The rise in wildfire activity in municipal watersheds has created new uncertainties, unprecedented challenges, and substantial costs for drinking water utilities. Wildfires generate natural benefits to ecosystems, however, severe fires quickly transform forest floors, char vegetation and soils, and create a landscape susceptible to post-fire erosion and runoff to nearby surface waters serving as drinking water supplies. Consequently, source water quality can be highly variable and dramatically altered following fire resulting in increased sediments, nutrients, and dissolved organic matter (DOM), all of which challenge water treatment process performance and the delivery of safe drinking water. The results of several projects in collaboration with water providers in the western U.S. that address post-fire source water quality and implications for treatment processes will be discussed. Areas of emphasis include wildfire alterations to DOM character, DOM removal by coagulation treatment, and regulated and unregulated disinfection byproduct formation. In addition, more recent work has focused on investigating wildfire ash physicochemical properties, particle stability, and treatability. Lastly, a new transdisciplinary project in collaboration with researchers at OSU, WSU, and the USFS with the overarching goal of increasing fire resiliency among PNW water systems will be discussed. Collectively, our research aims to inform decision making by drinking water utilities as they prepare for and respond to wildfire.
Amanda Hohner is an assistant professor in the Department of Civil Engineering at Montana State University. She completed her M.S. and Ph.D. degrees in Environmental Engineering at the University of Colorado-Boulder and received her B.S from Washington State University. Her primary area of expertise focuses on the characterization of source water quality and drinking water treatment processes. Within this area, she evaluates the effects of climatic disturbances on watersheds and drinking water system resiliency. In my free time I like to adventure outside with my husband, son, and pup. In the winter we cross-country ski and in the summer we like to stand-up paddle board.