Spatial Variability and Drivers of Salt Marsh Cliff Erosion in the Dutch Wadden Sea: From Observation to Simulation

Salt marshes are valuable coastal ecosystems that protect shorelines, but they are actively eroding, especially at the small cliffs along their edges. While earlier studies have linked wave energy to marsh erosion over long time scales and large areas, it remains unclear how well this relationship holds at smaller scales or during shorter events, such as storms. This study uses topographical data from drone imagery to determine local cliff erosion at a salt marsh in the Dutch Wadden Sea over a 9-month period. These observations are compared to a computer model that estimates erosion from wave energy. The model predicted overall erosion but missed small-scale local changes, showing that such models need local adjustments for better accuracy. The model assumes that erosion occurs only when water levels allow waves to reach the marsh cliff without overtopping it. Under this assumption, the results show that water levels strongly influence where and when erosion occurs. At this site, moderate yearly occurring storms caused more damage than more extreme storms that occur once every 5 or 10 years. These insights and the modeling approach can help predict where marshes will erode and inform better strategies for protecting coastlines using salt marshes. Read more here.