Construction Stormwater Pollution Prevention Notes

Last updated October 11, 2024
By Emma Howland

The intent of the CSWPP is to prevent the transport of sediment and other impacts, like increased runoff, related to land disturbing activities. Erosion of disturbed areas on construction sites can result in excessive sediment transport to adjacent properties and to surface waters. This sediment can result in major adverse impacts, such as flooding from obstructed drainage ways, smothering of salmonid spawning beds, algal blooms in lakes, and exceedances of state water quality standards of turbidity.

Terms:

Turbidity: The measure of relative clarity of water by the amount of light that is scattered by material in the water when a light is shined through a sample. Materials that cause increased turbidity include clay, silt, very tiny inorganic and organic matter, algae, dissolved colored organic compounds, and microscopic organisms. Turbidity is measured with Nephelometric Turbidity Units (NTUs).

Example of Turbidity Levels

Wet Season: October 1st – April 30th. Any site with exposed soils shall be subject to the Wet Season Requirements- In addition to the ESC cover measures, these provisions include covering any newly-seeded areas with mulch and seeding as much disturbed area as possible during the first week of October to provide grass cover for the wet season. A separate “Wet Season” ESC plan shall be submitted and approved before continuing work on any site during the wet season.

CSWPP Measures: CSWPP measures include Erosion and Sediment Control (ESC) measures and Stormwater Pollution Prevention and Spill measures (SWPPS)

ESC measures:

  • Clearing Limits
  • Cover Measures
  • Perimeter Protection
  • Traffic Area Stabilization
  • Sediment Retention
  • Surface Water Collection
  • Dewatering Control
  • Dust Control
  • Flow Control
  • Control Pollutants
  • Protect Existing and Proposed Flow Control BMPs
  • Maintain BMPs
  • Manage the Project

SWPPS Measures:

  • Follow effective pollutant handling and disposal procedures
  • Provide cover and containment for materials, fuel, and other pollutants
  • Manage the project site to maximize pollutant control and minimize pollutant sources.
  • Protect from spills and drips of petroleum products and other pollutants
  • Avoid overapplication or untimely application of checmicals and fertilizers
  • Prevent or treat contamination of Stormwater runoff by PH modifying sources

CSWPP Performance and Compliance Provisions: In some cases, strict adherence to specified measures may not be necessary or practicable based on site conditions or project type. In other cases, immediate action may be needed to avoid sever impacts.

Monitoring of Discharges: the CSWPP supervisor shall havea turbidity meter onsite and shall use it to monitor surface and storm water discharges from the project site and into onsite wetlands, streams, or lakes whenever runoff occurs from onsite activities and during storm events.

ESC Performance: This performance is intended to be achieved through proper selection, installation, and operation of measures to prevent (to the maximum extent practicable) the transport of sediment from the project site to downstream drainage systems or surface waters or into onsite wetlands, streams, or lakes, or onto adjacent properties.

  • IF a turbidity test of surface and storm water discharges leaving the project site is greater than the benchmark value (25 NTU) but less than 250 NTU, the CSWPP supervisor shall do the following:
    • Review the ESC plan for compliance and make appropriate revisions within 7 days of the discharge that exceeded the benchmark of 25 NTU
    • Fully implement and maintain appropriate ESC measures as soon as possible but no later than 10 days after the discharge that exceeded the benchmark and
    • Document ESC implementation and maintenance in the site log book
  • IF a turbidity test of surface or storm water entering onsite wetlands, streams, or lakes indicates a turbidity level greater than 5 NTU above background when the background turbidity is 50 NTU or less, or 10% above background when the background turbidity is greater than 50 NTU or less, or 10% above background when the background turbidity is greater than 50 NTU, then corrective actions and/or additional measures beyond those specified.
  • IF discharge turbidity is 250 NTU or greater, the CSWPP Supervisor shall do all of the following:
    • Notify the County by telephone
    • Review the ESC plan for compliance and make appropriate revisions within 7 days of the discharge that exceeded the benchmark of 25 NTU
    • Fully implement and maintain appropriate ESC measures as soon as possible but no later than 10 days after the discharge that exceeded the benchmark
    • Document ESC implementation and maintenance in the site log book
    • Continue to sample discharges until turbidity is 25 NTU or lower, or the turbidity is no more than 10% over background turbidity.
  • IF the County determines that the condition of the construction site poses a hazard to adjacent property or may adversely impact drainage facilities or water resources, then additional measures may be required.

