Banff Spent $932,000 Rehabilitating These Sewer Pipes. Now The Liners Are Failing

Two backup sewer pipes beneath the Bow River need more work just three years after a $932,000 rehabilitation.

The Town of Banff says liners installed inside pipes in 2023 are collapsing when river levels are high, reducing how much wastewater can flow through them.

The pipes serve as a backup to Banff's main sewer system and currently work as intended when river levels are lower. 

The town is planning work for 2027 to address the problem.

"The flexible fiber-reinforced liner is collapsing during periods of high river level, and this means the flow in the pipe is reduced," the town told Bow Valley Insider.

What are the pipes used for?

The two emergency sewer pipes are located beneath the Bow River near the Thunder Medicine Pipe Bridge.

They aren't part of Banff's regular sewer route. Instead, they're a fallback system if there's an issue with the lift station or main sewer line that crosses the river.

The original pipes were installed before 1970 and were inherited from Parks Canada when the town incorporated in 1990.

In 2023, the town rehabilitated the contingency sewer system. The pipes were lined with a flexible fibre-reinforced high-density liner intended to extend their life expectancy by about 50 years, according to the town. 

The rehabilitation cost $932,000 and was funded entirely through the Banff’s Utility Reserve.

"No tax dollars were used," the town said. 

The issue was first noticed in 2024

The town first noticed something wasn't working as expected in May 2024.

"An increase of a flow rate at the Muskrat Street lift station was noted in May 2024, indicating the flow was not going into the emergency overflow pipes like it is supposed to," the town said. 

The issue was confirmed when it happened again in April 2025.

The liners installed during the 2023 rehabilitation now need to be replaced.

"The liners installed in 2023 are not working as intended and replacement is required to restore the pipes as a reliable emergency sanitary sewer conveyance,” the town said.

The backup still works at current river levels

The problem doesn't mean Banff's sewer system has stopped working.

The contingency pipes are also functioning as intended at current river levels.

The issue arises when river levels are high. That's when the flexible liners can collapse, reducing the amount of wastewater that can move through the pipes.

"Should the lift station located on the north side of the Thunder Medicine Pipe Bridge fail, the contingency pipes will not work during periods of high river flow," they shared.

"With the current river levels, the pipes are functioning, as intended."

According to the town, there is always some risk of wastewater reaching the water when a sewer pipe is installed in a riverbed. The work undertaken on the system is intended to minimize that risk as much as possible.

Town says there was no workmanship deficiency

Standard General was the contractor for the 2023 rehabilitation and is now working with the town to resolve the issue.

The town says it hasn't identified a problem with the contractor's workmanship.

"There was no deficiency with the workmanship of this contractor, the issue is with the flexible fiber-reinforced liner itself, and the failure condition was unforeseen at the time of installation," they said. 

A different liner is being considered

One option being considered is removing the existing liners and replacing them with rigid slip liners.

"We are in the planning stage and currently we are considering removal of previous infrastructure to allow installation of a rigid slip liner instead," the town told Bow Valley Insider.

Unlike the existing liners, the proposed rigid liners are designed to hold their shape without relying on internal pressure and withstand pressure from outside the pipe.

A final plan and construction schedule haven't been determined.

"We do not have a timeline at this point," the town said. 

Planning is still underway, including regulatory approvals with Parks Canada, Fisheries and Oceans Canada and Transport Canada and further assessment with the contractor.

Work is planned for 2027

The town posted a Canadian Navigable Waters Act notice on Sept. 16 outlining plans for work on the contingency sewer system in 2027.

The notice said repairs would likely require excavation at the riverbank and could potentially require work in the riverbed.

The town has since told Bow Valley Insider that work on the contingency pipes will be confined to the riverbank.

During the 2023 rehabilitation, equipment entered the Bow River to construct a barrier of rocks and stones downstream of the pipes to reduce erosion and the chance of the pipes becoming uncovered. 

The town said the work on the pipes themselves was done from the north and south shores, outside the river and riverbed.

The barrier was intended to reduce erosion and the chance of the pipes becoming uncovered.

The town doesn't expect the Thunder Medicine Pipe Bridge to close during the upcoming work.

It's not yet known whether nearby trail access will be restricted. That will depend on the final project scope and where construction equipment needs to be stationed.

Work is planned for 2027, but the town doesn't yet have a construction start or completion date.