Geochemical and cosmogenic tracers to define the aquifer’s vulnerability: the case study of the alluvial multi- aquifer system of the Friulian plain

Abstract The Friuli-Venezia Giulia Region (north of Italy) is characterized by the presence of high-quality freshwater resources which benefit local citizens, animals, and environmental habitats and also agriculture and production activities. In collaboration with the LTA consortium “Livenza Tagliamento Acque”, ENEA and the University of Ferrara, different kinds of waters from wells selected in the Fiume Veneto area were sampled and analysed to characterize them from a geochemical point of view. The results obtained made it possible to support the plans for the protection of water reserves formed by the multi-aquifer system of the high and medium Friuli plain, following the legislation of the water directive. It was also possible to define a circular and sustainable plan for the use of surface water resources respecting the natural recharge balances of aquifers, and the minimum flow of rivers and canals, taking into account the overexploitation due to unauthorized withdrawals. This study based on isotopic geochemistry makes available the estimation of the relationships between recharge capacity and water use of the Fiume Vento area in the Friuli Venezia Giulia region. This methodology allows defining the average age of the resources based on the time required for the recharge contributions to compensate for the losses induced by exploitation and resurgence.