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Increasing manganese (Mn) concentrations in source water contribute to aesthetic and health-related concerns in drinking water. The challenges with Mn in drinking water primarily arise from elevated Mn concentrations in the water supply reservoir, with the inefficacy of Mn treatment largely attributed to fluctuating Mn levels in the water source. A three-dimensional Mn cycle model in a temperate monomictic reservoir, Tarago Reservoir, and a decision support system reflecting Mn variations in the local water treatment plant have been established in previous research. This study aimed to examine Mn variations from the reservoir to raw water and treated water under the influence of wind conditions during different stages of thermal structure, and discover valuable recommendations for Mn treatment in the local water supply system. We crafted 12 scenarios to scrutinize the impact of varying intensities of offshore and onshore winds on hydrodynamic processes and Mn transport during strong thermal stratification, weak thermal stratification, and turnover. The scenario analysis revealed that, during the gradual weakening of thermal stratification, offshore wind induced a substantial amount of Mn to the upper layers near the water intake point. Conversely, onshore wind hindered the upward transport of Mn. The simulated Mn in the raw water under the 12 scenarios indicated that the timing of turnover in the Tarago Reservoir is the primary concern for Mn treatment in the water treatment plant. Additionally, close attention should be given to the frequency and intensity of offshore winds during the weakening of thermal stratification., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Multi-factor risk assessment is an important prerequisite for water quality protection and the safe operation of mega hydro-projects. As the largest long-distance inter-basin water diversion project in the world, the Middle Route of the South-to-North Water Diversion Project of China (MRSNWDPC) has been in operation for 8 years and has benefited 79 million people along the canal. However, concerns have been raised in recent years about the potential negative effects of abnormal algal proliferation in the MRSNWDPC. It is very important for the safety of water supply to carry out relevant risk analysis and formulate regulatory management. In order to quantitatively evaluate the risk of algal proliferation in the MRSNWDPC under the influence of multiple factors, a multivariate risk assessment method based on Vine Copula theory and Monte Carlo simulation was proposed. Five key factors (water temperature, flow velocity, flow rate, algal cell density, and dissolved oxygen) were used and multiple dependency models in each section of the MRSNWDPC from January 2016 to January 2019 were established to study the risk of algal proliferation under multiple scenarios. The results demonstrate that water temperature can be used as an appropriate early-warning indicator of algal proliferation. The early-warning interval (unit: °C) of water temperature in the upper, middle, and lower reaches are 26-29°C, 23-26°C, and 21-23°C, respectively. Unlike bivariate analysis, the multiple dependency model describes the relationship between variables more accurately and enriches the scenarios of multiple conditional probabilities. When the water temperature fluctuates in the early-warning interval, regulating the upstream, midstream, and downstream flow velocity to be higher than 0.6 m/s, 0.5 m/s, and 0.6 m/s, respectively, can effectively reduce the risk of algal proliferation. This research not only provides a reference for the ecological control of algae in the MRSNWDPC and similar mega hydro-projects but also enriches the application of the Vine Copula theory coupled with the random sampling method for multi-variable risk analysis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Controlling hypolimnetic hypoxia is a key goal of water quality management. Hypoxic conditions can trigger the release of reduced metals and nutrients from lake sediments, resulting in taste and odor problems as well as nuisance algal blooms. In deep lakes and reservoirs, hypolimnetic oxygenation has emerged as a viable solution for combating hypoxia. In shallow lakes, however, it is difficult to add oxygen into the hypolimnion efficiently, and a poorly designed hypolimnetic oxygenation system could potentially result in higher turbidity, weakened thermal stratification, and warming of the sediments. As a result, little is known about the viability of hypolimnetic oxygenation in shallow bodies of water. Here, we present the results from recent successful tests of side stream supersaturation (SSS), a type of hypolimnetic oxygenation system, in a shallow reservoir and compare it to previous side stream deployments. We investigated the sensitivity of Falling Creek Reservoir, a shallow (Zmax = 9.3 m) drinking water reservoir located in Vinton, Virginia, USA, to SSS operation. We found that the SSS system increased hypolimnetic dissolved oxygen concentrations at a rate of ∼1 mg/L/week without weakening stratification or warming the sediments. Moreover, the SSS system suppressed the release of reduced iron and manganese, and likely phosphorus, from the sediments. In summary, SSS systems hold great promise for controlling hypolimnetic oxygen conditions in shallow lakes and reservoirs., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Deepwater bodies such as dam reservoirs are among the most prominent water resources that supply societies' water demand. Hence, water quality in these resources requires continuous and meticulous monitoring. This study evaluated the water quality of Changuleh Dam, a dam under construction in western Iran, using the CE‐QUAL‐W2 model to predict fluctuations in sulphate (SO42−) and hydrogen sulphide (H2S) concentrations. A sensitivity analysis was conducted to assess the dependence of model outputs on input variables. Additionally, an uncertainty analysis was performed using MATLAB to address the inherent uncertainties of the input variables through an ARIMA (2, 2, 1) time series model and Monte Carlo simulations. The results indicated a high sulphate concentration averaging 955.6 mg/l, considerably exceeding the drinking water standard of 400 mg/l, identifying the reservoir as a sulphate‐rich water resource. Seasonal fluctuations of H2S concentrations were also observed in the reservoir's anaerobic bed sediments, peaking at 87 mg/l. The sensitivity analysis showed that nitrate and total dissolved solids (TDS) varied more noticeably than dissolved oxygen (DO) at different depths, with the greatest variation at 50 m. This study highlights the critical need for continuous and meticulous monitoring of water quality in dam reservoirs to meet water supply standards. Highlights: Sulfate concentrations in the reservoir exceeded drinking water standards, averaging 955.6 mg/l.Hydrogen sulfide concentrations peaked at 87 mg/l during seasonal stratification.Sensitivity analysis revealed that nitrate and TDS were more impacted by input variations than dissolved oxygen.Uncertainty analysis indicated the greatest fluctuations in sulfate and hydrogen sulfide concentrations at a depth of 50 m.Aeration of the reservoir is recommended to reduce hydrogen sulfide levels and maintain water quality. [ABSTRACT FROM AUTHOR]

Umbria is an Italian region characterized by a highly fragmented water supply and distribution system, with many small systems fed by local sources. Chlorination in these small systems faces several challenges, including strong fluctuating demand, low economic significance, and limited access to infrastructure. Due to Italian regulations, the resulting frequent noncompliance with water quality standards negatively impacts performance indicators and tariffs. This research explores the possibility of implementing a low-cost chlorination system designed to adapt to varying environmental conditions (e.g., water and environmental temperature fluctuations, changes in pH, etc.) and demands. A prototype of the device was developed and tested in the Water Engineering Laboratory of the University of Perugia, Italy, to assess its ability to apply a programmable chlorination model. The effects of electronic environmental noise, along with the reliability of water meters, thermometer measurements, dosing pump control, local logging, and remote data transmission, were tested under different conditions. The results demonstrated the instrument's readiness for field applications in pilot studies under real-world conditions. [ABSTRACT FROM AUTHOR]

