FORMER MCCLELLAN AIR FORCE BASE, Calif. -- The Air Force’s environmental restoration efforts at the former Castle Air Force Base, California, took another step toward the finish line recently when regulatory agencies agreed that ecological monitoring is no longer needed.
The Air Force was required to conduct ecological monitoring at five sites where cleanup actions had already been completed. The monitoring was required every five years, for up to 30 years to ensure site contaminants had not impacted wetland habitats. However, once the Air Force demonstrated to federal and state regulatory agencies there were no adverse effects to the designated wetlands, this monitoring requirement was no longer required.
The Environmental Protection Agency, California Department of Toxic Substances Control and Central Valley Regional Water Quality Control Board recently concluded the monitoring could be permanently discontinued.
“The first monitoring event in 2008 concluded no impact,” said Stanley Pehl, Castle’s base environmental coordinator. “But a second event was requested by the agencies as confirmation. Due to California's extended drought, the next wetlands sampling event could not be conducted until 2016.”
The monitoring included the evaluation of fairy shrimp abundance, plant diversity and plant abundance or coverage. Data from potentially impacted vernal pools were statistically compared with data from selected reference or background pools.
The overall conclusion of the ecological monitoring was that there was no evidence of contaminant-related impacts at any of the associated vernal pools.
Closed Sept. 30, 1995, Castle AFB was one of 40 Air Force installations selected for closure under the Base Realignment and Closure, or BRAC, program.
The Air Force has spent $180 million on the Castle environment restoration program and anticipates spending $67 million more to complete the restoration. The Air Force has transferred all 2,777 acres to public ownership, where assets such as runways and other infrastructure can be optimized to strengthen the local economy with jobs and commerce.
"Everyone is extremely pleased with the cleanup progress at Castle," said Pehl. "With the successful conclusion of ecological monitoring we are further down the homestretch toward site closeout."