Oregon State University
Oregon State University

Human Impacts on Groundwater In Oregon

The US Geological Survey (USGS), Oregon Water Resources Department (WRD), Oregon Department of Environmental Quality (DEQ), and others have gathered data about Oregon's groundwater for many years.

Long-term measurements of the water level in wells are used to determine if withdrawals are exceeding recharge. If they are, restrictions are put on groundwater use. See the discussion of the Groundwater Act of 1955 for more details about restricted areas.

Willamette Valley Groundwater Quality

In the 1990s, the USGS sampled private wells in the Willamette Valley for water quality. They found some wells contaminated with nitrate above the limit allowed for public drinking water (>10 ppm). Pesticides and other human-related contaminants were found in a few wells.

Most of the wells showing contamination were in the upper Willamette Valley north of Eugene. Nitrate contamination of groundwater in the region was confirmed by Oregon DEQ during 2000-2002 studies. In 2004, DEQ declared a portion of the Southern Willamette Valley to be a Groundwater Management Area due to elevated nitrate concentrations in drinking water.

For more information on groundwater quality in the Willamette Valley, contact the Eugene office of DEQ or examine the results of the USGS studies listed below.

Water Quality in The Willamette Basin, Oregon, 1991-1995, USGS Circular 1161.

Quality of Shallow Ground Water in Alluvial Aquifers of the Willamette Basin, Oregon, 1993-1995. USGS Water-Resources Investigations Report 97-4082-B.

Groundwater Quantity Studies

Portland Basin Ground-Water Study

Willamette Basin Ground-Water Study

Ground-Water Resources in the Deschutes Basin Groundwater

Upper Klamath Basin Groundwater Study

To order materials or ask for more information about your area contact:

USGS Oregon District office
10615 SE Cherry Blossom Drive
Portland, OR 97216
Phone: 503-251-3200

Oregon District web site: http://or.water.usgs.gov/index.html.