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Awash River

January 20, 2023

The Awash (sometimes spelled Awaash; Oromo: Awaash, Amharic: አዋሽ, Afar: We'ayot, Somali: Webiga Dir) is a major river of Ethiopia. Its course is entirely contained within the boundaries of Ethiopia and empties into a chain of interconnected lakes that begin with Lake Gargori and end with Lake Abbe (or Abhe Bad) on the border with Djibouti, some 100 kilometres (60 or 70 miles) from the head of the Gulf of Tadjoura. It is the principal stream of an endorheic drainage basin covering parts of the Amhara, Oromia and Somali Regions, as well as the southern half of the Afar Region.

Lower Valley of the Awash
UNESCO World Heritage Site
Awash River in 2005
LocationEthiopia
CriteriaCultural: (ii)(iii)(iv)
Reference10
Inscription1980 (4th Session)
Coordinates11°6′0.216″N 40°34′45.804″E / 11.10006000°N 40.57939000°E / 11.10006000; 40.57939000
Location of Awash River in Ethiopia

The Awash Valley (and especially the Middle Awash) is internationally famous for its high density of hominin fossils, offering unparalleled insight into the early evolution of humans.[1] "Lucy", one of the most famous early hominin fossils, was discovered in the lower Awash Valley.[1] For its paleontological and anthropological importance, the lower valley of the Awash was inscribed on the UNESCO World Heritage List in 1980.[1]

Overview

 
Map of the Awash drainage basin

The Awash rises south of Mount Warqe, west of Addis Ababa in the woreda of Dandi, close to the town of Ginchi, West Shewa Zone, Oromia. After entering the bottom of the Great Rift Valley, the Awash flows south to loop around Mount Zuqualla in an easterly then northeasterly direction, before entering Koka Reservoir. There, water is used for the irrigation of sugar cane plantations. Downstream, the Awash passes the city of Adama and the Awash National Park. It is then joined on its left bank by its chief affluent, the Germama (or Kasam) River, before turning northeast at approximately 11° N 40° 30' E as far north as 12° before turning completely east to reach lake Gargori.

According to materials published by the Ethiopian Central Statistical Agency, the Awash River is 1200 kilometers long.[2] Frank Richardson Cana, in the Encyclopædia Britannica Eleventh Edition article Abyssinia, describes its middle portion as "a copious stream nearly 200 feet [61 meters] wide and 4 feet [1.2 meters] deep in the dry season, and during the floods rising 50 or 60 feet [15 or 18 meters] above low-water mark, thus inundating the plains for many miles along both its banks."[3]

Other tributaries of the Awash include (in order upstream): the Logiya, Mille, Borkana, Ataye, Hawadi, Kabenna and Durkham Rivers. Towns and cities along its course include Metehara, Awash, Gewane and Asaita.

Paleontology

Main article: Middle Awash

Humans have lived in the valley of the Awash almost since the beginning of the species. Numerous pre-human hominid remains have been found in the Middle Awash.[4] The remains found in the Awash Valley date from the late Miocene, Pliocene, and early Pleistocene (roughly 5.6-2.5 million years ago), and include fossils of many Australopithecines, including "Lucy", the most famous individual Australopithecus.[4][1] Other extinct hominids discovered at the site include Homo erectus and Ardipithecus.

History

 
Awash River in the Awash National Park

The valley of the Awash from about 9° N downstream is the traditional home of the Afar people and Issa people.[5] The valley of the Awash have been included as part of the Fatagar, Ifat, and Shewa.[6]

According to Huntingford, in the 16th century the Awash river was called the great Dir river and lay in the country of the Muslims.[7]

 
The Koka Dam before it was completed 1960

The first European to trace the course of the Awash to its end in the Aussa oasis was Wilfred Thesiger in 1933/1934, who started at the city of Awash, followed the river's course to its final end in Lake Abhebad, and continued his expedition east to Tadjoura. (Although the explorer L.M. Nesbitt had followed parts of the course of the Awash in 1928, he turned away from the river at Asaita and proceeded north through the Afar Depression to the Red Sea.[8])

In 1960, the Koka Dam was completed across the Awash River at a point around 75 kilometers from Addis Ababa. With its opening, it became a major source of hydroelectric power in the area. The resulting freshwater lake, Lake Gelila (also known as the Koka Reservoir), has an area of about 180 square kilometers. Both lake and dam are threatened by increasing sedimentation.

