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Habitat vs Discharge Study As in 1982, high water limited our capability to complete all phases of the work scheduled for this year. The absence of young Colorado squawfish in the system prohibited the completion of the biological part of the program. However, three study sites were chosen to evaluate physical habitat changes from 22 Oct. to 4 Nov. as the discharge from Flaming Gorge Reservoir was manipulated. Each site was selected to represent a variety of riverine habitats between Split Mountain and Desolation Canyons. The Locations were RK 504 (RM 315) in Dinosaur National Monument (DNM), RK 465 (RM 291) just below the new Bonanza highway bridge, and RK 400 (RM 250) about two miles above the Ou ray br idge. The site at RK 504 ' consisted of a well defined rocky side channel at high flows and a backwater and isolated pool in low flows. The site at RK 465 was a wide shallow sandy area with numerous sand bars and small backwaters at both high and low flow. The site at RK 400 consisted of a high runoff side channel, a permanent island and a large eddy which developed into a heavily-silted backwater at lower flows. Water discharge from Flaming Gorge Dam was regulated to provide a Low flow of 800 cfs and a high flow of 4,000 cfs. These flows represented the lowest and highest flows anticipated during the September-October period under study. Low flow was released at 0800 h on 22 October and maintained until 0800 h on 24 October when the high flow was provided. This sequence was repeated on 29 October to 31 October and the normal release schedule was resumed at 0800 on 2 November. Staff gauges were set at each site and the water levels were checked every six hours from 23 October through 4 November. Depth measurements were taken across the main channels at both 800 and 4000 cfs. During the second rotation at both high and low flows, the site boundaries wer e staked with white bags so they would be visible from the air. A photo- grapher from the Bureau of Reclamation (BR) took aerial oblique photo- g raphs at each site on 31 October and 3 November to record approximate changes in selected habitats at high and low flows. The change in the habitats of the selected sites with different flows was similar between rotations at the DNM and Ouray sites. The site at the Bonanza bridge, however, was markedly different due to scouring of the shallow sandy area at high flows. At lower flows, the side channel at the DNM site was dewatered and a backwater and small. isolated pool formed on its downstream end. At higher flows, the side channel was well established and the isolated pool became a backwater. The habitat at the Bonanza bridge site was dominated by a sand bar along the left bank just below the bridge with the main channel along its right bank. At high flows, the sand bar formed an island with a shallow, sandy side channel along its Left bank. At low flows the side channel closed off, forming backwaters at both the upper and lower ends. The right side of the island formed two backwaters. The Ouray site consisted of an island in the main channel and a large shoreline eddy along the bend of 27: