STRATEGIC CONTINUOUS WATER-QUALITY MONITORING IS FUNDAMENTAL TO UNDERSTANDING WILDFIRE EFFECTS ON WATER RESOURCES

Under combined conditions of drought, dry winds, high fuel loads, and multiple ignition points, the September 2020 wildfires in Oregon left a historic wake of destruction that has rapidly increased threat to water resources, including 56 drinking water supplies. Continuous monitoring downstream of burned areas by the USGS’s water-quality monitoring network in the Willamette River Basin has been modified with the intent of assessing how changes to runoff have increased loading of sediment, organic carbon, nitrogen, and phosphorus to the river systems, thus potentially increasing risk of disinfection by-products to drinking water users, harmful algal bloom occurrences in reservoirs, and depletion of dissolved oxygen during low flow periods. Here we recap what was monitored before, during, and after the September 2020 wildfires, and share our plan to increase monitoring in critical areas to better serve our partners and stakeholders as a starting point for understanding the long-term impacts of recent and future wildfire seasons. Strategically expanding continuous water-quality monitoring to fire-impacted areas supports, for example, development of early warning systems to downstream drinking water users.