2007-11-16_GENERAL DOCUMENTS - C1981041 (3)

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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 of the excavated borrow area. This will result in a topography that is geomorphically stable and appropriate for the permanent drainage configuration. Approval of a 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 1-3 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. 1. The Division has approved permanent diversion of a segment of Coal Creek, a segment of Coal Gulch, and permanent diversion of unnamed ephemeral drainages above the South Mine facilities and Roadside Refuse Disturbance area. These diversions are consistent with applicable state law, will not diminish downstream water rights, and will meet the requirements of Rules 4.05.4 and 4.05.18 (4.05.4(4)). 2. The permanent diversions shall make use of artificial structural controls in order to allow them to remain in dynamic equilibrium with the drainage basin system. The Division approves the use of rip-rap channel lining along various segments of these channels. Channel lining structures and artificial channel roughness structures are proposed for use to control erosion. Artificial structures include a rip-rap transition zone structure in the Coal Creek channel at the location of the former Haul Road 2 crossing, and riprap lining along the South Portal facilities permanent diversion and the Coal Gulch permanent diversion segment. These means were approved by the Division since they are necessary to control erosion, they are stable and will require infrequent maintenance (4.05.4(2)(a)). In addition to the permanent diversions mentioned above, a permanent diversion of an ephemeral stream draining less than one square mile has been approved for an unnamed ephemeral tributary to the Colorado River located within the 2 West Portal Disturbance Area. The outside bank closest to the North Portal was built up to prevent the diverted stream from entering the portal. Bedrock lies close to the bottom of the diverted channel and the channel does not require armoring. This decision is based on a finding that the proposed diversion meets the requirements of 4.05.18 and 4.05.4, applicable local, State, Permit Renewal No. 5 24 November 16, 2007