Bedload monitoring in a steep alpine stream: Results from the 2014 measurement campaign

In 2014, three high-frequency flood events (RI=1.1–1.7 yr) were investigated both in terms of sediment entrainment and bedload magnitude. The particle displacement was monitored using 250 PITtags installed in the streambed, while the Rio Cordon monitoring station enabled to characterize the bedload transport rate. In terms of displacement a clear difference was observed between the floods investigated. The near-bankfull events showed equal mobility conditions, with mean travel distance one order of magnitude higher respect to what detected in the under-bankfull event. In terms of bedload magnitude, only the near-bankfull events caused transport of coarse material to the monitoring station, depositing 113.0 t and 4.6 t. Both events peaked to 2.06m3s−1 but the bedload differs by more than one order of magnitude, proving that, currently, in the Rio Cordon the bedload appears more related to the sediment supply than to the magnitude of hydrological features.