A dynamic bidirectional coupled surface flow model for flood inundation simulation

Chunbo Jiang,Chen Yang,Wangyang Yu,Binliang Lin,Qi Zhou

doi:10.5194/nhess-21-497-2021

Abstract

Abstract. Flood disasters frequently threaten people and property all over the world. Therefore, an effective numerical model is required to predict the impacts of floods. In this study, a dynamic bidirectional coupled hydrologic–hydrodynamic model (DBCM) is developed with the implementation of characteristic wave theory, in which the boundary between these two models can dynamically adapt according to local flow conditions. The proposed model accounts for both mass and momentum transfer on the coupling boundary and was validated via several benchmark tests. The results show that the DBCM can effectively reproduce the process of flood propagation and also account for surface flow interaction between non-inundation and inundation regions. The DBCM was implemented for the floods simulation that occurred at Helin Town located in Chongqing, China, which shows the capability of the model for flood risk early warning and future management.

Highlights

Over the past decades, flood events have frequently occurred, threatening millions of people all over the world
The hydrologic models focus on the water cycle between atmosphere, surface water, and soil in a wide range of space and timescales and involve hydrological processes, such as, precipitation, evaporation, infiltration, etc
The dynamic bidirectional coupled hydrologic– hydrodynamic model (DBCM) model combines a hydrologic model including three sub-models i.e. precipitation, infiltration, and runoff routing, and a hydrodynamic model involving the 2D shallow water equations for the simulations of channel and overland flows. Both models are solved simultaneously within each time step, and the mass and momentum transfer on the coupling boundary are determined based on the characteristic wave propagation theory which is commonly employed in solving Riemann problems (Toro, 2001)

Summary

Introduction

Flood events have frequently occurred, threatening millions of people all over the world. These events are driven by global warming, population growth, rapid urbanization, and climate change (Zhu et al, 2016). Numerous hydrologic and hydrodynamic models have been proposed to simulate the hydrologic processes and flood propagation (Leandro et al, 2014; Li et al, 2013, 2016; Singh et al, 2015; Yu and Duan, 2014a, b). The hydrologic models focus on the water cycle between atmosphere, surface water, and soil in a wide range of space and timescales and involve hydrological processes, such as, precipitation, evaporation, infiltration, etc. It is worth noting that the initial conditions and boundary conditions are significant for the hydrodynamic simulations

Objectives

Methods

Conclusion