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HomeMy WebLinkAboutRS_APPROVED Construction SWPPP_20210602.pdf i Stormwater Pollution Prevention Plan For 7th Street Short Plat Prepared For Jagadeshwar Gattu Owner Developer Operator/Contractor Jagadeshwar Gattu same as owner TBD 14716 NE 76th Street Redmond, WA 98052 Project Site Location 3605 NE 7th Street Renton, WA 98056 Certified Erosion and Sediment Control Lead TBD SWPPP Prepared By Lori L. Harvey, CESCL Senior Land Planner - Special Projects Senior Site Inspector SWPPP Preparation Date June 29, 2020 Revised September 17, 2020 Approximate Project Construction Dates November 15, 2020 through June 1, 2021 DEVELOPMENT ENGINEERING Nathan Janders 05/25/2021 ii Contents 1.0 Introduction ...............................................................................................................................1  2.0 Site Description ........................................................................................................................3  2.1 Existing Conditions ...........................................................................................................3  2.2 Proposed Construction Activities ......................................................................................3  3.0 Construction Stormwater BMPs ...............................................................................................5  3.1 The 13 BMP Elements .......................................................................................................5  3.1.1 Element #1 – Mark Clearing Limits ...................................................................5  3.1.2 Element #2 – Establish Construction Access .....................................................5  3.1.3 Element #3 – Control Flow Rates.......................................................................6  3.1.4 Element #4 – Install Sediment Controls .............................................................7  3.1.5 Element #5 – Stabilize Soils ...............................................................................9  3.1.6 Element #6 – Protect Slopes .............................................................................10  3.1.7 Element #7 – Protect Drain Inlets.....................................................................12  3.1.8 Element #8 – Stabilize Channels and Outlets ...................................................13  3.1.9 Element #9 – Control Pollutants .......................................................................14  3.1.10 Element #10 – Control Dewatering .................................................................17  3.1.11 Element #11 – Maintain BMPs .......................................................................19  3.1.12 Element #12 – Manage the Project ..................................................................19  3.1.13 Element #13 Protect Low Impact Development BMPS ....................................22  3.2 Site Specific BMPs ...........................................................................................................23  3.3 Additional Advanced BMPs .............................................................................................23  4.0 Construction Phasing and BMP Implementation .............................................................23  5.0 Pollution Prevention Team ......................................................................................................24  5.1 Roles and Responsibilities ...............................................................................................24  5.2 Team Members ................................................................................................................25  6.0 Site Inspections and Monitoring .............................................................................................26  6.1 Site Inspection .................................................................................................................26  6.1.1 Site Inspection Frequency ................................................................................27  6.1.2 Site Inspection Documentation .........................................................................27  6.2 Stormwater Quality Monitoring ......................................................................................27  6.2.1 Turbidity Sampling ...........................................................................................27  7.0 Reporting and Recordkeeping ................................................................................................30  7.1 Recordkeeping .................................................................................................................30  7.1.1 Site Log Book ...................................................................................................30  7.1.2 Records Retention.............................................................................................31  7.1.3 Access to Plans and Records ............................................................................31  7.1.4 Updating the SWPPP ........................................................................................31  iii 7.2 Reporting .........................................................................................................................31  7.2.1 Discharge Monitoring Reports .........................................................................31  7.2.2 Notification of Noncompliance ........................................................................31  Appendix A – Site Plans .........................................................................................................33  Appendix B - Spill Prevention, Control, and Countermeasure (SPCC) Plan .........................34  Appendix C – Environment Constraints and Impaired Body Conditions ..............................35  Appendix D – General Permit ................................................................................................36  Appendix E – Site Inspection Forms (and Site Log) ..............................................................37  Appendix F – Reports and Engineering Calculations .............................................................39  Appendix G – Best Management Practices (BMPs) ...............................................................40  Appendix A Site plans Appendix B Spill Prevention, Control, and Countermeasure (SPCC) Plan Appendix C Environmental Constraints and Impaired Body Conditions Appendix D General Permit Appendix E Site Log and Inspection Forms Appendix F Reports and Engineering Calculations Appendix G Best Management Practices Stormwater Pollution Prevention Plan 1 1.0 Introduction The introduction should include the following information:  Project site name  Brief site description  Brief description of the proposed project (what/when)  Proposed objective of the SWPPP (SWPPP objectives 1-3)  Reference to the Stormwater Manual used in preparation of the SWPPP  Organization of the SWPPP The project, 7th Street Short Plat is the formal platting of one existing tax parcel into 3 single family residential lots. The project is not subject to coverage under the Construction General Stormwater Permit as administered by Ecology as it is under 1 acre in size. For the purposes of this SWPPP all 0.64 acres will be considered disturbed. The purpose of this SWPPP is to describe the proposed construction activities and all temporary and permanent erosion and sediment control (TESC) measures, pollution prevention measures, inspection/monitoring activities, and recordkeeping that will be implemented during the proposed construction project. The objectives of the SWPPP are to: 1. Implement Best Management Practices (BMPs) to prevent erosion and sedimentation, and to identify, reduce, eliminate or prevent stormwater contamination and water pollution from construction activity. 