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• regulations, will be installed. If a pond is designed to contain the runoff from a 25 year 24 event, an <br />emergency spillway cut into the dam will still be installed. <br />e) Pond freeboard will be a minimum of 1.0 feet from the highest level of water allowed in the <br />pond (or emergency spillway) to the top of dam. <br />f) All pond dams will be designed to have a height of less than 10.0 feet measured from the <br />original ground in the middle of the dam to the top of the dam. The top of dam width will be at least <br />10.0 feet in all areas. <br />G) All ponds will have a keyway cut along the entire width of the dam as shown on Map Att <br />2.05.3(3)8-1. This keyway will be filed with competent material and compacted to the same <br />standards as the dam foundation. <br />H) All principal spillways will have 2 seep collars installed within the dam which will be at least 2x <br />the pipe diameter. All dam fill will be compacted around the seep collars and principal spillway pipe <br />to 90% of the maximum dry density of the fill material. <br />i) The emergency spillways will be a rip-rap lined trapezoidal channel of 10 feet bottom width and <br />• 2:1 sideslopes. <br />The sediment storage capacity of the sedimentation ponds will be monitored and modified as <br />described in the above Sediment Pond 007 subsection. The excavated material handling and <br />inspections is also described in Sediment Pond 007 subsection. <br />Pit dewatering will be primarily a seasonal occurrence. The dewatering process will be a sporadic <br />operation-controlled, occurrence depending on various factors which may include the location of the <br />pit inflows, the location of standing water in the pit, or the location within the pit of the overburden <br />and coal removal operations. When pit dewatering is required, the anticipated dewatering rate will <br />be in the range of one to two cubic feet per second or less. Until Pond 010 is built, all pit <br />dewatering discharges will be directed to Pond 007, which is the main pond for the permit area. <br />However, once Pond 010 is constructed, direct pit pumping into it may occur if conditions warrant. <br />These procedures will be applied for in WFC's NPDES Permit, which will be similar to Permit CO- <br />0000213 for Ponds 007, 008 and 009. Actual water flow velocity going into Pond 010 (when built) <br />2.05.3(3) - 14 <br />• <br />