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<br />" <br /> <br />. ' <br /> <br />backwaters is critical to the ecology of the river, and hence, smvival of the fishes. Temporal and <br />spatial patterns of temperature in the Green River depend upon the release level at Flaming Gorge, <br />volume, distance from the dam, ambient air temperatures, channel morphology and amelioration <br />effects by side flows, especially the Yampa. This relationship apparently can be partially controlled <br />by the selective withdrawal system at the dam, at least to Jensen. <br />These concerns are clearly problematic with respect to legitimacy of the flow <br />recommendations for the Green River. Some of my concerns may be resolved by the ongoing five- <br />year research program, although workplans I reviewed were too brief to allow judgment on that <br />issue. Moreover, integration among projects on the Green River and with recovery projects <br />elsewhere in the Upper Colorado River Basin is lacking or unclear. Research objectives ought to be <br />fairly uniform throughout the Upper Basin, given that the same fishes and ecological issues are <br />involved in all of the tributaries. <br />However, my greatest concern with recommendations for the Green River is that peak flows <br />are not very high and the baseflows are not very low and stable by predam standards (Le., the ratio <br />of peak to baseflow is 40 based on predam flows of record, whereas the recommended ratio is 12). <br />Hence, the flow recommendations may not do much ecological good, especially if the peaks do not <br />accomplish much channel reconfiguration and baseflow fluctuations for hydropower operations do <br />indeed compromise stability of the slack water food webs. <br /> <br />Colorado River <br />On the Colorado River, IFIM and a FWS flow-temperature model were used to predict July <br />- September baseflows that 1) maximized runs, riffles and pools (not backwaters) used by adult <br />squawfish and 2) increased temperatures 1 - 20C over 1978-86 obseIVed values (with the thought <br />that age-O fish would grow faster). Discharge, backwater and temperature relationships therefore <br />may be suspect, owing to the tendency of lAM to over-emphasize the importance of low flows as <br />preferred habitats. The analysis may be generally correct by default, because Kaeding and <br />Osmundson (1988) argue convincingly that the 15-mile reach is suboptimal habitat thermally. <br /> <br />59 <br />