Environmental isotopic study on the recharge and residence time of groundwater in the Heihe River Basin, northwestern China

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• 作者：Zongyu Chen ; Zhenlong Nie ; Guanghui Zhang ; Li Wan and Jianmei Shen
• 关键词：Arid regions ; Stable isotopes ; Radioactive isotopes ; Groundwater recharge ; Groundwater age
• 刊名：Hydrogeology Journal
• 出版年：2006
• 出版时间：December, 2006
• 年：2006
• 卷：14
• 期：8
• 页码：1635-1651
• 全文大小：715 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Hydrogeology
  Geology
  Waste Water Technology, Water Pollution Control, Water Management and Aquatic Pollution
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1435-0157

文摘

The recharge and origin of groundwater and its residence time were studied using environmental isotopic measurements in samples from the Heihe River Basin, China. δ18O and δD values of both river water and groundwater were within the same ranges as those found in the alluvial fan zone, and lay slightly above the local meteoric water line (δD=6.87δ18O+3.54). This finding indicated that mountain rivers substantially and rapidly contribute to the water resources in the southern and northern sub-basins. δ18O and δD values of groundwater in the unconfined aquifers of these sub-basins were close to each other. There was evidence of enrichment of heavy isotopes in groundwater due to evaporation. The most pronounced increase in the δ18O value occurred in agricultural areas, reflecting the admixture of irrigation return flow. Tritium results in groundwater samples from the unconfined aquifers gave evidence for ongoing recharge, with mean residence times of: less than 36 years in the alluvial fan zone; about 12–16 years in agricultural areas; and about 26 years in the Ejina oasis. In contrast, groundwater in the confined aquifers had 14C ages between 0 and 10 ka BP.