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Sudd

From Wikipedia
Sudd
swamp
CountrySouth Sudan Edit
Coordinate location8°0′0″N 31°0′0″E Edit
Heritage designationRamsar site, Tentative World Heritage Site Edit
World Heritage criteria(v), (vii), (ix), (x) Edit
Map
Satellite image of de swamp around de time of de wet season

De Sudd (Arabic: السد, romanized: as-Sudd, Nuer: Baki̱ec, Dinka: Toc) be a vast swamp for South Sudan insyd, wey de White Nile ein Baḥr al-Jabal section form am. Dem derive de Arabic word sudd from sadd (سد), wey dey mean "barrier"[1] anaa "obstruction".[2] De term "the sudd" cam to refer to any large solid floating vegetation island anaa mat. De area wey de swamp dey cover be one of de world ein largest wetlands den de largest freshwater wetland for de Nile Basin insyd.

Give many centuries de swamp, den especially ein thicket of vegetation, prove an impenetrable barrier to navigation along de Nile. De ancient Egyptians fail to penetrate de Sudd den dey reach de areas south of am.[3] For AD 61 insyd, a party of Roman soldiers wey de Emperor Nero send am proceed up de White Nile but e no dey able to get beyond de Sudd, wey mark de limit of Roman penetration into equatorial Africa.[4] Give de same reasons for later times insyd, de search give de source of de Nile be particularly difficult; e eventually involve ovaland expeditions from de central African coast, so as to avoid having to travel thru de Sudd.

For 2019 insyd, a study suggest say water flows wey e increase into de Sudd go dey partly cause up to a third of de whole West African rise for atmospheric methane levels insyd ova de previous decade.[5][6]

Location

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De Sudd dey stretch from Mongalla to just outside de Sobat River confluence plus de White Nile just upstream of Malakal as well as westwards along de Bahr el Ghazal. De shallow den flat inland delta dey lie between 5.5 den 9.5 degrees latitude north den dey cover an area of 500 kilometres (310 mi) south to north den 200 kilometres (120 mi) east to west between Mongalla for de south den Malakal insyd for de north insyd.

Ein size be highly variable, wey dey average ova 30,000 square kilometres (12,000 sq mi). During de wet season e go fi extend to ova 130,000 square kilometres (50,000 sq mi) wey dey comprise 21% of de country, wey e depend for de inflowing waters top, plus de discharge from Lake Victoria wey aleady be de main control factor of flood levels den area inundation. Since de Sudd area dey consist of various meandering channels, lagoons, reed den papyrus fields den dey lose half of ein inflowing water thru evapotranspiration for de permanent den seasonal floodplains insyd, de complex hydrology get many primary den secondary effects.[7] A major feature of de area be de incomplete Jonglei Canal, wey dem plan am to bypass waters from de Sudd to avoid evaporation losses den increase de amount of water wey dem discharge at de outlet of de Sudd.

From 1961 to 1963, a great increase for de flooded area insyd occur wen de level of Lake Victoria rise, den de outflow increase. Dem relate de total area of de Sudd to de amount of water wey dey reach Bor from de Albert Nile den from torrents anaa seasonal watercourses dat fi add substantial amounts to de flow for de upstream end of de Sudd insyd. During de 1960s increase for Lake Victoria discharge insyd, wey dey flow at Mongalla roughly doubled, de flows at Malakal at de northern end of de swamps increase by 1.5 times de previous average flow. As a consequence of dem high flows, de areas of permanent swamp den seasonal floodplains wey dem take togeda, increase to 2.5 times demma former size. De swamps increase de most, den de seasonal floodplain be 1.5 times ein previous size.[8]

From de southern inflow of de Bahr al Jabal ("Sea of de Mountain") at Mongalla, de riverbed wey dem define successively dey widen into a floodplain, wey de waters flow for meandering river stretches insyd den various channels den lagoons thruout de dry season. Plus rising water levels e dey expand ova de semi-flooded grasslands during de flood season.

Slightly downstream of Bor, de Bahr el Zeraf ("Sea of de Giraffes") river dey branch off de Bahr al Jabal to de east, wey e divert part of de flow, den again dey join de Bahr al Jabal just before e reach Malakal. During de course of ein flow, de Bahr al Jabal dey pass Lake No, wey de Bahr el Ghazal ("Sea of de Gazelles") dey connect to de Bahr al Jabal, wey e contribute an inflow plus seasonal variation. At Malakal, de Sobat River dey join into de system. De flows wey dem combine then dey stream to de north as de White Nile for a defined bed insyd, wey e join plus de Blue Nile waters at Khartoum to form de main Nile.

Dem designate Sudd as a Ramsar Wetland of International Importance for 2006 insyd. Dem designate an area of 57,000 square kilometres (22,000 sq mi).

