Author(s): Kyeongdong Kim; Dongsu Kim; Ikhan Lee

Linked Author(s): kyeongdong-kim@uiowa.edu

Keywords: Unsteady flow; Flood wave; Free-surface slope; Hysteresis; Diagnosis

Abstract: Hysteresis significantly affects the accuracy of hydrological measurements in rivers, especially during unsteady flow conditions caused by flood events. Traditional stage-discharge curves often fail to account for these dynamic complexities, resulting in substantial errors. This study presents a novel method named as Hysteresis Diagnostic Index (HDI) for diagnosing the degree of severity of stage-discharge hysteresis enabling to classify flood wave types during development of a flood event whereby using the free-surface slope. The proposed method denoted that a single flood event can be developed with the sequence of kinematic, diffusive, and dynamic waves depending on its hysteretic severity. The methodology was applied to in-situ data from the Naju gaging station on the Yeongsan River located in South Korea, a site characterized by low gradients where the prominent hysteresis during large flood events is present. The results, visualized through color-coded wave type classification, could demonstrate hysteresis severity and subsequent type of flood wave.

DOI: https://doi.org/10.64697/978-90-835589-7-4_41WC-P1575-cd

Year: 2025