Presenter: Carli Brucker, PhD, CU Boulder 
Title: Assessment of basin vulnerability to post-wildfire hydrologic and water quality effects through a multi-scale framework

Wildfires can significantly impact water quality and supply, presenting challenges for water treatment plants and freshwater systems. However, high variability and data scarcity in post-wildfire in situ water quality data have hindered previous analyses. Here, I present a unique multi-scale analysis of post-burn hydrologic and water quality effects, observing small-scale driving mechanisms as well as broad, large-scale responses across watersheds. Custom-designed laboratory-scale wildfire and rainfall simulation experiment apparati were first tested on 154 ~300 cm² soil samples. Burn effects were observed in the context of other key drivers—rainfall intensity and terrain slope—to simulate variable conditions in natural settings. A synthesis of previous wildfire simulation methods was also completed, discussing benefits and limitations of different techniques. Next, broad changes in constituent responses in post-fire years were assessed for 241 forested watersheds across the U.S. West using machine learning and statistical techniques. Inter-basin variability in post-fire responses was also attributed to physiographic watershed variables and wildfire characteristics. By bridging multiple scales, this study strives to provide a holistic understanding of wildfires’ impacts on watersheds in the U.S. West.