Variations in suspended sediment grain sizes in flood events of a small lowland river

摘要

The grain size of suspended sediment and its variation during river flows is important information required for the modelling of river sediment transport and reservoir siltation, as well as for understanding the role of sediment particles in a variety of environmental processes. In this study, the results of grain size analyses of suspended sediment transported during flood events in a small lowland river are presented. The investigated area is the agricultural catchment of the River Zagozdzonka, a tributary of the River Vistula, located in the centre of Poland, approx. 100 km south of Warsaw. A total of 160 suspended sediment samples were collected in the period 2004-2007 during 11 flood events, caused by rainfall, snowmelt or a combination of both, and the samples were analysed for their particle size distribution. Mean values of the d_(50) of the suspended sediment for the events varied from 48 urn to 98 μm, and there was a tendency for an increase in particle size with increasing discharge.