Editor’s Choice Articles

It is fundamentally challenging to quantify the uncertainty of data-driven flood forecasting. This study introduces a general framework for probabilistic flood forecasting conditional on point forecasts. We adopt an unscented Kalman filter (UKF) post-processing technique to model the point forecasts made by a recurrent neural network and their corresponding observations. The methodology is tested by using a long-term 6-h timescale inflow series of the Three Gorges Reservoir in China. The main merits of the proposed approach lie in: first, overcoming the under-prediction phenomena in data-driven flood forecasting; second, alleviating the uncertainty encountered in data-driven flood forecasting. Two commonly used artificial neural networks, a recurrent and a static neural network, were used to make the point forecasts. Then the UKF approach driven by the point forecasts demonstrated its competency in increasing the reliability of probabilistic flood forecasts significantly, where predictive distributions encountered in multi-step-ahead flood forecasts were effectively reduced to small ranges. The results demonstrated that the UKF plus recurrent neural network approach could suitably extract the complex non-linear dependence structure between the model’s outputs and observed inflows and overcome the systematic error so that model reliability as well as forecast accuracy for future horizons could be significantly improved. Full article

Water literacy has become a fundamental aspect in today’s society, as its conservation, preservation and management is key to ensuring human survival. The purpose of this paper was to analyze the effectiveness of flipped learning methodology on a traditional training practice in water literacy at the first level of secondary education. The flipped learning method consisted in providing the contents to the students before the class sessions, encouraging an active learning. A descriptive study was adopted with two experimental groups, two control groups and only post-test. An ad hoc questionnaire was used as an instrument to measure the parameters: Socio-educational, Motivation, Interactions, Autonomy, Collaboration; Deepening of contents; Problem solving, Class time and Ratings. The final sample was composed of 120 students, divided into four groups of 30 students each. The application of the treatment in the experimental groups lasted 10 sessions of 55 min. The results indicate that the use of time in class, the autonomy and the deepening of the contents were the aspects that improved most with the flipped learning approach. However, no significant differences in ratings were found. Finally, the main findings and their implications for water literacy are discussed. Full article

Green infrastructure (GI) systems are often overdesigned. This may be a byproduct of static sizing (e.g., accounting for a design storm’s runoff volume but not exfiltration rates) or may be deliberate (e.g., buffering against performance loss through time). In tree trenches and other GI systems that require stormwater to accumulate in an infiltration bed before it contacts the planting medium, overdesign could reduce plant water availability significantly. This study investigated the hydrological dynamics and water relations of an overdesigned tree trench system and identified factors contributing to, compounding, and mitigating the risk of plant stress. Water in the infiltration bed reached soil pits only once in three years, with that event occurring during a hydrant release. Moreover, minimal water was retained in soil pits during the event due to the hydraulic properties of the soil media. Through a growing season, one of the two tree types frequently experienced water stress, while the other did so only rarely. These contrasting responses can likely be attributed to roots being largely confined to the soil pits vs. reaching a deeper water source, respectively. Results of this study demonstrate that, in systems where soil pits are embedded in infiltration beds, overdesign can raise the storm size required for water to reach the soil media, reducing plant water availability between storms, and ultimately inducing physiological stress. Full article

This work assessed the groundwater hydrogeochemistry and the drinking water quality of 10 wells supplying the urban area of Zamora, Michoacán, Mexico. Two sampling campaigns were conducted in May 2018 (dry season) and November 2018 (wet season) to describe the chemistry of the water and its interaction with the rock. Physical and chemical constituents (temperature, pH, electrical conductivity, color, turbidity, solids, total hardness, total alkalinity, chemical and biochemical oxygen demands), major components (Ca²⁺, Mg²⁺, Na⁺, K⁺, SO₄²⁻, PO₄³⁻, HCO₃⁻, CO₃²⁻, Cl⁻, N-NO₃⁻, and N-NH₃), as well as trace elements (As, Fe, Mn, Ba, Al, Sb, Co, V, Cu, Cd, Cr, Ni, Zn, Tl, Pb) were analyzed. Results showed groundwater with a slight tendency to alkalinity. The hydrogeochemical facies observed are Ca²⁺-HCO₃⁻ in all sites. Hydrochemical diagrams indicate immature, cold, non-saline, and uncontaminated water with short residence time. Water–rock interaction predominates. The water in the study area is appropriate for drinking use according to Mexican and international regulations with an excellent quality in 7 wells and good in the other 3. Full article

This paper proposes a methodology for the analysis of social vulnerability to floods based on the integration and weighting of a range of exposure and resistance (coping capacity) indicators. It focuses on the selection and characteristics of each proposed indicator and the integration procedure based on the analytic hierarchy process (AHP) on a large scale. The majority of data used for the calculation of the indicators comes from open public data sources, which allows the replicability of the method in any area where the same data are available. To demonstrate the feasibility of the method, a study case is presented. The flood social vulnerability assessment focuses on the municipality of Ponferrada (Spain), a medium-sized town that has high exposure to floods due to potential breakage of the dam located upstream. A detailed mapping of the social vulnerability index is generated at the urban parcel scale, which shows an affected population of 34,941 inhabitants. The capability of working with such detailed units of analysis for an entire medium-sized town provides a valuable tool to support flood risk planning and management. Full article

It is difficult for a one-dimensional river network hydrodynamic model to manage bifurcations. Traditional methods use simplified junction methods to avoid solving physical equations at bifurcations, which can cause physical distortions and errors. In this article, we propose an algorithm that allows a Eulerian–Lagrangian method (ELM) to track through bifurcations then solve advective terms, in combination with velocity–pressure couplings, to solve physical equations at bifurcations. The new method discards the simplifications and assumptions used by traditional models and is more complete in theory. We tested the new method with two ideal examples, and the results showed that the new method is time-step independent and grid independent. A simple bifurcation was used to compare this method with MIKE11. Full article

Excessive levels of Fe, Mn and As are the main factors affecting groundwater quality in Songliao plain, northeast China. However, there are few studies on the source and mobilization mechanisms of Fe, Mn and As in the groundwater of Northeastern China. This study takes Shuangliao city in the middle of Songliao plain as an example, where the source and mobilization mechanisms of iron, manganese and arsenic in groundwater in the study area were analyzed by statistical methods and spatial analysis. The results show that the source of Fe and Mn in the groundwater of the platform is the iron and manganese nodules in the clay layer, while, in the river valley plain, it originates from the soil and the whole aquifer. The TDS, fluctuation in groundwater levels and the residence time are the important factors affecting the content of Fe and Mn in groundwater. The dissolution of iron and manganese minerals causes arsenic adsorbed on them to be released into groundwater. This study provides a basis for the rational utilization of groundwater and protection of people’s health in areas with high iron, manganese and arsenic contents. Full article

