Lake Ontario water levels forecast to be above normal, but below 2019

Staff Reports Posted 8 April 2020 at 9:02 pm

Photo by Tom Rivers: The lighthouse at Golden Hill State Park in Barker is pictured on Aug. 7, 2016 during a sunset on Lake Ontario.

The board that manages water levels at Lake Ontario expects the water levels this spring to be higher than normal for Lake Ontario, but shouldn’t surpass 2017 and 2019, years of destructive flooding along the southshore.

Spring is a critical period for Lake Ontario outflow regulation, the International Lake Ontario-St. Lawrence River Board said. That group is closely coordinating with the Ottawa River Regulation Planning Board during the Ottawa River snowmelt to have the highest outflow from Lake Ontario while balancing impacts upstream and downstream on the St. Lawrence River.

Inflows from Lake Erie, precipitation, runoff, snowpack, along with the snowmelt in the Ottawa River basin are the primary drivers of water level fluctuations this time of year, the International Lake Ontario-St. Lawrence River Board said in a news release.

These conditions are different each year, made more challenging by dynamic spring weather, making it difficult to accurately forecast water levels.

Last month there was a record outflow from Lake Ontario, the third straight month of record-high outflows under the International Lake Ontario – St. Lawrence River Board’s deviation strategies.

The delayed opening of the St. Lawrence Seaway, in combination with seasonable weather and favorable conditions in the Ottawa River basin, allowed the Board to remove an extra 3.46 cm from Lake Ontario. This would not have been possible had the Seaway opened on March 20.

Lake Ontario had been rising gradually for the past couple of weeks, but very slowly recently.  As of April 6, the level was 75.26 m (246.92 ft). This is 42 cm above average, but 38 cm below the record-high for this time of year.

It is important to remember that there is still a lot of snow to melt and the possibility of active and wet spring weather in the coming weeks.  Even at the current levels, storms and strong winds can also cause severe damages, and it is always good to have a coastal resiliency plan in place, the International Lake Ontario – St. Lawrence River Board said in its news release.

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