Unequal virtual water transfer may aggravate local water scarcity risk.However,the quantitative confirmation of a clear geographic convergence between virtual water transfer and water scarcity risk remains undetermine...Unequal virtual water transfer may aggravate local water scarcity risk.However,the quantitative confirmation of a clear geographic convergence between virtual water transfer and water scarcity risk remains undetermined.We present an analytical framework that reveals the spatial matching between global water scarcity risk and virtual water trade inequality.This framework integrates a three-dimensional water scarcity risk assessment,hybrid input-output analysis,pollution trade term construction,and geographic convergence identification.The framework is applied to 123 countries for long-term validation from 1991 to 2021.We show that despite global improvements in water efficiency and security,countries exceeding the maximum water vulnerability threshold have increased by 50%.South Asia is the largest net exporter of virtual water.Central Asia exhibits the most pronounced virtual water trade inequality.To achieve the same economic growth,Central Asia needs to pay several times the local water consumption costs of developed regions(15.9−83.6 times,2021).In the past 30 years,the average geographic convergence index exceeded 0.8.Countries facing severe water scarcity also exhibit pronounced inequalities in virtual water trade,indicating that a significant geographic convergence relationship exists.Effectively responding to this unsustainable relationship necessitates balancing both domestic resource risk management and global virtual water trade regulation.展开更多
Water transport time lag in the Soil-Plant-Atmosphere Continuum(SPAC)significantly impacts ecosystem hydrology and plant water relations,yet the relative contributions of different segments(soil vs.plant)to the total ...Water transport time lag in the Soil-Plant-Atmosphere Continuum(SPAC)significantly impacts ecosystem hydrology and plant water relations,yet the relative contributions of different segments(soil vs.plant)to the total lag and their response mechanisms under drought remain unclear.This study aimed to quantitatively partition the total SPAC water transport time lag through controlled experiments,identify the dominant component driving the drought response,and compare coexisting tree species with contrasting hydraulic strategies:Platycladus orientalis and Quercus variabilis.We conducted potted plant isotope(δ^(2)H)labeling experiments under normal water and drought stress treatments for both species.Using high-frequency isotope sampling and synchronous sap flow monitoring,we quantified the total water transport time lag from the soil surface to canopy branches(T_(iso),based on initial isotope arrival)and the internal plant transport time lag(T_(sap),based on sap flow path integration).An independent laboratory soil mixing experiment determined the baseline soil mixing time lag(T_(mix)),and the lag associated with soil infiltration and root uptake initiation was estimated(T_(soil)=T_(iso)−T_(sap)).The physical mixing of old and new soil water introduced a baseline time lag(T_(mix))of approximately 8-12 h.Under normal water conditions,the internal plant lag(T_(sap):37-40 h)constituted the major part of the total lag(T_(iso):43-46 h),with the estimated soil process lag(T_(soil))being relatively short(3-9 h).Drought stress significantly prolonged the total time lag.Crucially,this increase was primarily driven by a dramatic increase in the internal plant transport time lag(T_(sap)):T_(sap) increased by 77 h(193%)for P.orientalis and 33 h(89%)for Q.variabilis.In contrast,the estimated soil process lag(T_(soil))showed minimal increase(or even decreased)under drought.Consequently,the increase in T_(sap) almost entirely accounted for the prolongation of T_(iso)(T_(iso) increased by 188%for P.orientalis and 63%for Q.variabilis).Furthermore,the shallow-rooted P.orientalis was more sensitive to drought in terms of internal time lag increase compared to the deep-rooted Q.variabilis.Our direct experimental evidence demonstrates that internal plant physiological and hydraulic processes,rather than soil processes,dominantly regulate the response of total SPAC water transport time lag to drought stress.Tree species with different hydraulic strategies exhibit distinct time lag response mechanisms.These findings challenge traditional perspectives potentially overemphasizing soil limitations and highlight the critical importance of understanding internal plant dynamics for accurately predicting the temporal responses of ecosystem water relations.展开更多
Reuse of irrigation water after appropriate filtration has emerged as one of the most important strategies for addressing global water scarcity and improving the sustainability of agricultural systems.This study revie...Reuse of irrigation water after appropriate filtration has emerged as one of the most important strategies for addressing global water scarcity and improving the sustainability of agricultural systems.This study reviews the research progress on filtration technologies and the reuse of secondary water through a comprehensive visual and bibliometric analysis of the relevant scientific literature.Using tools such as R Studio,VOSviewer,and the Bibliometrix R‐package,a total of 374 publications published between 2003 and 2024 were retrieved from the Web of Science database and systematically analyzed.The collected literature was examined with respect to publication trends,disciplinary distributions,leading journals,contributing countries,institutions,and authors.Additionally,an in-depth keyword analysis was conducted to explore co-occurrence networks,thematic clustering,and emerging research frontiers.The results indicate three distinct developmental stages in this field:a slow and exploratory phase beginning in 2003,followed by a period of moderate growth around 2013,and a rapid expansion phase that has been evident since 2018.Research outputs primarily span environmental sciences,engineering,water resources management,and agricultural sciences.The findings highlight an increasing global interest in sustainable water reuse and the need for continued innovation in filtration methods to enhance water quality and agricultural productivity.Future scientific efforts should emphasize the development of advanced,cost-effective filtration technologies,the reduction of environmental risks,and the promotion of large-scale water reuse practices to alleviate water shortages and support resilient agricultural systems.展开更多
The water resources surveying and hydrological is required to understand and manage the impacts of climate change on the water systems.This review discusses the ways in which such surveys can be used in improving clim...The water resources surveying and hydrological is required to understand and manage the impacts of climate change on the water systems.This review discusses the ways in which such surveys can be used in improving climate resilience,procedures,practices,and opportunities.The innovations of the traditional ground-based surveys into the modern hydrological survey are the current technologies,remote sensing,Geographic Information Systems(GIS),and real-time sensor networks,which allow scanning the water resources in an extensive,accurate,and timely way.These high-level methods would help manage water systems with substantial data in the prediction of floods,droughts and other water hazards caused by climate change.In addition,a hydrological survey plays a very crucial role during the climate adaptation and mitigation process since it illuminates the sustainable level of water use and the sustainability of the ecosystem.Despite the tremendous development in the use of survey techniques,there remain problems of data gaps,the high cost of using the technique,and data integration enhancement.The future of hydrological surveying is to take advantage of the emerging technologies,encourage more stakeholder cooperation,and sustainable practices to enhance access to and use of data.This review determines the significance of hydrological surveying in the construction of climate resilience and presents the contribution of how future improvements in technology and cooperation can empower the management of water resources in the climate change environment.展开更多
In this study,the effects of low-dose sodium hypochlorite disinfection on water quality and biofilm growth in drinking water distribution systems(DWDS)after ultrafiltration pretreatment was investigated.The influence ...In this study,the effects of low-dose sodium hypochlorite disinfection on water quality and biofilm growth in drinking water distribution systems(DWDS)after ultrafiltration pretreatment was investigated.The influence of pipeline hydraulic residence time(HRT)on disinfection efficiency,by-product formation,microbial activity,and biofilm growth were considered.The results show that both microbial activities and metabolite secretion were stimulated by increasing HRT,aggravating the potential risk of microbial pollution in DWDS.The enhanced microbial metabolism could further weaken disinfection efficiency by consuming extra residual Chlorine,after which the formation of disinfection by-products was facilitated.Residual Chlorine was found negatively correlated with HRT.With prolonging HRT from 5 to 40 h,the concentration of disinfection by-products(Chlorate,Chlorite,and Trichloromethane)was on a continuously increasing trend by 37%,140%,and 75%,respectively.But the water kept in pipeline still reliably satisfied the Standards for drinking water quality in China(GB5749–2022).Besides,more biofilm with denser morphologies developed on rubber pipeline gaskets rather than the iron/plastic ones.Rubber material was inappropriate for DWDS due to its potential risk of secondary biological pollution.Prolonging HRT also enhanced the accumulation of dominant bacteria(e.g.Bradyrhizobium and Obscuribacter)and decreased microbial diversity.展开更多
