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What is a beach?
Beach
Beaches form in sheltered areas such as bays
Deposition occurs through constructive wave movement, where the swash (water that rushes up the beach) is stronger than the backwash (water that flows back towards the sea)
Beach formation usually occurs in the summer months when the weather is calmer
Sometimes sand from offshore bars can blow onto the shore by strong winds
Blown sand can create sand dunes at the backshore of a beach
What is a spit?
A spit is an extended stretch of sand or shingle that extends out to sea from the shore
Spits occur:
when there is a change in the shape of the coastline
OR
when the mouth of a river prevents a spit from forming across the estuary
A spit may or may not have a 'hooked' end, depending on opposing winds and currents
A good example is Spurn Point, which stretches for three and a half miles across the Humber Estuary in the northeast of England
Stages of spit formation
Sediment is transported by longshore drift
Where the coastline changes direction, a shallow, sheltered area allows for deposition of sediment
Due to increased friction, more deposition occursÂ
Eventually, a spit slowly builds up to sea level and extends in length
If the wind changes direction, then the wave pattern alters and results in a hooked end
The area behind the spit becomes sheltered
Silts are deposited here to form salt marshes or mud flats
Illustration showing spit formation
What is a bar?
Bar
When a spit grows across a bay, and joins two headlands together
A bar of sand is formed (sandbar)
Sandbars can also form offshore due to the action of breaking waves from a beach
Illustration showing bar formation
What is a lagoon, tombolo and barrier island?
Lagoon
A lagoon is where a small body of water is cut off from the seaÂ
They may form behind a bar or tombolo
Lagoons do not last forever and may fill with sediment and form new land
Tombolo Â
A tombolo is formed when a spit joins the mainland to an island
Chesil Beach in Dorset is a tombolo, as the mainland is joined to the Isle of PortlandÂ
Barrier Island
Barrier islands form parallel to the coastÂ
The main difference between a bar and a barrier island is that a bar joins two headlands, whereas a barrier island is open at one or both ends
Illustration showing the formation of a tombolo and barrier island