Sinkhole opens up in Pasqua-Parliament intersection

Regina has another sinkhole underfoot.

Just over a month after a hole appeared in the middle of the intersection of Avonhurst Drive and Elphinstone Street, another sinkhole has developed at the intersection of Pasqua Street and Parliament Avenue.

Pat Wilson, the City of Regina’s director of water, waste and environmental services, said Tuesday that a sewer backup occurred in the vicinity of the intersection on Thursday.

Workers cleared that blockage, but the sewer plugged again. They cleared it a second time and found a great deal of dirt in the sewer, prompting the city to monitor the location.

While they did, a sinkhole opened up.

Wilson said the city hopes to have the hole filled by the end of the week — but it could take longer.

The City of Regina’s Pat Wilson discusses a sinkhole in Regina on Aug. 6, 2019. (Evan Radford/980 CJME)

“This is a very complex location,” she said. “There are several different neighbourhoods where the flow comes into that particular location, into the manhole there, that makes the whole issue of pumping around that while we do a repair very complex.

“As well, there’s a number of other utilities that are right in proximity to that site. That makes planning extremely important for this location.”

Sewer service has been restored in the area, but traffic will be impacted.

“We appreciate the patience of residents while we go through this work,” Wilson said. “We know that it is an inconvenience to have a major intersection closed and we don’t do that lightly, but it is the best thing to do to make it safe and to make sure that it doesn’t become a bigger issue.”

The newest sinkhole is smaller than the one at Avonhurst and Elphinstone, at least in terms of its width; Wilson said the hole is about as wide as a traffic barrier.

But the 24-inch sewer pipe is deep in the ground. Given that passing vehicles could cause vibrations that could expand the hole, the city is looking to set up detours.

Wilson said the sinkhole likely was caused by drier-than-normal soil around the pipe as well as a buildup of corrosive gases inside the pipe that likely affected the concrete.

“The combination of dry soils putting pressure on those pipes and then some impact on the structural stability of that pipe over time causes part of that issue,” she said.

Flushing out the sewer lines wouldn’t be practical due to the amount of water required, Wilson said. Recent rainfall helped, but she noted the dry summers in recent years are having an impact — as evidenced by two sinkholes in the span of a month.

“Two is something that we are concerned about and we will be doing more inspecting and exploring, looking for possible situations,” Wilson said. “It’s not necessarily a trend at this point, but it does concern us.”

Wilson said her department will take into consideration the formation of sinkholes as it completes its wastewater master plan for Regina city council to examine.

— With files from 980 CJME’s Evan Radford