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and 0.7 and 1.1 feet, respectively (Appendix; Table G.1.). If Colorado squawfish require 2 feet for passage rather than 1 foot, a flow of 1,600 cfs would be required at transect 9 (Appendix; Figure G.4.). Similarly, 900-1,000 cfs would be required at transect 19 to provide a maximum water depth of 2 feet (Appendix; Figure G.5.). There was a discrepancy at transect 20 between the empirical and predicted water depths. Ninety-nine water depth observations were recorded at FWS transect 20 during July. The mean and maximum water depth was 0.6- and 1 foot, respectively, at 266 cfs. On the other hand, the BR transect predicted a mean and maximum water depth of 3.2 and 7.3 feet, respectively, at 300 cfs. One explanation is that the location and orientation of the BR and FWS transect to the channel did not exactly correspond. Immediately up- and downstream of transect 9 and 19, the water column is deeper. At transect 8, immediately upstream of transect 9, the mean and maximum water depth was 1.3 and 2.3 feet, respectively, at 300 cfs (Appendix; Table G.1.). At transect 10, immediately downstream, the mean and maximum water depth was 1.9 and 2.8 feet, respectively, at 300 cfs. At transect 18, immediately upstream of transect 19, at 300 cfs the mean and maximum water depth was 6.9 and 11.0 feet, respectively. At transect 20, the predicted mean and maximum water depth was 3.2 and 7.3 feet, respectively. These data indicate that adequate water depths for passage up- and downstream of these three critical shallow areas were available at 300 cfs. The HEC-2 model predicted that water depths greater than 1 foot were exceeded at only one location each at transects 4, 9, and 19. The model predicted that water depths greater than 1 foot up- and downstream of these three critical shallow areas were exceeded at least at three locations at each of the 24 other transects in the reach at 300 cfs; the predicted mean depth for the entire reach at 300 cfs was 2.7 feet (Appendix-, Tables G.2. and G.1.). The high number of adult Colorado squawfish found in the reach during late July and early August 1994 indicates that sufficient habitat is available for "residency" at 300 cfs. The areas up- and downstream of these shallow-water areas are pools that provide suitable habitat for fish to "hole up" for short periods during low flows. Successive pool/riffle habitat combinations occur in the 2.3-mile reach during low flows. These pools are deeper than riffles and are maintained by cobble bars at the downstream end that serve as hydraulic controls to dam the water. Water depths predicted by the HEC-2 model differed slightly from the empirical values. One possible explanation was that during the high runoff period in 1993, the stream bed may have scoured at cross sections surveyed. The BR field transect work was conducted in April prior to runoff, whereas the FWS field transects were conducted during July and August of the same year, following runoff. Consequently, the invert of the channel could have been altered following runoff. Also, the BR transects were surveyed in April when flows ranged from 2,700 to 4,100 cfs. Because the transect work was conducted during mid-flow conditions, the HEC-2 model predicted water depths greater than actually existed for low-flow periods; conversely the model predicted water depths less than actually existed during high flows. Ideally, the transects should have been conducted during a lower flow period to increase the accuracy of the model for the flows of interest (e.g, 300-1,000 cfs). Despite the slight differences between water depths for the two methods, water depths predicted by the HEC-2 Ii model were comparable to the actual or empirical water depths for transects at 26