Water

15 pages, 4595 KiB

Open AccessEditor’s ChoiceArticle

Removal of Pharmaceuticals, Toxicity and Natural Fluorescence by Ozonation in Biologically Pre-Treated Municipal Wastewater, in Comparison to Subsequent Polishing Biofilm Reactors

by Kai Tang, Gordon T. H. Ooi, Aikaterini Spiliotopoulou, Kamilla M. S. Kaarsholm, Kim Sundmark, Bianca Florian, Caroline Kragelund, Kai Bester and Henrik R. Andersen

Water 2020, 12(4), 1059; https://doi.org/10.3390/w12041059 - 8 Apr 2020

Cited by 7 | Viewed by 3687

Abstract

Ozonation followed by a polishing moving bed biofilm reactor (MBBR) was implemented in pilot and laboratory to remove the residual pharmaceuticals and toxicity from wastewater effluent, which was from a pilot hybrid system of MBBR and activated sludge, receiving municipal wastewater. The delivered [...] Read more.

Ozonation followed by a polishing moving bed biofilm reactor (MBBR) was implemented in pilot and laboratory to remove the residual pharmaceuticals and toxicity from wastewater effluent, which was from a pilot hybrid system of MBBR and activated sludge, receiving municipal wastewater. The delivered ozone dosages achieving 90% pharmaceutical removal were determined both in pilot and laboratory experiments and they were normalised to dissolved organic carbon (DOC), illustrating our findings were comparable with previously published literature. During wastewater ozonation, the intensity of natural fluorescence was found to be greatly associated with the concentrations of the studied pharmaceuticals. In pilot experiments, toxicity, measured by Vibrio fischeri, increased after ozonation at delivered ozone dosages at 0.38–0.47 mg O₃/mg DOC and was completely removed by the subsequent polishing MBBR. Laboratory experiments verified that the polishing MBBR was able to remove the toxicity produced by the ozonation. Full article

(This article belongs to the Special Issue Hybrid Systems Using Different Technologies for Wastewater Treatment and Reuse)

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17 pages, 639 KiB

Open AccessEditor’s ChoiceArticle

A Rentier State under Blockade: Qatar’s Water-Energy-Food Predicament from Energy Abundance and Food Insecurity to a Silent Water Crisis

by Hussam Hussein and Laurent A. Lambert

Water 2020, 12(4), 1051; https://doi.org/10.3390/w12041051 - 8 Apr 2020

Cited by 27 | Viewed by 13546

Abstract

This article investigates Qatar’s sustainability crisis of the high levels of water, electricity and food use. The high levels of consumption have been enabled by Qatar’s significant hydrocarbons wealth, a generous rentier state’s redistributive water governance, and structural dependence on imported food and [...] Read more.

This article investigates Qatar’s sustainability crisis of the high levels of water, electricity and food use. The high levels of consumption have been enabled by Qatar’s significant hydrocarbons wealth, a generous rentier state’s redistributive water governance, and structural dependence on imported food and food production subsidies. The water crisis is silent because it does not generate supply disruptions nor any public discontentment. The geopolitical blockade Qatar is experiencing sparked discussions in policy circles on the best ways to ensure food security, but has only exacerbated its water insecurity. The blockade makes more urgent than ever the necessity to maximize and increase synergies among different sectors. Full article

(This article belongs to the Section Water, Agriculture and Aquaculture)

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19 pages, 1853 KiB

Open AccessEditor’s ChoiceReview

Drinking Water Temperature around the Globe: Understanding, Policies, Challenges and Opportunities

by Claudia Agudelo-Vera, Stefania Avvedimento, Joby Boxall, Enrico Creaco, Henk de Kater, Armando Di Nardo, Aleksandar Djukic, Isabel Douterelo, Katherine E. Fish, Pedro L. Iglesias Rey, Nenad Jacimovic, Heinz E. Jacobs, Zoran Kapelan, Javier Martinez Solano, Carolina Montoya Pachongo, Olivier Piller, Claudia Quintiliani, Jan Ručka, Ladislav Tuhovčák and Mirjam Blokker

Water 2020, 12(4), 1049; https://doi.org/10.3390/w12041049 - 7 Apr 2020

Cited by 72 | Viewed by 14328

Abstract

Water temperature is often monitored at water sources and treatment works; however, there is limited monitoring of the water temperature in the drinking water distribution system (DWDS), despite a known impact on physical, chemical and microbial reactions which impact water quality. A key [...] Read more.

Water temperature is often monitored at water sources and treatment works; however, there is limited monitoring of the water temperature in the drinking water distribution system (DWDS), despite a known impact on physical, chemical and microbial reactions which impact water quality. A key parameter influencing drinking water temperature is soil temperature, which is influenced by the urban heat island effects. This paper provides critique and comprehensive summary of the current knowledge, policies and challenges regarding drinking water temperature research and presents the findings from a survey of international stakeholders. Knowledge gaps as well as challenges and opportunities for monitoring and research are identified. The conclusion of the study is that temperature in the DWDS is an emerging concern in various countries regardless of the water source and treatment, climate conditions, or network characteristics such as topology, pipe material or diameter. More research is needed, especially to determine (i) the effect of higher temperatures, (ii) a legislative limit on temperature and (iii) measures to comply with this limit. Full article

(This article belongs to the Special Issue Water Quality in Drinking Water Distribution Systems)

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18 pages, 6766 KiB

Open AccessEditor’s ChoiceArticle

Sociohydrologic Systems Thinking: An Analysis of Undergraduate Students’ Operationalization and Modeling of Coupled Human-Water Systems

by Diane Lally and Cory T. Forbes

Water 2020, 12(4), 1040; https://doi.org/10.3390/w12041040 - 7 Apr 2020

Cited by 14 | Viewed by 3762

Abstract

One of the keys to science and environmental literacy is systems thinking. Learning how to think about the interactions between systems, the far-reaching effects of a system, and the dynamic nature of systems are all critical outcomes of science learning. However, students need [...] Read more.

One of the keys to science and environmental literacy is systems thinking. Learning how to think about the interactions between systems, the far-reaching effects of a system, and the dynamic nature of systems are all critical outcomes of science learning. However, students need support to develop systems thinking skills in undergraduate geoscience classrooms. While systems thinking-focused instruction has the potential to benefit student learning, gaps exist in our understanding of students’ use of systems thinking to operationalize and model SHS, as well as their metacognitive evaluation of systems thinking. To address this need, we have designed, implemented, refined, and studied an introductory-level, interdisciplinary course focused on coupled human-water, or sociohydrologic, systems. Data for this study comes from three consecutive iterations of the course and involves student models and explanations for a socio-hydrologic issue (n = 163). To analyze this data, we counted themed features of the drawn models and applied an operationalization rubric to the written responses. Analyses of the written explanations reveal statistically-significant differences between underlying categories of systems thinking (F(5, 768) = 401.6, p < 0.05). Students were best able to operationalize their systems thinking about problem identification (M = 2.22, SD = 0.73) as compared to unintended consequences (M = 1.43, SD = 1.11). Student-generated systems thinking models revealed statistically significant differences between system components, patterns, and mechanisms, F(2, 132) = 3.06, p < 0.05. Students focused most strongly on system components (M = 13.54, SD = 7.15) as compared to related processes or mechanisms. Qualitative data demonstrated three types of model limitation including scope/scale, temporal, and specific components/mechanisms/patterns excluded. These findings have implications for supporting systems thinking in undergraduate geoscience classrooms, as well as insight into links between these two skills. Full article

(This article belongs to the Special Issue Water Literacy and Education)

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30 pages, 17371 KiB

Open AccessEditor’s ChoiceReview

Recent Trends in Removal Pharmaceuticals and Personal Care Products by Electrochemical Oxidation and Combined Systems

by Khanh Chau Dao, Chih-Chi Yang, Ku-Fan Chen and Yung-Pin Tsai

Water 2020, 12(4), 1043; https://doi.org/10.3390/w12041043 - 7 Apr 2020

Cited by 46 | Viewed by 6282

Abstract

Due to various potential toxicological threats to living organisms even at low concentrations, pharmaceuticals and personal care products in natural water are seen as an emerging environmental issue. The low efficiency of removal of pharmaceuticals and personal care products by conventional wastewater treatment [...] Read more.

Due to various potential toxicological threats to living organisms even at low concentrations, pharmaceuticals and personal care products in natural water are seen as an emerging environmental issue. The low efficiency of removal of pharmaceuticals and personal care products by conventional wastewater treatment plants calls for more efficient technology. Research on advanced oxidation processes has recently become a hot topic as it has been shown that these technologies can effectively oxidize most organic contaminants to inorganic carbon through mineralization. Among the advanced oxidation processes, the electrochemical advanced oxidation processes and, in general, electrochemical oxidation or anodic oxidation have shown good prospects at the lab-scale for the elimination of contamination caused by the presence of residual pharmaceuticals and personal care products in aqueous systems. This paper reviewed the effectiveness of electrochemical oxidation in removing pharmaceuticals and personal care products from liquid solutions, alone or in combination with other treatment processes, in the last 10 years. Reactor designs and configurations, electrode materials, operational factors (initial concentration, supporting electrolytes, current density, temperature, pH, stirring rate, electrode spacing, and fluid velocity) were also investigated. Full article

(This article belongs to the Special Issue Advanced Oxidation Processes for Water and Wastewater Treatment)

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20 pages, 5756 KiB

Open AccessEditor’s ChoiceArticle

Climate Change Impact on Surface Water and Groundwater Recharge in Northern Thailand

by Chanchai Petpongpan, Chaiwat Ekkawatpanit and Duangrudee Kositgittiwong

Water 2020, 12(4), 1029; https://doi.org/10.3390/w12041029 - 4 Apr 2020

Cited by 31 | Viewed by 8598

Abstract

Climate change is progressing and is now one of the most important global challenges for humanities. Water resources management is one of the key challenges to reduce disaster risk. In Northern Thailand, flood and drought have always occurred because of the climate change [...] Read more.

Climate change is progressing and is now one of the most important global challenges for humanities. Water resources management is one of the key challenges to reduce disaster risk. In Northern Thailand, flood and drought have always occurred because of the climate change impact and non-systematic management in the conjunctive use of both sources of water. Therefore, this study aims to assess the climate change impact on surface water and groundwater of the Yom and Nan river basins, located in the upper part of Thailand. The surface water and groundwater regimes are generated by a fully coupled SWAT-MODFLOW model. The future climate scenarios are considered from the Representative Concentration Pathways (RCPs) 2.6 and 8.5, presented by the Coupled Model Intercomparison Project Phase 5 (CMIP5), in order to mainly focus on the minimum and maximum Green House Gas (GHG) emissions scenarios during the near future (2021–2045) periods. The results show that the average annual air temperature rises by approximately 0.5–0.6 °C and 0.9–1.0 °C under the minimum (RCP 2.6) and maximum (RCP 8.5) GHG emission scenarios, respectively. The annual rainfall, obtained from both scenarios, increased by the same range of 20–200 mm/year, on average. The summation of surface water (water yield) and groundwater recharge (water percolation) in the Yom river basin decreased by 443.98 and 316.77 million m³/year under the RCPs 2.6 and 8.5, respectively. While, in the Nan river basin, it is projected to increase by 355 million m³/year under RCP 2.6 but decrease by 20.79 million m³/year under RCP 8.5. These quantitative changes can directly impact water availability when evaluating the water demand for consumption, industry, and agriculture. Full article

(This article belongs to the Special Issue Modeling Global Change Impacts on Water Resources: Selected Papers from the 2019/2020 SWAT International Conferences)

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18 pages, 3063 KiB

Open AccessEditor’s ChoiceArticle

Assessing Inhomogeneities in Extreme Annual Rainfall Data Series by Multifractal Approach

by Amanda P. García-Marín, Javier Estévez, Renato Morbidelli, Carla Saltalippi, José Luis Ayuso-Muñoz and Alessia Flammini

Water 2020, 12(4), 1030; https://doi.org/10.3390/w12041030 - 4 Apr 2020

Cited by 14 | Viewed by 3307

Abstract

Testing the homogeneity in extreme rainfall data series is an important step to be performed before applying the frequency analysis method to obtain quantile values. In this work, six homogeneity tests were applied in order to check the existence of break points in [...] Read more.

