Line 5 tunnel idea contemplated more than 70 years ago

Jan. 20, 2021

The Great Lakes Tunnel will virtually eliminate the chance of a pipeline incident in the Straits of Mackinac.

Tunnel remains a good idea today

Some Michiganders are familiar with Enbridge’s recent plan to build a tunnel under the Straits of Mackinac to house a replacement section of the dual Line 5 pipeline in the Great Lakes. However, few people likely know that a Michigan professor weighed the merits of a similar idea more than 70 years ago.

Recently, Enbridge discovered a 1949 story in the archives of a Michigan newspaper referencing a tunnel at the Straits. The article in the Milford Times, a weekly newspaper in Oakland County, quotes the former chair of the geology department at the University of Michigan stating, “a tunnel under the Straits would be a costly affair” and would require digging several hundred feet below the surface.

While the educator also believed that “a bridge across the Straits of Mackinac would be unsound,” he was in the ballpark for the general construction parameters and estimated price tag of a tunnel; Enbridge is investing approximately $500 million to build the 4.5-mile long tunnel under the Straits.

Many might have considered such a tunnel a pipe dream seven decades ago, but today, it is close to becoming the next engineering marvel of the Great Lakes State.

The tunnel will house a replacement section of Line 5 that carries natural gas liquids (NGLs) and light crude, which refineries convert into the propane used across Michigan, as well as several other hundred other products for the greater region.

The Great Lakes Tunnel will, according to Enbridge, eliminate the chance of an anchor strike, making it the best long-term solution to enhancing safeguards in the Straits.

“We are committed to continuing the safe and reliable operation of Line 5, because our communities depend on Line 5,” says Enbridge’s regional operations director Mike Moeller. “In our more than six decades of operation, Line 5 in the Straits has performed safely, without incident. By placing it in a tunnel, we’ll reduce the chance of a spill to nearly zero and enhance our ability to perform inspections visually, offering another layer of protection.”

More than 200 Enbridge employees work and live in Michigan. Moeller shared that the Great Lakes Tunnel Project will put approximately another 100 Michiganders to work for several years as they build the tunnel.

According to Enbridge, there is potential for the Great Lakes Tunnel to accommodate other important services, such as fiber-optic cable to provide high-speed internet and improved communications in the Upper Peninsula.

An Enbridge spokesperson says the company is seeking the necessary permits to construct the tunnel.