Water

Article

13 pages, 2054 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Comparison between the Lagrangian and Eulerian Approach in Simulation of Free Surface Air-Core Vortices

by Maryam Azarpira, Amir Reza Zarrati and Pouya Farrokhzad

Water 2021, 13(5), 726; https://doi.org/10.3390/w13050726 - 7 Mar 2021

Cited by 8 | Viewed by 7497

The problematic consequences regarding formation of air-core vortices at the intakes and the drastic necessity of a thorough investigation into the phenomenon has resulted in particular attention being placed on Computational Fluid Dynamics (CFD) as an economically viable method. Two main approaches could [...] Read more.

The problematic consequences regarding formation of air-core vortices at the intakes and the drastic necessity of a thorough investigation into the phenomenon has resulted in particular attention being placed on Computational Fluid Dynamics (CFD) as an economically viable method. Two main approaches could be taken using CFD, namely the Eulerian and Lagrangian methods each of which is characterized by specific advantages and disadvantages. Whereas many researchers have used the Eulerian approach for vortex simulation, the Lagrangian approach has not been found in the literature. The present study dealt with the comparison of the Lagrangian and Eulerian approaches in the simulation of vortex flow. Simulations based on both approaches were carried out by solving the Navier–Stokes equations accompanied by the LES turbulence model. The results of the numerical model were evaluated in accordance with a physical model for steady vortex flow using particle image velocimetry (PIV), revealing that both approaches are sufficiently capable of simulating the vortex flow but with the difference that the Lagrangian method has greater computational cost with less accuracy. Full article

(This article belongs to the Special Issue Computational Fluid Mechanics and Hydraulics)

► Show Figures

Figure 1

22 pages, 3422 KiB

Open AccessEditor’s ChoiceArticle

Construction of Critical Periods for Water Resources Management and Their Application in the FEW Nexus

by Val Z. Schull, Sushant Mehan, Margaret W. Gitau, David R. Johnson, Shweta Singh, Juan P. Sesmero and Dennis C. Flanagan

Water 2021, 13(5), 718; https://doi.org/10.3390/w13050718 - 6 Mar 2021

Cited by 3 | Viewed by 3382

Abstract

Amidst the growing population, urbanization, globalization, and economic growth, along with the impacts of climate change, decision-makers, stakeholders, and researchers need tools for better assessment and communication of the highly interconnected food–energy–water (FEW) nexus. This study aimed to identify critical periods for water [...] Read more.

Amidst the growing population, urbanization, globalization, and economic growth, along with the impacts of climate change, decision-makers, stakeholders, and researchers need tools for better assessment and communication of the highly interconnected food–energy–water (FEW) nexus. This study aimed to identify critical periods for water resources management for robust decision-making for water resources management at the nexus. Using a 4610 ha agricultural watershed as a pilot site, historical data (2006–2012), scientific literature values, and SWAT model simulations were utilized to map out critical periods throughout the growing season of corn and soybeans. The results indicate that soil water deficits are primarily seen in June and July, with average deficits and surpluses ranging from −134.7 to +145.3 mm during the study period. Corresponding water quality impacts include average monthly surface nitrate-N, subsurface nitrate-N, and soluble phosphorus losses of up to 0.026, 0.26, and 0.0013 kg/ha, respectively, over the growing season. Estimated fuel requirements for the agricultural practices ranged from 24.7 to 170.3 L/ha, while estimated carbon emissions ranged from 0.3 to 2.7 kg CO₂/L. A composite look at all the FEW nexus elements showed that critical periods for water management in the study watershed occurred in the early and late season—primarily related to water quality—and mid-season, related to water quantity. This suggests the need to adapt agricultural and other management practices across the growing season in line with the respective water management needs. The FEW nexus assessment methodologies developed in this study provide a framework in which spatial, temporal, and literature data can be implemented for improved water resources management in other areas. Full article

(This article belongs to the Special Issue The Water-Energy-Food Nexus: Sustainable Development)

► Show Figures

Figure 1

18 pages, 4720 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Urban Groundwater Contamination by Non-Steroidal Anti-Inflammatory Drugs

by Anna Jurado, Enric Vázquez-Suñé and Estanislao Pujades

Water 2021, 13(5), 720; https://doi.org/10.3390/w13050720 - 6 Mar 2021

Cited by 25 | Viewed by 3487

Abstract

Pharmaceuticals, such as non-steroidal anti-inflammatory drugs (NSAIDs) and their metabolites, have become a major concern due to their increasing consumption and their widespread occurrence in the environment. In this paper, we investigate the occurrence of NSAIDs and their metabolites in an urban aquifer, [...] Read more.

Pharmaceuticals, such as non-steroidal anti-inflammatory drugs (NSAIDs) and their metabolites, have become a major concern due to their increasing consumption and their widespread occurrence in the environment. In this paper, we investigate the occurrence of NSAIDs and their metabolites in an urban aquifer, which may serve as a potential resource for drinking water, and propose a methodology to assess the removal of these substances in the river–groundwater interface. Then, risk quotients (RQs) are computed, in order to determine the risk posed by the single NSAIDs and their mixture to human health. To this end, six NSAIDs and two metabolites were collected from an urban aquifer located in the metropolitan area of Barcelona (NE, Spain), in which the major pollution source is a contaminated river. All of the target NSAIDs were detected in groundwater samples, where the concentrations in the aquifer were higher than those found in the river water (except for ibuprofen). Diclofenac, ketoprofen, propyphenazone and salicylic acid were detected at high mean concentrations (ranging from 91.8 ng/L to 225.2 ng/L) in the aquifer. In contrast, phenazone and mefenamic acid were found at low mean concentrations (i.e., lower than 25 ng/L) in the aquifer. According to the proposed approach, the mixing of river water recharge into the aquifer seemed to some extent to promote the removal of the NSAIDs under the sub-oxic to denitrifying conditions found in the groundwater. The NSAIDs that presented higher mean removal values were 4OH diclofenac (0.8), ibuprofen (0.78), salicylic acid (0.35) and diclofenac (0.28), which are likely to be naturally attenuated under the aforementioned redox conditions. Concerning human health risk assessment, the NSAIDs detected in groundwater and their mixture do not pose any risk for all age intervals considered, as the associated RQs were all less than 0.05. Nevertheless, this value must be taken with caution, as many pharmaceuticals might occur simultaneously in the groundwater. Full article

(This article belongs to the Special Issue Urban Groundwater)

► Show Figures

Figure 1

25 pages, 25677 KiB

Open AccessEditor’s ChoiceArticle

Evaluation of Water Social Service and Comprehensive Water Management Linked with Integrated River Evaluation

by Da Ye Kim, Su Hee Park and Chul Min Song

Water 2021, 13(5), 706; https://doi.org/10.3390/w13050706 - 5 Mar 2021

Cited by 7 | Viewed by 1989

Abstract

Various factors like climate change and population increase have limited water management evaluation. In South Korea particularly, although the management of water quality and water quantity has recently been integrated, a comprehensive policy has not yet been identified. This study, therefore, aims to [...] Read more.

Various factors like climate change and population increase have limited water management evaluation. In South Korea particularly, although the management of water quality and water quantity has recently been integrated, a comprehensive policy has not yet been identified. This study, therefore, aims to propose a methodology for evaluating water social service for 18 basins near major water resources in South Korea. It aims to promote advanced water resource management, secure water equity, and improve inadequate policy implementation. In addition, it proposes a methodology for comprehensive water management evaluation linked with integrated river evaluation with respect to water quality and water quantity. Accordingly, contrary to the common assumption that the entire population has easy access to the supplied water, the status of water service was assessed objectively. The status of water management per sector was also visually represented, through which the vulnerabilities of water management could be intuitively diagnosed. Based on the possibility of utilizing the study results to determine the basic direction for water management, the methodology of this study has been proposed as a tool for establishing an efficient water management policy. Full article

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

► Show Figures

Figure 1

25 pages, 17640 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Numerical Study on the Hydraulic Properties of Flow over Different Pooled Stepped Spillways

by Amir Ghaderi, Saeed Abbasi and Silvia Di Francesco

Water 2021, 13(5), 710; https://doi.org/10.3390/w13050710 - 5 Mar 2021

Cited by 19 | Viewed by 3180

Abstract

This work presents numerical simulations carried out to study the influence of geometric characteristics of pooled steps on the energy dissipation performance, flow patterns properties, velocity rates, and pressure distributions over a spillway. The localization of the inception point of air entrainment was [...] Read more.

This work presents numerical simulations carried out to study the influence of geometric characteristics of pooled steps on the energy dissipation performance, flow patterns properties, velocity rates, and pressure distributions over a spillway. The localization of the inception point of air entrainment was also assessed, being a key design parameter of spillways. With this aim, different configurations of steps were taken in account, including flat, pooled, and notch pooled types. The computational procedure was first validated with experimental results from the literature and then used to test the hydraulic behavior derived from different geometric configurations. The flat step configuration showed the best energy dissipation performance as compared with other configurations. With the notched pooled step configuration, the efficiency performance of the pooled structure improved by about 5.8%. The interfacial velocities of the flat stepped spillway were smaller than those of the pooled structure. The pressure value at the beginning of the step in the pooled configuration was larger than the flat configuration, while for the notched pool the maximum pressure values decreased near the step pool. Pool configuration (simple or notched) did not have a significant influence on the location of air entrainment. Full article

(This article belongs to the Special Issue Ecohydraulics Modeling and Simulation)

► Show Figures

Figure 1

27 pages, 26491 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Incorporating the Effects of Complex Soil Layering and Thickness Local Variability into Distributed Landslide Susceptibility Assessments

by Francesco Fusco, Benjamin B. Mirus, Rex L. Baum, Domenico Calcaterra and Pantaleone De Vita

Water 2021, 13(5), 713; https://doi.org/10.3390/w13050713 - 5 Mar 2021

Cited by 21 | Viewed by 2963

Abstract

Incorporating the influence of soil layering and local variability into the parameterizations of physics-based numerical models for distributed landslide susceptibility assessments remains a challenge. Typical applications employ substantial simplifications including homogeneous soil units and soil-hydraulic properties assigned based only on average textural classifications; [...] Read more.

