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Revised August 12, 1981 <br />OUTLET WORKS <br />Primary Outlet Works <br />A riser was designed for the ponds to achieve a 24-hour <br />theoretical detention time which is necessary to achieve the <br />required effluent level. The risers will be constructed of <br />corrugated metal pipe (CMP) and will have only one hole whose <br />size and elevation vary for each pond, and are tabulated on <br />the Pond Schedule (Plate ar,1 ). Plate a7 shows typical discharge <br />rating curves for depths up to the top of the riser. Plate~?~ <br />entitled Principle Spillway Rating Curve, shows an example of <br />the discharge rating curve for the primary outlet for depths <br />above the riser top. The top of the risers were set at 0.1 <br />foot above the 10-year flood elevations, with the holes set <br />at the 100 percent sediment volume level. The primary <br />spillway outlet for Ponds A, B and C will be directed toward <br />Mann Draw. The outflow from Pond H will enter Ditch C1, which <br />flows into Pond C. <br />Emergency Spillways <br />In accordance with Rule 4.05.6(3-d) of the CMLRB, the <br />25-year, 24-hour precipitation event was used to size the <br />emergency spillway for each pond. The 25-year storm was <br />utilized since none of the ponds exceeded the CMLRB 10-foot <br />height or the 1,000 acre-foot storage volume, or the 20-acre <br />surface area criteria. In addition, for all the ponds, a weir <br />type overflow was used (Q = CLH1.5) <br /> <br />~C1 Leonard Rice Consulting Water Engineers.lnc. <br />`~/ <br />