Publication Summary

The Aquifer Vulnerability Project piloted an approach to analyzing stresses on ground water quality in the Nooksack basin, located in Whatcom County, Washington. Ground water data was obtained from the Washington State Department of Health (DOH), the Washington State Department of Ecology, the National Resource Conservation Service, and the U.S. Geological Survey (USGS).

The Aquifer Vulnerability Project piloted an approach to analyzing stresses on ground water quality in the Nooksack basin, located in Whatcom County, Washington. Ground water data was obtained from the Washington State Department of Health (DOH), the Washington State Department of Ecology, the National Resource Conservation Service, and the U.S. Geological Survey (USGS).

Data used for this report include potential ground water contamination sources, ground water quality sampling history, surficial aquifer characteristics, and soil properties. ArcView, a Geographic Information System software program, was used to plot and analyze the data.

The surficial aquifers in the Nooksack basin are especially vulnerable to ground water contamination. The ground water quality sampling history clearly shows past ground water contamination from volatile organic compounds and nitrates. The contamination of the aquifer by pesticides has also been an ongoing concern.

The sampling history in this area of the USGS, DOH, and Ecology are available in a Microsoft Access database for the period of record up to 1997. The facilities that Ecology regulates are plotted on maps, and can be updated through the Ecology Facility/Site database. The soils data help identify areas where recharge occurs most readily, and where soil properties that affect chemical fate and transport (such as organic matter content) are located. And the surficial aquifer characterization (Tooley, Erickson, 1997) provides valuable information about where the aquifer is located, the depth to water, and ground water flow direction.

Spatial analysis was used to compare where potential ground water pollution sources are located over the surficial aquifer and soils allowing ready infiltration. Spatial analysis was also used to query for dairies within a specified radius of an historic nitrate exceedence. A simple overlay query can be used to determine which facilities that Ecology regulates lie within a wellhead protection zone. And having the historical sampling record from USGS, DOH, and Ecology allows a comparison of the story each data set tells about ground water quality in the basin, especially with respect to nitrates.

Recommendations include suggestions for improvements in agency coordination, tracking of potential contamination sources (especially nonpoint), data interpretation guidelines, and development of hydrogeological information for the state. The report also discusses information about the data that the user should be aware of.