Working together, our Thousand Oaks and San Diego offices achieved site closure from the San Diego Regional Water Quality Control Board and kudos from our client. Well-deserved considering this was a highly-complex and challenging site investigation and corrective action project.
For many years, our team operated a high-vacuum dual-phase extraction system (HVDPE) to remove contaminants at the World Oil Chula Vista, California site. During the project, we discovered and determined that the site's petroleum contaminant plume was commingled with a neighboring former gas station's UST release.
After World Oil and the identified contributing responsible party reached an agreement, the site was entered into California's UST Cleanup Fund's Commingled Plume Account (CPA). With that funding and commingled arrangements in place between the parties and involved agencies, we began work on a broader plume-wide investigation and cleanup approach. We replaced wells; assessed the commingled groundwater plume including wells on several neighboring properties and the City right-of-way; ensured public safety with detailed evaluations; and prepared investigation reports, a Conceptual Site Model, and an updated Corrective Action Plan (CAP). With the agency oversight of the commingled plume CAP, we were able to remediate the sites to meet the State's low-threat criteria, facilitate agency negotiations, remove dozens of wells and treatment equipment, restore the sites to acceptable conditions, and achieve no further action letters for the commingled cases within seven years of entering the CPA.