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I I I I I I I I I I I I I I I I I I I Borrow Areas , The soils encountered In borings in the proposed borrow areas are predominantly c1ciy and weathered shale. These materials are highly impermeable and jwould be excellent for construction of a dam and they are present in sufficiert quantity to construct the proposed dam. These materials could be excavated to approximately fifteen feet below existing grade. I I Slope Stability i I I I Slope stability an~lyses were conducted for the dam cross-section shown in Figure 4 using soil properties determined from the testing of the materials I sampled from the proposed reservoir location. The slopes shown on the typical cross-section me~t the State's stability requirements for dam safety. Complete results of the stability analyses are in the Geotechnical Report in Appendix C. Summary I Based on subsurface investigation, testing, and analysis, the site appears I suitable for the! construction of the proposed reservoir. Sound, highly impermeable foun~ation materials were encountered at relatively shallow depths at the location of the proposed dam and suitable clay borrow materials are available in sufficibnt quantity for construction of the dam. A complete report of the geotechnical iMvestigation is contained in Appendix C. , I Geologic Evalua~ion I I A geologic asses~ment was made for the Dry Creek Reservoir site. The site appears to be geologically simple and straightforward, based on a map study and limited field inve~tigations, with no lithologies, geologic structures or other physical features: that would complicate the construction of a dam. The lithologies presen~ would likely be relatively impermeable, and should provide adequate dam co~struction material. I More specific geologic information is contained in Appendix D. I Mineral Resources , Northeastern Colorado contains various economical mineral resources including I petroleum, natur$1 gas, uranium, gravel and crushed-rock aggregate, and limestone. Gravel and crushed-rock aggregates are currently mined from various localities in Nortbern Colorado, but only small amounts exist on this site. Limestone can be: mined from the Niobrara Formation. This formation exists on the site, but no inining is conducted there currently. Uranium deposits are known to exist irl the Fox Hill Sandstone and Laramie Formations in Larimer County. Currentl~ there are no mineral resources being extracted from this site Dry Creek Reserv'oir Feasibility Study 12