Remote sensing for mountainous river monitoring: application progress and prospects

Mountainous rivers, critical components of the global water cycle and ecosystems, pose significant challenges to water resource management and flood disaster mitigation due to their complex hydrological processes and fragile geological environments. This review thoroughly analyzes how remote sensing technology, leveraging its macro-scale, rapid, non-contact, and multi-scale observation capabilities, effectively overcomes the inherent limitations of traditional monitoring in complex mountainous terrains and harsh environments. We find that significant advancements have been made in remote sensing for mountainous river monitoring, encompassing water level, discharge, channel morphology, water quality, and snow-ice cover. Notably, the introduction of high-precision altimetry satellites (e.g., SWOT) and artificial intelligence algorithms has substantially enhanced monitoring capabilities. However, key bottlenecks persist, including the fusion of multi-source heterogeneous data, high-precision inversion of hydrological parameters in complex terrain, and the deep integration of remote sensing outcomes with water conservancy operations. Accordingly, this paper identifies critical theoretical and technical issues requiring future research, aiming to provide scientific guidance for advancing intelligent and operational applications of remote sensing in mountainous river monitoring.