Testing the homogeneity in extreme rainfall data series is an important step to be performed before applying the frequency analysis method to obtain quantile values. In this work, six homogeneity tests were applied in order to check the existence of break points in extreme annual 24-h rainfall data at eight stations located in the Umbria region (Central Italy). Two are parametric tests (the standard normal homogeneity test and Buishand test) whereas the other four are non-parametric (the Pettitt, Sequential Mann–Kendal, Mann–Whitney U, and Cumulative Sum tests). No break points were detected at four of the stations analyzed. Where inhomogeneities were found, the multifractal approach was applied in order to check if they were real or not by comparing the split and whole data series. The generalized fractal dimension functions D_q and the multifractal spectra f(α) were obtained, and their main parameters were used to decide whether or not a break point existed. Full article

(This article belongs to the Section Hydrology)

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27 pages, 4380 KiB

Open AccessEditor’s ChoiceArticle

Tree-Based Modeling Methods to Predict Nitrate Exceedances in the Ogallala Aquifer in Texas

by Venkatesh Uddameri, Ana Luiza Bessa Silva, Sreeram Singaraju, Ghazal Mohammadi and E. Annette Hernandez

Water 2020, 12(4), 1023; https://doi.org/10.3390/w12041023 - 3 Apr 2020

Cited by 20 | Viewed by 4042

Abstract

The performance of four tree-based classification techniques—classification and regression trees (CART), multi-adaptive regression splines (MARS), random forests (RF) and gradient boosting trees (GBT) were compared against the commonly used logistic regression (LR) analysis to assess aquifer vulnerability in the Ogallala Aquifer of Texas. [...] Read more.

The performance of four tree-based classification techniques—classification and regression trees (CART), multi-adaptive regression splines (MARS), random forests (RF) and gradient boosting trees (GBT) were compared against the commonly used logistic regression (LR) analysis to assess aquifer vulnerability in the Ogallala Aquifer of Texas. The results indicate that the tree-based models performed better than the logistic regression model, as they were able to locally refine nitrate exceedance probabilities. RF exhibited the best generalizable capabilities. The CART model did better in predicting non-exceedances. Nitrate exceedances were sensitive to well depths—an indicator of aquifer redox conditions, which, in turn, was controlled by alkalinity increases brought forth by the dissolution of calcium carbonate. The clay content of soils and soil organic matter, which serve as indicators of agriculture activities, were also noted to have significant influences on nitrate exceedances. Likely nitrogen releases from confined animal feedlot operations in the northeast portions of the study area also appeared to be locally important. Integrated soil, hydrogeological and geochemical datasets, in conjunction with tree-based methods, help elucidate processes controlling nitrate exceedances. Overall, tree-based models offer flexible, transparent approaches for mapping nitrate exceedances, identifying underlying mechanisms and prioritizing monitoring activities. Full article

(This article belongs to the Section Hydrology)

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18 pages, 5670 KiB

Open AccessEditor’s ChoiceArticle

Fluid-Structure Interaction Response of a Water Conveyance System with a Surge Chamber during Water Hammer

by Qiang Guo, Jianxu Zhou, Yongfa Li, Xiaolin Guan, Daohua Liu and Jian Zhang

Water 2020, 12(4), 1025; https://doi.org/10.3390/w12041025 - 3 Apr 2020

Cited by 11 | Viewed by 2960

Abstract

Fluid–structure interaction (FSI) is a frequent and unstable inherent phenomenon in water conveyance systems. Especially in a system with a surge chamber, valve closing and the subsequent water level oscillation in the surge chamber are the excitation source of the hydraulic transient process. [...] Read more.

Fluid–structure interaction (FSI) is a frequent and unstable inherent phenomenon in water conveyance systems. Especially in a system with a surge chamber, valve closing and the subsequent water level oscillation in the surge chamber are the excitation source of the hydraulic transient process. Water-hammer-induced FSI has not been considered in preceding research, and the results without FSI justify further investigations. In this study, an FSI eight-equation model is presented to capture its influence. Both the elbow pipe and surge chamber are treated as boundary conditions, and solved using the finite volume method (FVM). After verifying the feasibility of using FVM to solve FSI, friction, Poisson, and junction couplings are discussed in detail to separately reveal the influence of a surge chamber, tow elbows, and a valve on FSI. Results indicated that the major mechanisms of coupling are junction coupling and Poisson coupling. The former occurs in the surge chamber and elbows. Meanwhile, a stronger pressure pulsation is produced at the valve, resulting in a more complex FSI response in the water conveyance system. Poisson coupling and junction coupling are the main factors contributing to a large amount of local transilience emerging on the dynamic pressure curves. Moreover, frictional coupling leads to the lower amplitudes of transilience. These results indicate that the transilience is induced by the water hammer–structure interaction and plays important roles in the orifice optimization in the surge chamber. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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18 pages, 8658 KiB

Open AccessEditor’s ChoiceArticle

The Impact of Submerged Breakwaters on Sediment Distribution along Marsh Boundaries

by Iacopo Vona, Matthew W. Gray and William Nardin

Water 2020, 12(4), 1016; https://doi.org/10.3390/w12041016 - 2 Apr 2020

Cited by 30 | Viewed by 7269

Abstract

Human encroachment and development on coastlines have led to greater amounts of armoring of shorelines. Breakwaters are a common feature along coastlines, which are used to dampen wave energy and protect shorelines from flash floods or overwash events. Although common, their effects on [...] Read more.

Human encroachment and development on coastlines have led to greater amounts of armoring of shorelines. Breakwaters are a common feature along coastlines, which are used to dampen wave energy and protect shorelines from flash floods or overwash events. Although common, their effects on sediment transport and marsh geomorphology are poorly understood. To address this gap, our study quantifies the effects of breakwaters on sediment transport and marsh evolution under different wave regimes using Delft3D-SWAN, a dynamic geomorphodynamic numerical model. Model configurations used the same numerical domain, but scenarios had different sediments, waves, tides, basin slopes and breakwater distances from the shoreline to explore how waves and tidal currents shape coastal margins. Model results suggested breakwaters were responsible for an average wave damping between 10–50%, proportional to the significant wave height across all modeled scenarios. Shear stress at the beginning of the marsh and the volume of sediment deposited at the end of the simulation (into the marsh behind the breakwater) increased on average between 20–40%, proportional to the slope and distance of the breakwater from the shoreline. Sediment trapping, defined as the ratio between the volume of sediment housed into the salt marsh behind and away from the breakwater, was found to be less than 1 from most model runs. Study results indicated that breakwaters are advantageous for wave breaking to protect shorelines from the wave’s energy, however, they might also be an obstacle for sediment transport, negatively affecting nourishment processes, and, consequently, impeded long-term salt marsh survival. Identifying a balance between waves dampening and shoreline nourishment should be considered in the design and implementation of these structures. Full article

(This article belongs to the Special Issue Advances in the Study of Coastal Resilience, Hydrodynamic Modelling and Coastal Monitoring)

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15 pages, 2187 KiB

Open AccessEditor’s ChoiceArticle

Model Analysis and System Parameters Investigation for Transient Wave in a Pump–Pipe–Valve System

by Zubin Liu, Dingyi Pan, Fengzhong Qu and Jianxin Hu

Water 2020, 12(4), 1014; https://doi.org/10.3390/w12041014 - 2 Apr 2020

Viewed by 2333

Abstract

The frequency responses of the transient wave propagating in a pump–pipe–valve system are studied with the system transfer matrix analysis (STMA) method. Being different to that in the reservoir–pipe–valve system, the transient wave is used as a long-distance communication technology in the pump–pipe–valve [...] Read more.

The frequency responses of the transient wave propagating in a pump–pipe–valve system are studied with the system transfer matrix analysis (STMA) method. Being different to that in the reservoir–pipe–valve system, the transient wave is used as a long-distance communication technology in the pump–pipe–valve system, and very few works have been done on the model analysis and strategies to control the behavior of the oscillation signal of the pipe pressure. The theoretic solutions are studied with three internal friction models: frictionless, steady friction, and unsteady friction. The dimensionless parameter of the valve signal intensity (VSI) is proposed, and it is found to be a key factor affecting the quality of the wave propagation in the pipe. A larger pressure oscillation at the upstream side results when the VSI is smaller than one, whereas a more uniform amplitude for the resonances and anti-resonances is obtained when VSI approaches one. Some feasible suggestions are provided to obtain high quality wave signals. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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13 pages, 1835 KiB

Open AccessEditor’s ChoiceArticle

Flood Control Versus Water Conservation in Reservoirs: A New Policy to Allocate Available Storage

by Ivan Gabriel-Martin, Alvaro Sordo-Ward, David Santillán and Luis Garrote

Water 2020, 12(4), 994; https://doi.org/10.3390/w12040994 - 1 Apr 2020

Cited by 6 | Viewed by 5384

Abstract

The aim of this study is to contribute to solving conflicts that arise in the operation of multipurpose reservoirs when determining maximum conservation levels (MCLs). The specification of MCLs in reservoirs that are operated for water supply and flood control may imply a [...] Read more.

The aim of this study is to contribute to solving conflicts that arise in the operation of multipurpose reservoirs when determining maximum conservation levels (MCLs). The specification of MCLs in reservoirs that are operated for water supply and flood control may imply a reduction in the volume of water supplied with a pre-defined reliability in the system. The procedure presented in this study consists of the joint optimization of the reservoir yield with a specific reliability subject to constraints imposed by hydrological dam safety and downstream river safety. We analyzed two different scenarios by considering constant or variable initial reservoir level prior to extreme flood events. In order to achieve the global optimum configuration of MCLs for each season, we propose the joint optimization of three variables: minimize the maximum reservoir level (return period of 1000 years), minimize the maximum released outflow (return period of 500 years) and maximize the reservoir yield with 90% reliability. We applied the methodology to Riaño Dam, jointly operated for irrigation and flood control. Improvements in the maximum reservoir yield (with 90% reliability) increased up to 10.1% with respect to the currently supplied annual demand (545 hm³) for the same level of dam and downstream hydrological safety. The improvement could increase up to 26.8% when compared to deterministic procedures. Moreover, dam stakeholders can select from a set of Pareto-optimal configurations depending on if their main emphasis is to maintain/increase the hydrological safety, or rather to maintain/increase the reservoir yield. Full article

(This article belongs to the Special Issue Water Resources Management Models for Policy Assessment)

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26 pages, 25663 KiB

Open AccessEditor’s ChoiceArticle

Symmetrical Rank-Three Vectorized Loading Scores Quasi-Newton for Identification of Hydrogeological Parameters and Spatiotemporal Recharges

by Chien-Lin Huang, Nien-Sheng Hsu, Fu-Jian Hsu, Gene J.-Y. You and Chun-Hao Yao

Water 2020, 12(4), 995; https://doi.org/10.3390/w12040995 - 1 Apr 2020

Viewed by 2519

Abstract

In a multi-layered groundwater model, achieving accurate spatiotemporal identification and solving the ill-posed problem is the vital topic for model calibration. This study proposes a symmetry rank three vectorized loading scores (SR3 VLS) quasi-Newton algorithm by modifying the Levenberg–Marquardt algorithm and importing a [...] Read more.

In a multi-layered groundwater model, achieving accurate spatiotemporal identification and solving the ill-posed problem is the vital topic for model calibration. This study proposes a symmetry rank three vectorized loading scores (SR3 VLS) quasi-Newton algorithm by modifying the Levenberg–Marquardt algorithm and importing a rank three structure from Broyden–Fletcher–Goldfarb–Shanno algorithm for identification of hydrogeological parameters and spatiotemporal recharge simultaneously. To accelerate directional convergence and approach a global optimum, this study uses a vectorized limited switchable step size in the transmissive groundwater inverse problem. The Hessian approximation rank three uses high and low-rank factor loading scores analyzed from simulated storage fluctuation between adjacent iterations for calculation and matrix correction. Two numerical experiments were designed to validate the proposing algorithm, showing the SR3 VLS quasi-Newton reduced the error percentages of the identified parameters by 1.63% and 9.65% compared to the Jacobian quasi-Newton. The proposing method is applied to the Chou-Shui River alluvial fan groundwater system in Taiwan. Results show that the simulated storage error decreased rapidly in six iterations, and has good head convergence as small as 0.11% with a root-mean-square-error (RMSE) of 0.134 m, indicating that the proposing algorithm reduces the computational cost to converge to the true solution. Full article

(This article belongs to the Special Issue Computational Methods in Water Resources)

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23 pages, 4109 KiB

Open AccessEditor’s ChoiceArticle

Statistical Evaluation of the Latest GPM-Era IMERG and GSMaP Satellite Precipitation Products in the Yellow River Source Region

by Jiayong Shi, Fei Yuan, Chunxiang Shi, Chongxu Zhao, Limin Zhang, Liliang Ren, Yonghua Zhu, Shanhu Jiang and Yi Liu

Water 2020, 12(4), 1006; https://doi.org/10.3390/w12041006 - 1 Apr 2020

Cited by 40 | Viewed by 4616

Abstract

As the successor of Tropical Rainfall Measuring Mission, Global Precipitation Measurement (GPM) has released a range of satellite-based precipitation products (SPPs). This study conducts a comparative analysis on the quality of the integrated multisatellite retrievals for GPM (IMERG) and global satellite mapping of [...] Read more.

