Adaptation to Saltwater inTrusion in sEa level RIse Scenarios (ASTERIS): hydrogeochemical surveys and aquifer modelling for groundwater behaviour assessing in the coastal areas of Fano and Ravenna (central-eastern Italy)

The Adriatic region is highly vulnerable to the adverse impacts of climate change. Although attention has been paid to understand the climate change impact and risks over the last decades, the Adriatic community still faces a lack of a common risk assessment. For this reason, ASTERIS project has been financed at the Call for proposal 2017 Priority Axis Safety and resilience of Interregional V Italy-Croatia 2014-2020 Program. To this overall objective, the project will provide two main outputs: i) a map of vulnerability to coastal salinization at the macro-regional scale (Adriatic) based on future scenarios for sea-level rise and the hydrological cycle and ii) best practice and guidelines for the management of vulnerable sites defined though the analysis of representative case studies in Italy and Croatia. Within these general purposes, hydrogeological and geochemical surveys in two specific shallow aquifer systems that develop in the coastal areas of Fano and Ravenna (central-eastern Italy), were carried out. Several periodical campaigns, aimed at measuring water level and physical-chemical parameters by vertical logs in wells or piezometers, were also conducted. Additionally, ground and surface water samples were also collected for chemical and isotopic analyses to define the compositional features and the main geochemical processes affecting the two shallow aquifers. Preliminary investigations suggested that the Ravenna shallow aquifer is already strongly spoiled by a significant seawater intrusion (up to 80 %), whereas at Fano the presence of the saline wedge can be regarded as negligible. This indicates that the aquifer system of Fano can be considered as a good proxy for evaluating and simulating potential processes of saline-fresh water interactions by either the increasing demand of water exploitation and sea level rise due to anthropogenic pressure and climate change, respectively. In order to simulate possible future ingressions of seawater in the aquifer system of Fano, groundwater flow and transport models are currently in progress. These models will be implemented and calibrated according to the hydrogeological and geochemical data collected within the framework of the ASTERIS project. The expected modelled scenarios, obtained through predictive simulations, are of pivotal importance for assessing the possible groundwater response to climate change and for a correct management and protection of water resources, which can be exported to other aquifers system along the Adriatic Sea.