paid as check dam in accordance with Section 8-01.4 and 8-01.5 .
8-01.3(6)A Coir Log
Coir logs are used as erosion and sediment control or bank stabilizing device. Coir logs shall be laid out, spaced, staked, and installed in accordance with the Standard Plans . Live stakes can be used in addition to, but not as a replacement for, wooden stakes.
8-01.3(7) Stabilized Construction Entrance
Temporary stabilized construction entrance shall be constructed in accordance with the Standard Plans , prior to construction vehicles entering the roadway from locations that generate sediment track out on the roadway. Material used for stabilized construction entrance shall be free of extraneous materials that may cause or contribute to track out. When the stabilized entrance no longer prevents track out of sediment or debris, the Contractor shall either rehabilitate the existing entrance to original condition, or construct a new entrance. When the Contract requires a tire wash in conjunction with the stabilized entrance, the Contractor shall include details for the tire wash and the method for containing and treating the sediment-laden runoff as part of the TESC Plan. All vehicles leaving the site shall stop and wash sediment from their tires.
8-01.3(8) Street Cleaning
Self-propelled pickup street sweepers shall be used to remove and collect sediment and other debris from the Roadway. The street sweeper shall effectively collect these materials and prevent them from being washed or blown off the Roadway or into waters of the State. Street sweepers shall not generate fugitive dust and shall be designed and operated in compliance with applicable air quality standards. Material collected by the street sweeper shall be disposed of in accordance with Section 2-03.3(7)C . When allowed by the Engineer, power broom sweepers may be used in non-sensitive areas. The broom sweeper shall sweep dirt and other debris from the roadway into the work area. The swept material shall be prevented from entering or washing into waters of the State. Street washing with water will require the concurrence of the Engineer. M 41-10 Page 8-11 Erosion Control and Water Pollution Control 8-018-01.3(9) Sediment Control Barriers Sediment control barriers shall be installed in accordance with TESC Plan or manufacturer’s recommendations in the areas of clearing, grubbing, earthwork or drainage prior to starting those activities. The sediment control barriers shall be maintained until the soils are stabilized.
8-01.3(9)A Fencing
8-01.3(9)A1 High Visibility Fencing
High visibility fencing (HVF) shall be orange in color and installed along the site preservation lines shown in the Plans or as specified by the Engineer. Post spacing and attachment of the fencing material to the posts shall be as shown in the Standard Plans . The HVF shall not be fastened to trees.
8-01.3(9)A2 Silt Fence
Silt fence shall be black in color and used as a sediment control device to prevent sediment laden water from leaving project boundaries, to manage stormwater within the site, or to create small detention areas. Silt fence shall be installed at locations shown in the Plans. The geotextile shall be securely attached to the posts and support system. Post spacing and attachments shall be as shown in the Standard Plans . Geotextile material shall be sewn together at the point of manufacture, or at a location approved by the Engineer, to form geotextile lengths as required. All sewn seams and overlaps shall be located at a support post. Posts shall be either wood or steel. Wood posts shall have minimum dimensions of 1¼ by 1¼ inches by the minimum length shown in the Plans. When sediment deposits reach approximately ⅓ the height of the silt fence, the deposits shall be removed and stabilized in accordance with Section 8-01.3(15) . If trenching is not feasible due to rocky soils or not advisable due to proximity to a downslope sensitive area, a different sediment control device that does not require trenching shall be used in place of silt fence. Backup support is needed for silt fence in areas where extra strength may be required, such as the toe of steep cut or fill slopes or areas where equipment may push excessive soils toward the fence. When backup support is used, wire shall have a maximum mesh spacing of 2 inches, and the plastic mesh shall be as resistant to ultraviolet radiation as the geotextile it supports. The strength of the wire or plastic mesh shall be equivalent to or greater than as required in Section 9-33.2(1) , Table 6, for unsupported geotextile (i.e., 180 lbs. grab tensile strength in the machine direction). Post spacing and attachments shall be as shown in the Standard Plans .
8-01.3(9)A3 High Visibility Silt Fence
High visibility silt fence (HVSF) shall be orange in color and only be used for the dual purpose of demarcating site preservation lines and a sediment control device in a location where high visibility mesh fence and black silt fence would otherwise be used together at same location. If use of HVSF is allowed the geotextile material shall meet the material requirements of Section 9-33.2(1) , Table 6. Post spacing and attachments shall be as shown in the Standard Plans . Backup support is needed for high visibility silt fence (HVSF) in areas where extra strength may be required, such as the toe of steep cut or fill slopes or areas where equipment may push excessive soils toward the sensitive or protected areas. When backup support is used, wire shall have a maximum mesh spacing of 2 inches, and the plastic mesh shall be as resistant to ultraviolet radiation as the geotextile it supports. The strength of the wire or plastic mesh shall be equivalent to or greater than as required in Section 9-33.2(1) , Page 8-12 M 41-10
8-01 Erosion Control and Water Pollution ControlTable 6, for unsupported geotextile (i.e., 180 lbs. grab tensile strength in the machine
direction). Post spacing shall be as shown in the Standard Plans . When sediment deposits reach approximately ⅓ the height of the silt fence, or 8 inches whichever is lower the deposits shall be removed and stabilized in accordance with
8-01.3(9)B Gravel Filter, Wood Chip, or Compost Berm
Filter berms shall retain sediment and direct flows. The gravel filter berm shall be a minimum of 1 foot in height and shall be maintained at this height for the entire time they are in use. Rock material used for filter berms shall meet the grading requirements in Section 9-03.9(2) , but shall not include recycled materials as outlined in Section 9-03.21 . The wood chip berm shall be a minimum of 2 feet in height and shall be maintained at this height for the entire time they are in use. The Compost Berm shall be constructed in accordance with the detail in the Plans. Compost shall be Medium Compost.
8-01.3(9)C Vacant
8-01.3(9)D Inlet Protection
Inlet protection shall be installed below or above, or as a prefabricated cover at each inlet grate, as shown in the Plans. Inlet protection devices shall be installed prior to beginning clearing, grubbing, or earthwork activities. Geotextile fabric in all prefabricated inlet protection devices shall meet or exceed the requirements of Section 9-33.2 , Table 1, for Moderate Survivability, and the minimum filtration properties of Table 2. When the depth of accumulated sediment and debris reaches approximately ½ the height of an internal device or ⅓ the height of the external device (or less when so specified by the manufacturers), or as designated by the Engineer, the deposits shall be removed and stabilized on-site in accordance with Section 8-01.3(16) . Below Inlet Grate Below Inlet Grate devices shall be prefabricated units specifically designed for inlet protection and shall remain securely attached to the drainage Structure when fully loaded with sediment and debris, or at the maximum level of sediment and debris specified by the manufacturer. Above Inlet Grate Above Inlet Grate devices may be silt fence, sandbags, or prefabricated units specifically designed for inlet protection. The device shall remain securely in place around the drainage Structure under all conditions. Inlet Grate Cover Inlet Grate Cover devices shall be prefabricated units specifically designed for inlet protection and have the following features:
1.Be a sewn geotextile fabric unit fitted to the individual grate and completely enclosing the grate.
2.Have built-in lifting devices to allow manual access of the stormwater system.
3.Utilize an orange monofilament geotextile fabric. Check dams or functionally equivalent devices may be used as inlet protection devices with the approval of the Engineer. M 41-10 Page 8-13 Erosion Control and Water Pollution Control 8-018-01.3(10) Wattles Wattles are used as a flow control and sediment control device. Wattles shall be installed as soon as construction will allow or when designated by the Engineer. Wattle installation and trenching shall begin from the base of the slope and work uphill prior to topsoil or compost placement. Excavated material from trenching shall be spread evenly along the uphill slope and be compacted using hand tamping or other method approved by the Engineer. On gradually sloped or clay-type soils trenches shall be 2 to 3 inches deep. On loose soils, in high rainfall areas, or on steep slopes, trenches shall be 3 to 5 inches deep, or half the thickness of the wattle, whichever is greater. Wattles shall be laid out, spaced, and staked in accordance with the Standard Plans . Live stakes can be used in addition to, but not as a replacement for, wooden stakes. If trenching and staking is not possible due to rocky soils, compost socks shall be used instead of wattles. The Contractor shall exercise care when installing wattles to ensure the method of installation minimizes the disturbance of waterways and prevents sediment or pollutant discharge into water bodies.
