Author(s): Jianqing Zhang; Peng Li; Zhaofeng Li; Jing Zeng; Jiangping Chen; Jun Yan

Linked Author(s):

Keywords: Deepwater channel siltation detection; Multibeam bathymetry; Seismic reflection method in water; High-density resistivity method in water

Abstract: The average annual sediment accumulation in China's Three Gorges reservoir area exceeds 100 million tonnes, bringing challenges to reservoir capacity, ecological protection and waterway operation, while also presenting opportunities for sediment resource utilization. However, since the Three Gorges reservoir has been impounded, the water level in front of the dam has been raised by over 100m and the water level in the reservoir area has also risen significantly, which will greatly increase the difficulty of detecting river siltation, especially in distinguishing the silt layer from the sand layer. In this paper, based on a introduction of the working principles and observation methods of multibeam bathymetry, seismic reflection method in water and high-density resistivity method under water, the comprehensive geophysical detection method of the above three methods is applied to a deep-water river siltation detection in the Three Gorges reservoir area. The application results show that the multibeam bathymetry method can obtain the underwater topographic information, the seismic reflection method can survey the thickness of silt and sand layer, the high-density resistivity method can conduct a detailed survey of the key target strata in the survey area, and then combine with the core results of a few boreholes to calibrate the detected parameters of the target strata, and finally accurately obtain the spatial and temporal distribution characteristics of river siltation, providing accurate data support for managers to scientifically utilize the siltation sand resources.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0889-cd

Year: 2023