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<br />14 <br /> <br />The average size of all backwaters at the Ouray site was much larger than at <br />Island Park and Jensen, ranging from 417 m2 at 1,381 ft3;s to 831 m2 at <br />1,773 ft3;s. Backwaters per mile ranged from 3.9 at 5,260 ft3;s to 6.6 at <br />1,381 ft3;s, somewhat less than Island Park and Jensen. Backwater area per <br />mile at Ouray was the most of any site, ranging from 1,678 m2 at 5,260 ft3/s <br />to 4,697 m2 at 1,687 ft3;s. <br /> <br />Sand Wash <br /> <br />The area for interpreted classes for each flow at Sand Wash are presented in <br />table 10. The lowest backwater area at the Sand Wash site occurred at <br />5,260 ft3/s (4,962 m2) (table 11). Backwater area increased 7 <br />8,466 m2 at 2,423 ft3;s, and increased again (32 percent) at 1,773 ft; <br />where it was maximized at 11,147 m2. Backwater area decrease w at at <br />1,687 ft3/s, decreased substantially at 1,430 ft3;s to 5,713 m2, and then <br />increased again (92 percent) at 1,381 ft3/s. The low backwater area at <br />1,430 ft3;s was an anomaly and examination of flow data indicated that <br />riverflow was actually lower at this time than at any other flow. The <br />1,430 ft3;s flow was maintained for one day at the Jensen gauge and had not <br />reached the Sand Wash site when the photogra~hy was acquired. The actual <br />flow was probably less than that at 1,101 ft Is. Backwater formation at <br />1,430 ft3;s was further complicated by the chronology of flows as previously <br />discussed. <br /> <br /> <br />The flow at Sand Wash was difficult to determine because the White and <br />Duchesne Rivers enter the Green River between Sand Wash and the Jensen <br />gauge. Furthermore, the Price River enters the Green River between the Sand <br />Wash site and the Green River gauge which would cause the Green River gauge <br />readings to be higher than the flow at Sand Wash. Despite these facts, it <br />was still apparent that backwater area at the Sand Wash site was maximized <br />at flows below 2,423 ft3;s as measured at the Jensen gauge. <br /> <br />The total number of backwaters ranged from 11, at 1,430 and 1,101 ft3;s, to <br />22 at 5,260 ft3/s (table 10). Sand Wash site was unique because backwater <br />~r was maximized at the highest flow. Furthermore, backwater numbers <br />were much more evenly distributed among the various size classes than at the <br />upper sites. Backwaters per mile ranged from 2.9 at 1,430 and 1,101 ft3;s <br />to 5.8 at 5,260 ft3;s, the lowest of the upper four sites. Backwater area <br />per mile ranged from 1,306 m2 at 5,260 ft3/s to 2,933 m2 at 1,773 ft3/s. <br />Average backwater size ranged from 226 m2 at 5,260 ft3;s to 906 m2 at <br />1,381 ft3/s. Generally, the Sand Wash site had substantially f~war c, NO-\- 1j "'''-c\.... <br />backwaters and ress backwater area per mile than the three upper sitp~) <br />There were usually more bank than channel backwaters, and bacKwaters were <br />relatively evenly distributed among size classes. <br /> <br />Mineral Bottom <br /> <br />The area for interpreted classes at each flow for Mineral Bottom are <br />p in table 12. Backwater area at Mineral Bottom was maximized at <br />3,261 ft s at the USGS Green River gauge (Jensen gauge was 2,423 ft3;s)--. <br />Wl ,24 m2 (table 13). Backwater numbers were also maximized at S:2..U <"'+-r <br />