Certain relevant variables for dam safety and downstream safety assessments are analyzed using a stochastic approach. In particular, a method to estimate quantiles of maximum outflow in a dam spillway and maximum water level reached in the reservoir during a flood event is presented. The hydrological system analyzed herein is a small mountain catchment in north Spain, whose main river is a tributary of Ebro river. The ancient Foradada dam is located in this catchment. This dam has no gates, so that flood routing operation results from simple consideration of fixed crest spillway hydraulics. In such case, both mentioned variables (maximum outflow and maximum reservoir water level) are basically derived variables that depend on flood hydrograph characteristics and the reservoir’s initial water level. A Monte Carlo approach is performed to generate very large samples of synthetic hydrographs and previous reservoir levels. The use of extreme value copulas allows the ensembles to preserve statistical properties of historical samples and the observed empirical correlations. Apart from the classical approach based on annual periods, the modelling strategy is also applied differentiating two subperiods or seasons (i.e., summer and winter). This allows to quantify the return period distortion introduced when seasonality is ignored in the statistical analysis of the two relevant variables selected for hydrological risk assessment. Results indicate significant deviations for return periods over 125 years. For the analyzed case study, ignoring seasonal statistics and trends, yields to maximum outflows underestimation of 18% for T = 500 years and 29% for T = 1000 years were obtained. Full article

There is increasing interest in using Unmanned Aircraft Systems (UAS) in flood risk management activities including in response to flood events. However, there is little evidence that they are used in a structured and strategic manner to best effect. An effective response to flooding is essential if lives are to be saved and suffering alleviated. This study evaluates how UAS can be used in the preparation for and response to flood emergencies and develops guidelines for their deployment before, during and after a flood event. A comprehensive literature review and interviews, with people with practical experience of flood risk management, compared the current organizational and operational structures for flood emergency response in both England and India, and developed a deployment analysis matrix of existing UAS applications. An online survey was carried out in England to assess how the technology could be further developed to meet flood emergency response needs. The deployment analysis matrix has the potential to be translated into an Indian context and other countries. Those organizations responsible for overseeing flood risk management activities including the response to flooding events will have to keep abreast of the rapid technological advances in UAS if they are to be used to best effect. Full article

The ecological water quality in rivers and streams is influenced both by the morphological factors (within the watercourse channel and by the dynamic factors associated with flow), as well as biological factors (connected with the flora and fauna characteristic of its specific area). This paper presents an analysis of the effect of river channel shading by trees and shrubs on hydromorphological changes in a selected reach of the Wełna River, Poland. The analysis was conducted on two adjacent cross-sections (one in a reach lined with trees, the other in an open area with no tree or shrub vegetation). Data were collected during field surveys in the years 2014 and 2019. According to the Water Framework Directive, the Wełna River represents a watercourse with small and average-sized watershed areas, with sand being the dominant substrate of the river bottom. Flow volume, distributions of velocity in the sections, as well as substrate grain-size characteristics and river bottom morphology, were determined based on field measurements. In the study, the leaf area index (LAI) of vegetation was measured in the reach lined with trees, while the number and species composition of macrophytes were determined in the investigated river reaches. Moreover, a digital surface model (DSM) and Geoinformation Information System GIS tools were used to illustrate variability in shading within the tree-lined reach. The DSM model was based on Light Detection and Ranging (LIDAR) data. The results of this study enable us to establish the relationship between river shading by vegetation covering the bank zone, and changes in hydromorphological parameters of the river channel. Full article

Oceanic-atmospheric phenomena of different time scales concurrently might affect the streamflow in several basins around the world. The Atrato River Basin (ARB) and Patía River Basin (PRB) of the Colombian Pacific region are examples of such basins. Nevertheless, the relations between the streamflows in the ARB and PRB and the oceanic-atmospheric factors have not been examined considering different temporal scales. Hence, this article studies the relations of the climate indices and the variability of the streamflows in the ARB and PRB at interannual and decadal timescales. To this, the streamflow variability modes were obtained from the principal component analysis (PCA); furthermore, their linear dependence with indices of the El Niño/Southern Oscillation (ENSO), precipitation (PRP), the Choco low-level jet (CJ), and other indices were quantified through (a) Pearson and Kendall’s tau correlations, and (b) wavelet transform. The PCA presented a single significant mode for each basin, with an explained variance of around 80%. The correlation analyses between the PC1s of the ARB and PRB, and the climate indices showed significant positive (negative) high correlations with PRP, CJ, and Southern Oscillation Index (SOI) (ENSO indices). The wavelet coherence analysis showed significant coherencies between ENSO and ARB: at interannual (2–7 years) and decadal scale (8–14), preferably with the sea surface temperature (SST) in the east and west Tropical Pacific Ocean (TPO). For PRB with the SST in the central and western regions of the TPO in the interannual (4–8 years) and decadal (8–14 years) scales, the decreases (increases) in streamflow precede the El Niño (La Niña) events. These results indicate multiscale relations between the basins’ streamflow and climate phenomena not documented in previous works, relevant to forecast the extreme flow events in the Colombian Pacific rivers and for planning and implementing strategies for the sustainable use of water resources in the basins studied. Full article

The Baltic Sea represents one of the largest brackish ecosystems where various environmental factors control dynamic seasonal shifts in the structure, diversity, and function of the planktonic microbial communities. In this study, despite seasonal fluctuations, several bacterial populations (<2% of the total OTUs) that are highly dominant (25% of relative abundance) and highly frequently occurring (>85% of occurrence) over four seasons were identified. Mathematical models using occurrence frequency and relative abundance data were able to describe community assembly persisting over time. Further, this work uncovered one of the core bacterial populations phylogenetically affiliated to SAR11 subclade IIIa. The analysis of the hypervariable region of 16S rRNA gene and single copy housekeeping genes recovered from metagenomic datasets suggested that the population was unexpectedly evolutionarily closely related to those inhabiting a mesosaline lacustrine ecosystem rather than other marine/coastal members. Our metagenomic results further revealed that the newly-identified population was the major driver facilitating the seasonal shifts in the overall community structure over the brackish waters of the Baltic Sea. The core community uncovered in this study supports the presence of a brackish water microbiome distinguishable from other marine and freshwater counterparts and will be a useful sentinel for monitoring local/global environmental changes posed on brackish surface waters. Full article

Six bias correction (BC) methods; delta-method (DT), linear scaling (LS), power transformation of precipitation (PTR), empirical quantile mapping (EQM), gamma quantile mapping (GQM) and gamma-pareto quantile mapping (GPQM) were applied to adjust the biases of historical monthly precipitation outputs from five General Circulation Models (GCMs) dynamically downscaled by two Regional Climate Models (RCMs) for a total of seven different GCM-RCM pairs over Costa Rica. High-resolution gridded precipitation observations were used for the control period 1951–1980 and validated over the period 1981–1995. Results show that considerable biases exist between uncorrected GCM-RCM outputs and observations, which largely depend on GCM-RCM pair, seasonality, climatic region and spatial resolution. After the application of bias correction, substantial biases reductions and comparable performances among most BC methods were observed for most GCM-RCM pairs; with EQM and DT marginally outperforming the remaining methods. Consequently, EQM and DT were selectively applied to correct the biases of precipitation projections from each individual GCM-RCM pair for a near-future (2011–2040), mid-future (2041–2070) and far-future (2071–2100) period under Representative Concentration Pathways (RCPs) 2.6, 4.5 and 8.5 using the control period 1961–1990. Results from the bias-corrected future ensemble-mean anticipate a marked decreasing trend in precipitation from near to far-future periods during the dry season (December, January, February (DJF) and March, April, May (MAM)) for RCP4.5 and 8.5; with pronounced drier conditions for those climatic regions draining towards the Pacific Ocean. In contrast, mostly wetter conditions are expected during the dry season under RCP2.6, particularly for the Caribbean region. In most of the country, the greatest decrease in precipitation is projected at the beginning of the rainy season (June, July, August (JJA)) for the far-future period under RCP8.5, except for the Caribbean region where mostly wetter conditions are anticipated. Regardless of future period, slight increases in precipitation with higher radiative forcing are expected for SON excluding the Caribbean region, where precipitation is likely to increase with increasing radiative forcing and future period. This study demonstrates that bias correction should be considered before direct application of GCM-RCM precipitation projections over complex territories such as Costa Rica. Full article

