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Groundwater resources are vital to ecosystems and livelihoods. Excessive groundwater withdrawals can cause groundwater levels to decline1-10, resulting in seawater intrusion11, land subsidence12,13, streamflow depletion14-16 and wells running dry17. However, the global pace and prevalence of local groundwater declines are poorly constrained, because in situ groundwater levels have not been synthesized at the global scale. Here we analyse in situ groundwater-level trends for 170,000 monitoring wells and 1,693 aquifer systems in countries that encompass approximately 75% of global groundwater withdrawals18. We show that rapid groundwater-level declines (>0.5 m year-1) are widespread in the twenty-first century, especially in dry regions with extensive croplands. Critically, we also show that groundwater-level declines have accelerated over the past four decades in 30% of the worlds regional aquifers. This widespread acceleration in groundwater-level deepening highlights an urgent need for more effective measures to address groundwater depletion. Our analysis also reveals specific cases in which depletion trends have reversed following policy changes, managed aquifer recharge and surface-water diversions, demonstrating the potential for depleted aquifer systems to recover.

Taxes on sugar-sweetened beverages (SSBs), or drinks with added sugars, show promise in decreasing purchases and consumption of SSBs. Some have called for coupling such taxes with improvements in access to safe drinking water as a strategy for reducing inequities in SSB intake, yet no studies have examined such an approach. Drink Tap is a San Francisco-based program in which public tap water stations were installed in parks and public spaces (winter 2017) and promotional efforts (fall and winter 2018) encouraged water intake. At the same time, San Francisco and surrounding communities were also implementing SSB taxes. We conducted a quasi-experimental study to examine whether water access and promotion combined with SSB taxes affected beverage intake habits more than SSB taxes alone. We conducted 1-hour observations (N = 960) at 10 intervention parks (Drink Tap plus SSB taxes) and 20 comparison parks (SSB taxes only) in San Francisco Bay Area cities before (July-September 2016) and after (June-August 2019) implementation of Drink Tap. We found significant adjusted percentage increases in drinking water among visitors to intervention parks, compared with comparison parks: water from park water sources (+80%, P < .001) and water from reusable bottles (+40%, P = .02). We found no significant reductions in visitors observed drinking bottled water, juices, or SSBs. The Drink Tap intervention led to increases in water intake from park sources and reusable bottles across parks that surpassed increases achieved through SSB taxes alone. Jurisdictions should consider coupling tap water access and promotion with policies for reducing intake of SSBs.

BackgroundAccess to water and sanitation is a basic human right; however, in many parts of the world, communities experience water, sanitation, and hygiene (WaSH) insecurity. While WaSH insecurity is prevalent in many low and middle-income countries, it is also a problem in high-income countries, like the United States, as is evident in vulnerable populations, including people experiencing homelessness. Limited knowledge exists about the coping strategies unhoused people use to access WaSH services. This study, therefore, examines WaSH access among unhoused communities in Los Angeles, California, a city with the second-highest count of unhoused people across the nation.MethodsWe conducted a cross-sectional study using a snowball sampling technique with 263 unhoused people living in Skid Row, Los Angeles. We calculated frequencies and used multivariable models to describe (1) how unhoused communities cope and gain access to WaSH services in different places, and (2) what individual-level factors contribute to unhoused people's ability to access WaSH services.ResultsOur findings reveal that access to WaSH services for unhoused communities in Los Angeles is most difficult at night. Reduced access to overnight sanitation resulted in 19% of the sample population using buckets inside their tents and 28% openly defecating in public spaces. Bottled water and public taps are the primary drinking water source, but 6% of the sample reported obtaining water from fire hydrants, and 50% of the population stores water for night use. Unhoused people also had limited access to water and soap for hand hygiene throughout the day, with 17% of the sample relying on hand sanitizer to clean their hands. Shower and laundry access were among the most limited services available, and reduced people's ability to maintain body hygiene practices and limited employment opportunities. Our regression models suggest that WaSH access is not homogenous among the unhoused. Community differences exist; the odds of having difficulty accessing sanitation services is two times greater for those living outside of Skid Row (Adj OR: 2.52; 95% CI: 1.08-6.37) and three times greater for people who have been unhoused for more than six years compared to people who have been unhoused for less than a year (Adj OR: 3.26; 95% CI: 1.36-8.07).ConclusionOverall, this study suggests a need for more permanent, 24-h access to WaSH services for unhoused communities living in Skid Row, including toilets, drinking water, water and soap for hand hygiene, showers, and laundry services.

Forest restoration through mechanical thinning, prescribed burning, and other management actions is vital to improving forest resilience to fire and drought across the Western United States, and yields benefits that can be monetized, including improvements in water supply and hydropower. Using California's Sierra Nevada as a study area, we assess the water and energy benefits of forest-restoration projects. By using a scalable top-down approach to track annual evapotranspiration following forest disturbance, coupled with hydropower simulations that include energy-price information, and marginal prices for water sales, we project the potential economic benefits of hydropower and water sales accruing to water-rights holders. The results found that water-related benefits from strategically planned fuels-reduction treatments now being carried out can be sufficient to offset costs of management actions aimed at forest restoration, especially in the face of climate change. Our findings justified investments in restoring forests and reinforce the central role of water and hydropower providers in partnerships for management of source-water watersheds. Results also highlighted the importance of accurate, scalable data and tools from the hydrology and water-resources community.

