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Sault-Sainte-Marie Canal (Soo Locks)

The hard-working Soo Locks, in Sault Ste. Marie, Michigan provide passage annually for more than 4,700 immense lake- and ocean-going vessels. The Soo Locks, Welland Canal and St. Lawrence Seaway provide an unbroken water connection between the Great Lakes and the Atlantic Ocean. However, boats larger than 740 feet long and 78 feet wide will not fit through the Welland Canal and can only travel between the four westernmost Great Lakes (Superior, Michigan, Huron and Erie).

Sault Ste. Marie is the oldest city in Michigan and among the oldest cities in the USA. Soo Locks get their name from Sault (pronounced “soo”) Ste. Marie, the 17th century French explorers’ and missionaries’ name for the falls of the St. Marys River.

These men reported a community of Ojibwe people they called "saulteurs" or "people of the falls" living here, where the waters of Lake Superior pour into Lake Huron. The Ojibwe call the falls “bawating” or “gathering place” where they came for fur and fish. This gathering place soon became a center of trade for Europeans to exchange goods for furs.

The St. Marys River drops 21 feet within three quarters of mile at the location of the locks. Before the construction of the canals and locks this series of rapids formed a barricade between the upper and lower river. Cargoes traveling down from Lake Superior or up from the lower lakes had to be unloaded and carried around the rapids and then reloaded on different boats to be transported. The construction of the canals and locks allowed vessels to pass around the rapids making transportation both faster and cheaper.

The Soo Canal, so called, is a mile and six-tenths long. It really is not a canal at all, but instead a lock proposition with a few thousand feet of channel approaches and jetties at each end. Its locks are more analogous to some of those great tidal harbor basins of Europe, to which access for the loading and discharging of vessels is afforded by locks or gates, than to an interoceanic canal.

Locks in the Great Lakes-St. Lawrence Seaway System are located in the St. Marys River, Welland Canal and St. Lawrence River. In the St. Marys River at Sault Ste. Marie, Michigan and Ontario, four parallel locks on the U.S. side and one on the Canadian side were built.

St. Marys River is the outlet of Lake Superior and leaves the lake at Point Iroquois, flowing in a generally southeasterly direction through several channels to Lake Huron, a distance of from 63 to 75 miles, according to the route traversed. The river drops approximately 22 feet with most of the drop (20 feet) occurring at the St. Marys Falls Canal, where four U.S. navigation locks and one Canadian lock allow for the transit of vessels. The natural control of the outflow from Lake Superior was a rock ledge at the head of the St. Marys River. This natural control has been replaced by the locks, compensating works, and powerhouses. As a result, the outflow from Lake Superior is regulated.

Owing to some impassable rapids on the St. Mary river, which connects Lake Superior with Lake Huron, a lateral canal was opened in 1855, at Sault-Sainte-Marie on the United States side of the river, 13 miles long, with two locks in it to surmount the difference in level of 18 feet due to the falls, each lock being 348 feet long and 69 feet wide. By 1870, the development of the navigation necessitated the enlargement and deepening of the Sault-Sainte-Marie Canal to a width of io9 feet and a depth of 16 feet; and a single lock was built alongside the two existing locks, 515 feet long, 60 feet wide at the entrances, and 80 feet in the lock-chamber, and affording a depth of 16 feet of water on the sill, the change of level being effected in a single lift of 18 feet.

These works, completed in 1881, soon become insufficient for the increasing demands of the navigation; and extension works were in progress, with the canal being given a depth of 20 feet; and a new lock is being constructed on the site of the two original locks, having a length of 8oo feet, a width of loo feet, and a depth of 21 feet of water on the sill. A lateral canal is also being constructed with the same object on the Canadian side of the river, with a width of 153 feet and a minimum depth of 18 feet, together with a lock 600 feet long, 80 feet wide in the chamber, and 60 feet at the entrances, affording 16 feet of water over the sill, and having a lift of 18 feet.

The Sault-Sainte-Marie Canal was constructed through St. Mary's Island, to avoid the rapids of the river St. Mary, by a cut 3,500 feet long, with one lock, which will provide a navigable passage between Lake Huron and Lake Superior on the Canadian side; whereas hitherto vessels have had to pass through the St. Mary's Falls Canal on the United States bank of the river.

Vessels using the facilities at the Soo Locks range from pleasure craft as small as 20 feet in length to ocean carriers 730 feet long, to lake carriers 1,000 feet long and 105 feet wide. The locking process varies depending on the type and size of the vessel, weather conditions, lockage demand, and individual lock characteristics. The general locking process, however, is always the same.

Both locks operate in both directions and can either raise or lower boats. The size of the boat determines which lock it will use. Boats larger than 730 feet long and 76 feet wide are too big for the MacArthur Lock and must use the Poe Lock.

The Soo Locks Modernization Act S.1308 — 115th Congress (2017-2018) directs the U.S. Army Corps of Engineers to carry out the project authorized by the Water Resources Development Act of 1986 for the construction of a second lock adjacent to the existing lock at Sault Sainte Marie, Michigan, at a total project cost that is equal to the 2017 certified cost estimate, plus or minus such amounts as may be required by ordinary fluctuations in construction costs.

The navigation season at the Soo Locks ends on January 15th and resumes on March 25th. During this time, work crews undertake “winter work” doing major repairs, inspections and maintenance projects that cannot be done while the locks are in operation.

The Soo Locks are a critical link in the Great Lakes and the St. Lawrence Seaway system. Each year, an average of 7,900 vessels carry 80,000,000 tons of iron ore, coal, stone, grain, and other materials through the Soo Locks. The Corps of Engineers reports that an unscheduled outage at the Soo Locks would cripple both navigational and industrial production in the Great Lakes region.

A report by the Department of Homeland Security concluded that a 6-month shutdown of the Soo Locks would result in : 75 percent of all integrated steel production in the United States ceasing within 2 to 6 weeks; in North America, the shutdown of 100 percent of production of appliances, automobiles, construction equipment, farm equipment, mining equipment, and railcars; and the unemployment of almost 11,000,000 people.

The new lock will have the exact same dimensions as the Poe Lock (1200 feet long X 110 feet wide X 32 feet deep). If a bigger lock were constructed, it is likely that bigger boats would quickly follow – recreating the current situation. It will take 7-10 years, based on uninterrupted construction. However, that could change as work progresses. Previous locks have been delayed by weather, labor disputes and the condition of the bedrock on the site.

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Page last modified: 01-11-2017 19:24:10 ZULU