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is to establish a need river channel to attract fish to the right bank ladder, remove sediment from the fishway exit area, and provide addi- tional operational control for RWPC. Also, as flashboards are installed on the dam crest, their placement should start at the left bank (looking downstream) and progress toward the right bank. This should keep the attraction flow, created by spilling of water over the crest, near the fish ladder. This sequence of placing flashboards is presently utilized by RWPC. (b) Bar screen may be installed across all four power canal headgates. The head loss through the screens is approximately 0.2 foot with all gates fully open. This bar screen will not be installed until it is determined that the ladder successfully passes fish into the f orebay. (c) The construction of this alternate will not interfere with RWPC operations. The bar screen installation, if necessary, would be scheduled to coincide with the dewatering of the ponder canal for maintenance. (d) RWPC will be asked to continue their efforts for removing trash at the dam. (2) Impacts Affecting FWS. (a) FWS will operate and maintain the fishway facility. This alternate will require that fish be released from the trap periodically (check trap every day during migration season), weir boards be installed or removed, an auxiliary flow valve and entrance slide gates be adjusted, and debris be removed from the fish ladder trashrack. (b) Also, some maintenance of mechanical equipment (valve, slide gates, fish- hoist) is required intermittently to keep these items in proper working order. 5. Estimate of Costs. a. Table 5, Estimate, Alternate No. 3, presents the materials and installation costs of the fish ladder, bar screen, and louver. At the feasibility study level, a contingency factor of 25 percent is added to the materials and installation costs to account for the uncertainty of a feasibility level study. An additional 20 percent has been added to the construction estimate to account for engineering and- design, construction supervision and administration, engineering during construction, site geologic explorations, topographic surveys, 30 •