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<br />I <br /> <br />I <br />Ie <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br />lie <br /> <br />I <br />II <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br />I- <br /> <br />I <br /> <br />- <br /> <br />- <br /> <br />Appendix A. Field testing also included sampling of overburden soils with thin <br /> <br /> <br />wall tubes and a split spoon sampler (simultaneous with standard penetration <br /> <br /> <br />tests to measure overburden resistance), collection and description of bedrock <br /> <br /> <br />cores, permeability testing in drill holes, refraction seismic and electrical <br /> <br /> <br />resistivity surveys, and excavation of and sampling from borrow material test <br /> <br /> <br />pits. Five seismic traverses and four resistivity soundings were performed on <br /> <br /> <br />the dam, and two seismic traverses were conducted at a potential borrow area. <br /> <br /> <br />Field permeability testing involved single and double packer water tests in <br /> <br /> <br />bedrock. A summary of permeability test results is presented in Appendix A. <br /> <br /> <br />Slotted PVC piezometers were installed in all the test borings to monitor water <br /> <br /> <br />levels in the dam embankment and foundation, and the right abutment. Test pit <br /> <br /> <br />logs and surface geology are depicted on Drawing 1124-3. A geologic section <br /> <br /> <br />and graphic summaries of test boring data, including permeability testing, are <br /> <br /> <br />shown on Drawing 1124-4. <br /> <br />Seismicity of the reservoir site was evaluated through a search of readily <br /> <br /> <br />available published literature. Recorded seismic history and proximity of <br /> <br /> <br />potentially active faults were examined to estimate seismic risk to the site. <br /> <br />Soil samples obtained from the drill holes and test pits were visually <br /> <br /> <br />described and tested in the laboratory for moisture content, Atterburg limits, <br /> <br /> <br />free swell and moisture-density relationships (Standard Proctor compaction <br /> <br /> <br />tests). Gradation analyses were performed on test pit soils and a gravel <br /> <br /> <br />sample from a nearby gravel pit. Gradation and moisture-density curves are <br /> <br /> <br />included in Appendix B. A summary of soil test results is included in Table 1. <br /> <br />A preliminary stability analysis was conducted of the <br /> <br /> <br />section as suggested for the feasibility considerations. <br /> <br /> <br />summarized on Figures 1-0, 2-D and 3-D in Appendix D. <br /> <br />proposed enlarged <br />The analysis is <br /> <br />REGIONAL GEOLOGY <br /> <br />The reservoir is located at the northeastern edge of the Colorado Plateau <br /> <br /> <br />physiographic province. The topography is typically characterized by <br /> <br /> <br />flat-topped plateaus and mesas divided by narrow, deeply incised canyons. <br /> <br />-4- <br />