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s~ <br />The plan for protection and control of drainage and sediment as described in Section 2.05.6 provides that surface <br />drainage from the disturbed area within the permit area will passed through sedimentation control structures. All <br />ponds will be constructed and maintained to safely contain the volume of a 10-year, 24-hour precipitation event. The <br />quality of water and accumulation of sediment in the ponds will be monitored periodically. In addition, grab samples <br />of water will be collected from the pond and their discharge measured to determine their effectiveness in meeting the <br />applicable Colorado Water quality standards. <br />Discharge from the mining azea, after treatment in sedimentation ponds, is not anticipated to exceed the effluent <br />(imitation of Colorado agency requirements. Baseline ground water quality is discussed in Section 2.04.7, Hydrology <br />Information. <br />4.05.3 DIVERSIONS AND CONVF_ YANCE OF OVERLAND FLOW AND SHALLOW GROI iNDWATER <br />FLOW. AND EPHEMERA TRF MS DRAiNiNG A WATERSHED I..C THAN O O~IARE MILE <br />The drainage and sediment control plan described under Section 2.05.6 provides for temporary diversion of surface <br />drainages within the permit area. A system of temporary ditches, as shown on the Drainage and Sediment Control <br />Plan Map (Map 26), will collect and route runoff within and around disturbed areas. Specifications for all temporary <br />diversions within the permit area are presented in Exhibit 18, Drainage and Sediment Control Plan. <br />The temporary diversions will have the purpose of reducing contribution of suspended solids to runoff and diverting <br />undisturbed drainage from the mine area. The diversions will be constructed with a minimum gradient to pass the <br />design flow and will be revegetated with grasses. Upon completion of mining and at the appropriate point mandated <br />in the Coal Regulations of the Colorado Mined Land Reclamation Board, the temporary diversions will be reclaimed <br />as required in Section 4.05.3(5). <br />None of the diversions will drain surface runoff into underground mines. <br />There will be no stream channel diversions at CEC. <br />4 <br />Sediment control measures to be implemented are shown on the Drainage and Sediment Control Plan Map (Map 26). <br />These facilities, consisting primarily of diversion ditches and sedimentation ponds, are located, constructed, and <br />maintained to minimize erosion and increased contribution of sediment load to runoff. Discussion of the drainage and <br />sediment control is presented under Sections 2.05.3 and 2.05.6. The design parameters and calculations for the <br />sedimentation control structures are found in Exhibit ] 8, Drainage and Sediment Control Plan. <br />As necessary, facilities to control sediment will be installed in areas above or below the planned sites of disturbance. <br />"Upstream" facilities, such as temporary diversion ditches and check-dams upslope from the mining activities will <br />divert runoff away from the disturbed areas or divert the runoff into sediment ponds. <br />4.05.6 SEDIMENTATION PONDS <br />• The location of all sedimentation ponds, is shown on the Drainage and Sediment Control Map (Map 26). The <br />designed plans and specifications for the sedimentation ponds are presented in Exhibit ]8, Drainage and Sediment <br />Control Plan. All sedimentation ponds are located as close as practical to the areas to be disturbed. Other methods of <br />sediment control will be located on the areas to be disturbed. These methods include the use of contour furrowing or <br />terraces. <br />Permit Renewal No. 3 4.01-4 7/15/98 <br />