Due to excessive resource consumption and pressing environmental issues of the sewage treatment industry, there is extensive attention in China. Given the unique craft production process in the sewage treatment system, a series of integral emergy indicators have been used to evaluate the environmental sustainability based on infrastructure construction and operation stage emergy analysis. Taking a new typical sewage treatment plant as an example, this paper performed a case study. The results illustrate that (1) the infrastructure construction process emergy (approximate 92.6%) is more critical than sewage treatment process emergy; (2) nonrenewable resource is the primary factor for the emergy analysis, followed by energy (23.5%) and purchased supply (7%); (3) cement, steel, and gravel have dominant impacts on the nonrenewable resource emergy; (4) the emergy sustainability index is 0.001101, which displays weak environmental sustainability; (5) the unit emergy value (UEV) of the new sewage treatment plant is 3.40 × 10¹² sej/m³; (6) sensitivity analysis results of the hypothesis demonstrate that nonrenewable resources have significant fluctuations (6.903%) while, for the indicators, emergy sustainability index (ESI) (4.8072%) has the most significant impact; and (7) wastewater is a major contributor. In light of comprehensive discussions, two positive measures are proposed in order to ameliorate the environmental sustainability. Full article

The paper examines the nature and performance of participatory water institutions in eastern India using structural equation modelling. There is a crisis in the management of water in India, and this is often not about having too little water but about managing it poorly. It is now being widely recognized that engineering structures and solutions are not enough, and having effective water institutions is critical. These are urgently needed in eastern India for helping lift the region out of low incomes and poverty. However, creating good institutions is complex, and in this context, the fundamentals of new institutional economics, and management governance theory have suggested the importance of a number of key factors including five institutional features and eight rationalities. Based on this, a study was conducted in eastern India, sampling from the states of Assam and Bihar, covering 510 farm households across 51 water institutions. In order to understand and map the relationship and pathways across these key factors, a structural equation model is hypothesized. In the model, the five institutional features are considered determinants of the eight rationalities, and the rationalities are considered determinants of four performance goals. The performance on the goals determines the overall performance/success of the institution. Besides this, the institutional features and rationalities can also directly influence performance on the goals and the overall performance. The model is tested with data from the survey and different pathways that are robust are identified. The results can provide useful insights into the interlinkages and pathways of institutional behavior and can help policy and institution design for delivering more robust performance. The results show that one of the most important factors determining overall performance/success is technical rationality, and this deserves great attention. It includes technical expertise, sound location and quality of structures and equipment, and good maintenance. However, success is also strongly linked to performance on production/income goals, equity, and environment goals. These are, in turn, strongly related to achievement of economic, social, technical, and organizational rationalities, which call for attention to economic aspects such as crop choice and marketing, besides social aspects such as inclusion of women and poorer social groups, and organizational aspects such as member involvement and regular meetings. Further, the institutional features of clear objectives, good interactions, adaptive, correct scale, and compliance are important for achievement of almost all rationalities through various pathways, and should be strongly focused on in all the institutions. Full article

Drought is a severe threat, especially in the arid regions of Pakistan, such as the Balochistan Province. The aim of this study is to analyze drought trends in Balochistan using Standard Precipitation Index (SPI) at the 3-month accumulation timescale. The monthly rainfall data of 10 stations were collected from the Pakistan Meteorological Department (PMD) for 37 years (1980–2017). Drought trends were analyzed at each station using the Mann-Kendall test. The SPI identified extreme drought events in 1996, 2001, 2002, 2004, 2009, and 2014. Barkhan was the station that most frequently experienced extreme to severe drought events, as defined using SPI. A statistically significant decreasing precipitation trend was found in four stations (Dalbandin, Jiwani, Quetta, and Zhob). The analysis of drought characteristics showed Barkhan faced the most prolonged drought, of 22 months from 1999 to 2001. The findings from the present study can give guidance on how strategies of water management should be adjusted based on the changing patterns of droughts in the Balochistan Province. Full article

This research work is intended as a contribution to the development of a multicriteria methodology, combining several factors to control the availability of groundwater resources, in order to optimize the choice of location of future drilling and increase the chances to take water from productive structures which will satisfy the ever-increasing water demand of local population (Arghen basin in the Western Anti-Atlas chain of Morocco). The geographic information system is used to develop thematic maps describing the geometry and the hydrodynamic functioning of the aquifer. In this study, 11 factors including geology, topography, and hydrology, influencing the distribution of water resources were used. Based on the Analytical Hierarchy Process (AHP) model, GIS, and remote sensing, the study mapped and classified areas according to their hydrogeological potential. The favorable potential sectors cover 17% of the total area of the basin. The medium potential sectors account for 64%, while the unfavorable areas cover 18% of the basin area. The groundwater potential map of the study area has been validated by comparing with data from 159 boreholes scattered throughout the basin. Full article

Storm surges are one of the main drivers for extreme flooding at the coastal areas. Such events can be characterized with the maximum level in an extreme storm surge event (surge peak), as well as the duration of the event. Surge projections come from a barotropic model for the 1950–2100 period, under a severe climate change scenario (RCP 8.5) at the northeastern Spanish coast. The relationship of extreme storm surges to three large-scale climate patterns was assessed: North Atlantic Oscillation ( $NAO$ ), East Atlantic Pattern ( $EAWR$ ), and Scandinavian Pattern ( $SC$ ). The statistical model was built using two different strategies. In Strategy #1, the joint probability density was characterized by a moving-average series of stationary Archimedean copula, whereas in Strategy #2, the joint probability density was characterized by a non-stationary probit copula. The parameters of the marginal distribution and the copula were defined with generalized additive models. The analysis showed that the mean values of surge peak and event duration were constant and were independent of the proposed climate patterns. However, the values of $NAO$ and $SC$ influenced the threshold and the storminess of extreme events. According to Strategy #1, the variance of the surge peak and event duration increased with a fast shift of negative $SC$ and a positive $NAO$ , respectively. Alternatively, Strategy #2 showed that the variance of the surge peak increased with a positive $EAWR$ . Both strategies coincided in that the joint dependence of the maximum surge level and the duration of extreme surges ranged from low to medium degree. Its mean value was stationary, and its variability was linked to the geographical location. Finally, Strategy #2 helped determine that this dependence increased with negative $NAO$ . Full article