Incorporating the influence of soil layering and local variability into the parameterizations of physics-based numerical models for distributed landslide susceptibility assessments remains a challenge. Typical applications employ substantial simplifications including homogeneous soil units and soil-hydraulic properties assigned based only on average textural classifications; the potential impact of these assumptions is usually disregarded. We present a multi-scale approach for parameterizing the distributed Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability (TRIGRS) model that accounts for site-specific spatial variations in both soil thickness and complex layering properties by defining homogeneous soil properties that vary spatially for each model grid cell. These effective properties allow TRIGRS to accurately simulate the timing and distribution of slope failures without any modification of the model structure. We implemented this approach for the carbonate ridge of Sarno Mountains (southern Italy) whose slopes are mantled by complex layered soils of pyroclastic origin. The urbanized foot slopes enveloping these mountains are among the most landslide-prone areas of Italy and have been subjected to repeated occurrences of damaging and deadly rainfall-induced flow-type shallow landslides. At this scope, a primary local-scale application of TRIGRS was calibrated on physics-based rainfall thresholds, previously determined by a coupled VS2D (version 1.3) hydrological modeling and slope stability analysis. Subsequently, by taking into account the spatial distribution of soil thickness and vertical heterogeneity of soil hydrological and mechanical properties, a distributed assessment of landslide hazard was carried out by means of TRIGRS. The combination of these approaches led to the spatial assessment of landslide hazard under different hypothetical rainfall intensities and antecedent hydrological conditions. This approach to parameterizing TRIGRS can be adapted to other spatially variable soil layering and thickness to improve hazard assessments. Full article

(This article belongs to the Special Issue Rainfall-Induced Shallow Landslides Modeling and Warning)

► Show Figures

Figure 1

15 pages, 4110 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Influence of Groundwater Discharge on Temporal Evolution in Two Wetlands of an Intensely Anthropized Area: Analysis Using an Integrated Approach

by Francisco Sánchez-Martos, José Manuel López-Martos, Luis Molina Sánchez, Juan Gisbert-Gallego and Francisco Navarro-Martínez

Water 2021, 13(5), 697; https://doi.org/10.3390/w13050697 - 5 Mar 2021

Cited by 2 | Viewed by 2342

Abstract

The Campo de Dalías is a coastal plain, which has undergone a significant change in land use and intensive exploitation of groundwater. A series of diverse data has been analyzed: aerial and satellite images (1956–2013), evolution of the water table (1973–2019), and exploitation [...] Read more.

The Campo de Dalías is a coastal plain, which has undergone a significant change in land use and intensive exploitation of groundwater. A series of diverse data has been analyzed: aerial and satellite images (1956–2013), evolution of the water table (1973–2019), and exploitation of different aquifers (1964–2017). The results indicate: (1) increase in the surface area occupied by greenhouses, (2) increase in abstraction of groundwater, and (3) an opposite trend in the piezometric evolution of the two aquifers (deep and shallow). All this has had a significant effect on the evolution of the “Punta Entinas” wetland, which has shown a continuous increase in flooded surface area, especially pronounced since 1994. Its waters have intermediate hydrochemical characteristics between seawater and groundwater and reflect the local influence of groundwater on the wetland. The applied methodology is useful in areas with sustained human activity, land use changes, and intensive groundwater exploitation, and can contribute to the understanding of surface water-groundwater dependence and wetland management. Full article

(This article belongs to the Special Issue Advances in the Study and Understanding of Groundwater Discharge to Surface Water)

► Show Figures

Figure 1

16 pages, 7584 KiB

Open AccessEditor’s ChoiceArticle

Integrating GIS-Based MCDA Techniques and the SCS-CN Method for Identifying Potential Zones for Rainwater Harvesting in a Semi-Arid Area

by Hussein Al-Ghobari and Ahmed Z. Dewidar

Water 2021, 13(5), 704; https://doi.org/10.3390/w13050704 - 5 Mar 2021

Cited by 35 | Viewed by 4723

Abstract

An increasing scarcity of water, as well as rapid global climate change, requires more effective water conservation alternatives. One promising alternative is rainwater harvesting (RWH). Nevertheless, the evaluation of RWH potential together with the selection of appropriate sites for RWH structures is significantly [...] Read more.

An increasing scarcity of water, as well as rapid global climate change, requires more effective water conservation alternatives. One promising alternative is rainwater harvesting (RWH). Nevertheless, the evaluation of RWH potential together with the selection of appropriate sites for RWH structures is significantly difficult for the water managers. This study deals with this difficulty by identifying RWH potential areas and sites for RWH structures utilizing geospatial and multi-criteria decision analysis (MCDA) techniques. The conventional data and remote sensing data were employed to set up needed thematic layers using ArcGIS software. The soil conservation service curve number (SCS-CN) method was used to determine surface runoff, centered on which yearly runoff potential map was produced in the ArcGIS environment. Thematic layers such as drainage density, slope, land use/cover, and runoff were allotted appropriate weights to produced RWH potential areas and zones appropriate for RWH structures maps of the study location. Results analysis revealed that the outcomes of the spatial allocation of yearly surface runoff depth ranging from 83 to 295 mm. Moreover, RWH potential areas results showed that the study areas can be categorized into three RWH potential areas: (a) low suitability, (b) medium suitability, and (c) high suitability. Nearly 40% of the watershed zone falls within medium and high suitability RWH potential areas. It is deduced that the integrated MCDA and geospatial techniques provide a valuable and formidable resource for the strategizing of RWH within the study zones. Full article

(This article belongs to the Section Hydrology)

► Show Figures

Figure 1

27 pages, 4363 KiB

Open AccessEditor’s ChoiceArticle

Validation of Water Quality Monitoring Algorithms for Sentinel-2 and Sentinel-3 in Mediterranean Inland Waters with In Situ Reflectance Data

by Xavier Sòria-Perpinyà, Eduardo Vicente, Patricia Urrego, Marcela Pereira-Sandoval, Carolina Tenjo, Antonio Ruíz-Verdú, Jesús Delegido, Juan Miguel Soria, Ramón Peña and José Moreno

Water 2021, 13(5), 686; https://doi.org/10.3390/w13050686 - 3 Mar 2021

Cited by 28 | Viewed by 4169

Abstract

Freshwater quality maintenance is essential for human use and ecological functions. To ensure this objective, governments establish programs for a continuous monitoring of the inland waters state. This could be possible with Sentinel-2 (S2) and Sentinel-3 (S3), two remote sensing satellites of the [...] Read more.

Freshwater quality maintenance is essential for human use and ecological functions. To ensure this objective, governments establish programs for a continuous monitoring of the inland waters state. This could be possible with Sentinel-2 (S2) and Sentinel-3 (S3), two remote sensing satellites of the European Space Agency, equipped with spectral optical sensors. To determine optimal water quality algorithms applicable to their spectral bands, 36 algorithms were tested for different key variables (chlorophyll a (Chl_a), colored dissolved organic matter (CDOM), colored dissolved organic matter (TSS), phycocyanin (PC) and Secchi disk depth (SDD)). A database of 296 water-leaving reflectance spectra were used, as well as concomitant water quality measurements of Mediterranean reservoirs and lakes of Spain. Two equal data sets were used for calibration and validation. The best algorithms were recalculated using all database and used the following band relations: SDD, R560/R700; CDOM, R665/R490; PC, R705/R665 for S2 and R620, R665, R709 and R779 for S3, using a semi-analytical algorithm; R700 for TSS < 20 mg/L and R783/R492 (S2) or R779/R510 (S3) for TSS > 20 mg/L; and for Chl_a, the maximum (R443; R492)/R560 for Chl_a < 5 mg/m³ and R700/R665 for Chl_a > 5 mg/m³. A preliminary test with a satellite image in a well-known reservoir showed results consistent with the expected ranges and spatial patterns of the variables. Full article

(This article belongs to the Special Issue Methods for Assessing Water Quality and Its Impacts on Ecological Status in Reservoirs)

► Show Figures

Figure 1

15 pages, 6161 KiB

Open AccessEditor’s ChoiceArticle

Minimum Residual Flows for Catchments in the Czech Republic

by Pavel Balvín, Adam Vizina, Magdalena Nesládková, Johanna Blöcher, Marcela Makovcová, Vojtěch Moravec and Martin Hanel

Water 2021, 13(5), 689; https://doi.org/10.3390/w13050689 - 3 Mar 2021

Cited by 5 | Viewed by 2253

Abstract

The determination of minimum residual flow (MRF) follows diverse methodology in Europe due to differing hydrological conditions, ecosystem requirements, water abstraction requirements, and legislation. Methodologies in individual countries are difficult to compare qualitatively. However, individual approaches can serve as examples for countries undergoing [...] Read more.

The determination of minimum residual flow (MRF) follows diverse methodology in Europe due to differing hydrological conditions, ecosystem requirements, water abstraction requirements, and legislation. Methodologies in individual countries are difficult to compare qualitatively. However, individual approaches can serve as examples for countries undergoing the process of developing new methodologies, either for legislative purposes or to improve environmental standards on watercourses. This is exactly the situation in the Czech Republic which, has been working on the Regulation of the Government of the Czech Republic for ten years, since the amendment to the Water Act in 2010, defines the methods and criteria for determining the MRF on watercourses. T.G. Masaryk Water Research Institute, p.r.i., was commissioned to develop a new methodology to serve as the basis for the wording of aforementioned regulation. The new methodological approach took into account modern trends concerning the preservation of ecological standards, and used standard hydrological characteristics for its calculations. The newly proposed approach is undergoing a complicated approval process as the authors seek to increase the MRF compared to the current approach. The new approach assumes an MRF setting between

Q_{97}

and

Q_{90}

. It defines four areas within the Czech Republic, by their hydrological and hydrogeological conditions, where the MRF is determined in different ways. This article describes the development of a new methodological approach, including the use the available Czech Hydrometeorological Institute data sets, the proposed regional division for MRF calculations, the determination the MRF below reservoirs, and the current state of the issue. Full article

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

► Show Figures

Figure 1

24 pages, 9316 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Numerical Simulations of the Flow Field of a Submerged Hydraulic Jump over Triangular Macroroughnesses

by Amir Ghaderi, Mehdi Dasineh, Francesco Aristodemo and Costanza Aricò

Water 2021, 13(5), 674; https://doi.org/10.3390/w13050674 - 2 Mar 2021

Cited by 22 | Viewed by 4419

Abstract

The submerged hydraulic jump is a sudden change from the supercritical to subcritical flow, specified by strong turbulence, air entrainment and energy loss. Despite recent studies, hydraulic jump characteristics in smooth and rough beds, the turbulence, the mean velocity and the flow patterns [...] Read more.

