New Lock at the Soo: Unlocking the Great Lakes


Carrie Fox

, Detroit District

The U.S. Army Corps of Engineers (USACE) Detroit District works on unlocking the Great Lakes by providing a much-needed resiliency at the Soo Locks with the construction of the New Lock at the Soo. The new lock will be the same dimensions as the Poe Lock, at 1,200 feet long, 110 feet wide, and 30 feet deep.

Often called the “linchpin” of the Great Lakes navigation system, the Soo Locks are located in Sault Ste. Marie, Michigan, between the upper peninsula of Michigan and the Canadian province of Ontario. The Soo Locks enable bulk carrier vessels to safely bypass the swift-moving St. Marys River rapids, where the water drops 21 feet over bedrock in a three-quarter-mile stretch. The St. Marys River is the only connecting waterway between Lake Superior and the lower Great Lakes.

Before the first lock was constructed in 1798, trade canoes had to be unloaded and portaged around the rapids, taking roughly six weeks to complete. Today, the locks operate 24 hours a day, seven days a week, 42 weeks of the year, allowing government, commercial, and private vessels to transit safely and more efficiently.

Artistic rendering of what the Soo Locks facility in Sault Ste. Marie, Michigan, will look like when the New Lock at the Soo is complete in 2030.
Artistic rendering of what the Soo Locks facility in Sault Ste. Marie, Michigan, will look like when the New Lock at the Soo is complete in 2030.

“Nearly all domestically produced high-strength steel, 95%, used to manufacture products like automobiles and appliances, is made with iron ore that transits the Soo Locks,” said Mollie Mahoney, New Lock at the Soo senior project manager. “Of the iron ore that transits the Soo Locks, 88% of it is restricted to the Poe lock due to vessel size.”

The Poe Lock opened in 1968 and will be 62 years old when the New Lock at the Soo is scheduled to be complete in 2030.

“The reason the Soo Locks have been so reliable over the years is due to the recurring construction of new locks every two or three decades,” LeighAnn Ryckeghem, Soo Locks operations manager, said. “Up until now, the biggest gap was 24 years from [the] opening of the Sabin Lock to the MacArthur Lock.”

Soo Locks lock and dam operators chip ice off the Poe Lock miter gate in Sault Ste. Marie, Michigan, during the 2022 winter season. The ice needs to be chipped off for the miter gates to fully close.

Currently, all major maintenance on the Soo Locks is completed during the federally regulated annual closure period from Jan. 15 to March 25. The closure period is driven in part by Great Lakes ice conditions, which typically restricts vessel traffic during this period. “The Detroit District team works long hours in extreme cold and snowy conditions to complete a significant amount of maintenance during this time. The work they perform is unique, especially given the harsh northern Michigan conditions they work in,” Ryckeghem said.

According to a 2015 Department of Homeland Security study, “an unanticipated closure of the Poe Lock, the only lock large enough at the Soo Locks to allow passage of the lakers [lake freighters] carrying iron ore, would be catastrophic for the nation. A six-month Poe Lock closure would temporarily reduce the U.S. gross domestic product (GDP) by $1.1 trillion, resulting in the loss of 11 million jobs: approximately 75% of the U.S. integrated steel production would cease within two to six weeks after a closure of the Poe Lock; approximately 80% of iron ore mining operations would shut down; and nearly 100% of North American appliances, automobile, construction equipment, and farm equipment, mining equipment and railcar production would shut down.”


Upon completion of the New Lock at the Soo, the facility will have two 1,200-foot lock chambers and one 800-foot lock chamber. After commissioning of the New Lock at the Soo, the Poe Lock will be out of service for several years for major rehabilitation. Once all three locks are operational, one lock will be able to be taken out of service during more favorable periods of weather without affecting navigation.

The New Lock at the Soo is being built in the footprint of the existing Sabin Lock, the northern-most lock on the Soo Locks facility, opened in 1919. The construction program, which includes improvements to the northern approach channel, is occurring in three phases of work. Phase 1 includes deepening the upstream approach to the northern channel from 24 feet to 30 feet deep so modern vessels can approach the New Lock at the Soo. Phase 2 includes rehabilitating the upstream approach walls to guide vessels into the new lock, and will allow the vessels to moor on the wall. The existing approach walls in the northern channel are the same age as the existing Sabin and Davis locks – more than 100 years old. Phase 3 includes demolishing the existing Sabin Lock, infilling the Davis Lock, constructing a new pump well, and constructing the new lock chamber.

“The Corps of Engineers continues to work hard to maintain the pace and continue to make progress toward New Lock at the Soo total project completion in 2030,” said Mahoney.

New Lock at the Soo Phase 2: Upstream approach walls progress shown between April and September 2022 at the Soo Locks in Sault Ste. Marie, Michigan. The Phase 2 contractor is placing a total of 52 coffer cells and several transition walls to rehabilitate the more than 100-year-old walls for the upstream approach to the new lock.
New Lock at the Soo Phase 2: Upstream approach walls progress shown between April and September 2022 at the Soo Locks in Sault Ste. Marie, Michigan. The Phase 2 contractor is placing a total of 52 coffer cells and several transition walls to rehabilitate the more than 100-year-old walls for the upstream approach to the new lock.

