WSP03969

• File Number: 8271.300
• Description: Colorado River Basin Salinity Control Program - General Information and Publications-Reports
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 8/11/1972
• Author: Myron Holburt
• Title: The Mexican Water Treaty and Its Relationship to Colorado River Water Supplies
• Water Supply Pro - Doc Type: Report/Study

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Extensive negotiations were conducted between 1962 and 1965
and in November 1965, with the concurrence of the Committee of Four-
teen, a f:i,ve-year agreement was incorporated in Minute 218 of the in-
ternational Boundary and Water Commission. Under Minute 218, the
United States agreed to take several actions to alleviate the
problem. First, the United States constructed an extension of the
Well ton-Mohawk Drain so that water can either be bypassed around
Morelos Dam or mixed with other Colorado River waters above Morelos

Dam, at the option of Mexico. Second, the United States constructed
additional drainage facilities in the Wellton-Mohawk project which
allow selective pumping of the most saline waters at times when

Mexico is bypassing Wellton-Mohawk drainage water, and allow the

pumping of higher quality groundwater at times when Mexico is using

Wellton-Mohawk water. Third, the United States agreed to replace

a portion of the bypassed Wellton-Mohawk water which resulted in the

release of approximately 40,000 acre-feet of mainstream water per

year from Imperial Dam in excess of the 1.5 million acre-feet per

year required by the Treaty.

Minute 218 was extended for one year in November 1970, and

again extended in November 1971. Under the measures taken by the

United States, at a cost of about $12 million, the quality of the

water delivered to Mexico was improved from about 1500 ppm in 1962

to 1240 ppm in 1971. Between November 1965 and November 1971,

operation of the minute has resulted in delivery to Mexico of

232,000 acre-feet in addition to the amount guaranteed by the Treaty.

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