School of Environmental Science and Engineering, Indian Institute of Technology Kharagpur, 721 302, India.
School of Environmental Science and Engineering, Indian Institute of Technology Kharagpur, 721 302, India; Geology and Geophysics, Indian Institute of Technology Kharagpur, 721 302, India; Applied Policy Advisory to Hydrogeosciences Group, Indian Institute of Technology, Kharagpur 721302, India.
Sci Total Environ. 2021 Dec 1;798:149198. doi: 10.1016/j.scitotenv.2021.149198. Epub 2021 Jul 21.
The global climate patterns like El Niño Southern Oscillation (ENSO) cycle and Indian Ocean Dipole (IOD) have impacts on surface water quality and groundwater recharge patterns. But the ENSO and IOD impacts on surface water-groundwater (SW-GW) interaction in terms of quality have not been studied. Therefore, the present study was conducted to delineate the impacts of ENSO and IOD on the SW-GW interaction process-induced groundwater quality of coastal aquifers of Sundarbans, by the application of isotopic signature, salinity content of groundwater and seawater in relation to rainfall variability. Study results revealed that the declining trend of rainfall potentially increases the seawater salinity. The rainfall pattern also positively correlates with the groundwater level (GWL) at a 5% level of significance observed from the wavelet analysis. The deficit in rainfall due to the El Niño is the possible reason for the declining GWL, which is giving rise to groundwater salinity. El Niño also affected the nearshore seawater salinity which was increased from 19 to 24 ppT. The study provides a surrogate understanding of the potential impact of El Niño in one of the most climatically vulnerable parts of the planet, while IOD impacts are not conclusive. In the scenario of depleted rainfall amount, groundwater abstraction practices need to be managed, otherwise, it could create a potential threat to the available drinking water resources in the present and future climate change scenarios.
全球气候模式，如厄尔尼诺南方涛动（ENSO）循环和印度洋偶极子（IOD），对地表水质量和地下水补给模式都有影响。但是，ENSO 和 IOD 对地表水-地下水（SW-GW）相互作用质量的影响尚未得到研究。因此，本研究通过应用同位素特征、地下水和海水的盐度与降雨量变化的关系，来描绘 ENSO 和 IOD 对孙德尔本斯沿海含水层 SW-GW 相互作用过程引起的地下水质量的影响。研究结果表明，降雨量的下降趋势可能会增加海水的盐度。从小波分析中观察到，降雨模式也与地下水位（GWL）呈正相关，在 5%的显著水平上相关。由于厄尔尼诺现象导致的降雨量不足是 GWL 下降的可能原因，这导致了地下水的盐度上升。厄尔尼诺现象还影响了近岸海水的盐度，从 19 增加到 24 ppt。本研究提供了对地球上最脆弱的气候区之一潜在影响的替代理解，而 IOD 的影响尚不确定。在降雨量减少的情况下，需要管理地下水开采，否则，在当前和未来的气候变化情景下，这可能会对现有的饮用水资源造成潜在威胁。
