2013-02-01_REVISION - C1981041 (8)

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All conveyance structures within the permit area are designed and constructed in accordance with Rule 4.053. Permanent diversions above coal mine waste banks are designed and constructed in accordance with Rule 4.09.2(7). Table 13 -4 of the application lists all diversion and conveyance ditches along with references to the appropriate exhibits for designs and cross sections. Calculations used to design these structures are given in appendix 13 -2 of the permit application. A number of permanent channels or channel segments have been constructed or will be constructed following reclamation of temporary sediment and drainage control facilities at various locations. As described in greater detail below the Division has approved four permanent channel diversions located in Coal Canyon, Coal Gulch, at the ephemeral drainage above the Roadside South Mine Portal Bench Area, and at an ephemeral channel in the vicinity of the Two West Portals reclaimed area. A permanent reconstructed channel segment has been completed at the North Decline Reclaimed area, in accordance with the approved plan channel berm breaks have been installed. Several permanent ephemeral channels were constructed across the North Portal reclaimed area. The final channel designs were completed with approval of PR -5. The channels are shown on Exhibit 8C Roadside North Portal Post Mining Topography. As part of the redesign the West Diversion Ditch and the East Diversion Ditch will remain as permanent postmine features. Pond 13 was reclaimed when the final ephemeral drainages were constructed in 2012. Finally, several permanent drainage channels were constructed in association with the South Portal area reclamation grading. 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 of the refuse areas. A total of approximately 600 feet of the Coal Canyon drainage was diverted. As part of the design for CRDA -2, the Coal Canyon drainage channel was realigned to provide a more uniform, controlled flow between CRDA 1 and 2. The four rock check dams constructed in the channel have caused significant deposition and necessitated frequent maintenance. In order to assure the channel is in equilibrium with the flow regime, the rock check dams were removed and the excess sediment was harvested and used as refuse cover soil during the 2002 reclamation project. The drainage channel was graded to an approximate uniform grade to the cross sections presented on Exhibits 53 and 55 of the permit document. Berms located along the middle and lower sections were leveled so the channel blends naturally into the adjacent terrain. Berms are not utilized to provide the necessary flow capacity along the segment between the dip section concrete structure at the upper end and the two 81" by 59" culverts at the lower. Additionally, the Pond 6 embankment was built up and fortified with riprap. The rock from the check dams was used for the construction of rock groups placed on the reclaimed surface of CRDA -1 & 2 and other reclamation uses. Since material generated from the Coal Canyon Realignment was utilized for the reclamation of CRDA -2, the realignment was performed concurrently with the 2002 refuse pile reclamation project. During 2003, work was performed in Coal Canyon below the outlets of the large double culverts. Scour protection was provided at the outlet of the culverts. 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. Approximately 700 -feet downstream of the double culverts, a transition zone was installed. See Exhibit 8B and Appendix 13 -2, pages Misc -13 through Misc -22 of the permit document for details 22