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

groundwater Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated ...

) that is part of a karst 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 Aachtopf () is Germany's biggest karst spring, south of the western end of the Swabian Jura near the town of Aach. It produces an average of 8,500 litres per second. Most of the water stems from the River Danube where it disappears undergro ...

(the source of the

Radolfzeller Aach The Radolfzeller Aach (also known as Hegauer Aach) is a right or north tributary of the Rhine in the south of Baden-Württemberg (Germany). It is approximately 32 km long. Course The source of the river is the ''Aachtopf'' in Aach, the la ...

) or

Blautopf The Blautopf (German for ''Blue pot'') is a spring that serves as the source of the river Blau in the karst landscape on the Swabian Jura's southern edge. It is located in Blaubeuren, Alb-Donau-Kreis, Baden-Württemberg, Germany (approximately w ...

(the source of the Blau river in

Blaubeuren Blaubeuren () is a town in the district of Alb-Donau near Ulm in Baden-Württemberg, Germany. it had 11,963 inhabitants. Geography Geographical location The core city Blaubeuren lies at the foot of the Swabian Jura, west of Ulm. Neighborin ...

). 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 where 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, the ...

. Because the springs are usually the terminus of a cave drainage system at the place where a

river cave A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea c ...

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 (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Guinea ( tpi, Independen Stet bilong Papua Niugini; ho, Independen Stet bilong Papua Niu Gini), is a country i ...

, 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 north by Western Europe, Western and Southern Europe and Anatolia, on the south by North Africa ...

countries such as

Bosnia and Herzegovina Bosnia and Herzegovina ( sh, / , ), abbreviated BiH () or B&H, sometimes called Bosnia–Herzegovina and often known informally as Bosnia, is a country at the crossroads of south and southeast Europe, located in the Balkans. Bosnia and H ...

Croatia , image_flag = Flag of Croatia.svg , image_coat = Coat of arms of Croatia.svg , anthem = "Lijepa naša domovino"("Our Beautiful Homeland") , image_map = , map_caption = , capit ...

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a transcontinental country located mainly on the Anatolian Peninsula in Western Asia, with a small portion on the Balkan Peninsula in ...

Slovenia Slovenia ( ; sl, Slovenija ), officially the Republic of Slovenia (Slovene: , abbr.: ''RS''), is a country in Central Europe. It is bordered by Italy to the west, Austria to the north, Hungary to the northeast, Croatia to the southeast, an ...

, and

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

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 locally also known as ''vrtače'' and shakeholes, and to openi ...

. 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 north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...

. 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, 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 is water that is used in drink or food preparation; potable water is water that is safe to be used as drinking water. The amount of drinking water required to maintain good health varies, and depends on physical activity level, a ...

. 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 localized plastic deformation induced by either mechanical indentation or abrasion. In general, different materials differ in their hardness; for example hard ...

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 ...

(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