Abstract: This study aims to verify the low-carbon attributes of hydropower projects. Focusing on the Pubugou hydropower project commissioned in late 2010 on the mainstream of the middle Dadu River, we examine the spatiotemporal evolution and driving mechanisms of carbon storage in the reservoir rim region using the InVEST model and Geodetector, based on its 1990-2023 land use data. The results indicate the region’s land use underwent three distinct stages in the study period－natural succession, engineering disturbance, and ecological adjustment. Forest land consistently remained dominant in land cover type, with its proportion gradually increasing up to 70.2%. Spatially, carbon storage featured a pattern of being enriched at higher elevations and sparse at lower elevations; Temporally, it grew at an average annual rate of 0.11%, verifying carbon sequestration has been enhanced in the region since the completion of this project. Forest land acted as the core contributor to carbon sequestration. We also find that natural factors were dominant in the spatial differentiation, while socioeconomic factors imposed relatively weak influences. The interaction of dual factors further enhanced this spatial differentiation. These findings provide a novel perspective for assessing the low-carbon benefits of hydropower projects in alpine valley regions, and lay a basis for ecological management of reservoir rims.

Key words: environmental science, hydropower project, carbon storage, land use change, InVEST model, geodetector