Memorandum From the Mexican Ministry for Foreign Affairs 16


Distribution of the Waters of the Colorado River

The Government of Mexico has given most careful attention to the Memorandum of the Department of State dated November 4, 194217 relative to distribution of the waters of the Colorado River.

Before commenting in detail concerning each of the points contained in the Memorandum under reference it is pertinent to analyze certain fundamental discrepancies which may perhaps explain the little progress made to date in the negotiation of a water Treaty between Mexico and the United States of America.

At the outset the Government of Mexico reiterates its stand of dealing uniformly with the problems arising from the utilization of the waters of the Bravo18 and Colorado Rivers since, as will hereinafter be made manifest, the application of differing standards to the [Page 597] two international currents mentioned would lead to inequitable solutions.

Secondly, it cannot accept that the theory of a supposed right based upon priority of use should become a fundamental rule to decide the problem of distribution of the waters of international rivers, and it also considers inadmissible that the proposal of the United States of America for the delivery of waters of the Colorado River to Mexico should base itself exclusively upon compliance with and protection of Mexican uses prior to the completion of Boulder Dam. The reasons for the foregoing attitude derive from the fact that if in the case of ownerless things or things over which there is no established right, the mere occupation and priority of use thereof can produce the erection of a right over such things, this does not apply as regards those properties concerning which there is a right prior to any occupation or utilization; this latter right implying the faculty, precisely, of using or utilizing the thing as occasion may permit, or at the will of the holder thereof. In the case of the waters of the Colorado and Bravo Rivers Mexico has the right to their use and utilization, derived from existing Treaties between the two countries and from the norms of International Law which regulate the joint relations of neighboring countries with relation to international rivers flowing between them and, therefore, this right is prior, principal and independent in relation to any act, and against it there can prevail neither occupation nor priority of use. Furthermore, the thesis expressed by the Department of State does not appear to be very fair since, if it were applied in the case of the Bravo River it would produce the conclusion that the United States of America shall receive only the waters indispensable to satisfy the needs of utilization in the Brownsville Valley prior to the construction of hydraulic works on the Conchos River;19 which, having regularized the principal supply of water flowing in the Lower Bravo River and having supplied the most permanent stream in the dry season, made possible the greater part of present uses in the American region mentioned.

Lastly, neither can the Government of Mexico admit that the question be reduced exclusively to determining what would be the volume of excess water in the Colorado River after satisfying all present utilizations and all projects for future uses in American territory; so that Mexico would be constrained to receive only the excess volume which would not be utilizable for the United States of America. Application of this principle to the Bravo River situation would result in the conclusion that Mexico would be authorized to utilize all the current of the Mexican tributaries, even to the employment of their waters—especially those of the Conchos—in tappings outside of their [Page 598] basins; the Lower Bravo users to be content with the volumes which might be left over even though thereby many of the present utilizations on the American side of the Lower Bravo River might be rendered impossible. The Government of Mexico considers that both situations are absolutely unfair and reiterates its opinion that the waters of international rivers must be distributed among the riparian countries in proportion to the areas susceptible to irrigation in equality of hydraulic conditions; in such a manner that if there should be insufficient water to satisfy them all there be mutually eliminated projects which present the same characteristics of high cost and difficulty of realization. It is not clearly seen why, with the object of fixing American needs to the waters of the Colorado, there are considered future projects of costly execution and extractions from the basin and, on the other hand in evaluating the demands of Mexico there are eliminated not only easier realizations and its urgent needs for the immediate future, but even projects under development and even a certain number of present utilizations.

From the above, it is to be hoped that the situation with respect to the Colorado River be fixed with the same spirit of fairness and equality with which the problems of the Bravo River are being viewed.

