Modelling of urban flooding due to Yangtze River dike break

Wang, Xin; Cao, Zhixian; Pender, Gareth; Tan, Guojun

doi:10.1680/wama.900074

Cited by 3 publications

(4 citation statements)

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“…Funke et al (2011) and Tsakiris and Bellos (2014) conducted research on the treatment of wetting and drying. Research has also been carried out on the trade-offs between accuracy and computational efficiency (Fewtrell et al, 2008;Gallegos et al, 2009;Wang et al, 2010). Gallegos et al (2009) used an unstructured grid, Godunov-type, finite volume model to simulate a dam-break flooding event in an urban residential area and validated their model with high-resolution data.…”

Section: Introductionmentioning

confidence: 99%

Multi-Mode Surface Generalization Supports a Detailed Urban Flooding Simulation Model

Yao

Liu

et al. 2021

Front. Earth Sci.

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With the aim of achieving high precision and high efficiency, recent research on hydraulic flood models has tended to focus on the algorithms for solving the shallow water equations of Saint-Venant. While development of the algorithms will help to improve the simulation precision and the solving of specific problems, the other influential factor in flood risk modeling is the precision and reasonable generalization of the data. This is even more important for increasing the model’s computational accuracy and efficiency but is frequently undervalued. Frequent rainstorm waterlogging is having a serious impact on China’s large cities. Early warning of waterlogging risk following a rainstorm forecast is an effective method for preventing or reducing potential losses. Concrete waterlogging information including locations, depth, and process is essential for early warnings. This paper focuses on the influence of data precision and reasonable generalization on an urban flooding model. A detailed hydraulic urban flooding model characterized by detailed data processing and component coupling can help to provide advance information. In Beijing city, road networks, overpasses, and buildings are so highly concentrated that rainstorms easily result in waterlogging in low-lying locations. Therefore, partial microrelief is the determinate factor in waterlogging simulation. This paper shows that multi-mode surface data generalization and detailed model coupling support a perfect simulation of a Beijing urban flooding model. The influence of buildings, roads, and overpasses on surface water flow was carefully considered based on the innovative aspect of a fine generalization of partial microrelief. One novelty is the simulation of the whole overland flow from the beginning of rainfall to mesh, not only from manhole overflow, because the waterlogging is caused mainly by initial surface water runoff rather than by manhole overflow. A second novelty is the use of a new kind of coupling mode based on physical mechanisms between surface and pipe models. Here, rain perforated strainers instead of manholes play a role as flow exchange points between pipe and surface. This coupling mode is much closer to the real world. Based on a detailed Beijing urban flooding model, a scenarios library of typical rainfall events and corresponding waterlogging results was constructed. Several years of practice have demonstrated that a rich library of scenarios can be used effectively for the quick identification and early warning of waterlogging risk for a forecast rainfall. Test results show that multi-mode surface generalization is effective in improving outcomes and useful for scientific decision making in controlling urban waterlogging.

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Section: Introductionmentioning

confidence: 99%

Multi-Mode Surface Generalization Supports a Detailed Urban Flooding Simulation Model

Yao

Liu

et al. 2021

Front. Earth Sci.

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“…The papers in this issue illustrate some of the range of modelling problems that currently arise in water management.The first paper in this issue by Wang et al (2011) on modelling of urban flooding due to a dike break adds to the literature on flood risk assessment. The importance of urban flood risk to society has been highlighted by recent floods in urban areas.…”

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confidence: 99%

“…Modelling flood spreading in urban areas presents many challenges due to the nature of the topography. In this issue, the paper by Wang et al (2011) demonstrates the importance of mesh resolution and the estimation of hydraulic roughness on the model predictions for such problems.The authors of the first paper illustrate the importance of accurate predictions of hydraulic roughness for flow modelling. Our ability to predict channel roughness has improved significantly recently; see for example, McGahey et al (2009).…”

