International Joint Commission (IJC)
More than a century of cooperation protecting shared waters

Great Lakes Water Levels and Flows

Beachscape photo via USGS/Jim Nicholas

Natural factors, including precipitation and evaporation, are among the primary drivers of water levels, along with runoff. The IJC provides oversight at three control structures that impact international water levels and flows in the Great Lakes and St. Lawrence River: in the St. Marys River, the Niagara River, and the St. Lawrence River near the outlets of Lake Superior, Lake Erie, and Lake Ontario. The Canadian and U.S. governments have provided references to the IJC to examine issues surrounding Great Lakes water levels and flows.

Review of the Lake Ontario-St. Lawrence River Order of Approval

Proposal for Lake Ontario and St. Lawrence River Regulation (Plan 2014)

International Lake Ontario and St. Lawrence River Study Board
In December 2000, the IJC established the International Lake Ontario and St. Lawrence River Study Board to undertake the studies needed to evaluate options for regulating levels and flows in the Lake Ontario-St. Lawrence River system. The five-year study was released on May 31, 2006.

Review of Lake Superior Regulation

International Upper Great Lakes Study
In 2007, the IJC estalished the International Upper Great Lakes Study Board to undertake the studies required to provide the IJC with the information necessary to evaluate options for regulating levels and flows in the Upper Great Lakes system to benefit affected interests and the system as a whole.

The study was released in March 2012. The report examines whether the regulation of outflows from Lake Superior through the compensating works and power dams on the St. Marys River at Sault Ste. Marie might be improved to take into consideration the evolving needs of users on Lakes Superior, Huron, Michigan and Erie. The report also examines the potential future impacts of climate change, a management strategy to better anticipate and respond to future extreme water levels, the feasibility and implications of restoring water levels in Lake Michigan-Huron and multi-lake regulation and its impacts throughout the Great Lakes-St. Lawrence system.