Groundwater resources in the North China Plain(NCP)are undergoing tremendous changes in response to the operation of groundwater exploitation reduction(GWER)project.To identify groundwater evolution in this complex co...Groundwater resources in the North China Plain(NCP)are undergoing tremendous changes in response to the operation of groundwater exploitation reduction(GWER)project.To identify groundwater evolution in this complex context,hierarchical cluster analysis(HCA)and principal component analysis(PCA)were combined to interpret an integrated dataset of stable isotopes and chemical data from four sampling campaigns in a pilot area of groundwater control.We proposed a novel HCA approach integrating stable isotopes and chemical signals,which successfully partitioned the groundwater samples into the unconfined and the confined water samples.Stable isotopic evidence showed that the lateral inflow and the surface water may contribute more to groundwater recharge in this region than local modern precipitation.The unconfined water's main hydrochemical types were Na type with mixed anions,and Na-Cl-SO_(4)type,while the confined water was mainly Na-Cl and Na-SO_(4)types.Geochemical processes mainly involved the dissolution/precipitation of halite,gypsum,Glauber's salt,feldspar,calcite and dolomite,as well as the cation exchange.PCA results showed that water-rock interaction(i.e.,salinity-based and alkalinity-based processes)predominated the hydrochemical evolution,along with local nitrate contamination resulting from fertilizers and domestic sewage.The GWER project regulated the natural evolution of unconfined water chemistry,and significantly reduced the unconfined water's salinity(mainly Na^(+),Mg^(2+),SO_(4)^(2-)).This may be attributed to upward leakage from low-salinity confined water at some parts of the aquifer.Additionally,insignificant changes in the confined water's salinity reflected that the impact of GWER on the confined aquifer was negligible.This study facilitates the groundwater classification effectively in the areas lack of geological data,and enhances the knowledge of groundwater chemical evolution in such a region where groundwater restoration is in progress,with important implications for groundwater sustainable management in similar basins worldwide.展开更多
A karst groundwater system ranks among the most sensitive and vulnerable types of groundwater systems.Coal mining and tunnel excavation can greatly change the natural hydrogeological flow system,groundwater-dependent ...A karst groundwater system ranks among the most sensitive and vulnerable types of groundwater systems.Coal mining and tunnel excavation can greatly change the natural hydrogeological flow system,groundwater-dependent vegetation,soil,as well as hydrology of surface water systems.Abandoned coal mine caves and proposed highway tunnels may have significant influences on groundwater systems.This study employs MODFLOW,a 3D finite-difference groundwater model software,to simulate the groundwater system's response to coal mining and tunnel excavation impact in Zhongliang Mountain,Chongqing,from 1948 to 2035.The results show a regional decline in groundwater levels within the study area following mining and tunnel construction.The groundwater flow system in the study area evolves from the Jialing River groundwater flow system to encompass the Jialing River,Moxinpo highway tunnel,Moxinpo,and the Liujiagou coal mine cave groundwater flow systems between 1948 and 2025.With the completion of tunnel construction,the groundwater level at the top of the tunnel is gradually restored to the water level in the natural state.The model also predicts groundwater level variations between 2025 and 2035.The groundwater level will rise further initially,however,it may take about 10 years for the system to stabilize and reach a new equilibrium.In light of these findings,it is advised that changes in groundwater flow systems caused by tunnel construction should be modeled prior to the practical construction.This approach is crucial for evaluating potential engineering and environmental implications.展开更多
基金the National Natural Science Foundation of China(Grant No.41901039)the Natural Science Foundation of Hebei Province(Grant No.D2022402013)the Department of Education of Hebei Province(Grant No,BJ2021014).
文摘Groundwater resources in the North China Plain(NCP)are undergoing tremendous changes in response to the operation of groundwater exploitation reduction(GWER)project.To identify groundwater evolution in this complex context,hierarchical cluster analysis(HCA)and principal component analysis(PCA)were combined to interpret an integrated dataset of stable isotopes and chemical data from four sampling campaigns in a pilot area of groundwater control.We proposed a novel HCA approach integrating stable isotopes and chemical signals,which successfully partitioned the groundwater samples into the unconfined and the confined water samples.Stable isotopic evidence showed that the lateral inflow and the surface water may contribute more to groundwater recharge in this region than local modern precipitation.The unconfined water's main hydrochemical types were Na type with mixed anions,and Na-Cl-SO_(4)type,while the confined water was mainly Na-Cl and Na-SO_(4)types.Geochemical processes mainly involved the dissolution/precipitation of halite,gypsum,Glauber's salt,feldspar,calcite and dolomite,as well as the cation exchange.PCA results showed that water-rock interaction(i.e.,salinity-based and alkalinity-based processes)predominated the hydrochemical evolution,along with local nitrate contamination resulting from fertilizers and domestic sewage.The GWER project regulated the natural evolution of unconfined water chemistry,and significantly reduced the unconfined water's salinity(mainly Na^(+),Mg^(2+),SO_(4)^(2-)).This may be attributed to upward leakage from low-salinity confined water at some parts of the aquifer.Additionally,insignificant changes in the confined water's salinity reflected that the impact of GWER on the confined aquifer was negligible.This study facilitates the groundwater classification effectively in the areas lack of geological data,and enhances the knowledge of groundwater chemical evolution in such a region where groundwater restoration is in progress,with important implications for groundwater sustainable management in similar basins worldwide.
基金supported by the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project(SKLGP2018Z018)the Research Project of China Railway Eryuan Engineering Group Co.,Ltd.(KDNQ203005).
文摘A karst groundwater system ranks among the most sensitive and vulnerable types of groundwater systems.Coal mining and tunnel excavation can greatly change the natural hydrogeological flow system,groundwater-dependent vegetation,soil,as well as hydrology of surface water systems.Abandoned coal mine caves and proposed highway tunnels may have significant influences on groundwater systems.This study employs MODFLOW,a 3D finite-difference groundwater model software,to simulate the groundwater system's response to coal mining and tunnel excavation impact in Zhongliang Mountain,Chongqing,from 1948 to 2035.The results show a regional decline in groundwater levels within the study area following mining and tunnel construction.The groundwater flow system in the study area evolves from the Jialing River groundwater flow system to encompass the Jialing River,Moxinpo highway tunnel,Moxinpo,and the Liujiagou coal mine cave groundwater flow systems between 1948 and 2025.With the completion of tunnel construction,the groundwater level at the top of the tunnel is gradually restored to the water level in the natural state.The model also predicts groundwater level variations between 2025 and 2035.The groundwater level will rise further initially,however,it may take about 10 years for the system to stabilize and reach a new equilibrium.In light of these findings,it is advised that changes in groundwater flow systems caused by tunnel construction should be modeled prior to the practical construction.This approach is crucial for evaluating potential engineering and environmental implications.
