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• Roads. The ditches were assumed to be stabilized with grass <br />lining;. design velocities were kept under 5-feet per second <br />to prevent erosion and additional contribution of sediment to <br />runoff. The steep reaches at the ends of ditches A-1, I-3 and <br />F-2 will require riprap lining [refer to Energy Mine No. 3 <br />Surface Water Hydrology (Energy Fuels Map 8)]. <br />PONDS <br />The LRCWE Plate I, Sedimentation Ponds, contains a schedule <br />with information describing the six ponds. They range in <br />height from 3.4 to 8.1 feet in height using the height <br />criteria specified in Rule 4.05.10. The ponds range in size <br />from 1.1 to 13.7 acre-feet. <br />Dam crests and embankment slopes of all ponds should be <br />protected with vegetative cover. Side slopes are specified at <br />• 3:1 upstream and 3:1 downstream, and all embankments should <br />be constructed of suitable material which is adequately <br />compacted. Cutoff trenches will be provided. <br />MAINTENANCE PROGRAM <br />Maintenance of sedimentation ponds and diversion ditches will <br />be required during the intended life of the structures. <br />Sediment will be removed from the ponds when it has <br />accumulated to sixty percent of the design sediment storage <br />volume. Pond embankments will be inspected a minimum of four <br />times per year, but after every significant inflow, for <br />structural weakness or erosion, and repairs made when <br />necessary. Rills and gullies deeper than 9 inches which <br />develop on an embankment will be properly backfilled and <br />revegetated. Operating spillways will be inspected regularly <br />• and maintained in a manner to insure proper performance. <br />Leonard Rice Consulting Water Engineers. Inc. <br />