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<br />,
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<br />
<br />maximized at 1381 cfs, the >500m2<1000m2 was maximized at 1773 cfs, and
<br />the >1000m2 class was maximized at 1101 cfs.
<br />
<br />Island Park, Jensen, and Ouray Totals
<br />
<br />There are no major tributaries to the Green River between the Island
<br />Park, Jensen, and Ouray sites. Therefore, these were also considered as
<br />a single unit for backwater analyses. Table 7 (Appendix A) presents the
<br />backwater number, size distribution, area, and average backwater size
<br />for each flow tor Island Park, Jensen, and Ouray sites inclusively.
<br />Backwater area was maximized at 1,101 cfs with 82,368 m2 (20.4 ac).
<br />There was a significant increase in backwater area from 5,260 cfs to
<br />2,423 cfs (34,323 m2 to 57,625 m2) and from 2,423 cfs to 1,773 cfs
<br />(57,625 m2 to 71,956 m2). All flows at 1,773 cts and lower had
<br />significantly more backwater area than the 5,260 and 2,423 cfs flows.
<br />
<br />Backwater number was maximized at 1,381 cfs (176). Once again, however,
<br />the 1,773 cfs and lower flows had significantly more backwaters than the
<br />5,260 and 2,423 cfs flows which had 115 and 130 backwaters,
<br />respectively. The >20m2<200m2 size class contained the most backwaters,
<br />followed by the >200m2<500m2 and <20m2 size classes. Except at 5,260
<br />and 2,423 cfs there were more bank-backwaters than channel-backwaters.
<br />The average size of all backwaters ranged from 298 m2 at 5,260 cfs to
<br />508 m2 at 1,101 cfs.
<br />
<br />Figure 11 (Appendix A) presents backwater area (m2) versus flow (cfs).
<br />Bank-backwater size was maximized at 1101 cfs, channel-backwater size
<br />was maximized at 2423 cfs and total backwater size was maximized at 1101
<br />cfs. Figure 12 (Appendix A) presents numbers of backwaters versus flow
<br />(cfs). Bank-backwater numbers were maximized at 1101 cfs,
<br />channel-backwater numbers were maximized at 1687 cfs, and total
<br />backwater numbers were maximized at 1381 cfs. Figure 13 (Appendix A)
<br />presents backwater size distribution versus flow (cfs). The <20m2 size
<br />class was maximized at 1381 cfs, the >20m2<200m2 size class was
<br />maximized at 1381 cfs, the >200m2<5002 size class was maximized at 1430
<br />cfs and 1381 cfs, the >500m2<1000m2 was maximized at 1101 cfs, and the
<br />>1000m2 class was maximized at 1381 cfs.
<br />
<br />Sand Wash
<br />
<br />Table 8 (Appendix A) presents the area of each class for each flow at
<br />the Sand Wash Site. The lowest backwater area occurred at 5,260 cfs [
<br />4,962 m2 (1.2 ac) ]. Backwater area increased 71% to 8,466 m2 (2.1 ac)
<br />at 2,423 cfs, and increased again (32%) at 1,773 cfs where it was
<br />maximized at 11,147 m2 (2.8 ac). Backwater area decreased somewhat at
<br />1,687 cfs, decreased substantially at 1,430 cfs to 5,714 m2 (1.4 ac),
<br />and then increased again (92%) at 1,381 cfs. The low backwater area at
<br />1,430 cfs was an anomoly and examination of the open water class area
<br />indicates that river flow was actually lower at this point than at any
<br />other flow. The 1,430 flow was maintained for one day at the Jensen
<br />gauge and we do not believe this flow had reached the Sand Wash site
<br />when the photography was acquired. The actual flow was probably less
<br />than that at 1,101 cfs. Backwater formation at 1,430 cfs was further
<br />complicated by the chronology of flows as previously discussed.
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