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HomeMy WebLinkAboutRS_SWPPP_251107_V1Construction Stormwater General Permit (CSWGP) Stormwater Pollution Prevention Plan (SWPPP) for Vision House Phase IV Prepared for: The Washington State Department of Ecology Northwest Regional Office 3190 160th Ave SE Bellevue, WA 98008 Permittee / Owner Developer Operator / Contractor Derek Sciba Vision House P.O. Box 2951 Renton, WA 98056 Derek Sciba Vision House P.O. Box 2951 Renton, WA 98056 TBD Certified Erosion and Sediment Control Lead (CESCL) Name Organization Contact Phone Number TBD TBD TBD SWPPP Prepared By Name Organization Contact Phone Number Samuel Salo Encompass Engineering & Surveying (425) 392-0250 SWPPP Preparation Date 11/06/2025 Project Construction Dates Activity / Phase Start Date End Date Site Grading To Be Determined To Be Determined Construction of Improvements and Utilities To Be Determined To Be Determined TABLE OF CONTENTS PROJECT INFORMATION (1.0) ....................................................................................................... 5 CONSTRUCTION STORMWATER BEST MANAGEMENT PRACTICES (BMPS) (2.0) ........................... 8 POLLUTION PREVENTION TEAM (3.0) ......................................................................................... 23 MONITORING AND SAMPLING REQUIREMENTS (4.0) ................................................................. 24 DISCHARGES TO 303(D) OR TOTAL MAXIMUM DAILY LOAD (TMDL) WATERBODIES (5.0) .......... 27 REPORTING AND RECORD KEEPING (6.0) .................................................................................... 28 LIST OF TABLES 1. Summary of Site Pollutant Constituents 2. Pollutants 3. pH-Modifying Sources 4. Management 5. Team Information 6. Turbidity Sampling Method 7. pH Sampling Method List of Appendices A. Civil Site Plans B. BMP Detail C. Site Inspection Form D. CSWGP E. Engineering Calculations List of Acronyms and Abbreviations Acronym / Abbreviation Explanation 303(d) Section of the Clean Water Act pertaining to Impaired Waterbodies BFO Bellingham Field Office of the Department of Ecology BMP(s) Best Management Practice(s) CESCL Certified Erosion and Sediment Control Lead CO2 Carbon Dioxide CRO Central Regional Office of the Department of Ecology CSWGP Construction Stormwater General Permit CWA Clean Water Act DMR Discharge Monitoring Report DO Dissolved Oxygen Ecology Washington State Department of Ecology EPA United States Environmental Protection Agency ERO Eastern Regional Office of the Department of Ecology ERTS Environmental Report Tracking System ESC Erosion and Sediment Control GULD General Use Level Designation NPDES National Pollutant Discharge Elimination System NTU Nephelometric Turbidity Units NWRO Northwest Regional Office of the Department of Ecology pH Power of Hydrogen RCW Revised Code of Washington SPCC Spill Prevention, Control, and Countermeasure su Standard Units SWMMEW Stormwater Management Manual for Eastern Washington SWMMWW Stormwater Management Manual for Western Washington SWPPP Stormwater Pollution Prevention Plan TESC Temporary Erosion and Sediment Control SWRO Southwest Regional Office of the Department of Ecology TMDL Total Maximum Daily Load VFO Vancouver Field Office of the Department of Ecology WAC Washington Administrative Code WSDOT Washington Department of Transportation WWHM Western Washington Hydrology Model Project Information (1.0) Project/Site Name: Vision House Phase IV Street/Location: 511 Airport Way City: Renton State: WA Zip code: 98059 Subdivision: N/A Receiving waterbody: Lower Cedar River Existing Conditions (1.1) Total acreage: 53,578 (1.23 AC) Disturbed acreage: 52,504 (1.20 AC) Existing structures: The site is currently developed with gravel parking, miscellaneous concrete, a small structure, and a play area. Landscape topography: The site grades down to the east at slopes of 2-8%. A moderate-steep slope of 10-30% is localized in the southeast corner of the site. Drainage patterns: Stormwater runoff produced from the existing site sheet flows over moderate slopes ranging from 2-35% towards the natural discharge area (NDA) which is generally located along the eastern portion of the site. The property is located within the Lower Cedar River drainage basin, within the Cedar River/Lake Washington watershed. Existing Vegetation: Grass lawn with scattered large trees. Critical Areas: A 75-foot buffer is required for the wetland, and a 50-foot buffer is required for the stream. List of known impairments for 303(d) listed or Total Maximum Daily Load (TMDL) for the receiving waterbody: PH, Temperature, and Disolved Oxygen Table 1 includes a list of suspected and/or known contaminants associated with the construction activity. Table 1 – Summary of Site Pollutant Constituents Constituent (Pollutant) Location Depth Concentration Gasoline/Diesel/Oil/Hydraulic Fluid Construction Vehicles Proposed Construction Activities (1.2) Description of site development: This project proposes the demolition of all existing structures/appurtenances on-site (apart from the existing play area located in the northern portion of the site), and the construction of a new commercial structure. The proposed on-site impervious surfaces will include an 18,814 SF building (roof area), 13,839 SF of asphalt driveway & parking areas, and 2,722 SF of concrete walkways/steps/ramps. The proposed off-site impervious surfaces include 1,574 SF of asphalt aprons & parking areas and 546 SF of concrete walkways/ramps. The total proposed impervious surface area associated with the project is 37,495 SF, of which 35,375 SF is located on-site Description of construction activities: The project site will be cleared and graded prior to the start of construction. The development of the site will include site grading and utilities installation. Utilities will include stormwater, sanitary sewer, potable water, and all private utilities. Description of site drainage including flow from and onto adjacent properties: A Level 1 Downstream Analysis from the engineering Technical Information Report has been included in this section. Level I Downstream Analysis Stormwater runoff in the existing conditions leaves the site from one natural discharge area located along the eastern side of the property. Runoff begins by sheet flowing over flat to moderate slopes ranging from 2-35% until passing through the eastern property limits. Once exiting the site, runoff continues to follow the natural topography eastward until reaching the Highland Professional Plaza parking lot. Stormwater would then enter the stormwater system located in the western portion of the Highland Professional Plaza which contains a detention pond in the southwestern portion of the property. Per Renton’s GIS Mapping System, this detention pond discharges runoff to the south where it then would converge with an unnamed stream/ditch that flows in the western direction. After travelling west within this stream for approximately 300 feet, runoff is conveyed into the public stormwater system which travels westward beneath Bremerton Avenue NE. The storm system continues travelling to the west, passing through ‘The Windsor’ apartment complex. After another 350 feet, the storm system continues travelling west until reaching a Safeway parking lot within TPN 880500-0030. The system continues conveying runoff in the western/southwestern direction until reaching a bioswale facility located south of an AutoZone. The storm system does not appear to discharge runoff into the bioswale; per Renton’s GIS Mapping System, it appears the bioswale system outlets runoff into the stormwater system in which the subject downstream flowpath is located. From here, the system would convey runoff to the southern side of NE 4th Street. This is where the ¼ mile downstream limit was reached. No drainage related issues were observed downstream of the site, and no relevant drainage complaints were identified on the King County iMap system within a quarter mile of the site discharge location. Description of final stabilization: Final stabilization of the site will include revegetation and landscaping of exposed areas, as well as paving of driveways, sidewalks and parking areas. Contaminated Site Information: Proposed activities regarding contaminated soils or groundwater: There are no known contaminated soils on site. No contamination is anticipated with the proposed construction. Construction Stormwater Best Management Practices (BMPs) (2.0) The SWPPP is a living document reflecting current conditions and changes throughout the life of the project. These changes may be informal (i.e. hand-written notes and deletions). Update the SWPPP when the CESCL has noted a deficiency in BMPs or deviation from original design. The 12 Elements (2.1) Element 1: Preserve Vegetation / Mark Clearing Limits (2.1.1) The limits of clearing and grading will be marked in several ways around the site depending on the location. Combination high visibility orange/silt fencing will be installed along clearing limits. During the clearing effort, the topsoil and duff materials should be kept in a separate stockpile for future use to help promote grass growth during project close out. List and describe BMPs: BMP C103: High Visibility Fence BMP C233: Silt Fence Installation Schedules: Marking the clearing limits is one of the first things to be accomplished on the construction site. Prior to any site clearing or grading, areas that are to remain undisturbed during project construction shall be delineated. Once construction is complete, the clearing limit BMP’s may be removed as approved by the City. Inspection and Maintenance plan: The clearing limits should be observed on a daily basis and thoroughly inspected weekly to ensure they are in place and function to protect areas that are not being cleared. If tree roots have been exposed or injured, “prune” cleanly with an appropriate pruning saw or loppers directly above the damaged roots and cover with native soils. As the majority of the site is relatively flat, no excess clogging of the silt fence is not anticipated, however BMPs should be checked consistently for effectiveness. Any damaged or missing portions of the clearing limit BMPs should be repaired or replaced immediately. Responsible Staff: CESCL Element 2: Establish Construction Access (2.1.2) A stabilized construction entrance is proposed on the southern side of this site for access off of the existing vision house property. This site has no frontage to Bremerton