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• Pond 013 Desinn Details <br />Pond 013 is a partially incised pond designed to contain the Flow from a 25 year 24 hour storm below the emergency spillway. The valve <br />on the principal spillway pipe is normally held shut. The pdncipal spillway design is an 18-24"diameter CMP or other pipe which will have <br />a valve on the entrance. This pipe will be stopped down in the inlet side to a 6" valve which will be controlled by a wheel on the pond <br />embankment. Dudng normal conditions, the valve will be shut to provide 24 hour detention Gme for each pond during the large events. <br />When a large event occurs, the operator will wait a minimum of 36 hours after the stone has ceased to check the water still detained by <br />the pond. If an Imhoff wee shows that the water meets the efFluent standard of O.SmI settleable solids per liter, the valve will be opened <br />until the water has dissipated to the valve level. It will then be shut to allow detention time for subsequent storms. <br />As shown below, the 25 year inflow is 4.11 acre feet. The three year sediment volume is 0.629 acre feet, therefore, the total volume <br />required below the emergency spillway is 4.725 acre feet. As shown on Map 2.05.3(3)-6-1, the emergency spillway bottom for the pond <br />is located at elevation 5569.0'. As shown on the enclosed stage storage relationship, the volume of 4.725 acre feet is found at elevation <br />5568.5', therefore, there is more than enough volume to wntain the 25 year event. For this reason, no routing of the 10 year event or the <br />25 year event is needed. <br /> <br />• asvtsaDtut,vzooe Attachment 2.05.3(3)-6-22 <br />