The Berg River Catchment based in the Western Cape Province,South Africa services the greater Cape Town area with water,subsequent to supplying the vast agricultural activities that exist in the middle and the lower r...The Berg River Catchment based in the Western Cape Province,South Africa services the greater Cape Town area with water,subsequent to supplying the vast agricultural activities that exist in the middle and the lower reaches.This study thus investigates the hydrogeochemical interactions between surface and groundwater in the Berg River Catchment with the aim of establishing trends and transfer of constituents between the surface and groundwater systems,investigates the role that geology plays in water chemistry as well as identifies the geochemical processes controlling surface and groundwater chemistry in the catchment.This study was carried out using three types of research designs namely i)experimental research design;ii)field research design and meta-analysis research design.Furthermore,the study made use of hydrochemical data ranging from 2003 to 2013 obtained from the National Water Monitoring Database owned and maintained by the Department of Water and Sanitation and data that were sampled in 2016 by authors and analyzed using the ICP-MS Technique Ground Water Chart,Arc-GIS and Geosoft(Oasis Montaj)were further employed to model the data.The results indicated that:i)in the Upper Berg there is not much interaction and transfer of constituents between surface and groundwater;ii)the Middle Berg,however,indicated a degree of interaction with the sharing of constituents between the two water systems and iii)the Lower Berg indicated only NaCl water type also noting that the area situated near the river mouth whereby there is the mixing of river and seawater.展开更多
Drinking water supplies in Ulaanbaatar, the capital of Mongolia, are completely dependent on groundwater sourced from pumping wells located in an alluvial plain of the Tuul River which flows through Ulaanbaatar. The i...Drinking water supplies in Ulaanbaatar, the capital of Mongolia, are completely dependent on groundwater sourced from pumping wells located in an alluvial plain of the Tuul River which flows through Ulaanbaatar. The interaction between groundwater in the alluvial plain and river surface water was investigated using a hydrological and multi-tracers approach. The observed groundwater contour map clearly shows that the Tuul River recharges the floodplain groundwater and groundwater flows from east to west. The similarity of chemical and stable isotopic compositions suggests that groundwater is mainly recharged by Tuul River water in the vicinity of the river. In addition, considering groundwater contours and chemical composition, groundwater in the northern and southern mountain sides contribute to floodplain groundwater. Stable isotopic information suggests that winter season precipita- tion also contributes to the groundwater, because groundwater in a specific region has a considerably lower isotopic ratio. Using the End Member Mixing Analysis applying oxygen-18, SiO2 and HCO3 as tracers, the contribution ratios of the Tuul River, groundwater in the northem and southern mountain regions, and winter season precipitation to floodplain groundwater are esti- mated to be 58% to 85%, 1% to 54%, 0% to 16%, and 0% to 12%, respectively.展开更多
Subterranean estuaries(STEs)are characterized by the mixing of terrestrial fresh groundwater and seawater in coastal aquifers.Although microorganisms are important components of coastal groundwater ecosystems and play...Subterranean estuaries(STEs)are characterized by the mixing of terrestrial fresh groundwater and seawater in coastal aquifers.Although microorganisms are important components of coastal groundwater ecosystems and play critical roles in biogeochemical transformations in STEs,limited information is available about how their community dynamics interact with hydrological,geochemical and environmental characteristics in STEs.Here,we studied bacterial and archaeal diversities and distributions with 16S rRNA-based Illumina MiSeq sequencing technology between surface water and groundwater in a karstic STE.Principal-coordinate analysis found that the bacterial and archaeal communities in the areas where algal blooms occurred were significantly separated from those in other stations without algal bloom occurrence.Canonical correspondence analysis showed that nutrients and salinity can explain the patterns of bacterial and archaeal community dynamics.The results suggest that hydrological,geochemical and environmental characteristics between surface water and groundwater likely control the bacterial and archaeal diversities and distributions in STEs.Furthermore,we found that some key species can utilize terrestrial pollutants such as nitrate and ammonia in STEs,indicating that these species(e.g.,Nitrosopumilus maritimus,Limnohabitans parvus and Simplicispira limi)may be excellent candidates for in situ degradation/remediation of coastal groundwater contaminations concerned with the nitrate and ammonia.Overall,this study reveals the coupling relationship between the microbial communities and hydrochemical environments in STEs,and provides a perspective of in situ degradation/remediation for coastal groundwater quality management.展开更多
