Ken Kellar
The risk and cost of a flood outweigh the possible side effects of lower lake levels this summer.
That’s the message that came out of a public meeting held last Tuesday night by the International Rainy-Lake of the Woods Watershed Board’s Water Levels Committee at the Rainy River Community College theatre in International Falls.
The meeting followed a decision by the Water Levels Committee to implement a high flood risk rule curve with regards to maintaining lake levels this spring and summer.
Dam operators use the rule curve to determine how much water to allow to pass through at a time, which, in turn, can affect lake levels.
This is the first time the committee has been able to apply the new high-risk option after the rule curves were updated to allow for it last August.
The Water Level Committee’s U.S. co-chair Samuel Calkins, a colonel with the U.S. Army Corps of Engineers, and his Canadian counterpart, Erika Klyszejko, led the meeting and explained the data taken into consideration when deciding to apply the new rule curve.
Information was monitored throughout the winter and then compared to the data taken from 2018 and 2014, the last severe flood year here.
The data showed this year’s conditions are more in line with those from last year rather than 2014. But the time it takes for snow to melt, coupled with the volume of spring rainfall, will be the greatest contributing factors in whether the area will experience a flood this year.
Calkins said the decision to follow the high-risk curve was, in part, weighing out the pros and cons.
“There’s sort of the competing risks of ‘Hey, are we going to flood?’ or ‘Are we going to be able to fill the lake later in the summer?'” he noted.
“Really what we’re saying is we think the risk of flooding at this point is higher than the risk of not being able to fill the lake.”
The benefit of using the high-risk rule curve is that dam operators will be able to maintain lower lake levels going into the spring in anticipation of more water coming into the lake from its tributaries and other sources.
Should the season turn out to be dry enough not to pose a flood risk, the curve can be returned to its normal setting in order to help the lake levels return to normal.
Klyszejko noted the purpose of the new rule curve is not to prevent flooding entirely, but rather to limit its duration and the extent of any damage.
“If we get another 2014, this will not stop flooding,” she stressed.
“We’re going to monitor the situation, look at the seasonal forecasts as they evolve, and do what we can to reduce the risk, but we don’t promise that we can stop flooding altogether.”
Klyszejko also said deciding to use the high flood risk rule curve every year in anticipation of potential flooding is not a good idea.
“We’ve had input from Fisheries that we can’t do this ‘Oh, maybe it’s going to flood, we’re going to go low’ every year because we may start seeing an impact to fish spawning,” she explained.
“That’s not at all what we want to do,” she added.
“So I think it’s going to be a year-by-year decision.”
The committee also used part of last Tuesday’s meeting to introduce and explain a new adaptive management program that will help it to better monitor and collect data on the effects of changing the rule curve.
Once the program is enacted, a new committee will be able to support ongoing rule curve review, create an inventory of existing monitoring programs, and identify major data gaps and priority monitoring needs in order to better assign funding.
The meeting also included a Q-and-A session, during which those on hand posed questions to the committee on several topics.
These ranged from how to contribute independent data in the future to the impact of lake ice on spring water levels, which Canadian engineering advisor Matt DeWolfe described as already being incorporated into water level data.
According to the Water Levels Committee, the high flood risk rule curve will help the area manage potential high flood waters.
But it conceded that after a certain point, all that’s left to do is to let nature take its course and hope for the best.
“It’s the best information we have right now,” Klyszejko noted.
“But again, it’s really just watching how things melt and how the spring progresses.”
