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UUUJJJ Draft - Do Not Cite 15 August 2003 site-specific data, bed-load relationships are only as good as the associated input data, and their applicability is limited to the area associated with that information. ~ an alternative approach to performing site-specific sediment transport calculations, -X- researchers have identified flow conditions that are considered to promote habitat maintenance and improvem~t. Milhous (1998), Pitlick et al. (1999), and FWS identified half-bankfull and bankfull conditions as being important for maintaining habitat for the Colorado pikeminnow. For this study, the following values were used for half-bankfull and bankfull flows, respectively: 8,070 and 14,350 cfs, respectively (McAda 2003). The FWS and Milhous flow reCommendations are described in Sections. 2.4.1 and 2.4.2. Flows under each scenario were evaluated for their achievement of the FWS and Milhous flow thresholds. On the basis of the flow patterns for the Grand Junction gage presented in Figures 7 through 12, we determined the following: . Total number of days flow exceeded, . Mean number of days/yr flow exceeded, . Mean number of dayslyr flow exceeded (1978-1997 only), . Number of years flow exceeded, . Mean number of day-s/yr flow exceeded in exceedance years, and . Return period (years). In addition, we detennined the mean number of days/yr that flows were exceeded during the 1978-1997 period. This period was chosen because it was the period that served as the basis for the Pitlick et al. assessment that led to the FWS recommendations. 2.4.1 FWS Flow Recommendations Recently, the FWS developed flow recommendations for the Gunnison River. These recommendations focus on achieving half-bankfull and bankfull discharges at specific frequencies. (fable 2). These recommendations were largely based on the research and