Multi-objective optimization of water distribution networks (WDNs) is crucial for achieving a balance between cost, equity, and reliability. The present study conducts a comparative analysis, evaluating the effectiveness of four multi-objective optimization algorithms implemented within the EPANET framework for the optimal design of three distinct WDNs taken from the literature. The networks were optimized considering three objectives: maximizing network resilience, and uniformity coefficient (CU, a measure of uniformity), alongside minimizing the cost of the network. Further, multi-criteria decision-making (MCDM) analysis is carried out, encompassing various MCDM techniques and weighting methods, to explore the sensitivity of solution rankings. In Network 1, non-dominated sorting genetic algorithm 2 (NSGA-II) produced suboptimal solutions with CU and In values below 0.4, while caRamel, multi-objective particle swarm optimization based on crowding distance (MOPSO-CD), and multi-objective evolutionary algorithm with decomposition (MOEA/D) showcased increasing CU and In values towards 1, paralleled by a rise in network cost. The performance of NSGA-II in Network 3 was unsatisfactory (CU < 0.32), while the other algorithms demonstrated satisfactory values (>0.98) for reliability and (>0.5) for CU. The findings offer valuable insights into cost-effective strategies for achieving equity in water supply without substantial impact on overall network cost. The findings of the study also underscore the sensitivity of ranking outcomes in MCDM analysis to the choice of technique and weighting method. HIGHLIGHTS A multi-objective optimization model is developed for the design of an intermittent water supply system.; The equity in water supply and network resilience along with the cost for the optimal design is considered.; A comparative analysis of various multi-objective optimization algorithms for the design of WDNs is made.; Ranking of optimal solutions is made.; The sensitivity of the ranking by different MCDM techniques is explored.;

Research has shown that food insecurity in households and communities are increasing globally. More people are reported to now having difficulty in accessing safe and quality foods. This study assessed household food and water access as predictors of food security among rural households. This is a cross sectional community survey which used validated tools to collect data among 201 households representing a total population of 1284 in Langai district. Levels of household food and water access were determined; and factors associated with food security were assessed using chi-square. Predictors of food security was assessed using multivariable logistic regression. P < 0,05 was adjudged significant. About 90 % of households own a farm; with almost two-thirds (62,2 %) of households acquiring their food from both self-production and market; and 73,6 % engaging in household agriculture. The majority (82,1 %) of the households sourced their water from boreholes and pipe-borne sources. Significant predictors of food security were lower expenditure on food (AOR: 2,19 [95 % CI: 1,5-4,61]; P = 0,038); not engaged in household agriculture (AOR: 2,88 [95 % CI: 1,09-7,59]; P = 0,032); had access to pipe borne/borehole water (AOR: 2,76 [95 % CI: 1,15-6,44]; P = 0,023) and experienced little or no adverse coping behaviour (AOR: 6,07 [95 % CI: 1,74-21,23]; P = 0,005). Time did not influence food acquisition in the majority of the households. As reported and showcased in this study, the relationship between food security and rural household development is directly proportional in many local communities of a developing country. Efforts should be garnered towards rural household empowerment through improvement in livelihood and security to have sustainable foods and water.

Abstract This study proposes a novel robust optimization approach for an integrated water supply system, wherein the decision-makers attempt to improve failure safety of system under various uncertainty strategies. To cope with uncertainty, the ellipsoid uncertainty set is assumed to evaluate the best feasible solution in the direction of water supply under various strategies. We assessed the case of Hamoun watershed, a water-stressed watershed in southeastern of Iran, to evaluate the developed robust optimization model. In the following, the comparative feasibility under uncertainty levels is conducted to analyze the impacts of simulation strategies on the status of robust model. Based on the final results, the reliability of the model's objective functions experienced an increasing trend ( $$58.3\%$$ 58.3 % ), and the objective function values under the uncertainty strategies is greatly improved. The findings of the analysis show that the robust strategies in response to the failure safety achieve outstanding optimal objectives under uncertainty.

The study objective is to analyze the water expenditure of 4315 rural households in the Karst region of China. The empirical results have been analyzed by using the extended linear expenditure system model. The study has been based on water expenditure, which provides a feasible differential water pricing strategy in the karst region of China. The result shows that (1) the coefficient for water expenditure has been examined as low. The coefficient of water expenditure in the Karst region ranges from 0.534 to 1.025%, the average value is 0.723%, and the modified coefficient ranges from 0.814 to 1.508%, with an average value of 1.070%. (2) The marginal consumption propensity of rural residents in the Karst region is 0.2%, and the marginal consumption propensity in each province ranges from 0.1 to 1%. (3) The per capita basic water demand has 3 m3. In this scenario, the study recommended that basic water prices range from CNY 2.091 to CNY 3.468 per cubic meter. If the water consumption exceeds basic demand (3 m3 per month), then the bearing water price shall not be lower than CNY 2.091 to CNY 3.468 per cubic meter and not higher than CNY 7.122 per cubic meter. HIGHLIGHTS Analyzed the water expenditure of 4,315 rural households in the Karst region of China.; The basic water prices range from CNY 2.091 to CNY 3.468 per cubic meter.; The water price reform in rural China should be subsidies and flexible.; Increasing financial subsidies for low-income households and charging discount fees to households with idle water equipment.; Water pricing mechanism should be flexible for everyone.;

Exploring the drivers of changes in ecosystem services is crucial to maintain ecosystem functionality, especially in the diverse Central Citarum watershed. This study utilises the integrated valuation of ecosystem service and trade-offs (InVEST) model and multiscale geographically weighted regression (MGWR) model to examine ecosystem services patterns from 2006 to 2018. The InVEST is a hydrological model to calculate water availability and evaluate benefits provided by nature through simulating alterations in the amount of water yields driven by land use/cover changes. Economic, topographic, climate, and vegetation factors are considered, with an emphasis on their essential components. The presence of a geographical link between dependent and explanatory variables was investigated using a multiscale geographic weighted regression model. The MGWR model is employed to analyse spatial impacts. The integration of both models simplified the process and enhanced its understanding. The findings reveal the following patterns: 1) decreasing land cover and increasing ecosystem services demand in the watershed, along with a decline in water yield, e.g. certain sub-districts encounter water scarcity, while others have abundant water resources; 2) the impact of natural factors on water yield shifts along vegetation > climate > topography (2006) changes to climate > vegetation > topography (2018).

