8013

• UCREFRP Catalog Number: 8013
• Author: Pontius, D. and I. SWCA.
• Title: Colorado River Basin Study.
• USFW Year: 1997.
• USFW - Doc Type: Tucson, Arizona.
• Copyright Material: NO

Colorado River Basin Study

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Writing about the Colorado River is an awesome challenge given the body of
scholarly work and commentary that has been done over the years on the
Colorado River. I have mined some but not of all this material in the limited
time allotted for this report and have included a representative but by no
means complete bibliography of the voluminous literature that exists on the
subject.

Background Information

The Colorado is one of the great rivers of the American West. It has a
dramatic history going back millions of years; within its watershed are
located some of the most majestic geologic features in North America,
including the Grand Canyon. Today, it is considered the lifeline of the
Southwest, providing water for nearly 25 million people, three million acres
of irrigated land, and 11.5 billion kilowatt-hours of hydroelectric power. Its
water yield is only eight percent of the annual flow of the Columbia and
three percent of the Mississippi, yet it is arguably the most regulated river in
the country, and has spawned the most litigation and controversy. The river
has been the source of disputes between states, between the United States
and Mexico, between cities and farms, between power users and
conservationists, and between Indian tribes and non-Indian water users. To
provide context for the current issues in the Colorado River basin, the
geography, hydrology, water development, and water uses in the basin are
described below.

Geography

The Colorado River basin, depicted in Figure 1, covers almost a quarter of a
million square miles and includes portions of seven states, part of Mexico,
and 34 Indian reservations. Reservation lands in the basin are depicted in
Figure 2. The federal government owns 56 percent of the land within the
basin, Indian reservations occupy 16.5 percent, states 8.5 percent, and
19 percent is privately owned land (Weatherford and Brown, 1986).
Approximately two percent of the basin is in Mexico. The Salton Sea was
filled when the Colorado River broke its channel in 1905 and flowed into the
Imperial Valley for three years before it was contained. It is now replenished
primarily by return flows from the Imperial Irrigation District and other
discharges of waste water into the New River. Additional areas outside the
natural drainage area, including the Imperial and Coachella valleys and

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