Water is a critical natural resource in Saudi Arabia, a region characterized by its arid and semiarid environments. Recognizing this, Crown Prince Mohammed bin Salman’s Vision 2030 places strong emphasis on conserving and maintaining natural water resources in the region as a cornerstone of Saudi Arabia’s long-term development goals. The vision emphasizes improving water efficiency, enhancing wastewater treatment, reducing reliance on nonrenewable groundwater resources, and investing in innovative desalination technologies. Hence, this survey was conducted to understand the status of water resources in Saudi Arabia, with a focus on climate change, the availability of groundwater and its recharging processes, water consumption for agricultural and irrigation activities, domestic and industrial water demands, and the productivity of wastewater treatment plants. Ultimately, a circular economy model was proposed as an effective means of optimizing water management in the region. This review is expected to facilitate a deeper understanding of Saudi Arabia’s transformation and the potential next-generation strategies that can be implemented.

The páramo is a high-altitude ecosystem characterized by its herbaceous vegetation and distribution in tropical and subtropical regions. This ecosystem is highly sensitive to environmental disturbances, making it a priority area for conservation and research due to its biodiversity and strategic ecosystem functions. Consequently, it is essential to conduct ecological and conservation studies of páramo areas within interdisciplinary frameworks that address the various environmental, geopolitical, economic, and sociocultural challenges. The objectives of this study were: (1) to identify the richness of páramos and the evolution of knowledge in research during the period from 2014 to 2023; and (2) to determine the scientific output, keyword cooccurrence in articles, and the most influential researchers in the field during the period from 2014 to 2023. The methodology employed was descriptive bibliometric analysis, involving a comprehensive search for scientific articles in the Scopus database. For parameter visualization, VOSviewer and the Bibliometrix package in R Studio were used to apply Lotka’s Law. The results show that Colombia is the leading country in scientific production in this field, playing a central role in advancing knowledge about the páramo. Furthermore, the findings indicate that the impact of climate change and intensive human activities (such as agriculture, grazing, pine plantations, and tourism) have increased the risk of páramo degradation, altering hydrological cycles and reducing its regulatory capacity. This bibliometric study provides a robust foundation for the planning of public policies aimed at conservation, sustainable water resource management, and biodiversity protection in páramo ecosystems. Therefore, it is crucial to promote research that considers the páramo as a socio-ecological system, analyzing the interactions between human actors and the natural environment, which will enable the design of more equitable and effective management policies.

Evaluating the impacts of land use/land cover change on soil moisture dynamics for sustainable water resources management in the Gojeb River sub-basin

Water resource assessment is crucial in the face of growing energy and environmental security challenges. This study focuses on the feasibility of installing a pumped-storage hydroelectric system in Boma, Democratic Republic of Congo, in response to frequent power outages. Objectives include modeling the river of the Kalamu and Congo Rivers to determine the project's viability. To do this, historical data on river levels, collected between 1960 and 2017, as well as precipitation and evaporation data collected between 1992 and 2023, were analyzed, taking into account the lack of flow data on the Kalamu River, using artificial intelligence methods, including the Random Forest approach. The results show significant fluctuations in flow rates, with periods of prolonged drought affecting water availability for the project. The study highlights significant challenges related to water resource management, including flow variability, which may compromise the effectiveness of the proposed system. It is recommended that Congo River flows be considered as a viable alternative while integrating sustainable water resource management strategies to meet local needs.

Proper estimates of evapotranspiration rates and long-term totals of evapotranspiration (ET) are crucial for scientific research and practical issues such as sustainable water resources management and resilient land use planning. Traditionally, ground-based ET measurements and observations are used, which are precise and accurate but lack broad spatial coverage. Satellite-based ET products provide spatially comprehensive estimates, although the accuracy of products in certain regions and of certain land use types remains unclear. This study therefore presents a systematic multi-product validation of three publicly available satellite- and model-based ET products (CERv2, MODIS Terra Net Evapotranspiration (MOD16) and Landsat Provisional Actual Evapotranspiration Science Product), including two recently developed products that have not yet been comprehensively evaluated using long-term in situ measurements from lysimeters and eddy covariance sites in an anthropogenically shaped region such as the German lowland region. The lowest relative deviations from measured ET were found at grassland sites (Median relative deviation: 5-54%; Root Mean Square Difference (RMSD): 0.58-1.02mm d-1). Across all three datasets, MOD16 showed the lowest deviations at nearly all sites (Median relative deviation: 10-54%; RMSD: 0.58-0.90mm d-1). In addition to validating satellite- and model-based ET using in situ measurements, we evaluated whether the ET products can reliably represent the spatial and temporal dynamics of ET to assess their suitability for regional water management and hydrological applications. For this purpose, principal component analyses (PCA) of the time series of each satellite- and model-based dataset were performed. The results show comparable spatial and temporal patterns that can be attributed to land use, water availability and long-term land use changes. Yet, differences between products and land use types became evident in the absolute ET values, even though the PCA revealed consistent dominant patterns across datasets. This suggests that the characteristic spatial and temporal patterns are consistently and reliably represented by all three datasets, regardless of underlying modelling approaches and resolution. The findings highlight the practicability of satellite- and model-based ET estimates for analysing regional and mesoscale ET patterns while also revealing their limitations in estimating absolute values due to model assumptions and spatial aggregation effects.

