Spits

Spits are long narrow ridges of sand and shingle which project from the coastline into the sea. The formation of a spit begins due to a change in the direction of a coastline. The main source of material building up a spit is from long shore drift which brings material from further down the coast.

Where there is a break in the coastline and a slight drop in energy, long shore drift will deposit material at a faster rate than it can be removed and gradually a ridge is built up, projecting outwards into the sea - this continues to grow by the process of long shore drift and the deposition of material.



A change in prevailing wind direction often causes the end of spits to become hooked (also known as a recurved lateral).

On the spit itself, sand dunes often form and vegetation colonises (for example )

Water becomes trapped behind the spit, creating a low energy zone, as the water begins to stagnate, mud and marshland often begins to colonise behind the spit;

Spits may continue to grow until deposition can no longer occur, for example due to increased depth, or the spit begins to cross the mouth of a river and the water removes the material faster than it can deposited - preventing further build up.

An example of a spit can be found at Dawlish Bay, south Devon, jutting out into the mouth of the Exe Estuary.



The Western end of the spit,where it connects to the main coastline, is a bustling tourist resort, boasting a long sandy beach, sand dunes, and a challenging 18 hole links golf course.

Whilst the northwestern part hosts the 500 acre Warren Nature Reserve, which includes part of the River Exe estuary. The area is a Site of Special Scientific Interest (SSSI) with up to 8,000 wading birds resting at Warren Point at high tide. In addition, the site supports over 600 plant species, including the rare Warren crocus which is unique to the area. New species are still being found, notably the diminutive petalwort, an internationally rare liverwort.

This spit has reduced in size within the past century due to erosion partly caused by the installation of a Breakwater (structure) at Langstone Rock to the South West which traps sand from the local sandstone cliffs and interrupts the natural sediment flow of the area.

Links