NL
Dutch coastal zone

Dutch coastal zone

Nature Based Engineering

Knowledge development for the Dutch coastal zone

Pilot programmes and experiments help to plan and execute sand nourishment better

Dunes are vitally important for the protection of the low-lying areas of the Netherlands near the sea. The sand in the coastal zone is also enormously valuable for nature and leisure activities. That is why the Netherlands has been maintaining its coastline structurally using sand nourishment since 1990. Sand nourishment is all about sediment levels. Is there enough sand in the dunes that serve as flood defences? In the beach zone? And in the Dutch coastal zone as a whole? Time after time, this strategy has received positive assessments. By comparison with the use of hard structures, it achieves policy objectives at relatively low cost and with relatively limited negative effects. The sand brought in during the nourishment operations is spread by the wind and sea, enhancing the natural character of the coastal zone.

As a result, the Netherlands has built up a tradition of investing in knowledge about the coast and the effects of sand nourishment. With Rijkswaterstaat, Deltares is responsible for building up that knowledge base. As the management authority, Rijkswaterstaat is ultimately responsible for the application of the knowledge.

Dutch coastal zone

Pilot programmes and trials help to improve the planning and implementation of the sand nourishment operations. For example, there has been an exploration of the concept of 'mega-nourishment', which involves bringing in an excess volume of sand in a single operation. This is expected to produce benefits in terms of less damage to nature, even better use of the forces of nature, lower costs and a temporary area for nature and leisure activities.

The first and most iconic mega-nourishment operation was the Sand Motor on the coast of South Holland. It was created in 2011: 128 hectares and nearly 20 million m3 of sand. Deltares played a leading role in the research leading up to the project and in the interim evaluation in 2016. The Sand Motor has turned out to be a success in most respects. The sand is spreading as expected and it is not moving out of the coastal zone. Nature and leisure activities are clearly benefiting, although dune growth is not as fast as expected. It is also important to note that the Sand Motor has boosted our understanding of the coast. Together with our fellow research institutes and universities, we have grabbed that opportunity with both hands. And the Sand Motor has turned out to be an iconic project for the Dutch business sector that generates worldwide interest.

The impact of climate change means that Dutch coastal management must continue to develop, and that also applies to our knowledge. Deltares and Rijkswaterstaat are conducting research to see what we will need in the future: how much sand, and where and how it should be deposited. The better we understand the system, the better our predictions can be. In the next few years, the focus will be on the complex sections of the coast in the delta areas and in the Wadden Sea. The basis for these efforts will, as always, be the research programme for coastal maintenance.

The coastal research allows us to plan the nourishment operations better: where, when, how much, for protection now and later, and a natural coast.
Quirijn Lodder & Carola van Gelder-Maas
RWS-WVL
The collaboration with Rijkswaterstaat ensures that the Netherlands continues to lead the way in working with nature on sandy coasts.
Marcel Taal
Deltares Expert Sea and Coastal Systems

For this project Deltares has collaborated with the following partners:

  • Wageningen UR
Marcel

Want to know more about this project?

Marcel Taal
Expert Zee en Kust Systemen
  • +31 (0)88 33 58 024
  • Marcel.Taal@deltares.nl
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