This overview paper presents synthetically the main objectives and preliminary results of the RIVES Project (Risque d'Inondation en Ville et Evaluation des Scénarios, funded by the National Research Agency, France). This project is devoted to understanding the need for better hydraulic numerical modeling for flood events in urban areas. It should answer the following question: what is the suitable complexity of the hydraulic numerical model required to fit decision making and planning for unfortunate flood events. The project work is structured on eleven tasks, the most important are dealing respectively with (1) the determination of rainfall scenarios, (2) the experimental study of flow in channel junction, (3) the investigation of the effect of embankments on flow characteristics, (4) the comparison of various 2-D numerical models for simulating free surface flow in urban areas, (5) the coupling of hydraulic surface flow modelling with sewer flow routing, and (6) the assessment of uncertainty in numerical modeling.