The Proton Exchange Membrane Fuel Cell - Mechanical Heat Pump - Combined Heat and Power (PEMFC-MHP-CHP) system is a reliable energy supply solution, which can operate independently of the grid during emergencies or be used for peak shaving and load leveling in renewable energy networks. This paper proposes two system structures, namely the separated and integrated systems and establishes MATLAB/Simulink models. Then, a sensitivity analysis is conducted, examining system design and operation. The results show that the separated system can satisfy basic heating and electricity demands without an external power supply at −14.5 °C. Increasing the number of cells by 20, reducing one room's heat load (36 m2), or increasing the current density by 0.1 A/cm2 results in reductions in compressor power consumption ranging from 1.76 % to 2.91 %, 7.42 %–10.57 %, and 6.52 %–16.88 %, respectively. On the other hand, the integrated system has higher power consumption but can operate smoothly at lower temperatures than the separated system. It is suitable for integration with auxiliary power devices in low-temperature environments. The PEMFC's heat output minimally affects system efficiency. Reducing the number of rooms improves system performance, with each reduction of one room decreasing compressor power consumption by 5.43 %–8.55 %. Meanwhile, two design options are identified based on the power supply and hot water demands. Further research and development can enhance the efficiency and performance of these systems, promoting their wider use in the future. • Established MATLAB/Simulink models for the PEMFC-MHP-CHP system. • Demonstrated better performance and stable heating capacity compared to conventional CHP systems. • Provided insights into advantages and limitations of separated and integrated systems. • Conducted a thorough performance analysis under load fluctuations for energy supply and peak shaving. • Proposed system design and operational options based on sensitivity analysis. [ABSTRACT FROM AUTHOR]

Hebi is located in the northern part of China's Henan Province and is a typical receiving area for China's South-to-North Water Diversion Project. The assessment of habitat quality and water yield over a long time series is important for evaluating the stability of ecosystem services in Hebi and other receiving areas and for maintaining ecological security and promoting sustainable development. This paper aims to evaluate and dynamically analyse habitat quality and water yield in Hebi, and analyses the characteristics of changes in spatial and temporal patterns of land cover types, habitat quality and water yield in Hebi over the past 20 years, using 2000, 2005, 2010, 2015 and 2020 as horizontal years. The results indicate that: (1) During the study period, the overall land use type in Hebi City has been constantly changing, with the most significant conversion from arable land to other land types; combined with its landscape pattern index, Hebi City has a general characteristic of significant landscape fragmentation and complexity in land use. (2) Habitat quality in Hebi shows an overall trend towards better development, with water availability decreasing and then increasing; the zoning of ecosystem services in Hebi is divided into three classes: superior, good and general, with the area covered by the superior and general classes expanding year by year. (3) Correlation analysis by SPSS software shows that the correlation between habitat quality and landscape pattern index is greater than the correlation between habitat quality and climate change. Additionally, the correlation between water availability and climate change is greater than the correlation between water availability and landscape pattern index. [ABSTRACT FROM AUTHOR]

Water is our most valuable and precious resource, yet it is only available in a limited amount. Sustainable use of water can therefore only operate in a circular way; nonetheless, still today depletion of water resources proceeds at an accelerated pace. Here, we quantitatively assess the water circular economy and the status of water management across 132 countries distributed over six continents by introducing the water circular economy index, WCEI, based on the three pillars of water circular economy, i.e., decreasing, optimising, and retaining. This index relies on eight indicators such as water stress, tap water price, water use efficiency, the degree of water resource management, proportion of safely treated wastewater, population with access to safe drinking water, drinking water quality, and surface water changes in hydrological basins. It allows ranking 132 countries, and most importantly to identify criticalities and bottlenecks in the sustainable use of water resources across the six continents, pointing at possible directions and actions towards a fully circular economy of water. [ABSTRACT FROM AUTHOR]

Background and Aims Mediterranean ecosystems have a high vascular plant species richness (SR) relative to their surface area. This SR, representing the balance between speciation and extinction, has been attributed to multiple mechanisms that result in both high rates of speciation and/or low rates of extinction. An abiding question is, however, what is special about Mediterranean ecosystems that enables this high SR? Apart from the long-term climatic stability of the region, SR has also been related to resource availability, the many individuals hypothesis, resource spatial heterogeneity, temporal heterogeneity and biotic feedbacks. Methods Spatial patterns of species richness were related to climatic, edaphic and biotic variables and to spatial variability within the Greater Cape Floristic Region (GCFR) of South Africa. Boosted regression tree models were used to explore the strength of relationships between SR and environmental predictors related to each hypothesized mechanism. Key Results Water availability (i.e. precipitation) was a stronger predictor of SR than potential evapotranspiration or temperature. Scarcity of nutrients was also related to SR. There was no indication that SR was related to the density of individuals and only temporal heterogeneity induced by fire was related to SR. Spatial heterogeneities of climatic, edaphic and biotic variables were strongly associated with SR. Biotic interactions remain difficult to assess, although we have some evidence for a putative role in regulating SR. Conclusions While the lack of ecosystem-resetting disturbances (e.g. glaciation) is undoubtedly a key requirement for high species accumulation, predictably, no one explanation holds the key to understanding SR. In the GCFR high SR is the product of a combination of adequate water, nutrient scarcity, spatial and temporal heterogeneity, and possibly biotic feedbacks. [ABSTRACT FROM AUTHOR]

