Fighting floods with the pond before the storm

To help protect city basements from water damage after a large rainfall, grass craters are being dug in three parks to help control excess water

The city is fighting water with more water, using green infrastructure in its offensive against flooded basements.

Workers are carving ponds into three North York parks as part of a $17-million project, which includes more traditional fixes such as sewer upgrades for controlling excess stormwater, as part of the city’s basement-flooding protection program.

The undertaking includes dry ponds (grass craters that collect heavy rain in predictable pools) in Rustic Park and Gracefield Park and a wetland in Maple Leaf Park.

Relief efforts for residents in the Black Creek Dr. and Jane St. area have been “badly needed for upwards of a decade,” according to Nick Faieta, executive assistant to local Councillor Frank Di Giorgio.

“It’s a tough thing to have to vacuum out your basement — and air it out and dry it out, redo all the drywall — once every three or four years. Even to have to do it once . . . it’s a crazy ordeal to have to go through,” he said.

Construction in Maple Leaf Park began in September, with plans to finish the project by summer 2016. The entire project is set to be finished by spring 2017.

The multimillion-dollar plan is a drop in the bucket of the citywide anti-basement flooding program. Toronto Water’s most recent capital plan calls for $1.64 billion to fund the program over the next 10 years.

The work is a “high priority,” said John Kelly, an engineering director with the program.

Efforts expanded across the city in the wake of the July 8, 2013, storm that dumped almost 100 millimetres of rain in just two hours, prompting more than 4,700 basement flooding complaints to Toronto Water.

Though more ponds aren’t in the immediate plans to fight flooding, according to Kelly, with half the city’s land still to be studied for solutions, he said they will “always be an alternative.”

They require more space, but the ponds tend to be cheaper than other options, such as building underground holding tanks.

The ponds can also serve doubleduty as sports fields, among other things, he said.

Green infrastructure use is growing, University at Buffalo landscape and urban design professor Sean Burkholder told the Star.

“There is the idea if we can actually deal with storm water, and increase public space, and increase (animal) habitat all at the same time, why would we want an infrastructure that can only do one of those things,” he said.

Though a giant concrete ditch might be the fastest way to move excess water, it can only do that one thing, he said. Getting the natural world to “do work for us” can also be more cost effective in the long run, he added.

“The way the natural world can absorb fluctuations of various types, it does add this level of resilience,” he said.

Under the basement flooding protection program, two other dry ponds have been built already, in Moore Park and Muirhead Park in 2012.

Dozens of other stormwater ponds and constructed wetlands dot the city, many built to control water levels and quality in new developments, Kelly said.

In the case of the Etobicoke project, retrofitting the parks means chopping down 108 trees.

Despite the city’s pledge to replant double the number of trees and plants, not everyone is happy to lose the greenery, including mature willow trees.

Iana Karadjova has lived in a house backing onto Maple Leaf Park since 1998. Shielded from floods by a natural slope, she’s sympathetic about her neighbours, but disappointed the trees had to go.

“The park is populated with all kinds of animals: rabbits, squirrels. It’s like a different planet,” she said, days before workers started cutting down the trees.

“And now they’re trying to cut these big, big, beautiful trees. It was like an old English park, now it will become just like anything else.”

For the city, this was the best tool in their anti-flooding arsenal, while minimizing impacts to the community and the environment, Kelly said.

“We don’t simply go in and say there’s a park here, we’re going to use this park for stormwater retention during large storm events.”