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Requested flows to match available year's run-off, Hamill says LADDER, tram Page 1 Hamill, director of the Recovery Program for Endangered Fish of the Upper Colorado River Basin, "Blue Mesa is the largest dam that can be reoperated to affect flows in the main stem Colorado River in a posi- tive way," Hamill said, "Most of the reselVoirs in the upper Colorado River Basin are small, and much of the water in those reselVoirs is already committed to other uses. The Gunnison River is an untapped resource for endangered fish." Blue Mesa, which has a 940,800 acre-feet capacity, was completed in 1965 to provide water for irrigation, recreation and generation of electric power, Downstream of Blue Mesa Dam are two more federal dams: Morrow Point, a power-generation unit, and Crystal, which creates power and smooths out the flows of the Gunnison, Operated by the U,S. Bureau of Reclamation, the three dams are called the Wayne N. Aspinall Storage Unit, fonnerly the Curecanti Storage Unit. Fish In Colo. River also would benefit Biologists think the Gunnison River may be important to endangered fish populations, partly because it con- tributes water to the Colorado River, where larger numbers of these fish are found. Current flows through the Colorado River's Grand Valley, just downstream of the mouth of the Gunnison, are not adequate for endan- gered fish, biologists say. Colorado squawfish sometimes are found in the Gunnison below Redlands Diversion Dam, two miles upstream of the Colorado River confluence. The fish also have been located above the dam as recently as 198 L The diversion dam was built in 1918 by Redlands Water and Power Company to provide water for irriga- tion and hydroelecuic power, ' Fish could access 50 more miles Until recently, scientists had all but ignored the Gunnison River as a potential endangered-fish recovery site because the Redlands dam blocked the fishes' migration, A fish ladder could change all that. Allowing existing fish populations to expand into the Gunnison River would restore the fish to their historic range and could enhance populations overall, Hamill said, "Constructing a fish ladder would open up another 50 miles of river for the endangered fish," he said. "Restoring passage for the fish between the Gunnison and Colorado rivers has to be an integral part of any effort to recover endangered fish in the Gunnison," Still, at around $1 million, the con- struction costs are far from inexpen- sive, Biologists say they must first detennine and quanti fy the types of fish habitat in the Gunnison and iden- tify what fish species exist above the dam, The amount and timing of water released from Blue Mesa Dam will be altered so that biologists can evaluate how different flows affect endangered fish downstream. The study, conducted by the Fish and Wildlife Service, Bureau of Reclamation, Western Area Power Administration and Colorado and Utah divisions of wildlife, ultimately will provide data for the Fish and Wildlife SelVice to write a biological opinion on the operation of Blue Mesa Dam, The SelViee currently is in the pro- cess of writing a similar opinion on Flaming Gorge Dam, on the upper Green River in Utah, In the Blue Mesa study, however, various flow regimes wilI be put in place on an experimen- tal basis beginning this spring, long before the opinion is completed, The strategy of implementing the flows for research PW"JlOses is supported by the Bureau of Reclamation, accord- ing to Rick Gold, the Bureau's assistant regional director in Salt Lake City, Competition stiff for Gunnison water Changing the operation of the dam and committing water for endangered fish could affect Gunnison River fish- ing, rafting and water development, Hamill said, For example, while endangered fish seem to benefit from high spring-f1ows and low, stable flows the rest of the year, rafters may favor high flows year-round, And although high flows could 4 make "walk-in" fishing difficult in the lower Gunnison, the biological impacts to the Gold Medal trout fish- ery downstream probably could be minimized if the flows were properly timed, said Colorado Division of Wildlife Researcher Barry Nehring. Timing of the flows is the critical factor for the rainbow trout and koka- nee salmon fishery in Blue Mesa ReselVoir also, according to Division of Wildlife Biologist Dave Langlois. If high flows are put in place during years when there is sufficient run-off from melting snow, the lake fishery probably will not suffer, he said, But operating the dam to create extremely high flows during a drought year could eliminate two-thirds of the water in Blue Mesa Reservoir and could have disastrous effects on the lake fishery, he said, "Blue Mesa is the most important fishing Jake in the Southwest Region," Langlois said. "Politically this is a sensitive issue." The Fish and Wildlife Service does plan to tailor its flow recommenda- tions to match the run-off available each year, Hamill said. For example, in dry years, large releases from the dam may be requested for only one to two weeks. During high-water years, biologists may request large releases over a period of several weeks. Final decisions about operation of the dam rest with the Bureau of Reclamation, The impact on future water devel- opment is unknown, "The question is how much water should be set aside for endangered fish and how much for other purposes," Hamill said. "The biological opinion should tell us how much water the fish need." Groups that may compete for Gunnison River water include the Upper Gunnison Water Conservancy District, Uncompaghre Water Users Association, Bureau of Land Management, Bureau of Reclamation, Western Area Power Administration, Arapahoe County and the National Park SelVice, The Gunnison River research on flows for endangered fish will contin- ue for about five years,