The Awash International Bank is named for the Awash River.

Climate

The climate of the Awash River Basin is mostly influenced by the movement of the intertropical convergence zone (ITCZ). During its movement northwards in March/April and its retreat southwards, ITCZ creates two rainy seasons, a shorter one around March ('Belg'), and a longer one between June and September ('Kiremt'), which partly fall into one longer rainy season. The rain-season tends to be bimodal towards eastern Ethiopia and almost unimodal towards western Ethiopia. The time between October and March is a dry season, called 'Bega'.[9] Semi-arid to arid conditions prevail in the Rift Valley. In contrast, the highlands partly receive more than 1600 mm of rainfall in ca. six months per year.[10]

Hydrology

Groundwater recharge varies between values exceeding 350 mm per year in the upper highlands and no recharge at the bottom of the rift valley.[10][11] Groundwater is predominantly recharged at the escarpments and highlands above 1900 m a.s.l.,[12] where annual rainfall is higher than 1000 mm.[11] Localized small-scale recharge is also supposed to occur at the flanks of the rift valley volcanoes.[12] Artificial groundwater recharge takes further place at irrigated plantations at the rift valley.[12] Recharge from river channel losses and via infiltration from lakes plays a role in the Main Ethiopian Rift (MER) and in southern Afar.[11]

Ecology

Most of the Awash Basin is part of the Ethiopian montane forests ecoregion. At high altitudes the Ethiopian montane grasslands and woodlands and Ethiopian montane moorlands predominate. The Somali Acacia–Commiphora bushlands and thickets ecoregion occupies low elevations in the Rift.[13]

The basin's vegetation has a strong anthropogenic impact.[10] All over the upper and central Awash Basin, remains of different savanna types are still clearly visible. They range from thorn savannas in the lower rift, bush, grass and open savannas above 800 m and woody savannas on the escarpments and the highlands. Forestry hardly exists inside the Awash River Basin, with a few exceptions of small eucalyptus plantations. Outside of Awash National Park the open and woody savannas have been almost completely cultivated with crops. This especially accounts for all escarpment terraces.[14] Thereby the scattered tree cover remained similar to the primary state of the savannas, while the grass layer has been replaced by crops. Only highest altitudes still show connected woodlands. Partly reforestation was carried out on not cultivable altitudes with secondary coniferous forests. The cultivated crops are (endemic) teff, maize, sorghum, beans and vegetables.[14] Pastures hardly exist where agriculture is possible. The cattle graze on field edges and waysides and on steep escarpments. This is one major reason for erosion, because vegetation cover is partly destroyed. Stubble-grazing is a common practice in the Awash Basin.[15]

Fauna

The lower Awash valley is one of the last wildlife preserves for the African wild ass. The mammal is now extinct in Yangudi Rassa National Park, but still found in the adjacent Mille-Serdo Wildlife Reserve.[16] Other large animals native to the area include Beisa Oryx, Soemmering's gazelle, Dorcas gazelle, gerenuk and Grevy's zebra. Crocodiles also flourish within the river.

