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· A mark is made on the trace for each 10-ft. mark on the tag line · The tag line is tied into the survey by surveying the end points of the depth-sounder trace. The traces are later read, and the data from the four passes averaged. The standard deviation of the four values is calculated to determine the error of the measurements. The average depths are then converted to elevations by subtracting them from the water surface elevations for the cross-sections. These elevations are then plotted against distance from the left bench mark, as shown. in FIGURES 6 - 8 and in appendices Band D. Topographic Mapping Topographic maps have been made of the bar complexes in each study reach. The mapping procedure used is the following: 1. Using the total station, a point of known elevation is established, relative to the bench marks on the bar to be mapped. 2. Anchor points such as local elevation extremes, water's edge, breaks in slope and end points of features are surveyed. 3. The points are flagged and numbered to aid in drawing contour lines. 4. All points are plotted, including cross-section data, on 10 X 1 gridded mylar. 5. The contour lines are drawn on site, in agreement with existing topography. 6. Hydrologic and geomorphic characteristics such as eddies, backwaters, bedform migration directions, substrate types, habitat quality and slip faces are drawn. on an overly. Digitizing The field-prepared topographic maps of the study reach are digitized into a geo- referenced UNIX based system with ARC. This is accomplished by hand tracing the contours on a digitizing table and then labeling the elevation values for each line. The actual bench mark coordinates are also entered and the true map scale 10