Water Use and Availability

Our previous study showed declining groundwater levels and streamflow over the past few decades. These decreases may be related to consumptive use or climate changes. To help resource managers plan for growth and development, it’s important they understand current and historical hydrologic processes, land use, and water use.

Wood River Valley residents rely on groundwater for domestic supply, either from domestic or municipal-supply wells. The rapid population growth since the 1970s has caused concern about the long-term sustainability of the groundwater resource.

Sedimentation of Lower Granite Reservoir, operated by the U.S. Army Corps of Engineers, affects commercial navigation and reservoir storage capacity. Some groups are concerned that dredging the reservoir to remove excess sediment may negatively affect endangered species such as steelhead and salmon.

Some groups are concerned that dredging the reservoir and the confluence of the Snake and Clearwater Rivers to remove excess sediment may mobilize contaminants in sediment that could negatively affect endangered species such as steelhead and salmon.

To make scientifically based water-resource decisions, elected officials, water managers, and the general public need additional information about the Wood River Valley aquifer system. A crucial part of this information is an improved understanding of the extent, thickness, and hydraulic properties of the aquifer—a hydrogeologic framework.

A component of groundwater availability is whether the water quality is suitable for a particular use. Elected officials, water managers, and the general public have raised concerns about whether water quality has been affected in developed and agricultural areas by wastewater disposal, fertilizer application, and animal waste.

Groundwater is the primary source of water supply to Ada County’s growing population. Because of a proposed development near Mayfield, the Idaho Department of Water Resources (IDWR) initiated the East Ada County Hydrologic Project to improve the scientific understanding of the groundwater resources in the area. The IDWR asked us to try to answer the following questions: What direction is the...

The State of Idaho needs to determine stream discharge, adjusted to remove fluctuations resulting from the operation of hydropower facilities, in the Snake River below Swan Falls Dam near Murphy, Idaho. The State will use this information to distribute water to owners of water rights in the middle Snake River, particularly at thresholds of 3,900 and 5,600 ft3/s. Water exchange between surface...

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...