468. Letter From Secretary of State Rogers to Secretary of Foreign Relations Rabasa1 2

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Dear Mr. Secretary:

I very much appreciated your visit of June 28, and the opportunity it gave us to discuss our mutual problem arising from the salinity of the Colorado River waters.

Recognizing the importance of this problem, and in response to your President’s letter, President Nixon asked his principal advisers in this matter to give it immediate attention. We have again and in detail conferred with soil and water scientists, with officials of the Colorado River Basin States, and within the United States Government.

While I regret that we cannot accommodate the latest proposal of your Government, I am pleased to inform you our efforts have resulted in a further United States proposal, which I now offer as a basis for a new six-year salinity agreement. You will readily recognize its greater benefit to Mexico over Minute 218.

This proposal would at once attain the permanent and effective solution that both our countries seek to the problem arising from the high salinity of Wallton-Mohawk water. Beginning with the first year of the new agreement the United States would take measures to ensure that the waters of the Colorado River delivered to Mexico include only such drainage waters from the United States irrigated areas below Imperial Dam as would, with other waters, result in normal quality drainage from those areas, thereby further reducing the saline content of the water delivered to Mexico.

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To implement this proposal, the United States would provide each year quantities of water from the Colorado River above Imperial Dam and from ground-waters underlying the Yuma Mesa, in substitution for equal quantities of the Wellton-Mohawk drainage waters, to the extent and for as long as necessary to assure that the resulting salinity of the combined drainage and substitution waters in Mexico’s scheduled deliveries is not more than that of normal drainage waters. Such water would be of the salinity that would result from good irrigation and drainage practices, and the quantity of salts discharged to the river below Imperial Dam would be not more than the minimum essential for the use in my country of its share of the waters of the Colorado River.

The resulting quality of the water delivered to Mexico would be the same as if the current problem, resulting from the abnormal salinity of the drainage from the Wellton-Mohawk project, had never arisen. The proposal would be an improvement over our prior proposal which would not have resulted in normal deliveries until the third year of an agreement.

As part of the new agreement I propose, the United States would agree to the Mexican desire to include a commitment, that the two governments discuss questions relative to the interpretation of the treaty during the term of the new Minute in an effort to reach some further understanding before the end of that period. It would be understood, of course, that such a commitment would not preclude the two governments from solving any new practical problems that may arise in regard to the quality of the Colorado River waters by agreement on practical measures as we have in the past.

As you know, the United States is undertaking an extensive and costly program with the objective of protecting the quality of the Colorado River water in the future for the benefit of Mexican as well as its own water users. The fulfillment of this objective, together with your Government’s acceptance of our proposal, would assure Mexico 1.5 million acre-feet per year of useful waters well into the future.

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Ambassador McBride will tell you of the special effort we have made in preparing this proposal to provide Mexico with the best water we can without sacrificing the vital water resources of our own people. He will provide technical memoranda outlining the proposed operating provisions as well as commenting briefly on Mexico’s most recent suggestions.

I would urge your Government to give our proposal its most careful consideration and sincerely hope that you find it acceptable as the basis for a new agreement.


William P. Rogers
  1. Source: National Archives, RG 59, Central Files 1970–73, POL 33–1 MEX–US. No classification marking. In telegram 4238 from Mexico City, July 27, the Embassy reported that it had delivered the new proposal to Echeverría and Rabasa, both of whom agreed to carefully study it, but made no commitments. (Ibid.) Rabasa’s proposal is published as Document 467.
  2. Secretary of State Rogers informed Foreign Secretary Rabasa that the U.S. Government could not accommodate Mexico’s proposed 6-year agreement for dealing with the Colorado River salinity issue, but offered a counter-proposal.