Laserfiche WebLink
<br />. <br /> <br />MEMORANDUM <br /> <br />DATE: December 3rd, 2002 <br /> <br />TO: File <br /> <br />FROM: Adam Parker, EIT, MFRA <br /> <br />SUBJECT: Gonyea - Centerville, MN <br />MFRA file # 14006 <br /> <br />To meet Rice Creek Watershed District requirements a stormwater analysis was <br />completed as part of the Gonyea project in Centerville, MN. .The stormwater analysis <br />utilized the HydroCAD computer model to determine water quality, and the 1 -year and <br />1 OO-year rainfall event for both existing and proposed conditions. Also included are the <br />effective pervious area and the infiltration worksheet summaries. <br /> <br />WATER QUALITY <br /> <br />Ponds land 2 both provide the water quality treatment for the site. The required amount <br />of storage the pond must have is the equivalent to the runoff volume generated from a 2.5 <br />inch rainfall event (NURP storage). The following table shows the volume of runoff <br />generated from a 2.5 inch stonn for both drainage areas, and the storage provided for <br />both ponds. <br /> <br />Table 1 - Volume provided by both ponds for 2.5 inch rainfall event: <br /> <br />Pond Drainage Area Pond Storage <br /> Volume Provided <br />Pond 1 {lP)* 0.20 acre-feet (18)* 0.35 acre-feet <br />Pond 2 (2P)* 0.25 acre-feet (28)* 0.70 acre-feet <br /> <br />*= node ID's for the HydroCad model and for the proposed drainage map <br /> <br />Appendix A contains the HydroCADmodel results for the NURP event. <br /> <br />L___u <br /> <br />~ <br />