Unsustainable Water Use Research Articles

Spatiotemporal dynamics of the water footprint and virtual water trade in global cotton production and trade

Cotton, the world's most widely cultivated fiber crop, is associated with a multitude of environmental impacts, particularly the intensive use of water resources. While previous studies have assessed cotton's water usage through the water footprint concept, they largely focused on spatial variability, leaving temporal dynamics and the issue of unsustainable water use underexplored. This global study addressed these gaps by examining both the spatial and temporal variability of cotton's water footprint and assessing the unsustainable water footprint over time. Additionally, it explored the potential of flax as a water-efficient alternative for fiber production. Using a global gridded crop model, the study simulated yield and water use of flax and cotton from 1972 to 2018 at 30 arcmin resolution. The results showed that the global average blue, green, and total water footprint of cotton decreased by 37%, 48%, and 43%, respectively, due to yield improvements driven by improved crop cultivars, fertilizers, and better water management practices, with climate playing a minor role in these reductions. Despite this, the total water footprint of cotton production increased by 5%, with the blue water footprint rising by 17%. Additionally, unsustainable blue water usage in cotton cultivation increased from 59.3 km³/y to 70.9 km³/y between 1972-1976 and 2014–2018, with 71.1% of the unsustainable water traded virtually. USA, Pakistan, and India accounted for over 60% of this unsustainable virtual water trade. Flax, with its substantially lower water footprint, emerged as a promising alternative to reduce water consumption in fiber production. These findings offer critical insights for formulating strategies to mitigate unsustainable water use in global fiber production.

Integrated spatial priority assessment in Central Asia: Bridging biodiversity, ecosystem services, and human activities

Central Asia (CA) faces escalating threats from increasing temperatures, glacier retreat, biodiversity loss, unsustainable water use, terminal lake shrinkage, and soil salinization, all of which challenge the balance between ecological integrity and socio-economic development essential for achieving sustainable development goals. However, a comprehensive understanding of priority areas from a multi-dimensional perspective is lacking, hindering effective conservation and development strategies. To address this, we developed a comprehensive assessment framework with a tailored indicator system, enabling a spatial evaluation of CA's priority areas by integrating biodiversity, ecosystem services (ESs), and human activities. Combining zonation and geographical detectors, this approach facilitates spatial prioritization and examines ecological and socio-economic heterogeneity. Our findings reveal a heterogeneous distribution of priority areas across CA, with significant concentrations in eastern mountainous regions, river valleys, and oasis agricultural lands. We identified 184 key districts crucial for ecological and societal sustainability. Attribution analysis shows that natural factors like soil types, precipitation, and evapotranspiration significantly shape these areas, influencing human activities and the distribution of biodiversity and ESs. Multi-dimensional analysis indicates existing protected areas cover only 15% of the top 30% priority areas, revealing substantial conservation gaps. Additionally, a 38% overlap between ESs and human activities, along with 63.25% congruence in integrated areas, underscores significant human impacts on ecological systems and their dependency on ESs. Given CA's limited resources, it is crucial to implement measures that strengthen conservation efforts, align ecological preservation with socio-economic demands, and enhance resource efficiency through sustainable integrated land and water resource management.

Investigating agricultural water sustainability in arid regions with Bayesian network and water footprint theories

Water scarcity is a significant constraint in agricultural ecosystems of arid regions, necessitating sustainable development of agricultural water resources. This study innovatively combines Bayesian theory and Water Footprint (WF) to construct a Bayesian Network (BN). Water quantity and quality data were evaluated comprehensively by WF in agricultural production. This evaluation integrates WF and local water resources to establish a sustainability assessment framework. Selected nodes are incorporated into a BN and continuously updated through structural and parameter learning, resulting in a robust model. Results reveal a nearly threefold increase of WF in the arid regions of Northwest China from 1989 to 2019, averaging 189.95 × 108 m3 annually. The region's agricultural scale is expanding, and economic development is rapid, but the unsustainability of agricultural water use is increasing. Blue WF predominates in this region, with cotton having the highest WF among crops. The BN indicates a 70.1 % probability of unsustainable water use. Sensitivity analysis identifies anthropogenic factors as primary drivers influencing water resource sustainability. Scenario analysis underscores the need to reduce WF production and increase agricultural water supply for sustainable development in arid regions. Proposed strategies include improving irrigation methods, implementing integrated water-fertilizer management, and selecting drought-resistant, economically viable crops to optimize crop planting structures and enhance water use efficiency in current agricultural practices in arid regions. This study not only offers insights into water management in arid regions but also provides practical guidance for similar agricultural contexts. The BN model serves as a flexible tool for informed decision-making in dynamic environments.

