The Port of Astoria and oil companies have reached a conceptual agreement on how to clean up and prevent petroleum contamination from reaching the Columbia River between the Port’s piers 1 and 2.
Anna Coates, a natural resource specialist with the state Department of Environmental Quality, outlined the history of the issue to the Port Commission on Tuesday and explained the agreement to cap and filter pollution out of the groundwater. There is no cost estimate yet.
“The most important of those is the permeable reactive barrier,” she said. “This is the feature that keeps the contamination out of the surface water, so that’s the most important one. And then the other details can be worked out during the remedial design phase.”
The area of contamination would be excavated and filled with a sloped layer of clay, silt, sand and absorbent material topped with a protective layer of pavement and riprap. A monitoring well would be dug to keep track of how the system works.
Coates will likely write a final record of decision in September or October, with a work plan created around the end of the year.
In the late 1990s, an oil sheen appeared on the Columbia between piers 1 and 2. The state initiated a remedial investigation in 2001 and has since overseen cleanup of the contamination. The main sources were identified as a former ExxonMobil/Niemi Oil bulk plant, a McCall Oil & Chemical Corp. pipeline, an underground storage tank previously operated by the Port and other nearby pipelines.
The major area of concern is a former McCall pipeline leaching petroleum into the Columbia between piers 1 and 2. Several solutions have been proposed over the years to remove the groundwater contamination, from a new bulkhead or a clay cap to leaching out contaminants through wells or solidifying them as rocks.
Hart Crowser, a consultant hired by the Department of Environmental Quality, recently recommended a series of marine mattresses be laid along the slip and covered with rock riprap at a cost of $3.2 million. Neither the Port nor the oil companies warmed to the solution.
The Port had previously recommended a wall be built across the slip to keep contamination out of the river. But Hart Crowser determined the solution was overly expensive and would not last through a large earthquake. Port commissioners shared their concerns that anything less than a wall would not hold up to the area’s rough weather, potentially leaving the agency holding the bag if more contamination reaches the water.
Nobody would be off the hook if the new system fails, Coates said, and the slope would be designed specifically to withstand the area’s weather. Another reason for the slope is creating potential aquatic habitat, something the wall would not allow, Coates said.
“That is something we need to consider for permitting by” the National Marine Fisheries Service, she said.
Thane Tienson, the Port’s attorney during much of the cleanup negotiations, said any solution also needs to take into account climate change.
“You better be thinking proactively about what sea level rise is going to do to coastal communities like my hometown of Astoria, Oregon, over the next 30 years before you commit yourself to something,” Tienson said.