WSP06755

• File Number: 8270.100
• Description: Colorado River Basin Water Quality/Salinity -- Misc Water Quality
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1995
• Author: USDOI
• Title: Quality of Water - Colorado River Basin - Progress Report No. 17 - January 1995
• Water Supply Pro - Doc Type: Report/Study

the biennial report on the quality of water of the Colorado River Basin
prepared by the Secretary pursuant to section 15 of the Colorado River Storage
Project Act (70 Stat, 111; 43 U.S.C. 602n). section 15 of the Navajo Indian
N Irrigation Project (NIIP), and the initial stage of the San Juan-Chama Project
CJl Act (76 Stat. 102), and section 6 of the Fryingpan-Arkansas Project Act
~ (76 Stat. 393)."

LEGAL ASPECTS

Water Quantity

Apportionment 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 (just below the confluence of the Paria River), apportioning to
each 7.5 million acre-feet (maf) 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 (aflyr). 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 water
apportioned to the Upper Basin by the Colorado River Compact, allocating to Arizona
5P,000 acre-feet annually, with the remaining 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 mainstem of the Lower Colorado River,
Nevada was apportioned 300,000 acre-feet annually; Arizona was apportioned
2,800,000 acre-feet annually; and California was apportioned 4,400,000 acre-feet
annually. The decree also permitted 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 ai, (376 U,S.C. 340), the Boulder Canyon Project Act (45 Stat, 1057), the

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