MOUNTAINHYDRO: INTEGRATING GEOLOGY, GEOPHYSICS AND HYDROGEOLOGY IN A MULTIDISCIPLINARY APPROACH

Spring water represents a vital source of drinking water for local communities in mountain areas worldwide. As water demand and pressure on groundwater resources increase in a context of changing climate, there is a growing commitment to assess groundwater availability and to develop sustainable water supply strategies. Effective groundwater management relies on a comprehensive characterization of aquifer systems. In this regard, karst-fractured terrains pose unique challenges due to their complex and heterogeneous nature. This study focuses on the assessment of aquifer systems in karst-fissured mountain environments, by employing a multidisciplinary approach based on three pillars: geology, geophysics, and hydrogeology. The geological pillar centers on the construction of a 3D geological model derived from a combination of existing geological maps and targeted field observations. The model captures the spatial distribution of geological units and major structural lineaments and serves as a framework for the interpretation of groundwater preferential flow paths. The geophysical pillar involves the use of high resolution DC resistivity surveys and densely spaced transient electromagnetic (EM) methods, both ground-based and airborne. Geophysical surveys play a key role in capturing the subsurface heterogeneity and identifying preferential flow paths within the rock volumes. The integration of the geological model into the geophysical inversion through an iterative process provides insights into the hydrogeological characteristics of the investigated system and enhances reliability of the interpretations. Moreover, the 3D inversion of airborne EM data has proven effective in increasing model accuracy in topographically and geologically complex terrains. The hydrogeological pillar consists of groundwater chemical and stable isotope analyses, as well as hydrodynamic characterization. These analyses support the delineation of recharge areas of the springs and help characterize the behavior of the aquifer system. In addition, numerical simulations of groundwater flow were carried out to test different scenarios of recharge and flow paths in order to validate the conceptual model. The results demonstrate the strength of an iterative, integrated modelling strategy in improving the understanding of complex karst-fissured aquifers. Two representative study areas were selected to implement and validate the multidisciplinary approach: one in northern Italy (Val Sabbia, Lombardy), and the other in southern Spain (Sierra de Aracena, Andalusia). These sites exemplify geologically complex mountain terrains, providing robust testing ground for the methodology.