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<br />MEXICAN WATER TREATY
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<br />The unsettled qUe8tion.-The question, in short, remains open: Can
<br />we invoke the drought clause if the reservoirs on' the Gila River
<br />system are dry but those on the Colorado are full and vice verSll?
<br />Can we invoke the clause if the upper basin findsdiificulty in deliV'er-
<br />ing the comp!,ct guaraJ?teed quantity of 75,000,009 acre-feet, 'while
<br />the lower basm reserVOIrs are ful]? If the run-off IS 50 percent but
<br />the consumptiV'e uses in .this country are maintained by drafts on
<br />storage which American irrigation has paid for, can deliveries tu
<br />Mexico be reduced? The Mexican negotiators seemed to have little
<br />doubt on this. Lic. Enriquez stated (E] Nacional, August 8, 1945):
<br />Moreover, in these cases of drought there will be- offered to us daily waters of
<br />the Colorado River by virtue of which 1vlexico has no need for storage works.
<br />The great dams, such as Boulder and Davis, will serve to regulate the delivery
<br />of the waters in the periods of low flow of the river.
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<br />8, FACTORS UPON WHICH THE TREATY IS SILENT
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<br />There are two other blank spots in the treaty, upon which the
<br />legislative history throws very little light:
<br />(a) The existence oj a surplus.-The standard by which existence of
<br />a surplus is to be'determined, entitling Mexico to receive 1,700,000
<br />acre-feet instead of 1,500,000, was left completely open by the treaty.
<br />If the reservoirs are full but the run-off is below norma], what duty
<br />rests upon the American Commissioner? It seems reasonably clear
<br />that this is a matter which the treaty leaves to American determina-
<br />tion, and the direction to the American Commissioner in this respect
<br />ought to be spelled out by Congress before it authorizes any compre-
<br />hensive plan of development of the Colorado River Basin.
<br />(b) Discharge of return flow into Salton Sea.-The .treaty is, com-
<br />p]etely blank as to the quantity of return flow which the Mexican
<br />water users may dump into the closed basin of the Salton Sea, thereby
<br />drowning out lands of the Imperia] and Coachella Valleys. This was
<br />frankly admitted by Mr. Tipton to have been overlooked, The
<br />American negotiators apparently regarded the matter as of little im- ,
<br />portance because only 45,000 or 50,000 acre-feet annually have been
<br />flowin~ from Mexican lands into the Salton Sea. But this is because
<br />diverSIOns through the A]amo Canal have not exceeded 1,200,000 acre-
<br />~eet annually and, more importa,nt, because under American manage-
<br />ment losses were held to very low levels: The treaty specifically
<br />allows Mexico to divert without limit not only 1,500,000 acre-feet per
<br />y~ar, ~ut "any other quanti!ies ~rriviJ?g at .the Mexican points of
<br />dIversIOn" (art. 10), and provIdes m article 17 tha,t-- "
<br />The use of the channelS of th~ international rivers for the discharge. of ;flood or
<br />other exoess waters shall be free and not subject to limitation by either country,
<br />and neither country'shall have any claim against the other' in respect of any
<br />damage:::: caused by such use.
<br />Are New River and Alamo River, through which Mexican return
<br />flow drains into the Salton Sea Basin; "international rivers"?
<br />As to the quantity involved, it will be remembered that the Senate
<br />Committee on Foreign Relations accepted the State Department's view'
<br />(report, p. 4) that return flow from some 3,000,000 acre-feet applied
<br />in Arizona would yield over 900,000 acre-feet per year, If a like ratio
<br />should apply to the 2,000,000 acre-feet which Mexico expects to divert
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