See also

References

  1. ^ a b c d "Lower Valley of the Awash". UNESCO World Heritage Site. United Nations Educational, Scientific, and Cultural Organization. Retrieved 18 September 2021.
  2. ^ "Climate, 2008 National Statistics (Abstract)", Table A.1. Central Statistical Agency website (accessed 26 December 2009)
  3. ^   One or more of the preceding sentences incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Abyssinia". Encyclopædia Britannica. Vol. 1 (11th ed.). Cambridge University Press. p. 84.
  4. ^ a b Haile-Selassie, Yohannes (2001-07-12). "Late Miocene hominids from the Middle Awash, Ethiopia". Nature. 412 (6843): 178–181. Bibcode:2001Natur.412..178H. doi:10.1038/35084063. ISSN 0028-0836. PMID 11449272. S2CID 4432082.
  5. ^ Markakis, John (2003). "Anatomy of a Conflict: Afar & Ise Ethiopia". Review of African Political Economy. 30 (97): 445–453. doi:10.1080/03056244.2003.9659777. ISSN 0305-6244. JSTOR 4006987. S2CID 153511308.
  6. ^ Richard Pankhurst, The Ethiopian Borderlands (Lawrenceville: Red Sea Press, 1997), p. 61
  7. ^ ʻArabfaqīh, Shihāb al-Dīn Aḥmad ibn ʻAbd al-Qādir (2003-01-01). The conquest of Abyssinia: 16th century. Hollywood: Tsehai Publishers & Distributors. p. 124. ISBN 978-0-9723172-6-9.
  8. ^ As related in his memoirs, Hell-Hole of Creation: The Exploration of Abyssinian Danakil (New York: Alfred A. Knopf, 1935)
  9. ^ Seleshi, Yilma; Zanke, Ulrich (2004-06-30). "Recent changes in rainfall and rainy days in Ethiopia". International Journal of Climatology. 24 (8): 973–983. Bibcode:2004IJCli..24..973S. doi:10.1002/joc.1052. ISSN 1097-0088.
  10. ^ a b c Knoche, Malte; Fischer, Christian; Pohl, Eric; Krause, Peter; Merz, Ralf (2014). "Combined uncertainty of hydrological model complexity and satellite-based forcing data evaluated in two data-scarce semi-arid catchments in Ethiopia". Journal of Hydrology. 519: 2049–2066. Bibcode:2014JHyd..519.2049K. doi:10.1016/j.jhydrol.2014.10.003.
  11. ^ a b c Ayenew, Tenalem; Demlie, Molla; Wohnlich, Stefan (2008). "Hydrogeological framework and occurrence of groundwater in the Ethiopian aquifers". Journal of African Earth Sciences. 52 (3): 97–113. Bibcode:2008JAfES..52...97A. doi:10.1016/j.jafrearsci.2008.06.006.
  12. ^ a b c Bretzler, Anja; Osenbrück, Karsten; Gloaguen, Richard; Ruprecht, Janina S.; Kebede, Seifu; Stadler, Susanne (2011). "Groundwater origin and flow dynamics in active rift systems – A multi-isotope approach in the Main Ethiopian Rift". Journal of Hydrology. 402 (3–4): 274–289. Bibcode:2011JHyd..402..274B. doi:10.1016/j.jhydrol.2011.03.022.
  13. ^ "The ecozones of the world. The ecological division of the geosphere". ResearchGate. Retrieved 2017-10-21.
  14. ^ a b Knoche, M. (2011): Hydrological Modelling of the Upper Awash Catchment (Main Ethiopian Rift). Master thesis, Technische Universität Freiberg, 2011, Freiberg, Germany
  15. ^ Nyssen, Jan; Poesen, Jean; Moeyersons, Jan; Haile, Mitiku; Deckers, Jozef (2008-04-30). "Dynamics of soil erosion rates and controlling factors in the Northern Ethiopian Highlands – towards a sediment budget". Earth Surface Processes and Landforms. 33 (5): 695–711. Bibcode:2008ESPL...33..695N. doi:10.1002/esp.1569. hdl:1854/LU-416185. ISSN 1096-9837.
  16. ^ Moehlman, P.D., Yohannes, H., Teclai, R. & Kebede, F. 2008. Equus Africanus. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.1. <www.iucnredlist.org>. Downloaded on 28 September 2011.

