Modeling Urban Flood Dynamics Using High-Resolution Topography and Bathymetry

Abstract:

Flooding is the leading cause of death from natural disasters and poses public health and economic risks to developed and developing cities. In order to better assess these risks, models of flooding need to rely on modern, up-to-date information about urban environments. Approaches based on traditional grids are computationally expensive because of the restriction of the Courant-Friedrichs-Levy condition. This condition introduces a resolution dependency into hydrodynamic models, affecting a number of states such as velocity and water depth, and therefore may impact management and design decisions, becoming a serious weakness in real-time situations.

This research links watershed processes to the urban environment by applying an upscaling method that relies on fine-scale information on elevation, roughness, land cover, and soil moisture. The benefit of this approach is that it reduces resolution dependency, allowing for the calculation of hydrodynamic variables at subgrid scales. This approach negates the need for grid refinement in complex geometries and surface conditions of the urban interface, improving the computational efficiency for simulating and predicting flooding events.