Holocene alluvial sediment deposition in contrasting environments in northwestern Europe

The total mass of Holocene alluvial sediment storage was estimated for three Belgian catchments (Dijle, Gulp and Amblève), with areas ranging between 47 and 1070 km2. The Dijle and Gulp catchments have comparable, rather intensive, land-use histories, while the land use in the Amblève catchment is less intensive and developed more recently. Topography is more pronounced in the Amblève catchment and more gentle in the Dijle catchment. In total, 1070 hand augerings were made to study fluvial deposition at 96 cross-sections across the flood plain. Average flood-plain deposition masses for the different catchments were calculated at different spatial scales. The results show that alluvial sediment storage is much higher for the Dijle catchment (464 103 Mg/km2 catchment area) compared to the Gulp (128 103 Mg/km2) and Amblève catchment (33 103 Mg/km2). Comparison with other data from West European catchments shows that alluvial sediment storage is much larger for the Dijle catchment, while that for the Amblève is very low. These differences between catchments can be attributed to their land-use history. Land use plays a role in both the soil erosion rates and in the sediment transport towards the fluvial system. Radiocarbon dating results for the Dijle flood plain indicate that major changes in land use are responsible for changing flood plain sedimentation.status: publishe