RUNUP HEIGHTS AND REFLECTION COEFFICIENTS FOR A GENTLE SLOPE SEAWALL WITH STEEP STEPS

Abstract

 To reduce the wave runup height on gently sloping seawalls, a stairstep with a gentle slope is often introduced. This type of seawall with a gradual slope has the major disadvantage of occupying a wide area of beaches. To overcome this and utilize less space along the beach, stairstep type seawalls using concrete block units with a high height have recently been constructed to minimize the space required for such seawalls. The hydraulic properties for these types of seawalls are not yet well known. Using CADMAS-SURF numerical simulations, the wave runup and reflection coefficient values are examined and clarified. The results indicate that the reduced effects of runup and reflection are observed for within a certain range of the surf similarity parameter.