Water, Volume 14, Issue 18 (September-2 2022) – 167 articles

Snowiness and avalanche activity are very important natural characteristics of mountain areas. They have a great influence on the possibility of areas’ development, especially regarding winter recreation. This article considers the interannual variability of snowiness and avalanche activity in the Ile Alatau Ridge (Northern Tien Shan), which belongs to the areas with a continental snow climate. The sum of winter precipitation and snow depth are used as snowiness indices, and the indices of avalanche activity are the total avalanche volume, maximum avalanche volume and number of avalanches. The work uses archival data for the period from 1966 to 2022. Interannual variability of snowiness and avalanche activity indices and long-term temporal trends were assessed, correlation between these indices was studied, and extreme values with different return periods were calculated. The relationship between years with a high snowiness and years with a high avalanche activity, as well as years with a high avalanche activity and years with a large number of avalanche victims and high avalanche damage has been studied. Similar studies have not been previously carried out for the areas with a continental snow climate. Snowiness indices have weak, non-significant, increasing temporal trends. The total avalanche volume has a non-significant decreasing temporal trend, and the maximum avalanche volume has a significant decreasing one. The number of avalanches has a significant increasing temporal trend. This study could be relevant for understanding the features of temporal variability of snowiness and avalanche activity in the mountainous regions with a continental snow climate. Full article

Water temperature is an important indicator of water quality for surface water resources because it impacts solubility of dissolved gases in water, affects metabolic rates of aquatic inhabitants, such as fish and harmful algal blooms (HABs), and determines the fate of water resident biogeochemical nutrients. Furthermore, global warming is causing a widespread rise in temperature levels in water sources on a global scale, threatening clean drinking water supplies. Therefore, it is key to increase the frequency of spatio-monitoring for surface water temperature (SWT). However, there is a lack of comprehensive SWT monitoring datasets because current methods for monitoring SWT are costly, time consuming, and not standardized. The research objective of this study was to estimate SWT using data from the Landsat-8 (L8) and Sentinel-3 (S3) satellites. To do this, we used machine learning techniques, such as Support Vector Regression (SVR), Gaussian Process Regression (GPR), simple neural network (ANN), and deep learning techniques (Long Short Term Memory, LSTM, and Convolutional Long Short Term Memory, 1D ConvLSTM). Using deep and machine learning techniques to regress satellite data to estimate SWT presents a number of challenges, including prediction uncertainty, over- or under-estimation of measured values, and significant variation in the final estimated data. The performance of the L8 ConvLSTM model was superior to all other methods (R² of 0.93 RMSE of 0.16 °C, and bias of 0.01 °C). The factors that had a significant effect on the model’s accuracy performance were identified and quantified using a two-factor analysis of variance (ANOVA) analysis. The results demonstrate that the main effects and interaction of the type of machine/deep learning (ML/DL) model and the type of satellite have statistically significant effects on the performances of the different models. The test statistics are as follows: (satellite type main effect p *** ≤ 0.05, F_test = 15.4478), (type of ML/DL main effect p *** ≤ 0.05, F_test = 17.4607) and (interaction, satellite type × type of ML/DL p ** ≤ 0.05, F_test = 3.5325), respectively. The models were successfully deployed to enable satellite remote sensing monitoring of SWT for the reservoir, which will help to resolve the limitations of the conventional sampling and laboratory techniques. Full article

Abundance–Biomass Comparison (ABC) models, first described for marine benthic macrofauna, have been applied successfully to other marine and terrestrial/freshwater fauna but never to ecotonal communities. In particular, to our knowledge, ABC models have not been applied to hyporheic communities. This study represents the first application of ABC models to hyporheic assemblages. We aimed at testing the effectiveness of ABC models in describing the perturbation of hyporheic communities subjected to an existing/known disturbance. To this end, we applied the models to the hyporheic community of an Apennine creek, where the hyporheic waters of the upstream stretch were uncontaminated, whereas those of the downstream stretch were contaminated by ammonium. We also tested separated models for the summer and winter periods to account for potential variability due to season. ABC models provided a satisfactory description of the hyporheic community changes due to ammonium by showing the abundance dominance curve overlying that of the biomass in the downstream stretch contrarily to what was observed in the upstream stretch. However, ABC models did not highlight any significant seasonal effects. Our results showed that ABC models have the potential to be used as assessment tools for ecological quality of hyporheic zones in temperate regions. Full article