Characterizing the multisectoral impacts of future global hydrologic variability

There is significant uncertainty in how global water supply will evolve in the future, due to uncertain climate, socioeconomic, and land use change drivers and variability of hydrologic processes. It is critical to characterize the potential impacts of uncertainty in future water supply given its importance for food and energy production. In this work, we introduce a framework that integrates stochastic hydrology and human-environmental systems to characterize uncertainty in future water supply and its multisector impacts. We develop a global stochastic watershed model and demonstrate that this model can generate a large ensemble of realizations of basin-scale runoff with global coverage that preserves the mean, variance, and spatial correlation of a historical benchmark. We couple this model with a well-known human-environmental systems model to explore the impacts of runoff variability on the water and agricultural sectors across spatial scales. We find that the impacts of future hydrologic variability vary across sectors and regions. Impacts are felt most strongly in the water and agricultural sectors for basins that are expected to have unsustainable water use in the future, such as the Indus River basin. For this basin, we find that the variability in future irrigation water withdrawals and irrigated cropland increase over time due to uncertainty in renewable water supply. We also use the Indus basin to show how our stochastic ensemble can be leveraged to explore the global multisector consequences of local extreme runoff conditions. This work introduces a novel technique to explore the propagation of future hydrologic variability across human and natural systems and spatial scales.

Modelling the role of multiple risk attitudes in implementing adaptation measures to reduce drought and flood losses

Human activities have increasingly affected hydrological processes in many river basins worldwide leading to changes in the severity of droughts and floods. A number of modelling studies have used system dynamic models to represent the complex dynamics generated by the interplays between the social and physical systems. Yet, attitudes towards drought and flood risk leading to the implementation of individual and collective adaptation measures are not included in current system dynamics modelling approaches. To address this gap, we developed a system dynamic model to represent the dynamics between human societies, decision-making processes, adaptation measures, and hydrological extremes. The model accounts for a society characterized by the co-existence of four types of risk attitudes and management responses: risk-neglecting, risk-controlling, risk-downplaying, and risk-monitoring. Our findings show that the presence of a prevalent social group with a certain risk attitude has a strong influence on the awareness, preparedness, and consequent losses of the other social groups. On the other hand, the homogenous presence of social groups with diverse risk attitudes leads to higher drought and flood losses due to the unsustainable water use of risk-neglecting and risk-downplaying groups. Finally, our results highlight that societies characterized by high heterogeneity in risk-attitudes tend to implement less collective measures, opting instead for individual measures by specific social groups. This emphasizes the importance of accounting for different social groups when modelling human-water dynamics to promote an integrated risk management and design more sustainable and resilient future adaptation pathways.

Why Do Farmers Over-Extract Groundwater Resources? Assessing (Un)sustainable Behaviors Using an Integrated Agent-Centered Framework

This study uses an Integrated Agent-Centered (IAC) framework to investigate the socio-psychological drivers of Iranian farmers’ unsustainable groundwater management practices. Empirical land use change analysis of US Geological Survey Landsat satellite images of the Jaz-Murian wetland region for 1990, 2010, and 2022, is combined with community surveys conducted with randomly selected farmers in five townships within the region (n = 356). Visual analysis reveals dramatic increases in agricultural land coverage, diminished water bodies, and increased salt lands over the 32-year sampled period. We use survey data to explain the socio-psychological drivers of unsustainable groundwater use that lead to these adverse environmental changes. In the IAC survey analysis, we find that variables for “expectation” and “subjective culture” have a negative influence on pro-environmental “intention”. “Intention” and “habit” have a positive influence and “contextual factors” have a negative influence on the drivers of “unsustainable water use behavior”. We conclude that situational influences, habitual process, intentional process, and normative processes must be considered together to alleviate pressure on wetland ecosystems. Policy makers must provide effective agricultural extension training, deliberative dialogue amongst farmer networks, well-governed local water markets and financial support to shift farmer short-termist economic gain-thinking towards socially-supported pro-environmental habits over the longer term.

