Toronto ward six, Etobicoke-Lakeshore, had the most reports of basement flooding in the city, according to an analysis of data provided by the City of Toronto.
From January to June 30, 2015, residents reported 215 incidents of basement flooding. The eastern ward of Beaches-East York (ward 32) reported 209 calls and the western ward of York-South Weston (ward 11) had 199 reports. The ward with the lowest number of basement flooding reports was ward 39 Scarborough-Agincourt with 23 calls.
The city defines basement flooding in data documents as “cases of water or sewage entering a basement due to a blocked drain, sewer backing up, or surface flooding from storm events.”
A staffer from ward six councillor Mark Grimes’ office says the councillor wasn’t available to comment on this issue at press time. However, Randall Meier of Toronto Water says in an email “basement flooding is a complex issue,” and that residents should visit the city’s flooding site for more information.
There is a lot homeowners can do to prevent their basements from flooding even if they live in a flood-prone ward like Etobicoke-Lakeshore, says Dan Sandink of the Institute for Catastrophic Loss Reduction.
He says if you have a downspout connected to the sanitary sewer system, contact the city for information on how to remove it because it is now illegal.
“Fifty years ago it was common for home builders when they built new subdivisions to connect downspouts and foundation drains into municipal sanitary sewer systems,” he says. “So when you have [a] major rain fall event this can cause the system to become overloaded and cause sewer backup.”
The city has a special program to help subsidize the cost of the removal of these drains, he says.
Homeowners should also examine the grading of their properties to make sure water can drain away properly from foundation walls, he says.
“[Also] consider installing a backwater valve on your sanitary connection,” he adds. “If the sanitary sewer backs up, the valve closes and reduces [the] risk of getting flooded.”
Sandink says a survey conducted by the City of Saskatoon concluded that these valves were effective 85 per cent of the time in preventing sewer waste from backing up into basements.
While older neighbourhoods like Etobicoke-Lakeshore may face a bigger challenge when it comes to basement flooding, newer developments are being built to new standards that can better handle extreme rain events, says Rehana Rajabali of the Toronto Region Conservation Authority.
She says the key is to plan housing developments that drain away water in a more natural fashion, rather than over-engineering a plot of land that tries to fight the natural flow of water in an area.
“The more we can try to mimic those [natural cycles] within our urban areas, the less strain [there will be] on our urban infrastructure,” she says.
Rajabali says encouraging “smart development” of new neighbourhoods has an impact system wide – from local sewers to rivers.
“Not only does it help address the quantity of water that’s coming through but it improves the quality of storm water by the time it enters our rivers,” she says.
Still, even with new building standards and homeowners doing basic things like removing downspouts, flooding will still occur during extreme rain fall events due to climate change, she says
“The signs are pointing to more frequent and more intense storms. This is something we have to keep an eye on,” she says. “It’s the number one risk on my radar.”