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Okavango Delta

April 19, 2023

The Okavango Delta[2] (or Okavango Grassland; formerly spelled "Okovango" or "Okovanggo") in Botswana is a vast inland delta formed where the Okavango River reaches a tectonic trough at an altitude of 930–1,000 m[3] in the central part of the endorheic basin of the Kalahari. It is an UNESCO World Heritage Site as one of the few interior delta systems that do not flow into a sea or ocean, with a wetland system that is largely intact.[4] All the water reaching the delta is ultimately evaporated and transpired. Each year, about 11 cubic kilometres (2.6 cu mi) of water spreads over the 6,000–15,000 km2 (2,300–5,800 sq mi) area. Some flood waters drain into Lake Ngami.[5] The area was once part of Lake Makgadikgadi, an ancient lake that had mostly dried up by the early Holocene.[6]

Okavango Delta
UNESCO World Heritage Site
Map of the delta with basin boundary as dashed line
LocationBotswana
CriteriaNatural: vii, ix, x
Reference1432
Inscription2014 (38th Session)
Area2,023,590 ha
Buffer zone2,286,630 ha
Coordinates19°17′00″S 22°54′00″E / 19.28333°S 22.90000°E / -19.28333; 22.90000
Official nameOkavango Delta System
Designated12 September 1996
Reference no.879[1]
Location of Okavango Delta in Botswana
Satellite image (SeaWiFS) of Okavango Delta, with national borders added
Typical region in the Okavango Delta, with free canals and lakes, swamps and islands

The Moremi Game Reserve is on the eastern side of the delta. The delta was named as one of the Seven Natural Wonders of Africa, which were officially declared on 11 February 2013 in Arusha, Tanzania.[7] On 22 June 2014, the Okavango Delta became the 1000th site to be officially inscribed on the UNESCO World Heritage List.[8][4]

Geography

Floods

The Okavango is produced by seasonal flooding. The Okavango River drains the summer (January–February) rainfall from the Angola highlands and the surge flows 1,200 km (750 mi) in around one month. The waters then spread over the 250 by 150 km (155 by 93 mi) area of the delta over the next four months (March–June). The high temperature of the delta causes rapid transpiration and evaporation, resulting in 3 cycles of rising and falling water level[9] that were not fully understood until the early 20th century. The flood peaks between June and August, during Botswana's dry winter months, when the delta swells to three times its permanent size, attracting animals from kilometres around and creating one of Africa’s greatest concentrations of wildlife.

The delta is very flat, with less than 2 m (6 ft 7 in) variation in height across its 15,000 km2 (5,800 sq mi),[10] while the water drops about 60 m from Mohembo to Maun.[3][11][12]

Water flow

Lagoons

 
Shinde Lagoon, seen from the air

When the water levels gradually recede, water remains in major canals and river beds, in waterholes and in a number of larger lagoons, which then attract increasing numbers of animals. Photo-safari camps and lodges are found near some of these lagoons. Among the larger lagoons are:

Salt islands

The agglomeration of salt around plant roots leads to barren white patches in the centre of many of the thousands of islands, which have become too salty to support plants, aside from the odd salt-resistant palm tree. Trees and grasses grow in the sand around the edges of the islands that have not become too salty yet.

About 70% of the islands began as termite mounds (often Macrotermes spp.), where a tree then takes root on the mound of soil.[13]

Chief's Island

Chief's Island, the largest island in the delta, was formed by a fault line which uplifted an area over 70 km long (43 mi) and 15 km wide (9.3 mi). Historically, it was reserved as an exclusive hunting area for the chief, but is now a protected area for wildlife. It now provides the core area for much of the resident wildlife when the waters rise.[14]

Climate

 
Aerial view of delta as floodwaters recede, August 2012

The Delta's profuse greenery is not the result of a wet climate; rather, it is an oasis in an arid country. The average annual rainfall is 450 mm (18 in) (approximately one-third that of its Angolan catchment area) and most of it falls between December and March in the form of heavy afternoon thunderstorms.

December to February are hot wet months with daytime temperatures as high as 40 °C (104 °F), warm nights, and humidity levels fluctuating between 50 and 80%. From March to May, the temperature reduces, with a maximum of 30 °C (86 °F) during the day and mild to cool nights. The rains quickly dry up leading into the dry, cool winter months of June to August. Daytime temperatures at this time of year are mild to warm, but the temperature falls considerably after sunset. Nights can be cold in the delta, with temperatures barely above freezing.[15]

The September to November span has the heat and atmospheric pressure build up once more, as the dry season slides into the rainy season. October is the most challenging month for visitors: daytime temperatures often push past 40 °C (104 °F) and the dryness is only occasionally broken by a sudden cloudburst.[16]

Fauna of the delta

 
A cheetah silhouetted against a sunset in the delta

The Okavango Delta is both a permanent and seasonal home to a wide variety of wildlife which is now a popular tourist attraction.[17] All of the big five game animals—the lion, leopard, African buffalo, African bush elephant and rhinoceros (both black and white rhinoceros)—are present.[18]

Other species include giraffe, blue wildebeest, plains zebra, hippopotamus,[19] impala, common eland, greater kudu, sable antelope, roan antelope, puku, lechwe, waterbuck, sitatunga, tsessebe, cheetah,[20] African wild dog, spotted hyena, black-backed jackal, caracal, serval, aardvark, aardwolf, bat-eared fox, African savanna hare, honey badger, crested porcupine, common warthog, chacma baboon, vervet monkey and Nile crocodile.[21]

The delta also hosts over 400 bird species, including the helmeted guineafowl, African fish eagle, Pel's fishing owl, Egyptian goose, South African shelduck, African jacana, African skimmer, marabou stork, crested crane, African spoonbill, African darter, southern ground hornbill, wattled crane,[22] lilac-breasted roller, secretary bird, and common ostrich.[23] Prime bird-watching areas are those with a mix of habitats such as the panhandle, the seasonal delta and the parts of the Moremi Game Reserve that are close to the water.[24]