As a method for eco-efficiency analysis, environmental cost efficiency (ECE) indicators have been proposed for the end-of-pipe (EOP) systems that referred to the techniques achieving environmental benefit under economic cost. The wastewater treatment plant (WWTP) belongs to the EOP systems; however, few studies used the ECE indicators for the sustainability evaluation. Here, this study first proposed the following processes that had been excluded in the current ECE framework and thus limited the potential application in WWTP: (1) the direct impact of wastewater on receiving water, (2) the migration and transformation of water pollutants affected by the self-purification mechanisms of receiving water. To address the aforementioned processes, this study extended the framework of ECE indicators by means of incorporating the potential growth of microorganisms as the characterization state and integrating the water quality models with the characterization models. To investigate the applicability, a full-scale WWTP was selected as the study case and the eco-efficiency of the increasing levels of sewage treatment was evaluated. The case outcome showed that, with the extended ECE indicators, the analysis of eco-efficiency could be directly related to the specific locations and could determine the specific distance ranges within which the scenarios changing were considered efficient. Moreover, the eco-efficiency could be investigated under more concrete and flexible situations because the extended framework of ECE indicators was able to include more information, such as different types of receiving water or different environmental conditions of certain water body. Full article

Urban rivers affected by anthropogenic activities can act as reservoirs of antibiotic resistance genes (ARGs). This study aimed to describe the occurrence of selected ARGs (bla_TEM, ermF, mecA, and tetA) and a class 1 integron (intI1) in an urban river in Nepal. A total of 18 water samples were collected periodically from upstream, midstream, and downstream sites along the Bagmati River over a 1-year period. All ARGs except mecA and intI1 were consistently detected by a quantitative polymerase chain reaction in the midstream and downstream sites, with concentrations ranging from 3.1 to 7.8 log copies/mL. ARG abundance was significantly lower at the upstream site (p < 0.05), reflecting the impact of anthropogenic activities on increasing concentrations of ARGs at midstream and downstream sites. Our findings demonstrate the presence of clinically relevant ARGs in the urban river water of Nepal, suggesting a need for mitigating strategies to prevent the spread of antibiotic resistance in the environment. Full article

The adsorption properties of coexistent Cr(VI) and Cu(II) in mixed solution on magnetic magnetite (Fe₃O₄) nanoparticle were studied in batch experiments. The influences of various factors, such as pH, adsorbent dose, temperature, initial concentration of metal ions, and coexisting ions in water were investigated. At the same time, the adsorption kinetics and adsorption isotherms were studied. The mechanism of adsorption for Cr(VI) and Cu(II) was investigated through the study of surface properties of Fe₃O₄, the presence of ions, and the influence of pH and zeta potential. The results indicate that pH has an influence on adsorption for Cr(VI) and Cu(II), and the optimal pH value for Cr(VI) and Cu(II) adsorption is 4.0. The adsorption efficiency increased with the increase of the adsorbent dose. Temperature under experimental design had no obvious effect. With 2.0 g/dm³ Fe₃O₄, the maximum adsorption capacity for Cr(VI) and Cu(II) reached 8.67 mg/g and 18.61 mg/g in mixed solution of 80 mg/dm³ Cr(VI) and Cu(II), respectively. Phosphorus had some influence on the adsorption for Cr(VI), and other coexisting anions and cations had no influence on the adsorption for Cr(VI) and Cu(II). The adsorption data for Cr(VI) and Cu(II) were nicely fit to the Langmuir adsorption equation and the pseudo-second-order model. As a multifunctional material, nano-Fe₃O₄ exhibited good adsorption performance for coexistent Cr(VI) and Cu(II) and could easily be separated and recovered under magnetic field. Full article

Flow forecasting is an essential topic for flood prevention and mitigation. This study utilizes a data-driven approach, the Long Short-Term Memory neural network (LSTM), to simulate rainfall–runoff relationships for catchments with different climate conditions. The LSTM method presented was tested in three catchments with distinct climate zones in China. The recurrent neural network (RNN) was adopted for comparison to verify the superiority of the LSTM model in terms of time series prediction problems. The results of LSTM were also compared with a widely used process-based model, the Xinanjiang model (XAJ), as a benchmark to test the applicability of this novel method. The results suggest that LSTM could provide comparable quality predictions as the XAJ model and can be considered an efficient hydrology modeling approach. A real-time forecasting approach coupled with the k-nearest neighbor (KNN) algorithm as an updating method was proposed in this study to generalize the plausibility of the LSTM method for flood forecasting in a decision support system. We compared the simulation results of the LSTM and the LSTM-KNN model, which demonstrated the effectiveness of the LSTM-KNN model in the study areas and underscored the potential of the proposed model for real-time flood forecasting. Full article

This research has focused on the source identification, concentration, and ecological risk assessment of eight heavy metals in the largest karst wetland (Huixian) of south China. Numerous samples from superficial soil and sediment within ten representative landuse types were collected and examined, and the results were analyzed using multiple methods. Single pollution index (Pi) results were underpinned by the Geoaccumulation index (I_geo) method, in which Cd was observed as the priority pollutant with the highest contamination degree in this area. As for the most polluted landuse type, via applying Nemerow’s synthetical contamination index (P_N) and Potential ecological risk index (RI), the river and rape field posed the highest ecological risks, while moderate for the rest. To quantify the drivers of the contaminants, a principal component analysis (PCA) was carried out and weathering of the watershed’s parent carbonate rocks was found to be the main possible origin, followed by anthropogenic sources induced by agricultural fertilizer. Considering the impacts of these potentially toxic elements on public health, the results of this study are essential to take preventive actions for environmental protection and sustainable development in the region. Full article

This work compares three forcing schemes for a recently introduced cascaded lattice Boltzmann shallow water model: a basic scheme, a second-order scheme, and a centred scheme. Although the force is applied in the streaming step of the lattice Boltzmann model, the acceleration is also considered in the transformation to central moments. The model performance is tested for one and two dimensional benchmarks. Full article

Water shortage, water pollution, shrinking water area and water mobility are the main contents of the water resources crisis, which are widespread in the social and economic development of Jilin Province. In this paper, a three-stage hybrid model integrating evaluation, prediction and regulation is constructed by combining the load-balance method and the system dynamics method. Using this model, the current states of water resources carrying capacity (WRCC) in 2017 and the trend of water demand/available from 2018 to 2030 were obtained. Using the orthogonal test method, the optimal combination program of agricultural and industrial water efficiency regulation and water resources allocation was selected. The results show that the pressure of the human–water resources system in Changchun, Liaoyuan and Baicheng is greater than the support, and the other six cities are not overloaded. The water demand in Jilin Province and its nine cities will increase from 2018 to 2030, if the current socio-economic development pattern is maintained. Therefore, we change the water quantity carrying capacity index by controlling agriculture, industrial water efficiency and trans-regional water transfer. Compared with 2015, among the optimal program obtained, the change range of the water use per 10,000 RMB of agricultural output is (−5%, 25%), and the water use per 10,000 RMB of industrial added value is (−45%, −35%), and the maximum water transfer is 1.5 billion m³ per year in 2030. This study analyzes the development pattern of WRCC in the process of water conservancy modernization in Jilin Province and provides reference for other provinces to make the similar plan. Full article

