8407 BROADWAY STADIUM STORAGE 2017-06-20

Technical Information Report July 2015 Everett Self-Storage 5.1.3 Element #3— Control Flow Rates In order to protect the properties and waterways downstream of the project site, stormwater discharges from the site are to be controlled. The project site is located in Wood Creek basin - Snohomish River Watershed and therefore the project is required to comply with Minimum Requirement 7 (Ecology 2005). In general, discharge rates of stormwater from the site are to 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. Since this is a re-development project, it is not desirable to disturb additional paved area for constructing a temporary sediment pond. • Temporary Sediment Pond (BMP C241) • Sediment Trap (BMP C240) 5.1.4 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: • Materials on Hand (BMP C150) • Storm Drain Inlet Protection (BMP C220) • Silt Fence (BMP C233) 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 on-site, relatively level vegetated areas (BMP C240 paragraph 5, page 4-102). 5.1.5 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) • Plastic Covering (BMP C123) • Dust Control (BMP C140) The project site is located in Wood Creek Basin — Snohomish River Watershed. 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. 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. 14114 Everett Storage TIR Revised 0715.doe 34