How London’s Thames River was revitalized by accident

Thanks to a series of mishaps, the Springbank Dam has been stuck open since 2006 — and the ecosystem has thrived
By Tim Alamenciak - Published on April 28, 2017
a bridge over water and a Canada goose
The Springbank Dam has been stuck open for more than a decade, allowing a stretch of the Thames River to flow naturally — and a number of at-risk species to thrive. (Tim Alamenciak)

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Flowing through the heart of London, the Thames River has benefitted from accidental environmentalism for more than a decade now. Since a series of structural failures shut down the Springbank Dam — leaving it stuck in the “open” position since 2006 — a stretch of the river has returned to its natural flowing state, where previously there’d been a recreational pond.

That stretch is now home to North America’s largest concentration of the endangered spiny softshell turtle, plus several other at-risk species. With its natural flow restored, the river behaves as it should, flushing out pollutants and sewage overflow from rainstorms. All three of the area’s First Nations, along with the WWF and local fishers and conservationists, want to keep the river flowing — which means leaving the dam broken.

But area rowers say the working dam gave them valuable recreational waters. The London Rowing Club, headquartered in Springbank Park, says its membership has dropped precipitously with the dam closure — from more than 500 members to about 100. Rowers’ concerns were so great that, in 2003, an environmental assessment concluded the dam (which had been damaged by flooding three years prior) should be repaired largely because of them, calling the loss of recreational space an “overriding factor.”

The Springbank Dam has been in place in one form or another since 1870. It was designed to cut off the river near Storybook Gardens and Springbank Park, creating a recreational pond. Property owners on the north shore once enjoyed bucolic backyard scenes of rowers learning to row and the splash of oars as boats streaked across the water.

In 2003 the questions were whether and how to repair the dam, which was still operating but needed maintenance. At the time of the original assessment, the pond was full and nobody knew how damaging it was to the habitat. But Springbank didn’t permanently close until 2006, when repairs finally started. In 2008, part of the dam broke during testing, kicking off a series of lawsuits that kept it open.

“There is now an increased awareness of natural systems, species at risk and a growing body of knowledge about the negative impacts of water control structures. Our research alone shows a dramatic and positive change to the local natural system without the Springbank Dam,” wrote Scott Gillingwater, species-at-risk specialist with the Upper Thames River Conservation Authority, in an email.


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The dam harmed the ecosystem by keeping water levels artificially high, allowing nutrients and contaminants to concentrate in one area rather than flow through the river system. It deprived wildlife of the shallow pools they need to survive and acted as a barrier to animals looking to move up- or downriver.

There are between 1,000 and 2,000 spiny softshell turtles left in Canada, and the Thames is now home to the largest concentrated population of them. In April 2016, the species’ status was changed from “threatened” to “endangered” because of habitat loss across the country.

“If the dam were to be put back into use,” Gillingwater says, “this area would again provide little to no habitat for the spiny softshell turtle, and any gains this species has made in this area of the city would be lost.”

And it’s not just the turtles that stand to lose. According to Gillingwater, 17 of Ontario’s 26 species of snake and turtle call the Thames watershed home.

In 2014, current London Mayor Matt Brown campaigned on a promise to restore the dam to working order. City council will make a decision on that front after yet another environmental assessment — this time considering the entire eight-kilometre stretch as part of London’s “One River” plan, which also includes riverside development downtown. The report won’t be complete until 2018.

“When staff come back with a giant report,” says Councillor Tanya Park, “sometimes we have to refer things back because they sew everything together. If a report comes back in May of next year that's like that, we're going to have to refer it back to get it where it needs to be — that's the beginning of the municipal election.”

But staff are assessing a very different environment this time — one that nature has changed and will change further as council deliberates. The dam remains open, and the river flows unobstructed. Natural water-level fluctuations create shallow pools ideal for turtles. Snakes and fish thrive, moving freely through the river system. And although the water is murky, it is fast-moving — carrying runoff from farms and storm drains instead of letting it fester in an artificial pond.

“Dams are put in place for people,” says Gillingwater. “Rarely, if ever, do they positively impact the natural systems they have replaced.”

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