U.S. Joint Fire Science Program


Date of this Version


Document Type



Fire Science Brief, Issue 45, May 2009


US government work.


Fire, burned landscapes, rain, debris flows—the sequence is familiar to most who live in or observe the western United States. Because even relatively small rainstorms can trigger debris flows on lands altered by fire, a variety of treatments such as mulching, seeding, and emplacing barriers and fences are used to reduce hazards. Based on measurements of debris flow volumes for 46 events, as well as field observations, surveys, and literature reviews, the scientists found hillslope treatments are most effective in reducing runoff and improving infi ltration. Conversely, channel treatments effectively capture debris, inhibiting these materials from joining and increasing the size of the debris fl ow. All treatments depend on proper design, installation, density on the landscape, and maintenance.