City of Santa Rosa Garage 9 UST Investigation & Remediation
Santa Rosa, CA

EBA was contracted by the City of Santa Rosa to perform an in-situ remediation of the petroleum hydrocarbon impacts associated with leaking underground storage tanks formerly located within the Garage 9 parking structure.

EBA oversaw the installation of three dual phase extraction (DPE) wells followed by the performance of a 5-day DPE pilot test. Based on the successful removal of contaminant mass during the pilot test, EBA prepared a Remedial Action Plan (RAP) proposing an additional 30-day DPE event which was approved by the North Coast Regional Water Quality Control Board (NCRWQCB) and subsequently performed by EBA.

Additionally, EBA oversaw the installation of monitoring well MW-7 to define the lateral extent of the contaminant plume. Following the 30-day DPE event EBA performed routine post-remedial groundwater monitoring as well as performance of a soil vapor survey to evaluate the soil vapor to indoor air pathway.

Post-remedial monitoring results have shown a significant decline in contaminant concentrations and indicate that the site is eligible for case closure pursuant to the requirements of the Low Threat Underground Storage Tank Case Closure Policy (LTCP).  EBA is currently preparing an LTCP Evaluation Report which will include a formal recommendation and argument for case closure with no further action.