Climate models project for Germany a significant change of regional climates, including increased temperatures and changing precipitation properties that point to an increase in heavy rainfall. Road drainage systems therefore have a two-fold challenge ahead: On the one hand heavier rainfall poses the risk of hydraulic overload to the drainage facilities. On the other hand, long dry spells can lead to operational problems, e.g. if the vegetation in planted soil filters is damaged by drought stress.
So far, the aim of this research project was to monitor the current dimensioning approach of road drainage systems according to the „Guidelines for Road Design – Part: Road Drainage“ (RAS-Ew) and the „Guidelines for structural measures for roads in water reserve zones“ (RiStWag).
By assessing and further processing of several computation runs of the regional climate model CLM (Climate Local Model) for the near future (up to 2050) and the distant future (until 2100), the project has provided some knowledge as to whether the current dimensioning approaches are sufficient in terms of hydraulic performance and drainage safety whilst re-taining soil and water protection as well as in terms of constructive designing or whether appropriate adaptation measures would be necessary. The findings gained from this research should be considered for the revision of the RAS-Ew and the RiStWag.