Okavango Delta and Lake Ngami, Botswana – January 22nd, 201220.4S 22.7E
The Okavango Delta (or Okavango Swamp), in Botswana, is the world’s largest inland delta. It is formed where the Okavango River empties onto a swamp in an endorheic basin in the Kalahari Desert, where most of the water is lost to evaporation and transpiration instead of draining into the sea. Each year approximately 11 cubic kilometres of water irrigate the 15,000 km² area.
The Okavango Delta is produced by seasonal flooding. The Okavango river drains the summer (January–February) rainfall from the Angola highlands and the surge flows 1,200 kilometres in approximately one month. The waters then spread over the 250 km by 150 km area of the delta over the next four months (March–June). The flood peaks between June and August, during Botswana’s dry winter months, when the delta swells to three times its permanent size. Some flood-waters drain into Lake Ngami, which is visible here at the center of the bottom edge.
Lake Ngami is an endorheic lake in Botswana north of the Kalahari Desert. It is seasonally filled by the Taughe River, an affluent of the Okavango River system flowing out of the western side of the Okavango Delta. It is one of the fragmented remnants of the ancient Lake Makgadikgadi. Although the lake has shrunk dramatically beginning from 1890, it remains an important habitat for birds and wildlife, especially in flood years.