Burning Issues: Assessing Water Quality Challenges Post-Wildfire

Wildfires pose significant challenges to water treatment plants and freshwater systems by increasing sediment, nutrient, and dissolved organic matter (DOM) loads in streamflow, as well as exacerbating flooding through elevated runoff rates. This presentation by WWA Director Ben Livneh highlights findings from a multi-scale analysis that examines the effects of wildfires on sediment, nutrients, DOM, and runoff across multiple watersheds. We utilized laboratory-scale wildfire and rainfall simulations to explore small-scale processes influencing soil and water changes. Broad watershed-scale changes in water quality were assessed using 241 forested watersheds in the western United States. In burned watersheds, water quality was significantly altered during the first 2-3 years with changes to sediment and turbidity lasting up to 6 years. By assessing both small-scale mechanisms and broad-scale effects, this work aims to advance our understanding of wildfire impacts on watersheds and to identify key knowledge gaps.