Calgary investigating wastewater leak in Bow River

The city is investigating how an unintentional wastewater leak into the Bow River occurred.

Calgary Mayor Jyoti Gondek notified the public on Saturday that testing results the city received on Friday from the Bow River near the Bonnybrook Wastewater Treatment Plant indicated waste had leaked into the river.

Crews identified a leak from a sewage pipe on the river's east bank, across from the Bonnybrook plant by the Ogden Road bridge. Gondek said on Saturday that the pipe responsible for the leak was found within three hours, valves to the pipe were closed and wastewater was diverted to two other pipes in the area.

After contacting Alberta Health Services and Alberta Environment and Protected Areas, Gondek reassured Calgarians that no water advisories are needed.

"Our drinking water is safe, risk to the public is low and we contained this issue within 3½ hours," Gondek said.

However, the city did advise people and their pets to avoid contact with the affected area of the river.

Crews will continue to monitor the river, testing water quality and investigating the source of the leak.

Doug Morgan, Calgary's general manager of operational services, said a potential problem was first noticed on March 19 when less wastewater than usual was found to be flowing to the plant.

His team began looking at potential causes like seasonal fluctuations, problems with the plant or external factors like leaks along its 5,000-kilometre wastewater system, but found nothing, while the wastewater flow continued to drop.

After test samples on Friday showed elevated E. coli levels in the river near Bonnybrook, a visual inspection of the Bow River's east bank led to his team finding the leaking pipe.

"It really was an issue with inflow into the water treatment plant, and there's lots of factors that can effect that," Morgan said.

"Generally, when we have a wastewater break, it's pretty apparent, 311 comes in quite quickly. This was something different, and we just tried to nail down all the variables as we worked through the process."

Morgan said downstream communities like Siksika Nation and Heritage Pointe were notified about the leak. He added he expects the water to recover quickly.

The city plans to provide further updates on the situation when it learns more about the leak.