1502 WALL ST IMAGINE CHILDRENS MUSEUM 2022-08-25

Element 8: Stabilize Channels and Outlets (2.1 .8) 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". 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. No BMPs are applicable for this project. Installation Schedules: [Insert text here] Inspection and Maintenance plan: [Insert text here] Responsible Staff: [Insert text here]