Pacific Southwest Water Plan August 1963

Document: "Pacific Southwest Water Plan- Corrected to 8/19" Chapter II, August 19, 1964, page 9Arizona--Irrigated areas along the river in Arizona include the Yuma Project, the Wellton-Mohawk Project, the Gila Project, Indian projects along the river in the vicinity of Parker and Blythe, and others including unauthorized diversions. These adjacent-to-the-river developments have not been impaired in development and have not been short of water. However, the Indian developments have been slow in expanding, for lack of financial assistance to construct diversion and storage works. Other small tributary basins adjacent to the river have experienced shortage in water supply. This is particularly true in the vicinity of Kingman, which is dependent upon local ground-water supplies. This area and other similar small basins adjacent to the river are now experiencing ground-water overdraft, which will continue until additional supplies are made available. A portion of Arizona's Colorado River water entitlement could be made available to these areas by pumping directly from present or proposed reservoirs in the vicinity. The Gila River Basin above Painted Rock Dam is the area of primary development. This area encompasses the large metropolitan areas of Phoenix and Tucson. Dependable surface-water flows available to this area have been completely used for many years. Municipal and industrial expansion is being made at the expense of a continuing depletion of ground-water storage. Urbanization has not only occurred on areas previously devoted to agriculture, but also on desertlands. These desertlands previously did not have a water requirement and now must depend entirely upon ground water. It is presently estimated that the ground-water overdraft in the Gila River Basin is approximately 2,200,000 acre-feet per year. This overdraft is expected to increase until such time as additional water is made available to meet the present water demands of the area. With the water from the Gila and its tributaries almost entirely committed to meet the demands of the lower elevation valley lands, the mountainous tributary areas have been forced to curtail their growth. The growing urban population centers in the lower valleys are now exerting pressure on these tributary areas to provide home and recreation facilities in the higher elevations. The other principal tributary of the Colorado River within the State is the Little Colorado River. Its basin is traversed by an intercontinental railroad and highway, along which are a number of small, scattered communities that are at present experiencing ground-water overdraft situations similar to other municipalities throughout the State. Agricultural development in the Little Colorado River Basin is limited because of the lack of a dependable water supply. A large portion of this basin is within II-9Epson Perfection 4870 Photo, 400 dpi, 8 bit, 1,097,354 byte