AVE NE, however, the existing vision house access should be cleaned regularly to avoid soils from being tracked out into public ROW. If construction vehicles are observed to be tracking soil onto the roads, the construction entrance will be maintained via the replacement/cleaning of the quarry spalls. If refreshment of the construction access proves ineffective, a wheel wash can be installed at the construction access. List and describe BMPs: BMP C105: Stabilized Construction Entrance BMP C107: Construction Road/Parking Area Stabilization Installation Schedules: The stabilized construction entrance should be established at the start of construction for all active access points. The construction road/parking area stabilization should be established after preliminary grading is completed. Inspection and Maintenance plan: The construction entrance will be observed daily for any deficiencies such as dirt or mud covering the rocks. Also, the public roads will be observed on a continual basis during vehicle exiting to ensure no soil deposits are being tracked onto the roadway. If the construction entrance proves inadequate to prevent soil from being deposited onto the roadway, additional measures will be necessary, including street sweeping and the use of a wheel wash for pervasive failures. Other stabilized areas will be inspected regularly, especially after large storm events. Any damaged or missing portions of the site BMPs should be repaired or replaced immediately. Responsible Staff: CESCL Element 3: Control Flow Rates (2.1.3) At all times, flow rates shall be controlled for this project. Natural drainage patterns shall be protected as much as possible during construction, and concentrated flow should not be permitted. Properties and waterways downstream from development sites shall be protected from erosion due to increases in the volume, velocity, and peak flow rate of stormwater runoff from the project site. Will you construct stormwater retention and/or detention facilities? Yes No Will you use permanent infiltration ponds or other low impact development (example: rain gardens, bio- retention, porous pavement) to control flow during construction? Yes No List and describe BMPs: BMP C233: Silt Fence Installation Schedules: Construction of the BMPs and associated infrastructure is scheduled for the beginning of the project. The measures described above are required throughout construction. Inspection and Maintenance plan: The BMPs should be inspected on a weekly basis to verify that the capacity has not diminished due to sedimentation in such a way that the BMP loses efficiency. Any damaged or missing portions of the site BMPs should be repaired or replaced immediately. Responsible Staff: CESCL Element 4: Install Sediment Controls (2.1.4) In order to minimize the discharge of pollutants, this project will utilize the listed sediment control BMPs. Silt fencing will be used to reduce sediment discharge from the site. List and describe BMPs: BMP C233: Silt Fence Installation Schedules: Implementation of sediment control BMPs is scheduled for the beginning of the project. These BMPs will be functional before other land disturbing activities take place. The measures described above are required throughout construction. Inspection and Maintenance plan: The sediment control facilities should be inspected on a weekly basis to verify that the capacity has not diminished due to sedimentation in such a way that the BMP loses efficiency. The uphill side of the fencing should be checked regularly for signs of clogging. Sediment deposits should be removed when the deposit reaches approximately one-third the height of the silt fence. Any damaged or missing portions of the site BMPs should be repaired or replaced immediately. Responsible Staff: CESCL Element 5: Stabilize Soils (2.1.5) Soils on site will be stabilized as appropriate through a variety of methods. These BMPs will be implemented when soil is to remain unworked or at the threat of rain throughout the project. Areas to be paved will be stabilized by the early application of a gravel base. Stockpiles will be covered with plastic sheeting unless an extended period of storage is expected, in which case the stockpiles should be seeded and covered with mulch and an erosion control net. Runoff from plastic sheeting will be directed to an acceptable discharge location. During the hot summer months, dust control is necessary. This is accomplished by applying water to dry soils routinely. Water should not be applied in a way that creates runoff. West of the Cascade Mountains Crest Season Dates Number of Days Soils Can be Left Exposed During the Dry Season May 1 – September 30 7 days During the Wet Season October 1 – April 30 2 days Soils must be stabilized at the end of the shift before a holiday or weekend if needed based on the weather forecast. Anticipated project dates: Start date: Spring 2026 End date: Spring 2027 Will you construct during the wet season? Yes No List and describe BMPs: BMP C120: Temporary and Permanent Seeding BMP C121: Mulching BMP C123: Plastic Covering BMP C140: Dust Control Installation Schedules: Soil Stabilization BMPs will be applied as deemed necessary. Exposed areas should be evaluated and covered to prevent impacts to roadways, drainage ways, or surface waters. Seeding shall be used throughout the project on disturbed areas that have reached final grade or that will remain unworked for more than 30 days. Inspection and Maintenance plan: Soil Stabilization BMPs should be reviewed daily and thoroughly inspected weekly and after each rainfall event to ensure they are functioning appropriately. All deficiencies shall be repaired or replaced in accordance with the number of days exposed soils may be left exposed. Any damaged or missing portions of the site BMPs should be repaired or replaced immediately. Responsible Staff: CESCL Element 6: Protect Slopes (2.1.6) Any slopes on-site created by grading and excavation will be stabilized upon completion of grading with a combination of hydroseed and mulch. Seeding will be utilized in disturbed areas that have reached final grade of that will remain unworked for more than 30 days. Will steep slopes be present at the site during construction? Yes No List and describe BMPs: BMP C120: Temporary and Permanent Seeding BMP C121: Mulching Installation Schedules: Slopes are to be protected throughout construction. Inspection and Maintenance plan: Stabilized slopes created during construction should be inspected on a weekly basis and after every rainfall event. Repairs to stabilization BMPs should be made in accordance to the exposed soils schedule. Areas that fail to establish at least 80 percent cover will be reseeded as necessary. Any damaged or missing portions of the site BMPs should be repaired or replaced immediately. Responsible Staff: CESCL Element 7: Protect Drain Inlets (2.1.7) Catch basin inserts will be installed on all onsite and downstream catch basins on the adjacent Vision House Property . List and describe BMPs: BMP C220: Storm Drain Inlet Installation Schedules: Storm drain inlets are to be installed prior to the start of construction for all existing inlets. Constructed onsite catch basins will be protected prior to the first gravel lift. Inspection and Maintenance plan: All facilities should be inspected weekly and after every rainfall event. BMPs showing 1/3 of their capacity full of sediment should have the sediment removed or the unit replaced. Any damaged or missing portions of the site BMPs should be repaired or replaced immediately. Responsible Staff: CESCL Element 8: Stabilize Channels and Outlets (2.1.8) No channels or outfalls are proposed at this time. List and describe BMPs: None are proposed at this time Installation Schedules: None proposed at this time Inspection and Maintenance plan: None proposed at this time Responsible Staff: CESCL Element 9: Control Pollutants (2.1.9) The following pollutants are anticipated to be present on-site: Table 2 – Pollutants Pollutant (and source, if applicable) Gasoline in vehicles Concrete poured in place There are no known pollutants contained on the existing site. During construction, the contractor will need to conduct maintenance, fueling, and repair of heavy equipment and vehicles off-site, as spills of hazardous materials could result in an environmental event. If a wheel wash is incorporated into the protection plan, the contractor will discharge wheel wash wastewater to a separate on-site treatment system that prevents discharge to surface water, such as closed-loop recirculation or upland land application, or to the sanitary sewer, with local sewer district approval. Concrete will be handled in ways to eliminate concrete, concrete process water, and concrete slurry from entering waters of the state. List and describe BMPs: BMP C151: Concrete Handling BMP C152: Sawcutting and Surfacing Pollution Prevention BMP C153: Material Delivery, Storage and Containment BMP C154: Concrete Washout Area Installation Schedules: BMPs will be implemented at the beginning of construction and as needed throughout the project. Concrete washout BMPs shall be in place prior to the commencement of concrete work. Inspection and Maintenance plan: Inspection of the concrete washout area should be done weekly and prior to expected concrete pours. Washout facilities must be cleaned, or new facilities must be constructed and ready for use one the washout is 75% full. Secondary containment facilities should be inspected daily and repaired or replaced as necessary. Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. Any damaged or missing portions of the site BMPs should be repaired or replaced immediately. Responsible Staff: CESCL Will maintenance, fueling, and/or repair of heavy equipment and vehicles occur on-site? Yes No List and describe BMPs: BMP C153: Material Delivery, Storage and Containment Installation Schedules: Containment of hazardous materials will be conducted throughout the duration of construction. Inspection and Maintenance plan: Containment facilities should be inspected daily and repaired or replaced as necessary. Material storage areas shall be kept clean, organized and equipped with an ample supply of appropriate spill clean-up material. Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. Any damaged or missing portions of the site BMPs should be repaired or replaced immediately. Responsible Staff: CESCL Will wheel wash or tire bath system BMPs be used during construction? Yes: If necessary No List and describe BMPs: None Installation Schedules: N/A Inspection and Maintenance plan: N/A Responsible Staff: CESCL Will pH-modifying sources be present on-site? Yes If yes, check the source(s). Table 3 – pH-Modifying Sources None X Bulk cement Cement kiln dust Fly ash Other cementitious materials X New concrete washing or curing waters X Waste streams generated from concrete grinding and sawing Exposed aggregate processes Dewatering concrete vaults X Concrete pumping and mixer washout waters Recycled concrete Other (i.e. calcium lignosulfate) [please describe] During this construction activity, the pH levels of stormwater runoff must be monitored. If pH levels exceed 8.5, the level will need to be corrected. The use of CO2 per WDOE standards will rapidly neutralize the water and make it suitable for discharge. List and describe BMPs: BMP C252 High pH Neutralization using CO2 Installation Schedules: pH neutralization using CO2 will be implemented as necessary to correct pH levels in excess of 8.5. Inspection and Maintenance plan: Operators will keep written records related to treatment as detailed in the Stormwater Management Manual for Western Washington. A copy of this record should be given to the client/contractor who should retain the record for three years. Responsible Staff: CESCL Excess concrete must not be dumped on-site, except in designated concrete washout areas with appropriate BMPs installed. Element 10: Control Dewatering (2.1.10) No dewatering is proposed at this time. List and describe BMPs: None proposed at this time. Installation Schedules: Dewatering BMPs will be established prior to the commencement of dewatering activities. Inspection and Maintenance plan: None proposed at this time. Responsible Staff: CESCL Element 11: Maintain BMPs (2.1.11) All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained and repaired as needed to ensure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP specification (see Volume II of the SWMMWW or Chapter 7 of the SWMMEW). Visual monitoring of all BMPs installed at the site will be conducted at least once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to once every calendar month. All temporary ESC BMPs will be removed within 30 days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be stabilized on-site or removed. Disturbed soil resulting from removal of either BMPs or vegetation shall be permanently stabilized. Additionally, protection must be provided for all BMPs installed for the permanent control of stormwater from sediment and compaction. BMPs that are to remain in place following completion of construction will be examined and restored to full operating condition. If sediment enters these BMPs during construction, the sediment shall be removed and the facility will be returned to conditions specified in the construction documents. Element 12: Manage the Project (2.1.12) The project will be managed based on the following principles: · Projects will be phased to the maximum extent practicable and seasonal work limitations will be taken into account. · Inspection and monitoring: o Inspection, maintenance and repair of all BMPs will occur as needed to ensure performance of their intended function. o Site inspections and monitoring will be conducted in accordance with Special Condition S4 of the CSWGP. Sampling locations are indicated on the Site Map. Sampling station(s) are located in accordance with applicable requirements of the CSWGP. · Maintain an updated SWPPP. o The SWPPP will be updated, maintained, and implemented in accordance with Special Conditions S3, S4, and S9 of the CSWGP. As site work progresses the SWPPP will be modified routinely to reflect changing site conditions. The SWPPP will be reviewed monthly to ensure the content is current. Table 4 – Management X Design the project to fit the existing topography, soils, and drainage patterns X Emphasize erosion control rather than sediment control X Minimize the extent and duration of the area exposed X Keep runoff velocities low X Retain sediment on-site X Thoroughly monitor site and maintain all ESC measures X Schedule major earthwork during the dry season Other (please describe) Element 13: Protect Low Impact Development (LID) BMPs (2.1.13) The proposed project will not incorporate LID BMPs. No protection is required for this BMP. Pollution Prevention Team (3.0) Table 5 – Team Information Title Name(s) Phone Number Certified Erosion and Sediment Control Lead (CESCL) TBD TBD Resident Engineer Samuel Salo (425) 392-0250 Emergency Ecology Contact TBD TBD Emergency Permittee/ Owner Contact Derek Sciba (425)288-6356 Non-Emergency Owner Contact Derek Sciba (425)288-6356 Monitoring Personnel TBD TBD Ecology Regional Office Northwest (425) 649-7000 Monitoring and Sampling Requirements (4.0) Monitoring includes visual inspection, sampling for water quality parameters of concern, and documentation of the inspection and sampling findings in a site log book. A site log book will be maintained for all on-site construction activities and will include: · A record of the implementation of the SWPPP and other permit requirements · Site inspections · Stormwater sampling data The site log book must be maintained on-site within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. Numeric effluent limits may be required for certain discharges to 303(d) listed waterbodies. See CSWGP Special Condition S8 and Section 5 of this template. Complete the following paragraph for sites that discharge to impaired waterbodies for fine sediment, turbidity, phosphorus, or pH: The receiving waterbody, Cedar River, is impaired for: Dissolved Oxygen, pH, and Temperature. All stormwater and dewatering discharges from the site are subject to an effluent limit of 8.5 su for pH and/or 25 NTU for turbidity. Site Inspection (4.1) Site inspections will be conducted at least once every calendar week and within 24 hours following any discharge from the site. For sites that are temporarily stabilized and inactive, the required frequency is reduced to once per calendar month. The discharge point(s) are indicated on the Site Map (see Appendix A) and in accordance with the applicable requirements of the CSWGP. Stormwater Quality Sampling (4.2) Turbidity Sampling (4.2.1) Requirements include calibrated turbidity meter or transparency tube to sample site discharges for compliance with the CSWGP. Sampling will be conducted at all discharge points at least once per calendar week. Method for sampling turbidity: Table 6 – Turbidity Sampling Method Turbidity Meter/Turbidimeter (required for disturbances 5 acres or greater in size) X Transparency Tube (option for disturbances less than 1 acre and up to 5 acres in size) The benchmark for turbidity value is 25 nephelometric turbidity units (NTU) and a transparency less than 33 centimeters. If the discharge’s turbidity is 26 to 249 NTU or the transparency is less than 33 cm but equal to or greater than 6 cm, the following steps will be conducted: 1. Review the SWPPP for compliance with Special Condition S9. Make appropriate revisions within 7 days of the date the discharge exceeded the benchmark. 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. 3. Document BMP implementation and maintenance in the site log book. If the turbidity exceeds 250 NTU or the transparency is 6 cm or less at any time, the following steps will be conducted: 1. Telephone or submit an electronic report to the applicable Ecology Region’s Environmental Report Tracking System (ERTS) within 24 hours. https://www.ecology.wa.gov/About-us/Get- involved/Report-an-environmental-issue · Northwest Region (King, Kitsap, Island, San Juan, Skagit, Snohomish, Whatcom): (425) 649-7000 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period 3. Document BMP implementation and maintenance in the site log book. 4. Continue to sample discharges daily until one of the following is true: · Turbidity is 25 NTU (or lower). · Transparency is 33 cm (or greater). · Compliance with the water quality limit for turbidity is achieved. o 1 - 5 NTU over background turbidity, if background is less than 50 NTU o 1% - 10% over background turbidity, if background is 50 NTU or greater · The discharge stops or is eliminated. pH Sampling (4.2.2) For engineered soils and recycled concrete, pH sampling begins when engineered soils or recycled concrete are first exposed to precipitation and continues until the area is fully stabilized. If the measured pH is 8.5 or greater, the following measures will be taken: 1. Prevent high pH water from entering storm sewer systems or surface water. 2. Adjust or neutralize the high pH water to the range of 6.5 to 8.5 su using appropriate technology such as carbon dioxide (CO2) sparging (liquid or dry ice). 3. Written approval will be obtained from Ecology prior to the use of chemical treatment other than CO2 sparging or dry ice. Method for sampling pH: Table 7 – pH Sampling Method pH meter X pH test kit Wide range pH indicator paper Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies (5.0) 303(d) Listed Waterbodies (5.1) Is the receiving water 303(d) (Category 5) listed for turbidity, fine sediment, phosphorus, or pH? Yes No List the impairment(s): pH The receiving waterbody, Cedar River, is impaired for: pH TMDL Waterbodies (5.2) Waste Load Allocation for CWSGP discharges: No known waste load allocation for CWSGP discharges. Reporting and Record Keeping (6.0) Record Keeping (6.1) Site Log Book (6.1.1) A site log book will be maintained for all on-site construction activities and will include: · A record of the implementation of the SWPPP and other permit requirements · Site inspections · Sample logs Records Retention (6.1.2) Records will be retained during the life of the project and for a minimum of three (3) years following the termination of permit coverage in accordance with Special Condition S5.C of the CSWGP. Permit documentation to be retained on-site: · SWPPP · Site Log Book Permit documentation will be provided within 14 days of receipt of a written request from Ecology. