C153604 Feasibility Study - Laserfiche WebLink

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. . The major components in the facilities design are the embankment slope stability, the embankment seepage control and filter design, the outlet conduit hydraulics, and the design of the concrete structures associated with the outlet conduit, The embankment slope stability analysis is based upon the geotechnical properties of the expected embankment fill material and the expected phreatic water surface within the embankment fill under operating conditions, The stability analysis dictates upstream and downstream fill slopes, and type and location of filter drains, The proposed embankment fill material classification is described by Kumar, and is reflective of the locally available fill materials, The enclosed report by Kumar discusses the stability analysis and embankment materials (Appendix I), . . . The location and construction of the filter drain system Is also discussed in the attached report by Kumar (Appendix I), The filter design is based upon the standard filter criteria originally proposed by K, Terzaghi, which is recommended by the U, S. Bureau of Reclamation (USBR) in "Design of Small Dams," and by the State Engineer in the "Design Review Manual." -The use of a filter sand which meets the gradation requirements of ASTM C33 Concrete Sand Is also approved by the USSR and the State, Based upon previous investigations and repairs for Julesburg Dams No, 2 and 3, we believe embankment seepage is generally very minor, or occurs through sand or shale lenses within the embankment fill. Foundation seepage generally constitutes the majority of the seepage from the reservoir, and occurs through cracks, fractures and joints in the foundation bedrock, This type of foundation seepage has also been observed in the exposed foundation bedrock adjacent to thelerminal end of the outlet conduit. Design seepage flow rates for the Dam No, 4 drain system will be determined based upon correlation to actual observed seepage rates from Dams No.2 and 3, with an appropriate factor of safety added, . . . The outlet tunnel conduit hydraulics were determined by application of the Bernoulli equation to the proposed design, Minor losses were estimated from various published references including "Design of Small Dams" by the USSR, "Handbook of Hydraulics" by Brater and King, and "Practical Hydraulics" by A. L. Simon. The Manning's equation was used for estimation of frictional losses within the conduit, with an "n" factor of 0.015 assuming wood formed concrete. . . The concrete conduit structures associated with the outlet tunnel, gate tower, intake structure, wing walls and headwalls will be designed to meet extreme conditions of operation. The outlet tunnel, tower and walls will be designed to withstand full dam height saturated soil loadings, 16 .