In order to estimate breach sensitivity of Flemish river dikes a conceptual method was developed. For each failure mechanism representative parameters are weighed and the outcome is a failure index for the considered failure mechanism. On basis of these failure indexes critical dike sections can be detected, which can be investigated in detail, including extensive geotechnical in situ and laboratory testing. Geophysical methods apt to give a first raw insight in possible weaker dike sections were investigated on their merits and results. For 2 typical dike sections geophysical methods were performed and compared with the results of standard geotechnical testing (CPT, borings).

It appeared that not all geophysical methods were useful, and even among those that proved to be valuable it is necessary to use a combination of different techniques for a good interpretation.