Dikes play a very important role in protecting beings and goods. Existing fault zones reduce the dike stability. These fault zones cannot be avoided. This research project focuses on the detection of fault zones in order to prevent dike breakages during floods. For this purpose we are using a non-invasive geophysical method (geoelectromagnetic). This procedure is based on the identification of saturation lines and saturation velocity in the dike body using electromagnetical conductivity. These technologies are being tested under controlled laboratory conditions and in situ. Experimental tests are conducted in order to determine the influence of capillarity and imperfections on the saturation line and velocity. In order to reduce the number of laboratory experiments we are also working with numerical simulations using a two phase flow model (phases: air and water) in porous media.