Intensifying anthropogenic disturbances have caused water pollution in China in recent decades. China has a vast territory with diverse climate conditions, land use types, and human activities, leading to significant water quality variability. However, few studies have investigated nationwide spatiotemporal patterns of key water quality parameters. In this study, we analyze monthly water quality observations from 3647 gauge stations to understand how water quality changes over time and space in China. We group the stations by water resource regions and adopt Python and SPSS to analyze the spatiotemporal variability and intercorrelations of eight water quality parameters. Results indicate that the concentrations of biochemical oxygen demand of 5 days (BOD5), chemical oxygen demand (COD), dissolved oxygen (DO), ammonia nitrogen (NH3-N), total nitrogen (TN), and total phosphorus (TP) show similar spatial patterns, with higher concentrations in the northern parts than the southern regions of China. The concentrations of COD and TP are higher in the rainy season than in the dry season, while DO, NH3-N, and TN show the opposite seasonal patterns. Strong positive correlations were found between BOD and COD, NH3-N and TP. The annual cumulative distribution figures demonstrate that all parameters showed slightly lower concentrations in 2022 and 2023 than in 2021, except for DO and TN. The TN/TP ratios across different water resource regions in China are significantly higher than 16, indicating that phosphorus is the limiting factor of eutrophication. This investigation provides a comprehensive understanding of the spatiotemporal variability of water quality parameters across China. The results of this study are highly valuable for investigating mechanisms regulating water quality across large spatial scales, thus providing valuable implications for improving water quality and mitigating water pollution. [ABSTRACT FROM AUTHOR]

Water consumption dynamics lead to pressure fluctuations at network nodes, potentially associated with pipe leakages or unreliable supply within a water distribution system. Efficient management of secondary water supply system (SWSS) could enhance inflow modes of its essential component (i.e., storage tank) of potential implication on pressure control and water quality maintenance. In this study, a novel computational framework was developed to determine the optimal inflow profiles of storage tanks, where a water supply system simulation model was integrated with the particle swarm algorithm-based optimization for demand peak staggering. Experimental investigations on an example water supply system revealed that, as compared to the control of float ball valves, the optimizing regulation of SWSS tanks remarkably reduced water pressure oscillations by approximately 70%, correspondingly with the minimum pressure elevating and the maximum pressure declining among network nodes. Furthermore, the enhancing regulation schemes allowed water levels to fluctuate within an effective range, thus decreasing water retention time and facilitating associated water quality safety. Sensitivity analysis from our simulations indicates that increasingly appropriate tank number and size magnified the regulation capability, thereby reinforcing the promotion effect of optimizing control schemes on the system performance. The proposed approach is expected to provide theoretical support for optimizing the dynamic operations and management of SWSSs. [ABSTRACT FROM AUTHOR]

Researchers have been placing greater emphasis on improving the operating policies of multi-purpose reservoirs in recent years. This emphasis has addressed various issues, including water supply to demands, energy production, water quality management, and flood risk reduction. This paper uses the meta-analysis method (PRISMA) for article selection and systematic review of papers focusing on water quality management in reservoirs using simulation-optimization models. After conducting a comprehensive search, 42 papers were selected for in-depth review. This paper offers an in-depth examination of various coupled simulation and optimization models used for optimal reservoir operation, focusing on addressing water quality concerns. The findings reveal a significant preference among researchers for using genetic algorithms (GA) (55%) and multi-objective particle swarm optimization (MOPSO) (30%) for optimizing reservoir operating policies. Moreover, the analysis highlights that most (81%) of the reservoir water quality simulation models employed in these papers are one-dimensional or surrogate models. These simulation models are favored for their shorter simulation time compared to two-dimensional models. The review identifies existing gaps and proposes future directions for advancing this field. For instance, there is an opportunity to enhance both inflow prediction accuracy and reservoir water quality predictions by exploring diverse data obtained from remote sensing, unmanned aerial vehicles (drones), unmanned underwater vehicles, and numerical weather prediction models. The obtained data from different sources can be fused using artificial intelligence techniques to improve their accuracy. [ABSTRACT FROM AUTHOR]

Assessing bacterial communities across water resources is crucial for understanding ecological dynamics and improving water quality management. This study examines the functional profiles of bacterial communities in drinking water resources in Mega Manila, Philippines, including Laguna Lake tributaries, pre-treatment plant sites, groundwater sources, and post-treatment plant sites. Using eDNA sequencing, flux balance analysis, and taxonomy-to-phenotype mapping, we identified metabolic pathways involved in nutrient metabolism, pollutant degradation, antibio- tic synthesis, and nutrient cycling. Despite site variations, there are shared metabolic pathways, suggesting the influence of common ecological factors. Site-specific differences in pathways like ascorbate, aldarate, and phenylalanine metabolism indicate localized environmental adaptations. Antibiotic synthesis pathways, such as streptomycin and polyketide sugar unit biosynthesis, were detected across sites. Bacterial communities in raw and pre-treatment water showed potential for pollutant degradation such as for endocrine-disrupting chemicals. High levels of ammonia-oxidizing and sulfate-reducing bacteria in pre- and post-treatment water suggest active nitrogen removal and pH neutralization, indicating a need to reassess existing water treatment approaches. This study underscores the adaptability of bacterial communities to environmental factors, as well as the importance of considering their functional profiles in assessing drinking water quality resources in urban areas. [ABSTRACT FROM AUTHOR]

Due to the high uncertainty of model predictions, it is often challenging to draw definitive conclusions when evaluating river water quality in the context of management options. The major aim of this study is to present a statistical evaluation of the Hydrologic Simulation Program FORTRAN (HSPF), which is a water quality modeling system, and how this modeling system can be used as a valuable tool to enhance monitoring planning and reduce uncertainty in water quality predictions. The authors' findings regarding the sensitivity analysis of the HSPF model in relation to water quality predictions are presented. The application of the computer model was focused on the Ave River watershed in Portugal. Calibration of the hydrology was performed at two stations over five years, starting from January 1990 and ending in December 1994. Following the calibration, the hydrology model was then validated for another five-year period, from January 1995 to December 1999. A comprehensive evaluation framework is proposed, which includes a two-step statistical evaluation based on commonly used hydrology criteria for model calibration and validation. To thoroughly assess model uncertainty and parameter sensitivity, a Monte Carlo method uncertainty evaluation approach is integrated, along with multi-parametric sensitivity analyses. The Monte Carlo simulation considers the probability distributions of fourteen HSPF water quality parameters, which are used as input factors. The parameters that had the greatest impact on the simulated in-stream fecal coliform concentrations were those that represented the first-order decay rate and the surface runoff mechanism, which effectively removed 90 percent of the fecal coliform from the pervious land surface. These parameters had a more significant influence compared to the accumulation and maximum storage rates. When it comes to the oxygen governing process, the parameters that showed the highest sensitivity were benthal oxygen demand and nitrification/denitrification rate. The insights that can be derived from this study play a critical role in the development of robust water management strategies, and their significance lies in their potential to contribute to the advancement of predictive models in the field of water resources. [ABSTRACT FROM AUTHOR]

