How wildfires can have a devastating, long-lasting impact on nearby water resources

Monica Emelko arrived in Fort McMurray, Alta, in June 2016 to assess the impact of the forest fires. She says the devastation to people’s homes and lives that she witnessed changed her as a person.

Emelko, the Canada Research Chair in water science, technology and policy at the University of Waterloo, was on hand to ensure drinking water supplies were safe for consumption as people prepared to return home.

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

When Emelko arrived after the fires, she said she could see hot fudge-like stream entering the waters of the Athabasca as ash, likely containing nutrients such as phosphorus and carbon, making the water supply challenging for purification processes.

“That [workers] lived in the water treatment plant and worked hard to ensure that people could return home and at least drink safe water,” Emelko said Day 6 host Brent Bambury.

Canada is in the in the middle of an “unprecedented” wildfire season and experts say the escalating severity of the fires pose a compound threat to water supplies in their area.

Officials in Nova Scotia have warned of the hazards of pollutants washing into wells. But if you are not dependent on well water and live in a municipality or region where the water goes through a treatment plant, according to Emelko, the contamination itself is not really the problem.

“Drinking water suppliers will not distribute water unless it meets health and safety criteria that apply nationwide,” she said.

Contaminants burden treatment plants

From the perspective of water treatment, the main concern is the burden on the infrastructure and the supply due to contaminants.

“If the water is difficult to treat, we may not always have as much of it as we want, at the quality we want and need and on demand.”

LOOK | Fort McMurray’s water treatment costs could double after the 2016 wildfire

Fort McMurray’s water treatment costs could double after a wildfire

The cost of providing clean drinking water to Fort McMurray increased by 50 percent after the wildfire, and costs could reach 100 percent by 2017.

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

Every year after the 2016 fires, she says, there’s an algal bloom near Fort McMurray. Algae can clog the filtration and limit the water treatment system’s ability to meet demand. The infrastructure at 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 were not found in Fort McMurray and the drinking water is safe. But she warns that toxins in the water supply could still potentially form.

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

“It’s not until you start seeing those effects downstream, where people live in major urban centers, that people will really start to notice,” he said.

Up and down the food chain

Silins says wildfires can trigger what’s called a trophic cascade, an event that indirectly affects an entire ecosystem. In layman’s terms, he says, it’s not much more complicated than your “basic food chain.”

Healthy forests capture a lot of rain runoff, but when trees are burned or removed from a watershed, you get more water in rivers. So is the faster melting of snow when the tree cover is removed.

The runoff carries natural contaminants — such as organic carbon ash or sediments including phosphorus — through a river ecosystem.

“Phosphorus is especially important as a nutrient because in our part of the Rockies, phosphorus is the main nutrient limiting power productivity,” Silins said.

He said he has observed that when significantly more than normal phosphorus is added to the system, there is more vegetation and more aquatic insects, which in turn affects fish.

“We didn’t lose the clean water species, but we had immigration of species that are more tolerant of really degraded water quality. And the overall [species] population numbers went up.”

In the areas Silins has studied, those effects have been long-lasting.

He researched the serious 2003 Lost Creek wildfire in Alberta years after it happened. Then parts of Alberta, including Calgary, were then 2013 floodedhis team was in a rare position to chart the impact over a ten-year period.

“Even a decade after the fire, [the flooding] completely reactivated the disturbances and actually caused a seven to nearly nine fold increase in the production of sediments – phosphorus and some of these other water quality contaminants.”

Time to adjust

Silins notes that the areas of Alberta he studies have been battling wildfires for some time. It’s the severity and frequency that brings increasing complications – and it’s a global concern.

“I know there are land managers who are struggling with this problem and are really trying all sorts of things on the landscape all over the world.”

Emelko emphasizes that all levels of government in Canada need better coordination, better water treatment infrastructure and more water monitoring.

“If you don’t give [water treatment plant operators] with some insight into what’s coming through the pipeline or what’s coming through the river, literally, that upstream monitoring, you’re basically asking them to do things blindly.

She said she thinks awareness leads to a more adaptive mindset to the problem.

“When I started working in this area again [2004] we couldn’t even get funding for this problem. Fortunately, we were able to get some from the Alberta government, but people kept saying, ‘Oh, this is a one-time fire. That’s not a broader problem for Canadians to worry about.” And boy, [have] things have changed in a short time.”