The submerged hydraulic jump is a sudden change from the supercritical to subcritical flow, specified by strong turbulence, air entrainment and energy loss. Despite recent studies, hydraulic jump characteristics in smooth and rough beds, the turbulence, the mean velocity and the flow patterns in the cavity region of a submerged hydraulic jump in the rough beds, especially in the case of triangular macroroughnesses, are not completely understood. The objective of this paper was to numerically investigate via the FLOW-3D model the effects of triangular macroroughnesses on the characteristics of submerged jump, including the longitudinal profile of streamlines, flow patterns in the cavity region, horizontal velocity profiles, streamwise velocity distribution, thickness of the inner layer, bed shear stress coefficient, Turbulent Kinetic Energy (TKE) and energy loss, in different macroroughness arrangements and various inlet Froude numbers (1.7 < Fr₁ < 9.3). To verify the accuracy and reliability of the present numerical simulations, literature experimental data were considered. Full article

(This article belongs to the Special Issue Hydraulic Dynamic Calculation and Simulation)

► Show Figures

Figure 1

11 pages, 2868 KiB

Open AccessEditor’s ChoiceArticle

The FLOod Probability Interpolation Tool (FLOPIT): A Simple Tool to Improve Spatial Flood Probability Quantification and Communication

by Mahkameh Zarekarizi, K. Joel Roop-Eckart, Sanjib Sharma and Klaus Keller

Water 2021, 13(5), 666; https://doi.org/10.3390/w13050666 - 1 Mar 2021

Cited by 2 | Viewed by 3166

Abstract

Understanding flood probabilities is essential to making sound decisions about flood-risk management. Many people rely on flood probability maps to inform decisions about purchasing flood insurance, buying or selling real-estate, flood-proofing a house, or managing floodplain development. Current flood probability maps typically use [...] Read more.

Understanding flood probabilities is essential to making sound decisions about flood-risk management. Many people rely on flood probability maps to inform decisions about purchasing flood insurance, buying or selling real-estate, flood-proofing a house, or managing floodplain development. Current flood probability maps typically use flood zones (for example the 1 in 100 or 1 in 500-year flood zones) to communicate flooding probabilities. However, this choice of communication format can miss important details and lead to biased risk assessments. Here we develop, test, and demonstrate the FLOod Probability Interpolation Tool (FLOPIT). FLOPIT interpolates flood probabilities between water surface elevation to produce continuous flood-probability maps. FLOPIT uses water surface elevation inundation maps for at least two return periods and creates Annual Exceedance Probability (AEP) as well as inundation maps for new return levels. Potential advantages of FLOPIT include being open-source, relatively easy to implement, capable of creating inundation maps from agencies other than FEMA, and applicable to locations where FEMA published flood inundation maps but not flood probability. Using publicly available data from the Federal Emergency Management Agency (FEMA) flood risk databases as well as state and national datasets, we produce continuous flood-probability maps at three example locations in the United States: Houston (TX), Muncy (PA), and Selinsgrove (PA). We find that the discrete flood zones generally communicate substantially lower flood probabilities than the continuous estimates. Full article

(This article belongs to the Section Hydrology)

► Show Figures

Figure 1

25 pages, 5952 KiB

Open AccessEditor’s ChoiceArticle

Sustainable Surface Water Storage Development Pathways and Acceptable Limits for River Basins

by Nishadi Eriyagama, Vladimir Smakhtin and Lakshika Udamulla

Water 2021, 13(5), 645; https://doi.org/10.3390/w13050645 - 28 Feb 2021

Cited by 2 | Viewed by 3742

Abstract

This paper addresses the questions of acceptable upper limits for storage development and how best to deploy storage capacity in the long-term planning of built surface water storage in river basins. Storage-yield curves are used to establish sustainable storage development pathways and limits [...] Read more.

This paper addresses the questions of acceptable upper limits for storage development and how best to deploy storage capacity in the long-term planning of built surface water storage in river basins. Storage-yield curves are used to establish sustainable storage development pathways and limits for a basin under a range of environmental flow release scenarios. Optimal storage distribution at a sub-basin level, which complies with an identified storage development pathway, can also be estimated. Two new indices are introduced—Water Supply Sustainability and Environmental Flow Sustainability—to help decide which pathways and management strategies are the most appropriate for a basin. Average pathways and conservative and maximum storage limits are illustrated for two example basins. Conservative and maximum withdrawal limits from storage are in the range of 45–50% and 60–65% of the mean annual runoff. The approach can compare the current level of basin storage with an identified pathway and indicate which parts of a basin are over- or under-exploited. A global storage–yield–reliability relationship may also be developed using statistics of annual basin precipitation to facilitate water resource planning in ungauged basins. Full article

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

► Show Figures

Figure 1

20 pages, 7470 KiB

Open AccessEditor’s ChoiceArticle

Groundwater-Potential Mapping Using a Self-Learning Bayesian Network Model: A Comparison among Metaheuristic Algorithms

by Sadegh Karimi-Rizvandi, Hamid Valipoori Goodarzi, Javad Hatami Afkoueieh, Il-Moon Chung, Ozgur Kisi, Sungwon Kim and Nguyen Thi Thuy Linh

Water 2021, 13(5), 658; https://doi.org/10.3390/w13050658 - 28 Feb 2021

Cited by 29 | Viewed by 3096

Abstract

Owing to the reduction of surface-water resources and frequent droughts, the exploitation of groundwater resources has faced critical challenges. For optimal management of these valuable resources, careful studies of groundwater potential status are essential. The main goal of this study was to determine [...] Read more.

Owing to the reduction of surface-water resources and frequent droughts, the exploitation of groundwater resources has faced critical challenges. For optimal management of these valuable resources, careful studies of groundwater potential status are essential. The main goal of this study was to determine the optimal network structure of a Bayesian network (BayesNet) machine-learning model using three metaheuristic optimization algorithms—a genetic algorithm (GA), a simulated annealing (SA) algorithm, and a Tabu search (TS) algorithm—to prepare groundwater-potential maps. The methodology was applied to the town of Baghmalek in the Khuzestan province of Iran. For modeling, the location of 187 springs in the study area and 13 parameters (altitude, slope angle, slope aspect, plan curvature, profile curvature, topography wetness index (TWI), distance to river, distance to fault, drainage density, rainfall, land use/cover, lithology, and soil) affecting the potential of groundwater were provided. In addition, the statistical method of certainty factor (CF) was utilized to determine the input weight of the hybrid models. The results of the OneR technique showed that the parameters of altitude, lithology, and drainage density were more important for the potential of groundwater compared to the other parameters. The results of groundwater-potential mapping (GPM) employing the receiver operating characteristic (ROC) area under the curve (AUC) showed an estimation accuracy of 0.830, 0.818, 0.810, and 0.792, for the BayesNet-GA, BayesNet-SA, BayesNet-TS, and BayesNet models, respectively. The BayesNet-GA model improved the GPM estimation accuracy of the BayesNet-SA (4.6% and 7.5%) and BayesNet-TS (21.8% and 17.5%) models with respect to the root mean square error (RMSE) and mean absolute error (MAE), respectively. Based on metric indices, the GA provides a higher capability than the SA and TS algorithms for optimizing the BayesNet model in determining the GPM. Full article

(This article belongs to the Section Hydrology)

► Show Figures

Figure 1

21 pages, 3670 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Distributed-Framework Basin Modeling System: Ⅲ. Hydraulic Modeling System

by Xiaoning Li, Chuanhai Wang, Gang Chen, Xing Fang, Pingnan Zhang and Wenjuan Hua

Water 2021, 13(5), 649; https://doi.org/10.3390/w13050649 - 28 Feb 2021

Cited by 5 | Viewed by 2145

Abstract

A distributed-framework basin modeling system (DFBMS) was developed to simulate the runoff generation and movement on a basin scale. This study is part of a series of papers on DFBMS that focuses on the hydraulic calculation methods in runoff concentration on underlying surfaces [...] Read more.

A distributed-framework basin modeling system (DFBMS) was developed to simulate the runoff generation and movement on a basin scale. This study is part of a series of papers on DFBMS that focuses on the hydraulic calculation methods in runoff concentration on underlying surfaces and flow movement in river networks and lakes. This paper introduces the distributed-framework river modeling system (DF-RMS) that is a professional modeling system for hydraulic modeling. The DF-RMS contains different hydrological feature units (HFUs) to simulate the runoff movement through a system of rivers, storage units, lakes, and hydraulic structures. The river network simulations were categorized into different types, including one-dimensional river branch, dendritic river network, loop river network, and intersecting river network. The DF-RMS was applied to the middle and downstream portions of the Huai River Plain in China using different HFUs for river networks and lakes. The simulation results showed great consistency with the observed data, which proves that DF-RMS is a reliable system to simulate the flow movement in river networks and lakes. Full article

(This article belongs to the Special Issue Modelling Hydrologic Response of Non-homogeneous Catchments)

► Show Figures

Figure 1

15 pages, 1032 KiB

Open AccessEditor’s ChoiceArticle

Modeling the Effect of Different Forest Types on Water Balance in the Three Gorges Reservoir Area in China, with CoupModel

by Zhi Yang, Fang Hou, Jinhua Cheng and Youyan Zhang

Water 2021, 13(5), 654; https://doi.org/10.3390/w13050654 - 28 Feb 2021

Cited by 2 | Viewed by 1945

Abstract

Precipitation, throughfall, stemflow, and soil water content were measured, whereas interception, transpiration, evaporation, deep percolation, and soil water recharge were estimated in three plots, including oak (Lithocarpus glaber), Chinese fir (Cunninghamia lanceolata) forestlands, and maize (Zea mays) [...] Read more.

