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Chevron to deal with old refinery site Beach erosion along Alaska’s Kenai Peninsula threatens system for recovering polluted groundwater; company proposes stone revetment Wesley Loy For Petroleum News
Chevron is preparing to use a lot of muscle to subdue a nagging environmental problem on Alaska’s Kenai Peninsula.
The company is seeking federal and state approval to control beach erosion at the base of a Cook Inlet bluff atop which the Chevron Kenai refinery at Nikiski once stood.
The refinery operated from 1963 to 1991, when Chevron closed it down. The plant later was dismantled and sold.
An unfortunate legacy of the refinery was a hydrocarbon plume that migrated from beneath the plant down toward the adjacent Cook Inlet, a turbulent water body that supports prized salmon fisheries.
The problem became apparent in 1987, when petroleum contamination was discovered on the beach west of the refinery site.
To contain the pollution, a drainage system for collecting free product and groundwater was built at the foot of the bluff in 1994, along with a protective sheet-pile seawall.
The collection system “has been largely successful in preventing hydrocarbons from reaching Cook Inlet,” according to documents Chevron has filed with the U.S. Army Corps of Engineers. What’s more, the volume of recoverable free product at the bluff “has decreased to negligible amounts.”
But over the past decade, serious beach erosion has exposed the bottom of the seawall, threatening the integrity of the groundwater collection system.
Proposed fix Chevron has made a number of efforts over the years to replenish the beach in front of the seawall with cobble, sand and gravel material.
Now the company is proposing a more durable solution.
It wants to tear out the 900-foot seawall and the groundwater collection system, and replace them with a rock revetment.
A number of alternative techniques would be used to either treat or capture polluted groundwater. These include chemical oxidation and groundwater extraction wells installed at the top of the bluff, says a Chevron project summary.
The company is seeking a permit from the Army Corps, plus clearance from state officials, to carry out the work.
Construction is scheduled to run through this year and next.
The revetment will be built across the base of the bluff, and will be higher than the maximum expected run-up of waves. It will feature armor stones up to 4 feet in diameter, sourced from a commercial quarry in Chugiak, Chevron’s project description says.
Barges could begin delivering the rocks to the beach in April, but the shipments will be discontinued during salmon season. Some commercial setnet sites are in the vicinity.
A price tag for the project wasn’t readily apparent in the documents Chevron filed with the Army Corps and other agencies.
The Corps, in a March 12 public notice, said it already has made a preliminary determination that the project would have no effect on the endangered Cook Inlet beluga whale.
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