Storm waves damage marsh plants while the rooted platform holds
A full-scale Dutch experiment found that a salt-marsh platform remained largely intact under large waves even as its vegetation was damaged. Plants added more wave reduction at lower heights and much less under the largest waves. The peer-reviewed results separate the protection provided by rooted ground from that of standing stems, with shoreline-edge erosion outside the experiment.
Science··Night
A rooted platform faces large waves
A salt-marsh platform remained largely intact in a full-scale Dutch wave experiment even as the plants above it suffered damage.[1], [2]
Researchers moved intact blocks from the Dutch Wadden Sea coast into a large wave flume. The assembled platform covered 306 square metres. Trials lasted twenty-nine hours, including twenty-one hours with vegetation and eight after mowing, allowing the contribution of standing plants to be separated from that of the marsh ground.[1]
Plant protection changes with wave height
For waves 0.75 metres high, vegetation added six to twenty-two per cent attenuation beyond the platform’s contribution. At two metres, the added reduction fell to zero to six per cent. Plants retained only about a fifth to a quarter of their initial biomass, yet the rooted platform lowered by just seven millimetres.[1]
The tested surface is not an entire coastline
This single peer-reviewed study distinguishes erosion resistance of rooted soil from the declining wave reduction of damaged stems. Its seaward edge was protected, leaving lateral cliff erosion untested. Winter vegetation and the transplanted soil also define the conditions observed; the experiment does not measure how repeated storms and several years of vegetation loss would change a coast.[1]
