WSP09929

• File Number: 8200.700
• Description: Colorado River Basin - General Publications
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 5/4/1979
• Author: Comptroller General
• Title: Colorado River Basin Water Problems - How to Reduce Their Impact - Report to the Congress of the United States
• Water Supply Pro - Doc Type: Report/Study

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In 1948 the four Upper Basin States, plus Arizona,
entered into the Upper Colorado River Basin Compact, which
apportioned rights to the Upper Basin water among the States.
The Boulder Canyon Project Act of 192B (43 U.S.C. 617) appor-
tioned 7.5 maf of the Lower Basin's allocation among the three
Lower Basin States; however, the States did not agree with the
amounts. After much controversy, the Suprene Court confirmed
the allocations in its Arizona v. California decree of 1964
(376 U.S. 340).

In summary, as a result of the compacts, the Boulder
Canyon Project Act, the Mexican Water Treaty, and the Supreme
Court decree, the Colorado River waters have been apportioned
as follows:

--Each sub-basin is entitled to consumptively use 7.5
maf annually.

--In the Lower Basin the 7.5 maf was apportioned as
4.4 maf to California, 2.8 maf to Arizona, and 300,000
acre-feet to Nevada.

--In addition, the Lower Basin has been allocated 1 naf
which has not been divided among the Lower Basin States.

--The Upper Basin's entitlement apportioned 50,000 acre-
feet to Arizona; the remainder of the 7.5 maf appor-
tioned 51.75 percent to Colorado, 11.25 percent to
New Mexico, 23 percent to Utah, and 14 percent to
Wyoming.

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--Under the treaty with Mexico, the united States is
obligated to deliver 1.5 mar annually to Mexico.

--Five Indian reservations along the Colorado River
have a grant of rights to divert about 1 maf, to
be deducted from California and Arizona's entitle-
ment.

COMPETING NEEDS FOR WATER

Demands for water in both sub-basins have been mainly
for agricultural, municipal, and industrial use to serve the
mushrooming population, sustain the traditionally high
industrial growth rates, and support some of the Nation's
most fertile agricultural lands. Recently, demands have
increased for water to use in developing energy resources.
The Nation's largest reserves of coal, oil shale, tar sands,
and uranium are located in the Upper Basin. Development of
these resources will depend onnany factors, including
availability of water. Historical water use patterns may

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