Since 2005, the protected area has been considered a Lion Conservation Unit together with Hwange National Park.[25]

 
Small gathering of lechwe antelopes, Okavango Delta

The most abundant large mammal is the lechwe, with estimates suggesting approximately 88,000 individuals.[26] The lechwe a bit larger than an impala, with elongated hooves and a water-repellent substance on its legs that enable rapid movement through knee-deep water. Lechwe graze on aquatic plants and, like the waterbuck, take to water when threatened by predators. Only the males have horns.[27]

Fish

The Okavango Delta is home to 71 fish species, including the tigerfish, species of tilapia, and various species of catfish. Fish sizes range from the 1.4 m (4.6 ft) African sharptooth catfish to the 3.2 cm (1.3 in) sickle barb. The same species are found in the Zambezi River, indicating an historic link between the two river systems.[28]

Flora of the delta

The Okavango Delta is home to 1068 plants which belong to 134 families and 530 genera.[29] There are five important plant communities in the perennial swamp: Papyrus cyperus in the deeper waters, Miscanthus in the shallowly flooded sites, and Phragmites australis, Typha capensis and Pycreus in between. The swamp-dominant species, which are usually found in the perennial swamp, also extend far into the seasonally inundated area.[16] Papyrus cyperus reeds beds grow best in slow flowing waters of medium depth and are prominent at the channel sides. On the islands and mainlands edges above the flooded grasslands different communities of flora are found. These species are located according to their water preference: for instance Philenoptera violacea requires little water, is found at the highest elevations in the perennial swamps, and is common on drier seasonal swamp islands. Trees restricted to islands within the perennial swamp are a mixture of the palm Hyphaene petersiana and acacia.[29][30]

The mainland in the delta is characterized by mosaic of grassland and woodland communities composed of trees, shrubs and understory herbs, basically the vegetation is notably drier than the swamp. Acacia, Boscia, Combretum and Terminalia are some of the principal genera which make up the majority of plants within the Okavango Delta. The natural phenomenon of the annual flood in the dry season and the distinct rainy season in time of low rain is the result of the exceptionally high plant diversity within the delta.[29]

The plants of the delta play an important role in providing cohesion for the sand. The banks or levees of a river normally have a high mud content, and this combines with the sand in the river’s load to continuously build up the river banks. The river’s load In the delta consists almost entirely of sand, because the clean waters of the Okavango contain little mud. The plants capture the sand, acting as the glue and making up for the lack of mud, and in the process creating further islands on which more plants can take root.

This process is not important in the formation of linear islands. They are long and thin and often curved like a gently meandering river because they are actually the natural banks of old river channels which have become blocked up by plant growth and sand deposition, resulting in the river changing course and the old river levees becoming islands. Due to the flatness of the delta and the large tonnage of sand flowing into it from the Okavango River, the floor of the delta is slowly but constantly rising. Where channels are today, islands will be tomorrow and then new channels may wash away these existing islands.[31]

People

 
Hambukushu guide poles his makoro on delta floodwaters

The Okavango Delta peoples consist of five ethnic groups, each with its own ethnic identity and language. They are Hambukushu (also known as Mbukushu, Bukushu, Bukusu, Mabukuschu, Ghuva, Haghuva), Dceriku (Dxeriku, Diriku, Gciriku, Gceriku, Giriku, Niriku), Wayeyi (Bayei, Bayeyi, Yei), Bugakhwe (Kxoe, Khwe, Kwengo, Barakwena, G/anda) and ||anikhwe (Gxanekwe, //tanekwe, River Bushmen, Swamp Bushmen, G//ani, //ani, Xanekwe). The Hambukushu, Dceriku, and Wayeyi have traditionally engaged in mixed economies of millet/sorghum agriculture, fishing, hunting, the collection of wild plant foods, and pastoralism.

The Bugakhwe and ||anikwhe are Bushmen, who have traditionally practised fishing, hunting, and the collection of wild plant foods; Bugakhwe used both forest and riverine resources, while the ||anikhwe mostly focused on riverine resources. The Hambukushu, Dceriku, and Bugakhwe are present along the Okavango River in Angola and in the Caprivi Strip of Namibia, and small numbers of Hambukushu and Bugakhwe are in Zambia, as well. Within the Okavango Delta, over the past 150 years or so, Hambukushu, Dceriku, and Bugakhwe have inhabited the panhandle and the Magwegqana in the northeastern delta. ||anikhwe have inhabited the panhandle and the area along the Boro River through the delta, as well as the area along the Boteti River.

The Wayeyi[32] have inhabited the area around Seronga as well as the southern delta around Maun, and a few Wayeyi[33] live in their putative ancestral home in the Caprivi Strip. Within the past 20 years many people from all over the Okavango have migrated to Maun, the late 1960s and early 1970s over 4,000 Hambukushu refugees from Angola were settled in the area around Etsha in the western Panhandle.

The Okavango Delta has been under the political control of the Batawana (a Tswana nation) since the late 18th century.[34] Led by the house of Mathiba I, the leader of a Bangwato offshoot, the Batawana established complete control over the delta in the 1850s as the regional ivory trade exploded.[35] Most Batawana, however, have traditionally lived on the edges of the delta, due to the threat that the tsetse fly poses to their cattle. During a hiatus of some 40 years, the tsetse fly retreated and most Batawana lived in the swamps from 1896 through the late 1930s. Since then, the edge of the delta has become increasingly crowded with its growing human and livestock populations.

 
Flood-control bunds for flood recession cropping in the molapo of the Okavango, Botswana

Molapos (water streams)

After the flooding season, the waters in the lower parts of the delta, near the base, recede, leaving moisture behind in the soil. This residual moisture is used for planting fodder and other crops that can thrive on it. This land is locally known as molapo.