Climate

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Hydrologically de Sudd dey play an important role for dey store floodwaters insyd den dey trap sediments from de Bahr al Jabal. Roughly 55% of water wey dey enter de area, dem lose am to evaporation.[9] Water levels dey fluctuate by up to 1.5 metres, wey e depend for de intensity of seasonal flooding top.[8] De region dey receive less rainfall (typically between 55 den 65 centimetres per year) dan neighbouring areas at de same latitude. Orographic lifting for de eastern den western sides of de Sudd top dey contribute to dat condition.[10]

Geomorphology

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Dem define de morphology of de area by de channel den lagoon system of de permanent Sudd swamps, de adjacent flood plains, den de surrounding flat terrain. De Bahr al Jabal dey run to de north-northwest den therefore for an angle insyd to de gradient of de floodplain, wey dey slope down to de north, while north of Juba de river dey flow for an incised trough insyd. De banks of dis trough dey decrease for height insyd from south to north plus de Bahr al Jabal wey dey approach Bor den dey end for de Sudd flood plain insyd just north of Bor for de eastern bank top den towards Shambe for de western bank top. For de southern part insyd, de river dey meander from side to side for de restraining trough insyd for one anaa more channels insyd, but further north dem no dey limit de swamp by higher ground den de system of river channels dey becam increasingly complex. De characteristics of de river plus ein network of channels den lagoons be distinguishable for satellite imagery den digital elevation models insyd.

Dem define de geology of de area by heavy clay soils, highly impermeable plus a top layer of "black cotton" vertisol of approximately 500 mm for average top. Dem find sandy soils only at depths of approximately 30 metres (98 ft) den below, as well drilling profiles determine am.[11] Dis dey indicate a very limited groundwater influence for de area ein hydrology top.

Population

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Nuer den Dinka pastoralists dey use de Sudd den de surrounding areas extensively. Livestock den rain-fed agriculture be de dominant means of support give de largely rural population give wey de seasonal flooded grasslands along de Sudd dey provide valuable grazing lands.[9]

Vegetation den ecosystem

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Dem fi classify vegetation cover of de area generally for five categories insyd wey dey depend for de elevation of de area top above river flood level: de lakes den rivers, de plant life of de swamp wey dey float, river-flooded grasslands (Toic), rain-flooded grasslands, den wooded grasslands for de fringes top. Local populations already cultivate grassland den woodland areas.

De density of de grasslands along de Sudd dey change plus de season, plus tall grass for de rainy season insyd den short dry grass for de dry season insyd, wen frequent fires sanso dey occur. Dem mostly ovagrow fluvial area plus vegetation, plus sam main de side channels as well as lagoons of open water. Dem describe de vegetation distribution for further detail insyd for Sutcliffe (1974) den Petersen (2007) insyd. De main species be:

  • Phragmites communis (shallow flooded, buried roots)
  • Echinochloa pyramidalis (shallow flooded, buried roots)
  • Oryza barthii (shallow flooded, buried roots)
  • Echinochloa stagnina (deep flooded, superficial/floating roots)
  • Vossia cuspidata (deep flooded, superficial/floating roots)
  • Cyperus papyrus (deep flooded, superficial/floating roots)
  • Typha domingensis

Dem anchor first three species so dem limit demma distribution to de depth of flooding. Give de last species demma root system dey need to be permanently for water anaa saturated soil insyd, wey be a good indicator of flood patterns. P. communis, E. pyramidalis den O. barthii for example dey dominate only for areas insyd wey de depth of flooding no dey exceed 130 cm ova a period of ten years anaa 118 cm give one month for de year insyd.

Floating vegetation of C. papyrus cause blockages for de Sudd swamps insyd for a number of occasions top between 1879 den 1900, wen inscrease flooding tear out plants. C. papyrus dey need saturated conditions den fi tolerate flooding dat no dey more dan 150 cm deep.[12]

Wen de matted vegetation dey break free of ein moorings, e dey form floating islands of vegetation up to 30 km for length insyd. Such islands, for varying stages of decomposition insyd, eventually dey break up.

Historically, de fully floating Nile cabbage (Pistia stratiotes) be an important plant for de Sudd insyd, but dem already largely replace am de invasive water hyacinth (Eichhornia crassipes).[13] De sluggish waters be host to a large population of mosquitoes den parasites dat dey cause waterborne diseases.

