Landslide Detection and Deformation Control Analysis in the Reservoir Area of Wudongde Hydropower Station by InSAR Observations

After the construction of hydropower station, reservoir impoundment can directly affect the movement status of landslides within the reservoir area. Detecting landslides and revealing the relationship between landslide deformation and driving forces is crucial for reducing the threat of landslide hazards to residents and hydropower station in reservoir areas. In this study, active landslides in the reservoir areas of Wudongde Hydropower Station, were detected combining Interferometric Synthetic Aperture Radar observations and optical image interpretation. Through detailed verification and screening, we identified 128 landslides, most of which are located at an altitude of 1,000–2,000 m, with slopes of 20–35°. After reservoir impoundment, wading landslides were found to be more prone to change state than non-wading landslides. As the primary control factor of wading landslides, reservoir impoundment can either accelerate or decelerate landslide deformation depending on the equilibrium state between soil saturation and hydrostatic pressure. Furthermore, wavelet transform analysis indicates that rainfall and reservoir level significantly contribute to the seasonal oscillations of landslide deformation. The results of this study can contribute to the prevention of landslide hazards in the Wudongde reservoir area and other areas of the world where large hydropower stations have been constructed.