Inter‐Basin Water Transfer Effectively Compensates for Regional Unsustainable Water Use

AbstractGlobally, a persistent decline of freshwater availability has been identified over a number of intensively irrigated agricultural regions. Large‐scale inter‐basin water transfer (IBWT) has been suggested as a key tool for stabilizing regional terrestrial water storage (TWS). However, IBWT projects are prohibitively expensive, and their large‐scale cost effectiveness remains unclear. Here we quantify the IBWT impacts on TWS trends in the North China Plain (NCP), a global hotspot for TWS depletion and IBWT. Based on in‐situ observations, remote sensing, and water balance principles, we provide a framework to disentangle complex climate and anthropogenic impacts on NCP TWS. Results show that the NCP TWS depletion rate was significantly attenuated in 2015–2021, which is primarily attributable to recently enhanced IBWT. Otherwise, the average NCP TWS would currently be 94.9 ± 4.9 mm (or 12.2 ± 0.6 km3) lower. However, the positive effect of IBWT is partly offset by increased crop water consumption (−24.1 ± 5.2 mm or −3.1 ± 0.7 km3). IBWT and agricultural management (i.e., reducing crop density) are both necessary for stabilizing future NCP TWS. Otherwise, a TWS declining trend exceeding 100 mm/year may occur under elevated CO2 conditions. As such, this study verifies the feasibility and effectiveness of IBWT for mitigating regional water shortages, as well as the crucial role of agricultural management in stabilizing regional TWS.

Urban water crises driven by elites’ unsustainable consumption

AbstractOver the past two decades, more than 80 metropolitan cities across the world have faced severe water shortages due to droughts and unsustainable water use. Future projections are even more alarming, since urban water crises are expected to escalate and most heavily affect those who are socially, economically and politically disadvantaged. Here we show how social inequalities across different groups or individuals play a major role in the production and manifestation of such crises. Specifically, due to stark socioeconomic inequalities, urban elites are able to overconsume water while excluding less-privileged populations from basic access. Through an interdisciplinary approach, we model the uneven domestic water use across urban spaces and estimate water consumption trends for different social groups. The highly unequal metropolitan area of Cape Town serves as a case in point to illustrate how unsustainable water use by the elite can exacerbate urban water crises at least as much as climate change or population growth.

Fully Distributed Water Balance Modelling in Large Agricultural Areas—The Pinios River Basin (Greece) Case Study

Robust assessments of variations in freshwater availability are essential for current and future water resource management in the Pinios River Basin (PRB), which is one of the most productive basins of Greece in terms of agriculture. To support sustainable water resources management in the PRB, we set up and calibrated the mGROWA hydrological model at a high spatial (100 m) and temporal (daily) resolution for the period 1971–2000, with particular attention given to deriving crop-specific irrigation requirements. We developed and implemented a comprehensive methodological framework to overcome data scarcity constraints in the PRB, thus enabling the derivation of high-resolution spatially continuous estimates of many input variables required for the mGROWA model. We generated estimates of spatiotemporal variations in the water balance components actual evapotranspiration, irrigation requirements, total runoff, and groundwater recharge for the PRB. In addition, through the calculation of indices, such as the potential irrigation to groundwater recharge ratio (PIQR), we demonstrate a way to identify potential unsustainable water use in irrigated agriculture. The established mGROWA model can be used both as a hydrological reference model providing continuous decision support for water resources management, focusing on irrigation water use, and a basis for climate impact studies for the PRB.

Change in agrophysical properties of the soils of the lower Amu Darya river terrain

Today, 50 percent of agricultural land in the world is moderately and severely degraded, and 12 million hectares of land are lost from agricultural use every year. Because of this, the land, which is the means of livelihood and livelihood of millions of people, is under threat. Nearly 800 million people suffer from chronic malnutrition, which in turn is directly related to land degradation, reduced soil fertility, unsustainable water use, drought, and severe biodiversity loss. According to scientific predictions, over the next 25 years, as a result of the acceleration of soil degradation processes, global food production will decrease by 12%, which will lead to an increase in food prices by 30%. This article describes the agrophysical properties of the soils of the lower reaches of Amu Darya, increasing soil fertility, effective use of land resources and development of advanced agrotechnical measures, scientifically based results of soil fertility.

