Colorado River Subunit and Law of the River Me

• Title: Colorado River Subunit and Law of the River
• Date: 6/19/2007
• Author: James Eklund
• Interbasin CC - Doc Type: Presentations

S L R
UMMARY OF THE AW OF THE IVER

The Law of the River is a complex tapestry of interstate compacts, federal law, and
agreements. The basic threads of the Law of the River are:

Colorado River Compact (1922)
— apportions water betwee n the Upper and Lower
Basins (7.5 million acre - feet to each) with the requirement that the Upper Division not
deplete the flow of water below an aggregate of 75 million acre - feet over any period of
ten consecutive years .
Boulder Canyon Project Act (1928)
— a llocat es Lower Basin water among Arizona,
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California, and Nevada ; authorized construction of Hoover Dam and the All - American
Canal.
California Limitation Act (1929)
— obligates California to limit its use to 4.4 million
acre - feet.
California Seven - Party Agr eement (1931)
— divided 5.3 million acre - feet of water
among seven large California water users.
United States - Republic of Mexico Water Treaty (1944)
— allocates 1.5 million acre -
feet of water to Mexico plus an additional .2 million acre - feet if there is a sur plus;
requires Mexico to share shortages that are due to "extraordinary drought" in the United
States.
Upper Colorado River Basin Compact (1948)
— apportions water between Arizona (.05
million acre - feet), Colorado (51.75%), Utah (23%), Wyoming (14%), and
New Mexico (1 1.25%) and creates the Upper Colorado River Commission.
Colorado River Storage Project Act (1956)
— assists the Upper Basin States in
developing storage projects to ensure Compact deliveries (e.g. Glen Canyon, Flaming
Gorge, Aspinall, Navajo).
decision and decree (1963 and 1964)
Ariz ona v. California — sustains federal claims on
behalf of Lower Basin American Indian tribes and interprets the BCPA as allocating
water among Ar izona (2.8 million acre - feet) , California (4.4 million acre - feet) , and
Nevada (.3 million acre - feet) .
Colorado River Basin Project Act (1968)
— authorized construction of the Central
Arizona Project and states that, in times of shortage, California use takes priority over
any Central Arizona Project use; directs the Secretary of the Interior to propose Long
R ange Operating Criteria for the reservoirs.
Operating Criteria for Colorado System Reservoirs (1970)
— targets a delivery of 8.23
million acre - feet from Lake Powell to Lake Mead (note that this is not required by the
Compacts); co ntemplates an annual review and plan taking into account water in storage
and anticipated runoff.

A s interpreted and decreed by the Supreme Court in Arizo na v. California .
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373 U.S. 546 (1963) (decision), 376 U.S. 340 (1964) (decree), ___ U.S. ___, 126 S.Ct. 1543
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(2006) (consolidated decree) .

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