Soo Locks Explained

St. Marys Falls Canal
Nrhp Type:	nhl
Location:	Sault Ste. Marie, Michigan
Coordinates:	46.5033°N -84.35°W
Architect:	Corps of Engineers
Designated Nrhp Type:	November 13, 1966^[1]
Added:	November 13, 1966
Refnum:	66000394
Designated Other1:	Michigan State Historic Site
Designated Other1 Date:	February 12, 1959^[2]

The Soo Locks (sometimes spelled Sault Locks but pronounced "soo") are a set of parallel locks, operated and maintained by the United States Army Corps of Engineers, Detroit District, that enable ships to travel between Lake Superior and the lower Great Lakes. They are located on the St. Marys River between Lake Superior and Lake Huron, between the Upper Peninsula of the U.S. state of Michigan and the Canadian province of Ontario. They bypass the rapids of the river, where the water falls . The locks pass an average of 10,000 ships per year,^[3] despite being closed during the winter from January through March, when ice shuts down shipping on the Great Lakes. The winter closure period is used to inspect and maintain the locks.

The locks share a name (usually shortened and anglicized as Soo) with the two cities named Sault Ste. Marie, in Ontario and in Michigan, located on either side of the St. Marys River. The Sault Ste. Marie International Bridge between the United States and Canada permits vehicular traffic to pass over the locks. A railroad bridge crosses the St. Marys River just upstream of the highway bridge.

The first locks were opened in 1855. Along with the Erie Canal, constructed in 1824 in central New York State, they were among the great infrastructure engineering projects of the antebellum United States. The Soo Locks were designated a National Historic Landmark in 1966.^[4]

United States locks

The U.S. locks form part of a canal formally named the St. Marys Falls Canal. The entire canal, including the locks, is owned and maintained by the United States Army Corps of Engineers, which provides free passage. The first iteration of the U.S. Soo Locks was completed in May 1855; it was operated by the state of Michigan until transferred to the U.S. Army in 1881.

Locks

The configuration consists of two parallel lock chambers.Starting at the Michigan shoreline and moving north toward Ontario, these are:

• The MacArthur Lock, built in 1943. It is long, wide, and deep.^[5] This is large enough to handle ocean-going vessels ("salties") that must also pass through the smaller locks in the Welland Canal. The first vessel through was the SS Carl D. Bradley.
• The Poe Lock, built in 1896. The first vessel to pass through was the U.S. Army Corps of Engineers tug USS Hancock.^[6] The original Poe Lock was engineered by Orlando Poe and, at long and wide, was the largest in the world when completed in 1896.^[7] The lock was re-built in 1968 to accommodate larger ships, after the Saint Lawrence Seaway opened and made passage of such ships possible to the Great Lakes. It is now long, wide, and deep. It can take ships carrying of cargo. The Poe is the only lock that can handle the large lake freighters used on the Upper Lakes. The first passage after the rebuild was by the Phillip R. Clarke in 1969.^[7]

Former locks

• The State Lock, built between 1853 and 1855. The State of Michigan was given land by the federal government to construct a lock after copper and iron ore was discovered on Lake Superior. The lock consisted of two chambers back-to-back to bridge the difference in water level.^[8] This lock was long, wide, and deep.^[8] The State Lock was replaced by the original Poe Lock.
• The Weitzel Lock, was built between 1873 and 1881 directly south of the State Lock, and was the first lock to be operated by the federal government. At long, wide, and deep, it was the longest lock in the world upon its completion. It was decommissioned in 1919, and was eventually replaced by the MacArthur Lock in 1943.^{[8] [9] [10]}
• The Davis Lock, built in 1914. At the time of its completion, the Davis Lock was the longest lock in the world at long, and was also wide and deep.^[8] It was officially decommissioned in 2010.^[11]
• The Sabin Lock, built in 1919.^[8] It was constructed as a twin lock to the Davis Lock, and named after Louis Sabin, who served as the Detroit District Engineer. It was officially decommissioned in 2010 at the same time as the Davis Lock.^[11]

New lock

A new lock is under construction and is slated to be completed by 2030.^[12] Groundbreaking for the new lock project was held on June 30, 2009.^[13] The lock will be equal in size to the Poe Lock and will provide much needed additional capacity for the large lake freighters.^[14] The new lock replaces two locks (Davis Lock and Sabin Lock), which were obsolete and used infrequently. In May 2020, construction on Phase One of the replacement of the Sabin Lock was started.

North of the new lock is an additional channel with a small hydroelectric plant, which provides electricity for the lock complex.

Engineers Day

The U.S. Army Corps of Engineers, Detroit District, operates the Soo Locks Visitors Center and viewing deck for the public.^[15] On the last Friday of every June, the public is allowed to go behind the security fence and cross the lock gates of the U.S. Soo Locks for the annual Engineers Day Open House.^{[16] [17]} During this event, visitors are able to get close enough to touch ships passing through the two regularly operating locks. Other than on that day, because the locks are United States Federal property under command of the U.S. Army Corps of Engineers, unauthorized personnel and civilians are restricted from the locks under threat of fines or imprisonment for trespassing.

Canadian lock

See main article: article and Sault Ste. Marie Canal.

The first lock to be built in the St. Marys River was on the Canadian side in 1798 by the Northwest Fur Company to facilitate the fur trade.^[8] It was destroyed by the Americans in 1814 during the War of 1812 to disrupt British trade.^[8] Currently, a single small lock is operated on the Canadian side of the Soo. Opened in 1895, it was rebuilt in 1987, and is long, wide and deep.^[18] The Canadian lock is used for recreational and tour boats; major shipping traffic uses the U.S. locks.

