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19 <br />The Operator has three sediment ponds, which collect surface disturbance runoff <br />from the East Portal area. These ponds are 004, 007 and 008. A fourth pond, pond <br />005, was reclaimed in 2003, as the area serviced by this pond was never used for <br />mining related activities. These sedimentation ponds and associated diversion ditches <br />have been designed according to Section 4.05.6 of the DRMS Regulations. In <br />addition, the diversion structures have been designed utilizing the requirements of <br />4.05.3 and 4.05.4. Typical sections of the emergency spillways and embankments of <br />each sediment control structure are shown in Figure 3, Typical Embankment Cross <br />Section. Typical diversion sections are provided on Map 13 Sediment and Surface <br />Water Control Plan- East Portal. Table 20, Ditch Data, is a summary of the diversion <br />(ditch) data relating to Map 13. Table 21, Culvert Sizing and Figure 23, Culvert <br />Sizing Nomograph, provide backup for culvert sizing as per requested drainage <br />modifications. Table 23, Sediment Pond Dimensions, is a summary of sediment pond <br />dimensions. <br />The Operator will control West Portal drainage using ditches, containment areas and <br />bypass culverts. All structures are shown on Map 14, Sediment and Surface Water <br />Control Plan -West Portal. Calculations are found in Exhibit 19, Sediment Design <br />Specifications. <br />Runoff from the DWDA #3 is routed through a series of diversion ditches and will be <br />routed to Containment Area No. 2. The sedimentation control plan for the DWDA <br />#3 is contained in Exhibit 19(22) and was evaluated based on the 100 -year, 24 -hour <br />event. Runoff from the undisturbed upland areas to the west are diverted around the <br />pile in ditch D49. Runoff from a small - undisturbed upland area east of the pile is <br />routed through the diversion ditches and routed to containment area 2. <br />Ditches 27 and 69 will direct runoff to Containment Area 2. Containment Area 2 has <br />been designed to contain the 25 -year, 24 -hour event, per Rule 4.05.9(2)(e) and as <br />such an emergency spillway system is not required. The total drainage area for <br />Containment Area 2 is 13.14 acres. A total of 1.93 acre -feet of storage is required to <br />handle the 25 -year 24 -hour event. The required water storage volume is 1.84 acre - <br />feet, and the three -year sediment volume is 0.1 acre -feet. <br />Ditch 28 will direct a combination of disturbed and undisturbed runoff to <br />Containment Area 1. A total of 1.51 acre -feet of storage is required to handle a 10- <br />year 24 -hour event and 2.01 acre- feet for a 25 -year 24 -hour event. The three -year <br />sediment storage volume is 0.07 acre -feet. Containment Area 1 also controls drainage <br />from the sediment drying area and the soil storage area associated with the DWDA <br />#3. <br />The sediment drying area will be located where the non -coal waste area was <br />previously permitted. Material excavated from ditches, catchments and sediment <br />ponds will be placed in the sediment drying area and allowed to dry before being <br />hauled to a suitable stockpile. Material from the sediment drying area may be used <br />as plant growth medium. <br />Section 2.05 TR -68 12/10/2014 <br />