A spit or sandspit is a deposition

Deposition (geology)

Deposition is the geological process by which material is added to a landform or land mass. Fluids such as wind and water, as well as sediment flowing via gravity, transport previously eroded sediment, which, at the loss of enough kinetic energy in the fluid, is deposited, building up layers of...

 landform

Landform

A landform or physical feature in the earth sciences and geology sub-fields, comprises a geomorphological unit, and is largely defined by its surface form and location in the landscape, as part of the terrain, and as such, is typically an element of topography...

 found off coasts. At one end, spits connect to land, and extend into the sea. A spit is a type of bar

Bar (landform)

A shoal, sandbar , or gravelbar is a somewhat linear landform within or extending into a body of water, typically composed of sand, silt or small pebbles. A spit or sandspit is a type of shoal...

 or beach

Beach

A beach is a geological landform along the shoreline of an ocean, sea, lake or river. It usually consists of loose particles which are often composed of rock, such as sand, gravel, shingle, pebbles or cobblestones...

 that develops where a re-entrant occurs, such as at cove's headlands, by the process of longshore drift

Longshore drift

Longshore drift consists of the transportation of sediments along a coast at an angle to the shoreline, which is dependent on prevailing wind direction, swash and backwash. This process occurs in the littoral zone, and in or within close proximity to the surf zone...

. Longshore drift (also called littoral drift) occurs due to waves meeting the beach at an oblique angle, and backwashing perpendicular to the shore, moving sediment down the beach in a zigzag pattern. Longshore drifting is complemented by longshore currents, which transport sediment

Sediment transport

Sediment transport is the movement of solid particles , typically due to a combination of the force of gravity acting on the sediment, and/or the movement of the fluid in which the sediment is entrained...

 through the water alongside the beach. These currents are set in motion by the same oblique angle

Oblique Angle

Oblique angle can refer to:*An angle which is not a multiple of 90°*Another word for "Dutch angle" in cinematography...

 of entering waves that causes littoral drift and transport sediment in a similar process.

Hydrology and geology

Where the direction of the shore inland re-enters, or changes direction, such as at a headland, the longshore current spreads out or dissipates. No longer able to carry the full load, much of the sediment is dropped, called deposition. This submerged bar of sediment allows littoral drift to continue to transport in the direction the waves are breaking, forming an above-water spit. Without the complementary process of littoral drift, the bar would not build above the surface of the waves becoming a spit and would instead be leveled off underwater.

Spits occur when longshore drift

Longshore drift

Longshore drift consists of the transportation of sediments along a coast at an angle to the shoreline, which is dependent on prevailing wind direction, swash and backwash. This process occurs in the littoral zone, and in or within close proximity to the surf zone...

 reaches a section of headland

Headland

A headland is a point of land, usually high and often with a sheer drop, that extends out into a body of water.Headland can also refer to:*Headlands and bays*headLand, an Australian television series...

 where the turn is greater than 30 degrees. They will continue out into the sea until water pressure (such as from a river) becomes too much to allow the sand to deposit. The spit may then be grown upon and become stable and often fertile. A spit may be considered a specialized form of a shoal

Shoal

Shoal, shoals or shoaling may mean:* Shoal, a sandbank or reef creating shallow water, especially where it forms a hazard to shipping* Shoal draught , of a boat with shallow draught which can pass over some shoals: see Draft...

. As spits grow, the water behind them is sheltered from wind and waves, and a salt marsh

Salt marsh

A salt marsh is an environment in the upper coastal intertidal zone between land and salt water or brackish water, it is dominated by dense stands of halophytic plants such as herbs, grasses, or low shrubs. These plants are terrestrial in origin and are essential to the stability of the salt marsh...

 is likely to develop.

Wave refraction can occur at the end of a spit, carrying sediment around the end to form a hook or recurved spit. Wave refraction in multiple directions will cause a complex spit to form. Incoming waves that come in a direction other than obliquely along the spit will halt the growth of the spit, shorten it or eventually destroy it entirely.