References

• 33 CFR 207.440
• 33 CFR 207.441

Further reading

• Book: Taylor, Paul . 2009 . Orlando M. Poe: Civil War General and Great Lakes Engineer . . 978-1-60635-040-9.

External links

• Aerial views
• Soo Locks homepage U.S. Army Corps of Engineers Soo Locks page
• Web Camera view of the American locks NOTE: This Connection is Untrusted
• Animation of how the Soo Locks work.
• YouTube video HD video of a ship passing through the MacArthur Lock

Notes and References

1. Web site: St. Marys Falls Canal . June 27, 2008 . National Historic Landmark summary listing . National Park Service . dead . https://web.archive.org/web/20121006235352/http://tps.cr.nps.gov/nhl/detail.cfm?ResourceId=272&ResourceType=Structure . October 6, 2012.
2. Web site: State Historic Preservation Office . Saint Mary's Falls Canal . 2009 . Historic Sites Online . . June 26, 2010 . dead . https://web.archive.org/web/20120511130143/http://www.mcgi.state.mi.us/hso/sites/45419.htm . May 11, 2012 . mdy-all.
3. Web site: . Detroit District . Facts . October 22, 2008 . dead . https://web.archive.org/web/20110110083843/http://www.lre.usace.army.mil/newsandevents/publications/publications/soolocks-saultste-marie/facts/ . January 10, 2011 . mdy-all.
4. Web site: NHL nomination for St. Marys Falls Canal. National Park Service. 2017-04-03. August 28, 2022. https://web.archive.org/web/20220828031116/https://npgallery.nps.gov/NRHP/GetAsset/NHLS/66000394_text. live.
5. Web site: $227 million lock replacement could start this year . David Helwig . SooToday.com . March 30, 2002 . July 12, 2012 . September 20, 2002 . https://web.archive.org/web/20020920190306/http://www.sootoday.com/Content/News/full_story.asp?StoryNumber=293 . live .
6. Book: Arbic, Bernard . Nancy . Steinhaus . Upbound Downbound: The Story of the Soo Locks . 2005 . Priscilla Press . Allegan Forest, MI . 35–37.
7. Web site: Seeing The Light: Orlando Metcalfe Poe . Terrypepper.com . May 30, 2000 . April 10, 2012 . October 14, 2009 . https://web.archive.org/web/20091014232257/http://www.terrypepper.com/Lights/closeups/ompoe/ompoe.htm . live .
8. Web site: Unlocking the Industrial Midwest: A Pictorial History of Locks at the Soo . United States Army Corp of Engineers Detroit District website . USACE . 16 May 2024.
9. Saint Marys Falls Ship Canal (Soo Locks Historic District, Soo Canals), Michigan Department of Labor and Economic Opportunity, 2020.
10. Lange, Alex, "The Mighty Soo: Construction of the Locks at Sault Ste. Marie, Michigan", The Unwritten Record. National Archives, January 5, 2017.
11. News: Henry . Tom . The Soo Locks: The 'linchpin' of Great Lakes shipping is entering a new era . 16 May 2024 . The Blade . Yahoo News . Block Communications . 5 November 2021.
12. Web site: May 2020 . New Lock Info Sheet . live . https://web.archive.org/web/20210515124752/https://www.lre.usace.army.mil/Portals/69/docs/New%20Soo%20Lock/NewLock_InfoSheet_MAY2020.pdf . May 15, 2021 . 9 February 2021 .
13. News: Construction beginning on new Soo shipping lock . June 30, 2009 . . July 13, 2009 . dead . https://web.archive.org/web/20090707210340/http://www.freep.com/article/20090630/NEWS06/90630082/ . July 7, 2009.
14. Web site: David Helwig . March 30, 2002 . $227 million lock replacement could start this year . SooToday.com . July 12, 2012 . September 20, 2002 . https://web.archive.org/web/20020920190306/http://www.sootoday.com/Content/News/full_story.asp?StoryNumber=293 . live .
15. Web site: Chapter 4: The Watery Boundary . United Divide: A Linear Portrait of the USA/Canada Border . The Center for Land Use Interpretation . Winter 2015 . November 14, 2017 . June 20, 2018 . https://web.archive.org/web/20180620075700/http://www.clui.org/section/united-divide-a-linear-portrait-usacanada-border-3 . live .
16. Web site: Detroit District . Soo Locks: Sault Ste- Marie . March 5, 2011 . United States Army Corps of Engineers . dead . https://web.archive.org/web/20110131070629/http://www.lre.usace.army.mil/_kd/go.cfm?destination=Page&Pge_ID=1324 . January 31, 2011 . mdy-all.
17. Web site: Soo Locks Engineer's Day . June 24, 2010 . March 5, 2011 . January 6, 2011 . https://web.archive.org/web/20110106075610/http://www.saultstemarie.com/june-24,-2011-soo-locks-engineers-day-72/ . live .
18. Web site: Parks Canada . Parks Canada . Sault Ste. Marie Canal National Historic Site of Canada, Natural Wonders & Cultural Treasures . Parks Canada . dead . https://web.archive.org/web/20060718140840/http://pc.gc.ca/lhn-nhs/on/ssmarie/natcul/natcul1_E.asp . July 18, 2006 . mdy-all.