Flood Events in the Rhine Basin: Genesis,Influences and Mitigation

The paper analyses the hydrological regime of the Rhine catchment,the genesis of recent floods,and recommends some research and practical activities to mitigate flood damage. The catchment of the Rhine River can be divided into four main subcatchments: the alpine region with the Aare River as its main tributary and downstream the lower mountain regions of the tributaries Neckar, Main and Moselle. These four basins generate very different hydrographs. Due to the geographical conditions, the average discharge maximums shift from summer to winter downstream the Rhine. Moreover, the spatial and temporalprecipitation patterns of each river have a strong influence on the individual flood events. Some recent extraordinary floods are used to illustrate the parameters that have influenced these events.A strong relationship between recent climate change observationsand the occurrence of flood levels cannot be proven. However, the consequences of human interventions and the resulting changes to the river system (the Rhine and its tributaries) for the hydrograph can be quantified precisely.The influences of different land-use and climatic scenarios on flood conditions in the Rhine basin have not yet been separately identified. Thus, the Dutch-German project LAHoR was established. The primary aim of this project is to giveadvice for the ``Action Plan on Flood Defence' of the International Commission for the Protection of the Rhine (IKSR). In this plan a multidisciplinary approach to mitigating floods is suggested.It is anticipated that the plan willgenerate synergistic effects between flood prevention, water management, regional planning, agriculture, forestry and ecological demands.