Stability of toe and scour protection

Local scour can occur at a breakwater constructed on a sandy seabed and may endanger the overall stability due to sliding of the main armour layer if the toe and scour protection is failing. The scouring pattern is a function of the water depth, wave conditions, sediment characteristics, and breakwater configuration and reflection characteristics as described by Arneborg et al (1996). A simultaneous current at the breakwater will significantly influence the scouring. Scouring in front of a berm breakwater constructed without a sufficient scour protection layer may result in berm stones to be moved into the scour hole, which will lead to further reshaping of the protecting berm. Physical two-dimensional (2D) model tests were made for qualitatively studying the scour development in front of a berm breakwater. Four test series were carried out in order to study the influence on the scouring and breakwater performance of varying the steepness of the incoming waves and of two types of scour protections.Berm Breakwater