Author(s): Emma House; Ehab Meselhe; Marian Muste; Ibrahim Demir
Linked Author(s): Marian Muste, Ehab Meselhe, Ibrahim Demir
Keywords: Streamflow hysteresis Momentum forces River monitoring Forecasting
Abstract: Hysteresis, characterized by non-unique relationships and phase shifts in flow variables, is common in the unsteady flow of lowland rivers, especially during large flood waves. This phenomenon can lead to significant errors in streamflow estimates when monitoring relies on unique rating curves like the stage-discharge relationship. Using a combined 1D/2D hydraulic model, this study examines the St. Venant momentum terms to identify hysteresis indicators across various storm events along the Illinois River, USA. Results show that non-hysteretic flow aligns with balanced gravity and friction forces, typical of kinematic wave conditions, while hysteretic flow arises from imbalances among these forces, with convective and diffusive terms playing a crucial role. In hysteretic cases, pressure gradients are comparable to kinematic terms, and convective acceleration remains active, with non-unique relationships and temporal lags emerging in the momentum terms. These findings highlight key drivers of streamflow hysteresis, offering insights to refine streamflow monitoring and forecasting.
Year: 2025