An AEM experience in Northern Italy. Innovative and multidisciplinary approach for a modern groundwater and land management

Climate changes are strongly affecting water supply all around the world and Northern Italy does not make exception to this. In addition, pollutant contamination due to human, both industrial and farming, activities is increasingly spreading in the high Po Plain region and its lateral valleys. Hence, in 2021 an AEM survey has been conducted, aiming at the identification of unknown water reservoirs, on an area of about 200 km2 located West of the Garda Lake. A time-domain transient EM system (SkyTEM) has been used to perform airborne measurements. To address the complex depositional environments typical of the subalpine region, the resulting geophysical data, joint with lithological data collected from wells in the last decades, have been interpreted through a cognitive approach. Where neither electromagnetic nor lithological data were available, a number of ground TDEM tests has been performed to cover the lack of knowledge. The 3D geological model has been constructed manually as a voxel model with lithofacies attributes supplemented by several bounding surfaces. Two different modelling methods have been combined, namely smooth and sharp, allowing to get the geological complexity. Starting from the geological model and based on an ad hoc piezometric campaign, carried out in the meanwhile on the same area, two 3D FEM flow models has been developed, namely a steady-state one and a transient one. These achievements have allowed us to understand complex operational situations and to manage them with robust awareness. In the light of these promising results, we have decided to extend the investigation on a wider area, covering further 1700 km2. The whole activity will provide a detailed database, from which impressive multidisciplinary applications can be inferred. Amongst them, priority will be given in kettling drought effects, assessing groundwater vulnerability and evaluating geotechnical phenomena, such as saturated loose sand liquefaction.