During 1974 to 1978, the floods were more intensive than normal and flood recession cropping was not possible, so severe food and fodder shortages occurred. In response, the Molapo Development Project was initiated. It protected the molapo areas with bunds to control the flooding and prevent severe flooding. The bunds are provided with sluice gates so the stored water can be released and flood recession cropping can start.[36]

Possible threats

One possible threat is oil exploration by Canadian company ReconAfrica. Initial exploration in April 2021 revealed oil deposits in sedimentary rock.[37] Environmentalists are concerned that the project will have a negative ecological impact and that some of the main bodies of water could be threatened.[38][39][40] ReconAfrica has stated, "There will be no damage to the ecosystem from the planned activities."[41][42]

The Namibian government has presented plans to build a hydropower station in the Zambezi Region, which would regulate the Okavango's flow to some extent. While proponents argue that the effect would be minimal, environmentalists argue that this project could destroy most of the rich animal and plant life in the delta.[43] Other threats include local human encroachment and regional extraction of water in both Angola and Namibia.[44][45]

South African filmmaker and conservationist Rick Lomba warned in the 1980s of the threat of cattle invasion to the area. His documentary The End of Eden portrayed his lobbying on behalf of the delta.

The Okavango catchment is projected to experience decreasing annual rainfall as well as increasing temperatures as a result of global warming.[46] The effects of global warming are likely to result in reductions in the extent of floodplains in the Okavango Delta, which will have significant impacts on water availability as well as livestock rearing and agricultural activities in the region.[47]