External links

  •   Media related to Awash River at Wikimedia Commons
  • The Middle Awash Project website

Further reading

  • Zewdu Tememew Molla, "Dam Safety Evaluation on Koka Dam, Ethiopia". M.Sc. thesis, 2005. abstract

  This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Abyssinia". Encyclopædia Britannica (11th ed.). Cambridge University Press. Coordinates: 11°06′00″N 40°34′46″E / 11.10000°N 40.57944°E / 11.10000; 40.57944

January 20, 2023
awash, river, awash, sometimes, spelled, awaash, oromo, awaash, amharic, አዋሽ, afar, ayot, somali, webiga, major, river, ethiopia, course, entirely, contained, within, boundaries, ethiopia, empties, into, chain, interconnected, lakes, that, begin, with, lake, g. The Awash sometimes spelled Awaash Oromo Awaash Amharic አዋሽ Afar We ayot Somali Webiga Dir is a major river of Ethiopia Its course is entirely contained within the boundaries of Ethiopia and empties into a chain of interconnected lakes that begin with Lake Gargori and end with Lake Abbe or Abhe Bad on the border with Djibouti some 100 kilometres 60 or 70 miles from the head of the Gulf of Tadjoura It is the principal stream of an endorheic drainage basin covering parts of the Amhara Oromia and Somali Regions as well as the southern half of the Afar Region Lower Valley of the AwashUNESCO World Heritage SiteAwash River in 2005LocationEthiopiaCriteriaCultural ii iii iv Reference10Inscription1980 4th Session Coordinates11 6 0 216 N 40 34 45 804 E 11 10006000 N 40 57939000 E 11 10006000 40 57939000Location of Awash River in EthiopiaThe Awash Valley and especially the Middle Awash is internationally famous for its high density of hominin fossils offering unparalleled insight into the early evolution of humans 1 Lucy one of the most famous early hominin fossils was discovered in the lower Awash Valley 1 For its paleontological and anthropological importance the lower valley of the Awash was inscribed on the UNESCO World Heritage List in 1980 1 Contents 1 Overview 2 Paleontology 3 History 4 Climate 5 Hydrology 6 Ecology 7 Fauna 8 See also 9 References 10 External links 11 Further readingOverview Edit Map of the Awash drainage basin The Awash rises south of Mount Warqe west of Addis Ababa in the woreda of Dandi close to the town of Ginchi West Shewa Zone Oromia After entering the bottom of the Great Rift Valley the Awash flows south to loop around Mount Zuqualla in an easterly then northeasterly direction before entering Koka Reservoir There water is used for the irrigation of sugar cane plantations Downstream the Awash passes the city of Adama and the Awash National Park It is then joined on its left bank by its chief affluent the Germama or Kasam River before turning northeast at approximately 11 N 40 30 E as far north as 12 before turning completely east to reach lake Gargori According to materials published by the Ethiopian Central Statistical Agency the Awash River is 1200 kilometers long 2 Frank Richardson Cana in the Encyclopaedia Britannica Eleventh Edition article Abyssinia describes its middle portion as a copious stream nearly 200 feet 61 meters wide and 4 feet 1 2 meters deep in the dry season and during the floods rising 50 or 60 feet 15 or 18 meters above low water mark thus inundating the plains for many miles along both its banks 3 Other tributaries of the Awash include in order upstream the Logiya Mille Borkana Ataye Hawadi Kabenna and Durkham Rivers Towns and cities along its course include Metehara Awash Gewane and Asaita Paleontology EditMain article Middle Awash Humans have lived in the valley of the Awash almost since the beginning of the species Numerous pre human hominid remains have been found in the Middle Awash 4 The remains found in the Awash Valley date from the late Miocene Pliocene and early Pleistocene roughly 5 6 2 5 million years ago and include fossils of many Australopithecines including Lucy the most famous individual Australopithecus 4 1 Other extinct hominids discovered at the site include Homo erectus and Ardipithecus History Edit Awash River in the Awash National Park The valley of the Awash from about 9 N downstream is the traditional