The French Public Works Research Laboratory and the Road Experimentation Center of Rouen installed an experimental embankment dam in order to monitor during long term geotechnical behaviour and more specifically electrical resistivity of the soil materials. The purpose is to evaluate water content evolution in the embankment dams made of fine compacted soil. Moreover a multitude of instruments were installed to survey water content, temperature, horizontal and vertical displacement in the engineering structure. Additional laboratory experiments on soil samples from the dam, permitted to identify the influence of temperature, water content and density on the measured electrical resistivity. By combining the field and the laboratory measurements, a model is developed, which corrects the measured resitivities to a reference temperature. Thus we are able to obtain a true resistivity section and convert it to a gravimetric water content section.