Three-dimensional urban flood inundation simulation based on digital aerial photogrammetry

Intense storm surge can lead to severe coastal floods. Flood inundation simulation is useful to identify areas that are most vulnerable to severe storm surges and to address potential flooding hazards. In this paper, both 2D and 3D hydrodynamic models are built separately to quantify the flood danger to a coastal city. A digital city model is generated by integrating building information modeling (BIM) and geographic information systems (GIS) technology based on digital aerial photogrammetry for the 3D hydrodynamic model. The results reveal that 2D hydrodynamic assumptions and approximations weaken if the vertical fluctuations are enormous, especially in urban environments. In comparison, a 3D model coupled with high-resolution topographic data can provide a more realistic and accurate result for the complex flow field. Furthermore, a comparison between using the digital city model and a standard digital elevation model (DEM) in a 3D model has been conducted. The flood inundation is simulated step-wise using the standard DEM, while the wave front propagates in a more realistic manner based on high-resolution topography data. Thus, a 3D hydrodynamic model coupled with the digital city model is recommended for urban flood simulation, which is promising to improve the ability of flood prediction and prevention.