Potential damping of extreme floods in the river Meuse between Ampsin (B) and the Belgian-Dutch border

In the framework of the Interreg IVB project AMICE, hydraulic modelling of floods in the river Meuse was performed by coordinating existing models (Dewals et al. 2012a). The influence of climate change scenarios was incorporated indirectly in the simulations through a transnational hydrological scenario (Drogue et al. 2010; Dewals et al. 2013). For a “wet” future climate, this scenario assumes that the peak discharge Q100 of the 100-year flood would increase by 15 % for the time horizon 2021-2050 and by 30 % for the time horizon 2071-2100. However, the design discharge currently used for planning in the Netherlands is higher than those considered to date in the AMICE project. From this perspective, it becomes relevant to analyse flood scenarios corresponding to a peak discharge above Q100+30 %, referred to hereafter as an “extreme” flood. The aim of the study is to give an appreciation of the potential damping of one extreme flood scenario along the river Meuse between Ampsin (Belgium) and the Belgian-Dutch border (Figure 1). This analysis is based on the hydraulic model WOLF 2D (Erpicum et al. 2010) applied to a coarse grid with simplifications in the schematisation. The hydraulic model WOLF 2D has been already used in several studies to simulate floods (Ernst et al. 2010; Beckers et al. 2013, Bruwier et al. 2015, Detrembleur et al. 2015). The coarsening of the grid for simulating the extreme flood scenario is necessary to preserve the computational efficiency, since both the total flood duration and the inundation extents (hence the number of grid cells) increase considerably between the Q100 + 30 % scenario considered previously and the extreme scenario considered here