Smoke on water’s ecosystem has long-range effect from wildfires

Smoke isn’t the only way wildfires affect people and places far from the flames.

Researchers are studying how blackened forests affect ecosystems and water quality far downstream, as hundreds of blazes rage in B.C. and Ontario.

“Fires are particularly hard on water,” said Monica Emelko, a water treatment engineer at the University of Waterloo and a member of the Southern Rockies Watershed Project. “If the intensity is there and enough of the watershed is burned, you can have a very significant impact on the water supply and that impact can be long-lasting.”

The project began after southern Alberta’s 2003 Lost Creek fire. Its work has proven so valuable that the team recently received about $9 million in grants to keep studying how changes in forested areas affect water.

Fires and forests have always gone together. But that relationship began to change about the turn of this century.

Fire managers started to see wildfire behaviour that was at the extreme end or beyond anything that had been previously observed, said Uldis Silins, a University of Alberta hydrologist and project member. The intensity and speed of fires ramped up. Blazes that used to calm overnight kept raging. At Lost Creek, firefighters reported walls of flame 150 metres high rolling through trees at 2 a.m.

A 2016 paper found the effects of that fire were visible in rivers and streams more than a decade later. Run-off began earlier and was faster, increasing erosion and creating drier forests. Nutrients such as phosphorus were up to 19 times greater — good for aquatic bugs but also for algae.