Water Levels: Now Versus Then, Lessons Learned

What a difference a year makes. This time last year, the Lake Ontario level was 31 inches above the average and 3 inches above the record high, which was set in 1952. Widespread flooding was occurring in the Ottawa River Valley, Montreal, and along the shores of Lake Ontario. Newspapers and social media posted photos of canoes and row boats floating down what only weeks before had been streets filled with automobiles. Homes and businesses were full of water. It was what has been referred to as “A Perfect Storm” or “A Hundred Year Event”.

Public questions landed in the lap of the International Joint Commission (IJC) (the binational organization that manages boundary water disputes) regarding the January 2017 implementation of its new water regulation plan, Plan 2014, that had only months earlier replaced the 50+year old Plan 1958D. As the saying goes, “Timing is everything.”




Daily Lake Ontario Levels




A coordinated response to this unprecedented situation was quickly organized and implemented. From late May through September of last year, the entity charged with implementing Plan 2014, the International Lake Ontario – St. Lawrence River Board (Board), could deviate from the rules of Plan 2014 due to the unprecedented highwater levels. Due to the widespread flooding that was occurring along the shores of Lake Ontario, the Board released record- setting outflows to provide relief to the shoreline property owners. These extraordinary water and weather events brought together stakeholders working to minimize impacts to shoreline landowners, not only on the shores of Lake Ontario but also for those in Montreal and the Ottawa River Valley. Commercial navigation interests aided in this relief by having vessels navigate at the highest possible outflows from Lake Ontario through the St. Lawrence River. The Seaway made significant contributions to this effort. It was necessary for the Seaway Corporations to implement several measures to mitigate the impacts of the high-water velocities to ensure continued safe navigation in the Seaway. Vessel transit times increased due to these mitigation measures. Due to the efforts of the Board, the stakeholders, and primarily, the weather, water levels in the Fall were three feet lower than those experienced the Spring.

That is the old news — so what is expected for 2018?

Near the end of 2017, under Plan 2014, the Board continued to release high outflows to lower the level of Lake Ontario to reduce the risk of flooding for this year. The several months of high outflows under Plan 2014 at the beginning of this year coupled with favorable weather conditions (unlike the torrential, almost constant, rainfalls of 2017) have resulted in water levels closer to average.

For the week of May 24, 2018, the outflows from Lake Ontario continued to be high and Lake Ontario’s level is 22 inches below the level for this time last year. According to the Board, the risk of significant flooding either upstream or downstream is low. As stakeholders learned last year, the most significant factor in determining whether flooding will occur is ultimately by the weather.

As I walk along the Eisenhower Lock in the mild 70-degree weather of a delightful May 2018 day with no clouds in the sky, let alone a rain cloud, that point hits home — we could have any water regulation plan in place, but water levels are ultimately dependent on the predilections of the weather. (I am also reminded that Mother Nature has a say over when we close the locks; however, that is a story for another day). We can only control so much.


SOURCE: SLSDC, Seaway Compass Spring 2018