3003 W CASINO RD BLDG 45-12 2016-10-20

2.1.8 Element 8: Stabilize Channels and Outlets Describe how you will prevent downstream erosion'where site runoff is to be conveyed in channels, discharged to a stream or, discharged to a natural drainage point. West of the Cascade Mountains Crest On-site conveyance channels must handle the peak 10-minute flow rate from a Type 1A, 10- year, 24-hour frequency storm for the developed condition. Alternatively, the 10-year, 1-hour flow rate predicted by an approved continuous runoff model, increased by a factor of 1.6, may be used. The hydrologic analysis must use the existing land cover condition for predicting flow rates from tributary areas outside the project limits. For tributary areas on the project site, the analysis must use the temporary or permanent project land cover condition, whichever will produce the highest flow rates. If using the WWHM to predict flows, bare soil areas should be modeled as "landscaped area". East of the Cascade Mountain Crest On-site conveyance channels must handle the expected peak flow velocity from a 6-month, 3- hour storm from the developed condition, referred to as the short duration storm. Provide stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes, and downstream reaches, will be installed at the outlets of all conveyance systems. List and describe BMPs: This project does not anticipate any conveyance channels. Stormwater will be kept out of the jurisdictional ditch and the existing pond at the south west corner of the site. Water leaving the site will be directed towards existing engineered structures. No additional outlet protection is envisioned for these outfalls at this time. Installation Schedules: N/A Inspection and Maintenance plan: N/A Responsible Staff: Steve Roetemeyer with MidMountain Contractors will be the onsite CESCL to maintain. Page 120