Lake bathymetric reconstruction and water storage estimation method based on terrain feature similarity

Closed-basin lake hydrological elements serve as important indicators of climate change. However, because of natural constraints and limited monitoring conditions, the hydrological information (such as area, water level, and storage) of lakes on the Qinghai-Tibet Plateau remains insufficiently understood, which poses challenges in the quantitative assessment of lake water storage and its variations. In this study, a lake water storage estimation method that is based on surrounding topographic parameters is proposed. By calculating and extrapolating terrain parameters such as slope variations around the lake, a reasonably accurate digital representation of underwater topography can be obtained, enabling the quantitative evaluation of lake water storage. Nine lakes on the Qinghai-Tibet Plateau with available monitoring or research data are selected to verify the applicability and accuracy of the proposed method. The results reveal that the relative errors of the simulated maximum water depth range from 8 to 47%, with larger errors observed for Yamdrok Lake and Dongge Co'nag. The relative errors of the simulated average water depth range from 7.5 to 47%, with greater deviations observed for Xingxinghai and Kuhai Lake. For Ra'ang Co, Cuoe Lake, Anglaren Co, and Mapam Yumco, the relative error of comparison with the measured points is less than 20%. The model incorporates multiple functional forms and multidirectional profile combinations, rendering the results more consistent with actual geomorphological characteristics and robust to topographic noise. This study provides a useful reference for estimating water storage in lakes lacking measured data on the underwater topography.