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Table 2: 0 Anion of Probable Construction Costs <br />Alternative <br />Opinion of Probable Construction Costs ($) <br />Alternative 1 <br />214,000 <br />Alternative 2 <br />218,000 <br />Alternative 2A <br />191,000 <br />Alternative 3 <br />287,000 <br />Alternative 3A <br />260,000 <br />The alternatives were then evaluated for technical, operational, and economic considerations. <br />Alternative 1 <br />Advantages <br />- Provides the greatest flow capacity <br />- The mid dam section pipes remain in place where they could potentially be lined <br />and fitted with valves in the future. <br />- Work could be performed under full or partial reservoir head, eliminating the need <br />to drain the reservoir. <br />Disadvantages <br />- Construction requires a barge and lift with divers. <br />- Future gate access requires divers. <br />- Does not provide redundancy in flow control for outlet repairs or backup closure. <br />Alternative 2 . <br />Advantages <br />- Provides precise flow control even at small flow volumes. <br />Disadvantages <br />- Provides the lowest flow capacity. <br />- Parallel valve option is permanently closed. <br />- Does not provide redundancy in flow control for gate repairs or backup closure. <br />- Relies on the unknown structural integrity of the existing concrete bulkhead. If the <br />bulkhead were to fail, it would result in draining the reservoir in an uncontrolled <br />manner. <br />- Requires reservoir drawdown and stream diversion. <br />Alternative 2A <br />Advantages <br />- Provides precise flow control even at small flow volumes. <br />- Provides a means to dewater for valve maintenance. <br />- Work could be performed under full or partial reservoir head, eliminating the need <br />to drain the reservoir. <br />- Would be the least expensive to construct. <br />Disadvantages <br />- Construction requires a barge and lift with divers. <br />- Provides the lowest flow capacity. <br />- Parallel valve option is permanently closed. <br />- Bulkhead closure may require crane and divers and will increase routine operation <br />