In this study, the thermal comfort and energy consumption of two different terminal units when combined with three different water supply temperatures were studied. Results showed that convection–radiation combined cooling terminals can increase the water supply temperature under the same thermal comfort level compared with convection cooling terminals. When the water supply temperature was fixed at 11 °C, the energy consumption of convection–radiation combined cooling terminals was 9.1 % lower than that of convection cooling terminals. The higher the water supply temperature, the lower the energy consumption under convection–radiation combined cooling terminals. Furthermore, the energy consumption rates at a water supply temperature of 15 °C were 18.2 % and 8.8 % lower than those at 7 °C and 11 °C, respectively. Meanwhile, the comfort and system operation efficiency were optimal when the water supply temperature was 15 °C, and the energy consumption was lower when combined with the cooling of the dual terminals. [ABSTRACT FROM AUTHOR]

Neighbourhood interactions drive tree growth and forest ecosystem functioning. The strength of interactions depends on the climate. However, it remains unclear how plant–plant interactions are modified by environmental conditions operating both spatially and temporally, which is crucial for predicting forest dynamics under climate change and for effective forest management.In this study, we used annual growth data for 4139 stems from 2010 to 2021 across 50 permanent forest plots located at six sites in eastern China. We quantified the effect of neighbourhood crowding on the annual basal area increment. We explored how interactions among neighbouring trees vary with water availability and temperature gradients in the spatial (across sites) and temporal (across time within sites) dimensions.Our findings revealed a negative impact of neighbourhood crowding on stem basal area growth, which is size‐ and trait‐dependent at some sites. The negative effects of light competition tended to be more intense at warmer sites, supporting the stress‐gradient hypothesis (SGH) in a spatial dimension. However, the patterns of crowding effects along interannual climate anomalies are inconsistent across sites, making it difficult to predict crowding effects under the SGH framework in a temporal dimension.Synthesis: Our study demonstrated that tree interactions depend on the climate context. The climate dependence of interactions may be inconsistent between the spatial and temporal dimensions. Light competition across sites supported the SGH in the spatial dimension but not in the temporal dimension. These results further highlight the complexity of biotic interactions and the need for caution when extrapolating findings from the spatial to the temporal dimension. [ABSTRACT FROM AUTHOR]

Deserts are predicted to be one of the ecosystems most vulnerable to global climate change, with dramatic fluctuations of temperature and water, even over the span of a single day. These previous disturbances could influence the response of the soil microbiome and its functions to subsequent disturbances, which is known as legacy effect. However, how legacy effects shape the response of soil microbiome and its functions to environmental fluctuations (e.g. temperature and water availability) in desert ecosystems remains to be investigated.Here, we firstly exposed desert soils to drought, freezing or their combination, and then followed by a second disturbance, resulting in a temporally full factorial treatment.We found that environmental change legacies affected the response of soil multifunctionality, microbial abundance and richness to second drought and freezing, except for eukaryotic richness. Initial disturbances caused legacy effects on microbial composition and weakened their responses to later disturbances, and these effects were stronger for prokaryotes than eukaryotes. The attenuated response to later disturbances is largely due to that almost half of the taxa affected by the earlier disturbances were also affected by the second disturbances. The phylogenetic depth of these responses varied minimally among the types of disturbances but were more conserved for negative responses, indicating a result of historical adaptation. Moreover, the altered community composition was associated with functional changes in the disturbed soils.These findings will improve our understanding of the mechanisms underlying the legacy impacts of multiple environmental disturbances on desert microbial communities and strengthen our ability to develop management strategies for protection prior to disturbance events. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Water vapour is a critical component of the hydrological cycle and plays a key role in climate systems and water resources on the Tibetan Plateau (TP). However, the effect of water vapour on extreme precipitation during the snow season over the TP, where snow cover is widespread, has not been determined. In this study, we investigated the water vapour contributions from extreme precipitation events during the snow season from 1980 to 2017 in four subregions of the TP using the flexible particle dispersion method. We divided the TP into four regions: the northeastern TP (NETP), northwestern TP (NWTP), southeastern TP (SETP) and southwestern TP (SWTP). The water vapour contributions from extreme precipitation among the four subregions were clearly different. The most important water vapour area that contributed the most water vapour to extreme precipitation over the NETP was from local contributions; nevertheless, Central Asia contributed the most water vapour to the NWTP. Water vapour from the Arabian Sea and Bay of Bengal (ASBB) dominantly controlled extreme precipitation in the SETP at a ratio of 45% and in the SWTP at a ratio of 72.9%. The water vapour contribution from the ASBB was significantly correlated with the extreme precipitation occurring in the TP subregions during the snow season in comparison to that of non‐extreme precipitation. These results could improve the understanding of water vapour cycle differences across the interior TP; additionally, our study provides a theoretical reference for the relationship between the snow distribution and water vapour sources in the TP. [ABSTRACT FROM AUTHOR]

