TOUGH START TO THE DAY
Official says unseasonably warm fall, new infrastructure among the reasons
City of Saskatoon workers attend to a water-main break that flooded McKercher Drive near 8th Street East on Friday morning. A city official says the number of ruptures so far this year is well below average due to a warm autumn and new infrastructure.
Broken water mains are a fact of life in Saskatchewan. City of Saskatoon crews spent Friday morning working to repair a couple of burst pipes, including one that flooded part of a busy intersection on the east side.
According to the City of Saskatoon, however, the number of ruptures identified and repaired so far this year is well below average, a fact its director of water and waste stream attributes in part to a warm autumn.
Unseasonably warm temperatures late last year slowed the penetration of frost into the ground, where it can expand enough to crack the roughly 3,000 kilometres of water and sewer pipe running under the city, Russ Munro said.
“What can happen is you’ll get uneven frost expansion or heaving, and one piece of the pipe isn’t moving — and it’s embedded, of course, in the earth — and the other piece is, and that’s where we’ll get the failure,” he said.
“It’s one of those things with Mother Nature — if the earth is going to move, it’s going to move, and it doesn’t care if there’s a pipe there,” Munro added, noting that while pipe design and installation have improved, there is only so much that can be done.
Another factor contributing to the lower number of breaks is likely investment in new infrastructure, Munro said.
The city, in its preliminary 2019 budget, committed $2.9 million to water-main rehabilitation and replacement.
City data shows 18 water-main breaks have been recorded so far this year, an average of about three per week. By comparison, 48 pipeline breaks, or about eight per week, were reported over the same period last year.
A combination of little snow, which acts as an insulator, and bitter temperatures pushed the number of breaks last year above historical averages for the same period — 40 over the last 24 years, 34 over the last five and 35 over the last three.
“We are preparing and anticipating that there could be more breaks as the winter progresses, now that we’re into that typical -40 kind of Saskatchewan winter,” Munro said, referring to the polar vortex that sent mercury plummeting this week.
The city’s water and waste water system is a patchwork of old and new pipes. The oldest are made from thick cast iron installed around the turn of the last century. Munro said they tend to be more durable than thinner postwar castiron pipes.
More recently, municipalities like Saskatoon have turned to pipes made from polyvinyl chloride, commonly known as PVC. While no pipe can stand up to major ground movement, Munro said the newer pipes are more durable because they can flex.
According to the city, the average cost for a complete water-main repair is between $14,000 and $15,000, though Munro noted that every break is unique in terms of labour, equipment and materials.
We are preparing and anticipating that there could be more breaks as the winter progresses.