TECHNICAL INFORMATION REPORT (TIR)

The full TIR is a comprehensive supplemental report containing all technical information and analysis necessary to develop the site improvement plan. This report shall contain all calculations, conceptual design analysis, reports, and studies required and used to construct a complete site improvement plan based on sound engineering practices and careful geotechnical and hydrological design. There are a total of 10 sections:

  1. Project Overview
  2. Conditions and Requirements Summary
  3. Offsite Analysis
  4. Flow Control, Low Impact Development (LID) and Water Quality Facility Analysis and Design
  5. Conveyance System Analysis and Design
  6. Special Reports and Studies
  7. Other Permits
  8. CSWPP Analysis and Design
  9. Bond Quantities, Facility summaries, and Declaration of Covenant
  10. Operations and Maintenance Manual

TIR SECTION 8:

ESC Plan Analysis and Design (Part A)

  1. The Site Improvement Plan shall be used as the base of the ESC plan (detailed information that is not relevant such as pipe/catch basin size, stub-out locations, etc. may be omitted to make it more legible) and shall include the following information:
    • Existing and proposed roads, driveways and parking areas
    • buildings
    • drainage facilities and BMPs
    • utility corridors not associated with roadways
    • relevant critical areas, and critical area buffers
    • proposed final topography

The ESC plan shall generally be designed for proposed topography to address site disturbances for all phases of construction (clearing, grading, installation of utilities, surfacing, and final stabilization. If construction is being phased, separate ESC plans may need to be prepared to address the specific needs for each phase of construction.

2.3.1.3. Erosion and Sediment Control

The ESC plan shall be consistent with the information provided in Section 8 of the TIR and shall address the following:

  1. Identify areas with a high susceptibility to erosion
  2. Provide all details necessary to clearly illustrate the intent of the ESC design
  3. Include ESC measures for all on- and offsite utility construction included in the project
  4. Specify the construction sequence. The construction sequence shall be specifically written for the proposed project.
  5. Include ESC standard plan notes
  6. Include an inspection and maintenance program for ESC measures, including designation of a CSWPP supervisor who is a certified ESC professional and identification of phone numbers for 24-hour contact
  7. Include the basis of calculations of selection and sizing of ESC measures.

Measure-Specific Information:

Clearing Limits

Delineate clearing limits, provide details sufficient to install and maintain clearing limits in order to prevent disturbances of the project site that are not designated for clearing or grading. Clearing limits shall be installed at the edges of all critical area buffers and any other areas required to be left uncleared. In general, natural vegetation and native topsoil shall be retained in an undisturbed state to the maximum extent possible.

Types of Clearing Limit BMPs:

Mark perimeter with a continuous length of brightly-colored survey tape

Cover Measures

Any exposed soils that will remain unworked for more than the time limit set above shall be covered by the end of the working day. If the exposed area is to remain unworked for more than 30 days, the area shall be seeded with the temporary seed mix or an equivalent mix that will provide rapid protection.

Specify the type and location of temporary cover measures to be used onsite. If more than one type of cover measure is to be used onsite, indicate the areas where the different measures will be used, including steep cut and fill slopes. If the type of cover measures to be used will vary depending on time of year, soil type, gradient, or some other factor, specify that the conditions that control the use of the different measures. Specify the nature and location of permanent cover measures (unless a landscaping plan is prepared, then this may be unnecessary). Specify the approximate amount of cover measures necessary to cover all disturbed areas. If netting, blankets, or plastic sheeting are specified, provide typical detail sufficient for installation and maintenance. Specify the mulch types, seed mixes, fertilizers, and soil amendments to be used, as well as the application rate for each item. For surface roughening, describe methods, equipment and areas where surface roughening will be used. If PAM is used, show locations and describe application method. When compost blankets are used, show location, application rates, and the name of the supplier to document that compost meets quality specifications.

