Hydrodynamics-based assessment of flood losses in an urban district under changing environments

In order to accurately assess the urban flood losses under changing environments, a flood losses assessment framework has been proposed based on a bidirectional coupled 1D/2D hydrodynamic model. Using the proposed flood losses assessment framework and the derived future storm intensity formula under four SSP–RCP emission scenarios, modelling of flood inundation processes in the Qingshan district of Wuhan City was conducted under present climate, intermediate-future climate (2041–2070) and distant-future climate (2071–2100). Flood economic losses and affected population were estimated on the basis of the precise hydrodynamic simulations, inundation depth-loss rate relationship and socioeconomic data in the present and the future under four SSPs scenarios. These results indicate that: as compared with the present climate scenario, the percentage of inundation area on the urban surface would increase by 3.7–14.1% and 8.7–18.2% under the intermediate-future climate and distant-future climate. Flood economic losses from 2030 to 2100 would present increasing trends under four SSPs, which would increase by 0.4–21.7 times compared with the present scenario. The flood-affected population from 2030 to 2100 would present increasing trends under SSP2 and SSP3, and would exhibit increasing-decreasing trends under SSP1 and SSP5, which would show the maximum decrease of 8% and the maximum increase of 552% compared with the present scenario. The results can help to provide a useful insight into the evolution trend of flood losses and the scientific basis for the formulation of disaster mitigation measures.