As the successor of Tropical Rainfall Measuring Mission, Global Precipitation Measurement (GPM) has released a range of satellite-based precipitation products (SPPs). This study conducts a comparative analysis on the quality of the integrated multisatellite retrievals for GPM (IMERG) and global satellite mapping of precipitation (GSMaP) SPPs in the Yellow River source region (YRSR). This research includes the eight latest GPM-era SPPs, namely, IMERG “Early,” “Late,” and “Final” run SPPs (IMERG-E, IMERG-L, and IMERG-F) and GSMaP gauge-adjusted product (GSMaP-Gauge), microwave-infrared reanalyzed product (GSMaP-MVK), near-real-time product (GSMaP-NRT), near-real-time product with gauge-based adjustment (GSMaP-Gauge-NRT), and real-time product (GSMaP-NOW). In addition, the IMERG SPPs were compared with GSMaP SPPs at multiple spatiotemporal scales. Results indicate that among the three IMERG SPPs, IMERG-F exhibited the lowest systematic errors and the best quality, followed by IMERG-E and IMERG-L. IMERG-E and IMERG-L underestimated the occurrences of light-rain events but overestimated the moderate and heavy rain events. For GSMaP SPPs, GSMaP-Gauge presented the best performance in terms of various statistical metrics, followed by GSMaP-Gauge-NRT. GSMaP-MVK and GSMaP-NRT remarkably overestimated total precipitation, and GSMaP-NOW showed an evident underestimation. By comparing the performances of IMERG and GSMaP SPPs, GSMaP-Gauge-NRT provided the best precipitation estimates among all real-time and near-real-time SPPs. For post-real-time SPPs, GSMaP-Gauge presented the highest capability at the daily scale, and IMERG-F slightly outperformed the other SPPs at the monthly scale. This study is one of the earliest studies focusing on the quality of the latest IMERG and GSMaP SPPs. The findings of this study provide SPP developers with valuable information on the quality of the latest GPM-era SPPs in YRSR and help SPP researchers to refine the precipitation retrieving algorithms to improve the applicability of SPPs. Full article

(This article belongs to the Special Issue Applications of Remote Sensing and GIS in Hydrology II)

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29 pages, 4186 KiB

Open AccessEditor’s ChoiceReview

Water Network Partitioning into District Metered Areas: A State-Of-The-Art Review

by Xuan Khoa Bui, Malvin S. Marlim and Doosun Kang

Water 2020, 12(4), 1002; https://doi.org/10.3390/w12041002 - 1 Apr 2020

Cited by 59 | Viewed by 13282

Abstract

A water distribution network (WDN) is an indispensable element of civil infrastructure that provides fresh water for domestic use, industrial development, and fire-fighting. However, in a large and complex network, operation and management (O&M) can be challenging. As a technical initiative to improve [...] Read more.

A water distribution network (WDN) is an indispensable element of civil infrastructure that provides fresh water for domestic use, industrial development, and fire-fighting. However, in a large and complex network, operation and management (O&M) can be challenging. As a technical initiative to improve O&M efficiency, the paradigm of “divide and conquer” can divide an original WDN into multiple subnetworks. Each subnetwork is controlled by boundary pipes installed with gate valves or flow meters that control the water volume entering and leaving what are known as district metered areas (DMAs). Many approaches to creating DMAs are formulated as two-phase procedures, clustering and sectorizing, and are called water network partitioning (WNP) in general. To assess the benefits and drawbacks of DMAs in a WDN, we provide a comprehensive review of various state-of-the-art approaches, which can be broadly classified as: (1) Clustering algorithms, which focus on defining the optimal configuration of DMAs; and (2) sectorization procedures, which physically decompose the network by selecting pipes for installing flow meters or gate valves. We also provide an overview of emerging problems that need to be studied. Full article

(This article belongs to the Special Issue Smart Urban Water Networks)

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18 pages, 4437 KiB

Open AccessEditor’s ChoiceArticle

The Selection of Rain Gauges and Rainfall Parameters in Estimating Intensity-Duration Thresholds for Landslide Occurrence: Case Study from Wayanad (India)

by Minu Treesa Abraham, Neelima Satyam, Ascanio Rosi, Biswajeet Pradhan and Samuele Segoni

Water 2020, 12(4), 1000; https://doi.org/10.3390/w12041000 - 1 Apr 2020

Cited by 40 | Viewed by 8181

Abstract

Recurring landslides in the Western Ghats have become an important concern for authorities, considering the recent disasters that occurred during the 2018 and 2019 monsoons. Wayanad is one of the highly affected districts in Kerala State (India), where landslides have become a threat [...] Read more.

Recurring landslides in the Western Ghats have become an important concern for authorities, considering the recent disasters that occurred during the 2018 and 2019 monsoons. Wayanad is one of the highly affected districts in Kerala State (India), where landslides have become a threat to lives and properties. Rainfall is the major factor which triggers landslides in this region, and hence, an early warning system could be developed based on empirical rainfall thresholds considering the relationship between rainfall events and their potential to initiate landslides. As an initial step in achieving this goal, a detailed study was conducted to develop a regional scale rainfall threshold for the area using intensity and duration conditions, using the landslides that occurred during the years from 2010 to 2018. Detailed analyses were conducted in order to select the most effective method for choosing a reference rain gauge and rainfall event associated with the occurrence of landslides. The study ponders the effect of the selection of rainfall parameters for this data-sparse region by considering four different approaches. First, a regional scale threshold was defined using the nearest rain gauge. The second approach was achieved by selecting the most extreme rainfall event recorded in the area, irrespective of the location of landslide and rain gauge. Third, the classical definition of intensity was modified from average intensity to peak daily intensity measured by the nearest rain gauge. In the last approach, four different local scale thresholds were defined, exploring the possibility of developing a threshold for a uniform meteo-hydro-geological condition instead of merging the data and developing a regional scale threshold. All developed thresholds were then validated and empirically compared to find the best suited approach for the study area. From the analysis, it was observed that the approach selecting the rain gauge based on the most extreme rainfall parameters performed better than the other approaches. The results are useful in understanding the sensitivity of Intensity–Duration threshold models to some boundary conditions such as rain gauge selection, the intensity definition and the strategy of subdividing the area into independent alert zones. The results were discussed with perspective on a future application in a regional scale Landslide Early Warning System (LEWS) and on further improvements needed for this objective. Full article

(This article belongs to the Special Issue Rainfall Thresholds and Other Approaches for Landslide Prediction and Early Warning)

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23 pages, 9344 KiB

Open AccessEditor’s ChoiceArticle

Extreme Floods in Small Mediterranean Catchments: Long-Term Response to Climate Variability and Change

by Gerardo Benito, Yolanda Sanchez-Moya, Alicia Medialdea, Mariano Barriendos, Mikel Calle, Mayte Rico, Alfonso Sopeña and Maria J. Machado

Water 2020, 12(4), 1008; https://doi.org/10.3390/w12041008 - 1 Apr 2020

Cited by 18 | Viewed by 5203

Abstract

Climate change implies changes in the frequency and magnitude of flood events. The influence of climate variability on flooding was evaluated by an analysis of sedimentary (palaeofloods) and documentary archives. A 500-year palaeoflood record at Montlleó River (657 km² in catchment area), [...] Read more.

Climate change implies changes in the frequency and magnitude of flood events. The influence of climate variability on flooding was evaluated by an analysis of sedimentary (palaeofloods) and documentary archives. A 500-year palaeoflood record at Montlleó River (657 km² in catchment area), eastern Spain, revealed up to 31 palaeofloods with a range of discharges of 20–950 m³ s⁻¹, and with at least five floods exceeding 740–950 m³ s⁻¹. This information contrasts with the available gauged flood registers (since year 1971) with an annual maximum daily discharge of 129 m³ s⁻¹. Our palaeoflood dataset indicates flood cluster episodes at (1) 1570–1620, (2) 1775–1795, (3) 1850–1890, and (4) 1920–1969. Flood rich periods 1 and 3 corresponded to cooler than usual (about 0.3 °C and 0.2 °C) climate oscillations, whereas 2 and 4 were characterised by higher inter-annual climatic variability (floods and droughts). This high inter-annual rainfall variability increased over the last 150 years, leading to a reduction of annual maximum flow. Flood quantiles (>50 years) calculated from palaeoflood+gauged data showed 30%–40% higher peak discharges than those using only instrumental records, whereas when increasing the catchment area (1500 km²) the discharge estimation variance decreased to ~15%. The results reflect the higher sensitivity of small catchments to changes on flood magnitude and frequency due to climate variability whereas a larger catchment buffers the response due to the limited extent of convective storms. Our findings show that extended flood records provide robust knowledge about hazardous flooding that can assist in the prioritization of low-regret actions for flood-risk adaptation to climate change. Full article

(This article belongs to the Special Issue Influence of Climate Change on Floods)

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15 pages, 5261 KiB

Open AccessEditor’s ChoiceArticle

Differences of Regulative Flexibility between Hydrological Isolated and Connected Lakes in a Large Floodplain: Insight from Inundation Dynamics and Landscape Heterogeneity

by Jiakun Teng, Shaoxia Xia, Yu Liu, Peng Cui, Jiang Chen, Wuwei Si, Houlang Duan and Xiubo Yu

Water 2020, 12(4), 991; https://doi.org/10.3390/w12040991 - 1 Apr 2020

Cited by 11 | Viewed by 2803

Abstract

The inundation areas of floodplains are crucial to wetland ecosystems, especially in supporting biodiversity. Accurately identifying the spatial and temporal patterns of inundation areas is important for understanding floodplain ecosystem processes. Here, lakes in the Yangtze River Floodplain were divided into two types [...] Read more.

The inundation areas of floodplains are crucial to wetland ecosystems, especially in supporting biodiversity. Accurately identifying the spatial and temporal patterns of inundation areas is important for understanding floodplain ecosystem processes. Here, lakes in the Yangtze River Floodplain were divided into two types according to hydrological conditions: the natural connected lakes (Dongting Lake and Poyang Lake) with natural water level fluctuations and the isolated lakes (lakes in Jianghan Plain) with stable water levels. We established a method to identify inundation areas using multi-sources remote sensing data based on the Google Earth Engine. The dynamics of inundation areas were determined, and the relative indices were calculated in common year (2017) and a drought year (2018). The differences between the connected lakes and the isolated lakes were analyzed, and impacts of hydrological fluctuations on inundation area and habitat quality were evaluated. The results show that lakes with natural hydrological fluctuations have a greater regulative flexibility, with both patch density (PD) and submerged elasticity index (SEI) values higher than that of isolated lakes. The trend of the vegetation index in the connected lakes and in the isolated lakes is also different. The mean EVI in Dongting Lake and Poyang Lake showed a U-shaped trend which is similar to the shape of the trend of PD. The trend of mean enhanced vegetation index (EVI) in the isolated lakes is the opposite and has a lower range of variation over a year. This study provides new indicators and rapid methods for habitat quality assessment in floodplains, as well as presenting scientific information useful for improving wetland management in the middle and lower Yangtze River. Full article

(This article belongs to the Section Water Resources Management, Policy and Governance)

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25 pages, 6705 KiB

Open AccessEditor’s ChoiceArticle

Mapping of Groundwater Spring Potential in Karst Aquifer System Using Novel Ensemble Bivariate and Multivariate Models

by Viet-Ha Nhu, Omid Rahmati, Fatemeh Falah, Saeed Shojaei, Nadhir Al-Ansari, Himan Shahabi, Ataollah Shirzadi, Krzysztof Górski, Hoang Nguyen and Baharin Bin Ahmad

Water 2020, 12(4), 985; https://doi.org/10.3390/w12040985 - 31 Mar 2020

Cited by 57 | Viewed by 6034

Abstract

Groundwater is an important natural resource in arid and semi-arid environments, where discharge from karst springs is utilized as the principal water supply for human use. The occurrence of karst springs over large areas is often poorly documented, and interpolation strategies are often [...] Read more.

Groundwater is an important natural resource in arid and semi-arid environments, where discharge from karst springs is utilized as the principal water supply for human use. The occurrence of karst springs over large areas is often poorly documented, and interpolation strategies are often utilized to map the distribution and discharge potential of springs. This study develops a novel method to delineate karst spring zones on the basis of various hydrogeological factors. A case study of the Bojnourd Region, Iran, where spring discharge measurements are available for 359 sites, is used to demonstrate application of the new approach. Spatial mapping is achieved using ensemble modelling, which is based on certainty factors (CF) and logistic regression (LR). Maps of the CF and LR components of groundwater potential were generated individually, and then, combined to prepare an ensemble map of the study area. The accuracy (A) of the ensemble map was then assessed using area under the receiver operating characteristic curve. Results of this analysis show that LR (A = 78%) outperformed CF (A = 67%) in terms of the comparison between model predictions and known occurrences of karst springs (i.e., calibration data). However, combining the CF and LR results through ensemble modelling produced superior accuracy (A = 85%) in terms of spring potential mapping. By combining CF and LR statistical models through ensemble modelling, weaknesses in CF and LR methods are offset, and therefore, we recommend this ensemble approach for similar karst mapping projects. The methodology developed here offers an efficient method for assessing spring discharge and karst spring potentials over regional scales. Full article

(This article belongs to the Special Issue Groundwater Modelling in Karst Areas)

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17 pages, 5571 KiB

Open AccessEditor’s ChoiceArticle

Performance Investigation of the Immersed Depth Effects on a Water Wheel Using Experimental and Numerical Analyses

by Mengshang Zhao, Yuan Zheng, Chunxia Yang, Yuquan Zhang and Qinghong Tang

Water 2020, 12(4), 982; https://doi.org/10.3390/w12040982 - 30 Mar 2020

Cited by 8 | Viewed by 7987

Abstract

The purpose of this research is to study the effect of different immersed depths on water wheel performance and flow characteristics using numerical simulations. The results indicate that the simulation methods are consistent with experiments with a maximum error less than 5%. Under [...] Read more.