Major chemical ionic components in water serve as indicators of natural factors in the areas traversed by water bodies,and are thus widely used to elucidate key hydrogeochemical processes,including rock weathering,aqu...Major chemical ionic components in water serve as indicators of natural factors in the areas traversed by water bodies,and are thus widely used to elucidate key hydrogeochemical processes,including rock weathering,aquatic evaporation-crystallization,and the input of precipitation-derived materials into river basins.A total of 208 water samples were collected between August 2021 and August 2022 to investigate the hydrochemical characteristics and their influencing factors of the surface water and the groundwater in the Mingyong River Basin.To systematically analyze the data,we combined hydrogeochemical and statistical methods:descriptive statistics characterized ion concentration and physicochemical parameter distributions;Piper trilinear diagrams classified hydrochemical types;Pearson correlation analysis assessed ion-ion and ionTDS dependencies;Gibbs diagrams and ion ratio analysis identified solute sources;and the absolute principal component score-multiple linear regression(APCS-MLR)model quantified the contribution rates of different influencing factors.The results revealed that the dominant cations in the surface water and groundwater are Ca^(2+)and Mg^(2+),while the dominant anions are HCO_(3)^(-)and SO_(4)^(2-).The groundwater exhibits an extended residence time within rock strata,facilitating prolonged interaction with soluble minerals and intensifying the water-rock reaction process,thereby resulting in higher levels of electrical conductivity(EC),pH,and total dissolved solids(TDS)than those in the surface water.Secondly,the parameters of the surface water and groundwater indicate positive correlation.The weathering of rocks constitutes the primary solute source in the water of the basin.The hydrochemical composition of the basin water is primarily influenced by both carbonate and silicate rocks,with a minor contribution from evaporite rocks.The water bodies in the basin are affected by anthropogenic activities.The surface water is influenced by four sources,namely lixiviation-enrich,human activities,geological environmental,and unknown sources.The groundwater is influenced by five sources,namely lixiviation-enrich,primary geological,human activities,geological environmental,and unknown sources.展开更多
Sustainable water,energy and food(WEF)supplies are the bedrock upon which human society depends.Solar-driven interfacial evaporation,combined with electricity generation and cultivation,is a promising approach to miti...Sustainable water,energy and food(WEF)supplies are the bedrock upon which human society depends.Solar-driven interfacial evaporation,combined with electricity generation and cultivation,is a promising approach to mitigate the freshwater,energy and food crises.However,the performance of solar-driven systems decreases significantly during operation due to uncontrollable weather.This study proposes an integrated water/electricity cogeneration-cultivation system with superior thermal management.The energy storage evaporator,consisting of energy storage microcapsules/hydrogel composites,is optimally designed for sustainable desalination,achieving an evaporation rate of around 1.91 kg m^(-2)h^(-1).In the dark,heat released from the phase-change layer supported an evaporation rate of around 0.54kg m^(-2)h^(-1).Reverse electrodialysis harnessed the salinity-gradient energy enhanced during desalination,enabling the long-running WEC system to achieve a power output of~0.3 W m^(-2),which was almost three times higher than that of conventional seawater/surface water mixing.Additionally,an integrated crop irrigation platform utilized system drainage for real-time,on-demand wheat cultivation without secondary contaminants,facilitating seamless WEF integration.This work presents a novel approach to all-day solar water production,electricity generation and crop irrigation,offering a solution and blueprint for the sustainable development of WEF.展开更多
Forests are experiencing more frequent and intense wildfires in Canada,which pose considerable threats to water quantity and quality,particularly during the summer low-flow period when water demand is high.While the i...Forests are experiencing more frequent and intense wildfires in Canada,which pose considerable threats to water quantity and quality,particularly during the summer low-flow period when water demand is high.While the impacts of wildfire on hydrology have been widely assessed at the watershed scale,the underlying mechanisms of the responses of summer low flows remain poorly understood.In this study,we employed an integrated research framework that combines hydrometric monitoring with geochemical tracing to evaluate how the 2021 White Rock Lake Wildfire affected summer low flows,and to identify the underlying mechanisms governing these responses in the Okanagan Valley,British Columbia(BC),Canada.We found that(1)summer low flows,represented by Q90(flows exceeded at 90%of the time in summer)significantly increased following the wildfire(p<0.05);(2)summer low flows were primarily regulated by snow water in early summer(July),while dominated by groundwater in late summer(August and September);and(3)enhanced snow water contribution and reduced evapotranspiration(ET)were two primary contributors to the increased summer low flows.Our results provide insights for developing sustainable water management strategies for the region in the context of climate change and increasing forest disturbance.This study also demonstrates that the combination of hydrometric monitoring and geochemical tracing is an effective approach towards uncovering mechanisms that drive low-flow responses.展开更多
Effective groundwater management is crucial for economic sustainable development,particularly as climate change and population growth increase the uncertainty of aquifer dynamics.Due to limited geological data,Punjab&...Effective groundwater management is crucial for economic sustainable development,particularly as climate change and population growth increase the uncertainty of aquifer dynamics.Due to limited geological data,Punjab's complex hydrogeological conditions and Quaternary alluvial deposits present significant challenges for groundwater management.This study employs cost-effective numerical techniques as alternatives to traditional methods to safeguard groundwater quality,quantity,and accessibility.It introduces an edit-embedded transition frequency model that integrates regional datasets and utilizes algorithms such as GAMEAS,MCMOD,and TSIM to evaluate aquifer heterogeneity and simulate spatial variations using one-dimensional and three-dimensional Markov chains.Findings show that sand exhibits the highest self-transition(33.112 m),indicating strong stability,followed by silt,clay,and gravel,suggesting overall hydrofacies stability both horizontally and vertically.The model's predictions are largely consistent with actual material distribution,with a slight under-prediction of clay(-0.750%)and an over-prediction of sand(2.985%),which accounts for 58.77%of the aquifer material.It also highlights significant heterogeneity in the northern mountainous regions and minor variations in the south.The study emphasizes Punjab's severe water crisis,with groundwater reserves of 3502.3 BCM,declining water levels(0.38–33.62 m),and low hydraulic conductivity,urging government action on rainwater harvesting and sustainable groundwater management policies.展开更多
Aquaculture ponds have emerged as a significant contributor to greenhouse gas(GHG)emissions.We measured methane(CH_(4)),carbon dioxide(CO_(2)),and nitrous oxide(N_(2)O)emissions in ponds,all located in Jiangsu Provinc...Aquaculture ponds have emerged as a significant contributor to greenhouse gas(GHG)emissions.We measured methane(CH_(4)),carbon dioxide(CO_(2)),and nitrous oxide(N_(2)O)emissions in ponds,all located in Jiangsu Province,with different fish and management practices over an entire cycle.All ponds emitted these gases,with higher CH_(4) and N_(2)O levels during fish growth than stocking period.The highest CH_(4) and N_(2)O fluxes were found in the Crucian carp(Carassius auratus)pond with up to 16,512±3015μmol/(m^(2)·h)and 5.54±0.31μmol/(m^(2)·h),respectively.CH_(4) was the primary contributor to the global warming potential in traditional earthen ponds,accounting for an average contribution rate of 87.7%.The dissolved oxygen(DO)concentration was the water quality parameter that most significantly influenced the CO_(2)flux,while pH acted as its primary regulator.The GHG emission intensity per unit of fish production in traditional earthen ponds was 197 times higher than that in-pond raceway systems.Largemouth bass(Micropterus salmoides)and Crucian carp ponds exhibited CH_(4) diffusion fluxes at the sediment-water interface,which were>20 times higher than those at the water-air interface.Our results further suggest that stocking density and feed amount significantly influence the variations in GHG emissions among the ponds with the in-pond raceway system having low carbon emissions and being high yield aquaculture system compared to traditional earthen ponds.The water depth and DO concentration can be manipulated to reduce GHG emissions across the various interfaces.展开更多
