Rajan Shijin, Nandimandalam Janardhana Raju
School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
Environ Res. 2025 Jul 15;277:121587. doi: 10.1016/j.envres.2025.121587. Epub 2025 Apr 11.
The interaction between surface and groundwater is vital for sustaining the hydrological system and ecosystem balance. This study investigates river water-groundwater connectivity and recharge sources in the upper Yamuna River basin (UYRB) by integrating stable isotopes (δO and δH), hydrogeochemistry, and statistical analyses. Spanning the Himalayas and alluvial plains, the UYRB presents diverse topography, climatic conditions and human interferences, making it ideal for exploring spatial and seasonal effects on water resources. A total of 233 samples, including river water (n = 60), groundwater (n = 106), spring water (n = 18), rainwater (n = 35), and fresh snow (n = 14) were collected during 2022 to draw the results. Hydrochemical parameters exhibit a significant (p < 0.05) spatiotemporal influence, with glacial and snowmelt driving summer recharge in the upper catchment (UC), whereas ISM-driven precipitation dominates downstream recharge. River water isotopic composition is strongly influenced by altitude (summer: ILR = -0.36 ‰ per 100 m for δO, R = 0.4, p = 0.0004; winter: ILR = -0.17 ‰, R = 0.5, p < 0.0001), though this effect is less pronounced in rainfall, groundwater and spring water. Distinct ion chemistry characterises the UYRB with Ca.Mg-HCO water types prevail in the upper and mid-catchments, while mixed or saline types dominant in the lower catchment. Groundwater and river water isotopes closely align with the derived LMWL (δH = 7.63 × δO + 7.83; R = 0.99), indicating the signatures of regional precipitation in their recharge. Elevated d-excess values in UC rainfall (x‾ = 12.3 ‰) and snow (x‾ = 18.1 ‰) suggest a combined influence of ISM and WD on regional moisture distribution. The multivariate analyses (PCA and HCA) confirm strong river water and groundwater interactions, particularly in the lower catchment. This study highlights catchment-specific RW-GW interactions and recharge sources in the water-scarce UYRB, providing critical insights for regional climate-resilient water resource management.
地表水与地下水之间的相互作用对于维持水文系统和生态系统平衡至关重要。本研究通过整合稳定同位素（δO和δH）、水文地球化学和统计分析，调查了亚穆纳河上游流域（UYRB）的河水与地下水连通性及补给来源。UYRB跨越喜马拉雅山脉和冲积平原，呈现出多样的地形、气候条件和人类干扰，使其成为探索对水资源的空间和季节影响的理想之地。在2022年期间共采集了233个样本，包括河水（n = 60）、地下水（n = 106）、泉水（n = 18）、雨水（n = 35）和新雪（n = 14）以得出结果。水化学参数呈现出显著的（p < 0.05）时空影响，冰川和融雪驱动上游集水区（UC）的夏季补给，而季风影响下的降水主导下游补给。河水同位素组成受海拔强烈影响（夏季：δO每100米的海拔梯度变化率ILR = -0.36‰，R = 0.4，p = 0.0004；冬季：ILR = -0.17‰，R = 0.5，p < 0.0001），尽管这种影响在降雨、地下水和泉水中不太明显。独特的离子化学特征表征了UYRB，Ca.Mg - HCO水型在上游和中游集水区占主导，而混合或咸水型在下游集水区占主导。地下水和河水同位素与推导的当地大气水线（LMWL）（δH = 7.63 × δO + 7.83；R = 0.99）紧密吻合，表明其补给中有区域降水的特征。UC降雨（x‾ = 12.3‰）和降雪（x‾ = 18.1‰）中升高的氘过量值表明季风和西风带对区域水分分布的综合影响。多变量分析（PCA和HCA）证实了河水与地下水之间强烈的相互作用，特别是在下游集水区。本研究突出了缺水的UYRB中特定集水区的河水 - 地下水相互作用和补给来源，为区域气候适应性水资源管理提供了关键见解。
