WSP04323

• File Number: 8271.300
• Description: Colorado River Basin Salinity Control Program - General Information and Publications-Reports
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 4/2/1982
• Author: Raphael Moses
• Title: Hard Water Makes Hard Law - Water Quality Modifications to the Law of the Colorado River
• Water Supply Pro - Doc Type: Report/Study

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~ the Latin American good-neighbor policy in world peace. The
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Cl::l latter was apparently in reference to the United Nations Orga-
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nizational Conference being held in San Francisco.

Between 1945 and 1961, there were no major problems with

respect to the river, as the salinity of the water delivered to

Mexico at the northerly international boundary was generally

within 100 parts per million of the water at Imperial Dam, the

last major diversion for users in the United States.

In 1947,

the IVellton-Mohawk project in Southwestern Arizona was author-

ized by Congress to deliver water for tht irrigation of 75,000

acres.

It was constructed by the Bureau of Reclamation and

completed in 1952. In 1961, the District comnlenced operation of

a system of drainage wells which discharged saline water into

the Colorado River below the last United States diversion but

above the Mexican diversion. The drainage water included a

substantial portion of highly saline ground water that had been

concentrated through reuse during the previous half century.

Initially, it had the salinity of about 6,000 parts per million.

This resulted in a sharp increase in the salinity of the water

delivered to Mexico from an average around 800 parts per million

in 1960 to plus 1500 in 1962. Mexico raised strenuous objections
to receivinq the drainage waters.

Although the IVellton-Mohawk drainage was the primary cause

of the increase in salinity, a sharp reduction in river flows to

Nexico at around the same time also had an impact. Beginning in

1961, releases into Mexico were sharply reduced in anticipation

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