Quantification of climate change effects on extreme precipitation used for high resolution hydrologic design

Design of urban drainage structures should include the climatic changes anticipated over the technical lifetime of the system. In Northern Europe climate changes implies increasing occurrences of extreme rainfall. Three approaches to quantify the impact of climate changes on extreme rainfall are studied, all based on output from historical rain series of the present climate and output from Regional Climate Models.

Two models are applied, one being based on an extreme value model, the Partial Duration Series Approach, and the other based on a stochastic rainfall generator model. Finally an approach is based on identification of areas, where the present climate resembles the anticipated future climate for the region in question.

The results indicate that design intensities in Denmark are likely to be increased by 10–50% within the next 100 years. The increase in design intensities depend on the duration and the return period in question.