Recent changes in flooding in the Xudum distributary of the Okavango Delta and Lake Ngami, Botswana

Abstract

Lake Ngami is the terminal portion of one of the Okavango Delta distributaries, the Xudum. Until 2004, it last received inflow in 1989 and had been dry ever since, with major consequences for the local population and ecology. In 2004, however, the lake received considerable inflow, despite flooding in other distributaries not being unusually extensive. Analysis of inundation maps revealed that, in 1997, a shift occurred in the distribution of floodwaters in the delta, with an increase in the inundated area of the Xudum distributary, whereas that of the neighbouring Thaoge decreased. The nature of the shift is such that the present situation is likely to continue in the future, but no progressive drying or flooding of the two distributaries can be expected other than that caused by climatic variation.