Evaluation of Post-Wildfire Debris Flow Mitigation Methods and Development of Decision-Support Tools. Final Report to the Joint Fire Science Program

摘要

In this study we analyzed the effectiveness of erosion control treatments in reducing post-fire debris-flow volume. We used detailed surveys of series channel cross sections in 46 basins in Colorado, Utah and California to develop graphs of the cumulative volume gain down the length of a channel. These graphs provide information about the relative magnitudes of contributions of materials to post-fire debris flows from hillslopes and channels. We also developed a multi-variate regression model that describes post-fire debris flow volume as a function of burn severity, basin characteristics and storm rainfall. This model was used to determine if post-fire debris flows can be effectively mitigated by reducing their potential volumes and to identify the size of basins that could be effectively mitigated. We also used field observations and information from emergency response personnel and practitioners to identify the most effective debris-flow hazard reduction methods.