Processes called erosion, mass movement and weathering break down and remove material from the coast. The material is moved along the coastline by the sea and deposited when there is energy loss.
When the sea loses energy, it drops the material it has been carrying. This is known as depositionWhen material is deposited or left behind, eg when a river loses its energy and is unable to carry its load any further, or waves move sand onto a beach but lack the energy to carry it away.. Deposition can occur on coastlines that have constructive waveWaves which help build up material on the beach. They tend to have a low frequency and strong swash..