Abstract
Landslide dams, created when rapid mass movements block river channels, are strongly influenced by hydrological conditions of the upstream catchment. The formation and long-term stability of landslide dams are closely linked to hydrological factors such as streamflow, lake area, water level and precipitation. Conversely, the formation of these dams changes upstream and downstream hydrological regimes such as water storage, sediment transport and flooding risk. Since the previous reviews by Costa and Schuster, (1988) and Korup, (2002), several review articles have focused on the formation and failure mechanism of landslide dams (e.g., Fan et al. 2020; Zheng et al. 2021). These reviews have mainly focused on geomorphological factors of dams and their formation. However, the hydrological processes around and within the landslide dam are crucial for the behavior of landslide dams, the downstream hydrology and potential flash flood risks. Therefore, there is an urgent need to study hydrological processes upstream and within landslide dams in order to better predict landslide dam stability, up- and downstream consequences. Streamflow (inflow and outflow), precipitation and snowmelt, water level, dammed lake area, lake volume, water balance, surface runoff, erosion, sedimentation, and water storage capacity are key factors for assessing the behavior of landslide dams. This review analyzes the current state of knowledge on hydrological processes influencing the evolution, and failure of landslide dams. It further examines the role of remote sensing and modelling techniques in assessing hydrological factors where field data are scarce.