Contribution of land use changes to future flood damage along the river Meuse in the Walloon region

Abstract

Abstract. Managing flood risk in Europe is a critical issue because climate change is expected to increase flood hazard in many european countries. Beside climate change, land use evolution is also a key factor influencing future flood risk. The core contribution of this paper is a new methodology to model residential land use evolution. Based on two climate scenarios ("dry" and "wet"), the method is applied to study the evolution of flood damage by 2100 along the river Meuse. Nine urbanization scenarios were developed: three of them assume a "current trend" land use evolution, leading to a significant urban sprawl, while six others assume a dense urban development, characterized by a higher density and a higher diversity of urban functions in the urbanized areas. Using damage curves, the damage estimation was performed by combining inundation maps for the present and future 100 yr flood with present and future land use maps and specific prices. According to the dry scenario, the flood discharge is expected not to increase. In this case, land use changes increase flood damages by 1-40 %, to C 334-462 million in 2100. In the wet scenario, the relative increase in flood damage is 540-630 %, corresponding to total damages of C 2.1-2.4 billion. In this extreme scenario, the influence of climate on the overall damage is 3-8 times higher than the effect of land use change. However, for seven municipalities along the river Meuse, these two factors have a comparable influence. Consequently, in the "wet" scenario and at the level of the whole Meuse valley in the Walloon region, careful spatial planning would reduce the increase in flood damage by no more than 11-23 %; but, at the level of several municipalities, more sustainable spatial planning would reduce future flood damage to a much greater degree.

Impacts of climate change on future flood damage on the river Meuse, with a distributed uncertainty analysis

“…No evolution in exposure or vulnerability is taken into account. For a thorough discussion on the relative influence of flood hazard evolution and exposure evolution in the same study area and the same long-term horizon (2100), we refer to Beckers et al (2013), whose study includes a sensitivity analysis that considers several land-use evolution scenarios.…”

Assessing the operation rules of a reservoir system based on a detailed modelling chain

“…Besides climate change, continuing urbanization is another key factor influencing future flood risk (Thieken et al, 2014), but this aspect was not included in the present study. Among others, Beckers et al (2013) evaluate the increase in flood damage due to land-use change by 2100 between 540 to 630 % in the wet scenario for the whole Meuse valley in the Walloon Region. More generally, the hydrological coefficients were assumed constant in the long-term simulations, while they should be varied to account for catchment adaptation (e.g.…”

“…It provides detailed spatially distributed results throughout the floodplains (Beckers et al, 2013;Dewals et al, 2011;Ernst et al, 2010).…”

“…The distribution of land-use categories was obtained by combining the localization plan (PLI) and the sector plan (PdS) obtained from the Walloon Region (Beckers et al, 2013). For each land-use category, a damage function provides the rela-tionship between water depth and relative damage.…”

Formation, breaching and flood consequences of a landslide dam near Bujumbura, Burundi

“…This model has been extensively validated and applied for simulating flow induced by dam and dike breaching (Dewals et al, 2011;Roger et al, 2009) as well as for conducting flood risk analysis (Arrault et al, 2016;Beckers et al, 2013;Bruwier et al, 2015;Detrembleur et al, 2015;Ernst et al, 2010). We detail below how friction was parametrized in the hydraulic model, as well as the prescribed boundary conditions and the modelling 155 procedure.…”