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1 <br /> <br /> <br /> <br />1 <br /> <br /> <br /> <br />1 <br /> <br /> <br />ii <br />1 <br /> <br /> <br />1 <br /> <br /> <br /> <br />STREAM FLnW RECOMMENDATIONS <br />It ,is beyond the scope of this paper, and current technology, to produce <br />a single flow and sediment recommendation that will unequivocally protect the <br />rare and endangered fishes of the Yampa River. Although FWS and others have <br />i <br />committed substantial expenditures of time and manpower in developing and <br />applying incremental stream flow methodologies, flow recommendations produced <br />have not been validated by biological data for Colorado River rare and <br />endangered fishes. We prefer to rely on empirical data and biological <br />judgement to recommend flow regimens that are consistent with Life history <br />needs of the fish, because we are constrained by the absence of models <br />incorporating both physical and biological components, and lack of confidence <br />in physical habitat simulation models outputs. The following <br />recommendationsl are derived from preceding discussions of habitat needs and <br />limiting factors for each rare and endangered species, by time of year. <br />Colorado squawfish <br />All year: Minimum flows (for RM 0-140) should not be less than historic <br />minimums for similar hydrologic conditions. For periods not covered by other <br />recommendations, the five-year average should include a frequency of low (80% <br />exceedence), average (50% exceedence), and high (20% exceedence) flows, as <br />reflected by the historic record (1941-present). Temperature and sediment <br />transport regimens should be consistent with historic patterns. In-stream <br />structures that restrict flows and block migrations or local movements are not <br />recommended. <br />Spring: Migration cues are considered an essential component for successful <br />reproduction in this species. High spring flows approximating 3.5 times the <br />44 <br />