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<br />e <br /> <br />e <br /> <br />.~ <br /> <br />A toe drain is included to control seepage through the embankment. <br />The drain would probably be a sand filter (ASTM C-33 sand) with a <br />slotted drain pipe to convey water out of the filter. The drain is <br />estimated to be 5 feet deep, 2 feet wide and about 500 feet long. <br /> <br />OUTLET PIPE: The outlet pipe size is suggested to be 36 inch <br />diameter which is significantly larger than the size required by <br />the Rules and Regulations but provides easier operation and <br />maintenance and if a liner is needed in 50 years or so, it can be <br />installed without impacting the ability to drain the top 5 feet of <br />the reservoir in 5 days. The pipe material should be thick walled <br />steel, possibly lined with mortar or another material; CMP is not <br />recommended. <br /> <br />SPILLWAY: The spillway will be sized to pass the PMP (probable <br />maximum precipitation) from the approximately 35 square mile <br />drainage area. Using Bureau of Reclamation criteria for estimating <br />design floods for reconnaissance studies, the peak flow would be <br />about 18,000 cfs with about 7000 acre-feet of volume. <br /> <br />A 110 foot wide channel and 15 feet of freeboard would pass about <br />18,000 cfs. The location of the spillway is on the east abutment <br />and is planned to be a channel around the embankment then back to <br />the stream. A concrete control section is included to maintain the <br />channel shape. During the design process alternative spillway <br />locations and configurations should be investigated to attempt to <br />determine the best combination of spillway width and freeboard. <br /> <br />Sams Knob Dam <br /> <br />7 <br />