In mountainous watersheds, floodplain sediments are typically characterized by gravel bed layers capped by an overlying soil unit that serves as a hotspot for biogeochemical reactivity. However, the influence of soil biogeochemistry on gravel bed underflow composition remains unclear, especially during hydrological transitions that alter the vertical connectivity between overlaying soils and the underlying gravel bed. This study investigates these dynamics by measuring hydraulic gradients and water compositions over three hydrological years in a typical mountainous, low‐order stream floodplain in the Upper Colorado River Basin. Results indicate that the timing of hydrological conditions strongly influences the vertical exchanges that control water quality. Specifically, during flooding events such as beaver ponding, that induce downward flushing of the soil, anoxic conditions prevalent in the biogeochemically active soil are transferred downstream via gravel bed underflow. Conversely, snowmelt and drought conditions increase oxic conditions in the gravel bed due to diminished hydrological connectivity with the overlying soil. To compare water quality response to hydrological transitions across similar floodplain environments, we propose a conceptual model that quantifies the inundation‐induced flushing of soil porewater to measure solute exchange efficiency with the gravel bed solute convergence efficiency (SCE). This model provides a framework for quantifying biogeochemical processes in hydrological underflow systems, which is critical for water and elemental budgets in these globally important mountainous ecosystems. Plain Language Summary: Mountains are important sources of freshwater for humans and ecosystems. They are however increasingly impacted by climate change. In this paper, we investigate how changes in water availability (droughts, snowmelt, inundations) can cascade into changes in water quality (concentrations of dissolved chemical elements). We show that in mountain valleys, the zone of contact between the soil and the underlying gravel bed aquifer is important for water quality. Chemical elements from the soil can be flushed down into the gravel bed aquifer, then transported by groundwater to the stream. Chemical elements from the soil can also react with chemical elements present in the aquifer. Our research can be used to better predict the water and elemental budgets in these important mountainous systems. Key Points: Soil / gravel bed connectivity in floodplains is important for water qualitySnowmelt and drought both reduce soil / gravel bed connectivityBeaver ponding increases downward flushing to gravel bed unit [ABSTRACT FROM AUTHOR]

This paper analyses the effects of environmental flows on water quality within a highly regulated basin, focusing on the Turia River basin in the eastern Iberian Peninsula. Through water management and water quality models, a series of simulations were conducted, introducing variations in the outflows of the Loriguilla reservoir to evaluate the effects of different environmental flow scenarios on water quality, particularly at the location of the intake for the water supply to Valencia. Three environmental flow scenarios were analyzed, alongside an alternative management scenario, considering their implications on water quality and reliability of water demand. The findings of this paper, particularly the nitrate (NO3−) concentration evolution, highlight the influence of minimum e-flow and e-flow regimes on water quality within the basin. These results suggest that while modifying the current flow regime can lead to some improvements in nitrate concentrations at the Valencia supply intake point, the primary cause of high nitrate concentrations is attributed to irrigation return flow and the pre-existing contamination of the aquifer. This analysis offers valuable insights into the complexities of water quality management in regulated basins, emphasizing the need for a multi-faceted approach to address the diverse factors influencing water quality and demand supply reliability. [ABSTRACT FROM AUTHOR]

The water source reservoirs are the important urban water source in northern China. Although external pollution has been greatly improved, the internal pollutants in reservoirs continue to accumulate with the complex deposition and release processes, resulting in potential risks to water supply safety. To address the aforementioned issue, this paper proposed a simulation model of water quality named ECOlab EU1-WSR to simulate the spatio-temporal changes of water quality under the influence of internal pollution for the water source reservoirs. Based on the analysis of the water quality characteristics and the distribution of benthic vegetation in the reservoir, a three-dimensional hydrodynamic model was established based on MIKE3, the corresponding parameters and the related state variables were set, the ECOlab EU1-WSR model was established by secondly developing the original ECOlab EU1 template, and the real-time dynamic outputs of pollutant content in sediment were added to link the water quality index with sediment nutrition index for better revealing the impact of the internal pollution on the water quality. The performance of the model was evaluated by the case application on the water quality simulation of Daye reservoir and the optimization of the connection project between Daye reservoir and Xueye reservoir in Shandong Province China. The results showed that the model can accurately and simultaneously simulate the pollution in water and sediment by the comparative verification of hydrodynamics, water temperature, and water quality. Moreover, the model can effectively reflect the influence of the accumulation, deposition, and release of internal pollution on water quality by analyzing the correlation between the content of various pollution in water body and those in sediment, such as the total nitrogen and total phosphorus in the water body at the bottom of the water intake, were negatively correlated with the total nitrogen and total phosphorus in the sediments with correlation coefficients of 0.538 and 0.917, respectively. In addition, the optimal water inlet position and water flow rate of the connection project can be optimized and determined by using the model to effectively control water quality. The established model will be a useful tool for the design and management of a reservoir, the interconnection projects, and other water bodies by adaptively recoded. [ABSTRACT FROM AUTHOR]

Chlorophyll-a (Chl-a) concentration monitoring is very important for managing water resources and ensuring the stability of marine ecosystems. Due to their high operating efficiency and high prediction accuracy, backpropagation (BP) neural networks are widely used in Chl-a concentration inversion. However, BP neural networks tend to become stuck in local optima, and their prediction accuracy fluctuates significantly, thus posing restrictions to their accuracy and stability in the inversion process. Studies have found that metaheuristic optimization algorithms can significantly improve these shortcomings by optimizing the initial parameters (weights and biases) of BP neural networks. In this paper, the adaptive nonlinear weight coefficient, the path search strategy "Levy flight" and the dynamic crossover mechanism are introduced to optimize the three main steps of the Artificial Ecosystem Optimization (AEO) algorithm to overcome the algorithm's limitation in solving complex problems, improve its global search capability, and thereby improve its performance in optimizing BP neural networks. Relying on Google Earth Engine and Google Colaboratory (Colab), a model for the inversion of Chl-a concentration in the coastal waters of Hong Kong was built to verify the performance of the improved AEO algorithm in optimizing BP neural networks, and the improved AEO algorithm proposed herein was compared with 17 different metaheuristic optimization algorithms. The results show that the Chl-a concentration inversion model based on a BP neural network optimized using the improved AEO algorithm is significantly superior to other models in terms of prediction accuracy and stability, and the results obtained via the model through inversion with respect to Chl-a concentration in the coastal waters of Hong Kong during heavy precipitation events and red tides are highly consistent with the measured values of Chl-a concentration in both time and space domains. These conclusions can provide a new method for Chl-a concentration monitoring and water quality management for coastal waters. [ABSTRACT FROM AUTHOR]

