This Board was established by the International Joint Commission in its 1914 Order of Approval granting permission for increased hydropower development in the St. Marys River. The Board’s duties include setting Lake Superior outflows, and overseeing the operation of the various control works. Activities related to these responsibilities include: conducting studies to develop and improve the regulation plan; monitoring repairs and maintenance of the control facilities; and directing flow measurements in the St. Marys River for the purpose of determining the discharge capacities of the various control works.
The Board provides the Commission with advice on matters related to: adverse hydrologic conditions on the lakes; modification of the control facilities; and levels and flows in the St. Mary’s River, including the environmentally sensitive St. Mary’s Rapids. The Board meets at least twice yearly, semi- annually provides the Commission with a report on its activities, and annually meets with the public.
Water flows out of Lake Superior through the St. Marys River into Lake Huron. Near the cities of Sault Ste. Marie, Michigan and Ontario, the St. Marys River falls about 6 metres (20 feet) in a distance of 1.2 kilometres (0.75 mile) as it passes the St. Marys Rapids. Since 1797, when the first lock was built to allow boats to bypass these rapids, various navigation and power structures have been constructed along the river.
Today, the water from Lake Superior flows through a collection of structures that stretch across the river. These works include three hydropower plants, five navigation locks, and a gated dam at the head of the rapids known as the Compensating Works. The release of water from Lake Superior through the various structures has been completely regulated since the completion of the Compensating Works in 1921.
In its 1914 Order of Approval allowing increased hydropower development in the St. Marys River, the International Joint Commission established the basic objectives for and limits to the regulation of Lake Superior’s outflow. The conditions for regulation given in the original Order acknowledged the needs of various interest groups on Lake Superior and the St. Marys River, including navigation, hydropower and riparian owners.
Since 1978, the Commission has issued several supplements to the original Order of Approval. As a result, the Order now specifies that the level of Lakes Michigan and Huron must also be considered when determining the outflow from Lake Superior. In addition, the Order addresses concerns for the fishery in the rapids.
Various regulation plans have been developed and used to determine Lake Superior outflows. Each of these plans has adhered to the operating conditions contained in the Commission’s Order. The main objective of the present regulation plan is to determining a flow that will bring the levels of Lake Superior and Lakes Michigan and Huron to nearly the same relative position within their respective ranges of actual historic levels. At the same time, the plan tries to prevent the level of Lake Superior from rising above or falling below certain water levels specified in the Order. The plan also contains provisions to safeguard against high levels in the harbor below the locks, provides a fixed minimum release, limits winter flows, and employs a forecast of future water supply conditions.
The ability to regulate the outflow from Lake Superior does not mean that full control of lake levels is possible. This is because the major factors affecting the water supply to the Great Lakes — over-lake precipitation, evaporation and runoff — cannot be controlled; neither can they be accurately predicted over the long term.
The regulated release of water from Lake Superior is made through the various structures located on the St. Marys River. The allocation of flow to these facilities is determined monthly, based on the outflow specified by the regulation plan and the conditions given in the Order of Approval. This water is used for domestic water supply, navigation through the locks, hydropower production, and to maintain fish habitat in the rapids.
The International Lake Superior Board of Control is a two- member board, one from each the United States and Canada. The member for the United States is from the U.S. Army Corps of Engineers. The member for Canada is with Environment Canada. Members serve in both their personal and professional capacities.
To assist the Board in carrying out the Commission’s directives, each member has a Secretary, a Regulation Representative, and an On-Site Representative. The Regulation Representatives provide technical support to the Board. The On- Site Representatives oversee the operation of the control structures on the St. Marys River.
For more information, please contact:
Mr. John W. Kangas
U.S. Army Corps of Engineers
Great Lakes Center
231 S LaSalle Street, Suite 1500
Chicago, IL 60604
Mr. Rob Caldwell
Great Lakes – St. Lawrence Regulation Office
111 Water St. East
Cornwall, ON K6H 6S2