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Mine facilities should not be endangered from large flood events from these <br />streams. The Deserado Ventilation Entry area is located above the floodplain <br />of the White River, a perennial stream which flows in a southwesterly direction <br />along the southern limit of the permit area. The ventilation entry area will <br />contain three entries, at invert elevation 5,380 feet, which will provide five <br />feet of freeboard above the 500 year flood elevation of 5,375 feet. The two <br />entries at the D-Portal Area will have inverts at elevation 5,636 feet, having <br />four feet of freeboard above the 500 year flood elevation of 5,632 feet (page <br />V-28 ). <br />Discharges for the 2-,'10-, 25-, 50-, and 100 year -24 hour rvn-off events for <br />Scullion Gulch and Red Wash are listed below in Table 1. These are based on <br />information and calculations included in the permit application. Flows have <br />been estimated using the methodology presented in Section 4, Chapter 21 of the <br />Soil Conservation Service National Engineering Handbook. These figures were <br />checked with data presented in Colorado Water Conservation Board Technical <br />Manual No. 1 and appear to be within a reasonable standard error of estimate. <br />Water Use <br />Present surface water use within the two major watersheds of the permit area is <br />restricted to stockponds for livestock and wildlife. Information presented in <br />the Water Rights and Land Use Sections of the pe nnit application indicates that <br />water from the White River has been used to irrigate land in the permit area <br />between the mouths of Red Wash and Scullion Gulch. Additionally, a water right <br />has been appropriated by Western Fuels for withdrawal from White River at this <br />same location for future use in the proposed, Moon Lake-Staley Mine pipeline and <br />reservoir. A second water right obtained by Western Fuels, listed under Moon <br />Lake Power will allow them to withdraw 6 cfs from a diversion point downstream <br />of the mine on the White River near Rangely. (page V-1 of the permit applica- <br />tion). This water supply exceeds the estimated requirements of the mine, and <br />would be available as an alternative water supply should mining operations ad- <br />versely impact the surface water regime. If tension cracks from subsidence <br />cause stock ponds in the Scullion Gulch basin to lose impounded water, for <br />example, supplies from the Rangely diversion point could be trucked to the site <br />until the ponds were repaired or replaced (p. II.C-106b). <br />2 <br />