Many coastal areas are affected by aquifer salinization due to an unsustainable use of groundwater resources. Currently, few aquifer maps are available for areas subjected to salinization, since a quantitative assessment of soil and groundwater is not cost-effective without using non-invasive techniques for covering large areas with limited costs.
The key objective of this research proposal is the development of vulnerability maps related to aquifer salinization. The research project is intended to build a hydro-geophysical model derived from the acquisition of experimental non-invasive geophysical data of electrical resistivity tomography (ERT), complemented by geochemical, isotopic and geomatic data, in order to retrieve a 3D reconstruction of the studied area, where salinization-prone zones will be detected.
We aim to combine the resistivity model with the assessment of the capacitive behaviour of soil and groundwater (Induced Polarization - IP), by extracting the spectral information contained within the IP decay curve, directly correlated to the physical properties of the sediments. This new theoretical approach will be implemented in a numerical algorithm, which will constitute a further development of the software produced by the PI during the last five years. The subsurface model will be complemented by the assessment of the water table level, provided by a joint inversion of ERT and seismic tomography data. Additionally, remote sensing (LiDAR) and high-resolution multibeam bathymetry will provide surface and submerged (coastal lakes and rivers) information regarding salt accumulation. Finally, surface and subsurface data will be coupled in order to return a salinization map in the GIS environment.
The experimental method will be applied to two case studies in Central Italy (Tiber River mouth and Circeo National Park), where only low-resolution preliminary investigations are available and there is still a lack of vulnerability maps related to salinization.