Slumping slope in Saskatoon continues to get worse

The street slumping near Saskatchewan Crescent and 16th Street is continuing to get worse.

Saskatchewan Crescent and 16th Street remains closed with massive crack splitting the roadway

Part of Saskatchewan Crescent is blocked off near the riverbank in Saskatoon. (Don Somers/CBC)

Folks walking along the eastside of Saskatoon's riverbank can't help but stop and gaze at a massive crack in the middle of Saskatchewan Crescent, the latest Saskatoon slope failure.

Shortly after the snow melted this spring, homeowners along Saskatchewan Crescent East between 16th and 17th streets, near the east end of the University Bridge, have slowly watched the road in front of them slide away into the riverbank.

Right now a massive dip in the roadway has split the street in two, with one part of the street sitting a couple of feet higher up than the other.

The damage has led to a road closure to all traffic along Saskatchewan Crescent East. Slumping also closed a portion of the Meewasin Valley Authority trails and the sidewalk along the east riverbank.
The street is cracking along the slumping slope by Saskatoon's riverbank near the east end of the University Bridge. (Chanss Lagaden/CBC)

On March 21, Saskatoon's city council awarded an engineering contract to Golder Associates Ltd. to develop a remediation plan for the 16th Street riverbank slope instability.

Jeff Jorgensen is the city's general manager of transportation and utilities. He said engineers at the site said the slope is sliding a lot quicker than they thought earlier in the season.

"We are watching this site and a number of other sites along the east riverbank and this one is by far the quickest moving one and the closest to any property," Jorgensen said.
The road is slumping faster than anticipated along the riverbank close to Saskatchewan Crescent E. (Chanss Lagaden/CBC)
But as far as any risk to homeowners, Jorgensen said consultants and engineers monitoring the site believe there is no risk for homeowners in the area at this time, but if something changes, the level of risk to homeowners could change as well.
This map shows areas in Saskatoon currently slumping. (CBC)

What's causing the slope failure?

Jorgensen said the cause of this recent slide is consistent with other slope failures in the city, and he chalks it up to the geometry of the slope.

"Basically the steepness of the slope, slope properties and the ground-water pressures from below, those are the things driving this," Jorgensen said.

The contract with Golder Associates Ltd. city council passed in March states that a design solution for the area won't be developed until the end of May, with construction in the area to fix the slope starting in September.

Jorgensen said it is the least aggressive timeline the city can hit, but he said they are doing everything in their power to speed up the process.

"It will be an extensive construction project for sure and I think if you look at some of the other work we've done in recent years along the riverbank, it would be similar to that type of work," he said. 

City should stop developing along riverbank

Cherie Westbrook is a hydrologist with the University of Saskatchewan. She said homes should not be placed so close to the riverbank. (Don Somers/CBC)

Cherie Westbrook, a hydrologist at the University of Saskatchewan, said a string of wet years in Saskatoon has saturated the groundwater system, causing the layer of sand on top of the riverbed to weaken. That weakening causes slumping along the riverbank.

She said the city needs to stop developing so close to the riverbank.

"Within the city limits we've had about 100 slides in the last 100 or so years, so this is an ongoing problem. This is what happens to riverbanks," Westbrook said. "These areas were designated as areas we shouldn't be developing because things like urbanization only compound the problem."

She recommends the city use its riverbanks for low-cost recreational projects, not for homes.