Development of an Urban Flood Forecast Model Using Lumped Pipe Networks

Typical urban flood simulation is conducted using physical models such as the 1D storm water analysis model and 2D inundation analysis model. Although 2D inundation analysis can predict flow velocity, inundation depth, and inundation area throughout an inundated urban area, it is difficult for it to produce a near real-time urban flood forecast for a metropolitan area such as Seoul. In this study, a physical urban flood forecast model was developed using lumped pipe networks to produce a near real-time urban inundation forecast. The dense pipe networks within a drainage basin were simplified as a single conceptual lumped pipe that has drainage and storage functions, and new pipe networks were constructed using lumped pipe networks. The model was applied to the August 2018 storm events in Seoul and showed a prediction accuracy of 0.71. The results demonstrated that the model can obviate the limitations of the near real-time operation of existing physical flood forecasting models to yield useful information for urban flood response, though showing room for improvement.