|
<br />1,687 cfs did not occur at lower flows, therefore, backwater area
<br />was much lower at these flows. The average size of all backwaters
<br />at the Ouray site2was much larger than aZ Island Park and Jensen,
<br />ranging from 417 m at 1,381 cfs to 831 m at 1,773 cfs. Backwaters
<br />per mile ranged from 3.9 at 5,260 cfs to 6.6 at 1,381 cfs, somehwat
<br />less than Island Park and Jensen. Backwater area2per mile at Ouray
<br />was the2 most of any site, ranging from 1,678 m at 5,260 cfs to
<br />4,697 m at 1,687 cfs.
<br />
<br />Sand Wash
<br />
<br />Table 7 (Appendix A) presents the area of each class for each flow
<br />at the Sand W2sh Site. The lowest backwater area occurred at 5,262
<br />cfs [ 4,962 m (1.2 ac)]. Backwater area increased 71% to 8,466 m
<br />(2.1 ac) at 2,423 cfs, and in~reased again (32%) at 1,773 cfs where
<br />it was maximized at 11,147 m (2.8 ac). Backwater area decreased
<br />somewha~ at 1,687 cfs, decreased sUbstantially at 1,430 cfs to
<br />5,713 m (1.4 ac), and then increased again (92%) at 1,381 cfs. The
<br />low backwater area at 1,430 cfs was an anomoly and examination of
<br />the open water class area indicates that river flow was actually
<br />lower at this point than at any other flow. The 1,430 flow was
<br />maintained for one day at the Jensen gauge and we do not believe
<br />this flow had reached the Sand Wash site when the photography was
<br />acquired. The actual flow was probably less than that at 1,101
<br />cfs. Backwater formation at 1,430 cfs was further complicated by
<br />the chronology of flows as previously discussed.
<br />
<br />The flow at Sand Wash was difficult to determine because the White
<br />and Duchesne Rivers enter the Green River between Sand Wash and the
<br />Jensen gauge. Furthermore, the Price River enters the Green River
<br />between the Sand Wash site and the Green River gauge which would
<br />cause the Green River gauge readings to be higher than the flow at
<br />Sand Wash. Given these facts, it is still apparent that backwater
<br />area at the Sand Wash site was maximized at flows below 2,423 cfs
<br />as measured at the Jensen gauge.
<br />
<br />Table 8 (Appendix A) presents the backwater number, size
<br />distribution, area, and average size of backwaters for each flow at
<br />the Sand Wash site. The total number of all backwaters ranged from
<br />11, at 1,430 and 1,101 cfs, to 22 at 5,260 cfs. The Sand Wash site
<br />was unique because backwater number was maximized at the highest
<br />flow. Furthermore, backwater numbers were much more evenly
<br />distributed among the various size classes than at the upper sites.
<br />Backwaters per mile ranged from 2.9 at 1,430 and 1,101 cfs to 5.8
<br />at 5,260 cfs, the 12west of the upper four siZes. Backwater area
<br />ranged from 1,306 m at 5,260 cfs to 2,933 m at 1,773 cfs. The
<br />average backwater size ranged from re~atively small at 5,260 (226
<br />M) to quite large at 1,381 cfs (906 m ). Generally, the Sand Wash
<br />
|