8106

• UCREFRP Catalog Number: 8106
• Author: Anderson, R. M.
• Title: Riverine Fish-Flow Investigations.
• USFW Year: 1998.
• USFW - Doc Type: Fort Collins, Colorado.
• Copyright Material: NO

differed. For riffles the mean inflection point width of 164 ft is only a 47% wetted

perimeter. The wetted perimeter variable was 52% (170 ft) for runs, and was 72% for

pools (166 ft). The larger percent wetted perimeter for pools is a result ofa smaller

channel width compared to riffles and runs.

Figure 2 in Appendix I plots the variability of stream width within habitats (the

coefficient of variation (C.v.)) versus flow. Pools were the most uniform habitat in

regard to variability of stream width between 1 and 500 cfs and the pool C. V. never

exceeded 18%. For both runs and riffle, C.v. dramatically increased as flow is lowered,

but at flows over 200 cfs, stream width becomes more uniform. The maximum c.v. on

runs was 65% at 1 cfs and 77% for riffles at 1 cfs. The C.V. for runs dropped below 30%

at 60 cfs and was fairly stable at flows above that level. The C.V. for riffles did not drop

below 30% until flow exceeded about 180 cfs.

Table 5-A. The mean and standard deviation for each of the seven variables that
correspond to the inflection point flows presented in Table 3-A, rimes, n=30.

Variable Mean Std.Dev. 50% 70% 80% 90%
Wetted Perimeter (%) 46.6 12.4 49.5 52.9 54.7 59.8
Wetted Width (ft) 164 52.0 162 192 208 222
Average Depth (ft) 0.50 0.15 0.46 0.51 .057 .067
Change in Stage (ft) 0.84 0.29 0.76 0.91 0.97 1.19
Width/Depth Ratio 453 301 389 521 678 762
Wetted Area (sq ft) 79.5 22.9 71.6 83.6 91.5 106.6
Average Velocity (ftls) 1.47 0.49 1.26 1.60 1.67 2.0

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