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• DRAFT February25, 1998 three years on the average and would provide flooding frequency and duration similar to pre-1963 conditions. The maximum possible area of inundation is about 4,050 hectares, which currently occurs for a discharge over 37,000 ft3/s (100-year event). In Canyonlands, flooding of the side canyon backwater areas initiates at a discharge of approximately 7,000 f:3/s. And increases linearly up to bankfull discharge, 39,000 ft3/s. It was estimated that 200 hectares of floodplain became inundated between 30,000 (5-year) and 53,000 ft3/s (100-year). Restoration of flooded bottomlands habitat at Ouray could be accomplished through a combination of increased water surface elevations, prolonged peak flow duration, lower bank or levee heights and constructed inlets. Construction activities to restore flooding must address channel stability issues, potential increase in flood levels, sediment deposition, and potential changes in channel morphology. In Canyonlands, enhancing the flooding of side canyon backwater areas can be accomplished only through flow augmentation. It is not practical to restore or enhance flooding through physical alteration of the backwater habitat areas. Because of the • magnitude of the required overbank flow, flow augmentation is probably impractical as well. FLO Engineering, Inc. 1997(a). 1996 Green River Discharge Monitoring. Habitat Restoration Program, Recovery Program Project #72. FLO Engineering, Inc., Breckenridge, Colorado. 18p. The results available for the 1996 monitoring of the Green River runoff indicate several key findings regarding flow routing. First, for flows in the range of 12,000 ft3/s to 18,000 W/s, the travel time from Jensen to Stillwater Canyon is approximately 85 hours and the mean velocity is about 1.1 m/s. Secondly, for flows from 5,000 ft3/s to 12,000 ft3/s, the travel time between the same two points is approximately 100 hours with a mean velocity of 0.9 m/s. Third, downstream from Jensen, the Green River is a gaining river, that is, average discharge increases with distance downstream from Jensen. Fourth, the sharp peak discharge at Jensen flattens and increases in duration with the inflows from the White and Duchesne Rivers. FLO Engineering, Inc. 1997(b). Green River Floodplain Habitat Restoration Investigation - Bureau of Land Management Sites and Ouray National Wildlife Sites near Vernal, Utah. FLO Engineering, Inc., Breckenridge, Colorado. 62p. Ten Green River study reaches containing bottomlands were selected for floodability assessment. The ten bottomland areas were located near Vernal, Utah, stretching over 40 20