8-01.3(11) Outlet Protection
Outlet protection shall prevent scour at the outlets of ponds, pipes, ditches or other conveyances. All quarry spall material used for outlet protection shall be free of extraneous material and meet the gradation requirements in Section 9-13.1(5) .
8-01.3(12) Compost Sock
Compost socks are used to disperse flow and sediment. Compost socks shall be installed as soon as construction will allow but before flow conditions create erosive flows or discharges from the site. Compost socks shall be installed prior to mulching or compost placement. Compost socks shall be laced together end-to-end with coir rope or ends shall be securely overlapped to create a continuous length. Terminal ends of the continuous length shall be curved 2 to 4 feet upward into the slope to prevent concentrated flows from going around the terminal ends. Finished grades shall be of a natural appearance with smooth transitions. Compost for compost socks shall be Medium Compost. Compost socks shall be laid out, spaced and staked in accordance with the Standard Plans . Live stakes can be used in addition to, but not as a replacement for, wooden stakes. If staking is not possible or if the compost sock is being used on concrete, heavy blocks or an equivalent item shall be used to weigh down and secure the sock. The Contractor shall exercise care when installing compost socks to ensure that the method of installation minimizes disturbance of waterways and prevents sediment or pollutant discharge into water bodies. Stakes shall be removed to minimize soil disturbance.
8-01.3(13) Temporary Curb
Temporary curbs shall divert or redirect water around erodible soils. Temporary curbs shall be installed along pavement edges to prevent runoff from flowing onto erodible slopes. Water shall be directed to areas where erosion can be controlled. Temporary curbs shall be a minimum of 4 inches in height. Temporary curb shall be installed so that ponding does not occur in the adjacent roadway.
8-01.3(14) Temporary Pipe Slope Drain
Temporary pipe slope drain shall be Corrugated Polyethylene Drain Pipe and shall be constructed in accordance with the Plans. Water interceptor dikes or temporary curbs shall be used to direct water into pipe slope drain. The entrance to the drain may consist of a prefabricated funnel device specifically designed for application, rock, sand bags, or as approved by the Engineer. Page 8-14 M 41-10
8-01 Erosion Control and Water Pollution ControlThe pipe fittings shall be water tight and the pipe secured to the slope with metal posts,
wood stakes, or sand bags. The water shall be discharged to a stabilized conveyance, sediment trap, stormwater pond, rock splash pad, or vegetated strip, in a manner to prevent erosion and maintain water quality compliance.
8-01.3(15) Maintenance
Erosion and sediment control BMPs shall be maintained or adaptively managed as required by the CSWGP until the Engineer determines they are no longer needed. When deficiencies in functional performance are identified, the deficiencies shall be rectified immediately. The BMPs shall be inspected on the schedule outlined in Section 8-01.3(1)B for damage and sediment deposits. Damage to or undercutting of BMPs shall be repaired immediately. In areas where the Contractor’s activities have compromised the erosion control functions of the existing grasses, the Contractor shall overseed at no additional cost to the Contracting Agency. The quarry spalls of construction entrances shall be refreshed, replaced, or screened to maintain voids between the spalls for collecting mud and dirt. Unless otherwise specified, when the depth of accumulated sediment and debris reaches approximately ⅓ the height of the BMP the deposits shall be removed. Debris or contaminated sediment shall be disposed of in accordance with Section 2-03.3(7)C . Clean sediments may be stabilized on-site using BMPs as allowed by the Engineer.