home of the Afar people and Issa people 5 The valley of the Awash have been included as part of the Fatagar Ifat and Shewa 6 According to Huntingford in the 16th century the Awash river was called the great Dir river and lay in the country of the Muslims 7 The Koka Dam before it was completed 1960 The first European to trace the course of the Awash to its end in the Aussa oasis was Wilfred Thesiger in 1933 1934 who started at the city of Awash followed the river s course to its final end in Lake Abhebad and continued his expedition east to Tadjoura Although the explorer L M Nesbitt had followed parts of the course of the Awash in 1928 he turned away from the river at Asaita and proceeded north through the Afar Depression to the Red Sea 8 In 1960 the Koka Dam was completed across the Awash River at a point around 75 kilometers from Addis Ababa With its opening it became a major source of hydroelectric power in the area The resulting freshwater lake Lake Gelila also known as the Koka Reservoir has an area of about 180 square kilometers Both lake and dam are threatened by increasing sedimentation The Awash International Bank is named for the Awash River Climate EditThe climate of the Awash River Basin is mostly influenced by the movement of the intertropical convergence zone ITCZ During its movement northwards in March April and its retreat southwards ITCZ creates two rainy seasons a shorter one around March Belg and a longer one between June and September Kiremt which partly fall into one longer rainy season The rain season tends to be bimodal towards eastern Ethiopia and almost unimodal towards western Ethiopia The time between October and March is a dry season called Bega 9 Semi arid to arid conditions prevail in the Rift Valley In contrast the highlands partly receive more than 1600 mm of rainfall in ca six months per year 10 Hydrology EditGroundwater recharge varies between values exceeding 350 mm per year in the upper highlands and no recharge at the bottom of the rift valley 10 11 Groundwater is predominantly recharged at the escarpments and highlands above 1900 m a s l 12 where annual rainfall is higher than 1000 mm 11 Localized small scale recharge is also supposed to occur at the flanks of the rift valley volcanoes 12 Artificial groundwater recharge takes further place at irrigated plantations at the rift valley 12 Recharge from river channel losses and via infiltration from lakes plays a role in the Main Ethiopian Rift MER and in southern Afar 11 Ecology EditMost of the Awash Basin is part of the Ethiopian montane forests ecoregion At high altitudes the Ethiopian montane grasslands and woodlands and Ethiopian montane moorlands predominate The Somali Acacia Commiphora bushlands and thickets ecoregion occupies low elevations in the Rift 13 The basin s vegetation has a strong anthropogenic impact 10 All over the upper and central Awash Basin remains of different savanna types are still clearly visible They range from thorn savannas in the lower rift bush grass and open savannas above 800 m and woody savannas on the escarpments and the highlands Forestry hardly exists inside the Awash River Basin with a few exceptions of small eucalyptus plantations Outside of Awash National Park the open and woody savannas have been almost completely cultivated with crops This especially accounts for all escarpment terraces 14 Thereby the scattered tree cover remained similar to the primary state of the savannas while the grass layer has been replaced by crops Only highest altitudes still show connected woodlands Partly reforestation was carried out on not cultivable altitudes with secondary coniferous forests The cultivated crops are endemic teff maize sorghum beans and vegetables 14 Pastures hardly exist where agriculture is possible The cattle graze on field edges and waysides and on steep escarpments This is one major reason for erosion because vegetation cover is partly destroyed Stubble grazing is a common practice in the Awash Basin 15 Fauna EditThe lower Awash valley is one of the last wildlife preserves for the African wild ass The mammal is now extinct in Yangudi Rassa