The San Diego Regional Water Quality Control Board Wednesday announced that soil and groundwater contaminated by petroleum near the Mission Valley Terminal have been cleaned following decades of work.
"Cleaning up and restoring the Mission Valley Aquifer for beneficial use and to protect and expand our local water supplies has long been among our top priorities," said David Gibson, executive officer for the regional board. "Today is a milestone for these efforts. This groundwater basin is a critical resource as San Diego adapts to climate change and hotter, drier conditions."
Releases from the tanks and distribution operations held by Kinder Morgan Energy Partners in Murphy Canyon polluted groundwater in the 1980s, then migrated beneath the parking lot of the former Qualcomm Stadium and the San Diego River, "potentially impacting water quality within a one-mile radius and threatening human health and safety," according to a statement from the board.
The petroleum contaminants were discovered in groundwater monitoring wells in 1992 from the 10.5-acre, above-ground fuel storage and distribution Mission Valley Terminal.
In response to the volume of the petroleum discharges — among the largest ever in California — the San Diego water board issued a cleanup and abatement order in 1992, requiring Kinder Morgan to clean up the mess.
The corrective actions, which began years later in 2005, resulted in removal of almost two million pounds of contamination and included the following:
— Installation and operation of 192 soil vapor extraction wells and 19 groundwater extraction wells to treat polluted soil and groundwater. The treatment system processed 1.26 million gallons of contaminated water per day at the peak of its operation;
— A hydraulic containment barrier at the property boundary to contain the groundwater contamination to the terminal property; and
— A monitoring and reporting program for petroleum cleanup to evaluate whether the cleanup system was capable of meeting the remedial goals by the deadline.
In September 2022, the board determined that the cleanup and abatement of the petroleum had reached conditions protective of groundwater, consistent with the "maximum benefit" to Californians and in compliance with the order. Therefore, it was determined no further actions from Kinder Morgan are necessary.
"Cleaning up the contamination of the Mission Valley Aquifer is a remarkable achievement," said Rob Hutsel, president of the San Diego River Park Foundation. "We applaud all parties that worked for so many years to rid the San Diego River and the community of this pollution."
San Diego plans to use the aquifer for groundwater storage and production as part of its groundwater management program.
