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Stormwater Pollution Prevention Plan
For La Fortuna Phase 3Prepared For Habitat for Humanity Seattle-King County560 Naches Ave. SW Suite 110Renton, WA 98057Owner Habitat for Humanity Seattle-King County Developer Habitat for Humanity Seattle-King County Operator/Contractor Orozco Excavating INCProject Site Location 17xxx 127th A venue SE Renton, Washington Certified Erosion and Sediment Control Lead Cameron O’NeillEnvironmental Scientist Cell: (425) 213-3161
SWPPP Prepared By Nolan CorlettHabitat for Humanity Seattle-King County
560 Naches Ave. SW Suite 110
Renton, WA 98057
SWPPP Preparation Date June 15, 2020 Approximate Project Construction Dates June 2020 through June 2021 n
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Contents
1.0 Introduction ............................................................................................................................... 1
2.0 Site Description ........................................................................................................................ 3
2.1 Existing Conditions ........................................................................................................... 3 2.2 Proposed Construction Activities ...................................................................................... 3
3.0 Construction Storm water BMPs ............................................................................................... 5
3.1 The 12 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 .......................................................... 6
3.1.5 Element #5 -Stabilize Soils ............................................................................ 6 3.1.6 Element #6-Protect Slopes ............................................................................ 7 3.1.7 Element #7 -Protect Drain Inlets .................................................................... 7
3.1.8 Element #8 -Stabilize Channels and Outlets .................................................. 7
3.1.9 Element #9 -Control Pollutants ...................................................................... 7 3.1.10 Element #10-Control Dewatering ................................................................. 7
3.1.11 Element #11 -Maintain BMPs ........................................................................ 9 3 .1.12 Element # 12 -Manage the Project.. ................................................................ 9 3.2 Site Specific BMPs ............................................................................................................ 8
3.3 Additional Advanced BMPs .............................................................................................. 8
4.0 Construction Phasing and BMP Implementation ..................................................................... 8
5 .0 Pollution Prevention Team ...................................................................................................... 11
5 .1 Roles and Responsibilities ............................................................................................... 11 5 .2 Team Members ................................................................................................................ 12
6.0 Site Inspections and Monitoring ............................................................................................. 13
6.1 Site Inspection ................................................................................................................. 13 6.1.1 Site Inspection Frequency .............................................................................. 13
6.1.2 Site Inspection Documentation ...................................................................... 14 6.2 Storm water Quality Monitoring ...................................................................................... 14
6.2.1 Turbidity ........................................................................................................ 17 6.2.2 pH ................................................................................................................... 17
7.0 Reporting and Recordkeeping ................................................................................................ 15
7 .1 Recordkeeping ................................................................................................................. 15
7.1.1 SiteLogBook ................................................................................................ 15 7.1.2 Records Retention .......................................................................................... 15
7.1.3 Access to Plans and Records .......................................................................... 15 11
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1.0 Introduction
This Storm water Pollution Prevention Plan (SWPPP) has been prepared as part of the NPDES stormwater permit requirements for the La Fortuna construction project in Renton, Washington.
The site is located at 12ih Avenue SE. Site work will involve approximately 2.25 acres of ground disturbance to construct 12 new multi-family buildings.
Construction activities will include excavation, grading, installation of underground utilities, foundation construction, home construction, and landscaping. 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 andsedimentation, 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 controllingpeak flow rates and volumes of stormwater runoff at the Permittee'soutfalls and downstream of the outfalls.
This SWPPP was prepared using the Ecology SWPPP Template downloaded from the Ecology
website on June 15, 2020. This SWPPP was prepared based on the requirements set fo1th in the Construction Stormwater General Permit, Stormwater Management Manual for Western
Washington (SWMMWW 2019) and in the Stormwater Management Manual for Eastern Washington (SWMMEW 2019). The 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 summarydescription of the project, and the organization of the SWPPP d<?cument.
Section 2 -SITE DESCRIPTION. This section provides a detaileddescription of the existing site conditions, proposed construction activities,
and calculated stormwater flow rates for existing conditions and postconstruction conditions.
( ■■ Stormwater Pollution Prevention Plan 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 2019). 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 identifiesthe appropriate contact names (emergency and non-emergency),monitoring personnel, and the onsite temporary erosion and sedimentationcontrol inspector■■ Section 6 -INSPECTION AND MONITORING. This section provides adescription of the inspection and monitoring requirements such as theparameters of concern to be monitored, sample locations, samplefrequencies, and sampling methods for all stormwater discharge locationsfrom 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 -Construction BMPs Appendix C -Alternative Construction BMP list Appendix D -General Permit Ap_pendix E -Site Log and Inspection Forms 2
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2.0 Site Description
2.1 Existing Conditions
The proposed site is located at 12?1h Avenue SE in Renton, Washington. A site vicinity map and
coordinates are provided in Appendix A. The area of site disturbance will be approximately 2.25 acres in size. The existing lots will be graded and 8 multi-family buildings will be constructed. The topography of the site and surrounding properties is generally flat to gently sloping.
Surficial soils consist of existing fill soils and Vashon lodgement till sediments. At the time of
construction, we estimate that groundwater table is approximately 15 feet below the ground surface.
Runoff from the site is collected in catch basins on the existing roadway and is conveyed by
pipes to a previously constructed storm water retention vault. The vault discharges to the
adjacent wetland to the southwest of the vault. (Appendix A)
There are no critical areas on the site such as high erosion risk areas, streams, or steep slopes
(potential landslide area). There is a wetland along the west side of the project area.
2.2 Proposed Construction Activities
The proposed development includes the construction of 12 multi-family buildings. The buildings will be constructed on the previously graded lots. New sanitary sewer, water, electrical, and storm drain utilities will need to be extended to service the buildings ..
Construction activities will include site preparation, TESC installation, excavation for the building foundations, poured concrete foundations, and utility installation. The schedule and
phasing of BMPs during construction is provided in Section 4.0. 3
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Stormwater Pollution Prevention Plan
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 particular BMPs specifications (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 upon completion of the project (Approximately June 2021)
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.
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Emphasize erosion control rather than sediment control.
Minimize the extent and duration of the area exposed.
Keep runoff velocities low.
Retain sediment on site.
Thoroughly monitor site and maintain all ESC measures.
Schedule major earthwork during the dry season.
Maintain an updated SWPPP and site log book.
4.0 Construction Phasing and BMP
Implementation
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.
■Mobilize equipment on site:
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( ■■■■■■■Stormwater Pollution Prevention Plan Mobilize and store all ESC and soil stabilization products: Install ESC measures (silt fence): Install stabilized construction entrance: Begin clearing and grubbing: Excavation for building foundations Begin concrete pour and implement BMP C 151: Project completion/TESC BMP removal: 9 6/23/2020 6/23/2020 6/23/2020 6/23/2020 7/13/2020 8/3/20206/18/2020
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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) Cameron O'Neill 425-213-3161
Resident Engineer
Emergency Ecology Contact
Emergency Owner Contact Nolan Corlett 425-591-8386
Non-Emergency Ecology Contact Nolan Corlett 425-591-8386
Monitoring Personnel Cameron O'Neill 425-213-316112