While the incident was far from ideal, a recent sewage spill into the Bow River shouldn’t have any long-lasting health impacts on aquatic wildlife or the river itself, according to some scientists. Read More
While raw sewage can harm a water body’s health, the impact of the recent pipe leak on the Bow River should be mitigated by dilution, experts say
While raw sewage can harm a water body’s health, the impact of the recent pipe leak on the Bow River should be mitigated by dilution, experts say
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While the incident was far from ideal, a recent sewage spill into the Bow River shouldn’t have any long-lasting health impacts on aquatic wildlife or the river itself, according to some scientists.
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The City of Calgary confirmed last Friday that potentially hundreds of millions of litres of untreated sewage seeped into the Bow River between March 19 and 28, temporarily resulting in high E. coli levels in the river.
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The culprit was a leaky wastewater line that runs underneath the river near the Ogden Bridge, transporting raw sewage to the Bonnybrook treatment plant.
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A 2021 study published in Biological Conservation, an academic peer-reviewed journal, outlined that sewage pollution threatens biodiversity and ecosystem health by elevating the concentrations of unwanted “nutrients,” such as nitrogen and phosphorus, as well as pathogens like bacteria or E. coli.
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Alberta Health Services has not issued a health advisory regarding the Bow River incident, and city officials said Monday that testing of river samples collected every four hours had revealed water quality returned to normal shortly after the leak was contained.
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On Friday, a spokesperson for the Minister of Environment and Protected Areas said the province worked with the city and Alberta Health Services to test the water repeatedly, and worked with operators of downstream drinking water systems as well to keep them informed of the leak.
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“We are pleased that testing found no significant impacts to drinking water and there were no reported incidents of dead fish or wildlife from this release,” stated Ryan Fournier, press secretary for environment minister Rebecca Schulz.
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“We will continue to support the city’s damage assessment and repair options, if needed.”
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Municipal officials also pointed out the spill occurred far downstream of the intakes for either of the city’s water treatment plants, meaning there was no impact to the quality of Calgary’s drinking water.
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“We also know from modelling and other similar incidents in other cities that the material would have diluted quickly, minimizing effects downstream,” said Doug Morgan, the city’s general manager of operational services, on Monday.
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‘Dilution is the solution to pollution’
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Morgan’s comments were echoed by Cathy Ryan, a University of Calgary professor in the earth, energy and environment department. Her area of study includes hydrogeology, groundwater-surface water interaction and watersheds.