Research was done to understand the extent and the causes of several leakages in urbanized dikes in the city of Rotterdam. Hydrochemical analysis and 3D radar were part of the scope to understand the exact composition of the water and its possible sources and flow paths and to understand the subsurface and existing and/or unknown infrastructure that may play a role in the leakages. Various leaks were discovered and tracked back to their source, and mitigation measures were advised ranging from drainage to restoration.