Distinct groundwater recharge sources and geochemical evolution of two adjacent sub-basins in the lower Shule River Basin, northwest China

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• 作者：Liheng Wang ; Yanhui Dong ; Yueqing Xie ; Fan Song ; Yaqiang Wei…
• 关键词：Stable isotopes ; Hydrochemistry ; Groundwater recharge ; Arid regions ; China
• 刊名：Hydrogeology Journal
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：24
• 期：8
• 页码：1967-1979
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Hydrogeology; Hydrology/Water Resources; Geology; Water Quality/Water Pollution; Geophysics/Geodesy; Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution;
• 出版者：Springer Berlin Heidelberg
• ISSN：1435-0157
• 卷排序：24

文摘

Based on analysis of groundwater hydrogeochemical and isotopic data, this study aims to identify the recharge sources and understand geochemical evolution of groundwater along the downstream section of the Shule River, northwest China, including two sub-basins. Groundwater samples from the Tashi sub-basin show markedly depleted stable isotopes compared to those in the Guazhou sub-basin. This difference suggests that groundwater in the Tashi sub-basin mainly originates from meltwater in the Qilian Mountains, while the groundwater in the Guazhou sub-basin may be recharged by seepage of the Shule River water. During the groundwater flow process in the Tashi sub-basin, minerals within the aquifer material (e.g., halite, calcite, dolomite, gypsum) dissolve in groundwater. Mineral dissolution leads to strongly linear relationships between Na+ and Cl− and between Mg2++ Ca2+ and SO₄2− + HCO₃−, with stoichiometry ratios of approximately 1:1 in both cases. The ion-exchange reaction plays a dominant role in hydrogeochemical evolution of groundwater in the Guazhou sub-basin and causes a good linear relationship between (Mg2++ Ca2+)–(SO₄2− + HCO₃−) and (Na++ K+)–Cl− with a slope of −0.89 and also results in positive chloroalkaline indices CAI 1 and CAI 2. The scientific results have implications for groundwater management in the downstream section of Shule River. As an important irrigation district in Hexi Corridor, groundwater in the Guazhou sub-basin should be used sustainably and rationally because its recharge source is not as abundant as expected. It is recommended that the surface water should be used efficiently and routinely, while groundwater exploitation should be limited as much as possible.