ANCHORAGE, Alaska (AP) — An engineering professor has figured out why oil remains trapped along miles of gravel beaches more than 20 years after the Exxon Valdez tanker disaster in Prince William Sound.
An estimated 20,000 gallons of crude remain in Prince William Sound. The oil remaining after the nearly 11-million-gallon spill had been expected to biodegrade and wash away within a few years.
The problem: The gravelly beaches are trapping the oil between two layers of rocks. Water — which would break up and dissipate the oil — moves much more slowly through the lower layer.
The study is by Michel C. Boufadel, chairman of the Department of Civil and Environmental Engineering at Temple University. It appeared Sunday in Nature Geoscience’s online publication.