Groundwater

Development around Coeur d'Alene Lake has accelerated over the past 25 years. Commercial and residential development adjacent to the lake plus demands for irrigation, recreation, and hydropower raise concerns about the potential for declining lake levels. A comprehensive lake water budget helps resource managers determine the possible effects of growth on lake levels.

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. Groundwater availability issues in the basin include: 1) widespread water-level declines caused by pumping, 2) reduction in base flow to rivers and associated...