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<br />./ <br /> <br />.. <br /> <br />2)- ./ <br />"/ <br /> <br />...L..... , <br /> <br />1987. updated meteorology data from Hydrometeorological Report <br />49 were also used in this current study. These results are <br />considered adequate for appraisal/feasibility level designs, but <br />should be further refined prior to specification design. <br /> <br />/' <br />I <br /> <br />Owens Creek Dam and Reservoir <br /> <br />Owens Creek Dam would be located about 22 miles east of <br />Collbran. At a Top of Active Conservation water surface <br />elevation of 8,298.2 feet, the reservoir would impound 25,240 <br />acre-feet of water consisting of 22,010 acre-feet of active <br />storage, 3,000 acre-feet of inactive storage, and 230 acre-feet <br />of dead storage. When full, elevation 8,298.2 feet, the <br />reservoir would inundate about 534 acres of Grand Mesa National <br />Forest land used primarily for summer grazing. A reservoir <br />surcharge storage of 6090 acre-feet above the normal water <br />surface elevation but below the maximum reservoir water surface <br />elevation of 8308.8 feet would be available for temporary storage <br />of flood inflow. Sediment deposition in the reservoir over a <br />100-year period is estimated at 678 acre-feet or less than 5 <br />percent of the total reservoir capacity. Clearing would be <br />required in portions of the reservoir basin which have dense <br />groves of aspen with a few spruce trees along with growths of <br />willows along Buzzard and Owens Creeks. The design of the dam <br />and appurtenant works is shown on the attached Sketch <br />No. 984-D3110-1. <br /> <br />site Geoloqy <br /> <br />Bedrock and Mass Wastinq <br /> <br />The Owens Creek dam site would be aligned a very few degrees <br />west of north across Buzzard Creek, according to a 1964 <br />Construction Material Report. Bedrock under the site is entirely <br />Eocene Wasatch Formation, which has been described as being <br />composed of mostly mudstone, siltstone, or shales with lenticular <br />sandstone. The Wasatch Formation weathers rapidly and mass <br />wasting in the form of landslides and slumping, rather than <br />slopewash or fluvial transport, is common. For example, the <br />proposed left abutment has wet slumped areas both upstream and <br />downstream of the dam axis. . <br /> <br />Surficial Deposits <br /> <br />Five to 20 feet of surficial deposits overlie bedrock in the <br />dam site area. The soils are mostly silts and clays containing <br />numerous basalt cobbles and boulders. In a 1963.materials <br />investigation program, the borrow area (Borrow Area 100) nearest <br />to the damsite axis, 5 auger holes were completed. Laboratory <br /> <br />3 <br />