Water quality data for selected post-wildfire watersheds in the western United States, water years 2021–2024

The U.S. Geological Survey (USGS) Water Availability Impacts of Extreme Events, Building Wildfire Capacity project, which aims to enhance the ability to assess and predict the impacts of wildfires on water supplies, monitored water quality in selected basins in the Western U.S, including California, Colorado, Montana, Oregon, and New Mexico, that were affected by wildfire in 2020–2022. Data for discrete water-quality samples collected during water years 2021 through 2024 are reported, including storm-event samples and baseflow samples. Analyses include ions, nutrients, dissolved organic carbon, and suspended-sediment concentration. Samples were analyzed by the National Water Quality Laboratory, Reston Stable Isotope Laboratory, and select sediment laboratories. A Site Information spreadsheet that contains site specific metadata, including drainage area, cumulative precipitation, and land use data, for each basin is also provided.