Moses-Saunders Dam

Flexibility in setting Lake Ontario outflows to continue


The International Lake Ontario – St. Lawrence River Board (Board) announced today that, in directing Lake Ontario outflows, it has been given the ability to continue deviating from the flow specified by Plan 2014.

The Board has had authority to deviate from Plan 2014 since May 7th, after Lake Ontario rose above the high water trigger levels specified in a provision known as criterion H14. In light of the present extraordinary circumstances, the International Joint Commission (IJC) has given the Board authority to deviate from Plan 2014 even after Lake Ontario falls below the criterion H14 trigger levels.

The new authority extends until June 2020 when Lake Ontario is forecast to reach its seasonal peak.   

From the International Lake Ontario – St. Lawrence River Board:

We appreciate the IJC's decision to authorize the Board to continue to deviate from Plan 2014 after Lake Ontario water levels fall below the criterion H14 upper trigger levels.  The Board has been reviewing data from the past three years to better understand when potential opportunities to deviate from Plan 2014 might be available over the next several months, and what the effects of such deviations might be on water levels and interests throughout the Lake Ontario - St. Lawrence River system.

Forecasts indicate that Plan 2014 outflows will be very high and at or near maximum values for several months.  The IJC's decision will allow the Board to further increase outflows when opportunities arise considering the impacts that these flow increases will have on other interests of the system.  These opportunities are expected to remove a small amount of additional water from Lake Ontario to reduce the risk of high water in 2020.  The Board stresses that while an outflow strategy can influence water levels, the main driver is weather, especially when wet conditions are as extreme as they were in 2017 and 2019. We will continue to communicate the outflow strategy as the Board identifies opportunities to deviate from Plan 2014.


Across the Great Lakes, water levels remain high and are forecast to continue to be high through at least the winter.  Whether they remain high next spring will primarily depend on weather and water supplies.  Lake Ontario is the only Great Lake that has a chance of getting near or returning to its long-term average by spring 2020.  This possibility is directly related to the influence that water regulation can have on water levels if the conditions to accommodate high flows in the St. Lawrence River occur.   

The Board, in conjunction with its staff, continues to monitor conditions on an ongoing basis. Information on hydrologic conditions, water levels and outflows, including graphics and photos, are available on the Board’s website and posted to the Board’s Facebook page at (English), and more detailed information is available on its website at


Rob Caldwell: (613) 938-5864;

Andrew Kornacki: (716) 879-4349, (716) 352-8669;


The International Lake Ontario – St. Lawrence River Board specifies the outflows from Lake Ontario, according to Plan 2014 as required in the 2016 Supplementary Order from the International Joint Commission. This plan was agreed to by the United States and Canada in December 2016 in an effort to improve environmental performance while maintaining most of the benefits provided to other interests by the previous Plan 1958-D, which was in use since 1963. In determining outflows, the Board, in conjunction with its staff, pays close attention to water levels in the Lake Ontario-St. Lawrence River system and on the Great Lakes upstream, and to the effects on stakeholders within the basin.

Water levels vary from year-to-year and throughout the year depending on weather and water supply conditions.  Such variations benefit coastal wetlands and are critical to a healthy lake environment, but may at times and depending on individual circumstances increase the vulnerability of shoreline structures and reduce opportunities for recreational boating activities.  The Board urges everyone to be prepared to live within the full range of levels that have occurred in the past and of those that may occur in the future.  Based on historical observations and projected future conditions, at a minimum, Lake Ontario water levels are expected to range from a high of 75.88 m (248.9 ft.) to a low of 73.56 m (241.3 ft.) at infrequent intervals.  However, it is also recognized that future climate conditions are uncertain, and more extreme water levels may be reached and these extremes may occur more often.  Levels on the St. Lawrence River tend to vary more widely than on Lake Ontario.  Also, these levels do not include the varying local effects of strong winds and wave action that significantly increase or decrease local water levels on both the lake and river, with temporary changes of over half a meter (two feet) possible in some locations.

For more information, please see the Board’s website ( and Facebook page ( receive a weekly email about water levels and flows in the Lake Ontario–St. Lawrence River system, please send a blank e-mail message to with the word ’subscribe’ in the title and body of your message.