Groundwater vulnerability assessment using DRASTIC is an important tool for groundwater pollution prevention and management. However, traditional DRASTIC methods are not suitable for accurate assessment of groundwater vulnerability in hilly and mountainous regions of southern China. The improved method in this paper retains the basic structure of DRASTIC, and obtains more accurate evaluation results by adding parameters and modifying parameter rating Scale and weights. Comparison of the modified DRASTIC-LY vulnerability map with the map of original DRASTIC-LY method revealed differences in 28.6% of the study area. The risk map shows that the very high vulnerability area decreased from 3.6% to 2.1%, while the high vulnerability area increased from 9.4% to 5.6%. Areas with low vulnerability increased by 10.7%, while areas with medium vulnerability increased by 4.9%. The areas with very high groundwater vulnerability are mainly distributed at the confluence of the Han River and Baojiang River, the areas with high groundwater vulnerability are mainly distributed in the southeast of Mian County, Nanzheng County, Chenggu County and Yang County, while the areas with low groundwater vulnerability are distributed in the northern part of the basin. The Pearson's correlation factor was 0.55 in the original DRASTIC model, 0.58 in the DRASTIC-LY method, and 0.65 in the modified DRASTIC-LY model, which indicated that the revised DRASTIC-LY model was more appropriate than that constructed by the original model. The vulnerability map of the DRASTIC-LY model can assist government planning and decision-making departments to facilitate water resource protection and water quality control. [ABSTRACT FROM AUTHOR]

Key Takeaways: Aesthetic water quality is an important but sometimes inadequately addressed aspect of providing a safe and reliable drinking water supply. In the United States, federal regulations provide a starting point for maintaining aesthetic water quality; however, this framework falls short of providing the tools needed to effectively implement the standards. A water safety planning approach can complement regulatory frameworks or be used as an industry standard for better management of aesthetic water quality. [ABSTRACT FROM AUTHOR]

Groundwater plays a pivotal role in water management worldwide as a renewable natural resource. The issues with water management are multifaceted and are associated with quality assessment, augmentation, distribution, reuse or recycling, pollution, and its protection from depletion and degradation. To address this issue, near the newly developed region of Dwarka, New Delhi, India, this study investigates the hydrochemistry and groundwater quality for drinking and irrigation. To assess the quality of these, several water quality parameters, such as electrical conductivity (EC), total dissolved solids (TDS), sodium (Na+), calcium (Ca2+), magnesium (Mg2+), and other ions were determined. Based on the previous parameters, the water quality index (WQI) was determined, which indicated that 87% of samples were undesirable for drinking purposes. A very high value of some parameters, such as TDS and nitrates, was of major concern. The suitability of groundwater for irrigation was estimated using parameters such as the sodium adsorption ratio (SAR) and percent sodium (Na%), which showed a low alkali hazard and indicated that the water resources were suitable for irrigation. The Piper trilinear and Chadha diagrams that are used to understand the evolution of the hydrochemistry of groundwater showed the presence of permanent and temporary hardness in the groundwater. The Wilcox and Gibbs classification inferred that the majority of groundwater samples fall under the evaporation–crystallization category, partly influenced by the water–rock interactions and aquifer materials. The results of this study are significant for drinking and irrigation purposes and indicate the need for water quality control before use. This study could be helpful for local farmers, authorities, and policymakers to interpret the current groundwater conditions of the newly developed Dwarka Region. It will help in the sustainable management and implementation of water quality control programs and make them more resilient. [ABSTRACT FROM AUTHOR]

Climate change (CC) causes extreme meteorological events such as floods, droughts, water scarcity, heat waves, wildfires, and extreme cold. CC may also damage public infrastructures such as drinking water systems (DWSs) and reduce water quality from source to tap. The objective of this review paper is to provide a critical analysis of (1) the impact of CC on the three components of the DWSs: source, treatment, and distribution; (2) the perspectives of DWS employees on CC impacts and adaptation solutions for maintaining water quality; and (3) decision support systems (DSSs) that could be used by DWS employees for CC adaptation. A bibliographic research was conducted using international databases and search engines. The search for scientific articles resulted in the selection of 5234 articles, 78 of which were analyzed in more detail for the elaboration of this scoping review. This review shows that the impacts of CC on water quality are significant, but DWS employees are not enthusiastic about developing adaption measures. This review also shows that DSSs can help DWS employees facilitate the CC adaptation process for the protection of source water, improve water treatment plant operations, and enhance routine management of water quality in the distribution system. Further research is needed to identify strategies that might increase the awareness of and interest in climate change impacts, adaptation, and the use of DSSs among DWS employees. [ABSTRACT FROM AUTHOR]

Water security is at stake today. While climate changes influence water availability, urbanization and agricultural activities have led to increasing water demand as well as pollution, limiting safe water use. We conducted a global assessment of future clean-water scarcity for 2050s by adding the water pollution aspect to the classical water quantity-induced scarcity assessments. This was done for >10,000 sub-basins focusing on nitrogen pollution in rivers by integrating land-system, hydrological and water quality models. We found that water pollution aggravates water scarcity in >2000 sub-basins worldwide. The number of sub-basins with water scarcity triples due to future nitrogen pollution worldwide. In 2010, 984 sub-basins are classified as water scarce when considering only quantity-induced scarcity, while 2517 sub-basins are affected by quantity & quality-induced scarcity. This number even increases to 3061 sub-basins in the worst case scenario in 2050. This aggravation means an extra 40 million km2 of basin area and 3 billion more people that may potentially face water scarcity in 2050. Our results stress the urgent need to address water quality in future water management policies for the Sustainable Development Goals. Here the authors find one third of global sub-basins will face severe clean water scarcity in 2050. Nitrogen pollution aggravates water scarcity in >2,000 sub-basins thus 3 billion more people will be posed with severe water scarcity in 2050. [ABSTRACT FROM AUTHOR]

The management of water resources in community systems faces several challenges when it comes to meeting the population's water demand. The efficiency of the water service provided by the Drinking Water Administrative Boards (JAAP) of the province of Los Ríos was diagnosed, through the identification of compliance (C) and non-compliance (NC), interviews and perception surveys based on the indicators: continuity of service, satisfaction with water quality, presence/absence of diseases, and perception of the work carried out by the directors of the JAAP. SPSS Statistic software was used, "Cronbach's alpha" (degree of reliability) was applied, Principal Component Analysis (PCA), KMO test (Kaiser--Meyer--Olkin Measure) showed a variable ratio of (0.78). The commonality matrix indicated a correlation criterion greater than (0.7), while the total variance explained for the principal component analysis was (76.14%). The majority of users considered it to be an optimal service, although 17.64% considered the pressure with which the water resource is received to be limiting, associating the presence of impurities. [ABSTRACT FROM AUTHOR]

