July 15, 2020 by Adam Malik
Old infrastructure and combined sewer systems mean that severe thunderstorms like the one seen last week will continue to leave basements flooded for years to come, leaving insurers and claims professionals busy, according to an industry expert.
“When you get a storm like this hitting an older part of town, that’s when you start getting into trouble because the drainage infrastructure and the stormwater management infrastructure tends to be a little bit older,” observed Glenn McGillivray, managing director at the Institute for Catastrophic Loss Reduction (ICLR).
Adding to the complexity of the issue is that much of Toronto’s sewer system is combined — meaning stormwater and wastewater are running through the same pipe. “So there’s very little extra capacity for rain and that’s when you see rainwater shooting out through manhole covers 20 feet in the air, as we saw [last week]. The system can’t handle that amount of rain,” McGillivray told Canadian Underwriter the day after the July 8 storm.
“And in terms of the sanitary sewer system, it’s not designed for any rain at all — it’s designed for sanitation.”
Last week’s thunderstorm hit mainly in the city’s west-end neighbourhoods of The Junction and High Park, as well as parts of Etobicoke and North York. The Toronto and Region Conservation Authority reported 65 mm of rain fell in about 35 minutes — the typical monthly average is about 80 mm.
“Certainly, Toronto’s been getting whacked quite often with these events. It’s almost becoming a nuisance storm-type of situation,” McGillivray said.
These kinds of quick-hitting storms overwhelm infrastructure and create claims. “These systems get overloaded very quickly, especially with the amount of rain we had in a very short period of time,” he added. “And that’s really the issue. If you get 100 mm of rain over the course of a whole day — a slow-soaking event — the system can usually catch up.”
A popular belief is that because the infrastructure was designed in the 1950s and 1960s, the system can’t handle the storms seen today. That’s not an accurate assessment of the situation, McGillivray said. “They were never designed to handle extremes like this. If you put a system underground to handle a storm like [Wednesday’s], that’s a pretty costly endeavour. We have to get over this idea that the system was built for storms of yesteryear. They were never built for extremes. They get overwhelmed and basements flood.”
He did commend Toronto for its efforts to help its residents guard against basement flooding. But plenty of education is still required, he said.
“It’s a tall order. It’s a big city, and they have a lot of places that are at risk. They’re triaging and working on them as they can. So that’s going to take some time. But it’s really critical homeowners take measures to prevent damage from their home,” McGillivray said.
ICLR has tips on its website to help owners. Such advice has also been a focal point for the Intact Centre of Climate Adaptation. Guidance ranges from simpler advice like not leaving important items in your basement — especially on the floor — to installing backwater valves and sump pumps.
“What we often see is people will point a finger at the city and blame the city. [But] there are measures people need to take themselves,” McGillvray noted.
And the insurance industry is right at the top of the list of those who can help. McGillivray referenced a survey his organization did a number of years ago that asked from where people wanted to get information about disaster risk reduction.
“And the Number 1 source was that they wanted it from their insurance provider,” he said.
Feature image: Nuno Carvalho surveys the flooding on Cordella Avenue after a severe thunderstorm caused localized flooding in Toronto on Wednesday, July 8, 2020. THE CANADIAN PRESS/Carlos Osorio