National Park but still found in the adjacent Mille Serdo Wildlife Reserve 16 Other large animals native to the area include Beisa Oryx Soemmering s gazelle Dorcas gazelle gerenuk and Grevy s zebra Crocodiles also flourish within the river See also EditList of rivers of Ethiopia List of fossil sites with link directory List of hominina hominid fossils with images List of World Heritage Sites in EthiopiaReferences Edit a b c d Lower Valley of the Awash UNESCO World Heritage Site United Nations Educational Scientific and Cultural Organization Retrieved 18 September 2021 Climate 2008 National Statistics Abstract Table A 1 Central Statistical Agency website accessed 26 December 2009 One or more of the preceding sentences incorporates text from a publication now in the public domain Chisholm Hugh ed 1911 Abyssinia Encyclopaedia Britannica Vol 1 11th ed Cambridge University Press p 84 a b Haile Selassie Yohannes 2001 07 12 Late Miocene hominids from the Middle Awash Ethiopia Nature 412 6843 178 181 Bibcode 2001Natur 412 178H doi 10 1038 35084063 ISSN 0028 0836 PMID 11449272 S2CID 4432082 Markakis John 2003 Anatomy of a Conflict Afar amp Ise Ethiopia Review of African Political Economy 30 97 445 453 doi 10 1080 03056244 2003 9659777 ISSN 0305 6244 JSTOR 4006987 S2CID 153511308 Richard Pankhurst The Ethiopian Borderlands Lawrenceville Red Sea Press 1997 p 61 ʻArabfaqih Shihab al Din Aḥmad ibn ʻAbd al Qadir 2003 01 01 The conquest of Abyssinia 16th century Hollywood Tsehai Publishers amp Distributors p 124 ISBN 978 0 9723172 6 9 As related in his memoirs Hell Hole of Creation The Exploration of Abyssinian Danakil New York Alfred A Knopf 1935 Seleshi Yilma Zanke Ulrich 2004 06 30 Recent changes in rainfall and rainy days in Ethiopia International Journal of Climatology 24 8 973 983 Bibcode 2004IJCli 24 973S doi 10 1002 joc 1052 ISSN 1097 0088 a b c Knoche Malte Fischer Christian Pohl Eric Krause Peter Merz Ralf 2014 Combined uncertainty of hydrological model complexity and satellite based forcing data evaluated in two data scarce semi arid catchments in Ethiopia Journal of Hydrology 519 2049 2066 Bibcode 2014JHyd 519 2049K doi 10 1016 j jhydrol 2014 10 003 a b c Ayenew Tenalem Demlie Molla Wohnlich Stefan 2008 Hydrogeological framework and occurrence of groundwater in the Ethiopian aquifers Journal of African Earth Sciences 52 3 97 113 Bibcode 2008JAfES 52 97A doi 10 1016 j jafrearsci 2008 06 006 a b c Bretzler Anja Osenbruck Karsten Gloaguen Richard Ruprecht Janina S Kebede Seifu Stadler Susanne 2011 Groundwater origin and flow dynamics in active rift systems A multi isotope approach in the Main Ethiopian Rift Journal of Hydrology 402 3 4 274 289 Bibcode 2011JHyd 402 274B doi 10 1016 j jhydrol 2011 03 022 The ecozones of the world The ecological division of the geosphere ResearchGate Retrieved 2017 10 21 a b Knoche M 2011 Hydrological Modelling of the Upper Awash Catchment Main Ethiopian Rift Master thesis Technische Universitat Freiberg 2011 Freiberg Germany Nyssen Jan Poesen Jean Moeyersons Jan Haile Mitiku Deckers Jozef 2008 04 30 Dynamics of soil erosion rates and controlling factors in the Northern Ethiopian Highlands towards a sediment budget Earth Surface Processes and Landforms 33 5 695 711 Bibcode 2008ESPL 33 695N doi 10 1002 esp 1569 hdl 1854 LU 416185 ISSN 1096 9837 Moehlman P D Yohannes H Teclai R amp Kebede F 2008 Equus Africanus In IUCN 2011 IUCN Red List of Threatened Species Version 2011 1 lt www iucnredlist org gt Downloaded on 28 September 2011 External links Edit Media related to Awash River at Wikimedia Commons The Middle Awash Project websiteFurther reading EditZewdu Tememew Molla Dam Safety Evaluation on Koka Dam Ethiopia M Sc thesis 2005 abstract This article incorporates text from a publication now in the public domain Chisholm Hugh ed 1911 Abyssinia Encyclopaedia Britannica 11th ed Cambridge University Press Coordinates 11 06 00 N 40 34 46 E 11 10000 N 40 57944 E 11 10000 40 57944 Retrieved from https en wikipedia org w index php title Awash River amp oldid 1092615705, wikipedia, wiki, book, books, library,

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