Precipitation, throughfall, stemflow, and soil water content were measured, whereas interception, transpiration, evaporation, deep percolation, and soil water recharge were estimated in three plots, including oak (Lithocarpus glaber), Chinese fir (Cunninghamia lanceolata) forestlands, and maize (Zea mays) farmland in the Three Gorges Reservoir in China. A physical process-based model (CoupModel) was set up with climatic measurements as input and was calibrated with throughfall and vertical frequency domain reflectometry measurements from January 2018 to December 2019. Simulated values of soil moisture were fairly consistent with measured ones, with a determination coefficient (R²) of 0.73–0.91. Evapotranspiration was the main output of water balance, with a percentage of up to 61%, and such output was ranked as follows: oak forest (720 mm/y) > Chinese fir forest (700 mm/y) > maize farmland (600 mm/y). Afforestation influenced water balance, and water recharge was generally less significant in oak forestland than in Chinese fir forestland. Annual simulated deep percolation decreased by 60 mm for oak and 47 mm for Chinese fir compared with that for farmland (452 mm/y) and even more significantly in wet years. This decrease was mainly attributed to increased interception (122–159 mm/y) and transpiration (49–84 mm/y) after afforestation. Simulations indicated that vegetation species significantly influenced the magnitude of water balance components, calling for further attention to the selection of regrown tree species in the planning for afforestation projects, particularly for such projects that aim to improve the quantity of water infiltrating groundwater. Soil and water conservation measures should also be applied scientifically when converting farmland to forest in this area, particularly in the oak forest stand. Full article

► Show Figures

Figure 1

19 pages, 5870 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Climatic Controls on Mean and Extreme Streamflow Changes Across the Permafrost Region of Canada

by Rajesh R. Shrestha, Jennifer Pesklevits, Daqing Yang, Daniel L. Peters and Yonas B. Dibike

Water 2021, 13(5), 626; https://doi.org/10.3390/w13050626 - 27 Feb 2021

Cited by 7 | Viewed by 2754

Abstract

Climatic change is affecting streamflow regimes of the permafrost region, altering mean and extreme streamflow conditions. In this study, we analyzed historical trends in annual mean flow (Q_mean), minimum flow (Q_min), maximum flow (Q_max) and Q_max [...] Read more.

Climatic change is affecting streamflow regimes of the permafrost region, altering mean and extreme streamflow conditions. In this study, we analyzed historical trends in annual mean flow (Q_mean), minimum flow (Q_min), maximum flow (Q_max) and Q_max timing across 84 hydrometric stations in the permafrost region of Canada. Furthermore, we related streamflow trends with temperature and precipitation trends, and used a multiple linear regression (MLR) framework to evaluate climatic controls on streamflow components. The results revealed spatially varied trends across the region, with significantly increasing (at 10% level) Q_min for 43% of stations as the most prominent trend, and a relatively smaller number of stations with significant Q_mean, Q_max and Q_max timing trends. Temperatures over both the cold and warm seasons showed significant warming for >70% of basin areas upstream of the hydrometric stations, while precipitation exhibited increases for >15% of the basins. Comparisons of the 1976 to 2005 basin-averaged climatological means of streamflow variables with precipitation and temperature revealed a positive correlation between Q_mean and seasonal precipitation, and a negative correlation between Q_mean and seasonal temperature. The basin-averaged streamflow, precipitation and temperature trends showed weak correlations that included a positive correlation between Q_min and October to March precipitation trends, and negative correlations of Q_max timing with October to March and April to September temperature trends. The MLR-based variable importance analysis revealed the dominant controls of precipitation on Q_mean and Q_max, and temperature on Q_min. Overall, this study contributes towards an enhanced understanding of ongoing changes in streamflow regimes and their climatic controls across the Canadian permafrost region, which could be generalized for the broader pan-Arctic regions. Full article

(This article belongs to the Special Issue Hydrological Extremes in a Warming Climate: Nonstationarity, Uncertainties and Impacts)

► Show Figures

Figure 1

24 pages, 10585 KiB

Open AccessEditor’s ChoiceArticle

Supply and Demand Forecasting of Water Resource Coupling System in Upstream Yangtze River under Changing Environmental Conditions

by Sijing Lou, Li Mo, Jianzhong Zhou, Yongqiang Wang and Wenhao He

Water 2021, 13(5), 640; https://doi.org/10.3390/w13050640 - 27 Feb 2021

Cited by 5 | Viewed by 2468

Abstract

The upstream Yangtze River is located in the southwest of central China, where it flows through several ecosystems and densely populated regions that constitute a unique complex coupled system. To determine how the characteristics of supply and demand in a water-coupled system will [...] Read more.

The upstream Yangtze River is located in the southwest of central China, where it flows through several ecosystems and densely populated regions that constitute a unique complex coupled system. To determine how the characteristics of supply and demand in a water-coupled system will vary under the influence of climate change and human activity in this area in the next 85 years, the upper Yangtze basin was considered as the study area and was divided into seven sub-basins according to seven main control sections: Shigu, Panzhihua, Xiluodu, Xiangjiaba, Zhutuo, Cuntan, and Yichang; a method for water supply and demand research considering climate change was proposed. Based on simulated runoff in the study area under changing environmental conditions, this study analyzed the available water supply and constructed a long-term water demand forecasting model using the classified water use index method under macro regulation in the study area from 2016 to 2100. The results show that the total water demand in the upstream Yangtze River appears to first increase and then decrease in 2016–2100 and will reach its peak around 2028. The ecological pressure in the upstream Yangtze River increases gradually from upstream to downstream but will not reach the surface water utilization stress threshold (hereinafter referred to as stress threshold) for the next 85 years. The contradiction between monthly supply and demand is more prominent under ecological restrictions. Under the RCP4.5 scenario, water demand exceeds the stress threshold in each sub-basin across several months (mainly March, April, and May), and the water demand nearly reaches the damage threshold in May as the basin extends below the Zhutuo section. Full article

► Show Figures

Figure 1

20 pages, 6437 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Distributed-Framework Basin Modeling System: IV. Application in Taihu Basin

by Gang Chen, Chuanhai Wang, Xing Fang, Xiaoning Li, Pingnan Zhang and Wenjuan Hua

Water 2021, 13(5), 611; https://doi.org/10.3390/w13050611 - 26 Feb 2021

Cited by 6 | Viewed by 2204

Abstract

This paper presents the application of a distributed-framework basin modeling system (DFBMS) in Taihu Basin, China. The concepts of professional modeling systems and system integration/coupling have been summarized in the first three series papers. This study builds a hydrologic and hydrodynamic model for [...] Read more.

This paper presents the application of a distributed-framework basin modeling system (DFBMS) in Taihu Basin, China. The concepts of professional modeling systems and system integration/coupling have been summarized in the first three series papers. This study builds a hydrologic and hydrodynamic model for Taihu Basin, which is in the lowland plain areas with numerous polder areas. Digital underlying surface area data agree with the survey results from the water resource development and utilization. The runoff generated in each cell was calculated with the model based on the digital underlying surface data. According to the hydrological feature units (HFU) concept from the DFBMS, Taihu Basin was conceptualized into six different HFUs. The basic data of rainfall, evaporation, water surface elevation (WSE), discharge, tide level, and water resources for consumption and discharge in 2000 were used to calibrate the model. The simulated results of WSE and discharge matched the observed data well. The observed data of 1998, 1999, 2002, and 2003 were used to validate the model, with good agreement with the simulation results. Finally, the basic data from 2003 were used to simulate and evaluate the management scheme of water diversion from the Yangtze River to Taihu Lake. Overall, the DFBMS application in Taihu Basin showed good performance and proved that the proposed structure for DFBMS was effective and reliable. Full article

(This article belongs to the Special Issue Modelling Hydrologic Response of Non-homogeneous Catchments)

► Show Figures

Figure 1

22 pages, 5919 KiB

Open AccessEditor’s ChoiceArticle

Evaluating Vulnerability of Central Asian Water Resources under Uncertain Climate and Development Conditions: The Case of the Ili-Balkhash Basin

by Tesse de Boer, Homero Paltan, Troy Sternberg and Kevin Wheeler

Water 2021, 13(5), 615; https://doi.org/10.3390/w13050615 - 26 Feb 2021

Cited by 15 | Viewed by 8320

Abstract

The Ili-Balkhash basin (IBB) is considered a key region for agricultural development and international transport as part of China’s Belt and Road Initiative (BRI). The IBB is exemplary for the combined challenge of climate change and shifts in water supply and demand in [...] Read more.

The Ili-Balkhash basin (IBB) is considered a key region for agricultural development and international transport as part of China’s Belt and Road Initiative (BRI). The IBB is exemplary for the combined challenge of climate change and shifts in water supply and demand in transboundary Central Asian closed basins. To quantify future vulnerability of the IBB to these changes, we employ a scenario-neutral bottom-up approach with a coupled hydrological-water resource modelling set-up on the RiverWare modelling platform. This study focuses on reliability of environmental flows under historical hydro-climatic variability, future hydro-climatic change and upstream water demand development. The results suggest that the IBB is historically vulnerable to environmental shortages, and any increase in water consumption will increase frequency and intensity of shortages. Increases in precipitation and temperature improve reliability of flows downstream, along with water demand reductions upstream and downstream. Of the demand scenarios assessed, extensive water saving is most robust to climate change. However, the results emphasize the competition for water resources among up- and downstream users and between sectors in the lower Ili, underlining the importance of transboundary water management to mitigate cross-border impacts. The modelling tool and outcomes may aid decision-making under the uncertain future in the basin. Full article

(This article belongs to the Special Issue Feature Papers of Water, Agriculture and Aquaculture)

► Show Figures

Figure 1

16 pages, 3918 KiB

Open AccessEditor’s ChoiceArticle

Human Health Risk Assessment for Exposure to Potentially Toxic Elements in Polluted Rivers in the Ecuadorian Amazon

by Samantha Jiménez-Oyola, Kenny Escobar Segovia, María-Jesús García-Martínez, Marcelo Ortega, David Bolonio, Iker García-Garizabal and Bryan Salgado

Water 2021, 13(5), 613; https://doi.org/10.3390/w13050613 - 26 Feb 2021

Cited by 22 | Viewed by 3994

Abstract

Anthropogenic activities performed in the Ecuadorian Amazon have released potentially toxic elements (PTEs) into the rivers, causing severe environmental pollution and increasing the risk of exposure to the residents of the surrounding areas. This study aims to carry out a human health risk [...] Read more.

