6008 - Laserfiche WebLink

Home Browse Search

the river. A small outlet drained a flooded river bottom located to the east. At low flows, a backwater was created by the eddy and water from the river bottom was discharged near the upper end of that eddy. At high flows, the eddy current from the main channel flowed into the lower end of the backwater forming two small islands. When flows stabilized at 800 and 4000 cfs, major habitats at each site were staked and measured. Fish population changes were studied by seining these various habitats in relation to the varying river flows. No major difference was observed between the numbers of fish collected at the DNM and Bonanza sites at both high and low flows. At the Ouray site, the number of fish collected increased as the flow in the river decreased. Colorado squawfish were not collected at any location which conf irmed the findings of our YOY monitoring program since we expected YOY Colorado squawfish to seek their preferred backwater habitats. Fish data are preliminary at this time. Fish species and habitat associations at different flows will be further compared to YOY monitoring data and the 1984 habitat study. The results of these data comparisons will be provided in the final report. There was an approximate lag-time of 24 hours in water delivery from Flaming Gorge Dam to the Bonanza site for the 4000 cfs discharge, and a 52 hour lag-time to the Ouray site. This Iag time was far shorter than predicted by BR hydrologists during the 1980 peaking power exercise and the water level fluctuation was also greater than predicted with a change of water level between high and low flows as great at 1.79 ft (0.6 m) at DNM, 2.12 ft (0.9 m) at Bonanza ,and 1.94 ft (0.6 m) at Ouray. This water level change was rather constant with little dampening effect noted. 28