Soil erosion and sediment deposition in the Belgian oess belt during the Holocene: establishing a sediment budget for a small agricultural catchment

Abstract

A method to establish a Holocene sediment budget for a 103 ha agricultural catchment representative for the Belgian loess belt is presented. Soil erosion and sediment deposition were determined based on 185 coring locations and a large excavation in the valley bottom. Results were integrated in a GIS and interpolation techniques applied to derive spatial patterns of erosion and sedimentation. Total soil erosion, sediment deposition and sediment export were calculated and the results show that volumes are highly dependent on the interpolation technique used. Sediment delivery ratios between 20% and 42% are derived and are consistent with data reported in previous studies. This clearly shows that the majority of the sediments produced during the Holocene have been stored near their source area and have not been delivered to the downstream rivers. The spatial distribution of soil erosion and sediment deposition within the catchment is strongly dependent on slope gradient and position within the catchment, which suggests that, since human impact began, topography has been the main factor determining long-term soil erosion and sedimentation.