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extended 10 feet upstream and downstream of each drop structure. Designs are located in <br /> Appendix 13-2 and channel locations and cross sections are shown on Exhibit 51, 52, 53 and <br /> 55. <br /> In addition to the permanent diversion of Coal Creek mentioned above, the Division has <br /> approved construction of a riprapped permanent channel diversion extending from the ephemeral <br /> drainage above the Roadside Refuse Disposal Area to a permanent grated drain located in the <br /> Roadside South coal handling facilities area. The grated drain will open to a 9.5 foot diameter <br /> CMP culvert which will convey drainage flow from the reclaimed site beneath the interstate to <br /> the river. The culvert is currently in place, enclosing the coal conveyor. Construction of the <br /> permanent channel and drain will be conducted in association with final reclamation of the South <br /> Portal facilities area. <br /> The following findings apply to the Coal Creek diversion and the South Portal area ephemeral <br /> drainage permanent diversion. <br /> I. The Division has approved an existing permanent diversion of Coal Creek, and one <br /> permanent diversion of an ephemeral drainage in the South Mine facilities area. These <br /> diversions are consistent with applicable state law, will not diminish downstream water <br /> rights, and will meet the requirements of Rules 4.05.4 and 4.05.18 (4.05.4(4)). <br /> 2. The permanent diversions shall make use of artificial structural controls in order to allow <br /> them to remain in dynamic equilibrium with the drainage basin system. The Division <br /> approved the use of rip-rap drop structures in the channel bottom of the Coal Creek <br /> diversion, and rip-rap channel lining along the South Portal facilities reclaimed area <br /> permanent diversion (4.05.4(4)(b)). <br /> 3. Channel lining structures, retention basins, and artificial channel roughness structures are <br /> proposed for use to control erosion. Artificial structures include rip-rap drop structures in <br /> the Coal Creek diversion;and rip-rap channel lining and a permanent culvert segment for <br /> the South Portal facilities drainage reclamation. These means were approved by the <br /> Division since they are necessary to control erosion, they are stable and will require <br /> infrequent maintenance(4.05.4(2)(a)). <br /> In addition to the permanent diversion of Coal Creek mentioned above, a temporary <br /> diversion has been approved and constructed for an unnamed ephemeral tributary to the <br /> Colorado River located within the 2 West Portal Disturbance Area. The outside bank <br /> closest to the North Portal was built up to prevent the diverted stream from entering the <br /> portal. Bedrock lies close to the bottom of the diverted channel and the channel does not <br /> require armoring. The channel will be returned to its natural configuration upon final <br /> reclamation. <br /> 4. The Division approved the temporary diversion of an ephemeral stream draining less than <br /> one square mile located at the 2 West Portal. This decision is based on a finding that the <br /> proposed diversion meets the requirements of 4.05.18 and 4.05.4,applicable local, State, <br /> and Federal statutes and regulations and that the diversion is designed to safeguard public <br /> safety and to minimize adverse impacts to the hydrologic balance(4.05.4(1) and(4)). <br /> 26 <br />