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<br /> <br />Page | 9 <br /> <br /> <br />Georgetown Lake Dam Outlet Modification Project – Georgetown Colorado <br />Alternate #1 – Slide Gate : The slide gate option involves installing a new slide gate <br />adjacent to the existing 48-inch slide gate on the upstream face of the spillway at <br />approximately the same invert elevation as the existing gate. According to the Outlet <br />Study, a new 48- inch square gate could pass the maximum flow increment of 225 c.f.s., <br />and can be throttled to reduce flow through the opening to match the 75 c.f.s. and 150 <br />c.f.s. flow increments. <br /> <br />Alternate #2 – By-Pass Pipe Through Dam : The by-pass pipe alternative through the <br />dam involves installing a new pipe through the left (looking downstream or West) <br />abutment of the spillway. A 48-inch diameter pipe could discharge the maximum flow <br />increment of 225 c.f.s. A 42-inch diameter gate valve would be included on the <br />downstream end of the pipe to regulate flows through the pipe, and a 48-inch square <br />slide gate would be included on the upstream end of the pipe to act as a bulkhead. The <br />invert of the new pipe would be located approximately thirteen feet below the crest of <br />the spillway with an inlet located on the left abutment wall. Installation of the pipe in <br />the existing embankment involves trenching through the embankment, installing the <br />pipe, then backfilling and compacting the embankment over the pipe. The existing <br />spillway structure concrete and embankment dam were designed for a specific <br />application, and considerations should be made if the design is altered during <br />construction of the new pipeline. A 48-inch bulkhead gate at the inlet and a 42-inch <br />gate valve at the outlet would be included to operate the by-pass line. <br /> <br />Alternate #3 – By-Pass Pipe Around Dam : The by-pass pipe alternative around the dam <br />involves installing a new 54-inch diameter pipe around the left (West) abutment of the <br />dam. Based on the topography, an inlet structure would be located approximately 120-ft <br />upstream of the dam on the West side of the reservoir. The pipe would discharge into