The underground repair work on the Bearspaw south feeder main was completed on Tuesday, and city officials say step one of the restoration process will begin on Wednesday, meaning there are still several days to go until Calgary’s water supply is fully restored.
Michael Thompson, the City of Calgary’s general manager of infrastructure services, says the restoration could be complete ahead of the city’s previously announced three to five-week timeline.
“The new, best-case scenario for easing indoor water saving measures could be July 1. However, this is if all steps go perfectly,” said Thompson on Wednesday afternoon.
“And as mentioned previously, we’re still managing a significant amount of risk.”
On Wednesday afternoon, Calgary Emergency Management Agency (CEMA) chief Sue Henry says the City of Calgary’s Canada Day-related fireworks will go on as planned.
“Under the current fire ban, fireworks are allowed on a case-by-case basis,” she said.
Regular water flow still ‘days away’
The Bearspaw south feeder main — a large pipe responsible for carrying treated water from the Bearspaw Water Treatment Plant to the rest of the city — ruptured on June 5.
Its rupture led to outdoor water restrictions, with the city also urging residents and businesses to cut back on their own use to maintain enough water for emergencies, such as fighting fires and use in hospitals.
On Tuesday afternoon, city officials said narrowing down an exact date for when all water-related restrictions will be lifted is difficult, and even though the underground repair work is complete, the next stage of bringing the city’s water supply back to full capacity is just getting started.
For now, the city is still “days away from regular water flow,” according to Calgary Mayor Jyoti Gondek. In the meantime, the water network is still relying on the smaller, older Glenmore Treatment Plant to supply the Calgary area with the majority of its water.
Crews began the cleanup work surrounding the Bearspaw south feeder main on Tuesday, including backfilling the excavation sites. The mayor says repaving certain sections of torn-up road will begin today.
City of Calgary director of capital priorities and investment, Francois Bouchart, says that because the system has “undergone a major shock,” crews need to move carefully.
“We have four steps: filling the feeder main, flushing the feeder main, testing the water and then stabilizing the system,” said Bouchart during the Tuesday afternoon update.
“This is delicate work. Each one of these steps carries risk, and it’s likely that we could have some setbacks along the way.”
On Tuesday, Thompson said that during the filling stage, the pipe will undergo an increase in pressure,” which increases the risk of stress and potential further breaks.”
In order to help manage the risk of additional ruptures, crews will be using acoustic monitors to listen for wire breaks, as well as sensors to detect pressure spikes.
Updated timeline
On Tuesday afternoon, Bouchart detailed what the rest of the water-restoration process will look like.
Filling the feeder main is the first step in the city’s water restoration process. Bouchart says it will take roughly 14 million litres of water to refill the 4.5-kilometre section of pipe, and this step should take about a day or two.
The next step will involve flushing the pipe with de-chlorinated water and draining it into the Elbow River, and this step should take about one day. Bouchart said this step is a necessary part of making sure this water is safe to drink.
After flushing the pipe, testing the water quality is the next step — Bouchart says Calgary Gallery microbiology sampling takes about 18 to 20 hours. Should all the tests come back clear, restoring the water can then move to the next step.
However, if the tests show the water isn’t safe to consume, the pipe will need to be flushed once again, which he says could add another 24 hours to the process.
Once the water quality meets regulatory standards, water from the feeder main can once again flow throughout the rest of the system. Bouchart says this step has the “highest level of risk” due to the pressure changes, so stabilizing the system will then take another three to five days.
City officials provide update on major water main break affecting Calgary’s water supply.
Starting on Friday, crews will begin flushing the pipe, the second step of the restoration plan.
In response to the flushing process, the north Edworthy Park parking lot will be closed on Thursday night, and adjacent pathways will be temporarily detoured. The south parking lot will remain open.
“This work will also have some impact on our river users, as it involves releasing large volumes of de-chlorinated water into the Bow River near Edworthy Park,” said Henry.
“The river will remain safe for floating and boating,” she added, but river users are asked to stay off of the north shoreline of Edworthy Park over the upcoming long weekend.
Calgary remains under a state of local emergency, and the Stage 4 outdoor water restrictions and citywide fire ban remain in effect.
Gondek stressed that residents of Calgary — and the surrounding areas that rely on its supply — must continue to conserve water.
She says water use for the Calgary area reached 471 million litres of water on Tuesday, which she says accounts for 98 per cent of the 480 million-litre acceptable usage threshold.
“Any more and it puts us potentially at risk for life-saving measures like people in hospitals or firefighting efforts.”
Municipal infrastructure in other Canadian cities
Also during her morning briefing, the mayor said the city’s planned third-party review will be an essential part of assuring that Calgary’s water infrastructure is safe and strong for years to come.
“The independent review will also help cities learn how to avoid what happened in Calgary,” said Gondek.
The mayor also addressed a major water main break in Quebec City that triggered water restrictions for a third of its residents, effective Wednesday morning. Gondek says she’ll reach out to Mayor Bruno Marchand to offer any “support or expertise” the city can provide.