Electrical resistivity characterization of the freshwater-saline interface: Implications for groundwater heat pump deployment in carbonate islands

Saline intrusion in coastal zones and islands must be carefully assessed and managed to avoid adverse environmental impacts on ecosystems and ensure the protection of freshwater resources for human consumption. This study employs electrical resistivity methods, specifically Vertical Electric Soundings, as the primary tool for characterizing aquifer salinity. Spatial variations in resistivity are analyzed and associating them with different salinity zones, allowing the delineation of the freshwater lens base. This information is essential for identifying aquifer conditions suitable for the deployment of Groundwater Heat Pump systems and for sustainable freshwater uses. Additionally, a preliminary comparative analysis between conventional Air Source and Groundwater Heat Pumps is presented, based on a one-year of experimental data. This comparative assessment provides an initial evaluation of the geothermal potential for the implementation of sustainable cooling systems in carbonate islands.