Earlier this year, Enbridge applied for a permit to add 48 new anchor supports to its twin oil pipelines that run under the Straits of Mackinac.
The screw-in supports secure the pipelines to the lakebed in places where strong currents have eroded the bottom. No spans of Line 5 longer than 75 feet can be left unsupported, according to Enbridge's easement with the State of Michigan.
The company has been installing these supports since 2002, and based on the information available to Michigan Radio, there are currently 147 in place and 3 approved with plans to install as soon as possible. The company has installed 19 so far this year. We created an animation showing the supports adding up over time.
Some have argued that all of these anchor supports make the pipeline an entirely different structure than its original design, and oppose the maintenance permits the Michigan Department of Environmental Quality has been giving the company to do this work.
Up to 23 million gallons of crude oil flow through the lines each day, traveling from Superior, Wisconsin to Sarnia, Ontario. The oil originates in Western Canada.
Michigan Radio received the following e-mail statement from Enbridge:
"Enbridge’s ongoing work to inspect, maintain and modernize its transport system ensures that Line 5 remains in top condition – keeping the environment safe and securing energy delivery to Michigan and the Great Lakes region.
Anchor supports to Line 5 are a key part of our maintenance program. The supports fortify the lines and further increase overall safety.Ongoing inspections of the system will continue to guide the need for any additional anchors.
Also, as part of our agreement with the State of Michigan we have identified feasible options for the replacement of Line 5 in the Straits. Replacement would help ensure the continued safety and protection of the Great Lakes for future generations. The options we are studying with the State include placing a pipe in a concrete-lined tunnel beneath the Straits."
In full disclosure, Enbridge is one of Michigan Radio's many corporate donors.