SATELLITE BASED RAINFALL DATA AND FLOODING OVER THE OKAVANGO RIVER BASIN IN SOUTHERN AFRICA. Dominic Kniveton 1 , Russell Layberry 1 , Lotta Andersson 2 , Thomas Gumbricht 4 , Denis Hughes 2 , Susan Ringrose 4 , Hubert Savenije 5 , Martin Todd 6 , Julie Wilk 2 , Piotr Wolski 4 1 School of Chemistry Physics and Environmental Science, University of Sussex, Falmer, Brighton, UK 2 Dept. Water & Environmental Studies, Linköping University. S-58183 Linköping. Sweden 3 Institute for Water Research, Rhodes University, P O Box 94, Grahamstown, 6140 South Africa 4 HOORC University of Botswana, P/Bag 285, Maun, Botswana 5 IHE, P.O. BOX 3015 Westvest 7, 2601 DA Delft, Netherlands 6 University College of London, 26 Bedford Way, WC1N0AP, London, UK Abstract As part of the EU-funded project “Water and Ecosystem Resources in Regional Development – Balancing Societal Needs and Wants and Natural Resources Systems Sustainability in International River Basin Systems“ (WERRD) research has been carried out aiming to improve and develop scientific methods that will facilitate the understanding of fluctuations of hydrological and ecosystem variables and likely human-induced trends concerning key characteristics of the Okavango River Basin in Southern Africa. The Okavango river basin spans the three riparian states of Angola, Namibia and Botswana ending in a large (22,000 km 2 ) alluvial fan subject to annual flooding. The extent of flooding varies seasonally from low in December (3000-5000 km 2 , depending on year) to high in August (6000-12000 km 2 ). Water for the delta is primarily delivered as rainfall, upstream over Angola. Due to the 20-year civil war in Angola there is little recent raingauge data with which to model the hydrology of the river. To overcome this data gap a 10-year database of daily satellite derived rainfall data at 10km spatial resolution has been produced using data from METEOSAT, Special Sensor 1