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Geohydrolooy • Twenty-one existing wells were utilized by Colorado State University for the purpose of studying the geohydrology of the surficial, Laramie coal aquifer. In addition, one well was constructed as part of a test dewatering effort of the fluvial sends in the shop area and two wells were constructed into the Fox Hills Sandstone to supply water for the project. The location of all wells in the study are noted on Meps 4.6.3 (a) and 4.6.3 <g). Several types of aquifer testa were conducted on the teat wells. The Ennis Draw deposits possess tranamisaivities of 14,300 to 19,700 gpd'/ft.; the Laramie shale overburden, 2.5 tc 34 gpd/f t.; the coal, 1.8 to 236 gpd/f t.; and the Fox Hills Sandstone, 1,630 to 2,340 gpd/ft. (See Appendix A, McWhorter, page 18>. 4.5.2 Upper Moat Aquifer Aquifer Extent and Piezometric Surface All the above described aquifers with the exception of the Ennis Draw fluvial subsurface water system ere present under the entire area of the proposed project site. The blow sand and fluvial sand thickens eastward across the project to its greatest thickness in Ennis Draw. The bedrock aquifers ere relatively uniform in thickness and dip westward into the Denver Basin. The water table aquifer of Ennis Draw generally follows the fell of the land surface toward the north. The piezometric surface of the Laramie Shales slopes toward the northeast (Appendix A, McWhorter, page 27 Map 4.6.3 (e). The coal piezometric surface possesses a northwest/southeast oriented divide (Appendix A, McWhorter, p. 28). Both of the latter two aquifers are believed to discharge in the lower depths of Ennis Draw. 4.5.3 Existing Uaes~Domestic Weller Existing uses of ground water in the project area are for domestic supply and livestock watering. Data collected from 24 wells (Appendix I-1, McWhorter, p. 100) indicated that all ground-water for such uses are derived from the Ennir s Draw alluVm and the Fox Hiller Sen 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 walla 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. -27-