The purpose of this research is to study the effect of different immersed depths on water wheel performance and flow characteristics using numerical simulations. The results indicate that the simulation methods are consistent with experiments with a maximum error less than 5%. Under the same rotational speeds, the efficiency is much higher and the fluctuation amplitude of the torque is much smaller as the immersed radius ratio increases, and until an immersed radius ratio of 82.76%, the wheel shows the best performance, achieving a maximum efficiency of 18.05% at a tip-speed ratio (TSR) of 0.1984. The average difference in water level increases as the immersed radius ratio increases until 82.76%. The water area is much wider and the water volume fraction shows more intense change at the inlet stage at a deep immersed depth. At an immersed radius ratio of 82.76%, some air intrudes into the water at the inlet stage, coupled with a dramatic change in the water volume fraction that would make the flow more complex. Furthermore, eddies are found to gradually generate in a single flow channel nearly at the same time, except for an immersed depth of 1.2 m. However, eddies generate in two flow channels and can develop initial vortexes earlier than other cases because of the elevation of the upstream water level at an immersed radius ratio of 82.76%. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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22 pages, 2279 KiB

Open AccessEditor’s ChoiceArticle

Evaluation of Dam Break Social Impact Assessments Based on an Improved Variable Fuzzy Set Model

by Guanjie He, Junrui Chai, Yuan Qin, Zengguang Xu and Shouyi Li

Water 2020, 12(4), 970; https://doi.org/10.3390/w12040970 - 29 Mar 2020

Cited by 10 | Viewed by 3771

Abstract

In recent years attention has shifted from “dam safety” to “dam risk” due to the high loss characteristics of dam breaks. Despite this, there has been little research on social impact assessments. Variable fuzzy sets (VFSs) are a theoretical system for dealing with [...] Read more.

In recent years attention has shifted from “dam safety” to “dam risk” due to the high loss characteristics of dam breaks. Despite this, there has been little research on social impact assessments. Variable fuzzy sets (VFSs) are a theoretical system for dealing with uncertainty that are used in many industries. However, the relative membership degree (RMD) calculations required for VFSs are complicated and data can be overlooked. Furthermore, the RMD is highly subjective when dealing with qualitative problems, which can seriously affect the accuracy of the results. This study introduces grey system theory (GST) which analyzes the RMD characteristics to improve traditional VFSs. A new method for calculating the social impact of a dam break is proposed based on the correlation between the core parameters of the two theories. The Liujiatai Reservoir is used as a test case and the new and traditional evaluation methods are compared. The results show that the proposed method has advantages when dealing with uncertainty that are consistent with the characteristics of the problems associated with dam break social impact assessments. Moreover, the evaluation results obtained using the proposed method are consistent with, or more accurate than, those obtained using the traditional method. Full article

(This article belongs to the Section Water Resources Management, Policy and Governance)

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58 pages, 1781 KiB

Open AccessEditor’s ChoiceReview

Worldwide Regulations and Guidelines for Agricultural Water Reuse: A Critical Review

by Farshid Shoushtarian and Masoud Negahban-Azar

Water 2020, 12(4), 971; https://doi.org/10.3390/w12040971 - 29 Mar 2020

Cited by 132 | Viewed by 19337

Abstract

Water reuse is gaining momentum as a beneficial practice to address the water crisis, especially in the agricultural sector as the largest water consumer worldwide. With recent advancements in wastewater treatment technologies, it is possible to produce almost any water quality. However, the [...] Read more.

Water reuse is gaining momentum as a beneficial practice to address the water crisis, especially in the agricultural sector as the largest water consumer worldwide. With recent advancements in wastewater treatment technologies, it is possible to produce almost any water quality. However, the main human and environmental concerns are still to determine what constituents must be removed and to what extent. The main objectives of this study were to compile, evaluate, and compare the current agricultural water reuse regulations and guidelines worldwide, and identify the gaps. In total, 70 regulations and guidelines, including Environmental Protection Agency (EPA), International Organization for Standardization (ISO), Food and Agriculture Organization of the United Nations (FAO), World Health Organization (WHO), the United States (state by state), European Commission, Canada (all provinces), Australia, Mexico, Iran, Egypt, Tunisia, Jordan, Palestine, Oman, China, Kuwait, Israel, Saudi Arabia, France, Cyprus, Spain, Greece, Portugal, and Italy were investigated in this study. These regulations and guidelines were examined to compile a comprehensive database, including all of the water quality monitoring parameters, and necessary treatment processes. In summary, results showed that the regulations and guidelines are mainly human-health centered, insufficient regarding some of the potentially dangerous pollutants such as emerging constituents, and with large discrepancies when compared with each other. In addition, some of the important water quality parameters such as some of the pathogens, heavy metals, and salinity are only included in a small group of regulations and guidelines investigated in this study. Finally, specific treatment processes have been only mentioned in some of the regulations and guidelines, and with high levels of discrepancy. Full article

(This article belongs to the Section Wastewater Treatment and Reuse)

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19 pages, 2562 KiB

Open AccessEditor’s ChoiceArticle

Hydropower Generation Through Pump as Turbine: Experimental Study and Potential Application to Small-Scale WDN

by Matteo Postacchini, Giovanna Darvini, Fiorenza Finizio, Leonardo Pelagalli, Luciano Soldini and Elisa Di Giuseppe

Water 2020, 12(4), 958; https://doi.org/10.3390/w12040958 - 28 Mar 2020

Cited by 27 | Viewed by 16374

Abstract

Pump-As-Turbine (PAT) technology is a smart solution to produce energy in a sustainable way at small scale, e.g., through its exploitation in classical Water Distribution Networks (WDNs). PAT application may actually represent a suitable solution to obtain both pressure regulation and electrical energy [...] Read more.

Pump-As-Turbine (PAT) technology is a smart solution to produce energy in a sustainable way at small scale, e.g., through its exploitation in classical Water Distribution Networks (WDNs). PAT application may actually represent a suitable solution to obtain both pressure regulation and electrical energy production. This technology enables one to significantly reduce both design and maintenance costs if compared to traditional turbine applications. In this work, the potential hydropower generation was evaluated through laboratory tests focused on the characterization of a pump working in reverse mode, i.e., as a PAT. Both hydrodynamic (pressure and discharge) and mechanical (rotational speed and torque) conditions were varied during the tests, with the aim to identify the most efficient PAT configurations and provide useful hints for possible real-world applications. The experimental findings confirm the good performances of the PAT system, especially when rotational speed and water demand are, respectively, larger than 850 rpm and 8 L/s, thus leading to efficiencies greater than 50%. Such findings were applied to a small municipality, where daily distribution of pressure and discharge were recorded upstream of the local WDN, where a Pressure Reducing Valve (PRV) is installed. Under the hypothesis of PRV replacement with the tested PAT, three different scenarios were studied, based on the mean recorded water demand and each characterized by specific values of PAT rotational speed. The best performances were observed for the largest tested speeds (1050 and 1250 rpm), which lead to pressure drops smaller than those actually due to the PRV, thus guaranteeing the minimum pressure for users, but also to mechanical powers smaller than 100 W. When a larger mean water demand is assumed, much better performances are reached, especially for large speeds (1250 rpm) that lead to mechanical powers larger than 1 kW combined to head drops a bit larger than those observed using the PRV. A suitable design is thus fundamental for the real-world PAT application. Full article

(This article belongs to the Special Issue Application of Innovative Technologies for Active Control and Energy Efficiency in Water Supply Systems)

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22 pages, 6845 KiB

Open AccessEditor’s ChoiceArticle

Hydrochemical Characteristics and Water Quality Evaluation of Rivers in Different Regions of Cities: A Case Study of Suzhou City in Northern Anhui Province, China

by Yaqi Jiang, Herong Gui, Hao Yu, Meichen Wang, Hongxia Fang, Chunlei Wang, Chen Chen, Yaru Zhang and Yiheng Huang

Water 2020, 12(4), 950; https://doi.org/10.3390/w12040950 - 27 Mar 2020

Cited by 38 | Viewed by 4535

Abstract

To study the disparity of river hydrochemical characteristics and water quality in different regions of the city, this paper took the Tuo River in the center of Suzhou, Northern Anhui, China and the Bian River on the edge of the urban area as [...] Read more.

To study the disparity of river hydrochemical characteristics and water quality in different regions of the city, this paper took the Tuo River in the center of Suzhou, Northern Anhui, China and the Bian River on the edge of the urban area as the research objects, used Piper trigram, Gibbs diagram, and hydrogen and oxygen isotope content characteristics to analyze the geochemical characteristics of surface water in the study area, and then the improved fuzzy comprehensive evaluation method was used to evaluate the water quality. The results showed that the hydrochemical types of the two rivers were SO₄-Cl-Na type, and the contents of Na⁺, K⁺, SO₄²⁻, Cl⁻, Ca²⁺, total phosphorus (TP) in the Bian River at the edge of the city were much higher than those in the Tuo River at the center of the city (ANOVA, p < 0.001). Gibbs diagram showed that the ion composition of the two rivers was mainly affected by rock weathering. The results of correlation analysis and water quality evaluation showed that Bian River was greatly affected by agricultural non-point source pollution, and its water quality was poor, class IV and class V water account for 95%, while, for Tuo River, due to the strong artificial protection, class II and class III accounted for 40.74% and 59.26%, respectively, and the overall water quality was better than that of Bian River. The evaluation results of irrigation water quality showed that the samples from Tuo River were high in salt and low in alkali, which could be used for irrigation when the soil leaching conditions were good, while Bian River water samples were high in salt and medium in alkali, which was suitable for irrigation of plants with strong salt tolerance. Full article

(This article belongs to the Section Water Use and Scarcity)

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26 pages, 4432 KiB

Open AccessEditor’s ChoiceArticle

High-Resolution Mapping of Japanese Microplastic and Macroplastic Emissions from the Land into the Sea

by Yasuo Nihei, Takushi Yoshida, Tomoya Kataoka and Riku Ogata

Water 2020, 12(4), 951; https://doi.org/10.3390/w12040951 - 27 Mar 2020

Cited by 48 | Viewed by 13780

Abstract

Plastic debris presents a serious hazard to marine ecosystems worldwide. In this study, we developed a method to evaluate high-resolution maps of plastic emissions from the land into the sea offshore of Japan without using mismanaged plastic waste. Plastics were divided into microplastics [...] Read more.

Plastic debris presents a serious hazard to marine ecosystems worldwide. In this study, we developed a method to evaluate high-resolution maps of plastic emissions from the land into the sea offshore of Japan without using mismanaged plastic waste. Plastics were divided into microplastics (MicPs) and macroplastics (MacPs), and correlations between the observed MicP concentrations in rivers and basin characteristics, such as the urban area ratio and population density, were used to evaluate nationwide MicP concentration maps. A simple water balance analysis was used to calculate the annual outflow for each 1 km mesh to obtain the final MicP emissions, and the MacP input was evaluated based on the MicP emissions and the ratio of MacP/MicP obtained according to previous studies. Concentration data revealed that the MicP concentrations and basin characteristics were significantly and positively correlated. Water balance analyses demonstrated that our methods performed well for evaluating the annual flow rate, while reducing the computational load. The total plastic input (MicP + MacP) was widely distributed from 210–4776 t/yr and a map showed that plastic emissions were high for densely populated and highly urbanized areas in the Tokyo metropolitan area, as well as other large urban areas, especially Nagoya and Osaka. These results provide important insights that may be used to develop countermeasures against plastic pollution and the methods employed herein can also be used to evaluate plastic emissions in other regions. Full article

(This article belongs to the Section Water Quality and Contamination)

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19 pages, 6896 KiB

Open AccessEditor’s ChoiceArticle

A Three-Dimensional Numerical Study of Wave Induced Currents in the Cetraro Harbour Coastal Area (Italy)

by Giovanni Cannata, Federica Palleschi, Benedetta Iele and Francesco Cioffi

Water 2020, 12(4), 935; https://doi.org/10.3390/w12040935 - 26 Mar 2020

Cited by 4 | Viewed by 2763

Abstract

In this paper we propose a three-dimensional numerical study of the coastal currents produced by the wave motion in the area opposite the Cetraro harbour (Italy), during the most significant wave event for the coastal sediment transport. The aim of the present study [...] Read more.

