Engineering review of Calgary’s 2024 feeder main break finds no concerns with city practices

Work to repair a major water main in Calgary on Friday, June 7, 2024. (THE CANADIAN PRESS/Jeff McIntosh) (Jeff McIntosh/The Canadian Press)

An independent review of Calgary’s critical feeder main break last year found the city’s engineering practices were sound.

The Association of Professional Engineers and Geoscientists of Alberta (APEGA) launched a review following the rupture of the Bearspaw South water main in June 2024.

The APEGA said the City of Calgary had “sound engineering oversight and the appropriate risk-based management in place” in relation to the water main.

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It also found the city was in compliance with engineering bylaws and practice standards.

“No indications of unskilled practice or unprofessional conduct were found during the practice review,” the APEGA said in a Wednesday news release.

The association said the failure of the water main, a prestressed concrete cylinder pipe (PCCP), is consistent with other failures of similar pipes around North America.

“At the time of installation, in 1974, the feeder main was reportedly expected to have a 100-year service life,” the AEPGA said.

“However, PCCP manufacturing standards were relaxed from the late 1960s to the early 1970s by the American Water Works Association, resulting in a high rate of premature failures, and standards have since been strengthened.”

The report added that preventing a pipe rupture cannot be assured, even with monitoring and predictive technologies in place.

Calgary Mayor Jyoti Gondek thanked the APEGA for their independent review and credited city staff and engineers for their work during the break, in a statement Wednesday.

“The city has already implemented improved monitoring and is focused on proactive maintenance of our most vulnerable infrastructure,” Gondek said.

“But this event is also a clear reminder that sustained investment in our water systems is not optional. It’s essential to public safety, economic stability, and Calgary’s future growth.”

The City of Calgary finalized its own report on the June 5, 2024, water main break in December 2024.

The report, prepared by Associated Engineering, said design and operations of the feeder main did not contribute to its failure, but “several failure mechanisms” and “soil conditions” did.

The city was aiming to release its plan to strengthen Calgary’s water infrastructure by the middle of 2025. The mayor said she will be providing a comprehensive update on the city’s response, improvements and future infrastructure strategy.

The break flooded a section of northwest Calgary, leading to a local state of emergency.

Water restrictions were put into effect for all Calgarians, including residents in surrounding communities that relied on water produced at the Bearspaw treatment plant.

The restrictions were lifted in the fall and all repairs to the feeder main were wrapped up in late 2024.

With files from Michael Franklin and Alesia Fieldberg