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Biological and Floodplain Assessment, March 16, 2017, by HartCrowser <br /> This document assesses the potential for impacts to endangered species and to the Snohomish River floodplain. <br /> Geotechnical Report <br /> This document documents soil explorations and provides geotechnical recommendations. It is currently in <br /> progress and will be submitted once available. <br /> 7. Other Permits <br /> As the project will be disturbing over one acre of land, a National Pollutant Discharge Elimination System <br /> (NPDES) is required. The NPDES Permit will be held and maintained by the contractor. <br /> The work within 200 feet of the Snohomish River will be exempt from a Shoreline permit as the slip lining <br /> and/or upgrade of the of the existing eight-inch storm pipe and/or outfall is considered a maintenance activity. <br /> An exemption request is currently under review. <br /> 8. Permanent Stormwater Control Plan <br /> A. OFFSITE ANALYSIS <br /> The site discharge location to the existing stormwater system is Stormwater Quality Pond 2. This pond directly <br /> discharges to the Snohomish River via 24-inch storm drain pipes and manholes within one quarter mile <br /> downstream of the pond. There is no known flooding downstream of Stormwater Quality Pond 2. <br /> Currently, the pumped storm drain system in Riverside Road (N-S) does not meet current conveyance <br /> standards as there is no overland flow route for the 100-year return event runoff. Improvements proposed as <br /> part of this project bring the capacity of the downstream system up to current standards. See Conveyance <br /> section 8.F. below for information. <br /> B. PREDEVELOPED HYDROLOGY <br /> The predeveloped condition on the project site is presumed to have been forest land cover on till soils. <br /> Table 8.B: Predeveloped Areas <br /> Land Cover Area <br /> Forested (Till Soil) 4.17 AC <br /> Limit of Work 4.17 AC <br /> See Appendix A for the Predeveloped Hydrology figure showing these areas. <br /> C. DEVELOPED HYDROLOGY <br /> Proposed improvements that modify existing topography and hardscape include Eighth Street construction <br /> and the new sidewalk along Riverside Road (N-S) and Riverside Road (E-W). Riverside Road (N-S) and <br /> KPFF Consulting Engineers <br /> 6 <br />