Analysis of salinization processes in the coastal carbonate aquifer of Porto Torres (NW Sardinia, Italy)

The Porto Torres (NW Sardinia) coastal aquifer is hosted in the carbonate rocks of the Miocene succession,
which fills a NNW oriented half-graben. This aquifer is an important contributor to the fresh water supply
of the local area. It is increasingly being degraded by salinization processes, mainly associated with
intense groundwater over-exploitation. A combined hydrochemical and hydrogeological study has been
carried out to identify the origin of the salinity in the groundwater. The behavior of the major ions
showed that the changes in the chemical composition of the groundwater have been mainly controlled
by the encroachment of seawater, accompanied by cation exchange reactions. Since seawater intrusion
is a dynamic process, an Hydrochemical Facies Evolution Diagram, HFE-D (Gimenez Forcada, 2010)
approach was taken to establish whether the aquifer was in the seawater intrusion or in the freshening
phase. The assessment model developed provides regional authorities with a basic tools for sustainable
water management in the framework of multi-disciplinary research activities aiming to combat and/or
mitigate desertification and land degradation processes