Anthropogenic activities performed in the Ecuadorian Amazon have released potentially toxic elements (PTEs) into the rivers, causing severe environmental pollution and increasing the risk of exposure to the residents of the surrounding areas. This study aims to carry out a human health risk assessment using deterministic and probabilistic methods to estimate the hazard index (HI) and total cancer risk (TCR) related to multi-pathway human exposure to PTEs in polluted rivers. Concentrations of Al, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in surface water and sediment samples from rivers on the Ecuadorian Amazon were considered to assess the potential adverse human health effects. As a result, deterministic and probabilistic estimations of cancer and non-cancer risk through exposure to surface waters and sediments were above the safety limit. A sensitivity analysis identified the concentration of PTEs and the exposure duration (ED) as the two most important variables for probabilistic health risk assessment. The highest risk for receptors was related to exposure to polluted sediments through incidental ingestion and dermal contact routes. According to the deterministic estimation, the human health risk through ingestion of water was above the threshold in specific locations. This study reveals the potential health risk to which the population is exposed. This information can be used as a baseline to develop public strategies to reduce anthropogenic pollution and exposure to PTEs in Ecuadorian Amazon rivers. Full article

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

► Show Figures

Graphical abstract

18 pages, 5592 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Climate Change Patterns of Wild Blueberry Fields in Downeast, Maine over the Past 40 Years

by Rafa Tasnim, Francis Drummond and Yong-Jiang Zhang

Water 2021, 13(5), 594; https://doi.org/10.3390/w13050594 - 25 Feb 2021

Cited by 19 | Viewed by 7824

Abstract

Maine, USA is the largest producer of wild blueberries (Vaccinium angustifolium Aiton), an important native North American fruit crop. Blueberry fields are mainly distributed in coastal glacial outwash plains which might not experience the same climate change patterns as the whole region. [...] Read more.

Maine, USA is the largest producer of wild blueberries (Vaccinium angustifolium Aiton), an important native North American fruit crop. Blueberry fields are mainly distributed in coastal glacial outwash plains which might not experience the same climate change patterns as the whole region. It is important to analyze the climate change patterns of wild blueberry fields and determine how they affect crop health so fields can be managed more efficiently under climate change. Trends in the maximum (T_max), minimum (T_min) and average (T_avg) temperatures, total precipitation (P_total), and potential evapotranspiration (PET) were evaluated for 26 wild blueberry fields in Downeast Maine during the growing season (May–September) over the past 40 years. The effects of these climate variables on the Maximum Enhanced Vegetation Index (EVI_max) were evaluated using Remote Sensing products and Geographic Information System (GIS) tools. We found differences in the increase in growing season T_max, T_min, T_avg, and P_total between those fields and the overall spatial average for the region (state of Maine), as well as among the blueberry fields. The maximum, minimum, and average temperatures of the studied 26 wild blueberry fields in Downeast, Maine showed higher rates of increase than those of the entire region during the last 40 years. Fields closer to the coast showed higher rates of warming compared with the fields more distant from the coast. Consequently, PET has been also increasing in wild blueberry fields, with those at higher elevations showing lower increasing rates. Optimum climatic conditions (threshold values) during the growing season were explored based on observed significant quadratic relationships between the climate variables (T_max and P_total), PET, and EVI_max for those fields. An optimum T_max and PET for EVI_max at 22.4 °C and 145 mm/month suggest potential negative effects of further warming and increasing PET on crop health and productivity. These climate change patterns and associated physiological relationships, as well as threshold values, could provide important information for the planning and development of optimal management techniques for wild blueberry fields experiencing climate change. Full article

(This article belongs to the Special Issue Impacts of Climate Change on Plant Water Use, Carbon Balance, Nutrient Economy, and Their Interactions)

► Show Figures

Figure 1

24 pages, 9555 KiB

Open AccessEditor’s ChoiceArticle

Mapping Groundwater Potential Zones Using a Knowledge-Driven Approach and GIS Analysis

by Qiande Zhu and Mohamed Abdelkareem

Water 2021, 13(5), 579; https://doi.org/10.3390/w13050579 - 24 Feb 2021

Cited by 54 | Viewed by 5076

Abstract

Despite the Sahara being one of the most arid regions on Earth, it has experienced rainfall conditions in the past and could hold plentiful groundwater resources. Thus, groundwater is one of the most precious water resources in this region, which suffers from water [...] Read more.

Despite the Sahara being one of the most arid regions on Earth, it has experienced rainfall conditions in the past and could hold plentiful groundwater resources. Thus, groundwater is one of the most precious water resources in this region, which suffers from water shortage due to the limited rainfall caused by climatic conditions. This article will assess the knowledge-driven techniques employed to develop a model to integrate the multicriteria derived from geologic, geomorphic, structural, seismic, hydrologic, and remotely sensed data. This model was tested on the defunct Kom Ombo area of Egypt’s Nile river basin in the eastern Sahara, which covers ~28,200 km², to reveal the promising areas of groundwater resources. To optimize the output map, we updated the model by adding the automated depression resulting from a fill-difference approach and seismic activity layers combined with other evidential maps, including slope, topography, geology, drainage density, lineament density, soil characteristics, rainfall, and morphometric characteristics, after assigning a weight for each using a Geographic Information System (GIS)-based knowledge-driven approach. The paleochannels and soil characteristics were visualized using Advanced Land Observing Satellite (ALOS)/Phased Array type L-band Synthetic Aperture Radar (PALSAR) data. Several hydromorphic characteristics, sinks/depressions, and sub-basin characteristics were extracted using Shuttle Radar Topography Mission (SRTM) data. The results revealed that the assessed groundwater potential zones (GPZs) can be arranged into five distinctive groups, depending on their probability for groundwater, namely very low (6.56%), low (22.62%), moderate (30.75%), high (29.71%), and very high (10.34%). The downstream areas and Wadi Garara have very high recharge and storage potential. Interferometry Synthetic Aperture Radar (InSAR) coherence change detection (CCD) derived from Sentinel-1 data revealed a consistency between areas with high InSAR CCD (low change) that received a plausible amount of surface water and those with very low InSAR CCD values close to 0 (high change). Landsat data validated the areas that received runoff and are of high potentiality. The twenty-nine groundwater well locations overlaid on the GPZs, to assess the predicted model, indicated that about 86.17% of the wells were matched with very good to moderate potential zones. Full article

► Show Figures

Figure 1

17 pages, 11528 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Transfer Learning with Convolutional Neural Networks for Rainfall Detection in Single Images

by Nicla Maria Notarangelo, Kohin Hirano, Raffaele Albano and Aurelia Sole

Water 2021, 13(5), 588; https://doi.org/10.3390/w13050588 - 24 Feb 2021

Cited by 12 | Viewed by 4000

Abstract

Near real-time rainfall monitoring at local scale is essential for urban flood risk mitigation. Previous research on precipitation visual effects supports the idea of vision-based rain sensors, but tends to be device-specific. We aimed to use different available photographing devices to develop a [...] Read more.

Near real-time rainfall monitoring at local scale is essential for urban flood risk mitigation. Previous research on precipitation visual effects supports the idea of vision-based rain sensors, but tends to be device-specific. We aimed to use different available photographing devices to develop a dense network of low-cost sensors. Using Transfer Learning with a Convolutional Neural Network, the rainfall detection was performed on single images taken in heterogeneous conditions by static or moving cameras without adjusted parameters. The chosen images encompass unconstrained verisimilar settings of the sources: Image2Weather dataset, dash-cams in the Tokyo Metropolitan area and experiments in the NIED Large-scale Rainfall Simulator. The model reached a test accuracy of 85.28% and an F1 score of 0.86. The applicability to real-world scenarios was proven with the experimentation with a pre-existing surveillance camera in Matera (Italy), obtaining an accuracy of 85.13% and an F1 score of 0.85. This model can be easily integrated into warning systems to automatically monitor the onset and end of rain-related events, exploiting pre-existing devices with a parsimonious use of economic and computational resources. The limitation is intrinsic to the outputs (detection without measurement). Future work concerns the development of a CNN based on the proposed methodology to quantify the precipitation intensity. Full article

(This article belongs to the Special Issue Observation-Driven Understanding, Prediction, and Management in Hydrological/Hydraulic Hazard and Risk Studies)

► Show Figures

Graphical abstract

18 pages, 1851 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Monitoring Groundwater Use as a Domestic Water Source by Urban Households: Analysis of Data from Lagos State, Nigeria and Sub-Saharan Africa with Implications for Policy and Practice

by Kerstin Danert and Adrian Healy

Water 2021, 13(4), 568; https://doi.org/10.3390/w13040568 - 23 Feb 2021

Cited by 13 | Viewed by 5829

Abstract

The fundamental importance of groundwater for urban drinking water supplies in sub-Saharan Africa is increasingly recognised. However, little is known about the trends in urban groundwater development by individual households and its role in securing safely-managed drinking water supplies. Anecdotal evidence indicates a [...] Read more.

The fundamental importance of groundwater for urban drinking water supplies in sub-Saharan Africa is increasingly recognised. However, little is known about the trends in urban groundwater development by individual households and its role in securing safely-managed drinking water supplies. Anecdotal evidence indicates a thriving self-supply movement to exploit groundwater in some urban sub-Saharan African settings, but empirical evidence, or analysis of the benefits and drawbacks, remains sparse. Through a detailed analysis of official datasets for Lagos State, Nigeria we examine the crucial role played by groundwater and, specifically, by household self-supply for domestic water provision. We then set this in the context of Nigeria and of sub-Saharan Africa. One of the novelties of this multi-scalar approach is that it provides a granular understanding from large-scale datasets. Our analysis confirms the importance of non-piped water supplies in meeting current and future drinking water demand by households in parts of sub-Saharan Africa and the role played, through self-supply, by groundwater. Our results demonstrate inconsistencies between datasets, and we make recommendations for the future. We argue that a key actor in the provision of drinking water supplies, the individual household, is largely overlooked by officially reported data, with implications for both policy and practice. Full article

(This article belongs to the Special Issue Present and Future of Drinking Water Supplies in Low-Income Regions)

► Show Figures

Figure 1

16 pages, 3191 KiB

Open AccessEditor’s ChoiceArticle

Deep Learning Framework with Time Series Analysis Methods for Runoff Prediction

by Zhenghe Li, Ling Kang, Liwei Zhou and Modi Zhu

Water 2021, 13(4), 575; https://doi.org/10.3390/w13040575 - 23 Feb 2021

Cited by 21 | Viewed by 4905

Abstract

Recent advances in deep learning, especially the long short-term memory (LSTM) networks, provide some useful insights on how to tackle time series prediction problems, not to mention the development of a time series model itself for prediction. Runoff forecasting is a time series [...] Read more.

