Ottawa Mayor Jim Watson said the culvert that collapsed and caused a sinkhole two months ago appeared to be in "very bad" condition in an inspection video from a year earlier, but said he would reserve judgment until an independent review was complete.

Watson said he's only seen five seconds of the footage CBC News showed last week of a routine inspection of the storm sewer a year earlier that showed the steel pipe was severely corroded. But what he saw appears to have made an impression.

"You know obviously the condition looks very bad, and I'm not an expert in judging how bad it was, and how close to failure it was. Obviously it was at a state of disrepair to the point that it needed to be replaced, and that's why we moved in, and obviously we moved in too late," he said.

The storm sewer failed two months ago, causing a sinkhole to form in the eastbound lanes of Highway 174 near the Jeanne d'Arc exit on Sept. 4.

Man who drive into sinkhole wants OPP probe

An Ottawa man, Juan Unger, was driving home from work when his car fell into the sinkhole. He managed to pull himself out with the help of two bystanders.

Earlier this week Unger accused the city of "criminal negligence" after he viewed the video.

Watson said given the potential for legal action he said he would not make a judgment on whether the city acted fast enough until after an independent study by B.M. Ross and Associates is completed in December.

"That's why we did an independent study so it's taken out of the hands of the staff, and we have an honest and realistic assessment of what went wrong, what happened in the past and how we can do better in the future," said Watson.

City staff have identified two other culverts under Highway 174 — one west of the Montreal Road exit, the other west of Orleans Boulevard — in similar shape to the one that collapsed. Those culverts are slated for repair this winter.