The sediments that make up spits come from a variety of sources including rivers and eroding bluffs, and changes there can have a large impact on spits and other coastal landforms. Activities such as logging and farming upstream can increase the sediment load of rivers, which may hurt the intertidal environments around spits by smothering delicate habitat. Roads or bulkheads built along bluffs can drastically reduce the volume of sediment eroded, so that not enough material is being pushed along to maintain a given spit.

If the supply of sediment is interrupted the sand at the neck (landward side) of the spit may be moved towards the head, eventually creating an island

Island

An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...

. If the supply isn't interrupted, and the spit isn't breached by the sea (or, if across an estuary, the river) the spit may become a bar

Bar (landform)

A shoal, sandbar , or gravelbar is a somewhat linear landform within or extending into a body of water, typically composed of sand, silt or small pebbles. A spit or sandspit is a type of shoal...

, with both ends joined to land, and form a lagoon

Lagoon

A lagoon is a body of shallow sea water or brackish water separated from the sea by some form of barrier. The EU's habitat directive defines lagoons as "expanses of shallow coastal salt water, of varying salinity or water volume, wholly or partially separated from the sea by sand banks or shingle,...

 behind the bar. If an island lies offshore near where the coast changes direction, and the spit continues to grow until it connects the island to the mainland, it is then called a tombolo

Tombolo

A tombolo, from the Italian tombolo, derived from the Latin tumulus, meaning 'mound,' and sometimes translated as ayre , is a deposition landform in which an island is attached to the mainland by a narrow piece of land such as a spit or bar. Once attached, the island is then known as a tied island...

.

The end of a spit attached to land is called the proximal end, and the end jutting out into water is called the distal end.

Spits around the world

The longest spit in the World is the Arabat Spit

Arabat Spit

The Arabat Spit , also called Arabat Tongue, is a spit which separates a large, shallow and very salty system of lagoons named Sivash from the Sea of Azov. The spit is located between the town of Henichesk, Ukraine, on the north and the north-eastern shores of Crimea on the south. It is separated...

 in the Sea of Azov

Sea of Azov

The Sea of Azov , known in Classical Antiquity as Lake Maeotis, is a sea on the south of Eastern Europe. It is linked by the narrow Strait of Kerch to the Black Sea to the south and is bounded on the north by Ukraine mainland, on the east by Russia, and on the west by the Ukraine's Crimean...

. It is approximately 110 km long.

The largest spit in the United States is the Dungeness Spit

Dungeness Spit

Dungeness Spit is a long sand spit jutting out from the northern edge of the Olympic Peninsula in northeastern Clallam County, Washington, into the Strait of Juan de Fuca. It protects Dungeness Bay. The Dungeness Spit is entirely within the Dungeness National Wildlife Refuge and home of the...

 on the Olympic Peninsula

Olympic Peninsula

The Olympic Peninsula is the large arm of land in western Washington state of the USA, that lies across Puget Sound from Seattle. It is bounded on the west by the Pacific Ocean, the north by the Strait of Juan de Fuca, and the east by Puget Sound. Cape Alava, the westernmost point in the contiguous...

 in Washington (8.9 km).

Farewell Spit

Farewell Spit

Farewell Spit is a narrow sand spit situated at , at the northern end of the South Island of New Zealand. Known to the Māori as Tuhuroa, it runs eastwards from Cape Farewell, the island's northernmost point...

 in New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

, at 32 km, is one of the longest in the world. Farewell Spit, in the North West corner of the South Island

South Island

The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...

 is believed to be caused by the strong prevailing winds and currents bringing sand eroded from the Southern Alps

Southern Alps

The Southern Alps is a mountain range extending along much of the length of New Zealand's South Island, reaching its greatest elevations near the island's western side...

 of the South Island and depositing these into Golden Bay.

Spits in the UK are caused by prevailing South-Westerly winds, which give the spits their direction. However, when the direction of the wind changes for a short while the spit may change in direction for a short while forming a hook. Many spits have hooked or curved ends. One spit in the UK can be found in Dorset

Dorset

Dorset , is a county in South West England on the English Channel coast. The county town is Dorchester which is situated in the south. The Hampshire towns of Bournemouth and Christchurch joined the county with the reorganisation of local government in 1974...

