Adaptation to Saltwater inTrusion in sEa level RIse Scenarios

The Adriatic region is highly vulnerable to the adverse impacts of climate change. Although attention has been paid to the understanding of climate change impact and risks over the last decades, the Adriatic community still faces a lack of common risk assessment. Particularly, water supply issues are an essential aspect in the development and sustainability of societal ecosystems. Coastal aquifers are characterised by a natural gradient towards the seaboard, where groundwater discharges into the sea. A saline wedge normally exists below lighter freshwater. The interface between freshwater and heavier seawater is in a state of dynamic equilibrium and the interface is a transition zone of mixed salinity. The flow of seawater toward freshwater aquifers on land, however, is also a common result of groundwater pumping and withdrawal for agricultural, industrial and other public purposes. With excessive pumping the natural hydraulic gradient towards the sea may be reversed and the intrusion can then extend to the pumping boreholes, which become saline. Plans for groundwater resource management demand a realistic estimate of future local sealevel response for a range of the most likely to the worst-case scenarios of global warming. It is, therefore, imperative understanding the interaction between fresh groundwater and seawater intrusion in a sea-level rise perspective to achieve a sustainable management of coastal water resources. Despite a general knowledge on climate-change driven sea-level rise, a down scaling approach to Adriatic scenarios, which represents a crucial pre-requisite for regional (realistic) estimate, is still not completely resolved. Moreover, the understanding of the influences of sea-level rise on salt ingression is not uniform at a local scale depending on a complex of factors for each site, including the hydrogeological setting, local rates of ground water extraction and hydrological regimes. The Italian and Croatian coasts are subject to the influences of touristic pressure, entailing the increasing extraction of groundwater in peak periods, and its effect on salt ingression, as well as the effects of pumping for agriculture during drought, which are often not taken into account in the management plan for water catchment. This project aims, on the basis of a common assessment of spatial and temporal variation in seawater intrusion, at identifying and mapping needs and barriers in risk management and to provide practical tools for a sustainable management through the identification of boundary conditions at a local scale. To this overall objective, the project will provide two main outputs: - A map of vulnerability to coastal salinisation at the macro-regional scale (Adriatic) based on future scenarios for sea-level rise and the hydrological cycle. - Best practice and guidelines for the management of vulnerable site defined though an analysis of representative case studies in Italy and Croatia.