Posted Jan 17, 2013 By Laura Mueller
EMC news – Four months after a large sinkhole closed the Jean D’Arc off-ramp of highway 174, the city is agreeing with five recommendations to prevent similar incidents in the future.
On Sept. 4, 2012, a storm sewer underneath the off-ramp collapsed during rush hour. A section of the road was closed for repairs for several days.
An independent engineering report on the road collapse was scheduled to be presented to and discussed by the city’s environment committee on Jan. 15.
A statement released by the city says the municipal government agrees with all the findings and recommendations and has already begun to take steps to implement the five suggestions.
In the statement, city manager Kent Kirkpatrick said the city recognizes the “seriousness” of the sinkhole event and it will continue to strengthen protocols to help prevent similar incidents.
“The city is committed to doing everything in its power to protect public safety,” Coun. Maria McRae, chairwoman of the environment committee, said in a city press release.
“This report along with the city’s new comprehensive asset management program will help to ensure that staff implement necessary measures so that our roads are safe and to ensure that residents can keep travelling on them without worry,” Orléans Coun. Bob Monette said in the statement.
He was referring to a document city council approved in October that outlines the condition and a maintenance schedule – with costs – to repair and replace things such as roads, pipes and bridges.
Added to that will be more inspections and monitoring in situations where the city identifies a pipe that needs replacement so it can be fast-tracked.
Those steps include talking with the Ontario government about establishing province-wide inspection requirements for critical sewers, similar to what Ottawa is doing with its new asset management practices. The city’s approach prior to the sinkhole incident is similar to what cities of a comparable size do, the report found.
The five recommendations offered by independent engineering firm BMRoss are:
- To expand the definition of a high-risk storm sewer to include the probability of a pipe’s collapse and its consequences
- To examine all “high-risk” storm sewers as soon as possible and have the examinations reviewed
- To asses the quality of the data used to inform the city’s asset inventory and obtain better data where necessary
- To use in-person inspections to supplement the video inspections the city already does
- To include a discussion of the consequences of not proceeding quickly on capital projects in reports
The recommendations were released in December and the city’s response was posted in advance of the Jan. 15 meeting during which the environment committee was to discuss the findings.
BMRoss concluded the root cause of the sinkhole was that the degree of risk was not identified and acted on before it began to degrade.
While a crew was inside the pipe throughout the day using an excavator and a skid-steer loader to install lights and remove rocks and debris, the review found there was no way to determine if those activities accelerated the pipe’s collapse. It was already known the collapse was possible or imminent – that’s why the repairs were scheduled – but it is possible the timing of contractors working in the pipe the day before it collapsed is simply a coincidence, the report concludes.
A video shot inside the pipe on Aug. 17 showed the pipe was in very poor condition, the report says. Within a day, city staff had expanded the type of work to be done on the pipe, but the city should have gone further, BMRoss’s report states.
“In our opinion, the immediate need for a more robust assessment of the pipe was not understood, identified or communicated,” the report reads.
Part of the reason the condition of the pipe wasn’t considered more of an emergency is because there was no prior inspection to compare with the video footage because the city was only inspecting those types of pipe every 15 years. An inspection is said to have been done in 1997, prior to amalgamation, but no report was available from that inspection.