A systematic study on the major ions and heavy metals was carried out for surface water resources of EB coalfield for water quality assessment, source apportionment and studying the geochemical processes controlling the surface water quality. Seasonal effect was not very prominent for the surface water quality parameters inclusive of metals, though some dilution was observed in some parameters during the monsoon season. Some of the parameters exceeded the drinking water limits like TDS, turbidity, NO3−, F−, total hardness and Mg2+ in surface water. The Fe concentrations exceeded the desirable limit of the BIS standard in about 26% of the water sample. The surface water chemistry of the EB coalfield is influenced by extensive coal mining activities. The principal component analysis of metals and health concerning anions demonstrated that the data were synthesised into three loading factors with Eigen values >1 and explaining about 71.4% of the total variance. The extracted factors seem to indicate geogenic sources, coal mining and associated transportation. The quality assessment of the surface water for irrigation suitability suggested that the calculated parameters (SAR, %Na, RSC and MH) of water to be in the range of good to permissible; however, at a few sites, SAR values and MH make it unsuitable for irrigation. Thus, the study exemplified the need for awareness about the contamination of surface water within EB coalfield area. The findingsof the present study may be useful to decision-makers in developing plans for surface water quality management and sustainable use. [ABSTRACT FROM AUTHOR]

Chromophoric dissolved organic matter (CDOM) is a significant contributor to the biogeochemical cycle and energy dynamics within aquatic ecosystems. Hence, the implementation of a systematic and comprehensive monitoring and governance framework for the CDOM in inland waters holds significant importance. This study conducted the retrieval of CDOM in Lake Khanka. Specifically, we use the GBDT (R2 = 0.84) algorithm which performed best in retrieving CDOM levels and an empirical relationship based on the situ data between CDOM and dissolved organic carbon (DOC) to indicate the distribution of DOC indirectly. The performance of the CDOM-DOC retrieval scheme was reasonably good, achieving an R2 value of 0.69. The empirical algorithms were utilized for the analysis of Sentinel-3 datasets from the period 2016 to 2020 in Lake Khanka. The potential factors that contributed to the sources of DOM were also analyzed with the humification index (HIX). The significant relationship between CDOM and DOC (HIX and chemical oxygen demand (COD)) indicated the potential remote sensing application of water quality monitoring for water management. An analysis of our findings suggests that the water quality of the Great Khanka is superior to that of the Small Khanka. Moreover, the distribution of diverse organic matter exhibits a pattern where concentrations are generally higher along the shoreline compared to the center of the lake. Efficient measures should be promptly implemented to safeguard the water resources in international boundary lakes such as Lake Khanka and comprehensive monitoring systems including DOM distribution, DOM sources, and water quality management would be essential for water resource protection and government management. [ABSTRACT FROM AUTHOR]

Safe drinking water sources are crucial for human health. Consequently, water quality management, including continuous monitoring of water quality and algae at sources, is critical to ensure the availability of safe water for local residents. This study aimed to construct statistical prediction models considering probability distributions relevant to cyanophyte cell counts and compare their prediction performance. In this study, water quality parameters at Juam Lake and Tamjin Lake, representative water sources in the Yeongsan and Seomjin rivers, South Korea, were investigated. We used a water quality monitoring network, algae alert system, and hydraulic and hydrological data measured every 7 days from January 2017 to December 2022 from the Water Environment Information System of the National Institute of Environmental Research. Using data for 2017–2021 as a training set and data for 2022 as a test set, the performances of seven models were compared for predicting cyanophyte cell counts. Environmental factors associated with algae in water sources were observed based on the monitoring data, and a prediction model appropriate for the cyanophyte distribution was generated, which also included the risk of toxicity. The extreme gradient boosting with the random forest model had the best predictive performance for cyanophyte cell counts. The study results are expected to facilitate water quality management in various water systems, including water sources. [ABSTRACT FROM AUTHOR]

Investigating drinking water quality is crucial for public health, as clean water access is a fundamental requirement for a healthy life. To comprehensively assess Karachi's drinking water quality, 152 water samples were systematically collected from five districts: Malir, Karachi West, Karachi East, Karachi South, and Karachi Central. The investigation involved analyzing various physicochemical and microbiological parameters in comparison to WHO 2011 guidelines. Additionally, integrated techniques like principal component analysis and water quality index computation offer insights into both potable and non-potable water aspects, with a focus on health-related well-being. Elevated levels of turbidity and chloride were identified across all five districts, with the residual chloride surpassing permissible limits in Karachi West and Karachi Central. Coliform and E. coli levels exhibited significant variations, with the highest mean values recorded in Karachi Central and the lowest in Karachi East. The overall analysis revealed that only 16.67%, 38.71%, 50%, 43.33%, and 58.06% of the water supply is suitable for drinking in Malir, Karachi West, Karachi East, Karachi South, and Karachi Central, respectively, while 83.33%, 61.29%, 50%, 56.67%, and 41.94% are unsuitable for drinking, posing substantial health risks. Urgent interventions in water quality management and public health are imperative to mitigate these risks associated with substandard drinking water. [ABSTRACT FROM AUTHOR]

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In view of the needs of secondary water quality evaluation and intelligent operation and maintenance management, the data quality evaluation of two major secondary water supply online monitoring indicators (residual chlorine and turbidity) was carried out, and the variance analysis and covariance analysis of the impact factors of the water quality of the four major secondary water supply were proposed, and the water quality evaluation method of secondary water supply online monitoring based on K-means clustering method and entropy value method was proposed, which was applied in the secondary water supply management system of L City, and the evaluation results provided an important reference for the secondary water supply manager. Evaluation methods can be widely applied in the water quality management of secondary water supply. [ABSTRACT FROM AUTHOR]

Cyanobacteria can exist in water resources and produce odorants. 2-Methylisoborneol (2-MIB) and geosmin are the main odorant compounds affecting the drinking water quality in reservoirs. In this study, encoding genes 2-MIB (mic, monoterpene cyclase) and geosmin (geo, putative geosmin synthase) were investigated using newly developed primers for quantitative PCR (qPCR). Gene copy numbers were compared to 2-MIB/geosmin concentrations and cyanobacterial cell abundance. Samples were collected between July and October 2020, from four drinking water sites in South Korea. The results showed similar trends in three parameters, although the changes in the 2-MIB/geosmin concentrations followed the changes in the mic/geo copy numbers more closely than the cyanobacterial cell abundances. The number of odorant gene copies decreased from upstream to downstream. Regression analysis revealed a strong positive linear correlation between gene copy number and odorant concentration for mic (R2 = 0.8478) and geo (R2 = 0.601). In the analysis of several environmental parameters, only water temperature was positively correlated with both mic and geo. Our results demonstrated the feasibility of monitoring 2-MIB/geosmin occurrence using qPCR of their respective synthase genes. Odorant-producing, gene-based qPCR monitoring studies may contribute to improving drinking water quality management. [ABSTRACT FROM AUTHOR]

