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REVISED <br />7/30/85 <br />installed and compacted in lifts of 3 feet or less. Following <br />construction of the embankment, the outlet works and tributary diversion <br />ditches were installed. Engineering control during construction <br />consisted of inspection, surveying and compaction -testing of fill <br />material at the direction of a qualified registered professional <br />engineer. The design of Sediment Pond E is shown on the Fish Creek <br />Tipple Sedimentation Pond E As Built Plan View Map (Map Ex 8-1), Ditch <br />and Dam Profiles Map (Map Ex 8-2), and Figure 3, Typical Cross Section <br />of Emergency Spillway. <br />Diversion Ditches <br />Diversion ditches which direct runoff to sedimentation ponds are <br />designed to carry the peak discharge of the 10 -year, 24-hour event. <br />Ditches used to divert undisturbed drainage are desioned for the <br />25 -year, 24-hour event. Design parameters are given in Table 5, Fish <br />Creek Tipple Diversion Ditch Design Specifications; Figure 4, Typical <br />Diversion Ditch Section; Ditch and Dam Profiles Map (Map Ex -8-2); and <br />Ditch Profiles Map (Map Ex 8-3). The ditches are triangular or <br />trapezoidal in shape, with side slopes of 2:1. The Manning flow <br />equation was used to determine the depth of water at the design flow <br />rate. In all cases, ditches are designed with a flow velocity less than. <br />5.0 feet per second, to prevent erosion of the channel.- Lining of <br />earth, vegetation, aggregate or riprap is provided as appropriate. <br />Freeboard of at least 1.0 feet has been provided in all ditches, which <br />is conservative in consideration of Rule 4.05.3, but necessary to <br />prevent breeching of ditches on steep slopes. Topsoil is used in berms <br />of the ditches, and will be used to reclaim the diversions when no <br />longer needed. Survey control of gradients and slopes was utilized <br />during construction. <br />Culverts <br />All culverts are designed to safely pass the 10 -year, 24-hour runoff <br />event, without developing a head of water on the pipe entrance. Inlet <br />control is assumed for all the culvert designs. Flow capacities were <br />-5- <br />