ELECTRICAL RESISTIVITY TOMOGRAPHY FOR COASTAL SALT WATER INTRUSION CHARACTERIZATION ALONG THE IONIAN COAST OF BASILICATA REGION (SOUTHERN ITALY)

Abstract

The first results of a research activity focused on the characterisation of the salt water intrusion along the Ionian coast of the Basilicata region (Southern Italy) are shown and discussed in this study. Along the coast there are many Sites of Community Interest (SCI) subjected to a strong incidence of human activities mainly linked to agriculture and tourism. Primary and secondary salinity of soil are linked to natural factors such as the climate, natural drainage patterns, topographic features, geological structure, distance to the sea and to the indiscriminate exploitation of the soil and groundwater resources. The approach based on the Electrical Resistivity Tomography (ERT) has been adopted to obtain high-resolution electrical images which allow to identify and delineate the geometry of litho-stratigraphic limits, by resistivity contrasts. Then, ERT represents an optimal tool for better reconstructing the geometry of the sea water intrusion front and mapping the areas characterized by a high level of salinization. In fact, the presence of seawater strongly reduces the resistivity values. For this reason it is necessary to evaluate if the contrast between the zones affected by saltwater intrusion and the geological layers