Controlling Pollution at Edwards Air Force Base, California

Superfund sites are designated locations in the USA where a long-term strategy is required to address contamination with hazardous materials. One example is the Edwards Air Force Base whose primary mission is aircraft research and development and which covers over 300,000 acres in Kern, Los Angeles, and San Bernardino Counties, California. The US Environmental Protection Agency (EPA) reports that “spills and poor disposal practices have resulted in the release of volatile organic compounds, metals and other chemicals to the surface, subsurface, and groundwater” (http://cumulis.epa.gov/supercpad/cursites/csitinfo.cfm?id=0902725). This is a large and complex site with multiple sub-areas exhibiting their own particular characteristics, both in terms of activity (including, for example, rocket testing) and the nature of the associated pollution. The contaminants generally lie in fractured bedrock which is difficult geologic material to investigate and remediate.

Herb Levine is a hydrogeologist at EPA Region 9 who provides technical support to EPA project managers, as well as serving on a variety of policy groups within EPA. He has had considerable involvement in the issues which have arisen at Edwards Air Force Base. The key decision-making group involves over 20 people, representing the US Air Force, contractors, and regulators from multiple agencies within the State of California as well as the EPA. In 2017 there was considerable controversy on whether a groundwater contamination plume at one of the sites was stable and in particular whether the decision to shut down a hydraulic cut-off involving 11 extraction wells had been correct. Different software tools had been used in attempts to provide supporting analysis but with inconclusive results. Herb Levine used GWSDAT and its space-time animations convincingly demonstrated the narrowing of the concentration boundaries while the extraction system was operational. The animations also depicted the plume migrating and increasing in concentration when the extraction system was shut off.  This resolved the controversy by convincing all the stakeholders of the presence and nature of the problem and it enabled the discussion to move on to a re-evaluation of site conditions along with progress towards a final remedy. This will be a long term response but the critically important consequence of the analysis is that this process can now begin. Other groundwater contaminated sites at Edwards Air Force Base will utilize GWSDAT along with other software tools to evaluate trends and plume stability.

Reflecting on his involvement at Edwards Air Force Base, Herb commented:
“GWSDAT in my opinion is an invaluable tool for analyzing data over space and time, at Superfund sites and elsewhere. It played a critical role at Edwards Air Force Base and I now recommend the software for use by project managers and their contractors across all the EPA regions in the USA. Its ability to provide real insight quickly and objectively is a huge asset.” Superfund sites in general require expensive investigations and remedies, often requiring millions to tens of millions of dollars. Analytical tools such as GWSDAT are critical for data analysis for insight and potential cost savings.