$1B class-action claim alleges Oakville property owners at flood risk due to 'over-development'

A nearly $1-billion class action claim by Oakville property owners alleges that "over-development" in the town has led to increased flood risk, making their homes more prone to water damage and less valuable.

The claim, which has not been certified and has not been tested in court, is against the town of Oakville, Mayor Rob Burton, Conservation Halton, Halton Region, the town of Milton, and the Ontario government.

Burton told CBC Toronto the claim is "stupid" and a "political stunt."

The plaintiff class could include any property owner within an area of Oakville bordered approximately by Burloak Drive, Lake Ontario, Winston Churchill Boulevard and Dundas Street.

The claim alleges that "rampant" urbanization and the loss of "thousands of acres of once pristine  green space" upstream from this area has led to increased storm water runoff and flood risk in the downstream watersheds, including Bronte Creek, 14 Mile Creek and McCraney Creek.

The property owners are seeking $990,000,000 in damages.

Urban development dating back to the 1990s has altered water flow volume, the claim argues, forcing flood plain boundaries to be expanded downstream. Homes that were purchased outside of existing flood plains are now fully within the updated versions, the claim alleges.

This brings new restrictions on developing property, as the claim says owners have been unable to get permits for home additions, pools or decks. As well, the claim says the properties are less valuable, with owners now obligated to tell buyers they're within a flood plain.

Brenda Morrison has lived in South Oakville for 35 years. She said when she purchased her home, it wasn't on a flood plain, but it is now.

Morrison said the flood plain would have restricted her from putting in a pool and building an addition.

"It's made a big difference in the value of the home," she said in an interview.

While she was able to make upgrades to her property before the flood plain was expanded, she's now worried about resale value, as the area's large lots attract buyers looking to build big homes.

"But they wouldn't be able to. They'd have to stay within the footprint [of the existing home]," Morrison said.

Government was aware of risk, claim says

The claim argues that decision makers at multiple levels of government were aware that upstream development would increase the pressure on the storm water system closer to Lake Ontario.

"They were aware of that for decades," said Gary Will, one of the lawyers representing the property owners.

"They ignored those warnings and allowed the development to proceed, primarily because they needed the development dollars," Will said.

Rob Burton, the Oakville mayor, said the allegations are simply not true, and in an interview called the claim a "silly and frivolous effort."

He said that flood plains are continuously adjusted according to developing science and that the mapping in a century-old neighborhood like South Oakville would naturally require some changes over the years.

"To blame me for that isn't just frivolous; it's stupid," Burton said.

'Political stunt'

Burton also suspects there is political motivation behind the claim. One of the lawyers behind the claim, John McLaughlin, has unsuccessfully run for mayor against Burton twice.

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"This is a political stunt by political losers," Burton said.

Will said Burton's claim is "ridiculous," and added that McLaughlin is not planning to run in the next municipal election.

"There is nothing political about this. This is a serious claim," he said.

Urbanization vs. climate change

If the claim proceeds into a court of law, some the allegations will not be easy to prove, one expert told CBC News.

At its core, the claim blames increased flood risk in South Oakville on urban development. But there are other factors that can affect an area's risk for flooding, and the most important of those may be climate change.

Usman T Khan, a York University professor and an expert in water resource engineering, is not involved with the legal claim and did not comment on its specific allegations.

But he says it's difficult in general to "decouple" the effects that climate change and urbanization have on flood risk. He says determining that one played more of a role than the other is challenging.

"In many cases we lack sufficient detailed, long-term data to be able to do this with confidence," Khan told CBC Toronto.

"There is much uncertainty in this type of analysis."