This study aimed to provide a systematic overview of the progress made in utilizing remote sensing for assessing the impacts of land use and land cover (LULC) changes on water resources (quality and quantity). This review also addresses research gaps, challenges, and opportunities associated with the use of remotely sensed data in assessment and monitoring. The progress of remote sensing applications in the assessment and monitoring of LULC, along with their impacts on water quality and quantity, has advanced significantly. The availability of high-resolution satellite imagery, the integration of multiple sensors, and advanced classification techniques have improved the accuracy of land cover mapping and change detection. Furthermore, the study highlights the vast potential for providing detailed information on the monitoring and assessment of the relationship between LULC and water resources through advancements in data science analytics, drones, web-based platforms, and balloons. It emphasizes the importance of promoting research efforts, and the integration of remote sensing data with spatial patterns, ecosystem services, and hydrological models enables a more comprehensive evaluation of water quantity and quality changes. Continued advancements in remote sensing technology and methodologies will further improve our ability to assess and monitor the impacts of LULC changes on water quality and quantity, ultimately leading to more informed decision making and effective water resource management. Such research endeavors are crucial for achieving the effective and sustainable management of water quality and quantity. [ABSTRACT FROM AUTHOR]

Since 2010, New South Wales (NSW) Health has assisted local water utilities to develop and implement risk-based drinking water management systems based on the Australian Drinking Water Guidelines Framework for Management of Drinking Water Quality. This support has benefited regional communities, and especially smaller utilities, by helping to identify and control risks. NSW Health's support projects have resulted in statistically significant improvements across many elements of drinking water management system implementation. Through this program of support, NSW Health has identified possible infrastructure and operational needs and assessed implementation of drinking water management systems. In parallel, NSW Health has worked to assess the risk from Cryptosporidium in drinking water supplies and to develop a formal audit program. Findings from the NSW Health support program informed the development of two NSW Government programs and the commitment of more than $1 billion to help local water utilities address public health and other critical needs. The introduction of risk-based drinking water management systems has driven incremental improvement in drinking water quality management across the state of NSW. [ABSTRACT FROM AUTHOR]

Microbial and chemical qualities of drinking water and freshwater bodies in highly urbanized regions of developing countries remain as global knowledge gaps. This current scoping review addressed this issue in the case of Mega Manila, Philippines. Quantitative and qualitative analyses of literature were done to support syntheses and identify gaps in water quality monitoring and management. The microbial quality of freshwater bodies and drinking water within the region is indicated by the detected microbial communities, bacterial species, and genetic elements associated with drug resistance, through culture-dependent and -independent approaches. Heavy metals were found to contaminate freshwater bodies but were absent in the drinking water supply. Overall, our findings highlight the need for harmonizing monitoring tools and data to assess water safety. Outside Mega Manila, freshwater bodies and drinking water supply must be monitored. Research focusing on environmental and public health as impacted by drinking water and resources must also be prioritized. [ABSTRACT FROM AUTHOR]

The article focuses on ephemeral streams, which intermittently flow depending on rainfall or snowmelt, and their significant contribution to downstream river flows in the U.S. It discusses how despite their infrequent and short-lived nature, these streams play a crucial role in transporting water and nutrients downstream, influencing water quality and ecosystem dynamics.

Uncrewed aerial systems (UASs) are becoming very popular in the domain of water resource mapping and management (WRMM). Being a cheaper and quicker option capable of providing high temporal and spatial resolution data, UAS has become a much sought-after platform for remote sensing. Still, their application in the field is in its early stage. This paper encompasses basic concepts of UAS, different payloads and sensor technologies available, various methodologies for its application in WRMM, different software available, and challenges associated with them, thus presenting a comprehensive review of multiple applications of UAS in different sub-domains of water resources. From cryosphere, rivers and lakes, and coastal areas to sub-surface water, as well as from water quality to wastewater management, the authors have discussed various applications of uncrewed aerial vehicles. At the end of the paper, the authors have identified the issues posing problems in the wider implementation of UAS in WRMM. Also, the future scope of the UAS in WRMM has been discussed. [ABSTRACT FROM AUTHOR]

One of the pivotal decision-making tools for sustainable management of water resources for various uses is accurate prediction of water quality. In the present paper, multiple linear regression (MLR), radial basis function neural network (RBF-NN), and multilayer perceptron neural network (MLP-NN) models were developed for the monitoring and management of irrigation water quality (IWQ) in Ojoto area, southeastern Nigeria. This paper is the first to integrate and simultaneously implement these predictive methods for the modeling of seven IWQ indices. Moreover, two modeling scenarios were considered. Scenario 1 represents predictions that utilized the specific physicochemical parameters for calculating the IWQ indices as input variables while Scenario 2 represents predictions that utilized pH, EC, Na+, K+, Mg2+, Ca2+, Cl-, SO42-, and HCO3- as inputs. In terms of salinity hazard, most of the water resources are unsuitable/poor for irrigation. However, in terms of carbonate and bicarbonate impact and magnesium hazard, majority of the samples have good and excellent IWQ. Seven agglomerative Q-mode dendrograms spatiotemporally classified the water resources based on the IWQ indices. Model validation metrics showed that the MLR, RBF-NN, and MLP-NN models developed in the two scenarios performed well in both scenarios, with minor variations. [ABSTRACT FROM AUTHOR]

Water is an important resource, and it is a worldwide struggle to provide water of good quality to the whole population. Despite good governing laws and guidelines set in place to help protect the water resources and ensure it is of good quality for various consumers, the water quality in South Africa is worsening due to lack of management. The deteriorating infrastructure is becoming progressively worse, due to corruption and insufficient funds. The ever-increasing number of toxicants, as well as the identification of emerging chemicals of concern, are also challenges South Africa is facing. Chemical analysis cannot determine the total biological effect of a mixture of chemical compounds, but this shortcoming can be addressed by adding effect-based methods (EBMs) to water quality monitoring programmes. In this paper, the current status of water quality monitoring in South Africa is discussed, as well as the capacity of the country to add EBMs to its water quality monitoring programmes to protect and improve human and animal life. Created in Biorender.com [ABSTRACT FROM AUTHOR]

