Numerical Investigation of a Flash Flood Process that Occurred in Zhongdu River, Sichuan, China

Abstract

In 2018, a flash flood occurred in the Zhongdu river, which lies in Yibin, Sichuan province of China. The flood caused many casualties and significant damage to people living nearby. Due to the difficulty in predicting where and when flash floods will happen, it is nearly impossible to set up monitors in advance to detect the floods in detail. Field investigations are usually carried out to study the flood propagation and disaster-causing mechanism after the flood’s happening. The field studies take the relic left by the flash flood to deduce the peak level, peak discharge, bed erosion, etc. and further revel the mechanism between water and sediment transport during the flash flood This kind of relic-based study will generate bigger errors in regions with great bed deformation. In this study, we come up with numerical simulations to investigate the flash flood that happened in the Zhongdu river. The simulations are based on two-dimensional shallow water models coupled with sediment transport and bed deformation models. Based on the real water level and discharge profile measured by a hydrometric station nearby, the numerical simulation reproduced the flash flood in the valley. The results show the flood coverage, water level variation, and velocity distribution during the flood. The simulation offers great help in studying the damage-causing process. Furthermore, simulations without considering sediment transport are also carried out to study the impact of bed erosion and sedimentation. The study proved that, without considering bed deformation, the flood may be greatly underestimated, and the sediment lying in the valley has great impact on flood power.

Impact-Based Critical Areal Rainfall for Early Flood Warning: A Case Study of Zhulong River Watershed in the Upper Reaches of the Xiong’an New Area

“…However, there are still a few aspects that need to be enhanced in future studies to further promote the timeliness and accuracy of the early flood warnings [39,40]. For instance, the incorporation of remotely sensed precipitation products and gauges to measure precipitation in finer spatial and temporal dimensions [41,42], coupled with the simulation of distributed hydrological models and the main process of hydrological statistical yearbooks to attempt to generate hourly or sub-daily discharge data [43][44][45]. On this basis, it is possible to further investigate the use of the methods based on the rising rate in flood events and real-time accumulated precipitation to determine flood warning indicators to improve the foreseeability and accuracy of flood warnings.…”

Inundation Mapping and Flood Frequency Analysis using HEC-RAS Hydraulic Model and EasyFit Software

“…The focus of this research is to prepare a flood inundation map and models using HEC-RAS and EasyFit software to conduct a flood frequency analysis (Ardıçlıoğlu and Kuriqi 2019). Numerous studies (Brunner 2016;Hou et al 2018;Hou et al 2021;Karamma and Pallu 2018;Praveen et al 2020;Romali 2018;Son and Jeong 2019;Wijayanti et al 2017;Yang et al 2021) use various modeling approaches to minimize flood hazards. Among those modeling approaches, HEC-RAS and the analytical hierarchy process have been considered for this study, since they focus on detailed terrain analysis in river simulation using multiple criteria when evaluating alternative approaches (Ardıçlıoğlu and Kuriqi 2019;Romali 2018;Praveen et al 2020;Vijayan et al 2021).…”

Numerical Simulation of Flood Propagation in the Kelara River Flood Early Warning System

“…The main component of a flood early warning system is numerical modeling, which is used for flood prediction (Yang et al 2021;Vijayan et al 2021;Praveen et al 2020;Son and Jeong 2019;Krzhizhanovskaya et al 2011). Numerical modeling is the answer to the limitations of the physical model, the limitations of direct observation, and the limitations of field measurement data.…”