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with Special Condition S5.G.2.b of the CSWGP. Updating the SWPPP (6.1.3) The SWPPP will be modified if: · Found ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. · There is a change in design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the State. The SWPPP will be modified within seven (7) days if inspection(s) or investigation(s) determine additional or modified BMPs are necessary for compliance. An updated timeline for BMP implementation will be prepared. Reporting (6.2) Discharge Monitoring Reports (6.2.1) Cumulative soil disturbance is less than one (1) acre; therefore, Discharge Monitoring Reports (DMRs) will not be submitted to Ecology because water quality sampling is not being conducted at the site. Notification of Noncompliance (6.2.2) If any of the terms and conditions of the permit is not met, and the resulting noncompliance may cause a threat to human health or the environment, the following actions will be taken: 1. Ecology will be notified within 24-hours of the failure to comply by calling the applicable Regional office ERTS phone number (Regional office numbers listed below). 2. Immediate action will be taken to prevent the discharge/pollution or otherwise stop or correct the noncompliance. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. Anytime turbidity sampling indicates turbidity is 250 NTUs or greater, or water transparency is 6 cm or less, the Ecology Regional office will be notified by phone within 24 hours of analysis as required by Special Condition S5.A of the CSWGP. · Northwest Region at (425) 649-7000 for Island, King, Kitsap, San Juan, Skagit, Snohomish, or Whatcom County Include the following information: 1. Your name and / Phone number 2. Permit number 3. City / County of project 4. Sample results 5. Date / Time of call 6. Date / Time of sample 7. Project name In accordance with Special Condition S4.D.5.b of the CSWGP, the Ecology Regional office will be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH water. Appendix/Glossary A. Civil Site Plans BREMERTON AVE. NE IN COMPLIANCE WITH CITY OF RENTON STANDARDS Know what's Call below. before you dig. R Encompass Eastern Washington Division 407 Swiftwater Blvd. ▪ Cle Elum, WA 98922 ▪ Phone: (509) 674-7433 Western Washington Division 165 NE Juniper Street, Suite 201 ▪ Issaquah, WA 98027 ▪ Phone: (425) 392-0250 ENGINEERING & SURVEYING XX X X X X X X BR E M E R T O N A V E N E 5 BR E M E R T O N A V E N E DEMOLITION & TESC PLAN VISION HOUSE VISION HOUSE PHASE IV BREMERTON AVE NE NORTH EROSION & SEDIMENT CONTROL (ESC) STANDARD PLAN NOTES: CONSTRUCTION SEQUENCE: EARTHWORK QUANTITIES: CONSTRUCTION SCHEDULE: · · · DISTURBANCE AREA TABLE: DEMO NOTE: TESC LEGEND: SURVEY LEGEND: B. BMP Detail 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Figure II-3.1: Stabilized Construction Access 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Approved as Functionally Equivalent Ecology has approved products as able to meet the requirements of this BMP. The products did not  pass through the Technology Assessment Protocol – Ecology (TAPE) process. Local jurisdictions  may choose not to accept these products, or may require additional testing prior to consideration for  local use. Products that Ecology has approved as functionally equivalent are available for review on  Ecology’s website at:  https://ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Stormwater-per- mittee-guidance-resources/Emerging-stormwater-treatment-technologies 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Figure II-3.2: Wheel Wash 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 BMP C107: Construction Road / Parking Area Stabilization Purpose Stabilizing roads, parking areas, and other on-site vehicle transportation routes immediately after  grading reduces erosion caused by construction traffic or stormwater runoff. Conditions of Use Roads and parking areas shall be stabilized wherever they are constructed, whether permanent or  temporary, for use by construction traffic. BMP C103:  High-Visibility Fence shall be installed, if necessary, to limit the access of vehicles to only  those roads and parking areas that are stabilized. Design and Installation Specifications  l On areas that will receive asphalt as part of the project, install the first lift as soon as possible.  l A 6-inch depth of 2- to 4-inch crushed rock, gravel base, or crushed surfacing base course  shall be applied immediately after grading or utility installation. A 4-inch course of asphalt  treated base (ATB) may also be used, or the road/parking area may be paved. It may also be  possible to use cement or calcium chloride for soil stabilization. If cement or cement kiln dust is  used for roadbase stabilization, pH  monitoring and BMP C252:  Treating and Disposing of  High pH Water is necessary to evaluate and minimize the effects on stormwater. If the area  will not be used for permanent roads, parking areas, or structures, a 6-inch depth of hog fuel  may also be used, but this is likely to require more maintenance. Whenever possible, con- struction roads and parking areas shall be placed on a firm, compacted subgrade.  l Temporary road gradients shall not exceed 15 percent. Roadways shall be carefully graded to  drain. Drainage ditches shall be provided on each side of the roadway in the case of a  crowned section, or on one side in the case of a super-elevated section. Drainage ditches  shall be directed to a sediment control BMP.  l Rather than relying on ditches, it may also be possible to grade the road so that runoff sheet- flows into a heavily vegetated area with a well-developed topsoil. Landscaped areas are not  adequate. If this area has at least 50 feet of vegetation that water can flow  through, then it is  generally preferable to use the vegetation to treat runoff, rather than a sediment pond or trap.  The 50 feet shall not include wetlands or their buffers. If runoff is allowed to sheetflow through  adjacent vegetated areas, it is vital to design the roadways and parking areas so that no con- centrated runoff is created.  l Storm drain inlets shall be protected to prevent sediment-laden water entering the drainage  system (see BMP C220:  Inlet Protection). Maintenance Standards Inspect stabilized areas regularly, especially after large storm events. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Crushed rock, gravel base, etc., shall be added as required to maintain a stable driving surface and  to stabilize any areas that have eroded. Following construction, these areas shall be restored to pre-construction condition or better to pre- vent future erosion. Perform street cleaning at the end of each day or more often if necessary. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 before water flow; install sod in the channel bottom — over top of hydromulch and erosion con- trol blankets.  l Confirm the installation of all required surface water control measures to prevent seed from  washing away.  l Hydroseed applications shall include a minimum of 1,500 pounds per acre of mulch with 3 per- cent tackifier. See BMP C121: Mulching for specifications.  l Areas that will have seeding only and not landscaping may need compost or meal-based  mulch included in the hydroseed in order to establish vegetation. Re-install native topsoil on  the disturbed soil surface before application. See BMP T5.13: Post-Construction Soil Quality  and Depth.  l When installing seed via hydroseeding operations, only about 1/3 of the seed actually ends up  in contact with the soil surface. This reduces the ability to establish a good stand of grass  quickly. To overcome this, consider increasing seed quantities by up to 50 percent.  l Enhance vegetation establishment by dividing the hydromulch operation into two phases:  o Phase 1- Install all seed and fertilizer with 25-30 percent mulch and tackifier onto soil in  the first lift.  o Phase 2- Install the rest of the mulch and tackifier over the first lift. Or, enhance vegetation by:  o Installing the mulch, seed, fertilizer, and tackifier in one lift.  o Spread or blow straw over the top of the hydromulch at a rate of 800-1000 pounds per  acre.  o Hold straw in place with a standard tackifier. Both of these approaches will increase cost moderately but will greatly improve and enhance  vegetative establishment. The increased cost may be offset by the reduced need for:  o Irrigation.  o Reapplication of mulch.  o Repair of failed slope surfaces. This technique works with standard hydromulch (1,500 pounds per acre minimum) and Bon- ded Fiber Matrix/ Mechanically Bonded Fiber Matrix (BFM/MBFMs) (3,000 pounds per acre  minimum).  l Seed may be installed by hand if:  o Temporary and covered by straw, mulch, or topsoil.  o Permanent in small areas (usually less than 1 acre) and covered with mulch, topsoil, or  erosion blankets.  l The seed mixes listed in Table II-3.4: Temporary and Permanent Seed Mixes include  2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 recommended mixes for both temporary and permanent seeding.  l Apply these mixes, with the exception of the wet area seed mix, at a rate of 120 pounds per  acre. This rate can be reduced if soil amendments or slow-release fertilizers are used. Apply  the wet area seed mix at a rate of 60 pounds per acre.  l Consult the local suppliers or the local conservation district for their recommendations. The  appropriate mix depends on a variety of factors, including location, exposure, soil type, slope,  and expected foot traffic. Alternative seed mixes approved by the local authority may be used,  depending on the soil type and hydrology of the area. Common Name Latin Name % Weight % Purity % Germination Temporary Erosion Control Seed Mix A standard mix for areas requiring a temporary vegetative cover. Chewings or   annual blue grass Festuca rubra var. commutata or Poa anna 40 98 90 Perennial rye  Lolium perenne 50 98 90 Redtop or colonial  bentgrass  Agrostis alba or  Agrostis tenuis 5 92 85 White dutch clover Trifolium repens 5 98 90 Landscaping Seed Mix A recommended mix for landscaping seed. Perennial rye blend Lolium perenne 70 98 90 Chewings and red  fescue blend Festuca rubra var. commutata or Fes- tuca rubra 30 98 90 Low-Growing Turf Seed Mix A turf seed mix for dry situations where there is no need for watering. This mix requires very little main- tenance. Dwarf tall fescue  (several  varieties) Festuca arundin- acea var. 45 98 90 Dwarf perennial  rye (Barclay) Lolium perenne var. barclay 30 98 90 Red fescue Festuca rubra 20 98 90 Colonial bentgrass Agrostis tenuis 5 98 90 Bioswale Seed Mix A seed mix for bioswales and other intermittently wet areas. Tall or meadow fes-Festuca arundin-75-80 98 90 Table II-3.4: Temporary and Permanent Seed Mixes 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Common Name Latin Name % Weight % Purity % Germination cue acea or   Festuca elatior Seaside/Creeping  bentgrass Agrostis palustris 10-15 92 85 Redtop bentgrass Agrostis alba or  Agrostis gigantea 5-10 90 80 Wet Area Seed Mix A low-growing, relatively non-invasive seed mix appropriate for very wet areas that are not regulated wet- lands. Consult Hydraulic Permit Authority (HPA) for seed mixes if applicable. Tall or meadow fes- cue Festuca arundin- acea or Festuca elatior 60-70 98 90 Seaside/Creeping  bentgrass Agrostis palustris 10-15 98 85 Meadow foxtail Alepocurus praten- sis 10-15 90 80 Alsike clover Trifolium hybridum 1-6 98 90 Redtop bentgrass Agrostis alba 1-6 92 85 Meadow Seed Mix A recommended meadow seed mix for infrequently maintained areas or non-maintained areas where col- onization by native plants is desirable. Likely applications include rural road and utility right-of-way. Seed- ing should take place in September or very early October in order to obtain adequate establishment prior to  the winter months. Consider the appropriateness of clover, a fairly invasive species, in the mix. Amending  the soil can reduce the need for clover. Redtop or Oregon  bentgrass Agrostis alba or  Agrostis ore- gonensis 20 92 85 Red fescue Festuca rubra 70 98 90 White dutch clover Trifolium repens 10 98 90 Table II-3.4: Temporary and Permanent Seed Mixes (continued) Roughening and Rototilling  l The seedbed should be firm and rough. Roughen all soil no matter what the slope. Track walk  slopes before seeding if engineering purposes require compaction. Backblading or smoothing  of slopes greater than 4H:1V is not allowed if they are to be seeded.  