Research shows wildfires can contaminate water quality up to eight years later

CENTRAL COAST, Calif. (KION-TV) -- In a recent study that discovered wildfires can affect water quality in surrounding areas for up to eight years.

The research, conducted by the University of Colorado-Boulder, looked at data points from 1984 through 2021 comparing burned watersheds and unburned basins across the western United States.

"Wildfires can dramatically alter water quality, resulting in severe implications for human and freshwater systems," the study said.

Up until now, researchers say that impacts on surrounding water basins in the aftermath of a wildfire had a surprising lack of in-depth regional analysis.

What the data from this study showed is elements, like organic carbon and phosphorus, at elevated levels in the first one to five years post-fire, while nitrogen and sediment show significant increases up to eight years post-fire.

Most wildfires result in an increase in sediment transportation and cloudy water. This could be due to rain, wind or water soaking into the ground.

The contaminants are then concentrating in the water and leaving potential for consumers to get sick, if not properly treated, according to officials.

With the fifth anniversary of the CZU fires approaching, the city of Santa Cruz continues to monitor their water supply.

"The city of Santa Cruz water quality is safe, we know that, but it's also important to understand that these concerns are very valid," Deputy Director of Water Administration Chris Coburn said. "We keep a close eye on the water and we measure the water quality during those events and then depending on that water quality we use, we utilize different sources so that the water quality is maximized that we give to our customers."

The study stated that these conclusions could potentially aid water managers in preparation efforts to wildfire impacts but that it would be costly.