2008-12-04_PERMIT FILE - C1994082A (14)

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Diversion Ditches The diversion ditches or collection drains in the permit area are the following: I D Name Location Design (Tab 13) Ditch No. 1 Facilities Attachment 13-2 Ditch No. 2 Pond 010 Attachment 13-2 Ditch No. 13A Pond 013 Attachment 13-12 Ditch No. 14A Pond 014 Attachment 13-12 Ditches will be used to transport runoff into sedimentation ponds for treatment in accordance with the requirements of applicable regulations and divert surface runoff away from topsoil stockpiles and active mining areas. The locations of the ditches are shown on Exhibit 13-2, Surface Water Control Map (Ditch No. 1 and No. 2) and Exhibit 13-12.1, Yoast Mine Watershed (Ditch No. 13A and No. 14A). The design information for Ditch No.1 and No. 2 is presented in Attachment 13-2, Diversions (Ditch No. 1 was never constructed), while the designs for Ditch No. 13A and No. 14A are included in the pond design demonstrations for Pond 013 and 014, respectively, and are found in Attachment 13-12, Drainage and Sediment Control Plan. Each ditch has been designed and will be constructed in accordance with the applicable regulations in 4.05.3. Diversions will be designed, constructed, and maintained in a manner which prevents additional contributions of suspended solids to streamflow and to runoff outside the permit area, to the extent possible, using the best technology currently available. Appropriate sediment control measures for these diversions may include, but not be limited to, maintenance of appropriate gradients, channel lining, revegetation, roughness structures, and detention basins. No diversion will be located so as to increase the potential for landslides. When no longer needed, each temporary diversion will be removed and the affected land regraded, topsoiled, and revegetated in accordance with 4.06, 4.14, and 4.15. If the temporary diversion was for an ephemeral stream, the channel will be reestablished to functionally blend with the undisturbed drainage above and below the area to be reclaimed. Diversion design will incorporate the following: (a) Channel linings, including channel riprap, will be designed using standard engineering practices to pass safely the design velocities. (b) Freeboard will be no less than 0.3 feet. Protection will be provided for transition of flows and for critical areas such as swales and curves when excessive velocities are anticipated. (c) Energy dissipators will be installed when necessary at discharge points, where diversions intersect with natural streams and exit velocity of the diversion flow is greater than that of the receiving stream. TR-37 3 Revised 02/08