How Do Spits, Bars And Tombolos Form?

Spits are also created by deposition. A spit is an extended stretch of beach material that projects out to sea and is joined to the mainland at one end.

Spits are formed where the prevailing wind blows at an angle to the coastline, resulting in longshore drift.

The development of Spurn Head 

1. Longshore drift moves material along the coastline.
2. A spit forms when the material is deposited.
3. Over time, the spit grows and develops a hook if wind direction changes further out.
4. Waves cannot get past a spit, which creates a sheltered area where silt is deposited and mud flats or salt marshes form.

*Longshore Drift - A tide or current that flows along the coast, taking material with it. 

• If longshore drift continues to extend the length of the spit , it may join up with the coastline on the other side of the opening, such as a bay.
• This results in the formation of a 'bar' with a 'lagoon' behind.
• The bar and lagoon at Slapton, Devon were formed when sea level was rising.

A tombolo is a spit connecting an island to the mainland. An example of a tombolo is Chesil Beach, which connects the Isle of Portland to the mainland of the Dorset coast.

Chesil Beach stretches for 18 miles. Lagoons have formed behind the stretch of beach material.