Summary of the Columbia Plateau Regional Aquifer-System Analysis, Washington, Oregon, and Idaho

This report summarizes the results of the U.S. Geological Survey's Regional Aquifer-System Analysis program study of the Columbia Plateau aquifer system. The report describes the geologic framework, hydraulic characteristics of rock materials that compose the aquifer system, ground-water movement in the aquifer units, estimates of ground-water recharge, estimates of ground-water pumpage, and effects of surface-water irrigation and ground-water pumpage. The construction and use of a numerical ground-water flow model is described. Based on model results, the effects of potential water-development practices are presented. The ground-water quality and geochemistry of the aquifer system is then discussed.