If the old pipelines under the Straits of Makinac burst, more than 700 miles of the Great Lakes shoreline are at at risk for oil spills, a University of Michigan study has revealed.
The computer-modeling study conducted by hydrodynamics expert David Schwab included 840 oil spill simulations from the Enbridge Line 5 pipeline that lies underneath the Mackinac strait.
The simulation, under the support of National Wildlife Federation, found more than 245 kilometers (152 miles) of Huron and Michigan lakes shoreline could be greatly affected by a single oil spill. Once all 840 simulated spills were plotted, the researchers found that about 1,162 kilometers (720 miles) of U.S. and Canadian shorelines would become vulnerable to the spills.
Those with the highest risk include Bois Blanc and Mackinac islands, as well as areas that are directly west and east of Mackinaw City. Beaver Island, Harbor Springs, Cross Village, Cheboygan and other communities along the Huron and Michigan lakes' shoreline would also be greatly affected.
The report is, by far, the only study that detailed the length and speed in case an oil spill occurs. Schwab's study provides a very good material the government can use when planning for a spill-response.
Mike Shriberg, National Widlife Federation's Great Lakes Regional Center regional executive director, believes that the study is an important component of assessing Line 5's risk to the Great Lakes.
"Michigan public officials have an important decision to make about how to protect our communities, economy, wildlife and Great Lakes from an oil spill disaster," Shriberg said.
Using a high-resolution hydrodynamic model developed by Schwab ad Eric Anderson of the National Oceanic and Atmospheric Administration's (NOAA) Great Lakes Environmental Research Laboratory, the researchers were able to do simulations that incorporated approximations in case an oil spill occurs at the halfway point of the 5-mile wide Straits of Mackinac.
The study also showed several significant findings including that in one of the 840 simulations, the open waters of Lake Huron and Lake Michigan would have 60 percent and 15 percent of visible oil, respectively. The open water, at risk, is 44,405 square kilometres (17,318 square miles), almost equal to the combined surface areas of lakes Ontario and Erie.
A single hypothetical spill covers a maximum open water area of 1,600 square kilometres (624 square miles), which is bigger than Lake St. Clair.
The simulation also noted that visible surface oil can arrive at the shore in just 2.5 hours. The whole Mackinac Island could be severely affected in just nine hours and can reach Cheboygan in 30 hours.
The extent of the oil spill is due to the volume of oil that passes through Enbridge Line 5 pipeline under the Straits of Mackenzie. About 20 million gallons of light synthetic crude oil, light crude oil, and natural gas liquids pass through the pipes each day.
In case of a 25,000 barrel spill scenario, Schwab said a cleanup of Mackinac Island is 90 percent probable. It is important to note that the study simulation did not include a containment action to stop the oil spill at the Straits of Mackinac.
The present study complements Schwab's 2014 study, which only used two computer simulations, and aims to help Michigan officials to decide on the old pipeline before an oil spill happens and a beach cleanup becomes necessary.
A previous study by marine scientists from University of Georgia who lab-simulated an oil spill, which released 172 million gallons of oil in the Gulf of Mexico, revealed that chemical dispersants used to remove oil from the water were not able to fully degrade it and even hurt the oil-degrading microbes present in the water.