• Taste&Odor-producing actinobacteria has been overlooked in drinking water reservoirs. • The diversity of actinobacterial communities were significantly different in geographical space. • Stochastic processes determined the assembly process of actinobacterial communities. • Actinobacteria spores remained germination and growth under nutrient scarcity. • Actinobacteria exhibited odor-producing potential capacity in drinking water. The presence of actinobacteria in reservoirs can lead to taste and odor issues, posing potential risks to the safety of drinking water supply. However, the response of actinobacterial communities to environmental factors in drinking water reservoirs remains largely unexplored. To address this gap, this study investigated the community structure and metabolic characteristics of odor-producing actinobacteria in water reservoirs across northern and southern China. The findings revealed differences in the actinobacterial composition across the reservoirs, with Mycobacterium sp. and Candidatus Nanopelagicus being the most prevalent genera. Notably, water temperature, nutrient levels, and metal concentrations were associated with differences in actinobacterial communities, with stochastic processes playing a major role in shaping the community assembly. In addition, three strains of odor-producing actinobacteria were cultured in raw reservoir water, namely Streptomyces antibioticus LJH21, Streptomyces sp. ZEU13, and Streptomyces sp. PQK19, with peak ATP concentrations of 51 nmol/L, 66 nmol/L, and 70 nmol/L, respectively, indicating that odor-producing actinobacteria could remain metabolically active under poor nutrient pressure. Additionally, Streptomyces antibioticus LJH21 produced the highest concentration of geosmin at 24.4 ng/L. These findings enhance our understanding of regional variances and reproductive metabolic mechanisms of actinobacteria in drinking water reservoirs, providing a solid foundation for improving drinking water quality control, especially for taste and odor. [Display omitted] [ABSTRACT FROM AUTHOR]

Integrated reservoir water quantity and quality management is significant for water supply security and river ecosystem health. However, the spatiotemporal heterogeneity of water quality and the nonuniform response of multiple indicators to operation changes make it difficult to determine optimal operation schedules. This study proposes a coupled simulation-surrogate-optimization modeling approach for compromising multiple water quantity and quality targets in reservoir operations. The Environmental Fluid Dynamics Code (EFDC) was used to simulate spatiotemporal reservoir water quality dynamics. Subsequently, an ecological damage assessment method was established, accounting for the spatiotemporal heterogeneity of multiple water quality indicators and the nonlinear relationship between the water quality deterioration and ecological damage. To quickly simulate the ecological damage, a surrogate model was developed using the nonlinear autoregressive network with exogenous inputs (NARX). Finally, the surrogate model was integrated into a reservoir operation optimization model for compromising socioeconomic and ecological targets. By applying the methods to China's Danjiangkou Reservoir as a case, it was shown that more even nutrient distribution in the reservoir increased water eutrophication area while reducing concentration peak values, which helped decrease the ecological damage. Operation changes could lead to opposite effects on in-reservoir and downstream ecological targets, increasing operation optimization complexity. Both ecological and socioeconomic benefits significantly increased (by 9.4%–16.4%) during dry years under the optimized operation scheme, implying that synergies were obtained. This study offers implications and a management tool for reservoir operations to address the multiple tradeoffs among socioeconomic and ecological benefits. • Nonuniform responses of multiple water quality targets to operations are analyzed. • Ecological damage assessment considers spatiotemporal water quality complexity. • Hydrodynamic conditions affect spatial nutrient distribution and ecological damage. • Synergies among ecological and socioeconomic targets are obtained in dry years. [ABSTRACT FROM AUTHOR]

This paper presents the history and evolution of the California Department of Water Resources' Municipal Water Quality Investigations (MWQI) program. This program tracks source water quality in the Sacramento–San Joaquin Delta (Delta) for drinking water supply for nearly two-thirds of California. The program provides early warning of changing conditions in source water quality, provides data and knowledge-based support for operational decision making, and provides scientific support to a variety of urban water users. This retrospective (i) documents program formation, (ii) describes its evolution in response to regulations and technological advances in water treatment and field monitoring, and (iii) notes how the development of federal drinking water quality regulations such as the Disinfection By-Products Rule impacted the program. The MWQI program is believed to be the first drinking water supply program in the United States to conduct continuous, real-time monitoring of organic carbon, bromide, and other anions and to report these data on the internet. In addition to its regular use for operational decision making, the data may be used for evaluating long-term trends and responses to specific changes in the Delta and its watershed. Future program directions will likely be guided by factors that may trigger changes in treatment plant processes and operations, such as emerging contaminants, changes in land and water management practices, permanent Delta island flooding, sea level rise, and climate change. While this retrospective focuses on one region, its multi-decade interplay of science, treatment and monitoring technology, and regulations (as well as practical aspects of managing such a large-scale program) are broadly relevant to professionals engaged in drinking water quality management in other urbanized and developed regions of the world. [ABSTRACT FROM AUTHOR]

Considering the global climate changes that have disrupted the availability of fresh water and led to the emergence of drought, an effective management strategy for water quality must be implemented. In this work, we analyzed the possibility of used and treated water being reused and the effect of its use on soil on the development of plants. In the case of irrigation with treated wastewater, the following parameters increased: calcium carbonate equivalent, organic matter, content of phosphorus, calcium, potassium, sodium, nitrogen, biochemical oxygen consumption; chemical oxygen demand (COD), decreased sodium absorption rate, soil electrical conductivity, pH, magnesium content, and soil bulk density. Due to the micronutrients it contains, the use of treated wastewater in irrigation can be an organic fertilizer for the soil. Wastewater is a source of soil water supply. Untreated wastewater may contain, depending on the source (industry, pharmacies, medicine, households), toxic compounds, bacteria, viruses, and helminths, which, if used for long periods of time in irrigation, can have a negative impact on health and the environment, reaching the soil, the roots of the crops, and then the underground water. Therefore, these waters must be used after adequate treatment. Global climate change disrupts the availability of fresh water and negatively influences the occurrence of floods, droughts, and water quality, which is why any water source must be managed correctly. [ABSTRACT FROM AUTHOR]

The present study proposes a framework to evaluate utilizing a combined system including water treatment system and reservoir operation optimization to control water quality impact of agricultural runoff on the aquatic habitats. Soil and water assessment tool was applied in the river basin scale to simulate outflow and nitrate concentration in the target sub-basin. Furthermore, an operation optimization model of the reservoir was utilized to analyze different scenarios of using water treatment system and reservoir operation to mitigate nitrate concentration impacts. Results indicated that the reservoir should be considered as a tool for controlling water quality in combination with the water treatment system for the cases in which a constructed dam is available at upstream. According to the results in the case study, storage loss is the same in all of the scenarios. Moreover, reservoir is able to compensate reduction of the treatment system area for mitigating water quality impacts. The reliability of water supply is considerably changed in different scenarios. Analysis corroborated that using the optimal reservoir operation is the best scenario in the case study. However, it might be different in other case studies. The most important advantage of the proposed method is to provide an integrated framework to analyze combined scenarios to mitigate nitrate impact in the river basin scale. It is recommendable to utilize the proposed framework in the decision-making system to construct water treatment systems. In fact, it might reduce costs drastically. [ABSTRACT FROM AUTHOR]

