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~ I I I I ! ! ! J j I I ( \ I I I Water velocities measured in the structure ranged from .0.5 to 2.5 mls with a mean of 1.4 mls. Maximum velocity was recorded in the center of the chute between the first and second stationary waves (location #12, Figure 2). Other areas of high velocity were observed at the base of both walls. Eddy currents or areas of very low velocity were detected along the edge of the chute (locations #7, 10, 13, 16 and 17). Low velocities were also recorded in the center of the chute below the second stationary wave, probably associated with the disruption of flow created by the wave. DISCUSSION Mark and recapture data collected during this investigation indicate that a majority (84%) of the fISh in the study area moved at least 0.1 miles. Of the fish that moved, it appears that fish may have exhibited a slight tendency for upstream movement although increased sampling above the structure undoubtedly biased the data. Mean net movements also suggested an upstream movement pattern for six of seven species that were tagged and recaptured during the study. Of the fISh that passed the structure in either an upstream or downstream direction, a similar pattern of movement was exhibited such that 74% of the fISh passed the structure in an upstream direction. The consistency in movement patterns of fish in the study area as a whole with the movement patterns of fish passing the diversion structure suggest that the structure did not impede overall movements of fish in the study area within the range of flows observed. Observations of movements of recaptured northern pike and flannelmouth sucker (Colorado squawfish surrogates) were generally consistent with patterns observed in other fish species. Movements by both of these species were approximately evenly distributed in an upstream and downstream direction, with relatively few fISh exhibiting no movement. Numbers of fish passing the structure showed a similar pattern with four fISh passing the structure moving upstream and four fish passing downstream. Relationship between flow and fish passage over the structure was difficult to assess during one year of study. Passage over the structure in an upstream direction was observed during or between all sampling trips although more passage was observed in the spring between April and June and in the fall between September and October than during the summer period between June and September. These differences may reflect normal seasonal movements associated with spawning or habitat changes. BIO/WEST found no evidence that fish passage over the structure was impeded by any flow observed during this study. Radiotelemetry data collected during this investigation provided documentation of three northern pike passing the diversion structure, one in both a downstream and upstream direction and two in an upstream direction. Although this was further documentation of the surrogate's ability to move past the structure, all movements occurred during relatively high flows. Migration of these three fish and other radiotagged fISh to locations significantly removed from the diversion structure precluded additional data collection relative to fish passage at lower flows. Failure to maintain contact with any of the eight radio tagged native fish during the investigation suggests that future studies of this nature involving radiotelemetry should include a more intensive tracking effort to maintain contact with radiotagged fish. Physical habitat measurements and observations of conditions in the structure suggest that fish passage would not be impeded under any of the flows observed during the study. Although depth 25