WSP03306

• File Number: 8281.300
• Description: Colorado River Studies and Investigations - Colorado River Consumptive Uses and Losses Report
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1984
• Title: Colorado River System Consumptive Uses and Losses Report 1976 - 1980
• Water Supply Pro - Doc Type: Report/Study

Terminology
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WThe Colorado River is not only one of
~th'e most highly controlled nvers in
~he world, but is also one of the most
~institutionallyencompassed. A multi-
tude of legal do~uments, known collect-
ively as the "Law of t'he River,"
affect and always dictate its manage-
ment and operation. Majo.r docu-
ments include:

Colorado River Compact - 1922
Boulder Canyon Project Act - 1928
California Limitation Act 1929
California Seven Party Agreement -
1931
Mexican .Water Treaty - 1944
Upper Colorado River Basin Compact -
1948
Colorado River Storage Project Act -
1956
United States ~upreme Court Decree in
Arizona v. California - 1964
Colorado River Basin Project Act -
1968
Minute 242 of'the International Bound-
ary and Water Commission, United
States and Mexico - 1973
Colorado River Basin Salinity Control
Act - 1974

The Colorado River system is defined
in the Colorado' River Compact of 1922
as" "" that portion of the Colorado
River .Iud its tributaries within the
United States,", whereas the Colorado
River Basin is defined as.". . . all of
the drainage area of the Colorado River
system and all other territory within
the United States of America to which
waters of the Colorado River system
shall be beneficially applied." The
compact, divided the Colorado River
Basin into two sub-basins - the "Upper
Basin" and the "Lower Basin," with Lee
Ferry as the division point on the
river. Lee Ferry, located in Arizona,
is a point in the mainstream 1 mile
below the mouth of the Paria River.
For the purpose of this report, the

Great Divide Basin, a closed basin in
Wyoming, and the White River in Nevada
have not been considered as part of the
Colorado River system. Diversions from
the system to areas outside its drain-
age area are conside.red herein as
exports and have not been classified as
to types of use.
Beneficial consumptive use is
normally construed to mean the consump-
tion of water brought about by human
endeavors and in this - report includes
use of water for municipal, industrial,
agricultural, power generation, export,
recreation, fish and wildlife, and
other purposes, along with the assoc-
iated losses incidental to these
uses.
The storage of water and water in
transit may also act as losses on the
system although normally such water is
recoverable in tinie. Qualitatively,
What constitutes beneficial consumptive
use is fairly well understood; however,
an inability to exactly quantify these
uses has led to various differences of
opinion. The practical necessity of
administering the various water rights,
apportionments, etc., of the Colorado
River has led to definitions of con-
sumptive use or depletions generally in
terms of "how it shall be measured."
The Upper Colorado River Basin Compact
provides that the Upper Colorado River
Commission is to determine the appor-
tionment made to each State by ". . .
the inflow-outflow method in terms of
manmade depletions of the virgin flow
at Lee Ferry . . . ." There is further
provision that the measurement method
can be changed by unanimous action of
the Commission. In contrast, article
leA} of the decree of the Supreme Court
of the United States in Arizona v.
California defines, for, the purpose of
the decree, "Consumptive use means
diversions from the stream less such
return flows thereto as are available
for consumptive use in the United

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