Driving the Modeling of Saltwater Intrusion at the Venice Coastland (Italy) by Ground-Based, Water-, and Air-Borne Geophysical Investigations

The coastland surrounding the southern Venice Lagoon, Italy, is a precarious environment subject to both natural changes and anthropogenic pressure. One major environmental problem is the saltwater contamination in shallow aquifers. Since the early 2000s, a significant effort has been devoted to understand the process dynamics by integrating different geophysical techniques, i.e. TL-ERT (Time Lapse - Earth Resistivity Tomography), MRT (Marine RT), AEM (Airborne ElectroMagnetic), and shallow water VHRS (Very High Resolution Seismic) surveys. The monitoring results have been used to drive the development of a reliable numerical model for the simulation of the saltwater intrusion along the margin of the southern Venice Lagoon. The model solves the coupled density dependent flow and transport equations by a highly accurate numerical approach based on the mixed hybrid finite element (MHFE) method and a combination of MHFE with high resolution finite volumes (HRFV) for the discretization of the flow and transport equations, respectively. Modeling application provides a clear picture of the relative importance of the factors that contribute to the soil contamination in the study area.