9614

• UCREFRP Catalog Number: 9614
• Author: Bowen, Z. H. and e. al.
• Title: Habitat Measurement and Modeling in the Green and Yampa Rivers.
• USFW Year: 2001.
• USFW - Doc Type: \
• Copyright Material: NO

6
INTRODUCTION
Review of physical studies
The Green River originates in the Wind River Mountains of Wyoming and flows
1,230 km southeasterly through Colorado and Utah until its confluence with the Colorado
River near Moab, Utah. The Green River drains approximately 115,800 km2 and is a
principal tributary to the Colorado River. Elevations in the basin range from over 4,200
m in the headwaters to about 1,200 m at the Colorado River confluence (Muths et al.
1999). Climate is variable across the basin but most of the total annual stream flow is
provided by snowmelt runoff during late spring and early summer resulting in a mean
annual discharge of about 124 m% at the Jensen, UT steam gage (1947-1999). Principal
tributaries of the Green River include the Blacks Fork, Yampa, Duchense, White, Price,
and San Rafael Rivers (Andrews 1986). The character and geomorphology of the Green
River varies from steep and narrow canyons to low-gradient meandering reaches.
Canyon reaches occur where highly resistant lithologies are exposed at the river level
while meandering reaches are found in areas of moderate to low-resistance lithology
(Grams and Schmidt 1999). Substrates are predominantly gravel or cobble in steeper
reaches and sand in lower gradient reaches (Schmidt 1996). Meandering reaches contain
an order of magnitude more alluvium per area than canyon reaches and store sediment in
mid-channel bars and broad floodplains while in canyon reaches most sediment is stored
in debris fan-eddy complexes (Grams and Schmidt 1999).
Flows and sediment transport in the Green River have been altered by the
construction of dams and reservoirs. The two largest reservoirs in the Green River
Drainage are Strawberry Reservoir on the Duchense River and Flaming Gorge Reservoir