. Chesil Beach

Chesil Beach

Chesil Beach, sometimes called Chesil Bank, in Dorset, southern England is one of three major shingle structures in Britain. Its toponym is derived from the Old English ceosel or cisel, meaning "gravel" or "shingle"....

 is an 18-mile long shingle that connects Weymouth to the Isle of Portland. Chesil Beach provides shelter to Weymouth and the village of Chiswell from prevailing winds and waves.

The Curonian Spit

Curonian Spit

The Curonian Spit is a 98 km long, thin, curved sand-dune spit that separates the Curonian Lagoon from the Baltic Sea coast. Its southern portion lies within Kaliningrad Oblast, Russia and its northern within southwestern Lithuania...

 off the cost of Lithuania

Lithuania

Lithuania , officially the Republic of Lithuania is a country in Northern Europe, the biggest of the three Baltic states. It is situated along the southeastern shore of the Baltic Sea, whereby to the west lie Sweden and Denmark...

 and Kaliningrad Oblast

Kaliningrad Oblast

Kaliningrad Oblast is a federal subject of Russia situated on the Baltic coast. It has a population of The oblast forms the westernmost part of the Russian Federation, but it has no land connection to the rest of Russia. Since its creation it has been an exclave of the Russian SFSR and then the...

 (Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

) separates Curonian Lagoon

Curonian Lagoon

The Curonian Lagoon is separated from the Baltic Sea by the Curonian Spit. Its surface area is . The Neman River supplies about 90% of its inflows; its watershed consists of about 100,450 square kilometers in Lithuania and the Kaliningrad Oblast.-Human history:In the 13th century, the area around...

 from the Baltic Sea

Baltic Sea

The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...

 and is 98 km long. In a similar fashion, the Vistula Spit

Vistula Spit

The Vistula Spit is a spit, or peninsular stretch of land, which separates Vistula Lagoon from Gdańsk Bay in the Baltic Sea. The border between Poland and Kaliningrad Oblast, an exclave of Russia, bisects it, politically dividing the spit in half between the two countries. The westernmost point...

 separates Vistula Lagoon

Vistula Lagoon

The Vistula Lagoon is a fresh water lagoon on the Baltic Sea separated from Gdańsk Bay by the Vistula Spit. It is sometimes known as the Vistula Bay or Vistula Gulf. The modern German name, Frisches Haff, is derived from an earlier form, Friesisches Haff. Both this term and the earlier Polish...

 from the Gdańsk Bay

Gdansk Bay

Gdańsk Bay or the Bay of Gdańsk or Danzig Bay is a southeastern bay of the Baltic Sea. It is named after the adjacent port city of Gdańsk in Poland and is sometimes referred to as a gulf.-Geography:...

 off the coast of Poland

Poland

Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

.

Human settlement patterns

Since prehistory humans have chosen certain spit formations as sites for human habitation. In some cases such as Chumash Native American

Indigenous peoples of the Americas

The indigenous peoples of the Americas are the pre-Columbian inhabitants of North and South America, their descendants and other ethnic groups who are identified with those peoples. Indigenous peoples are known in Canada as Aboriginal peoples, and in the United States as Native Americans...

 prehistorical settlement, these sites have been chosen for proximity to marine resource exploitation; for example, the Chumash settlement on the Morro Bay sandspit is one such location.

See also

• List of spits (landforms)
• Shoal
  Shoal
  Shoal, shoals or shoaling may mean:* Shoal, a sandbank or reef creating shallow water, especially where it forms a hazard to shipping* Shoal draught , of a boat with shallow draught which can pass over some shoals: see Draft...
  
  , a related landform
• Ria
  Ria
  A ria is a coastal inlet formed by the partial submergence of an unglaciated river valley. It is a drowned river valley that remains open to the sea. Typically, rias have a dendritic, treelike outline although they can be straight and without significant branches. This pattern is inherited from the...
  
  , often confused with spit: see Hurst Castle
  Hurst Castle
  Hurst Castle on the south coast of England is one of Henry VIII's Device Forts, built at the end of a long shingle barrier beach at the west end of the Solent to guard the approaches to Southampton. Hurst Castle was sited at the narrow entrance to the Solent where the ebb and flow of the tides...
  
  .