WSP05261

• File Number: 8271.200
• Description: Colorado River Basin Salinity Control Program - Development and History
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 4/12/1974
• Title: The Colorado River Basin Salinity Control Act - Western States Water Council - April 12 1974 -
• Water Supply Pro - Doc Type: Report/Study

Western States Water Council
Meeting

Boise, Idaho
April 12, 1974

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was paying all of the costs of controlling the flows of the river,
Mexido should be entitled only to actual usage prior to the completion
of Hoover Gam, a maximum of 750,000 acre-feet per year.

During World War II, in the interest of international comity, the
U. S. agreed to the compromise contained in the Treaty, a guaranteed
delivery, except under conditions of extreme drought, of 1,500,000
acre-feet annually to Mexido with minimum and maximum rates of
delivery during the year designed to permit the United States to
receive credit for all irrigation return flows expected to enter the
lower river. The Treaty is silent on the matter of water quality,
but states that while deliveries must be waters of the Colorado River
they may be "from any and all sources"., . "whatever their origin."

The record of the United States Senate in consideration of
ratification of the Treaty and of the correspondence 01' those who
participated in its negotiation make it clear that the two countries
contemplated that a substantial portion of the water to be delivered
to Mexido would be made up of drainage waters or return flows from
uses in the United States. It seems equally clear that the Mexican
negotiators expected that. the waters allocated under the Treaty would
be usable for agricultural purposes,

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Even though use in the United States continued to increase and
the salinity of the waters delivered increased somewhat, no serious
problems arose concerning deliveries of Colorado River waters
to Mexico under provisions of the Treaty' until late in 1961. Two
events occurred at that time, .however, to precipi:ate a formal
protest by Mexico: the drainage system for the Wellton-Mohawk
Irrigation and Drainage District was completed and went into
operation and, at about the same time, storage of river flow in
Lake Mead was increased in anticipation of the commencement
of the filling of Lake Powell and flows available to dilute agri-
cultural returns il'cl\ sharply. For the decade from 1951-60 the
flow of the Colorado River at the northerly international boundary
with Mexico averaged 4,240,000 acre-feet per year, while for the
1961-70 decade, the flow averaged only 1,521,000 acre-feet per year,
reduction of 2,719,000 acre-feet per year.

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