Foreign Relations of the United States: Diplomatic Papers, 1942, The American Republics, Volume VI
The Mexican Ambassador (Castillo Nájera) to the Secretary of State
The Ambassador of Mexico presents his compliments to His Excellency the Secretary of State and, in compliance with instructions received from his Government, takes pleasure in transmitting to him a memorandum in connection with the Department’s memorandum sent through the intermediary of Mr. Duggan on March 27, instant. Attached thereto is a report on the American proposal concerning the Rio Bravo prepared by the Technical Section of the Department of Foreign Affairs of Mexico.
The Ambassador of Mexico thanks His Excellency the Secretary for the attention which he may be good enough to give this matter and takes the opportunity [etc.]
Proposed Treaty for the Distribution of the Waters of International Rivers Between Mexico and the United States of America
mexican counterproposal relative to the waters of the rio bravo
With reference to the Department of State’s memorandum of March 27 instant, referring to the distribution of the waters of the Rio [Page 554] Bravo, the Government of Mexico declares forthwith its full willingness to study and settle, jointly with the Government of the United States, the problems presented by the distribution and utilization of the said waters at the same time that the conversations initiated with regard to the Colorado River are carried on.
It is well to point out that a simultaneous consideration of all aspects of the best utilization of the Rio Bravo and the Colorado establishes a solid basis for arriving within the near future at an understanding between the two countries which will definitively solve this complex matter. It is possible to forecast a satisfactory result in view of the fact that, in addition, the conversations between the two Chancelries are guided by a sincere wish to obtain the best complete utilization of the international streams to the benefit of the two countries and a distribution of their waters in a way adequate to the present and future necessities of each of them and in a manner which will entirely prevent or will proportionately and fairly divide the damages resulting from an insufficiency of the volume of the rivers.
From a careful reading of the aforesaid memorandum of March 27, the Government of Mexico has become convinced that the two Governments are entirely in agreement with respect to the greater part of the points to which the said document refers and that these, certainly, are the fundamental aspects of the problem of the distribution of the waters of the Rio Bravo between the two countries.
In fact, it is well known that in order properly to conserve the waters of the aforesaid river, to the advantage and for the use of both countries, constructions for storage and to draw off water are required on the principal stream at those points where a satisfaction of the needs of the lands which must be irrigated is best to be achieved, and that attention must be given both to the requirements of the American bank, which needs hydraulic works upstream from the confluence of the Rio Bravo and the Salado River, and to the requirements of Mexican lands, which need storage and run-off constructions a little below the confluence mentioned. Only, it is necessary to add, to this point of agreement, that all the works—whether they directly benefit the United States or whether they redound preponderantly to Mexico’s advantage—must form a coherent whole which will bring benefits to both countries, since together they will serve to store and handle efficiently the volume of the river’s flow, a result which it would not be possible to achieve with any one of the works individually.
It is obvious that the number, approximate location and capacity of the international storage and run-off dams must be agreed upon in the Treaty, these points being subject to the variations which are decided upon, by common agreement, by the two Commissioners. It is also considered just and equitable that the costs should be prorated between the two countries in proportion to the benefits which [Page 555] each of them will receive from the construction of the works, account being taken of the utility thereof, both from the point of view of defense against floods, and from that of irrigation.
The Government of Mexico concurs with that of the United States of America in considering that the physical character of the Rio Bravo valley prevents a distribution by equal parts of the principal stream at specified points of its channel (although it does insist on a total distribution in equal parts of the general flow which the said principal channel carries and conducts). Accordingly, it is considered advisable that the volume assigned to each country be its property and under its control in each of the international storage dams, that the countries may thence run them off in the most advantageous manner and the greatest flexibility and independence in the uses effected by each be achieved.
The above agreement implies a common opinion as to the right to use the channel of the river to transport the water assigned to each country from the storage receptacles to the points of intake or run-off most convenient to the riparian users. In addition, as stated in the Department of State’s memorandum under reference, the system requires an efficient appraisal service and the necessity of keeping an account of the water in each storage receptacle, to the end that the amount to be accredited to each country may be determined, losses by evaporation and waste being charged in proportion to the amount stored which has been credited to each country.
Among those most important general points—on which the existing agreement between the two Governments establishes an adequate system for the best utilization and distribution of the waters of the Rio Bravo—there is only one important discrepancy, with certain incidentals, concerning which a fair arrangement can be reached.