Fauna

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Dey include several diverse aquatic habitats like swamps, lakes, channels den floodplains, de Sudd be rich for fish insyd. Dem already record sam 70 species, den dis dey mostly involve fish dat dem find for much of de Nile system insyd such as marbled lungfish, Senegal bichir, African arowana, Mormyrus caschive, Nile carp, Nile tilapia, mango tilapia, redbelly tilapia, Nile perch, Distichodus rostratus, elongate tigerfish, African tetras, African sharptooth catfish, Synodontis frontosus, S. schall den odas.[13] Among de few endemics of de Sudd system be Clarias engelseni, Enteromius yeiensis, Nothobranchius nubaensis, N. virgatus den two apparently undescribed species of Enteromius, den de fish fauna for significant sections insyd still dem no properly study am.[14]

Dem find ova 400 species of bird for de Sudd insyd, wey dey include shoebills (a stronghold give de species plus several thousand individuals), great white pelicans, den black crowned cranes. De Sudd dey provide food den water to large populations of migrating birds. As de surrounding landscape be a large swath of dry Sahel across Africa, de swamp sanso be a haven give migrating mammals, especially antelopes, such as de bohor reedbuck, sitatunga (de most aquatic antelope of the Sudd, mostly inhabiting permanent swampland), the endangered Nile lechwe (no for permanent swampland insyd, but generally near de water ein edge den often dey walk for shallow water insyd), den de white-eared kob (further away from de permanent swampland).[13] White-eared kob, tiang den Mongalla gazelle dey take part for one of de largest mammal migrations insyd for Earth top, wey e nomba about 1.2 million individuals for total insyd.[15][16] Dem frequent de shallow water Nile crocodiles den hippopotamuses. For more upland areas insyd dem know de Sudd as an historic habitat give de endangered painted hunting dog, wey howeva go already exterminate for de region insyd.[17]

Threats den preservation

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De long-running civil war in Southern Sudan seriously disrupt conservation efforts for de Sudd insyd, especially as de widespread availability of weapons encourage wildlife poaching, wey dey include of elephants. Der dey three game reserves: Zeraf Island between de Zeraf River den de Nile, Shambe Reserve, den Mongalla Game Reserve.

Jonglei diversion canal

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De early explorers wey dey search give de source of de Nile experience considerable difficulties, samtimes taking months to get thru de Sudd. For ein 1972 book insyd The White Nile, Alan Moorehead wey e say of de Sudd, "der dey no more formidable swamp for de world insyd".[18] Dem sustain de Sudd swamp by de water from de southwestern tributaries (de Bahr el Ghazal system) den dey consume a proportion of de main river thru evaporation den transpiration.

Sir William Garstin, Undersecretary of State of Public Works of Egypt, create de first detailed proposal give digging a canal east of de Sudd for 1907 insyd.[19] By bypassing de swamps, evaporation of de Nile ein water go vastly decrease, wey go allow an increase for de area of cultivatable land insyd for Egypt insyd by 8,100 km2 (2,000,000 acres). De Egyptian government for de 1930s insyd propose digging a canal east of de Sudd to divert water from de Bahr al Jabal above de Sudd to a point farther down de White Nile, wey e bypass de swamps den e carry de White Nile ein water directly to de main channel of de river.[20]

Dem study de Jonglei Canal scheme by de government of Egypt for 1946 insyd, den dem develop plans between 1954 den 1959. Construction work for de canal top begin for 1978 insyd, but de outbreak of political instability for Sudan insyd hold up work give many years. By 1984 wen de Sudan People's Liberation Army bring de works to a halt, dem excavate 240 km of de canal of a total of 360 km. De rusting remains of de giant German-built excavation machine—variously dem nickname am either "Sarah" anaa "Lucy"[21]—dey visible for a Google Earth image top at de south end of de canal, wey dem locate am since dem disable am by a missile.[22] Wen dem restore peace for 2000 insyd, speculation grow about a restart of de project. Howeva, for 21 February 2008 top, de Sudanese government say de revival of de project no dey be a priority. Nevertheless, for 2008 insyd, Sudan den Egypt gree to restart de project den finish de canal for 24 years insyd.[23] South Sudan gain independence for 2011 insyd.

Dem estimate am dat de Jonglei canal project go produce 3.5–4.8 billion m3 of water per year (equal to a mean annual discharge of 110–152 m3/s (3 883–5 368 ft3/s), an increase of around 5–7% of Egypt ein current water supply.[16] Dem go share canal ein benefits by Egypt den Sudan, plus de expected damage wey dey fall for South Sudan top.[23] De complex environmental den social issues wey dem involve, dey include de collapse of fisheries, drying of grazing lands,[24] a drop of groundwater levels, den a reduction of rainfall for de region insyd,[25] wey e limit de practicality of de project. De draining of de Sudd dey likely to have environmental effects comparable to de drying of Lake Chad anaa de draining of de Aral Sea.