Endowed with opportunities from both land and ocean,coastal areas attract expanding human populations and economic activities.At the same time,they face growing societal and environmental pressures from both the above...Endowed with opportunities from both land and ocean,coastal areas attract expanding human populations and economic activities.At the same time,they face growing societal and environmental pressures from both the above river catchments and the bordering sea due to climate change,ecosystem degradation,and expansion of built-up areas.Despite the accumulation of human population,economic activities,and environmental impacts,we lack social-ecological systems analysis on water-related risks to world’s coastal human population.To address this research gap,we analyze the spatial extent of six globally important water stressors to people within the world’s coastal zone(100 km from the coastal line)and classify this zone globally into 12 groups by distance from the coastline and elevation from the mean sea level.Adopting the approaches of the UN Sendai Framework and IPCC,we produce risk maps from the stressor maps by multiplying them with population exposure and vulnerability.For most risks,geographical hotspots are the Chinese coast,Bay of Bengal,Gujarat,and the Island of Java.The analysis reveals fundamental differences between water stressors and related risks,often mixed in scholarly literature.Both manifest specific geographic patterns and latitudinal profiles.Our study highlights the importance of high-resolution spatial analysis of vulnerability,exposure,and risks posed by water related stressors in the world’s coastal zone,in a manner prompted by key policy bodies to promote policy design and shared responsibility for managing stress-prone areas.展开更多
In the conventional water treatment process,algae have a propensity to breach the filter barriers and potentially seep into the water distribution system,leading to an elevation in taste and odor compounds(T&O com...In the conventional water treatment process,algae have a propensity to breach the filter barriers and potentially seep into the water distribution system,leading to an elevation in taste and odor compounds(T&O compounds).This investigation delved into the seasonal fluctuations of algae penetration and the production of T&O compounds within the treatment units of Reservoir Water Plant 1(W1)and River Water Plant 2(W2).The findings indicated that despite the application of the‘pre-oxidation,coagulation and sedimentation(PCS),sand filtration,and disinfection’process,certain robust-walled filamentous Cyanobacteria,Bacillariophyta species,and small Chlorophyta genera managed to bypass the filters.The leakage of algal cells during autumn at W1 was particularly striking,with a peak of 1,170,000 cells/L.The concurrent assessment of the potential for T&O compound formation revealed an alarming high potential for 2-methylisoborneol(2-MIB)in the water leaving the plants,with concentrations soaring to 197.20 ng/L at W1 in autumn and 54.78 ng/L at W2 in summer.This underscores the significant capacity of residual algal cells to generate T&O compounds.Tracking the retention and penetration dynamics of algal cells across each drinking water treatment stage is crucial for surface water treatment facilities to develop effective operational and management strategies,thereby enhancing the safety and quality of drinking water for the end consumer.展开更多
Using unscientific agricultural methods can harm human health by increasing harmful nitrate(NO_(3)−)levels in groundwater,as observed in the Yinchuan Plain.This research utilized hydrochemical data,dual isotopic data,...Using unscientific agricultural methods can harm human health by increasing harmful nitrate(NO_(3)−)levels in groundwater,as observed in the Yinchuan Plain.This research utilized hydrochemical data,dual isotopic data,the MixSIAR model,and the uncertainty index(UI90)to detect the potential sources of groundwater NO_(3)−,track NO_(3)−conversion processes,and calculate the apportionment of each groundwater NO_(3)−source in the agricultural lands of the Yinchuan Plain.The results show that soil organic nitrogen accounted for 49.4%,and N-fertilizers contributed 30.4%,making them the two main contributors to NO_(3)-contamination in groundwater.Long-term N-fertilization enhances soil organic nitrogen accumulation,resulting in NO_(3)−leaching into groundwater during irrigation.The highest uncertainty regarding soil organic nitrogen and N-fertilizers may stem from changes in groundwater flow patterns,unbalanced N-fertilization,irrigation,and precipitation.Denitrification is the dominant process,resulting in lower NO_(3)−concentrations in groundwater in most areas.As a result,most groundwater in the Yinchuan Plain is generally safe for human consumption,except the specific areas in Qingtongxia City and Wuzhong City.Flood irrigation can increase the leaching of NO_(3)−into groundwater,and the repeated recharge of groundwater contaminated with high NO_(3)−levels could also be a potential source of NO_(3)−contamination in agricultural areas.This research provides scientific guidance for sustainable groundwater management in the Yinchuan Plain,mitigating the risk of groundwater NO_(3)−pollution.展开更多
Although activated carbon filters are thought to be the best way to remove per-and polyfluorinated alkyl substances(PFAS),it is yet unknown how biofilms affect PFAS removal.This study first examined how the removal of...Although activated carbon filters are thought to be the best way to remove per-and polyfluorinated alkyl substances(PFAS),it is yet unknown how biofilms affect PFAS removal.This study first examined how the removal of PFAS in full-scale drinking water treatment plants(DWTPs)was impacted by biofilm from biological activated carbon(BAC)of varying depths and carbon ages.PFAS desorption from BAC was visible,but at this point,BAC could still remove dissolved organic matter(DOM)efficiently.Studies have demonstrated that the use of activated carbon filters can dramatically lower the content of PFAS in water,with the amount of PFAS reducing as the filter’s depth grows and its use duration increases.Additionally,pore-clogging becomes more noticeable as the biofilm ages,which reduces BAC’s capacity to eliminate PFAS and hinders PFAS desorption.Furthermore,the adsorption process of PFAS may be impeded by the secretion of biofilms,which are composed of proteins and polysaccharides.Based on the analysis above,it can be the adsorption of PFAS by BAC is significantly inhibited by biofilms,according to another research.This provides theoretical direction for improving the removal effectiveness of PFAS in DWTPs.展开更多
The most common aspect of water conveyance tunnel construction is the use of horizontal and sub-horizontal exploration drilling of headings of a tunnel to predict geology and groundwater conditions.The instability of ...The most common aspect of water conveyance tunnel construction is the use of horizontal and sub-horizontal exploration drilling of headings of a tunnel to predict geology and groundwater conditions.The instability of boreholes,extreme loss of circulation,and high-head inflow are also common in fractured strata,which often inhibit completion of probe holes and the reliability of coring,packer testing,and grouting tests.Casing,consequently,is a significant enabling technology to stabilize fractured intervals and has a hydraulic isolation under coupled mechanical and hydrogeological disturbances.The review is a synthesis of research and engineering experience on methods of casing to be used in horizontal drilling of fractured rock masses used in the exploration of water conveyance tunnels.The geological and working environment is initially outlined with a focus on fracture-adaptable instability processes and the special goings on of underground drilling,such as the restricted workspace,cuttings difficult to move,and fast movement of the competent and crushed regions.Types of casing systems are then listed,including both standard threaded steel strings and telescopic programs,and more specialized casing system types,including expandable casing,swellable sealing elements,and external casing packers.Special focus is made on the sealing of annulus in horizontal holes,wherein slurry loss,gravity segregation,and non-uniform borehole geometry usually worsen isolation.Lastly,the article suggests adaptive choice of strategy according to real-time drilling reaction,and research priorities,such as tunnel-specific performance measurements,coupled hydro-mechanical modelling,and field trials of sophisticated sealing material and data-driven choice making.展开更多
