Seasonal bedload pulses in a small alpine catchment

Natural fluctuations of bedload transport under steady hydraulic conditions have been often attributed to the propagation sediment pulses in river channels, leading hysteretic patterns rating curves at both hydrograph and seasonal timescales. However, direct field observations pulse effect on rates rarely reported. Two datasets recorded a small Mediterranean badland catchment Southern French Prealps (Moulin Ravine Draix) are used here investigate originating from hillslopes response flow conditions. The first dataset comes long-term erosion monitoring program providing time-integrated yields since late 1980s by means large trap. second is based slot sampler fluxes 1-min time resolution autumn 2011. Sediment tracked with regular scour chain surveys along alluvial channel upstream station. Both revealed counterclockwise hysteresis which can be yearly reaching outlet during early winter. We believe that these could typical alpine catchments active gully bedrock sensitive frost-cracking processes.