Editor’s Choice Articles

Remotely sensed flood extents obtained in near real-time can be used for emergency flood incident management and as observations for assimilation into flood forecasting models. High-resolution synthetic aperture radar (SAR) sensors have the potential to detect flood extents in urban areas through clouds during both day- and night-time. This paper considers a method for detecting flooding in urban areas by merging near real-time SAR flood extents with model-derived flood hazard maps. This allows a two-way symbiosis, whereby currently available SAR urban flood extent improves future model flood predictions, while flood hazard maps obtained after the SAR overpasses improve the SAR estimate of urban flood extents. The method estimates urban flooding using SAR backscatter only in rural areas adjacent to urban ones. It was compared to an existing method using SAR returns in both rural and urban areas. The method using SAR solely in rural areas gave an average flood detection accuracy of 94% and a false positive rate of 9% in the urban areas and was more accurate than the existing method. Full article

The Water-Energy-Food (WEF) nexus describes the synergies and trade-offs between water, energy and food. Despite the significant attention that the WEF nexus has received in recent years, challenges remain, primarily related to gaps in integrated data, information and knowledge related to the most critical inter-linkages and their dynamics. These WEF nexus complexities and uncertainty make decision-making and future forecasting extremely difficult. Policy makers and other stakeholders are currently faced with the task of understanding longer term environmental impacts and tJhe benefits and limitations of innovations that could be potentially beneficial, such as Anaerobic Digestion as a waste solution or insect protein production. This paper describes an approach to support decision making for local-level innovations within the WEF nexus by creating a set of sustainability indicators and an accompanying interactive visualisation. The indicators were derived from stakeholder consultation processes and workshops, and they were selected to include a much broader assessment than just financial aspects when considering the viability of such innovations. By taking this bottom-up approach and placing stakeholders at the heart of the project, we produced a visualisation tool to support sustainable decision making when considering the implementation of WEF innovations. Considering other, often overlooked factors and giving greater priority to these deepens knowledge and the recognition of influential issues that in conventional processes may be overlooked. This visualisation tool is designed to support decision makers to engage in a exploration of the different interlinkages, and to be the basis of stakeholder dialogue around sustainability. The visualisation tool developed was designed to be easily modifiable in order to be updated with new insights and to include other future innovations. Full article

Field measurements of bed elevation and related wave events were performed within a tidal marsh, on two cordgrass species, Spartina anglica (exotic) and Spartina maritima (native), in the Bay of Arcachon (SW France). Bed- and water-level time series were used to infer on the sediment behavior patterns from short to long term. A consistent response was found between the bed-level variation and the wave forcing, with erosion occurring during storms and accretion during low energy periods. Such behavior was observed within the two species, but the magnitude of bed-level variation was higher within the native than the exotic Spartina. These differences, in the order of millimeters, were explained by the opposite allocation of biomass of the two species. On the long term, the sedimentation/erosion patterns were dominated by episodic storm events. A general sediment deficit was observed on the site, suggested by an overall bed-level decrease registered within both species. However, further verification of within species variation needs to be considered when drawing conclusions. Despite possible qualitative limitations of the experimental design, due to single point survey, this work provides original and considerable field data to the understanding the different species ability to influence bed sediment stabilization and their potential to build marsh from the mudflat pioneer stage. Such information is valuable for coastal management in the context of global change. Full article

In tide-dominated estuaries, maximum-turbidity zones (MTZs) are common and prominent features, characterized by a peak in suspended-sediment concentration (SSC) associated with estuarine processes. The Brazilian Amazon coast includes many estuaries, experiencing macrotidal conditions. MTZs are expected to occur and are crucial for sediment delivery to the longest continuous mangrove belt of the world. The area is under influence of the Amazon River plume (ARP), the main SSC source, as local rivers do not deliver substantial sediment supply. To assess the processes that allow the ARP to supply sediment to the estuaries and mangrove belt along the Amazon coast, the results from previous individual studies within five Amazon estuaries (Mocajuba, Taperaçu, Caeté, Urumajó and Gurupi) were compared with regards to SSC, salinity, morphology and tidal propagation. This comparison reinforces that these estuaries are subject to similar regional climate and tidal variations, but that their dynamics differ in terms of distance from the Amazon River mouth, importance of the local river sediment source, and morphology of the estuarine setting. The Urumajó, Caeté and Gurupi are hypersynchronous estuaries where perennial, classic MTZs are observed with SSC > 1 g·L⁻¹. This type of estuary results in transport convergence and MTZ formation, which are suggested to be the main processes promoting mud accumulation in the Amazonian estuaries and therefore the main means of mud entrapment in the mangrove belt. The Mocajuba and the Taperaçu estuaries showed synchronous and hyposynchronous processes, respectively, and do not present classic MTZs. In these cases, the proximity to the ARP for the Mocajuba and highly connected tidal channels for the Taperaçu estuary, assure substantial mud supply into these estuaries. This study shows the strong dependence of the estuaries and mangrove belt on sediment supply from the ARP, helping to understand the fate of Amazon River sediments and providing insights into the mechanisms providing sediment to estuaries and mangroves around the world, especially under the influence of big rivers. Full article

The catalytic activity of Pd/ZrO₂ was studied in terms of the degradation of rhodamine-B dye in the presence of hydrogen peroxide. Pd/ZrO₂ was prepared by impregnation method, calcined at 750 °C and characterized by XRD, SEM and EDX. The catalyst showed good catalytic activity for dye degradation at 333 K, using 0.05 g of the catalyst during 5 h. The reaction kinetics followed the pseudo-first order kinetics. The Freundlich, Langmuir and Temkin isotherms were applied to the data and the best fit was obtained with Freundlich isotherm. Thermodynamic parameters, like ΔH, ΔG and ΔS were also calculated. The negative values of ΔH (−291.406 KJ/mol) and Gibbs free energy (ΔG) showed the exothermic and spontaneous nature of the process. The positive ΔS (0.04832 KJ/mol K) value showed suitable affinity of catalyst for dye degradation. The catalyst was very stable, active and was easily separated from the reaction mixture by filtration. It can be concluded from the results that the prepared catalyst could be effectively used in dyes degradation/removal from water subjected to further validation and use for various dyes. Full article

In this study, China’s virtual water trade was measured on the basis of multi-region input/output tables, and its influencing factors of change were decomposed. The results revealed that virtual water export and import increased from 161.5 billion tons and 114.07 billion tons in 2007 to 193.31 billion tons and 157.1 billion tons in 2014, respectively. Eight economies accounted for more than 50% of China’s total virtual water export and import, whereby the total of the United States, Japan, and Europe reached 44% (export) and 31.3% (import). The export scale, export of intermediate products, export industry structure, domestic water consumption coefficient, and domestic intermediate input structure were the main factors of the change in virtual water export. The growth of export scale was the primary reason for the growth of virtual water export. A decline in the domestic water consumption coefficient was the primary reason for the restrained growth of virtual water export. The import scale, import of intermediate products, import industry structure, water consumption coefficient of foreign countries, and the correlation among domestic industries were the main factors affecting the change in virtual water import. The growth of import scale was the primary reason for the growth of virtual water import in most sectors. A decline in the water consumption coefficient abroad was the primary reason for the restrained growth of virtual water import. Full article