Anthropogenic revegetation is an effective way to control soil erosion and restore degraded ecosystems in China's northwest drylands (NWD). However, excessive vegetation cover expansion has long been known to increase evapotranspiration, leading to reduced local water availability, which can in turn threaten the health and services of restored ecosystems. Determining the optimal vegetation coverage (OVC) is critical for balancing the trade-off between plant growth and water consumption in water-stressed areas, yet quantitative assessments over the entire NWD are still lacking. In this study, a modified Biome BioGeochemical Cycles (Biome-BGC) model was used to simulate the long-term (1961–2020) dynamics of actual evapotranspiration (ETa), net primary productivity (NPP), and leaf area index (LAI) for the dominant non-native tree (R. pseudoacacia and P. sylvestris) and shrub (C. korshinkii and H. rhamnoides) species at 246 meteorological sites over NWD. The modified model incorporated the Richards equation to simulate transient unsaturated water flow in a multilayer soil module, and both soil and eco-physiological parameters required by the model were validated using field-observed ETa data for each species. Spatial distributions of OVC (given by the mean maximum LAI, LAImax) for the dominant species were determined within three hydrogeomorphic sub-areas (i.e., the loess hilly-gully sub-area, the windy and sandy sub-area, and the desert sub-area). The modified Biome-BGC model performed well in terms of simulating ETa dynamics for the four plant species. Spatial distributions of mean ETa, NPP, and LAImax generally exhibited patterns similar to mean annual precipitation (MAP). In the loess hilly-gully sub-area (MAP: 210 to 710 mm), the OVC respectively ranged from 1.7 to 2.9 and 0.8 to 2.9 for R. pseudoacacia and H. rhamnoides. In the windy and sandy sub-area (MAP: 135 to 500 mm), the OVC ranged from 0.3 to 3.3, 0.5 to 2.6 and 0.6 to 2.1 for P. sylvestris, C. korshinkii and H. rhamnoides, respectively. In the desert sub-area (MAP: 90 to 500 mm), the OVC ranged from 0.4 to 1.7 for H. rhamnoides. Positive differences between observed and simulated plant coverage were found over 51% of the forest- and shrub-covered area, especially in the loess hilly-gully sub-area, suggesting possible widespread overplanting in those areas. This study provides critical revegetation thresholds for dominant tree and shrub species to guide future revegetation activities. Further revegetation in areas with overplanting should be undertaken with caution, and restored ecosystems that exceed the OVC should be managed (e.g., thinning) to maintain a sustainable ecohydrological environment in the drylands. [ABSTRACT FROM AUTHOR]

From 1956 to 2016, Hai River Basin suffered the most severe surface water resource attenuation among the 10 first-class river basins in China. Based on the surface water circulation process, and evolving characteristics of precipitation and underlying surface in Hai River Basin, this study attributed the causes of surface water resource attenuation to six primary impact factors, analyzed each factor's quantitative contribution, and revealed four patterns of surface water resource attenuation in Hai River Basin. The pattern of the dominant factor: comparing the 1980–2000 period with the 1956–1979 period, the variation of precipitation is the dominant factor of which contribution is 7 billion m3, accounting for 59% of total 11.7 billion m3; comparing the 2001–2016 period with the 1956–1979 period, the increasing of vegetation cover in mountainous area is the dominant factor of which contribution is 2.78 billion m3, accounting for 51% of total 4.9 billion m3. The pattern of spatial distributions: comparing the 2001–2016 period with the 1956–1979 period, mountainous areas were more affected by increasing vegetation cover which for example contributed 42% in Luan River Basin mountainous; the plains were more impacted by farmland ridge interception which for example contributed 51% in Beisi River Basin plains. The pattern of attenuation trend: comparing the 2001–2016 period with the 1980–2000 period, surface water resources in mountainous areas continued to decline, owing to the increasing water consumption of large-scale vegetation restoration, while the influence of the underlying surface changes on surface water resources in plains areas tended to remain stable. The pattern of reversible change: among factors led to surface water resource attenuation, the human activity, including vegetation cover increase, farmland ridge interception, and urbanization expansion, contributed 36% of the attenuation, which resulted in the variation of precipitation-runoff relation. This study improved the traditional attribution classification model of climate change and human activity and analyzed the causes and contributions of water resource attenuation in Hai River Basin based on the water circulation process, which can provide scientific support for the development of water resource management in the basin. [ABSTRACT FROM AUTHOR]

This study explored how the water balance components of the Middle Tapi Basin (MTB) might alter between 2010 and 2100 as an outcome of climate change. We used an approach were Statistically downscaled future predicted data for temperature and rainfall for five different Global circulation models were employed under two Representative Concentration Pathways (RCP 4.5 and RCP 8.5). The baseline and future scenarios' monthly analyses of multiple water balance indicators also showed that RCP 4.5 and RCP 8.5 will see an increase in maximum temperature of 5.2% and 9.5%, respectively, by the end of the century. The baseline period contribution from monsoonal rainfall and streamflow was also 89.3% and 90.6%, but in future scenarios, the figures are likely to reduce to 75.2% and 57.8% for RCP 4.5 and 70.8% and 54.7% for RCP 8.5. While the average inflow estimates at the Ukai dam tend to rise by 19.2% and 46.8% till the distant future scenario for RCP 4.5 and RCP 8.5, respectively. In future scenarios, the percentage of groundwater flow and surface runoff contributions will be lesser due to the higher evapotranspiration rate and revaporisation of water to the root zone. Even though the monsoonal rainfall tends to reduce, the flow duration curves for the future scenarios exhibited a consistent increase in water availability compared to their respective historical counterparts, possibly due to more frequent and severe rainfall events. [ABSTRACT FROM AUTHOR]

To examine the driver of groundwater depletion, this paper estimates a dynamic panel regression model using district-level secondary data from 1995 to 2017. Results show that the number of rainwater-harvesting structures, annual average rainfall, forest cover and net sown area improve groundwater levels. Tube well irrigation and rice cultivation can adversely affect groundwater levels. The positive relationship between surface water and improved groundwater level is consistent in all the estimated models. Hence, efficient use and management of surface and groundwater are crucial for the long-term sustainability of water resources. [ABSTRACT FROM AUTHOR]

This study uses the Just–Pope approach to investigate the effects of seasonal weather variables and extremes on the mean yield and yield variability of rice, bajra, chickpea, groundnut and sugarcane in India during the period 1990–2015. Results reveal that changes in rainfall and evapotranspiration across seasons largely affect mean yields for most crops, including bajra, chickpea and groundnut. However, high summer rainfall and low monsoon evapotranspiration extremes reduce groundnut and chickpea yield variability. Considering the importance of water availability to crop yields, this study suggests improving irrigation and water reallocation and management to reduce the severity of seasonal climate effects. [ABSTRACT FROM AUTHOR]

