4001

• UCREFRP Catalog Number: 4001
• Author: U.S. Bureau of Reclamation.
• Title: Colorado River System Consumptive Uses and Losses Report 1976-1980.
• USFW Year: 1981.
• USFW - Doc Type: Washington, D.C.
• Copyright Material: NO

Introduction
The Colorado River system is com-
posed of portions of seven States -
Arizona, California, Colorado, Nevada,
New Mexico, Utah, and Wyoming. It
has a drainage area of about 242,000
square miles and represents about
one-fifteenth of the area of the United
States. This report incorporates
annual estimates of consumptive uses
and losses of water from the system
from 1976 to 1980, Wherever available,
water use reports prepared in accord-
ance with legal requirements concerning
the operation of the Colorado River
were utilized. Base data needed to
estimate onsite consumptive uses were
taken largely from existing reports and
studies and from ongoing programs.
Where current data were not available,
estimated values were developed by
various techniques and reasoned judg-
ment. In general, methodology followed
the techniques normally used within the
system for estimating water use.
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. 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).
Authority
The authority for this report is
contained in Public Law 90-537, the
Colorado River Basin Project Act of
1968. Title VI, Section 601(b)(1) of
the act reads as follows:
(b) The Secretary is directed to-
(1) Make reports as to the annual
consumptive uses and losses of
water from the Colorado River
system after each successive
five-year period, beginning with
the five-year period starting
October 1, 1970. Such reports
shall include a detailed break-
down of the beneficial consump-
tive use of water on a State-by-
State basis. Specific figures
on quantities consumptively used
from the major tributary streams
flowing into the Colorado River
shall also be included on a
State-by-State basis. Such
reports shall be prepared in
consultation with the States of
the lower basin individually and
with the Upper Colorado River
Commission, and shall be trans-
mitted to the President, the
Congress, and to the Governors
of each State signatory to the
Colorado River Compact.
Plan of Study
A proposed plan of study was pre-
sented for comment to representatives
of the Upper and Lower Basin States
and the Upper Colorado River Commis-
sion. Comments received principally
concerned water accounting procedures.
This issue is longstanding and is
related to the interpretation and
implementation of the legal documen-
tary controlling the operation of the
river. In the Upper Basin, the prin-
cipal comment concerned the use of
accurate data bases, particularly
irrigated acreage. The Lower Basin
comments concerned the lack of credit
for unmeasured return flows originat-
ing from mainstream diversions and the
failure to quantitatively recognize
that ground water overdraft in the
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