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support of a channel maintenance flow recommendation for the White River near Watson, Utah", to identify the instream flow needs of endangered fishes in the White River. Our report uses habitat availability data to try to define base flow needs for endangered fishes, whereas the Schmidt and Orchard (2002) study addresses geomorphological criteria that affect channel changes, i.e., high flow needs, to maintain existing habitat. Endangered fish occupying the White River are primarily limited to the adult life stage of the Colorado pikeminnow (Pytchocheilus lucius). No humpback chub (Gila cypha) or bonytail (G. elegans) populations have been identified in the river and only a few razorback sucker (Xyrauchen texanus) or juvenile Colorado pikeminnow have been collected, most of which have been found in the lower reach of the river. Although the current hydrograph is similar to the historic flow, approximately 30% of the upstream habitat available to Colorado pikeminnow has been reduced by the main-channel barrier, Taylor Draw Dam, near Rangely, Colorado. Despite the reduction in range, the highest catch rates of adult Colorado pikeminnow in the upper Colorado River basin have been recorded in the White River (McAda et al. 1994, 1998,2002). Preliminary population estimates suggest that the density of Colorado pikeminnow in the White River are two to three times the density of Colorado pikeminnow in the Yampa River (Bestgen et aI.2002). Thus, the White River represents a significant factor in the recovery of Colorado pikeminnow in the upper Colorado River basin. The purpose of this report waS to identify the base flow needs of endangered fish, i.e., adult Colorado pikeminnow, in the White River. The scope of work outlined three objectives: 1. Detennme meso- and microhabitat availability for adult Colorado pikeminnow during three low flow scenarios. 2