Groundwater level(GWL)is a key indicator used to accurately assess groundwater resources and form the foundation for ef-fective groundwater management.This paper integrates a Gate Recurrent Unit(GRU)model with a Multi...Groundwater level(GWL)is a key indicator used to accurately assess groundwater resources and form the foundation for ef-fective groundwater management.This paper integrates a Gate Recurrent Unit(GRU)model with a Multi-head Self-attention mechan-ism(MSAM-GRU)to simulate GWLs in both confined and unconfined aquifers simultaneously.The model innovatively captures the lag times between GWLs in the unconfined aquifer and precipitation,as well as between GWLs in the confined aquifer and the upper aquifer.We have assessed the effectiveness of the proposed model using a case study in the Beijing Plain,China from January 2005 to December 2020.With the consideration of lag times,the results indicated that the MSAM-GRU model exhibits a maximum 67%and 73%reduction in RMSE compared to the Attention mechanism-GRU(AM-GRU)and GRU model,respectively.MSAM-GRU model exhibited a 31%reduction in RMSE and a 0.12 increase in R^(2) compared to the same model that do not account for lag time.In Region I,the shortest lag time of GWL in the unconfined aquifer was two months,while that in the confined aquifer was three months,indicating a longer delayed response in the confined aquifer.MSAM-GRU model considering lag time,was then applied to simulate the GWLs in the unconfined aquifer under different scenarios and to analyze whether GWL fluctuations affect subway operations.The simulation res-ults showed that under the scenario 1,the GWL in the unconfined aquifer would rise above the depth of subway station floor,threaten-ing the operation of subways.This study can provide reliable technical support for the accurate simulation of GWLs in multi-aquifer systems.展开更多
The discharge of micro-polluted water from sources such as agricultural runoff,urban stormwater,and treated effluents presents significant challenges to aquatic ecosystems.Constructed wetlands(CWs)have gained recog-ni...The discharge of micro-polluted water from sources such as agricultural runoff,urban stormwater,and treated effluents presents significant challenges to aquatic ecosystems.Constructed wetlands(CWs)have gained recog-nition as an eco-friendly solution for removing pollutants from various wastewater sources and are increasingly applied for micro-polluted water treatment.By reviewing 78 full-scale CW studies from Web of Science,it is summarized that the ranges of ammonium nitrogen(NH4+-N)concentrations in runoff,wastewater treatment plant effluent and polluted river were 0.1–6.6,0.3–12.3,and 0.2–41.1 mg/L,respectively.The ranges of ni-trate nitrogen concentrations were 0.2–14.2,0–5.7,and 0–2.6 mg/L,respectively.Removal efficiencies of CWs for micro-polluted water varied by CW types.The total nitrogen removal efficiencies for subsurface-flow CWs,free-water surface-flow CWs,and hybrid CWs ranged from 27.4%to 66.5%,16.8%to 89.8%,and 19.4%to 88.2%,respectively.The NH4+-N removal efficiencies ranged from 34.2%to 73.6%,38.4%to 89.4%and 13.5%to 94.2%,respectively.Additionally,other factors influencing contaminant removal efficiency such as hydraulic retention time,vegetation types,redox micro-environment and influent water quality were evaluated.Based on these findings,two strategies for improving the purification performance of CWs were proposed:the selection of incorporating electron donor substrates and the optimization of operation parameters.This paper serves as a synthesis of information to guide future research and full-scale CW applications in micro-polluted water treatment.展开更多
Groundwater modeling remains challenging due to heterogeneity and complexity of aquifer systems,necessitating endeavors to quantify Groundwater Levels(GWL)dynamics to inform policymakers and hydrogeologists.This study...Groundwater modeling remains challenging due to heterogeneity and complexity of aquifer systems,necessitating endeavors to quantify Groundwater Levels(GWL)dynamics to inform policymakers and hydrogeologists.This study introduces a novel Fuzzy Nonlinear Additive Regression(FNAR)model to predict monthly GWL in an unconfined aquifer in eastern Iran,using a 19-year(1998–2017)dataset from 11 piezometric wells.Under three distinct scenarios with progressively increasing input complexity,the study utilized readily available climate data,including Precipitation(Prc),Temperature(Tave),Relative Humidity(RH),and Evapotranspiration(ETo).The dataset was split into training(70%)and validation(30%)subsets.Results showed that among three input scenarios,Scenario 3(Sc3,incorporating all four variables)achieved the best predictive performance,with RMSE ranging from 0.305 m to 0.768 m,MAE from 0.203 m to 0.522 m,NSE from 0.661 to 0.980,and PBIAS from 0.771%to 0.981%,indicating low bias and high reliability.However,Sc2(excluding ETo)with RMSE ranging from 0.4226 m to 0.9909 m,MAE from 0.3418 m to 0.8173 m,NSE from 0.2831 to 0.9674,and PBIAS from−0.598%to 0.968%across different months offers practical advantages in data-scarce settings.The FNAR model outperforms conventional Fuzzy Least Squares Regression(FLSR)and holds promise for GWL forecasting in data-scarce regions where physical or numerical models are impractical.Future research should focus on integrating FNAR with deep learning algorithms and real-time data assimilation expanding applications across diverse hydrogeological settings.展开更多
Accurate water budget closure is critical for sustainable water resource management facing increased pressures from climate change and human activities.Although error reduction methods for individual water balance com...Accurate water budget closure is critical for sustainable water resource management facing increased pressures from climate change and human activities.Although error reduction methods for individual water balance components have advanced,persistent biases remain due to the independent development of datasets,impacting basin scale water budget balance.In this research,we analyzed the mathematical origin of the bias between water budget components and developed a new basin-scale water balance calibration method that redistributes errors across components while enforcing water balance constraints.Validation confirms systematic improvements,with reduced RMSE(Precipitation:-2.29 mm/month;ET:-1.34 mm/month)and increased R2 against in situ observations.Applied to the Jinghe River Basin(2000−2019),the calibrated data reveal declining precipitation(-1.70 mm/year)and evapotranspiration(-1.84 mm/year)alongside slightly increasing runoff(0.20 mm/year in basin depth),signaling a drying trend.Land cover changes—marked by cropland loss(-3,497 km^(2))and forest(+720 km^(2))and grassland(+2,776 km^(2))expansion—reflect improved water consumption requirements by ecosystem,raising concerns for water retention and ecosystem stability.The method is particularly effective for ungauged basins with sparse ground data and underscores the need for integrated land-water management to enhance long-term resilience.展开更多
As a major source of freshwater in Central Asia,Tajikistan is endowed with abundant glaciers and water resources.However,the country faces multiple challenges,including accelerated glacier retreat,complex inter-govern...As a major source of freshwater in Central Asia,Tajikistan is endowed with abundant glaciers and water resources.However,the country faces multiple challenges,including accelerated glacier retreat,complex inter-government water resource management,and inefficient water use.Existing research has predominantly focused on individual hydrological processes,such as glacier retreat,snow cover change,or transboundary water issues,but it has yet to fully capture the overall complexity of water system.Tajikistan’s water system functions as an integrated whole from mountain runoff to downstream supply,but a comprehensive study of its water resource has yet to be conducted.To address this research gap,this study systematically examined the status,challenges,and sustainable management strategies of Tajikistan’s water resources based on a literature review,remote sensing data analysis,and case studies.Despite Tajikistan’s relative abundance of water resources,global warming is accelerating glacier melting and altering the hydrological cycles,which have resulted in unstable runoff patterns and heightened risks of extreme events.In Tajikistan,outdated infrastructure and poor management are primary causes of low water-use efficiency in the agricultural sector,which accounts for 85.00%of the total water withdrawals.At the governance level,Tajikistan faces challenges in balancing the water-energy-food nexus and transboundary water resource issues.To address these issues,this study proposes core paths for Tajikistan to achieve sustainable water resource management,such as accelerating technological innovation,promoting water-saving agricultural technologies,improving water resource utilization efficiency,and establishing a community participation-based comprehensive management framework.Additionally,strengthening cross-border cooperation and improving real-time monitoring systems have been identified as critical steps to advance sustainable water resource utilization and evidence-based decision-making in Tajikistan and across Central Asia.展开更多
基金supported by National Natural Science Foundation of China(Grant No.52279027)National Key R&D Program of China(Grant No.2021YFC3200201)+1 种基金Key Research Project on Decision Consultation of the Strategic Development Department of China Association for Science and Technology(Grant No.2023070615CG111504)China Engineering Science and Technology Development Strategy Henan Research Institute Strategic Consulting Research Project(Grant No.2024HENYB01).
