Africa facts zone presents one of the Seven Wonders of Africa, The Okavango Delta. Okavango delta is a unique pulsing wetland. More correctly an alluvial fan, the delta covers between 6 and 15 000 square kilometres of Kalahari Desert in northern Botswana and owes its existence to the Okavango (Kavango) River which flows from the Angolan highlands, across Namibia’s Caprivi Strip and into the harsh Kalahari Desert.
An oasis within the Kalahari Desert, the Okavango Delta is one of the great wildlife refuges of Africa. The pulsing nature of the wetland leads to strikingly different landscapes with both permanent and seasonal delta environments.
The Okavango Delta is a vast and varied ecosystem created as the Okavango River flows into the Kalahari desert in Botswana. Rich in wildlife, this World Heritage Site is a sanctuary to some of the world’s most endangered animals and birds.
About the Okavango Delta in Botswana
The Okavango Delta lies in the north west of Botswana. Part of the Great East African Rift Valley system, the Okavango Delta is formed as the Okavango River flows into the Kalahari Desert from the Angolan highlands, creating a unique wetland, a huge oasis that sets the region’s rhythm with its annual pulses.
There is less than 2 metres variation in height across the entire 250 kilometre length of the Delta: it is this almost complete absence of topographical relief that leads to the formation of the myriad waterways that make up the Delta. The vast quantities of water flowing into an almost flat desert results in a maze of winding channels, oxbow lakes, islands and floodplains. The water is finally stopped in its lugubrious progress by a fault line. It really is a landscape unlike any other.
Approximately 11 cubic kilometres flow into the Delta each year. The water flows continuously into the Delta and drains the summer (January to February) rainfall from the Angolan highlands. A surge, that flows a staggering 1200 kilometres in a month, occurs in Botswana between March and June. It is during this time that the Okavango Delta is at its largest. The high temperatures in the region cause rapid transpiration and evaporation which results in a cycle of rising and falling water levels.
As one of the only sources of water during the dry period, the Okavango Delta attracts thousands of animals and one of Africa’s greatest concentrations of wildlife. The true miracle of this oasis in the desert is that the flood waters appear just when the rainy season has ended and water and food are becoming scarce in the region. The waters of the annual flood truly are waters of life.
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 their centre where the high salt content of the islands collects. This process causes the islands to become toxic and trees die off in the centre.
At the centre of the Delta is Chief’s Island, the largest island in the Delta. Chief’s Island was formed by a fault line which uplifted 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.
The Okavango Delta is formed when a great river 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, seasonally and occasionally flooded.
With sources in the plan alto highlands 1200 metres above sea level in Angola, the Okavango Delta is the culmination of a river system that has its catchment areas in Angola, flows through Namibia and then into Botswana where various processes govern the distribution across the alluvial fan.
These processes are both physical, dependent on slope, sedimentation, faults and channels carved long ago in the Kalahari sands and also biological, shaped by hippopotami pushing their way along the waterways, termites constructing their intricate mounds and the natural growth of papyrus. With so many factors shaping the Okavango, it is not surprising that the flow of water is variable and unpredictable.
The Delta consists of a multitude of main channels, smaller tributaries and lagoons as well as floodplains, islands and mainland areas. The watercourses are always changing due to annual flooding as well as a combination of sediment transport, seismic activity, the construction of termite mounds, the continual opening up of new channels by feeding hippopotami and the closing of others by new vegetation growth.
The wildlife of the Okavango Delta is varied and plentiful thanks to the rich ecosystems and protection. The Okavango Delta supports large concentrations of animals on both a permanent and seasonal basis. Through careful wildlife management it has become perhaps one of the best places to see wildlife in Africa.
There is a dynamic seasonal shift of animals between the arid region that surrounds the delta and the Okavango Delta itself. During the wet season most large animals move away from the delta to take advantage of the lush grazing that surrounds it. As this grazing begins to die in the winter animals move back to the delta.
Wildlife of the Okavango Delta includes a myriad of species including African Bush Elephant, African Buffalo, Hippopotamus, Lechwe, Topi, Blue Wildebeest, Giraffe, Nile crocodile, Lion, Cheetah, Leopard, Brown Hyena, Spotted Hyena, Greater Kudu, Sable Antelope, Black Rhinoceros, White Rhinoceros, Plains Zebra, Warthog and Chacma Baboon. Notably the endangered African Wild Dog still survives within the Okavango Delta and exhibits one of the richest pack densities in Africa.
In addition to the large animals the wildlife of the Okavango Delta includes over 500 species of birds and 85 recorded species of fish including Tigerfish, Tilapia and Catfish.
The Okavango Delta would not exist as we know it without the help of a number of keystone species which help to shape the environment and habitats in and around the Delta. These eco-system engineers include the elephant, hippo and termites.
When to Visit
The Okavango is one of the most dynamic safari destinations in Africa, making it all the more alluring. Every season is different and indeed the each year can be different too. The Okavango is a year round destination and with careful planning based on a deep understanding of this complex environment you can enjoy an excellent safari at any time of year.
The best time to visit will depend on your particular interests. Traditionally the dry season, when paradoxically the Okavango waters are highest, offers the best game viewing as the animals flock to the waters from the dry hinterland. This is also when many camps can offer water activities. However there are exceptions, October for example is the driest and hottest month and delivers superb game viewing but usually has low water levels.
The shoulder months (mid-season) have much to recommend them too. November brings the first life giving rains and the land springs to life, a bright green carpet over the plains appears and the calving season for many antelope, such as impala, begins.
If you are a birder the best time to visit is generally during the summer months when the Okavango is bursting with resident and migratory birds – the air full of song and flashes of colour. That said, some of the heronries are best visited later in the year, so this too will depend on your personal preference. Excellent game viewing can be enjoyed in the summer months too, in the right areas with good resident game and permanent water channels. These months also see the longest migration in Africa as tens of thousands of zebra migrate to the salt pans, a stunning sight.
Every month delivers a different experience and with careful planning you can have a superb safari in the Okavango at any time of year.
The ecological importance and ‘Outstanding Universal Value’ of the Okavango Delta has been recognised by UNESCO and the RAMSAR Convention. The Okavango Delta was designated a Wetland of International Importance in 1996 and a World Heritage Site in 2016.
Together these international bodies aim to protect the future of this unique and sensitive eco-system.