from the Globe and Mail
January 29, 2005
It's a cold winter afternoon on Duffield Road, a residential side street in mid-Etobicoke, and the crew from the Bering Street city works yard has a wet, miserable job in front of them. The sidewalk and street are slick with ice and dirty water that has bubbled to the surface from a broken water main. They'll have to shut off the water, dig down to the break, disinfect the exposed area and secure a sleeve over the fracture -- all before suppertime.
Such work usually goes unnoticed, but last Sunday the city got a jolting reminder of what can happen if a main snaps in the wrong place when a break under Bay Street flooded an electric transformer station, shutting down power to the city centre and leaving thousands of downtown dwellers without heat on one of the coldest days of the year.
While such havoc is uncommon, water-main breaks in the city are not. according to a recent provincial analysis, Toronto has the highest rate of breakage in Ontario, about 30 a year for each 100 kilometres of pipe -- twice the provincial average. For works crews, that means repairing as many as 1,500 breaks a year. For homeowners, it means rising prices for water.
City council increased water rates by 9 per cent in both 2002 and 2003, in part to raise the money needed to replace and refurbish the deteriorating network of pipes. Last November, it approved an additional 6-per-cent hike and a further increase of 7 per cent in both 2006 and 2007. Under the city's current plan, the average household will be paying an estimated $427 a year for water in 2007, compared with $373 this year.
The broken water line on Duffield Road, where houses were built in the 1960s, is only about 40 years old, but 8 to 9 per cent of the city's 5,000 kilometres of water mains were put in more than a century ago.
One of the ironies is that the newer mains -- mostly installed during the postwar building boom in parts of the city such as Etobicoke, North York and Scarborough -- are giving way at an earlier age than their elderly cousins in the older areas. Mike Price, general manager of Toronto Water, surprised the press when he said the main that broke under Bay Street was installed only in 1973.
Joe Cirillo, the city works manager in charge of the Bering yard, says the explanation for the difference in breakage in different parts of the city is simple. Pipes laid before the Second World -- made to last by British ironmongers -- were thicker-walled than the postwar ones, and they take much longer to corrode to the point where they can't take a Canadian winter.
But all pipes corrode eventually, both from the inside and the outside. The corrosion speeds up if the soil around the pipe is acidic or there is a low-voltage electrical current in the soil, as there sometimes is in an area where wires are buried.
For a break to occur, the pipe has usually corroded to the point where it can no longer take the stresses placed on it. While vibration, such as from traffic that passes overhead, can break a pipe, most of the breaks in Toronto are the result of cold weather.
an iron pipe, which is rigid and has no flex in it, gets even more brittle as both the ground around it and the water flowing through it get cold. and when the soil above it freezes and expands, it can put enough pressure on the pipe to snap it.
The Bering avenue crew usually fixes three pipes a day, but with several days of temperatures in the minus double digits, they had 28 breaks on the assignment board by Tuesday.
To tackle the problem, the city is tapping increased revenues from higher water rates. It plans to increase the number of kilometres of water mains it replaces with more durable PVC pipes from 22 in 2004 to 80 by 2009, and the number of kilometres it rehabilitates with concrete lining and protection from electric currents from 120 in 2004 to 176 in 2009. The plan is to more than double the total capital spending on the city's water and sewage system, from $252-million last year to about $540-million a year by 2008.
Councillor Jane Pitfield, chairwoman of the city council's works committee, says residents won't mind water-rate increases, especially if they know it is going to go to the infrastructure. "If you want to pay less, you use less," she says. "If we make water more expensive, then people will conserve it, and not use it wastefully."
It's a dirty job
To fix a broken main, the crew turns the water on the block almost all the way off, but leaves a trickle flowing to stop muddy water from back-flowing and carrying germs into the main.
Then the crew excavates a hole around the break, using a backhoe to crack through the frozen soil under the road pavement. Muddy water is pumped out, and after a trench box -- the sides of which prevent the possibility of a cave-in -- is hoisted into the hole, the worker who will repair the break climbs down a ladder into the muck.
after any corroded rusty material around the break is cleaned up, the pipe is sprayed with a chlorine compound that acts as a disinfectant, and the main is fixed by clamping a stainless steel sleeve around the break with huge bolts.
"That is a permanent repair," says Joe Cirillo, a city works manager.
Since the Walkerton contaminated-water deaths, one of the workers on the crew must be a certified technician to ensure all Ministry of Environment procedures are properly followed. That includes testing a sample of water for an elevated level of chlorine -- the sign that proper disinfection has been done.
all that remains to be done is call a road contractor, who will fill the excavation with a quick-setting compound of gravel and cement that will be paved over when warm weather comes.
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