2. Prevent violations of surface water quality, ground water quality, or sediment management standards. 3. Prevent, during the construction phase, adverse water quality impacts including impacts on beneficial uses of the receiving water by controlling peak flow rates and volumes of stormwater runoff at the Permittee’s outfalls and downstream of the outfalls. This SWPPP was prepared based on the requirements set forth in the Construction Stormwater General Permit and to the design standards of 2017 City of Renton Surface Water Design Manual and its amendments to the 2016 King County Surface Water Design Manual. The Stormwater Pollution Prevention Plan 2 report is divided into seven main sections with several appendices that include stormwater related reference materials. The topics presented in the each of the main sections are:  Section 1 – INTRODUCTION. This section provides a summary description of the project, and the organization of the SWPPP document.  Section 2 – SITE DESCRIPTION. This section provides a detailed description of the existing site conditions, proposed construction activities, and calculated stormwater flow rates for existing conditions and post– construction conditions.  Section 3 – CONSTRUCTION BMPs. This section provides a detailed description of the BMPs to be implemented based on the 12 required elements of the SWPPP (SWMMEW 2004).  Section 4 – CONSTRUCTION PHASING AND BMP IMPLEMENTATION. This section provides a description of the timing of the BMP implementation in relation to the project schedule.  Section 5 – POLLUTION PREVENTION TEAM. This section identifies the appropriate contact names (emergency and non-emergency), monitoring personnel, and the onsite temporary erosion and sedimentation control inspector  Section 6 – INSPECTION AND MONITORING. This section provides a description of the inspection and monitoring requirements such as the parameters of concern to be monitored, sample locations, sample frequencies, and sampling methods for all stormwater discharge locations from the site.  Section 7 – RECORDKEEPING. This section describes the requirements for documentation of the BMP implementation, site inspections, monitoring results, and changes to the implementation of certain BMPs due to site factors experienced during construction. Supporting documentation and standard forms are provided in the following Appendices: Appendix A – Site plans Appendix B – Spill Prevention, Control, and Countermeasure (SPCC) Plan Appendix C – Environmental Constraints and Impaired Body Conditions Appendix D – General Permit Appendix E – Site Log and Inspection Forms Appendix F – Reports and Engineering Calculations Stormwater Pollution Prevention Plan 3 2.0 Site Description 2.1 Existing Conditions Description of Site (location, size, existing structure, topography, typical soil and groundwater characteristics): The 7th Street Short Plat project is located at 3605 NE 7th Street, Renton, WA 98056, in the jurisdictional boundary of the City of Renton (King County Tax Parcel# 8011100135). The 0.64 acre site is best described as rectangular and contains one single family home with associated out buildings. All existing structure are to be proposed to be demolished. The site slopes from the east to the west at an approximate gradient ranging from 5% to 10% with isolated areas up to 30%. According to Natural Resources Conservation Service (NRCS), site soils consist of Arents, Alderwood material, 6 to 15 percent slopes. According to the Geotechnical report conducted by Earth Solutions NW, LLC (ESNW) on August 20, 2018, the native soils were classified primarily as silty sand with gravel, consistent with the typical makeup of glacial till deposits Description of drainage (on site runoff conveyance and downstream receiving water bodies and drainage systems): Under both preexisting and post developed conditions stormwater flows southwesterly to an exisiting conveyance system located in NE 7th Place. From NE 7th Place, runoff continues through an existing closed conveyance system with eventual discharge to Cedar River, tributary to Lake Washington. Description of critical areas (high erosion risk areas, wetland/stream/shoreline areas, steep slopes and landslide prone areas): There are no identifed critial areas on site. 2.2 Proposed Construction Activities Provide the following mandatory information in the narrative section below:  Description of site development Stormwater Pollution Prevention Plan 4  Description of construction activities  Description of site drainage  Description of final site soil stabilization, revegetation, etc Site development will include but may not be limited to: setting clearing limits, installation of BMPs, logging, clearing, grading, construction of right of way and right of way peripherals (curb, gutters, asphalt, mailboxes, street lighting, street signage and striping), construction of utilities (electricity, cable, phone, storm, sewer, water), followed by home construction. No runof peak flows were calculated for this project. The following section includes data when available The following summarizes details regarding site areas:  Total site area: 0.64 acres  Percent impervious area before construction: +/- 10%  Percent impervious area after construction (Averaged) 29.86 %  Disturbed area during construction: 0.64acres  Disturbed area that is characterized as impervious (i.e., access roads, staging, parking): +/- 0.05 acres  2-year stormwater runoff peak flow prior to construction (existing): NAcfs  10-year stormwater runoff peak flow prior to construction (existing): NAcfs  2-year stormwater runoff peak flow during construction: NAcfs  10-year stormwater runoff peak flow during construction: NAcfs  2-year stormwater runoff peak flow after construction: NAcfs  10-year stormwater runoff peak flow after construction: NAcfs All stormwater flow calculations are provided in Appendix F. Stormwater Pollution Prevention Plan 5 3.0 Construction Stormwater BMPs 3.1 The 13 BMP Elements 3.1.1 Element #1 – Mark Clearing Limits To protect adjacent properties and to reduce the area of soil exposed to construction, the limits of construction will be clearly marked before land-disturbing activities begin. Trees that are to be preserved, as well as all sensitive areas and their buffers, shall be clearly delineated, both in the field and on the plans. In general, natural vegetation and native topsoil shall be retained in an undisturbed state to the maximum extent possible. The BMPs relevant to marking the clearing limits that will be applied for this project include: Preserving Natural Vegetation (BMP C101) Buffer Zones (BMP C102) High Visibility Plastic or Metal Fence (BMP C103) Silt Fence (BMP C233) Alternate BMPs have been left unchecked above. To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed above after the first sign that existing BMPs are ineffective or failing. 