Many countries are confronted with a striking problem of morbidity of fluorosis that appears because of an increased concentration of fluorides in drinking water. The objective of this study is to explore opportunities for removal of fluoride from aqueous solutions using cheap and easily accessible adsorbents, such as exhaustive coffee grounds and iron sludge and to establish the efficiency of fluoride removal. Twelve doses (1, 2, 3, 4, 5, 6, 10, 20, 30, 40, 50 and 60 g/L) of adsorbents were used and five durations of the sorption process (30, 60, 90, 120 and 150 min). The results showed that the most optimum dose of iron sludge for 3 mg/L of fluoride removal was 30 g/L and the contact time was 30 min, the efficiency of fluoride removal achieved 62.92%; the most optimum dose of exhausted coffee grounds was 60 g/L with the most optimum contact time of 60 min; at a dose of 50 g/L with contact time of 90 min, the efficiency of fluoride removal achieved 56.67%. Findings demonstrate that adsorbents have potential applicability in fluoride removal up to the permissible norms. Full article

Cryptosporidium is a major cause of diarrhoea outbreaks linked to swimming pools, but little is known about the frequency of contamination. The primary aim was to investigate the occurrence and concentration, through sampling and modelling, of Cryptosporidium oocysts in leisure pools. Secondary aims were to compare detections with operational parameters, provide the evidence-base for guidance, and improve sampling capacity and interpretation for public health investigations. Up to 1000 L pool water was sampled during swim sessions once weekly for 10 weeks from 8 August 2017 at six volunteer pools. Oocysts were detected by microscopy in 12/59 (20%) pool water samples, at least once in each pool; 8/12 (66%) detections were in August when bather loads were highest. At three pools, 1 L filter backwash was sampled weekly and oocysts were detected in 2/29 (7%) samples, following detections in pool water. The probabilities of a bather contaminating the pool ranged from 1 in 1000 to over 1 in 10,000. Monte Carlo analysis showed that when high bather numbers caused contamination on over 70% of days, multiple events per day were more likely than single events. In these generally well-managed leisure pools, Cryptosporidium risk related to high bather loads. We conclude that public awareness campaigns for bather hygiene, and reminding pool operators of current guidance for managing faecal accidents, should be ahead of peak swim season. Full article

An approach for the remediation of heavy metal-contaminated wastewater that is gaining increasing attention is the application of hydroxyapatite (HAP)-based particles. HAP is conventionally synthesized through wet chemical precipitation of calcium and phosphate ions, although later studies have focused on HAP synthesis from solid calcite contacted with a phosphate solution under ambient conditions. This synthesis route can allow saving soluble Ca-chemicals and, thus, make the process more cost-efficient. The aim of this study was to coat natural calcite powder with a layer of HAP for the removal of Zn and Cu from contaminated water. For this purpose, a HAP layer was synthesized on calcite particles, characterized using several complementary techniques and evaluated for the removal of Zn and Cu from synthetic solutions. Sorption kinetics and equilibrium isotherms, as well as the effect of sonication of the synthesized sample on its sorption performance, were determined. The results showed that calcite particles were efficiently coated with a HAP layer with high capacity in removing Zn and Cu from acidic solutions, with a q_max of 34.97 mg/g for Zn (increased to 37.88 g/mg after sonication of the sample) and 60.24 mg/g for Cu (which hardly varied with sonication). The mechanisms behind the sorption of Zn and Cu onto HAP, inferred from pH changes, the relation between metal uptake and Ca²⁺ release and XRD analysis, included surface complexation, ion exchange and precipitation of new Zn- and Cu-containing phases. Full article

The interaction between fluids and tectonic structures such as fault systems is a much-discussed issue. Many scientific works are aimed at understanding what the role of fault systems in the displacement of deep fluids is, by investigating the interaction between the upper mantle, the lower crustal portion and the upraising of gasses carried by liquids. Many other scientific works try to explore the interaction between the recharge processes, i.e., precipitation, and the fault zones, aiming to recognize the function of the abovementioned structures and their capability to direct groundwater flow towards preferential drainage areas. Understanding the role of faults in the recharge processes of punctual and linear springs, meant as gaining streams, is a key point in hydrogeology, as it is known that faults can act either as flow barriers or as preferential flow paths. In this work an investigation of a fault system located in the Nera River catchment (Italy), based on geo-structural investigations, tracer tests, geochemical and isotopic recharge modelling, allows to identify the role of the normal fault system before and after the 2016–2017 central Italy seismic sequence (Mmax = 6.5). The outcome was achieved by an integrated approach consisting of a structural geology field work, combined with GIS-based analysis, and of a hydrogeological investigation based on artificial tracer tests and geochemical and isotopic analyses. Full article

In the context of climate variability and hydrological extremes, especially in arid and semi-arid zones, the issue of natural risks and more particularly the risks related to rainfall is a topical subject in Algeria and worldwide. In this direction, the spatiotemporal variability of precipitation in the Wadi Cheliff basin (Algeria) has been evaluated by means of annual time series of precipitation observed on 150 rain gauges in the period 1970–2018. First, in order to identify the natural year-to-year variability of precipitation, for each series, the coefficient of variation (CV) has been evaluated and spatially distributed. Then, the precipitation trend at annual scale has been analyzed using two nonparametric tests. Finally, the presence of possible change points in the data has been investigated. The results showed an inverse spatial pattern between CV and the annual rainfall, with a spatial gradient between the southern and the northern sides of the basin. Results of the trend analysis evidenced a marked negative trend of the annual rainfall (22% of the rain gauges for a significant level equal to 95%) involving mainly the northern and the western-central area of the basin. Finally, possible change points have been identified between 1980 and 1985. Full article

This study introduces a hydro-climatic extremes assessment framework that combines the latest climate simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6) HighResMIP with the Soil and Water Assessment (SWAT) model, and examines the influence of the different climate model resolutions. Sixty-six hydrological and environmental flow indicators from the Indicators of Hydrologic Alteration (IHA) were computed to assess future extreme flows in the Kelantan River Basin (KRB), Malaysia, which is particularly vulnerable to flooding. Results show that the annual precipitation, streamflow, maximum and minimum temperatures are projected to increase by 6.9%, 9.9%, 0.8 °C and 0.9 °C, respectively, by the 2021–2050 period relative to the 1985–2014 baseline. Monthly precipitation and streamflow are projected to increase especially for the Southwest Monsoon (June–September) and the early phase of the Northeast Monsoon (December) periods. The magnitudes of the 1-, 3-, 7-, 30- and 90-day minima flows are projected to increase by 7.2% to 8.2% and the maxima flows by 10.4% to 28.4%, respectively. Lastly, changes in future hydro-climatic extremes are frequently quite different between the high-resolution and low-resolution models, e.g., the high-resolution models projected an increase of 11.8% in mean monthly flow in November-December-January compared to 3.2% for the low-resolution models. Full article

The subsurface beneath cities commonly shows a temperature anomaly, a so-called Subsurface Urban Heat Island (SUHI), due to anthropogenic heat input. This excess heat has multiple effects on groundwater and energy resources, such as groundwater chemistry or the efficiency of geothermal systems, which makes it necessary to investigate the temporal development of a SUHI. For this purpose, temperature profiles of 38 observation wells in the German city of Nuremberg were evaluated from 2015 to 2020 and the measured temperature changes were linked to the surface sealing. The results show that the groundwater temperatures changed between −0.02 K/a and +0.21 K/a, on average by +0.07 K/a during this period. A dependence between the temperature increase and the degree of sealing of the land surface was also observed. In areas with low surface sealing of up to 30% the warming amounts were 0.03 K/a on average, whereas in areas with high sealing of over 60% significantly higher temperature increases of 0.08 K/a on average were found. The results clearly emphasize that the subsurface urban heat island in its current state does not represent a completed process, but that more heat energy continues to enter the subsoil within the city than is the case with near-natural land surfaces. Full article

