Author:

Keywords:

climate change, hydrology

Abstract:

Changes in climatic variables and land-use evolutions can significantly alter the hydrological behaviour of watersheds. For management purposes it is important to study the hydrological impact of these evolutions in order to define adaptation strategies and plan adaptation measures. Hydrological models may help us assessing the impact of these changes. For this study, in which the complete hydrological system is important, a detailed physically realistic and spatially distributed model code is used. These kinds of models maintain the physical details at a given grid size and consider the distributed nature of hydrological properties such as soil type, slope and land-use. Climate change is likely to have profound effects on the hydrologic cycle through altered precipitation and evapotranspiration. Climate scenarios for Belgium point towards drier conditions during summer periods by reduced rainfall and elevated evaporation. Model results show a decrease of river low flows and a decrease in groundwater levels. These threats of water scarcity may seriously affect drinking water supply, power production, navigation, agricultural practices, the state of aquatic ecosystems,... It will force water resources managers, companies and farmers to adapt. During future winter periods, high flow conditions and associated flood risks might increase as well as decrease by climate change. Also groundwater levels might increase or decrease. This high uncertainty in the hydrological impact has to be taken into account when defining adaptation strategies. Changing land use and land management practices can also alter the hydrological system. Land use change has a direct effect on hydrologic processes through its link with the evapotranspiration regime and the sometimes extreme change in surface runoff. Preliminary model results of future projections of land use for Belgium show that their impact is more limited when compared with the impact of climate scenarios. This study is part of a larger research project about the impact of climate change on high and low flow extremes in Belgium. More information can be obtained at HIC@vlaanderen.be and http://www.kuleuven.be/hydr/CCI-HYDR.htm