3.1.2 Element #2 – Establish Construction Access Construction access or activities occurring on unpaved areas shall be minimized, yet where necessary, access points shall be stabilized to minimize the tracking of sediment onto public roads, and wheel washing, street sweeping, and street cleaning shall be employed to prevent sediment from entering state waters. All wash wastewater shall be controlled on site. The specific BMPs related to establishing construction access that will be used on this project include: Stormwater Pollution Prevention Plan 6 Stabilized Construction Entrance (BMP C105) Wheel Wash (BMP C106) Construction Road/Parking Area Stabilization (BMP C107) Alternate BMPs have been left unchecked above. To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed above after the first sign that existing BMPs are ineffective or failing. 3.1.3 Element #3 – Control Flow Rates To protect the properties and waterways downstream of the project site, stormwater discharges from the site will be controlled. The specific BMPs for flow control that shall be used on this project include: Sediment Trap (BMP C240) Water Bars (BMP C203) Check Dams (BMP C207) Outlet Protection (BMP C209) Wattles (BMP C235) Stormwater Pollution Prevention Plan 7 Temporary Sediment Pond (BMP C241) Alternate BMPs have been left unchecked above. To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed above after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, the project must comply with Minimum Requirement 7 (Ecology ). In general, discharge rates of stormwater from the site will be controlled where increases in impervious area or soil compaction during construction could lead to downstream erosion, or where necessary to meet local agency stormwater discharge requirements. 3.1.4 Element #4 – Install Sediment Controls All stormwater runoff from disturbed areas shall pass through an appropriate sediment removal BMP before leaving the construction site or prior to being discharged to an infiltration facility. The specific BMPs to be used for controlling sediment on this project include: Brush Barrier (BMP C231) Gravel Filter Berm (BMP C232) Silt Fence (BMP C233) Vegetated Strip (BMP C234) Wattles (BMP C235) Stormwater Pollution Prevention Plan 8 Sediment Trap (BMP C240) Temporary Sediment Pond (BMP C241) Construction Stormwater Chemical Treatment (BMP C250) Construction Stormwater Filtration (BMP C251) Alternate BMPs have been left unchecked above. To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed above after the first sign that existing BMPs are ineffective or failing. In addition, sediment will be removed from paved areas in and adjacent to construction work areas manually or using mechanical sweepers, as needed, to minimize tracking of sediments on vehicle tires away from the site and to minimize washoff of sediments from adjacent streets in runoff. Whenever possible, sediment laden water shall be discharged into onsite, relatively level, vegetated areas (BMP C240 paragraph 5, page 4-102). In some cases, sediment discharge in concentrated runoff can be controlled using permanent stormwater BMPs (e.g., infiltration swales, ponds, trenches). Sediment loads can limit the effectiveness of some permanent stormwater BMPs, such as those used for infiltration or biofiltration; however, those BMPs designed to remove solids by settling (wet ponds or detention ponds) can be used during the construction phase. When permanent stormwater BMPs will be used to control sediment discharge during construction, the structure will be protected from excessive sedimentation with adequate erosion and sediment control BMPs. Any accumulated sediment shall be removed after construction is complete and the permanent stormwater BMP will be restabilized with vegetation per applicable design requirements once the remainder of the site has been stabilized. Stormwater Pollution Prevention Plan 9 3.1.5 Element #5 – Stabilize Soils Exposed and unworked soils shall be stabilized with the application of effective BMPs to prevent erosion throughout the life of the project. The specific BMPs for soil stabilization that shall be used on this project include: Temporary and Permanent Seeding (BMP C120) Mulching (BMP C121) Nets and Blankets (BMP C122) Plastic Covering (BMP C123) Sodding (BMP C124) Topsoiling/Composting (BMP C125) Polyacrylamide for Soil Erosion Protection (BMP C126) Surface Roughening (BMP C130) Gradient Terraces (BMP C131) Dust Control (BMP C140) Stormwater Pollution Prevention Plan 10 Early application of gravel base on areas to be paved Materials on Hand (BMP C150) may also be applicable. Alternate BMPs have been left unchecked above. To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed above after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, no soils shall remain exposed and unworked for more than 7 days during the dry season (May 1 to September 30) and 2 days during the wet season (October 1 to April 30). Regardless of the time of year, all soils shall be stabilized at the end of the shift before a holiday or weekend if needed based on weather forecasts. The In general, cut and fill slopes will be stabilized as soon as possible and soil stockpiles will be temporarily covered with plastic sheeting. All stockpiled soils shall be stabilized from erosion, protected with sediment trapping measures, and where possible, be located away from storm drain inlets, waterways, and drainage channels. 3.1.6 Element #6 – Protect Slopes All cut and fill slopes will be designed, constructed, and protected in a manner that minimizes erosion. The following specific BMPs will be used to protect slopes for this project: Temporary and Permanent Seeding (BMP C120) Mulching (BMP C121) Nets and Blankets (BMP C122) Stormwater Pollution Prevention Plan 11 Surface Roughening (BMP C131) Gradient Terraces (BMP C131) Interceptor Dike and Swale (BMP C200) Grass-Lined Channels (BMP C201) Water Bars (BMP C203) Pipe Slope Drains (BMP C204) Subsurface Drains (BMP C205) Level Spreader (BMP C206) Check Dams (BMP C207) Triangular Silt Dike (Geotextile-Encased Check Dams) (BMP C208) Plastic sheeting may be used on cut slopes. See construction plans for King County detail Stormwater Pollution Prevention Plan 12 Alternate BMPs have been left unchecked above. To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed above after the first sign that existing BMPs are ineffective or failing. 