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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Although Brownell's proposed program included lining a portion of the Coachella Canal to
salvage water to replace bypassed drainage from Well ton-Mohawk until the desalting plant began
operating, the states were not satisfied. The Committee of Fourteen objected to his plan because
it did not specify a permanent brine replacement source. The Executive Office agencies once
again proposed the full irrigation efficiency program as an alternative, and it was once again
rejected on the grounds of impermanence. Brownell's fmal report, which became the basis for
Title I of the Colorado River Basin Salinity Control Act of 1974, was delivered to President
Nixon on December 28, 1972.21

Negotiation of Minute No. 242

During early 1973, Brownell's recommendations were under review by the National Security
Council and the Domestic Council. The State Department, meanwhile, convened a small
interagency group, consisting ofOMB, Interior, mwc, and the Mexican Affairs staff to develop
a U.S. negotiating position. Not surprisingly, it was to be based on eliminating the effects of
Wellton-Mohawk return flows on Mexico's treaty deliveries, and would tie Mexican water
quality to that at Imperial Dam. The U.S. would negotiate a salinity differential, not a level.

In mid-April, National Security Advisor Kissinger sent a memo to President Nixon, endorsing
the Brownell report. He also rejected the Executive Office's irrigation efficiency alternative as
not permanent.22 The President officially accepted those recommendations on May 5, and
appointed Brownell as his chief negotiator. Secretary of State William P. Rogers flew to Mexico
City to present the U.S. position to President Echeverria on May 13.

During the summer of 1973, Bureau of Reclamation and IBWC staff developed the formula for
a salinity differential that would serve as the basis for the U.S. offer to Mexico: the U.S. would
guarantee Mexico that its treaty deliveries would have an average annual salinity level no more
than 115 ppm higher than the level at Imperial Dam, plus or minus 30 ppm. These figures were
based on probable variations in Colorado River salinity that would have occurred in the absence
of Wellton-Mohawk drainage. The Bureau completed preliminary studies to configure the
engineering works included in the Brownell proposal, and prepared confirming technical reports.

On June 8, Brownell was accorded Ambassadorial rank. Negotiations took place through the
summer. Brownell and the State Department kept Congressional leaders and the Committee of
Fourteen informed of the progress of talks. Oddly, there was no official disclosure of the
Brownell recommendations until the new Minute was signed.

Mexico accepted the basic U.S. offer, and Minute No. 242, guaranteeing Mexico that the
average annual salinity of its treaty deliveries would be no more than 115 ppm higher than the
salinity of water behind Imperial Dam-plus or minus 30 ppm-was signed on August 30,
1973.23

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