Longshore drift occurs when waves approach the coast at an oblique angle, carrying sand and sediment in a prevailing direction. It is the primary mechanism of coastal sediment transport and responsible for forming spits, tombolos, and offshore bars.
Impact on Spanish beaches
On Spain's Mediterranean coast, drift generally moves from north to south. Construction of ports, groynes, and breakwaters interrupts drift, causing sand accumulation on the updrift side and erosion on the downdrift side. Managing this process is key to beach conservation and coastal protection against climate change.