See also

References

  1. ^ "Okavango Delta System". Ramsar Sites Information Service. Retrieved 25 April 2018.
  2. ^ Ross, Karen (1987). Okavango, jewel of the Kalahari. London: BBC Books. ISBN 0-563-20545-8. OCLC 17978845.
  3. ^ a b "Ramsar Information Sheet" (PDF). 20 November 1996. The total drop in altitude between Mohembo and Maun, a distance of440 km, is only 62 metres, giving a gradient of approximately 1:7,000 only{{cite web}}: CS1 maint: url-status (link)
  4. ^ a b Centre, UNESCO World Heritage. "Twenty six new properties added to World Heritage List at Doha meeting". whc.unesco.org. Retrieved 4 April 2018.
  5. ^ Keen, Cecil (1997). "Okavango Delta".
  6. ^ McCarthy, T. S. (1993). "The great inland deltas of Africa". Journal of African Earth Sciences. 17 (3): 275–291. Bibcode:1993JAfES..17..275M. doi:10.1016/0899-5362(93)90073-Y.
  7. ^ . sevennaturalwonders.org. Archived from the original on 21 December 2015. Retrieved 22 March 2013.
  8. ^ Centre, UNESCO World Heritage. "World Heritage List reaches 1000 sites with inscription of Okavango Delta in Botswana". whc.unesco.org. Retrieved 4 April 2018.
  9. ^ C. N. Kurugundla; N. M. Moleele; K.Dikgola. "Flow Partitioning Within the Okavango Delta –A Pre-requisite for Environmental Flow Assessment for Human Livelihoods and Sustainable Biodiversity Management" (PDF). University of Botswana. pp. 8–9.
  10. ^ . Archived from the original on 19 July 2009.
  11. ^ Wehberg, Jan (31 December 2013). "Okavango Basin - Physicogeographical setting". Biodiversity and Ecology. 5: 11. doi:10.7809/b-e.00236.
  12. ^ Gumbricht, T. (1 September 2001). "The topography of the Okavango Delta, Botswana, and its tectonic and sedimentological implications". South African Journal of Geology. 104 (3): 243–264. doi:10.2113/1040243.
  13. ^ Dunford, Chris. "Nature explored:Moremi/Okavango Delta in August".
  14. ^ "Okavango delta Botswana | Mokoro and boating safaris". Okavango Safaris. Retrieved 29 May 2020.
  15. ^ "Botswana climate: average weather, temperature, precipitation, best time". www.climatestotravel.com. Retrieved 15 May 2020.
  16. ^ a b UNEP-WCMC (22 May 2017). "OKAVANGO DELTA". World Heritage Datasheet. Retrieved 17 May 2021.
  17. ^ Bradley, John H. (October 2009). . Cape Town to Cairo Website. CapeTowntoCairo.com. Archived from the original on 19 November 2009. Retrieved 10 November 2009.
  18. ^ Galpine, N. J. (2006). "Boma management of black and white rhinoceros at Mombo, Okavango Delta—Some lessons" (PDF). Ecological Journal. 7: 55−61.
  19. ^ McCarthy, T. S.; Ellery, W. N.; Bloem, A. (1998). "Some observations on the geomorphological impact of hippopotamus (Hippopotamus amphibius L.) in the Okavango Delta, Botswana". African Journal of Ecology. 36 (1): 44−56. doi:10.1046/j.1365-2028.1998.89-89089.x.
  20. ^ Klein, R. (2007). "Status report for the cheetah in Botswana" (PDF). Cat News. Special Issue 1: 13−21.
  21. ^ Wallace, K. M.; Leslie, A. J. (2008). "Diet of the Nile crocodile (Crocodylus niloticus) in the Okavango Delta, Botswana". Journal of Herpetology. 42 (2): 361−368. doi:10.1670/07-1071.1. S2CID 46987629.
  22. ^ Alonso, L. E.; Nordin, L.-A., eds. (2003). A rapid biological assessment of the aquatic ecosystems of the Okavango Delta, Botswana: High Water Survey. RAP Bulletin of Biological Assessment. Vol. 27. Washington, DC: Conservation International. ISBN 1-881173-70-4.
  23. ^ Mbaiwa, J. E.; Mbaiwa, O. I. (2006). "The effects of veterinary fences on wildlife populations in Okavango Delta, Botswana". International Journal of Wilderness. 12 (3): 17−41. hdl:10311/28.
  24. ^ Adrian, Bailey (1998). OKAVANGO; Africa's Wetland Wilderness. Cape Town, South Africa: Struik Publishers (Pty) Ltd. pp. 66–73. ISBN 1868720411.
  25. ^ IUCN Cat Specialist Group (2006). Conservation Strategy for the Lion Panthera leo in Eastern and Southern Africa. Pretoria, South Africa: IUCN.
  26. ^ Chase, M.; Schlossberg, S.; Landen, K.; Sutcliffe, R.; Seonyatseng, E.; Keitsile, A. & Flyman, M. (2018). Dry Season Aerial Survey of Elephants and Wildlife in Northern Botswana (Report). Botswana: Elephants Without Borders, the Department of Wildlife and National Parks and the Great Elephant Census.
  27. ^ "Lechwe | mammal". Encyclopedia Britannica. Retrieved 17 May 2021.
  28. ^ (PDF). Archived from the original (PDF) on 6 July 2011. Retrieved 2 February 2011.{{cite web}}: CS1 maint: archived copy as title (link)
  29. ^ a b c Ramberg, Lars (2006). "Species diversity of the Okavango Delta,Botswana". Aquatic Sciences. 3: 316 – via Researchgate.
  30. ^ Toerien, D. K. (15 August 1976). "Geologie van die Tsitsikamakusstrook". Koedoe. 19 (1). doi:10.4102/koedoe.v19i1.1179. ISSN 2071-0771.
  31. ^ . blog.africabespoke.com. Archived from the original on 19 July 2009. Retrieved 4 April 2018.
  32. ^ "Wayeyi". Minority Rights Group. 19 June 2015. Retrieved 2 June 2021.
  33. ^ Campbell, Alexander Colin; N’teta, Doreen (March 1980). "The National Museum and Art Gallery, Gaborone, Botswana". Museum International. 32 (1–2): 61–66. doi:10.1111/j.1468-0033.1980.tb01909.x. ISSN 1350-0775.
  34. ^ Segolodi, Moanaphuti (1940). "Ditso Tsa Batawana". {{cite journal}}: Cite journal requires |journal= (help)
  35. ^ Morton, Barry (1997). "The Hunting Trade and the Reconstruction of Northern Tswana Societies after the Difaqane, 1838–1880". South African Historical Journal. 36: 220–239. doi:10.1080/02582479708671276.
  36. ^   Kortenhorst, L. F.; et al. (1986). Development of flood-recession cropping in the molapo's of the Okavango Delta, Botswana (PDF). Annual Report 1986. Wageningen, The Netherlands: International Institute for Land Reclamation and Improvement. pp. 8–19.
  37. ^ Ltd, Reconnaissance Energy Africa. "ReconAfrica's First of Three Wells Confirms a Working Petroleum System in the Kavango Basin, Namibia". www.newswire.ca. Retrieved 27 April 2021.
  38. ^ "A Big Oil Project in Africa Threatens Fragile Okavango Region". Yale E360. Retrieved 27 April 2021.
  39. ^ "Growing concern over Okavango oil exploration as community alleges shutout". Mongabay Environmental News. 22 March 2021. Retrieved 2 June 2021.
  40. ^ "Test drilling for oil in Namibia's Okavango region poses toxic risk". Animals. 12 March 2021. Retrieved 27 April 2021.
  41. ^ "Frequently Asked Questions: ReconAfrica Initial Drilling Project". reconafrica.com. Retrieved 30 April 2021.
  42. ^ Wilson-Spath, Andreas (15 December 2020). "OP-ED: Paradise is closing down: The ghastly spectre of oil drilling and fracking in fragile Okavango Delta". Daily Maverick. Retrieved 2 June 2021.
  43. ^ "FindArticles.com - CBSi". findarticles.com. Retrieved 4 April 2018.
  44. ^ . www.okavangodelta.com. Archived from the original on 22 February 2020. Retrieved 4 April 2018.
  45. ^ "Chinese-Angolan project in Angola harvests over 1,200 tons of rice". 11 March 2016.
  46. ^ ASSAR (2019). What global warming of 1.5°C and higher means for Botswana (PDF). Adaptation at Scale in Semi Arid Regions (ASSAR).
  47. ^ Murray-Hudson, M.; Wolski, P.; Ringrose, S. (2006). "Scenarios of the impact of local and upstream changes in climate and water use on hydro-ecology in the Okavango Delta, Botswana". Journal of Hydrology. Water Resources in Regional Development: The Okavango River. 331 (1): 73–84. Bibcode:2006JHyd..331...73M. doi:10.1016/j.jhydrol.2006.04.041.

Further reading

  • Allison, P. (2007). Whatever You Do, Don't Run: True Tales Of A Botswana Safari Guide. Globe Pequot. ISBN 9780762745654.
  • Bock, J. (2002). "Learning, Life History, and Productivity: Children's lives in the Okavango Delta of Botswana". Human Nature. 13 (2): 161–198. doi:10.1007/s12110-002-1007-4. PMID 26192757. S2CID 28985956.

External links

 
Wikimedia Commons has media related to Okavango Delta.
 
