This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Salt marsh sediment and vegetation can remain largely intact even during extreme storm surges. This was demonstrated in a large-scale experiment in which researchers transported sections of salt marsh to an experimental facility capable of producing the world's largest artificial waves.
The results show how salt marshes can contribute to natural coastal protection, both in the Netherlands and beyond. The results were published in the journals Nature and Communications Sustainability. Researchers from the University of Twente, Deltares, Wageningen University & Research, NIOZ, Delft University of Technology and other institutions transported sections of intact salt marsh from the Peazemerlannen nature reserve on the Frisian Wadden Sea coast to Delft and installed them in Deltares' Delta Flume.
There, a full-scale salt marsh covering more than 300 square meters (3,230 square feet) was created. The researchers then subjected it to increasingly higher waves, with significant wave heights reaching up to 2 meters (6.6 feet). In total, the salt marsh was exposed to waves for approximately 29 hours.
The experiment answered a key question for future coastal protection: Do salt marshes continue to function as natural breakwaters even during extreme storms, and can the plants that make up the marsh survive such extreme conditions? The stability of the salt marsh seabed was particularly striking. After 21 hours of wave action, the surface had dropped by an average of only 7 millimeters (0.28 inches).
The seabed thus remained virtually intact, even with waves up to 2 meters (6.6 feet) high. This is important for coastal protection. The elevated salt marsh seabed itself helps to slow down the waves.
The plants provide additional wave attenuation on top of that, but are gradually damaged during a storm. With waves of 75 centimeters (29.5 inches), the vegetation in the experiment provided 6% to 22% additional attenuation; with waves of 2 meters (6.6 feet), that was a maximum of 6%. In tests of different species representative of typical marsh settings around the world, surprisingly little plant material was lost—on average only 30%, and at least one-third of the plants remained even after the most extreme conditions.
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