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floods. Cross Sections Eleven channel cross-sections were established in the study reach near the Watson gage in May 1995, and 3 additional cross-sections were established in April 1997. Cross-sections were used to characterize channel geometry; we also identified bed material at each side. Cross-sections were spaced approximately one channel width apart, and were oriented perpendicular to the flow. Cross-section endpoints were monumented with either rebar or fence posts which were pounded to depths such that about 10-cm were exposed above ground surface. Transects were measured by attaching a length-calibrated Kevlar tag-line to the endpoints. A geodetic total station was used to measure ground-surface elevations under the tag line as well as to measure water-surface elevation and elevations of geomorphic surfaces near the channel. Elevation of cross-section endpoints were all surveyed to a common reference datum. Elevation of the bed was measured either using the total station and a rodman wading under the tagline, or was measured from a cataraft equipped with a paper-trace echo sounder and outboard motor. When measuring the bed from a raft, the boat operator maintained the boat carefully under the tag-line while slowly crossing the river. A second individual in the raft measured depth and tag-line position using the echo sounder at the marked locations along the tag-line. Measurements made from the raft were duplicated at least 4 times. Where wading was feasible, bathymetric . measurements made from the raft were also surveyed with the total station to verify the accuracy of the echo-sounder. Echo-sounder measurements concurred with total station 12