2D Numerical Model of Flooding in East Bangkok

Abstract

We propose a new numerical flooding model oriented to water systems comprising large canal networks. Our approach is based on the diffusion wave equation related to a modified version of the so-called “calculations with apparent cross-sectional flow areas.” Our mathematical formulation is based on the analogy of a porous medium characterized by a permeability depending on parameters and directions of the canal network. Next, we combine the “continuous medium” approach with the nonnegative stable numerical algorithm (initially developed for the 1D diffusion wave equation). A numerical solution of our resulting finite-difference equations requires a tangible generalization of the nonnegative algorithm to the case of coupled 2D river-surface flows. Finally, we simulate the flood evolution in the lower Chao-Praya river basin (located in the eastern areas of Bangkok), and we demonstrate the computational efficiency of our proposed method.