7906

• UCREFRP Catalog Number: 7906
• Author: Upper Colorado River Basin Instream Flow Team.
• Title: Green River, Determination of Flow Needs Using the Physical Habitat Simulation System ‎(PHABSIM)‎ in the Green River, Utah - Draft.
• USFW Year: 1988.
• USFW - Doc Type: \
• Copyright Material: NO

Table 4. List of the optimum and mean depth and velocity microhabitats
implied from the SI curves for Colorado squawfish and razorback
suckers compared to the mean values observed by Tyus, Jones and
Trinca (1987).
SI curve value Observed value
Depth (ft) Velocity (f/s) Depth (ft) Velocity (f/s)
Colorado sguawfish
Adult 5.18
Deposition 2.04
0.00
2.27
Razorback sucker
Adult
May-June 5.08 0.00-0.34
Jul-Oct 3.44 1.68
5.90 0.82
3.09 1.58
1.97-11.16 ND
<6.56 1.64
move up and down in the water column until a suitable velocity is found
(Figures 4 and 5). Using the modified SI curves the Colorado squawfish
have a minimum optimum depth of 5.18 with velocities between 0.00 and 0.82
f/s, and the depositional life stage has an optimum depth at 2.04 ft and
velocity between 1.58 and 2.27 f/s. The optimum depth for razorback
sucker is at 5.08 ft with velocities between 0.00 and 0.34 f/s in May and
June, and 3.44 ft with velocities between 1.64 and 1.68 f/s from July to
August.
During the development of the curve sets, a rating from A to F (A
being the highest), was assigned to each curve to evaluate the relative
confidence the biologists had in each curve set. The rating was an
indication of the relative accuracy of the SI curves to depict,
microhabitat use. The curve set for Colorado squawfish adults (size 5;
400+ mm) was assigned a confidence rating of "A" for the depth, velocity
and substrate curves (Valdez'et. al 1987). The curve set for deposition
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