Types of Cover Measure BMPs:

  • D.2.1.2.1. Surface Roughening
  • D.2.1.2.2. Mulching
  • D.2.1.2.3. Erosion control nets and blankets (to be used in conjunction with seeding steep slopes)
  • D.2.1.2.4. Plastic covering
  • D.2.1.2.5. Straw WattlesD.2.1.2.6. Temporary and Permanent SeedingD.2.1.2.7. SoddingD.2.1.2.8 Polyacrylamide (PAM) for Soil Erosion
  • D.2.1.2.9. Compost Blankets

Perimeter Protection

Specify location and type of perimeter protection to be used. Provide typical details sufficient to install and maintain the perimeter protection. If silt fence is to be used, specify the type of fabric to be used. If compost berms or socks are used, documentation must be provided to assure the supplier meets the criteria and compost meets quality standards.

Traffic Area Stabilization

Locate the Construction entrance(s). Provide typical details sufficient to install and maintain the construction entrance. Locate the construction roads and parking areas. Specify the measure(s) that will be used to create stabilized construction roads and parking areas. Provide sufficient detail to install and maintain. If a wheel wash or tire bath system will be installed, provide location, typical details for installation and maintenance. Provide a list of dust control products that will be used onsite and the location of potential application areas.

Sediment Retention

Show the locations of all sediment ponds and traps. Dimension pond berm widths and all inside and outside pond slopes. Indicate the trap/pond storage required and the depth, length, and width dimensions. Provide typical section views through pond and outlet structures. If chemical or electrocoagulation treatment of sediment-laden waters will be used, approval documentation from Ecology must be included. Provide details for disposal of contaminated or chemically treated waters. Include appropriate approval docs from local sewer districts if contaminated or chemically treated water will be discharged to the sanitary sewer. Provide typical details of the control structure and dewatering mechanism. Detail stabilization techniques for outlet/inlet protection. Provide details sufficient to install cell dividers. Specify mulch or recommended cover of berms and slopes. Indicate the required depth gage with a prominant mark at 1 foot depth for sediment removal. Indicate catch basins that are to be protected. Indicate existing and proposed flow control BMP areas that are to be protected. Provide details of the catch basin and flow control BMP protection sufficient to install and maintain.

Surface Water Control

Locate all pipes, ditches, interceptor ditches, dikes, and swales that will be used to convey stormwater. Provide details sufficient to install and maintain all conveyances. Indicate locations of outlets of any possible dewatering systems. Provide details of alternative discharge methods from dewatering systems if adequate infiltration rates cannot be achieved. Do not route dewatering water, clean or untreated, through stormwater sediment ponds. Indicate the location of any level spreaders and provide details sufficient to install and maintain. Show all temporary pipe inverts. Provide location and specifications for the interception of runoff from disturbed areas and the conveyance of the runoff to a non-erosive discharge point. Provide locations of rock check dams. Provide details, including front and side sections, of typical rock check dams.

Protection of Existing and Proposed Flow Control BMP Areas

Provide perimeter protection at existing and proposed flow control BMP locations. Provide cautionary plan notes emphasizing avoidance of negative impacts to receptor soils and existing vegetation to remain.

BMP Maintenance

Provide adequate plan notes for guidance of BMP maintenance methods and schedules. Include an inspection and maintenance program for ESC measures.

Management of the Project

Provide plan notes to clarify and emphasize the management responsibilities for the project. Include an inspection and maintenance program for ESC measures, including designation of a CSWPP supervisor who is a certified ESC professional and identification of phone numbers for 24-hour contact.