In this paper we propose a three-dimensional numerical study of the coastal currents produced by the wave motion in the area opposite the Cetraro harbour (Italy), during the most significant wave event for the coastal sediment transport. The aim of the present study is the characterization of the current patterns responsible for the siltation that affects the harbour entrance area and the assessment of a project solution designed to limit this phenomenon. The numerical simulations are carried out by a three-dimensional non-hydrostatic model that is based on the Navier–Stokes equations expressed in integral and contravariant form on a time-dependent curvilinear coordinate system, in which the vertical coordinate moves in order to follow the free surface variations. The numerical simulations are carried out in two different geometric configurations: a present configuration, that reproduces the geometry of the coastal defence structures currently present in the harbour area and a project configuration, which reproduces the presence of a breakwater designed to modify the coastal currents in the area opposite the harbour entrance. Full article

(This article belongs to the Special Issue Numerical Modelling of Wave Fields and Currents in Coastal Area)

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18 pages, 5124 KiB

Open AccessEditor’s ChoiceArticle

Study on the Single-Multi-Objective Optimal Dispatch in the Middle and Lower Reaches of Yellow River for River Ecological Health

by Tao Bai, Xia Liu, Yan-ping HA, Jian-xia Chang, Lian-zhou Wu, Jian Wei and Jin Liu

Water 2020, 12(3), 915; https://doi.org/10.3390/w12030915 - 24 Mar 2020

Cited by 10 | Viewed by 3524

Abstract

Given the increasingly worsening ecology issues in the lower Yellow River, the Xiaolangdi reservoir is chosen as the regulation and control target, and the single and multi-objective operation by ecology and power generation in the lower Yellow River is studied in this paper. [...] Read more.

Given the increasingly worsening ecology issues in the lower Yellow River, the Xiaolangdi reservoir is chosen as the regulation and control target, and the single and multi-objective operation by ecology and power generation in the lower Yellow River is studied in this paper. This paper first proposes the following three indicators: the ecological elasticity coefficient (f1), the power generation elasticity coefficient (f2), and the ecological power generation profit and loss ratio (k). This paper then conducts a multi-target single dispatching study on ecology and power generation in the lower Yellow River. A genetic algorithm (GA) and an improved non-dominated genetic algorithm (NSGA-II) combining constraint processing and feasible space search techniques were used to solve the single-objective model with the largest power generation and the multi-objective optimal scheduling model considering both ecology and power generation. The calculation results show that: (1) the effectiveness of the NSGA-Ⅱcombined with constraint processing and feasible spatial search technology in reservoir dispatching is verified by an example; (2) compared with the operation model of maximizing power generation, the power generation of the target model was reduced by 0.87%, the ecological guarantee rate was increased by 18.75%, and the degree of the impact of ecological targets on the operating results was quantified; (3) in each typical year, the solution spatial distribution and dimensions of the single-target and multi-target models of change are represented by the Pareto-front curve, and a multi-objective operation plan is generated for decision makers to choose; (4) the f1, f2, and k indicators are selected to analyze the sensitivity of the five multi-objective plans and to quantify the interaction between ecological targets and power generation targets. Ultimately, this paper discusses the conversion relationship and finally recommends the best equilibrium solution in the multi-objective global equilibrium solution set. The results provide a decision-making basis for the multi-objective dispatching of the Xiaolangdi reservoir and have important practical significance for further improving the ecological health of the lower Yellow River. Full article

(This article belongs to the Special Issue Advances in Hydrologic Forecasts and Water Resources Management )

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24 pages, 7285 KiB

Open AccessEditor’s ChoiceArticle

Automatic Extraction of Supraglacial Lakes in Southwest Greenland during the 2014–2018 Melt Seasons Based on Convolutional Neural Network

by Jiawei Yuan, Zhaohui Chi, Xiao Cheng, Tao Zhang, Tian Li and Zhuoqi Chen

Water 2020, 12(3), 891; https://doi.org/10.3390/w12030891 - 22 Mar 2020

Cited by 15 | Viewed by 4592

Abstract

The mass loss of the Greenland Ice Sheet (GrIS) has implications for global sea level rise, and surface meltwater is an important factor that affects the mass balance. Supraglacial lakes (SGLs), which are representative and identifiable hydrologic features of surface meltwater on GrIS, [...] Read more.

The mass loss of the Greenland Ice Sheet (GrIS) has implications for global sea level rise, and surface meltwater is an important factor that affects the mass balance. Supraglacial lakes (SGLs), which are representative and identifiable hydrologic features of surface meltwater on GrIS, are a means of assessing surface ablation temporally and spatially. In this study, we have developed a robust method to automatically extract SGLs by testing the widely distributed SGLs area—in southwest Greenland (68°00′ N–70°00′ N, 48°00′ W–51°30′ W), and documented their dynamics from 2014 to 2018 using Landsat 8 OLI images. This method identifies water using Convolutional Neural Networks (CNN) and then extracts SGLs with morphological and geometrical algorithms. CNN combines spectral and spatial features and shows better water identification results than the widely used adaptive thresholding method (Otsu), and two machine learning methods (Random Forests (RF) and Support Vector Machine (SVM)). Our results show that the total SGLs area varied between 158 and 393 km² during 2014 to 2018; the area increased from 2014 to 2015, then decreased and reached the lowest point (158.73 km²) in 2018, when the most limited surface melting was observed. SGLs were most active during the melt season in 2015 with a quantity of 700 and a total area of 393.36 km². The largest individual lake developed in 2016, with an area of 9.30 km². As for the elevation, SGLs were most active in the area, with the elevation ranging from 1000 to 1500 m above sea level, and SGLs in 2016 were distributed at higher elevations than in other years. Our work proposes a method to extract SGLs accurately and efficiently. More importantly, this study is expected to provide data support to other studies monitoring the surface hydrological system and mass balance of the GrIS. Full article

(This article belongs to the Special Issue Applications of Remote Sensing and GIS in Hydrology II)

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26 pages, 4514 KiB

Open AccessEditor’s ChoiceArticle

Sustainable Water Resources Management in an Arid Area Using a Coupled Optimization-Simulation Modeling

by Siamak Farrokhzadeh, Seyed Arman Hashemi Monfared, Gholamreza Azizyan, Ali Sardar Shahraki, Maurits W. Ertsen and Edo Abraham

Water 2020, 12(3), 885; https://doi.org/10.3390/w12030885 - 21 Mar 2020

Cited by 27 | Viewed by 5641

Abstract

Severe water scarcity in recent years has magnified the economic, social, and environmental significance of water stress globally, making optimal planning in water resources necessary for sustainable socio-economic development. One of the regions that is most affected by this is the Sistan region [...] Read more.

Severe water scarcity in recent years has magnified the economic, social, and environmental significance of water stress globally, making optimal planning in water resources necessary for sustainable socio-economic development. One of the regions that is most affected by this is the Sistan region and its Hamoun wetland, located in south-east Iran. Water policies are essential to sustain current basin ecosystem services, maintaining a balance between conflicting demands from agriculture and the protection of wetland ecosystems. In the present study, a multi-objective optimization model is linked with the Water Evaluation and Planning (WEAP) software to optimize water allocation decisions over multiple years. We formulate and parameterize a multi-objective optimization problem where the net economic benefit from agriculture and the supply of environmental requirements were maximized, to analyze the trade-off between different stakeholders. This problem is modeled and solved for the study area with detailed agricultural, socio-economic, and environmental data for 30 years and quantification of ecosystem services. By plotting Pareto sets, we investigate the trade-offs between the two conflicting objectives and evaluate a possible compromise. The results are analyzed by comparing purely economic versus multi-objective scenarios on the Pareto front. Finally, the disadvantages and advantages of these scenarios are also qualitatively described to help the decision process for water resources managers. Full article

(This article belongs to the Special Issue Integrated Assessment of the Water–Energy–Land Nexus)

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21 pages, 4364 KiB

Open AccessEditor’s ChoiceArticle

Estimating 500-m Resolution Soil Moisture Using Sentinel-1 and Optical Data Synergy

by Myriam Foucras, Mehrez Zribi, Clément Albergel, Nicolas Baghdadi, Jean-Christophe Calvet and Thierry Pellarin

Water 2020, 12(3), 866; https://doi.org/10.3390/w12030866 - 20 Mar 2020

Cited by 34 | Viewed by 6873

Abstract

The aim of this study is to estimate surface soil moisture at a spatial resolution of 500 m and a temporal resolution of at least 6 days, by combining remote sensing data from Sentinel-1 and optical data from Sentinel-2 and MODIS (Moderate-Resolution Imaging [...] Read more.

The aim of this study is to estimate surface soil moisture at a spatial resolution of 500 m and a temporal resolution of at least 6 days, by combining remote sensing data from Sentinel-1 and optical data from Sentinel-2 and MODIS (Moderate-Resolution Imaging Spectroradiometer). The proposed methodology is based on the change detection technique, applied to a series of measurements over a three-year period (2015 to 2018). The algorithm described here as “Soil Moisture Estimations from the Synergy of Sentinel-1 and optical sensors (SMES)” proposes different options, allowing information from vegetation densities and seasonal conditions to be taken into account. The output from this algorithm is a moisture index ranging between 0 and 1, with 0 corresponding to the driest soils and 1 to the wettest soils. This methodology has been tested at different test sites (South of France, Central Tunisia, Western Benin and Southwestern Niger), characterized by a wide range of different climatic conditions. The resulting surface soil moisture estimations are compared with in situ measurements and already existing satellite-derived soil moisture ASCAT (Advanced SCATterometer) products. They are found to be well correlated, for the African regions in particular (RMSE below 6 vol.%). This outcome indicates that the proposed algorithm can be used with confidence to estimate the surface soil moisture of a wide range of climatically different sites. Full article

(This article belongs to the Special Issue Applications of Remote Sensing and GIS in Hydrology II)

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17 pages, 252 KiB

Open AccessEditor’s ChoiceArticle

Drought Victims Demand Justice: Politicization of Drought by Farmers in Southern Germany over Time

by Wibke Müller

Water 2020, 12(3), 871; https://doi.org/10.3390/w12030871 - 20 Mar 2020

Cited by 4 | Viewed by 3537

Abstract

Farmers have an important role in problematizing and politicizing drought. Following the argumentative turn in policy analysis, the paper analyzes the process of problem definition by means of a framing analysis, zooming in on four major drought events covered in German farming sector [...] Read more.

Farmers have an important role in problematizing and politicizing drought. Following the argumentative turn in policy analysis, the paper analyzes the process of problem definition by means of a framing analysis, zooming in on four major drought events covered in German farming sector journals that are published by farmers’ associations. The article compares the framing of the four most-cited drought events—1947, 1975–76, 2003, and 2011–12—in order to better understand how problematization has changed over time, and how farmers justify and rationalize calls for political action. Three research questions are answered: What problems are named by farmers journals when describing drought events, and what solutions are proposed? Who is considered responsible for problems and solutions? How has framing of drought changed over time? The paper shows that farmers frame drought as a matter of justice and assert their perceived right to subsidies, compensation, farmer-friendly tax policies, and market regulations by the state. From 2003, drought has been framed in association with climate change. The data findings suggest that there is no post-productivist, post-exceptionalist paradigm shift connected to proposed drought policy solutions. Drought framings appear to be persistent, giving priority to assured farmers’ incomes, not water distribution. Considering the lobby power of farmers’ associations in Germany, this finding helps to understand why state interventions remain the same over time. Full article

(This article belongs to the Special Issue Attention and Water Governance: An Agenda-Setting Perspective)

24 pages, 6850 KiB

Open AccessEditor’s ChoiceArticle

Classification of Management Alternatives to Combat Reservoir Sedimentation

by Gregory L. Morris

Water 2020, 12(3), 861; https://doi.org/10.3390/w12030861 - 19 Mar 2020

Cited by 71 | Viewed by 13845

Abstract

Sedimentation is steadily depleting reservoir capacity worldwide, threatening the reliability of water supplies, flood control, hydropower energy and other benefits that form the basis of today’s water-intensive society. The strategies available to combat reservoir sedimentation may be classed into four broad categories. Three [...] Read more.