The Government of the United States proposed that certain Mexican affluents of the Rio Bravo furnish a volume of one million acre-feet annually for the exclusive use of the American bank. This contribution should be liquidated and completed in cycles of three years. It considers that, with such volume, plus the total contribution of the American affluents and fifty per cent of the flow of the principal channel (not coming from evaluated affluents), the United States would have its needs met.
The Government of Mexico regrets that it is unable to accede to the American proposal in consideration of the fact that the volume of the Mexican affluents assigned to meeting the aforesaid allotment is so low that in dry years Mexico would not be able to comply with its obligation without decreasing uses already existing in the valleys of these affluents. Furthermore, a series of dry years would leave Mexico, when it made the triennial liquidation, with a debt which it would be very difficult to redeem in the future. In order to obtain [Page 556] a complete regularization of the current of those affluents, the Government of Mexico would need to construct very expensive works which are out of proportion to the utility which would be obtained from them. In view of the foregoing, it does not seem fair for Mexico alone to endure the injuries resulting from lack of precipitation. Nor does it seem fair that, in order to meet such certain contingencies, the valleys of such affluents should be deprived not only of any future development, but even of their present uses.
The Government of Mexico, in exchange, proposes a distribution by equal parts of the general flow of the Rio Bravo, and—as the Mexican affluents furnish this general flow with more than double the volume coming from American tributaries—it is obvious that, in the fifty per cent corresponding to the United States of America there are included: a) all contributions by American affluents; b) fifty per cent of the flow coming from non-evaluated, transitory and small sources; and c) a little more than a fourth of the total flow which reaches the Rio Bravo from Mexican affluents.
Accordingly, in abundant and in normal years, the amount thus formed will be equal to or greater than that desired by the Government of the United States of America and only in dry years will it be less; but it will be less in the same proportion as Mexico has the water corresponding to it reduced. With this procedure, the two countries will feel the injuries resulting from droughts fairly and proportionately. Furthermore, the international storage dams on the channel of the Rio Bravo will be able to regularize the utilization of the river for the purpose of meeting the deficiencies in the dry years, provided that a great many consecutive periods of drought do not occur.
The proposal of the Government of Mexico is based on the fact that available studies indicate that present uses and possible future uses in the valley of Mexican and American affluents will not be able completely to exhaust such streams and, accordingly, there will always be a remainder which, united to waters from freshets, returns, etc., which will be stored in the international dams, will be sufficient to furnish water at the run-offs made in those international works to meet the needs of both banks. Under the foregoing conditions, the amount corresponding to American riparian lands will be approximately what the Government of the United States of America seeks in proposing a fixed quota, furnished by the Mexican affluents.
The said proposal may be supplemented by the possibility that, upon the approval of the two countries, each of them may consume in a specified stretch of the river or at a certain storage dam or group of dams a greater volume than corresponds to it, provided that the difference in excess will be made up to the other country in another stretch or in one or more other dams.[Page 557]
Notwithstanding the foregoing, if the Government of the United States of America should not consider that the flow of the principal channel of the Rio Bravo and its affluents is sufficiently great for the United States to obtain a volume equitably adequate to its needs through a distribution of the total waters by halves, or if it considers that the uses of the affluents may in the future sensibly diminish the volume received by virtue of the distribution by halves, the Government of Mexico agrees that, when the proposed Treaty is signed, the corresponding Commissioners may be authorized to make a joint hydrological study which will include in its entirety the principal stream of the Rio Bravo and that of its affluents for the purpose of establishing regulations to the effect that available waters be distributed in proportion to the legitimate needs which exist or may exist in the two countries.
Finally, the Government of Mexico begs to draw the attention of the Department of State to the present situation in the Juárez Valley. To begin with, the Government of Mexico does not feel that there is any reason or ground for considering the Juárez–Cajoncitos section of the Rio Bravo as a mere water-conveying canal or an American affluent, inasmuch as the said section has not lost its character of an international river boundary. In addition, the table of water delivery to Mexico is contrary to the meteorological and agronomical characteristics of the present time in the aforsesaid Juárez Valley and the volume of water actually utilizable from the channel which the United States of America delivers at the Acequia Madre in Ciudad Juárez has in reality decreased through the increase in the alkalinity of the water. The Government of Mexico hopes to receive from the Government of the United States of America a friendly and equitable understanding of these partial problems presented by the utilization of the Rio Bravo, for the purpose of obtaining a final and adequate solution of this question in its entirety.
A brief technical exposition which gives the bases for the proposals contained in this memorandum is attached.78