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2. Drawdown within 48 -hours or 72 -hours from the end of a storm event, for <br />surface or sub -surface features, respectively. Soil infiltration rates shall be based on the <br />appropriate HSG classification and associated infiltration rates (see Table 1 in Appendix <br />A) . Infiltration area will be limited to the horizontal areas subject to prolonged wetting; <br />and <br />3. A minimum of three feet of separation from the seasonal high water table. <br />4. Design and placement in accordance with the Minnesota Department of <br />Health guidance called "Evaluating Proposed Stormwater Infiltration Projects in <br />Vulnerable Wellhead Protection Areas." <br />(b) Permanent sedimentation and water quality ponds must be designed to <br />provide: <br />1. Water quality features consistent with NURP criteria and City wet pond <br />criteria; <br />2. A permanent wet pool with dead storage at least equal to the runoff from a <br />2.5 -inch rainfall over the area tributary to the pond; and <br />3. An outlet structure capable of preventing migration of floating debris and <br />oils for at least the one-year storm. <br />(c) Detention basins must be designed to provide: <br />1. An outlet structure to control the 2 -year & 100 -year frequency events to <br />existing peak runoff sites; and <br />2. An identified overflow spillway sufficiently stabilized to convey flows <br />greater than the 100 -year critical storm event. <br />(d) An outfall structure discharging to a wetland, public water or public water <br />wetland must incorporate a stilling -basin, surge -basin, energy dissipater, placement of <br />ungrouted natural rock riprap or other feature to minimize disturbance and erosion of <br />natural shoreline and bed resulting from stormwater discharges. <br />(e) All new residential, commercial, industrial and other habitable or non - <br />habitable structures, and all stormwater basins, must be constructed so that the lowest <br />floor and lowest entry elevations of structures comply with the following table: <br />Local <br />Detention <br />Regional <br />Basins & <br />Rain- <br />Ground <br />Elevations <br />Wetlands <br />Infiltration Basins <br />gardens <br />Water <br />