Sedimentation is steadily depleting reservoir capacity worldwide, threatening the reliability of water supplies, flood control, hydropower energy and other benefits that form the basis of today’s water-intensive society. The strategies available to combat reservoir sedimentation may be classed into four broad categories. Three proactive categories seek to improve the sediment balance across reservoirs by: (a) reducing sediment yield from the watershed, (b) routing sediment-laden flows around or through the storage pool, and (c) removing deposited sediment following deposition. The fourth category (d) consists of strategies that adapt to capacity loss, without addressing the sediment balance. Successful management will typically combine multiple strategies. This paper presents a comprehensive classification of both proactive and adaptive strategies, consistent with current international practice. Functional descriptions and examples are given for each strategy, and criteria are provided to differentiate between them when there is potential for ambiguity. The classification categories can be used as a checklist of strategies to consider in evaluating sediment management alternatives for new designs as well as remedial work at existing sediment-challenged reservoirs. This will also help practitioners to more clearly describe and communicate the nature of their management activities. Widespread application of both active and adaptive strategies is required to bring sedimentation under control to sustain benefits of water storage for today’s and future generations. Full article

(This article belongs to the Special Issue Reservoir Sustainability: Engineering, Economics, and Ecosystems)

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31 pages, 5735 KiB

Open AccessEditor’s ChoiceReview

CFD Modeling of Effluent Discharges: A Review of Past Numerical Studies

by Abdolmajid Mohammadian, Hossein Kheirkhah Gildeh and Ioan Nistor

Water 2020, 12(3), 856; https://doi.org/10.3390/w12030856 - 18 Mar 2020

Cited by 23 | Viewed by 5068

Abstract

Effluent discharge mixing and dispersion have been studied for many decades. Studies began with experimental investigations of geometrical and concentration characteristics of the jets in the near-field zone. More robust experiments were performed using Laser-Induced Fluorescence (LIF) and Particle Image Velocimetry (PIV) systems [...] Read more.

Effluent discharge mixing and dispersion have been studied for many decades. Studies began with experimental investigations of geometrical and concentration characteristics of the jets in the near-field zone. More robust experiments were performed using Laser-Induced Fluorescence (LIF) and Particle Image Velocimetry (PIV) systems starting in the 20th century, which led to more accurate measurement and analysis of jet behavior. The advancement of computing systems over the past two decades has led to the development of various numerical methods, which have been implemented in Computational Fluid Dynamics (CFD) codes to predict fluid motion and characteristics. Numerical modeling of mixing and dispersion is increasingly preferred over laboratory experiments of effluent discharges in both academia and industry. More computational resources and efficient numerical schemes have helped increase the popularity of using CFD models in jet and plume modeling. Numerous models have been developed over time, each with different capabilities to facilitate the investigation of all aspects of effluent discharges. Among these, Reynolds-averaged Navier-Stokes (RANS) and Large Eddy Simulations (LES) are at present the most popular CFD models employing effluent discharge modeling. This paper reviews state-of-the-art numerical modeling studies for different types and configurations of discharges, including positively and negatively buoyant discharges, which have mostly been completed over the past two decades. The numerical results of these studies are summarized and critically discussed in this review. Various aspects related to the impact of turbulence models, such as k-ε and Launder-Reece-Rodi (LRR) models, are reviewed herein. RANS and LES models are reviewed, and implications for the simulation of jet and plume mixing are discussed to develop a reference for future researchers performing numerical investigations on jet mixing and dispersion. Full article

(This article belongs to the Section Water Resources Management, Policy and Governance)

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14 pages, 2647 KiB

Open AccessEditor’s ChoiceArticle

Nonlinear Autoregressive Neural Networks to Predict Hydraulic Fracturing Fluid Leakage into Shallow Groundwater

by Reza Taherdangkoo, Alexandru Tatomir, Mohammad Taherdangkoo, Pengxiang Qiu and Martin Sauter

Water 2020, 12(3), 841; https://doi.org/10.3390/w12030841 - 17 Mar 2020

Cited by 38 | Viewed by 4060

Abstract

Hydraulic fracturing of horizontal wells is an essential technology for the exploitation of unconventional resources, but led to environmental concerns. Fracturing fluid upward migration from deep gas reservoirs along abandoned wells may pose contamination threats to shallow groundwater. This study describes the novel [...] Read more.

Hydraulic fracturing of horizontal wells is an essential technology for the exploitation of unconventional resources, but led to environmental concerns. Fracturing fluid upward migration from deep gas reservoirs along abandoned wells may pose contamination threats to shallow groundwater. This study describes the novel application of a nonlinear autoregressive (NAR) neural network to estimate fracturing fluid flow rate to shallow aquifers in the presence of an abandoned well. The NAR network is trained using the Levenberg–Marquardt (LM) and Bayesian Regularization (BR) algorithms and the results were compared to identify the optimal network architecture. For NAR-LM model, the coefficient of determination (R²) between measured and predicted values is 0.923 and the mean squared error (MSE) is 4.2 × 10⁻⁴, and the values of R² = 0.944 and MSE = 2.4 × 10⁻⁴ were obtained for the NAR-BR model. The results indicate the robustness and compatibility of NAR-LM and NAR-BR models in predicting fracturing fluid flow rate to shallow aquifers. This study shows that NAR neural networks can be useful and hold considerable potential for assessing the groundwater impacts of unconventional gas development. Full article

(This article belongs to the Special Issue Contaminant Transport and Fate)

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27 pages, 4066 KiB

Open AccessEditor’s ChoiceArticle

Unsustainability Syndrome—From Meteorological to Agricultural Drought in Arid and Semi-Arid Regions

by Ali Torabi Haghighi, Nizar Abou Zaki, Pekka M. Rossi, Roohollah Noori, Ali Akbar Hekmatzadeh, Hossein Saremi and Bjørn Kløve

Water 2020, 12(3), 838; https://doi.org/10.3390/w12030838 - 16 Mar 2020

Cited by 50 | Viewed by 5222

Abstract

Water is the most important resource for sustainable agriculture in arid and semi-arid regions, where agriculture is the mainstay for rural societies. By relating the water usage to renewable water resources, we define three stages from sustainable to unsustainable water resources: (1) sustainable, [...] Read more.

Water is the most important resource for sustainable agriculture in arid and semi-arid regions, where agriculture is the mainstay for rural societies. By relating the water usage to renewable water resources, we define three stages from sustainable to unsustainable water resources: (1) sustainable, where water use is matched by renewable water capacity, ensuring sustainable water resources; (2) transitional, where water use occasionally exceeds renewable water capacity; and (3) unsustainable, with lack of water resources for agriculture, society, and the environment. Using available drought indicators (standardized precipitation index (SPI) and streamflow drought index (SDI)) and two new indices for agricultural drought (overall agricultural drought index (OADI) and agricultural drought index (ADI)), we evaluated these stages using the example of Fars province in southern Iran in the period 1977–2016. A hyper-arid climate prevailed for an average of 32% of the province’s spatio-temporal coverage during the study period. The area increased significantly from 30.6% in the first decade (1977–1986) to 44.4% in the last (2006–2015). The spatiotemporal distribution of meteorological drought showed no significant negative trends in annual precipitation during 1977–2016, but the occurrence of hydrological droughts increased significantly in the period 1997–2016. The expansion of irrigated area, with more than 60% of rainfed agriculture replaced by irrigated agriculture (especially between 1997 and 2006), exerted substantial pressure on surface water and groundwater resources. Together, climate change, reduced river flow, and significant declines in groundwater level in major aquifers led to unsustainable use of water resources, a considerable reduction in irrigated area, and unsustainability in agricultural production in the period 2006–2015. Analysis of causes and effects of meteorological, hydrological, and agricultural drought in the area identified three clear stages: before 1997 being sustainable, 1997–2006 being transitional, and after 2006 being unsustainable. Full article

(This article belongs to the Section Water Resources Management, Policy and Governance)

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17 pages, 4274 KiB

Open AccessEditor’s ChoiceArticle

Multi-Objective Approach for Determining Optimal Sustainable Urban Drainage Systems Combination at City Scale. The Case of San Luis Potosí (México)

by Sergio Zubelzu, Leonor Rodríguez-Sinobas, Alvaro Sordo-Ward, Alan Pérez-Durán and Rodolfo Cisneros-Almazán

Water 2020, 12(3), 835; https://doi.org/10.3390/w12030835 - 16 Mar 2020

Cited by 5 | Viewed by 3603

Abstract

A method for determining the optimal Sustainable Urban Drainage Systems (SUDs) combination at city scale is presented in this paper. A comprehensive set of SUDs categories comprising infrastructures aimed at either detaining and locally reusing or infiltrating precipitation are considered. A volumetric water [...] Read more.

A method for determining the optimal Sustainable Urban Drainage Systems (SUDs) combination at city scale is presented in this paper. A comprehensive set of SUDs categories comprising infrastructures aimed at either detaining and locally reusing or infiltrating precipitation are considered. A volumetric water balance is proposed for modelling hydrological processes in urban catchments. A multi-criteria approach combining a cost function and aims for both recharging aquifers and limiting runoff contribution to water courses is proposed to find the optimal SUDs combination. The water balance was run with each possible SUDs combination and the optimal set of SUDs was found. The method was applied to the Metropolitan Area of San Luis Potosí (Mexico). The optimal solutions in this case clearly promoted surface runoff detention and reuse over porous pavements and green roofs but they were sensitive to the considered costs. The SUD requirements to potential new urban developments for each catchment to comply with the original hydrological aims were also studied. The method requires customizing the cost function and using representative climatic data. Full article

(This article belongs to the Special Issue Planning and Management of Hydraulic Infrastructure)

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22 pages, 2867 KiB

Open AccessEditor’s ChoiceArticle

Copula-Based Multivariate Frequency Analysis of the 2012–2018 Drought in Northeast Brazil

by João Dehon Pontes Filho, Francisco de Assis Souza Filho, Eduardo Sávio Passos Rodrigues Martins and Ticiana Marinho de Carvalho Studart

Water 2020, 12(3), 834; https://doi.org/10.3390/w12030834 - 16 Mar 2020

Cited by 57 | Viewed by 5259

Abstract

The 2012–2018 drought was such an extreme event in the drought-prone area of Northeast Brazil that it triggered a discussion about proactive drought management. This paper aims at understanding the causes and consequences of this event and analyzes its frequency. A consecutive sequence [...] Read more.

The 2012–2018 drought was such an extreme event in the drought-prone area of Northeast Brazil that it triggered a discussion about proactive drought management. This paper aims at understanding the causes and consequences of this event and analyzes its frequency. A consecutive sequence of sea surface temperature anomalies in the Pacific and Atlantic Oceans, at both the decadal and interannual scales, led to this severe and persistent drought. Drought duration and severity were analyzed using run theory at the hydrographic region scale as decision-makers understand impact analysis better at this scale. Copula functions were used to properly model drought joint characteristics as they presented different marginal distributions and an asymmetric behavior. The 2012–2018 drought in Ceará State had the highest mean bivariate return period ever recorded, estimated at 240 years. Considering drought duration and severity simultaneously at the level of the hydrographic regions improves risk assessment. This result advances our understanding of exceptional events. In this sense, the present work proposes the use of this analysis as a tool for proactive drought planning. Full article

(This article belongs to the Special Issue Management of Hydrological Extremes: Floods and Droughts)

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16 pages, 4445 KiB

Open AccessEditor’s ChoiceArticle

Hydrochemical Characteristics of Groundwater and Dominant Water–Rock Interactions in the Delingha Area, Qaidam Basin, Northwest China

by Biao Zhang, Dan Zhao, Pengpeng Zhou, Shen Qu, Fu Liao and Guangcai Wang

Water 2020, 12(3), 836; https://doi.org/10.3390/w12030836 - 16 Mar 2020

Cited by 91 | Viewed by 5170

Abstract

Groundwater is undoubtedly important for water supplies and eco-environment protection, especially for arid and semi-arid regions. Analyzing the characteristics and evolution of groundwater is significant for the rational management of groundwater resources. This study investigated the hydrogeochemical characteristics and evolutions of groundwater in [...] Read more.

Groundwater is undoubtedly important for water supplies and eco-environment protection, especially for arid and semi-arid regions. Analyzing the characteristics and evolution of groundwater is significant for the rational management of groundwater resources. This study investigated the hydrogeochemical characteristics and evolutions of groundwater in the Delingha area, northeast of the Qaidam Basin, northwest China, with a total of 123 water samples, including 105 unconfined groundwater samples, 12 confined groundwater samples, and 6 surface water samples. Hydrochemical results showed that the unconfined and confined groundwater presented diversity in ion concentration. Total Dissolved Solids (TDS) of the unconfined groundwater increased from 146.5 to 8954 mg/L along the groundwater flow direction. The groundwater hydrochemical types were HCO₃-Ca·Mg and HCO₃·SO₄-Ca·Mg in the mountain front area, SO₄·HCO₃-Ca·Mg and SO₄·Cl-Ca·Mg types in the alluvial-lacustrine plain, and Cl·SO₄-Na and Cl-Na types in the lacustrine plain. The saturation index showed that parts of the groundwater samples were supersaturated with carbonate minerals (calcite and dolomite); however, all the samples were undersaturated with evaporite minerals (halite and gypsum). Groundwater chemical evolution is mainly controlled by evaporite and carbonate mineral dissolutions, aluminosilicates weathering, and cation exchange. Full article

(This article belongs to the Section Water Quality and Contamination)

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21 pages, 600 KiB

Open AccessEditor’s ChoiceArticle

Unpacking Water Governance: A Framework for Practitioners

by Alejandro Jiménez, Panchali Saikia, Ricard Giné, Pilar Avello, James Leten, Birgitta Liss Lymer, Kerry Schneider and Robin Ward

Water 2020, 12(3), 827; https://doi.org/10.3390/w12030827 - 15 Mar 2020

Cited by 104 | Viewed by 20222

Abstract

Water governance has emerged as an important topic in the international arena and is acknowledged to be a crucial factor for adequate and sustained progress towards achieving Sustainable Development Goal (SDG) 6. However, there is not enough clarity about the practical meaning of [...] Read more.

