Soil erosion

Soil erosion is the process in which individual soil particles are detached and redistributed (PDF) to another location. Erosion is driven by two factors: water and wind. During this process, organic matter and nutrients can be washed out or blown away.

Soil erosion is a form of soil degradation. It can be fuelled by other types of soil degradation and can also contribute to further degradation. While erosion is a natural process, human activity, such as deforestation and agricultural practices, can make soils more vulnerable and accelerate erosion (PDF). In the Netherlands, soil erosion is a regional issue, mainly relevant in agricultural areas, with strong spatial and temporal variation depending on climate, relief, soil characteristics, land use, and soil management.

Erosion by water

Water erosion occurs (PDF) when flowing water picks up sediment in one place and deposits it elsewhere. When more sediment is removed from a system than enters it, erosion takes place. Over time, this can cause rivers to cut deeper into the soil. River erosion mainly occurs where there is a slope, which increases flow speed and erosive force. As a result, erosion is less common in the downstream sections (PDF) of Dutch rivers closer to the sea. In the Netherlands, different forms of water erosion occur: splash erosion, sheet erosion, rill erosion, gully erosion, tunnel erosion, and bank erosion. The type of water erosion is influenced by the impact of raindrops, the volume of surface runoff and the surrounding environment, such as soil properties and slope.

Erosion by wind

Wind erosion occurs (PDF) where soils are loose, dry and finely divided, where the surface is smooth and bare, and where wind speeds are high. High wind speeds generate strong erosive forces, although mainly smaller particles are transported. The extent of wind erosion depends on wind speed, soil properties and vegetation cover. In the Netherlands, wind erosion consists of four main processes: deflation, transport, abrasion and deposition.

Deflation occurs when wind detaches and lifts loose soil particles, which then enter transport. Transport can occur in three forms: surface creep (sliding or rolling of the largest particles), saltation (smaller particles being lifted and bouncing along the surface), and suspension (very fine particles carried at greater heights over longer distances). During transport, wind-blown particles can also wear away surfaces through abrasion, often described as sandblasting. Deposition occurs when coarser material settles close to its source and can cover soils, crops, roads, and other surfaces.

Impact of soil erosion

Soil erosion can significantly affect agriculture and forestry, but its impacts extend to water management, buildings and infrastructure in the Netherlands as well.

Water management

By lowering riverbeds and groundwater levels, erosion can affect both water quantity and system performance (PDF). Water intakes may become relatively elevated, reducing supply during droughts when demand is high. Bank erosion can undermine the stability of bridges, dikes and quays, while changes in bed levels may interfere with the functioning of weirs and limit the effective discharge of high water (PDF).

Agriculture

While unsustainable agricultural practices can induce soil erosion, erosion can reduce agricultural productivity in several ways. Lower groundwater levels may dry out soil (PDF), while intense rainfall can remove fertile topsoil and nutrients (PDF). Wind erosion further degrades soil by reducing organic matter, weakening structure and lowering water retention capacity. It can also spread fertilisers and pesticides.

Nature

A consequence of soil erosion, declining groundwater levels can lead to the drying of natural areas (PDF), including floodplains, with consequences for habitats and ecological processes. In some areas, such as the drift sands (zandverstuivingen in Dutch), wind erosion instead drives the formation and maintenance of this landscape, and this dynamic is actively being preserved.

Infrastructure & Built environment

As erosion deepens riverbeds (PDF), the river bottom lowers and fixed structures such as groynes and lock sills, as well as buried cables and pipelines, lie closer to the water surface. This can reduce navigable depth, limit vessel loading capacity, and expose infrastructure. Bed level changes can also create mismatches between the riverbed and locks or weirs, affecting their operation. This riverbed lowering is partly driven by sand and sediment shortages caused by upstream river management, where disrupted river flows can reduce natural sedimentation (PDF). In built-up areas, erosion-related declines in groundwater levels can dry out soils and contribute to subsidence (PDF).

Please note that, due to limited data and resources, and in line with expert guidance, this portal does not include information on risk assessment or data sources for soil erosion.