Possibility of landslide damming in the Vakhsh River catchment and its effect on the hydraulic schemes and population

Abstract

Large-scale landslides in mountainous regions can create high natural dams resulting in valleys inundation and subsequent disastrous outburst floods that can devastate entire valleys and cause serious problems for the hydraulic schemes located far downstream. Thus, it is very important to identify sites where such damming could occur in the catchment areas of rivers, where artificial dams and reservoirs are constructed. A case study from the Vakhsh River catchment is presented where evidence of an extremely large slope instability have been identified. Its safety factor was determined considering the possibility of an earthquake occurrence in this tectonically active region. The height of the anticipated natural dam and volume of the dammed lake were estimated as well based on the empirical relationships. Measures aimed to mitigate the potential risks are proposed.