Multi-factor modeling of chlorophyll-a in South China's subtropical reservoirs using long-term monitoring data for quantitative analysis.

Distinguishing the hydrological impacts of anthropogenic groundwater withdrawal from natural climate variability is a critical yet complex challenge in sustainable water resource management. This study quantitatively evaluated the watershed-scale hydrological response to the increased groundwater abstraction in the Han River basin (35,770 km2) of South Korea using the Soil and Water Assessment Tool (SWAT). Groundwater use datasets for the 1970s and 2010s were constructed using groundwater statistical yearbooks. By applying the groundwater use datasets under 2010s weather conditions, we effectively isolated the specific effects of human usage. The results indicated that a rise in the annual groundwater abstraction from 9.6 to 22.3 million m3 reduced the average streamflow by 6.59%. The baseflow and groundwater recharge were identified as the most sensitive components, decreasing by 20.7% and 20.8%, respectively. Notably, intensive summer withdrawal (53% of the annual total) depleted aquifer storage, directly exacerbating streamflow reductions during the autumn and winter seasons. A flow duration analysis further confirmed that the duration of the dry season—defined by the flow exceeded for 275 days (Q275)—extended by 13 days, as the exceedance duration for the specific flow duration shifted from Q275 to Q263. These findings highlighted that excessive groundwater withdrawal compromises seasonal hydrological stability, necessitating integrated management strategies to secure the streamflow during critical dry periods.

Con el propósito de demostrar la capacidad del modelo SWAT (acrónimo de Soil & Water Assessment Tool) para llevar a cabo estudios de viabilidad destinados a la implementación de alternativas sustentables y a pequeña escala para mitigar la sobreexplotación de aguas subterráneas bajo la amenaza del cambio climático y cambio en el uso de suelo, en este artículo se han recopilado y analizado distintas investigaciones en las que se ha empleado tal herramienta para el análisis y la predicción de la dinámica de aguas superficiales y subterráneas, la erosión y sedimentación del suelo, así como estudios que incorporan la implementación de embalses, humedales y mejores métodos de gestión (BMP, por sus siglas en inglés) con objetivos hidrológicos y de conservación de suelos. Entre los resultados se identifica un número limitado de trabajos encaminados exclusivamente a determinar la viabilidad de implementar pequeñas obras de recarga hídrica. Asimismo, se observa en la mayoría de las metodologías propuestas la simulación de un escenario base previamente calibrado y validado, el cual después es modificado para simular escenarios de cambio climático, cambio en el uso de suelo, o implementación de BMP. Por último, a partir del análisis de los resultados de las distintas investigaciones se ha identificado una alta efectividad de la reforestación, terrazas paralelas, "barraginhas", presas filtrantes y las terrazas en general para reducir la producción de sedimentos y la escorrentía superficial en una cuenca, lo cual puede eventualmente favorecer la recarga hídrica.

A study on the hydraulic and pollutant removal performance of bioretention systems using plants and oyster shells.

ESKAPE pathogens contribute largely to antibiotic resistance spread via horizontal gene transfer in aquatic environments.

Reliable real-time measurement of suspended sediment mass concentration (SSC) is essential for effective environmental monitoring and management. It is also important for the operation and maintenance of hydropower schemes, particularly in managing reservoir sedimentation and mitigating turbine abrasion. However, sensor readings are strongly influenced by variable sediment properties, particularly size and shape, hindering reliable monitoring. This study systematically investigates the effects of particle size (median particle diameter d50 and Sauter Mean Diameter SMD) and shape (sphericity Ψ) on the responses of several turbidimeters and acoustic sensors (single- and multi-frequency), and develops methods for practical application. A customized recirculating cylindrical tank with a volume of 246L and a maximum upward flow velocity of 0.2 ms-1 enabled testing various natural and artificial particles (up to 2mm) across SSCs from 0.5 to 25 gl-1. We analyzed the specific outputs of the instruments, defined as the outputs divided by SSC, representing the calibration factors for each particle type. We found that for turbidimeters, the specific output scaled with inverse power-law relations of d50 as well as SMD, and decreased nearly linearly with Ψ. SMD and Ψ proved effective for combining size/shape effects and representing shape-related output, offering a basis for generalized field calibration. We developed three generic models to predict sensor output conversion factors for improved real-time SSC monitoring and calibration. The best-performing data-driven model, applied to a natural sediment sample, showed good agreement for turbidimeters but overestimated acoustic sensor response, highlighting refinement needs. The findings advance the understanding of sensor responses and support the feasibility of generic prediction models across diverse sediment types and sensor technologies. This study contributes to better informed sensor selection and calibration, directly enabling more effective and sustainable monitoring and management of water and sediment resources.