Wikivoyage has a travel guide for Okavango Delta.
  • Conservation International
  • Okavango Delta concession areas
  • Flow : information for Okavango Delta planning is the weblog of the Library of the Harry Oppenheimer Okavango Research Institute
  • Flood-recession cropping in the molapos of the Okavango Delta
  • Current Okavango water levels, weather data and satellite images
  • 1986 Documentary The End of Eden by Rick Lomba
  • Southern African Game Reserves - Okavango Delta

April 19, 2023
okavango, delta, okavango, grassland, formerly, spelled, okovango, okovanggo, botswana, vast, inland, delta, formed, where, okavango, river, reaches, tectonic, trough, altitude, central, part, endorheic, basin, kalahari, unesco, world, heritage, site, interior. The Okavango Delta 2 or Okavango Grassland formerly spelled Okovango or Okovanggo in Botswana is a vast inland delta formed where the Okavango River reaches a tectonic trough at an altitude of 930 1 000 m 3 in the central part of the endorheic basin of the Kalahari It is an UNESCO World Heritage Site as one of the few interior delta systems that do not flow into a sea or ocean with a wetland system that is largely intact 4 All the water reaching the delta is ultimately evaporated and transpired Each year about 11 cubic kilometres 2 6 cu mi of water spreads over the 6 000 15 000 km2 2 300 5 800 sq mi area Some flood waters drain into Lake Ngami 5 The area was once part of Lake Makgadikgadi an ancient lake that had mostly dried up by the early Holocene 6 Okavango DeltaUNESCO World Heritage SiteMap of the delta with basin boundary as dashed lineLocationBotswanaCriteriaNatural vii ix xReference1432Inscription2014 38th Session Area2 023 590 haBuffer zone2 286 630 haCoordinates19 17 00 S 22 54 00 E 19 28333 S 22 90000 E 19 28333 22 90000Ramsar WetlandOfficial nameOkavango Delta SystemDesignated12 September 1996Reference no 879 1 Location of Okavango Delta in BotswanaSatellite image SeaWiFS of Okavango Delta with national borders added Typical region in the Okavango Delta with free canals and lakes swamps and islands The Moremi Game Reserve is on the eastern side of the delta The delta was named as one of the Seven Natural Wonders of Africa which were officially declared on 11 February 2013 in Arusha Tanzania 7 On 22 June 2014 the Okavango Delta became the 1000th site to be officially inscribed on the UNESCO World Heritage List 8 4 Contents 1 Geography 1 1 Floods 1 2 Water flow 1 3 Lagoons 1 4 Salt islands 1 5 Chief s Island 2 Climate 3 Fauna of the delta 3 1 Fish 4 Flora of the delta 5 People 6 Molapos water streams 7 Possible threats 8 See also 9 References 10 Further reading 11 External linksGeography EditFloods Edit The Okavango is produced by seasonal flooding The Okavango River drains the summer January February rainfall from the Angola highlands and the surge flows 1 200 km 750 mi in around one month The waters then spread over the 250 by 150 km 155 by 93 mi area of the delta over the next four months March June The high temperature of the delta causes rapid transpiration and evaporation resulting in 3 cycles of rising and falling water level 9 that were not fully understood until the early 20th century The flood peaks between June and August during Botswana s dry winter months when the delta swells to three times its permanent size attracting animals from kilometres around and creating one of Africa s greatest concentrations of wildlife The delta is very flat with less than 2 m 6 ft 7 in variation in height across its 15 000 km2 5 800 sq mi 10 while the water drops about 60 m from Mohembo to Maun 3 11 12 Water flow Edit Lagoons Edit Shinde Lagoon seen from the air When the water levels gradually recede water remains in major canals and river beds in waterholes and in a number of larger lagoons which then attract increasing numbers of animals Photo safari camps and lodges are found near some of these lagoons Among the larger lagoons are Dombo Hippo Pool 19 12 1 8 S 23 38 25 8 E 19 200500 S 23 640500 E 19 200500 23 640500 Gcodikwe Lagoon 19 9 54 S 23 14 24 E 19 16500 S 23 24000 E 19 16500 23 24000 Guma Lagoon 18 57 52 2 S 22 22 40 8 E 18 964500 S 22 378000 E 18 964500 22 378000 Jerejere Lagoon Hippo Pool 19 5 16 8 S 23 1 12 E 19 088000 S 23 02000 E 19 088000 23 02000 Moanachira Lagoon Sausage Island 19 3 23 4 S 23 3 44 3 E 19 056500 S 23 062306 E 19 056500 23 062306 Moanachira Lagoon 19 3 45 S 23 5 24 E 19 06250 S 23 09000 E 19 06250 23 09000 Shinde Lagoon 19 6 18 S 23 9 14 4 E 19 10500 S 23 154000 E 19 10500 23 154000 Xakanaxa Lagoon 19 10 48 S 23 23 42 E 19 18000 S 23 39500 E 19 18000 23 39500 Xhamu Lagoon 19 10 1 2 S 23 16 15 6 E 19 167000 S 23 271000 E 19 167000 23 271000 Xhobega Lagoon 19 11 0 6 S 23 12 25 2 E 19 183500 S 23 207000 E 19 183500 23 207000 Xugana Lagoon 19 4 10 2 S 23 6 0 E 19 069500 S 23 10000 E 19 069500 23 10000 Zibadiania Lagoon 18 34 12 S 23 32 6 E 18 57000 S 23 53500 E 18 57000 23 53500 Salt islands Edit The agglomeration of salt around plant roots leads to barren white patches in the centre of many of the thousands of islands which have become too salty to support plants aside from the odd salt resistant palm tree Trees and grasses grow in the sand around the edges of the islands that have not become too salty yet About 70 of the islands began as termite mounds often Macrotermes spp where a tree then takes root on the mound of soil 13 Chief s Island Edit Chief s Island the largest island in the delta was formed by a fault line which uplifted an area over 70 km long 43 mi and 15 km wide 9 3 mi Historically it was reserved as an exclusive hunting area for the chief but is now a protected area for wildlife It now provides the core area for much of the resident wildlife when the waters rise 14 Climate Edit Aerial view of delta as floodwaters recede August 2012 The Delta s profuse greenery is not the result of a wet climate rather it is an oasis in an arid country The average annual rainfall is 450 mm 18 in approximately one third that of its Angolan catchment area and most of it falls between December and March in the form of heavy afternoon