2012-01-26_PERMIT FILE - C1981018A

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Below the confluence of Scullion Gulch with the White River exist four diversion and/or use points. Seven • and 49 one hundredths cubic feet per second may be diverted at two points for irrigation. Aright also exists for the miscellaneous use of 12.00 cubic feet per second in this reach of the river. The final diversion point has a combined right to 1240.0 cubic feet per second and 95,000 acre-feet of water for storage in the proposed Rangely Reservoir and use in the Douglas Canal and the Rangely Power Conduit. II,C.5 Probable Hvdrologlc Consequences II.C.5.a Impact on Surface Water At full production, the Deserado mine is projected to utilize approximately 552 acre-feet of water annually for domestic and industrial purpose. Table II.C-15 gives a breakdown of the water source and use by various categories. This water is stored near the portal areas in a 1.6million-gallon raw water tank and a 40,000-gallon domestic (treated) water tank for domestic use, dust suppression, fire control, coal washing, etc. Water is withdrawn from the White River from a lagoon in the alluvium. The effect is to reduce the flow of the White River. The effect of this withdrawal on the White River alluvium and uses in the area is discussed in Section II.D on alluvial valleys. It is assumed that the withdrawal rate of 552 acre-feet per year can be converted to 0.763 cubic foot per second (601 gallons per minute). This represents about 0.2 percent of the average annual flow of the White River above Rangely, Colorado. • Utilizing the long-tens flow duration curve of the White River above Rangely, Colorado (Figure II.C-6), the projected withdrawal rate of 0.763 cubic foot per second will reduce the flow rate of the White River at the intake point by approximatey 0.73 percent during periods of extremely low flow (i.e., those flow conditions which are equaled or exceeded 99.99 percent of the time). During the 1972 through 1978 period, the average yearly low flow of the White River above Rangely was 245 cfs. Even if the expected 0.763 cfs used by the mine was taken entirely from the river, the low flow would only decrease by 0.31 percent to 244.2 cfs. During median flow conditions (available 50 percent of the time), the flow rate will be reduced by only 0.1 percent. Thus, under any circumstances, the impact of mining on the quantity of water in the White River will be minimal. Conflicts with downstream senior Colorado rights would be very rare if they occurred at all, and would be under the jurisdiction of the State of Colorado. As a result of surface facilities associated with mining, local water yields will probably be somewhat increased. However, as will be further noted, because much of this runoff will pass through a sediment pond, some water will be lost to seepage and/or evaporation. The net effect will be minimal, whether an increase or a reduction in runoff occurs. Aquifer tests within the tease area show very low transmissivities. For example, of those tests run on wells completed in the Siltstone and Coal Facies, transmissivities were only 2.9 and 3.3 gpd/ft from wells 310135-4M and the Staley House Well, respectively. Formations are characterized by tight sandstones • Permit Renewal #3 (Rev. 1/00) II.C-80