l Restoration-based landscape practices require deeper incorporation than that provided by a  simple single-pass rototilling treatment. Wherever practical, initially rip the subgrade to  improve long-term permeability, infiltration, and water inflow qualities. At a minimum,  2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 permanent areas shall use soil amendments to achieve organic matter and permeability per- formance defined in engineered soil/landscape systems. For systems that are deeper than 8  inches complete the rototilling process in multiple lifts, or prepare the engineered soil system  per specifications and place to achieve the specified depth. Fertilizers  l Conducting soil tests to determine the exact type and quantity of fertilizer is recommended.  This will prevent the over-application of fertilizer.  l Organic matter is the most appropriate form of fertilizer because it provides nutrients (includ- ing nitrogen, phosphorus, and potassium) in the least water-soluble form.  l In general, use 10-4-6 N-P-K (nitrogen-phosphorus-potassium) fertilizer at a rate of 90  pounds per acre. Always use slow-release fertilizers because they are more efficient and  have fewer environmental impacts. Do not add fertilizer to the hydromulch machine, or agit- ate, more than 20 minutes before use. Too much agitation destroys the slow-release coating.  l There are numerous products available that take the place of chemical fertilizers. These  include several with seaweed extracts that are beneficial to soil microbes and organisms. If  100 percent cottonseed meal is used as the mulch in hydroseed, chemical fertilizer may not be  necessary. Cottonseed meal provides a good source of long-term, slow-release, available  nitrogen. Bonded Fiber Matrix and Mechanically Bonded Fiber Matrix  l On steep slopes use Bonded Fiber Matrix (BFM) or Mechanically Bonded Fiber Matrix  (MBFM) products. Apply BFM/MBFM products at a minimum rate of 3,000 pounds per acre  with approximately 10 percent tackifier. Achieve a minimum of 95 percent soil coverage during  application. Numerous products are available commercially. Most products require 24-36  hours to cure before rainfall and cannot be installed on wet or saturated soils. Generally,  products come in 40-50 pound bags and include all necessary ingredients except for seed and  fertilizer.  l Install products per manufacturer's instructions.  l BFMs and MBFMs provide good alternatives to blankets in most areas requiring vegetation  establishment. Advantages over blankets include:  o BFM and MBFMs do not require surface preparation.  o Helicopters can assist in installing BFM and MBFMs in remote areas.  o On slopes steeper than 2.5H:1V, blanket installers may require ropes and harnesses  for safety.  o Installing BFM and MBFMs can save at least $1,000 per acre compared to blankets. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Maintenance Standards Reseed any seeded areas that fail to establish at least 75 percent cover (100 percent cover for areas  that receive sheet or concentrated flows). If reseeding is ineffective, use an alternate method such  as sodding, mulching, nets, or blankets.  l Reseed and protect by mulch any areas that experience erosion after achieving adequate  cover. Reseed and protect by mulch any eroded area.  l Supply seeded areas with adequate moisture, but do not water to the extent that it causes run- off. Approved as Functionally Equivalent Ecology has approved products as able to meet the requirements of this BMP. The products did not  pass through the Technology Assessment Protocol – Ecology (TAPE) process. Local jurisdictions  may choose not to accept these products, or may require additional testing prior to consideration for  local use. Products that Ecology has approved as functionally equivalent are available for review on  Ecology’s website at:  https://ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Stormwater-per- mittee-guidance-resources/Emerging-stormwater-treatment-technologies 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Mulch Mater- ial Guideline Description Straw Quality Standards Air-dried; free from undesirable seed and coarse material. Application Rates 2"-3" thick; 5 bales per 1,000 sf or 2-3 tons per acre Remarks Cost-effective protection when applied with adequate thickness. Hand- application generally requires greater thickness than blown straw. The  thickness of straw may be reduced by half when used in conjunction with  seeding. In windy areas straw must be held in place by crimping, using a  tackifier, or covering with netting. Blown straw always has to be held in  place with a tackifier as even light winds will blow it away. Straw, however,  has several deficiencies that should be considered when selecting mulch  materials. It often introduces and/or encourages the propagation of weed  species and it has no significant long-term benefits It should also not be  used within the ordinary high-water elevation of surface waters (due to flot- ation). Hydromulch Quality Standards No growth inhibiting factors. Application Rates Approx. 35-45 lbs per 1,000 sf or 1,500 - 2,000 lbs per acre Remarks Shall be applied with hydromulcher. Shall not be used without seed and  tackifier unless the application rate is at least doubled. Fibers longer than  about 3/4 - 1 inch clog hydromulch equipment. Fibers should be kept to less  than 3/4 inch. Compost Quality Standards No visible water or dust during handling. Must be produced per WAC 173- 350, Solid Waste Handling Standards, but may have up to 35% biosolids. Application Rates 2" thick min.; approx. 100 tons per acre (approx. 750 lbs per cubic yard) Remarks More effective control can be obtained by increasing thickness to 3". Excel- lent mulch for protecting final grades until landscaping because it can be dir- ectly seeded or tilled into soil as an amendment. Compost used for mulch  has a coarser size gradation than compost used for BMP C125: Topsoiling  / Composting or BMP T5.13: Post-Construction Soil Quality and Depth. It  is more stable and practical to use in wet areas and during rainy weather  conditions. Do not use near wetlands or near phosphorous impaired water  bodies. Chipped Site Veget- ation Quality Standards Gradations from fines to 6 inches in length for texture, variation, and inter- locking properties. Include a mix of various sizes so that the average size  is between 2- and 4- inches. Application Rates 2" thick min.; Table II-3.6: Mulch Standards and Guidelines 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Mulch Mater- ial Guideline Description Remarks This is a cost-effective way to dispose of debris from clearing and grub- bing, and it eliminates the problems associated with burning. Generally, it  should not be used on slopes above approx. 10% because of its tendency  to be transported by runoff. It is not recommended within 200 feet of sur- face waters. If permanent seeding or planting is expected shortly after  mulch, the decomposition of the chipped vegetation may tie up nutrients  important to grass establishment.  Note: thick application of this material over existing grass, herbaceous spe- cies, and some groundcovers could smother and kill vegetation. Wood- Based Mulch Quality Standards No visible water or dust during handling. Must be purchased from a supplier  with a Solid Waste Handling Permit or one exempt from solid waste reg- ulations. Application Rates 2" thick min.; approx. 100 tons per acre (approx. 750 lbs. per cubic yard) Remarks This material is often called "wood straw" or "hog fuel". The use of mulch  ultimately improves the organic matter in the soil. Special caution is  advised regarding the source and composition of wood-based mulches. Its  preparation typically does not provide any weed seed control, so evidence  of residual vegetation in its composition or known inclusion of weed plants  or seeds should be monitored and prevented (or minimized). Wood Strand Mulch Quality Standards A blend of loose, long, thin wood pieces derived from native conifer or  deciduous trees with high length-to-width ratio. Application Rates 2" thick min. Remarks Cost-effective protection when applied with adequate thickness. A min- imum of 95-percent of the wood strand shall have lengths between 2 and  10-inches, with a width and thickness between 1/16 and 1/2-inches. The  mulch shall not contain resin, tannin, or other compounds in quantities that  would be detrimental to plant life. Sawdust or wood shavings shall not be  used as mulch. [Specification 9-14.4(4) from the Standard Specifications for Road, Bridge, and Municipal Construction (WSDOT, 2016) Table II-3.6: Mulch Standards and Guidelines (continued) 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 BMP C123: Plastic Covering Purpose Plastic covering provides immediate, short-term erosion protection to slopes and disturbed areas. Conditions of Use Plastic covering may be used on disturbed areas that require cover measures for less than 30 days,  except as stated below.  