Forest operations engineering deals with all the essential infrastructure operations aiming at the efficient management of forested areas, which constitutes a prerequisite for the development of mountainous economies. Thus, the need for addressing this objective in an effective way, in conjunction with other issues associated with the protection and preservation of forest wealth, is of utmost importance. There are a whole range of forest operations for which a decision-making web-tool can potentially be utilized. This paper introduces an online decision-making tool for managing forest roads, which uses information derived from rainfall-runoff simulation. The proposed tool can be used to provide information about forest works maintenance and damage prevention in a forest environment. Furthermore, the tool assists in visualizing forest operations and achieves the optimization of their management. The development of the decision-making tool is also described, and a real case study (the Koupa watershed) is presented in detail to demonstrate its application and resulting advantages. The rainfall-runoff simulation was conducted for ten sub-basins in order to evaluate the efficiency of the corresponding culverts in the Koupa watershed. Full article

This study used the standardized precipitation index (SPI) and the standardized runoff index (SRI) to analyze dry and humid conditions in the hill-country catchment area of the Laborec River (Slovakia) over a period of 50 years (1970–2019). Analysis of the SPI and SRI over various time scales showed the occurrence of wet periods (index > 1.0) that were associated with precipitation exceeding the long-term norm, and dry periods (index below −1.0), which were the result of small amounts of precipitation. Analysis of the correlation between the SPI and SRI on different time scales revealed that the catchment showed a weaker response to precipitation over short time scales (1 and 3 months) and a stronger response over longer accumulation periods (6, 9, and 12 months). The highest annual correlation coefficient (r = 0.72) was recorded between SRI-6 at the Humenne hydrometric station and SPI-9 at the Medzilaborce meteorological station in the upper part of the catchment area. The strongest annual correlation (r = 0.69) was obtained between the Izkovce and Kamenica stations in the lower part of the catchment area. As shown by the cross-relationships examined over different periods of accumulation of flows and precipitation, hydrological droughts appeared as a result of the occurrence of meteorological droughts with a three-month delay. The conducted analysis showed that in the case of the Laborec river catchment area, there was a strong correlation between the occurrence of meteorological drought and hydrological drought. Full article

This study mainly aims to investigate carbon status according to the Pollution Haven Hypothesis (PHH) in developing countries such as India and China based on annual time series data from 1980 to 2016. The recently developed bootstrap autoregressive distributed lag procedure is applied to observe the long-run effect of FDI, hydropower, and coal-based fossil fuel consumption on three repressive measures of carbon emissions. The empirical results of the analysis show that hydropower and coal consumption lead to an upsurge in carbon emissions and the size of the carbon footprint in China. Similarly, Chinese FDI increases the carbon footprint. Moreover, Indian FDI and coal consumption accelerate carbon emissions while hydropower has no impact on environmental degradation. These results suggest that the PHH exists in China and India and that the validity of the PHH varies according to differing carbon indicators. Based on the empirical results, effective policy practices can be implemented by replacing coal and hydropower with more effective renewable energy sources and allowing foreign investors to pursue environmental concerns in the fight against environmental degradation. Full article

In this study, the SWAT hydrological model was used to estimate the sediment yields in the principal drainage basins of the Congo River Basin. The model was run for the 2000–2012 period and calibrated using measured values obtained at the basins principal gauging station that controls 98% of the basin area. Sediment yield rates of 4.01, 5.91, 7.88 and 8.68 t km⁻² yr⁻¹ were estimated for the areas upstream of the Ubangi at Bangui, Sangha at Ouesso, Lualaba at Kisangani, and Kasai at Kuto-Moke, respectively—the first three of which supply the Cuvette Centrale. The loads contributed into the Cuvette Centrale by eight tributaries were estimated to be worth 0.04, 0.07, 0.09, 0.18, 0.94, 1.50, 1.60, and 26.98 × 10⁶ t yr⁻¹ from the Likouala Mossaka at Makoua, Likouala aux Herbes at Botouali, Kouyou at Linnegue, Alima at Tchikapika, Sangha at Ouesso, Ubangi at Mongoumba, Ruki at Bokuma and Congo at Mbandaka, respectively. The upper Congo supplies up to 85% of the fluxes in the Cuvette Centrale, with the Ubangi and the Ruki contributing approximately 5% each. The Cuvette Centrale acts like a big sink trapping up to 23 megatons of sediment produced upstream (75%) annually. Full article

The effect of adsorbent dose and initial concentration on removing the azo-anionic dyes Congo Red andtartrazine present in a synthetic aqueous solution was studied using natural cellulose (CC) and modified cationic cellulose (MCC) from coconut mesocarp. Three levels of adsorbent dosage (5, 8 and 12 mg/L) and initial concentration (40, 70 and 100 mg/L) were used. Cetyl trimethyl ammonium chloride (CTAC) was used as a modifying agent. TGA and DSC showed that the extracted cellulose was of good quality, composed mostly of cellulose with lignin and hemicellulose traces, and 8% moisture. The FTIR spectrum showed the effectiveness of the modification in the structure of the material with symmetric deformation of the C₆H₆-Cl group in 1472 cm⁻¹ present in the CTAC. It was found that decreasing the adsorbent dosage and increasing the initial concentration favored the dyes’ adsorption capacity on the two bioadsorbents. Tartrazine removals of 5.67 mg/g on CC and 19.61 mg/g on MCC were achieved, and for CR of 15.52 mg/g on CC and 19.99 with MCC with removal percentages over 97% with the quaternized biomass in all cases. The kinetic and equilibrium study was carried out to identify the mechanisms involved in the adsorption process. The Freundlich model can describe the equilibrium isotherm data of tartrazine on CC and MCC. In contrast, those of CR is defined by the Langmuir and Dubinin–Radushkevic models for CC and MCC, respectively Adsorption kinetics showed that equilibrium was reached at 30 min, with rapid adsorption in the initial minutes with the removal of about 97% of the contaminant in the first 5 min; fitting to kinetic models showed that the kinetics of tartrazine on CC was fitted by Elovich (R² = 0.756), and on MCC the Elovich (R² = 0.887) and pseudo-second-order (R² = 0.999) models. Removing CR on CC was fitted by pseudo-first-order, pseudo-second-order and Elovich models (R² > 0.98), and when using MCC, all models show a good fitting with R² = 0.99 in all cases. Full article

Sustainability and efficiency in irrigation are essential in the management of the water–energy–food nexus to reach the Sustainable Development Goals in 2030. In irrigation systems, the reduction of energy consumption is required to improve the system efficiency and consequently the sustainability indicators of the water network. The use of pumps working as turbines (PATs) has been a feasible solution to recover the excess of energy where pressure reduction valves are installed. This research demonstrates the use of PATs under steady and unsteady conditions by analyzing the application in a real irrigation networks located in Vallada (Valencia, Spain). The study shows the possibility of recovering 44 MWh/year using PATs installed upstream of the irrigation hydrants. The real behavior of the PAT operation in a stand-alone recovery energy solution allowed analysis of the flow, head and efficiency variation as a function of the rotational speed, as well as the minimum capacitance to self-excite the generator and the resistive load of the electrical circuit. The PAT limit is examined in terms of the overpressure induced by a fast closure manoeuvre of hydrants, and the runaway conditions due to the disconnection from the electrical load. Full article

