WSP10281

• File Number: 8278.300
• Description: Title I - Mexican Treaty
• Basin: Colorado Mainstem
• Date: 9/1/1991
• Author: Anne DeMarsay CRBSCF
• Title: The Brownell Task Force and the Mexican Salinity Problem - A Narrative Chronology of Events
• Water Supply Pro - Doc Type: Publication

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The Brownell Task Force and the Mexican Salinity Problem:
A Narrative Chronology of Events

Introduction

Seventeen years ago this summer, in June 1974, President Nixon signed into law P.L. 93-320,
the Colorado River Basin Salinity Control Act. Title I of the Act authorized the Federal
Governmnet to take measures to eliminate the effects of brackish return flows (or drainage) from
the WeIIton-Mohawk irrigation project on water delivered to Mexico under a 1944 treaty
allocating the waters of the Rio Grande, Tijuana, and Colorado Rivers between the U.S. and its
southern neighbor. At the heart of the Title I program was a 100 million gallon-per-day (mgd)
desalting plant to be built at a site near Yuma, Arizona. The desalting plant was to be the
solution to a water quality dispute that had periodically troubled U.S.-Mexican relations since
1961.

The Yuma Desalting Plant was to remove 90 percent of the dissolved salts from the return
flows, by a process called reverse osmosis. This desalted water was then to be blended with the
remaining drainage to yield water of the quality guaranteed Mexico under a 1973 Minute to the
original treaty, Minute No. 242. The estimated capital cost of the plant, along with other
measures called for in Title I, was estimated at slightly under $100 million at the time of
authorization.

Completion of the plant is now thirteen years behind the original schedule. Its capital cost has
risen to more than $400 million, and projected yearly operation and maintenance costs range
from $10 million to $33 million. The blended waters to be delivered to Mexico may cost as
much as $500 per acre-foot to produce. I

Why did the Federal government choose such a costly-and risky-means to implement an
international agreement? To answer that question, we must look at the history of that
decision-the people involved, their perspectives and limitations, the courses of action they
believed were available, and the constraints under which they worked. But first, what was the
problem they were solving-or thought they were solving?

EmMgenceof~eSaHnftY~$ue

The treaty that guaranteed Mexico 1.5 million acre-feet of Colorado River water annually "from
any and all sources" did not specify its salinity. The salinity of water used for irrigation water
is often critical to agricultural productivity, as high concentrations of salt reduce crop yields and
may preclude the growing of salt-sensitive crops such as tomatoes and lettuce. Because Mexico

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