2005-04-08_GENERAL DOCUMENTS - C1980007

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The West Elk mining operation is adjacent to Sylvester Gulch, Lone Pine Gulch, and Gribble Gulch, which are ephemeral streams that flow directly to the North Fork. No flow has been observed in Lone Pine Gulch for a period of several years. Sylvester Gulch has a drainage area of 4.25 square miles. The hydrologic yield of Sylvester Gulch is low compared to the other watersheds in the West Elk life-of--mine area. This is due to the fact that it drains an area which is lower in elevation and has gentler slopes. To the south most of the West Elk Mine underlies the Minnesota Creek drainage. The Minnesota Creek basin is a significant drainage system occurring in the southern part of the five-year permit area, and within the life-of--mine coal lease boundary. Minnesota Creek and its tributaries drain the southern portion of the coal lease area. These tributaries include Horse Creek, South Prong, Lick Creek, Dry Fork, and East Fork. Minnesota Creek enters the North Fork of the Gunnison near Paonia. The Minnesota Creek drainage extends approximately 53.5 squaze miles as shown in Figure 3 of this document. The West Elk life-of--mine area is drained by five tributaries to Minnesota Creek. These tributaries include East Fork, Horse Creek, South Prong, Lick Creek, and Dry Fork. Characteristics of the drainages are given in Table 3 of this document. Lick Creek and Dry Fork average slopes are generally steeper and the watersheds aze at higher elevations than those tributary to the North Fork. Based upon streamflows measured in water yeaz 1978, the water yields from these drainages are nearly an order of magnitude greater than that from Sylvester Gulch. The evaluation of flow within the Minnesota Creek drainage can only be considered an approximation due to infiltration and seepage losses, seasonal vaziations in precipitation and potential evaporation and sampling difficulties. Nevertheless, approximately 1,000 acre-feet is annually transferred from the Little Gunnison Creek to the Dry Fork of Minnesota Creek, and the average annual flow of the East Fork of Minnesota Creek is approximately 19,920 acre-feet. Irrigation ditches annually remove about 20,000 acre-feet from Minnesota Creek. Two reservoirs are located within the Minnesota Creek drainage. Minnesota Reservoir is located on the Dry Fork. It has a decreed capacity of 1,285 acre-feet, but the actual capacity may be closer to 500 acre-feet. Beaver Reservoir is located on the East Fork of Minnesota Creek and has an absolute decreed capacity of 1,620 acre-feet and a conditional decree of 522 acre- feet. Both reservoirs store water for irrigation purposes and aze filled during spring runoff. They are usually drained by late August or early September. 49