9520

• UCREFRP Catalog Number: 9520
• Author: Haines, G. B., D. Irving and T. Modde.
• Title: White River Base Flow Study for Endangered Fishes, Colorado and Utah, 1995-1996.
• USFW Year: 2004.
• USFW - Doc Type: 5D,
• Copyright Material: NO

to those used in earlier studies (Archer et al. 1980; Miller et al. 1982) prior to completion of

Taylor Draw Dam (1985), and the fourth stratum ended at the dam.

All strata were further subdivided into smaller sampling units called habitat clusters

(Figures 2 and 3). The length of each habitat cluster contained at least two representative pool-

run-riflle habitat sequences. Leopold et al. (1964) and Bovee (1982) found that a simple pool.

run-riffle habitat sequence repeated itself in distance equivalent to five times the mean channel

width. The habitat cluster length in the White River was equal to 10 times the mean channel width

to capture two habitat sequences. The mean river channel width was calculated from

measurements taken from aerial photographs.

Each habitat cluster was numbered and located by RM on a topographic map. A random

numbers table was used to select 25 habitat clusters in each stratum to sample mesohabitat data

during each flow and year (25 clusters * 4 strata * 3 flows * 2 years = 600 clusters). One habitat

cluster was strategically placed at the Watson, Utah, u.s. Geological Survey (USGS) gage, just

downstream from Ignacio Bridge on Highway 45, to aid in making comparison with the historical

USGS gage data.

Two habitat cross sections were randomly placed perpendicular to the flow across the

river in each habitat cluster to collect mesohabitat (pool, riffle, eddy, run) and microhabitat

(depth, velocity) data. Figures 2 and 3 describe habitat clusters in each stratum and how cross

sections were located.

Data Collection

Field crews conducted a reconnaissance float trip down the White River in the early

4