l Plastic is particularly useful for protecting cut and fill slopes and stockpiles. However, the rel- atively rapid breakdown of most polyethylene sheeting makes it unsuitable for applications  greater than six months.  l Due to rapid runoff caused by plastic covering, do not use this method upslope of areas that  might be adversely impacted by concentrated runoff. Such areas include steep and/or  unstable slopes.  l Plastic sheeting may result in increased runoff volumes and velocities, requiring additional on- site measures to counteract the increases. Creating a trough with wattles or other material  can convey clean water away from these areas.  l To prevent undercutting, trench and backfill rolled plastic covering products.  l Although the plastic material is inexpensive to purchase, the cost of installation, maintenance,  removal, and disposal add to the total costs of this BMP.  l Whenever plastic is used to protect slopes, install water collection measures at the base of the  slope. These measures include plastic-covered berms, channels, and pipes used to convey  clean rainwater away from bare soil and disturbed areas. Do not mix clean runoff from a  plastic covered slope with dirty runoff from a project.  l Other uses for plastic include:  o Temporary ditch liner.  o Pond liner in temporary sediment pond.  o Liner for bermed temporary fuel storage area if plastic is not reactive to the type of fuel  being stored.  o Emergency slope protection during heavy rains.  o Temporary drainpipe (“elephant trunk”) used to direct water. Design and Installation Specifications  l Plastic slope cover must be installed as follows:  1. Run plastic up and down the slope, not across the slope.  2. Plastic may be installed perpendicular to a slope if the slope length is less than 10 feet. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3  3. Provide a minimum of 8-inch overlap at the seams.  4. On long or wide slopes, or slopes subject to wind, tape all seams.  5. Place plastic into a small (12-inch wide by 6-inch deep) slot trench at the top of the slope  and backfill with soil to keep water from flowing underneath.  6. Place sand filled burlap or geotextile bags every 3 to 6 feet along seams and tie them  together with twine to hold them in place.  7. Inspect plastic for rips, tears, and open seams regularly and repair immediately. This  prevents high velocity runoff from contacting bare soil, which causes extreme erosion.  8. Sandbags may be lowered into place tied to ropes. However, all sandbags must be  staked in place.  l Plastic sheeting shall have a minimum thickness of 0.06 millimeters.  l If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable protection shall  be installed at the toe of the slope in order to reduce the velocity of runoff. Maintenance Standards  l Torn sheets must be replaced and open seams repaired.  l Completely remove and replace the plastic if it begins to deteriorate due to ultraviolet radi- ation.  l Completely remove plastic when no longer needed.  l Dispose of old tires used to weight down plastic sheeting appropriately. Approved as Functionally Equivalent Ecology has approved products as able to meet the requirements of this BMP. The products did not  pass through the Technology Assessment Protocol – Ecology (TAPE) process. Local jurisdictions  may choose not to accept these products, or may require additional testing prior to consideration for  local use. Products that Ecology has approved as functionally equivalent are available for review on  Ecology’s website at:  https://ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Stormwater-per- mittee-guidance-resources/Emerging-stormwater-treatment-technologies 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 BMP C140: Dust Control Purpose Dust control prevents wind transport of dust from disturbed soil surfaces onto roadways, drainage  ways, and surface waters. Conditions of Use Use dust control in areas (including roadways) subject to surface and air movement of dust where  on-site or off-site impacts to roadways, drainage ways, or surface waters are likely. Design and Installation Specifications  l Vegetate or mulch areas that will not receive vehicle traffic. In areas where planting, mulching,  or paving is impractical, apply gravel or landscaping rock.  l Limit dust generation by clearing only those areas where immediate activity will take place,  leaving the remaining area(s) in the original condition. Maintain the original ground cover as  long as practical.  l Construct natural or artificial windbreaks or windscreens. These may be designed as enclos- ures for small dust sources.  l Sprinkle the site with water until the surface is wet. Repeat as needed. To prevent carryout of  mud onto the street, refer to BMP C105:  Stabilized Construction Access and BMP C106:  Wheel Wash.  l Irrigation water can be used for dust control. Irrigation systems should be installed as a first  step on sites where dust control is a concern.  l Spray exposed soil areas with a dust palliative, following the manufacturer’s instructions and  cautions regarding handling and application. Used oil is prohibited from use as a dust sup- pressant. Local governments may approve other dust palliatives such as calcium chloride or  PAM.  l PAM (BMP C126:  Polyacrylamide (PAM) for Soil Erosion Protection) added to water at a rate  of 0.5 pounds per 1,000 gallons of water per acre and applied from a water truck is more effect- ive than water alone. This is due to increased infiltration of water into the soil and reduced  evaporation. In addition, small soil particles are bonded together and are not as easily trans- ported by wind. Adding PAM may reduce the quantity of water needed for dust control. Note  that the application rate specified here applies to this BMP, and is not the same application  rate that is specified in BMP C126:  Polyacrylamide (PAM) for Soil Erosion Protection, but the  downstream protections still apply. Refer to BMP C126:  Polyacrylamide (PAM) for Soil Erosion Protection for conditions of use.  PAM shall not be directly applied to water or allowed to enter a water body.  l Contact your local Air Pollution Control Authority for guidance and training on other dust con- trol measures. Compliance with the local Air Pollution Control Authority constitutes  2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 compliance with this BMP.  l Use vacuum street sweepers.  l Remove mud and other dirt promptly so it does not dry and then turn into dust.  l Techniques that can be used for unpaved roads and lots include:  o Lower speed limits. High vehicle speed increases the amount of dust stirred up from  unpaved roads and lots.  o Upgrade the road surface strength by improving particle size, shape, and mineral types  that make up the surface and base materials.  o Add surface gravel to reduce the source of dust emission. Limit the amount of fine  particles (those smaller than .075 mm) to 10 to 20 percent.  o Use geotextile fabrics to increase the strength of new  roads or roads undergoing recon- struction.  o Encourage the use of alternate, paved routes, if available.  o Apply chemical dust suppressants using the admix method, blending the product with  the top few inches of surface material. Suppressants may also be applied as surface  treatments.  o Limit dust-causing work on windy days.  o Pave unpaved permanent roads and other trafficked areas. Maintenance Standards Respray area as necessary to keep dust to a minimum. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Design and Installation Specifications Implementation  l Perform washout of concrete truck drums at an approved off-site location or in designated con- crete washout areas only.  l Do not wash out concrete onto non-formed areas, or into storm drains, open ditches, streets,  or streams.  l Wash equipment difficult to move, such as concrete paving machines, in areas that do not dir- ectly drain to natural or constructed stormwater conveyance or potential infiltration areas.  l Do not allow excess concrete to be dumped on-site, except in designated concrete washout  areas as allowed above.  l Concrete washout areas may be prefabricated concrete washout containers, or self-installed  structures (above-grade or below-grade).  l Prefabricated containers are most resistant to damage and protect against spills and leaks.  Companies may offer delivery service and provide regular maintenance and disposal of solid  and liquid waste.  l If self-installed concrete washout areas are used, below-grade structures are preferred over  above-grade structures because they are less prone to spills and leaks.  l Self-installed above-grade structures should only be used if excavation is not practical.  l Concrete washout areas shall be constructed and maintained in sufficient quantity and size to  contain all liquid and concrete waste generated by washout operations. Education  l Discuss the concrete management techniques described in this BMP with the ready-mix con- crete supplier before any deliveries are made.  l Educate employees and subcontractors on the concrete waste management techniques  described in this BMP.  l Arrange for the contractor’s superintendent or Certified Erosion and Sediment Control Lead  (CESCL) to oversee and enforce concrete waste management procedures.  l A sign should be installed adjacent to each concrete washout area to inform concrete equip- ment operators to utilize the proper facilities. Contracts Incorporate requirements for concrete waste management into concrete supplier and subcontractor  agreements. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Location and Placement  l Locate concrete washout areas at least 50 feet from sensitive areas such as storm drains,  open ditches, water bodies, or wetlands.  l Allow convenient access to the concrete washout area for concrete trucks, preferably near the  area where the concrete is being poured.  l If trucks need to leave a paved area to access the concrete washout area, prevent track-out  with a pad of rock or quarry spalls (see BMP C105:  Stabilized Construction Access). These  areas should be far enough away from other construction traffic to reduce the likelihood of acci- dental damage and spills.  l The number of concrete washout areas you install should depend on the expected demand  for storage capacity.  