Percussion drillings in the floodplains reveal up to 10?m thick alluvial deposits. Combined sedimentological and geomorphological analysis suggests that the total sediment volume of the valley infill totals about 300,000?m3 of sediments. Radiocarbon dating documents that this alluvial sedimentation started during the sub-Atlantic period (between the 1st and 2nd centuries BC) and coincides with a shift from a flood-quiescent to a flood-prone phase. According to historical sources, the flood phase correlates chronologically with the Roman occupation of the area, when they practiced extensive logging in their territories. GIS modelling operations show a loss of soil surface of about 71?cm on average for the entire catchment (1,600,000?m3 loss of soil), if long-term land exploitation for wood supply is assumed. The modeling showed that approximately 80 % of the eroded soil has been fluvially transported out of the catchment, so the present alluvial plains may represent only about 20 % of the overall lost soil mass.