Aggradatie

Aggradatie is a geological process where the land surface is raised or built up by the deposition of sediment. This accumulation of material can occur in various environments, primarily along rivers, coasts, and in deserts. In fluvial systems, aggradation is often driven by increased sediment load from upstream erosion, or by a decrease in the river's velocity, causing it to drop its transported load. This can lead to the widening and shallowing of river channels, the formation of floodplains, and in extreme cases, the complete burial of existing landscapes.

Coastal aggradation occurs through the deposition of sand, silt, and gravel by wave and current action. This process builds up beaches, dunes, and barrier islands, and can be influenced by sea-level changes, sediment supply, and coastal morphology. Desert environments can also experience aggradation, particularly through the accumulation of wind-blown sand, forming dunes, or through flash floods that deposit sediment in ephemeral stream channels and basins.

The opposite of aggradatie is degradation, where erosion removes material and lowers the land surface. Aggradation is a fundamental aspect of landscape evolution and plays a crucial role in shaping the Earth's surface, influencing ecosystems, and impacting human infrastructure. Understanding aggradation is important for managing flood risks, coastal erosion, and interpreting geological history.