Optimization of Flood Protection Interventions in St. Mark's Square in Venice and evaluation of effectiveness through Geotechnical Investigations and Monitoring
Optimization of Flood Protection Interventions in St. Mark's Square in Venice and evaluation of effectiveness through Geotechnical Investigations and Monitoring
Venice is increasingly affected by flooding due to relative sea-level rise and subsidence. Although the MOSE movable barriers, operational since 2020, effectively limit extreme lagoon water levels, they do not prevent flooding in low-lying areas such as St. Marks Square. This study presents an integrated approach to optimize flood protection measures for the square, combining geotechnical investigations, long-term piezometric monitoring, and evaluation of implemented mitigation works. Since 2018, a dense piezometric network has monitored groundwater response to tidal forcing, MOSE operation, and local interventions. Results show a strong stratigraphic control on pore-pressure propagation: shallow anthropic fills respond rapidly to tides, while an underlying low-permeability silty layer markedly attenuates pressure transmission from deeper sandy units. Consequently, flooding is mainly driven by shallow hydraulic processes, including surface inflow and backflow through the historic drainage system, whereas deep seepage plays a minor role during high tides. These findings led to the adoption of targeted, minimally invasive measuressuch as drainage rehabilitation, backflow prevention, pumping systems, local pavement raising, transparent barriers, and wave protectionrather than extensive impermeabilization. Post-intervention monitoring confirms that the combined effect of local measures and MOSE operation significantly reduces extreme piezometric levels and flooding without altering the long-term groundwater equilibrium. The study highlights the key role of long-term monitoring in designing sustainable flood protection strategies for historic coastal sites.
Paolo Simonini; Francesca Ceccato; Ahmet Sevren
4th International Symposium on the Preservation of Monuments and Historic Sites
Restoration Engineering and Structural Interventions
https://doi.org/10.53243/tc301-2026-105