Development Trend of Downstream Scouring in Flood Discharge Section of Three Gorges Dam

The Three Gorges Dam faces a large outflow, numerous flood discharge facilities, and difficult scheduling and operation during the flood season. The downstream scouring situation of the flood discharge section is complex at different time. Based on the scheduling and operation of flood discharge facilities in different periods since the operation of the project's water storage, the downstream terrain scouring of the flood discharge section in typical years was analyzed. The measured downstream area scouring, as well as the scouring point of the right side of the left guide wall and the left side of the lower longitudinal section of the anti-scouring wall, morphology, and scouring pit elevation in different periods were compared. The development and change trends of downstream scouring of the flood discharge section were studied. The research results indicate that the overall morphology of the downstream scouring pit of the flood discharge section is basically the same in different periods. In the normal operation period, the lowest elevation of the downstream middle scouring pit of the flood discharge section is about 4 m higher than that of the cofferdam in the power generation period, and the scouring situation has generally improved compared with the previous period.