Endorheic
Endorheic ( Greek ἔνδον endon 'inside'; ῥεῖν rhein 'flow') is the term used in geosciences to refer to catchment areas that have no drainage into the sea. The opposite term is exorheic (drainage into the sea). Some hydrologists also differentiate between arheic areas, which are those that only drain underground, mostly karst areas.
Endorheic pelvis
Endorheic basins are the areas of the earth that do not drain into the oceans, but form independent water systems . These areas comprise about 13 percent of the global land surface. The end water is called endorheic water . Despite the large catchment area, the runoff of endorheic rivers only contributes 1.9 percent to global runoff, this is due to the fact that the majority of these are arid areas.
The largest endorheic area in the world is the Central Asian Basin, with the catchment area of the Caspian Sea , the Aral Sea and the Balkhash Sea ; Eastern Europe has a share in this via the catchment area of the Volga , which drains to the Caspian Sea, it makes up about 19 percent of the area of the continent. The catchment area of the Caspian Sea alone, with 3 million square kilometers, makes up around 2 percent of the global land surface, that of the Aral Sea another 2 million. Other significant endorheic rivers in it include the Ili , Tarim , Syrdarya , Amudarya and Urals .
The largest endorheic (and arheic) area in North America is the Great Basin in Nevada and Utah with foothills to California , Oregon and Idaho , about half of the endorheic area of this continent alone (about 10 percent in total). Overall, however, the catchment areas of endorheic rivers in North America make up the smallest share of all continents at only around two percent; the rest of the basins are arheic. In Australia, the largest endorheic area is the Lake Eyre Depression, at 1.14 million square kilometers, about one sixth of the continent. The largest endorheic area in South America is the catchment area of Lake Titicaca .
Endorheic rivers
As endorheischer River , a river is designated according to who does not drained into the sea, but in a endorheisches Still Waters (Examples: Volga to the Caspian Sea, Jordan to the Dead Sea), or into a drain basin without pours (examples: inland delta of the Okavango , Onyx to one of the McMurdo Dry Valleys ). The term is to be distinguished from the river shrinkage, in which a flowing water completely loses its course without flowing into a depression - a river can only shrink because in an arid climate more water evaporates than flows in, or stops flowing (example : Wadis of the Sahara), or if the soil is permeable, it seeps away ( infiltration stretch , e.g. alluvial cones of the southern Alpine rivers into the Po Valley) or is swallowed up ( ponors of the karst waters ).
Endorheic Lakes
An endorheic lake is a lake with no outflow, which only loses the water flowing in through the tributaries through evaporation. Endorheic lakes are often salt lakes .
Other typical endorheic waters are crater lakes and cirque lakes in non-arid zones, which can also temporarily overflow during heavy rain or when the snow melts.
Drain
The term runoff in hydrology implies that it is superficial runoff - groundwater exchange between an endorheic area and neighboring areas is possible. However, the term 'endorheic' does not include continuations as an underground watercourse (still water without drainage, shrinkage or swallowing ). The main characteristic is that the water primarily only evaporates - high salinity may develop in lakes ( Dead Sea , Great Salt Lake , but not necessarily: Neusiedlersee ). In the Aral Sea or Lake Chad , the evaporation is so strong that it begins to disappear completely due to excessive water abstraction. An example of an intermittent body of water is the Etosha Pan , a former salt lake comparable to the two aforementioned, today a salt desert that becomes a shallow lake after exceptional events.
Shallow basins of endorheic drainage systems (pans) can overflow in strong water, then episodic runoffs occur (example: Okavango basin, under certain circumstances drains into the Makgadikgadi pan 300 km away ).
See also
literature
- Matthias Schaefer: Dictionary of Ecology. 5th, revised and expanded edition. Spektrum Akademischer Verlag, Heidelberg 2012, ISBN 978-3-8274-2561-4 , p. 75 ( full text in the Google book search)
Web links
Individual evidence
- ↑ a b C. J. Vorosmarty, Balazs M. Fekete, M. Meybeck, Richard B. Lammers: Global system of rivers: Its role in organizing continental land mass and defining land-to-ocean linkages. In: Global Biogeochemical Cycles. 14 (2), 2000, pp. 599-621. doi: 10.1029 / 1999GB900092
- ^ Hans H. Dürr, Goulven G. Laruelle, Cheryl M. van Kempen, Caroline P. Slomp, Michel Meybeck, Hans Middelkoop: Worldwide Typology of Nearshore Coastal Systems: Defining the Estuarine Filter of River Inputs to the Oceans. In: Estuaries and Coasts. 34, 2011, pp. 441-458. doi: 10.1007 / s12237-011-9381-y
- ↑ a b Vadim Yapiyev, Zhanay Sagintayev, Vassilis J. Inglezakis, Kanat Samarkhanov, Anne Verhoef: Essentials of Endorheic Basins and Lakes: A Review in the Context of Current and Future Water Resource Management and Mitigation Activities in Central Asia. In: Water. 9, 2017, article 798. doi: 10.3390 / w9100798
- ^ World Meteorological Organization: International Glossary of Hydrology. WMO-No. 385. World Meteorological Organization and United Nations Educational, Scientific and Cultural Organization, Geneva 2012, ISBN 978-92-3-001154-3 .