l On large sites with extensive concrete work, concrete washout areas should be placed in mul- tiple locations for ease of use by concrete truck drivers. Concrete Truck Washout Procedures  l Washout of concrete truck drums shall be performed in designated concrete washout areas  only.  l Concrete washout from concrete pumper bins can be washed into concrete pumper trucks  and discharged into designated concrete washout areas or properly disposed of off-site. Concrete Washout Area Installation  l Concrete washout areas should be constructed as shown in the figures below, with a recom- mended minimum length and minimum width of 10 ft, but with sufficient quantity and volume to  contain all liquid and concrete waste generated by washout operations.  l Plastic lining material should be a minimum of 10 mil polyethylene sheeting and should be free  of holes, tears, or other defects that compromise the impermeability of the material.  l Lath and flagging should be commercial type.  l Liner seams shall be installed in accordance with manufacturers’ recommendations.  l Soil base shall be prepared free of rocks or other debris that may cause tears or holes in the  plastic lining material. Maintenance Standards Inspection and Maintenance  l Inspect and verify that concrete washout areas are in place prior to the commencement of con- crete work.  l Once concrete wastes are washed into the designated washout area and allowed to harden,  2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 the concrete should be broken up, removed, and disposed of per applicable solid waste reg- ulations. Dispose of hardened concrete on a regular basis.  l During periods of concrete work, inspect the concrete washout areas daily to verify continued  performance.  o Check overall condition and performance.  o Check remaining capacity (% full).  o If using self-installed concrete washout areas, verify plastic liners are intact and side- walls are not damaged.  o If using prefabricated containers, check for leaks.  l Maintain the concrete washout areas to provide adequate holding capacity with a minimum  freeboard of 12 inches.  l Concrete washout areas must be cleaned, or new concrete washout areas must be con- structed and ready for use once the concrete washout area is 75% full.  l If the concrete washout area is nearing capacity, vacuum and dispose of the waste material in  an approved manner.  l Do not discharge liquid or slurry to waterways, storm drains or directly onto ground.  l Do not discharge to the sanitary sewer without local approval.  l Place a secure, non-collapsing, non-water collecting cover over the concrete washout  area prior to predicted wet weather to prevent accumulation and overflow of pre- cipitation.  l Remove and dispose of hardened concrete and return the structure to a functional con- dition. Concrete may be reused on-site or hauled away for disposal or recycling.  l When you remove materials from a self-installed concrete washout area, build a new struc- ture; or, if the previous structure is still intact, inspect for signs of weakening or damage, and  make any necessary repairs. Re-line the structure with new  plastic after each cleaning. Removal of Concrete Washout Areas  l When concrete washout areas are no longer required for the work, the hardened concrete,  slurries and liquids shall be removed and properly disposed of.  l Materials used to construct concrete washout areas shall be removed from the site of the work  and disposed of or recycled.  l Holes, depressions or other ground disturbance caused by the removal of the concrete  washout areas shall be backfilled, repaired, and stabilized to prevent erosion. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Figure II-3.7: Concrete Washout Area with Wood Planks 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Figure II-3.8: Concrete Washout Area with Straw Bales 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Figure II-3.9: Prefabricated Concrete Washout Container w/Ramp 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Type of Inlet Pro- tection Emergency Overflow Applicable for Paved/ Earthen Sur- faces Conditions of Use Drop Inlet Protection Excavated  drop  inlet protection Yes, temporary  flooding may   occur Earthen Applicable for heavy flows. Easy   to maintain. Large area requirement:   30'x30'/acre Block  and gravel  drop inlet pro- tection Yes Paved or Earthen Applicable for heavy  concentrated flows.  Will not pond. Gravel and wire  drop inlet pro- tection No Paved or Earthen Applicable for  heavy concentrated flows.  Will pond. Can withstand traffic. Catch  basin filters Yes Paved or Earthen Frequent maintenance  required. Curb Inlet Protection Curb  inlet pro- tection with  wooden weir Small capacity  overflow Paved Used for sturdy, more compact  install- ation. Block and gravel  curb inlet pro- tection Yes Paved Sturdy, but  limited filtration. Culvert Inlet Protection Culvert  inlet sed- iment trap N/A N/A 18 month expected life. Table II-3.10: Storm Drain Inlet Protection Design and Installation Specifications Excavated Drop Inlet Protection Excavated drop inlet protection consists of an excavated impoundment around the storm drain inlet.  Sediment settles out of the stormwater prior to entering the storm drain. Design and installation spe- cifications for excavated drop inlet protection include:  l Provide a depth of 1-2 ft as measured from the crest of the inlet structure.  l Slope sides of excavation should be no steeper than 2H:1V.  l Minimum volume of excavation is 35 cubic yards.  l Shape the excavation to fit the site, with the longest dimension oriented toward the longest  inflow area.  l Install provisions for draining to prevent standing water.  l Clear the area of all debris. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3  l Grade the approach to the inlet uniformly.  l Drill weep holes into the side of the inlet.  l Protect weep holes with screen wire and washed aggregate.  l Seal weep holes when removing structure and stabilizing area.  l Build a temporary dike, if necessary, to the down slope side of the structure to prevent bypass  flow. Block and Gravel Filter A block and gravel filter is a barrier formed around the inlet with standard concrete blocks and gravel.  See Figure II-3.17: Block and Gravel Filter. Design and installation specifications for block gravel fil- ters include:  l Provide a height of 1 to 2 feet above the inlet.  l Recess the first row of blocks 2-inches into the ground for stability.  l Support subsequent courses by placing a pressure treated wood 2x4 through the block open- ing.  l Do not use mortar.  l Lay some blocks in the bottom row on their side to allow  for dewatering the pool.  l Place hardware cloth or comparable wire mesh with ½-inch openings over all block openings.  l Place gravel to just below the top of blocks on slopes of 2H:1V or flatter.  l An alternative design is a gravel berm surrounding the inlet, as follows:  o Provide a slope of 3H:1V on the upstream side of the berm.  o Provide a slope of 2H:1V on the downstream side of the berm.  o Provide a 1-foot wide level stone area between the gravel berm and the inlet.  o Use stones 3 inches in diameter or larger on the upstream slope of the berm.  o Use gravel ½- to ¾-inch at a minimum thickness of 1-foot on the downstream slope of  the berm. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Figure II-3.17: Block and Gravel Filter   2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Gravel and Wire Mesh Filter Gravel and wire mesh filters are gravel barriers placed over the top of the inlet. This method does not  provide an overflow. Design and installation specifications for gravel and wire mesh filters include:  l Use a hardware cloth or comparable wire mesh with ½-inch openings.  o Place wire mesh over the drop inlet so that the wire extends a minimum of 1-foot bey- ond each side of the inlet structure.  o Overlap the strips if more than one strip of mesh is necessary.  l Place coarse aggregate over the wire mesh.  o Provide at least a 12-inch depth of aggregate over the entire inlet opening and extend at  least 18-inches on all sides. Catch Basin Filters Catch  basin filters are designed by manufacturers for construction sites. The limited sediment stor- age capacity increases the amount of inspection and maintenance required, which may be daily for  heavy sediment loads. To reduce maintenance requirements, combine a catch  basin filter with  another type of inlet protection. This type of inlet protection provides flow  bypass without overflow  and therefore may be a better method for inlets located along active rights-of-way. Design and install- ation specifications for catch basin filters include:  l Provides 5 cubic feet of storage.  l Requires dewatering provisions.  l Provides a high-flow bypass that will not clog under normal use at a construction site.  l Insert the catch  basin filter in the catch  basin just below the grating. Curb Inlet Protection with Wooden Weir Curb inlet protection with wooden weir is an option that consists of a barrier formed around a curb  inlet with a wooden frame and gravel. Design and installation specifications for curb inlet protection  with wooden weirs include:  l Use wire mesh with ½-inch openings.  l Use extra strength filter cloth.  l Construct a frame.  l Attach the wire and filter fabric to the frame.  l Pile coarse washed aggregate against the wire and fabric.  l Place weight on the frame anchors. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Block and Gravel Curb Inlet Protection Block and gravel curb inlet protection is a barrier formed around a curb inlet with concrete blocks and  gravel. See Figure II-3.18: Block and Gravel Curb Inlet Protection. Design and installation spe- cifications for block and gravel curb inlet protection include:  l Use wire mesh with ½-inch openings.  l Place two concrete blocks on their sides abutting the curb at either side of the inlet opening.  These are spacer blocks.  l Place a 2x4 stud through the outer holes of each spacer block to align the front blocks.  l Place blocks on their sides across the front of the inlet and abutting the spacer blocks.  l Place wire mesh over the outside vertical face.  l Pile coarse aggregate against the wire to the top of the barrier. