Li et al. (2025) Deciphering Intra‐Annual Isotope Fluctuations of River Water in an Arid‐Alpine Watershed: Source Discrimination and Evaporation Quantification

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Identification

• Journal: Hydrological Processes
• Year: 2025
• Date: 2025-12-01
• Authors: Ziyi Li, Wenbo Rao, Hongbing Tan, Xiaohui Li, Xi‐Ying Zhang
• DOI: 10.1002/hyp.70357

Research Groups

Not specified in the abstract.

Short Summary

This study investigated the intra-annual variations of Golmud River water isotopes in 2019 to identify recharge sources and quantify evaporation impacts, revealing that glacial meltwater and groundwater are primary recharge sources and that watershed-scale evaporation loss averages approximately 9%.

Objective

• To investigate the intra-annual variations of Golmud River water isotopes during 2019 to identify recharge sources and quantify evaporation impacts, providing scientific guidance for local water resources management.

Study Configuration

• Spatial Scale: Golmud River basin, including upper reaches (Xiaonanchuan, Yeniugou), middle reaches (below Nachitai), and downstream (near Kunlun Lake, east branch).
• Temporal Scale: Annual (2019) with intra-annual (monthly) resolution.

Methodology and Data

• Models used: MixSIAR modelling, Rayleigh fractionation model.
• Data sources: In-situ measurements of water isotopes (δ²H and δ¹⁸O).

Main Results

• River water exhibited higher δ²H and δ¹⁸O values in July compared with other months.
• Spatially, δ²H and δ¹⁸O values were lowest in Xiaonanchuan (δ²H: −71.59‰ to −56.62‰; δ¹⁸O: −11.84‰ to −9.46‰) and highest in Yeniugou (δ²H: −66.2‰ to −46.79‰; δ¹⁸O: −10.98‰ to −6.52‰).
• River water isotopes plotted below the local meteoric water line, and lc-excess decreased from upper to lower reaches, indicating intensified evaporation along the flow path.
• The mean recharge elevation of river water exceeded 4700 m.
• Glacial meltwater (29%–57.5%) and groundwater (28.6%–46.8%) constituted primary recharge sources to river water, with enhanced precipitation contribution (24.2%) in July.
• Watershed-scale evaporation loss averaged approximately 9%, remaining negligible in Xiaonanchuan while attenuating along the water flow in Yeniugou, with the highest value reaching 22% near Kunlun Lake and 25.8% in the downstream (east branch).
• The evaporation loss stability of the middle reach suggested the possibility of glacial meltwater recharge to river water through faults.

Contributions

• Advanced the understanding of water cycling in arid-alpine watersheds.
• Provided critical insights for optimizing regional water allocation.
• Highlighted the combined use of the Rayleigh fractionation model and lc-excess as a potential approach for river evaporation assessment.

Funding

Not specified in the abstract.

Citation

@article{Li2025Deciphering,
  author = {Li, Ziyi and Rao, Wenbo and Tan, Hongbing and Li, Xiaohui and Zhang, Xi‐Ying},
  title = {Deciphering Intra‐Annual Isotope Fluctuations of River Water in an Arid‐Alpine Watershed: Source Discrimination and Evaporation Quantification},
  journal = {Hydrological Processes},
  year = {2025},
  doi = {10.1002/hyp.70357},
  url = {https://doi.org/10.1002/hyp.70357}
}