2007-07-30_GENERAL DOCUMENTS - C1981041

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sediment and drainage control facilities at various locations. A segment of the Coal Creek permanent diversion is to be re-constructed following reclamation of Pond 6 and Pond 10, and a final reclamation segment of the Coal Gulch permanent diversion is to be constructed following removal of Pond t 1. A permanent reconstructed channel segment has been completed at the North Decline Reclaimed, with the exception that channel berm breaks will be installed prior to final bond release. Several permanent ephemeral channels are to be constructed across the North Portal reclaimed area following removal ofthe temporary upper diversion ditch and reclamation of Pond 13. Finally, several permanent drainage channels are to be constructed in association with South Portal azea reclamation grading and subsequent removal of Sediment Ponds 8 and 9. C. Stream Channel Diversions Construction of the Cameo Refuse Disposal Areas involved the installation of a permanent ephemeral stream channel diversion along a segment of Coal Canyon in the vicinity ofthe refuse areas. A total of approximately 600 feet of the Coal Canyon drainage was diverted. The channel segment was originally constructed with four rock drop stmctures to minimize erosion along the segment. The channel obstructions caused by the drop structure installations were determined by the Division to be inappropriate, due to the potential for high flow to escape the channel. As a result, modified interim and final designs have been approved. The interim channel was constructed by removing the rock structures and grading the channel segment to a uniform gradient in 2002. The final design provides for re-alignment of the upper segment of the channel section to allow installation of a meander in the vicinity of Sediment Pond 6, in conjunction with Pond 6 reclamation. Designs are located in Appendix 13-2 and channel locations and cross sections are shown on Exhibit 51, 52, 53 and 55. Pursuant to TR-42 approved in 2003, the Division approved the installation of a riprap transition zone at a "nick- point" in a lower segment of the Coal Creek channel, in the vicinity of the former Haul Road 2 channel crossing. In addition to the permanent diversion of Coal Creek mentioned above, the Division has approved construction of a riprapped permanent channel diversion beginning at the ephemeral drainage above the Roadside South Mine Portal Bench Area, and extending to the south above the Roadside Refuse Disposal Area (RSRDA) and down along the south end of the RSRDA. This diversion was constructed in 2002. A third major permanent channel diversion has been approved for the lower segment of Coal Gulch in the vicinity of Sediment Pond 11. Excavation of soil from the adjacent Cameo Borrow Area has resulted in a "hanging segment" of the lower Coal Gulch ephemeral drainage. Upon reclamation of Sediment Pond 11, the lower segment of the channel will be re-aligned via a riprap channel segment to direct the drainage to the bottom ofthe excavated borrow area. This will result in a topography that is geomorphically stable and appropriate for the permanent drainage configuration. Approval ofa permanent diversion of an ephemeral channel draining less than one square mile has been made for a channel in the vicinity of the Two West Portals reclaimed area. The following Findings I-3 apply to the Coal Creek and Coal Gulch diversions and the South Portal area permanent diversion; Finding 4 applies to the Two West Portals permanent diversion. Permit Revision No. 3 Permit No. C-1981-041 July 30, 2007 Page 23