8030

• UCREFRP Catalog Number: 8030
• Author: Tyus, H. M., C. W. McAda and B. D. Burdick.
• Title: Green River Field Investigations
• USFW Year: 1981.
• USFW - Doc Type: 1979-1981 Draft of the Final Report.
• Copyright Material: NO

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Methods
Standardized Sampling Program
The standardized program was designed for sampling about 300 miles
(480 km) of the Green River in 1979-1981: from Turks Head at RM 22 (km
35) to Split Mountain, RM 320 (km 515). Since it was impossible to
adequately sample this entire riverine area with allocated manpower it
was necessary to develop a sampling program.
The river system consists of several 30 to 70 mile sections of
relatively homogeneous fishery habitat, including high-gradient canyons,
low-gradient braided sections and transition zones between these two
main types. The development of the sampling design incorporated treatment
of these homogeneous sections as discrete strata (Figure 2) in order to
provide a good distribution of samples and reduce within-strata sampling
variablity. Criteria incorporated into the delineation of strata included
both geophysical (river channel configuration, substrate types, gradient
and depth) and biological parameters (productive bottomlands, sterile
sand flats, productive backwaters, swift canyons and point sources of
allochthonous organic materials).
The six homogeneous strata were as follows:
Length
Stratum (mi) River Milesa Landmark Deseriptiori
A 71 22-93 Turks Head to Labyrinth Canyon
B 37 94-131 Labyrinth Canyon to Gunnison Butte
C 24 132-156 Gunnison Butte to Three Ford's Rapid
D 54 157-211 Three Ford's Rapid to Duche's Hole
E 37 212-249 Duche's Hole to Duchesne River
F 70 250-320 Duchesne River to Split Mountain
Sampling Design and Procedure
Sampling procedures were presented in Archer et al. (1979). During
the first year, samples were drawn to establish the sampling sequence.
One stratum (B) was selected as the starting point with the sampling
series progressing sequentially downstream to the last stratum, shifting
back to the uppermost stratum to complete the series. Within each
stratum, a sample site was selected according to a completely random
sampling design. Each stratum was divided into river-mile stations. In
order to avoid sampling bias in the selection of stations, a table of
random digits was consulted and the first number encountered in the
table that appeared in the section was chosen for the sample station.
To permit replication and to insure that representative stations were
chosen, each station consisted of two 0.5 mile reaches; one extending
a River mile from confluence of the Green and Colorado Rivers