Eighty percent of Botswana's landmass is made up of Kalahari sand deposit and the topography averages around 950 meters above sea level. The highest point in Botswana is a mere 1400m above sea level indicating a very flat and dry country. So what is it about Botswana that it possesses some of Africa's finest wilderness areas? The answer is rivers - and strange rivers at that!
By Leigh Kemp
Rivers and Swamps
This desert-locked country is blessed with two rivers that flow into the country in the far north - both rivers forming some of the most spectacular wilderness areas on earth. The two rivers are the Okavango which forms the iconic Okavango Delta and the Kwando
which is the forerunner for the Linyanti swamps and the Chobe River where Africa's greatest elephant populations are found.
The Okavango Delta is the remnant of an ancient inland lake that once covered most of the interior of southern Africa and was fed by the Zambezi River before tectonic activity forced it to change its course. The Okavango River rises in the highlands of Angola and flows more than 1500km before spilling into the delta in the heart of the Kalahari Desert.
The Okavango Delta is a collection of large and small islands, channels and floodplains, and various vegetation types such as mopane woodland and floodplain savanna. The islands are mostly fringed by thick riverine woodland including spectacular trees such as African ebony, sausage trees and various fig species.
The seasonal floodplains provide wildlife with rich grazing during the times when the water has subsided. The water is at its lowest at the beginning of the rainy season and with the arrival of the rains the floodplains green up.
The Kwando River also rises in the Angolan highlands and soon after entering Botswana it turns east, forming the Linyanti Swamp
in its bend, before flowing into Lake Liambezi and becoming the Chobe River.
The Savuti Channel flows out of the Linyanti and wends its way through the arid woodlands north of the delta before emptying into the Savuti Marsh nearly 100km away in the Mababe Depression.
The Savuti has a unique history in that it has a tendency to dry up for years before flowing again. This uncertainty is now known to be caused by tectonic activity - the source of the channel becomes blocked thus stopping the flow and then reopens again after some years. The channel dried up in 1981 - and only last year did it start flowing again.
It is not certain when the channel will reach the marsh again but what is certain is that the eco-system of Botswana is about to be drastically changed. From an area that supports wildlife in masses during the rainy season to a place that is a haven for wildlife in the dry season interesting times lie ahead.
The Savuti marsh today is grassland and is embraced predominantly by mopane woodland and the Mababe Depression is acacia savannah
. This is about to change with the Savuti Channel beginning to flow again.
Deserts and Ancient Lakes
South of the great northern waterways are the more arid reaches of the Kalahari where water is at a premium. The Makgadikgadi Salt Pans are the remnant of an ancient inland lake that was fed by the Zambezi River before tectonic forces changed the course of the river.
The pans today, the largest in the world, are dry except for some seasons of exceptional rain when they may partially fill. The edges of the pans are dominated by short grasses that attract herbivores in numbers during the rainy season. The Central Kalahari is covered by arid savannah grassland and woodland. The ancient riverbeds are a haven for wildlife in the wet season where the lush grasses attract herbivores in their tens of thousands.
From this wide range of eco-systems comes Botswana's rich wildlife heritage and fascinating animal behaviour.