This paper aims at evaluating the wave overtopping discharge over the pavement of “Piazza S. Marco” (Venice) in order to select the best option to mitigate the risk of flooding of the Piazza and to protect the monuments and historic buildings, e.g., the “Basilica S. Marco”. In fact, the MO.S.E. (MOdulo Sperimentale Elettromeccanico) system is designed to keep the water level below a certain value, for the safety of the lagoon, but it does not guarantee the defence of the Piazza, where flooding is still possible, being its pavement locally much lower than the maximum expected water level. To completely defend the Piazza, specific additional works are planned to prevent the back-flow through the natural drainage system (now the primary pathway) or by filtration or by overtopping. This paper investigates on the overtopping mechanism, under conditions compatible with a fully operational MO.S.E. system, through 2-D experiments. The pavement of the Piazza is gently sloping towards the masonry quay which, in some parts is formed by 5 descending steps, and in some other parts, is just a vertical wall. Close to the “Marciana” Library, a critical part is present, with a slightly lower crest freeboard. In total, three cross-sections were examined in the 36 m long wave flume of the Padova University. The test programme includes 10 irregular wave attacks and three different water levels. The test results differ considerably from the results of the available formulas, since the investigated cross-sections by far exceed their range of applicability. The presence of the steps affects only the reflection coefficient rather than the overtopping discharges. In general, if the waves incident to the Piazza are higher than 40 cm, which is a possible scenario, some other adaptation works must be considered, such as the pavement rise, temporary barriers or the reduction of the waves impacting the quay through, for instance, floating breakwaters. Full article

Globally, some 2.5 billion people depend solely on groundwater to satisfy their daily drinking water needs. The reliance on this resource and its centrality to realize the human right to ‘safe’ drinking water has increased manifold, but this is yet to be fully acknowledged globally or by governments and political leaders at the national level. This paper analyses the interface of international human rights law, as corresponding to the obligations and responsibilities of different actors, regarding groundwater resources planning, management and protection. Drawing on the literature, we discuss the State’s duties to respect, protect and fulfil this right especially in relation to the freedom of end-users to self-supply from groundwater sources; the training and regulation of non-State service providers including drillers and private vendors; and health and safety concerns. Interpreting the State’s duty to ‘fulfil’ through direct water service provision ‘as a last resort’, this paper suggests that self-provision is the original norm for enjoying the right to water. This has significant implications for the State’s role in raising awareness concerning point source protection and aquifer recharge for water resources management and in decisions concerning water allocation. By ignoring self-provision, which is primarily from groundwater, the State is not only missing a tremendous opportunity but is jeopardizing the water security of future generations. Full article

GOWARE (transnational Guide toward an Optimal WAter REgime) represents a Decision Support Tool (DST) developed to support the implementation of innovative Best Management Practices (BMPs) for drinking water protection and flood/drought risk mitigation. The tool is one of the main outputs of the PROLINE-CE Project, an EU project funded within the Interreg Central Europe (CE) Programme (2014–2020). The aim of this paper is illustrating the design and the methodological approaches proposed for the operative development of the tool. Furthermore, the paper provides the results of a number of tests carried out to evaluate the understandability of the analysis’s processes and assessing the stakeholders’ acceptance. Specifically, GOWARE-DST has been developed for supporting single users or groups of users in the decision-making process. The tool has been provided with a catalogue of 92 BMPs to handle water issues in different land use contexts. The selection of practices suitable for addressing the specific user’s requirements is supported by the Analytic Hierarchy Process, a method that allows filtering a subset of BMPs by accounting for the relative importance that the user assigns to each characterizing criterion. GOWARE-DST represents an innovative tool for supporting users at different levels of planning (operational and strategic) by promoting sustainable land and water management and defining long-term governance activities. Full article

Episodic coastal hazards associated to sea storms are responsible for sudden and intense changes in coastal morphology. Climate change and local anthropogenic activities such as river regulation and urban growth are raising risk levels in coastal hotspots, like low-lying areas of river deltas. This urges to revise present management strategies to guarantee their future sustainability, demanding a detailed diagnostic of the hazard evolution. In this paper, flooding and erosion under current and future conditions have been assessed at local scale at the urban area of Riumar, a touristic enclave placed at the Ebro Delta (Spain). Process-based models have been used to address the interaction between beach morphology and storm waves, as well as the influence of coastal environment complexity. Storm waves have been propagated with SWAN wave model and have provided the forcings for XBeach, a 2DH hydro-morphodynamic model. Results show that future trends in sea level rise and wave forcing produce non-linear variations of the flooded area and the volume of mobilized sediment resulting from marine storms. In particular, the balance between flooding and sediment transport will shift depending on the relative sea level. Wave induced flooding and long-shore sand transport seem to be diminished in the future, whereas static sea level flooding and cross-shore sediment transport are exacerbated. Therefore, the characterization of tipping points in the coastal response can help to develop robust and adaptive plans to manage climate change impact in sandy wave dominated coasts with a low-lying hinterland and a complex shoreline morphology. Full article

This study was carried out to examine the impact of an artificial recharge site on groundwater level and salinity using treated domestic wastewater for the Korba aquifer (north eastern Tunisia). The site is located in a semi-arid region affected by seawater intrusion, inducing an increase in groundwater salinity. Investigation of the subsurface enabled the identification of suitable areas for aquifer recharge mainly composed of sand formations. Groundwater flow and solute transport models (MODFLOW and MT3DMS) were then setup and calibrated for steady and transient states from 1971 to 2005 and used to assess the impact of the artificial recharge site. Results showed that artificial recharge, with a rate of 1500 m³/day and a salinity of 3.3 g/L, could produce a recovery in groundwater level by up to 2.7 m and a reduction in groundwater salinity by as much as 5.7 g/L over an extended simulation period. Groundwater monitoring for 2007–2014, used for model validation, allowed one to confirm that the effective recharge, reaching the water table, is less than the planned values. Full article

Food and water are at the heart of sustainable development. Roof-harvested rainwater kept in rainwater storage systems (RSS) and used in household agriculture (HA) has the potential to increase yields and supplement household nutrition. Combined systems may contribute to at least eight of the United Nations’ 17 Sustainable Development Goals (SDGs). In this paper, a daily analysis tool, ERain, is used to assess what area of vegetables can be reliably irrigated by roof-harvested rainwater. A socio-economic context is built around an orphanage in the semi-humid region of Nakuru, Kenya. Comparisons are made with the semi-arid region of East Pokot. A 225 kL closed masonry tank and a 1 ML open reservoir with an additional 8 kL/day of recycled water entering are analyzed for various roof sizes. The 225 kL RSS connected to 1000 m² of roof and irrigating 1000 m² could increase yields from 1850 to 4200 kg/year in Nakuru. If evaporation was controlled, the 1 mL RSS and recycled water system could support 4000 m² of land, yielding nearly 20,000 kg/year, which is enough to meet the WHO recommended vegetable dietary requirements of the orphanage. A combination of crops, some for consumption and some for sale, could be grown. Full article

Gastrointestinal (GI) illness risks associated with exposure to waters impacted by human and nonhuman fecal sources were estimated using quantitative microbial risk assessment (QMRA). Microbial source tracking (MST) results had identified Escherichia coli (E. coli) contributors to the waterbody as human and unidentified (10%), cattle and domestic animals (25%), and wildlife (65%) in a rural watershed. The illness risks associated with ingestion during recreation were calculated by assigning reference pathogens for each contributing source and using pathogen dose–response relationships. The risk of GI illness was calculated for a specific sampling site with a geometric mean of E. coli of 163 colony forming units (cfu) 100 mL⁻¹, and the recreational standard of E. coli, 126 cfu 100 mL⁻¹. While the most frequent sources of fecal indicator bacteria at the sampling site were nonhuman, the risk of illness from norovirus, the reference pathogen representing human waste, contributed the greatest risk to human health. This study serves as a preliminary review regarding the potential for incorporating results from library-dependent MST to inform a QMRA for recreational waters. The simulations indicated that identifying the sources contributing to the bacterial impairment is critical to estimate the human health risk associated with recreation in a waterbody. Full article

