Longshore drift from longshore current is a geological process that consists of the transportation of sediments along a coast parallel to the shoreline, which is dependent on the angle of incoming wave direction. Oblique incoming wind squeezes water along the coast, and so generates a water current which moves parallel to the coast. Longshore drift is simply the sediment moved by the longshore current. This current and sediment movement occur within the surf zone. The process is also known as littoral drift.
Provincetown Spit, at the northern end of Cape Cod, was formed by longshore drift after the end of the last Ice age.
Timber groyne from Swanage Bay, UK
Picture showing the use of artificial headlands and detached breakwaters in a coastal system
A spit or sandspit is a deposition bar or beach landform off coasts or lake shores. It develops in places where re-entrance occurs, such as at a cove's headlands, by the process of longshore drift by longshore currents. The drift occurs due to waves meeting the beach at an oblique angle, moving sediment down the beach in a zigzag pattern. This is complemented by longshore currents, which further transport sediment through the water alongside the beach. These currents are caused by the same waves that cause the drift.
Dungeness Spit in the Strait of Juan de Fuca, on the U.S. Pacific coast.
Farewell Spit, on New Zealand's South Island