Nanda Madhusmita, Nair Archana M
Earth System Science and Engineering Division, Department of Civil Engineering, Indian Institute of Technology Guwahati, Guwahati, 781039, India.
Earth System Science and Engineering Division, Department of Civil Engineering, Indian Institute of Technology Guwahati, Guwahati, 781039, India.
J Environ Manage. 2025 May;381:125250. doi: 10.1016/j.jenvman.2025.125250. Epub 2025 Apr 4.
The Brahmaputra river system is one of Asia's largest and most dynamic transboundary rivers. Yet, limited studies are available on the water isotopes of this river. Therefore, this article aims to address this limitation by addressing the river's complex hydrological processes and its climatic influence using the stable isotope technique. A comprehensive dataset of water isotopes in precipitation, river water, and groundwater was generated for multiple locations within the basin from the year 2022-2024. Seasonal observations were also conducted along different parts of the Brahmaputra river system within the Indian territory. Seasonal isotopic variations in precipitation (δD: 93.33 ‰ to -67.28 ‰, δO: 13.37 ‰ to -9.59 ‰) show depleted signatures during the post-monsoon due to intense rainout. Enriched values of precipitation (δD: 97.01 ‰-40.91 ‰, δO: 13.12 ‰-4.09 ‰) during the pre-monsoon indicate significant evaporation. Spatial variation in river water (δD: 112.67 ‰ to -27.68 ‰, δO: 15.45 ‰ to -4.84 ‰) points to isotopic depletion in upstream regions, while downstream reaches display isotopic enrichment. The distinct isotopic signatures in different reaches of the river are due to variations in basin characteristics. The river water isotopic composition reflects the combined effect of hydrological processes such as evaporation and variability in the mixing of water from diverse sources such as glacial melt, snowfall, rainfall, and groundwater. These findings contribute to understand water sources, evaporation-precipitation dynamics, and regional hydrological processes. Consequently, this knowledge helps in taking appropriate measures for the crucial management of water resources in changing climate scenarios.
雅鲁藏布江河水系是亚洲最大且最具活力的跨界河流之一。然而，关于这条河流的水同位素的研究却很有限。因此，本文旨在通过运用稳定同位素技术来研究该河流复杂的水文过程及其气候影响，以解决这一局限性。针对2022年至2024年期间流域内多个地点，生成了一个关于降水、河水和地下水的水同位素综合数据集。同时，还在印度境内雅鲁藏布江河水系的不同河段进行了季节性观测。降水的季节性同位素变化（δD：93.33‰至 -67.28‰，δO：13.37‰至 -9.59‰）显示，由于强烈的降雨洗脱作用，季风后期的同位素特征出现贫化。季风前期降水的富集值（δD：97.01‰ - 40.91‰，δO：13.12‰ - 4.09‰）表明存在显著的蒸发作用。河水的空间变化（δD：112.67‰至 -27.68‰，δO：15.45‰至 -4.84‰）表明上游地区同位素贫化，而下游地区则显示同位素富集。河流不同河段明显的同位素特征是由于流域特征的差异所致。河水的同位素组成反映了诸如蒸发等水文过程以及来自冰川融水、降雪、降雨和地下水等不同水源混合变化的综合影响。这些发现有助于理解水源、蒸发 - 降水动态以及区域水文过程。因此，这些知识有助于在气候变化情景下采取适当措施对水资源进行关键管理。