3.1.7 Element #7 – Protect Drain Inlets All storm drain inlets and culverts made operable during construction shall be protected to prevent unfiltered or untreated water from entering the drainage conveyance system. However, the first priority is to keep all access roads clean of sediment and keep street wash water separate from entering storm drains until treatment can be provided. Storm Drain Inlet Protection (BMP C220) will be implemented for all drainage inlets and culverts that could potentially be impacted by sediment-laden runoff on and near the project site. The following inlet protection measures will be applied on this project: Drop Inlet Protection Excavated Drop Inlet Protection Block and Gravel Drop Inlet Protection Gravel and Wire Drop Inlet Protection Catch Basin Filters Alternative BMP not included in the SWMMWW (2012) SWMMEW (2004) Curb Inlet Protection Wooden Weir Stormwater Pollution Prevention Plan 13 Block and Gravel Inlet Protection Alternative BMP not included in SWMMWW (2012) Culvert Inlet Protection Culvert Inlet Sediment Trap Alternative BMP not included in SWMMWW (2012) Alternate BMPs have been left unchecked above. To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed above after the first sign that existing BMPs are ineffective or failing. 3.1.8 Element #8 – Stabilize Channels and Outlets Where site runoff is to be conveyed in channels, or discharged to a stream or some other natural drainage point, efforts will be taken to prevent downstream erosion. The specific BMPs for channel and outlet stabilization that shall be used on this project include: Channel Lining (BMP C202) Nets and Blankets (BMP C122) Check Dams (BMP C207) Stormwater Pollution Prevention Plan 14 Outlet Protection (BMP C209) Alternate BMPs have been left unchecked above. To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed above after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, all temporary on-site conveyance channels shall be designed, constructed, and stabilized to prevent erosion from the expected peak 10 minute velocity of flow from a Type 1A, 10-year, 24-hour recurrence interval storm for the developed condition. Alternatively, the 10-year, 1-hour peak flow rate indicated by an approved continuous runoff simulation model, increased by a factor of 1.6, shall be used. Stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent streambanks, slopes, and downstream reaches shall be provided at the outlets of all conveyance systems. 3.1.9 Element #9 – Control Pollutants All pollutants, including waste materials and demolition debris, that occur onsite shall be handled and disposed of in a manner that does not cause contamination of stormwater. Good housekeeping and preventative measures will be taken to ensure that the site will be kept clean, well organized, and free of debris. If required, BMPs to be implemented to control specific sources of pollutants are discussed below. Concrete Handling (BMP C151) Sawcutting and Surfacing Pollution Prevention (BMP C152) Material Delivery, Storage and Containment (BMP C153) Concrete Washout Area (BMP C154) Stormwater Pollution Prevention Plan 15 Construction Stormwater Chemical Treatment (BMP C250) Construction Stormwater Filtration (BMP C251) High pH Neutralization Using CO2 (BMP C252) pH Control for High pH Water (BMP C253) Vehicles, construction equipment, and/or petroleum product storage/dispensing:  All vehicles, equipment, and petroleum product storage/dispensing areas will be inspected regularly to detect any leaks or spills, and to identify maintenance needs to prevent leaks or spills.  On-site fueling tanks and petroleum product storage containers shall include secondary containment.  Spill prevention measures, such as drip pans, will be used when conducting maintenance and repair of vehicles or equipment.  In order to perform emergency repairs on site, temporary plastic will be placed beneath and, if raining, over the vehicle.  Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. Chemical Storage:  Any chemicals stored in the construction areas will conform to the appropriate source control BMPs listed in Volume IV of the Ecology stormwater manual. In western WA, all chemicals shall have cover, Stormwater Pollution Prevention Plan 16 containment, and protection provided on site, Per BMP C153 for Material Delivery, Storage and Containment in SWMMWW 2012  Application of agricultural chemicals, including fertilizers and pesticides shall be conducted in a manner and at application rates that will not result in loss of chemical to stormwater runoff. Manufacturers’ recommendations for application procedures and rates shall be followed. Excavation and tunneling spoils dewatering waste:  Dewatering BMPs and BMPs specific to the excavation and tunneling (including handling of contaminated soils) are discussed under Element 10 Demolition:  Dust released from demolished sidewalk. Building, or structures will be controlled using Dust Control Measures (BMP C140)  Storm drain inlets vulnerable to stormwater discharge carrying dust, soil, or debris will be protected using Storm Drain Inlet Protection (BMP C220 as described in Element 7).  Process water and slurry resulting from sawcutting and surfacing operations will be prevented from entering the waters of the State by implementing Sawcutting and surfacing Pollution Prevention measures (BMP C152) Concrete and grout:  Process water and slurry resulting from concrete work will be prevented from entering the waters of the State by implementing Concrete Handling measures (BMP C151) Sanitary wastewater:  Portable sanitation facilities will be firmly secured, regularly maintained, and empties when necessary  Wheel wash or tire bath wastewater shall be discharged to a separate on- site treatment system or to the sanitary sewer as part of the Wheel Wash Implementation (BMP C106) Solid waste:  Solid waste will be stored in secure, clearly marked containers Stormwater Pollution Prevention Plan 17 Other:  Other BMPs will be administered as necessary to address any additional pollutant sources on site. The facility: IS transportation-related and therefore subject to the criteria for determining if a Spill Prevention, Control, and Countermeasure (SPCC) Plan is required under the Federal regulations of the Clean Water Act (CWA). If applicable, the Contractor shall prepare an SPCC Plan according to the Washington State Department of Transportation (WSDOT) Requirements (see the WASDOT Standards Specifications for Road, Bridge, and Municipal Construction 2004). See Appendix C for the SPCC Plan and requirements. As per the Federal regulations for the Clean Water Act (CWA) and according to the Final Rule 40 CFR Part 112, as stated in the National Register, a Spill Prevention, Control, and Countermeasure (SPCC) Plan is required for construction activities. A SPCC Plan has been prepared to address an approached to prevent, respond to, and report spills or releases to the environment that could result from construction activities. This Plan must:  Be well thought out in accordance with good engineering;  Achieve three objectives – prevent spills, contain a spill that occurs, and clean up the spill;  Identify the name, location, owner, and type of facility;  Include the date of initial operation and oil spill history;  Name the designated person responsible;  Show evidence of approval and certification by the person in authority; and  Contain a facility analysis IS NOT transportation related and therefore will not require a Spill Prevention, Control, and Countermeasure (SPCC) Plan under the Federal regulations of the Clean Water Act (CWA). 