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analyis had interpolated cross sections every one -tenth of a mile to smooth out abrupt <br />• transitions in river geometry. <br />Each site has 3 surveyed transects, an upstream, middle and downstream transect. The <br />middle transect was inserted within the nearest cross section in the model (model cross <br />sections are spaced every one -tenth of a mile), the upstream transect was inserted into the <br />cross - section one -tenth of a mile upstream and the downstream transect was inserted in <br />the cross - section one -tenth of a mile downstream. The upstream and downstream cross <br />sections can be shifted to actual distances from the middle cross section but were left at <br />one -tenth of a mile for this analysis. The deepest point in the transect (the thalweg point) <br />was assigned the lowest elevation in the associatea cross- secuon. 111e UU11JGGl Wan, uj.-. <br />inserted into the deepest channel of the cross section with the new transect points <br />replacing the old cross section points at the locations of overlap. Matching the deepest <br />point in the channel between the new transect and the old cross section preserved the <br />measured slope values in the model. <br />Because the HECRAS cross sections include all channels in the cross section, there was <br />no need to develop a ratio for amount of flow in the whooping crane channel. <br />The HECRAS model has multiple options for data output including: cross section plots <br />showing channel boundaries, water surface, and hydraulic data such as velocity at each <br />point in the cross section; longitudinal plots showing the bed elevation, water surface and <br />energy grade lines; and user specified tables of 30 variables (average velocity, top width, <br />max. depth, friction loss, etc) for a single cross section or user specified variables for all <br />the cross sections in the model. There are 264 options for selecting variables such as flow <br />depth, flow area, average velocity, channel width and including variables for specific <br />applications i.e. ice parameters, culvert barrel flow, etc. The variables are available for <br />every cross section in the program. The main variable used for this analysis was water <br />surface elevation. Tables of data can be easily pasted into spreadsheets or input files for <br />additional analysis if the available variables are not sufficient. Wetted width (top width) <br />and average depth are standard output variables for each cross section and top width <br />variables for total, left and right channels can also be selected (when there are multiple <br />channels in a cross section). I believe widths /volumes for sand bar elevation could be <br />computed automatically using the HECRAS channel cut and fill options but haven't done <br />this in a while. Otherwise it would require separate spreadsheet or other processing <br />efforts. Computation time was 2 seconds for 8 flows (8 separate runs with 900 cross <br />sections in each run). <br />Differences between Transect Water Surfaces at Similar Sites <br />The water surface of transects surveyed at the same site on different dates could not be <br />directly compared because the values were not tied to a vertical control. Instead it was <br />assumed that the thalweg elevation of both surveys matched. Because the transects were <br />not repeated at the same location (i.e. transects beginning and ending at identical control <br />points) and might be angled differently or shifted upstream or downstream from each <br />• other; and because the thalweg or bed of a river moves up and down in response to pool — <br />Summary of Phase I Whooping Crane Data Analysis November 6, 2007 <br />4 <br />