Emerging climate-development processes jeopardize water supply, especially in the Global South. In the Vietnamese Mekong Delta, disrupted water flows driven by climate change and hydropower development have caused water scarcity, threatening agricultural systems in both upstream and coastal areas. Based on insights from desk reviews, stakeholder workshops and interviews with local informants, this paper argues that while grey (engineered) solutions take precedence in addressing water scarcity, securing water sustainability (water retention) for agricultural resilience demands integrated 'grey–green' (engineered-nature-based) solutions. This paper suggests demands for translating this approach into the water governance framework for the delta's agricultural development. [ABSTRACT FROM AUTHOR]

In South Africa, approximately 98% of the predicted total surface water resources are already being used up. Consequently, the National Water Resource Strategy considers groundwater to be important for the future planning and management of water resources. In this case, quantifying groundwater budgets is a prerequisite because they provide a means for evaluating the availability and sustainability of a water supply. This study estimated the regional groundwater budgets for the Inkomati‐Usuthu Water Management Area (Usuthu, Komati, Sabie‐Sand, and Crocodile) using the classical hydrological continuity equation. The equation was used to describe prevailing feedback loops between groundwater draft, recharge, baseflow, and storage change. The results were coarser scale estimates which, beforehand, were derived from the 2006 study. In the years to follow, groundwater reliance intensified and there was also the historic 2015/2016 drought. This inevitably led to an increased draft while the rest of the components of the groundwater budgets experienced decreases. Both Crocodile and Sabie‐Sand experienced groundwater storage depletion which led to reduced baseflow and groundwater availability, while groundwater recharge contrarily increased due to capture. Conversely, the other two catchments experienced relatively lower drafts with correspondingly higher groundwater availability and recharge while storage change was positive. The results highlighted the need for adaptive water management whose effectiveness relies on predictive studies. Consequently, future models should be developed to capture the spatial and temporal dynamism of the natural groundwater budget due to climate change, water demands, and population growth predictions. Article impact statement: Updated quantitative estimates of the regional groundwater budget following severe draughts and increased groundwater reliance. [ABSTRACT FROM AUTHOR]

Hydraulic fracturing (HF) events consume high volumes of water over a short time. When groundwater is the source, the additional pumping by rig/frack supply wells (RFSWs) may impose costs on owners of other sector wells (OSWs) by lowering the hydraulic head. The Carrizo–Wilcox aquifer in south Texas is the main source of water for HF of the Eagle Ford Shale (EFS) Play. The objectives are to assess the impacts of groundwater pumping for HF supply on: (1) hydraulic heads in OSWs located nearby an RFSW and (2) volumetric fluxes between layers of the regional aquifer system compared to a baseline model without the effect of RFSW pumping. The study area spans the footprint of the EFS Play in Texas and extends from 2011 to 2020. The pumping schedules of 2500 RFSWs were estimated from reported pumped water volumes to supply 22,500 HF events. Median annual drawdowns in OSWs ranged from 0.2 to 6.6 m, whereas 95th percentile annual drawdowns exceeded 20 m. The magnitudes of drawdown increased from 2011 to 2020. Of the four layers that comprise the Carrizo–Wilcox aquifer, the upper Wilcox was the most intensively pumped for HF supply. During the peak HF year of 2014, the net flux to the upper Wilcox was 292 Mm3 compared to the baseline net flux for the same year of 278 Mm3—a relative gain of 14 Mm3. Pumping for HF supply has the potential to negatively impact nearby OSWs by capturing water from adjacent aquifer layers. [ABSTRACT FROM AUTHOR]

Objectives: Reports of unsafe school drinking water in the United States highlight the importance of ensuring school water is safe for consumption. Our objectives were to describe (1) results from our recent school drinking water sampling of 5 common contaminants, (2) school-level factors associated with exceedances of various water quality standards, and (3) recommendations. Methods: We collected and analyzed drinking water samples from at least 3 sources in 83 schools from a representative sample of California public schools from 2017 through 2022. We used multivariate logistic regression to examine school-level factors associated with lead in drinking water exceedances at the American Academy of Pediatrics (AAP) recommendation level (1 part per billion [ppb]) and state action-level exceedances of other contaminants (lead, copper, arsenic, nitrate, and hexavalent chromium). Results: No schools had state action-level violations for arsenic or nitrate; however, 4% had ≥1 tap that exceeded either the proposed 10 ppb action level for hexavalent chromium or the 1300 ppb action level for copper. Of first-draw lead samples, 4% of schools had ≥1 tap that exceeded the California action level of 15 ppb, 18% exceeded the US Food and Drug Administration (FDA) bottled water standard of 5 ppb, and 75% exceeded the AAP 1 ppb recommendation. After turning on the tap and flushing water for 45 seconds, 2%, 10%, and 33% of schools exceeded the same standards, respectively. We found no significant differences in demographic characteristics between schools with and without FDA or AAP exceedances. Conclusions: Enforcing stricter lead action levels (<5 ppb) will markedly increase remediation costs. Continued sampling, testing, and remediation efforts are necessary to ensure drinking water meets safety standards in US schools. [ABSTRACT FROM AUTHOR]