Based on Investigation and Assessment on Rational Exploitation and Utilization of Groundwater Resources in Typical Areas of the Hexi Corridor, the thesis studies on groundwater and environmental problems arising from ...Based on Investigation and Assessment on Rational Exploitation and Utilization of Groundwater Resources in Typical Areas of the Hexi Corridor, the thesis studies on groundwater and environmental problems arising from the large-scale agricultural development projects in Shule River Basin. The thesis analyzes problems in exploiting and utilizing water resources, defines the function zoning of groundwater resources in key areas and evaluates them. Finally, the thesis uses three-dimensional unsteady flow simulation and regional social and economic development plan to study on the allocation of groundwater in Shule River Basin. A proposal for rational allocation of Shule River Basin water resources has been put forward.展开更多
Luan River is the main water source in Beijing-Tianjin-Hebei region,northern China,where the groundwater system is vulnerable and pollution issue is serious.It is significant for regional groundwater resources protect...Luan River is the main water source in Beijing-Tianjin-Hebei region,northern China,where the groundwater system is vulnerable and pollution issue is serious.It is significant for regional groundwater resources protection to identify the hydrogeochemistry evolution and affecting factors along flow direction occurred in the upper reaches,especially the surface water-groundwater(SWGW)conversion relationship.In this study,recharge,conversion and geochemistry evolution of SW and GW were elucidated based on physical-hydrochemical indicators and stable isotopes in 36 GW samples and 20 SW samples,which were collected in July 2019 and July 2020.The factor analysis was further utilized to determine the main factors responsible for regional hydrogeochemical evolution.Results indicate that GW recharged SW in plateau area,and SW and GW recharged each other in typical Alpine valley area.The hydrochemical types are HCO3-Ca·Mg and HCO3-Ca,and the hydrochemical evolution is dominated by weathering of silicate and carbonate minerals.The cation exchange adsorption has minor impact on groundwater hydrochemistry.The rise of SO42-and NO3-contents in groundwater is related to industrial and agricultural activities.The main controlling factors of SW hydrochemical components included recharge from groundwater,industrial and mining activities,explaining 90.04%of data variance.However,water-rock interaction,agricultural and domestic sewage are responsible for GW quality,accounting for 83.38%.展开更多
When evaluating hyporheic exchange in a flowing stream, it is inappropriate to directly compare stream stage with subsurface hydraulic head (h) to determine direction and magnitude of the gradient between the stream a...When evaluating hyporheic exchange in a flowing stream, it is inappropriate to directly compare stream stage with subsurface hydraulic head (h) to determine direction and magnitude of the gradient between the stream and the subsurface. In the case of moving water, it is invalid to ignore velocity and to assume that stage equals the net downward pressure on the streambed.? The Bernoulli equation describes the distribution of energy within flowing fluids and implies that net pressure decreases as a function of velocity, i.e., the Venturi Effect, which sufficiently reduces the pressure on the streambed to create the appearance of a downward gradient when in fact the gradient may be upward with stream flow drawing water from the subsurface to the surface. A field study correlating the difference between subsurface head and stream stage in a low-gradient stream indicates that the effect is present and significant: shallow subsurface head increases less quickly than stage while deeper subsurface head increases more quickly. These results can substantially improve conceptual models and simulations of hyporheic flow.展开更多
长江经济带是我国重要的水资源聚集区、水生态功能区,但是水环境污染和水资源消耗已成为其可持续发展的障碍。为推动长江经济带绿色高质量发展,本文旨在探究以水资源要素为中心考量长江经济带的资源分配如何影响绿色发展效率,同时厘清...长江经济带是我国重要的水资源聚集区、水生态功能区,但是水环境污染和水资源消耗已成为其可持续发展的障碍。为推动长江经济带绿色高质量发展,本文旨在探究以水资源要素为中心考量长江经济带的资源分配如何影响绿色发展效率,同时厘清长江经济带产业结构调整在其水资源要素影响绿色发展效率过程中发挥的重要作用。论文基于2003—2020年面板数据,运用超效率SBM(slack based measure)模型测算绿色发展效率,分析水资源总量、用水效率和水资源质量三重约束对长江经济带绿色发展效率的影响,并检验了产业结构调整的3个维度,即产业结构合理化、产业结构高级化以及产业结构软化的中介效应及其与水资源约束的交互效应。结果表明:1)水资源约束中用水效率对长江经济带绿色发展效率影响最大,表现为正向促进作用,促进力度表现出上游>中游>下游的特征;2)从中介效应来看,长江经济带全流域主要是产业结构软化在用水效率影响绿色经济发展时发挥了中介作用,分流域来看主要是产业结构高级化发挥了主要作用,产业结构高级化在上游地区水资源总量影响绿色发展效率时表现出了中介作用,在下游地区用水效率、水资源质量影响绿色发展效率过程中也表现出了中介效应;3)从交互效应来看,长江经济带全流域用水效率与产业结构高级化、产业结构软化之间均存在交互作用,此外还存在水量约束与产业结构合理化的交互效应,分区域来看,下游是交互效应作用范围最广的地区,用水效率与产业结构合理化、软化之间以及水量约束与产业结构合理化、高级化、软化之间均存在交互作用。展开更多
