The Sand Motor: For Coastal Protection, Ecosystem and Recreation

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Nature attacks the coast in the Netherlands

The Dutch coast is constantly under attack by the sea. If dunes, dykes and water barriers were not maintained, the sea would reclaim many meters of land at some places along the coast every year. This is why the Dutch have long been famous for their battle against water. The threat from the sea is neutralised by sand replenishments. Near the city of The Hague such sand replenishments usually take place every three to five years. This sand is dredged from the bottom of the North Sea. As a result, plants and small organisms in some places along the coast are buried under mountains of sand every five years. The extraction of sand also disturbs the balance of life in the sea.

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Can we make the force of the sea work for us instead of against us?

Water management professionals and scientists have developed a bold idea based on their years of experience. They decided to deposit in one go an even bigger mountain of sand which the wind and sea currents will spread to where it is needed. And thus, the Sand Motor was born in 2011. It is called the Sand Motor because the driving force of the wind, waves and currents shifts the sand and reinforces the coastline. To create the Sand Motor, 21.5 million cubic metres of sand was deposited to form a peninsula on the coast. This is four to five times the amount of sand that is normally deposited. Initially this sand peninsula was five to seven metres high and protruded one kilometre into the sea. The total area: 125 hectares. This new method of depositing extra sand on to the coast is expected to last for 20 years rather than the maximum five years which until now was the case. It will also protect a much larger area of the coastline and provide a larger area and longer time for nature to re-establish itself.

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The Sand Motor goes its own surprising way

One of the most important goals of the Sand Motor is the strengthening of the coast without invasive activity. As nature plays the leading role, it is of course unclear what will happen. An intensive monitoring and research programme are closely following the movements of the Sand Motor. After five years this has delivered surprising results. The peninsula has flattened through erosion of its outer edge, and deposition of sand at the northern and southern areas close to the Sand Motor.

The reinforcement of the dunes is taking place slower than expected, but steadily, because the wind is transporting the grains of sand via the beach. It takes longer for the sand to reach the dunes via the lagoon created in the centre of the peninsula. This also means that the Sand Motor may be able to perform for much longer than 20 years and the added value for safety, recreation and nature will be longer too. Researchers from different disciplines and water management experts are looking together at the results. This means that new links are being made, the work that is done serves a direct practical goal and knowledge is being widely spread.

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Happy people and animals between unique flora

By not burying nature under a mountain of sand every few years, there should be room for the growth and return of unique species of plants and animals. Because the sand is spreading slowly, nature can grow with it. And this has already succeeded within five years! The protected blue sea thistle is already growing on the sand of the new dunes and small saltwater clams (Baltic clams or Limecola Balthica) have been spotted. The sheltered wetlands are also an important environment for food for coastal birds and at night and in the early morning’s seals take advantage of the raised sandbank to rest if tides are favourable. An additional effect of the sandbank is an increase in recreation. Not its primary aim but it was considered when the Sand Motor was being developed. The peninsula is ideal for walking and surfing. The creation of the Sand Motor has however changed the currents in the area. For the safety of swimmers and surfers, lifeguard organisations have developed an app so that they can monitor the currents. This app can be adapted for coastal areas around the world.

The Sand Motor is only a quarter of the way through its life so new and perhaps surprising developments will continue to emerge. But the first important conclusion can already be drawn: The Sand Motor works and the concept is suitable for use in other sandy coastal regions in the world. In Norfolk in England the first steps have already been taken. In the meantime, thousands of tourists enjoy sunbathing and kite-surfing on the coast of The Hague around the sandbank. The quality of the nature in the area is improving and the safety of inhabitants behind the dunes is guaranteed.