Appraisal Report Central Arizona Project

Document: "Appraisal Report Central Arizona Project-Chapter II", January 1962, page 15the soils tend to be coarser, more gravelly, and have less effective soil depth. The lime horizon is usually leached to 20 inches or more in these soils. Natural drainage is usually excellent and these soils respond well to irrigation. The alluvial stream-deposited soils along the river bottoms are also important to irrigation in the area. In places, these bottom areas are typically mellow and pervious throughout, but locally are influenced by high water tables and high salinity conditions. Reclamation by drainage and leaching, where necessary, has proven to be economically feasible. Present Land and Water Use It is estimated that there are approximately 1,162,000 acres of land developed for irrigation in the Central Arizona Project area, of which an average of about 880,000 acres were in production during the 5-year period 1955-60. The irrigated acreage fluctuates from year-to-year in accordance with available water supplies. In general, the acreage of developed lands increases somewhat from year-to-year as additional lands are being continually developed for irrigation wherever isolated groundwater supplies can be found. Some 280,000 acres of developed lands, currently out of production, include lands temporarily idle because of deficient surface-water supplies, and also lands which have been abandoned as pumping costs have increased beyond the point of diminishing returns as a result of falling ground-water tables. Table 1 shows the estimated urban population and agriculturally developed acreage within the various hydrologic study areas. As indicated by table 1, the major urban centers have developed within the Maricopa and Santa Cruz hydrologic study areas. The principal city in 15Epson Perfection 4870 Photo, 400 dpi, 8 bit, 1,001,594 byte