Detailed 2D numerical modeling for flood extension forecasting

In the global framework of recurrent large flood events all over the world and in Europein particular, relevant and detailed inundation maps represent a tool of prime interest fordecision makers, emergency services or insurance companies. In 2003 in Belgium, following a Regional Government decision, hydraulic 2D numerical modelling has been chosen to compute inundation maps on 800 km of the main rivers of the Walloon Region, using high resolution Digital Elevation Models. The present paper covers a detailed description of the state-of-the-art 2D finite volume model used to fulfil this task. As a part of this project, the model has been extensively validated by comparisons with observations during recent real flood events. It shows a very good agreement with observations, in particular regarding free surface elevations.
Following this first step toward flood management, the Belgian National project “ADAPT” is presented. It aims to develop an efficient decision support tool for the integrated assessment ofadaptation measures against climate change induced flooding. In this scope, the model has been applied to predict inundations induced by floods, taking into account different climate change scenarios. The results of these simulations serve as input for a subsequent economic, social and ecological analysis by other scientific research teams.