700 Miles of Great Lakes Coast Vulnerable in Oil Spill: Study

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More than 700 miles of shoreline on Lakes Huron and Michigan — roughly the distance from Detroit to Atlanta — could be polluted if aging pipelines under the Straits of Mackinac burst, a new computer modeling study from the University of Michigan warns.

U-M hydrodynamics expert David Schwab, who previously has warned of environmental catastrophe if Canadian oil transport giant Enbridge’s 62-year-old twin pipelines running under the straits were to burst, ran 840 simulations for the National Wildlife Federation-supported study released Thursday.

When all 840 simulated spills were plotted on a map, 720 miles of U.S. and Canadian shoreline are potentially vulnerable to spills that would require cleanup, according to the study.

The areas at highest risk would include some of Michigan’s top tourist destinations and most ecologically sensitive areas, including Mackinac and Bois Blanc islands, locations directly east and west of Mackinaw City, and the communities of Beaver Island, Cross Village, Harbor Springs, Cheboygan and others along the shorelines of the two Great Lakes in northern Michigan.

A total of 720 miles (1,162 km) of shoreline are considered potentially vulnerable to Straits of Mackinac oil spills. This map shows the probability that beached oil concentrations would exceed the threshold needed to trigger shoreline cleanup following the release of 25,000 barrels at the Straits of Mackinac. (Image credit: David Schwab, U-M Water Center)

The study is a detailed follow-up to a 2014 pilot project by Schwab, which used computer simulations to determine how far and how fast an oil spill could spread from the Straits of Mackinac. The new, expanded study is the most comprehensive report on the topic available to the general public.

"Until now, no one knew exactly how much shoreline was vulnerable to spills in the Straits of Mackinac," Schwab, a research scientist at the U-M Water Center, said in a news release. "These findings show that under the right conditions, a spill in the Straits of Mackinac could affect a significant amount of shoreline and open-water areas in either Lake Michigan or Lake Huron, or both, very quickly.”

A task force created by Michigan Gov. Rick Snyder is studying the safety of the pipelines, known collectively as Line 5, and alternatives if it were to be shut down completely, as several environmental groups have advocated.

Enbridge agree last year not to use Line 5 to transport heavy crude oil, but the 63-year-old pipeline still moves up to 20 million gallons of light crude oil, light synthetic crude oil and natural gas liquids, including across the straits each day.

At the time, Enbridge officials said Line 5 is safe and that the company has a response plan if an oil spill were to occur.

Related

• Enbridge on Notice to Reinforce Pipelines to Avoid Great Lakes Catastrophe
• Coast Guard’s Alarming Warning on Great Lakes Oil Spill
• ‘Pinhole-Sized’ Pipeline Lake Heightens Great Lakes Fears
• Activists: Plug Straits of Mackinac Pipeline Before Catastrophe
• Task Force: Straits of Mackinac Pipeline Wouldn’t Be Allowed Today

In a statement, U.S. Sen. Gary Peters, D-Bloomfield Township, said the study illustrates the need for a "swift and complete analysis into Line 5 alternatives in order to protect our lakes and our people."

The Great Lakes are an important asset for tourism, recreation, shipping, economic growth and clean drinking water, he said, and the immense challenges of cleaning up fresh-water oil spills are already known. Peters is a member of the Senate's Commerce Committee and the Great Lakes Task Force.

Mike Shriberg, regional executive director of the National Wildlife Federation’s Great Lakes Regional Center, said in the news release that public officials in Michigan have critical decisions to make about the best way to protect communities, the economy, wildlife and the Great Lakes from an oil spill disaster.

"This report underscores how critical it is to act in the best interest of the millions of people who depend on the Great Lakes for their jobs, water and way of life,” said Shriberg, who also serves on the Michigan Pipeline Safety Advisory Board.

Other key findings of the study:

• Nearly 60 percent of Lake Huron's open water and more than 15 percent of Lake Michigan's open water showed visible oil in at least one of the 840 spill simulations. The total area of those vulnerable open waters — 17,318 square miles — is roughly equivalent to the combined surface areas of lakes Erie and Ontario.
• The maximum open-water area covered by a single hypothetical spill is 624 square miles, an area larger than Lake St. Clair.
• The shortest arrival times for visible surface oil — 2.5 hours — occur on the south shore of the straits, near Mackinaw City. Mackinac Island could be impacted in nine hours, Bois Blanc Island in 10 hours. Oil could reach Cheboygan in 30 hours.

The report, titled "Statistical Analysis of Straits of Mackinac Line 5 Worst-Case Spill Scenarios,” was released Thursday by the U-M Water Center, part of the Graham Sustainability Institute.

Read it below.

(Image credit: Mackinac Bridge via Flickr / Creative Commons)