Repairs on Calgary's broken feeder main are now complete, but water service not yet restored
Several critical steps still needed before city supply restored to normal
Repair work on the five additional "hot spots" of the Bearspaw south feeder main is now complete, but the full restoration of Calgary's water supply is still days away.
Mayor Jyoti Gondek shared the news during her Tuesday afternoon update on the developments of the water feeder main, saying the underground repair work on the pipe has now been completed and the city is hopefully on track to have water service restored before the Calgary Stampede.
"That date is still a good guideline," said Gondek when asked about the city's previously stated July 5 completion timeline.
"I think it's important to remember that the date that was offered when we first entered into the stage of doing the hot-spot repair ... What we've heard from the team today is that it's possible, if things go according to plan, that we might see an earlier timeline."
But city officials say narrowing down an exact date for all water-related restrictions to be lifted is difficult.
"We have heard some concerns over the last few days about why we're allowing Stampede to move forward given the state of restrictions here," said Michael Thompson, the City of Calgary's general manager of infrastructure services.
"Many businesses and industries rely on the Stampede as a critical event for survival and employment. As we've said before, we are aiming for the earliest possible restoration of service in our original timeline of three to five weeks, which means we could be getting back into service in time for the start of Stampede."
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.
"We're still days away from regular water flow," Gondek said during Tuesday morning's update. "We're still relying on the smaller facility at Glenmore to provide water throughout the city."
Plus, backfilling the pipe repair sites and repaving the road in areas along 16th Avenue N.W. will begin on Tuesday and continue into Wednesday, so traffic disruptions will remain for some time.
Restoring water is 'delicate work,' more ruptures possible
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.
"This is delicate work. Each one of these steps carries risk, and it's likely that we could have some setbacks along the way."
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 says 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 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.
Thompson says 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 additional wire breaks, as well as sensors to detect pressure spikes.
The Bearspaw south feeder main, a major pipe transporting roughly 60 per cent of the city's treated water supply, 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.
During Tuesday's afternoon briefing, officials continued to urge residents to curb their usage. They say the demand for treated water has been rising once again, and the warm weather is forecasted to stick around.
On Monday, water use for the Calgary area was 476 million litres, which is very close to the 480 million-litre threshold, said Gondek.
What's more, officials say that over a half million litres of water have been picked up at the city's various non-potable river stations.
These river water locations allow Calgarians to access untreated water — intended for residential gardens and for larger industrial uses — and were part of an emergency plan to get water to commercial users amid the ongoing water supply crisis.
On Wednesday, the city is adding a seventh location to retrieve river water, at the Bankside Day Use Area in Fish Creek Park, for access to both commercial and residential uses.
Calgary remains under a state of local emergency, and the Stage 4 outdoor water restrictions and citywide fire ban remain in effect.
To date, the city's 311 service has received nearly 9,500 calls related to water use and the fire ban. Bylaw officers have issued 17 tickets for water misuse, and five tickets for violating the fire ban.
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With files from Omar Sherif