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Diversion Ditches <br /> <br />The diversion ditches or collection drains in the permit area are the following: <br />I.D. Name Location Design ITab 131 <br /> <br />Ditch No. 1 Facilities Attachment 13-2 <br />Ditch No. 2 Pond 010 Attachment 13-2 <br />Ditch No. 13A Pond 013 Attachment 13-12 <br />Ditch No. 14A Pond 014 Attachment 13-12 <br />• <br />Ditches will be used to transport runoff into sedimentation ponds for treatment in accordance with the <br />requirements of applicable regulations and divert surface runoff away from topsoil stockpiles and <br />active mining areas. The location of each ditch can be found on Exhibit 13-2, Surface Water Control <br />Plan, and Exhibit 13-12.1, Yoast Watershed. The design information can be found in Attachments 13- <br />2, Diversions, and 13-12, Drainage and Sediment Control Plan. <br />Each ditch has been designed and will be constructed in accordance with the applicable regulations in <br />4.05.3. Diversions will be designed, constructed, and maintained In a manner which prevents <br />additional contributions of suspended solids to streamflow and to runoff outside the permit area, to <br />the extent possible, using the best technology currently available. Appropriate sediment control <br />measures for these diversions may include, but not be limited to, maintenance of appropriate <br />gradients, channel lining, revegetation, roughness structures, and detention basins. No diversion will <br />be located so as to increase the potential for landslides. When no longer needed, each temporary <br />diversion will be removed and the affected land regraded, topsoiled, and revegetated in accordance <br />with 4.06, 4.14, and 4.1 5. If the temporary diversion was for an ephemeral stream, the channel will <br />be reestablished to functionally blend with the undisturbed drainage above and below the area to be <br />reclaimed. Diversion design will incorporate the following: <br />lal Channel linings, including channel riprap, will be designed using standard engineering <br />practices to pass safely the design velocities. <br />Ibl Freeboard will be no less than 0.3 feet. Protection will be provided for transition of flows <br />and for critical areas such as swales and curves when excessive velocities are anticipated. <br />1c1 Energy dissipators will be installed when necessary at discharge points, where diversions <br />intersect with natural streams and exit velocity of the diversion flow is greater than that of <br />the receiving stream. <br />• <br />3 <br />Revised 2/99 <br />