Water governance has emerged as an important topic in the international arena and is acknowledged to be a crucial factor for adequate and sustained progress towards achieving Sustainable Development Goal (SDG) 6. However, there is not enough clarity about the practical meaning of the term “water governance” and how to work with it. This paper reviews the term’s use, to reveal how the concept is understood, referred to, and implemented in practice by different stakeholders. Based on literature review and consultations with experts, we identify and describe the core components of water governance (functions), describe their potential qualities when performed (attributes), and how they interrelate with the values and aspirations of the different stakeholders to achieve certain outcomes. These different components are described in detail to construct an operational framework to assess and work with water governance, which covers water and sanitation services delivery, water resources management and transboundary waters. This paper’s findings provide practical guidance for decision makers and practitioners on how action-oriented water governance processes can be meaningfully designed, and ultimately, how to strengthen efforts aiming to improve water governance. Full article

(This article belongs to the Special Issue Selected Papers from 2019 World Water Week)

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16 pages, 3376 KiB

Open AccessEditor’s ChoiceArticle

A Nonlinear Autoregressive Modeling Approach for Forecasting Groundwater Level Fluctuation in Urban Aquifers

by Abdullah A. Alsumaiei

Water 2020, 12(3), 820; https://doi.org/10.3390/w12030820 - 14 Mar 2020

Cited by 46 | Viewed by 4141

Abstract

The application of a nonlinear autoregressive modeling approach with exogenous input (NARX) neural networks for modeling groundwater level fluctuation has been examined by several researchers. However, the suitability of NARX in modeling groundwater level dynamics in urbanized and arid aquifer systems has not [...] Read more.

The application of a nonlinear autoregressive modeling approach with exogenous input (NARX) neural networks for modeling groundwater level fluctuation has been examined by several researchers. However, the suitability of NARX in modeling groundwater level dynamics in urbanized and arid aquifer systems has not been comprehensively investigated. In this study, a NARX-based modeling approach is presented to establish a robust water management tool to aid urban water managers in controlling the development of shallow water tables induced by artificial recharge activity. Temperature data series are used as exogenous inputs for the NARX network, as they better reflect the intensity of artificial recharge activities, such as excessive lawns irrigation. Input delays and feedback delays for the NARX networks are determined based on the autocorrelation and cross-correlation analyses of detrended groundwater levels and monthly temperature averages. The validation of the proposed approach is assessed through a rolling validation procedure. Four observation wells in Kuwait City are selected to test the applicability of the proposed approach. The results showed the superiority of the NARX-based approach in modeling groundwater levels in such an urbanized and arid aquifer system, with coefficient of determination (R²) values ranging between 0.762 and 0.994 in the validation period. Comparison with other statistical models applied to the same study area shows that NARX models presented here reduced the mean absolute error (MAE) of groundwater levels forecasts by 50%. The findings of this paper are promising and provide a valuable tool for the urban city planner to assist in controlling the problem of shallow water tables for similar climatic and aquifer systems. Full article

(This article belongs to the Section Urban Water Management)

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23 pages, 3266 KiB

Open AccessEditor’s ChoiceArticle

Lithological and Tectonic Control on Groundwater Contribution to Stream Discharge During Low-Flow Conditions

by Stefanie B. Wirth, Claire Carlier, Fabien Cochand, Daniel Hunkeler and Philip Brunner

Water 2020, 12(3), 821; https://doi.org/10.3390/w12030821 - 14 Mar 2020

Cited by 17 | Viewed by 4285

Abstract

Knowing how stream discharge in an ungauged catchment reacts to dry spells is a major challenge for managing water resources. The role of geology on these dynamics is poorly understood. For the Swiss Molasse basin, we therefore explored how the geology influences the [...] Read more.

Knowing how stream discharge in an ungauged catchment reacts to dry spells is a major challenge for managing water resources. The role of geology on these dynamics is poorly understood. For the Swiss Molasse basin, we therefore explored how the geology influences the groundwater contribution to stream flow during low-flow conditions. Using existing data from geological reports and maps as well as from deep boreholes, we constructed a basin-wide overview of the hydrogeological quality of the bedrock and investigated five catchments in 3D. We found that catchments with the most permeable sedimentary bedrock are least sensitive to low flows (marine sandstone, K = 10⁻⁴ to 10⁻⁵ m/s, P_eff = 5–10%). In contrast, if bedrock K is low (K < 10⁻⁶ m/s), the presence of a productive Quaternary volume becomes decisive for groundwater contribution to stream flow. Limitations exist due to a restricted database for K and P_eff values of the Molasse and limited information on continuation of lithologies with depth. This emphasizes the need for more hydrogeologically relevant data for the future management of water resources. Our results highlighting what lithotypes favor groundwater contribution to stream flow are valid also in other regions for the assessment of a catchment’s sensitivity to low flows. Full article

(This article belongs to the Section Water Resources Management, Policy and Governance)

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16 pages, 2743 KiB

Open AccessEditor’s ChoiceArticle

Quantile Mapping Bias Correction on Rossby Centre Regional Climate Models for Precipitation Analysis over Kenya, East Africa

by Brian Ayugi, Guirong Tan, Niu Ruoyun, Hassen Babaousmail, Moses Ojara, Hanggoro Wido, Lucia Mumo, Nadoya Hamida Ngoma, Isaac Kwesi Nooni and Victor Ongoma

Water 2020, 12(3), 801; https://doi.org/10.3390/w12030801 - 13 Mar 2020

Cited by 41 | Viewed by 6895

Abstract

This study uses the quantile mapping bias correction (QMBC) method to correct the bias in five regional climate models (RCMs) from the latest output of the Rossby Center Climate Regional Model (RCA4) over Kenya. The outputs were validated using various scalar metrics such [...] Read more.

This study uses the quantile mapping bias correction (QMBC) method to correct the bias in five regional climate models (RCMs) from the latest output of the Rossby Center Climate Regional Model (RCA4) over Kenya. The outputs were validated using various scalar metrics such as root-mean-square difference (RMSD), mean absolute error (MAE), and mean bias. The study found that the QMBC algorithm demonstrates varying performance among the models in the study domain. The results show that most of the models exhibit reasonable improvement after corrections at seasonal and annual timescales. Specifically, the European Community Earth-System (EC-EARTH) and Commonwealth Scientific and Industrial Research Organization (CSIRO) models depict remarkable improvement as compared to other models. On the contrary, the Institute Pierre Simon Laplace Model CM5A-MR (IPSL-CM5A-MR) model shows little improvement across the rainfall seasons (i.e., March–May (MAM) and October–December (OND)). The projections forced with bias-corrected historical simulations tallied observed values demonstrate satisfactory simulations as compared to the uncorrected RCMs output models. This study has demonstrated that using QMBC on outputs from RCA4 is an important intermediate step to improve climate data before performing any regional impact analysis. The corrected models may be used in projections of drought and flood extreme events over the study area. Full article

(This article belongs to the Section Hydrology)

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18 pages, 2685 KiB

Open AccessEditor’s ChoiceArticle

Net Ecosystem Production of a River Relying on Hydrology, Hydrodynamics and Water Quality Monitoring Stations

by Fernando Rojano, David H Huber, Ifeoma R Ugwuanyi, Vadesse Lhilhi Noundou, Andrielle Larissa Kemajou-Tchamba and Jesus E Chavarria-Palma

Water 2020, 12(3), 783; https://doi.org/10.3390/w12030783 - 12 Mar 2020

Cited by 5 | Viewed by 4106

Abstract

Flow and water quality of rivers are highly dynamic. Water quantity and quality are subjected to simultaneous physical, chemical and biological processes making it difficult to accurately assess lotic ecosystems. Our study investigated net ecosystem production (NEP) relying on high-frequency data of hydrology, [...] Read more.

Flow and water quality of rivers are highly dynamic. Water quantity and quality are subjected to simultaneous physical, chemical and biological processes making it difficult to accurately assess lotic ecosystems. Our study investigated net ecosystem production (NEP) relying on high-frequency data of hydrology, hydrodynamics and water quality. The Kanawha River, West Virginia was investigated along 52.8 km to estimate NEP. Water quality data were collected along the river using three distributed multiprobe sondes that measured water temperature, dissolved oxygen, dissolved oxygen saturation, specific conductance, turbidity and ORP hourly for 71 days. Flows along the river were predicted by means of the hydrologic and hydrodynamic models in Hydrologic Simulation Program in Fortran (HSPF). It was found that urban local inflows were correlated with NEP. However, under hypoxic conditions, local inflows were correlated with specific conductance. Thus, our approach represents an effort for the systematic integration of data derived from models and field measurements with the aim of providing an improved assessment of lotic ecosystems. Full article

(This article belongs to the Special Issue Integrated Water Resources Research: Advancements in Understanding to Improve Future Sustainability)

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19 pages, 4455 KiB

Open AccessEditor’s ChoiceArticle

Trend in Extreme Precipitation Indices Based on Long Term In Situ Precipitation Records over Pakistan

by Asher Samuel Bhatti, Guojie Wang, Waheed Ullah, Safi Ullah, Daniel Fiifi Tawia Hagan, Isaac Kwesi Nooni, Dan Lou and Irfan Ullah

Water 2020, 12(3), 797; https://doi.org/10.3390/w12030797 - 12 Mar 2020

Cited by 68 | Viewed by 7397

Abstract

Assessing the long-term precipitation changes is of utmost importance for understanding the impact of climate change. This study investigated the variability of extreme precipitation events over Pakistan on the basis of daily precipitation data from 51 weather stations from 1980-2016. The non-parametric Mann–Kendall, [...] Read more.

Assessing the long-term precipitation changes is of utmost importance for understanding the impact of climate change. This study investigated the variability of extreme precipitation events over Pakistan on the basis of daily precipitation data from 51 weather stations from 1980-2016. The non-parametric Mann–Kendall, Sen’s slope estimator, least squares method, and two-tailed simple t-test methods were used to assess the trend in eight precipitation extreme indices. These indices were wet days (R1 ≥1 mm), heavy precipitation days (R10 ≥ 10 mm), very heavy precipitation days (R20 ≥ 20 mm), severe precipitation (R50 ≥ 50 mm), very wet days (R95p) defining daily precipitation ≥ 95 percentile, extremely wet days (R99p) defining daily precipitation ≥ 99 percentile, annual total precipitation in wet days (PRCPTOT), and mean precipitation amount on wet days as simple daily intensity index (SDII). The study is unique in terms of using high stations’ density, extended temporal coverage, advanced statistical techniques, and additional extreme indices. Furthermore, this study is the first of its kind to detect abrupt changes in the temporal trend of precipitation extremes over Pakistan. The results showed that the spatial distribution of trends in different precipitation extreme indices over the study region increased as a whole; however, the monsoon and westerlies humid regions experienced a decreasing trend of extreme precipitation indices during the study period. The results of the sequential Mann–Kendall (SqMK) test showed that all precipitation extremes exhibited abrupt dynamic changes in temporal trend during the study period; however, the most frequent mutation points with increasing tendency were observed during 2011 and onward. The results further illustrated that the linear trend of all extreme indices showed an increasing tendency from 1980- 2016. Similarly, for elevation, most of the precipitation extremes showed an inverse relationship, suggesting a decrease of precipitation along the latitudinal extent of the country. The spatiotemporal variations in precipitation extremes give a possible indication of the ongoing phenomena of climate change and variability that modified the precipitation regime of Pakistan. On the basis of the current findings, the study recommends that future studies focus on underlying physical and natural drivers of precipitation variability over the study region. Full article

(This article belongs to the Section Water Use and Scarcity)

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16 pages, 2086 KiB

Open AccessEditor’s ChoiceArticle

Influence of Local Habitat and Climatic Factors on the Distribution of Fish Species in the Tonle Sap Lake

by Bunyeth Chan, Sébastien Brosse, Zeb S. Hogan, Peng Bun Ngor and Sovan Lek

Water 2020, 12(3), 786; https://doi.org/10.3390/w12030786 - 12 Mar 2020

Cited by 19 | Viewed by 6821

Abstract

Tonle Sap Lake (TSL) is a highly productive system and hosts a high fish diversity and is of paramount importance for sustaining protein supply for over 15 million Cambodians. Nevertheless, the ecology and factors influencing the spatial distribution of many fishes within the [...] Read more.

