The hydro-morphodynamic response of a protected beach subject to sea storms: a numerical study

Sea storms are becoming more and more important in the economy of coastal areas, because they heavily affect both maintenance and life of the defense/touristic facilities, especially if they take place during the summer period. In conjunction with this, the design of traditional coastal defense structures is crucial for the protection of such facilities. The present study, based on numerical simulations performed by means of an innovative shallow-water numerical hydro-morphodynamic solver, explores the overall response of a protected beach to sea storms. Numerical tests have been run with the purpose of evaluating both i) the effect of real-life sea storms with different spectral characteristics, and ii) the influence of the positioning of shore-parallel submerged breakwaters on the beach morphology. The results of the simulations have revealed that erosion/accretion patterns depend weakly on the different sea storm conditions here used. On the other hand, the morphodynamics induced around the barriers is strongly influenced by the breakwater positioning: for the forcing here analyzed, the more the structures are offshore located, the more the bed variation is intense. On the opposite, the swash zone morphology is weakly influenced by the positioning of the breakwaters.