Wet Season Requirements

Provide a list of all applicable wet season requirements. Clearly identify that from October 1st through April 30th, no soils shall be exposed for more than two consecutive working days. Also note that this two-day requirement may be applied at other times of the year if storm events warrant more conservative measures. Clearly identify that exposed soils shall be stabilized at the end of the workday prior to a weekend, holiday, or predicted rain event.

Critical Areas Restrictions

Delineate and label the following critical areas and any applicable buffers that are on or adjacent to the project site:

  • aquatic areas
  • wetlands
  • flood hazard areas
  • erosion hazard areas
  • landslide hazard areas
  • steep slope hazard areas
  • critical aquifer recharge areas

If construction creates disturbed areas within any of the above listed critical areas or associated buffers, specify the type locations and details of any measures or other provisions necessary to comply with the critical area restrictions in Appendix D and protect surface waters and steep slopes.

2.3.1.4 Stormwater Pollution Prevention and Spill Plan

The SWPPS plan must be kept on site during all phases of construction and shall address the construction-related pollution-generating activities. The plan must include a description of the methods the general contractor will use to ensure sub-contractors are aware of the SWPPS plan. A form or record must be provided that states all sub-contractors have read and agree to the SWPPS plan.

The SWPPS plan consists of 3 elements:

  1. A site plan showing the location and description of BMPs required to prevent pollution and control spills from construction activities and from chemicals and other materials used and stored on the construction site.
  2. A pollution prevention report listing the potential sources of pollution and identifying the operational, source control and treatment BMPs necessary to prevent/mitigate pollution from these sources.
  3. A spill prevention and cleanup report describing the procedures and BMPs for spill prevention and including provisions for cleanup of spills should they occur.

Activity-specific informatioSin required:

Storage and Handling of Liquids

all liquids that will be handled or stored onsite including but not limited to petroleum products, fuel, solvents, detergents, paint, pesticides, concrete admixtures, and form oils. Specify types and sizes of containers of liquids that will be stored/handled onsite. Show locations on the SWPPS site plan. Describe secondary containment methods adequately sized to provide containment for all liquids stored onsite.

Storage and Stockpiling of Construction Materials and Wastes

Identify construction materials and wasts that may be generated or stockpiled onsite. Show the locations where these materials and wasts will be generated and stockpiled on the SWPPS site plan. Specify type of cover measures to be used to keep rainwater from contacting construction materials and wastes that can contribute pollutants to storm, surface, or ground water. If wastes are kept in containers, describe how rainwater will be kept out of the containers.

Fueling

Specify method of onsite fueling for construction equipment (i.e. stationary tanks, truck mounted tanks, wet hosing, etc.) If stationary tanks will be used show their location on the site plan. Describe type and size of tanks. Describe containment methods for fuel spills. If fueling occurs during evening hours, describe lighting and signage plan.

Maintenance, Repairs and Storage of Vehicles and Equipment

Identify maintenance and repair areas and show their locations on the SWPPS site plan. Use of trip pans or plastic beneath vehicles is required and must be noted on the site plan. Describe method for collection, storage, and disposal of vehicle fluids. If an area is designated for vehical maintenance, signs must be posted that state no vehicle washing may occur in the area and it must be noted on the site plan.

Concrete Saw Cutting, Slurry, and Washwater Disposal

Assure that washout of concrete trucks is performed off-site or in designated concrete washout areas only. Identify truck washout areas to assure such areas are not within a critical aquifer recharge area. If they are, the washout area must be lined with an impervious membrane. Show location information on the site plan. Locate washout area at least 50 feet from sensitive areas such as storm drains, open ditches, or water bodies, including wetlands.

Specify size of sumps needed to collect and contain slurry and washwater. show location information on the site plan. Identify areas for rinsing hand tools including but not limited to screeds, shovels, rakes, floats, and trowels. Show the locations on the site plan. Describe methods for collecting, treating, and disposal of waste water from exposed aggregate processes, concrete grinding and saw cutting, and new concrete washing and curing water.