Seawater intrusion is expected to cause a shortage of freshwater resources in coastal areas which will hinder regional economic and social development. The consequences of global climate change include rising sea levels, which also affect the results of the predictions of seawater intrusion that are based on simulations. It is thus important to examine the impact of the randomness in the rise in sea levels on the uncertainty in the results of numerical simulations that are used to predict seawater intrusion. Deep learning has lately emerged as a popular area of research that has been used to establish surrogate models in this context. In this study, the authors have used deep learning to determine the complex and nonlinear mapping relationship between the inputs and outputs of a three-dimensional variable-density numerical model of seawater intrusion in the case of a limited number of training samples, wherein, this has improved the accuracy of the approximation of the surrogate models. We used the rise in sea level as a random variable, and then applied the Monte Carlo method to analyze the influence of randomness on the uncertainty in the results of the numerical predictions of seawater intrusion. Statistical analyses and interval estimations of the Cl⁻ concentration and the area of seawater intrusion were conducted at typical observation wells. The work that is here provides a reliable reference for decision making in the area. Full article

Since the UN Water Conference in 1977, international debates have centered on global water scarcity and achieving sustainable development. In 1995, Morocco introduced a water policy to strengthen the country’s socio-economic development through irrigated agriculture, while ensuring the long-term sustainability of water resources through integrated water resource management (IWRM). Empirical research, however, reveals decreasing groundwater levels and increasing inequalities around water access. The purpose of this article is to shed light on the challenges this policy provokes for achieving sustainable development, the limitations it faces to implement IWRM, and provide insights on how the policy is linked to the increased pressure on water resources as reported in the literature. We conducted a content analysis of ten key water policy documents and thirty-seven in-depth semi-structured interviews undertaken between 2020 and 2021 with governmental actors and inhabitants of the Middle Draa Valley (south Morocco). We found that sustainability and social-inequality problems unintendedly triggered by the policy were linked to three factors: the use of a disciplinary approach for policy formulation and its limitations to encompass the complexity of the water-related problems, the compartmentalization of government sectors hindering the development of sound solutions to water-related problems, and the neglect of social, economic, and political factors affecting actual access to water. Full article

In the last two decades of the 20th century, irrigation in Andalusia experienced a historic expansion as a result of the transfer of political powers from the State to regional authorities and, thanks to its application in Andalusia, to pass, among other measures, an agrarian reform bill and the subsequent development of new irrigation infrastructures. Against this background, our objective was to determine the role of the body responsible for implementing agrarian reform, i.e., the Institute for Agrarian Reform (Instituto Andaluz de Reforma Agraria, IARA), by converting drylands into irrigation lands, with a special focus on one of the region’s most vibrant agro-economically transformed areas: the irrigable area of the River Chanza (the west coast of the province of Huelva). To conduct the study, we have applied the historical method and content analysis to technical, legal and agro-statistical documentation from the entire active period of the IARA (1984–2011). The results highlight the leading role played by the IARA in extending irrigation land in agrarian-reform priority areas, as well as in developing irrigation infrastructures in the areas that the State defined as strategic in Andalusia, such as the 17,200 hectares of irrigated land of the Chanza Irrigation Project. We conclude that the radical agro-productive transformation of the coast of Huelva in recent decades is mainly due to the availability of water for irrigation, which the IARA was primarily responsible for planning and executing. Full article

This study aims to analyze the actors and institutions for public water supply governance in armed conflict areas of Rakhine State, Myanmar. Using Stakeholder Salience Theory and Institutional Analysis of data collected from four participatory workshops and interviews with 160 water stakeholders from the four townships in Rakhine State, the findings revealed that although the water supply system is managed and governed by the state water authorities with the involvement of many administrative, political, and sectoral technical agencies and organizations, the non-formal community organizations such as ethnic armed military and religious institutions also have a strong interest in water supply and are considered dangerous actors in the water supply governance process. Diverse water actors held different perspectives and perceptions of water supply quality and quantity because of their different power holdings and political and economic interests. The state actors seemed biased on their positive performance, demonstrating their satisfaction with the current water supply governance, while community, private sectors, and household water users instead showed their dissatisfaction with the quality and quantity of the current water supply system, but they stayed neutral about the water supply governance performance. The research showed the complexity and dynamics of water actors’ powers and interests in armed conflict areas. In addition, there is a lack of socio-technical and financial capacity for the investment and maintenance of water distribution and collection infrastructure and facility, as well as water quality and quantity monitoring and evaluation. The study appeals to the development and peacebuilding organizations working in conflict areas to promote adaptive governance for community learning and adaptation to social-political and environmental change over time. Full article

