How wildfires can have a devastating, long-term impact on nearby water supplies

Monica Emelko arrived in Fort McMurray, Alta., in June 2016 to help study the impact of the wildfires. She says the devastation to people's homes and lives she witnessed changed her as a person. 

Emelko, the Canada Research Chair in water science, technology and policy at the University of Waterloo, was there to help ensure the drinking supply was safe for consumption as people readied to return to their homes.

Some researchers thought her team wouldn't even be able to detect an impact from the fires because the Athabasca River was already looking like tea before the fires. Heavy rains tend to send hot fudge-looking runoff from the land into the river, making it look like chocolate milk, she said.

Arriving after the fires, Emelko said she could see that hot fudge-looking flow enter the Athabasca's waters as ash, likely carrying nutrients like phosphorous and carbon, made the water supply challenging for treatment processes.

"Those [workers] were living in the water treatment plant, working hard to make sure that people could return to their homes and at least have safe water to drink," Emelko told Day 6 host Brent Bambury.

Canada is in the midst of an "unprecedented" wildfire season and experts say the escalating severity of the fires poses a compound threat to water supplies in their vicinity.

Officials in Nova Scotia have warned about the dangers of contaminates washing into wells. But if you don't rely on well water and live in a municipality or region where the water goes through a treatment plant, Emelko says contamination itself isn't really the problem.

"Drinking water providers do not distribute water unless it meets the criteria for health and safety that are common across the country," she said.

From a water treatment perspective the issue is mostly the strain contaminants pose to the infrastructure and supply.

"If the water is difficult to treat, we might not always have as much of it as we want at the quality that we want and need and on-demand."

Algae is one of those potential contaminants, says Emelko. Blooms of cyanobacterial (more commonly referred to as blue-green algae) are becoming a regular occurrence in parts of Canada, as seen in Nova Scotia. 

Every year after the 2016 fires, she says, there's been an algae bloom near Fort McMurray. Algae can clog filtration and limit the water treatment system's ability to keep up with demand. The infrastructure in Fort McMurray was built decades ago, before algae was a problem.

Algae can also create potential toxins that make people sick, but Emelko says those toxins haven't been found in Fort McMurray, and the drinking water is safe. But she cautions that toxins in the water supply could potentially still emerge.

Uldis Silins, a professor at the University of Alberta with a focus in forest hydrology, says that severe wildfires can affect watershed areas to the extent that health of a nearby river, and even its entire aquatic ecosystem, can change.