7806

• UCREFRP Catalog Number: 7806
• Author: U.S. Department of the Interior.
• Title: Quality of Water, Colorado River Basin.
• USFW Year: 1997.
• USFW - Doc Type: Progress Report No. 18,
• Copyright Material: NO

Chapter 1

section 15 of the Colorado River Storage Project Act (70 Stat. 111; 43 U.S.c. 602n),
section 15 of the Navajo Indian Irrigation Project (NIIP), and the initial stage of the
San Juan-Chama Project Act (76 Stat. 102), and section 6 of the Fryingpan-Arkansas
Project Act (76 Stat. 393)."

LEGAL ASPECTS

Water Quantity

Apportionment of the use of Colorado River water has been accomplished by the Colorado River
Compact of 1922, the Boulder Canyon Project Act of 1928, the Water Treaty of 1944, the Upper
Colorado River Basin Compact of 1948, and the U.S. Supreme Court (State of Arizona v.
California et al., 1964).

The Colorado River Compact divided the Colorado River between the Upper and Lower Basins at-
Lee Ferry Gust below the confluence of the Paria River), apportioning to each use of 7.5 million
acre-feet (mat) annually. In addition to this apportionment, the Lower Basin was given the right
to increase its beneficial consumptive use by 1 million acre-feet per year. The compact also
contains provisions governing exportation and obligations to Indian Tribes. The Water Treaty of
1944 obligates the United States to deliver to Mexico 1.5 million acre-feet of Colorado River
water annually.

The Upper Colorado River Basin Compact of 1948 divided and apportioned the use of water
apportioned to the Upper Basin by the Colorado River Compact, allocating to Arizona use of
50,000 acre-feet annually, with the remaining use of water allocated to Upper Basin States as
follows: Colorado, 51.75 percent; New Mexico, 11.25 percent; Utah, 23 percent; and Wyoming,
14 percent. The compact permitted the authorization of Federal projects above Lee Ferry.

States of the Lower Basin, however, did not agree to a compact for the apportionment of waters in
the Lower Colorado River Basin; accordingly, a-Supreme Court decree (Arizona v. California et
al.) in 1964 allocated use of the mainstem of the Colorado River below Lee Ferry among
California, Nevada, and Arizona, and the Gila River between Arizona and New Mexico. From the
main stem of the Lower Colorado River, Nevada was apportioned 300,000 acre-feet annually plus
4 percent of the surplus water available; Arizona was apportioned 2,800,000 acre-feet annually
plus 46 percent of the surplus water available; and California was apportioned 4,400,000 acre-feet
annually plus 50 percent of the surplus water available. The decree also permitted the Secretary of
the Interior (Secretary) to make water unused in one State available in another State and allowed
Federal water projects and the development of Indian tribal lands to proceed.

Nothing in this report is intended to interpret the provisions of the Colorado River Compact
(45 Stat. 1057), the Upper Colorado River Basin Compact (63 Stat. 31), the Water Treaty of 1944
with the United Mexican States (Treaty Series 994; 59 Stat. 1219), the decree entered by the
Supreme Court of the United States in Arizona v. California et al. (376 U.S.c. 340), the Boulder
Canyon Project Act (45 Stat. 1057), the Boulder Canyon Project Adjustment Act (54 Stat. 774;
43 U.S.C. 618a), the Colorado River Storage Project Act (70 Stat. 105; 43 U.S.C. 620), or the
Colorado River Basin Project Act (82 Stat. 885; 43 U.S.C. 1501).

2