Minimizing economic impacts from post-fire debris flows in the western United States

For individual burned drainage basins, existing hazard models and readily available data can be combined in a geographic information system to rapidly estimate debris-flow-related damages following a wildfire. The results can then be integrated into an optimization model, whose output guides allocation of emergency management funds and selection of cost-optimized debris-flow management strategies for burned areas consisting of multiple drainage basins. This paper describes methods to identify and value elements-at-risk from a range of possible post-fire debris-flow scenarios, methods to integrate these results with common debris-flow mitigation techniques and best management practices, and methods to apply this information to optimize the mitigation decisions for burned areas. Despite the potential to transform the way hazard managers approach debris-flow mitigation decisions following wildfires, natural hazard and social science management models have not previously been linked in the literature. Results from Santa Barbara (California), Great Sand Dunes National Park (Colorado), and Colfax/Las Animas Counties (Colorado, New Mexico) study sites indicate that optimization modeling can be used to select natural hazard management methods whose benefit for mitigation of post-fire debris flows can easily outweigh the cost of implementation.