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- 8- WYOMING FUEL COMPANY MUST PROVIDE: 1. LINING OF DIVERSION DITCH E UPON CONSTRUCTION WITH COMPETENT ROCK RZPRAP WITH A DSO OF NOT LESS THAN SIX INCHES, OR 2.' A DESIGN FOR A DITCH COLLECTION SYSTEM, WHZCN WILL ELIMINATE THE NEED FOR TEMPORARY IMPOUNDMENT NO. 1 AND THEREBY REDUCE THE DESIGN FI.oW FOR DITCH E TO THE 10-YEAR, 24-HOUR STORM PEAK FLOW. THIS DESIGN SHALL INCLUDE ALL ASSUMPTIONS, METHODS AND CALCULATIONS NECESSARY TO ASSURE COMPLIANCE WITH . 4.05.3, AND SHALL BE PROVIDED TO THE DIVISION WITHIN 30 DAYS OF PERMIT ISSUANCE. There is an apparent discrepancy between the design information provided for Ditch E in Appendix Q and the existing topography. The cut to establish the ditch alongside the pit highwall will be greatly in excess of three feet, as shown in the design drawing. There will also be considerable material to be moved and no mention is given of the method of disposal of the excavated material. Therefore, the Division imposes the following stipulation: WYOMING FUEL COMPANY WILL PROVIDE A REVISED DESIGN DRAWING OF DIVERSION DITCH E (CROSS-SECTION) WHICH SNOWS THE GREATEST DEPTH OF CUT NECESSARY TO ESTABLISH GRADE AND DESCRIBE THE INTENDED DISPOSITION OF MATERIAL EXCAVATED IN THE CONSTRUCTION, PRIOR TO ANY WORK BEING DONE ON DIVERSION DITCH F.. With the acceptance of the above stipulations, the applicant will be in compliance with all sections of 9.05. Monitoring Wyoming Fuel Company has provided a surface water quality and quantity monitoring station, below all areas of disturbance, in the ephemeral drainage identified as the North Fork of Bolton Draw. [Wyoming Fuel Company has also provided a surface water monitoring site at the culvert under the M&T access road (proposed haul road). The flow data collected during May, 1980 is shown bn Table 13, page 53, Appendix C, Volume I. The two surface water quality reports are located in the Water Quality Reports section of Appendix C, Volume II. Both of the water quality samples were obtained on May 19, 1980. The water quality samples were apparently obtained at times when no flow measurements were made. The flow measurements given do not provide sufficient information to determine the seasonal fluctuation of f1 ow, Wyoming Fuel Company has committed to providing weekly flow estimates during the runoff season (page 80, Volume I). As a crest stage recorder is on site, it is possible to obtain an estimate of the peak flow generated by the Summer convective storm season. This could be accomplished by cleaning the staff after each reading, recharging the cork and monitoring the gauge monthly from May through September. This information would be valuable in showing the seasonal fluctuations in flow and may be useful in verifying peak flow estimates. For this reason, the Division imposes the following stipulation: WYOMING FUEL COMPANY MUST PROVIDE A REPORT TO THE DIVISION ANNUALLY OF WATER QUANTITY MEASUREMENTS MADE AT THE SITE. THESE MEASUREMENTS WILL INCLUDE MONTHLY PEAK FLOWS AS MEASURED BY THE CREST STAGE RECORDER FROM MAY THROUGH SEPTEMBER, AS WELL AS THE WEEKLY WEIR MEASUREMENTS MADE DURING THE RUNOFF SEASON.