Hydrogeological characterization throughout deep geophysical investigations in the Verrès plain (Aosta Valley, north-western Italian Alps)

Abstract

Although fresh water availability in the Aosta Valley (north-western Italian Alps) is generally granted by glaciers and snow seasonal melting at high altitudes, hydrogeological conditions are not favorable everywhere. Most part of the territory is typically mountainous, with prevailing metamorphic rocks and, secondarily, glacial deposits. Relevant ground water bodies can be found only in the main bottom valley, where glacial excavation, fluvio-glacial and lacustrine sedimentation had maximum intensity, allowing the deposition of important thickness of porous materials. Nevertheless, the geological knowledge of the subsurface is here still poor. These groundwater bodies are monitored by the Environmental Protection Agency of the Aosta Valley Region (ARPA Valle d’Aosta), according to the Italian law (D.Lgs.30/09). This study deals with geophysical investigations in the Verrès plain aquifer (southern Aosta Valley). The main goal of the study has been the first evaluation of groundwater research in potential deep aquifers. Different geophysical methodologies were applied (ERT, TDEM, HVSR, and Re.Mi.), in order to identify the deep aquifer geometry and the rock basement depth.