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resource reports, and translates the AMWG's management objectives into research needs for the GCMRC. The GCMRC conducts the research and monitoring necessary to evaluate operations and the Science Advisory Board (which has yet to be formed) will provide outside review and credibility. b. Habitat Maintenance Flow Fall 1997 inflows to Lake Powell were above normal as the result of high precipitation throughout much of the Colorado River Basin. Possibly an effect of the strong EI Nino anomaly, this precipitation created several short duration flood events on the Paria River, a tributary to the Colorado River just downstream from Lees Ferry. These floods brought an unusually large amount of fine sediment from the Paria drainage into the Colorado River. Researchers felt that this sediment would be quickly transported downstream and desired to carry out some type of high release from the dam in order to move the sediment from the main channel into eddies and channel margins where less sediment would be transported downstream. Since there were no hydrologic or dam safety reasons to release another beach/habitat-building flow as in March 1996, a release at powerplant capacity was scheduled as a type of test of the habitat maintenance flow described in the Glen Canyon Dam final EIS (habitat maintenance flows are high releases within powerplant capacity while beach/habitat-building flows are high releases that exceed powerplant capacity). On November 4-5, 1997, a 48-hour release at powerplant capacity (3,600 cfs at that time) was made. The average daily releases before and after the release were about 21,000 cfs; thus, the test flow increased the river discharge by about 10,000 cfs, a 45 percent increase. The river stage increased between about 1 .5 to 3 feet depending on the location in the Grand Canyon. Preliminary results indicate that maximum powerplant flows can be used to rebuild low-lying sandbar platforms and result in little disruption of terrestrial endangered species. However, a flow of this magnitude is probably insufficient to create or substantially rejuvenate backwater habitats which serve as nursery habitats for native and non-native fish. Although some sandbars increased in area and volume, this flow may not have been of sufficient duration to maximize sandbar rebuilding. c. Glen Canyon Dam Temperature Modification Project The Fish and Wildlife Service and Reclamation believe that the cold summer temperatures in the Colorado River, created by releases drawn from deep in Lake Powell, are a constraint to the recruiting and spawning of native and endangered warm-water fish in the river. The biological opinion issued by the Fish and Wildlife Service on the preferred alternative of the Glen Canyon Dam EIS included a requirement to consider increasing the temperature of releases through selective withdrawal. The draft temperature modification project environmental assessment will propose a 515 million modification to the penstock intakes at the dam that would allow summer temperatures to be raised from 46°F to 59°F. This would not only benefit the endangered fish, but should also provide optimum temperatures for the trout fishery located immediately below the dam. The draft environmental assessment will be released in January 1999. 34