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Arizona Project area. In the Gila River Basin, 6,000,000 acres is the order of magnitude of arable lands suitable for irrigation. Extensive areas of arable land will long remain locked in the reserve vaults of an arid climate, offering a vast potential for future ages when the supply of agricultural lands becomes critical. The productivity of the existing irrigated acreage demonstrates its suitability for profitable agricultural use. The Central Arizona Project is oriented to sustain the economic base and reduce ground-water overdraft; therefore no new lands within the Central Service Zone are being considered for project development. At the present time, agricultural lands are being retired from production in some areas as the ground-water levels fall below the economic pumping depth. Water--At the start of the present cultural era in the Gila River Basin, the surface-water resources were more than adequate in volume to supply all the demands. As development increased, natural flows were overappropriated and storage and regulation became necessary to provide an adequate supply. Regulation of the Salt River started in 1910, before completion of Roosevelt Dam in 1911. Other reservoirs have added to the control, including Coolidge Dam on the Gila River in 1928 and Bartlett Dam on the Verde River in 1939. With practically all surface water being controlled and put to beneficial use, further agricultural expansion of the area has continued in recent years by development of the ground-water reservoirs for large scale irrigation uses. The surface-water supply, averaging 1,460,000 acre-feet annually, and current ground-water withdrawals of 4,300,000 acre-feet, provide for the present demands. Ground-water withdrawals greatly exceed the natural recharge and water levels are dropping rapidly. 4Epson Perfection 4870 Photo, 400 dpi, 8 bit, 14,166,016 byte