Botswana Safari

Summary
The Okavango Delta, in the midst of the Kalahari sands, is Africa's largest and most beautiful oasis. The River Okavango, which rises in the highlands of Angola, never reaches the sea; instead, its mighty waters empty over the sand of the Kalahari Desert. Here the thirstland of the south meets a blue-green wilderness of fresh water, with emerald reedbeds and towering trees.

The Okavango Delta is one of the world’s greatest mysteries – water in a desert! The Kalahari Desert is the largest continuous stretch of sand in the world and within it lays the magnificent Okavango delta, an area that is home to a myriad of animal and bird species. The area is a magnificent expanse of waterways, floodplains, forested islands and lagoons that covers about 18,000 sq kms.

This African oasis originates from a catchment area in Angola called the Cubango River that flows southeast through Namibia as the Kavango River and finally enters Botswana 1000 miles later as the Okavango River. Once here the fate of the River is determined by a series of parallel fault lines that lie deep below the desert surface. Once the river passes over the first fault line, known as the Gomare fault, it splits up into several waterways and channels that spread out and create that fan like pattern that is actually visible from space. When the water finally reaches the final two fault lines, known as the Kunyere and Thamalakane faults, the water is literally dammed up here and disappears into the Kalahari in an almost magical fashion.

The Okavango Delta consists of luxury safari camps that vary in activities from pure game viewing camps to mixed activity camps or pure water based activity camps.

Formation of the Delta
The continent of Africa is currently being split apart by geological processes along the enormous Great Rift Valley which starts north in Ethiopia, passes through Kenya, Uganda and Tanzania. In Tanzania, it divides to cut through Malawi and Mozambique to the east and to the southwest through Zambia's Luangwa Valley and Kariba Valley to Victoria Falls. From Vic Falls, it continues southwest to form the rift-system through the Chobe-Linyanti area to the Okavango Delta at its southwest extremity where it is at its smallest.

This latest opening of the rift forming the Okavango Delta is recent in geological terms - within the last 3 million years. The Delta was formed where this latest portion of the rift cut through the center of the Kalahari sand sheet in a southwesterly direction. The main Okavango rift lies between two parallel fault lines - one at the lower extremity of the Delta passing through Maun (the Thamalakane fault) and the other at the northern edge of the Delta along the line of the Selinda Spillway (the Gomare fault). The area of land between the two southwesterly faults has dropped about 300 metres.

Because the geological tension that is splitting the southern African continent is east-west (instead of NW-SW like the rift), there are a series of minor fault lines at right angles to the major Okavango rift. The most prominent of these minor faults have created a minor rift forming the Okavango "panhandle" or the main Okavango River which empties into the Delta from the Northwest. The area of land to the immediate east of this rift has become slightly elevated forming Chief's Island.

Before the Okavango rift formed, the Okavango River flowed directly through the area where the Okavango Delta is now, through what is now the Lakgadikgadi Pans and probably out to the Indian Ocean via the Limpopo River. When the Thamalakane fault at the lower edge of today's Delta rose up, the Okavango River's flow was blocked and this initiated the Delta's formation.

As the Okavango's rift subsided, it filled up with a mix of windblown sand from the Kalahari and with water-borne sediments carried into it by the waters of the Okavango River until it assumed it's present day form as a major inland alluvial fan. The major ingredients of the Delta today are the flat, dry, infertile Kalahari sand sheet, intersected by a shallow rift valley trough, with a major river flowing into this trough along a minor fault line - the "panhandle". The water and nutrients carried in by the river accumulate in the trough and give rise to the biological productiveness and beauty of today's Okavango Delta.

The Seasons of The Delta
The Okavango receives water from two different sources at two different times of the year. The first is the annual seasonal flood whereby rainwater in the Angolan highlands falls in December and slowly makes its way down to the Delta a couple of months later. The annual rainfall in the highlands of Angola is considerably higher than in Botswana. Rainwater collects within this huge catchment and is channelled down the Okavango river, creating a flood-tide of water which gradually arrives at the Delta. In the upper reaches of the Delta, the river reaches a peak height in February or March, and so the Panhandle is the only area to receive the floods at the same time as the local Delta rains.

As the flood travels down the river bed of the Panhandle, it overflows its banks, revitalizing the swamps and covering the sandbanks. On reaching the fan-shaped Delta, it spreads out overflowing river channels and the banks between clumps of reeds and papyrus, inundating floodplains and slowly raising the water level in lagoons and backwaters. Plants in and around these seasonal swamps thrive once again with the higher ground areas continuing to dry up from lack of rain. The flood's front moves slowly, travelling at speeds of only one kilometre per day - (it takes 4 months for the incoming floods to travel the 250km from Mohembo in northern Botswana to Maun). This is due to both the very shallow gradient (only 65 metres) over this distance and because the water is slowed by the swamp vegetation. Thus, the floodwater reached much of the southern half of the Delta in the middle of the "dry" season.

As the floods subside and the water levels recede, the hot onset of Spring and summer peak with the very hot and dry month of October when dust and airborne sand particles create spectacular sunsets. The second rush of water comes with the local seasonal rains that fall over the Delta in the summer months (December through March). These rains are not like the monsoons of Asia, but rather localized thunderstorms that are usually brief but potent and it usually does not rain two days in a row. The rains usually abate with the onset of April and dry up quickly but leave behind a lush, green carpet of grasses and new plant life.

The Okavango is constantly changing as the water moves through the channels (and with it, the animals that follow the water). The amount of water and when it arrives is all dependant on the amount of rainfall locally and in Angola and it therefore fluctuates on a yearly basis.

