The Trend in the Risk of Flash Flood Hazards with Regional Development in the Guanshan River Basin, China

Yanjun Zhang,Jinjin Wu,Ningyue Chen,Xin Xu,Wenxun Dong,Yixuan Zou

doi:10.3390/w12061815

Abstract

The economic development of China’s mountainous areas has been rapid, but the impact of flash floods is often ignored during regional development planning. Therefore, a method needed to be developed to simulate flash flood disasters and analyze the trends in flash flood disasters with regional development. Taking Guanshan River Basin as the research area, we combined the digital elevation model (DEM) with the inflow hydrograph, using the topography-based hydrological model (TOPMODEL). Verified by historical flash flood disasters, the watershed model was built based on the finite volume conservation flood routing model (FLO-2D). Then, we simulated the hazard distribution of flash flood disasters, developed a risk status assessment factor (RSAF) for flash flood disasters and calculated the increased ratio from 2003 to 2018. The results show that in 2003, the total hazard area of flash flood disasters affecting human settlements was 61,121 m2, which increased to 118,404 m2 in 2018. Since 2003, with the development of the regional economy, more residents moved to risk and extreme risk zones; thus, the risk of flash flood disasters also increased. Due to the significant damage caused by the flash flood on 5 August 2012, some of the local residents moved away from the high risk and extreme risk zones, indicating that the risk trend of flash flood hazard was consistent with the regional development of Guanshan River. We provide suggestions for regional economic development planning; the risk assessment for flash flood disasters must be considered to ensure the stable development of the regional economy, and using the RSAF would be efficient.

Highlights

Flash floods have serious social and economic impacts and destroy people’s lives, houses, and social networks [1]
To further evaluate the risk status of flash flood disasters and determine the relationship between flash flood disasters and regional development in the Guanshan River Basin, we developed the risk status assessment factor (RSAF) for flash flood disasters and compared the risk status of flash flood disasters in 2003, 2013, and 2018, by calculating the increased ratios, providing suggestions for regional economic development planning
We selected the Guanshan River Basin as the research area, simulated the inflow hydrograph using TOPMODEL, and built a watershed model based on FLO-2D to simulate the No 20120806 flood

Summary

Introduction

Flash floods have serious social and economic impacts and destroy people’s lives, houses, and social networks [1]. Floodable areas are near rivers, which are often water resources for domestic, agricultural, and industrial purposes, such as the Nile River Basin [2]. Humans often live in floodable areas due to the better living condition. Once flood disasters occur, huge losses ensue. In late September 2000, a devastating flood struck Gangetic West. India, having severe impacts on rural settlements [3]. In September 2002, a storm triggered a series of flash floods on the Gard River in the south of France [4]

Methods

Results

Discussion

Conclusion