Recent advances in deep learning, especially the long short-term memory (LSTM) networks, provide some useful insights on how to tackle time series prediction problems, not to mention the development of a time series model itself for prediction. Runoff forecasting is a time series prediction problem with a series of past runoff data (water level and discharge series data) as inputs and a fixed-length series of future runoff as output. Most previous work paid attention to the sufficiency of input data and the structural complexity of deep learning, while less effort has been put into the consideration of data quantity or the processing of original input data—such as time series decomposition, which can better capture the trend of runoff—or unleashing the effective potential of deep learning. Mutual information and seasonal trend decomposition are two useful time series methods in handling data quantity analysis and original data processing. Based on a former study, we proposed a deep learning model combined with time series analysis methods for daily runoff prediction in the middle Yangtze River and analyzed its feasibility and usability with frequently used counterpart models. Furthermore, this research also explored the data quality that affect the performance of the deep learning model. With the application of the time series method, we can effectively get some information about the data quality and data amount that we adopted in the deep learning model. The comparison experiment resulted in two different sites, implying that the proposed model improved the precision of runoff prediction and is much easier and more effective for practical application. In short, time series analysis methods can exert great potential of deep learning in daily runoff prediction and may unleash great potential of artificial intelligence in hydrology research. Full article

(This article belongs to the Special Issue Research of the Relationship between Climate Change and Runoff in Watershed)

► Show Figures

Figure 1

23 pages, 5453 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Assessing Multi-Hazard Vulnerability and Dynamic Coastal Flood Risk in the Mississippi Delta: The Global Delta Risk Index as a Social-Ecological Systems Approach

by Carl C. Anderson, Fabrice G. Renaud, Michael Hagenlocher and John W. Day

Water 2021, 13(4), 577; https://doi.org/10.3390/w13040577 - 23 Feb 2021

Cited by 13 | Viewed by 6254

Abstract

The tight coupling of the social-ecological system (SES) of the Mississippi Delta calls for balanced natural hazard vulnerability and risk assessments. Most existing assessments have approached these components in isolation. To address this, we apply the Global Delta Risk Index (GDRI) in the [...] Read more.

The tight coupling of the social-ecological system (SES) of the Mississippi Delta calls for balanced natural hazard vulnerability and risk assessments. Most existing assessments have approached these components in isolation. To address this, we apply the Global Delta Risk Index (GDRI) in the Mississippi Delta at high-resolution census tract level. We assess SES spatial patterns of drought, hurricane-force wind, and coastal flood vulnerability and integrate hazard and exposure data for the assessment of coastal flood risk. Moreover, we compare current coastal flood risk to future risk in 2025 based on the modelled effects of flood depth, exposure, and changes in ecosystem area in the context of ongoing efforts under the 2017 Louisiana Coastal Master Plan. Results show that the Master Plan will lead to decreases in risk scores by 2025, but the tracts that are currently the most vulnerable benefit less from risk reduction efforts. Along with our index output, we discuss the need for further advancements in SES methodology and the potential for catastrophic hazard events beyond the model parameters, such as extreme rainfall events and very strong hurricanes. Assessing SES risk components can lead to more targeted policy recommendations, demonstrated by the need for Master Plan projects to consider their unequal spatial effects on vulnerability and risk reduction. Full article

(This article belongs to the Special Issue Sustainable Management, Conservation and Restoration in Deltaic Ecosystems with Special Emphasis on the Mississippi Delta)

► Show Figures

Figure 1

19 pages, 11841 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Trend Analyses of Baseflow and BFI for Undisturbed Watersheds in Michigan—Constraints from Multi-Objective Optimization

by Benjamin Hagedorn and Christina Meadows

Water 2021, 13(4), 564; https://doi.org/10.3390/w13040564 - 23 Feb 2021

Cited by 6 | Viewed by 3522

Abstract

Documenting how ground- and surface water systems respond to climate change is crucial to understanding water resources, particularly in the U.S. Great Lakes region, where drastic temperature and precipitation changes are observed. This study presents baseflow and baseflow index (BFI) trend analyses for [...] Read more.

Documenting how ground- and surface water systems respond to climate change is crucial to understanding water resources, particularly in the U.S. Great Lakes region, where drastic temperature and precipitation changes are observed. This study presents baseflow and baseflow index (BFI) trend analyses for 10 undisturbed watersheds in Michigan using (1) multi-objective optimization (MOO) and (2) modified Mann–Kendall (MK) tests corrected for short-term autocorrelation (STA). Results indicate a variability in mean baseflow (0.09–8.70 m³/s) and BFI (67.9–89.7%) that complicates regional-scale extrapolations of groundwater recharge. Long-term (>60 years) MK trend tests indicate a significant control of total precipitation (P) and snow- to rainfall transitions on baseflow and BFI. In the Lower Peninsula Rifle River watershed, increasing P and a transition from snow- to rainfall has increased baseflow at a lower rate than streamflow; an overall pattern that may contribute to documented flood frequency increases. In the Upper Peninsula Ford River watershed, decreasing P and a transition from rain- to snowfall had no significant effects on baseflow and BFI. Our results highlight the value of an objectively constrained BFI parameter for shorter-term (<50 years) hydrologic trend analysis because of a lower STA susceptibility. Full article

(This article belongs to the Section Hydrology)

► Show Figures

Figure 1

20 pages, 2765 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

A Forecast-Skill-Based Dynamic Pre-Storm Level Control for Reservoir Flood-Control Operation

by Wenhua Wan, Xiaohui Lei, Jianshi Zhao, Mingna Wang, Soon-Thiam Khu and Chao Wang

Water 2021, 13(4), 556; https://doi.org/10.3390/w13040556 - 22 Feb 2021

Cited by 5 | Viewed by 2605

Abstract

The design and operation of reservoirs based on conventional flood-limited water levels (FLWL) implicitly adopts the assumption of hydrological stationarity. As such, historical-record-based FLWL may not be the best choice for flood-control operations due to the inherent non-stationarity of rainfall inputs. With maturing [...] Read more.

The design and operation of reservoirs based on conventional flood-limited water levels (FLWL) implicitly adopts the assumption of hydrological stationarity. As such, historical-record-based FLWL may not be the best choice for flood-control operations due to the inherent non-stationarity of rainfall inputs. With maturing flood forecasts, this study focuses on establishing linkage between FLWL and skill of forecast, thus developing a “dynamic pre-storm level” approach for reservoir flood-control operations. The approach utilizes forecast flood magnitude, forecast skill and exceedance probability of forecast error to determine the pre-storm reservoir storage for each flood event. The exceedance probability of forecast error for each incoming flood is used as the reservoir flood control standard instead of the probability of a static return interval flood. This approach is demonstrated in a hypothetical situation in the Three Gorges Reservoir in China. The results show that under zero-forecast-skill conditions, the proposed dynamic pre-storm level matches well with the Three Gorges Reservoir-designed FLWL; and, as the forecast accuracy/skill increase, the proposed approach can make better use of the increased forecast accuracy, thereby maximizing floodwater utilization and reservoir storage. In this way, coupling the new approach with FLWL allows for more efficient and economic day-to-day reservoir operations without adding any flood risk. This study validates the usefulness of dynamic water level control during flood season, considering the improvement of flood forecast accuracy. Full article

(This article belongs to the Special Issue Sustainable Development of Lakes and Reservoirs)

► Show Figures

Figure 1

18 pages, 2985 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Prediction of Combined Terrestrial Evapotranspiration Index (CTEI) over Large River Basin Based on Machine Learning Approaches

by Ahmed Elbeltagi, Nikul Kumari, Jaydeo K. Dharpure, Ali Mokhtar, Karam Alsafadi, Manish Kumar, Behrouz Mehdinejadiani, Hadi Ramezani Etedali, Youssef Brouziyne, Abu Reza Md. Towfiqul Islam and Alban Kuriqi

Water 2021, 13(4), 547; https://doi.org/10.3390/w13040547 - 20 Feb 2021

Cited by 61 | Viewed by 5188

Abstract

Drought is a fundamental physical feature of the climate pattern worldwide. Over the past few decades, a natural disaster has accelerated its occurrence, which has significantly impacted agricultural systems, economies, environments, water resources, and supplies. Therefore, it is essential to develop new techniques [...] Read more.

Drought is a fundamental physical feature of the climate pattern worldwide. Over the past few decades, a natural disaster has accelerated its occurrence, which has significantly impacted agricultural systems, economies, environments, water resources, and supplies. Therefore, it is essential to develop new techniques that enable comprehensive determination and observations of droughts over large areas with satisfactory spatial and temporal resolution. This study modeled a new drought index called the Combined Terrestrial Evapotranspiration Index (CTEI), developed in the Ganga river basin. For this, five Machine Learning (ML) techniques, derived from artificial intelligence theories, were applied: the Support Vector Machine (SVM) algorithm, decision trees, Matern 5/2 Gaussian process regression, boosted trees, and bagged trees. These techniques were driven by twelve different models generated from input combinations of satellite data and hydrometeorological parameters. The results indicated that the eighth model performed best and was superior among all the models, with the SVM algorithm resulting in an R² value of 0.82 and the lowest errors in terms of the Root Mean Squared Error (RMSE) (0.33) and Mean Absolute Error (MAE) (0.20), followed by the Matern 5/2 Gaussian model with an R² value of 0.75 and RMSE and MAE of 0.39 and 0.21 mm/day, respectively. Moreover, among all the five methods, the SVM and Matern 5/2 Gaussian methods were the best-performing ML algorithms in our study of CTEI predictions for the Ganga basin. Full article

(This article belongs to the Section Hydrology)

► Show Figures

Figure 1

17 pages, 6314 KiB

Open AccessEditor’s ChoiceArticle

Hydrochemical and Isotopic Characterization of the Waters of the Manglaralto River Basin (Ecuador) to Contribute to the Management of the Coastal Aquifer

by Paúl Carrión-Mero, F. Javier Montalván, Fernando Morante-Carballo, Javier Heredia, F. Javier Elorza, Joselyne Solórzano and Héctor Aguilera

Water 2021, 13(4), 537; https://doi.org/10.3390/w13040537 - 19 Feb 2021

Cited by 14 | Viewed by 4000

Abstract

Coastal aquifers are strategic and fundamental in the development of touristic areas. The coastal aquifer within the Manglaralto River Basin in Ecuador is essential, as it is the only source of water supply for a large part of the northern part of the [...] Read more.

