Great Lakes Diversions

The major diversions in the Great Lakes basin that affect water levels are diversions into Lake Superior at Long Lac and Ogoki, the Chicago diversion out of Lake Michigan and a diversion between lakes Erie and Ontario through the Welland Canal.

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Great Lakes Diversions

The major diversions in the Great Lakes basin that affect water levels are diversions into Lake Superior at Long Lac and Ogoki, the Chicago diversion out of Lake Michigan and a diversion between lakes Erie and Ontario through the Welland Canal.

Learn More

International Lake Superior Board of Control

The International Lake Superior Board of Control is responsible for regulating the outflow of Lake Superior and managing the control works on the St. Marys River.

About the Board

News Releases

The gate setting of the Compensating Works will be increased on Tuesday, May 6, from the current setting equivalent to approximately one-half gate open to a setting equivalent to approximately one gate open, to meet the Plan 2012-prescribed flow in May in consideration of capacity restrictions at...

The gate setting of the Compensating Works will be maintained at the typical winter gate setting (Gate #1 and Gates #7 through #10 open 20 cm each) equivalent to approximately one-half gate open. The average St. Marys Rapids flow in April is expected to be approximately 85 cubic meters per second (3...

The Board expects the total St. Marys River flow in March to be 1,610 cubic meters per second (56,900 cfs), as prescribed by Regulation Plan 2012. Actual hour-to-hour and day-to-day flows may vary depending on hydrologic conditions, as well as variations in flow from the hydropower plants.

February 25, 2025

Water levels in each of the Great Lakes, except for Lake Erie, are currently below long-term monthly averages. Actual spring and summer water levels will depend primarily on weather and water supplies during the spring and summer months.

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