3.1.10 Element #10 – Control Dewatering All dewatering water from open cut excavation, tunneling, foundation work, trench, or underground vaults shall be discharges into a controlled conveyance system prior to discharge to the sediments trap or sediment pond. Channels will be stabilized, per Element #8. Clean, non- Stormwater Pollution Prevention Plan 18 turbid dewatering water will not be routed through stormwater sediment ponds, and will be discharges to systems tributary to the receiving waters of the State in a manner that does not cause erosion, flooding, or a violation of State water quality standards in the receiving water. Highly turbid dewatering water from soils known or suspected to be contaminated, or from use of construction equipment, will require additional monitoring a treatment as required for the specific pollutants based on the receiving waters into which the discharge is occurring. Such monitoring is the responsibility of the contractor However, the dewatering of soils known to be free of contamination will trigger BMPs to trap sediment and reduce turbidity. At a minimum, Geotextile fabric socks/bags/cells will be used to filter this material. Other BMPs to be used for sediment trapping and turbidity reduction include the following: Concrete Handling (BMP C151) Temporary Sediment Pond (BMP C241) Construction Stormwater Chemical Treatment (BMP C250) Construction Stormwater Filtration (BMP C251) Infiltration Use of sedimentation bag, with outfall to a ditch or swale for small volumes of water Water Bars (BMP C203) Vegetation Filtration (BMP C236) Stormwater Pollution Prevention Plan 19 No dewatering is proposed nor anticipated Alternate BMPs have been left unchecked above. To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed above after the first sign that existing BMPs are ineffective or failing. 3.1.11 Element #11 – Maintain BMPs All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each BMP specification (attached). Visual monitoring of the BMPs 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 will be reduced to once every month. All temporary erosion and sediment control BMPs shall be removed within 30 days after the final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil resulting from removal of BMPs or vegetation shall be permanently stabilized. Materials on Hand (BMP C150) Certified Erosion and Sediment Control Lead (BMP C160) 3.1.12 Element #12 – Manage the Project Erosion and sediment control BMPs for this project have been designed based on the following principles:  Design the project to fit the existing topography, soils, and drainage patterns.  Emphasize erosion control rather than sediment control.  Minimize the extent and duration of the area exposed. Stormwater Pollution Prevention Plan 20  Keep runoff velocities low.  Retain sediment on site.  Thoroughly monitor site and maintain all ESC measures.  Schedule major earthwork during the dry season. In addition, project management will incorporate the key components listed below: As this project site is located west of the Cascade Mountain Crest, the project will be managed according to the following key project components: Phasing of Construction  The construction project is being phased to the extent practicable to prevent soil erosion, and, to the maximum extent possible, the transport of sediment from the site during construction.  Revegetation of exposed areas and maintenance of that vegetation shall be an integral part of the clearing activities during each phase of construction, per the Scheduling BMP (C 162). Seasonal Work Limitations  From October 1 through April 30, clearing, grading, and other soil disturbing activities shall only be permitted if shown to the satisfaction of the local permitting authority that silt-laden runoff will be prevented from leaving the site through a combination of the following:  Site conditions including existing vegetative coverage, slope, soil type, and proximity to receiving waters; and  Limitations on activities and the extent of disturbed areas; and  Proposed erosion and sediment control measures.  Based on the information provided and/or local weather conditions, the local permitting authority may expand or restrict the seasonal limitation on site disturbance.  The following activities are exempt from the seasonal clearing and grading limitations: Stormwater Pollution Prevention Plan 21  Routine maintenance and necessary repair of erosion and sediment control BMPs;  Routine maintenance of public facilities or existing utility structures that do not expose the soil or result in the removal of the vegetative cover to soil; and  Activities where there is 100 percent infiltration of surface water runoff within the site in approved and installed erosion and sediment control facilities. Coordination with Utilities and Other Jurisdictions  Care has been taken to coordinate with utilities, other construction projects, and the local jurisdiction in preparing this SWPPP and scheduling the construction work. Inspection and Monitoring  All BMPs shall be inspected, maintained, and repaired as needed to assure continued performance of their intended function. Site inspections shall be conducted by a person who is knowledgeable in the principles and practices of erosion and sediment control. This person has the necessary skills to:  Assess the site conditions and construction activities that could impact the quality of stormwater, and  Assess the effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges.  A Certified Erosion and Sediment Control Lead shall be on-site or on-call always.  Whenever inspection and/or monitoring reveals that the BMPs identified in this SWPPP are inadequate, due to the actual discharge of or potential to discharge a significant amount of any pollutant, appropriate BMPs or design changes shall be implemented as soon as possible. Maintaining an Updated Construction SWPPP  This SWPPP shall be retained on-site or within reasonable access to the site. Stormwater Pollution Prevention Plan 22  The SWPPP shall be modified whenever there is a change in the 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 shall be modified if, during inspections or investigations conducted by the owner/operator, or the applicable local or state regulatory authority, it is determined that the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. The SWPPP shall be modified as necessary to include additional or modified BMPs designed to correct problems identified. Revisions to the SWPPP shall be completed within seven (7) days following the inspection. 