Summary of the Southwest Alluvial Basins, Regional Aquifer-System Analysis, south-central Arizona and parts of adjacent states

The 72 basins of the 82,000-square-mile study area were grouped into five broad categories on the basis of their geohydrologic characteristics. Water-resources development has resulted in depletion of surface flow in several basins and overdraft of ground water in most developed basins. In places, water levels have declined more than 400 feet; declines of 50 to 200 feet are common in developed basins. Ground-water flow and geochemical models were developed for representative basins.