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If any of the above mentioned sediment control measures are employed, they will be used inside <br />the primary sediment control systems or in conjunction with small area exemptions (SAE). These <br />measures, if necessary, will also not be implemented on any designed structures (i.e. conveyance <br />ditches or sediment ponds). <br />All surface mining operations will be conducted to achieve the effluent limitations of 4.05.2(7) <br />for all mixed drainage when it leaves the permit area. Sedimentation ponds, diversion ditches, or <br />impoundments will be constructed before creating new disturbances, unless approved drainage <br />diversions or other surface water control structures are installed. <br />C. Collection Ditches, Culverts and Diversion Design Parameters <br />The main collection ditches in the original permit area are the 007 East and 007 West Ditch. <br />These have been renamed Ditches C18 and C17, respectively. These ditches are used to transport <br />runoff into Sedimentation Pond 007 for treatment in accordance with the requirements of <br />applicable regulations. The location and drainage area of these ditches can be found on Map <br />2.05.3(3)-1. All ditch and culvert designs for the entire site have been reviewed for the Mid Term <br />Review of 2006. This review resulted in the redesign of some culverts and ditches, all of which <br />are presented in Attachment 2.05.3(3)-1. As of the Mid Term Review of 2006, there are no <br />surface water control structures of any kind at the New Horizon #1 site. <br />All ditches were designed and 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 stream flow and to runoff outside the permit area, <br />to the extent possible, using the best technology currently available. Appropriate sediment <br />control measures for these diversions may include, but not be limited to, maintenance of <br />appropriate gradients, channel lining, revegetation, roughness structures, and detention basins. <br />No diversion will be located so as to increase the potential for landslides. When no longer <br />needed, each temporary diversion will be removed and the affected land regraded, topsoiled, and <br />revegetated in accordance with 4.06, 4.14, and 4.15. If the temporary diversion was for an <br />ephemeral stream, the channel will be reestablished to functionally blend with the undisturbed <br />drainage above and below the area to be reclaimed. Diversion design will incorporate the <br />following: <br />a. Most ditches will not need to be lined; however, any stretch of collection ditch <br />which has a velocity above 5.5 feet per second will be lined. Channel linings, <br />including channel riprap, will be designed using standard engineering practices to <br />pass safely the design velocities. These velocities assume the typical silty loam <br />soil conditions on site. If better conditions exist, the velocities will be allowed to <br />increase without lining. If worse conditions exist, lining may be needed for lower <br />velocities. <br />Section 2.05.3(3) Page 2 February 2017 (TR -78) <br />