The karst hydrostructure of the Verzegnis group (NE Italy)

In a quickly changing environment where drinking water appears ever more scarce and polluted, it is vitally important to study the quantity and quality of the available resources. With this in mind, the Verzegnis mountain group (Western Carnian Prealps, NE Italy) represents an important karst aquifer system upon which to draw water to supply inhabitants and industrial activities. The aim of this study is to highlight the state of the art of the resources present in the hydrostructure, understanding the recharge areas and characterizing the flow dynamics with a view to a sustainable exploitation. To complete this study, classical field surveys were conducted during which the main geochemical characteristics were analyzed. Measurements of water temperature (T), Electrical Conductivity (EC), Total Dissolved Solid (TDS), groundwater discharge (Q) and precipitation amount were performed monthly for a period of two years. The geochemical characteristics were defined using water sample analyses of the major ions and d18O values. The analyses performed and the resulting hydrogeological map allowed for a preliminary characterization of the hydrogeological behavior of the entire hydrostructure where the presence of tectonic structures and different lithological units represent a physical threshold for the waters. In fact, the groundwaters are mainly contained between the tectonic structure Douf—Auda thrust in the E, NE and a permeability threshold on the W created by the presence of the Dolomia di Forni Formation. In the southern side of the massif, a transcurrent fault creates a water divide between Mt. Verzegnis and Mt. Piombada.