Depositional landforms

Depositional landforms are produced on coastlines where mud, sand and shingle accumulate faster than they can be moved away by the waves.

Beaches are the most common depositional landforms. They result from the accumulate of material deposited between the storm and low tide marks. The sand, shingle and pebbles come from a number of sources. Much of its material that has been eroded elsewhere and that is being moved along the coast by longshore drift. Some comes from offshore as a result of waves picking it up from the sea bed and rolling it in towards the land. From the opposite direction, rivers feed mud and silt into the coastal zone via their estuaries (mouths).

Spits are long narrow beaches of sand or shingle that are attached to the land at one end. They extend across a bay, an estuary or where the coastline changes direction. They are generally formed by longshore drift in one dominant direction. At the end of the beach, the material being transported by longshore drift. This mainly occurs on the landward side (rather than the seaward side). The wind and waves may curve the spit towards the land.

If a spit develops in a bay, it may build across it and link the two headlands to form a bar. The formation is only possible if there is a gentle sloping beach and no sizeable river.