The Delta's Water
Only around 2% of the floodwater reaches Maun in a good year. About 95% escapes into the air via evapo-transpiration and a small fraction seeps into the underlying groundwater. Because most of the Delta's water is lost to evapo-transpiration, salts and minerals from the Okavango River are deposited and left behind in the Delta.

The Okavango's water is lowest from November to January when floodwater is confined to the permanent swamps, an area ~ 4,000 sq. km. Flood levels in the Delta are highest between March and September, depending on where one measures. At peak flood, an additional 4,000 to 5,000 sq. km. of seasonal swamp and floodplain are covered by the flood.

The water of the Okavango is clean and pure and it is even safe to drink straight from the flowing channels. The water tends to be stained to the color of weak tea by plant tannins, but this does not affect the purity of the water. The taste of the water may also seem strange to some due to the presence of mineral salts, but again, this does not pose any health hazards. There is no industry in the northern Delta and no agriculture to speak of, so the water coming in is untainted and natural. Additionally, the waterways of the Delta are generally shallow so that light penetration is quite good; this presents very poor conditions for micro-organisms and bacteria to flourish. Finally, the water is continually refreshed through the seasonal cycles of the Delta and as it flows into the channels, it is finely filtered as it passes through hundreds of kilometres of papyrus beds and sandbanks.

The Topography of the Delta
Apart from the permanent channels, the Delta is covered by shallow water, flooded grasslands, backwater swamps, ox-bow lakes and hidden lagoons, mostly interconnected by narrow waterways. The region is a complex of perennial and seasonal swamps and floodplain grasslands. The seasonal swamps are only flooded during high water, when the rivers spill their banks and inundate vast tracts of land. The floodplains are only intermittently covered, depending on rainfall or the direction and intensity of the river's flow that year. Change is the essence of the Okavango's waterways.

Scattered throughout the Okavango Delta are literally millions of islands. Together, they constitute an area equal to that covered by the Delta's water. In all shapes and sizes, they rise just high enough above the surrounding reedbeds and floodplains to support the growth of trees. Ensured of a regular water supply, the woodlands that fringe the islands grow lofty and luxuriant with species that could otherwise never survive on the impoverished Kalahari sands.

There are an estimated 50,000 islands scattered throughout the Delta and they are dazzling in their numbers and variety of form. In the northern permanent swamps they are hillocks so small that there is only room for a single grove of the graceful Date palm, Phoenix reclinata. In the seasonal swamps of the middle Delta they become larger, their perimeters edged by a narrow band of woodland comprising an assortment of lovely trees - Jackalberry, Mangosteen, Knobthorn, and Sycamore Fig.

Each island is unique in the mix of trees it supports. The islands are formed in a variety of ways, most developing from small nuclei. Some begin as elevated feature like termite mounds (see below), or as abandoned channel beds that remain after the water course has been blocked by vegetation (mostly papyrus) and switched to a new channel. Their original shape is usually etched in their eventual form, so islands that started as termite mounds are typically round, while those that formed out of former channel beds tend to be long and sinuous. Other islands - the massive Chief's Island being a notable example - are the result of tectonic activity.

Towards the southern end of the Delta, the islands are quite different. Sometimes called sandveldt tongues, they are extensive areas of Kalahari sand which penetrate deep into the Delta, reminders of the more arid origins of this oasis. The largest, Chief's Island, covers more than 1,000 square kilometers of the central Delta and supports vegetation and animal life more typical of the dry deciduous Kalahari woodlands to the east and north. All the larger islands are fringed by a wide margin of floodplain grassland which is inundated each year by floods only to reappear green and replenished once the waters have passed through.

Most of the smaller islands owe their existence to those ancient builders, the fungus-growing termites. Their activity not only raises patches of land above the general flatness of the Kalahari, but their earth-moving endeavors also enrich the soil, which in turn aids the growth of trees. The termite islands, or 'termitaria', also play an important role in the Delta's pattern of water flow, particularly in the seasonal swamps. Termitaria may be built in the narrow entrances to floodplains or is seasonally flooded lagoons. As they grow, their bases join together so that the land rises and prevents the flow of water into the formerly flooded area. With time, the dried floodplains are colonized by trees. If several islands are closely situated, the continued activity of the termites will cause them to join and a larger islands is formed. In this way, the lands of the Delta and its waterways are constantly changing.

The Delta's Wildlife
The process of renewal and the many habitat types found in the Okavango Delta enable it to support a remarkable number and diversity of life forms, among them 164 species of mammal, more than 400 of bird, 157 of reptile, 84 species of fish and over 5,000 different insects.

The most visibly evident and sought after of the Delta's wildlife are the mammals. Four of the so-called "Big Five" (originally a hunting term used to describe Africa's most dangerous animals and now the prime quarry of the visiting safari game-viewer) are regularly seen by those visiting the Delta, namely lion, leopard, elephant, buffalo. Tragically, as is the case in most safari destinations, the fifth of this group, the rhino, has been relentlessly persecuted, poached to the brink of extinction for its horn. However, early in 2002, Wilderness Safaris (the prime safari camp operator in the Delta) in conjunction with Botswana's Department of Wildlife and National Parks have begun the process of reintroducing White Rhinos on Chief's Island (at Mombo camp). Fifteen White Rhino's have been released so far and they are doing well and are seen regularly around Mombo and Chief's camps. Click the following link to read more about the Safari Updates.

In addition to the Big Five, the Delta's array of mammals includes, among many others, cheetah, giraffe, hippopotamus, many species of antelope, zebra, buffalo, primates such as chacma baboon and vervet monkey, hyenas and crocodiles. Specialties of the Okavango include the Red Lechwe and Sitatunga (both water dependent antelopes), the African Wild Dog (a very rare and endangered animal), Wattled Cranes, and Pel's Fishing Owl.