The OKAVANGO DELTA (or OKAVANGO GRASSLAND) (formerly spelled Okovango
or Okovanggo) in
The area was once part of
* 1 Geography
* 1.1 Floods * 1.2 Water flow * 1.3 Salt islands * 1.4 Chief’s Island
* 2 Climate
* 3.1 Fish
* 4 People * 5 Molapo\'s * 6 Possible threats * 7 Gallery * 8 See also * 9 References * 10 Sources * 11 External links
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 kilometres in approximately one
month. The waters then spread over the 250 km by 150 km area of the
delta over the next four months (March–June). The high temperature
of the delta causes rapid transpiration and evaporation, resulting in
a cycle of rising and falling water level that was not fully
understood until the early 20th century. The flood peaks between June
and August, during
The delta is very flat, with less than 2 metres variation in height across its 15,000 km2.
Every year, approximately 11 cubic kilometres (11,000,000,000,000 litres) of water flow into the delta. Approximately 60% is consumed through transpiration by plants, 36% by evaporation , 2% percolates into the aquifer system; and 2% flows into Lake Ngami . This turgid outflow means that the delta is unable to flush out the minerals carried by the river and is liable to become increasingly salty and uninhabitable. Water salinity is reduced by salt collecting around plant roots as most of the incoming water is transpired by plants. Peat fires might contribute to deposit salt into layers below the surface. The low salinity of the water also means that the floods do not greatly enrich the floodplain with nutrients.
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.
Approximately 70% of the islands began as termite mounds (often Macrotermes spp.), where a tree then takes root on the mound of earth .
Chief’s Island, the largest island in the delta, was formed by a fault line which uplifted an area over 70 km long and 15 km wide. Historically it was reserved as an exclusive hunting area for the chief. It now provides the core area for much of the resident wildlife when the waters rise.
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 450mm (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, warm nights, and humidity levels fluctuating between 50% and 80%. From March to May, the temperature becomes far more comfortable with a maximum of 30 °C during the day and mild to cool nights. The rains quickly dry up leading into the dry, cold winter months of June to August. Daytime temperatures at this time of year are mild to warm, but the temperature begins to fall after sunset. Nights can be surprisingly cold in the Delta, with temperatures barely above freezing.
September to November sees 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 and the dryness is only occasionally broken by a sudden cloudburst.
A South African cheetah silhouetted against a sunset in Okavango Delta.
The Okavango delta is both a permanent and seasonal home to a wide variety of wildlife which is now a popular tourist attraction.
African bush elephant
The majority of the estimated 200,000 large mammals in and around the delta are not year-round residents. They leave with the summer rains to find renewed fields of grass to graze on and trees to browse, then make their way back as winter approaches. Large herds of buffalo and elephant total about 30,000 beasts.
Small gathering of lechwe antelopes,
The most populous large mammal is the lechwe antelope, with more than 60,000. It is a little larger than an impala with elongated hooves and a water repellent substance on their legs that enables rapid movement through knee deep water. They graze on aquatic plants and, like the waterbuck , take to water when threatened by predators. Only the males have horns.
Papyrus and reed rafts make up a large part of the Okavango's vegetation. During the flood season they float well above the sandy river bed with roots dangling free in the water. This gap between bed and roots is utilised as shelter by crocodiles. 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. In the Delta, because of the clean waters of the Okavango , there is almost no mud and the river’s load consists almost entirely of sand. 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. The reason for that is that they are actually the natural banks
of old river channels which over time 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
Hambukushu guide poles his makoro on Delta floodwaters
The Bugakhwe and anikwhe are
The Wayeyi have inhabited the area around
Seronga as well as the
southern Delta around Maun , and a few Wayeyi 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
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 the years 1974 to 1978 the floodings were more intensive than normal and flood recession cropping was not possible, so that severe food and fodder shortages occurred. In response, the Molapo Development Project was initiated. It protected the molapo's with bunds to control the flooding and prevent severe flooding. The bunds are provided with sluice gates so that the stored water can be released and flood recession cropping can start.
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. Other threats include
local human encroachment and regional extraction of water in both
The award-winning 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 vividly portrays this and his lobbying on behalf of the Delta helped to preserve its integrity.
Elephants in the
A buffalo herd in the southern part of the Okavango Delta. *
Water lilies in the delta *
Girl gathering food in the
Waiting for the hippos in the delta *
Hippos as seen from a small boat in the Okavango *
A pair of saddle-billed storks *
Astronaut photograph of the delta *
Sunset in the Okavango
* Wetlands portal
This article includes a list of references , but ITS SOURCES REMAIN UNCLEAR because it has INSUFFICIENT INLINE CITATIONS . Please help to improve this article by introducing more precise citations. (February 2008) (Learn how and when to remove this template message )
* ^ "Okavango Delta". Retrieved 25 July 2017. * ^ Cecil Keen. 1997 * ^ http://sevennatural