Evaluating and modelling the impact of extreme events on South African dryland rivers: Cyclone Dando (January 2012)

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In mid January 2012, Cyclone Dando struck southern Africa, leading to widespread heavy rainfall (450-500 mm in 48 hours) & flooding in the Kruger National Park (KNP), eastern South Africa. This flooding occurred just 12 years after the last major catastrophic flooding in the KNP (Jan/Feb 2000), which also caused dramatic river channel & vegetation changes. Using data acquired from light aircraft (photographs, LiDAR) together with field surveying & sediment sampling, this study will exploit a rare opportunity to investigate the flooding, erosion & sedimentation that occurred during the January 2012 event along three rivers in the KNP. The data obtained will be compared with pre-existing data that were collected prior to & following the 2000 flooding in the KNP, & then combined with state-of-the-art computer models to simulate flow characteristics during floods & the longer term response of the rivers to sequences of extreme floods. The aerial, field & modelling results will help to develop new conceptual models of the response of these rivers to extreme events. Such models will have practical application, both for river managers in the KNP & farther afield. Many climate change scenarios predict future increases in the size & frequency of extreme flood events in southern Africa & other dryland regions, & better understanding of the spatial extent of flooding, erosion & sedimentation will contribute to improved flood hazard management & environmental stewardship.