Nutrients (nitrogen and phosphorus) are among the water quality parameters that cannot be easily removed from wastewater. Unfortunately, the excessive accumulation of nutrients in water can lead to numerous health issues for humans and the environment in general (including aquatic life). This study looked into the potential use of polymeric nanofiltration membranes to remove total phosphorus, ammonia, nitrate, and nitrite from poultry slaughterhouse wastewater. The wastewater samples were subjected to three different treatment systems determined by pore sizes (0.4, 0.6, and 0.8 nm) as well as an integrated system composed of ultrafiltration and nanofiltration as the main units. The results of the study showed that pore size can significantly affect a nanofiltration system’s overall performance for removing nutrients from poultry slaughterhouse wastewater. The phenomenon was supported by the analysis of variance (ANOVA) results, which showed that the treated effluent’s concentrations of the investigated water quality parameters at different pore sizes produced p-values that were less than 0.01 (statistically significant). According to the results of the removal efficiency analysis, the combination of ammonia and a 0.8 nm pore size demonstrated the lowest removal efficiency, with a removal rate of around 54.57%. However, the combination of nitrate and a 0.4 nm pore size showed the best removal efficiency of about 90.5%. On the other hand, the integrated treatment was observed to be highly effective in the removal of the investigated parameters with a removal efficiency ranging from 97.8 to 99.71%. The study’s findings offer useful information about the potential use of nanofiltration treatment systems for wastewater from poultry slaughterhouses. Full article

Water scarcity has become a major impediment to economic development, and a scientifically sound water allocation plan is essential to alleviate water scarcity. An opportunity constraint approach is introduced to optimise the uncertainty of the minimum regional development level under five hydrological scenarios, and an interval-fuzzy two-stage chance-constraint model (IFTSC) is constructed to improve the reliability of the model results. The correlation of each stochastic parameter in the IFTSC model with the water allocation results and the economic benefits of the Tingjiang River basin is analysed by the Pearson correlation coefficient method. Simulation results from the IFTSC model show a downward trend in overall water scarcity and an upward trend in overall economic benefits in the Tingjiang River basin. Taking the dry water scenario as an example, the water shortage in the industrial sector decreases by 9.7%, and the overall economic benefits of the Tingjiang River basin increase by 41.58 × 108 CNY. The results of the correlation analysis based on Pearson’s correlation coefficient show that water allocation is strongly positively correlated with variables such as water price and regional minimum development requirements, and economic efficiency is strongly positively correlated with unit scale output value and losses caused by water shortage. This paper provides constructive suggestions and guiding directions for the rational allocation of water resources in the Tingjiang River basin through a detailed analysis of the results and identification of the main stochastic parameters in the water allocation process. Full article

Climate change, urbanization, and population growth, particularly in urban areas such as Acapulco, Mexico, put pressure on water availability, where although surrounded by water, the inhabitants lack enough good-quality water, especially in the rainy season. In addition, water scarcity, socioeconomic factors, and infrastructure problems limit the satisfaction of water demand in this context, e.g., operational issues in the water treatment plants and problems in the distribution network caused by hurricanes. The objectives of this research were: (i) to determine the rainwater quality in Acapulco, Mexico; (ii) to propose a domestic water efficiency retrofit (WER) design implementing a rainwater harvesting system (RWHS); and (iii) to determine the RWHS efficiency in terms of economic savings, considering rainwater’s social acceptance for domestic consumptive uses. The WER design was developed in an SFH in Acapulco, Mexico. The RWHS catchment surface area was 29 m². The device comprises a first-rain separator (20 L) and a storage tank (1200 L). The rainwater harvesting potential (RWHP) was evaluated during the 2020 and 2021 rainy seasons, whereas the harvested rainwater quality (HRWQ) was analyzed in samples from 2021. Alkalinity, pH, electrical conductivity, total dissolved solids, chlorides, nitrates, sulfates, and heavy metals and potentially toxic metalloids were analyzed. Additionally, 168 surveys were applied to SFH owners to evaluate WER acceptance. Results showed that the RWHP was ca. 44 and 21 L/m² in 2020 and 2021, respectively. All the rainwater quality parameters met the World Health Organization guidelines for consumptive uses except for drinking water. The perception study showed a 95% willingness to adopt the WER. Due to the RWHP and the HRWQ, the WER of SFHs is a promising solution to address Acapulco hydric stress under the nature-based solutions approach. Full article

