2000-03-10_GENERAL DOCUMENTS - C1980007

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water year 1977. Flow records for the North Fork of the Gunnison River near Somerset are given in Table 1 of this document. Water quality parameters for the North Fork are given in Table 2 of this document. As indicated, water in the North Fork is a calcium bicarbonate type. There are also moderate levels of sulfate and salinity averages less than 100 mg/I. The West Elk surface facilities are located 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 Gribble 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. Monitoring of Gribble Gulch, which could potentially be impacted by mining in Jumbo Mountain, began in September 1993. Most of the West Elk mine area underlies the Minnesota Creek drainage to the south. The Minnesota Creek basin is a significant drainage system occurring in [he 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 [he 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 square 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 are at higher elevations than those tributary to the North Fork. Based upon streamflows measured in water year 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 variations 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 through the Deep Creek Ditch, and the average annual flow of the East Fork of Minnesota Creek is approximately 19,920 32