Handling of pH Elevated Water

New concrete vaults/structures may cause collected water to have an elevated pH. This water cannot be discharged to storm or surface water until neutralized. Provide details on treating/neutralizing water when pH is not within neutral parameters. Written approval from Ecology is required before using chemical treatment other than CO2 or dry ice. Provide details on disposal of water with elevated pH or of the treated water.

Application of Chemicals including Pesticides and Fertilizers

Provide a list of chemicals that may be used on the project site and the application rates. Describe where and how chemicals will be applied and stored on the site plan.

SWPPS Site Plan

Identify locations of:

  1. Where liquids will be stored as well as secondary containment areas
  2. Where construction materials and wastes will be generated and stockpiled
  3. Fueling for vehicles and equipment if stationary tanks will be used
  4. Containment areas for fuel spills
  5. Lighting and signage for fueling during evening hours
  6. Maintenance and repair areas and clearly note drip pans or plastic shall be used beneath vehicles. also note that signs must be posted that state no vehicle washing may occur in the area.
  7. Where truck washout areas are and identify the location of slurry/washwater sumps and rinsing areas for tools.
  8. Where chemicals will be applied and identify where they will be stored
  9. Where spill response materials will be stored.

Pollution Prevention Report

  1. List the possible sources of pollution and identify the BMPs to be used for each source to prevent pollution. Include any supporting information for the selection and sizing of pollution prevention BMPs.
  2. Identify the personnel responsible for pollution prevention and clearly list the responsibilities of each person identified. Contact information for these personnel must be clearly identified in the report and on the SWPPS site plan.
  3. Describe the procedures to be used for monitoring pollution prevention BMPs and for responding to a BMP that needs attention including keeping records/reports of all inspections of pollution prevent BMPs.

Spill Prevention and Cleanup Report

This report provides the specifics on spill prevention and cleanup and must include the following information in addition to any activity-specific information

  1. list all possible sources of a spill and identify the BMPs to be used for each source to prevent a spill.
  2. Identify personnel responsible for spill prevention and cleanup and list responsibilities of each person identified. Contact information for these personnel must be clearly identified in the report and on the SWPPS site plan.
  3. Describe the procedures to be used for monitoring spill prevention BMPs and for responding to a spill incident
  4. Identify where spill response materials will be stored. Make reference to the SWPPS site plan for location information
  5. Identify disposal methods for contaminated water and soil after a spill.

D.2.1.2 Cover Measures

Temporary and permanent cover measures will be used to protect disturbed areas that are to remain unworked for more than 7 days during the dry season and 12 hours during the wet season.

Proposed BMPs:

  • Exposed areas to remain unworked for more than 30 days shall be seeded with temporary seed mix
  • D.2.1.2.5. Straw Wattles

Inspection and Maintenance Plan: Inspect wattles prior to forecasted rain, daily during extended rain events, after rain events, weekly during the wet season and at two week intervals at all other times of the year. Repair or replace split, torn raveling, or slumping wattles. Remove sediment accumulations when exceeding ½ the height between the top of the wattle and the ground surface.

D.2.1.3 Perimeter Protection

In order to reduce the amount of sediment transported beyond the disturbed areas of the construction site, perimeter protection is to be installed prior to any upslope clearing and grading.

List and Describe BMPs:

  • D.2.1.3.1. Silt Fence
    • D.2.1.3.2. Brush Barrier
    • D.2.1.3.3. Vegetated Strip
    • D.2.1.3.4. Triangular Silt Dike
    • D.2.1.3.5 Compost Berms
    • D.2.1.3.6 Compost Socks

Inspection and Maintenance Plan: Install Silt fence downslope of all disturbed areas and inspectweekly. Any damage shall be repaired immediately. If concentrated flows are evident uphill of the fence, they must be intercepted and conveyed to a sediment trap or pond. It is important to check the uphill side of the fence for signs of the fence clogging or acting as a barrier flow and then causing channelization of flows parallel to the fence. If this occurs, replace the fence or remove the trapped sediment.