thunderstorms December to February are hot wet months with daytime temperatures as high as 40 C 104 F warm nights and humidity levels fluctuating between 50 and 80 From March to May the temperature reduces with a maximum of 30 C 86 F during the day and mild to cool nights The rains quickly dry up leading into the dry cool winter months of June to August Daytime temperatures at this time of year are mild to warm but the temperature falls considerably after sunset Nights can be cold in the delta with temperatures barely above freezing 15 The September to November span has the heat and atmospheric pressure build up once more as the dry season slides into the rainy season October is the most challenging month for visitors daytime temperatures often push past 40 C 104 F and the dryness is only occasionally broken by a sudden cloudburst 16 Fauna of the delta Edit A cheetah silhouetted against a sunset in the delta The Okavango Delta is both a permanent and seasonal home to a wide variety of wildlife which is now a popular tourist attraction 17 All of the big five game animals the lion leopard African buffalo African bush elephant and rhinoceros both black and white rhinoceros are present 18 Other species include giraffe blue wildebeest plains zebra hippopotamus 19 impala common eland greater kudu sable antelope roan antelope puku lechwe waterbuck sitatunga tsessebe cheetah 20 African wild dog spotted hyena black backed jackal caracal serval aardvark aardwolf bat eared fox African savanna hare honey badger crested porcupine common warthog chacma baboon vervet monkey and Nile crocodile 21 The delta also hosts over 400 bird species including the helmeted guineafowl African fish eagle Pel s fishing owl Egyptian goose South African shelduck African jacana African skimmer marabou stork crested crane African spoonbill African darter southern ground hornbill wattled crane 22 lilac breasted roller secretary bird and common ostrich 23 Prime bird watching areas are those with a mix of habitats such as the panhandle the seasonal delta and the parts of the Moremi Game Reserve that are close to the water 24 Since 2005 the protected area has been considered a Lion Conservation Unit together with Hwange National Park 25 Small gathering of lechwe antelopes Okavango Delta The most abundant large mammal is the lechwe with estimates suggesting approximately 88 000 individuals 26 The lechwe a bit larger than an impala with elongated hooves and a water repellent substance on its legs that enable rapid movement through knee deep water Lechwe graze on aquatic plants and like the waterbuck take to water when threatened by predators Only the males have horns 27 Fish Edit The Okavango Delta is home to 71 fish species including the tigerfish species of tilapia and various species of catfish Fish sizes range from the 1 4 m 4 6 ft African sharptooth catfish to the 3 2 cm 1 3 in sickle barb The same species are found in the Zambezi River indicating an historic link between the two river systems 28 Flora of the delta EditThe Okavango Delta is home to 1068 plants which belong to 134 families and 530 genera 29 There are five important plant communities in the perennial swamp Papyrus cyperus in the deeper waters Miscanthus in the shallowly flooded sites and Phragmites australis Typha capensis and Pycreus in between The swamp dominant species which are usually found in the perennial swamp also extend far into the seasonally inundated area 16 Papyrus cyperus reeds beds grow best in slow flowing waters of medium depth and are prominent at the channel sides On the islands and mainlands edges above the flooded grasslands different communities of flora are found These species are located according to their water preference for instance Philenoptera violacea requires little water is found at the highest elevations in the perennial swamps and is common on drier seasonal swamp islands Trees restricted to islands within the perennial swamp are a mixture of the palm Hyphaene petersiana and acacia 29 30 The mainland in the delta is characterized by mosaic of grassland and woodland communities composed of trees shrubs and understory herbs basically the vegetation is notably drier than the swamp Acacia Boscia Combretum and Terminalia are some of the principal genera which make up the majority of plants within the Okavango Delta The natural phenomenon of the annual flood in the dry season and the distinct rainy season in time of low rain is the result of the exceptionally high plant diversity within the delta 29 The plants of the delta play an important role in providing cohesion for the sand The banks or levees of a river normally have a high mud content and this combines with the sand in the river s load to continuously build up the river banks The river s load In the delta consists almost entirely of sand because the clean waters of the Okavango contain little mud The plants capture the sand acting as the glue and making up for the lack of mud and in the process creating further islands on which more plants can take root This process is not important in the formation of linear islands They are long and thin and often curved like a gently meandering river because they are actually the natural banks of old river channels which have become blocked up by plant growth and sand deposition resulting in the river changing course and the old river levees becoming islands Due to the flatness of the delta and the large tonnage of sand flowing into it from the Okavango River the floor of the delta is slowly but constantly rising Where channels are today islands will be tomorrow and then new channels may wash away these existing islands 31 People Edit Hambukushu guide poles his makoro on delta floodwaters The Okavango Delta peoples consist of five ethnic groups each with its own ethnic identity and language They are Hambukushu also known as Mbukushu Bukushu Bukusu Mabukuschu Ghuva Haghuva Dceriku Dxeriku Diriku Gciriku Gceriku Giriku Niriku Wayeyi Bayei Bayeyi Yei Bugakhwe Kxoe Khwe Kwengo Barakwena G anda and anikhwe Gxanekwe tanekwe River Bushmen Swamp Bushmen G ani ani Xanekwe