3.1.13 Element #13 Protect Low Impact Development BMPS Buffer Zone (BMP C102) High Visibility Fence (BMP C103) Interceptor Dike and Swale (BMP C200) Grass-Lined Channels (BMP C201) Check Dams (BMP C207) Triangular Silt Dike (TSD) (Geotextile-Encased Check Dams) (BMP C208) Brush Barrier (BMP C231) Silt Fence (BMP C233) Stormwater Pollution Prevention Plan 23 Vegetated Strip (BMP C234) The project is not subject to LID 3.2 Site Specific BMPs Site specific BMPs are shown on the TESC Plan sheets and details in Appendix A. These site- specific plan sheet will be updated annually. All BMPs unchecked are to be considered as alternative and subject to field change 3.3 Additional Advanced BMPs The following BMPS are advances and are only recommend if construction activities are complex enough to warrant the; or if the site has the potential for significant impact to water quality. The following BMPs are directed at end of pipe treatment for sedimentation issues related to turbid runoff from construction sites. Effective BMPs are most often the simple BMPs, and focus on the minimization of erosion before sedimentation is an issue. The following BMPs will most likely be implemented only after other BMP options are exhausted, or if the construction activity is large and off-site sedimentation or turbid run off occur or is inevitable. BMP 250: Use of BMP 250 requires written pre-approval through Ecology BMP C250: Construction Stormwater Chemical Treatment BMP C250: Construction Stormwater Filtration 4.0 Construction Phasing and BMP Implementation The following section requires site specific information based on the BMPs selected in Section 3. Some upfront schedule information was input from the SWPPP Wizard, but additional site- specific dates and scheduling information is required. This section must convey key information on the project schedule and how the BMPs will be implemented within the schedule. The BMP implementation schedule will be driven by the construction schedule. The following provides a sequential list of the proposed construction schedule milestones and the corresponding BMP implementation schedule. The list contains key milestones such as wet season construction. Stormwater Pollution Prevention Plan 24 The BMP implementation schedule listed below is keyed to proposed phases of the construction project, and reflects differences in BMP installations and inspections that relate to wet season construction. The project site is located west of the Cascade Mountain Crest. As such, the dry season is from May 1 to September 30 and the wet season is from October 1 to April 30. The following construction sequence timing is based upon an estimate of activities:  Arrange and Attend Preconstruction Meeting Day 1  Flag and fence clearing limits Day 2-5  Install filter fabric fence Day 6  Install construction entrance Day 7  Preserve and protect all wetlands and buffers Day 8-9  Install Erosion Control measures Day 9-10  Clear and grade site Day 11-31  Construct Storm Facilities Day 31-51  Install Sewer, water and dry utilities Day 51-61  Install Catch Basins and conveyance pipes Day 61-71  Construct roof and yard drains Day 61-71  Install concrete curb Day 71-75  Remove construction entrance, asphalt road Day 75-80  Construct Sidewalk Day 80-83  Call for inspections Day 85  Begin home construction Day 90 5.0 Pollution Prevention Team 5.1 Roles and Responsibilities The pollution prevention team consists of personnel responsible for implementation of the SWPPP, including the following:  Certified Erosion and Sediment Control Lead (CESCL) – primary contractor contact, responsible for site inspections (BMPs, visual Stormwater Pollution Prevention Plan 25 monitoring, sampling, etc.); to be called upon in case of failure of any ESC measures.  Resident Engineer – For projects with engineered structures only (sediment ponds/traps, sand filters, etc.): site representative for the owner that is the project's supervising engineer responsible for inspections and issuing instructions and drawings to the contractor's site supervisor or representative  Emergency Ecology Contact – individual to be contacted at Ecology in case of emergency. Go to the following website to get the name and number for the Ecology contact information: http://www.ecy.wa.gov/org.html.  Emergency Owner Contact – individual that is the site owner or representative of the site owner to be contacted in the case of an emergency.  Non-Emergency Ecology Contact – individual that is the site owner or representative of the site owner than can be contacted if required.  Monitoring Personnel – personnel responsible for conducting water quality monitoring; for most sites this person is also the Certified Erosion and Sediment Control Lead. 5.2 Team Members Names and contact information for those identified as members of the pollution prevention team are provided in the following table. Title Name(s) Phone Number Certified Erosion and Sediment Control Lead (CESCL) Lori L Harvey, CES NW, Inc 253.241.2846 Monitoring Personnel CES NW, Inc 253.848-4282 Resident Engineer Cara Visintainer, PE, CES NW, Inc 253-848-4282 Site Foreman/Superintendent/Contact Vladimir Tkach, AVT Services, LLC 253-579-8018 Emergency Owner Contact Vladimir Tkach Stormwater Pollution Prevention Plan 26 Ecology Contact: Permit Administrator Josh Klimek, 360.407.7451 Ecology Contact: Emergency Southwest Regional Office 360.407.6300 Jurisdictional Inspector: Pierce County Sam Knox 253.370.7052 OtherEcology Inspector Jess Eakins 360.407.0246 6.0 Site Inspections and Monitoring Monitoring includes visual inspection, monitoring for water quality parameters of concern and documentation of the inspection and monitoring 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; and,  Stormwater quality monitoring. For convenience, the inspection form and water quality monitoring forms included in this SWPPP include the required information for the site log book. This SWPPP may function as the site log book if desired, or the forms may be separated and included in a separate site log book. However, if separated, the site log book but must be maintained on-site or within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. 