Environment

From wasteland to wetland: re-naturalizing Toronto’s Don River into Lake Ontario

The $1.3-billion flood prevention project in Toronto’s Port Lands is one of the most ambitious urban nature restoration projects in Canada’s history

  • Feb 03, 2025
  • 1,013 words
  • 5 minutes
two workers in high vis kneel in vegetation that criss-crosses a water body. In the right, a bridge is crossing the water and there's an industrial scene in the background.
A view of the restoration work happening at the Port Lands in summer 2024, with the decommissioned Hearn generating station in the background. (Courtesy: Waterfront Toronto)
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Shannon Baker stops mid-sentence and points. “There’s a red-tailed hawk,” she says.

We watch the raptor cross low over the slow-moving river 50 metres to our left. It lands briefly in the thin, autumn-hued cover of bushes, plant stalks and sparse, bare trees on the north bank, then lifts off again.

“There he goes,” she says. “Hunting.”

Baker is a landscape architect and a director at Waterfront Toronto, the government corporation leading a multi-decade revitalization of swaths of aging, underused and derelict shorefront properties on the eastern edge of the city’s downtown core. Most days, she works in an office. But this late November morning, we’re touring the site of the project that’s been her focus for the last 8 years — one of the most ambitious urban nature restoration schemes undertaken in Canada’s history.

Red-tailed hawks are common in the city. What makes this one notable is it’s hunting in an area that for the last 100 years was a flat, infertile, toxic expanse of parking lots, factories, warehouses, marine terminals, wharves, oil tank farms and other industrial buildings. Yet today, a vibrant river valley runs through it.

That river is a 1.3-kilometre extension of the Don River, one of the primary Lake Ontario tributaries around which the city is built. Throughout Toronto’s early history, the Don emptied into Ashbridge’s Bay Marsh, one of the largest wetlands on the lake. But in the late 1800s, a concrete corridor called the Keating Channel was built on the marsh’s northern edge. Soon, the river was redirected into it — a new routing with a 90-degree right turn leading into the lake — while its original outlets and hundreds of hectares of marsh were filled in to create land for a new port district.

In economic terms, the new river extension and adjoining wetlands are a $1.3-billion flood prevention project. A century of hardening and distorting the Don’s natural channel meant it often spilled its banks. In that state, Baker says, the almost 300 hectares of surrounding port lands property — land that’s now earmarked for new housing and other mixed-use redevelopment — risked inundation in heavy storms.

The scale of the effort to solve that issue by creating a new, ecologically robust river channel has been immense: four-plus years of construction; roads lifted, moved and multiple bridges installed; 1.4 million cubic metres of contaminated soil excavated, treated and reused or replaced; a water-tight concrete-and-steel wall driven down to bedrock around the entire system to keep out the remaining toxins in perpetuity; two million herbaceous plants, 77,000 shrubs and 5,000 trees planted to establish a true array of native aquatic, wetland and forest habitats; and embedding of fabricated interlocking tree roots, soil lifts and other bioengineered materials to stabilize the channel walls and establish a mature landscape right out of the box.

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a yellow digger truck moves along a strip of what looks like hemp covered terraces under a blue sky
Construction and remediation work was done to stabilize channel walls. (Courtesy: Waterfront Toronto)
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under a yellow sky with silhouettes of electricty pylons, waterbirds swim on the hazy surface of a pastel river
The new channel connecting the Don river to Lake Ontario sees renewed wildlife this past fall. (Courtesy: Waterfront Toronto)
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That said, the goals don’t stop at flood control and ecological restoration. “For me, the project has always been about reconnection,” says Baker. “We’re reconnecting the river to the lake, but in this process, we’ve had so many opportunities to reconnect people. There’ll be a massive park space and over a kilometre of new river valley for them to explore, to be in connection with nature, right in downtown.”

Perhaps the deepest reconnections are with local Indigenous communities, whose settlements and trade routes on the Don and other rivers in the area predate the city’s creation by millennia.

Even before construction started, Waterfront Toronto engaged the MinoKamik Collective, an Elder-led Indigenous engagement and environmental design consultancy to provide input and coordinate wider Indigenous participation. Led by Elder Shelley Charles, from the Chippewas of Georgina Island First Nation, one of the group’s roles was to collaborate on the Indigenous planting palette for the site. “We were looking at wetland plants and what would help stabilize the riverbank, also plants that would have relationships with animals and what those connections are,” says Charles.

The plantings also included an unplanned bonus: during excavation, seeds from rushes that had laid dormant in the original marsh soil under seven metres of fill for a century started to sprout once they were exposed. Some were saved and later replanted. “It wasn’t a surprise to us when they hit that original soil that there were relatives and seeds in that soil,” says Charles. “It was like an ‘Aha’ moment when that happened and when those first plants started to grow … it was like, ‘Oh, you found us. We’ve been waiting for you.’”

Charles’ contribution also included bringing together an Indigenous Advisory Circle. Made up of Elders, youth, knowledge keepers and language speakers from different local Indigenous communities, including participant First Nations from the Williams Treaties, the Mississaugas of the Credit, and Inuit and Métis representatives, it had responsibility for naming the new park as well as the new island created from land now encircled by the new river and the old Keating Channel. It unveiled its choices in a recent ceremony, naming the island Ookwemin Minising, which means “place of the black cherry trees” in Anishinaabemowin/Ojibwemowin, and the park Biidaasige Park, meaning “sunlight shining towards us.” Indigenous design elements, such as a shade structure, fire holder, marker trees and sculpture, will be featured when work on the park is completed this year.

The Advisory Circle’s most recent return to the site for that naming ceremony was particularly emotional, says Charles. “When we met on the land at the start of the project, it was like we were on the moon, there was nothing there. It was like an artist’s canvas. Now when you stand in the same place today, and we’re able to walk along the river, it’s unbelievable.”

“The last couple of years have been pretty incredible in terms of how much has changed,” agrees Baker. But she also points out that people visiting the site today for the first time might not appreciate what’s been done. “Because when you look at the river now, it looks like it’s always been there.”

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