Crews work to repair a major water main break and five other weak spots in Calgary on June 22.Jeff McIntosh/The Canadian Press
Calgary’s water conservation efforts are flagging, with Monday’s consumption hitting the highest point in 10 days – prompting the mayor to plead with residents and businesses to scrimp a bit more to keep the city safe.
Alberta’s largest city and the surrounding communities that depend on it for potable water consumed 476 million litres on Monday, Mayor Jyoti Gondek said the day after. This is down 11 per cent compared with the day’s five-year average of 536 million litres, according to the city’s data, but well below Calgary’s conservation target of 25 per cent.
The city and its neighbours have been under a combination of mandatory and voluntary water restrictions for most of the month, after the Bearspaw South Feedermain ruptured June 5. Officials previously said water consumption must stay below 480 million litres per day in order to maintain a sufficient reserve of water for fighting fires.
“If this is a one-day blip, I might not be so concerned,” Ms. Gondek said Tuesday. “But this is, again, the trend of creeping upwards in our water usage – and it is not a trend any of us want to see.”
Calgary and area reduced water use by 20 per cent compared with typical consumption over the 20 days since crews discovered the crumbled pipeline, the mayor said.
“We need to be down a little bit more to ensure that we have water stored up in case of any emergencies.”
The Bearspaw South Feedermain connects to the Bearspaw Water Treatment Plant and supplies potable water to roughly 60 per cent of Calgary and its customers. With the line out of service, the city is dependent on the older Glenmore Water Treatment Plant for safe, clean water.
On June 8, Calgary said repairs on the feedermain would take five to seven days, at best. But a robot, sent down the busted pipe to collect data, indicated five more spots were at risk of catastrophic failure if not urgently fixed.
In turn, Ms. Gondek on June 14 said the repairs – and water restrictions – could last another three to five weeks. On June 19, officials said the process could be wrapped up by July 5, which coincides with the first day of the Calgary Stampede.
On Tuesday morning, Ms. Gondek hinted the city may be on the verge of tightening the timeline again. However, at the city’s afternoon update, the mayor and other officials stressed that crews could discover further problems now that the repairs are complete.
Michael Thompson, the city’s general manager of infrastructure services, said Calgary will move slowly as it fills and flushes the line, tests the water quality and then stabilizes the system.
“Our concern is that something will break as we begin to bring this pipe back into service,” Mr. Thompson said.
“If things go according to schedule, we could be done earlier than expected, but there’s still significant amount of risk on this phase.”
The June 5 rupture caused the pipe to quickly lose pressure, which may have spurred other undiscovered breaks or weak points. Filling and flushing the line, along with replenishing the city’s underground reservoirs, will bring more pressure changes, which could reveal further problems, he said.
The troublesome feedermain is a prestressed concrete cylinder pipe, or PCCP, which was installed in 1975. PCCP, especially those constructed in the 1970s, are susceptible to catastrophic breaks. Calgary’s potable water infrastructure network contains 187 kilometres of the PCCP, and 48 per cent of this type of pipe was installed prior to 1979, according to the city.
While Calgary is flirting with hitting its water use threshold, officials managing the crunch have benefited from cooler weather this June.
During the heat dome in 2021, Calgary’s water use spiked to 820 million litres on June 28, when the temperature at the airport climbed to 34.6 C. The five-year average for that day is 519 million litres, according to city data.
Editor’s note: A previous version of this article incorrectly stated that Calgary officials said on June 21 that repairs and water restrictions could last another three to five weeks. That statement was made on June 19. The article was updated on July 2 and July 3, 2024, to incorporate corrections.