6.1 Site Inspection All BMPs will be inspected, maintained, and repaired as needed to assure continued performance of their intended function. The inspector will be a Certified Erosion and Sediment Control Lead (CESCL) per BMP C160. The name and contact information for the CESCL is provided in Section 5 of this SWPPP. Site inspection will occur in all areas disturbed by construction activities and at all stormwater discharge points. Stormwater will be examined for the presence of suspended sediment, turbidity, discoloration, and oily sheen. The site inspector will evaluate and document the effectiveness of the installed BMPs and determine if it is necessary to repair or replace any of the BMPs to improve the quality of stormwater discharges. All maintenance and repairs will be documented in the site log book or forms provided in this document. All new BMPs or design changes will be documented in the SWPPP as soon as possible. Stormwater Pollution Prevention Plan 27 6.1.1 Site Inspection Frequency Site inspections will be conducted at least once a week and within 24 hours following any discharge from the site. For sites with temporary stabilization measures, the site inspection frequency can be reduced to once every month. 6.1.2 Site Inspection Documentation The site inspector will record each site inspection using the site log inspection forms provided in Appendix E. The site inspection log forms may be separated from this SWPPP document, but will be maintained on-site or within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. 6.2 Stormwater Quality Monitoring This site (check all that apply) IS LESS than 1 acre IS GREATER than 1 acre but less than 5 acres IS GREATER than 5 acres DOES discharge to a water body listed as impaired under Section 303(d) of the Clean Water Act. See Appendix C - Impaired Body Conditions 6.2.1 Turbidity Sampling Monitoring methods employed will be either: Turbidity Meter (required for site equal to or greater than 5 acres) Transparency Tube Monitoring requirements for the proposed project will include either turbidity or water transparency sampling to monitor site discharges for water quality compliance with the 2016 Construction Stormwater General Permit (Appendix D). Sampling will be conducted at all discharge points at least once per calendar week. Turbidity or transparency monitoring will follow the analytical methodologies described in Section S4 of the 2016 Construction Stormwater General Permit (Appendix D). The key benchmark values that require action are 25 NTU for turbidity (equivalent to 32 cm transparency) and 250 NTU for turbidity (equivalent to 6 cm transparency). If the 25 NTU benchmark for turbidity (equivalent to 32 cm transparency) is exceeded, the following steps will be conducted: Stormwater Pollution Prevention Plan 28  Ensure all BMPs specified in this SWPPP are installed and functioning as intended.  Assess whether additional BMPs should be implemented, and document revisions to the SWPPP as necessary.  Sample discharge location daily until the analysis results are less than 25 NTU (turbidity) or greater than 32 cm (transparency). If the turbidity is greater than 25 NTU (or transparency is less than 32 cm) but less than 250 NTU (transparency greater than 6 cm) for more than 3 days, additional treatment BMPs will be implemented within 24 hours of the third consecutive sample that exceeded the benchmark value. Additional treatment BMPs to be considered will include, but are not limited to, off-site treatment, infiltration, filtration and chemical treatment. If the 250 NTU benchmark for turbidity (or less than 6 cm transparency) is exceeded at any time, the following steps will be conducted:  Notify Ecology by phone within 24 hours of analysis (see Section 5.0 of this SWPPP for contact information). 1. Continue daily sampling until the turbidity is less than 25 NTU (or transparency is greater than 32 cm). 2. Initiate additional treatment BMPs such as off-site treatment, infiltration, filtration and chemical treatment within 24 hours of the first occurrence of NTUs exceeding 250 3. Implement additional treatment BMPs as soon as possible, but within 7 days of the first occurrence of NTUs exceeding 250. 4. Describe inspection results and remedial actions taken in the site log book and in monthly discharge monitoring reports as described in Section 7.0 of this SWPPP. 6.2.2 pH Sampling Stormwater runoff will be monitored for pH starting on the first day of any activity that includes more than 40 yards of poured or recycled concrete, or after the application of “Engineered Soils” such as, Portland cement treated base, cement kiln dust, or fly ash. This does not include fertilizers. For concrete work, pH monitoring will start the first day concrete is poured and continue until 3 weeks after the last pour. For engineered soils, the pH monitoring period begins when engineered soils are first exposed to precipitation and continue until the area is fully stabilized. Stormwater Pollution Prevention Plan 29 Concrete work WILL NOT exceed 40 cubic yards at any given (this section will not apply) Concrete work WILL exceed 40 cubic yards at any given time Engineered soil WILL BE used at this site Engineered soil WILL NOT BE used at this site (this section will not apply) Stormwater samples will be collected daily from all points of discharge from the site and measured for pH using a calibrated pH meter, pH test kit, or wide range pH indicator paper. If the measured pH is 8.5 greater, the following steps will be conducted: 1. Prevent the high pH water from entering storm drains or surface water. 2. Adjust or neutralize the high pH water if necessary using appropriate technology such as CO2 sparging (liquid or dry ice) 3. Contact Ecology if chemical treatment other than CO2 sparging is planned 6.2.3 Temperature This site WILL discharge to a water body listed on the Clean Water Act Section 303(d) list as impaired for temperature. This site WILL NOT discharge to a water body listed on the Clean Water Act Section 303(d) list as impaired for temperature. Temperature monitoring will be conducted using a calibrated temperature meter. Sampling will be conducted at two locations, one upstream from the site discharge location and one downstream from the sites discharge location. If the temperature is higher upstream the following steps will be conducted: 1. Ensure all BMPs specified in this SWPPP are installed and functioning as intended. 2. Assess whether additional BMPs such as relocation or shading of the sedimentation tank should be implemented and revision to the SWPP are necessary Stormwater Pollution Prevention Plan 30 3. Record and report temperatures in the DMR as described in Section 7.0 of this SWPPP If the downstream temperature readings are greater than 1 degree Fahrenheit higher than the temperatures upstream of the discharge point, the following steps will be conducted: 1. Notify Ecology by phone within 24 hours of analysis 2. Immediately initiate additional treatment BMPs such as providing shade to the temporary sedimentation trap, or relocating the uncovered sedimentation tank to a shaded area. 3. Continue daily sampling until the temperature difference between sample locations until is less than 1 degree 4. Describe inspection results and remedial actions taken in the site log book and in the monthly discharge monitoring report as described in Section 7.0 of this SWPPP 7.0 Reporting and Recordkeeping 7.1 Recordkeeping 7.1.1 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; and,  