Saline intrusion: a potential risk for coastal aquifer management in sea level rise scenarios the case study of an adaptation plan for the municipality of Fano

Abstract

The work reported in this paper is part of a European Union project called ASTERIS and co-funded by the Interreg Italy-Croatia Cross-Border Cooperation Programme. The paper summarises the expected environmental changes resulting from North Adriatic sea level rise due to climate change, and the findings of a risk analysis of saltwater intrusion in coastal aquifers, at both regional and local scale. Starting from this scenario, and through a review of best practices, we set up an adaption plan with a view to mitigating the environmental and socio-economic damage due to the expected increase in salinisation along the coastal aquifers in the municipality of Fano (Pesaro province, Marche region, Italy). The municipal adaptation plan identifies the actions to be taken for sustainable use of groundwater, i.e. maintaining freshwater baseflow towards the sea, relocating the pumping systems to lower the interface zone, and creating barriers to saltwater ingression. The suggested adaptation measures were spatially distributed on the basis of the hydrogeological effects expected in the different zones of the coastal aquifer. These measures involve different groups of stakeholders playing key roles in the use of groundwater resources: owners of domestic wells, industrial and commercial water users depending on groundwater resources, managers of integrated water systems, urban planners, farmers, and tourist operators. Particular emphasis was placed on surface water bodies inside the town, which are in direct connection with seawater and exposed to salt wedge seepage during summers. Monitoring transects and threshold values were established in selected test sites. With regard to the progression of the saltwater intrusion process in future decades, “dynamic updating” of the adaptation plan, supported by field observations, appeared to be the most suitable method.