文摘Unequal virtual water transfer may aggravate local water scarcity risk.However,the quantitative confirmation of a clear geographic convergence between virtual water transfer and water scarcity risk remains undetermined.We present an analytical framework that reveals the spatial matching between global water scarcity risk and virtual water trade inequality.This framework integrates a three-dimensional water scarcity risk assessment,hybrid input-output analysis,pollution trade term construction,and geographic convergence identification.The framework is applied to 123 countries for long-term validation from 1991 to 2021.We show that despite global improvements in water efficiency and security,countries exceeding the maximum water vulnerability threshold have increased by 50%.South Asia is the largest net exporter of virtual water.Central Asia exhibits the most pronounced virtual water trade inequality.To achieve the same economic growth,Central Asia needs to pay several times the local water consumption costs of developed regions(15.9−83.6 times,2021).In the past 30 years,the average geographic convergence index exceeded 0.8.Countries facing severe water scarcity also exhibit pronounced inequalities in virtual water trade,indicating that a significant geographic convergence relationship exists.Effectively responding to this unsustainable relationship necessitates balancing both domestic resource risk management and global virtual water trade regulation.
基金financial supports from the National Science Foundation of China(42277062,41977149 and 42230714).
文摘Water transport time lag in the Soil-Plant-Atmosphere Continuum(SPAC)significantly impacts ecosystem hydrology and plant water relations,yet the relative contributions of different segments(soil vs.plant)to the total lag and their response mechanisms under drought remain unclear.This study aimed to quantitatively partition the total SPAC water transport time lag through controlled experiments,identify the dominant component driving the drought response,and compare coexisting tree species with contrasting hydraulic strategies:Platycladus orientalis and Quercus variabilis.We conducted potted plant isotope(δ^(2)H)labeling experiments under normal water and drought stress treatments for both species.Using high-frequency isotope sampling and synchronous sap flow monitoring,we quantified the total water transport time lag from the soil surface to canopy branches(T_(iso),based on initial isotope arrival)and the internal plant transport time lag(T_(sap),based on sap flow path integration).An independent laboratory soil mixing experiment determined the baseline soil mixing time lag(T_(mix)),and the lag associated with soil infiltration and root uptake initiation was estimated(T_(soil)=T_(iso)−T_(sap)).The physical mixing of old and new soil water introduced a baseline time lag(T_(mix))of approximately 8-12 h.Under normal water conditions,the internal plant lag(T_(sap):37-40 h)constituted the major part of the total lag(T_(iso):43-46 h),with the estimated soil process lag(T_(soil))being relatively short(3-9 h).Drought stress significantly prolonged the total time lag.Crucially,this increase was primarily driven by a dramatic increase in the internal plant transport time lag(T_(sap)):T_(sap) increased by 77 h(193%)for P.orientalis and 33 h(89%)for Q.variabilis.In contrast,the estimated soil process lag(T_(soil))showed minimal increase(or even decreased)under drought.Consequently,the increase in T_(sap) almost entirely accounted for the prolongation of T_(iso)(T_(iso) increased by 188%for P.orientalis and 63%for Q.variabilis).Furthermore,the shallow-rooted P.orientalis was more sensitive to drought in terms of internal time lag increase compared to the deep-rooted Q.variabilis.Our direct experimental evidence demonstrates that internal plant physiological and hydraulic processes,rather than soil processes,dominantly regulate the response of total SPAC water transport time lag to drought stress.Tree species with different hydraulic strategies exhibit distinct time lag response mechanisms.These findings challenge traditional perspectives potentially overemphasizing soil limitations and highlight the critical importance of understanding internal plant dynamics for accurately predicting the temporal responses of ecosystem water relations.
文摘Reuse of irrigation water after appropriate filtration has emerged as one of the most important strategies for addressing global water scarcity and improving the sustainability of agricultural systems.This study reviews the research progress on filtration technologies and the reuse of secondary water through a comprehensive visual and bibliometric analysis of the relevant scientific literature.Using tools such as R Studio,VOSviewer,and the Bibliometrix R‐package,a total of 374 publications published between 2003 and 2024 were retrieved from the Web of Science database and systematically analyzed.The collected literature was examined with respect to publication trends,disciplinary distributions,leading journals,contributing countries,institutions,and authors.Additionally,an in-depth keyword analysis was conducted to explore co-occurrence networks,thematic clustering,and emerging research frontiers.The results indicate three distinct developmental stages in this field:a slow and exploratory phase beginning in 2003,followed by a period of moderate growth around 2013,and a rapid expansion phase that has been evident since 2018.Research outputs primarily span environmental sciences,engineering,water resources management,and agricultural sciences.The findings highlight an increasing global interest in sustainable water reuse and the need for continued innovation in filtration methods to enhance water quality and agricultural productivity.Future scientific efforts should emphasize the development of advanced,cost-effective filtration technologies,the reduction of environmental risks,and the promotion of large-scale water reuse practices to alleviate water shortages and support resilient agricultural systems.
文摘The water resources surveying and hydrological is required to understand and manage the impacts of climate change on the water systems.This review discusses the ways in which such surveys can be used in improving climate resilience,procedures,practices,and opportunities.The innovations of the traditional ground-based surveys into the modern hydrological survey are the current technologies,remote sensing,Geographic Information Systems(GIS),and real-time sensor networks,which allow scanning the water resources in an extensive,accurate,and timely way.These high-level methods would help manage water systems with substantial data in the prediction of floods,droughts and other water hazards caused by climate change.In addition,a hydrological survey plays a very crucial role during the climate adaptation and mitigation process since it illuminates the sustainable level of water use and the sustainability of the ecosystem.Despite the tremendous development in the use of survey techniques,there remain problems of data gaps,the high cost of using the technique,and data integration enhancement.The future of hydrological surveying is to take advantage of the emerging technologies,encourage more stakeholder cooperation,and sustainable practices to enhance access to and use of data.This review determines the significance of hydrological surveying in the construction of climate resilience and presents the contribution of how future improvements in technology and cooperation can empower the management of water resources in the climate change environment.
基金supported by the National Natural Science Foundation of China(Nos.52170070,52400022,and 52200088)the Youth S&T Talent Support Programme of Guangdong Provincial Association for Science and Technology(GDSTA)(No.SKXRC202406)+1 种基金the“One hundred Youth”Science and Technology Plan,Guangdong University of Technology,China(No.263113906)China Postdoctoral Science Foundation(No.2023M740754).
文摘In this study,the effects of low-dose sodium hypochlorite disinfection on water quality and biofilm growth in drinking water distribution systems(DWDS)after ultrafiltration pretreatment was investigated.The influence of pipeline hydraulic residence time(HRT)on disinfection efficiency,by-product formation,microbial activity,and biofilm growth were considered.The results show that both microbial activities and metabolite secretion were stimulated by increasing HRT,aggravating the potential risk of microbial pollution in DWDS.The enhanced microbial metabolism could further weaken disinfection efficiency by consuming extra residual Chlorine,after which the formation of disinfection by-products was facilitated.Residual Chlorine was found negatively correlated with HRT.With prolonging HRT from 5 to 40 h,the concentration of disinfection by-products(Chlorate,Chlorite,and Trichloromethane)was on a continuously increasing trend by 37%,140%,and 75%,respectively.But the water kept in pipeline still reliably satisfied the Standards for drinking water quality in China(GB5749–2022).Besides,more biofilm with denser morphologies developed on rubber pipeline gaskets rather than the iron/plastic ones.Rubber material was inappropriate for DWDS due to its potential risk of secondary biological pollution.Prolonging HRT also enhanced the accumulation of dominant bacteria(e.g.Bradyrhizobium and Obscuribacter)and decreased microbial diversity.
