'Well-oiled' flood-fighting machine will protect Winnipeg this spring, expert says

Major flooding is expected in the Red River Valley this spring, but Winnipeg should remain reasonably dry thanks to a polished response team, says a civil engineering expert.

Communities north and south of the city, however, will likely need to be diked

Aerial image of flooding around the Morris ring dike in April 1997. (Manitoba government)

Major flooding is expected in the Red River Valley this spring, but Winnipeg should remain reasonably dry thanks to a polished response team, says a civil engineering expert.

But north and south of the city, it could be a much different story.

Since what's called the flood of the century in 1997, the infrastructure around the city has been vastly improved — including a $627-million expansion of the floodway that took 10 years to complete.

As well, a protocol manual has been written on how to deal with the rising water, clearly outlining the roles everyone has to play, like a pro sports playbook.

"So as the Red River rises within the city and hits various water levels, there is literally a protocol manual as to who has to go where and do what, to close what culvert in, and shut down what outflow," said Jay Doering, a civil engineer and flood expert at the University of Manitoba.

"So it's really a well-oiled machine."

Many Manitoba communities are likely in for a major flood fight this year, provincial officials say. (CBC)

Manitoba flood forecasters announced this week that spring flooding in the Red River Valley will be on par with the 2011 deluge — if the weather is average.

That would inundate farmland, communities along the Red River would prepare to or possibly use their ring dikes, and Highway 75 south of Morris could be closed for several weeks.

Low-lying properties in Winnipeg would require sandbag-dike protection and the city would be required to enact other flood-mitigation measures, such as closing off drainage outflows into rivers.

Infrastructure Minister Ron Schuler said Thursday that even if temperatures and precipitation in March are average, the flood levels will match those of eight years ago.

An aerial view of the storm damage at Twin Lakes Beach, along the south shore of Lake Manitoba, in early June 2011. (CBC)

If spring 2019 sees a late-season snowfall, plenty of rain or a rapid melt, this year's flooding could be like that of 2009, when water levels forced the closure of parts of Highway 75 between Winnipeg and the U.S. border, and a number of southern communities were evacuated.

The town of Morris was protected by a ring dike for both the 2011 and 2009 floods, but the water did impact it in another way.

I don't think we want to get into a panic mode at this point but certainly we want to keep watching what's going on.- Morris Deputy Mayor Chris  Hamblin

"The highway's under water so travel becomes more difficult. People are not shopping as much in town. Those things obviously impact the economy of our businesses in town," said Morris Deputy Mayor Chris Hamblin.

"It speaks to the importance of getting Highway 75 raised … so that we're not cutting off our trade access. I don't think we want to get into a panic mode at this point, but certainly we want to keep watching what's going on."

The flood outlook wasn't concerning until last month, Doering said.

"But the month of February has really left a lot of snow, in particular in the Red River Valley. There is about four to six inches of equivalent water sitting over most of the valley," he said.

That becomes a big problem if there is a fast melt, which doesn't allow the water to evaporate or be absorbed into the ground because the frost is still there, Doering said.

"I've always joked that we really only have two seasons in this province — winter and summer. It's kind of like someone flips the switch and we go from relatively cool temperatures to suddenly quite comfortable temperatures," he said.

"And it looks like, if the long-term predictions are true, that it's going to be one of those years. Until that frost comes out there's no ability for the ground to absorb that moisture."

Overland flooding, often caused by ice jams, will likely be a concern this spring. (Gary Solilak/CBC)

Something else Doering is watching is the thickness of river ice, which is about a meter in some areas north of the city due to the extreme cold temperatures in January and February.

​​Doering says the issue of ice jams north of Winnipeg could be one of the biggest threats.

As snow and ice start to break up into chunks along rivers, the ice can fuse together in narrow areas or at bends along the river's path. Areas north of Winnipeg are most susceptible.

The jams then act like dams, clogging the river and causing the water to back up, spilling over the banks and causing flash flooding.

Larry Johannson, the mayor of Selkirk, north of Winnipeg, said Thursday's flood forecast was "worrisome, very, very worrisome."

"There's a lot of snow and there's a lot of ice and the weather can change on a dime. It could be devastating," he said.

If it jams up and doesn't move, we're all in trouble here- Selkirk  Mayor Larry  Johannson

The province has sent machinery onto the river north of Selkirk to cut and break up the ice in preparation for the melt.

If that solid bed of ice isn't weakened enough to move out when the river starts to thaw, all the water flowing north will slam into it, like hitting a wall, then spread sideways onto the land.

​"If it jams up and doesn't move, we're all in trouble here," Johannson said.

In addition to Selkirk, Johannson is concerned about the neighbouring communities of St. Andrews and St. Clements, where ice jams have caused emergency evacuations — sometimes in the middle of the night — in the past.

"When they get flooded there, it takes no prisoners," he said. "We don't want any lives at risk there."

Comments

To encourage thoughtful and respectful conversations, first and last names will appear with each submission to CBC/Radio-Canada's online communities (except in children and youth-oriented communities). Pseudonyms will no longer be permitted.

By submitting a comment, you accept that CBC has the right to reproduce and publish that comment in whole or in part, in any manner CBC chooses. Please note that CBC does not endorse the opinions expressed in comments. Comments on this story are moderated according to our Submission Guidelines. Comments are welcome while open. We reserve the right to close comments at any time.