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I I I I I I I I I I I I I I I I I I I V I. ~.MDIMG_~.D_DBAlMlG.E A Stormwater Management PI an I s bel ng prepared as part of the requl red grading and drainage plan. The college Is applying for a permit fran the RIce Creek Watershed DIstrIct under whIch a detaIled plan and computer model show Ing all elevations, pIpe desIgn, pond sizes and runoff rates w I II be shown. The Stormwater Ma nagement PI an Is expected to be approved prior to PUD acceptance. The enclosed Grading and DraInage Plan, ExhIbIt F, addresses Information Included In the Stormwater Management Plan, and descrIbes al I gradIng and drainage Improvements to the existing facilitIes. The majorIty of the area of the college In Rosev" Ie draIns to the existing pond located just west of the existing residence hal Is. Observations of exIstIng conditions at the pond show the OHW (ordinary high water) to be approximately ElevatIon 902.5. Historic water level s between storms tends to be close to Elevation 901. SInce the current pond outlet Is set at 905.6, It shows this area to have a high Inf Iltratlon rate. Observations by college personnel IndIcate that the elevatIon of the pond only Infrequently reaches the outlet elevation. The existing outlet structure Is designed to skim oils and floatable materials as required by the Rice Creek Watershed District. The fol lowing Is a list of proposed Improvements to the exIsting campus plan and the draInage modifications needed to meet requirements of the RIce Creek Watershed District. 1 ) 1I.mLP~.rJsIDg_I..Q!~_A_LB New Parking Lots A & B are proposed to drain Into the existing pond. Exl stl ng contours show the parkl ng lots natural I y dral n toward the pond. Some pondlng and/or drainage swales or culverts wll I be used In the parking lots to Improve drainage to the pond. 2 . PSI.rJsIDg_J...o!~_.c_'&_Q New Parking Lots C and D are proposed to be designed to provide control led pondlng and runoff on the lots themselves. AI I new roads and parking lots are to be constructed with curb and gutter to al low better drainage control. Addltlona~ pondlng and erosion control w III be prov I ded as necessary to control the runoff to RIce Creek and Little Johanna. 3. 1I~_~~1~eD~e_H~1_RD~_lli~_~D~_He91!b_fl!De~~_~D!~.r An exl stl ng low area adjacent to the proposed LIfe and Heal th Fitness Center, which currently does not normally have sTandIng water, will be developed to provide storage and detentIon for runoff from the LIfe and Health Fitness Center and the proposed new resIdence hall. LImIted roof pondlng will be provIded on both bu II dIngs. -12- 8621