GIS-based remote sensing analysis of the spatial-temporal evolution of landslides in a hydropower reservoir in southwest China

The evolution of reservoir landslides upstream of river buildings is a key issue because landslides continue to cause damage to the ecological environment, especially the safety of dams and the operation of reservoirs. Based on geographic information system (GIS), four high-resolution remote sensing images captured at a hydropower reservoir in southwest China during four different periods are used to interpret landslides. Landslide maps coupled with lithological setting, water level change history and some other factors are used to illustrate the spatial-temporal evolution of landslides in the upstream reservoir of river buildings. The results from this analysis indicate that the landslides are more likely to occur in Quaternary deposits, fractured rock masses and water softened rock masses, whose engineering properties are quite sensitive to water. Three main types of landslides are observed in the reservoir, include gully landslide, bank collapse and deep-seated landslide, among which bank collapse is the dominate type. Fluctuation of water level, together with the human activities and lithological setting, affect the deformation and failure process of the landslides. The deep-seated landslides in the reservoir were observed to experience a relative long period of large deformation until the occurrence of a disaster.