HYDRO29393 - Laserfiche WebLink

Home Browse Search

September 18, 2001 Page 3 of 3 Pages dischazge from a 10-year - 24 hour event. The peak discharge of such an event is demonstrated to be 0.89 cubic feet per second. The peak sediment concentration in the effluent from such an event is demonstrated to be 4,319 milligrams per liter, and the peak settleable concentration is demonstrated to be 0.00 milliliters/milliliter. The design capacity of this pond is 0.96 acre feet of sediment and water prior to initial dischazge. At full design sediment storage of 0.02 acre feet, the pond is designed to hold 0.94 acre feet of water at initial discharge. By reference 2), Colowyo reports that a 1998 design capacity of the Rail Loop Pond is 0.9991 acre feet before dischazging. This is over (by 0.05 acre-feet) the design on file at the Division. This reference also states that there was approximately 5 feet of sediment in the pond at a June 10, 2001 survey. This is 4.17 feet over the design maximum of 0.83 feet, and reduced the design 0.94 acre-feet of (water) storage to 0.47 (a state where there is not capacity of the pond). This reference also indicates that the capacity of the pond under current conditions of the pond (June 14, 2001) was 0.3214 acre feet of water (an elevation of 4.67 feet above the design sediment maximum). This pond has since been cleaned out (reference 6, September 12, 2001). Inspection records of the Division were checked back through November 15, 2000. There was no notation found that would add to the pond capacity information above. Please let me know if I can be of additional assistance. Yours truly, /J Byrdn G. Walker Environmental Protection Specialist CC: Stephen R. Hinkemeyer, Engineering Manager, Colowyo Coal Company, L.P., 5731 State Highway 13, Meeker, CO 81641 Kimberley A. Wolf, Environmental Engineer, Colowyo Coal Company, L.P., 5731 State Highway 13, Meeker, Colorado 81641 Daniel L. Hernandez, CDMG Files: C:\WPDOCS\Colowyo\CDMR Colowyo.doc CDMR, Colowyo, 1s` Quarter 2001