PUB00089

• Year: 1980
• Title: Upper Colorado Resource Study: Colorado and Utah - Concluding Report May 1980
• CWCB Section: Water Conservation & Drought Planning
• Author: R. Keith Higginson, Commissioner
• Description: Study to determine expected increases of water needs for energy-related developments along White and Yampa Rivers
• Publications - Doc Type: Tech Report

CHAPTER IV

DESCRIPTION OF AREA

.

Most of the northern limits of the area lie in geomorphic features
of the Wyoming Basin. In northern Routt and northeastern Moffat County,
one of these features is the Elkhead Mountains, extending westward from
the Sierra Madre Range. These mountains are slightly lower and of
gentler relief than those to the east. West of the Elkhead Mountains
the area boundary runs through the low rolling hills of the Sand Wash
Basin. In western Moffat County the northern boundary of the area is
Douglas Mountain, an extension of the Uinta Mountains.

The southern boundary of the area is formed by the divide which
separates the Yampa and White River drainages from the Colorado River
mainstem drainage. This divide includes the southern portion of the
White River Plateau to the east and the Roan Plateau to the west. The
White River Plateau is a westerly extension of the Southern Rocky Moun-
tains. It is an area of subdued relief with elevations ranging mostly
from 8,500 to 11,000 feet. The Roan Plateau lies to the west of the
White River Plateau and is a feature of the Piceance Creek Basin of the
Colorado Plateau. It is of still gentler relief and elevations rarely
exceed 9,000 feet. The White River and Roan Plateaus are separated by
the Grand Hogback, a prominent north-south ridge formed by steeply
dipping sandstone beds.

The western boundary of the area is the Green River.

The divide between the Yampa and White River drainages is of dis-
tinct but variable topography. In the eastern one-third of the area,
the divide is composed of the eastern and northern portions of the
White River Plateau. The Danforth Hills, a range of low mountains
with elevations of 7,000-8,000 feet, extend westerly from the north-
west part of the White River Plateau between the two river basins.
West of the Danforth Hills, the divide lies along a reach of low-rolling
topography known as the Gray Hills. Between 30 and 40 miles east of the
Colorado-Utah State line, the Gray Hills grade into the higher Yampa
Plateau, an extension of the Uinta Mountains south of and parallel to
Douglas Mountain.

.

Elevations in the area range from 4,640 feet at the mouth of the
White River to more than 12,000 feet at numerous points at the eastern
end of the area (BR 1957).

River basins

Both the Yampa and White Rivers are tributaries of the Green River,
which is a tributary of the Colorado River. The combined drainage area
of the White and Yampa Rivers comprises about 12 percent of the Upper
Colorado River Basin and produces about 15 percent of the total runoff
of the Colorado River at Lees Ferry, the dividing point between the
Upper and Lower Colorado River Basins. Streamflow records and estimates

.

24