Scenario-based urban flood forecast with flood inundation map

Abstract

The objective of this study is to introduce how to apply the urban flood forecast with numerous flood inundation map scenario in Korea. In modeling of urban flood, drainage networks 1D model like SWMM (Storm Water Management Model) used to analysis stormwater runoff within drainage pipe system and 2D surface model used to simulate inundation area and depth. This 1D-2D model (drainage network 1D coupled to 2D surface model) is used to make the inundation map of urban flood. The accuracy of the 2D model is highly dependent of the input data resolution. The cell by cell running on these high surface resolution need to be required more computation time. Thus, the 1D-2D models have some limitations in using operational real-time forecast. In this sense, the scenario-based approach can be a good alternative method to forecast urban flood. The flood inundation maps would be completed with 320 rainfall scenarios which are finely divided according to rainfall intensity and duration on the basis of design rainfall. The forecast process is very simple if we use pre-existing scenarios. We use a predicted radar rainfall as input for simulated scenario selection, and then selected inundation map would be serviced to people. In this study, the current results for the scenario-based urban flood forecast with flood inundation map are demonstrated.