Risk Assessment of Urban Floods Based on a SWMM-MIKE21-Coupled Model Using GF-2 Data

Jianzhu Li,Zhengxiong Cao,Ping Feng,Lidong Zhao,Jun Fu,Ting Zhang

doi:10.3390/rs13214381

Jianzhu Li, Zhengxiong Cao + Show 4 more

Open Access

https://doi.org/10.3390/rs13214381

Copy DOI

Abstract

Global climate change and rapid urbanization have caused increases in urban floods. Urban flood risk assessment is a vital method for preventing and controlling such disasters. This paper takes the central region of Cangzhou city in Hebei Province as an example. Detailed topographical information, such as the buildings and roads in the study area, was extracted from GF-2 data. By coupling the two models, the SWMM and MIKE21, the spatial distribution of the inundation region, and the water depth in the study area under different return periods, were simulated in detail. The results showed that, for the different return periods, the inundation region was generally consistent. However, there was a large increase in the mean inundation depth within a 10-to-30-year return period, and the increase in the maximum inundation depth and inundation area remained steady. The comprehensive runoff coefficient in all of the scenarios exceeded 0.8, indicating that the drainage system in the study area is insufficient and has a higher flood risk. The flood risk of the study area was evaluated based on the damage curve, which was obtained from field investigations. The results demonstrate that the loss per unit area was less than CNY 250/m2 in each return period in the majority of the damaged areas. Additionally, the total loss was mainly influenced by the damaged area, but, in commercial areas, the total loss was highly sensitive to the inundation depth.

Highlights

Published: 30 October 2021Global climate change [1,2] has led to dramatic changes in the processes and elements of the water cycle [3]
By coupling the SWMM and MIKE21 simulations, this study provides a more detailed understanding of the surface flows and inundation processes in the study area
The urban flood risk in the study area was estimated based on the damage curves obtained from field investigations, and the results show that 85% of the damaged areas had a loss per unit area of less than CNY 250/m2 under different return periods

Summary

Introduction

Global climate change [1,2] has led to dramatic changes in the processes and elements of the water cycle [3]. Together with urbanization [4] and land-use change, our living environment has changed dramatically [5,6,7]. Extreme precipitation events have been frequent in recent decades, and urban floods have become increasingly severe. In China, rainstorms and floods are relatively concentrated because of the country’s monsoon climate. With the rapid development of urbanization in recent decades, urban floods have become more severe, including the rainstorm in Jinan City [9] in 2007; the rainstorm in Beijing City [10]

Objectives

Methods

Results

Discussion

Conclusion