The Hambukushu Dceriku and Wayeyi have traditionally engaged in mixed economies of millet sorghum agriculture fishing hunting the collection of wild plant foods and pastoralism The Bugakhwe and anikwhe are Bushmen who have traditionally practised fishing hunting and the collection of wild plant foods Bugakhwe used both forest and riverine resources while the anikhwe mostly focused on riverine resources The Hambukushu Dceriku and Bugakhwe are present along the Okavango River in Angola and in the Caprivi Strip of Namibia and small numbers of Hambukushu and Bugakhwe are in Zambia as well Within the Okavango Delta over the past 150 years or so Hambukushu Dceriku and Bugakhwe have inhabited the panhandle and the Magwegqana in the northeastern delta anikhwe have inhabited the panhandle and the area along the Boro River through the delta as well as the area along the Boteti River The Wayeyi 32 have inhabited the area around Seronga as well as the southern delta around Maun and a few Wayeyi 33 live in their putative ancestral home in the Caprivi Strip Within the past 20 years many people from all over the Okavango have migrated to Maun the late 1960s and early 1970s over 4 000 Hambukushu refugees from Angola were settled in the area around Etsha in the western Panhandle The Okavango Delta has been under the political control of the Batawana a Tswana nation since the late 18th century 34 Led by the house of Mathiba I the leader of a Bangwato offshoot the Batawana established complete control over the delta in the 1850s as the regional ivory trade exploded 35 Most Batawana however have traditionally lived on the edges of the delta due to the threat that the tsetse fly poses to their cattle During a hiatus of some 40 years the tsetse fly retreated and most Batawana lived in the swamps from 1896 through the late 1930s Since then the edge of the delta has become increasingly crowded with its growing human and livestock populations Flood control bunds for flood recession cropping in the molapo of the Okavango BotswanaMolapos water streams EditAfter the flooding season the waters in the lower parts of the delta near the base recede leaving moisture behind in the soil This residual moisture is used for planting fodder and other crops that can thrive on it This land is locally known as molapo During 1974 to 1978 the floods were more intensive than normal and flood recession cropping was not possible so severe food and fodder shortages occurred In response the Molapo Development Project was initiated It protected the molapo areas with bunds to control the flooding and prevent severe flooding The bunds are provided with sluice gates so the stored water can be released and flood recession cropping can start 36 Possible threats EditOne possible threat is oil exploration by Canadian company ReconAfrica Initial exploration in April 2021 revealed oil deposits in sedimentary rock 37 Environmentalists are concerned that the project will have a negative ecological impact and that some of the main bodies of water could be threatened 38 39 40 ReconAfrica has stated There will be no damage to the ecosystem from the planned activities 41 42 The Namibian government has presented plans to build a hydropower station in the Zambezi Region which would regulate the Okavango s flow to some extent While proponents argue that the effect would be minimal environmentalists argue that this project could destroy most of the rich animal and plant life in the delta 43 Other threats include local human encroachment and regional extraction of water in both Angola and Namibia 44 45 South African filmmaker and conservationist Rick Lomba warned in the 1980s of the threat of cattle invasion to the area His documentary The End of Eden portrayed his lobbying on behalf of the delta The Okavango catchment is projected to experience decreasing annual rainfall as well as increasing temperatures as a result of global warming 46 The effects of global warming are likely to result in reductions in the extent of floodplains in the Okavango Delta which will have significant impacts on water availability as well as livestock rearing and agricultural activities in the region 47 See also Edit Wetlands portalKalahari BasinReferences Edit Okavango Delta System Ramsar Sites Information Service Retrieved 25 April 2018 Ross Karen 1987 Okavango jewel of the Kalahari London BBC Books ISBN 0 563 20545 8 OCLC 17978845 a b Ramsar Information Sheet PDF 20 November 1996 The total drop in altitude between Mohembo and Maun a distance of440 km is only 62 metres giving a gradient of approximately 1 7 000 only a href Template Cite web html title Template Cite web cite web a CS1 maint url status link a b Centre UNESCO World Heritage Twenty six new properties added to World Heritage List at Doha meeting whc unesco org Retrieved 4 April 2018 Keen Cecil 1997 Okavango Delta McCarthy T S 1993 The great inland deltas of Africa Journal of African Earth Sciences 17 3 275 291 Bibcode 1993JAfES 17 275M doi 10 1016 0899 5362 93 90073 Y Seven Natural Wonders of Africa Seven Natural Wonders sevennaturalwonders org Archived from the original on 21 December 2015 Retrieved 22 March 2013 Centre UNESCO World Heritage World Heritage List reaches 1000 sites with inscription of Okavango Delta in Botswana whc unesco org Retrieved 4 April 2018 C N Kurugundla N M Moleele K Dikgola Flow Partitioning Within the Okavango Delta A Pre requisite for Environmental Flow Assessment for Human Livelihoods and Sustainable Biodiversity Management PDF University of Botswana pp 8 9 Okavango Delta Archived from the original on 19 July 2009 Wehberg Jan 31 December 2013 Okavango Basin Physicogeographical setting Biodiversity and Ecology 5 11 doi 10 7809 b e 00236 Gumbricht T 1 September 2001 The topography of the Okavango Delta Botswana and its tectonic and sedimentological implications South African Journal of Geology 104 3 243 264 doi 10 2113 1040243 Dunford Chris Nature explored Moremi Okavango Delta in August Okavango delta Botswana Mokoro and boating safaris Okavango Safaris Retrieved 29 May 2020 Botswana climate average weather