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• Diversion Channels <br />Diversion and collection ditches for the interim configuration are shown on Figure 2.2-6 <br />and the as-constructed configuration is shown on Figure 2.2-6a. The interim configuration <br />shows the partially reclaimed area with the pond and a portion of the coverFll and topsoil piles <br />remaining in place. Therefore, Ditch M which was located on the coverfill pile as part of the as- <br />constructed is removed as the coverfill pile is partially reclaimed. Diversion and collection <br />ditches for the reclaimed configuration are shown on Figure 2.2-7a. The reclaimed configuration <br />shows the final reclamation configuration with the removal of the pond, the coverfill and topsoil <br />piles. Therefore, Ditches L and K are removed as they were originally located on the topsoil and <br />coverfill piles and are no longer necessary in the reclaimed configuration. Sections are <br />presented on Figure 2.2-7. Calculations and assumptions are provided in Appendix M(vii). The <br />diversion and collection ditches around the waste disposal area (segments C, D, F, I and J) are <br />designed to handle the 100-year event. The first two ditches constructed were the upper <br />diversion ditch and the ditch along the toe of the pile. The upper diversion ditch was constructed <br />as high above the valley floor as possible. The diversion and collection ditches will be <br />constructed according to the design plans, with rip-rap if specified, even though they may need <br />• to be relocated in the future. Temporary ditch dimensions may diverge from the permanent ditch <br />design as long as there is a capacity adequate for design flow plus required freeboard. <br />Runoff from the upland area is directed to the sediment pond. The site drainage diverts <br />runoff from the upland areas around the pile in channels designed to handle the 100-year <br />event. <br />Sedimentation Pond <br />The sediment pond and the general drainage plan for the waste disposal site were <br />prepared under the direction of J. E. Stover, Colorado Professional Engineer, No. 19230. <br />The total drainage area associated with the proposed site is approximately 23.7 acres. <br />The area was divided into separate watersheds draining into diversion channels designed to <br />carry peak flows generated from the 10-year and 100-year precipitation events. These drainage <br />areas are indicated on Figure 2.2-6. Drainage of the eastern portion of the upland area (7.4 <br />acres) has been diverted to flow beneath the existing haul road, through CMP-3, and joins a <br />natural drainage channel. Drainage from the western portion of the upland area (O.t3) acres is <br />diverted away from the sediment pond by berms. <br />TR-22 2-12 05/07 <br />