All major phases of the New Lock at the Soo have been awarded. Phase 1 was substantially complete as of Aug. 1, 2022. The $52 million contract was performed by Trade West Construction Co.; they removed about 300,000 cubic yards of bedrock and overburden from the north channel. Trade West used mechanical means to remove the material by using rippers and excavators placed on barges to break up and remove the material. The removed material was placed on the Northwest Pier of the Soo Locks facility and will act as a wind break for transiting vessels.

Phase 2 is currently in the second year of construction and is estimated to be compete in summer 2024. The contractor, Kokosing-Alberici, is placing a series of coffer cells filled with stone aggregate and concrete in front of the 100-plus-year-old Sabin Lock walls. The contract is valued at $117 million, and includes a total of 52 coffer cells, along with several transition walls constructed with steel sheet piles. All the coffer cells and transition walls will be capped with concrete, which will serve as the walking surface of the new walls along the upstream approach channel.

The base contract for Phase 3 was awarded to Kokosing Alberici Traylor, LLC, on July 1, 2022. With timely award of all nine contact options, this phase of work is expected to be complete in 2030. The new lock chamber will be the same size as the Poe Lock to provide resiliency in the operations and maintenance between the New Lock at the Soo and the Poe Lock. There will be some new features on the New Lock at the Soo, such as hands-free mooring units.

“Hands-free mooring units act like suction cups that hold the ship in place moving up as the chamber fills or down as it empties,” Rachel Miller, new lock supervisory civil engineer said. “These units will be a safety upgrade to using line handlers, the current method of mooring ships in the lock chamber.”

The award of the Phase 3 base contract is a major milestone for the project. Awarding the base allows the contractor to begin a substantial portion of the required work. To date, the base contract and one of the nine options have been awarded, with a total value of $1.071 billion. With continued funding, the remaining work, valued at $802 million, is ready to be awarded over the next three years.

A major cost increase led to a five-month contract award delay while USACE developed necessary reports to deliver a new cost estimate for reauthorization to Congress. The cost increase root causes include changing market conditions, inflation, a nationwide labor shortage, design modifications, and early estimate assumptions. Since the project’s last authorization in 2018, the project’s cost increased from $1 billion to $3 billion.

“We recognize funding a larger amount for the New Lock at the Soo is a challenge that could potentially result in schedule impacts,” said Deputy District Engineer Kevin McDaniels. “The Corps of Engineers is partnering with industry and federal agencies to find collaborative solutions aimed at addressing the cost impacts to Corps of Engineers programs and projects nationwide.”

In 2022, the New Lock at the Soo received $478.9 million in the Bipartisan Infrastructure Law (BIL) and $214.2 million in the 2022 BIL addendum (contingent upon the project’s reauthorization at a higher cost in the 2022 Water Resources Development Act). The 2022 BIL addendum funds allow USACE to award some of the remaining $802 million work required to make the New Lock at the Soo fully functional.

The Soo Locks, recognized as nationally critical infrastructure, continue to receive bipartisan support in Congress for funding the new project.
The Soo Locks complete more than 7,000 vessel passages a year, moving up to 75 million tons of cargo. Moving bulk cargos though the Soo Locks and across the Great Lakes saves more than $3.9 billion per year in freight costs, compared to moving the same tonnage by rail or truck. One 1,000-foot vessel can carry the equivalent of seven 100 car trains with a 10,000-ton capacity or 3,000 large trucks with a 25-ton capacity each.

The New Lock at the Soo will be named by Congress, most likely after it is completed.

For more information about the New Lock at the Soo project, visit:

Share this article ...
America's Engineers: The People, Programs, and Projects of the U.S. Army Corps of Engineers ® is published by American Conference & Event Media, LLC.

Reproduction in whole or in part without written permission is prohibited.

American Conference & Event Media, LLC., and the U.S. Army Corps of Engineers (USACE) do not assume and hereby disclaim any liability to any person or company for any loss or damage caused by errors or omissions in the material herein, regardless of whether such errors result from negligence, accident, or any other cause whatsoever. The views and opinions in the articles or advertisement are to be taken as the official expression of the publisher, staff, or writers, unless so stated. Neither the publisher nor USACE warrant, either expressly or by implication, the factual accuracy of the articles or advertisements herein, nor so they so warrant any view or opinions offered by the authors of said articles.

Permission to use various images and text in the publication and on this website was obtained from USACE or U.S. Department of Defense (DOD) and its agencies, and in no was is used to imply an endorsement by USACE nor any DOD entity for any claims or representations therein. None of the advertising contained herein implies USACE or DOD endorsement of any private entity or enterprise. This is not a U.S. government publication or website.
© 2023 American Conference and Event Media, LLC.
linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram