Yvon's Fotothing

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The Okavango Delta (or Okavango Swamp), in Botswana, is the world's largest inland delta.

The area was once part of Lake Makgadikgadi, an ancient lake that mostly dried up by the early Holocene, except for seasonal flooding. Today, the Okavango River has no outlet to the sea. Instead, it empties onto the sands of the Kalahari Desert, irrigating 15,000 km² of the desert. Each year some 11 cubic kilometres of water reach the delta. Some of this water reaches further south to Lake Ngami.[1]

The waters of the Okavango Delta are subject to seasonal flooding, which begins about mid-summer in the north and six months later in the south (May/June). The water from the delta is evaporated relatively rapidly by the high temperatures, resulting in a cycle of cresting and dropping water in the south. Islands can disappear completely during the peak flood, then reappear at the end of the season. This process of evaporation was badly understood as late as the early 20th century