Surge-tide interaction along the Italian coastline

Storm surge events are probably one of the most studied phenomena in coastal regions since they can lead to coastal flooding, environmental damage, and sometimes loss of human life. In regions of shallow water, among other localized processes, surges occurring at high astronomical tides tend to be damped while surges occurring at rising tides are amplified affecting water level extremes. This requires accounting for tide-surge interaction when defining the coastal hazards due to extreme water levels. Cities along the Italian coast, such as Venice, Ravenna, Bari (Adriatic sea), Genova, Livorno, Napoli, and Palermo (Tyrrhenian sea), are vulnerable to coastal flooding. Hence, a thorough understanding of the interaction between water level components, i.e., storm surge and astronomical tides, is required to define a proper framework for coastal risk assessment. Here, we analyze water level observations in several Italian coastal locations to investigate possible correlation and interaction between astronomical tide and the storm surge. Then we study the effect that such interaction has on extreme water level statistics to support the development of flood-resilient adaptation strategies.