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Description: There was a time, over a century ago, where the St. Mary’s River rapids were unrestricted with very large rapids, and aggressive waterfall which flowed into habitable land. The International Joint Commission decided there was a need to regulate the outflow of Lake Superior and so to tame the rapids, the people on both sides of the river (Canada and USA) came up with a plan and in 1914, construction of Compensating Works dam began...
Completed in 1921, the Compensating Works is a dam that controls the flow of water from Lake Superior into the St. Marys River and is settled in between the two Saults, Sault Ste. Marie, Ontario, Canada and Sault Sainte Marie, Michigan, USA. It consists of eight southern gates belonging to the U.S. and eight northern gates belonging to Canada, with all Canadian gates still being controlled by manually cranking the gates in unison, by hand.
Submitted By: Kelsey MacPherson
City: Sault Ste. Marie
Region: Ontario
Gate one on the Canadian side of the Compensating Works dam has an interesting backstory as well. Previously, with the water control of gate one, came chaos for the variety of fish that caused the rapids home. The water would run low enough to trap them in pools and create an unsafe environment to the species. Now, with the help of the Ministry of Northern Development, Mines, Natural Resources and Forestry, it has been modified to provide a thriving space for these fish. Gate one has become a tourist attraction, as well as a natural fish habitat as it now ensures that these schools of varying fish are supported with the flow of water. The fish are unaffected with these modifications and as such, their sheer size and health reflects the benefits.
Of course, on the flip side, the size and health of the fish have also increased the tourism within the area. Fishing enthusiasts from all over North America (and abroad) come to fish in the St Mary’s rapids, and it has been coined the “premier place to go” for fly fishing. This growing interest in the rapids has provided further interest with local anglers and guides within the area as well, making Sault Ste. Marie one of the most attractive northern areas to explore for fishing.
The development of the dam brings hydro-electric power to the area. This power, provided by the rapids and dam, is then distributed not only to both of the cities of Sault Ste. Marie but to the large mining, smelting, steel, pulp and paper and transportation industries within them.
This dam allows for deep water ports to be built to Algoma Steel, and within other industries. This increases the distribution channels for these industries, which solidifies business in Sault Ste. Marie as well as employment. These ports create employment and security for a lot of trades people within the city. It allows others to invest in the city and its resources and makes exporting a valid option.
Without the Compensating Works dam, both cities of Sault Ste. Marie, would quite literally not exist. Its ability to aid in industry and employment growth, tourism, and nature nurturing are what makes this dam, the most interesting and supportive dam in Canada.
The Compensating Works consists of 16 steel sluice gates founded on bedrock. The structure is completed with a 60 m long earth dike on the south (American) and a 100 m long low earth embankment on the north (Canadian) sides. Every fourth pier is 2.74x19.3m while the intermediate piers are 2.44x17.3m. The structure is approx. 6.7m high with a 3.7 m head at high water level. Each gate is 4m high x 16.1m long.
The first four gates were constructed on the Canadian side and consist of 3 main horizontal plate girders 1.5m wide x 9.8m long in the central portion reducing to 0.8m at the ends with a 9.5mm steel upstream face sheathing. The weight of the gate is balanced by an open steel box extending across the entire gate length and carrying cast iron weights. The piers for these 4 gates consist of granite or limestone cut stone for the up and downstream noses, gate slots and coping while the body of these piers are faced with granite paving blocks. The remaining gates are constructed with 2 main horizontal girders, the piers are concrete with steel plate protection on the upstream nose and the counterweights are concrete beams.
The operation machinery for raising and lowering the gates is located on an overhead platform supported by steel towers on the piers. The Canadian gates (gates 1 to 8) are hand operated while the American gates (gates 9 to 16) have been automated.
From its beginnings, the development of hydro-electric power in Algoma was a community concern and the individuals who pioneered its growth have a special place in the history of Algoma. The year 1888 saw the first attempt to harness the waters of St. Mary’s Rapids, with a group of Sault Ste. Marie entrepreneurs wanting to not only supplying water and light to the town but also attract new industry to the area. Thus, a canal was created.
The canal, completed in 1894, ended in disaster, with the southeast corner collapsing the first-time water passed through it. Out of money, the project then looked to Francis Clergue and in 1895 work began on a larger canal to provide 20,000 hp instead of the 5,000 hp originally planned.
In 1916, the power plant on St. Mary’s River was bought by The Great Lakes Power Company and under John McPhail’s leadership, construction began and was completed 1918, on a second power canal to increase generation from 4,700 to 15,600 kW. In 1920 the power intake canal was enlarged by removing the center strip between the 2 canals and by 1922, three new 1800 kW generators were added producing 25 and 60 cycle energy.
