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14. The and will need a dewaterin device. It is believed that the <br />• existing cu vert will dewater t e pond much too rapid y to serve as <br />a dewaterino device. The pond should be dewatered in 24 to 46 <br />hours. <br />RESPONSE: <br />The principal spillway of the sediment pond serves as the principal <br />dewatering device. The operation of the principal spillway, due to its <br />placement at the design sediment level, allows dewatering when required <br />after a precipitation event. The principal spillway will remain closed <br />during all precipitation events. After water has collected in the <br />sediment pond above the elevation of the principal spillway and allowed <br />solids to settle, the slag gate will be open permit drainage of the <br />excess water from the sediment pond. Holding time of 24 to 46 hours <br />will be possible depending on the necessary settling time required to <br />remove suspended solids from the runoff. <br />15. It is not clear from the desi n whether the and is ex~ <br />• em an a or a portion o of is s ou e c ari ie . <br />RESPONSE: <br />The sediment pond has been both embanked and excavated to provide <br />sufficient volume for sediment storage and holding of runoff from a <br />10-year, 24-hour precipitation event. The embankment as shown has been <br />placed on existing in-place material and the fill material for the <br />embankment been excavated from the upstream portion of the pond. <br />Therefore, the volume utilized the sediment pond is approximately <br />one-half excavated from existing material and one-half results from the <br />embankment. <br />16. How are the flows channeled into the emeraencv saillwav? As shown <br />on Figure 1, the spillway is approximately 20 feet from the top of <br />the embankment and it is not clear from the drawing how water will <br />cross this 20 feet. <br />RESPONSE: <br />• As previously shown on the sediment pond planned view when the water <br />surface in the embankment reaches elevation 7,057, it overflows directly <br />-44- <br /> <br />