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. . . . " -~ 25 reservoirs depress peak runoff flows from April through mid-July by storing water during those months. The water is then redistributed and released during other months, depending on demand and/or operating criteria for the reservoir. Additional flows in November, December, January, and February can be attributed to releases made for power production, flood control, and maintenance of instream flow. During April, May, and June the reservoirs are storing water, and agricultural diversions which typically operate from April through October are also depleting water. Agriculture, coupled with increased municipal demands, accounts for the majority of reductions evident in July, August, September, and October. Flow reductions from the existing condition scenario to the environmental baseline are attributable to depletions related to water projects that have undergone successful Section 7 consultation but are not yet on-line (Table 8). Many of these projects involved the consumptive use of water by industry, which have demand patterns that remain fairly constant year-round. Large industrial demand, unencumbered by senior agriculture water rights which are not in use in the winter months, are responsible for the reduced flows exhibited for all months of the environmental baseline simulation. IMPACT ANALYSIS The Instream Flow Incremental Methodology (Flow Methodology) (Bovee, 1982) was used to quantify the flow needs of Colorado squawfish in the IS-mile reach of the Colorado River between Palisade, Colorado, and the confluence with the Gunnison River. A Flow Methodology site was selected in 1985, at RM 181.4- 182.0. Careful attention was given to selecting a site with representative geomorphological conditions; the site also contained a good diversity of habitat for Colorado squawfish. Habitat types represented at the site include pools and eddies, cobble bars/riffles, and backwaters. Field measurements were taken at flows ranging from 1,600 to 7,600 in 1985 and 1986. Simulation was accomplished using a combined WSP/IFG-4 modeling technique described by Milhous et al. (1984). Habitat utilization curves for Colorado squawfish nonspawning adults (Fish and Wildlife Service 1984) and spawning/egg deposition were used in the simulation (Spawning/egg deposition curves developed by L. Kaeding and C. McAda in April 1987). Habitat-utilization curves for adults were based on observations of adult Colorado squawfish throughout the basin during the spring, summer, and fall of the year. This analysis assumes that these data also reflect the habitat preference of Colorado squawfish during the winter. This assumption is supported by radiotelemetry studies which were conducted in the IS-mile reach in 1986-87. The resulting habitat versus flow curves are shown in Figure 2. Figure 2 indicates that habitat for adult Colorado squawfish and egg deposition (spawning) habitat are both maximized at 2,000 cfs. A more detailed description of the site, field measurements, habitat utilization curves, and results of the simulation are contained in Appendix A.