Trends & projections for coastal erosion

Sea level rise currently plays a relatively small role in coastal erosion along Dutch beaches, with a rate of around 3 millimetres per year (PDF) in recent years. However, this is expected to increase significantly in the coming decades. Depending on the climate scenario, the sea level rise may even become the main driver of coastal erosion in the future. This is especially the case for the Wadden Islands and, to a lesser extent, the south-western delta. The Royal Netherlands Meteorological Institute (KNMI)(PDF) projects that sea levels could rise by 0.5 to 2 metres by the end of this century compared to 2020.

Future coastal management

The Dutch knowledge institute Deltares (PDF) researched the impacts of future climate scenarios on coastal management. The study used projections with sea level rise rates ranging from 5 millimetres per year to 25 millimetres per year by 2100, corresponding to an extreme climate scenario (RCP 8.5). The study concludes that the current strategy of dynamic coastline management with sand nourishments remains sustainable (PDF) throughout the 21st century, even under accelerated sea level rise.

As sea levels rise faster, the required nourishment volumes and associated costs are expected to increase significantly. The yearly nourishment volume needed in 2100 is estimated to be 1.4 to 3.5 times (PDF) the current level of 11 million cubic metres per year. This means that nourishments will need to become more frequent and larger in scale. Research into more nature-friendly ways of nourishing beaches is therefore ongoing. Good management of the available sand resources in the North Sea is considered the most important step in ensuring a long-term continuation of coastal maintenance with sand nourishments.

Wadden Islands

According to the Sea Level Rise Knowledge Programme (PDF), the yearly nourishment volumes needed in the future will increase far less along the central Holland coast, where most economic activity is located, than along the south-western delta and northern Wadden coast. The Wadden islands are more vulnerable to coastal erosion caused by sea level rise, because the tidal inlets increase the area of coast that needs to be maintained. Nevertheless, there is technically enough sand available to maintain the Dutch coast over many decades to centuries.