Linkage of slope wash and sediment and solute export from a foothill catchment in the carrathian foothills of south poland

摘要

This paper analyses the linkage between slope wash and sediment and solute export from the Stara Rzeka foothill catchment. Transport of sediment on slopes and its supply to the stream channel vary in time and depend on morphology and agricultural use of the area. Three threshold important for morphodynamics in a foothill catchment have been established as well as the role of slopes and valley bottoms in the supply of suspended matter to stream channels. When the first threshold is exceeded, occasional transport of material on a particular slope is initiated. When the second threshold is exceeded, local erosion is triggered on a slope. When we third threshold is exceeded, general transport of material on a slope takes place and is deposited in the valley bottom. When the second threshold is exceeded, the linkage between the slope and the channel is local. When the third threshold is exceeded, the connection between the two systems is general but still the majority of material transported from the slope is deposited on the footslope proluvial plains and in flat valley bottoms. In the Stara Rzeka foothill catchment, chemical denudation is dominant. However, the proportion of solute and sediment export is significantly larger in its subcatchment. This indicates that proluvial plains impede free sediment flux from the watershed divide to the channel and also that the solute transported by streams comes from the whole area of the catchment, while the source of the sediment is channel erosion.