Simulating Climate Impacts on Water Resources: Experience from the Okavango River, Southern Africa

The Okavango River is one of the largest and most important rivers in Southern Africa. The river rises in Angola, a country that has just emerged from a civil war of three decades. The annual flood pulse of the river feeds the Okavanoo Delta: one of the most valuable environmental resources of the African continent. The Okavango River water and its ecosystem resources are critically important sources of livelihoods in the basin. Pressures from livelihoods and development are already impacting on the environment and are likely to increase. Moreover, future development will occur against the background of climate variability and change. This chapter describes research conducted under the EU-funded project 'Water and Ecosystem Resources in Regional Development' (WERRD), whose aims included development of scenario modelling as a tool for integrated water resource management in the Okavango River basin. The impact of climate change scenarios on downstream river flow and flooding in the Okavango Delta are simulated using a suite of hydrological models. The simulated impacts of climate change are sensitive to the choice of GCM and the IPCC SIZES greenhouse gas (GHG) emission scenarios. The simulated impacts are considerable larger that those of the selected development scenarios although the uncertainty in the magnitude of future changes remains high.