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4 <br />associated with known fish occupation of the bar that led to limited recruitment (May <br />1984). <br />Hydrologic analyses showed that since closure of Flaming Gorge Dam base flows <br />were higher and less variable and the magnitude of peak flows was reduced. Reductions <br />in the magnitude and duration of peak flows have reduced the frequency of floodplain <br />inundation at suspected rearing areas downstream from the Green River spawning bar. <br />Water temperatures near the Green River spawning area were within an acceptable range <br />during the spawning period and probably did not directly limit reproduction during 2000. <br />Repeated surveys showed variable patterns of scour and fill at Green and Yampa River <br />cross sections including deposition of sediment in the Green River spawning area at <br />flows less than 207 m3/s. Cross section surveys suggested that lenses of sand move <br />through both study areas over a range of discharges and that patterns of fill during high <br />flow and scour during recession occur in both the main and side channels of the Green <br />River site. <br />Habitat comparisons showed that the Green River site had a proportionally larger <br />area of slow current velocity habitats over a range of flows than the Yampa River site due <br />largely to differences in the size and elevation of channel features. Availability of <br />shallow, moderate velocity habitats typical of those used by spawning razorback sucker <br />in previous studies was higher during May 2000 than in May 1984 at both study sites. <br />Conditions at spawning areas during 1984 were dominated by relatively deep and fast <br />current velocity habitats. Year 2000 telemetry data showed that fish used a range of <br />habitats during the spawning period but were often located in depths of less than 1.0 m <br />and velocities between 0.4 and 1.2 m/s. Razorback sucker use of the Green River