USING 137CS TO INVESTIGATE THE SEDIMENT BUDGET OF A CATCHMENT IN SOUTHERN ITALY

The sediment budget concept is largely accepted as providing a valuable tool for investigating the mobilization, transfer, storage and output from a drainage basin. Most work involving the application of environmental radionuclides in sediment budget investigations has focused on documenting rates of soil erosion and sediment delivery from agricultural fields or small basins. There is a need to explore the potential for upscaling the approach to larger areas or catchments. In fact, in such contexts, existing studies of catchment sediment delivery dynamics, relating on-site erosion and downstream sediment yield, have emphasized that only a small proportion of the sediment mobilized by erosion within a catchment may find its way to the catchment outlet. As the scale of the drainage basin increases, sediment budget investigations must consider both sediment delivery to the river channel and conveyance losses associated with large depressions or floodplain areas. This paper reports an example of the application of 137Cs technique in a medium-scale (31.6 km2) catchment aimed at assembling information on soil redistribution on the catchment slopes and on flood plain sedimentation rates. The overall results that are based on a catchment sediment budget deduced in a previous contribution, confirm that the use of 137Cs measurements, providing examples of both erosion and sediment redistribution of sediment on slopes and rates of sediment accumulation and storage on river floodplains, has a great potential in sediment budget investigations.