Coastal aquifers are strategic and fundamental in the development of touristic areas. The coastal aquifer within the Manglaralto River Basin in Ecuador is essential, as it is the only source of water supply for a large part of the northern part of the Santa Elena province. It is a semi-arid region where high volumes of water are pumped from the aquifer, causing a significant drawdown of groundwater levels, thus affecting the water quality. This work aims to characterize the characteristics of groundwater in the coastal aquifer using hydrochemistry and stable isotopes to propose a hydrogeological conceptual model. The methodology for determining the chemical and isotopic characteristics of groundwater follows the following scheme: (i) studies of ionic concentrations using the Piper diagram, (ii) assessment of the origin of salinity through the Cl/Br ratio, the presence of seawater intrusion through the Hydrochemical Facies Evolution Diagram HFE-D, (iii) characterization of precipitation events using stable isotopes (¹⁸O and ²H), and, (iv) development of a hydrogeological conceptual model of the study area. The results indicate that in the basin there are mixing processes of the existing water in the aquifer with recharge water, direct cation exchange processes in the freshening process during recharge, and evaporation in the unsaturated zone. A conceptual model of the flow system in the basin is built, based on the mentioned processes. The main conclusions are: seawater intrusion is present in the areas of the wells located closest to the coast, urban activity through septic tanks is affecting the quality of the aquifer, and rainfall is highly relevant in the different hydrochemical and isotopic processes that operate in the basin. Full article

(This article belongs to the Special Issue Geochemistry of Groundwater)

► Show Figures

Figure 1

17 pages, 5472 KiB

Open AccessEditor’s ChoiceArticle

Operational Implementation of Satellite-Rain Gauge Data Merging for Hydrological Modeling

by Alejandra De Vera, Pablo Alfaro and Rafael Terra

Water 2021, 13(4), 533; https://doi.org/10.3390/w13040533 - 18 Feb 2021

Cited by 8 | Viewed by 3309

Abstract

Systems exposed to hydroclimatic variability, such as the integrated electric system in Uruguay, increasingly require real-time multiscale information to optimize management. Monitoring of the precipitation field is key to inform the future hydroelectric energy availability. We present an operational implementation of an algorithm [...] Read more.

Systems exposed to hydroclimatic variability, such as the integrated electric system in Uruguay, increasingly require real-time multiscale information to optimize management. Monitoring of the precipitation field is key to inform the future hydroelectric energy availability. We present an operational implementation of an algorithm that merges satellite precipitation estimates with rain gauge data, based on a 3-step technique: (i) Regression of station data on the satellite estimate using a Generalized Linear Model; (ii) Interpolation of the regression residuals at station locations to the entire grid using Ordinary Kriging and (iii) Application of a rain/no rain mask. The operational implementation follows five steps: (i) Data download and daily accumulation; (ii) Data quality control; (iii) Merging technique; (iv) Hydrological modeling and (v) Electricity-system simulation. The hydrological modeling is carried with the GR4J rainfall-runoff model applied to 17 sub-catchments of the G. Terra basin with routing up to the reservoir. The implementation became operational at the Electricity Market Administration (ADME) on June 2020. The performance of the merged precipitation estimate was evaluated through comparison with an independent, dense and uniformly distributed rain gauge network using several relevant statistics. Further validation is presented comparing the simulated inflow to the estimate derived from a reservoir mass budget. Results confirm that the estimation that incorporates the satellite information in addition to the surface observations has a higher performance than the one that only uses rain gauge data, both in the rainfall statistical evaluation and hydrological simulation. Full article

(This article belongs to the Special Issue Hydrometeorological Observation and Modeling)

► Show Figures

Figure 1

26 pages, 4937 KiB

Open AccessEditor’s ChoiceArticle

Comparison of Multicriteria Decision-Making Techniques for Groundwater Recharge Potential Zonation: Case Study of the Willochra Basin, South Australia

by Alaa Ahmed, Chathuri Ranasinghe-Arachchilage, Abdullah Alrajhi and Guna Hewa

Water 2021, 13(4), 525; https://doi.org/10.3390/w13040525 - 18 Feb 2021

Cited by 13 | Viewed by 3469

Abstract

In semi-arid regions, groundwater resources play a crucial role in all economic, environmental, and social processes. However, the occurrence, movement, and recharge of these hidden and valuable resources vary from place to place. Therefore, better management practices and mapping of groundwater recharge potential [...] Read more.

In semi-arid regions, groundwater resources play a crucial role in all economic, environmental, and social processes. However, the occurrence, movement, and recharge of these hidden and valuable resources vary from place to place. Therefore, better management practices and mapping of groundwater recharge potential zones are needed for the sustainable groundwater resources. For an example, groundwater resources in Willochra Basin are vitally important for drinking, irrigation, and stock use. This study shows the significance of the application of three decision-making approaches, including multi-influencing factor, analytical hierarchy process, and frequency ratio techniques in the identification of groundwater potential zones. A total of seven criteria, including lithology, slope, soil texture, land-use, rainfall, drainage density, and lineament density, were extracted from conventional and remote sensing data sources. The parameters and their assigned weights were integrated using Geographic Information System (GIS) software to generate recharge potential maps. The resultant maps were evaluated using the area under the curve method. The results showed that the southern regions of the Willochra Basin are more promising for groundwater recharge potential. The map produced using the frequency ratio model was the most efficient (84%), followed by the multi-influencing factor model (70%) and then the analytical hierarchy process technique (62%). The area under the curve method agreed when evaluated using published weights and rating values. Full article

(This article belongs to the Special Issue Water and Irrigation Management in Arid and Semiarid Zones)

► Show Figures

Figure 1

17 pages, 5608 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Distribution of Groundwater Arsenic in Uruguay Using Hybrid Machine Learning and Expert System Approaches

by Ruohan Wu, Elena M. Alvareda, David A. Polya, Gonzalo Blanco and Pablo Gamazo

Water 2021, 13(4), 527; https://doi.org/10.3390/w13040527 - 18 Feb 2021

Cited by 13 | Viewed by 4689

Abstract

Groundwater arsenic in Uruguay is an important environmental hazard, hence, predicting its distribution is important to inform stakeholders. Furthermore, occurrences in Uruguay are known to variably show dependence on depth and geology, arguably reflecting different processes controlling groundwater arsenic concentrations. Here, we present [...] Read more.

Groundwater arsenic in Uruguay is an important environmental hazard, hence, predicting its distribution is important to inform stakeholders. Furthermore, occurrences in Uruguay are known to variably show dependence on depth and geology, arguably reflecting different processes controlling groundwater arsenic concentrations. Here, we present the distribution of groundwater arsenic in Uruguay modelled by a variety of machine learning, basic expert systems, and hybrid approaches. A pure random forest approach, using 26 potential predictor variables, gave rise to a groundwater arsenic distribution model with a very high degree of accuracy (AUC = 0.92), which is consistent with known high groundwater arsenic hazard areas. These areas are mainly in southwest Uruguay, including the Paysandú, Río Negro, Soriano, Colonia, Flores, San José, Florida, Montevideo, and Canelones departments, where the Mercedes, Cuaternario Oeste, Raigón, and Cretácico main aquifers occur. A hybrid approach separating the country into sedimentary and crystalline aquifer domains resulted in slight material improvement in a high arsenic hazard distribution. However, a further hybrid approach separately modelling shallow (<50 m) and deep aquifers (>50 m) resulted in the identification of more high hazard areas in Flores, Durazno, and the northwest corner of Florida departments in shallow aquifers than the pure model. Both hybrid models considering depth (AUC = 0.95) and geology (AUC = 0.97) produced improved accuracy. Hybrid machine learning models with expert selection of important environmental parameters may sometimes be a better choice than pure machine learning models, particularly where there are incomplete datasets, but perhaps, counterintuitively, this is not always the case. Full article

► Show Figures

Figure 1

24 pages, 3455 KiB

Open AccessEditor’s ChoiceArticle

The Development of a Framework for the Integrated Assessment of SDG Trade-Offs in the Sundarban Biosphere Reserve

by Charlotte L. J. Marcinko, Robert J. Nicholls, Tim M. Daw, Sugata Hazra, Craig W. Hutton, Chris T. Hill, Derek Clarke, Andy Harfoot, Oindrila Basu, Isha Das, Sandip Giri, Sudipa Pal and Partho P. Mondal

Water 2021, 13(4), 528; https://doi.org/10.3390/w13040528 - 18 Feb 2021

Cited by 19 | Viewed by 7502

Abstract

The United Nations Sustainable Development Goals (SDGs) and their corresponding targets are significantly interconnected, with many interactions, synergies, and trade-offs between individual goals across multiple temporal and spatial scales. This paper proposes a framework for the Integrated Assessment Modelling (IAM) of a complex [...] Read more.

The United Nations Sustainable Development Goals (SDGs) and their corresponding targets are significantly interconnected, with many interactions, synergies, and trade-offs between individual goals across multiple temporal and spatial scales. This paper proposes a framework for the Integrated Assessment Modelling (IAM) of a complex deltaic socio-ecological system in order to analyze such SDG interactions. We focused on the Sundarban Biosphere Reserve (SBR), India, within the Ganges-Brahmaputra-Meghna Delta. It is densely populated with 4.4 million people (2011), high levels of poverty, and a strong dependence on rural livelihoods. It is adjacent to the growing megacity of Kolkata. The area also includes the Indian portion of the world’s largest mangrove forest––the Sundarbans––hosting the iconic Bengal Tiger. Like all deltaic systems, this area is subject to multiple drivers of environmental change operating across scales. The IAM framework is designed to investigate socio-environmental change under a range of explorative and/or normative scenarios and explore associated policy impacts, considering a broad range of subthematic SDG indicators. The following elements were explicitly considered: (1) agriculture; (2) aquaculture; (3) mangroves; (4) fisheries; and (5) multidimensional poverty. Key questions that can be addressed include the implications of changing monsoon patterns, trade-offs between agriculture and aquaculture, or the future of the Sundarbans’ mangroves under sea-level rise and different management strategies. The novel, high-resolution analysis of SDG interactions allowed by the IAM will provide stakeholders and policy makers the opportunity to prioritize and explore the SDG targets that are most relevant to the SBR and provide a foundation for further integrated analysis. Full article

(This article belongs to the Special Issue Sustainable Management, Conservation and Restoration in Deltaic Ecosystems with Special Emphasis on the Mississippi Delta)

► Show Figures

Figure 1

20 pages, 1895 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

The U.S.-Mexico Transboundary Aquifer Assessment Program as a Model for Transborder Groundwater Collaboration

by Elia M. Tapia-Villaseñor and Sharon B. Megdal

Water 2021, 13(4), 530; https://doi.org/10.3390/w13040530 - 18 Feb 2021

Cited by 18 | Viewed by 4367

Abstract

The assessment of transboundary aquifers is essential for the development of groundwater management strategies and the sustainable use of groundwater resources. The Transboundary Aquifer Assessment Program (TAAP) is a joint effort by the United States and Mexico to evaluate shared aquifers. This study [...] Read more.

