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enhance populations of the four endangered fishes. The specific objectives were developed to create and maintain the variety of habitats used by all life stages of the four endangered fishes: • Provide habitats and conditions that enhance gonad maturation and provide environmental cues for spawning movements and reproduction; • Form low-velocity habitats for adult staging, feeding, and resting areas during snowmelt runoff; Inundate floodplains and other off-channel habitats at the appropriate time and for an adequate duration to provide warm, food-rich environments for fish growth and conditioning, and to provide river-floodplain connections for restoration of ecosystem processes; • Restore and maintain in-channel habitats used by all life stages: (1) spawning areas for adults, (2) spring, summer, autumn and winter habitats used by subadults and adults, and (3) nursery areas used by larvae, YOY, and juveniles; and • Provide base flows that promote growth and survival of young fish during summer, autumn, and winter: Because historical. river flows were dependent on water availability, flow recommendations were developed for six hydrologic categories that correspond to unregulated April-July inflow based on the 1937-1997 period of record: Dry (90-100% exceedance); Moderately Dry (70-90% exceedance); Average Dry (50-70% exceedance); Average Wet x-(30-50%v exceedance); Moderately Wet (10-30% exceedance); and Wet (0-10% exceedance).. Flow recommendations are for the Gunnison River at the USGS river gage near Grand Junction, Colorado (09152500) and for the Colorado River at the USGS river gage near the Colorado-Utah state line (09163500). Spring peak-flow recommendations for both rivers correspond to specific recommendations by Pitlick et al. (1999) to maintain and improve in- channel habitat in both rivers. Peak-flow recommendations include two components: (1) threshold levels corresponding to 'h bankfull discharge and bankfull discharge and (2) the number of days (duration) that flows should equal or exceed these levels. In addition, recommended durations are presented as a range of days to provide flexibility to river managers. In general, spring flows recommended for the dry categories provide small peaks used as spawning cues by endangered fish, but contribute little to habitat maintenance; spring flows recommended for average categories promote scouring of cobble and gravel bars and provide localized flooding of short duration; and spring flows for the wet categories promote wide-spread scouring of cobble and gravel bars, flushing of side channels, removal of encroaching vegetation, and inundation of floodplain habitats. Base-flow recommendations also vary with hydrologic category and are designed to allow fish movement among river segments and to provide maximum amounts of warm, quiet-water habitats to enhance growth and survival of young endangered fish.