The 24th IAHR-APD Congress (24th IAHR-APD Congress)

506 / 2024-05-24 21:22:16

Simplified coupled numerical model for flood modelling in an urban environment

flood modelling,floods,Shallow water,numerical modelling

Subtheme 1: Water-related Hazard and Risk Reduction > Topic 2: Simulation and Forecast of Water Hazard

Hydroclimatic extremes are one of the major aspects of climate change, flooding is one of them. An urban environment has dense population, economic investments and negligible infiltration which make urban flooding a hot concern. Modeling urban flooding is also a challenging task keeping the computational efficiency & hydrodynamic efficiency in mind as a full dynamic model can be computationally expensive while a simplified approach can miss necessary hydrodynamic accuracy. Hence, a coupled model is being developed with a 2D non-inertial framework and a 1D model for different domains of flow. The governing equation for two-dimensional flow is a simplified form of a 2D shallow water equation with all the inertia terms dropped. A finite volume discretization with an implicit time scheme is used to solve the non-inertial governing equation. 1D shallow water equation is used when the flow is showing primarily 1D flow behavior e.g. in a channel or any predefined path. The interaction (coupling) between both the domains of 1D and 2D flow has been modeled with varying boundary conditions.

Results show that the simplified 2D model is computationally efficient and gives satisfactory outcomes, similarly for the 1D model. Although individually both 1D and 2D models were tested and showed satisfactory outcomes, coupling of both needs to be validated with a detailed dataset to establish the robustness of the coupling framework.