Inter-basin water diversion drives microbial homogenization and a shift from generalists to specialists.

Comprehensive evaluation and obstacle factor analysis of water security in Heilongjiang Province based on water footprint.

The waste water purification system combining nanofiltration (NF) membranes, solar- powered settling pretreatment ponds, and a multi-stage polishing chain. The aim is to treat combined pond and harvested rainwater contaminated with suspended solids, organics, nutrients and micropollutants, while using renewable energy to reduce operational carbon footprint. A detailed design of the experimental pilot is presented, along with proposed performance metrics, energy balance, and fouling control measures. Based on recent studies, nanofiltration offers high removal of micro-pollutants and hardness while solar-driven pretreatment and photocatalysis can substantially reduce organic loading, improving membrane lifetime. Expected outcomes include reduction in turbidity and BOD, significant micropollutant rejection, and a feasible low-carbon treatment pathway for decentralized pond/rainwater systems

This research analyzes water availability in the Tulancingo Valley (Hidalgo State, Mexico), a representative region with notable industrial and agricultural activities, over the period from 2013 to 2050. A conceptual model was developed and calculated with the Water Evaluation and Planning System (WEAP) simulation platform, calibrated with 2014 data, to estimate future water demand under mitigation scenarios that incorporate inertial population and industrial growth, as well as projected climate change trends. The simulation identifies the key actions that support sustainable water-resource management. Results show that agricultural groundwater demand is the dominant pressure on the aquifer, which is projected to become overexploited by 2050 (−185.65 hm3). The most effective mitigation strategies involve increasing the use of available surface water in both industrial and agricultural sectors; under these measures, the aquifer could recover and reach an annual availability of 231.7 hm3, ensuring long-term water sustainability of the valley. The modeling approach applied here offers a useful framework for similar assessments in other complex areas.

The issue of cadmium (Cd(II)) contamination of the water is a serious concern of the environmental and health problem, and this requires effective technology to remove the problem of toxic element. It is the purpose of this review paper to give an overview of several techniques of cadmium removal, such as polymer membranes and composites, adsorption using green materials, and electrochemical methods. The important conclusions are presented regarding the effectiveness of the polymer and composite membranes; e.g., the efficacy of the PES/HPEI-SH membrane that reached 99% removal of Cd(II) in 20 min with adsorption capacity of 135.59 mg/cm2, and the PVA/IC/PANI/GO nanofiber composite that indicates high adsorption of the 459 mg/g. The electrochemical process, i.e., electro-membrane extraction, exhibits 90% removal at 60 V, whereas the adsorption-based electro-membrane extraction contains an extraordinary capacity of 496.51 mg/g, using Fe@HC nanocomposites. Furthermore, the removal efficiencies of solar-powered electrocoagulation reached a percentage of 99.1% with respect to Cd(II). The review ends by stating that the tools to resolve cadmium removal problem include advanced materials and hybrid technologies and are promising, but various challenges such as membrane fouling and scalability are undeniable. Future studies ought to emphasize on improving reusability, expense effectiveness, and long-term applicability to address these challenges, thus contributing to the attainment of the United Nations Sustainable Development Goals (SDGs), particularly Goal 6: Clean Water and Sanitation, by guaranteeing the availability and sustainable management of water resources.

Abstract The escalating global demand for fresh water necessitates sustainable desalination solutions. Humidification-dehumidification (HDH) solar desalination systems offer a promising and low-impact approach to environmental sustainability. This paper details a thorough investigation into optimizing the performance of these systems. A detailed model is developed encompassing the solar collector, humidifier, dehumidifier, and condenser, incorporating governing equations for the transfer of heat and mass. This model is intended to be validated by a small-scale HDH desalination setup. Furthermore, the paper introduces a novel multi-objective heuristic gradient projection (MO-HGP) optimization technique. This method simultaneously considers objectives of maximizing freshwater production rate and system performance efficiency, leveraging heuristic principles and gradient projection to identify optimal system configurations. After applying the optimization and machine learning technique, a detailed analysis of performance improvements is compared to conventional approaches. Finally, to enhance efficiency and promote wider adoption, the research implements the integration of a solar tracking system (STS) into an existing HDH desalination unit. The theoretical and practical impacts of STS on increased solar energy collection and its direct correlation with higher freshwater production rates are analyzed. Through this integrated approach of theoretical modeling, and advanced optimization, including solar tracking, this paper demonstrates the potential for a significant average annual efficiency improvement of approximately 23%. This advancement substantially enhances the viability of solar-powered HDH desalination, particularly for remote areas with significant solar exposure and limited water availability, offering a pathway for more sustainable water resource management.

