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• The water table aquifer of Ermis Draw generally follows the fall of the land surface toward the north. The piezometric surface of the Laramie Shales slopes toward the northeast (Appendix I-l, McWhorter, page 27 and Appendix I-2). The coal piezometric surface possesses anorthwest/southeast oriented divide (Appendix I- l, McWhorter, page 28). Both of the latter two aquifers are believed to discharge in the lower depths of Ennis Draw. Water Ouality Water quality data has been accumulated from all aquifers (Appendix I-l, McWhorter, Page 29 through 35 and Appendix J-I ). Generally, the waters in the Laramie Shales and the target coal would be unacceptable for most uses. The total dissolved solids concentrations were from 1500 to 7000+ mg/l. In addition, the sodium absorption ratios (SAR) were 10 to 18, making the water mostly unsuitable for irrigation. The Fox Hills water possessed TDS of 650f mg/1, while Ennis Draw ground-water TDS is 750 - 1000 mg/l . Existin Uses Existing uses of ground water in the project area are for domestic supply and livestock watering. Data collected from 24 wells (Appendix I-l, McWhorter, Page • 100) indicated that all ground water for such uses are derived from the Ennis Draw alluvium and the Fox Hills Sandstone. Water likely is not utilized from the Laramie shales or coal due to its poor quality. Refer to Appendix D-1 for map showing locations of wells in the vicinity of the extension area. There are no water supply intakes, ditches, reserves or other surface water bodies within a one mile radius of the affected area. In addition, there are no irrigation ditches, or constructed or natural draws within the proposed extension area. Surface Water The mine is located adjacent to Ennis Draw, a tributary to Box Elder Creek which flows into the South Platte River near Kersey, Colorado. There is no evidence of surface runoff in the vicinity of the site. Essentially all precipitation infiltrates the highly permeable mantle of sand. No water-formed erosional features are evident, not even small rills or gullies. Ennis Draw is a broad, flat bottomed depression with no observable channel or gully and shows no evidence of the existence of surface flows. • 50