The 12th International Conference on Scour and Erosion (ICSE 2025)

The erodibility of the 700-years old Wadden Sea Dike in the Netherlands is an important consideration for the safety against flooding. To study the erodibility, an extensive research program was set up with field tests and full-scale wave flume tests. As part of the fieldwork, six borehole erosion tests (BETs) were performed according to the Briaud method. These BETs were the first recorded borehole erosion tests outside the United States of America. This research program also included accurate cone penetration tests (CPTs), geotechnical index tests on soil samples and different types of small-scale soil erosion tests. Afterwards, the full dike cross-section was temporarily excavated to map all sublayer intersections of the man-made soil. The borehole erosion tests provided valuable information on the residual erosion strength of the clay core of the sea dike. The tests gave relevant information about the soil heterogeneity, which is important for the erosion resistance against the forces of incoming waves on the seaward slope of the dike.