Short-term post-wildfire dry-ravel processes in a chaparral fluvial system

摘要: Abstract Dry ravel, the transport of sediment by gravity, transfers material from steep hillslopes to valley bottoms during dry conditions. Following wildfire, ravel greatly increases in absence vegetation on hillslopes, thereby contributing supply at landscape scale. has been documented as a dominant hillslope erosion mechanism following wildfire chaparral environments southern California. However, alteration after initial deposition is not well understood, making prediction post-fire flood hazards challenging. The majority Big Sycamore Canyon burned May 2013 Springs Fire leaving ash and charred layer that covered ephemeral channels. Dry-ravel processes fire produced numerous deposits hillslope-channel transition zone. Field data focus on: 1) an post-wildfire dry-ravel pulse; 2) subsequent over seven-month period between September April 2014. We quantify geomorphic responses including one small winter storm generated runoff fire. measurements document volumetric changes derived ravel. Erosion mechanisms occurred within situated zone included: mobilization portion or entire deposit fluvial erosion; rilling surface unconsolidated deposits; 3) via continued supply; 4) mass wasting where profiles are near angle repose. Terrestrial LiDAR scanning point clouds were analyzed generate quantifying depth remaining first season. This study contributes understanding potential effects fine delivery systems ecosystems.