Planning: CHIRRP: Increasing resilience to fire through prefire assessments of postfire flow hazards: Co-producing solutions with communities

Increasing fire activity has exposed more communities, infrastructure, and resources to postfire flow hazards, including postfire debris flows and floods. Hazards associated with postfire flows include impacts to infrastructure and loss of life as well as long-term effects on water quality and reductions to reservoir storage capacity. Solutions to mitigate hazards and minimize risks associated with postfire flows include fuel reduction treatments, construction of sediment retention basins, public outreach and education, and planning evacuation routes. Implementation of mitigation strategies can be costly and time consuming, which limits the ability of communities to respond after a fire starts. This can be problematic since many postfire debris flows initiate in the first 60 days after fire and most initiate in the first year after fire. Prefire assessments of postfire flow hazards are therefore a valuable tool for mitigating the effects of postfire flows because they allow for additional time to evaluate and implement mitigation strategies. However, fundamental science questions remain that limit our ability to predict where postfire flow mitigation efforts are needed and which strategies will be most effective. This planning project will identify knowledge gaps and co-design the scientific approaches needed to evaluate solutions to proactively mitigate hazards and reduce risks associated with postfire flows before a fire begins. The project team will co-develop research questions with Yavapai County Flood Control District that, when answered, will fill key knowledge gaps in understanding of (1) fire effects on Earth surface processes, (2) uncertainty propagation through linked models within the context of hazard cascades, and (3) decision frameworks used by local agencies to mitigate postfire flow hazards. This project will also lead to the development of a place-based process for understanding prefire local decision-making regarding postfire flow hazards and risks. This framework can then be adopted and tested across diverse locations to optimize hazard and risk mitigation processes after fire. The success of this project will help identify areas at risk from postfire flow impacts and provide data for planning long-term flow control measures and mitigation needs, which will contribute to the protection of values at risk such as public safety and critical infrastructure. It will also provide training and professional development opportunities for graduate students and several early-career researchers. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.