Monitoraggio idrogeologico e criteri di early warning in un acquifero costiero soggetto a intrusione salina: il caso di Muravera (Sardegna sud-orientale).

The aim of this thesis is to contribute to the design of management systems for Sardinian coastal alluvial aquifers affected by saltwater intrusion, within the framework of the PNRR e.INS project, Spoke 9. The study focuses on the Quaternary alluvial aquifer of the Muravera coastal plain (Sardinia, Italy), selected as a pilot area because of the relevance of the salinization issue and the availability of a large body of previous data, further integrated with new monitoring tools and field activities developed in collaboration with the regional government and the regional environmental protection agency. The research investigates key processes that are still not sufficiently defined for management purposes, with particular attention to the relationships between the Flumendosa River, its tributaries, the hyporheic zone, and groundwater, seasonal piezometric variability, aquifer response to tidal forcing, the vertical distribution of salinity, and the vulnerability of the phreatic portion of the aquifer. To this goal, new monitoring points and techniques were implemented, continuous water level and electrical conductivity measurements were carried out, and new datasets were collected to update the conceptual model of the system. The expected outcome is the identification of criteria and indicators useful for an Early Warning System able to support groundwater management measures, including passive strategies such as pumping reduction and, in the longer term, the evaluation of Managed Aquifer Recharge (MAR) interventions as an active management option