Surges generated by water export from an impounded channel

This study combines physical experiments and Smoothed Particle Hydrodynamics (SPH) simulations to quantify hydrodynamic characteristics of negative and undular surges in an impounded channel. For negative surges in shallow-water conditions, unidirectional wave attenuation demonstrates quantitative agreement with the Ippen-Kulin model predictions. Systematic analysis reveals a cubic decay factor-relative wave height relationship when wave steepness exceeded 0.004, expanding previous formulations through inclusion of wave steepness effects. Damping dynamics exhibited negligible dependence on still water depth during oscillatory cycles. For undular surges, empirical correlations quantified propagating wave parameter variability, while vertical velocity profiles displayed linear stratification across the water column, validating Boussinesq's hypothesis . A depth-independent initiation threshold (1.12 ≤ d 1s / d n ≤ 1.24) was identified, where d 1s = water depth at the first hydraulic jump and d n = surge toe depth, decoupled from boundary-layer development at the surge front. These findings contributes to a better understanding of these complex hydrodynamic phenomena. • Negative surge decay is influenced by both wave amplitude and steepness, emphasizing the role of steepness in predictions. • Damping of negative surges remains constant across varying water depths, simplifying modeling in impounded channels. • Empirical formulas capture wave parameter changes in undular surges, aiding prediction against varied flows. • Vertical velocity beneath surges confirms Boussinesq's assumption. • Onset of undular surges is independent of water depth and boundary-layer development.