Waterlogged

Waterlogged

Lessons learned from hurricane Hazel saw Toronto holding its own, despite a record-breaking 126 mm of rain.

It pays to think things through. Or, put differently, there’s a price for failing to do so. For the driver who gambled Monday on the slim chance his Ferrari could plow through a small lake on Toronto’s Lower Simcoe Street, it could reach $250,000—assuming the car’s 4.3-litre, V8 engine is shot and its Italian leather interior beyond salvation. No doubt he and his luckless insurer were toting up those costs while the sleek, silver machine sat window-deep beneath a railway underpass just east of the CN Tower.

“Ferrari Man” became a target of social-media schadenfreude during the greatest day of rainfall Toronto has known. But he was hardly alone in the dubious-judgment department. When waters from the Don River surrounded a GO commuter train, one passenger plunged into the water, laptop in hand, and had to be rescued while clinging to a tree. Another man was photographed swimming in the reservoir beneath a King Street underpass, evidently forgetting that what goes into a city’s sewer comes out when it overflows.

In general, though, Torontonians kept their heads, and when a record 126 mm of rain had finished falling, they could be thankful for the foresight of past urban planners. The 1950s-era storm-sewer system held up amid the flash floods, and by morning, the city’s rhythms had returned—albeit at a slightly slower tempo. Buses were running and so was most of the subway. Power was out in the west end, and basements had taken on water. Yet the damage was contained mostly to low-lying stretches of freeways, streets and parks.

So compared to the recent floods of southern Alberta, it was a cakewalk, and that’s partly an outcome of the last such deluge to hit Canada’s largest city. On Oct. 15, 1954, hurricane Hazel made her way inland, carrying 121 mm of rain that turned the Humber River on Toronto’s west flank into a torrent that swept away entire neighbourhoods. Eighty-one people drowned, and the legacy of that trauma was a lasting distrust of the seemingly placid rivers and creeks that criss-cross the city. A regional conservation authority was formed, and it quickly declared ravine bottoms off-limits to development. “Hurricane Hazel still sits in the memory of a lot of people,” says Stephen Bocking, a Trent University professor who has studied the building of Toronto during the postwar era. “We learn slowly, but we do learn.”

More such lessons await. At a recent symposium at Ryerson University, an expert from the city’s environment and energy office noted the rising frequency of extreme weather events across Canada, citing climate models pointing to a future of much hotter, much wetter summers in southern Ontario. Within three decades, the projections suggest, the average month of July will bring 80 per cent more precipitation than it does today, and if it comes in bursts like Monday’s storm, the work done 60 years ago won’t be enough. On the Don River, water levels leapt some 3.1 metres within three hours—a boost roughly commensurate with the surge on the Bow River that caused flooding in Calgary. It was enough to submerge a goodly stretch of the nearby Don Valley Parkway.

The splash of reality has lent urgency to infrastructure renewal plans, including a $1-billion, 25-year update of storm- and waste-water systems. And while traditional remedies have been augmented with new ways to reduce surface runoff—green roofs, permeable paving surfaces, more forest cover—it will all take time to build. In the meantime, central Canada’s tropical summer continues, with its alternating beat of soupy heat and menacing storms.

Maclean's July 22, 2013