Despite the increasing depletion of the groundwater at the Zhangjiakou aquifer system in the northwest of Beijing-Tianjin-Hebei region,little information is available on the hydrological process of groundwater in this...Despite the increasing depletion of the groundwater at the Zhangjiakou aquifer system in the northwest of Beijing-Tianjin-Hebei region,little information is available on the hydrological process of groundwater in this region.In this study,we utilized water isotopes composition(51sO,5D and 3H)of groundwater,river and precipitation to identify the characteristics of hydrochemistry,groundwater age and recharge rates in different watersheds of the Zhangjiakou area.Results showed that the river water and groundwater could be characterized as HCO3-Mg Na,HCO3 CI-Na and HCO3-Mg Na,HCO3 CI-Na,HCO3 CI-Na Mg types,respectively.The 5D and 5180 values in precipitation were linearly correlated,which is similar to the Global Meteorological Water Line(GMWL).Furthermore,the decreasing values of the 6D and 5180 from precipitation to surface water and groundwater indicate that groundwater is mainly recharged by atmospheric precipitation.In addition,the variation of 3H concentration with depth suggests that groundwater shallower than around 100 m is generally modern water.In contrast,groundwater deeper around 100 m is a mixture of modern and old waters,which has longer residence times.Groundwater showed a relatively low tritium concentration in the confined aquifers,indicating the groundwater recharged might be relatively old groundwater of over 60 years.The flow velocity of the groundwater in the study area varied from 1.10 to 2.26 m/a,and the recharge rates ranged from 0.034 to 0.203 m/a.The obtained findings provide important insights into understanding the groundwater recharge sources and hydrochemistry in the Zhangjiakou area,in turn developing a sustainable groundwater management plan.展开更多
基金The National Major Science and Technology Program for Water Pollution Control and Treatment,No.2017ZX07101001-02。
文摘Despite the increasing depletion of the groundwater at the Zhangjiakou aquifer system in the northwest of Beijing-Tianjin-Hebei region,little information is available on the hydrological process of groundwater in this region.In this study,we utilized water isotopes composition(51sO,5D and 3H)of groundwater,river and precipitation to identify the characteristics of hydrochemistry,groundwater age and recharge rates in different watersheds of the Zhangjiakou area.Results showed that the river water and groundwater could be characterized as HCO3-Mg Na,HCO3 CI-Na and HCO3-Mg Na,HCO3 CI-Na,HCO3 CI-Na Mg types,respectively.The 5D and 5180 values in precipitation were linearly correlated,which is similar to the Global Meteorological Water Line(GMWL).Furthermore,the decreasing values of the 6D and 5180 from precipitation to surface water and groundwater indicate that groundwater is mainly recharged by atmospheric precipitation.In addition,the variation of 3H concentration with depth suggests that groundwater shallower than around 100 m is generally modern water.In contrast,groundwater deeper around 100 m is a mixture of modern and old waters,which has longer residence times.Groundwater showed a relatively low tritium concentration in the confined aquifers,indicating the groundwater recharged might be relatively old groundwater of over 60 years.The flow velocity of the groundwater in the study area varied from 1.10 to 2.26 m/a,and the recharge rates ranged from 0.034 to 0.203 m/a.The obtained findings provide important insights into understanding the groundwater recharge sources and hydrochemistry in the Zhangjiakou area,in turn developing a sustainable groundwater management plan.
