Urban Stream Syndrome Hits Toronto

Toronto has come down with "urban stream syndrome" (USS).

That's the diagnosis from Angela Wallace, a biomonitoring analyst at Toronto and Region Conservation, in the most recent issue of Water Canada. She built evidence for her view in a scholarly article earlier this year. 

Data from an environmental monitoring project shows "that streams in the Toronto region have USS," Wallace wrote in her most recent piece. 

Population growth had provided the opportunity for the disease to take root. "The greater Toronto area has approximately 5.5 million people. This has put pressure on its approximately 3,654 kilometers of streams and watercourses," she said. 

Urban development is also associated with the disease. "The hardening of surfaces, such as roads and roofs, creates a landscape that makes it difficult to absorb rainfall," she said. 

Stormwater is a major culprit. It "causes streams and rivers to be more vulnerable to flooding, erosion, and pollution," she said. 

But Wallace said there is a cure. She pointed to "low-impact development" (LID). "LID has been identified as a management approach with the potential to help reduce the impacts of stormwater," she said. 

How would it work? 

"LID tries to alleviate the impacts of stormwater by managing runoff as close to its source as possible, therefore reducing the amount (and improving the quality) of stormwater that reaches our waterways. Examples of LID techniques include site naturalization, infiltration/soakaway pits, rainwater harvesting, permeable pavement, and green roofs," Wallace said. 

The term USS has been used for years to describe "the consistently observed ecological degradation of streams draining urban land," according to a scholarly article published by the North American Benthological Society several years ago. A key symptom is elevated concentrations of nutrients and contaminants, the paper said.  

Wallace is not the only one with concerns about water in Toronto. 

A report from the nonprofit Eco-Justice found earlier this year Toronto had some of the most polluted water in the province of Ontario. 

"Combined sewers use the same pipes to manage stormwater and sewage. The problem arises when large storm events such as July’s record storm overwhelm the sewers and cause raw, untreated sewage to seep into Lake Ontario," Global News reported, citing the study. 

For more on stormwater check out the Water Online Stormwater Resource Center

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