River deltas have received considerable attention due to coastal land loss issues caused by subsidence, storms, and sea level rise. Improved understanding of deltaic processes and dynamics is vital to coastal restoration efforts. This paper describes the application of process-based morphodynamic models to a prograding river delta. The analysis focuses on the flow and sediment dynamics amongst the interconnected channel network of the delta. The models were validated against observations of velocity and sediment concentrations for the Wax Lake Delta (WLD) of the Atchafalaya River system in Louisiana, USA. The WLD provides an opportunity as a natural laboratory for studying the processes associated with river dominated deltaic growth. It includes a network of bifurcated channels that self-organize and dynamically adjust, as the delta grows seaward to the Gulf of Mexico. The model results for a flood event show that 47% of the flow exits the system as channelized flow and the remaining 53% exits as overbank flow. The fine sediment (silt and clay) distribution was proportional with water fluxes throughout the channel network, whereas sand distribution was influenced by geometric attributes (size, invert elevation, and alignment) of the distributary channels. The long-term deltaic growth predicted by the model compares well with the observations for the period 1998–2012. This paper provides insights on how the distribution of flow and sediment amongst the interconnected delta channels influences the morphodynamics of the delta to reach a dynamic equilibrium within this relatively young deltaic system. Full article

Spillways with Highly Converging Chutes (HCCs) are a non-conventional alternative that can be applied to achieve a higher outflow capacity when the weir length exceeds the width of the valley at the toe of gravity or arch dams. This kind of spillway has been used in the past, but no general studies have yet been published. This article summarizes experimental research work aiming to increase the knowledge of the effect of some design parameters of HCCs on the energy dissipation in the stilling basin at the toe of the dam. As a comparison reference, we use the Type I stilling basins, widely known by the technical dam engineering community. The obtained results show that spillways with HCCs are a promising alternative to traditional designs, combining the ability to increase the weir length with a high capacity to dissipate energy through the impingement effect of the frontal and the side jets inside the stilling basin. Full article

This study investigates the removal of microplastics from wastewater in an urban wastewater treatment plant located in Southeast Spain, including an oxidation ditch, rapid sand filtration, and ultraviolet disinfection. A total of 146.73 L of wastewater samples from influent and effluent were processed, following a density separation methodology, visual classification under a stereomicroscope, and FTIR analysis for polymer identification. Microplastics proved to be 72.41% of total microparticles collected, with a global removal rate of 64.26% after the tertiary treatment and within the average retention for European WWTPs. Three different shapes were identified: i.e., microfiber (79.65%), film (11.26%), and fragment (9.09%), without the identification of microbeads despite the proximity to a plastic compounding factory. Fibers were less efficiently removed (56.16%) than particulate microplastics (90.03%), suggesting that tertiary treatments clearly discriminate between forms, and reporting a daily emission of 1.6 × 10⁷ microplastics to the environment. Year variability in microplastic burden was cushioned at the effluent, reporting a stable performance of the sewage plant. Eight different polymer families were identified, LDPE film being the most abundant form, with 10 different colors and sizes mainly between 1–2 mm. Future efforts should be dedicated to source control, plastic waste management, improvement of legislation, and specific microplastic-targeted treatment units, especially for microfiber removal. Full article

The main aim of this study was a survey of micropollutants in stormwater runoff of Berlin (Germany) and its dependence on land-use types. In a one-year monitoring program, event mean concentrations were measured for a set of 106 parameters, including 85 organic micropollutants (e.g., flame retardants, phthalates, pesticides/biocides, polycyclic aromatic hydrocarbons (PAH)), heavy metals and standard parameters. Monitoring points were selected in five catchments of different urban land-use types, and at one urban river. We detected 77 of the 106 parameters at least once in stormwater runoff of the investigated catchment types. On average, stormwater runoff contained a mix of 24 µg L⁻¹ organic micropollutants and 1.3 mg L⁻¹ heavy metals. For organic micropollutants, concentrations were highest in all catchments for the plasticizer diisodecyl phthalate. Concentrations of all but five parameters showed significant differences among the five land-use types. While major roads were the dominant source of traffic-related substances such as PAH, each of the other land-use types showed the highest concentrations for some substances (e.g., flame retardants in commercial area, pesticides in catchment dominated by one family homes). Comparison with environmental quality standards (EQS) for surface waters shows that 13 micropollutants in stormwater runoff and 8 micropollutants in the receiving river exceeded German quality standards for receiving surface waters during storm events, highlighting the relevance of stormwater inputs for urban surface waters. Full article

A holistic approach to the management of water, energy, food, and the environment is required to both meet the socioeconomic demands of the future as well as sustainable development of these limited resources. The Urmia Lake Basin has faced environmental, social, and economic challenges in recent years, and this situation is likely to worsen under the impacts of climate change. For this study, an adaptability analysis of this region is proposed for the 2040 horizon year. Two models, the water evaluation and planning (WEAP (Stockholm Environmental Institute, Stockholm, Sweden)) and the low emissions analysis platform (LEAP (Stockholm Environmental Institute, Boston, MA, USA)), are integrated to simulate changes in water, energy, food, and the environment over these 20 years. Two climate scenarios and nine policy scenarios are combined to assess sustainable development using a multi-criteria decision analysis (MCDA) approach. Results show that, through pursuing challenging goals in agricultural, potable water, energy, and industrial sectors, sustainable development will be achieved. In this scenario, the Lake Urmia water level will reach its ecological water level in 2040. However, social, technical, and political challenges are considered obstacles to implementing the goals of this scenario. In addition, industry growth and industry structure adjustment have the most impact on sustainable development achievement. Full article

Fluvial floods are one of the primary natural hazards to our society, and the associated flood risk should always be evaluated for present and future conditions. The European Union’s (EU) Floods Directive highlights the importance of flood mapping as a key stage for detecting vulnerable areas, assessing floods’ impacts, and identifying damages and compensation plans. The implementation of the EU Flood Directive in Greece is challenging because of its geophysical and climatic variability and diverse hydrologic and hydraulic conditions. This study addressed this challenge by modeling of design rainfall at the sub-watershed level and subsequent estimation of flood design hydrographs using the Natural Resources Conservation Service (NRCS) Unit Hydrograph Procedure. The HEC-RAS 2D model was used for flood routing, estimation of flood attributes (i.e., water depths and flow velocities), and mapping of inundated areas. The modeling approach was applied at two complex and ungauged representative basins: The Lake Pamvotida basin located in the Epirus Region of the wet Western Greece, and the Pinios River basin located in the Thessaly Region of the drier Central Greece, a basin with a complex dendritic hydrographic system, expanding to more than 1188 river-km. The proposed modeling approach aimed at better estimation and mapping of flood inundation areas including relative uncertainties and providing guidance to professionals and academics. Full article

