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Green River Colorado River 0-102 Moab bridge 0-77 Moab bridge 103-120 Green River bridge 78-94 Dewey bridge 200-244 Green River bridge 95-110 Fruita bridge 245-298 Ouray bridge 140-170 Fruita bridge 299-317 Jensen bridge Different bridges were used to calibrate various river segments to adjust for the changing elevation of the rivers. The video was acquired at 2,000 feet above mean terrain and adjustments to compensate for the changing river elevation were made at the Dewey and Jensen bridges. To calibrate the video, a frame containing each bridge was captured and saved. The ends of the bridge were delineated with an algorithm caliper. The corresponding ground measurement was then entered, and the calibrated cell length and area was calculated. At the beginning of each work session, the appropriate bridge calibration for the section of river being analyzed was loaded, and all frames were calibrated with those cell sizes. When changing to a new section of river, the next appropriate bridge with the new cell size was loaded, and all frames were calibrated accordingly. (Note: At 2,000 feet above the river, the cell size is 2 m2). Video frames were captured and a river-mile location to the nearest tenth mile was determined using the GS 7.5-minute quadrangle maps with calculated river-mile designations. Channel width was measured perpendicular to the flow of the river at the center of each frame on the video monitor using a cursor controlled by a mouse or a digitizing puck with calipers. Channel width was defined to include the distance from one bank to the other excluding vegetated islands. Channel width was measured in the center of each frame to avoid biasing the data. A total of 989 and 599 cross sections were measured on the Green and Colorado Rivers, respectively. Backwater and side channel outlines (polygons) were delineated on the video monitor. Each feature was labeled on the screen, and the corresponding measurement was saved in a text me. The channel width label format was a CW followed by the river-mile, followed by a dash, followed by the nearest tenth of a mile. The label CW033-5 indicates a channel width for river-mile 33.5. The label format for backwaters was an uppercase B followed by either a lowercase t, b, or "-" to indicate a top (upstream), bottom (downstream), or side opening on the sand or cobble bar, followed by either a lowercase b or c to indicate bank or mid-channel location, and ending with a number identifying each backwater occurring in that frame. The following types of backwaters were therefore possible: Bbb# - bottom opening bank location Btb# - top opening bank location B-b# - side opening bank location Bbc# - bottom opening channel location Btc# - top opening channel location B-c# - side opening channel location Side channels were labeled with SC followed by a number indicating each side channel occurring in that frame. A backwater or side channel label followed by a "-#" indicates that a single 3