Notwithstanding the widespread use of natural and pre-exchanged zeolites for zootechnical effluent treatment, little attention has been dedicated to the variation in the chemical composition of the treated slurries, besides the effects on their NH₄⁺ content. This paper aimed at elucidating the compositional variations in terms of major and trace elements of a raw pig-slurry (PS) after three sequential treatment cycles (TC) with three different grain sizes of natural and Na-exchanged zeolite-rich volcanic tuffs (natural ZTs and NaZTs). A series of laboratory batch experiments revealed that all ZTs had profoundly influenced the final PS chemical composition. As expected, the NaZTs were more efficient in terms of NH₄⁺ removal than the natural ZTs, reaching almost 60% reduction of the initial content after three TCs. A parallel effect of this efficient removal was the remarkable increase in Na⁺. The Na-forms of ZTs led also to stronger competition with K⁺ ions, resulting in adsorption of this macronutrient and hence in a reduction of the fertilization value of the PS. In terms of heavy metals and other trace elements, all the treatments with ZTs had significantly increased the Li, Ba, Rb, Sr, Ga, and U content in the PS. Full article

Rainwater tanks are increasingly being implemented as part of the integrated urban water management paradigm where all sources of water, including potable, stormwater and recycled, are considered eligible to contribute to the urban water supply. Over the last decade or so, there has been a rapid uptake of rainwater tank systems in urban areas, especially in Australian cities, encouraged through financial incentives, but more importantly, from change in residential building codes effectively mandating the installation of rainwater tanks. Homes with rainwater tanks in Australian cities have increased from 15% to 28% over six years to 2013. These building codes specify certain rainwater tank specifications to achieve a stated rainwater use, and hence potable water savings. These specifications include minimum rainwater tank size, minimum connected roof area, plumbing for internal supply for toilets and washing machines, and external supply for garden watering. These expected potable water savings from households are often factored into regional strategic water planning objectives. Hence if rainwater tanks do not deliver the expected saving due to sub-standard installation and/or poor maintenance, it will have an adverse impact on the regional water plan in the longer term. In this paper, a methodology to assess the effectiveness of a government rainwater tank policy in achieving predicted potable water savings is described and illustrated with a case study from South East Queensland, Australia. It is anticipated that water professionals across the globe should be able to use the same methodology to assess the effectiveness of similar rainwater policies, or indeed any other distributed water saving policy, in their local planning communities. Full article

Geothermal brines can be a resource of energy, freshwater and minerals. Even when rejected after their exploitation to produce energy in a power plant, the brines can be a source of freshwater and minerals, and can have a residual enthalpy that can be recovered to produce additional power. The different reuse scenarios of these wasted brines depend on the composition and temperature at which they must be reinjected into the wells. On this basis, geothermal energy production is a perfect case study to investigate the water–energy nexus and to optimize the integrated energy- and water-production processes. In this paper, two case studies of brine reuse for both energy and water production are presented with the related process analysis, basic design and technical–economic analysis. A methodology to evaluate the exergy efficiency of the processes is presented by analyzing minimum work of separation, the maximum achievable work and the additional primary energy required for integrated production. The novel approach to estimate the process efficiency for integrated geothermal energy and desalination plants is applied to the case studies and discussed in light of literature results. Full article

There is a general agreement on the impact of beaver dams regarding the increasing diversity of habitats and the improvement of the water quality, whereas the retention effect during flood events is still being discussed. In this study, we modeled 12 beaver dam cascade scenarios in two catchments for eight flood events with a two-dimensional (2D) hydrodynamic model. The implementation of the potential cascades in the model is based on the developed three-stage model for predicting location-dependent dam cascades in Bavaria. A Bavaria-wide questionnaire regarding dam occurrences and characteristics in combination with a detailed survey of 51 dams was used to set up a prediction scheme. It was observed that beaver dams are most likely built in rivers with riparian forest, with widths from 2 to 11 m and depths smaller than 1 m. The hydraulic model results showed larger inundation areas (>+300%) for the beaver dam scenarios. There is a noticeable peak attenuation and translation for elevated peak discharges (five times the annual mean discharge: up to ≤13.1% and 2.75 h), but no remarkable effect could be observed for flood events with return periods of more than 2 years. We conclude from the results that beaver dam cascades can have an impact on runoff characteristics, but do not lead to relevant peak reductions during flood events and therefore cannot be counted as flood mitigation measure. Full article

Milk whey processing wastewaters (MWPWs) are characterized by high COD and organic nitrogen content; the concentrations of phosphorus are also relevant. A microalgal-based process was tested at lab scale in order to assess the feasibility of treating MWPW without any dilution or pre-treatment. Different microalgal strains and populations were tested. Based on the obtained results, Scenedesmus acuminatus (SA) and a mixed population (PM) chiefly made of Chlorella, Scenedesmus, and Chlamydomonas spp. were grown in duplicate for 70 days in Plexiglas column photobioreactors (PBRs), fed continuously (2.5 L culture volume, 7 days hydraulic retention time). Nutrient removal, microalgae growth, photosynthetic efficiency, and the composition of microalgal populations in the columns were monitored. At steady state, the microalgal growth was similar for SA and PM. The average removal efficiencies for the main pollutants were: 93% (SA), 94% (PM) for COD; 88% (SA) and 90% (PM) for total N; and 69% (SA) and 73% (PM) for total P. The residual pollution levels in the effluent from the PBRs were low enough to allow their discharge into surface waters; such good results were achieved thanks to the synergy between the microalgae and bacteria in the CO₂ and oxygen production/consumption and in the nitrogen mineralization. Full article

Eutrophication caused by the entry of nutrients into a water body may lead to algal bloom. Russia possesses the world’s second highest supply of renewable freshwater resources and has faced the problem of eutrophication for many years. Nevertheless, as far as we know, no general analysis of Russia’s algal bloom situation has been before carried out. We have analyzed mass media and scientific reports about algal outbreaks from 2016 to 2018, which allowed us to determine the geographical distribution of algal blooms in Russia, as well as the major effects of eutrophication. As a result, we showed that algal blooms happened in all major climate zones and all federal districts. Cyanobacteria are the most frequently reported photosynthetic organisms comprising algal blooms in freshwater reservoirs located in the continental part of Russia and in the Baltic Sea. Dinoflagellate dominated blooms are more characteristic for the coastal parts of the northeastern Pacific Ocean. The largest number of reports comes from the south of the European part of Russia. However, we did not find significant correlations between state statistics data on factors possibly affecting eutrophication (e.g., population, arable land area, fertilizers, livestock, air temperature, etc.) and the number of algal outbreaks in the regions. Mass media analysis showed that algal blooms attract considerable public attention in Russia, which requires the scientific community to actively participate in solving the problem. Full article

