Substantial erosion of underwater topography in inundated area of large lakes using in situ bathymetry and multi-resource remote sensing on the Tibetan Plateau

Study region nine large lakes on the Tibetan Plateau. Study focus Lake represents a critical component of water resources on the Tibetan Plateau, little attention has been paid to the evolution of underwater topography in inundated area caused by lake expansion. In this study, we integrated models with in situ bathymetric data and Landsat images with multiple machine learning methods across nine lakes, analyzed the changes in underwater topography since 2000. New hydrological insights for the region Significant topographic changes were observed in all inundated areas since 2000, dominated by erosion with an average erosion depth of 3.34 m. Angdaer Co experienced the maximum average erosion depth (5 m), while Ayakekumu Lake exhibited the minimum (1.93 m). The total erosion volume across the nine lakes reached 2.61 × 10 9 m 3 , with Ayakekumu Lake and Aqikekule Lake both recording the largest erosion volumes (5.93 ×10 8 m 3 ), and Dulishi Lake the smallest (1.16 ×10 8 m 3 ). Due to the limitation of initial topography, only sediment volume of parts lakes was estimated with 7.65 × 10 8 m 3 and distributed in the deep area, and the largest sediment was Aykekumu (4.6 ×10 8 m 3 ) and Aqikekule (1.6 ×10 8 m 3 ). Erosion of underwater topography showed a strong positive correlation with runoff and precipitation. This study highlights significant change of underwater topography in inundated areas driven by lake expansion, offering new insights into the dynamics of lake evolution and sediment processes.