Natural Dutch sand engine helps save English coastline

Low-lying coastal areas have always been under threat from soil erosion. However, climate change and rising sea levels have made these areas even more vulnerable to the elements. Storm surges, extreme spring tides and heavy storms are becoming more and more commonplace. And they are becoming increasingly destructive.

HAM 317 'rainbowing': spraying sand up onto the shoreline

HAM 317 'rainbowing': spraying sand up onto the shoreline

In the Netherlands, a multi-disciplinary research programme, NatureCoast involving 6 universities has developed a low-cost solution which works with nature rather than against it. The sand engine uses natural sandscaping technology. It is an example of the Dutch concept of Building with Nature which harnesses the elements to protect coastlines from erosion. Cooperation between knowledge institutes (Deltares and Imares), government and nature organisations (Province South-Holland, Rijkswaterstaat, Natuurmonumenten) and companies (RHDHV, Arcadis, Witteveen & Bos, Boskalis and Van Oord) led to its development.

Natural sea defences

In the east English county of Norfolk, residents had to consider moving inland when their sea defences started to fail. The soft cliffs near fishing villages Bacton and Walcott had been disappearing at a rate of 1 metre every 3 years for decades. The beach had disappeared and the coast came closer with every storm. A hard sea wall was not an option, because it would only shift the problem further along the coast. So Dutch expertise was called in to create a natural sand barrier. It only took 5 weeks to deposit 1.8 million cubic meters of sand off the coast. The sand was taken from deeper North Sea waters. The sand barrier provides a natural defence which continues to shift and change due to the constant currents. As a result, the sands shift further along the coastline using the natural energy of the sea.

Impact exceeding expectations

This idea was first piloted off the Dutch coast near The Hague. Here the waters are much shallower, which meant the 5-kilometre-long sand engine could be deposited 100 meters off the Dutch coast. Across the Channel, the depth suddenly plummets, which meant the 5-metre high sand bank had to be placed a lot closer to land. The sand engine along the Dutch coast is replenished every 5 years and results have shown that its impact is exceeding expectations. The English sand engine is roughly a tenth of the size of the Dutch version. It cost €22 million and should last up to 20 years.

The sand engine has saved 200 homes and brought the beach back, which means the area can once again be used for recreation. The return of a natural environment has enhanced dune formation and stimulated biodiversity. More wildlife and birds are coming back to what was once an area destined to be devoured by the sea.