Analysis and modeling of flooding in urban drainage systems

The European research project in the EUREKA framework, RisUrSim (Σ!2255) is presented. The project consortium includes industrial mathematics and water engineering research institutes, municipal drainage works as well as an insurance company. The overall objective has been the development of an integrated planning and management tool to allow cost effective management for urban drainage systems. The paper outlines the regulatory background of European Standard EN 752 defining flood frequency as the one hydraulic performance criterion. The phenomenon of urban flooding caused by surcharged sewer systems in urban drainage systems is analyzed leading to the necessity of dual drainage modeling. A detailed dual drainage simulation model is described based upon hydraulic flow routing procedures for surface flow and pipe flow. Special consideration is given to the interaction between surface and sewer flow in order to most accurately compute water levels above ground as a basis for further assessment of possible damage costs. The model application is presented for small case study in terms of data needs, model verification and first simulation results.