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STATUS REPURT Redlands Fish Passage Facility January 9, 1987 Background/Status: In late 1984 and early 1985, biological opinions were issued to Federal agencies in response to formal Section 7 consultations for several proposed oil shale projects. As a conservation measure to offset the apparent detrimental impacts of water depletion to a 15-mile reach of occupied habitat on the Colorado River, between River Mile 185 (Palisade, Colorado) and River Mile 17U (confluence witty Gunnison River), the oil companies agreed to fund a fish passage facility at the Redlands Water and Power Company diversion dam, River Mile 3, Gunnison River. This dam has been an impediment to upstrearn migration of fishes since its construction in the early 1900's. FWS believed that opening up an additional 4U miles of the Gunnison River via construction of a fish ladder would be a positive conservation action that would offset certain impacts of water depletion related to oil shale development in the upper Colorado River. In June 1986, FWS contracted with the Corps of Engineers, Walla Walla, Washington District, for a feasibility study of an experimental fish passage facility at the Redlands Diversion Dam on the Gunnison River. The purpose of the study was to determine the most appropriate design for passing Colorado squawfish and razorback sucker over the 12-foot Redlands diversion dam. Nine alternative fish ladder designs were evaluated. A preferred alternative was selected that incorporated the following considerations: (1) little or no information was available on fish passage for Colorado squawfish or razorbacks; i.e., this would be the first attempt to pass these fish; (2) the structure had to be flexible in nature to allow for experimental testing of different ladder slopes, attraction flows, water velocity, etc.; (3) Colorado squaa~fish and razorback suckers are not strong swimmers; (this fact eliminated some passage designs [i.e. denile type] from consideration early in the feasibility study); (4) a provision had to be made to prevent fish that passed over the dam from entering the power canal where they would be subject to mortality in the power turbines; (5) a fish trap was needed to be part of the structure to permit an evaluation of the passage facility; (6) maintenance of the ladder had to be minimal; and (7) the structure could not impact Redlands Water and Power Company's (RWPC) operation. Details of the preferred alternative were discussed with the RWPC and sent out for general review and comment. The Feasibility Study report was finalized by the Corps on December 31, 1986. Cost Cost for the design and construction of the preferred alternative is estimated at $783,000. Uperation and maintenance costs would be about $15,000/year. Costs to evaluate the biological effectiveness of the ladder, including stocking the Gunnison River with Colorado squawfish and razorback sucker, would be about $70,000 for 3 year ($210,000 total).