基金funded by the National Natural Science Foundation of China(No.42061012)the Open Project of Yunnan Province’s First Class Discipline of Soil and Water Conservation and Desertification Control(SBK20240019)。
文摘Major chemical ionic components in water serve as indicators of natural factors in the areas traversed by water bodies,and are thus widely used to elucidate key hydrogeochemical processes,including rock weathering,aquatic evaporation-crystallization,and the input of precipitation-derived materials into river basins.A total of 208 water samples were collected between August 2021 and August 2022 to investigate the hydrochemical characteristics and their influencing factors of the surface water and the groundwater in the Mingyong River Basin.To systematically analyze the data,we combined hydrogeochemical and statistical methods:descriptive statistics characterized ion concentration and physicochemical parameter distributions;Piper trilinear diagrams classified hydrochemical types;Pearson correlation analysis assessed ion-ion and ionTDS dependencies;Gibbs diagrams and ion ratio analysis identified solute sources;and the absolute principal component score-multiple linear regression(APCS-MLR)model quantified the contribution rates of different influencing factors.The results revealed that the dominant cations in the surface water and groundwater are Ca^(2+)and Mg^(2+),while the dominant anions are HCO_(3)^(-)and SO_(4)^(2-).The groundwater exhibits an extended residence time within rock strata,facilitating prolonged interaction with soluble minerals and intensifying the water-rock reaction process,thereby resulting in higher levels of electrical conductivity(EC),pH,and total dissolved solids(TDS)than those in the surface water.Secondly,the parameters of the surface water and groundwater indicate positive correlation.The weathering of rocks constitutes the primary solute source in the water of the basin.The hydrochemical composition of the basin water is primarily influenced by both carbonate and silicate rocks,with a minor contribution from evaporite rocks.The water bodies in the basin are affected by anthropogenic activities.The surface water is influenced by four sources,namely lixiviation-enrich,human activities,geological environmental,and unknown sources.The groundwater is influenced by five sources,namely lixiviation-enrich,primary geological,human activities,geological environmental,and unknown sources.
基金supported by the National Natural Science Foundation of China(No.52070057)China Postdoctoral Science Foundation(No.2023M730855)Heilongjiang Postdoctoral Fund(No.LBH-Z22183)for financial support。
文摘Sustainable water,energy and food(WEF)supplies are the bedrock upon which human society depends.Solar-driven interfacial evaporation,combined with electricity generation and cultivation,is a promising approach to mitigate the freshwater,energy and food crises.However,the performance of solar-driven systems decreases significantly during operation due to uncontrollable weather.This study proposes an integrated water/electricity cogeneration-cultivation system with superior thermal management.The energy storage evaporator,consisting of energy storage microcapsules/hydrogel composites,is optimally designed for sustainable desalination,achieving an evaporation rate of around 1.91 kg m^(-2)h^(-1).In the dark,heat released from the phase-change layer supported an evaporation rate of around 0.54kg m^(-2)h^(-1).Reverse electrodialysis harnessed the salinity-gradient energy enhanced during desalination,enabling the long-running WEC system to achieve a power output of~0.3 W m^(-2),which was almost three times higher than that of conventional seawater/surface water mixing.Additionally,an integrated crop irrigation platform utilized system drainage for real-time,on-demand wheat cultivation without secondary contaminants,facilitating seamless WEF integration.This work presents a novel approach to all-day solar water production,electricity generation and crop irrigation,offering a solution and blueprint for the sustainable development of WEF.
基金the China Scholarship Council(CSC)the Uplifting Reciprocal Research Scholarship Program for sponsoring Shixuan Lyu+1 种基金supported by MITACS Accelerate(No.IT39116)the Okanagan Basin Water Board water conservation and quality improvement grant program。
文摘Forests are experiencing more frequent and intense wildfires in Canada,which pose considerable threats to water quantity and quality,particularly during the summer low-flow period when water demand is high.While the impacts of wildfire on hydrology have been widely assessed at the watershed scale,the underlying mechanisms of the responses of summer low flows remain poorly understood.In this study,we employed an integrated research framework that combines hydrometric monitoring with geochemical tracing to evaluate how the 2021 White Rock Lake Wildfire affected summer low flows,and to identify the underlying mechanisms governing these responses in the Okanagan Valley,British Columbia(BC),Canada.We found that(1)summer low flows,represented by Q90(flows exceeded at 90%of the time in summer)significantly increased following the wildfire(p<0.05);(2)summer low flows were primarily regulated by snow water in early summer(July),while dominated by groundwater in late summer(August and September);and(3)enhanced snow water contribution and reduced evapotranspiration(ET)were two primary contributors to the increased summer low flows.Our results provide insights for developing sustainable water management strategies for the region in the context of climate change and increasing forest disturbance.This study also demonstrates that the combination of hydrometric monitoring and geochemical tracing is an effective approach towards uncovering mechanisms that drive low-flow responses.
基金supported by the K.C.Wong Education Foundation(GJTD-2020-14)the National Natural Science Foundation of China(42071245)+3 种基金Third Xinjiang Scientific Expedition Program(2021XJKK1400)the China-Pakistan Joint Research Center on Earth Sciences that supported the implementation of this studythe Chinese Academy of Sciences(CAS)the CSC Scholarship for Young Talents(Doctor Program)for the financial support of this study。
文摘Effective groundwater management is crucial for economic sustainable development,particularly as climate change and population growth increase the uncertainty of aquifer dynamics.Due to limited geological data,Punjab's complex hydrogeological conditions and Quaternary alluvial deposits present significant challenges for groundwater management.This study employs cost-effective numerical techniques as alternatives to traditional methods to safeguard groundwater quality,quantity,and accessibility.It introduces an edit-embedded transition frequency model that integrates regional datasets and utilizes algorithms such as GAMEAS,MCMOD,and TSIM to evaluate aquifer heterogeneity and simulate spatial variations using one-dimensional and three-dimensional Markov chains.Findings show that sand exhibits the highest self-transition(33.112 m),indicating strong stability,followed by silt,clay,and gravel,suggesting overall hydrofacies stability both horizontally and vertically.The model's predictions are largely consistent with actual material distribution,with a slight under-prediction of clay(-0.750%)and an over-prediction of sand(2.985%),which accounts for 58.77%of the aquifer material.It also highlights significant heterogeneity in the northern mountainous regions and minor variations in the south.The study emphasizes Punjab's severe water crisis,with groundwater reserves of 3502.3 BCM,declining water levels(0.38–33.62 m),and low hydraulic conductivity,urging government action on rainwater harvesting and sustainable groundwater management policies.
基金supported by the National Key Research and Development Program of China(No.SQ2024YFE0102696)the Provincial Science and Technology Innovative Program for Carbon Peak and Carbon Neutrality of Jiangsu of China(No.BE2022422)supported by the TÜBITAK program BIDEB2232(No.118C250).
文摘Aquaculture ponds have emerged as a significant contributor to greenhouse gas(GHG)emissions.We measured methane(CH_(4)),carbon dioxide(CO_(2)),and nitrous oxide(N_(2)O)emissions in ponds,all located in Jiangsu Province,with different fish and management practices over an entire cycle.All ponds emitted these gases,with higher CH_(4) and N_(2)O levels during fish growth than stocking period.The highest CH_(4) and N_(2)O fluxes were found in the Crucian carp(Carassius auratus)pond with up to 16,512±3015μmol/(m^(2)·h)and 5.54±0.31μmol/(m^(2)·h),respectively.CH_(4) was the primary contributor to the global warming potential in traditional earthen ponds,accounting for an average contribution rate of 87.7%.The dissolved oxygen(DO)concentration was the water quality parameter that most significantly influenced the CO_(2)flux,while pH acted as its primary regulator.The GHG emission intensity per unit of fish production in traditional earthen ponds was 197 times higher than that in-pond raceway systems.Largemouth bass(Micropterus salmoides)and Crucian carp ponds exhibited CH_(4) diffusion fluxes at the sediment-water interface,which were>20 times higher than those at the water-air interface.Our results further suggest that stocking density and feed amount significantly influence the variations in GHG emissions among the ponds with the in-pond raceway system having low carbon emissions and being high yield aquaculture system compared to traditional earthen ponds.The water depth and DO concentration can be manipulated to reduce GHG emissions across the various interfaces.