Seawater desalination is a worldwide concern for the sustainable production of drinking water. In this regard, membrane distillation (MD) has shown the potential for effective brine treatment. However, the lack of appropriate MD membranes limits its industrial expansion since they experience fouling and wetting issues. Therefore, hydrophobic membranes are promising candidates to successfully deal with such phenomena that are typical for commercially available membranes. Here, several graphene/polyvinylidene (PVDF_G) membranes with different graphene loading (0–10 wt%) were prepared through a phase inversion method. After full characterization of the resulting membranes, the surface revealed that the well-dispersed graphene in the polymer matrix (0.33 and 0.5 wt% graphene loading) led to excellent water repellence together with a rough structure, and a large effective surface area. Importantly, antifungal activity tests of films indicated an increase in the inhibition percentage for PVDF_G membranes against the Curvularia sp. fungal strain. However, the antifungal surface properties were found to be the synergistic result of graphene toxicity and surface topography. Full article

Determining natural background levels (NBLs) is a fundamental step in assessing the chemical status of groundwater bodies in the EU, as stipulated by the Water Framework and Groundwater Directives. The major challenges in deriving NBLs for trace metals are understanding the interaction of natural and anthropogenic processes and identifying the boundary between pristine and polluted groundwater. Thus, the purpose of this paper is to present a roadmap guiding the process of method selection for setting meaningful NBLs of trace metals in groundwater. To develop the roadmap, we compared and critically assessed how three methods for excluding polluted sampling points affect the NBLs for As, Cd, Cr, Cu, Ni, and Zn in Danish aquifers. These methods exclude sampling points based on (1) the primary use of the well (or sampling purpose), (2) the dominating anthropogenic pressure in the vicinity of the well, or (3) a combination of pollution indicators (NO₃, pesticides, organic micropollutants). Except for Ni, the NBLs derived from the three methods did not differ significantly, indicating that the data pre-selection based on the primary use of the wells is an important step in assuring the removal of anthropogenically influenced points. However, this pre-selection could limit the data representativity with respect to the different groundwater types. The roadmap (a step-by-step guideline) can be used at the national scale in countries with varying data availability. Full article

The technical and scientific analysis regarding studies of the water surface or groundwater has increasingly taken on a great social impact, which has led to the creation of the term socio-hydrology. Since decision making has a greater weight, considering the social perspective, its study has become more important in the past 20 years. This article aims to carry out a bibliometric analysis related to socio-hydrology using the Scopus database and the application of VOSviewer software for the evaluation of the intellectual structure of socio-hydrology, its conceptual evolution, and its tendencies. The methodology considers (i) search criteria of the research field, (ii) search and document selection, (iii) software and data extraction, and (iv) analysis of results and trends. The results show us the term socio-hydrology as a new scientific discipline that has traces in the Scopus database in the past two decades. However, its application stems from recognising ancestral knowledge alongside other forms of knowledge. Socio-hydrology practice requires participatory models, where the community has a great influence, and for the most part, it guarantees results for the common good. The trend of this topic is growing and open to the criteria of sustainability. Full article

The current global water environment has been seriously damaged. The prediction of water quality parameters can provide effective reference materials for future water conditions and water quality improvement. In order to further improve the accuracy of water quality prediction and the stability and generalization ability of the model, we propose a new comprehensive deep learning water quality prediction algorithm. Firstly, the water quality data are cleaned and pretreated by isolation forest, the Lagrange interpolation method, sliding window average, and principal component analysis (PCA). Then, one-dimensional residual convolutional neural networks (1-DRCNN) and bi-directional gated recurrent units (BiGRU) are used to extract the potential local features among water quality parameters and integrate information before and after time series. Finally, a full connection layer is used to obtain the final prediction results of total nitrogen (TN), total phosphorus (TP), and potassium permanganate index (COD-Mn). Our prediction experiment was carried out according to the actual water quality data of Daheiting Reservoir, Luanxian Bridge, and Jianggezhuang at the three control sections of the Luan River in Tangshan City, Hebei Province, from 5 July 2018 to 26 March 2019. The minimum mean absolute percentage error (MAPE) of this method was 2.4866, and the coefficient of determination (R²) was able to reach 0.9431. The experimental results showed that the model proposed in this paper has higher prediction accuracy and generalization than the existing LSTM, GRU, and BiGRU models. Full article

Water yield is a key ecosystem function index, directly impacting the sustainable development of the basin economy and ecosystem. Climate and land use/land cover (LULC) changes are the main driving factors affecting water yield. In the context of global climate change, assessing the impacts of climate and LULC changes on water yield in the alpine regions of the Qinghai–Tibet Plateau (QTP) is essential for formulating rational management and development strategies for water resources. On the basis of the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, we simulated and analyzed the spatiotemporal variations and the impacts of LULC and climate changes on water yield from 2001 to 2019 in the upstream regions of the Shule River Basin (USRB) on the northeastern margin of the QTP. Three scenarios were designed in the InVEST model to clearly analyze the contributions of climate and LULC changes on the variation of water yield. The first scenario integrated climate and LULC change into the model according to the actual conditions. The second scenario was simulation without LULC change, and the third scenario was without climate change. The results showed that (1) the InVEST model had a good performance in estimating water yield (coefficient of determination (R²) = 0.986; root mean square error (RMSE) = 3.012, p < 0.05); (2) the water yield significantly increased in the temporal scale from 2001 to 2019, especially in the high altitude of the marginal regions (accounting for 32.01%), while the northwest regions significantly decreased and accounted for only 8.39% (p < 0.05); (3) the spatial distribution of water yield increased from the middle low-altitude regions to the marginal high-altitude regions; and (4) through the analysis of the three scenarios, the impact of climate change on water yield was 90.56%, while that of LULC change was only 9.44%. This study reveals that climate warming has a positive impact on water yield, which will provide valuable references for the integrated assessment and management of water resources in the Shule River Basin. Full article

Water is an essential resource that facilitates the existence of human life forms. In recent years, the demand for the consumption of freshwater has substantially increased. Seawater contains a high concentration of salt particles and salinity, making it unfit for consumption and domestic use. Water treatment plants used to treat seawater are less efficient and reliable. Deep learning systems can prove to be efficient and highly accurate in analyzing salt particles in seawater with higher efficiency that can improve the performance of water treatment plants. Therefore, this work classified different concentrations of salt particles in water using convolutional neural networks with the implementation of transfer learning. Salt salinity concentration images were captured using a designed Raspberry Pi based model and these images were further used for training purposes. Moreover, a data augmentation technique was also employed for the state-of-the-art results. Finally, a deep learning neural network was used to classify saline particles of varied concentration range images. The experimental results show that the proposed approach exhibited superior outcomes by achieving an overall accuracy of 90% and f-score of 87% in classifying salt particles. The proposed model was also evaluated using other evaluation metrics such as precision, recall, and specificity, and showed robust results. Full article

