Identification of potential geological hazards on dam-adjacent reservoir banks of hybrid pumped-storage power stations by integrating optical imagery and SBAS-InSAR

【Objective】Hybrid pumped storage projects are typically constructed adjacent to existing reservoirs or hydropower stations, characterized by large water level fluctuations and frequent regulation during operation. This leads to significant changes in boundary conditions along the dam-proximal reservoir banks, making bank stability a prominent geotechnical issue for safe project operation. Influenced jointly by frequent water level fluctuations, rainfall infiltration, road excavation, and proximity to water at the toe of slopes, the development of hazards such as landslides, deformation zones, and unstable accumulations along the reservoir banks is complex. Single remote sensing methods struggle to simultaneously capture topographic boundaries, engineering disturbances, and slow deformation information. In response, this study focuses on the dam-proximal reservoir banks of the Lianghekou hybrid pumped storage power station.【Methods】By integrating multi-source optical imagery with SBAS-InSAR technology, and considering the operational characteristics of water level regulation and engineering disturbances near the dam, we conduct identification of geological hazard risks and analysis of typical hazardous zones.【Results】Results show that overall deformation in the study area is minor, with most regions exhibiting Line-of-Sight (LOS) cumulative deformation between -25 mm and 40 mm, indicating general stability or weak deformation. Abnormal deformations mainly concentrate on both sides of the valley, mid-to-low slopes, near roads, and at water-adjacent fronts. Among the identified hazardous zones, the XZ-2 deformation zone shows the highest activity, with a cumulative deformation of -87 mm, primarily concentrated from the central to the front areas. Deformation in the XZ-1, Tuodaxi deformation zone, and XZ-3 landslide mainly occurs along the central roadway, lower to middle parts of the slope, and at the water-adjacent front. The unstable accumulation body opposite Wazhi Village exhibits progressive expansion from the front edge toward the middle and rear sections.【Conclusion】The findings indicate that optical imagery effectively identifies topographic boundaries and signs of engineering disturbance along the dam-proximal reservoir banks, while SBAS-InSAR supplements data on slow deformation. The integration of these two techniques provides valuable support for rapid screening and targeted re-evaluation of potential hazards near the reservoir banks of hybrid pumped storage projects.