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. 1'- ""''''_''<'7,,,,~'A.'9;_-..._, 19 Table 17. Photography - videography cost comparisons. Cost component CIR aerial photography Airborne videography Data acquisition $5,600 Field work (2 staff weeks) 4,000 Image interpretation 3,000 Map preparation 2,000 Digitization 2,000 Computer costs 400 Plotting 400 Report 1,000 $1,600 4,000 3,000 o o o o 1,000 Totals $18,400 $9,600 Cost for data acquisition was based on 21 rm; interpretation cost was based on 6 rm. The total cost for aerial photography/GIS was approximately twice that of airborne videography/MIPS. The costs for image interpretation of videography may be reduced significantly as image analysts become more familiar with videography images and the computer software used. DISCUSSION 1986 Pilot Study The 1986 pilot study indicated that 1:4,000 scale color infrared aerial photography could be successfully used to determine backwater availability on the Green River. Analysis of the two 1,889 ft3/s flows photographed at different times produced some interesting observations. The Qftober Flaming Gorge Dam r~l eases averaQed 2.700 ft3/ s /i tb a ~ flow of !, 240 ft3/ s ~ and the Novemb~r releases !yeragpd 3,800 ft /s with a hlgh flow ~f 4.180 ft Is. Apparentl flows of this ma nitude were sufficient 0 dis lace and de rade s~s. These 1 w even . e ed total bac water area b t ~err.p-nt although total backwaters decreaseg. 1987 Study Optimum flows for maximizing Green River backwater habitat varied among sites. However, the data indicated a range of flows which produced maximal backwater area and numbers under the conditions of the study. When the four upper sites are considered, a range of flows from 1,101 to 1,773 ft3/s produced substantially more backwater area and numbers than did 5,260 and 2,423 ft3/s flows. The Island Park and Jensen sites had predictably more backwater area as flows were decreased, and backwater area was maximized at a range of 1,101 to about 1,430 ft3/s. The large increase in backwater area