WSP05341

• File Number: 8278.100
• Description: Title I - Yuma Desalting Plant
• Basin: Colorado Mainstem
• Date: 12/23/1992
• Author: USDOI/BOR
• Title: Yuma Desalting Plant - Alternatives for the Interim Period
• Water Supply Pro - Doc Type: Publication

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range of about 700 parts per million (ppm) to 920 ppm to about 1,340 ppm
total dissolved solids'.

The increased salinity was caused by the discharge to the Colorado River
of saline irrigation drainage (largely Colorado River return flow)
pumped from newly constructed wells in the WMIDD in Arizona and from
upstream reservoir development, which reduced excess flows to Mexico.
Mexico filed a formal protest with the United States in November 1961,
claiming that the increased salinity was a violation of international
law and was damaging crops in the Mexicali Valley. In response, the
United States began modifying WMIDD irrigation drainage pumping and
river operations. In 1965, the United States reached its first salinity
agreement with Mexico, Minute No. 218 of the International Boundary and
Water Commission (IBWC). Minute No. 218 authorized the construction and
operation of the Main Outlet Drain Extension (MODE), which allowed WMIDD
irrigation drainage to be discharged either above or below Morelos Dam,
Mexico's principal diversion structure (see frontispiece map).

However, Mexico continued to press its case, and in August 1972,
President Nixon assigned former Attorney General Herbert Brownell to
find a "permanent, definitive, and just" solution to the salinity
problem. Brownell, assisted by a Federal interagency task force,
studied the problem. Ne90tiations with Mexico proceeded with the
concurrent consultation of the Basin States, acting through the
Committee of Fourteen (an advisory group consisting of two
representatives from each of the Basin States).

After studying several .solutions to the problem, Brownell issued a
report in December 1972 that, among other things, recommended
(1) constructing a desalting plant to treat WMIDD irrigation drainage;
and (2) allowing for a specified differential between the salinity of
the waters arriving at Imperial Dam and the salinity of the waters
delivered to Mexico upstream from Morelos Dam. The President approved
the recommendations, and the Secretary was directed to prepare
legislation seeking authorization for the design and construction of a
desalting plant. For more detailed information on the events see
Appendix A, THE BROWNELL TASK FORCE AND THE MEXICAN SALINITY PROBLEM;
A Narrative Chronology of Events, by Anne DeMarsay.

However, before lending support to any agreement with Mexico, the Basin
States sought certain commitments from the United States. Attachment A
(History and Title I Provisions) contains a list of the Basin States'
concerns. The United States' commitments to satisfy these concerns are
reflected in Minute No. 242 and in Public Law 93-320, Minute No. 242's
implementing legislation.

, Salinity refers to the salt content of solutions containing
dissolved mineral salts, generally measured as total dissolved solids in
ppm.

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