Soils with low permeability horizons (e.g., claypans) are vulnerable to loss of nutrients through surface runoff along with preferential flow paths through the restrictive horizon to deeper aquifers. Partitioning between these hydrologic pathways is important to determine transport processes and develop strategies that mitigate stream contamination. Our objective was to investigate controls on groundwater chemistry and recharge pathways using natural geochemical tracers in the Goodwater Creek Experimental Watershed in Missouri, U.S. Groundwater samples were collected during 2011–2017 from 32 piezometers ranging from 0.13 to 16 m deep along with stream water and precipitation. Diagnostic tools of mixing models indicated that chemistry of perched water directly above the claypan and shallow groundwater immediately below was controlled primarily by chemical equilibrium. Five solutes behaved conservatively in most deep piezometers (>5 m), reflecting mixing of two end members and the lack of significant denitrification processes. End member mixing analysis showed that the deeper groundwater originated primarily from groundwater at similar depths, often upslope or from strata directly above, with small contributions from perched water, highlighting the importance of both horizontal and vertical preferential recharge pathways. Vertical pathways are likely dictated by soil heterogeneity throughout the critical zone and do not occur synchronously with precipitation events or simultaneously over all piezometer locations. The complex recharge pathways provide stochastic conduits for nitrate transport to deeper aquifers where legacy stores accumulate, presenting a significant challenge for water quality management in watersheds with restrictive soil horizons and spatially and temporally heterogeneous preferential flow pathways, including the Mississippi River Basin. Plain Language Summary: The transport of nutrients and herbicides to streams is a concern in the U.S. Midwest, where soils with low permeability layers, such as claypans, are extensive. These layers restrict water movement through deeper soil except when cracks form during dry periods. Determining how contaminants move through soil into surface and ground water is important to develop strategies to mitigate water contamination. Using natural geochemical tracers, we determined that deep groundwater originated primarily from groundwater at similar depths with some contributions from water above the claypan. Deep groundwater chemistry resulted from the mixing of these different sources, with little chemical transformations of the contaminants. In contrast, water chemistry above the claypan and shallow groundwater immediately below was controlled primarily by chemical transformations. Claypan cracks provide conduits for the transport of nutrients and herbicides from the surface to deeper groundwater where they accumulate. Soils with restrictive horizons and a high likelihood of cracking challenge water quality management, as deep groundwater provides a major source of high nitrate concentrations in streams. This information can help water managers and water resource agencies evaluate the effectiveness of nutrient management and mitigation practices. Key Points: Groundwater chemistry was dominated by chemical equilibrium in perched and shallow aquifers (<4 m) and mixing in the deeper aquifersGroundwater in the deeper aquifers was recharged by groundwater from similar depths and above strata but via heterogeneous pathwaysComplex recharge and nitrate transport routes pose a challenge for legacy nitrogen mitigation in regions with restrictive soil horizons [ABSTRACT FROM AUTHOR]

The control of parameters and quality attributes in water systems is a permanent objective to guarantee the quality of pharmaceutical products, such as vaccines. The objective of this work is to control the quality of purified water supplied to the production of the Active Pharmaceutical Ingredient of the Abdala vaccine against the SARS-CoV-2 virus causing Covid 19. The methodology was structured as follows: establishment of sampling points, execution of tests, data processing and evaluation of trends in compliance with quality specifications. The conductivity results were below 1,3 μS/cm, the Total Organic Carbon between 8,16 and 200 μg/L, and the mesophilic aerobic count remained between 0 and 20 cfu/mL, with the absence demonstrated of pathogenic microorganisms, which allowed to ensure that the Purified Water System the supply to Abdala's production, remain with a state of control during monitoring time. [ABSTRACT FROM AUTHOR]

A fuzzy multi-objective optimisation model was investigated for water quality management in a river under uncertain conditions. In this study, to deal with multiple pollutants simultaneously, the National Sanitation Foundation's water quality index was considered as one of the model's objective functions based on fuzzy set theory. This made it possible to investigate the overall effect of uncertainties on simultaneous changes. Another objective function was the total treatment costs for wastewater discharged into the river. A water quality simulation model and a non-dominated-archiving ant colony optimisation algorithm were used to determine the values of water quality parameters and the model's optimal solutions, respectively. Furthermore, a simulation–optimisation approach was adopted for facilitating the problem-solving process and applied to a hypothetical case study resembling a river system in Iran. The results show that the proposed model significantly reduced the total wastewater treatment costs compared with a similar single-objective model with a more cautious and a cost-effective approach. Although the treatment costs were increased compared with the similar deterministic model, more feasible approach was taken by considering the uncertainties associated with the objectives. With suitable modifications, the model could be easily adapted for other river systems. [ABSTRACT FROM AUTHOR]

The article reports that regulatory programs are not well adapted to address emerging water supply threats with collaborative solutions are needed to avoid further loss of water resources and develop new sources of supply. Topics include analyze the implications of a warming planet have found that climate change; and explains why creative and collaborative solutions are needed to maintain access to water supplies with the impacts of climate change.

To investigate the monitoring history and long-term change trends in surface water quality in China since the reform and opening up, the history of surface water environment monitoring is summarized, including monitoring scope, monitoring methods, and technical requirements. Temporal and spatial patterns of surface water quality in China were analyzed based on the monitoring results. In the past 40 years, the monitoring targets for surface water quality have been continuously improved, the frequency of monitoring has become more science-based, and the monitoring indicators are now comprehensive. Overall, the temporal change trend in surface water quality has followed a "fluctuating changes stage—rapid deterioration stage—fluctuations stalemate stage—rapid improvement stage" pattern. However, the current regional surface water quality is still in a polluted status, and there is a gap between surface water quality status and the goal of building a well-off society. At present, China's surface water pollution is prone to high numbers of incidents and the treatment of surface water pollution has entered a crucial stage. The potential for the continuous reduction of major pollutant discharges has become more challenging, and the marginal cost for pollution control has increased. It is very difficult to comprehensively solve the outstanding water environment problems. In addition to strengthening the existing work on surface water quality control, it is also necessary to strengthen the work of risk identification, early warning, and regulation implementation of the surface water environment. During the 14th year plan period (2021–2025), the overall planning on water resources, water ecology, and water quality will be implemented, and beautiful rivers and lakes will be created. [ABSTRACT FROM AUTHOR]

Water is the most important natural element present on earth for humans, yet the availability of pure water is becoming scarce and decreasing. An increase in population and rise in temperatures are two major factors contributing to the water crisis worldwide. Desalinated, brackish water from the sea, lake, estuary, or underground aquifers is treated to maximize freshwater availability for human consumption. However, mismanagement of water storage, distribution, or quality leads to serious threats to human health and ecosystems. Sensors, embedded and smart devices in water plants require proactive monitoring for optimal performance. Traditional quality and device management require huge investments in time, manual efforts, labour, and resources. This research presents an IoT-based real-time framework to perform water quality management, monitor, and alert for taking actions based on contamination and toxic parameter levels, device and application performance as the first part of the proposed work. Machine learning models analyze water quality trends and device monitoring and management architecture. The results display that the proposed method manages water monitoring and accessing water parameters efficiently than other works. [ABSTRACT FROM AUTHOR]