A multi-disciplinary team of utilities, academia, and consultants have convened to develop a study and publish guidance to improve water treatment resilience against the impacts of forest fires.

Critical to water security, forested watersheds provide 75 percent of the world’s accessible freshwater (Food and Agriculture Organization of United Nations 2021) and supply drinking water for more than two-thirds of North American consumers (EPA 2019). The frequency and severity of forest fires have been increasing globally with warming temperatures and shifting precipitation patterns due to climate change. Wildfires can cause costly, long-term water treatment issues that push water treatment processes beyond their design and operational response capabilities.

Such issues include filtration effectiveness, disinfection efficacy, the elevation of disinfection by-product formation, and increased bioavailable phosphorus leading to problematic cyanobacterial/algal blooms.

Led by a principal research team of Lynn Stephens (Brown and Caldwell), Dr. Mac Gifford and Yone Akagi (Portland Water Bureau), and Dr. Monica Emelko (University of Waterloo), Water Research Foundation (WRF) project #5168 is funded by the foundation’s Emerging Opportunities Program and the Portland Water Bureau (PWB).

PWB is designing a new greenfield 135 million gallons per day water filtration facility. This study will inform how to prioritize treatment changes due to wildfires and other events. Additional in-kind partners include Metro Vancouver, Medford Water Commission, and the City of Grants Pass.

The team will assess the ash characteristics of several past Northwest fires, including large amounts of ash collected by PWB from the 2020 Riverside Fire, which spread to over 138,000 acres. Ash collected by Seattle Public Utilities and Metro Vancouver from the 2022 Bolt Creek Fire and Minnekhada Fire, respectively, will also be analyzed.

This project has already been a successful collaboration between utilities to collect such large amounts of ash in an active fire zone. The team will use the large amounts of ash to conduct bench- and pilot-scale treatment experiments to evaluate the effectiveness of different treatment strategies. Moreover, specialized analytical monitoring to fully characterize organics and nutrient changes throughout the treatment process will be utilized.

“It is becoming more common for wildfires to impact drinking water supplies. This study will equip utilities with guidance on how to best enhance treatment resilience to climate change-exacerbated landscape disturbances, including but not limited to wildland fire,” said Stephens.

A key outcome of the study will be the prioritization of readily available adaptations to the water treatment process to respond to wildfire impacts and still meet regulatory, public health, and production requirements. The project is anticipated to take 15 months. Upon completion, a project report will be published and findings presented to the industry via a WRF webcast.