8-01.3(16) Removal
The Contractor shall remove all temporary BMPs, all associated hardware and associated accumulated sediment deposition from the project limits prior to Physical Completion unless otherwise allowed by the Engineer. When the temporary BMP materials are made of natural plant fibers unaltered by synthetic materials the Engineer may allow leaving the BMP in place. The Contractor shall remove BMPs and associated hardware in a way that minimizes soil disturbance. The Contractor shall permanently stabilize all bare and disturbed soil after removal of BMPs. If the installation and use of the erosion control BMPs have compacted or otherwise rendered the soil inhospitable to plant growth, such as construction entrances, the Contractor shall take measures to rehabilitate the soil to facilitate plant growth. This may include, but is not limited to, ripping the soil, incorporating soil amendments, or seeding with the specified seed. At the request of the Contractor and at the sole discretion of the Engineer the CSWGP may be transferred back to the Contracting Agency. Approval of the Transfer of Coverage request will require the following:
1.All other Work required for Contract Completion has been completed.
2.All Work required for compliance with the CSWGP has been completed to the maximum extent possible. This includes removal of BMPs that are no longer needed and the site has undergone all Stabilization identified for meeting the requirements of Final Stabilization in the CSWGP.
3.An Equitable Adjustment change order for the cost of Work that has not been completed by the Contractor.
4.Submittal of the Washington State Department of Ecology Transfer of Coverage form (Ecology Form ECY 020-87a) to the Engineer. If the Engineer approves the transfer of coverage back to the Contracting Agency the requirement in Section 1-07.5(3) for the Contractor’s submittal of the Notice of Termination form to Ecology will not apply. M 41-10 Page 8-15 Erosion Control and Water Pollution Control 8-018-01.4 Measurement
8-01.4(1) Lump Sum Bid for Project (No Unit Items)
When the Bid Proposal contains the item “Erosion Control and Water Pollution Prevention” there will be no measurement of unit or force account items for Work defined in Section 8-01 except as described in Sections 8-01.4(3) and 8-01.4(4) . Also, except as described in Section 8-01.4(3) , all of Sections 8-01.4(2) and 8-01.5(2) are deleted.
8-01.4(2) Item Bids
When the Proposal does not contain the items “Erosion Control and Water Pollution Prevention”, Sections 8-01.4(1) and 8-01.5(1) are deleted and the Bid Proposal will contain some or all of the following items measured as noted. ESC lead will be measured per day for each day that an inspection is made and a report is filed. Erosion control blanket and plastic covering will be measured by the square yard along the ground slope line of surface area covered and accepted. Turbidity curtains will be measured by the linear foot along the ground line of the installed curtain. Check dams will be measured per linear foot one time only along the ground line of the completed check dam. No additional measurement will be made for check dams that are required to be rehabilitated or replaced due to wear. Stabilized construction entrances will be measured by the square yard by ground slope measurement for each entrance constructed. Tire wash facilities will be measured per each for each tire wash installed. Street cleaning will be measured by the hour for the actual time spent cleaning pavement, refilling with water, dumping and transport to and from cleaning locations within the project limits, as authorized by the Engineer. Time to mobilize the equipment to or from the project limits on which street cleaning is required will not be measured. Inlet protections will be measured per each for each initial installation at a drainage structure. Silt fence, gravel filter, compost berms, and wood chip berms will be measured by the linear foot along the ground line of the completed barrier. Wattles and compost socks will be measured by the linear foot. Temporary curbs will be measured by the linear foot along the ground line of the completed installation. Temporary pipe slope drains will be measured by the linear foot along the flow line of the pipe. Coir logs will be measured by the linear foot along the ground line of the completed installation. Outlet protections will be measured per each initial installation at an outlet location. Temporary seeding, temporary mulching, and tackifiers will be measured by the acre by ground slope measurement. Compost blanket will be measured by the square yard by ground slope surface area covered and accepted. Page 8-16 M 41-10
8-01 Erosion Control and Water Pollution Control8-01.4(3) Reinstating Unit Items with Lump Sum Erosion Control and
Water Pollution Prevention The Contract Provisions may establish the project as lump sum, in accordance with Section 8-01.4(1) and also include one or more of the items included above in Section
8-01.4(2) When that occurs, the corresponding measurement provision in Section
8-01.4(2) is not deleted and the Work under that item will be measured as specified.
