GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 3.2 ___ GNGTS 2023 Characterization of a coastal aquifer prone to saline intrusion at the Circeo National Park (LT) through inversion of ERT, TDIP and MASW data M. Cercato, G. De Donno, S. Maggiacomo, D. Melegari, G. Penta de Peppo Università di Roma “Sapienza” – DICEA Introduction Groundwater contamination can be caused by anthropogenic (e.g. intensive agriculture, industrial activities, emerging pollutants such as pharmaceutical products or microplastics, leachate spills outside the landfill areas, etc.) and natural factors, such as saline intrusion largely caused by overexploitation of coastal aquifers. The latter phenomenon can be worsened by climate change, which is expected to reduce rainfall in the Mediterranean regions and increase the frequency of extreme events, thus causing sea level rise (Cramer et al. 2020). Therefore, mapping and monitoring of soil and groundwater are pivotal for the appropriate management of the hydrogeological systems, as also stressed in the EU Water Directives (EU, 2000). For these goals, geophysical techniques are rapid, cost-effective and non-invasive tools for mapping and monitoring large areas down to significant depths. The geophysical results can be further validated through direct measurements and by the integration of different geophysical techniques. Currently, the development of a procedure encompassing different geophysical methods for the characterization of coastal aquifers is still an open problem in this research field. The present study aims to analyze the potential of the integration of electrical resistivity tomography (ERT), time-domain induced polarization (TDIP) with a full-decay inversion of the IP data and multi-channel analysis of surface waves (MASW) methods, for the assessment of the near-surface lithology and the prediction the relative permeability through the empirical relation after Weller et al. (2015). Study area, data acquisition and processing The study area (Figure 1) is located near Lake Fogliano in the Circeo National Park, about 70 km south of Rome, close to the Tyrrhenian coast. Starting from the results of a preliminary campaign,