Seen from space, high above Africa, the Okavango Delta resembles a gigantic starburst blossom pressed onto the landscape of northern Botswana, its stem angling southeastward from the Namibian border, its petals of silvery water splayed out for a hundred miles across the Kalahari Basin. It is one of the planet’s great wetlands, a vast splash of life-nurturing channels and lagoons and seasonal ponds amid a severely dry region of the continent.
This delta doesn’t open to the sea. Contained entirely within the basin, it comes to a halt along a southeastern perimeter and disappears into the deep Kalahari sands. It can be thought of as the world’s largest oasis, a wet refuge supporting elephants, hippos, crocodiles, and wild dogs; lechwe and sitatungas and other wetland antelopes; warthogs and buffalo, lions and zebras, and birdlife of wondrous diversity and abundance—not to mention a tourism industry worth hundreds of millions of dollars annually. But from high in space, you won’t see the hippos on their day beds. You won’t see the wild dogs hunkered in shade beneath thorn scrub or the glad expressions on the faces of visitors and local entrepreneurs. Another thing you won’t see is the source of all that water.
The water comes almost entirely from Angola, Botswana’s complicated neighbor, two countries away. It begins in the moist highlands of Angola’s rainy center and flows toward the country’s southeast, quickly in one major drainage, the Cubango, and more slowly in another, the Cuito, where it pools into source lakes; percolates slowly through grassy floodplains, peat deposits, and underlying sand; and seeps into tributaries. The Cuito and Cubango Rivers converge at the southern Angolan border, forming a bigger river, the Okavango, which flows across the Caprivi Strip, a narrow band of Namibia, and into Botswana. On average, 2.5 trillion gallons of water a year flows in.