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1. INTRODUGTION <br /> The Eisinger Meadow Residential development is proposed to be located on a 30.5 acre parcei <br /> between Wayzata Blvd.and US Hwy 212 in Orona, MN. The development will inciude a 28' <br /> roadway to access 27 new graded single-family lots,with curb and sewer for stormwater <br /> conveyance. A stormwater treatment and rate control area will be constructed, and wetland <br /> buffer regions will be established meeting Watershed District requirements. <br /> The disturbed area is approximately 7.0 acres, and will include the addition of 2.2 acres of new <br /> impervious coverage. This level of construction activity must typically meet the requirements <br /> of the City,the Minnehaha Creek Watershed District (MCWD) and the MPCA. However, since <br /> the project will increase the impervious area of the property by le5s than 20%,the project is <br /> exempt from the MCWD Stormwater Management Rule. This report summarizes the design <br /> caltulations completed to meet City and MPCA requirements;storm sewer design is completed <br /> by others. <br /> The specific requirements addressed are as follows: <br /> MPCA Requirements: <br /> 1) Infiltrate or fiiter the Water Quality Volume (W4V) of 1.0" of runoff from the newly <br /> created impervious areas. Three feet of separation required between bottom of basin <br /> and seasanal high water table. Alternative treatment permitted if necessary. <br /> 2) Provide pretreatment for filtration/infiltration areas. <br /> 3) Insta{I skimming device to �emove buoyant material {oil,grease,trash,etc.) prior to <br /> discharge downstream. <br /> 4) If applicable,wet ponds designed for treatment of the WQV shall include a dead-pool <br /> storage voiume equ�l to 1,800 CF per acre draining to the pond. In addition,the WQV <br /> shall be restricted to a discharge rate of 5.66 cfs per acre of pond surface <br /> Cltv of Orono Reauirements: <br /> 1} Rate control: Existing flow rates must be maintained far the 2-year(2.9"�, 10-year(4.2") <br /> and 100-year{7.3") rainfall events. <br /> 2) Treatment requirements per MPCA& MCWD. <br /> Z. EXISTING SITE DESCRIPTION <br /> The existing parcel consists of undeveloped land cantaining a single dwelling and grass, shrubs, <br /> trees,and wetlands. The soils prese�t at the upland areas of the site are primarily Angus and <br /> Eisinger Meadow-SWMP Page � 1 <br /> March 2016 <br />