2009-10-06_PERMIT FILE - C1980005 (16)

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• • • As part of the final reclamation plan for the Seneca H Mine, this appendix outlines the design procedures and final designs for postmining channels. The designs are for both planned and existing channels. 1.0 INTRODUCTION The locations of the channels are shown on Exhibit 7-19, Postmining Drainage Control, as well as Exhibit 13-2A, Postmining Topography and Permanent Features. The profile for each channel is shown on Exhibit 7-20, Postmining Channel Profiles. Appendix A, SEDCAD+ Demonstrations, contains the postmine hydrologic demonstrations and Appendix B, Channel Designs, contains the hydraulic calculations for all postmining drainage ditches. Appendix C, Culvert Designs, presents the culvert designs. The following channels were designed: • SII PM-1 • SII PM-2 • SII PM-3 • SII PM-4 • SII PM-5 • SII PM-6 • SII PM-6a • SII PM-6b • SII PM-7 • SII PM-8 • SII PM-15 • SII PM-8 V-Ditch • SII PM-16 • SII PM-9 • SII PM-17 • SII PM-10 • SII PM-18 • SII PM-11 • SII PM-19 • SII PM-12 • SII PM-20 • SII PM-13 • SII PM-21 • SII PM-13a • SII PM-22 • SII PM-14 • SII PM-23 All of these channels will be permanent and were designed to control the peak discharge from the 10-year, 24-hour storm event. Because parts of channel SIIPM-4 is adjacent to a fill area, it was designed to control the peak discharge from the 100-year, 24-hour storm event. Because the total watershed area for the lower part of SIIPM-1 is greater than one square mile it also was designed to control the peak discharge from the 100-year, 24-hour storm event in accordance with Rule 4.05.4. In addition to the permanent channels, the following existing culverts were evaluated as permanent structures: • 2A • 29A • 2AA • 30A • 3A • 32A • 9A • 33A • 12A • 45A • 13A • 47A • 15A • 62A • 18A • A3 • 19A • A5 • 24A TR-51 7-12-1 Revised 09/09