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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />ODll13 <br /> <br />Adequate material for RCC aggregate is available in proximity to the damsite. <br />All uvi al sand and gravel from requi red excavati on for the dam and spi 11 way <br />woul d be suppl emented by addi ti onal gravel borrowed from the ri verbed upstream <br />or downstream of the dam. <br /> <br />Reservoir slope stability and reservoir permeability are not expected to be of <br />concern for the Veatch Gulch Project. <br /> <br />The cost estimates show that the Veatch Gul ch Dam ranks 1 ast among the four <br />sites studied in the upper canyon stretch of the White River, for all <br />reservoir capacities evaluated. It compares most favorably to the Warner <br />Point and Canyon sites at a storage capacity of 150,000 and 300,000 acre-feet, <br />but remains about 40 percent more expensive. <br /> <br />Canyon Dam <br />The surface i nvesti gati on at the Canyon Dam si te showed that an acceptabl e <br />foundati on for an embankment dam exi sts at the upper of the two centerl i nes <br />drilled. The foundation for an RCC gravity dam is questionable due to the <br />apparent low compressive strength of the sandstone of the Entrada Formation. <br />Further investigation and testing would be necessary to determine the <br />feasibility of an RCC design. In addition, the height of the RCC alternative <br />might be limited to the elevation of the contact between the hard sandstone of <br />the lower Morri son Formati on and the hi ghly weathered green si ltstone and <br />sandstone of the upper part of that uni t. The downstream centerl i ne is <br />infeasible due to a deep landsl ide on the left abutment and an intensely <br />fractured and weathered zone, associated with faulting, on the right abutment. <br /> <br />The seismic refraction lines across the valley floor showed the alluvium at <br />the site to be thinner than at any of the other sites studied in the upper <br />canyon. Although the boreholes at the base of the abutments revealed the <br />bedrock to be about 40 feet deep, in the center of the valley it is apparently <br />only 10 to 20 feet deep. The 1 esser depth to bedrock shoul d have a posi ti ve <br />effect on the economic feasibility of the site. <br /> <br />Geologic mapping at the site identified three northwest trending normal faults <br />within one mile of the dam. The faults are not thought to be potentially <br /> <br />E-10 <br />