Groundwater is the main resource for irrigation and drinking supply in most parts of Syria, as for most Mediterranean countries, however this resource suffers from mismanagement. In the study area (northeast of Mt. Hermon), the lack of information makes water management in this area extremely difficult. Assessing groundwater pollution risk is the most essential issue for water resources management, especially in the regions where complex interaction between climate, geology, geomorphology, hydrogeology, water scarcity and water resource mismanagement exist. This complexity leads to significant complication in determining pollution risk of studied system. In the present work, we adopted an integrative approach to assess groundwater pollution risk in the study area. This methodology is based on the analysis of hydrogeological characteristics of aquifer systems and the available information about socioeconomic context and physiochemical groundwater conditions that might affect this system. This approach allowed us to delineate the groundwater pollution risk map based on the analysis of concerning parameters/indicators. The degree of risk was assessed as the sum and average of rating of these parameters and indicators for each subarea. Typically, very high pollution risk index was identified over the Quaternary/Neogene horizon, i.e., shallow and unconfined aquifer and in the lower part of Jurassic aquifer. In these two parts, the majority of anthropogenic activities are concentrated. Low pollution risk index was found for the outcropping of low permeable Quaternary basalt at the Southern part of the study area. A moderate pollution index was identified for the low/moderate permeability of silt, clay and marly limestone-rich horizons of the major part of Neogene aquifer outside of the intersected zones with Quaternary aquifer and for the Paleogene formations. The spatial analysis shows that about 50% of the study area is characterized as being at very high and high pollution risk index. Hence, the overall natural protective capacity of this area is still poor. This study demonstrates the flexibility of the proposed approach to assess groundwater pollution risk in local complex aquifer system characterized by lack of information and data in order to reduce the risk of future groundwater pollution. Full article

Evapotranspiration (ET) is a key variable in the hydrological cycle and it directly impacts the surface balance and its accurate assessment is essential for a correct water management. ET is difficult to measure, since the existing methods for its direct estimate, such as the weighing lysimeter or the eddy-covariance system, are often expensive and require well-trained research personnel. To overcome this limit, different authors developed experimental models for indirect estimation of ET. However, since the accuracy of ET prediction is crucial from different points of view, the continuous search for more and more precise modeling approaches is encouraged. In light of this, the aim of the present work is to test the efficiency in predicting ET fluxes in a newly introduced physical-based model, named Prospero, which is based on the ability to compute the ET using a multi-layer canopy model, solving the energy balance both for the sunlight and shadow vegetation, extending the recently developed Schymanski and Or method to canopy level. Additionally, Prospero is able to compute the actual ET using a Jarvis-like model. The model is integrated as a component in the hydrological modelling system GEOframe. Its estimates were validated against observed data from five Eddy covariance (EC) sites with different climatic conditions and the same vegetation cover. Then, its performances were compared with those of two already consolidated models, the Priestley–Taylor model and Penman FAO model, using four goodness-of-fit indices. Subsequently a calibration of the three methods has been carried out using LUCA calibration within GEOframe, with the purpose of prediction errors. The results showed that Prospero is more accurate and precise with respect to the other two models, even if no calibrations were performed, with better performances in dry climatic conditions. In addition, Prospero model turned to be the least affected by the calibration procedure and, therefore, it can be effectively also used in a context of data scarcity. Full article

The European Union Water Framework Directive (WFD) encourages water managers to implement active stakeholder involvement to achieve sustainable water management. However, the WFD does not describe in detail how member states should operationalize participation. The need for local experience and local understanding of collaborative governance (co-governance) processes remains. The WaterCoG project evaluated 11 local pilot schemes. Building on the participatory, qualitative evaluation of pilot schemes from Sweden, United Kingdom, Denmark, The Netherlands, and Germany, the authors take a closer look at how co-governance can improve water governance, how water managers can make best use of tools and knowledge, and how they can improve process designs. The results reflect how social learning and successful co-governance are linked. Social learning as a shared understanding of complex ecosystem and water-management issues can be supported with active stakeholder involvement and citizen science. As such, in co-governance processes, stakeholders need technical access to data and knowledge and a shared process memory. This enables them to develop a shared understanding and facilitates bringing together competing interests and finding new solutions. Participatory tools became part of successful processes by building trust and knowledge based on commitment. However, proficient process design and facilitation make these tools more effective. Full article

We analyze how residential water consumption is influenced by the consumption of households belonging to the same social group (peer effect). Analyses are based on household-level data provided by the Brazilian Household Budget Survey and use an innovative strategy that estimates the spatial dependence of water consumption while simultaneously controlling for potential sources of sample selectivity and endogeneity. The estimates of our quantile regression models highlight that, conditional on household characteristics, the greater the household water consumption, the greater the peer effect. In other words, the overconsumption of residential water seems to be influenced mainly by the behavior of social peers. Full article

In this work, the pyrolysis of post-consumer mixed plastic waste (polypropylene (PP), polystyrene (PS) and polyethylene film (PE)) is carried out. The solid product of the pyrolysis is characterized and tested for its use as adsorbent of lead present in aqueous media. The pyrolysis temperature has a great influence on the solid product yield, decreasing when the temperature increases. The highest yield to solid product obtained is from the pyrolysis of film at lower temperature (450 °C), reaching almost 14%. The results of product solid characterization reveal that the carbon, hydrogen and nitrogen content decreases with increasing pyrolysis temperature. Furthermore, both the ash and the volatile content are related to the pyrolysis temperature. The ash content is higher when the pyrolysis temperature is higher, while when the temperature increases, a solid product with lower volatile content is obtained. In respect to specific surface area, a higher pyrolysis temperature improves the properties of the solid product as an adsorbent. The adsorption capacity increases as the pyrolysis temperature increases, with the highest value of 7.91 mg/g for the solid obtained in the pyrolysis at 550 °C. In addition, adsorption capacity increases as the initial concentration of lead rises, reaching a maximum value close to 26 mg/g for an initial concentration of 40 mg/L. The Sips model is the one that best reproduces the experimental results of the adsorption process equilibrium study. Full article

In the Venice Lagoon some of the highest tides in the Mediterranean occur, which have influenced the evolution of the city of Venice and the surrounding lagoon for centuries. The forecast of “high waters” in the lagoon has always been a matter of considerable practical interest. In this study, tide prediction models were developed for the entire lagoon based on Nonlinear Autoregressive Exogenous (NARX) neural networks. The NARX-based model development was performed in two different stages. The first stage was the training and testing of the NARX network, performed on data collected in a given time interval at the tide gauge of Punta della Salute, at the end of Canal Grande. The second stage consisted of a comprehensive validation of the model in the entire Venice Lagoon, with a detailed analysis of data from three measuring stations located in points of the lagoon with different characteristics. Good predictions were achieved regardless of whether the meteorological parameters were considered among input parameters, even with considerable time advance. Furthermore, the forecasting model based on NARX has proved capable of predicting even exceptional high tides. The proposed model could be a useful support tool for the management of the MOSE system, which will protect Venice from high waters. Full article

Inappropriate irrigation conditions and nitrogen application can negatively affect soil carbon–nitrogen content and yield of maize, as well as can lead to underground water pollution and soil degradation. A two year (2018, 2019) field experiment was carried out to determine the effect of irrigation and N, alone and in combination on maize grain yield, grain nitrogen content, soil inorganic N and MBC of one-year double cropping maize (Zea mays L.) in a subtropical region. Split plot design was adopted, with main plots consisting of two water regimes: drip irrigation (drip irrigation to keep soil water content no less than 70% of maximum field capacity) and rainfed (no irrigation during growing period). Split-plot treatments consisted of five nitrogen application levels, including 0 (N0), 150 (N150), 200 (N200), 250 (N250), and 300 kg/ha (N300). The results of two-year field experiment showed that soil irrigation nitrogen interaction had a significant influence on the all measured parameters. In detail, soil NH₄⁺-N and NO₃⁻-N content, total nitrogen (TN), soil organic carbon (SOC) and grain nitrogen contents under the combined treatment of N250 and supplementary irrigation were higher relative to other treatments. Compared with rainfed, maize yield, thousand grains weight (TGW) and harvest index increased by 22.0%, 7.7%, and 15.2% under supplemental irrigation. Yield and TGW N300 were 287 kg/ha and 3.1 g higher than those of N250, and yield and TGW of N250 were 59.4% and 23.1% higher than those of N0, respectively. The yield of spring maize was 24.0% significantly higher than that of autumn maize. Therefore, we suggested that 250 kg/ha nitrogen application fertilizer combined with supplementary irrigation can improve soil fertility and annual maize yield in subtropical one-year double cropping region. Full article

