Freeze-thaw cycle creates water-main havoc
As the temperatures shift, so do pipes in ground, causing major breakage and damage to roads
It’s that time of year again — the time of falling snowflakes, extra layers of sweaters and, of course, the water mains and roads of the city working together to bring ordinary life to a grinding, freezing halt.
Bill Shea, Director of Distribution & Collection in Toronto Water, is used to dealing with extra reports of water main breakages when the weather gets cold, since the winter months account for around 70 per cent of the annual reports. But with this year’s bout of early cold snaps and the ensuing thaws, the city is finding itself battling more problems than usual.
“This year, Jan. 1 till today, I think we’ve had 150 water main breaks,” Shea said. “Last year, during the same period, we had 50. So it’s three times (as much as usual) because of this cold weather.”
Twitter is beginning to flood with reports of water main breaks from citizens and official city sources alike, with people trapped on their streets by the bubbling breaks, and streetcars and buses being forced to detour around emergency repairs. Shea said it’s the ups and downs of the weather — not merely the cold itself — that are to blame.
“Yesterday, we had between 20 and 30 water main breaks because it got warm. It’s the transition, es- sentially. It gets cold and then it gets warm — that freeze-thaw cycle causes the ground to shift and the shifting ground breaks the water mains, and in particular our cast-iron water mains, which are more brittle than, say, plastic water mains.”
Concerns about pot holes on the roads are also rising amid the increase in water main breaks.
Cheryl San Juan, a city spokesperson in design and construction, said that although spring is usually when they see the most potholes, “it can happen at any time of the year, when we experience freeze/thaw conditions.
“Potholes are created when water penetrates the top layer of asphalt through cracks in the road. After the moisture freezes and expands, sections of the pavement are forced up. The weight of vehicles going over this section of road breaks the pavement and the asphalt is forced out.”
The average age of the pipes in the ground is 60 to 70 years old, Shea said, and around 30 per cent are still cast iron, which are more susceptible to breaks.
“Maybe 10 per cent of the infrastructure is over 100 years old. We’ve got water mains in the ground that are 120 years old.
“We’re spending $158 million this year in replacing and realigning water mains to try and mitigate some of that.”
That budget, a projection for 2018, only covers the planned replacement of pipes, and cannot account for emergency water-main breaks, which balloon the overall cost to the city.
“If we get1,500 water main breaks a year, we’re spending tens of millions of dollars to fix those water mains, so that’s above and beyond,” Shea said.
The annual number of water main breaks, which Shea averaged at 1,200-1,500, really depends upon the winter. 2016 and 2017 saw relatively low numbers at 1,120 and 1,009 respectively.
Shea said “2016 and ’17 were fairly mild (winters), so it was much less.” This doesn’t bode well for 2018 based on the weather so far. The number of water main breaks in 2015 — which had a winter that brought us wind chills of -40 C in February — soared to 1,803.
The amount of potholes plaguing the city’s roads also rises dramatically in harsher winters. Comparing 2017’s 199,032 and 2016’s 181,286 potholes to 2015’s 251,142 shows the stark difference. After the “polar vortex” of 2014’s winter, there were 363,198 potholes that year, and 1,786 water main breaks.
The total economic impact on the city is “very difficult to predict,” Shea said, especially since water main breaks also disrupt public transportation frequently.
“But if you look at everything in Toronto Water’s budget over the next 10n years, to put into infrastructure, it’s $2 billion.”
On average, it’s around eight hours for a crew to fix a single water main break, though they aim to do it within a four- to five-hour period. Around 15 or 20 crews are in the field at this time of year on any given day, but when even that is not enough, they have standing contracts with companies to assist them in fixing the water mains.
It’s a job that never ends. Shea said it’ll be “between 10 and 20 years before we’ve replaced everything. Of course, by that time, you’re going back and doing it all over again.”
As well as water main breaks, crews have been fielding increased reports of frozen services.
“We’ve gotten about 500 of those calls in the last two weeks about people not having water,” Shea said.
“So we go out and investigate it, and it turns out that 90 per cent of those have been in someone’s home, it’s not actually the pipe in the street. “
To protect pipes in your own home from freezing, Shea said, you can put heaters in basements that may be drafty, leave a few taps dripping during particularly cold nights, and insulate well around anything that is letting cold air come in.
“The best thing you can do for us if there is a (water main) break in your neighbourhood is be patient, No. 1. No. 2 is if you do have your vehicle on the road and it’s around a water main break, just move it. If you can, fantastic.”
As for potholes problem, San Juan said the main way residents can help is just by reporting them: “they can report online or by calling or emailing 311 or by using the 311 app available online. Crews will repair potholes within four days of them being reported.