文摘The Berg River Catchment based in the Western Cape Province,South Africa services the greater Cape Town area with water,subsequent to supplying the vast agricultural activities that exist in the middle and the lower reaches.This study thus investigates the hydrogeochemical interactions between surface and groundwater in the Berg River Catchment with the aim of establishing trends and transfer of constituents between the surface and groundwater systems,investigates the role that geology plays in water chemistry as well as identifies the geochemical processes controlling surface and groundwater chemistry in the catchment.This study was carried out using three types of research designs namely i)experimental research design;ii)field research design and meta-analysis research design.Furthermore,the study made use of hydrochemical data ranging from 2003 to 2013 obtained from the National Water Monitoring Database owned and maintained by the Department of Water and Sanitation and data that were sampled in 2016 by authors and analyzed using the ICP-MS Technique Ground Water Chart,Arc-GIS and Geosoft(Oasis Montaj)were further employed to model the data.The results indicated that:i)in the Upper Berg there is not much interaction and transfer of constituents between surface and groundwater;ii)the Middle Berg,however,indicated a degree of interaction with the sharing of constituents between the two water systems and iii)the Lower Berg indicated only NaCl water type also noting that the area situated near the river mouth whereby there is the mixing of river and seawater.
基金part of the UNESCO-Chair on Sustainable Groundwater Management in Mongoliafinancially supported by UNESCO/Japan Funds-in-Trust Co-operation for the Promotion of International Cooperation and Mutual Understanding.
文摘Drinking water supplies in Ulaanbaatar, the capital of Mongolia, are completely dependent on groundwater sourced from pumping wells located in an alluvial plain of the Tuul River which flows through Ulaanbaatar. The interaction between groundwater in the alluvial plain and river surface water was investigated using a hydrological and multi-tracers approach. The observed groundwater contour map clearly shows that the Tuul River recharges the floodplain groundwater and groundwater flows from east to west. The similarity of chemical and stable isotopic compositions suggests that groundwater is mainly recharged by Tuul River water in the vicinity of the river. In addition, considering groundwater contours and chemical composition, groundwater in the northern and southern mountain sides contribute to floodplain groundwater. Stable isotopic information suggests that winter season precipita- tion also contributes to the groundwater, because groundwater in a specific region has a considerably lower isotopic ratio. Using the End Member Mixing Analysis applying oxygen-18, SiO2 and HCO3 as tracers, the contribution ratios of the Tuul River, groundwater in the northem and southern mountain regions, and winter season precipitation to floodplain groundwater are esti- mated to be 58% to 85%, 1% to 54%, 0% to 16%, and 0% to 12%, respectively.
基金The National Key R&D Program of China under contract No.2022YFE0209300the National Natural Science Foundation of China under contract No.42006152+1 种基金the Zhejiang Provincial Natural Science Foundation of China under contract No.LQ21D060005the 111 Project under contract No.BP0820020.
文摘Subterranean estuaries(STEs)are characterized by the mixing of terrestrial fresh groundwater and seawater in coastal aquifers.Although microorganisms are important components of coastal groundwater ecosystems and play critical roles in biogeochemical transformations in STEs,limited information is available about how their community dynamics interact with hydrological,geochemical and environmental characteristics in STEs.Here,we studied bacterial and archaeal diversities and distributions with 16S rRNA-based Illumina MiSeq sequencing technology between surface water and groundwater in a karstic STE.Principal-coordinate analysis found that the bacterial and archaeal communities in the areas where algal blooms occurred were significantly separated from those in other stations without algal bloom occurrence.Canonical correspondence analysis showed that nutrients and salinity can explain the patterns of bacterial and archaeal community dynamics.The results suggest that hydrological,geochemical and environmental characteristics between surface water and groundwater likely control the bacterial and archaeal diversities and distributions in STEs.Furthermore,we found that some key species can utilize terrestrial pollutants such as nitrate and ammonia in STEs,indicating that these species(e.g.,Nitrosopumilus maritimus,Limnohabitans parvus and Simplicispira limi)may be excellent candidates for in situ degradation/remediation of coastal groundwater contaminations concerned with the nitrate and ammonia.Overall,this study reveals the coupling relationship between the microbial communities and hydrochemical environments in STEs,and provides a perspective of in situ degradation/remediation for coastal groundwater quality management.
