Using hydrochemical and isotopic data to determine sources of recharge and groundwater evolution in an arid region: a case study in the upper–middle reaches of the Shule River basin, northwestern China

Abstract

Understanding sources of recharge and mechanisms for hydrogeochemical evolution of groundwater in the Shule River basin, an arid inland river basin in northwestern China, is essential for successful water resource management. Sources of water and associated groundwater recharge processes were investigated using hydrogeological, hydrogeochemical, and isotopic methods. The study area was divided into three parts: Changma, the Shule valley, and the Beishan area. The hydrogeochemical and isotopic analysis results show that groundwater in Changma mainly originated from precipitation in the Qilian Mountains. Lateral flow from Changma is the primary recharge mechanism, while direct recharge by infiltration of precipitation can be neglected in the Shule valley. Minerals within the aquifer material (e.g., halite, calcite, dolomite, and gypsum) dissolve into water that recharges the groundwater system. Therefore, strong linear relationships were found between Na ? and Cl -and between Ca 2?

Quantitative Analysis of Groundwater Recharge in an Arid Area, Northwest China

“…It denotes the errors (independent of each other) expected for each of the measured terms in the mass balance of the fluid and the dissolved constituents. In order to make readers to understand Equations (1), (2) and (4), we have done a simplified example to show the calculated process. In Figure 2, cell n have two discharge items and two recharge items, it means the both number of I n and J n is 2, q in and q nj denote the average fluxes from the ith (i = 1, 2) source into cell n and from cell n into cell j (j = 1, 2), and cell n have a source_Q n and a sink_W n .…”

“…Arid areas share some common features, including high temperatures, high evaporation rates, low and irregular precipitation, low surface runoff, and fragile ecological environments. Because of the scarcity and uncertainty of the surface water supply, groundwater contributes a considerable proportion of the total water resource in arid areas, and plays an important role as a water supply for drinking and irrigation [2,3].…”

The Source, Flow Rates, and Hydrochemical Evolution of Groundwater in an Alluvial Fan of Qilian Mountain, Northwest China

“…The lower values suggest the occurrence of secondary evaporation during rainfall, which is not surprising given the arid conditions in northwestern China. The LMWL calculated for the Qilian Mountains using the data from Yeniugou station is expressed as δD = 7.6δ 18 O + 12.4 [30]. were relatively higher than those in autumn, indicating that heavy stable isotopes were enriched in the spring water during the summer.…”

“…Since recharging waters possess the CFC concentrations in the atmosphere at the time of recharge, a comparison of the concentrations observed in groundwater to the historical concentrations documented for the atmosphere provides insights into groundwater age [27]. In recent years, many investigators have combined hydrogeochemical methods with isotopic and geochemical tracer techniques to determine the source of the groundwater, its rate of migration, its age and residence time, and its geochemical evolution along the subsurface flow path [28][29][30]. An understanding of these parameters is vital for the effective management of groundwater resource.…”

“…However, few studies have focused on the Shule River Basin, an area which is in need of more effective and sustainable management of its water resources. Wang et al [30] used hydrochemical and stable isotopic data to determine the recharge source and evolution of groundwater in the upper-middle reaches of the Shule River Basin. Guo et al [36] and He et al [37] assessed the groundwater evolution and recharge source in the middle reaches of the Yumen-Tashi and the lower reaches of the Guazhou Basin in the Shule River Basin.…”