Unsustainable use of surface water due to water balance miscalculation: the Culiacán River basin, Mexico

ABSTRACT The development of instruments for the administration of water use is a pending issue in both developing and developed countries. UNESCO has published guidance on determining water availability in Latin American and Caribbean countries. We applied this method to the Culiacán River basin, the most significant basin in Mexico for agricultural productivity. We find that surface water availability has been overestimated due to the inclusion of non-physical terms in the water balance equation, miscalculation of natural runoff and the omission of ecological water flow. Thus, unsustainable surface water use is allowed based on a miscalculation of physical water availability.

Modeling water inequality and water security: The role of water governance

Water Inequality, Water Security and Water Governance are fundamental parameters that affect the sustainable use of water resources. Through policy formulation and decision-making, Water Governance determines both Water Security and Water Inequality. Largely, where Water Inequality exists, Water Security is undermined through unsustainable water use practices that lead to pollution of water resources, conflicts, hoarding of water, and poor sanitation. Incidentally, the interconnectedness of Water Governance, Water Inequality and Water Security has not been investigated previously. This study modified the Gini coefficient and used a Logistics Growth of Water Resources Model (LGWR Model) to access Water Inequality and Water Security mathematically, and discussed the connected role of Water Governance. We tested the validity of both models by calculating the actual Water Inequality and Water Security of Ghana. We also discussed the implications of Water Inequality on Water Security and the overarching role of Water Governance. The results show that regional Water Inequality is widespread in some parts. The Volta region showed the highest Water Inequality (Gini index of 0.58), while the Central region showed the lowest (Gini index of 0.15). Water Security is moderately sustainable. The use of water resources is currently stress-free. It was estimated to maintain such status until 2132 ± 18 when Ghana will consume half of the current total water resources of 53.2 billion cubic meters. Effectively, Water Inequality is a threat to Water Security, results in poverty, under-development heightens tensions in water use, and causes instability. With proper Water Governance, Water Inequality can be eliminated through formulating and implementing approaches that engender equal allocation and sustainable use of water resources.

Effects of upstream activities of Tigris-Euphrates River Basin on water and soil resources of Shatt al-Arab Border River

The Tigris-Euphrates River Basin (TERB) is one of the key transboundary basins among the developing countries in the Middle East which has been significantly damaged by mismanagement, exploitation for energy production and unsustainable water use. This study aimed to evaluate the water and soil resources in the lower parts of this basin. More specifically, how the area of the Shatt al-Arab River (SAR) formed at the confluence of the Tigris and Euphrates rivers is affected in terms of quality by upstream activities. Four mathematical models of hydrodynamics, advection-dispersion in the river, and convection-dispersion in soil were used in conjunction with assessment of soil salinization by irrigation water. The soil salinization based on direct saltwater infiltration from riverbanks and soil salinization by irrigation with river water were predicted after simulating the intrusion of saline seawater by considering the tidal conditions of the SAR. The results showed that by applying six optimistic and probable scenarios of freshwater inflows for the future, changes in the water and soil quality in downstream riparian countries (Iran and Iraq) reflect this basin's developments and water allocation upstream. Regarding the possible scenario of maximum inflow reduction in the future, the findings of this study can be used to create a comprehensive view of the current condition and development challenges. This emphasizes the need for participatory crisis mitigation strategies between the upstream and downstream countries.

Global and regional models for identification of cooling technology in thermal power generation for water demand estimations in water-energy nexus studies

Water-energy nexus studies aim to connect the process of power generation with the corresponding water demand. The lack of information on the currently installed cooling systems at individual power plants is a challenge for the assessment of the water use on the power plant-level, which complicates decision-making in water management, especially in water-stressed regions. In this study, we investigate the spatial and temporal trends in cooling technology installations globally. Based on that, we propose a machine learning model for cooling technology identification on a regional and global level, which uses a combination of feature selection and classification algorithms. The global model demonstrates an average test set accuracy of 85.42%, which corresponds to only a minor underestimation of the actual global water footprint of 1.78% when the cooling technology and water footprint of individual power plant units is unknown. Apart from that, a special emphasis was placed on regions characterized by high and extremely high water stress, where mistakes in water policy planning and water management may lead to an unsustainable water use or even to an overexploitation of water resources. In these regions, the calculated test set accuracy was 80.83%, which is significantly larger than the average accuracy of a majority class model. The results and the method proposed in this study enable cooling system identification in individual power units using information available from other sources, such as the water stress score or seasonal freshwater availability in the region.

