A 2D finite volume multiblock flow solver applied to flood extension forecasting

ABSTRACT: this paper describes a quasi-3D free surface flow solver,developed for almost ten years at the University of Liege, and its application to flood extension forecasting. Based on the classical SWE, the finite volume numerical model deals with real topography and wetting-drying cells while exactly conserving the water volume. Multiblock options allow local refine-ment of the structured calculation grid and automatic mesh refinement enhances greatly compu-tation time. An additional depth-averaged k-ε type turbulence model increases the potentialities of the solver to represent real complex flows. Following a Regional Government decision, this solver has been officially chosen in 2003 to be used to compute inundation maps on 800 km of the main rivers of the Walloon Region in Belgium with a spatial resolution of 5 x 5 to 2 x 2 me-ters and using high resolution Digital Elevation Models. Results are presented in this paper.