Enhanced 2D-models as alternative to dual-drainage systems for urban flood simulation

As research in the field of analysing urban flood rainfall events progresses, it is evident that dual-drainage models remain the standard for producing the most realistic results of flood extension and water depth. However, the development of these sophisticated models is contingent upon the availability of comprehensive data sets that can be used to simulate runoff behaviour on the surface and account for hydraulic processes within the sewer network. The aim of this study is to demonstrate that comparable outcomes can be achieved through the modification of 2D surface models, which require less data and are more straightforward to set up. In order to test the efficacy of different methodologies for the enhancement of 2D models, two distinct approaches were implemented in two study areas with disparate rainfall loads in a city in south-west Germany. The results were then compared with those of a 1D/2D model. The findings of this study demonstrate that the methodologies tested are effective in improving the accuracy of 2D models, and that they are capable of producing results that closely align with those of dual-drainage models. • Different approaches for 2D models in urban flood analysis. • 2D models with constant and time varying approach to simulate sewage performance. • Favourable results of 2D models compared to dual-drainage models.