Stormwater quality monitoring. For convenience, the inspection form and water quality monitoring forms included in this SWPPP include the required information for the site log book. Stormwater Pollution Prevention Plan 31 7.1.2 Records Retention Records of all monitoring information (site log book, inspection reports/checklists, etc.), this Stormwater Pollution Prevention Plan, and any other documentation of compliance with permit requirements will be retained during the life of the construction project and for a minimum of three years following the termination of permit coverage in accordance with permit condition S5.C. 7.1.3 Access to Plans and Records The SWPPP, General Permit, Notice of Authorization letter, and Site Log Book will be retained on site or within reasonable access to the site and will be made immediately available upon request to Ecology or the local jurisdiction. A copy of this SWPPP will be provided to Ecology within 14 days of receipt of a written request for the SWPPP from Ecology. Any other information requested by Ecology will be submitted within a reasonable time. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with permit condition S5.G. 7.1.4 Updating the SWPPP In accordance with Conditions S3, S4.B, and S9.B.3 of the General Permit, this SWPPP will be modified if the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site or there has been a change in design, construction, operation, or maintenance at the site that has a significant effect on the discharge, or potential for discharge, of pollutants to the waters of the State. The SWPPP will be modified within seven days of determination based on inspection(s) that additional or modified BMPs are necessary to correct problems identified, and an updated timeline for BMP implementation will be prepared. 7.2 Reporting 7.2.1 Discharge Monitoring Reports Discharge Monitoring Reports (DMRs) will be submitted to Ecology monthly electronically via Ecology’s online Web Portal and will include water quality sampling results for turbidity and pH. If there was no discharge during a given monitoring period, the Permittee shall submit the form as required, with the words “No discharge” entered in the place of monitoring results. The DMR due date is 15 days following the end of each month. 7.2.2 Notification of Noncompliance If any of the terms and conditions of the permit is not met, and it causes a threat to human health or the environment, the following steps will be taken in accordance with permit section S5.F: Stormwater Pollution Prevention Plan 32 1. Ecology will be immediately notified of the failure to comply. 2. Immediate action will be taken to control the noncompliance issue and to correct the problem. 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. Any time turbidity sampling indicates turbidity is 250 NTU or greater or water transparency is 6 centimeters or less, the Ecology regional office will be notified by phone within 24 hours of analysis as required by permit conditions S5.A In accordance with permit conditions S4.F.6.b, the Ecology regional office will be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH water. 7.2.3 Permit Application and Changes In accordance with permit condition S2.A, a complete application form will be submitted to Ecology and the appropriate local jurisdiction (if applicable) to be covered by the General Permit. Stormwater Pollution Prevention Plan 33 Appendix A – Site Plans Stormwater Pollution Prevention Plan 34 Appendix B - Spill Prevention, Control, and Countermeasure (SPCC) Plan Stormwater Pollution Prevention Plan 35 Appendix C – Environmental Constraints and Impaired Body Conditions Stormwater Pollution Prevention Plan 36 Appendix D – General Permit Stormwater Pollution Prevention Plan 37 Appendix E – Site Inspection Forms (and Site Log) The results of each inspection shall be summarized in an inspection report or checklist that is entered into or attached to the site log book. It is suggested that the inspection report or checklist be included in this appendix to keep monitoring and inspection information in one document, but this is optional. However, it is mandatory that this SWPPP and the site inspection forms be kept onsite at all times during construction, and that inspections be performed and documented as outlined below. At a minimum, each inspection report or checklist shall include: a. Inspection date/times b. Weather information: general conditions during inspection, approximate amount of precipitation since the last inspection, and approximate amount of precipitation within the last 24 hours. c. A summary or list of all BMPs that have been implemented, including observations of all erosion/sediment control structures or practices. d. The following shall be noted: i. locations of BMPs inspected, ii. locations of BMPs that need maintenance, iii. the reason maintenance is needed, iv. locations of BMPs that failed to operate as designed or intended, and v. locations where additional or different BMPs are needed and the reason(s) why. e. A description of stormwater discharged from the site. The presence of suspended sediment, turbid water, discoloration, and/or oil sheen shall be noted, as applicable. f. A description of any water quality monitoring performed during inspection, and the results of that monitoring. g. General comments and notes, including a brief description of any BMP repairs, maintenance or installations made as a result of the inspection. h. A statement that, in the judgment of the person conducting the site inspection, the site is either in compliance or out of compliance with the terms and conditions of the SWPPP and the NPDES permit. If the site inspection indicates that the site is out of compliance, the inspection report shall include a summary of the Stormwater Pollution Prevention Plan 38 remedial actions required to bring the site back into compliance, as well as a schedule of implementation. i. Name, title, and signature of person conducting the site inspection; and the following statement: “I certify under penalty of law that this report is true, accurate, and complete, to the best of my knowledge and belief”. When the site inspection indicates that the site is not in compliance with any terms and conditions of the NPDES permit, the Permittee shall take immediate action(s) to: stop, contain, and clean up the unauthorized discharges, or otherwise stop the noncompliance; correct the problem(s); implement appropriate Best Management Practices (BMPs), and/or conduct maintenance of existing BMPs; and achieve compliance with all applicable standards and permit conditions. In addition, if the noncompliance causes a threat to human health or the environment, the Permittee shall comply with the Noncompliance Notification requirements in Special Condition S5.F of the permit. Stormwater Pollution Prevention Plan 39 Appendix F – Reports and Engineering Calculations Stormwater Pollution Prevention Plan 40 Appendix G – Best Management Practices (BMPs)