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Draft Final Completion Report [0 UDWR for Contract #93-1070, Amendment 3 23 Cross-section surveys were conducted once in 1992 and five times in 1993 (Table 2): at peak flow, twice on the descending limb and at base flow conditions (Fig. 10). Cross section surveys conducted in November, 1992, were assumed to represent channel conditions prior to the passage of the 1993 flood. While a complete survey was not conducted May 21. 1993, the water surface elevation and maximum depth of scour were measured. The cross sections were surveyed on seven occasions in 1994 (Table 2). Surveys were conducted prior [0 the spring flood. then every 2 weeks during flood passage (Fig.10). Each cross section was monumented by pairs of rebars and fenceposts. A wire cable, marked at 3.05 m (lO-ft) intervals, was stretched taut across the river using fenceposts for support. Cross sections were surveyed using a laser theodolite for all portions less than about 1 m in water depth. Points were surveyed at aU breaks in slope and edges of water, and points were not separated by more than 6 In. Deeper portions of each cross section were surveyed using a motorized raft and recording de.pth -sounder. Six passes were made at each cross section, and the traCe marked at 3.05 m . intervals. The trace from the depth sounder was read, values averaged. and the depth of the transducer added. The channel data were then integrated with the survey data using water-surface measurements to adjust trace depths and surveyed locations of cable marks to adjust the lateral position of trace marks. In addition. all rebars were surveyed from a single point allowing the translation of the individual cross sections into a single coordinate system. A stage-discharge relationship was develOped for the study site using water surface measurements made during the cross-section surveys and mean daily discharge data from the Jensen. Utah. USGS gaging station (Fig. 11), One day of travel time was estimated for water to pass from Jensen. Utah. to Ouray NWR. ill Cross-Section Analysis Cross-section surveys were analyzed in several ways including the following: 1) Each water year's cross sections were compared to discern the response of the channel to the passage of the snowmelt flood; and, 2) The lateral extent of the channel, thalweg. and bar were delimited by eye for each cross section. A FORmAN program was written to calculate the average elevation of the whole channel, thalweg and bar for each cross section (see Appendix A). These calculations are used to assess aggradation and erosion on the cross section at study reach scales.