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The West Elk mining operation is adjacent to Sylvester <br /> Gulch and Lone Pine Gulch, which are ephemeral streams <br /> that flow directly to the North Fork. No flow has been <br /> observed in Lone Pine Gulch for a period of several <br /> years. Sylvester Gulch has a drainage area of 4.25 <br /> square miles. The hydrologic yield of Sylvester Gulch <br /> is low compared to the other watersheds in the West Elk <br /> life-of-mine area. This is due to the fact that it <br /> drains an area which is lower in elevation and has <br /> gentler slopes . Most of the West Elk Mine underlies <br /> the Minnesota Creek drainage to the south. <br /> The Minnesota Creek basin is a significant drainage <br /> system occurring south of the five-year permit area, <br /> but within the life-of-mine coal lease boundary. <br /> Minnesota Creek and its tributaries drain the southern <br /> portion of the coal lease area. These tributaries <br /> include Horse Creek, South Prong, Lick Creek, Dry Fork, <br /> and East Fork. Lick Creek and Dry Fork are the only <br /> tributaries of Minnesota Creek which are proposed to be <br /> undermined. The operator has proposed a current plan <br /> of limited extraction in these areas and has developed <br /> a detailed mitigation plan to monitor subsidence and to <br /> compensate for any loss, if any, in vested downstream <br /> water rights. Minnesota Creek enters the North Fork of <br /> the Gunnison near Paonia. <br /> The Minnesota Creek drainage extends approximately <br /> 53.5 square miles (Figure 2) . The West Elk <br /> life-of-mine area is drained by five tributaries to <br /> Minnesota Creek. These tributaries include East Fork, <br /> Horse Creek, South Prong, Lick Creek, and Dry Fork. <br /> Characteristics of the drainages are given in Table 3. <br /> Lick Creek and Dry Fork average slopes are generally <br /> steeper and the watersheds are at higher elevations <br /> than those tributary to the North Fork. Based upon <br /> streamflows measured in water year 1978, the water <br /> yields from these drainages are nearly an order of <br /> magnitude greater than that from Sylvester Gulch. <br /> The evaluation of flow within the Minnesota Creek <br /> drainage can only be considered an approximation due to <br /> infiltration and seepage losses , seasonal variations in <br /> precipitation and potential evaporation and sampling <br /> difficulties . Nevertheless, approximately 1 ,000 <br /> acre-feet is annually transferred from the Little <br /> Gunnison Creek to the Dry Fork of Minnesota Creek, and <br /> the average annual flow of the East Fork of Minnesota <br /> Creek is approximately 19,920 acre-feet. Irrigation <br /> ditches annually remove about 20,000 acre-feet from <br /> Minnesota Creek. <br /> -34- <br />