PUB00155

• Year: 2007
• Title: The Colorado River The Story of a Quest for Certainty on a Diminishing River
• CWCB Section: Administration
• Author: Eric Kuhn
• Description: The Colorado River The Story of a Quest for Certainty on a Diminishing River
• Publications - Doc Type: Other

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The White River joins the Green approximately forty miles south of its confluence with the
Duschene. The White River drains an area of western Colorado that could, at some future time, be
the epicenter of an oil shale industry.

The Green River drainage basin is rich in energy resources including natural gas, oil, coal,
and oil shale reserves. The Green River is an important environmental resource. It is home to four
endangered fish species under the ESA. The stretch of river from the Colorado above Lake Powell
then up the Green and again up the Yampa is the longest continuous unblocked stretch of occupied
habitat within the Colorado River system for these fishes.34

The Upper Colorado River Mainstem: The Colorado River mainstem basin covers the
Colorado River and its tributaries above its confluence with the Green River. Prior to 1921, this
stretch of the Colorado River was referred to as the Grand River.35

The upper mainstem basin drains an area approximately 25,600 square miles, less than half
the drainage area of the Gila River system and approximately 55% of the drainage area of the Green,
yet it is the largest contributor of flow to the river system. The estimated natural flow of the Colorado
mainstem is in the range of6.6 mafper year.36

The Colorado River has its headwaters in Grand County, Colorado, originally at the natural
outlet of Grand Lake.37 As the river flows to the west, it is joined by its major tributaries; the Blue
River, the Eagle River, the Roaring Fork River which enters the river at Glenwood Springs,
Colorado, the Gunnison River at Grand Junction, Colorado and the Dolores River near Cisco, Utah.
Ofthese tributaries, the Gunnison River is the largest, draining an area of 8,000 square miles and
providing a natural flow of approximately 2.3 maf per year. The Colorado mainstem and its
tributaries are the drainage for the spine of the Colorado Rocky Mountains and the northern slopes
ofthe San Juan Mountains. Its watershed also includes parts of the White River, Uncompahgre and
Grand Mesa Plateaus.

The headwaters of the Colorado River mainstem are home to a number of trans mountain
diversions which divert Colorado River water across the Continental Divide to the Colorado Front
Range. These transmountain diversions serve municipal and agricultural needs from Pueblo to Fort
Collins including the Metropolitan Denver and Colorado Springs areas.

34The Upper Colorado River Basin Endangered Fishes Recovery Program has published numerous reports and studies on the Green
River system. The Final EIS for the reoperation of Flaming Gorge (November 2005) describes the importance of the Green River
in Chapter 1.

35In 1921, Congress changed the name of the Grand River to the Colorado River. The bill was, of course, sponsored by the State
of Colorado delegation.

36The author's estimate using the 7.0 mafper year number reported by the Engineering Committee to the Upper Colorado River Basin
Compact Commission. It's corrected to a lower Lee Ferry estimate. See footnote 29.

37The construction of the Colorado-Big Thompson Project in fact reversed the flow of the natural outlet of Grand Lake. It is now an
inlet for project water as it moves from Granby Reservoir through Shadow Mountain Reservoir to the west portal of the Adams Tunnel
which is located on the eastern shore of Grand Lake.

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