WRC Lecture- Amanda Hohner

Wildfire Disturbances to Source Water Quality and Drinking Water Treatment

Abstract: The recent rise in wildfire activity has raised concerns among water utilities that rely on forested watersheds, vulnerable to wildfire and strained by climatic pressures. Wildfire can quickly transform forest floors, char vegetation and soils, and create a landscape susceptible to post-fire erosion and runoff to nearby surface waters often serving as potable water supplies. As a consequence, source water quality may be dramatically altered following fire, including elevated particulate levels and dissolved organic matter (DOM) from debris and partially combusted biomass. Our research aims to inform decision making by drinking water utilities as they plan and prepare for wildfire. The results of several projects in collaboration with water utilities in Washington and Colorado will be discussed. Our approach involves field-based watershed monitoring studies, coupled with controlled laboratory experiments, and bench-scale treatability evaluations to address changes to DOM character and associated post-fire challenges to water treatment process performance. Our results indicated that wildfire altered the DOM quality and adversely affected treatability. The DOM was harder to remove by conventional treatment, due to a lower molecular weight composition and enrichment of organic nitrogen. Treatment operations will likely need to be adjusted to account for variable water quality to meet EPA Safe Drinking Water Act regulations, specifically following runoff events in fire-affected areas.

Amanda Hohner, Asst. Professor, Dept of Civil and Environmental Eng., WSU

3:10pm  |  Oct 17, 2018  |  PACCAR (PETB) 202 

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