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

INTRODUCTION
General
The Vernal Field Station was staffed in May 1979. Field sampling
of approximately 300 miles (480 km) of the Green River began in July.
Field work was divided into a Standardized Sampling Program and a Spe-
cial Investigations Program. The standardized program characterized
fishery habitat and species distribution; the special investigations
program provided in-depth studies of life history requirements of rare
and endangered fishes. It is important to note that collections using
different methods between seasons and locations are reported. These
different collections are cited when data are reported.
Two other studies, the White River and Yampa River investigations,
conducted by the Vernal station are not included in this report. These
two studies included work in the upper Green River and provided other
information directly related to this study. For a holistic understanding
of the Green River ecosystem, these other studies should be considered
with this study. The White River study (funded largely by the Bureau of
Land Management) and the Yampa River study (funded by Congress, the
National Park Service and the Fish and Wildlife Service) will be available
February 1982.
Setting
The Colorado River Basin is separated into upper and lower basins
near Lee's Ferry, Arizona. The upper basin is further subdivided into
its three major river systems, or hydrologic sub-basins; Green, upper
main stem and San Juan-Colorado (Figure 1).
2 The Green River sub-basin comprises bout 45,000 sq. miles (116,000
km ) of the 109,500 sq. miles (284,000 km ) occupied by the Upper Colorado
Basin. The Green River is the largest tributary to the Colorado River
and extends about 500 linear miles to its source, the Wind River Range
in western Wyoming.
The study area extends from Split Mountain, the lower boundary of
Dinosaur National Monument, to the confluence of the Green and Colorado
Rivers in Canyonlands National Park. The Yampa River, the major tributary
to the Green, enters the Green in the Monument. The Green River above
the mouth of the Yampa River is strongly influenced by releases from
Flaming Gorge Dam, constructed in 1963.
The Green River flows through different geologic formations and
has several tributaries as it proceeds to its mouth. Leaving Dinosaur
National Monument, the Green River flows into the Uinta basin, an open
valley. The Duchesne River enters near Ouray, Utah, draining the southern
slope of the Uinta Mountains. The White River enters below the mouth of
the Duchesne, having its headwaters on the western slope of the Rocky
Mountains. Below these principle tributaries, the Green proceeds 120
miles (193 km) through Desolation and Gray Canyons. The Price River
enters the Green in lower Gray Canyon. The Green River then enters the