Water main break repairs underway as restrictions remain

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Calgary’s feeder water main repairs hit a crucial milestone Wednesday as the new steel pipe arrived, allowing crews to begin installation.

City officials say the pipe is expected to be installed by the end of Thursday; however, the pipe will then need to be flushed and tested, taking at least another five days.

It means Calgary’s water woes will continue until at least the middle of next week — nearly two weeks after the break occurred — when the city said they will know more about the timeline for relaxing restrictions currently in place.

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The water main ruptured June 5 in Montgomery, which reduced the city’s water supply and led the city to implement Stage 4 water restrictions and a citywide fire ban.

“This feeder main breaking has put us in a water gridlock — we cannot get 60 per cent of the water that we typically flow through this pipe out into our various communities,” Mayor Jyoti Gondek said Wednesday.

The 23.5-foot new steel pipe was disinfected Wednesday morning while crews were working on welding repairs for some of the access hatches along the pipe, according to water services director Nancy Mackay.

“The big job now for our team is to get that pipe into place, and there’s a large metal ring that will go around the existing (pipe) connecting it on both ends,” said Mackay.

Mackay expected welding to be underway Wednesday evening.

Information about the inside of the pipe is still being gathered by robots as repairs continue, and as of Wednesday afternoon inspection has been completed on 1.8 kilometres of the pipe.

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“Once the welding of the pipe is completed, we’ll continue to apply a protective coating on the pipe — and take some measures to prevent corrosion,” said Mackay. “We’re working, again, 24/7 on all those steps I just described so that we can get that repair done.”

When repairs are complete, crews will still have to remove all of the equipment and fill in the hole before 16th Avenue can reopen to traffic.

“This has been a huge (inconvenience) for folks, I absolutely appreciate that,” she said.

‘No indication’ of stress before the burst

The “catastrophic failure” of the main doesn’t evolve gradually, said Francois Bouchart with the city’s water resources department.

“If you think of a metal pipe and it had developed a crack, then the crack over time was slowly opened up, and as a result what you’d have is you’d start seeing a change in the performance of the pipe,” Bouchart said Wednesday. “You might be able to react.”

In this case, metal wires within the pipe “snapped,” leaving no structural integrity and allowing water to gush out in one big event, he said.

It is not clear when the last visual inspection was conducted on the pipe, which was approximately 49 years into its 100-year lifespan.

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Bouchart highlighted that although visual inspections can provide condition information, acoustic monitoring (which they have in place) can also tell whether wires are snapping.

“There was no indication that the section of pipe was being stressed,” said Bouchart.

“Our acoustic monitoring didn’t pick up wire snaps that would indicate that we were leading toward a catastrophic failure.”

Gondek said, “There’s regular modelling, as we have heard, and there’s no indication that this was going to happen. All questions will be answered in due time; right now, we just have to get our water supply up and running.”

The event as a whole has “definitely” reinforced the need for redundancy of the pipe, Bouchart said.

“We have been already many years in the planning of the redundancy components that are needed in the medium term,” he said.

Bouchart mentioned a north Calgary feeder main and Glenmore Water Treatment plan project, but didn’t provide more detail.

“There are many other ways that we create redundancy in the system.”

Water conservation efforts continue

One Calgarian uses about 173 litres of water per day on average, or about the equivalent of two full bathtubs. Usually this time of year, Calgary consumes about 580 million litres of water per day.

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On Tuesday, Calgary came in at the consumption threshold of 480 million litres of water used.

The city used 440 million litres on Saturday, 457 million on Sunday and 472 on Monday.

“While we are staying under the threshold that is critical to ensure that we have enough water for all of us, this gradual increase is certainly becoming a concern,” said Gondek.

A boil-water advisory that was in place for Bowness was lifted Monday, after the city diverted water and Alberta Health Services deemed it safe to drink.

Calgary Emergency Management Agency Chief Sue Henry said there have been 4,101 calls to 311 specific to the main break.

Using an “education first” approach, bylaw officers have issued 306 written warnings, 368 verbal warnings and one ticket.

swilhelm@postmedia.com

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