Going on to a detailed consideration of the various technical questions raised in the Memorandum of the Department of State to which reference is being made, the principal points of discrepancy are enumerated below:

The Government of Mexico affirms that it is by no means bound by the “Colorado River Agreement” executed among the American States bordering on the basin of the river mentioned, and the “Federal Law Regarding the Boulder Canyon Project”.20 But if endeavor were made to apply the said agreement, it would be in order to recall one of its stipulations which disposes that—in case a Treaty with Mexico is signed and that the water thereby to be delivered to our country should exceed the available excess in the hydraulic system of the river—the amount lacking would be supplied in equal parts by the two groups of States in which the general basin of the Colorado in the territory of the United States of America was considered divided.
Neither the amount of 19,744,000,000 cubic meters (16,000,000 acre-feet) fixed as initial distribution to be used for beneficial purposes in the United States of America, nor the amount of 2,468,000,000 cubic meters (2,000,000 acre-feet) which Mexico desires to receive, represent the maximum volumes which might be utilized in the two countries. It is borne very much in mind that by tapping out of the basin of the Colorado River, by carrying out pumping irrigation projects at [Page 599] very high rates and by irrigating very poor quality land volumes in excess of double the river’s total current could be consumed. The problem, therefore, hinges on directing the question within the applicable norms of International Law and fixing equitable distribution figures, bearing in mind the proportion between the possibilities of comparable agricultural utilization existing in the two countries.
It is admissible that the group of States of the lower American basin will have to use 789,760,000 cubic meters (640,000 acre-feet), more than the assignment fixed for them by the respective Agreement;21 but on the other hand, there would be a considerable leftover in the rate fixed for the States of the upper basin. In effect, in accordance with the data in possession of the Mexican technicians, this upper basin would be unable to use the 9,255,000,000 cubic meters (7,500,000 acre-feet) assigned to it by the Colorado River Agreement, so that there will be a considerable excess, which added to the 2,468,000,000 cubic meters (2,000,000 acre-feet) difference between the total initial current of 22,212,000,000 cubic meters (18,000,000 acre-feet) with that of 19,744,000,000 cubic meters (16,000,000 acre-feet) distributed in the said Agreement, results in an available volume which we consider sufficient to take the 789,760,000 cubic meters (640,000 acre-feet) which, according to the American memorandum, are lacking in the lower basin, the losses by evaporation in the basins, the 2,468,000,000 cubic meters (2,000,000 acre-feet) of Mexican dotation and there would still be an excess for future uses in normal periods.
The hydraulic studies made in Mexico—which took into consideration periods of scarcity, losses by evaporation in basins, et cetera, since it would be inconceivable that a serious hydraulic study should overlook these factors—show that even in the periods of ten or more years of scarcity, Mexico can be supplied with the 2,468,000,000 cubic meters (2,000,000 acre-feet) per annum. In those extraordinarily scarce years when it would not be possible to make such delivery, Mexico would have no objection to a reduction of its portion in a percentage equal for all utilizations of the Colorado River.
The data on which the Mexican study was based include the year 1938 and are, therefore, recent. Their degree of exactness is demonstrated by the fact that in that study the average initial flow of the river is considered at 22,212,000,000 cubic meters (18,000,000 acre-feet) which coincides with the figure cited as the most recent in the Department of State’s Memorandum.
The average flow of 17,893,000,000 cubic meters (14,500,000 acre-feet) in the scarce period of 1930–40 cannot be taken as a basis to maintain that there is no water available, since in a hydraulic study, when the river under reference contains a large storage dam, such as Boulder Dam with a capacity of more than 38,254,000,000 cubic meters (31,000,000 acre-feet) a scarce cycle is favorably modified by the original storage the function of which is precisely that: supply the deficiencies of the scarce periods with water stored in the abundant periods. The period from 1920 to 1929 was an excessively abundant [Page 600] one, therefore the beginning of the scarce period would surely have found the dam full and this would have made it possible to supply the deficiencies of the scarce years. At any rate this matter should be the subject of a joint study by technicians of the two countries.
It is possible that only in three of the eleven years comprised from 1930 to 1940 the amount of 2,468,000,000 cubic meters (2,000,000 acre-feet) could have been furnished to Mexico, after supplying the projects under construction in the lower American basin; but it is clear that this amount could have been furnished without restricting those developments by using the excess allowed to the States of the upper basin which could not have been able to consume it entirely.
The Government of Mexico does not accept that the problem under study be reduced to determining what the volume of water used in Lower California was before 1935. Nevertheless it is good to observe that the cultivated surf ace in Mexico from 1925 on was affected more than by hydraulic factors, by the economic conditions which at that time were applicable throughout the world and which also affected cultivated surfaces in the United States of America. In Mexico from 1925 to 1929 surface remained practically the same. From 1930 to 1933 the world depression which considerably lowered the price of cotton, the only cultivation at Mexicali, caused the cultivated area to be greatly reduced. From 1934 on in spite of this having been the year of greatest scarcity, an improvement in the price of cotton and the establishment of other crops, such as wheat, contributed to the rapid increase of the area cultivated.
It is too venturesome to assert that the increase in the use of Colorado River water in Mexico, beginning with 1935, was due to the construction of the hydraulic system of Boulder Dam. In accordance with the conditions under which the concession of the Cia. de Terrenos y Aguas de la Baja California, S. A.,22 was operated, the area cultivated in this portion of Mexican territory before the construction of the dam had not reached its maximum development and, further, the foregoing point has already outlined the economic factors which gave rise to the extension of irrigated surfaces after 1935.
On the other hand, there has been borne very much in mind the benefit resulting for Mexico upon receiving the volume of water regularized by the hydraulic works effected in territory of the United States of America; therefore the irrigation of a considerable surface of good land has been abstained from, susceptible of easy and economic cultivation, and its pretension has been limited to 2,468,000,000 cubic meters (2,000,000 acre-feet). Unquestionably, if the irrigable surface, the necessities, and the absolute right of Mexico should be attended, it would be necessary to fix a volume much greater than that mentioned, derived from the irregular and uncontrolled flow of the Colorado River.
The volume offered by the Government of the United States of America, of 1,419,000,000 cubic meters (1,150,000 acre-feet) is insufficient to assure even the present utilizations being effected in Mexican territory in Lower California. As has already been said, the amount of 2,468,000,000 cubic meters (2,000,000 acre-feet) is much [Page 601] less than the volume to which Mexico would have a right; it has been fixed considering the lower limit of Mexican needs, a fair division of the waters of the river and the control and regularization supplied by the American works. Similarly, due consideration was given to the fact that this volume of water can be furnished by the United States of America the greater part of the time without important sacrifices in its utilizations and, for the extraordinarily scarce cycles which imply insufficiency of the available flow in spite of the storage systems, Mexico is willing to a reduction of its allocation by means of a proportional pro rata of the water between the two countries.

