MANAGING DEBRIS DAMS/BASINS AFTER WILDFIRES AND SUBSEQUENTSTORM EVENTS

摘要

In southern California, the mountainous areas that upslope from alluvial fans are highly susceptible to wildfires. Development on these fan areas must consider the possibility of increasing debris from mountain watersheds due to the frequent occurrence of wildfire events. Numerous debris dams have been constructed and maintained to protect public and private properties and lives. After a significant storm event, debris basins are excavated as soon as possible to restore the storage capacity before the occurrence of subsequent storm events. This is very important if the watersheds above the basins have experienced a recent wildfire. An accurate prediction of inflowing debris yields is a key factor when scheduling debris basin excavation. This paper presents a method to manage the debris basins based on the prediction of accumulated debris yields that result from a combination of wildfire and subsequent storm events using the Multi-Sequence Debris Prediction Model (MSDPM) developed at the University of Southern California. In addition, the potential utility as a managing tool is demonstrated by predicting sequence debris yields to schedule the cleanout operation of the debris basins and to develop a rapid emergency response strategy for debris-flow (mudslide) disaster in the arid and semiarid Southwest.