Future climate projections and their uncertainties affect many aspects of the world, so reliable assessments are essential for policymakers who need to prepare mitigation measures in the context of climate change. In this study, we examined the projected future climate and estimated uncertainty for South Korea using results from the global climate model (GCM), updated from the sixth phase of the coupled model intercomparison project (CMIP6); we then compared the differences in outcome between the fifth and sixth phases of the CMIP (CMIP5 and CMIP6). Future projections were estimated as the averaged climatological mean (denoted as $\overline{CM}$) for the four proposed hydrological indicators. Model uncertainty (UEMI) and stochastic uncertainty (USTO) were quantified as the range of ensembles of the climatological mean, while the emission uncertainty (UEMI) was estimated as the difference between the $\overline{CM}$ values of two emission scenarios. The following are the key findings of our study: (1) using an ensemble of multiple GCMs is recommended over using individual GCMs, and models in CMIP6 performed better for reproducing climate during the control period than models in the CMIP5; (2) the $\overline{CM}$ values in the CMIP6 increased for future periods, especially toward the end of this century, increasing mean temperature (meanTa) by approximately 5 °C, total precipitation (totPr), and daily maximum precipitation (maxDa) by about 20%, and these values were higher than those of the CMIP5; (3) the UGCM, USTO, and UEMI values increased for future periods in most of the indices; (4) the UGCM (for meanTa, totPr, and maxDa) and USTO (for totPr and maxDa) magnitudes in the CMIP6 were higher than those in the CMIP5, while the UEMI values between the two CMIPs were similar for all of the indices; (5) the UGCM was the major source of the largest uncertainty for meanTa, the USTO had a significant impact on future projections of totPr and maxDa, especially in the summer, and the UEMI became the dominant source of uncertainty for projecting the future meanTa, especially in the period farthest from the present. These results should provide useful information for studies that quantify future climate-induced hydrological impacts. Full article

Groundwater (GW) in the Mississippi Delta has some of the highest phosphorus (P) concentrations measured in the U.S. Chemical data collected from GW and surface water (SW) sites were compared to understand factors affecting P concentrations. Spatial instability in Delta GWs indicates that P sources vary. High P measurements in shallow wells near rivers, in shallow nested wells compared to deeper nested wells, and P fluctuations in wells over time suggest that the land surface may be a greater source of P in shallow groundwater than natural geological deposits. Widespread reducing conditions in shallow GW, long-term P applications to the land surface, and shallow wells being proximal to streams are possible covarying explanatory variables. Potential SW to GW pathways of P include leaching and preferential flow paths; however, GW interactions with SW via irrigation, although unnatural, can result in P deposition on soils and later transport to SW or GW. GW tracer data indicate that irrigation return flows can exceed natural baseflow discharge to some streams in late summer. Studies are needed to confirm the degree that P is mobilized from soils and bed sediment to shallow GW and to determine how declines in GW levels resulting from irrigation affect ecological services in SW. Full article

This paper summarizes studies undertaken at a water treatment plant in Skawina (WTP Skawina) where the disinfection process was modified by introducing a mobile ozonation system. The application of a small-size, fully-automated ozonation installation only slightly complicates the water treatment process, without the need to redesign the water treatment line, and with relatively low investment costs. The aim of this study was to analyze whether the change of the disinfection method affects the final water quality. The investigated water samples were treated in the mobile ozonation system using a disinfection process with only sodium hypochlorite. Treated water was of excellent quality, and seasonal variations in raw water parameters (variable organic matter contents) did not result in elevated trihalomethanes (THM) and bromate concentrations. Despite the trace amounts of bromides in the water prior to treatment, the water in the municipal drinking water system did not contain determinable amounts of bromates. The bromine concentrations in the treated water supplied to the water distribution system were higher than in raw water, which could be attributable to the presence of bromine as a contaminant in sodium hypochlorite (the disinfection agent). Water quality tests carried out by the water treatment plant (WTP) and by the State Sanitary Inspectorate after the modification of the process line confirmed the high quality of water in the distribution network after the change of disinfection method. Full article

Monitoring vegetation growth and exploring the driving force behind it is very important for the study of global climate change and ecological environmental protection. Based on Normalized Difference Vegetation Index (NDVI) data from Moderate-Resolution Imaging Spectroradiometer (MODIS), meteorological and nighttime lights data from 2001 to 2020, this study uses the Theil–Sen slope test, Mann–Kendall significance test, Rescaled Range Analysis and partial correlation analysis to investigate the evolution of NDVI in the Minjiang River Basin, China, from three aspects: the spatial-temporal variation characteristics and future trend prediction of NDVI, the variation of climate and human activities in the basin, and the influences of different driving forces on NDVI. The results show that the average NDVI in the growing season was 0.60 in the Minjiang River Basin in the past twenty years, with a growth rate of 0.002/a. The area with high NDVI growth accounts for 66.02%, mainly distributed in the southeast, the central and the northern low-altitude areas of the basin. Combined with the Hurst index, the NDVI in the Minjiang River Basin exhibits an anti-sustainable tendency, with 63.22% of the area changing from improvement to degradation in the future. Meanwhile, the spatial differentiation of NDVI in the Minjiang River Basin is mainly affected by topography and climate factors, followed by human activities. This study not only provides scientific guidelines for the vegetation restoration, soil and water conservation and sustainable development of the Minjiang River Basin, but also provides a scientific basis for making informed decisions on ecological protection under the impacts of climate change and human activities. Full article