Tonle Sap Lake (TSL) is a highly productive system and hosts a high fish diversity and is of paramount importance for sustaining protein supply for over 15 million Cambodians. Nevertheless, the ecology and factors influencing the spatial distribution of many fishes within the lake remain poorly understood. Using commercial fishing lot catch data from 1994/1995 to 1999/2000, fishing seasons and environmental data (land cover and bioclimatic variables), we describe spatial distribution of the eight most commercially important fish species, and investigate the effects of environmental factors on their distributions in the TSL. We found a strong variability in fish biomass across areas and between species. Specifically, Channa micropeltes was most abundant in the southern and northern sections of the TSL. Channa striata and Trichopodus microlepis were more common in the northern part of the TSL. Cyclocheilos enoplos, Barbonymus gonionotus, Pangasianodon hypophthalmus, and Gymnostomus spp. were abundant in the southern areas of the TSL while Phalacronotus spp. were abundant in few areas in both the north and the south. Flooded forest positively explained the variation in the biomass of P. hypophthalmus, C. striata, C. enopolos, and Phalacronotus spp. Likewise, the lake’s open water positively affects the biomass of P. hypophthalmus, C. enopolos, and Phalacronotus spp., while the agricultural field negatively impacts Gymnostomus spp. biomass distribution. We also found that some areas consistently hosted high fish biomass (e.g., lot 2, Kampong Thom; lot 6, Pursat; lot 2, Battambang, etc.). We, therefore, suggest that fisheries management and conservation planning focus on those areas, considering those areas significance as core fish habitat and important for catching fish. Full article

(This article belongs to the Special Issue Channels for Change: Integrating Multiple Disciplines for New Frontiers in Managing the Mekong River Basin)

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32 pages, 4941 KiB

Open AccessEditor’s ChoiceArticle

Using the Freshwater Health Index to Assess Hydropower Development Scenarios in the Sesan, Srepok and Sekong River Basin

by Nicholas J. Souter, Kashif Shaad, Derek Vollmer, Helen M. Regan, Tracy A. Farrell, Mike Arnaiz, Peter-John Meynell, Thomas A. Cochrane, Mauricio E. Arias, Thanapon Piman and Sandy J. Andelman

Water 2020, 12(3), 788; https://doi.org/10.3390/w12030788 - 12 Mar 2020

Cited by 13 | Viewed by 7693

Abstract

Sustainable water resource management is a wicked problem, fraught with uncertainties, an indeterminate scope, and divergent social values and interests among stakeholders. To facilitate better management of Southeast Asia’s transboundary Sesan, Sekong and Srepok (3S) River basin, we used the Freshwater Health Index [...] Read more.

Sustainable water resource management is a wicked problem, fraught with uncertainties, an indeterminate scope, and divergent social values and interests among stakeholders. To facilitate better management of Southeast Asia’s transboundary Sesan, Sekong and Srepok (3S) River basin, we used the Freshwater Health Index (FHI) to diagnose the basin’s current and likely future level of freshwater health. We used the conditions for December 2016 as a baseline, where Ecosystem Vitality and Ecosystem Services scored 66 and 80, respectively, out of a possible 100, whilst Governance & Stakeholders scored 43. Thus, the 3S provided a range of desired ecosystem services, but there were signs of environmental stress as well as undeveloped water governance systems and limited stakeholder engagement. We also modelled four hydropower development scenarios and found that increasing development reduced the scores of a subset of indicators. This compromised the future ability of the 3S basin’s ecosystem to provide its current range of services. The FHI helped identify data deficiencies, illuminated important social dynamics, made ecosystem–human–water dynamics more understandable to stakeholders, and examined the long-term dynamics of the basin. Full article

(This article belongs to the Special Issue Channels for Change: Integrating Multiple Disciplines for New Frontiers in Managing the Mekong River Basin)

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16 pages, 2427 KiB

Open AccessEditor’s ChoiceArticle

Treatment of Produced Water in the Permian Basin for Hydraulic Fracturing: Comparison of Different Coagulation Processes and Innovative Filter Media

by Alfredo Zendejas Rodriguez, Huiyao Wang, Lei Hu, Yanyan Zhang and Pei Xu

Water 2020, 12(3), 770; https://doi.org/10.3390/w12030770 - 11 Mar 2020

Cited by 57 | Viewed by 8111

Abstract

Produced water is the largest volume of waste product generated during oil and natural gas exploration and production. The traditional method to dispose of produced water involves deep well injection, but this option is becoming more challenging due to high operational cost, limited [...] Read more.

Produced water is the largest volume of waste product generated during oil and natural gas exploration and production. The traditional method to dispose of produced water involves deep well injection, but this option is becoming more challenging due to high operational cost, limited disposal capacity, and more stringent regulations. Meanwhile, large volumes of freshwater are used for hydraulic fracturing. The goal of this study is to develop cost-effective technologies, and optimize system design and operation to treat highly saline produced water (120–140 g/L total dissolved solids) for hydraulic fracturing. Produced water was collected from a salt water disposal facility in the Permian Basin, New Mexico. Chemical coagulation (CC) using ferric chloride and aluminum sulfate as coagulants was compared with electrocoagulation (EC) with aluminum electrodes for removal of suspended contaminants. The effects of coagulant dose, current density, and hydraulic retention time during EC on turbidity removal were investigated. Experimental results showed that aluminum sulfate was more efficient and cost-effective than ferric chloride for removing turbidity from produced water. The optimal aluminum dose was achieved at operating current density of 6.60 mA/cm² and 12 min contact time during EC treatment, which resulted in 74% removal of suspended solids and 53–78% removal of total organic carbon (TOC). The energy requirement of EC was calculated 0.36 kWh/m³ of water treated. The total operating cost of EC was estimated $0.44/m³ of treated water, which is 1.7 or 1.2 times higher than CC using alum or ferric chloride as the coagulant, respectively. The EC operating cost was primarily associated with the consumption of aluminum electrode materials due to faradaic reactions and electrodes corrosions. EC has the advantage of shorter retention time, in situ production of coagulants, less sludge generation, and high mobility for onsite produced water treatment. The fine particles and other contaminants after coagulation were further treated in continuous-flow columns packed with different filter media, including agricultural waste products (pecan shell, walnut shell, and biochar), and new and spent granular activated carbon (GAC). Turbidity, TOC, metals, and electrical conductivity were monitored to evaluate the performance of the treatment system and the adsorption capacities of different media. Biochar and GAC showed the greatest removal of turbidity and TOC in produced water. These treatment technologies were demonstrated to be effective for the removal of suspended constituents and iron, and to produce a clean brine for onsite reuse, such as hydraulic fracturing. Full article

(This article belongs to the Special Issue Advanced Technologies for Produced Water Management, Treatment, and Reuse)

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24 pages, 9625 KiB

Open AccessEditor’s ChoiceArticle

Addressing the Water–Energy Nexus by Coupling the Hydrological Model with a New Energy LISENGY Model: A Case Study in the Iberian Peninsula

by Marko Adamovic, Emiliano Gelati, Berny Bisselink and Ad De Roo

Water 2020, 12(3), 762; https://doi.org/10.3390/w12030762 - 10 Mar 2020

Cited by 3 | Viewed by 3331

Abstract

As water is required for producing hydropower, and subsequently the water balance is changed for downstream areas, the linking of hydrological and energy models is needed to properly address the interactions among them. In this study, volume–depth-based water storage estimation models were proposed [...] Read more.

As water is required for producing hydropower, and subsequently the water balance is changed for downstream areas, the linking of hydrological and energy models is needed to properly address the interactions among them. In this study, volume–depth-based water storage estimation models were proposed for individual lakes and reservoirs in the Iberian Peninsula using the 30-year Global Water Surface dataset and reservoir morphometry methodology which enables to evaluate reservoirs where data were not available before. The models were subsequently implemented within the new hydropower model called LISENGY that provides the first comprehensive assessment of the temporal and spatial dynamics of water storage, water depth and hydropower production in the Iberian Peninsula. The LISENGY model was coupled with the distributed LISFLOOD hydrological model. The seasonal and interannual changes in energy production were assessed for 168 studied reservoirs with diverse morphometries, which is unique. Conical, concave and convex regression reservoir relationships were distinguished, and optimized turbine discharge and power production were computed. A 10-year water–energy linked system for the 2007–2016 period has been established for the Iberian Peninsula which was not available before. The results showed that it is possible to connect those two models and that the timing and magnitude of simulated storage were well reproduced. The study represents the first step towards integrated pan-European water–energy modeling. Future climate scenarios and energy demands are to be fed into the linked model system to evaluate expected future hydropower generation and possible water scarcity issues. Full article

(This article belongs to the Section Water, Agriculture and Aquaculture)

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36 pages, 2603 KiB

Open AccessEditor’s ChoiceArticle

Assessment of Water Security in Socially Excluded Areas in Kolkata, India: An Approach Focusing on Water, Sanitation and Hygiene

by Subham Mukherjee, Trude Sundberg and Brigitta Schütt

Water 2020, 12(3), 746; https://doi.org/10.3390/w12030746 - 8 Mar 2020

Cited by 21 | Viewed by 12699

Abstract

Water security is essential not only to ensure the availability and accessibility of water for drinking, producing food, washing, but also to maintain both human and environmental health. The 2011 Census of India reveals that 17.4% of urban households in India live in [...] Read more.

Water security is essential not only to ensure the availability and accessibility of water for drinking, producing food, washing, but also to maintain both human and environmental health. The 2011 Census of India reveals that 17.4% of urban households in India live in deprived areas in urban landscapes which are designated as slums in the Census dataset. The increasing number of people living in these areas poses serious challenges to the provision of basic urban water, sanitation and hygiene (WaSH) services. Perceived susceptibility of risks from contaminated water and lack of proper sanitation and hygiene will be addressed in the light of social exclusion factors. This study attempts to assess the present situation of water, sanitation and required hygiene provisions within the areas defined as slums by the Census of India 2011 in Kolkata, India. Based on the results obtained from the datasets from the census, and a household survey, we identified a lack of supplies associated with WaSH provisions in these areas of Kolkata. The WaSH provisions in the slum areas of Kolkata city are facing various issues related to regularity, quality and quantity of supplied water. Additionally, there is poor maintenance of existing WaSH services including latrine facilities and per capita allocation of a sustainable water security among the slum dwellers. By adding to our understanding of the importance of factors such as gender, religions, and knowledge of drinking water in deprived areas, the study analyses the links between both physical and social issues determining vulnerability and presence of deprivation associated with basic WaSH provisions as human rights of slum communities. Full article

(This article belongs to the Section Urban Water Management)

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17 pages, 5700 KiB

Open AccessEditor’s ChoiceArticle

A New Approach to Permeability Inversion of Fractured Rock Masses and Its Engineering Application

by Lei Gan, Guanyun Chen and Zhenzhong Shen

Water 2020, 12(3), 734; https://doi.org/10.3390/w12030734 - 7 Mar 2020

Cited by 14 | Viewed by 3341

Abstract

This paper presents a new seepage inversion technique to predict the permeability coefficient of the rock mass with developed fracture or fault. With the measured data of flow and water head of boreholes, the permeability coefficient of the rock masses near the boreholes [...] Read more.

This paper presents a new seepage inversion technique to predict the permeability coefficient of the rock mass with developed fracture or fault. With the measured data of flow and water head of boreholes, the permeability coefficient of the rock masses near the boreholes are obtained by inverse calculation on the basis of unsteady seepage tests. Then, a flexible tolerance method is proposed to invert the permeability coefficient of rock masses in different zones of the reservoir area. This comprehensive inversion analysis method is applied in one actual project of the water supply reservoir. The equivalent permeability coefficient of the rock masses in the range of 0 m to 16.0 m below the road surface near the dam axis on the left bank of the mountain is 1.12 × 10⁻³ cm/s. The root mean squared error and coefficient of determination of the measured and calculated values are 1.33 × 10⁻⁴ m³/s and 0.9976 m³/s, respectively. The rock masses in the reservoir site area have high permeability. The groundwater level in the junction area and the mountains on both sides of Shangmo reservoir is low, and the hydraulic gradient is small. The maximum error between the calculated value of the groundwater level and the measured values is −0.41 m, and the relative error is −4.36%. The recommended anti-seepage scheme can effectively solve the problem of large leakage in the reservoir area. The results show that the innovative approach is appropriate for the seepage analysis of the field with the fractured rock masses and more meaningful from an engineering point of view. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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