Description of the application

The question of a possible climatic change and the associated effects on human society is presently a major topic of public discussion. The observed weather phenomena of recent years, in particular precipitation events, make clear that also water management must adapt to changes occurring in the runoff behaviour. In order to investigate these implications, the states of Baden-Wuerttemberg and Bavaria as well as the German weather service initiated the joint project KLIWA (climatic change and consequences for water management) in 1999, which was to examine the influence of climatic scenarios. In this joint project so-called climatic factors were determined with which regionally dependent peak discharge quantities for different occurrence probabilities needed to be increased, in order to be able to consider the climatic changes. This contribution points out how climatic change affects, in view of further discharge processes of flood events, flood security as well as potential flood damages. Within the context of a pilot study at the Institute for Water and Water Resources Management (IWG), the effects of the modified discharge characteristics were examined more closely for the barrage of Gundelsheim at the river Neckar. The section extends from the lock at Gundelsheim (Neckar km 93.8) to the weir at Neckarsulm (Neckar km 107.15). The increase of the peak discharges leads, in particular for frequent flood events, to a significant increase in the water levels and thus to a substantial increase in potential flood damages. For an event with a return period of 20 years the climate-change factor increases water levels by more than 1 m, which leads to a 9-fold increase in flood damages. Even with a 100-year flood event with only a relatively small proportional change in the discharge volumes of 15%, an increase of 60 cm in flood depths is expected which can potentially cause a doubling in flood damages.

Lessons learned

The consequences of a possible change in climate conditions on the design of flood defence installations or the "re-valuation" of the degree of flood protection becomes significant when the changes in the peak discharges are calculated back to the associated return periods.

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Last modified: Sept. 13, 2016, 4:22 a.m.