基金the project Survey and Assessment of Water Resources Exploitation and Utilization in Characteristic Areas of the Hexi Corridor
文摘Based on Investigation and Assessment on Rational Exploitation and Utilization of Groundwater Resources in Typical Areas of the Hexi Corridor, the thesis studies on groundwater and environmental problems arising from the large-scale agricultural development projects in Shule River Basin. The thesis analyzes problems in exploiting and utilizing water resources, defines the function zoning of groundwater resources in key areas and evaluates them. Finally, the thesis uses three-dimensional unsteady flow simulation and regional social and economic development plan to study on the allocation of groundwater in Shule River Basin. A proposal for rational allocation of Shule River Basin water resources has been put forward.
基金funded by the Ecological Civilization Demonstration Area Comprehensive Geological Survey Project“Hydrogeological Survey of Chengde Area”(No.DD20200522)the National Natural Science Foundation of China(Nos.41521001 and 42177078)the“111”Program of China(No.B18049).
文摘Luan River is the main water source in Beijing-Tianjin-Hebei region,northern China,where the groundwater system is vulnerable and pollution issue is serious.It is significant for regional groundwater resources protection to identify the hydrogeochemistry evolution and affecting factors along flow direction occurred in the upper reaches,especially the surface water-groundwater(SWGW)conversion relationship.In this study,recharge,conversion and geochemistry evolution of SW and GW were elucidated based on physical-hydrochemical indicators and stable isotopes in 36 GW samples and 20 SW samples,which were collected in July 2019 and July 2020.The factor analysis was further utilized to determine the main factors responsible for regional hydrogeochemical evolution.Results indicate that GW recharged SW in plateau area,and SW and GW recharged each other in typical Alpine valley area.The hydrochemical types are HCO3-Ca·Mg and HCO3-Ca,and the hydrochemical evolution is dominated by weathering of silicate and carbonate minerals.The cation exchange adsorption has minor impact on groundwater hydrochemistry.The rise of SO42-and NO3-contents in groundwater is related to industrial and agricultural activities.The main controlling factors of SW hydrochemical components included recharge from groundwater,industrial and mining activities,explaining 90.04%of data variance.However,water-rock interaction,agricultural and domestic sewage are responsible for GW quality,accounting for 83.38%.
文摘When evaluating hyporheic exchange in a flowing stream, it is inappropriate to directly compare stream stage with subsurface hydraulic head (h) to determine direction and magnitude of the gradient between the stream and the subsurface. In the case of moving water, it is invalid to ignore velocity and to assume that stage equals the net downward pressure on the streambed.? The Bernoulli equation describes the distribution of energy within flowing fluids and implies that net pressure decreases as a function of velocity, i.e., the Venturi Effect, which sufficiently reduces the pressure on the streambed to create the appearance of a downward gradient when in fact the gradient may be upward with stream flow drawing water from the subsurface to the surface. A field study correlating the difference between subsurface head and stream stage in a low-gradient stream indicates that the effect is present and significant: shallow subsurface head increases less quickly than stage while deeper subsurface head increases more quickly. These results can substantially improve conceptual models and simulations of hyporheic flow.
文摘长江经济带是我国重要的水资源聚集区、水生态功能区,但是水环境污染和水资源消耗已成为其可持续发展的障碍。为推动长江经济带绿色高质量发展,本文旨在探究以水资源要素为中心考量长江经济带的资源分配如何影响绿色发展效率,同时厘清长江经济带产业结构调整在其水资源要素影响绿色发展效率过程中发挥的重要作用。论文基于2003—2020年面板数据,运用超效率SBM(slack based measure)模型测算绿色发展效率,分析水资源总量、用水效率和水资源质量三重约束对长江经济带绿色发展效率的影响,并检验了产业结构调整的3个维度,即产业结构合理化、产业结构高级化以及产业结构软化的中介效应及其与水资源约束的交互效应。结果表明:1)水资源约束中用水效率对长江经济带绿色发展效率影响最大,表现为正向促进作用,促进力度表现出上游>中游>下游的特征;2)从中介效应来看,长江经济带全流域主要是产业结构软化在用水效率影响绿色经济发展时发挥了中介作用,分流域来看主要是产业结构高级化发挥了主要作用,产业结构高级化在上游地区水资源总量影响绿色发展效率时表现出了中介作用,在下游地区用水效率、水资源质量影响绿色发展效率过程中也表现出了中介效应;3)从交互效应来看,长江经济带全流域用水效率与产业结构高级化、产业结构软化之间均存在交互作用,此外还存在水量约束与产业结构合理化的交互效应,分区域来看,下游是交互效应作用范围最广的地区,用水效率与产业结构合理化、软化之间以及水量约束与产业结构合理化、高级化、软化之间均存在交互作用。
