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(b) Also, some maintenance of mechanical equipment (valves, slide gates, fish hoist) is required intermittently to keep these items in proper working order. 5. Estimate of Costs. a. Table 3, Estimate, Alternate No. 2, presents the materials and installation costs of the fish ladder and bar screen. 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, construe- tion supervision and administration, engineering during construction, site geologic explorations, topographic surveys, and miscellaneous costs. The total job cost for Alternate No. 2 is $410,300. b. This alternate would be abandoned or salvaged if fish .passage testing proved unsuccessful. However, if testing was successful, the replacement costs for the full-size ladder would be similar to Alternate No. 1. Also, the approximate cost of completing the ladder construction would be $550,000. The total cost of two-phase construction is approximately $120,000 more than building Alternate No. 1 in one construction season. E. Alternate No. 3. 1. Description of Major Features. a. This alternate closely relates to the combination of preliminary alternates B and G described previously. This vertical slot/ orifice ladder located on the right bank has a downstream and a side entrance. From the entrance, the ladder climbs 23 pools to the forebay exit. The exit is located approximately 35 feet upstream from the existing dam crest, This ladder also has a floor slope of 1 foot ver- tical to 20 feet horizontal and has provisions to adjust the length and number of pools. The pool length is adjusted by placing or removing lightweight weir boards (refer to paragraph 3, Operational Flexibility). b. The fishway exit area is large enough to accommodate an 8-foot-wide, 16-foot-long, 5-foot-high trap. The fish are guided into the trap through a V-shaped notch in the trap structure. Fish easily find their way into the trap but do not easily find their way out through the notch. The trap allows for exiting or trapping of fish by means of an upstream gate. The downstream end of -the notch can be closed and the fish can be crowded to the water surface for observation or tagging. Fish can also be removed from the ladder, while being contained in the • trap, by means of a hoist, 26