In ecologically fragile semiarid loess hilly agricultural regions, water resources constitute a critical constraint on sustainable development. Previous studies have demonstrated that landuse changes significantly affect the spatiotemporal distribution of water through vegetation cover modifications and hydrological process shifts. This study aims to predict future landuse changes and assess their impacts on water supply and demand, thereby providing a basis for sustainable water resource management. The current study employed an integrated PLUS-Markov chain approach (with a high validation accuracy, OA > 0.9 and Kappa > 0.83) complemented by the InVEST model to project landuse arrangements under three scenarios (NIS, FSS, and EDS) for Guyuan city in 2030, 2040, and 2050, and to analyze the consequent spatiotemporal evolution of water supply and demand risks. The results indicated that by 2050, the cropland under the NIS scenario decreased by 6.7%, primarily transitioning to grassland. In contrast, the FSS scenario led to a substantial increase in cropland by 10.7%, resulting in an overall reduction in built-up area. Meanwhile, the EDS scenario drove rapid urbanization, with a built-up area expansion rate reaching 2.99km²/year, largely at the expense of cropland. By 2050, landuse change was projected to exert minor influences on the regional water supply, with only a 7.8% variation projected compared with 2030 levels, whereas substantial impacts were projected for the water demand, which increased by 43.3% during the same period. Notably, approximately 90% of Guyuan's area may face water security risks by 2050, particularly in ecological reserves and urban zones, with the risk severity increasing over time. Several adaptive strategies were proposed to reconcile land-water relationships, thereby offering practical solutions for sustainable agroecosystem management in semiarid loess hilly regions.

Water systems experience increasing sustainability challenges from climate variability, aging infrastructure, and energy and chemical intensity demands, but AI has typically been assessed against prediction accuracy rather than demonstrated operational success. This PRISMA 2020 systematic review analyzed the role of AI solutions on sustainability in distribution, treatment, and basin management. The database search identified 920 records; after deduplication (n = 185), screening was conducted on n = 735 titles/abstracts and examination of the full text for n = 85, providing a total of n = 41 included peer-reviewed studies for qualitative synthesis and n = 38 for quantitative/bibliometric synthesis with the additional analysis of seven grey-literature sources. Evidence mapping reveals high growth post-2020, and distribution and wastewater operations are dominated by a few companies. The most deployable evidence is found with monitoring, anomaly/leak detection, and short-term forecasting, while optimization and reinforcement-learning control are primarily simulation validated with limited field applications. While accuracy metrics are often reported, transformation into water saved, kWh/m3, chemicals, compliance/reliability/resilience/equity measures are inconsistently and less frequently operationalized. In general, AI is most believable when it is part of analysis-ready workflows, bounded decision support, and measurement-and-verification.

ABSTRACT Evapotranspiration (ET) is the sum of evaporation and plant transpiration. In Brazil, climatic (humid and semiarid) and biogeographic (e.g., Atlantic Forest—humid and Caatinga—seasonally dry) contrasts influence ET dynamics. This study analyses the spatial and temporal profiles and trends of ET in seasonally humid (Atlantic Forest) and seasonally dry (Caatinga) biomes. Monthly actual ET data (MOD16 Product), precipitation data (INMET) and land cover data (MapBiomas Brazil) from 2001 to 2020 were used. The spatiotemporal characterisation was performed for the dry and rainy quarters and annually. Hypothesis tests (Mann–Kendall, Sen's slope estimator and Pettitt) were applied. Results showed that ET gradually decreases from east (Atlantic Forest) to west (Caatinga) and is consistently higher during the rainiest quarter. On an annual scale, the average accumulated ET is 827.9 mm/year, ranging from 182.6 mm/year (Caatinga) to 2225.9 mm/year (Atlantic Forest). We found that in years/months with higher ET values, rainfall was above average. In other words, ET is positively correlated with precipitation ( r = 0.20–0.67), with 5% statistical significance. Significant trends ( p < 0.05) in ET were identified, with opposing patterns. In the southeastern Atlantic Forest, reductions of up to −15 mm/year predominated. In the Caatinga biome, 97.9% of the areas with trends exhibited decreasing ET, indicating an association with deforested regions. On the other hand, some isolated areas in both biomes presented localised increases in ET. We can conclude that ET variations/trends are important indicators of moisture availability and the impacts of improper land management (deforestation). Therefore, a need exists for public policies aimed at vegetation conservation, sustainable water resource management, and the planning of adaptation strategies.