基金support from the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation programme(Grant agreement No.819202)the Research Council of Finland’s Flagship Programme and Doctoral Education Pilot under project Digital Waters(Grant No.359248)funded by the Research Council of Finland's Flagship ProgrammeStrategic Research Council(SRC)through project‘Water&Food’(Grant No.365512).
文摘Endowed with opportunities from both land and ocean,coastal areas attract expanding human populations and economic activities.At the same time,they face growing societal and environmental pressures from both the above river catchments and the bordering sea due to climate change,ecosystem degradation,and expansion of built-up areas.Despite the accumulation of human population,economic activities,and environmental impacts,we lack social-ecological systems analysis on water-related risks to world’s coastal human population.To address this research gap,we analyze the spatial extent of six globally important water stressors to people within the world’s coastal zone(100 km from the coastal line)and classify this zone globally into 12 groups by distance from the coastline and elevation from the mean sea level.Adopting the approaches of the UN Sendai Framework and IPCC,we produce risk maps from the stressor maps by multiplying them with population exposure and vulnerability.For most risks,geographical hotspots are the Chinese coast,Bay of Bengal,Gujarat,and the Island of Java.The analysis reveals fundamental differences between water stressors and related risks,often mixed in scholarly literature.Both manifest specific geographic patterns and latitudinal profiles.Our study highlights the importance of high-resolution spatial analysis of vulnerability,exposure,and risks posed by water related stressors in the world’s coastal zone,in a manner prompted by key policy bodies to promote policy design and shared responsibility for managing stress-prone areas.
基金supported by Shaanxi Provincial Key Research and Development Project(No.2022ZDLSF06-08)Shaanxi Provincial Key Scientific and Technological Innovation Team,China(No.2023-CX-TD-32)+1 种基金the Key Scientific Research Projects of Education Department of Shaanxi Province,China(No.22JY035)the Project of Youth Talent Lift Program of Shaanxi Association for Science and Technology,China(No.20230447).
文摘In the conventional water treatment process,algae have a propensity to breach the filter barriers and potentially seep into the water distribution system,leading to an elevation in taste and odor compounds(T&O compounds).This investigation delved into the seasonal fluctuations of algae penetration and the production of T&O compounds within the treatment units of Reservoir Water Plant 1(W1)and River Water Plant 2(W2).The findings indicated that despite the application of the‘pre-oxidation,coagulation and sedimentation(PCS),sand filtration,and disinfection’process,certain robust-walled filamentous Cyanobacteria,Bacillariophyta species,and small Chlorophyta genera managed to bypass the filters.The leakage of algal cells during autumn at W1 was particularly striking,with a peak of 1,170,000 cells/L.The concurrent assessment of the potential for T&O compound formation revealed an alarming high potential for 2-methylisoborneol(2-MIB)in the water leaving the plants,with concentrations soaring to 197.20 ng/L at W1 in autumn and 54.78 ng/L at W2 in summer.This underscores the significant capacity of residual algal cells to generate T&O compounds.Tracking the retention and penetration dynamics of algal cells across each drinking water treatment stage is crucial for surface water treatment facilities to develop effective operational and management strategies,thereby enhancing the safety and quality of drinking water for the end consumer.
基金supported by the National Natural Science Foundation of China(Nos.42472316,42072286 and 41761144059)the National Key Research and Development Program of China(No.2023YFC3706901)Qinchuangyuan"Scientist+Engineer"Team Development Program of the Shaanxi Provincial Department of Science and Technology(No.2022KXJ-005).
文摘Using unscientific agricultural methods can harm human health by increasing harmful nitrate(NO_(3)−)levels in groundwater,as observed in the Yinchuan Plain.This research utilized hydrochemical data,dual isotopic data,the MixSIAR model,and the uncertainty index(UI90)to detect the potential sources of groundwater NO_(3)−,track NO_(3)−conversion processes,and calculate the apportionment of each groundwater NO_(3)−source in the agricultural lands of the Yinchuan Plain.The results show that soil organic nitrogen accounted for 49.4%,and N-fertilizers contributed 30.4%,making them the two main contributors to NO_(3)-contamination in groundwater.Long-term N-fertilization enhances soil organic nitrogen accumulation,resulting in NO_(3)−leaching into groundwater during irrigation.The highest uncertainty regarding soil organic nitrogen and N-fertilizers may stem from changes in groundwater flow patterns,unbalanced N-fertilization,irrigation,and precipitation.Denitrification is the dominant process,resulting in lower NO_(3)−concentrations in groundwater in most areas.As a result,most groundwater in the Yinchuan Plain is generally safe for human consumption,except the specific areas in Qingtongxia City and Wuzhong City.Flood irrigation can increase the leaching of NO_(3)−into groundwater,and the repeated recharge of groundwater contaminated with high NO_(3)−levels could also be a potential source of NO_(3)−contamination in agricultural areas.This research provides scientific guidance for sustainable groundwater management in the Yinchuan Plain,mitigating the risk of groundwater NO_(3)−pollution.
基金supported by the National Key Research and Development Program of China(No.2022YFC3203703)the National Natural Science Foundation of China(No.52270013).
文摘Although activated carbon filters are thought to be the best way to remove per-and polyfluorinated alkyl substances(PFAS),it is yet unknown how biofilms affect PFAS removal.This study first examined how the removal of PFAS in full-scale drinking water treatment plants(DWTPs)was impacted by biofilm from biological activated carbon(BAC)of varying depths and carbon ages.PFAS desorption from BAC was visible,but at this point,BAC could still remove dissolved organic matter(DOM)efficiently.Studies have demonstrated that the use of activated carbon filters can dramatically lower the content of PFAS in water,with the amount of PFAS reducing as the filter’s depth grows and its use duration increases.Additionally,pore-clogging becomes more noticeable as the biofilm ages,which reduces BAC’s capacity to eliminate PFAS and hinders PFAS desorption.Furthermore,the adsorption process of PFAS may be impeded by the secretion of biofilms,which are composed of proteins and polysaccharides.Based on the analysis above,it can be the adsorption of PFAS by BAC is significantly inhibited by biofilms,according to another research.This provides theoretical direction for improving the removal effectiveness of PFAS in DWTPs.
文摘The most common aspect of water conveyance tunnel construction is the use of horizontal and sub-horizontal exploration drilling of headings of a tunnel to predict geology and groundwater conditions.The instability of boreholes,extreme loss of circulation,and high-head inflow are also common in fractured strata,which often inhibit completion of probe holes and the reliability of coring,packer testing,and grouting tests.Casing,consequently,is a significant enabling technology to stabilize fractured intervals and has a hydraulic isolation under coupled mechanical and hydrogeological disturbances.The review is a synthesis of research and engineering experience on methods of casing to be used in horizontal drilling of fractured rock masses used in the exploration of water conveyance tunnels.The geological and working environment is initially outlined with a focus on fracture-adaptable instability processes and the special goings on of underground drilling,such as the restricted workspace,cuttings difficult to move,and fast movement of the competent and crushed regions.Types of casing systems are then listed,including both standard threaded steel strings and telescopic programs,and more specialized casing system types,including expandable casing,swellable sealing elements,and external casing packers.Special focus is made on the sealing of annulus in horizontal holes,wherein slurry loss,gravity segregation,and non-uniform borehole geometry usually worsen isolation.Lastly,the article suggests adaptive choice of strategy according to real-time drilling reaction,and research priorities,such as tunnel-specific performance measurements,coupled hydro-mechanical modelling,and field trials of sophisticated sealing material and data-driven choice making.
