Beach evolution occurs at the shoreline where sea, lake or river water is eroding the land. Beaches exist where sand accumulated from centuries-old, recurrent processes that erode rocky and sedimentary material into sand deposits. River deltas deposit silt from upriver, accreting at the river's outlet to extend lake or ocean shorelines. Catastrophic events such as tsunamis, hurricanes, and storm surges accelerate beach erosion.
Old sea level mark in the Bay of Pozzuoli before uplift in 1982–1984.
New quay at the Bay of Pozzuoli
St. Mark's Square, Venice, during flooding
Sea wall in the Netherlands that does allow the tide and organisms through, but brakes wave energy.
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
