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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />V. IMPACTS ON THE PHYSICAL ENVIRONMENT <br /> <br />A. QUANTITY <br />OF RUNOFF <br /> <br />I <br />I <br /> <br />The quantity of runoff increase generated by the <br />proposed action has been studied for 5 year and <br />100 year frequency storms by the proposer's con- <br />sultant, Glanton Engineering. Using the Rice Creek <br />Watershed District's criteria, detailed computa- <br />tions which indicate acceptable rates of discharge <br />have been developed. <br /> <br />Three ponds are proposed as shown on Figure 10 <br />which will occupy .86 acres and store 1.7 acre feet <br />of storm water. When the water in the ponds is two <br />feet deep, theoretically in the eleventh hour of a <br />100 year storm, the site will be discharging at <br />the rate of 5.2 cubic feet per second. It is pro- <br />posed that the three ponds will be controlled by <br />two submerged weirs which will discharge 1.6 and <br />3.6 cfs respectively to the outlet pipe, a IS" CMP <br />under Windsor Lane. Either piping or open ditch <br />is then proposed to extend southward to where flow <br />would be discharged, via an existing 24 x 30 inch <br />corrugated metal pipe (CMP) under Silver Lake Road, <br />to Silver Lake. <br /> <br />Whereas all this data is very difficult to relate <br />to proposed changes, some approximation of storm <br />water runoff from the site can be presented. Those <br />figures are: <br /> <br />V-I <br />