Scientists from the University of Groningen and the Royal Netherlands Institute for Sea Research (NIOZ), in collaboration with the local water authority, have monitored wave run-up during storms over a three-year period. The results, which were published in the Journal of Applied Ecology, help the water authority to quantify the protective effect of salt marshes.

For three years, ecologist Beatriz Marin-Diaz always had one eye on the weather forecast during the storm season. "After a storm we had to visit our research area to assess the impact of the waves," she explains.

The research area was situated along the Wadden Sea, a shallow zone between a range of barrier islands and the northern coast of the Netherlands consisting of tidal flats and wetlands. "Most of our knowledge about the protection these marshes provide is from models. However, little data is available on what is really happening in the open air."

Observations

Along the coastline, Marin-Diaz has taken different measurements, such as elevation of the mud flats, the width of salt marshes, and the vegetation growing there. The impact of storms was assessed using wave loggers, but also by measuring the position of flood marks on the dikes. Next to the measurements she took herself, Marin-Diaz also received data on wind direction and strength from the Royal Dutch Meteorological Institute (KNMI).