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Show CHAPTER II 35 would also be the first time irrigation water, forming a portion of an irrigation district's entitlement, would be used for nonirrigation purposes and the quantity of irrigated land thereby reduced. The necessary State and Federal approvals of construction of the nuclear plant had not been obtained at the end of 1978. B.9 Article V Reports under Decree in Arizona v. California and Return Flow Credits As "watermaster" of the Colorado River pursuant to the Supreme Court Decree in Arizona v. California, it is the responsibility of the Secretary of the Interior, through the Bureau of Reclamation, to keep records of all users of Colorado River water in Arizona, Nevada, and California. In compliance with Article V of the Decree an annual report is prepared by the Bureau showing total Colorado River water released through regulatory structures controlled by the United States, diversions, return flow of such water, and consumptive use of such water stated for each diverter, and each of the States of Arizona, California and Nevada. This is done for each user agency having contracts with the United States as well as those who do not. This includes both surface diversions and returns as well as ground-water pumping. Pumping from the underground is included only for those wells located in the flood plain of the Colorado River between the toes of the slopes on either side of the Valley. It may become necessary in the future to include also those wells outside of the flood plain which, as a result of pumping, reverse the slope of the water table so that water flows from the river to the wells. The Annual Report for calendar year 1977 appears as Appendix 201. There are also undetermined amounts of unmeasured return flow reaching the Colorado River by means of underground flow from aquifers underlying water use areas. A task force on ground-water return flows to the lower Colorado River, consisting of State and Federal members, was organized in 1970 to provide advice and guidance to the Bureau of Reclamation and to the Geological Survey which are jointly conducting a program to determine the location and amounts of these unmeasured return flows. When such quantities are determined, it is anticipated that these amounts will be credited to the affected users and States in making the consumptive use computations. B.10 California Water Use In 1975, 1976, and 1977, the major California water contractors consumptively used the following quantities of Colorado River water: 1975 1976 Metropolitan Water District Palo Verde Irrigation District Reservation Division - Indian Unit Reservation Division - Non-Indian Unit Imperial Irrigation District Coachella Valley County Water District 778,495 790,857 449,486 392,220 42,449 43,941 46,903 49,958 3,070,974 2,876,984 570,987 524,801 1977 1,276,891 acre-feet 435,062 acre-feet 34,151 acre-feet 43,854 acre-feet 2,772,062 acre-feet 508,635 acre-feet The total water use for the above and all other users during 1975, 1976, and 1977 was: 1975 1976 1977 5,496,007 512,302 4,983,705 5,242,324 535,730 4,706,594 5,626,818 acre-feet of diversions 514,140 acre-feet of measured return flows 5,112,678 acre-feet of consumptive use |
