Umbgrove Lecture Hydrological modelling of the Okavango Delta: A basis for management Speaker: Professor Wolfgang Kinzelbach Institut für Umweltingenieurwissenschaften ETH Zurich Date: Time: Place: November 2, 2009-10-16 15:30 Grote College Zaal Het gebouw Aardwetenschappen Budapestlaan 4, De Uithof, Utrecht Abstract Wolfgang Kinzelbach, Christian Milzow, Lesego Kgotlhang, Peter Bauer-Gottwein Since 1900 about half of the wetland area of the world has vanished together with its immense biodiversity and other ecological services. The pressure on the remaining wetlands is high and conservation and management have to be reconciled in order to preserve their functions. Here the Okavango Delta is considered, which is recognized as a wetland of global importance. The hydrological drivers of the Delta are described and a model is built, which is capable of simulating the annual flooding and drying up of the Delta. It relies heavily on remote sensing data. An aspect related to the hydrology is the salt deposition on islands, which essentially keeps the swamp waters fresh. The mechanism is elucidated using geophysical methods. Finally the model is applied to management options and a climate change scenario. It is argued that the riparians have to be remunerated for custodian services, if the Delta is to thrive in the future.