2011-10-17_REVISION - C1980007 (2)

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area, other than the infiltration gallery which supplies domestic water for the town of Somerset and mine water for Oxbow Mining. A description of the surface water system can be found in Section 2.04.7 of the permit document. Supporting information is contained in Map 34, which illustrates the drainages associated with the WEM coal lease area, Map 37, which delineates the location of all known springs on the coal lease area, and Map 36, which shows the reservoirs and irrigation ditches associated with the Minnesota Creek Basin. A description of the surface water occurrence and mining impacts on adjacent areas can be found in the "Probable Hydrologic Consequences of Mining" section of this document, and the "Cumulative Hydrologic Impact Study" document for this mine area. All of the streams draining the West Elk Mine permit area are tributaries to the North Fork of the Gunnison River. Lone Pine Gulch and Gribble Gulch are ephemeral streams draining the northern portion of the permit area. Sylvester Gulch has perennial flows in its lower reaches through the mine area. Minnesota Creek and its tributaries, Horse Creek, South Prong, Lick Creek, Dry Fork, and East Fork, drain the southern portion of the permit area. Deep Creek drains the eastern portion of the permit area. Minnesota Creek enters the North Fork of the Gunnison River near Paonia. The overall drainage exhibits a dendritic drainage pattern with steep channels. Horse Creek, South Prong of the East Fork, and Deep Creek are perennial streams. Lick Creek, Upper Dry Fork, upper Sylvester Gulch and Gribble Gulch are ephemeral streams. Minnesota Reservoir controls much of the flow in the lower Dry Fork of Minnesota Creek, and Beaver Reservoir controls the flow in the East Fork of Minnesota Creek. Lone Pine Gulch has no evidence of recent flow; therefore, no gaging station has been constructed. Even when all of the six gaged watersheds were found to be flowing, Lone Pine Gulch showed no flow or evidence of flow. Raven Creek flows through the extreme northeast corner of the permit area, but a permit stipulation expressly forbids mining activities to expand the affected area into the riparian zone of the creek. There are three different types of springs within the permit area: alluvial, colluvial, and bedrock springs. A study of the groundwater system at the West Elk Mine by Mayo & Associates found 83 different springs within the existing permit area in 1999. From the identified springs, 65% of the cumulative discharge volume comes from superficial springs in alluvium and /or colluvium. Only 5% of the discharge comes from units of the Upper and Lower Coal member. The flow rates of these springs are highly seasonal with peak flows occurring during wet weather conditions. Reservoirs and stock ponds also occur within or near the permit area. Minnesota Reservoir, on the Dry Fork of Minnesota Creek, is centrally located within the coal permit area. Beaver Reservoir on the East Fork of Minnesota Creek is located near the southwestern boundary of the coal lease area. In addition to the storage reservoirs in the area of the West Elk Mine, a total of 61 stock water • impoundments have been identified in or adjacent to the permit area as of 2006. Map 37 of the permit document shows the locations of the known stock water ponds. These ponds generally do 11