8102 EVERGREEN WAY EVERETT 4 CORNERS 2025-08-06

Four Corners Short Plat Stormwater Site Plan Silt fences will be placed as shown on the plans or as directed by the City inspector. In addition, sediment will be removed from paved areas in 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 wash off sediments from adjacent streets in runoff. Whenever possible, sediment laden water shall be discharged into on -site, relatively level, vegetated areas. 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 vaults or detention tanks) can be used during the construction phase. 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: • BMP C121: Mulching • BMP C125: Topsoiling • BMP C140: Dust Control 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. 6. Protect Slopes All cut and fill slopes will be designed, constructed, and protected in a manner than minimizes erosion. The following specific BMPs will be used to protect slopes for this project: • BMP C120: Temporary and Permanent Seeding • BMP C207: Check Dams Minimal construction is proposed for wet weather season and slope protection can be established with final landscaping. 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. 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: • BMP C220: Storm Drain Inlet Protection 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: • BMP C209: Outlet Protection 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 1 A, 10-year, 24-hour CPH Project No. 0024-18-042 CPIH CONSULTANTS October 23, 2020 Page 7