swashbackwash

Swashbackwash is a term used in coastal geomorphology to describe the two phases of wave action on a beach. Swash refers to the movement of water up the beach face after a wave has broken. This is typically a thin sheet of water that carries sediment with it. Backwash is the subsequent movement of water down the beach face, returning towards the sea. This phase is usually stronger than the swash and is responsible for transporting sediment seaward.

The interaction between swash and backwash is a primary driver of beach morphology. The energy of the waves, the angle of the beach, and the grain size of the sediment all influence the relative strength and characteristics of the swash and backwash. For example, steep beaches and coarser sediments tend to have a stronger swash, while gentler slopes and finer sediments are more influenced by the backwash.

This dynamic process can lead to different beach profiles. A beach with strong swash and weak backwash may build up over time, accumulating sediment and becoming wider. Conversely, a beach with strong backwash can erode, leading to a narrower beach or even a steeper profile. Understanding swashbackwash is crucial for coastal management, predicting beach erosion or accretion, and designing coastal defenses.