An early April rainstorm that washed away a massive section of Line 5 in Essa Township, a couple of kilometres south of County Road 90, will cost the municipality between $330,000 and $450,000 to repair.
It could have been more, almost double, but the township decided to repair the collapsed roadway using internal resources, saving upward of $300,000 on third-party contractors.
Essa council approved the repairs at Wednesday night’s council meeting.
The timelines for when the repairs will begin and end was not immediately available, however.
According to his report to council, public works manager John Kolb said the slope failure occurred following a heavy rainfall on April 12 that lasted almost 24 hours.
The initial failure was about 50 metres in length, he said, and was compounded by an additional landslide that extended the damage another 20 metres.
The underlying culvert, which conveyed a small creek below the roadway and is about 90 metres long, was also damaged at both ends.
Kolb said road staff spent two days — April 12 and 13 — trying to temporarily stabilize the failure.
A site visit and preliminary assessment were conducted by GEi, a consulting firm, on April 15.
Remedial work started that same day and included the removal of the failed sections of the embankment and exposing the buried culvert ends.
According to Kolb, more than 22,000 cubic metres of material were required to create two access roads parallel to the Line 5 to provide access to the culvert, which was buried 10 to 12 metres deep.
“These operations utilized the entire roads department manpower in order to save on the overall cost,” said Kolb, noting the work done by township staff would have cost $200,000 to $300,000 if done by a third-party firm.
On May 30, CEi inspected the culvert for structural integrity and to evaluate the available options.
On June 14, township staff received the inspection report and three options to repair the damage.
The first option would consist of replacing both ends and repairing the broken seam near the east end. Replacing the ends requires both ends to be removed to at least where more severe damage was noted.
According to the inspection report, the culvert is not structurally compromised because the current deformation is 12.5 per cent, less than the limit of acceptable vertical deflection, which is 20 per cent.
The estimated cost for this option was $330,000 to $450,000, with staff doing all of the earthwork.
Option two called for the replacement of the entire culvert — 90 to 100 metres in length.
The estimated cost for this option was $850,000 to $1 million, with staff doing the earthwork.
Option three called for the full replacement of the steel culvert with a precast concrete culvert. This option would cost between $1.1 and $1.25 million and the earthwork would be completed by staff.
The cost of each option rose by $300,000 if a third-party contractor was hired.
