Abstract:

Based on measured water level and discharge data in 2018, this paper investigates the propagation of flood waves in the river reach between Three Gorges Dam and Gezhouba Dam driven by hydropeaking regulation by using a one-dimensional analytical model. During daily hydropeaking operations at both dams, the outflow exhibited significant diurnal and semi-diurnal fluctuations, ranging from 1 500 to 2 000 m³/s for Three Gorges Dam and 1 200 to 1 500 m³/s for Gezhouba Dam in average. Similarly, the water level at Huanglingmiao and Nanjinguan stations fluctuated by about 0.5-0.8 m daily. The one-dimensional analytical model accurately simulates the fluctuation of water level and discharge between the two dams. The simulation results indicate that flood waves in the river reach propagate as high-frequency standing waves with a period of 1.2 hours. The maximum amplitudes of the standing waves are approximately 2.1 cm for water level and 210 m³/s for flow discharge. The flood waves are superimposed by the hydropeaking operations of both dams, and the timing of regulation at Gezhouba Dam significantly affects flood wave propagation. Specifically, increasing the regulation time from 0.6 to 1.2 hours substantially enhances the flood wave amplitude. While bottom friction of river channel has a negligible impact on wave height, it accelerates the attenuation of flood waves during propagation.

Key words: hydropeaking regulation, flood wave, analytical model, standing wave, energy attenuation