Hamilton homeowners should think about where water would go in a flood, group says

With so-called one-in-100-years storms happening at least once a year now in Hamilton, Miranda Burton says preparing for potential flooding is more urgent than ever.

And that's why her organization is trying to mobilize people to do just that.

Burton, program manager for the Hamilton not-for-profit Green Venture, says they're trying to get Hamiltonians to look at overland water floor differently. 

Climate change is leading to more severe storms throughout the region, while development in Hamilton is expected to intensify significantly following city council's decision to maintain a firm urban boundary – meaning more pavement and fewer water-absorbing natural areas, she says.

"We're looking at wetlands that are being paved over, and we're running out of space for this water to go," says Burton, the program manager for Hamilton not-for-profit organization Green Venture. "It has to go somewhere. It's not just going to disappear."

Instead of directing water away from our houses and into the sewers — the traditional approach — Green Venture is urging people to create water-trapping green infrastructure on their own properties, she says. This can include swails, green roofs, and rain gardens – specially-constructed plant plots designed to soak up water and hold it there longer.

"When rain and snow falls in a natural environment, only 10 per cent will be runoff," Burton says. "In an urban environment, it's 55 per cent runoff."

Green Venture is offering a rebate of up to $500 for about 30 Hamiltonians who add green infrastructure projects to their properties this year through its Naturhoods program, which has been expanded following a previous pilot. Those interested can visit greenventure.ca/naturhoods and add their name to the rebate program email list to get more information.

"We want to be creating neighbourhoods that are able to deal with this issue of flooding, which is becoming more and more apparent," she said, noting the city gets the most flooding complaints from Wards 1, 2 and 13 – downtown, the west end and Dundas. 

The onus to prevent flooding may be more on the individual than some residents realize. Hamilton Water, the city's water management division, lacks an accurate picture of where excess water goes in major storms, according to a report presented by senior project manager Cassandra Kristalyn to the city's public works committee in December.  

"The city is lacking a comprehensive model that accurately captures both minor and major [stormwater] systems," the report says. "As a result, the city is limited in its ability to rapidly conduct post-flooding studies to identify and address any contributing factors to the flooding event. The city has insufficient visibility on where these systems are undersized or where flooding risks may exist."

In her comments to council, Kristalyn indicated that flood risk is very likely to increase.

"Climate change is altering the intensity, overall duration and frequency of climatic events and causing increases in precipitation volumes and patterns," she said. "This presents a critical challenge for city infrastructure. 

"There is also a risk that major stormwater paths do not exist in some parts of the city leaving streets and neighbourhoods vulnerable to flooding."