The depletion of freshwater supply is occurring at a faster rate than it is being replenished. The agriculture sector is the largest consumer of freshwater for irrigation and production-related processes. The use of reclaimed municipal water for the irrigation of crops offers a sustainable alternative solution for reducing the dependence of agriculture on freshwater. However, the long-term and continuous use of reclaimed water may contribute to soil salinity and sodicity limitations in agriculture production. The chemical and microbial properties of three different soil textures (all Alluvial soil with 60% clay: pH 8.6; 30% clay: pH 8.2; and 20% clay: pH 7.9) were evaluated in a vineyard irrigated using reclaimed water (126 mg/L Na⁺, 154 mg/L Cl⁻, 7.6 water pH, and 1.2 dS/m EC_w). The results indicate that the reclaimed irrigation water significantly (p < 0.05) increased the pH (by 0.4 to 18%), nitrate-N (over 100%), electrical conductivity (EC) (over 100%), and sodium absorption ratio (SAR) in these arid soils. A significant decline in microbial respiration (48 to 80%) was also documented in the three different soil textures that received reclaimed water. Although using reclaimed water for crop irrigation may be a substitute for using limited freshwater resources and offer a partial solution to increasing water security for wine grape production, the development of innovative technologies is needed for the long-term use of reclaimed water to counter its undesirable effects on soil quality. Full article

Insufficient understanding of the microbial communities and associated microbial processes in geological reservoirs hinders the utilization of this rich data source for improved resource management. In this study, along with four interwell tracer tests at a 1478-m deep fractured crystalline-rock aquifer, we analyzed the microbial communities in the injected and produced water by high-throughput sequencing. The microbial community similarities across boreholes during an interwell flow scenario frequently encountered in reservoir development was explored. Despite the significant tracer recoveries (~30%) in all tracer tests and the cumulatively >100,000 L of exogenous water (carrying exogenous microbes) injected into the 10-m-scale reservoir, the overall structure of produced-fluid microbiome did not increasingly resemble that of the injectate. However, producers with better connectivity with the injector (based on tracer test results) did have more amplicon sequence variants (ASVs) that overlapped with those in the injectate. We identified possible drivers behind our observations and verified the practicality of repeated microbial sampling in the context of reservoir characterization and long-term monitoring. We highlight that injector-producer microbial profiling could provide insights on the relative connectivities across different producers with a given injector, and that the associated logistical needs may be comparable or even less than that of classic tracer tests. Full article

This study presents a low-carbon decision-making algorithm for water-spot tourists, based on the k-NN spatial-accessibility optimization model, to address the problems of water-spot tourism spatial decision-making. The attributes of scenic water spots previously visited by the tourists were knowledge-mined, to ascertain the tourists’ interest-tendencies. A scenic water-spot classification model was constructed, to classify scenic water spots in tourist cities. Then, a scenic water spot spatial-accessibility optimization model was set up, to sequence the scenic spots. Based on the tourists’ interest-tendencies, and the spatial accessibility of the scenic water spots, a spatial-decision algorithm was constructed for water-spot tourists, to make decisions for the tourists, in regard to the tour routes with optimal accessibility and lowest cost. An experiment was performed, in which the tourist city of Leshan was chosen as the research object. The scenic water spots were classified, and the spatial accessibility for each scenic spot was calculated; then, the optimal tour routes with optimal spatial accessibility and the lowest cost were output. The experiment verified that the tour routes that were output via the proposed algorithm had stronger spatial accessibility, and cost less than the sub-optimal ones, and were thus more environmentally friendly. Full article

Dingxi City is located in the upper reaches of the Yellow River Basin, at the intersection between the Loess Plateau and West Qinling Mountains. The water and soil conservation function of Dingxi City is very important and have become key constraining factors for economic and social development. Due to the fragmented terrain and landscape patches, high spatial accuracy in the assessment of water and soil conservation is required for proper management. In this study, we introduced an index system for the evaluation of soil and water conservation functions, including various influencing factors. The results showed that area percentages of the five levels (lower, low, medium, high, and higher) in soil conservation were 6.24, 6.25, 23.49, 30.95, and 33.07, respectively, and the areas with higher soil conservation were mainly concentrated in the hilly and gully areas of the Loess Plateau with low vegetation coverage. The percentages of water conservation in the five levels (lower, low, medium, high, and higher) were 40.49, 21.78, 16.66, 7.9, and 13.11, respectively, and the areas with higher water conservation were concentrated in Min County and Zhang County, with the most abundant precipitation and highest vegetation coverage. In addition, functional areas of soil and water conservation had obvious spatial heterogeneity. Among them, the proportion of high-grade functional areas for soil conservation decreased with an increase in precipitation, whereas a high proportion of high-grade functional areas for water conservation was concentrated in areas with precipitation of more than 600 mm. The conflict between agricultural production and ecological protection of soil and water conservation is prominent, and areas with serious conflict are concentrated in the central and northern areas of Dingxi City. Based on this, we suggest a spatial layout guidance for agricultural production and ecological protection, providing a scientific basis for decision-making that supports ecological protection and high-quality sustainable development in Dingxi City. Full article