Landslides are one of the major natural disasters that Bhutan faces every year. The monsoon season in Bhutan is usually marked by heavy rainfall, which leads to multiple landslides, especially across the highways, and affects the entire transportation network of the nation. The determinations of rainfall thresholds are often used to predict the possible occurrence of landslides. A rainfall threshold was defined along Samdrup Jongkhar–Trashigang highway in eastern Bhutan using cumulated event rainfall and antecedent rainfall conditions. Threshold values were determined using the available daily rainfall and landslide data from 2014 to 2017, and validated using the 2018 dataset. The threshold determined was used to estimate temporal probability using a Poisson probability model. Finally, a landslide susceptibility map using the analytic hierarchy process was developed for the highway to identify the sections of the highway that are more susceptible to landslides. The accuracy of the model was validated using the area under the receiver operating characteristic curves. The results presented here may be regarded as a first step towards understanding of landslide hazards and development of an early warning system for a region where such studies have not previously been conducted. Full article

Contents of soil organic carbon (SOC), gypsum, CaCO₃, and quartz, among others, were analyzed and related to reflectance features in visible and near-infrared (VIS/NIR) range, using partial least square regression (PLSR) in ParLes software. Soil samples come from a sloping olive grove managed by frequent tillage in a gypsiferous area of Central Spain. Samples were collected in three different layers, at 0–10, 10–20 and 20–30 cm depth (IPCC guidelines for Greenhouse Gas Inventories Programme in 2006). Analyses were performed by C Loss-On-Ignition, X-ray diffraction and water content by the Richards plates method. Significant differences for SOC, gypsum, and CaCO₃ were found between layers; similarly, soil reflectance for 30 cm depth layers was higher. The resulting PLSR models (60 samples for calibration and 30 independent samples for validation) yielded good predictions for SOC (R² = 0.74), moderate prediction ability for gypsum and were not accurate for the rest of rest of soil components. Importantly, SOC content was related to water available capacity. Soils with high reflectance features held c.a. 40% less water than soils with less reflectance. Therefore, higher reflectance can be related to degradation in gypsiferous soil. The starting point of soil degradation and further evolution could be established and mapped through remote sensing techniques for policy decision making. Full article

Growing drought hazard and water demand for agriculture, ecosystem conservation, and tourism in the Hungarian Drava river floodplain call for novel approaches to maintain wetland habitats and enhance agricultural productivity. Floodplain rehabilitation should be viewed as a complex landscape ecological issue which, beyond water management goals to relieve water deficit, ensures a high level of provision for a broad range of ecosystem services. This paper explores the hydrological feasibility of alternative water management, i.e., the restoration of natural reservoirs (abandoned paleochannels) to mitigate water shortage problems. To predict the efficiency of the project, an integrated surface water (Wetspass-M) and groundwater model (MODFLOW-NWT) was developed and calibrated with an eight-year data series. Different management scenarios for two natural reservoirs were simulated with filling rates ranging from 0.5 m³ s⁻¹ to 1.5 m³ s⁻¹. In both instances, a natural reservoir with a feeding rate of 1 m³ s⁻¹ was found to be the best scenario. In this case 14 days of filling are required to reach the possible maximum reservoir stage of +2 m. The first meter rise increases the saturation of soil pores and the second creates an open surface water body. Two filling periods per year, each lasting for around 180 days, are required. The simulated water balance shows that reservoir–groundwater interactions are mainly governed by the inflow into and outflow from the reservoir. Such an integrated management scheme is applicable for floodplain rehabilitation in other regions with similar hydromorphological conditions and hazards, too. Full article

Groundwater contamination is a major problem in the Gaza Strip. In this study we investigate the groundwater quality in the Dier al-Balah Governorate. Water samples were collected from 19 municipal wells in April 2009 and April 2014 and analyzed for physio-chemical parameters (pH, TDS, Ca²⁺, Mg²⁺, Na⁺, K⁺, Cl⁻, SO₄^2–, HCO₃⁻ and NO₃⁻). The aim of the research is to determine the groundwater quality and to produce groundwater quality maps using the water quality index (WQI) method and geostatistical analysis. The results show that all water samples are very saline due to the intrusion of Mediterranean seawater in the coastal aquifer. Differences in chemical composition between 2009 and 2014 indicate that about 1% more seawater was mixed with the groundwater in this period. The majority of the observed chemical parameters of all wells are well above the WHO water quality standards and all WQI values indicate that the water quality is problematic. The spatial variation of the WQI scores is modelled by a deterministic component expressing a linear dependence on the distance to the coastline and a stochastic residual described by an exponential variogram with a practical range of 3000 m. The mapping of the WQI scores and derived water quality classes is achieved through regression-kriging. The results indicate that the groundwater in a large area along the coastline is unsuitable for human consumption and comparison of the maps of 2009 and 2014 shows that this region further expanded by about 700 m inland in a period of 5 years. The results of this study are worrying, but they also contribute to a better understanding of the factors that determine the groundwater quality and can help authorities and stakeholders with sustainable development. Full article

Impulse waves generated by landslides falling into reservoirs may lead to overtopping of a dam and, in turn, to flooding of the downstream area. In the case of an embankment dam, the overtopping may lead to erosion of the downstream slope, ultimately resulting in breaching and complete failure with consequent further hazardous release of water to the downstream area. This research deals with the overtopping process of a dam due to landslide generated waves in a three-dimensional (3D) physical scale model setup. Experiments have been conducted with varying the slide, reservoir, and dam parameters. The primary focus is on investigating the feasibility of employing the steady state weir equation in order to predict the overtopping discharge over a dam crest due to landslide generated waves. Calibration and validation of the coefficient of discharge values for the different dam section are conducted for the specified model setup. Accordingly, a two-step calculation procedure is presented for predicting the overtopping discharge based on the maximum overtopping depth values. Hence, for the fixed setup, which includes a constant slope angle of the landslide surface, a predictive equation for maximum overtopping depth is proposed, based on slide volume, slide release height, still water depth, upstream dam slope angle, and dam height. The relative slide volume and relative still water depth both seem to have a significant effect on the relative overtopping depth. Full article

Best management practices (BMPs) are an effective way to control water pollution. However, identification of the optimal distribution and cost-effect of BMPs provides a great challenge for watershed policy makers. In this paper, a semi-distributed, low-data, and robust watershed model, the Revised Generalized Watershed Loading Function (RGWLF), is improved by adding the pollutant attenuation process in the river channel and a bank filter strips reduction function. Three types of pollution control measures—point source wastewater treatment, bank filter strips, and converting farmland to forest—are considered, and the cost of each measure is determined. Furthermore, the RGWLF watershed model is coupled with a widely recognized multi-objective optimization algorithm, the non-dominated sorting genetic algorithm II (NSGAII), the combination of which is applied in the Luanhe watershed to search for spatial BMPs for dissolved nitrogen (DisN). Fifty scenarios were finally selected from numerous possibilities and the results indicate that, at a minimum cost of 9.09 × 10⁷ yuan, the DisN load is 3.1 × 10⁷ kg and, at a maximum cost of 1.77 × 10⁸ yuan, the total dissolved nitrogen load is 1.31 × 10⁷ kg; with the no-measures scenario, the DisN load is 4.05 × 10⁷ kg. This BMP optimization model system could assist decision-makers in determining a scientifically comprehensive plan to realize cost-effective goals for the watershed. Full article