A comprehensive hydrogeological understanding of the deep Upper Jurassic carbonate aquifer, which represents an important geothermal reservoir in the South German Molasse Basin (SGMB), is crucial for improved and sustainable groundwater resource management. Water chemical data and environmental isotope analyses of δD, δ${}^{18}$O and ${}^{87}$Sr/${}^{86}$Sr were obtained from groundwater of 24 deep Upper Jurassic geothermal wells and coupled with a few analyses of noble gases (${}^3$He/${}^4$He, ${}^{40}$Ar/${}^{36}$Ar) and noble gas infiltration temperatures. Hierarchical cluster analysis revealed three major water types and allowed a hydrochemical zoning of the SGMB, while exploratory factor analyses identified the hydrogeological processes affecting the water chemical composition of the thermal water. Water types 1 and 2 are of Na-[Ca]-HCO${}_3$-Cl type, lowly mineralised and have been recharged under meteoric cold climate conditions. Both water types show ${}^{87}$Sr/${}^{86}$Sr signatures, stable water isotopes values and calculated apparent mean residence times, which suggest minor water-rock interaction within a hydraulically active flow system of the Northeastern and Southeastern Central Molasse Basin. This thermal groundwater have been most likely subglacially recharged in the south of the SGMB in close proximity to the Bavarian Alps with a delineated northwards flow direction. Highly mineralised groundwater of water type 3 (Na-Cl-HCO${}_3$ and Na-Cl) occurs in the Eastern Central Molasse Basin. In contrast to water types 1 and 2, this water type shows substantial water-rock interaction with terrestrial sediments and increasing ${}^{40}$Ar/${}^{36}$Ar ratios, which may also imply a hydraulic exchange with fossil formation waters of overlying Tertiary sediments. Full article

Water, energy, and food are essential resources for humanity. The growing shortages of these resources and serious deterioration of river environments are having a big impact on the sustainable development of the economy and society in China. Water, energy, and food support human life and yet coexist in different ways, and therefore it is critical to find a way for all three key elements to be secured in order to support high standards of sustainable development in China. We used the criteria of stability, coordination, and sustainability of symbiotic systems to select 33 indexes that were then used to establish an index system. The weight of index was determined by using the entropy weight method combined with Analytic Hierarchy Process. The fuzzy comprehensive evaluation method was used to calculate the collaborative security index, which was the basis of our evaluation of the collaborative water–energy–food security of China in time and space. The results show that North China and Northwest China are at high water–food–energy security risk, while East, Central, and South China are at moderate risk. With the exception of Southwest China and South China, risk in most parts of the country has risen over the past decades, while it has fallen in Shandong, Henan, Sichuan, and Yunnan provinces. Full article

Water is an essential necessity for human beings; however, South Africa has a long history of inequalities dating back to apartheid politics and legislation which denied access to water to disadvantaged black populations mostly residing in rural areas. Although apartheid has officially ended, whether the lack of access to water by such populations who still cannot afford it exists and aligns with international human rights principles of equality and non-discrimination merits an examination. To redress the injustices of the apartheid regime, the right to have access to sufficient water is entrenched in section 27(1)(b) of the 1996 South African Constitution. In addition to embracing equality and non-discrimination, the Constitution informs other instruments and measures such as free basic water policy and pre-paid meters meant to ensure access to water. However, the plight of these populations persists in post-apartheid South Africa, but it is rarely a subject of academic scrutiny how the notion of affirmative action as grounded in the principles of equality and non-discrimination under human rights law can be deployed as a response. Using a doctrinal research approach, this article argues that the continuing struggle of disadvantaged communities with access to water does not only constitute water apartheid, it negates the human rights principles of equality and non-discrimination. The principle of affirmative action is useful in responding to inadequate access to sufficient water by disadvantaged populations in post-apartheid South Africa. Full article

Although plot-scale erosion experiments are numerous, there are few studies on constructed landforms. This limits the understanding of their long-term stability, which is especially important for planning mined land rehabilitation. The objective of this study was to gain insight into the erosion processes in a 30 × 30 m trial plot on a mine waste rock dump in tropical northern Australia. The relationships between rainfall, runoff and suspended and bedload sediment export were assessed at annual, seasonal, inter-event and intra-event timescales. During a five-year study period, 231 rainfall–runoff–sediment export events were examined. The measured bedload and suspended sediments (mainly represented in nephelometric turbidity units (NTU)) showed the dominance of the wet season and heavy rainfall events. The bedload dominated the total mass, although the annual bedload diminished by approximately 75% over the five years, with greater flow energy required over time to mobilise the same bedload. The suspended load was more sustained, though it also exhibited an exhaustion process, with equal rainfall and runoff volumes and intensities, leading to lower NTU values over time. Intra-event NTU dynamics, including runoff-NTU time lags and hysteretic behaviours, were somewhat random from one event to the next, indicating the influence of the antecedent distribution of mobilisable sediments. The value of the results for supporting predictive modelling is discussed. Full article

An experimental investigation of flexural-gravity waves was performed in the Hamburg Ship Model Basin HSVA ice tank. Physical characteristics of the water-ice system were measured in several locations of the tank with a few sensors deployed in the water and on the ice during the tests. The three-dimensional motion of ice was measured with the optical system Qualisys; water pressure was measured by several pressure sensors mounted on the tank wall, in-plane deformations of the ice and the temperatures of the ice and water were measured by fiber optic sensors; and acoustic emissions were recorded with compressional crystal sensors. The experimental setup and selected results of the tests are discussed in this paper. Viscous-elastic model (Burgers material) is adopted to describe the dispersion and attenuation of waves propagating below the ice. The elastic modulus and the coefficient of viscosity are calculated using the experimental data. The results of the measurements demonstrated the dependence of wave characteristics from the variability of ice properties during the experiment caused by the brine drainage. We showed that the cyclic motion of the ice along the tank, imitating ice drift, and the generation of under ice turbulence cause an increase of wave damping. Recorded acoustic emissions demonstrated cyclic microcracking occurring with wave frequencies and accompanying bending deformations of the ice. This explains the viscous and anelastic rheology of the model ice. Full article

Pakistan is among the countries that have already crossed the water scarcity line, and the situation is worsened due to the recent pandemic. This is because the major budget of the country is shifted to primary healthcare activities from other development projects that included water treatment and transportation infrastructure. Consequently, water-borne diseases have increased drastically in the past few months. Therefore, there is a dire need to address this issue on a priority basis to ameliorate the worsening situation. One possible solution is to shift the focus/load from mega-projects that require a plethora of resources, money, and time to small domestic-scale systems for water treatment. For this purpose, domestic-scale solar stills are designed, fabricated, and tested in one of the harshest climatic condition areas of Pakistan, Rahim Yar Khan. A comprehensive overview of the regional climatology, including wind speed, solar potential, and ambient temperature is presented for the whole year. The analysis shows that the proposed system can adequately resolve the drinking water problems of deprived areas of Pakistan. The average water productivity of 1.5 L/d/m² is achieved with a total investment of PKR 3000 (<$20). This real site testing data will serve as a guideline for similar system design in other arid areas globally. Full article

