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4 <br /> <br />Development of the 4.503 acres site includes 1.98 acres of hardscape (44%) and 2.52 <br />acres of pervious surface (56%). For the R-4 zoning district, impervious surface shall not <br />exceed 65%. The site as proposed is in compliance with the impervious surface <br />requirement. <br /> <br />Existing Conditions <br /> <br />Per the stormwater management plan, the site was partially graded as part of the mass <br />grading for the NorthPointe master plan of development. At that time, two wet <br />sedimentation basins were constructed to provide rate control and water quality treatment <br />for the proposed site. <br /> <br />Proposed Conditions <br /> <br />Stormwater for the proposed conditions will mostly flow to the existing wet <br />sedimentation ponds 200P and 300P. These ponds will overflow to Wetland 1P, which <br />outlets to Ditch 3P. Ultimately, all stormwater outlets to Ditch 3P. An outlet control <br />structure will be constructed for Pond 300P as part of this project. <br /> <br />No impacts are proposed to the wetland in the south. <br /> <br /> <br /> <br />The rates for Pond 200P include increases from the rates included in the Master Plan for <br />the NorthPointe Development, and decreases for Pond 300P. All water ultimately flows <br />to Ditch 3P, which did see a slight increase for the 10-year storm event and decreases for <br />the 2- and 100-year storm events from the calculations included in the Master Plan. The <br />stormwater management plan notes that this increase is not significant enough to affect <br />downstream conveyances. <br />