Surface Water Isotope Data of Xiyang River

This dataset contains the stable hydrogen and oxygen isotope compositions (δ²H and δ¹⁸O) of nine surface water sampling sites (P1 to P9) in the Xiying River, from upstream to downstream. The elevation of these sampling sites gradually decreases from 3,301 masl to 1,970 masl, revealing an isotopic gradient along the watercourse. The data spans from 2022 to 2025 and includes multiple sampling events across different seasons. High-frequency continuous observations are also recorded at some sites. This dataset provides fundamental data for investigating the recharge sources, evaporation effects, and water transport processes within the Xiying River basin.