www.nonlin-processes-geophys.net/15/999/2008/ © Author(s) 2008. This work is distributed under the Creative Commons Attribution 3.0 License. Nonlinear Processes in Geophysics

Abstract. Due to the combined effect of wind and rain, the importance of storm movement to surface flow has long been recognized, at scales ranging from headwater scales to large basins. This study presents the results of laboratory experi-ments designed to investigate the influence of moving rain-fall storms on the dynamics of sediment transport by surface runoff. Experiments were carried out, using a rain simulator and a soil flume. The movement of rainfall was generated by moving the rain simulator at a constant speed in the up-stream and downstream directions along the flume. The main objective of the study was to characterize, in laboratory con-ditions, the distribution of sediment grain-size transported by rainfall-induced overland flow and its temporal evolution. Grain-size distribution of the eroded material is governed by the capacity of flow that transports sediments. Granulomet