Introduced centuries ago, tunnel systems are important

The Eisenhower-Edwin C. Johnson Memorial Tunnel, or Eisenhower Tunnel, is the longest mountain tunnel in the United States.

Newest project: Great Lakes Tunnel

Jan. 4, 2023

Editor’s note: For 2023, the Newsroom will explore the importance of tunnels in North America and around the world. Tunnels are an example of creative and engineering genius, and more importantly, they provide practical solutions and help move people and goods from one point to another.

Some are underground, including one connecting the White House and the U.S. Treasury.

Others have been constructed to be in the water, while others were created boring through mountainsides.

Hundreds of thousands of people rely on them every day across the United States.

Introduced in the sixth century, tunnels have become essential to modern-day transportation—for trains, cars and trucks.

Constructed in 1827, the Union Canal Tunnel in Pennsylvania was the oldest transportation tunnel in the U.S. Designed as a towpath—a trail or road along the bank of a waterway. The Union Canal Tunnel extended 82 miles, connecting Philadelphia with the Susquehanna River.

Carrying I-70 under the Continental Divide in the Rocky Mountains, the Eisenhower-Edwin C. Johnson Memorial Tunnel (the Eisenhower Tunnel) is the longest mountain tunnel and highest point on the country’s interstate highway system.

Bored through a mountainside in 1924, the dual Liberty Tunnel in Pittsburgh has the distinction of being the first designed specifically to accommodate automobile travel. Upon its 1924 opening, officials heralded it as an “engineering marvel.”

Closer to home, completed in 1930, the Detroit-Windsor tunnel is an international highway tunnel connecting the cities of Detroit, MI and Windsor, ON. It is the second-busiest crossing between the U.S. and Canada.

Great Lakes Tunnel will serve Michigan and the region

“Tunnels serve as a lynchpin to our transportation system,” said Mike Moeller, Enbridge’s director of the Great Lakes Region.

“They have proven to be efficient alleviating traffic, as well as maximizing the protection and use of our land and waterways.”

Moeller cites that Michigan’s expansive tunnel systems often are considered “the city beneath the city,” comprising what many Michiganders view as one of the state's “man-made marvels.”

“Michiganders are very familiar with the value of tunnels,” Moeller said. “That’s one of the reasons why more than 70 percent of them support Enbridge constructing the Great Lakes Tunnel.”

Placed below the lakebed, the Great Lakes Tunnel will house a replacement section of Line 5 in the Straits of Mackinac. It will eliminate the chance of an anchor strike to Line 5 and essentially eliminate the chance of a spill from Line 5 into the Straits.

“The engineers, safety experts, designers, and hydrogeologists working on the Great Lakes Tunnel not only are experienced, but they also have access to technologies that certainly weren’t available decades ago,” said Moeller.

“This region will be able to continue to rely on the safe operation of Line 5 as the team’s experience combines with technology to deliver the next engineering marvel for Michigan.”