temperature precipitation best time www climatestotravel com Retrieved 15 May 2020 a b UNEP WCMC 22 May 2017 OKAVANGO DELTA World Heritage Datasheet Retrieved 17 May 2021 Bradley John H October 2009 Gliding in a Mokoro Through the Okavango Delta Botswana Cape Town to Cairo Website CapeTowntoCairo com Archived from the original on 19 November 2009 Retrieved 10 November 2009 Galpine N J 2006 Boma management of black and white rhinoceros at Mombo Okavango Delta Some lessons PDF Ecological Journal 7 55 61 McCarthy T S Ellery W N Bloem A 1998 Some observations on the geomorphological impact of hippopotamus Hippopotamus amphibius L in the Okavango Delta Botswana African Journal of Ecology 36 1 44 56 doi 10 1046 j 1365 2028 1998 89 89089 x Klein R 2007 Status report for the cheetah in Botswana PDF Cat News Special Issue 1 13 21 Wallace K M Leslie A J 2008 Diet of the Nile crocodile Crocodylus niloticus in the Okavango Delta Botswana Journal of Herpetology 42 2 361 368 doi 10 1670 07 1071 1 S2CID 46987629 Alonso L E Nordin L A eds 2003 A rapid biological assessment of the aquatic ecosystems of the Okavango Delta Botswana High Water Survey RAP Bulletin of Biological Assessment Vol 27 Washington DC Conservation International ISBN 1 881173 70 4 Mbaiwa J E Mbaiwa O I 2006 The effects of veterinary fences on wildlife populations in Okavango Delta Botswana International Journal of Wilderness 12 3 17 41 hdl 10311 28 Adrian Bailey 1998 OKAVANGO Africa s Wetland Wilderness Cape Town South Africa Struik Publishers Pty Ltd pp 66 73 ISBN 1868720411 IUCN Cat Specialist Group 2006 Conservation Strategy for the LionPanthera leoin Eastern and Southern Africa Pretoria South Africa IUCN Chase M Schlossberg S Landen K Sutcliffe R Seonyatseng E Keitsile A amp Flyman M 2018 Dry Season Aerial Survey of Elephants and Wildlife in Northern Botswana Report Botswana Elephants Without Borders the Department of Wildlife and National Parks and the Great Elephant Census Lechwe mammal Encyclopedia Britannica Retrieved 17 May 2021 Archived copy PDF Archived from the original PDF on 6 July 2011 Retrieved 2 February 2011 a href Template Cite web html title Template Cite web cite web a CS1 maint archived copy as title link a b c Ramberg Lars 2006 Species diversity of the Okavango Delta Botswana Aquatic Sciences 3 316 via Researchgate Toerien D K 15 August 1976 Geologie van die Tsitsikamakusstrook Koedoe 19 1 doi 10 4102 koedoe v19i1 1179 ISSN 2071 0771 Okavango Delta Part 2 blog africabespoke com Archived from the original on 19 July 2009 Retrieved 4 April 2018 Wayeyi Minority Rights Group 19 June 2015 Retrieved 2 June 2021 Campbell Alexander Colin N teta Doreen March 1980 The National Museum and Art Gallery Gaborone Botswana Museum International 32 1 2 61 66 doi 10 1111 j 1468 0033 1980 tb01909 x ISSN 1350 0775 Segolodi Moanaphuti 1940 Ditso Tsa Batawana a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help Morton Barry 1997 The Hunting Trade and the Reconstruction of Northern Tswana Societies after the Difaqane 1838 1880 South African Historical Journal 36 220 239 doi 10 1080 02582479708671276 Kortenhorst L F et al 1986 Development of flood recession cropping in the molapo s of the Okavango Delta Botswana PDF Annual Report 1986 Wageningen The Netherlands International Institute for Land Reclamation and Improvement pp 8 19 Ltd Reconnaissance Energy Africa ReconAfrica s First of Three Wells Confirms a Working Petroleum System in the Kavango Basin Namibia www newswire ca Retrieved 27 April 2021 A Big Oil Project in Africa Threatens Fragile Okavango Region Yale E360 Retrieved 27 April 2021 Growing concern over Okavango oil exploration as community alleges shutout Mongabay Environmental News 22 March 2021 Retrieved 2 June 2021 Test drilling for oil in Namibia s Okavango region poses toxic risk Animals 12 March 2021 Retrieved 27 April 2021 Frequently Asked Questions ReconAfrica Initial Drilling Project reconafrica com Retrieved 30 April 2021 Wilson Spath Andreas 15 December 2020 OP ED Paradise is closing down The ghastly spectre of oil drilling and fracking in fragile Okavango Delta Daily Maverick Retrieved 2 June 2021 FindArticles com CBSi findarticles com Retrieved 4 April 2018 Threats Okavango Delta www okavangodelta com Archived from the original on 22 February 2020 Retrieved 4 April 2018 Chinese Angolan project in Angola harvests over 1 200 tons of rice 11 March 2016 ASSAR 2019 What global warming of 1 5 C and higher means for Botswana PDF Adaptation at Scale in Semi Arid Regions ASSAR Murray Hudson M Wolski P Ringrose S 2006 Scenarios of the impact of local and upstream changes in climate and water use on hydro ecology in the Okavango Delta Botswana Journal of Hydrology Water Resources in Regional Development The Okavango River 331 1 73 84 Bibcode 2006JHyd 331 73M doi 10 1016 j jhydrol 2006 04 041 Further reading EditAllison P 2007 Whatever You Do Don t Run True Tales Of A Botswana Safari Guide Globe Pequot ISBN 9780762745654 Bock J 2002 Learning Life History and Productivity Children s lives in the Okavango Delta of Botswana Human Nature 13 2 161 198 doi 10 1007 s12110 002 1007 4 PMID 26192757 S2CID 28985956 External links Edit Wikimedia Commons has media related to Okavango Delta Wikivoyage has a travel guide for Okavango Delta Conservation International Okavango Delta concession areas Flow information for Okavango Delta planning is the weblog of the Library of the Harry Oppenheimer Okavango Research Institute The Ngami Times is Ngamiland s weekly newspaper Official Botswana Government site on Moremi Game Reserve inside the Okavango Delta Wild Entrust International Seven Natural Wonders of Africa Discovery Channel Kalahari Flood Flood recession cropping in the molapos of the Okavango Delta Okavango Research Institute Current Okavango water levels weather data and satellite images 1986 Documentary The End of Eden by Rick Lomba Southern African Game Reserves Okavango Delta Retrieved from https en wikipedia org w index php title Okavango Delta amp oldid 1146812788, wikipedia, wiki, book, books, library,

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