7962

• UCREFRP Catalog Number: 7962
• Author: Wolz, E. R. and D. K. Shiozawa.
• Title: Benthic Invertebrates from the Green River, UT, Benthic Macroinvertebrate Communities of the Green River, at the Ouray National Wildlife Refuge - master's theses.
• USFW Year: 1993.
• USFW - Doc Type: Brigham Young University,
• Copyright Material: NO

STUDY SITES
The Green river originates in Wyoming and flows south through eastern Utah to
its confluence with the Colorado (Fig. 1). It adds more volume to the Colorado River
system than any other river. In eastern Utah, at river km 404, the Green River enters
the Ouray National Wildlife Refuge area. We collected the monthly samples for this
study in the Ouray National Wildlife Refuge during June to August 1991 in the following
four different habitats associated with the Green River (see also Fig. 2).
River channel: The river channel was sampled at a site approximately 3 km north of
the U.S.F.W.S. hatchery on the Ouray National Wildlife Refuge. Sampling was adjacent
to a sand bar that decreased turbulence preventing shifting sands. The substrate consisted
mostly of sand with very little silt and detritus. Water levels were too high during June
(peak flow) to allow sampling.
Ephemeral side channel: During high flows, the Green River will occupy various
smaller channels which are dry during non-peak flow. We have termed these smaller
channels "ephemeral side channels". The ephemeral side channel we selected for study
was approximately ? km south of the U.S.F.W.S hatchery. Most of the year, water
levels are below the level of the ephemeral side channel. However, during peak flow,
water filtered through a wooded area and gathered into a channel 10 m wide and 500 m
long. As the river level dropped, flow slowed and eventually stopped. The side channel
dried up between the July and August samples. The substrate consisted mostly of firm
silt and detritus with very little sand. Sediment deposition contributed little to the site
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