Kalahari Desert
Kalahari Desert is an arid region on the interior plateau of southern Africa, occupying central and southwestern Botswana and parts of west central South Africa and eastern Namibia. The desert covers an area of about 260,000 sq km (100,000 sq mi). The Kalahari is part of a large sand basin stretching into Angola and Zambia in the north, through Botswana into Zimbabwe in the east, south to the Orange River in South Africa, and west to the highlands of Namibia. This basin has a total surface area of about 930,000 sq km (360,000 sq mi). The name Kalahari is derived from the Tswana word Kgalagadi, meaning "the great thirst."
Land and Resources
The Kalahari has a semiarid climate, and droughts are frequent. The
region receives about 200 mm (8 in) of precipitation a year, mainly
between the months of October and May. The rainfall pattern is highly
variable, however, and precipitation can fluctuate by more than 100
percent between years. Daytime temperatures range between 35° to 45°C
(95° to 113°F) from October to March, the hottest months, and can drop
below freezing between June and August.
The only permanent surface water in or around the Kalahari is the Boteti River. The Boteti flows out of the Okavango Delta, an extensive swampy region at the northern edge of the Kalahari Desert in northern Botswana. Heavy rains in central Angola cause periodic flooding of the delta, and the Boteti carries the overflow east into Lake Xau and the Makgadikgadi Pan on the northeastern fringe of the desert. Other channels carry water south into Lake Ngami.
Elsewhere in the desert,
short-lived networks of streams and rivers flow after rains.
Subterranean water can be found below the temporary watercourses. These
streams flow into depressions in the desert, known as pans. Pans vary
in size from a few meters to tens of kilometers in diameter, and
provide temporary or semi permanent sources of surface water.
The African countries lying on the desert fringes include: