Lake Ontario St. Lawrence River Plan 2014


The International Joint Commission has managed the flow of water at the Moses-Saunders hydropower dam since 1960. The management of water flows influences water levels on Lake Ontario and in the St Lawrence River as far downstream as Lake St. Pierre. Water levels and flows are primarily determined by natural factors, such as precipitation, evaporation and wind, but the influence of water flow management has provided substantial benefits to the region by reducing flooding, reducing erosion on the Lake Ontario shoreline and providing more favorable conditions for water intakes, recreational boating, commercial navigation and hydroelectric power production. However, water levels and flows are being managed according to criteria that were set more than 50 years ago. Plan 2014 sets a new standard for managing water levels and flows that is based on careful consideration of the needs of all interests the basin – now and in the future.

The need for change

Variable ice cover, increased storm intensity and warmer temperatures are changing how water levels and flows impact coastal communities, recreational boating and commercial navigation, drinking water, hydropower production, and the system’s ecological health. The current water management criteria are based on the limited range of Lake Ontario water supplies that were recorded from the 1860s to the 1950s. These criteria have created an unrealistic expectation that Lake Ontario water levels can be maintained within a four-foot range (1.22 meters). Over 50 years of experience, including the low levels of 196-65 and the high levels in the mid-1970s, 1993 and 1998, have shown that it is not possible to keep the lake within this range under more wide-ranging water supply conditions.

Ecosystem health was not considered in the 1950s when decisions were made to artificially compress the natural variability of the basin’s waters. Extensive research shows the regulation criteria have compressed the range of water levels to the point of degrading more than 60,000 acres of wetlands on the shoreline of Lake Ontario and the upper St. Lawrence River. These wetlands provide vital habitat for the native plants, birds, fish and other animals.

Allowing more natural variations in water levels, while moderating extreme levels, can help restore a healthy wetland ecosystem on the lake and upper river.

Plan 2014

After exhaustive consideration of alternative plans, the Commission concludes that Plan 2014 offers the best opportunity to reverse some of the harm while balancing upstream and downstream uses and maintaining nearly all of the reduction in coastal damages provided by the current plan. Plan 2014 incorporates significantly increased knowledge gained through the Commission’s five-year landmark study refined by additional analysis by U.S. and Canadian experts and important contributions from Quebec, Ontario and New York State, as well as from municipal governments, indigenous governments, and shipping, fishing, recreational, riparian, environmental and other interests that depend upon the St. Lawrence River and Lake Ontario.

Plan 2014 is designed to provide for more natural variations of water levels of Lake Ontario and the St. Lawrence River. It has high and low trigger levels for Lake Ontario according to the seasonal nature of water supplies. When water levels reach the triggers, the flows will be set to provide all possible relief to affected interests instead of following the regulation plan.

Upstream of the dam, Plan 2014 will produce more variability in levels without much change in the overall range of water-level fluctuations. Downstream in the lower river, the variability in water levels will not change significantly under Plan 2014 compared to the current plan.

Plan 2014 will benefit ecosystem health, moderate extreme high and low levels, better maintain system-wide levels for navigation, frequently extend the recreational boating season and slightly increase hydropower production. More natural year-to-year variation in water levels improves ecosystem health.

Thriving wetland habitats support highly valued recreational opportunities, and provide nurseries for fish and wildlife. Every regulation plan represents a balance of managing the impacts of fluctuating water levels that affect all of the different interests in the basin.

After listening to basin interests for many years, the IJC is confident that Plan 2014 is the best plan for the full range of interests that depend on Lake Ontario and the St. Lawrence River system in both Canada and the United States.