Coastal landforms caused by deposition

how is material transported along coasts

longshore drift

explain longshore drift

- prevailing winds blow waves onto the coast at an angle

- the swash carries material up the beach in the same direction as the waves

- the backwash then carries material down the beach at right angles back towards the sea

- the material zig zags along the coast

what are constructive waves

Waves that deposit more material than they erode

characteristics of a constructive wave

- a strong swash and weak backwash

- with low wave height and long wave length

- occurs in calm conditions, without much wind

- powerful swash that carries material up the coast

- weak swash that cant remove much material from the coast

how is a spit formed

1. forms at sharp bends in the coastline such as a river mouth

2. longshore drift transports material past the bend and deposits it in the sea

3, strong winds and waves curve the end of the spit

4. the sheltered area behind the spit is protected from the waves and so lots of material accumulates there which means plants can grow there, over time this sheltered area can become a mud flat or salt marsh

how is a bar formed

1. when a spit joints two headlands together

2. the bar cuts off the bay between the headlands from the sea

3. this means a lagoon can form behind the bar