Rising agricultural water scarcity in China is driven by expansion of irrigated cropland in water scarce regions

Rising agricultural water scarcity in China is driven by expansion of irrigated cropland in water scarce regions

Water Scarcity and Climate Change in Mykonos (Greece): The Perceptions of the Hospitality Stakeholders

Climate change, unsustainable water use by the tourism sector, and short-term-based decisions by policymakers create additional stress on limited water resources in arid and semi-arid tourism destinations. Non-conventional water resources are playing an important role in making additional water available for these destinations, and the use of desalination plants has gradually increased. However, they can create additional externalities on the environment that can compromise the sustainability of the tourist destination. The decisions of key stakeholders and cooperation among them hold vital importance for the sustainability of tourism and the availability of water resources. Mykonos Island (Greece) is a globally recognized tourist destination in the Eastern Mediterranean Sea. The island has suffered significant water-scarcity problems in recent years, in particular during the peak tourist season, and desalination plants are being built to reduce stress on the water supply. The first objective of this work was to analyze the perceptions of hospitality stakeholders regarding water shortages and climate change in Mykonos. A second objective was to assess whether the same hospitality stakeholders feel that desalination plants are the solution to water scarcity in island-tourism destinations such as Mykonos. The results show that (i) hospitality stakeholders have significant awareness regarding water-scarcity problems and the impacts of climate change on tourism activity, (ii) they do not view desalination plants as the only solution to water scarcity, and (iii) they perceive a significant lack of coordination among actors who participate in the decision-making process. These results provide clues regarding the importance of awareness, coordination, and cooperation of each actor involved in the decision-making process and can be of interest to policymakers and public authorities in tourism destinations facing water-scarcity problems.

Can Tanker Water Services Contribute to Sustainable Access to Water? A Systematic Review of Case Studies in Urban Areas

Tanker water markets (TWM) supply water services in many urban areas, including those unconnected to public infrastructures. Notwithstanding, they have been associated with outcomes in conflict with sustainability goals of water policy, e.g., through inequitable and unaffordable supply or by contributing to groundwater overexploitation. So far, the literature dedicated to TWM has primarily conducted case studies embedded in diverse local contexts, which impedes the comparison and transfer of insights. In this article, we systematically summarize existing empirical knowledge on TWM and assess to what extent normative claims about the impacts of TWM on sustainability goals are supported by evidence. We use the concept of sustainable access, which combines notions of what constitutes access to water and what characterizes sustainable supply of services. The available evidence suggests that TWM have two key functions in urban water systems: (1) They provide services at otherwise unavailable levels, particularly with respect to the temporal availability and spatial accessibility of the service, and (2) they extend access to areas without or with low-quality network supply, typically low-income communities on the fringe of cities. From the perspective of sustainable access, we find that TWM can provide high service levels and thus fill a specific gap in the landscape of urban water services. Due to comparatively high prices, however, it is unlikely that these services are affordable for all. The combination of heterogeneous access to cheaper (subsidized) piped water and marginal pricing in TWM results in allocation outcomes that are not coherent with existing notions of equitable access to water. However, there is little convincing evidence that TWM necessarily result in unsustainable water use. The literature indicates that urban water governance in the studied areas is frequently characterized by a lack of effective institutions, which impedes the regulation or formalization of TWM.

Agricultural Adaptation to Reconcile Food Security and Water Sustainability Under Climate Change: The Case of Cereals in Iran.