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Editorial

Bettess¹

2011

Proceedings of the Institution of Civil Engineers - Water Manag

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The models used to describe most water systems are complex and the development of water management as a discipline is a history of the development of modelling techniques. The papers in this issue illustrate some of the range of modelling problems that currently arise in water management.The first paper in this issue by Wang et al. (2011) on modelling of urban flooding due to a dike break adds to the literature on flood risk assessment. The importance of urban flood risk to society has been highlighted by recent floods in urban areas. It is difficult to overestimate the economic and social impact of such floods. In the UK, floods such as that in Carlisle in 2005 are still being studied (Horritt et al., 2010) because of their impact and as a means to develop and refine modelling techniques. As urban areas develop and with the expected future climate change it is likely that the risk of urban flooding will increase. A framework for such flood risk assessment was described by Sayers et al. (2008). One of the key problems of implementation, however, is to develop fast models of flood spreading or inundation over an irregular topography (Lamb et al., 2009 andWang et al., 2010). Modelling flood spreading in urban areas presents many challenges due to the nature of the topography. In this issue, the paper by Wang et al. (2011) demonstrates the importance of mesh resolution and the estimation of hydraulic roughness on the model predictions for such problems.The authors of the first paper illustrate the importance of accurate predictions of hydraulic roughness for flow modelling. Our ability to predict channel roughness has improved significantly recently; see for example, McGahey et al. (2009). Their approach relies, however, on having descriptions of the contributions to hydraulic roughness from different physical processes. The second paper in this issue (Kumar, 2011) adds to this information by providing a description of hydraulic roughness in mobile bed channels. The paper demonstrates the benefits that can be derived from collecting and using data that already exists in the literature. The paper represents an application of neural networks to a topic in water management. Although initially very suspicious of the use of neural networks over more traditional approaches, I was convinced after seeing a demonstration that neural networks can provide a better approximation to data than methods based on assuming some functional form for the relationship between the variables involved. Therefore although the use of neural networks may not seem to add to our understanding of the fundamental physics of a problem, they can provide improved tools for prediction.The next paper by Kangrang et al. (2011) represents an interesting application of the optimisation technique simulated annealing to a longstanding problem of the optimum use of reservoirs. The method of simulated annealing may be particularly suited to global optimisation problems in water management where noisy data makes the application of other optimisation techniq...

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Application of a Three-Dimensional Unstructured-Mesh Finite-Element Flooding Model and Comparison with Two-Dimensional Approaches

Zhang

Feng

Maksimović

et al. 2015

Water Resour Manage

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. AbstractUrban flood modelling plays a key role in assessment of flood risk in urban areas by providing detailed information of the flooding process (e.g. location, depth and velocity of flooding). Accurate modelling results are the basis of reliable flood risk evaluation. In this paper, a new 3D unstructured mesh urban flooding model developed in [1] has been applied to a flood event in a densely urbanized area within the city of Glasgow. Good agreement has been achieved when comparing the results with those published in other 2D shallow water models [2,3] in ponded areas. However, larger vertical velocity (> 0.2 m/s) and larger differences between the 3D and 2D model can be observed in areas with greater topographic gradients (> 3%). Through the modelling of a real flooding event this paper helps illustrate the case that 3D modelling techniques are promising to improve accuracy and obtain more detailed information related to urban flooding dynamics. This helps to obtain better assessments of flood damage and vulnerability of urban areas. To the * Corresponding author Email address: f.fang@imperial.ac.uk (F. Fang)Preprint submitted to Elsevier January 18, 2015 best of our knowledge, this is the first paper to apply a 3D unstructured mesh finite-element model to a real urban flooding event. It highlights some of the differences between the 3D and 2D urban flood modelling results.

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Modelling of urban flooding due to Yangtze River dike break

Cited by 3 publications

References 33 publications

Multi-Mode Surface Generalization Supports a Detailed Urban Flooding Simulation Model

Multi-Mode Surface Generalization Supports a Detailed Urban Flooding Simulation Model

Editorial

Application of a Three-Dimensional Unstructured-Mesh Finite-Element Flooding Model and Comparison with Two-Dimensional Approaches

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