8-01.4(4) Items not included with Lump Sum Erosion Control and Water
Pollution Prevention Compost blanket will be measured by the square yard by ground slope surface area covered and accepted. Temporary mulch will be measured by the acre by ground slope surface area covered and accepted. High visibility fence will be measured by the linear foot along the ground line of the completed fence.
8-01.5 Payment
8-01.5(1) Lump Sum Bid for Project (No Unit Items)
Payment will be made for the following Bid item when it is included in the Proposal: “Erosion Control and Water Pollution Prevention”, lump sum. The lump sum Contract price for “Erosion Control and Water Pollution Prevention” shall be full pay to perform the Work as described in Section 8-01 except for costs compensated by Bid Proposal items inserted through Contract Provisions as described in Section 8-01.4(2) . Progress payments for the lump sum item “Erosion Control and Water Pollution Prevention” will be made as follows:
1.The Contracting Agency will pay 15 percent of the bid amount for the initial set up for the item. Initial set up includes the following:
a.Acceptance of the TESC Plan provided by the Contracting Agency or submittal of a new TESC Plan,
b.Submittal of a schedule for the installation of the BMPs,
c.Identifying water quality sampling locations, and
2.Seventy percent of the bid amount will be paid in accordance with Section 1-09.9 .
3.Once the project is physically complete and copies of the all reports submitted to Ecology have been submitted to the Engineer, and, if applicable, transference of the CSWGP back to the Contracting Agency is complete, the remaining 15 percent of the bid amount shall be paid in accordance with Section 1-09.9 . M 41-10 Page 8-17 Erosion Control and Water Pollution Control 8-018-01.5(2) Item Bids “ESC Lead”, per day. “Turbidity Curtain”, per linear foot. “Erosion Control Blanket”, per square yard. “Plastic Covering”, per square yard. “Check Dam”, per linear foot. “Inlet Protection”, per each. “Gravel Filter Berm”, per linear foot. “Stabilized Construction Entrance”, per square yard.” “Tire Wash”, per each. “Street Cleaning”, per hour. “Silt Fence”, per linear foot. “Wood Chip Berm”, per linear foot. “Compost Berm”, per linear foot. “Wattle”, per linear foot. “Compost Sock”, per linear foot. “Coir Log”, per linear foot. “Temporary Curb”, per linear foot. “Temporary Pipe Slope Drain”, per linear foot. “Temporary Seeding”, per acre. “Temporary Mulching”, per acre. “Compost Blanket”, per square yard. “Outlet Protection”, per each. “Tackifier”, per acre. “Erosion/Water Pollution Control”, by force account as provided in Section 1-09.6 . Maintenance and removal of erosion and water pollution control devices including removal and disposal of sediment, stabilization and rehabilitation of soil disturbed by these activities, and all additional Work deemed necessary by the Engineer to control erosion and water pollution will be paid by force account in accordance with Section 1-09.6 . To provide a common Proposal for all Bidders, the Contracting Agency has entered an amount in the Proposal to become a part of the Contractor’s total Bid.
8-01.5(3) Reinstating Unit Items with Lump Sum Erosion Control and
Water Pollution Prevention The Contract may establish the project as lump sum, in accordance with Section 8-01.4(1) and also reinstate the measurement of one or more of the items described in Section
8-01.4(2) , except for Erosion/Water Pollution Control, by force account. When that
occurs, the corresponding payment provision in Section 8-01.5(2) is not deleted and the Work under that item will be paid as specified.
8-01.5(4) Items not included with Lump Sum Erosion Control and
Water Pollution Prevention Payment will be made for the following Bid item when it is included in the Proposal: “High Visibility Fence”, per linear foot. The unit contract price per linear foot for “High Visibility Fence” shall be full pay for all costs to obtain, install, maintain, and remove the fence as specified. Once removed, the fencing shall remain the property of the Contractor.
Source: Washington Standard Specifications for Road, Bridge, and Municipal Construction, 2024 Edition. Pages 751–767 of 1,151.