Calculation and analysis of reservoir capacity based on oblique photogrammetry

To meet the requirements for re-verification of the reservoir capacity curve in the context of reservoir safety monitoring facility construction, this study proposes an integrated approach combining unmanned aerial vehicle (UAV) oblique photogrammetry with LiDAR and unmanned survey boats to acquire high-resolution elevation data for both above-water and underwater terrain. Digital elevation models (DEMs) of the reservoir were independently generated using airborne LiDAR point clouds and dense point clouds derived from aerial triangulation of oblique photogrammetry data. Reservoir storage capacity calculated using the DEM-based grid method. The consistency and accuracy of the results assessed through cross-validation between the two datasets. Results indicate that the DEM constructed from matched dense point clouds in aerial triangulation yields reliable reservoir capacity estimates, meeting the precision requirements for routine monitoring by reservoir management authorities. Furthermore, by comparing the calculated capacity with the currently operational capacity of the reservoir, this study identifies and analyzes the underlying factors contributing to capacity changes, thereby determining an updated and accurate reservoir capacity. This methodology provides a cost-effective and efficient solution for periodic reservoir capacity monitoring, particularly suitable for management agencies operating under constraints in terms of hardware, software, and technical resources.