211-Grain-Size Evolution of Sediments Transported by Runoff Generated by Moving Storms.

Abstract

This study presents the results of laboratory experiments designed to investigate the influence of moving rainfall storms on the dynamics of sediment transport by surface runoff. Experiments were carried out using a soil flume. The movement of rainfall was generated by moving a rain simulator at a constant speed in the upstream and downstream directions along the flume. The main objective of the study was to characterize, in laboratory conditions, the distribution of sediment grain-size transported by rainfall-induced overland flow and its temporal evolution. Grain-size distribution curves were constructed using conventional hand sieving and laser diffraction for overland flow and sediment deliveries collected at the fl ume outlet. The results of laboratory experiments show that storm movement, affecting the spatial and temporal distribution of rainfall, has a marked influence on the grain-size characteristics of sediments transported by overland flow.