TORONTO – An overnight storm flooded a portion of the Don Valley Parkway (DVP) on Wednesday, and while it may be surprising to some – it has happened before and is likely to happen again.
Because the DVP is built in a valley beside the Don River, more water is likely to accumulate in the area, said Michael Heralall from the Toronto Region Conservation Authority.
Heralall explained that the way Toronto developed around the Don River and modified the natural state of the river in the process affected how the land dealt with excess rainwater.
“There’s less room for the water to flow,” Heralall said.
The development has also hampered the efforts of the land to deal with excess water, causing more to go into the river and making it more prone to flooding than it would be in its natural state, he said.
In 2005, 175 millimetres of water fell in one day, leaving cars stranded on the parkway and nearby Bayview Avenue.
In 2000, a similar flood forced emergency crews and trucks to pull cars from the flooded waters.
The main artery of the expressway took shape approximately 50 years ago when the city had different standards for flood protection.
And those standards may not have been accepted if it was built in 2013.
“If the highway were built today we would have constructed it at an elevation higher than what would be generated by Hurricane Hazel and it would be centred over the watershed,” said Tim Mereu, the VP of Environmental Services with the MMM Group – a construction project management firm.
It’s not just construction standards that could lead to future floods, Heralall said, but rather climate change that could lead to more frequent flooding.
“We’re seeing a little bit different weather, we’re seeing more frequent, more intense storm events. So while the roadway may have been designed for some level, that level is now being approached much more frequently.”
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