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<br />14 <br /> <br />Multiple Transect (R-2 Cross) Method <br /> <br />The minimum number of calibration flows (field discharge <br />measurement) used was one and the minimum number of cross sections <br />was two (Table 5), When only one calibration flow was used in the <br />analysis, it was generally because the other calibration flows were <br />too high or too low to be of any use in the analysis process, i.e., <br />percent wetted perimeter, average depth, and average velocity at <br />that particular flow never met the minimum levels established as <br />the limiting factors. In all study areas at least one transect of <br />three types of stream habitat (riffles, runs, pools) were selected <br />to be included in the Multiple R-2 Cross Transect analysis. The <br />reader is referred to Stalnaker and Arnette (1976) for concise <br />definitions of these terms. Additional terms were added to more <br />fully describe the particular stream transect being evaluated. <br /> <br />These transects were selected because they were considered <br />representative of the actual stream configuration in the area being <br />evaluated. Each transect was analyzed according to [he criteria <br />set forth in Table 3 for the "critical riff1~' study transects <br />together with the modifications in the criteria for run and pool <br />habitats as set forth in Table 3-A. <br /> <br />Once the average velocities, average depths, percent wetted <br />perimeters, and recommendations for instream flows were made for <br />individual transects within a stream reach, the simple average <br />was taken for each parameter, and the average recommended flow in <br />cfs was used as the minimum flow for the Multiple Transect R-2 <br />Cross analysis process (Table 5). <br /> <br />For each transect analyzed, the parameters that first became <br />limiting by falling below the minimum criteria are underlined in <br />Table 5. In 50 out of 77 instances or 65% of the time average depth <br />became the limiting factor first. Average velocity became limiting <br />or co-limiting 13 times or 17% of the time and percent wetted perim- <br />eter became limiting or co-limiting 14 times or 18% of the time. <br /> <br />The recommended flows developed using this multiple transect <br />,analysis were verv similar to the flows obtained using the single <br />transect method. These results indicate that the extra time ex- <br />yended on the multiple transect method is probably not worthwhile <br />pince there is no greater resolution or refinement in the minimum <br />,flow recommendation. The only advantage might be that the water <br />courts may consider the recommendation more reliable since it was <br />based on several different cross-sections over several types of <br />stream habitat. <br />