Quantitative information on regional cropland runoff is important for sustainable agricultural water quantity and quality management. This study combined the Soil Conservation Service Curve Number (SCS-CN) method and geostatistical approaches to quantify long-term (1990–2013) changes and regional spatial variations of cropland runoff in China. Estimated CN values from 17 cropland study sites across China showed reasonable agreement with default values from the National Engineering Handbook (R² = 0.76, n = 17). Among four commonly used geostatistical interpolation methods, the inverse distance weighting (IDW) method achieved the highest accuracy (R² = 0.67, n = 209) for prediction of cropland runoff. Using default CN values and the IDW method, estimated national annual cropland runoff volume and runoff depth in 1990–2013 were 253 ± 25 km³ yr⁻¹ and 182 ± 15 mm yr⁻¹, respectively. Estimated cropland runoff depth gradually increased from the drier northwest inland region to the wetter southeast coastal region (range: 2–1375 mm yr⁻¹). Regionally, eastern, central and southern China accounted for 39% of the cultivated area and 53% of the irrigated land area and contributed to 68% of the national cropland runoff volume. In contrast, northwestern, northern, southwestern and northeastern China accounted for 61% of the cultivated area and 47% of the irrigated land area and contributed to 32% of the runoff volume. Rainfall was the main source (72%) of cropland runoff for the entire nation, while irrigation became the main source of cropland runoff in drier regions (northwestern and southwestern China). Over the 24-year study period, estimated cropland runoff depth showed no significant trends, whereas cropland runoff volume and irrigation-contributed percentages decreased by 7% and 35%, respectively, owing to implementation of water-saving irrigation technologies. To reduce excessive runoff and increase water utilization efficiencies, regionally specific water management strategies should be further promoted. As the first long-term national estimate of cropland runoff in China, this study provides a simple framework for estimating regional cropland runoff depth and volume, providing critical information for guiding developments of management practices to mitigate agricultural nonpoint source pollution, soil erosion and water scarcity. Full article

In this study, the main elements that can make up a Natural Treatment System for Wastewater (NTSW), its most important parameters and properties of operation and design, have been analyzed, as well as the environmental problems derived from the generation of large amounts of slurry. The objective of this paper is to propose a methodology to improve the operation of these systems, associated with small and medium-sized livestock farms, in insular and isolated systems such as the Canary Islands. An Integrated and Resilient System (IRS) for monitoring and measuring operational variables quasi-continuous and in situ is proposed. Low-cost technology and open source hardware are employed, as well as application of the IoT (Internet of Things) strategies to share and analyze the information collected in the cloud. In view of the high degree of resilience and the simplicity of this type of technology, as well as its low cost, it is concluded that it is feasible to create a measurement system with these characteristics that can be used for NTSW parameterization, and other purposes. Satisfactory results were obtained for several parameters (ambient temperature, relative humidity, UV radiation, atmospheric pressure). It is presented as a novel proposal based mainly on low-cost technology and free software with which to improve the NTSW operation process. Full article

Much of our understanding of factors influencing stream chemistry comes from studies of montane forests, whereas far less work has focused on streams of coastal areas that integrate a homogeneous, flat topography and interactions with the bodies of water into which they drain, especially involving tidal fluxes. Fewer still do so in the context of an urban interface, especially that of a college campus. This study assessed the water quality of Thompson Bayou, a freshwater stream entering the University of West Florida campus in a wetland after flowing through the urban property with impacted water quality. We measured temperature, pH, dissolved O₂ (DO), and specific conductivity (SC) for one year at eight sites along Thompson Bayou from campus to the Escambia River. All variables, except temperature, varied spatially, with consistent increases in DO and SC toward the river of 10% and 75%, respectively. Variables exhibited temporal patterns of significant seasonal variation, especially temperature, increasing from a January minimum of 14 °C to a summer maximum of 28 °C. These results suggest that, in general, the biogeochemistry of coastal streams such as Thompson Bayou can be influenced by numerous factors, including (1) wetland processes, (2) interactions of the stream channel with forested uplands, and (3) tidal fluxes. Full article