In drought years, most residents fail to improve water use efficiency due to residential water supply normally being prioritized in many regions, which makes other low-priority industrial water users suffer more from water shortage. This paper proposes a Pricing Strategy for Residential Water (PSRW), a water tariff that changes on annual time scale, based on the scarcity value of water resources, aiming to promote residential water conservation and reallocate water resources across the residential and industrial sectors during droughts. An optimization model to maximize the total benefit of residents and industrial sectors is introduced based on marginal benefit and price elasticity. The water shortage of industrial sectors is used to reflect the scarcity of water resources, and the lowest water supply standard for households and the maximum proportion of household water fee expenditure (HWFE) to household disposable income (HDI) are used to ensure the residents’ acceptability to price raising. It shows an “S-type” relationship between the optimal price raising coefficient and industrial water shortage, and two turning points are found in the curve, which are the starting and stopping points of price raising. The appearance of starting point depends on the non-negative net benefit, and the stopping point is affected by the factors that represent the residents’ acceptability to price raising. The application to Tianjin, a city in northern China with the rapid growth of population and economy but scarce water resources, shows PSRW is a potential means to improve water efficiency and optimize water resource allocation in water scarcity situations. Full article

Multi-objective evolutionary algorithms (MOEAs) are widely used to optimize multi-purpose reservoir operations. Considering that most outcomes of MOEAs are Pareto optimal sets with a large number of incomparable solutions, it is not a trivial task for decision-makers (DMs) to select a compromise solution for application purposes. Due to the increasing popularity of data-driven decision-making, we introduce a clustering-based decision-making method into the multi-objective reservoir operation optimization problem. Traditionally, solution selection has been conducted based on trade-off ranking in objective space, and solution characteristics in decision space have been ignored. In our work, reservoir operation processes were innovatively clustered into groups with unique properties in decision space, and the trade-off surfaces were analyzed via clustering in objective space. To attain a suitable performance, a new similarity measure, referred to as the Mei–Wang fluctuation similarity measure (MWFSM), was tailored to reservoir operation processes. This method describes time series in terms of both their shape and quantitative variation. Then, a compromise solution was selected via the joint use of two clustering results. A case study of the Three Gorges cascade reservoirs system under small and medium floods was investigated to verify the applicability of the proposed method. The results revealed that the MWFSM effectively distinguishes reservoir operation processes. Two more operation patterns with similar positions but different shapes were identified via MWFSM when compared with Euclidean distance and the dynamic time warping method. Furthermore, the proposed method decreased the selection range from the whole Pareto optimal set to a set containing relatively few solutions. Finally, a compromise solution was selected. Full article

Small streams in urbanized rural areas receive loads of P from various, often episodic, sources. This paper addresses, through a tracer test with ${}^{32}$P, retention and transport of a pulse input of phosphorus in a 2.6 km long stretch of a channelized second-order lowland stream. Tritiated water was introduced alongside the ${}^{32}$P-labelled ortophosphate in order to isolate the influence of the hydrodynamic factors on P behavior. Tracer concentrations in unfiltered water samples were measured by liquid scintillation counting. Four in-stream and five hyporheic breakthrough curves were collected at four points along the stream, two of which encompass a beaver dam impoundment. The overall retention efficiency of ${}^{32}$P along the studied reach was 46%. The transient storage transport model OTIS-P provided reasonable fits for in-stream breakthrough curves (BTCs) but failed at reproducing the hyporheic BTCs. The overall small effect of transient storage on solute transport was higher in the stretch with a more pronounced surface storage. Transient storage and phosphorus retention were not enhanced in the beaver dam impoundment. Full article

Intensity-duration-frequency (IDF) relationships are traditional tools in water infrastructure planning and design. IDFs are developed under a stationarity assumption which may not be realistic, neither in the present nor in the future, under a changing climatic condition. This paper introduces a framework for generating non-stationary IDFs under climate change, assuming that probability of occurrence of quantiles changes over time. Using Extreme Value Theory, eight trend combinations in Generalized Extreme Value (GEV) parameters using time as covariate are compared with a stationary GEV, to identify the best alternative. Additionally, a modified Equidistance Quantile Matching (EQM_NS) method is implemented to develop IDFs for future conditions, introducing non-stationarity where justified, based on the Global Climate Models (GCM). The methodology is applied for Moncton and Shearwater gauges in Northeast Canada. From the results, it is observed that EQM_NS is able to capture the trends in the present and to translate them to estimated future rainfall intensities. Comparison of present and future IDFs strongly suggest that return period can be reduced by more than 50 years in the estimates of future rainfall intensities (e.g., historical 100-yr return period extreme rainfall may have frequency smaller than 50-yr under future conditions), raising attention to emerging risks to water infrastructure systems. Full article

Shifts in winter temperature and precipitation patterns can profoundly affect snow accumulation and melt regimes. These shifts have varying impacts on local to large-scale hydro-ecological systems and freshwater distribution, especially in cold regions with high hydroclimatic heterogeneity. We evaluate winter climate changes in the six ecozones (Mountains, Foothills, Prairie, Parkland, Boreal, and Taiga) in Alberta, Canada, and identify regions of elevated susceptibility to change. Evaluation of historic trends and future changes in winter climate use high-resolution (~10 km) gridded data for 1950–2017 and projections for the 2050s (2041–2070) and 2080s (2071–2100) under medium (RCP 4.5) and high (RCP 8.5) emissions scenarios. Results indicate continued declines in winter duration and earlier onset of spring above-freezing temperatures from historic through future periods, with greater changes in Prairie and Mountain ecozones, and extremely short or nonexistent winter durations in future climatologies. Decreases in November–April precipitation and a shift from snow to rain dominate the historic period. Future scenarios suggest winter precipitation increases are expected to predominantly fall as rain. Additionally, shifts in precipitation distributions are likely to lead to historically-rare, high-precipitation extreme events becoming more common. This study increases our understanding of historic trends and projected future change effects on winter snowpack-related climate and can be used inform adaptive water resource management strategies. Full article

Water resources face an unparalleled confluence of pressures, with agriculture and urban growth as the most relevant human-related stressors. In this context, methodologies using a Nexus framework seem to be suitable to address these challenges. However, the urban sector has been commonly ignored in the Nexus literature. We propose a Nexus framework approach, considering the economic dimensions of the interdependencies and interconnections among agriculture (food production) and the urban sector as water users within a common basin. Then, we assess the responses of both sectors to climatic and demographic stressors. In this setting, the urban sector is represented through an economic water demand at the household level, from which economic welfare is derived. Our results show that the Nexus components here considered (food, water, and welfare) will be negatively affected under the simulated scenarios. However, when these components are decomposed to their particular elements, we found that the less water-intensive sector—the urban sector—will be better off since food production will leave significant amounts of water available. Moreover, when addressing uncertainty related to climate-induced shocks, we could identify the basin resilience threshold. Our approach shows the compatibilities and divergences between food production and the urban sector under the Nexus framework. Full article