1.2 C
Wednesday, November 30, 2022
Lake Ontario water level remains much higher than normal into winter

Water levels in Lake Ontario have dropped significantly since the record high peak in June, but they’re still well above average for this time of year.

Back in June, the water level peaked at an all time high of 75.92 metres.

At the same time, “the Niagara River hit a record high average flow since records started being kept in 1860,” says Frank Seglenieks, a water resources engineer for Environment & Climate Change Canada.

“It was the highest flow ever seen on the river, at 8,0559 cubic metres per second. The average is in the low 7,000s.”

 As of Nov. 21, the level dropped to 75.02 metres, but it’s still the highest level for November since 1945, said Steve Miller, senior manager of water resources for the Niagara Peninsula Conservation Authority.

“The water level is still 49 centimetres (1.6 feet) above average on Lake Ontario, and Lake Erie is 68 centimetres (2.2 feet) above average.” 

There are no controls on the flow of water from Lake Erie into Lake Ontario, and the only point of control for letting water out of Lake Ontario is at the Moses-Saunders Power Dam in Cornwall.

“Outflows through the dam are at the highest they’ve been for this time of year since 1986,” said Rob Caldwell, Canadian secretary for the International Lake Ontario-St. Lawrence River Board, as efforts continue to reduce water levels in Lake Ontario.  

“We anticipate high water levels in the Great Lakes going into spring,” said Miller.

“Even with average conditions, levels will still remain high going into early spring. It would take very dry conditions to get to average levels by spring,” added Seglenieks. 

Several factors will influence just how high the water will be.

“This time of year, evaporation begins. When we have the greatest contrast between water temperature and air temperature, we get evaporation, and that helps lower water levels,” explained Seglenieks.

A winter with heavy snowfall and prolonged ice cover would contribute to higher levels in the spring, while a milder winter with low precipitation would point to lower levels.

When it comes to predicting whether there will be repeated flooding in the spring and summer of 2020, “my crystal ball is fuzzy, there are just too many factors,” said Caldwell. 

But “a lot has to happen for a repeat, and the chance is low. It takes a perfect storm of factors, including high inflows from Lake Erie, ice in the river, snow melt, wet precipitation, and flooding in the Ottawa River,” which puts constraints on how much outflow is safe. 

Over the winter, outflow will be kept at the highest level safely possible, Caldwell said.

“We have the green light from the International Joint Commission to look for every window of opportunity to go above and beyond to release as much as feasible in the months ahead. We’ll do everything we can.”