The Eastern Snake River Plain Aquifer covers more than 10,000 square miles, extending from Ashton to King Hill. The water in the aquifer flows to the southwest at up to 10 feet per day, until it enters the Snake River in the Thousand Springs area near Twin Falls.

The aquifer is a source of drinking water for thousands of rural residents and numerous communities, and plays a critical role in the agricultural industry of southern Idaho. Scientists have estimated that the aquifer may contain as much water as Lake Erie.

Activities at the INL during the past 50 years have affected the aquifer in some areas, primarily near major facilities. However, the increased environmental awareness of the 1970s and 1980s brought about a recognition of the importance of the aquifer. As a result, INL changed waste disposal practices so that ground water was affected less or not at all. These changes include elimination of injection wells, monitoring of liquid effluent discharges, and improved wastewater treatment systems.

Much of the work currently being done at the INL relates to correcting errors made in the past. An agreement called the "Federal Facilities Agreement and Consent Order" (usually referred to as the FFA/CO) was made to implement the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, also known as Superfund) at INL.

The Department of Environmental Quality, DOE, and EPA jointly oversee activities under the agreement.

Some cleanup programs have had limited success, but most have produced tangible results. For example, at the Radioactive Waste Management Complex, a treatment system was installed to extract vapors from organic solvents in the rock and soil above the aquifer to prevent further contamination. At Test Area North, a ground water treatment system is operating to improve water quality near that facility. Contaminated waste ponds at Reactor Technologies Complex have been removed from service and covered to prevent contamination migration. Waste water ponds at INTEC were moved so their water would not transport contamination.

Contaminated soil at many areas of the site has been covered or taken to engineered disposal sites. These environmental cleanup programs, coupled with the decrease in the discharge of contaminants to the aquifer, spell good news for southeast Idaho.