Various business models for fecal sludge emptying and transport have been developed to address challenges and their advantages have been documented; however, their evaluation has not been investigated. This study developed an evaluation framework, which was tested in informal settlements in Kampala for sustainable business models of fecal sludge emptying and transport. Through key informant interviews and stakeholder consultations, service delivery challenges from informal settlements in Kampala were identified and included in the framework, which were: high cost of emptying services, spillages, access to facilities, high operational costs and social stigma. The evaluation framework adopted six service criteria: Financial, Institutional, Environmental, Technological, Social and Scalability; these were further defined by fifteen service sub-criteria. The criteria were tested separately on eight business models—for mechanized (cesspool) and semi-mechanized (gulper) technologies. The key output of the evaluation framework (business model scorecard) revealed that two models (scheduled desludging and call center) for cesspool technology and three models (mobile transfer stations, scheduled desludging and call center) for gulper technology have high potential for service improvement in informal settlements. Scheduled desludging and mobile transfer stations can effectively optimize emptying services and subsequently reduce emptying charges, whereas the call center is critical for bridging service delivery. Full article

Acrylic manufacturing wastewater is characterized by high toxicity, poor biodegradability, high chemical oxygen demand (COD) and ammonia nitrogen. Herein, we exploited traditional Fenton technology to treat acrylic fiber manufacturing wastewater. The impacts of key operating variables including the initial concentration of H₂O₂ (C_H2O2), the initial concentration of Fe²⁺ (D_Fe2+), and solution pH (pH) on the COD removal rate (R_COD) were explored and the treatment process was optimized by Response Surface Methodology (RSM). The results indicated that the optimum parameters are determined as pH 3.0, 7.44 mmol/L of Fe²⁺ and 60.90 mmol/L of H₂O₂ during Fenton process. For the actual acrylic manufacturing wastewater treatment shows that the removal rates for COD, TOC, NH₄⁺-N and TN are 61.45%~66.51%, 67.82%~70.99%, 55.67%~60.97% and 56.45%~61.03%, respectively. It can meet the textile dyeing and finishing industry water pollutant discharge standard (GB4287-2012). During the Fenton reaction, the effective degradation and removal of organic matter is mainly achieved by HO• oxidation, supplemented by flocculation and sedimentation of Fe³⁺ complexes. This study will provide useful implications in the process parameters for the practical application of Fenton method in acrylic acid production wastewater. Full article

Contamination assessment and source analysis of urban waterways are important for the environmental management of water resources. This study applied an improved water quality index (WQI), which was called WQI-DET (water quality index deterioration) to analyze the Fenjiang River’s (Foshan City, South China) water quality monitoring data from 2016 to 2021. Between 2016 and 2021, the Fenjiang River had the highest WQI-DET value in 2016. Since then, the water quality has shown a decreasing trend year by year. Then, through Spearman analysis, it was identified that the chemical oxygen demand (COD) and ammonia nitrogen (NH₃-N) are the main factors of water quality deterioration. Moreover a Bayesian model was used to analyze and evaluate the main factors. On this basis, relationships between COD, NH₃-N, the natural environment, and human activities were analyzed by principal component analysis. The results showed that NH₃-N has been the main factor affecting the water quality in recent years and there were no significant changes in COD and NH₃-N during the study period. However, COD and NH₃-N showed significant differences in spatial distribution. Meanwhile, human activities contributed 52.3% to the variability in the water quality of the Fenjiang River, and natural factors only 26.8%; factors not considered in this study contributed the remaining 20.9%. Human activities had a more significant impact on the water quality of the Fenjiang River than natural factors. Full article

Oil leakage occurs at fuel service stations due to improper storage, which pollutes soil and, subsequently, can reach the groundwater. Many compounds of petroleum-derived fuels pose hazards to aquatic systems, and so must be treated to guarantee clean and safe consumption, which is a right proposed by the United Nations in their Sustainable Development Goal 6 (SDG 6: Clean Water and Sanitation). In this study, contaminated groundwater with emerging pollutants by petroleum-derived fuel was electrochemically treated in constantly mixed 0.5 L samples using three different anodes: Ni/BDD, Ti/Pt, Ti/RuO₂. Parameters were investigated according to chemical oxygen demand (COD), energy consumption analysis, by applying different electrodes, current densities (j), time, and the use of Na₂SO₄ as an electrolyte. Despite a similar COD decrease, better degradation was achieved after 240 min of electrochemical treatment at Ti/RuO₂ system (almost 70%) by applying 30 mA cm⁻², even without electrolyte. Furthermore, energy consumption was lower with the RuO₂ anode, and greater when 0.5 M of Na₂SO₄ was added; while the order, when compared with the other electrocatalytic materials, was Ti/RuO₂ > Ti/Pt > Ni/BDD. Thereafter, aiming to verify the viability of treatment at a large scale, a pilot flow plant with a capacity of 5 L was used, with a double-sided Ti/RuO₂ as the anode, and two stainless steel cathodes. The optimal conditions for the effective treatment of the polluted water were a j of 30 mA cm⁻², and 0.5 M of Na₂SO₄, resulting in 68% degradation after 300 min, with almost complete removal of BTEX compounds (benzene, toluene, ethyl-benzene, and xylene, which are found in emerging pollutants) from the water and other toxic compounds. These significant results proved that the technology used here could be an effective SDG 6 electrochemical-based solution for the treatment of groundwater, seeking to improve the quality of water, removing contaminants, and focusing on Brazilian environmental legislations and, consequently, converting pollutants into effluent that can be returned to the water cycle. Full article

