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Enhancing coastal resilience in the Netherlands

Just off the southwest coast of the Netherlands, an innovative solution to beach erosion has been motoring away since 2011. “De Zandmotor” – the Sand Engine or Sand Motor – is a two-kilometer wide artificial sand bar designed to erode.

Sand dunes and beaches have long protected the Dutch coast, but every few years the government has to ship in sand to replenish what is lost to erosion. With accelerating losses to these natural coastal barriers due to rising sea levels, and the growing financial and environmental costs that come with replenishing them, there arose a need for a new, more sustainable approach to protecting the coast.

An aerial map view of the Sand Motor
21.5 million cubic meters of sand form the artificial sand bar known as the “Sand Motor” on the Dutch coast (Wikimedia: Openstreetmap.org)

In 2006, a team of Dutch scientists and government officials devised a plan to build a large, hook-shaped peninsula by depositing far more sand than usual – about 21.5 million cubic meters – along the shoreline between Ter Heijde and Kijkduin, just south of The Hague. Over the course of twenty years, the wind and waves will sweep the sand from this peninsula along the coast through the process of longshore drift. This will expand beaches and build up sand dunes – bolstering the eroding coastline and protecting communities from flooding, while eliminating the costly need to dump sand in these areas every few years.

Construction of the Sand Motor concluded in 2011, and the results are promising thus far. The sand has spread north and south, creating widened coastal zones that are more resilient to rising sea levels. New habitats have emerged for a variety of plants and birds, and local residents are taking full advantage of the Motor’s recreational opportunities. The supply of sand in the Motor could continue to disperse for twenty to thirty years, surpassing initial estimates and mitigating the $80 million cost of its construction.

A diagram of the process of longshore drift
Sand spreads along the Dutch coast via longshore drift (Wikimedia: Fiveless)

The Sand Motor’s success has drawn international intrigue, and has spurred the building of two sand motors in Poole Bay and Norfolk, England. Officials in Peru and the U.S. have also expressed interest in implementing the idea.

Rising sea levels endanger coastal communities worldwide, and investments in resilience-building and disaster prevention strategies are increasingly important to their survival. As damaging environmental events become more frequent and volatile, creative solutions like the Sand Motor show promise of a new way forward.

Sources and Further Reading

Effects of beach replenishment on intertidal invertebrates: A 15-month, eight beach study. – Estuarine, Coastal and Shelf Science

In the Netherlands, a Better Way to Rebuild the Beach – Hakai Magazine

Protecting The Netherlands’ Vulnerable Coasts With A ‘Sand Motor’ – NPR

The coastline – longshore drift and spits – BBC

The Sand Motor – De Zandmotor