Geography of the Okavango Delta

The spectacular result of the Okavango River flowing into the very flat and dry Kalahari Desert.

There is less than 2 metres variation in height across the delta which leads to the formation of the myriad waterways that make up the delta.

Approximately 11 cubic kilometres flow into the delta each year. The water flows continously into the delta and drains the summer (January to February) rainfall from the Angolan highlands. A surge, that flows 1200 kilometres in a month occurs between March and June. It is during this time that the Okavango Delta is at its largest. Rapid transpiration and evaporation occur caused by the high temperatures in the region result in a cycle of rising and falling water levels. One of the only sources of water during the dry period the Okavango Delta attracts thousands of animals creating one of Africa’s greatest concentrations of wildlife.

Once in the delta water is lost to transpiration by plants (60%), evaporation (36%), percolation into aquifer system (2%) and finally 2% flows out into Lake Ngami.

The islands of the delta mostly start as termite mounds (70%) and often have white patches in there centre where the high salt content of the islands collects.

At the centre of the delta is Chief’s Island, the largest island in the delta and formed by a fault line which uplifed a 70 x 15 km wide area. Abundant in animal life it was once reserved as a hunting area for the chief and now forms a safe respite for the resident wildlife when the waters rise.


Formation of the Okavango Delta

A great river that flows not into the sea but into the middle of the southern African continental landmass, the Okavango Delta is more correctly termed an alluvial fan comprising areas that are permanently flooded, seasonally flooded and occasionally flood.

The Okavango Delta has been formed by the Okavango/Kavango River’s flow into the flat and dry Kalahari Desert.


Kalahari Desert

The Kalahari Desert is a large semi-arid sandy savannah in Southern Africa extending 900,000 square kilometres (350,000 sq mi), covering much of Botswana and parts of Namibia and South Africa. As semi-desert, with huge tracts of excellent grazing after good rains, the Kalahari supports more animals and plants than a true desert, such as the Namib Desert to the west.

Kalahari Desert