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Jensen, Utah during the summer. Changes in flow r~leases from Flaming Gorge <br />Dam should not be reduced more than about 14.15 m /s per day to meet target <br />flow of 50.94m3/s. Flows at Jensen shoul~ not fluctuate more than about 25% of <br />the target f]ow (i.e., 38.205 - 63.675 m /s), and remain at that level for the <br />remainder of the summer. Water temperatures in the upper Green River should <br />not differ more than 5°C from the temperature of the Yampa River at Echo Park, <br />and should average 22-25oC in Gray Canyon from July 1 - August 15. <br />Autumn (September 23-December 21) <br />Green River flows of about 50.94 m3/s (25% fluctuation) should be <br />sustained until November of each year, or until most age-0 Colorado squawfish <br />emigrate from backwaters. <br />Winter (December 22-March 20) <br />Under ice conditions, fluctuating flows that promote ice breakup, jams, <br />and shoreline scoring in the mainstream Green River are undesirable for adult <br />fish. It is preferable to stabilize winter flows and to maintain ice cover, <br />once formed, until normal spring breakup. Flows may be lower, but not exceed, <br />ice level. Flaming Gorge releases producing water level fluctuations more than <br />5cm per hour at Echo Park may adversely affect adults. <br />Other Management Options <br />Some additional measures can aid in reducing impacts of Flaming Gorge Dam <br />operations on endangered fishes. The following non-flow related measures are <br />recommended: <br />Bottomland Restoration <br />The importance of flooded bottomlands for fish production has been <br />documented in floodplain rivers worldwide (Welcomme 1979). Many such areas in <br />the upper Green River have been lost by impoundment for agriculture, waterfowl <br />production, and other purposes. Old Charlie Wash, Stewart Lake, and other <br />locations near Ouray National Wildlife Refuge should be evaluated for <br />endangered fish management. Barriers to fish movement should be removed or <br />altered. These areas should be further studied for fish use, and additional <br />plans developed for possible population augmentation at these sites. <br />Flow Re-regulation <br />Recommendations contained herein may be difficult under current operational <br />restraints. However, other options exist for flow re-regulation and thermal <br />enrichment of Flaming Gorge releases. These options should be more fully <br />explored, but include evaluations of re-regulation projects. <br />Control of Introduced Fishes <br />Operation of Flaming Gorge Dam is no doubt aiding the proliferation of <br />introduced fishes, however, little emphasis has been placed on evaluating <br />their impacts on the endangered species. Interactions between native and <br />potentially adverse non-native fishes should be conducted using controlled <br />experimental procedures, and "pest" fishes identified. Habitat use of these <br />pest fishes should be evaluated for development of control measures in part, <br />via operation of Flaming Gorge Dam. It is probable that native fishes are less <br />affected by extreme flows than are non-native fishes, and that moderate flow <br />regimes may favor introduced species. <br />29 <br />