Electromagnetic methods and sensors for water monitoring

This paper deals with a brief presentation of non or minimally invasive techniques of interest for water security and monitoring applications, based on electromagnetic sensing. The techniques are presented according to the frequency range and to the degrees of novelty for the specific applicative context. For each technique, we briefly sketch the basic theory and the general and specific interest for the water monitoring. Besides well assessed techniques such as Electrical Resistivity, Electromagnetic Induction, Ground Penetrating Radar and Time Domain Reflectometry, Self Potential and Magnetometry, we give a short presentation of techniques of recent interest, some of them still in course of development, such as: Hyperspectral and TeraHertz Imaging.