Duluth Harbor
Abnormalities below the Duluth, Minnesota harbor surface have engineers and scientists debating how to slow the rapid corrosion that threatens the long-term structural integrity of the largest Great Lakes port.
The corrosion is occuring at a rate believed to be two to 10 times faster than expected. The corrosion is eating away an estimated 13 miles of steel plates lining the harbor, metal that provides support for bridges, iron ore loading docks and other vital structures.
Theories abound about the cause, including stray electrical currents, road salt runoff, zebra mussels and pollution. Lower levels of harbor pollution and the arrival of zebra mussels may be speeding the corrosion process because there is more dissolved oxygen in the water.
December 3, 2005 3:24 AM | Category: Piers