Physical and Numerical Modeling of Beach Response to Permeable Low-Crested Coastal Structures

Detached breakwaters are often employed to protect beaches against erosion. When these structures are frequently overtopped, they are named Low-Crested Structures (LCS). These LCS’s offer a number of potential advantages over conventional structures, but their functional design is extremely difficult due to the large number of different processes contributing to the resulting water/sediment fluxes and beach morphodynamics. These difficulties are increased when the structure is permeable, allowing the flow of water and sediments through it. The use of numerical and physical models can help designers to predict the beach response to this type of structures. In this paper, hydrodynamic and morphodynamic studies around permeable LCS’s have been carried out employing numerical and physical models. The main conclusion of this study is that both model types only reproduce some of the involved processes because the simulation of hydro-morphodynamics around permeable low-crested coastal structures is very complex. As a consequence, there are phenomena or processes that cannot be included in the modeling, so none of the tools available up-to-date can reproduce the whole problem.