A karst spring or karstic spring is a spring (exsurgence, outflow of

groundwater Groundwater is the water present beneath Earth's surface in rock and Pore space in soil, soil pore spaces and in the fractures of stratum, rock formations. About 30 percent of all readily available fresh water in the world is groundwater. A unit ...

) that is part of a

karst Karst () is a topography formed from the dissolution of soluble carbonate rocks such as limestone and Dolomite (rock), dolomite. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. Ther ...

hydrological system.

Description

Because of their often conical or inverted bowl shape, karst springs are also known in German-speaking lands as a ''Topf'' ("pot") which is reflected in names such as Aachtopf (the source of the Radolfzeller Aach) or Blautopf (the source of the Blau river in Blaubeuren). Karst springs often have a very high yield or discharge rate, because they are often fed by underground drainage from a large

catchment basin A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, th ...

. Because the springs are usually the terminus of a cave drainage system at the place where a river cave reaches the Earth's surface, it is often possible to enter the caves from karst springs for exploration. Large karst springs are located in many parts of the world; the largest ones are believed to be in

Papua New Guinea Papua New Guinea, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean n ...

, with others located in

Mediterranean The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern ...

countries such as

Bosnia and Herzegovina Bosnia and Herzegovina, sometimes known as Bosnia-Herzegovina and informally as Bosnia, is a country in Southeast Europe. Situated on the Balkans, Balkan Peninsula, it borders Serbia to the east, Montenegro to the southeast, and Croatia to th ...

Croatia Croatia, officially the Republic of Croatia, is a country in Central Europe, Central and Southeast Europe, on the coast of the Adriatic Sea. It borders Slovenia to the northwest, Hungary to the northeast, Serbia to the east, Bosnia and Herze ...

Turkey Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armen ...

Slovenia Slovenia, officially the Republic of Slovenia, is a country in Central Europe. It borders Italy to the west, Austria to the north, Hungary to the northeast, Croatia to the south and southeast, and a short (46.6 km) coastline within the Adriati ...

, and

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

Types

An estavelle or inversac is a ground orifice which, depending on weather conditions and season, can serve either as a sink or as a source of fresh water. It is a type of

sinkhole A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are also known as shakeholes, and to openings where surface water ...

. A Vauclusian spring is a spring that originates from a shaft or a cave system, with the water surging upwards under relatively high pressure. It is named after the Fontaine de Vaucluse in southern France. Submarine karst springs, also known as , occur worldwide, and are most numerous in shallow waters of the

Mediterranean Sea The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...

. They can be considered to be karst springs which have become submerged by rising sea levels. For intermittent or rhythmic springs see below. They are part of another type of classification, which differentiates between perennial (with continuous flow), rhythmic, and temporary springs.

Hydrological features

A main feature of karst springs is that water is rapidly transported by caverns, so that there is minimal filtering of the water and little separation of different sediments. Groundwater emerges at the spring within a few days from precipitation. Storms, snowmelt, and general seasonal changes in rainfall have a very noticeable and rapid effect on karst springs. Many karst springs dry up during the driest part of the year, and are thus known as intermittent springs. Still others are dry most of the year round and only flow after heavy rain. Sources that only flow during wet years are often known in German as ''Hungerbrunnen'' ("hunger springs"), since folklore claimed a connection between the flow rate of a spring and poor crop yield in a wet year. This appears to be more of a culturally-related

superstition A superstition is any belief or practice considered by non-practitioners to be irrational or supernatural, attributed to fate or magic (supernatural), magic, perceived supernatural influence, or fear of that which is unknown. It is commonly app ...

, as scientific studies on various ''Hungerbrunnen'' have not confirmed such a relationship. An example is the ''Hungerbrunnen'' in the parish of Heuchlingen near Gerstetten. The properties of karst springs make them unsuitable for the supply of

drinking water Drinking water or potable water is water that is safe for ingestion, either when drunk directly in liquid form or consumed indirectly through food preparation. It is often (but not always) supplied through taps, in which case it is also calle ...

. Their uneven flow rate does not support a steady rate of consumption, especially in summer when there is lower discharge but higher demand. In addition, poor filtering and high

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to plastic deformation, such as an indentation (over an area) or a scratch (linear), induced mechanically either by Pressing (metalworking), pressing or abrasion ...

mean that the water quality is poor.

Cultural references

The French Realist painter

Gustave Courbet Jean Désiré Gustave Courbet ( ; ; ; 10 June 1819 – 31 December 1877) was a French painter who led the Realism movement in 19th-century French painting. Committed to painting only what he could see, he rejected academic convention and the ...

(1819–1877) painted a number of karst springs among many landscapes he depicted in the Jura region of eastern France.

Gallery

References

External links

Karst springs in Germany

The Hungerbrunnen in the Leinleiter valley
{{DEFAULTSORT:Karst Springs Springs (hydrology) Hydrogeology