New facility to study river abrasion processes

This technical note presents a new facility which was constructed in order to study sediment and bedrock abrasion processes during fluvial transport. These processes exert an important control on long-term landscape evolution but they are still poorly understood and inadequately quantified. The proposed experimental device is an annular flume with four fluid injections coupled to a close water circuit and a powerful pump, in order to reach hydrodynamic conditions up to whose prevailing in mountain streams. Fluid surface geometry and visualization experiments with a high speed camera allow us to monitor hydrodynamic variables and sediment motion during the experiments. Despite the circular geometry of the flume, pebble trajectories are found to closely mimic the bedload behavior in straight flume. Based also on a direct comparison with pebble abrasion rates along a large Himalayan River, we hypothesize that our device simulates in a realistic way transport processes and consequently abrasion processes in mountain rivers.