D.2.1.4 Traffic Area Stabilization

In order to reduce the amount of sediment transported off site by construction vehicles and to reduce the erosion of areas disturbed by vehicle traffic, the construction entrance is to be installed as the first step in clearing and grading. Construction road stabilization shall occur immediately after initial grading of the construction roads and parking areas and will be installed in the location of the proposed access entrance on SW 129TH street.

List and describe BMPs:

  • D.2.1.4.1 Stabilized Construction Entrance
  • D.2.1.4.2 Construction Road/Parking Area Stabilization
  • D.2.1.4.3 Wheel Wash

Inspection and Maintenance Plan: Weekly Inspection. Quarry Spalls (or hog fuel) shall be added if the pad is no longer in accordance with the specifications. If entrance is not preventing sediment from being tracked onto pavement, then alternative measures to keep the streets free of sediment shall be used. This may include street sweeping, an increase in the dimensions of the entrance, or the installation of a wheel wash. If washing is used, it shall be done on an area covered with crushed rock, and wash water shall drain to a sediment trap or pond. Any sediment that is tracked onto pavement shall be removed immediately by sweeping. The sediment collected by sweeping shall be removed or stabilized on site. The pavement shall not be cleaned by washing down the street except when sweeping is ineffective and there is a threat to public safety. If it is necessary to wash the streets, a small sump must be constructed. The sediment would then be washed into the sump where it can be controlled. Any quarry spalls that are loosened from the pad and end up on the roadway shall be removed immediately. If vehicles are entering or exiting the site at points other than the construction entrance(s), fencing shall be installed to control traffic.

D.2.1.5  Sediment Retention

The purpose of sediment retention facilities is to remove sediment from runoff generated from disturbed areas. Sediment facilities shall be constructed as the first step in the clearing and grading of the site. The surface water conveyances may then be connected to the facilities as site development proceeds.

List and Describe BMPs:

  • D.2.1.5.1 Sediment Trap
    • D.2.1.5.2 Sediment Pond
  • D.2.1.5.3 Storm Drain Inlet Protection

Inspection and Maintenance Plan: This project proposes to use filter fabric protection on storm drain inlets in support of the treatment facilities.  

D.2.1.6 Surface Water Collection

The purpose of surface water collection is to collect and convey surface water so that erosion is minimized, and runoff from disturbed areas is treated by a sediment pond or trap. Surface water control essentially consists of three elements.

  • Interception of runoff on and above slopes
    • Conveyance of the runoff to a sediment pond or trap
    • Release of the runoff downslope of any disturbed areas

Surface water runoff will be conveyed by sheet flow and in our opinion the downstream silt fences will provide adequate surface water control. We do not propose any additional BMPs for this requirement

D.2.1.7  Dewatering Control

Dewatering control measures shall be used whenever there is a potential for runoff from dewatering of utilities, excavations, foundations, etc. to prevent the untreated discharge of sediment-laden water.

List and Describe BMPs:

  • Infiltration
  • Transport offsite in a vehicle, such as a vacuum flush truck, for legal disposal in a manner that does not pollute surface waters
  • Discharge to the sanitary sewer discharge with local sewer district approval if there is no other option, or
  • Use of a sedimentation bag with outfall to a ditch or swale for small volumes of localized dewatering.
  • *Clean, non-turbid dewatering water may be discharged via stable conveyance to systems tributary to surface waters. Provided the dewatering flow does not cause erosion or flooding of the receiving waters
  • *Highly turbid or contaminated dewatering water (high pH or other) shall be handled separately from stormwater.

D.2.1.8 Dust Control

To prevent wind transport of dust from exposed soil surfaces onto roadways, drainage ways, and surface waters, dust control shall be implemented when exposed soils are dry to the point that wind transport is possible and roadways, drainage ways, or surface waters are likely to be impacted.

