| OCR Text |
Show Dam Crest Elevation (feet) 6,400 6,375 6,325 6,365 Approximate Reservoir Capacity (acre-feet) 2,500 1,600 6,315 600 Normal Max. Res. W.S. El. (feet) 6,390 The plan and typical conceptual cross-section for the case with the dam crest at elevation 6,400 feet are shown on Figures 4.3-2 and 4.3-3, respectively. Cross-sections for the lower crest levels are similar to the maximum section. The dam on Dry Fork Creek is designed as a zoned earthfill dam. For the conceptual design studies, the upstream and downstream slopes were selected to be 2.S(H):l(V) and 2.25(H):l(V), respectively. Total embankment volumes and heights of the three cases are as follows: Dam Crest Elevation (feet) 6,400 6,375 6,325 Total In-Place Volume (cubic iards) 2,282,000 1,681,000 869,000 Max. Height Above Foundation (feet) 290 265 215 2. Embankment Design - The various zones of the dam are discussed in the following paragraphs. a. Zone l - The central impervious core of the dam (Zone l) is founded on bedrock. A sufficient quantity of suitably impervious local material has not been verified. Therefore, for the purpose of cost estimation, Zone 1 material will consist of silty clay, which is hauled approximately 13 miles to the damsite from the clay borrow area. The Zone 1 core is relatively thin in order to reduce costs. b. Zone 2 - The shells (Zone 2) will consist of locally available sand and gravel. If sufficient quantities of soil materials suitable for Zone 2 do not occur locally, then a quarry may have to be developed to provide rockfill for Zone 2. 4 - 26 |