Many studies have applied the Long Short-Term Memory (LSTM), one of the Recurrent Neural Networks (RNNs), to rainfall-runoff modeling. These data-driven modeling approaches learn the patterns observed from input and output data. It is widely known that the LSTM networks are sensitive to the length and quality of observations used for learning. However, the discussion on a better composition of input data for rainfall-runoff modeling has not yet been sufficiently conducted. This study focuses on whether the composition of input data could help improve the performance of LSTM networks. Therefore, we first examined changes in streamflow prediction performance by various compositions of meteorological variables which are used for LSTM learning. Second, we evaluated whether learning by integrating data from all available basins can improve the streamflow prediction performance of a specific basin. As a result, using all available meteorological data strengthened the model performance. The LSTM generalized by the multi-basin integrated learning showed similar performance to the LSTMs separately learned for each basin but had more minor errors in predicting low flow. Furthermore, we confirmed that it is necessary to group by selecting basins with similar characteristics to increase the usefulness of the integrally learned LSTM. Full article

We first report the presence of a species of the genus Batophora in the Iberian Peninsula, in the Mar Menor lagoon (Murcia, SE Spain). We detected this macroalga in November 2021. However, according to some observations, it could have been present in the lagoon at least since 2016, being described as a “rare” form of Dasycladus vermicularis. A further survey made during May 2022 confirmed the presence of this species in much of the perimeter of the Mar Menor. Morphologic analyses are not conclusive regarding the species description, but most traits point to Batophora occidentalis or Batophora occidentalis var. largoensis. A consensus sequence from the rbcL barcode gene was compared by the Blastn tool showing its closeness to other Batophora specimens, yet the specific level was unresolved. The recent confirmation of a Batophora species in a littoral lagoon from Formentera (Balearic Islands) with similar morphologic characteristics could indicate that both putative introductions are connected. Further morphologic and genetic analyses are required in order to know the origin and expansion of this genus along the Mediterranean coasts. Full article

A shortage of water resources is a global issue of common concern. The contribution of the article mainly includes the following two parts. First is the study of water resources’ green utilization efficiency (WRGUE) in 30 provincial administrative units of China from 2009 to 2019 by adopting the epsilon-based measure (EBM) model with undesirable outputs, which can yield a more accurate and reasonable assessment result. In addition, the spatial Durbin model was applied to analyze the driving factors of the WRGUE, which considers the spatial effects. The results are as follows: (1) The discrepancy of the WRGUE in different regions of China is conspicuous, with the highest in East China, followed by the central and the western region, while the Northeast is the lowest. A general decrease trend from China’s southeast coastal area to the northwest inland is presented. (2) Global spatial autocorrelation analysis shows a significant positive spatial autocorrelation in the WRGUE of the 30 sample provinces. However, the local spatial autocorrelation analysis shows that the WRGUE in China presents stronger spatial homogeneity than heterogeneity. (3) The levels of technology advancement, economic development, and the Opening-up policy implementation serve as positive factors influencing the WRGUE in China. On the contrary, the urbanization level has a significant negative impact on the WRGUE. The results of this paper may have great value for sustainable water resource utilization. Full article

At the international level, the term “water security” (WS) has gained increasing attention in recent decades. At the operational level, WS is assessed using tools that define the concept using a variety of dimensions and sub-dimensions, with qualitative and quantitative indicators and parameters. The breadth of tools and concepts is an obstacle to the operationalisation of the concept of water security (WS). Clearly, we need a range of diverse data to evaluate water security (WS). However, there are several barriers to designing an optimal Data Gathering Strategy (DGS). Such a strategy must strike a balance between a wide range of competing and overlapping data requirements and characteristics including: resources, information, and impact. The proposed framework aims at filling the existing gaps, not by providing a strict procedure, but instead acting as a “compass”: five interfaces between data and context are identified to orient practitioners towards an optimal DGS. The conceptual aim of the framework can be summarised as shifting the focus of the DGS from a “data-to-information approach” to a “data-to-action approach,” therefore stressing the importance of reaching key stakeholders with information. The specific aims of this paper are to: identify the key issues that should be addressed in designing a Data Gathering Strategy for Water Security (DGSxWS); communicate the key issues with a clear conceptual framework; and suggest approaches and activities that could help water practitioners in dealing with the issues identified. Full article