List and Describe BMPs:

  • Water: spray soils until wet but runoff shall not be generated by spraying.

D.2.1.9 Flow Control

The purpose of surface water flow control is to mitigate increases in runoff peaks that occur during construction as a result of clearing vegetation, compacting the soil, and adding impervious surface. Such increases can cause or aggravate downstream flooding and erosion.

Surface water flow control shall be installed or otherwise provided prior to any clearing and/or grading of the site, except that required to construct the surface water flow control facilities.

List and Describe BMPs:

  • Detention facility: Temporarily stores surface water runoff and discharges at a reduced rate.
  • Retention facility: stores water longer and effectively has no surface outflow (outflow occurs by evaporation or soaking into the ground)
  • Infiltration facility: Retention facilities that rely entirely on the soaking of collected surface water into the ground
  • R/D facility: all flow control facilities

Flow Control BMPs or “low impact development BMPs” are methods and designs for dispersing, infiltrating, or otherwise reducing or preventing development-related increases in runoff at or near the sources of those increases.

D.2.1.2.5 Straw Wattles: Wattles and sediment control barriers consisting of straw wrapped in biodegradable tubular plastic or similar encasing material. Wattles may reduce the velocity and can spread the flow of rill and sheet runoff, and can capture sediment. They are usually 8-10 inches in diameter and 25-30 feet in length. The wattles are place in shallow trenches and staked along the contour of disturbed or newly constructed slopes

D.2.1.10 Protect Existing and Proposed Flow Control BMPs

The purpose of protecting existing and proposed flow control BMP areas is to avoid sedimentation and soil compaction that would adversely affect infiltration and also avoid contamination by other pollutants. Flow control BMP area protection shall be installed or otherwise provided prior to any clearing and/or grading of the site, except that required to construct flow control BMPs. The following measures will be used to ensure that all BMPs will be applied/installed and maintained through the duration of the project:

  • Installation and maintenance of erosion and sediment control BMPs on portions of the site that drain into the flow control BMPs
  • BMPs shall be restored to their fully functioning condition if they accumulate sediment during construction.
  • Prevent compacting bioretention BMPs by excluding construction equipment and foot traffic. Protect completed lawn and landscaped areas from compaction due to construction equipment
  • Do not allow muddy construction equipment on the base material or pavement.
  • Pavement fouled with sediments or no longer passing an initial filtration text must be cleaning using procedures from the local stormwater manual or manufacturer’s procedures.
  • Keep all heavy equipment off existing soils under flow control BMPs that have been excavated to final grade to retain the infiltration rate of the soils.

D.2.1.11 Maintain Protective BMPs

The purpose of maintaining protected BMPs is to provide continuous erosion and sediment control protection throughout the life of the project and avoid sedimentation, soil compaction and contamination by other pollutants that would adversely affect infiltration and surface runoff. Protection measures shall be monitored per section D.2.4.4. at a minimum and promptly maintained to fully functioning condition as necessary to assure continued performance of their intended function. The following measures will be used to meet this requirement:

  • Maintain and repair all temporary and permanent erosion and sediment control BMPs.
  • Remove all temporary erosion and sediment control BMPs prior to final construction approval
  • Provide protection to all BMPs installed for the permanent control of stormwater from sediment and compaction
  • Remove or stabilize trapped sediment on site.

D.2.1.12 Manage the Project

Coordination and timing of site development activities relative to ESC concerns and timely inspection, maintenance and update of protective measures are necessary to effectively manage the project and assure success of protective ESC and SWPPS design and implementation. The following measures will be used to meet this requirement:

  • Phase development project to the maximum extent possible and take into account seasonal work limits.
  • Inspection and Monitoring
  • Maintaining an updated Construction SWPPP
  • Project sites less than one acre may have a person without CESCL certification conduct inspections. By the initiation of construction, the SWPPP must identify the inspector, who shall be present on-site or on-call at all times.