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The Great Lakes Tunnel Project: Separating fact from fiction

Cross section of an underground tunnel

‘Tunnels are inherently stable structures that can remain in service for many decades’

May 22, 2024

“Just the facts, ma’am.”

It was the famous line used by Joe Friday in the TV show Dragnet.

In the 1987 movie of the same name, actor Dan Aykroyd adapted the phrase: “All we want are the facts, ma’am.”

But along with facts, sometimes comes rumors and fiction.

Since the recent announcement about the selection of two premier tunneling companies to lead construction of the Great Lakes Tunnel in the Straits of Mackinac to house Enbridge’s Line 5 pipeline, along with facts about the project some inaccuracies have come to light.

“Let’s set the record straight. Properly designed and constructed, tunnels are inherently stable structures that can remain in service for many decades,” said Tom Schwartz, Senior Vice President Liquids Pipelines, Enbridge Strategic Projects and Partnerships.

“While most people across the region recognize the enhanced environmental and safety benefits the Great Lakes Tunnel will deliver, others continue to perpetuate a litany of misinformation about the Project,” said Schwartz.

“We thought it important to share again the factual information about the Great Lakes Tunnel and why Enbridge is committed to constructing it.”

Fiction

Fact

No one can build a tunnel under the Straits of Mackinac.

Tunneling beneath open water is the most complicated, dangerous and technically challenging construction on Earth. There is no other project on the planet where they have done something like this.

Tunneling underneath water is not new. Every day, people use tunnels that travel under water and through mountains. Today’s technology, excavation techniques, monitoring methods, and preventative measures, have advanced safe construction and stability of tunnels.

The Eurasia Tunnel in Istanbul, Turkey, is a road tunnel that connects Europe and Asia by crossing under the Bosphorus Strait.

Under construction, the Great Istanbul Tunnel is a multi-use underwater tunnel that will also connect Europe and Asia, and is scheduled to open in 2028.

In the U.S., the Chesapeake Bay Bridge-Tunnel (CBBT) is a 17.6-mile bridge and tunnel complex that spans the lower Chesapeake Bay and connects Virginia’s Eastern Shore with the mainland in Virginia Beach, VA. Under construction is a new extension: the Parallel Thimble Shoal Tunnel project involves the construction of a two-lane bored tunnel from the CBBT’s southernmost island (#1 Island) under Thimble Shoal Channel to #2 Island.

Tunneling is dangerous. The industry has not changed much over the years.

Tunneling is one of the most sophisticated industries in the world. Tunnels have been used in Seattle to help take away storm water, move traffic through a park in Houston, to easing congestion under the Port of Miami.

Tunnel boring machines, known as TBMs, are highly sophisticated machines that cut thorough rock while also taking away debris and building the sides of the tunnel as it goes along. TBM’s are a safe and proven technology around the globe.

To learn more, visit the International Tunnelling and Underground Space Association and the Tunnelling Journal.

Enbridge has no experience in constructing a tunnel beneath water. Out of 90,000 miles pipelines, Enbridge has less than one mile of pipelines in tunnels.

After a 21-month process, Enbridge selected Barnard Construction Company, Inc. and Civil Building North America Inc. (CBNA) for their extensive experience building tunnels.

Forming a partnership as the Mackinac Straits Partners, the companies have built more than 100 tunnels in 15 different countries. Those tunnels include the Port of Miami Tunnel in Miami and the Central Subway Tunnel in San Francisco, just to mention a couple of completed projects.

Enbridge has conducted insufficient geologic studies. This will lead to geologic hazards during and after construction phases.

Enbridge has conducted multiple geological studies, invested $40 million in engineering and geo-technical programs, actively accepting guidance from qualified teams of geologists, and implementing geotechnical programs to ensure safety throughout the tunneling project process.

This includes deploying a marine vessel that drills for rock samples, which determines if the ultimate design and structure is suitable for the geology within the Straits.

The tunnel will hurt the environment. Oil could spill out of the tunnel.

The Great Lakes Tunnel is being built to make a safe pipeline even safer and provide secondary containment for a new replacement segment of Line 5 Replacement. In the MPSC permitting process, experts testified the likelihood of a release in the tunnel is less than one in 663,000 years.

Even in the unlikely event that a released occurred, the oil would be contained in the tunnel and oil would never reach the Great Lakes. Like other tunnels, which are static, there will be no emissions. The tunnel will be monitored 24/7, seven days a week.