This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.
Post-fire water quality response in the Western United States
Wildfires are increasing in size and severity in forested landscapes across the Western United States. Not only do fires alter land surfaces, but they also impact the surface water quality in downstream systems. Data from 159 fires in 153 burned watersheds were used to identify common water quality response during the first five years after a fire. Within this large dataset, a subset of seven fires was examined further to identify trends in water quality response. Evaluating individual fires revealed strong initial increases or decreases in concentrations, depending on the analyte, that are masked when averaged over five years. Evidence from this analysis shows significant increases in nutrient flux (different forms of nitrogen and phosphorus), major-ion flux, and metal concentrations are the most common changes in stream water quality within the first five years after fire. Dissolved constituents of ions and metals tended to decrease in concentration five years after fire while particulate matter concentration continued to increase. Assembling this unique and extensive data set provided the opportunity to determine the most common post-fire water quality changes in the large and diverse Western U.S.
WF17115 Accepted 28 January 2018
© CSIRO 2018