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3 <br /> <br />The project site is within a mile of, and drains to, Marshan Lake, which is an impaired <br />water. This will impact timelines on soil stabilization and should be noted in the <br />Stormwater Pollution Prevention Plan. <br /> <br /> <br />Soils <br /> <br />The Natural Resource Conservation Service Web Soil Survey notes the following soil <br />types on the project site: <br /> <br />Zimmerman fine sand on 0-6 % slopes. This is a hydrologic group A soil that is <br />excessively drained with rapid permeability and negligible to low surface runoff. <br /> <br />Soderville fine sand on 0-3 % slopes. Also a hydrologic group A soil that is moderately <br />well drained. Permeability is rapid to moderately rapid with negligible runoff. <br /> <br />Per the Design Phase Geotechnical Exploration Report, seven soil borings were <br />performed to depths of about 15 feet. The borings encountered 1.5 feet of topsoil over <br />dark sand and clean brown sand. Groundwater was not encountered in the borings. <br /> <br />One of the borings was completed in the proposed location of the north infiltration basin. <br />This boring encountered poorly graded sands, which have high infiltration rates. <br /> <br /> <br />Stormwater Management <br /> <br />A stormwater management plan has been submitted and is being reviewed by the City <br />Engineer. The following summary review is based upon the Stormwater Management <br />Report. <br /> <br />Existing Conditions <br /> <br />Per the Stormwater Management Plan, the site is currently well vegetated, with all runoff <br />draining to a stormwater pond located at the northwest corner of Apollo Drive and Lilac <br />Street. <br /> <br />Proposed Conditions <br /> <br />Under the proposed conditions, there will be 1.02 acres of new impervious surface. Two <br />infiltration basins will be constructed at the north and south portions of the childcare <br />facility site. These basins will accommodate volume for the existing project and a <br />portion of the volume that would be generated by future development on the parcel to the <br />west. Future development on this second parcel will potentially require an additional <br />infiltration basin. <br /> <br />The runoff rates for the site will be lower for all discharge locations and all storm events.