Airport’s Tarmac Problem, San Diego County, California

The Problem: The Palomar Airport was built on a landfill. As the landfill aged, the overlying surface soil became incompetent. This dynamic affected the plumbing of an underground storage tank filled with gasoline, causing a leak. The tank was removed, but gasoline vertically descended into the underground. Another consultant classified the groundwater as beneficial and proceeded slowly with an investigation over many years. The investigated contaminated underground was located under the airport’s paved runway and paved apron areas. As a beneficial-water use risk classified contamination, cleanup would be expensive due to the limited access to the Federal rules governing an airport’s tarmac.

Our Solution: We drilled down to determine the vertical depth of the gasoline impact. The gasoline vertical extent was shallow. The groundwater table was deeper. We then re-verified the previous groundwater classification. The agency’s computer-drafted watershed maps’ boundaries, when transposed from the original hand drawn watershed maps, had a universal drafting error. This error favored this property’s groundwater to be re-classified as non-beneficial.  Finally, we updated the assessment report showing shallow gasoline impact in a non-beneficial water use area and requested case closure.

The Benefit: A timely case closure letter by the oversight agency halted the investigation and waived cleanup. This released the airport property for redevelopment and the property owner from further financial consequences.