The City of Terrace is set to spend more than $1 million to repair a sewage treatment plant outfall pipe that was damaged during flooding in 2021.
Work done by consultants McElhanney found that a 30 metre section of pipe lost its armouring of concrete blankets during the high-water event, exposing it to the river and putting it at risk of even more damage should another high-water event take place.
In order to protect the pipe, the city needs to install pre-cast concrete blocks over the exposed area at a total cost of $1,224,491. That figure includes the construction cost, engineering, environmental monitoring and construction supervision, plus a 10 per cent contingency.
The funds will be drawn from the Northern Capital Planning Grant Reserve. The city is also in the process of applying for provincial disaster relief funding, which if successful would cover 80 per cent of the project cost.
“We have built in some design features into the new armoury that will enhance it over the existing armoury,” said Jonathan Lambert, director of engineering and public works.
“We can’t reasonably excavate and replace that original design and so we’ve moved to these pre-cast concrete blocks that are 14,000 pounds apiece … the sheer mass of them will resist the hydraulic forces of the river.”
Compared to the old concrete blankets, the new blocks have a lower coefficient of friction, which will allow water to flow easier and deflect passing logs and debris.
Repairs have been approved by the federal Department of Fisheries and Oceans and the provincial environment ministry. The city has notified the Kitsumkalum, Kitselas and Metlakatla first nations of the project.
According to the city, time is a factor in getting the repairs completed to avoid further damage and increased costs during the spring thaw.
Terrace received over $8 million from the province in 2019, and an additional $6.5 million in 2020 in the form of the Northern Capital and Planning Grant. Including the pipe repairs, the city has a projected $4,595,144 remaining from that fund.