The Columbia Plateau Regional Aquifer System (CPRAS) covers about 44,000 square miles of eastern Oregon and Washington and western Idaho. The primary aquifers are basalts of the Columbia River Basalt Group and overlying basin-fill sediments. Ground-water availability issues in the basin include: 1) widespread water-level declines caused by pumping, 2) reduction in base flow to rivers and associated effects on temperature and water quality, and 3) effects of global climate change on recharge, base flow, and groundwater availability.
The USGS is conducting a study of the Columbia Plateau Regional Aquifer System with the broad goals of: 1) characterizing the hydrologic status of the system, 2) identifying trends in groundwater storage and use, and 3) quantifying groundwater availability.