基金Under the auspices of the National Key Research and Development Program of China(No.2024YFC3713102)。
文摘Groundwater level(GWL)is a key indicator used to accurately assess groundwater resources and form the foundation for ef-fective groundwater management.This paper integrates a Gate Recurrent Unit(GRU)model with a Multi-head Self-attention mechan-ism(MSAM-GRU)to simulate GWLs in both confined and unconfined aquifers simultaneously.The model innovatively captures the lag times between GWLs in the unconfined aquifer and precipitation,as well as between GWLs in the confined aquifer and the upper aquifer.We have assessed the effectiveness of the proposed model using a case study in the Beijing Plain,China from January 2005 to December 2020.With the consideration of lag times,the results indicated that the MSAM-GRU model exhibits a maximum 67%and 73%reduction in RMSE compared to the Attention mechanism-GRU(AM-GRU)and GRU model,respectively.MSAM-GRU model exhibited a 31%reduction in RMSE and a 0.12 increase in R^(2) compared to the same model that do not account for lag time.In Region I,the shortest lag time of GWL in the unconfined aquifer was two months,while that in the confined aquifer was three months,indicating a longer delayed response in the confined aquifer.MSAM-GRU model considering lag time,was then applied to simulate the GWLs in the unconfined aquifer under different scenarios and to analyze whether GWL fluctuations affect subway operations.The simulation res-ults showed that under the scenario 1,the GWL in the unconfined aquifer would rise above the depth of subway station floor,threaten-ing the operation of subways.This study can provide reliable technical support for the accurate simulation of GWLs in multi-aquifer systems.
基金supported by the Natural Science Foundation of China(No.52470105)the Young Taishan Scholars Program of Shandong Province(No.358202103017).
文摘The discharge of micro-polluted water from sources such as agricultural runoff,urban stormwater,and treated effluents presents significant challenges to aquatic ecosystems.Constructed wetlands(CWs)have gained recog-nition as an eco-friendly solution for removing pollutants from various wastewater sources and are increasingly applied for micro-polluted water treatment.By reviewing 78 full-scale CW studies from Web of Science,it is summarized that the ranges of ammonium nitrogen(NH4+-N)concentrations in runoff,wastewater treatment plant effluent and polluted river were 0.1–6.6,0.3–12.3,and 0.2–41.1 mg/L,respectively.The ranges of ni-trate nitrogen concentrations were 0.2–14.2,0–5.7,and 0–2.6 mg/L,respectively.Removal efficiencies of CWs for micro-polluted water varied by CW types.The total nitrogen removal efficiencies for subsurface-flow CWs,free-water surface-flow CWs,and hybrid CWs ranged from 27.4%to 66.5%,16.8%to 89.8%,and 19.4%to 88.2%,respectively.The NH4+-N removal efficiencies ranged from 34.2%to 73.6%,38.4%to 89.4%and 13.5%to 94.2%,respectively.Additionally,other factors influencing contaminant removal efficiency such as hydraulic retention time,vegetation types,redox micro-environment and influent water quality were evaluated.Based on these findings,two strategies for improving the purification performance of CWs were proposed:the selection of incorporating electron donor substrates and the optimization of operation parameters.This paper serves as a synthesis of information to guide future research and full-scale CW applications in micro-polluted water treatment.
基金supported by the Iran National Science Foundation(INSF)the University of Birjand under grant number 4034771.
文摘Groundwater modeling remains challenging due to heterogeneity and complexity of aquifer systems,necessitating endeavors to quantify Groundwater Levels(GWL)dynamics to inform policymakers and hydrogeologists.This study introduces a novel Fuzzy Nonlinear Additive Regression(FNAR)model to predict monthly GWL in an unconfined aquifer in eastern Iran,using a 19-year(1998–2017)dataset from 11 piezometric wells.Under three distinct scenarios with progressively increasing input complexity,the study utilized readily available climate data,including Precipitation(Prc),Temperature(Tave),Relative Humidity(RH),and Evapotranspiration(ETo).The dataset was split into training(70%)and validation(30%)subsets.Results showed that among three input scenarios,Scenario 3(Sc3,incorporating all four variables)achieved the best predictive performance,with RMSE ranging from 0.305 m to 0.768 m,MAE from 0.203 m to 0.522 m,NSE from 0.661 to 0.980,and PBIAS from 0.771%to 0.981%,indicating low bias and high reliability.However,Sc2(excluding ETo)with RMSE ranging from 0.4226 m to 0.9909 m,MAE from 0.3418 m to 0.8173 m,NSE from 0.2831 to 0.9674,and PBIAS from−0.598%to 0.968%across different months offers practical advantages in data-scarce settings.The FNAR model outperforms conventional Fuzzy Least Squares Regression(FLSR)and holds promise for GWL forecasting in data-scarce regions where physical or numerical models are impractical.Future research should focus on integrating FNAR with deep learning algorithms and real-time data assimilation expanding applications across diverse hydrogeological settings.
基金supported by the National Key Research and Development Program of China(Grants No.2024YFF0810500 and 2022YFD1900802)the National Natural Scientific Foundations of China(Grants No.41991232,42301016 and 42571034)the Hainan Provincial Natural Science Foundation of China(Grant No.424QN354).
文摘Accurate water budget closure is critical for sustainable water resource management facing increased pressures from climate change and human activities.Although error reduction methods for individual water balance components have advanced,persistent biases remain due to the independent development of datasets,impacting basin scale water budget balance.In this research,we analyzed the mathematical origin of the bias between water budget components and developed a new basin-scale water balance calibration method that redistributes errors across components while enforcing water balance constraints.Validation confirms systematic improvements,with reduced RMSE(Precipitation:-2.29 mm/month;ET:-1.34 mm/month)and increased R2 against in situ observations.Applied to the Jinghe River Basin(2000−2019),the calibrated data reveal declining precipitation(-1.70 mm/year)and evapotranspiration(-1.84 mm/year)alongside slightly increasing runoff(0.20 mm/year in basin depth),signaling a drying trend.Land cover changes—marked by cropland loss(-3,497 km^(2))and forest(+720 km^(2))and grassland(+2,776 km^(2))expansion—reflect improved water consumption requirements by ecosystem,raising concerns for water retention and ecosystem stability.The method is particularly effective for ungauged basins with sparse ground data and underscores the need for integrated land-water management to enhance long-term resilience.
基金supported by the National Natural Science Foundation of China(W2412135)the Youth Innovation Promotion Association of the Chinese Academy of Sciences.
文摘As a major source of freshwater in Central Asia,Tajikistan is endowed with abundant glaciers and water resources.However,the country faces multiple challenges,including accelerated glacier retreat,complex inter-government water resource management,and inefficient water use.Existing research has predominantly focused on individual hydrological processes,such as glacier retreat,snow cover change,or transboundary water issues,but it has yet to fully capture the overall complexity of water system.Tajikistan’s water system functions as an integrated whole from mountain runoff to downstream supply,but a comprehensive study of its water resource has yet to be conducted.To address this research gap,this study systematically examined the status,challenges,and sustainable management strategies of Tajikistan’s water resources based on a literature review,remote sensing data analysis,and case studies.Despite Tajikistan’s relative abundance of water resources,global warming is accelerating glacier melting and altering the hydrological cycles,which have resulted in unstable runoff patterns and heightened risks of extreme events.In Tajikistan,outdated infrastructure and poor management are primary causes of low water-use efficiency in the agricultural sector,which accounts for 85.00%of the total water withdrawals.At the governance level,Tajikistan faces challenges in balancing the water-energy-food nexus and transboundary water resource issues.To address these issues,this study proposes core paths for Tajikistan to achieve sustainable water resource management,such as accelerating technological innovation,promoting water-saving agricultural technologies,improving water resource utilization efficiency,and establishing a community participation-based comprehensive management framework.Additionally,strengthening cross-border cooperation and improving real-time monitoring systems have been identified as critical steps to advance sustainable water resource utilization and evidence-based decision-making in Tajikistan and across Central Asia.
