A hydrologic appraisal of Arizona's ground water as affected by the state code.

Abstract

The availability of ground water has played a significant role in Arizona's growth. Of the approximately 7 million acre-feet of water used annually, almost 5 million acre-feet come from ground water. As a result of a rapidly increasing draft on ground-water supplies, the Arizona legislature passed the Ground Water Code of 1948. This act gave the State Land Department the authority to declare certain regions to be critical ground-water areas. In a critical area, the State Land Department has the authority to prohibit the construction on new irrigation wells. At this time (1968) there are nine critical areas which cover approximately 5 percent of the state. These areas coincide with the regions of greatest agricultural and municipal development. This investigation indicates that since the enactment of the 1948 Code annual ground-water pumpage in critical areas has stabilized. Most noncritical regions show an increasing rate of pumpage. There are economic factors in addition to any legal constraints, which may be responsible for reduction in annual pumpage. In some portions of the state the depth to water is such that it is not profitable to pump ground water for certain low-value crops.