1 Introduction Fluvial flood is among the most devastating natural disasters, resulting in substantial economic losses and fatalities worldwide each year (Douris & Kim, 2021). The intensity and frequency of fluvial flood events continue to rise with the increasing occurrence of extreme precipitation, which further exacerbates threats to water security (Kumar et al., 2023). To effectively prevent and mitigate flood risks, timely and accurate monitoring of flood processes is essential.