The Air Force is implementing a greener, money-saving approach to groundwater cleanup on one parcel at the former McClellan Air Force Base as part of a teaming effort with McClellan Business Park and a prospective tenant. The tenant wanted to build a food storage and distribution center on a 42-acre parcel owned by the Park. Park owners were enthusiastic about the deal, but there was a stumbling block.
The parcel where the center would be built contained eight extraction wells and 29 monitoring points used by the Air Force for the cleanup and monitoring of contamination moving very slowly in the groundwater 100 feet underneath the property. Although the property was deeded to McClellan Business Park, the Air Force remains responsible for groundwater contamination and cleanup at the former base. The Air Force has been successfully cleaning up the base since the 1980s.
None of the equipment or the water sampling activities taking place on the parcel would have any impact on food stored aboveground, but the prospective tenant feared his customers might misunderstand the environmental issues. So McClellan Business Park offered to pick up the tab for the Air Force to demolish some of the existing extraction wells and monitoring points on the property and replace them with three new extraction wells and nine new monitor wells, all relocated adjacent to the McClellan Business Park property.
After doing what he calls a “plausibility study,” using a mathematical procedure to build computer models, Dr. Ken Smarkel, groundwater program consultant at McClellan, determined moving the equipment to meet the tenant’s needs would not hinder the Air Force’s groundwater cleanup efforts. In fact, the Air Force will realize thousands of dollars in savings from having fewer monitoring wells, fewer water samples to be analyzed, and fewer gallons of water for treatment and disposal. These reductions also mean reduced energy requirements for extraction and treatment of the groundwater. The groundwater cleanup program will continue as effectively as before.
Dr. Smarkel identified a few conditions for his endorsement of the change: the new wells must maintain “capture” of the plume (all contaminated water in the plume must be pulled into the well for treatment), the new configuration cannot extend the estimated time frame for “pump and treat” cleanup, and the new wells must not be any more expensive to maintain and operate than the existing system. If any of those conditions are not met, the Air Force would not proceed with these configuration changes.
The work plan for the proposed changes must be approved by federal and state regulators including : the U.S. Environmental Protection Agency, the California Department of Toxic Substances Control, and the Central Valley Regional Water Quality Control Board. The field work is planned to take place in April following approval of the work plan. After the new wells have been installed, the old ones will be properly closed by filling them with concrete and capping them five feet below the surface.
McClellan Air Force Base used many chemicals to support military activities while the base was active from 1936 until it closed in 2001. Fuel, solvents, and cleaners sometimes escaped into the environment from leaking tanks, being washed down floor drains, or spills. Past chemical disposal practices also contributed to soil and groundwater contamination at McClellan, where the water table is 90 to 105 feet below the ground surface.
In 2005, the Air Force groundwater cleanup hit a milestone. In agreement with the regulatory agencies, they announced that all contamination was contained and all treatment systems needed to complete the cleanup are in place.
The Air Force Real Property Agency, working with regulators, oversees the cleanup and transfer of property to the community. Approximately 100 extraction wells pull contaminated water from the ground and transfer it to an above-ground treatment system, where 1,500 gallons of water per minute are treated. The treated water is tested to make sure it meets State regulations and health guidelines before it is discharged to Magpie Creek, which eventually drains into the Sacramento River. About 650 wells have been installed in and around McClellan to monitor contaminant concentrations and plume movement. Each well has an individual testing schedule (ranging from quarterly to once every five years). No water from the former McClellan AFB is used as drinking water. Drinking water at McClellan is provided by municipal water agencies.
For more information about the environmental cleanup, please contact Mary Hall at McClellan Community Relations, 643-0830, extension 232, or by email at mary.hall.5.ctr@us.af.mil.