Global Groundwater Stable Water Isotope Dataset

Description

Groundwater stores approximately 96% of the Earth’s liquid freshwater and is critical for sustaining ecosystems, agriculture, and human water security. Stable isotopes of hydrogen and oxygen (δ²H and δ¹⁸O) are essential tracers for understanding groundwater recharge, circulation, and climate interactions. However, global-scale analyses are hindered by data fragmentation across regional studies and diverse repositories. Here we present a global synthesis of groundwater stable water isotopes comprising 72,307 records, including 13,467 literature-derived records from 320 peer-reviewed studies and 761 primary field measurements from an arid basin and 58079 for website data. The dataset spans 1961–2024. To facilitate macroscopic analysis, records were operationally categorized into four depth classes: very shallow (0–10 m), shallow (10–50 m), intermediate (50–200 m), and deep (>200 m). Each record includes metadata on provenance, extraction method, instrument type, reported uncertainty, and quality-control level. For records from major international databases (USGS NWIS, IAEA WISER, wiDB), we do not redistribute the data but instead provide query instructions and links to the original repositories. Preliminary analyses reveal pronounced spatial heterogeneity and vertical stratification: shallow groundwater largely reflects modern meteoric recharge with variable evaporative enrichment, whereas deep groundwater exhibits lighter isotopic compositions. This quality-controlled and harmonized dataset provides a robust empirical foundation for regional to global studies of hydrological cycles, groundwater sustainability, and Earth system modeling.

Institutions

• Northwest Normal University

  Gansu, Lanzhou

Categories

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