540
widely believed to be the world’s largest inland
delta, it is, in fact, not. In Africa alone, there are
two larger similar geological features, namely,
the Sudd on the Nile in South Sudan and the
Inner Niger Delta in Mali.
24.4.1 Geography
24.4.1.1 Floods
The Okavango is produced by seasonal fl ooding.
The Okavango River drains the summer (January–
February) rainfall from the Angola highlands,
and the surge fl ows 1,200 km in 1 month
(approx.). The water then spreads over the
250 km by 150 km dimension of the delta over
the next 4 months (March–June). The high
temperature of the delta causes rapid transpiration and evaporation, resulting in a cycle of rising
and falling water level that was not fully
understood until the early twentieth century. The
fl ood peaks between June and August, during
Botswana’s dry winter months, make the delta
swells to three times its permanent size. This
attracts animals from kilometres around and creating one of Africa’s greatest concentrations of
Fig. 24.3 Okavango Delta
24 Wetlands of Africa