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The 36-inch diameter culvert conveying flows from the permanent diversion <br />under the mine haul road is not adequate for the 10-year, 24-hour storm. <br />Stipulation No. 12 <br />THE APPLICANT MUST SUBMIT ADEQUATE DESIGNS FOR THE CULVERT CONVEYING <br />FLOWS FROM THE COAL GULCH DIVERSION UNDER THE HAUL ROAD WITHIN <br />THIRTY (30) DAYS OF PERMIT ISSUANCE. THESE DESIGNS MUST BE APPROVED BY <br />THE DIVISION PRIOR TO ANY HAUL ROAD CONSTRUCTION. <br />The two diversions designed to convey undisturbed area drainage around the <br />disturbed area, Diversion Ditches 2 and 3 are adequate as long as 1.0 feet of <br />freeboard is maintained as committed to in the permit application. <br />There are two ditches and several culverts which convey flows from disturbed <br />areas to the sediment pond. During the adequacy review the applicant was <br />asked to present designs for the two ditches. Designs were presented for the <br />east ditch, but not the west ditch. <br />Stipulation No. 13 <br />WITHIN THIRTY (30) DAYS OF PERMIT ISSUANCE AND PRIOR TO ANY ADDITIONAL <br />DISTURBANCE, THE APPLICANT MUST SUBMIT TO THE UIVISION FOR APPROVAL <br />DESIGNS FOR THE WEST DITCH ADEQUATE TO PASS THE FLOWS FROM A 10-YEAR, <br />24-HOUR STORM. THE DESIGNS MUST BE APPROVED IN WRITING BY THE DIVISION <br />PRIOR TO THIS STIPULATION BEING SATISFIED. <br />Peerless Resources, Inc. will pass the flows from the disturbed area through a <br />sediment pond. This pond is an existing sediment pond for which the applicant <br />has provided calculations to prove it is adequate. The pond has been designed <br />to contain the 10-year, 24-hour storm without passage through the emergency <br />spillway as well as sediment storage and projected portal discharges. The <br />sediment volume to be contained was based on a figure of .05 ac/ft per acre of <br />disturbed area. While this figure is lower than the accepted standard of <br />.1 ac/ft per acre of disturbed area, the site conditions and small amount of <br />disturbed area justify use of this number. The applicant must install a staff <br />gage to monitor sediment and ensure cleanout at the 60% level. <br />Stipulation No. 14 <br />THE APPLICANT MUST INSTALL A STAFF GAGE CLEARLY MARKED WITH THE 6U% <br />CLEANOUT ELEVATION IN THE SEDIMENT POND. <br />Throughout the sediment control designs a curve number of 78 is used for <br />undisturbed areas except in conjunction with the sediment pond in which a <br />curve number of 72 is used. The Division has asked for specific justification <br />of the use of 72, however, the applicant has given none. <br />