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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100,000 af/yr) which results in Mexico delivering water into its

Alamo Canal with a salinity of around 950 ppm. These actions are

incorporated in Minute 241, which became effective on July 14, 1972,

and are to remain in effect until December 31, 1972. Minute 218

was terminated when Minute 241 became effective.

It is worth examining for a moment the Mexican position that

they should receive the same quality of water as that at Imperial
Dam. Presently, more than 500,000 af/yr of the water delivered to
Mexico under the 1944 Treaty is derived from return flows below
Imperial Dam. The Wellton-Mohawk Project furnishes approximately
220,000 af/yr, and the balance comes from other United States
projects, including the delivery of drainage water at the southerly
international boundary. All Colorado River water above the 1.5 maf/yr
Treaty obligation to Mexico is committed to use within the United
States. To provide Mexico water of Imperial Dam quality would
either require the conveyance of all return flows below Imperial Dam
to the Gulf of California and the substitution therefor of Colorado

River water (to the detriment of United States users), or would

require a major augmentation of the river or a massive desalting

effort. Desalting of 500,000 af/yr is estimated to cost in the

order of $25 to $50 million a year. Desalting would leave a brine

disposal problem of at least 50,000 af/yr.

Maior Outstanding Issues with Mexico

There are two basic issues with Mexico: (1) Does Mexico have

to receive return flows below Imperial Dam under the 1944 treaty?

I