Photo by Mico Mazza

Another sinkhole has made an appearance in Ottawa, this time right by the University of Ottawa.

The hole, measuring about eight metres wide and 12 metres deep, opened up early Friday, Feb. 21 on Waller Street on the south side of the intersection at Laurier Avenue. The collapse happened at the construction site where crews have been digging one of the light rail tunnel entrances, only steps away from the Arts and Simard buildings and the Laurier bus station.

Authorities were forced to close one lane of Laurier eastbound between Waller and Queen Elizabeth Drive, and OC Transpo had to shut down the nearby station and reroute its buses. Residents at 50 Laurier Avenue had water and sanitary services disrupted.

Workers filled the hole by midday Saturday, and traffic reopened by Monday.  The hole was reopened Tuesday to make repairs.

There were no reported injuries from the collapse.

Deputy city manager Nancy Schepers initially said during a technical briefing Friday that the cause of the sinkhole was unknown.

“We can only confirm that it was directly above where tunnel excavation was occurring, and at this point we cannot confirm its root cause,” she said.

City officials later said it was probably LRT tunneling that caused the collapse. Schepers said that “all steps are being taken to first protect the public and all physical assets in the immediate area.”

She added that the sinkhole is solely the concern of the Rideau Transit Group (RTG) unless it is discovered that the city was at fault, due to the $2.1-billion contract between the two.

Tim Stewart, RTG’s construction director, said in a statement that a digging crew noticed dirt falling into the tunnel at approximately 10 p.m. on Feb. 20. Tunneling stopped while officials were notified.

After the collapse, RTG crews used concrete to reinforce the area and allow investigation.

Tunneling, which is supposed to be ongoing 24 hours a day, has been put on pause until it’s safe to resume.

Feb. 21 was the one-year anniversary of the Confederation Line project, and the press conference scheduled to celebrate it was cancelled.