Coastal Transportation and Deposition

Long shore Drift

• Material is moved along the coastline by the waves.

• Waves will often approach the coast at an angle, carrying material with them. This is carried up on to the beach by the swash.

• The material is then dragged out to sea by the backwash, but this time it travels at right angles to the beach, as it will roll down the steepest gradient.

• This movement will slowly transport material laterally along the coast.

Sediment movement:

Long shore drift is the overall process of transportation, however the material actually moves through the four transportation processes seen in rivers. These depend on the size of sediment:

i) Traction - the rolling of large material along the sea floor by the waves.

ii) Saltation - the bouncing of slightly lighter material along the sea floor.

iii) Suspension - Small particles of material carried by the water.

iv) Solution - Material is dissolved and carried by the water.

Coastal Deposition:

• The process associated with constructive waves.

• Material is dropped by waves once they lose energy, either by rolling up a beach or where a river estuary causes a disruption to the normal movement of material along the coast.

• Creates features such as beaches, spits, bars and tombolos.