Abstract
Groundwater is undoubtedly important for water supplies and eco-environment protection, especially for arid and semi-arid regions. Analyzing the characteristics and evolution of groundwater is significant for the rational management of groundwater resources. This study investigated the hydrogeochemical characteristics and evolutions of groundwater in the Delingha area, northeast of the Qaidam Basin, northwest China, with a total of 123 water samples, including 105 unconfined groundwater samples, 12 confined groundwater samples, and 6 surface water samples. Hydrochemical results showed that the unconfined and confined groundwater presented diversity in ion concentration. Total Dissolved Solids (TDS) of the unconfined groundwater increased from 146.5 to 8954 mg/L along the groundwater flow direction. The groundwater hydrochemical types were HCO3-Ca·Mg and HCO3·SO4-Ca·Mg in the mountain front area, SO4·HCO3-Ca·Mg and SO4·Cl-Ca·Mg types in the alluvial-lacustrine plain, and Cl·SO4-Na and Cl-Na types in the lacustrine plain. The saturation index showed that parts of the groundwater samples were supersaturated with carbonate minerals (calcite and dolomite); however, all the samples were undersaturated with evaporite minerals (halite and gypsum). Groundwater chemical evolution is mainly controlled by evaporite and carbonate mineral dissolutions, aluminosilicates weathering, and cation exchange.
Highlights
Water shortage has been a critical issue in many parts of the world, especially in arid and semi-arid areas [1,2,3,4]
A comprehensive analysis of hydrochemical data of 123 water samples in the Delingla area were conducted to provide a basis for understanding the major ions origins, distribution, and associated hydrogeochemical evolutions along the flow path and supporting the the local groundwater resource management
The results showed that groundwater hydrochemistry has obvious zoning distribution in this area
Summary
Water shortage has been a critical issue in many parts of the world, especially in arid and semi-arid areas [1,2,3,4]. Qaidam Basin, which is located in Northwest China, is a typical arid area [5]. Because of the lack of surface-water and precipitation, groundwater has been the main water resource in this area. Sustainable management of groundwater has become a critical issue for this area. Understanding the hydrochemical characteristics of the local groundwater could provide guidance for sustainable groundwater development [6]. Recent studies for the groundwater of Qaidam area have focused on the recharge source, circulation, hydrochemical characteristics, and hydrochemical evolution of the local groundwater [4,5].
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