Author(s): Jie Li; Yi Zhang; Zhehan Zhou; Minghao Chu; Chenghao Zhu

Linked Author(s): Jie Li, Yi Zhang, MINGHAO CHU

Keywords: Channel incision; Braided reach; Lower Yellow River; Xiaolangdi Reservoir

Abstract: The Lower Yellow River (LYR) has underwent significant channel degradation after the operation of the Xiaolangdi (XLD) reservoir in 1999. It is estimated that the cumulative channel scour volume was 2.03×109m3 in the whole LYR, with the cumulative channel scour volume in the braided reach accounting for 70% during the period from 1999 to 2018. Severe channel scour has led to rapid channel incision in the braided reach of the LYR. In this study, variations in the cumulative channel incision depth at cross-sections and the stage-discharge relationships at hydrometric stations were investigated in this reach. The results show that the cumulative channel incision depths at cross-sections varied from 1.1 m to 4.2 m along the braided reach, and the reach-scale cumulative channel incision depth was up to 2.9 m. The water levels at the HYK station decreased significantly at the given discharges of 500 m3/s and 3000m3/s, with the values of 3.3 m and 2.1 m, respectively. The influence of the incoming flow and sediment regime on the channel incision was investigated in the braided reach, and an empirical equation was established between the cumulative channel incision depth and the previous 5-year average incoming sediment coefficient. The calculated data using the proposed equation agreed well with the observed data.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221758

Year: 2022