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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 /> <br />B.1.2. Freeboard <br /> <br />The main dam embankment has approximately 4,feet of freeboard above the emergency spillway, The <br />saddle dam on the north east side of the reservoir has only 2.5,feet of freeboard. The elevations of each <br />dam are shown on Figure I in Appendix A. <br /> <br />B.1.3. Outlet Conduit. <br /> <br />The downstream portion of the outlet conduit was investigated by the State Engineer using a camera, The <br />outlet appears to be concrete and there did not appear to be any major problems identified by this <br />investigation. The conduit is somewhat deteriorated however and there is some question as to whether the <br />upstream portion is a metal conduit or concrete. As far as anyone knows the conduit has never been <br />replaced on this dam and the upstream portion has never been inspected. <br /> <br />The downstream headwall at the end of the conduit has some seepage exiting around it and is somewhat <br />deteriorated. The wall does not appear to be in structural distress but has tilted some over the years, The <br />headwall does retain the slope of the dam and due to the steepness in this area is critical for the downstream <br />stability, <br /> <br />The outlet is not in need of immediate replacement or repair but due to its age is obviously near its useful <br />life span. It is expected that major work will be necessary on the outlet within the next ten years. <br /> <br />B.1.4. Seeoal!:e Control <br /> <br />The seepage at the toe of the dam around the outlet conduit needs to be controlled to ensure piping does <br />not occur through the dam embankment, This seepage can best be controlled by the installation of a toe <br />drain along the dam toe. The drain should be installed approximately 150 feet to the left of the outlet and <br />approximately 100 feet to the right of the outlet. The drain should consist of a plastic pipe enveloped in <br />sand and gravel and placed at a depth approximately four feet below grade. The gravel envelop should <br />extend to near the ground surface and the drain should be placed as close to the dam toe as possible, <br /> <br />Measuring weirs should be placed at the end of the toe drains to allow monitoring of the seepage with <br />changes in reservoir water levels. <br /> <br />B.1.5. Soillwav Evaluation. <br /> <br />I <br />I <br />I <br /> <br />The spillway was analyzed by the State Engineer and was found to be inadequate to pass the 50% PMP <br />flood. The existing emergency spillway on the right side of the dam is only 40,feet in width and it is <br />expected that a spillway at least 150, feet in width may be required. The existing spillway could be <br />enlarged to as much as 150,feet in width in the area to the left of the existing spillway, If more width is <br />required, a secondary spillway may have to be added on the left side of the dam, The saddle dam area <br />would be an appropriate area to provide additional spillway if an easement could be obtained from the <br />property owners, It is our understanding however this is not feasible due to conflicts with certain property <br />owners. <br /> <br />Adding a spillway on the left side of the dam may also require an easement to spill across the field below <br />the dam. The easement would only be required from the spillway to the point at which the flows enter the <br /> <br />5 <br /> <br />I <br />