Waste from Bonnybrook Wastewater Treatment Plant leaked into Bow River according to City’s testing results from Thursday.
The city said drinking water is safe, while the risk to public caused by the leaked pipe is low.
The leak was identified Friday on the east bank of the river across from the the Bonnybrook Wastewater Treatment Plant by the Ogden Road bridge.
The city’s water management team identified and shut down the leaking pipe within 3.5 hours.
Crews were able to identify the pipe that was the source of the leak and turn off valves leading to it before diverting wastewater flows to two other pipes in the area.
Alberta Environment and Protected Areas and Alberta Health Services and communities downstream were immediately notified.
Mayor Jyoti Gondek was happy the crews acted early, but says communications could have been better.
“The flow of information was disappointing, but I called for a briefing at 8 p.m. after I was able to leave an important community event. During the briefing, it became quite apparent to me that the most urgent thing to do was to tell Calgarians,” the mayor said.
City crews contained a wastewater leak in the Bow River on Friday, March 28. Drinking water is safe and ongoing monitoring and water quality testing are in place.
— City of Calgary (@cityofcalgary) March 29, 2025
For more information: https://t.co/zueHWtlkC5
The potential issue was first noticed back on March 19th, when crews noticed Bonnybrook Plant wastewater levels were lower than normal.
“We began looking at potential causes for those lower levels to see if they could be explained by normal seasonal variations. Issues with our plant or other factors,” said Doug Morgan, general manager of operational services.
During the investigation, the crews noticed levels continued to drop but did not notice anything wrong with the plant or “large industrial customers that have changed their process.”
‘A visible leak’
On Thursday a visual inspection of the riverbank near the water treatment plant was conducted which still displayed no issues. It also took testing samples.
“On Friday morning, we received test results on the river water that showed elevated E.coli levels in the river near the Bonnybrook plant,” said Morgan. “We then did another visual inspection of the river and saw a visible leak in the river at approximately 11 a.m.”
The pipe would be shut down with the wastewater rerouted. The city is currently conducting a full assessment to determine the last inspection date for the pipes in the area.
