2102 ROSS AVE 2018-01-02 MF Import

V RISK ASSESSMENT RISK ASSESSMENT AND BEST MANAGEMENT PRACTICES Drainage is tributary to Snohomish River. Due to the proximity to this water body, silt -laden runoff could exit the site and enter downstream drainage courses if proper construction practices arc not followed. In order to protect the downstream conditions from sediments, several erosion control Best Management Practices (BMP's) from the DOE manual will be utilized. A temporary gravel construction entrance shall be used between the road and development area, as necessary to knock mud off of tires on vehicles exiting the site. Additionally, limiting earthwork and utility construction activities to dry weather conditions, minimizing area and duration of soil exposure, construction of temporary storage basins and protective dikes to control storm runoff, and stockpiling and sheathing of strippings, will further reduce the potential for silt -laden runoff. Interim measures to be employed during construction will include the construction of sediment basins, the installation of silt fences along the low side of areas to be cleared and graded, and mulching and hydroseeding of exposed soils after attainment of final grade. Stockpiles will be covered with polyethylene sheathing. 1. Factors expected to create an erosion risk when developed: • Exposure of soils during grading. 2. Location relative to critical areas: • none. 3. Soil type: • The surface soils are river dredge spoils. 4. Potential for slides or other ground movement: • None 5. Sources of writer for erosion: • Rainfall G. Measures proposed to minimize and prevent erosion to the greatest extent possible for the decelopntent: • Preparation and implementation of an erosion and sedimentation plan which is sensitive to the soils, slopes, and construction season • Sedimentation trap • Silt fencing • Gravel construction entrance 7. Sources of water for erosion: • Rainfall lDrainage Report Page 5 McClean Ironworks May 8, 2008 Revised July 8, 2008