The city released preliminary results of an investigation into the Bearspaw South water main failure Friday afternoon, suggesting a number of factors were to blame for the failure.

The aim of the investigation, supervised by Associated Engineering and Pure Technologies, was to better understand what led to the deterioration of the pipeline until it ruptured on June 5, 2024.

Investigators isolated three possible factors in their Friday statement:

• Microcracking of the outer layer of protective mortar of the pipe;
• High chloride levels in the soil in various locations; And
• Broken wires due to corrosion and hydrogen embrittlement.

They concluded that no single factor led to the main failure in June.

“The Bearspaw South Mainline is a critical piece of infrastructure and is responding well to the rehabilitation work that was completed between June and November and is now stabilized,” said Michael Thompson, general manager of water services. infrastructure of the city of Calgary.

“Thanks to our acoustic monitoring, we only recorded two wire breaks on the main pipe between October and November. In July and August, there were 23 carabiners.

Preliminary review of the pipeline design and operation confirmed that the original design complied with the guidelines at the time.

The pipeline operations were found to largely meet the pipeline design parameters.

What’s next

The final report will be presented to the city’s infrastructure and planning committee on December 11.

Construction of two other sections of pipeline, including one along Parkdale Boulevard. NW between 26 Street and 27 Street NW and the other at the Memorial Drive off-ramp on northbound Crowchild Trail are both nearing completion.