Groundwater Quality in the Columbia Plateau and Snake River Plain Basin-Fill and Basaltic-Rock Aquifers and the Hawaiian Volcanic-Rock Aquifers, Washington, Idaho, and Hawaii, 1993–2005

Overview

The Columbia Plateau, Snake River Plain, and Hawaii are large volcanic areas in the western United States and mid-Pacific ocean that contain extensive regional aquifers of a hard, gray, volcanic rock called basalt. Residents of the Columbia Plateau, the Snake River Plain, and the island of Oahu depend on groundwater as their primary source of drinking water. Although the depth to the water table can be several hundred feet, the groundwater is highly vulnerable to contamination because the permeable sediments and rocks allow contaminants to move readily down to the water table. Intense agricultural and urban activities occur above the drinking-water supply and are increasing in some areas. Contaminants, such as nitrate, pesticides, and volatile organic compounds, associated with agricultural and urban activities, have adversely affected groundwater quality.

Major Findings

The Columbia Plateau, Snake River Plain, and Oahu aquifers are vulnerable to contaminants related to human activities despite depths to groundwater that are among the greatest in the Nation Chemicals that have been banned for over 30 years are still a potential human-health concern in groundwater Although the aquifers of the Columbia Plateau, Snake River Plain, and Oahu are composed of similar geologic materials (basalt), contamination issues vary among the aquifers because of differing geochemical conditions and differing land and chemical uses

Summary Report for the National Water-Quality Assessment Program Principal Aquifers Series, "The Quality of Our Nation's Waters—"

Circular 1360—Water Quality in Principal Aquifers of the United States, 1991–2010

Companion Reports

Circular 1337—Water Quality in the High Plains Aquifer, Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming, 1999–2004

Circular 1352—Water Quality in the Glacial Aquifer System, Northern United States, 1993–2009

Circular 1353—Water Quality in the Northern Atlantic Coastal Plain Surficial Aquifer System, Delaware, Maryland, New Jersey, New York, North Carolina, and Virginia, 1988–2009

Circular 1354—Water Quality in the Principal Aquifers of the Piedmont, Blue Ridge, and Valley and Ridge Regions, Eastern United States, 1993–2009

Circular 1355—Water Quality in the Upper Floridan Aquifer and Overlying Surficial Aquifers, Southeastern United States, 1993–2010

Circular 1356—Water Quality in the Mississippi Embayment–Texas Coastal Uplands Aquifer System and Mississippi River Valley Alluvial Aquifer, South-Central United States, 1994–2008

Circular 1357—Water Quality in the Denver Basin Aquifer System, Colorado, 2003–05

Circular 1358—Water Quality in Basin-Fill Aquifers of the Southwestern United States: Arizona, California, Colorado, Nevada, New Mexico, and Utah, 1993–2009

Circular 1359—Groundwater Quality in the Columbia Plateau and Snake River Plain Basin-Fill and Basaltic-Rock Aquifers and the Hawaiian Volcanic-Rock Aquifers, Washington, Idaho, and Hawaii, 1993–2005

First posted January 21, 2015