Uploaded March 2024 | Updated September 2026, 4 days ago
What effect does salt marsh vegetation have on the force of waves that reach the dike? Wetterskip Fryslân, together with Deltares, University of Twente and TU Delft and NIOZ, investigated the effect of salt marsh vegetation and open foreland on the force of waves that reach the dike. As a result, a dike may require less space and salt marshes may contribute to flood protection in the Netherlands. The research is funded by HWBP.
In September 2023, the water board removed blocks of soil from the salt marsh outside the dike east of the village of Peazens-Moddergat in Friesland. The blocks of soil were taken to the Delta Flume in Delft for research. A total of approximately 270 square metres of land was dug out. This amounts to 68 containers of soil, each 2 by 2 metres and 40 to 70 centimetres thick.
At the beginning of 2024, the blocks were carefully lifted into the five-metre-wide Delta Flume with a crane. Colleagues in the flume removed the walls and placed wooden beams to hold the blocks firmly together. They were then tightly pushed together with a powerful winch to ensure there are no gaps, with a walkway in the middle to inspect and maintain vegetation until the test begins.
We then simulated a super storm in our Delta Flume. We built a dike ten metres high and lay the blocks with salt marsh grass. We took various measurements. We used the wave height metres to measure the reduction in wave height above the salt marsh with vegetation. This way we can measure the wave-dampening effect of the salt marsh vegetation. We also looked at the erosion process of the salt marsh soil. When is the salt marsh vegetation broken down and the clay under the vegetation washed away? And what effect does the height of the vegetation have on the dike load?
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What effect does salt marsh vegetation have on the force of waves that reach the dike? Wetterskip Fryslân, together with Deltares, University of Twente and TU Delft and NIOZ, investigated the effect of salt marsh vegetation and open foreland on the force of waves that reach the dike. As a result, a dike may require less space and salt marshes may contribute to flood protection in the Netherlands. The research is funded by HWBP.
In September 2023, the water board removed blocks of soil from the salt marsh outside the dike east of the village of Peazens-Moddergat in Friesland. The blocks of soil were taken to the Delta Flume in Delft for research. A total of approximately 270 square metres of land was dug out. This amounts to 68 containers of soil, each 2 by 2 metres and 40 to 70 centimetres thick.
At the beginning of 2024, the blocks were carefully lifted into the five-metre-wide Delta Flume with a crane. Colleagues in the flume removed the walls and placed wooden beams to hold the blocks firmly together. They were then tightly pushed together with a powerful winch to ensure there are no gaps, with a walkway in the middle to inspect and maintain vegetation until the test begins.
We then simulated a super storm in our Delta Flume. We built a dike ten metres high and lay the blocks with salt marsh grass. We took various measurements. We used the wave height metres to measure the reduction in wave height above the salt marsh with vegetation. This way we can measure the wave-dampening effect of the salt marsh vegetation. We also looked at the erosion process of the salt marsh soil. When is the salt marsh vegetation broken down and the clay under the vegetation washed away? And what effect does the height of the vegetation have on the dike load?
Follow us on:
Facebook: facebook.com/DeltaresNL
LinkedIn: nl.linkedin.com/company/deltares
Instagram: instagram.com/deltares
