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I> ecutive Order, dated February I, 1917, re-established the Schuk Toak District as part of the Sells Papago Reservation. The'Tucson metropolitan area, population 531,000, is one .of the largest communities in the world that is solely dependent upon groundwater for its municipal and industrial water supply. That water supply comes from several well fields located in the Santa Cruz and A vral Altar Valley basins. These two basins also supply water used by copper mines operat- ed by the Anaconda COInpany, Amax Copper Mines, Inc., the Pima Mining Company, the American Smelting and Refining Company and the Duval Copper Corporation Mines sited located adjacent to the San Xavier Reservation produced 293,098 metric tons of copper In 1980; 24.8 percent of the total production of the United States in that year. Other significant water users in eastern Pima County include the Cortam-Marana Irrigation District, the A vra Valley Irrigation Dact and the Farmers Investment Company. ~ assembled by the Water Resources Coordination Committee (WRCC) a voluntary association of the major water users in eastern Pima County, indicate that consumptive use of groundwater pumped from these basins totaled 317,186 acre feet 1 in 1980. Pro- jected consumption will exceed 400,000 acre feet for the year 2000 and 500,000 acre feet in the year 2030.1 . The data also indicate a serious imbalance between existing supply and demand in these basins. Current demand for water ex- ceeds renewable supplies by a ratio of more than four to one. The estimated overdraft of groundwater in 1980 was 225,706 acre feet.' This imbalance has resulted in significant, long term declines in local grl!undwater levels. There is increasing concern that further declIne In water levels will result in increased pumping costs, re- duction in well capacity, diminished water quality and increased risk of land surface subsidence. Recognition of the gravity of the groundwater overdraft problem has le~ w~ter users in Tu~son and eastern Pima county to imple- ment SignIficant conservatIOn measures on a voluntary basis. 'j(lcultural users have greatly improved their irrigation effi- CI by land leveling, ditch lining, and installation of pump-back sy s. Further decrease in agricultural water use is anticipated through municipal and industrial development of currently irrigat- ed land. According to data assembled by the WRCC, stich develop- ment could reduce the amount of water consumption per acre by 75 percent. 1 The mines have also realized considerable conservation through a variety of methods, such as recirculation of water, water recovery from tailings areas, use of settling methods prior to disposal of mine waste, reduction of water levels in flotation cells and utiliza- tion of natural seepage. Municipal customers of the City of Tucson have, through volun- tary conservation programs, reduced their average daily per capita demand from 205 gallons in 1974 to 140 gallons in 1979. The signifi- I Statement of the Water Resources Coordination Committee to the Water and Power He-' sources Subcommittee of the U.S. House Committee on Interi.or and InsuJar Affairs. Mar 13 1981. . . I; 1033 :J cance of this reduction is apparent by comparing this consumption rate with use in other major cities in the Southwest: Pernzpita demand 173 220 310 179 189 140 Tucson......................................................... ................ ...............-...... , The Central Arizona Project, a Federal Reclamation Project that will bring Colorado River water from Parke..- Dam a~ Lake H~vasu, to central and southern Arizona, WIll prOVide additIonal rehef for the overdrawn groundwater basins in eastern Pima County. Dehv- ery of water to Tucson and southern Arizona is expected in .1989. Agricultural, mining and industrial water users who contract for CAP water will be required to reduce groundwater pumpmg on an acre foot for acre foot basis: for every acre foot of CAP water used, the subcontractors must reduce their groundwater pumpmg by an acre foot. . Strict management of groundwater resources is currently being implemented by the Arizona Department of Water Resources pur- suant to a groundwater code enacted by the State legislature in 19802. ..' The Code designates four geographIc umts as Active Manag... ment Areas (AMA). Within an AMA all present users of ground- water must file for a certificate of grandfathered pumping rights in order to perfect their right to pump groundwater. Only acreage Ir- rigated any time during the 5 years prIOr to enactment of the Code may be irrigated. New uses ,:"i11 be allowed .only pursuant to State permit. Moreover, the Code Imposes hmltatIons on the transporta- tion of groundwater between sub-basms or away from any AMA. The Tucson Active Management Area corresponds to the geo- graphic boundaries of the Upper Santa Cruz Valley Basin and the Avra/Altar Valley Basin. The goal of the Tucson AMA IS safe yield, that is, a balance between recharge. and WIthdrawals, by Jan- uary I, 2025. 0- -...J c.o .t:. City: El Paso................... .................................. ................................................. Phoenix.................................................... ................................................... Las Vegas.................................................... ............................................................. San Diego ................................................ .....n................................ Reno ....................................................n........................... ........................................ i Ariz. Rev. Stats. Ann. 45 ~ 4(~H198Q).