Body water balance is determined by fundamental homeostatic mechanisms that maintain stable volume, osmolality and the composition of extracellular and intracellular fluids. Water balance is maintained by multiple mechanisms that continuously match water losses through urine, the skin, the gastrointestinal tract and respiration with water gains achieved through drinking, eating and metabolic water production. Hydration status is determined by the state of the water balance. Underhydration occurs when a decrease in body water availability, due to high losses or low gains, stimulates adaptive responses within the water balance network that are aimed at decreasing losses and increasing gains. This stimulation is also accompanied by cardiovascular adjustments. Epidemiological and experimental studies have linked markers of low fluid intake and underhydration — such as increased plasma concentration of vasopressin and sodium, as well as elevated urine osmolality — with an increased risk of new-onset chronic diseases, accelerated aging and premature mortality, suggesting that persistent activation of adaptive responses may be detrimental to long-term health outcomes. The causative nature of these associations is currently being tested in interventional trials. Understanding of the physiological responses to underhydration may help to identify possible mechanisms that underlie potential adverse, long-term effects of underhydration and inform future research to develop preventative and treatment approaches to the optimization of hydration status. A number of epidemiological studies have linked markers of underhydration with an increased risk of adverse health outcomes. This Review provides an overview of the mechanisms that regulate body water balance and the adaptive responses to decreased hydration, and describes current understanding of the physiological consequences of underhydration on health outcomes. Key points: A growing number of epidemiological studies have linked markers of underhydration, such as elevated plasma vasopressin, sodium at the upper end of the normal range, low urine volume and high urine osmolality, with an increased risk of adverse health outcomes such as the future development of chronic diseases and premature mortality. Worldwide population surveys estimate that more than 50% of people drink less than recommended, indicating that consistent proper hydration may be beneficial for many individuals. Chronic underhydration results in a new steady state of water balance with constantly activated water conservation mechanisms accompanied by an accumulation of organic osmolytes and persistent vasopressin secretion. Adaptive changes to underhydration affect multiple physiological systems and may promote their deterioration. Interventional trials with increased water intake are needed to prove causality and facilitate implementation of optimal fluid intake recommendations into general clinical practice. [ABSTRACT FROM AUTHOR]

Aim: As climate change increases the frequency and severity of droughts in many regions, conservation during drought is becoming a major challenge for ecologists. Droughts are multidimensional climate events whose impacts may be moderated by changes in temperature, water availability or food availability, or some combination of these. Simultaneously, other stressors such as extensive anthropogenic landscape modification may synergize with drought. Useful observational models for guiding conservation decision‐making during drought require multidimensional, dynamic representations to disentangle possible drought impacts, and consequently, they will require large, highly resolved data sets. In this paper, we develop a two‐stage predictive framework for assessing how drought impacts vary with species, habitats and climate pathways. Location: Central Valley, California, USA. Methods: We used a two‐stage counterfactual analysis combining predictive linear mixed models and N‐mixture models to characterize the multidimensional impacts of drought on 66 bird species. We analysed counts from the eBird participatory science data set between 2010 and 2019 and produced species‐ and habitat‐specific estimates of the impact of drought on relative abundance. Results: We found that while fewer than a quarter (16/66) of species experienced abundance declines during drought, nearly half of all species (27/66) changed their habitat associations during drought. Among species that shifted their habitat associations, the use of natural habitats declined during drought while use of developed habitat and perennial agricultural habitat increased. Main Conclusions: Our findings suggest that birds take advantage of agricultural and developed land with artificial irrigation and heat‐buffering microhabitat structure, such as in orchards or parks, to buffer drought impacts. A working lands approach that promotes biodiversity and mitigates stressors across a human‐induced water gradient will be critical for conserving birds during drought. [ABSTRACT FROM AUTHOR]

When the first concrete was poured in 1949 for the Hungry Horse Dam (Montana, USA), pozzolan cements had already been used in several major North American dams, including Grand Coulee on the Columbia River (diatomaceous earth explored but ultimately not used), Friant on the San Joaquin River and Altus on the North Fork Red River (pumicite) and Bonneville on the Columbia River and Davis on the Colorado River (calcined clay). But Hungry Horse Dam stands out as the first dam constructed using coal combustion fly ash. Utilising 2.4 million cubic metres of concrete, the dam is located on the South Fork Flathead River, one of the tributaries feeding one of the nation's major waterways, the Columbia River, and closely related to the adjacent Glacier National Park. In this respect, Hungry Horse is directly connected to two momentous periods in modern history – the massive adoption in the 1950s of coal as fuel for power plants, and the ongoing threats to fresh water supply and the rapid retreat of alpine glaciers due to global warming. Two concrete cores from this dam, one with fly ash and one without fly ash, are examined microscopically to explore the long‐term suppression of alkali‐aggregate reaction by fly ash. The core without fly ash exhibits clear evidence of alkali‐aggregate reaction, manifested by sandstone coarse aggregate particles with darkened reaction rims. Sandstone coarse aggregate particles of the same lithology in the core with fly ash are without signs of alkali‐aggregate reaction. A detailed examination of the darkened rims indicates that alkali‐silica reaction products fill the narrow gaps between adjacent sand grains in the sandstone. This alkali‐silica gel infilling allows for optical continuity between adjacent sand grains and is responsible for the classic darkened rim associated with the alkali‐aggregate reaction. [ABSTRACT FROM AUTHOR]

Summary: A conceptual understanding on how the vegetation's carbon (C) balance is determined by source activity and sink demand is important to predict its C uptake and sequestration potential now and in the future. We have gathered trajectories of photosynthesis and growth as a function of environmental conditions described in the literature and compared them with current concepts of source and sink control. There is no clear evidence for pure source or sink control of the C balance, which contradicts recent hypotheses. Using model scenarios, we show how legacy effects via structural and functional traits and antecedent environmental conditions can alter the plant's carbon balance. We, thus, combined the concept of short‐term source–sink coordination with long‐term environmentally driven legacy effects that dynamically acclimate structural and functional traits over time. These acclimated traits feedback on the sensitivity of source and sink activity and thus change the plant physiological responses to environmental conditions. We postulate a whole plant C‐coordination system that is primarily driven by stomatal optimization of growth to avoid a C source–sink mismatch. Therefore, we anticipate that C sequestration of forest ecosystems under future climate conditions will largely follow optimality principles that balance water and carbon resources to maximize growth in the long term. [ABSTRACT FROM AUTHOR]

