Author(s): Mingfu Guan; Kaihua Guo

Linked Author(s): Kaihua Guo

Keywords: Emergency response; Flash flooding; Mountainous ungauged areas; Numerical simulation

Abstract: Flash flooding is particularly devastating due to its nature of sudden onset, high flow velocities and short duration. Identifying early signals for a flash flood, particularly in ungauged mountainous regions, is crucial to mitigate their impacts. To address this, our study proposes an approach based on a flash flood hazard index, utilizing gridded flood hydrodynamic modeling. To demonstrate the effectiveness of our methodology, we applied it to the 2022 Datong flash flooding event. This flash flood was triggered by a heavy rainfall event with an intensity exceeding 34 mm/h, resulting in 25 fatalities and 6 missing individuals (data as of August 21,2022). Initially, we conducted two-dimensional hydrodynamic modeling of the flash flooding induced by the rainfall across the entire Datong basin. The modeled inundation was then compared to observed flood extents, revealing a general agreement. However, it should be noted that uncertainties exist due to limited data availability in ungauged mountainous areas. Subsequently, the modeled flood hydrodynamics were utilized to derive a Flash Flood Vulnerability Index (FFVI), which can serve as an early warning signal for emergency response purposes. The study offers a valuable and reliable approach for predicting and mitigating flash floods.

DOI: https://doi.org/10.3850/iahr-hic2483430201-483

Year: 2024