In view of the above, and by virtue of the fact that the Bravo and Colorado Rivers problem requires urgent and undeferable decision the Government of Mexico begs to suggest to that of the United States of America that the matter be placed entirely in the hands of the respective Limits Commissioners23 with instructions to the effect that existing differences be mutually decided within a brief period and that they determine with precision the data upon which they may not be able to agree.24 In the meantime the two Chancelleries could study an amicable and fair procedure for the mutually satisfactory adjustment of the discrepancies between their Limits Commissioners.

  1. Transmitted to the Department by the Chargé in Mexico with his letter to the Adviser on Political Relations (Duggan), February 19, 1943, infra.
  2. Foreign Relations, 1942, vol. vi, p. 561.
  3. Mexican name for the Rio Grande River.
  4. A tributary of the Rio Grande River in Chihuahua state, Mexico
  5. The Boulder Canyon Project Act of 1928 (45 Stat. 1057) provided congressional approval for the Colorado River Compact, an agreement among the Basin States by which the waters of the Colorado River were apportioned between States of the Upper Basin and those of the Lower Basin.
  6. The Compact assigned 7,500,000 acre feet per year to the Upper Basin and the same amount to the Lower Basin, with the right, however, to increase this amount by 1,000,000 acre feet per year.
  7. A subsidiary of the Imperial Irrigation District of Southern California. The latter was a public corporation which operated all the facilities involved in carrying water from the Colorado River to the Imperial Valley.
  8. International Boundary Commissioners, L. M. Lawson and Fernández MaoGregor.
  9. In its short reply to this memorandum, dated May 15, 1943, the Department of State agreed that a determination of sound assumptions should provide a basis for a workable formula, and stated that therefore it was instructing its Boundary Commissioner to confer with the Mexican Boundary Commissioner on technical questions to which solutions were necessary before treaty negotiations could begin (711.1216M/2253).