To investigate the association between mtDNA genetic information and the risk of SF, individuals were conducted in the drinking water endemic fluorosis area in northern China, sequenced the whole genome of mtDNA, identified the SNPs and SNVs, analyzed the haplogroups, and diagnosed SF, and then, the effect of mtDNA genetic information on the risk of SF was evaluated. We find that, D5 haplogroup and its specific SNPs reduced the risk, while the D4 haplogroup and its specific SNPs increased the risk of SF. The number of SNVs in coding regions of mitochondrial respiratory chain (MRC) is different between the controls and cases. This suggests that D5 haplogroup may play a protective role in the risk of SF, while the opposite is observed for the D4 haplogroup, this may relate to their specific SNPs. And SNVs that encode the MRC complex may also be associated with the risk of SF. [ABSTRACT FROM AUTHOR]

This study focuses on identifying fluoride (F‒) concentrations and its health risk assessment (HRA) in drinking water sources in south-eastern Türkiye. Groundwater quality was assessed using some graphical approaches such as Schoeller and Piper diagrams and GIS mapping. Average daily exposure dosages through oral and dermal contact exposure routes were considered to determine the potential health risk of F‒ in groundwater. Groundwater samples were taken from 53 points in spring, summer, autumn, and winter seasons. The results showed that the average annual F‒ concentrations in water resources in the study area were 0.26‒3.62 mg/L. According to the HRA results, the highest F‒ health risk in this region was observed in children, followed by teenagers and adults. This study indicated that there is a strong relationship between the high health risk (4.28 > 3.5) in children and dental fluorosis caused by high F‒ concentration in groundwater. [ABSTRACT FROM AUTHOR]

A Search was conducted in international databases including Scopus, PubMed, Embase, and Web of Science from 10 January 2005 to 15 January 2023. The risk quotient (RQ) of Estrone (E1), 17β–E2 (E2), and Estriol (E3) on the surface water resources of China was calculated by Monte Carlo Simulation (MCS) technique. The rank order of steroid hormones based on pooled (weighted average) concentration in surface water was E3 (2.15 ng/l) > E2 (2.01 ng/l) > E1 (1.385 ng/l). The concentration of E1 in Dianchi lake (236.50.00 ng/l), 17β-E2 in Licun river (78.50 ng/l), and E3 in Dianchi lake (103.1 ng/l) were higher than in other surface water resources in China. RQ related to E1, 17β-E2 and E3 in 68.00%, 88.89% and 3.92% of surface water resources were high ecological risk, respectively. Therefore, carrying out source control plans for steroid hormones in surface water sources should be conducted continuously. [ABSTRACT FROM AUTHOR]

Water availability is a limiting factor to plant development and productivity. Many drought‐induced physiological processes that affect patterns of growth, biomass allocation, and ultimately, yield, are also regulated by the red/far‐red photoreceptor phytochromes (PHYs). However, as the mechanisms and responses to drought stress vary among plant developmental phases, it is reasonable to conjecture that PHY‐dependent morphophysiological responses to drought may be different according to the plant growth stage. In this study, we submitted tomato phyB1 mutant plants to water deficit in two distinct growth stages, during vegetative and flower‐bearing reproductive phases, comparing the morphophysiological development, fruit yield and quality to wild‐type (WT). In general, phyB1 plants overcome growth limitations imposed by water availability limitations during vegetative phase, being taller and leafier than WT. Restrictions to growth are less acute for both genotypes when water deficit occurs during reproductive phase compared to vegetative phase. phyB1 yield is lower when water is limited during reproductive phase, but its fruits accumulate more soluble solids, associated with better quality. These results highlight that drought‐induced modulations in tomato growth and yield are dependent upon PHYB1 regulation and the developmental phase when water deficit is applied. [ABSTRACT FROM AUTHOR]

Central Asia consists of the former Soviet Republics, Kazakhstan, Kyrgyz Republic, Tajikistan, Turkmenistan, and Uzbekistan. The region's climate is continental, mostly semi-arid to arid. Agriculture is a significant part of the region's economy. By its nature of intensive water use, agriculture is extremely vulnerable to climate change. Population growth and irrigation development have significantly increased the demand for water in the region. Major climate change issues include melting glaciers and a shrinking snowpack, which are the foundation of the region's water resources, and a changing precipitation regime. Most glaciers are located in Kyrgyzstan and Tajikistan, leading to transboundary water resource issues. Summer already has extremely high temperatures. Analyses indicate that Central Asia has been warming and precipitation might be increasing. The warming is expected to increase, but its spatial and temporal distribution depends upon specific global scenarios. Projections of future precipitation show significant uncertainties in type, amount, and distribution. Regional Hydroclimate Projects (RHPs) are an approach to studying these issues. Initial steps to develop an RHP began in 2021 with a widely distributed online survey about these climate issues. It was followed up with an online workshop and then, in 2023, an in-person workshop, held in Tashkent, Uzbekistan. Priorities for the Global Energy and Water Exchanges (GEWEX) project for the region include both observations and modeling, as well as development of better and additional precipitation observations, all of which are topics for the next workshop. A well-designed RHP should lead to reductions in critical climate uncertainties in policy-relevant timeframes that can influence decisions on necessary investments in climate adaptation. [ABSTRACT FROM AUTHOR]

In order to investigate the role of spatiality in disparities in urban water access in the Indian city of Mumbai, this article uses the dual conceptual lens of "access-as-right" and "access-as-ability" based on the theory of access. The "access-as-right" lens allows for a focus on the role of formal policy and institutional regimes in determining disparity in water entitlements. This article argues that the spatial and structural conditionalities encoded in formal policy instruments in India, as well as the spatial and structural rationales underlying these conditionalities, are used to declare informal dwellings as spatially and structurally deficient. This "deficiency" leads to ineligibility of these dwellings for full water entitlement, creating access disparity that gravely impacts Mumbai's vulnerable urban populations. This article relies on data from formal documents and semi-structured interviews of municipal engineers, experts, academics from related fields, and activists working on urban water access issues. [ABSTRACT FROM AUTHOR]