In this study, we simulate the crop yield and water footprint (WF) of major food crops of Iran on irrigated and rainfed croplands for the historical and the future climate. We assess the effects of three agricultural adaptation strategies to climate change in terms of potential blue water savings. We then evaluate to what extent these savings can reduce unsustainable blue WF. We find that cereal production increases under climate change in both irrigated and rainfed croplands (by 2.6-3.1 and 1.4-2.3 million t yr-1, respectively) due to increased yields (6.6%-78.7%). Simultaneously, the unit WF (m3 t-1) tends to decrease in most scenarios. However, the annual consumptive water use increases in both irrigated and rainfed croplands (by 0.3-1.8 and 0.5-1.7 billion m3 yr-1, respectively). This is most noticeable in the arid regions, where consumptive water use increases by roughly 70% under climate change. Off-season cultivation is the most effective adaptation strategy to alleviate additional pressure on blue water resources with blue water savings of 14-15 billion m3 yr-1. The second most effective is WF benchmarking, which results in blue water savings of 1.1-3.5 billion m3 yr-1. The early planting strategy is less effective but still leads to blue water savings of 1.7-1.9 billion m3 yr-1. In the same order of effectiveness, these three strategies can reduce blue water scarcity and unsustainable blue water use in Iran under current conditions. However, we find that these strategies do not mitigate water scarcity in all provinces per se, nor all months of the year.

Irrigation Decision Support Systems (IDSS) for California’s Water–Nutrient–Energy Nexus

California has unsustainable use of agricultural water and energy, as well as problems of severe drought, nitrate pollution and groundwater salinity. As the leading producer and exporter of agricultural produce in the United States, 5.6 percent of California’s energy is currently used for pumping groundwater. These problems and new regulatory policies (e.g., Sustainable Groundwater Management Act, Irrigated Lands Regulatory Program) pressure growers to schedule, account and maintain records of water, energy and nutrients needed for crop and soil management. Growers require varying levels of decision support to integrate different irrigation strategies into farm operations. Decision support can come from the public or private sector, where there are many tradeoffs between cost, underlying science, user friendliness and overall challenges in farm integration. Thus, effective irrigation management requires clear definitions, decision support and guidelines for how to incorporate and evaluate the water–nutrient–energy nexus benefits of different practices and combinations of practices under shifting water governance. The California Energy Commission-sponsored Energy Product Evaluation Hub (Cal-EPE Hub) project has a mission of providing science-based evaluation of energy-saving technologies as a direct result of improved water management for irrigation in agriculture, including current and future irrigation decision support systems in California. This project incorporates end-user perceptions into evaluations of existing decision support tools in partnership with government, agricultural and private stakeholders. In this article, we review the policy context and science underlying the available irrigation decision support systems (IDSS), discuss the benefits/tradeoffs and report on their efficacy and ease of use for the most prevalent cropping systems in California. Finally, we identify research and knowledge-to-action gaps for incorporating irrigation decision support systems into new incentives and requirements for reporting water and energy consumption as well as salinity and nitrogen management in the state of California.

Application of leaf analysis in addition to growth assessment to evaluate the suitability of greywater for irrigation of Tilia cordata and Acer pseudoplatanus.

Water is the key resource in fulfilling the cooling function of plants in urban environments and needs to be supplied reliably and adequately, especially during dry periods. To avoid an unsustainable use of high-quality drinking water for irrigation, the reuse of greywater should be implemented for Green Infrastructure irrigation in the sense of the circular economy. In this study, the influence of greywater irrigation on vitality of two trees species, Tilia cordata and Acer pseudoplatanus, was determined by investigating the effect of irrigation with raw or treated greywater in comparison to municipal tap water. Plant growth parameters were measured, including leaf area, number of leaves, average leaf area and annual growth. In addition, the relative chlorophyll content was determined and image analysis was used to identify vital and necrotic leaf parts. While treatment did not affect growth after one growing season A. pseudoplatanus had significantly higher leaf necrosis (34.8%) when irrigated with raw greywater compared to treated greywater (15.5%) and tap water (5.8%). Relative chlorophyll content of T. cordata irrigated with tap water decreased over time until it was significantly lower (28.5) then the greywater treatments (34.5 and 35). Image analysis of leaves to quantify necrosis proved to be a sensitive method to quantify plant health and showed negative effects earlier than an analysis of growth. Anionic surfactants and electrical conductivity had a significant influence on plant vitality. Therefore, plant selection should take these parameters into account, when planning green infrastructure irrigated with greywater.