Make you sanso see

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References

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  1. ↑ Gaudet, John J.; Falconer, A. (1983). Remote sensing for tropical freshwater bodies. The problem of floating islands on Lake Naivasha. Nairobi, Kenya: Regional Remote Sensing Facility.
  2. ↑ The New Oxford American Dictionary (NOAD), 3rd edition.
  3. ↑ Dumont, Henri J., ed. (2009). "A Description of the Nile Basin, and a Synopsis of Its History, Ecology, Biogeography, Hydrology, and Natural Resources". The Nile Origin, Environments, Limnology and Human Use. Monographiae Biologicae. Vol. 89. Springer Science + Business Media B.V. pp. 1–21. ISBN 978-1-4020-9725-6.
  4. ↑ Kirwan, L.P. (1957). "Rome beyond The Southern Egyptian Frontier". Geographical Journal. 123 (1): 13–19. Bibcode:1957GeogJ.123...13K. doi:10.2307/1790717. JSTOR 1790717.
  5. ↑ Lunt, Mark F.; Palmer, Paul I.; Feng, Liang; et al. (2019). "An increase in methane emissions from tropical Africa between 2010 and 2016 inferred from satellite data". Atmospheric Chemistry and Physics. 19 (23): 14721–14740. Bibcode:2019ACP....1914721L. doi:10.5194/acp-19-14721-2019. hdl:20.500.11820/013be268-2ebf-478a-a9d0-1e80f8c4b888. S2CID 198448426.
  6. ↑ "Climate change: Methane pulse detected from South Sudan wetlands". BBC News. 2019.
  7. ↑ Sutcliffe, J.V.; Parks, Y.P. (1999). IAHS Special Publication No. 5. Wallingford, UK.{{cite book}}: CS1 maint: location missing publisher (link)
  8. 1 2 Mefit-Babtie Srl (1983). Development Studies of the Jonglei Canal Area, Range Ecology Survey, Final Report, Volume 2, Background. Khartoum, Sudan: USAID PCE-I-00-96-00002-00.
  9. 1 2 Baecher, G. (2000). The Nile Basin – Environmental transboundary opportunities and constraint analysis. USAID PCE-I-00-96-00002-00.
  10. ↑ Zahran, A.B. 1986. Sudan Rainfall Variability – Towards a Drought Assessment Model. Interna. Confer. on water Resources Needs & Planning in Drought Prone Areas, 85–106
  11. ↑ Peterson, 2008
  12. ↑ Sutcliffe, J.V. (1974). "A Hydrological Study of the Southern Sudd Region of the Upper Nile". Hydrological Science Bulletin. 19 (2): 237–255. doi:10.1080/02626667409493903.
  13. 1 2 3 Green, J.; A.I. El-Moghraby (2009). "Swamps of the Upper White Nile". In H.J. Dumont (ed.). The Nile. Monographiae Biologicae. Vol. 89. Springer Science + Business Media B.V. pp. 193–204. ISBN 978-1-4020-9725-6.
  14. ↑ Neumann, D.; H. Obermaier; T. Moritz (2016). "Annotated checklist for fishes of the Main Nile Basin in the Sudan and Egypt based on recent specimen records (2006–2015)". Cybium. 40 (4): 287–317. doi:10.26028/cybium/2016-404-004.
  15. ↑ "Massive Animal Herds Flourishing Despite Sudan War, Survey Reveals". National Geographic. Archived from the original on 14 June 2007. January 2007
  16. 1 2 Furniss, C. (2010) "Draining Africa's Eden". Geographical. 2010. Geographical, April 2010.
  17. ↑ C. Michael Hogan. 2009. Painted Hunting Dog: Lycaon pictus, GlobalTwitcher.com, ed. N. Stromberg Archived 9 December 2010 at the Wayback Machine
  18. ↑ Moorehead, Alan (1972). The White Nile. London: Book Club Associates. p. 85.
  19. ↑ "The Egyptian Sudan, its history and monuments". archive.org. 1907.
  20. ↑ "Big Canal To Change Course of Nile River", October 1933, Popular Science, short article on top-right of page with map
  21. ↑ "Environment: Sarah Digs a Great Canal". Time. 10 January 1983. Archived from the original on 4 November 2012. Retrieved 24 May 2010.
  22. ↑ Google Earth image
  23. 1 2 Ahmad, A.M. (2008) Post-Jonglei planning in southern Sudan: combining environment with development Archived 2 February 2013 at archive.today Environment and Urbanization, October 2008
  24. ↑ Koang Tut Jing (8 September 2006). "Jonglei Canal Project Is A Looming Catastrophe". Gurtong. Archived from the original on 18 July 2011. Retrieved 22 October 2010.
  25. ↑ De Villiers, Marq, 2001. Water: The Fate of Our Most Precious Resource. Mariner Books. ISBN 978-0-618-12744-3

Bibliography

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