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Alternative 1 - Upstream Flow Control Only <br />- Provide a slide gate on the existing intake structure. <br />- Extend hydraulic control lines and an air vent from the intake structure to a gate operator <br />in the existing valve house. <br />- Remove existing valve internal components <br />Alternative 2 - Single Mid Dam Section Flow Control <br />- Remove left valve internal components and grout the left pipe <br />- Remove entire right valve, line the right pipe with 24 -inch steel pipe, and install new knife <br />valve on 24 -inch pipe. <br />- Remove existing hydraulic control lines and extend new line to new gate control in the <br />valve house. <br />Alternative 2A <br />- Adds a bulkhead at the intake structure so that the outlet works can be dewatered. <br />Alternative 3 - Dual Mid Dam Section Flow Control <br />- Excavate rock above left pipe for valve operator clearance. <br />- Remove both valves in entirety, line both pipes with 24 -inch steel pipes, and install two <br />new knife valves. <br />- Remove existing hydraulic control lines and extend new lines to new gate controls in the <br />valve house. <br />Alternative 3A <br />- Adds a bulkhead at the intake structure so that the outlet works can be dewatered. <br />Analysis of Alternatives <br />Table 1: Peak Outlet Works Canaritv <br />Alternative <br />Peak Flow with Pool El. 7984.35 <br />(cfs) <br />Pool Elevation Required to <br />Release 40 cfs (ft) <br />Alternative 1 <br />303 <br />7931.6 <br />Alternative 2 or 2A <br />130 <br />7935.7 <br />Alternative 3 or 3A <br />236 <br />7932.2 <br />Note: Approximate peak flow. Assumes control gates /valves fully open. <br />Cost Estimate <br />Cost estimates were developed by estimating quantities of primary elements of the work based on <br />the conceptual -level design concepts. Unit costs were developed from these sources: Published <br />and non - published bid price data for similar work, RS Means Heavy Construction Cost Data for <br />2010, Manufacturer's budgetary price quotes, RJH previous experience. <br />