Abstract

With the frequent occurrence of extreme rainfall and the change of urban surface caused by human activities, urban waterlogging has gradually become a common disaster in many cities. In this paper, in order to deal with the urban waterlogging disasters, three-dimensional (3D) simulation of regional urban waterlogging was established based on high-precision digital elevation model (DEM). The project takes Zhongnan University of Economics and Law as the research area to setup the simulation. Firstly, the sub-catchment areas are divided by the watershed extraction method. Secondly, the research area is gridded to calculate the scope and volume of waterlogging area. Finally, combined with the rainstorm intensity formula, the statistics of local area underlying surface, and Soil Conservation Service (SCS) model, the urban waterlogging disaster model is established. Then, the waterlogging disaster calculation under different return period rainfall situations is realized and based on 3D technology, the 3D scene of research area and 3D simulation of waterlogging are shown by using CityEngine and Cesium. The data verification of the model is based on the rainfall data, and the urban waterlogging disaster results in Wuhan in 2016. The simulation results are basically consistent with the waterlogging disaster in 2016. And the research shows that the sub-catchment area divided by the watershed extraction method can take into account the blocking effect of terrain on surface runoff, and the results are consistent with the actual terrain. Waterlogging simulation in a small area can accurately locate the affected areas and buildings, and 3D visualization technology can be used as an effective means of transmitting disaster information to provide basis for emergency decision-making. Only the geographical data of the local area and the rainfall data are needed for the method for simulation calculation, which makes it easily to transplant to other areas and can provide an important idea and method for the flood prevention and control in flood season for reservoir, tailings pond, factories and so on.

Highlights

  • With the increase of the cities’ area and the appearance of big cities, the landform of cities has been changed

  • The change of urban geomorphology has broken the balance of rainfall and evaporation and the frequency of extreme weather caused by global climate change has increased in recent years

  • Many urban waterlogging cases show that urban waterlogging disasters with regional characteristics, which happens at city small low-lying area

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Summary

Introduction

With the increase of the cities’ area and the appearance of big cities, the landform of cities has been changed. The change of urban geomorphology has broken the balance of rainfall and evaporation and the frequency of extreme weather caused by global climate change has increased in recent years. Due to these two reasons, urban waterlogging has become a common disease in many southern cities in the rainy season. In the study of waterlogging, DEM model is the foundation of dividing catchment area and simulate the runoff. This paper further expands the research ideas and methods of urban waterlogging disaster, and provides reference for the simulation and early warning of waterlogging in small areas

Research ideas and methods
Overview of the model area
The watershed extraction method
High precision terrain model
Automatic watershed extraction method
The rainstorm intensity formula
The SCS model
The process of confluence disaster
The calculation of submergence depth
Elevation data
Rainfall information
Drainage information
Submergence depth calculation
Spatial data preparation
Waterlogging disaster simulation
Findings
Conclusions
Full Text
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