Climate change and consequences for water management (KLIWA)

In recent years the signs that a global warming is on its way have significantly increased. On one hand they come from results of global circulation models (GCM) and on the other hand from temperature measurements near the ground. What can be already taken for granted is an increase of the radiation fluxes (IPCC 1996, 2001). In mid-latitudes this will lead to an acceleration of the water circle by intensifying rates of precipitation and evapotranspiration. In a climate change report of the federal government of Germany an increase of the extent and frequency of floods as well as consequences for water availability is forecasted. For water managers the question arise which consequences on the water circle have to be expected. Conclusions and forecasts about climate changes to date refer mainly to the global scale respectively the macro-scale, e.g. Northern Europe due to the model scale of the GCM's. What lacks are regional climate models and regionalization methods for the results of the GCM's. So hard facts like results from model calculations concerning changes in climatic and (geo-) hydrological quantities in river and ground water landscapes as they are found in Southern Germany are yet not available on the regional scale. Water is one of human life's essentials. The aim of water management policy is to secure this essential. Above all knowledge about potential regional changes is therefore a prerequisite to establish a forward looking water management policy based on scientific results. Special interest is laid on the subjects flood danger and therewith flood protection, water availability and therewith water supply, river protection, development and management. In April 1999, the water agencies of the German federal states Baden-Württemberg and Bavaria as well as the German Weather Service (DWD) have agreed on a joint, long-term co-operation for regional studies on the subject "Climate change and con-sequences for water management". For this purpose an action plan was initiated. For the scientific studies the German Weather Service (DWD), the State Institute for Environmental Protection Baden-Wuerttemberg (LfU) and the Bavarian State Agency for Water Management (BLfW) are responsible.