Beaches

Beaches are the main feature of deposition found at the coast. They consist of all the material (sand, shingle etc.) that has built up between the high and low tide mark.

There are number of different sources of beach material - the main source being rivers, where fine muds and gravels are deposited at the river mouth.

Other sources of beach material include longshore drift (bringing material from elsewhere along the coast); constructive waves (bringing material up the beach from the sea) and from cliff erosion.

Click on the diagram below to see the main sources of beach material

A beach can be divided into different zones, and the activities that occuron a beach can be placed within particular areas (as shown on the diagram below). The most important function of a beach is to act as a barrier between waves and the coast.

Backshore
This area is not usually encroached upon by waves - unless storm conditions arise. Sand dunes and cliffs may be found as well as human activities such as golf courses, nature reserves, conservation and buildings.

Foreshore and nearshore
The foreshore is located closest to the backshore and it is here, due to the breaking of waves that sediment transport may take place. Much of the energy of waves is reduced (dissipated). The nearshore performs similar functions, but usually only at low tide.

Offshore
There is limited direct sediment movement here as tidal currents are more important than wave action.

On the beach itself, different features arise as a result of the action and strength of waves on sand and shingle.

As constructive waves build up beaches, they often form ridges in the beach known as berms. They are formed as sand/shingleis slowly moved up a beach by successive incoming tides - they are more commonon shingle beaches,The berm highest up the beach represents the extent to which the water has reached during high tide.

Whilst ridges and runnels are found more on sandy beaches. Both form 'crests'.