Chapter 1: Summary of "The Law of the River"

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26 UPDATING THE HOOVER DAM DOCUMENTS of In the actual operations under the Operating Cristanhiannual , the accumulation 1 e mulation of602(a)storage is not the the numerical value for Section 602(a) storage by g criteria governing the release of water during the current year." In 1975 the first formal 5 -year review of the criteria was made, but after receipt of comments, the Secretary announced their continuation without change. The Operating Criteria are elaborated on in Chapter VII. Q. Mexican Salinity Problems s generally within 100 parts per million (p /m) of the water No problems arose with regard to water deliveries to Mexy o between 1945 and 1961 since the salinity o the waters delivered at the Northerly Boundary S at Imperial Dam, the last major diversion point for users in the United States. In 1961 two unrelated events occurred which affected Gi a 5alinity of the Mexican P oject authorized in water 947 l and i whose t con Wellton- Mohawk Irrigation and Drainage District (part wells wh struction was completed in 1952) commenced oper below Dam but bove the Mex- line waters with approximately 6,000 p/m into the Colorado RiverLake ican diversion point. in Second, there was a sizable reduction in rivers at Glen M Canyon Dam l in e tthe Upper Basin in C order to store Mead in anticipation of the closure of the gate e of water in Lake Powell. This increased the salinity f to 1 Sat delive in 962. Mhe salinity r e adings a 800 p /m in 1960 to nearly 1,400 p/m in 1961 a times exceeded 2,000 p /m.• l waters d to it and In November 1961 Mexico strongly object ook t t lacelto h resolve e matter. The ti li negoons resulted i n negotiations between the two governments P Minute No. 218. O:1 Minute No. 218 On March cal 22 1965, a 5 -year agreement, designated Minute No. 218, was concluded el rights. Under it f waters reaching Mexico, with each side reserving measures to reduce the salinity o the United States took the following actions at a cost to it of $12 million: (1) Construction and operation of an ext eno bypassed at Morelos Dam at Mexico's option, received Wellton- Mohawk drainage water could either b above Morelos Dam where it would be n l d wi h Wellton Mohawk Division ch owed selective Colorado River waters (2) Construction of additional drainage in te assin Wellton- Mohawk pumping of the most saline drainage waters at times when Mexico wound of higher quality ground water drainage waters; i.e., during the winter months, and allowed the pumping at times when Mexico would be using Wellton- Mohawk water. (3) Replacement of a portion of the bypassed Wellton- Mohawk drainage waters —which resulted in the release of approximately 40,000 acre -feet per year of "stored water" from Imperial Dam in excess of the 1.5 maf per year guaranteed by the Treaty: taken by the United States, the quality of the water delivered to Mexico was im- Under the above measures proved from about an average of 1,500 p 1970 oblemsro/m in 1962 d provided d for in 1971. after the Minute No. 218 was to expire in November consideration the Mexican officials did n not e want to review of the conditions which gave rise to the p However, power in Mex- enter into a long -term agreemenNo. 218 the efor9was since a new extended for 1-year ti per od assuming p supported ico in December 1970. Minut Negotiations commenced in 1971 ose i d a new Minute which would have provided Colorado t River wat er to -- - --- by the C of- Fourteen, pr o p _- - Mexico having the me salt concentration as al Dam, exisaltJbalance W i.e., that onn of salt in drainage projects in the United States below the Imp lied to these lands below waters delivered to Mexico would not exceed the tonnage of the salt in the water app