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for the uncertainty of a feasibility level study. An additional 20 per- cent has been added to the construction estimate to account for engineer- ing and design, construction supervision and administration, engineering during construction, site geologic explorations, topographic surveys, and miscellaneous costs. The total job cost for Alternate No. lA is $782,900. b. This design, as studied and estimated, includes the trash shear boom constructed from logs (see Plate 14 for details). The log boom, designated as Option A, is considered an appropriate design choice. Option 6, a Slickbar trash boom may also prove to be appropriate for this installation. If so, the selection of Option B would be a substantial cost savings to the project. The final choice of trash boom will be made during preparation of plans and specifications. c. The design life of this project is estimated as 50 years, taking into consideration the age (68 years, old) of the existing dam structure. During the lif a of the project, the large mechanical equipment items should only require proper maintenance. The only item that would require replacement during the project life is the log trash shear boom. Based on a study of trash shear booms at a Corps of Engi- neers dam, the life cycle cost is lowest for a log and timber type boom. The log and timber components have a 10-year life and the boom cable has a 25-year 1 ife. All other components have a design 1 ife longer than 50 years and would not require replacement. The present worth of the trash shear boom replacement costs far this alternate is $34,000. D. Alternate No. 2. 1. Description of Ma_ior Features. a. This alternate closely relates to preliminary Alternate A described previously. This fishway is a short, experimental fish ladder that would determine if the two target species will be attracted to and ascend the structure. The ladder is actually an abbreviated ver- sion of Alternate No. 1. The west entrance leg and junction pool have the same configuration as the full-size ladder. From the entrance, fish climb four ladder pools to the junction pool. This ladder also has pro- visions to adjust the length and number of pools (refer to paragraph 3, Operational Flexibility). Also, if this experimental ladder proved suc- cessful in attracting and moving fish upstream through the pools, the full-size ladder configuration (as described in Alternate No. 1) could be added to the experimental ladder structure. b. This alternate locates the trap in the junction pool. The fish find their way into the trap through a U-shaped notch in the trap structure. To transport fish to the upstream pool, a mechanical • hoist will lift the trap and swing it to the upstream side of the dam and ladder, and the fish are then released. 22