Risk of flash floods is currently an important problem in many parts of Vietnam. In this study, we used four machine-learning methods, namely Kernel Logistic Regression (KLR), Radial Basis Function Classifier (RBFC), Multinomial Naïve Bayes (NBM), and Logistic Model Tree (LMT) to generate flash flood susceptibility maps at the minor part of Nghe An province of the Center region (Vietnam) where recurrent flood problems are being experienced. Performance of these four methods was evaluated to select the best method for flash flood susceptibility mapping. In the model studies, ten flash flood conditioning factors, namely soil, slope, curvature, river density, flow direction, distance from rivers, elevation, aspect, land use, and geology, were chosen based on topography and geo-environmental conditions of the site. For the validation of models, the area under Receiver Operating Characteristic (ROC), Area Under Curve (AUC), and various statistical indices were used. The results indicated that performance of all the models is good for generating flash flood susceptibility maps (AUC = 0.983–0.988). However, performance of LMT model is the best among the four methods (LMT: AUC = 0.988; KLR: AUC = 0.985; RBFC: AUC = 0.984; and NBM: AUC = 0.983). The present study would be useful for the construction of accurate flash flood susceptibility maps with the objectives of identifying flood-susceptible areas/zones for proper flash flood risk management. Full article

The isotope composition of precipitation has been monitored in monthly precipitation at Zagreb, Croatia, since 1976. Here, we present a statistical analysis of available long-term isotope data (³H activity concentration, δ²H, δ¹⁸O, and deuterium excess) and compare them to basic meteorological data. The aim was to see whether isotope composition reflected observed climate changes in Zagreb: a significant increase in the annual air temperature and larger variations in the precipitation amount. Annual mean δ¹⁸O and δ²H values showed an increase of 0.017‰ and 0.14‰ per year, respectively, with larger differences in monthly mean values in the first half of the year than in the second half. Mean annual d-excess remained constant over the whole long-term period, with a tendency for monthly mean d-excess values to decrease in the first half of the year and increase in the second half due to the influence of air masses originating from the eastern Mediterranean. Changes in the stable isotope composition of precipitation thus resembled changes in the temperature, the circulation pattern of air masses, and the precipitation regime. A local meteoric water line was obtained using different regression methods, which did not result in significant differences between nonweighted and precipitation-weighted slope and intercept values. Deviations from the Global Meteoric Water Line GMWL (lower slopes and intercepts) were observed in two recent periods and could be explained by changes in climate parameters. The temperature gradient of δ¹⁸O was 0.33‰/°C. The tritium activity concentrations in precipitation showed slight decreases during the last two decades, and the mean A in the most recent period, 2012–2018, was 7.6 ± 0.8 Tritium Units (TU). Full article

Characteristics of hydrodynamic forces and flow fields around the semi-submersible platform induced by the internal solitary wave (ISW) propagation were investigated in a 3D numerical wave tank. Good agreements between numerical results and experimental data of forces and torque on the platform were achieved. The hydrodynamic loads increased and decreased with the increases in the ISW amplitude and fluid depth ratio, respectively. The pressure mainly contributed to the force on the platform. The horizontal forces on bracings were negligible. Almost all the vertical forces on the platform were derived from those on pontoons. The horizontal force and torque on the platform increased with the increases in the angle between the platform symmetrical axis and the ISW propagation direction. The platform subjected the maximum vertical force when the angle was 0°. There were obvious velocity reductions around the platform during the ISW propagation, as visible vortexes shedding around the platform could be observed. Complexities of the distributions of flow fields around the platforms located at the 30°- and 60°-direction were greater than those around the platforms located at the 0°- and 90°-direction. Flow fields around the same kind components of each platform located at different angles were similar. Full article

The paper examines the extent, nature, and factors affecting women’s involvement in participatory irrigation institutions of eastern India. Effective participatory water institutions are urgently needed to improve water management in eastern India, and a significant aspect of this is the involvement of women. There is inadequate representation, participation, and involvement of women in most water institutions. From the participatory and social point of view, this is a significant concern. The relevant data are obtained from the states of Assam and Bihar through a focused survey administered to 109 women in 30 water institutions, and a larger farmer-institutional survey covering 510 households and 51 water institutions. The research examines the extent and nature of the involvement of women in these institutions, as well as in farm decision-making, and the factors that prevent or foster their participation. Additionally, it examines the gender congruence in views regarding water institution activities and their performance, and the perceived benefits of formal involvement of women. The results show that their inclusion is very low (except required inclusion in Bihar), and the concerns of women are usually not being taken into account. Women are involved in farming and water management decisions jointly with men but not independently. Findings indicate that the views of women and men differ on many aspects, and so their inclusion is important. Responses indicate that if women participate formally in water user associations, it would enhance their social and economic standing, achieve greater gender balance, expand their awareness of water management, and contribute to better decision-making in the water institutions. Full article

Climate change could have dire effects on hydropower systems, especially in southwest China, where hydropower dominates the regional power system. This study examines two large cascade hydropower systems in Yunnan province in southwest China for 10 climate change projections made with 5 global climate models (GCMs) and 2 representative concentration pathways (RCPs) under Coupled Model Intercomparison Project Phase 5 (CMIP5). First, a back propagation neural network rain-runoff model is built for each hydropower station to estimate inflows with climate change. Then, a progressive optimality algorithm maximizes hydropower generation for each projection. The results show generation increasing in each GCM projection, but increasing more in GCMs under scenario RCP8.5. However, yearly generation fluctuates more: generation decreases dramatically with potential for electricity shortages in dry years and more electricity as well as spill during wet years. Average annual spill, average annual inflow and average storage have similar trends. The analysis indicates that a planned large dam on the upper Jinsha River would increase seasonal regulation ability, increase hydropower generation, and decrease spill. Increased turbine capacity increases generation slightly and decreases spill for the Lancang River. Results from this study demonstrate effects of climate change on hydropower systems and identify which watersheds might be more vulnerable, along with some actions that could help adapt to climate change. Full article

Runoff modeling is one of the key challenges in the field of hydrology. Various approaches exist, ranging from physically based over conceptual to fully data driven models. In this paper, we propose a data driven approach using the state-of-the-art Long-Short-Term-Memory (LSTM) network. The proposed model was applied in the Poyang Lake Basin (PYLB) and its performance was compared with an Artificial Neural Network (ANN) and the Soil & Water Assessment Tool (SWAT). We first tested the impacts of the number of previous time step (window size) in simulation accuracy. Results showed that a window in improper large size will dramatically deteriorate the model performance. In terms of PYLB, a window size of 15 days might be appropriate for both accuracy and computational efficiency. We then trained the model with 2 different input datasets, namely, dataset with precipitation only and dataset with all available meteorological variables. Results demonstrate that although LSTM with precipitation data as the only input can achieve desirable results (where the NSE ranged from 0.60 to 0.92 for the test period), the performance can be improved simply by feeding the model with more meteorological variables (where NSE ranged from 0.74 to 0.94 for the test period). Moreover, the comparison results with the ANN and the SWAT showed that the ANN can get comparable performance with the SWAT in most cases whereas the performance of LSTM is much better. The results of this study underline the potential of the LSTM for runoff modeling especially for areas where detailed topographical data are not available. Full article