Urban Stormwater Modeling with Local Inertial Approximation Form of Shallow Water Equations: A Comparative Study

Guoru Huang,Wenjie Chen,Weiqi Wang

doi:10.1007/s13753-021-00368-0

Guoru Huang, Wenjie Chen + Show 1 more

Open Access

https://doi.org/10.1007/s13753-021-00368-0

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Abstract

This study focused on the performance and limitations of the local inertial approximation form model (LIM) of the shallow water equations (SWEs) when applied in urban flood modeling. A numerical scheme of the LIM equations was created using finite volume method with a first-order spatiotemporal Roe Riemann solver. A simplified urban stormwater model (SUSM) considering surface and underground dual drainage system was constructed based on LIM and the US Environmental Protection Agency Storm Water Management Model. Moreover, a complete urban stormwater model (USM) based on the SWEs with the same solution algorithm was used as the evaluation benchmark. Numerical results of the SUSM and USM in a highly urbanized area under four rainfall return periods were analyzed and compared. The results reveal that the performance of the SUSM is highly consistent with that of the USM but with an improvement in computational efficiency of approximately 140%. In terms of the accuracy of the model, the SUSM slightly underestimates the water depth and velocity and is less accurate when dealing with supercritical flow in urban stormwater flood modeling. Overall, the SUSM can produce comparable results to USM with higher computational efficiency, which provides a simplified and alternative method for urban flood modeling.

Highlights

Against the background of climate change and rapid urbanization that result in more frequent extreme rainfall events and changes in the underlying surface, urban floods have become a widely distributed natural hazard worldwide (Kaspersen et al 2017)
This study focused on the performance and limitations of the local inertial approximation form model (LIM) of the shallow water equations (SWEs) when applied in urban flood modeling
We present the most important outcomes of our research on the performance and limitations of the simplified urban stormwater model (SUSM) when applied in urban flood modeling

Summary

Introduction

Against the background of climate change and rapid urbanization that result in more frequent extreme rainfall events and changes in the underlying surface, urban floods have become a widely distributed natural hazard worldwide (Kaspersen et al 2017). As the most important component of urban flood forecasting systems, numerical urban flood simulation technologies have attracted widespread attention in both academic research and engineering application in recent years (Liang et al 2015; Chen et al 2018) because of their excellent computational performance. In order to simulate urban flooding in a realistic manner, urban flood models need to couple the two parts in what is referred to as the dual drainage concept.

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