Monday, July 14, 2014

Straits of Mackinac ‘worst possible place’ for a Great Lakes oil spill

University of Michigan News: Because the strong currents in the Straits of Mackinac reverse direction every few days, a rupture of the oil pipeline beneath the channel would quickly contaminate shorelines miles away in both lakes Michigan and Huron, according to a new University of Michigan study commissioned by the National Wildlife Federation.

In one scenario examined in the study and accompanying animations, oil from a hypothetical pipeline break reached Mackinac Island and Round Island after 12 hours and Bois Blanc Island after two days. All three islands are in westernmost Lake Huron, just east of the straits.

Within 20 days of a spill in the Straits of Mackinac -- which separates Michigan's upper and lower peninsulas and connects lakes Michigan and Huron -- oil would spread as far west as Beaver Island in Lake Michigan, a distance of roughly 35 miles, and as far southeast as Rogers City in Lake Huron, a distance of about 50 miles, according to the computer-simulation study released today and conducted by hydrodynamics expert David Schwab of the U-M Water Center.

The area around the 5-mile-wide straits is considered ecologically sensitive and is a major tourist draw. "If you were to pick the worst possible place for an oil spill in the Great Lakes, this would be it," Schwab said. "The currents are powerful and change direction frequently. In the event of an oil spill, these factors would lead to a big mess that would be very difficult to contain."

Just west of the Mackinac Bridge, two 20-inch underwater pipes carry 23 million gallons of crude oil daily through the straits. The 61-year-old pipeline is operated by Enbridge Inc.

..."Any material released into the straits will go into both Lake Michigan and Lake Huron, which would complicate containment efforts," Schwab said. "Hopefully, these simulations and animations will be useful in understanding and preparing for potential impacts."...

Under the Mackinac Bridge crossing the Straits of Mackinac, shot by varnent, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

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