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Figure II-3.18: Block and Gravel Curb Inlet Protection   2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Curb and Gutter Sediment Barrier Curb and gutter sediment barrier is a sandbag or rock berm (riprap and aggregate) 3 feet high and 3  feet wide in a horseshoe shape. See Figure II-3.19: Curb and Gutter Barrier. Design and installation  specifications for curb and gutter sediment barrier include:  l Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap, 3 feet high  and 3 feet wide, at least 2 feet from the inlet.  l Construct a horseshoe shaped sedimentation trap on the upstream side of the berm. Size the  trap to sediment trap standards for protecting a culvert inlet. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Figure II-3.19: Curb and Gutter Barrier 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 BMP C233: Silt Fence Purpose Silt fence reduces the transport of coarse sediment from a construction site by providing a temporary  physical barrier to sediment and reducing the runoff velocities of overland flow. Conditions of Use Silt fence may be used downslope of all disturbed areas.  l Silt fence shall prevent sediment carried by runoff from going beneath, through, or over the  top of the silt fence, but shall allow the water to pass through the fence.  l Silt fence is not intended to treat concentrated flows, nor is it intended to treat substantial  amounts of overland flow. Convey any concentrated flows through the drainage system to a  sediment trapping BMP.  l Do not construct silt fences in streams or use in V-shaped ditches. Silt fences do not provide  an adequate method of silt control for anything deeper than sheet or overland flow. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Figure II-3.22: Silt Fence 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Design and Installation Specifications  l Use in combination with other construction stormwater BMPs.  l Maximum slope steepness (perpendicular to the silt fence line) 1H:1V.  l Maximum sheet or overland flow path length to the silt fence of 100 feet.  l Do not allow flows greater than 0.5 cfs.  l Use geotextile fabric that meets the following standards. All geotextile properties listed below  are minimum average roll values (i.e., the test result for any sampled roll in a lot shall meet or  exceed the values shown in Table II-3.11: Geotextile Fabric Standards for Silt Fence): Geotextile Property Minimum Average Roll Value Polymeric  Mesh AOS  (ASTM D4751) 0.60 mm maximum for slit film  woven (#30 sieve).  0.30 mm  maximum for all other geotextile types (#50 sieve).  0.15 mm minimum for all fabric  types (#100 sieve). Water  Permittivity  (ASTM D4491) 0.02 sec-1 minimum Grab  Tensile Strength  (ASTM D4632) 180 lbs. Minimum for extra  strength fabric.  100 lbs  minimum for standard strength fabric. Grab Tensile Strength  (ASTM D4632) 30% maximum Ultraviolet  Resistance  (ASTM D4355) 70%  minimum Table II-3.11: Geotextile Fabric Standards for Silt Fence  l Support standard strength geotextiles with wire mesh, chicken wire, 2-inch x 2-inch wire,  safety fence, or jute mesh to increase the strength of the geotextile. Silt fence materials are  available that have synthetic mesh backing attached.  l Silt fence material shall contain ultraviolet ray inhibitors and stabilizers to provide a minimum  of six months of expected usable construction life at a temperature range of 0°F to 120°F.  l One-hundred percent biodegradable silt fence is available that is strong, long lasting, and can  be left in place after the project is completed, if permitted by the local jurisdiction.  l Refer to Figure II-3.22: Silt Fence for standard silt fence details. Include the following Stand- ard Notes for silt fence on construction plans and specifications:  1. The Contractor shall install and maintain temporary silt fences at the locations shown in  the Plans.  2. Construct silt fences in areas of clearing, grading, or drainage prior to starting those  activities. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3  3. The silt fence shall have a 2-feet min. and a 2½-feet max. height above the original  ground surface.  4. The geotextile fabric shall be sewn together at the point of manufacture to form fabric  lengths as required. Locate all sewn seams at support posts. Alternatively, two sections  of silt fence can be overlapped, provided  that the overlap is long enough and that the  adjacent silt fence sections are close enough together to prevent silt laden water from  escaping through the fence at the overlap.  5. Attach the geotextile fabric on the up-slope side of the posts and secure with staples,  wire, or in accordance with the manufacturer's recommendations. Attach the geotextile  fabric to the posts in a manner that reduces the potential for tearing.  6. Support the geotextile fabric with wire or plastic mesh, dependent on the properties of  the geotextile selected for use. If wire or plastic mesh is used, fasten the mesh securely  to the up-slope side of the posts with the geotextile fabric up-slope of the mesh.  7. Mesh support, if used, shall consist of steel wire with a maximum mesh spacing of 2- inches, or a prefabricated polymeric mesh. The strength of the wire or polymeric mesh  shall be equivalent to or greater than 180 lbs. grab tensile strength. The polymeric mesh  must be as resistant to the same level of ultraviolet radiation as the geotextile fabric it  supports.  8. Bury the bottom of the geotextile fabric 4-inches min. below the ground surface. Backfill  and tamp soil in place over the buried portion of the geotextile fabric, so that no flow can  pass beneath the silt fence and scouring cannot occur. When wire or polymeric back-up  support mesh is used, the wire or polymeric mesh shall extend into the ground 3-inches  min.  9. Drive or place the silt fence posts into the ground 18-inches min. A 12–inch min. depth  is allowed if topsoil or other soft subgrade soil is not present and 18-inches cannot be  reached. Increase fence post min. depths by 6 inches if the fence is located on slopes of  3H:1V or steeper and the slope is perpendicular to the fence. If required post depths  cannot be obtained, the posts shall be adequately secured by bracing or guying to pre- vent overturning of the fence due to sediment loading.  10. Use wood, steel or equivalent posts. The spacing of the support posts shall be a max- imum of 6-feet. Posts shall consist of either:  l Wood with minimum dimensions of 2 inches by 2 inches by 3 feet. Wood shall be  free of defects such as knots, splits, or gouges.  l No. 6 steel rebar or larger.  l ASTM A 120 steel pipe with a minimum diameter of 1-inch.  l U, T, L, or C shape steel posts with a minimum weight of 1.35 lbs./ft.  l Other steel posts having equivalent strength and bending resistance to the post  sizes listed above.  11. Locate silt fences on contour as much as possible, except at the ends of the fence,  2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 where the fence shall be turned uphill such that the silt fence captures the runoff water  and prevents water from flowing around the end of the fence.  12. If the fence must cross contours, with the exception of the ends of the fence, place  check dams perpendicular to the back of the fence to minimize concentrated flow and  erosion. The slope of the fence line where contours must be crossed shall not be  steeper than 3H:1V.  l Check dams shall be approximately 1-foot deep at the back of the fence. Check  dams shall be continued perpendicular to the fence at the same elevation until  the top of the check dam intercepts the ground surface behind the fence.  l Check dams shall consist of crushed surfacing base course, gravel backfill for  walls, or shoulder ballast. Check dams shall be located every 10 feet along the  fence where the fence must cross contours.  l Refer to Figure II-3.23: Silt Fence Installation by Slicing Method for slicing method details. The  following are specifications for silt fence installation using the slicing method:  1. The base of both end posts must be at least 2- to 4-inches above the top of the geo- textile fabric on the middle posts for ditch checks to drain properly. Use a hand level or  string level, if necessary, to mark base points before installation.  2. Install posts 3- to 4-feet apart in critical retention areas and 6- to 7-feet apart in standard  applications.  3. Install posts 24-inches deep on the downstream side of the silt fence, and as close as  possible to the geotextile fabric, enabling posts to support the geotextile fabric from  upstream water pressure.  4. Install posts with the nipples facing away from the geotextile fabric.  5. Attach the geotextile fabric to each post with three ties, all spaced within the top 8- inches of the fabric. Attach each tie diagonally 45 degrees through the fabric, with each  puncture at least 1-inch vertically apart. Each tie should be positioned to hang on a post  nipple when tightening to prevent sagging.  6. Wrap approximately 6-inches of the geotextile fabric around the end posts and secure  with 3 ties.  7. No more than 24-inches of a 36-inch geotextile fabric is allowed above ground level.  8. Compact the soil immediately next to the geotextile fabric with the front wheel of the  tractor, skid steer, or roller exerting at least 60 pounds per square inch. Compact the  upstream side first and then each side twice for a total of four trips. Check and correct  the silt fence installation for any deviation before compaction. Use a flat-bladed shovel  to tuck the fabric deeper into the ground if necessary. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Figure II-3.23: Silt Fence Installation by Slicing Method 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 Maintenance Standards  l Repair any damage immediately.  l Intercept and convey all evident concentrated flows uphill of the silt fence to a sediment trap- ping BMP.  l Check the uphill side of the silt fence for signs of the fence clogging and acting as a barrier to  flow  and then causing channelization of flows parallel to the fence. If this occurs, replace the  fence and remove the trapped sediment.  l Remove sediment deposits when the deposit reaches approximately one-third the height of  the silt fence, or install a second silt fence.  l Replace geotextile fabric that has deteriorated due to ultraviolet breakdown. 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 2019 Stormwater Management Manual for Western Washington Volume II -Chapter 3 C. Site Inspection Form D. Construction Stormwater General Permit (CSWGP) (To be included once CSWGP is issued.) E. Engineering Calculations (Included in the Technical Information Report.)