Slope Stability Monitoring of Hydroelectric Dam and Upstream Watershed Areas Utilizing Satellite Interferometric Synthetic Aperture Radar (InSAR)

Abstract

Dams offer significant benefits such as power generation, flood control, irrigation, and tourism. However, when mismanaged, they pose a high risk of catastrophic failure, potentially releasing large volumes of water rapidly, resulting in severe downstream damage, environmental impacts, injuries, and loss of lives. Effective dam monitoring is essential to evaluate slope stability, detect slope behaviour changes, and deliver early warning for potential hazards. Upon detecting any deformations in the dam or its watershed areas, prompt interventions can be initiated. Interferometric Synthetic Aperture Radar (InSAR) is the measurement technique of signal phase change between two images at the same location and at different times, it will be a proficient method for monitoring ground or slope changes across vast areas without the installation of on-site instrumentation. The dataset used in this work consists of 392 images of Sentinel-1 from 1 September 2018 to 11 August 2023 to conduct long-term InSAR data analysis. Monitoring the dam and its watershed is crucial, given that over 30% of U.S. dam failures result from overtopping. Slope failure events at the upstream area can cause abrupt water level rises, further increasing the risk of overtopping and major instability. This study explores slope deformation around dams and their watersheds using satellite long-term InSAR technology using a study case from one of the dams in Indonesia. The outcomes will provide insights into dam safety and shed light on the strengths and constraints of the InSAR technology.