Characterization and Monitoring of Perched Aquifer (Saclay, France)

Perched aquifer are often complex hydrological systems and difficult to accurately characterize. These systems could be permanent or temporary and are created usually in the subsurface in the vadoze zone above another aquifer. The most common shallow lithology in Ile-de-France (France) is loam or clay formations. Because of their proximity to the surface, they are drained to limit the disruptive effect to the development of human construction or agriculture. However, they can also prove to be a useful resource for water plants and crops in times of drought when it is located deep enough. Many tools can be used to study the characteristics and the temporal evolution of the water. Thus, in this study, the CETEs Île-de-France has equipped the area of a number of piezometers containing probes that allow measurement point taken but also a continuous monitoring of the water level subsurface (fig. 2). Associated with these methods, geophysical campaign was carried out in order to have a vision in the area of the location of water and possibly find a connection between the various water points symbolized by the piezometers. For this, the ERT (Electrical Resistivity Tomography) and multi-frequency EM methods were done.