City of Regina crews expect to spend the next three days working to fill in a massive sinkhole that opened up Monday afternoon at a busy intersection.
Crews assembled Tuesday morning at the intersection of Elphinstone Street and Avonhurst Drive, but the backhoe brought to the job site had to be switched out for a larger one.
The hole is estimated to be over 7.5 meters, or 25 feet, deep. According to city engineers, this is likely the largest sinkhole Regina has ever seen.
On Tuesday afternoon, The city’s director of water, waste and environmental services, Pat Wilson, said they will not know a firm cause until crews are able to get down to the bottom of the hole.
READ MORE: Sinkhole nearly swallows truck in Regina
However, the city suspects a sewer trunk line ruptured and soil began to flow through the pipe. Wilson said normally water will flow to the surface through Regina’s clay soil when this happens, but that wasn’t the case this time.
“Even with an inspection of the pipe, we wouldn’t see outside of the pipe and therefore wouldn’t see whether there was a void in the soil,” Wilson said.
“So when it’s underground it’s very difficult to know something is happening until it gets to the surface.”
The trunk line is a concrete pipe that is approximately 62-years-old. Wilson said ground shifting may have played a role in the suspected break that created the sinkhole.
The pipe’s lifespan is around 70 years, and Wilson said this is why they are doing relining work on concrete pipe in areas like 15th Avenue.
No one was injured when the sinkhole formed suddenly, but a truck nearly fell in.
Tuesday morning, Regina’s newest pit became a fairly popular site for onlookers.
“I saw it on Facebook and Instagram, thought I’d check it out with my mom,” Brianna Beauchamp said.
Dale Winters used to live in the area, and walked down with his wife to see the hole. He’d never seen anything like it before.
“There’s a channel just on this side of the railway track. I’d wondered if it had something to do with that,” he said.
The channel likely did not contribute to the sink hole, but it was affected by it.
Wilson said the ruptured sewer line saw waste leak into a nearby storm channel. The Water Security Agency has been notified, and the situation is being monitored.
“Because of the large rain event that also happened that will have diluted that considerably, which is beneficial in this particular case,” Wilson said.
“The natural water system is also a very effective water cleaning system. The normal process is to get it to the waste water treatment plant.”
The sewer line is still active in the area thanks to a bypass running along the street.
The city is working with SaskPower and SaskEnergy to identify transmission lines as they do excavation work to fix the issue. They do not expect nearby customers to lose service during the work period, but detours are in place.