Here's how it works:
* Waves approach the shore at an angle: Waves rarely hit the beach directly. They approach at an angle, creating a zig-zag pattern as they break.
* Water movement: The water pushed up the beach by a wave will flow back down the beach at a slightly different angle than the incoming wave. This creates a net movement of water parallel to the shore.
* Sediment transport: This parallel current, called the longshore current, picks up sand and gravel particles, carrying them along the beach.
Other factors that influence sediment transport:
* Wave size and strength: Larger and stronger waves have more energy to move larger sediment particles.
* Tidal currents: The rise and fall of tides can influence the direction and strength of longshore currents.
* Seafloor topography: The shape of the seafloor can affect the direction and speed of currents.
Important note: Longshore drift is a major factor in the formation of beaches, spits, and sandbars. It also plays a crucial role in coastal erosion.