The assessment of transboundary aquifers is essential for the development of groundwater management strategies and the sustainable use of groundwater resources. The Transboundary Aquifer Assessment Program (TAAP) is a joint effort by the United States and Mexico to evaluate shared aquifers. This study examines the TAAP Cooperative Framework as a guide for further transboundary groundwater collaboration. We compared lessons learned from six transboundary aquifers that currently have mechanisms for groundwater collaboration to identify common elements of collaboration. Though the TAAP Cooperative Framework governs an assessment-only program, the elements of collaboration included are consistent with the principles of other institutional agreements around the world. Importantly, all the analyzed agreements included a knowledge-improvement phase, which is the main objective of the TAAP Cooperative Framework. The present study finds evidence of successful outcomes within the TAAP Cooperative Framework consistent with available transboundary groundwater management agreements, demonstrating that this approach is suited to serve as a model for those wishing to engage in transborder aquifer assessments. Furthermore, the TAAP elements of collaboration can help to establish the meaningful and robust binational cooperation necessary for the development of U.S.-Mexico groundwater management agreements at the aquifer level. Full article

(This article belongs to the Special Issue Advances in Transboundary Aquifer Assessment)

► Show Figures

Figure 1

22 pages, 6752 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

A Planning Tool for Optimizing Investment to Reduce Drinking Water Risk to Multiple Water Treatment Plants in Open Catchments

by Chris Thompson, Morag Stewart, Nick Marsh, Viet Phung and Thomas Lynn

Water 2021, 13(4), 531; https://doi.org/10.3390/w13040531 - 18 Feb 2021

Viewed by 2416

Abstract

Supplying safe, secure, and reliable drinking water is a growing challenge particularly in regions where catchments have diverse land uses, rapidly growing populations, and are subject to increasing weather extremes such as in the subtropics. Catchments represent the first barrier in providing ecosystem [...] Read more.

Supplying safe, secure, and reliable drinking water is a growing challenge particularly in regions where catchments have diverse land uses, rapidly growing populations, and are subject to increasing weather extremes such as in the subtropics. Catchments represent the first barrier in providing ecosystem services for water quality protection and bulkwater suppliers are therefore investing in mitigation measures to reduce risk to drinking water quality for consumers. This paper presents an approach to combine data on erosion processes, pathogenic bacteria and protozoa from several sources, determine the highest risks from these hazards and identify an optimum portfolio of intervention activities that provide maximum risk reduction at water treatment plants (WTP) for a given budget using a simulated annealing optimizer. The approach is demonstrated in a catchment with six WTPs servicing small rural to urban populations. The catchment is predominantly used for agriculture. Results show that drinking water risk from protozoa can be reduced for most WTPs for moderate investment budget, while bacteria risk reduction requires significantly larger budget due to the greater number of significant source sites relative to protozoa. Total suspended sediment loads remain a very high risk to most of the WTPs due to the large extent of channel and gully erosion and landslides. A map of priority areas and associated suite of interventions are produced to guide on groundwork. Full article

(This article belongs to the Special Issue Impact of Land-Use Changes on Surface Hydrology and Water Quality)

► Show Figures

Figure 1

15 pages, 807 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Building the Treaty #3 Nibi Declaration Using an Anishinaabe Methodology of Ceremony, Language and Engagement

by Aimée Craft and Lucas King

Water 2021, 13(4), 532; https://doi.org/10.3390/w13040532 - 18 Feb 2021

Cited by 10 | Viewed by 4610

Abstract

Ratified in 2019, the Nibi Declaration of Treaty #3 voices the relationship with water (Nibi) and jurisdictional responsibility that all Anishinaabe citizens have within the Treaty #3 territory. It affirms the responsibilities and relationships that others living within the territory should have with [...] Read more.

Ratified in 2019, the Nibi Declaration of Treaty #3 voices the relationship with water (Nibi) and jurisdictional responsibility that all Anishinaabe citizens have within the Treaty #3 territory. It affirms the responsibilities and relationships that others living within the territory should have with the water and ensures that the spirit of Nibi is central to decision-making and water governance. This article details the process of developing The Declaration, in accordance with the Treaty #3 lawmaking process and, which was driven by women, in ceremony, with the help of Gitiizii m-inaanik, and with the input of The Nation as a whole. This process embodies nationhood, sovereignty, and Anishinaabe jurisdiction as it relates to the environment and water, in accordance with the Manito Aki Inakonigaawin (Mother Earth law). Every person has a relationship with water. The process of nurturing that relationship through the teachings exemplified in the implementation of The Declaration will provide clarity on the responsibilities and partnerships that must be developed to protect the water for future generations. Full article

(This article belongs to the Special Issue Sustainable Water Governance through Indigenous Research Approaches)

► Show Figures

Figure 1

18 pages, 21201 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Controls on Streamflow Densities in Semiarid Rocky Mountain Catchments

by Caroline Martin, Stephanie K. Kampf, John C. Hammond, Codie Wilson and Suzanne P. Anderson

Water 2021, 13(4), 521; https://doi.org/10.3390/w13040521 - 17 Feb 2021

Cited by 8 | Viewed by 2673

Abstract

Developing accurate stream maps requires both an improved understanding of the drivers of streamflow spatial patterns and field verification. This study examined streamflow locations in three semiarid catchments across an elevation gradient in the Colorado Front Range, USA. The locations of surface flow [...] Read more.

Developing accurate stream maps requires both an improved understanding of the drivers of streamflow spatial patterns and field verification. This study examined streamflow locations in three semiarid catchments across an elevation gradient in the Colorado Front Range, USA. The locations of surface flow throughout each channel network were mapped in the field and used to compute active drainage densities. Field surveys of active flow were compared to National Hydrography Dataset High Resolution (NHD HR) flowlines, digital topographic data, and geologic maps. The length of active flow declined with stream discharge in each of the catchments, with the greatest decline in the driest catchment. Of the tributaries that did not dry completely, 60% had stable flow heads and the remaining tributaries had flow heads that moved downstream with drying. The flow heads were initiated at mean contributing areas of 0.1 km² at the lowest elevation catchment and 0.5 km² at the highest elevation catchment, leading to active drainage densities that declined with elevation and snow persistence. The field mapped drainage densities were less than half the drainage densities that were represented using NHD HR. Geologic structures influenced the flow locations, with multiple flow heads initiated along faults and some tributaries following either fault lines or lithologic contacts. Full article

(This article belongs to the Special Issue Hydrology, Geomorphology, and Ecology of Intermittent Rivers and Streams)

► Show Figures

Figure 1

18 pages, 3662 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Inclusion of Hydraulic Controls in Rehabilitation Models of Drainage Networks to Control Floods

by Leonardo Bayas-Jiménez, F. Javier Martínez-Solano, Pedro L. Iglesias-Rey, Daniel Mora-Melia and Vicente S. Fuertes-Miquel

Water 2021, 13(4), 514; https://doi.org/10.3390/w13040514 - 17 Feb 2021

Cited by 3 | Viewed by 2856

Abstract

A problem for drainage systems managers is the increase in extreme rain events that are increasing in various parts of the world. Their occurrence produces hydraulic overload in the drainage system and consequently floods. Adapting the existing infrastructure to be able to receive [...] Read more.

A problem for drainage systems managers is the increase in extreme rain events that are increasing in various parts of the world. Their occurrence produces hydraulic overload in the drainage system and consequently floods. Adapting the existing infrastructure to be able to receive extreme rains without generating consequences for cities’ inhabitants has become a necessity. This research shows a new way to improve drainage systems with minimal investment costs, using for this purpose a novel methodology that considers the inclusion of hydraulic control elements in the network, the installation of storm tanks and the replacement of pipes. The presented methodology uses the Storm Water Management Model for the hydraulic analysis of the network and a modified Genetic Algorithm to optimize the network. In this algorithm, called the Pseudo-Genetic Algorithm, the coding of the chromosomes is integral and has been used in previous studies of hydraulic optimization. This work evaluates the cost of the required infrastructure and the damage caused by floods to find the optimal solution. The main conclusion of this study is that the inclusion of hydraulic controls can reduce the cost of network rehabilitation and decrease flood levels. Full article

(This article belongs to the Special Issue Urban Hydraulic Engineering Simulation and Calculation)

► Show Figures

Figure 1

15 pages, 1598 KiB

Open AccessEditor’s ChoiceArticle

An Initial Framework for Understanding the Resilience of Aquifers to Groundwater Pumping

by África de la Hera-Portillo, Julio López-Gutiérrez, Beatriz Mayor, Elena López-Gunn, Hans Jørgen Henriksen, Ryle Nørskov Gejl, Pedro Zorrilla-Miras and Pedro Martínez-Santos

Water 2021, 13(4), 519; https://doi.org/10.3390/w13040519 - 17 Feb 2021

Cited by 5 | Viewed by 2549

Abstract

Groundwater stored in aquifers experiences a wide variety of natural, induced and/or anthropogenic disturbances. Among them, groundwater extraction is the main disturbance that affects most of the aquifers in the world. Aquifer’s resilience, understood as the potential of the aquifer to sustain disturbances [...] Read more.

Groundwater stored in aquifers experiences a wide variety of natural, induced and/or anthropogenic disturbances. Among them, groundwater extraction is the main disturbance that affects most of the aquifers in the world. Aquifer’s resilience, understood as the potential of the aquifer to sustain disturbances on the long term and to guarantee essential qualities and functions, provides a key tool when assessing sustainable groundwater management alternatives. The aim of this work is to illustrate an aquifer resilience framework that can support groundwater sustainable management. A theoretical framework is based on the identification of the key variables that parameterize the quantitative and qualitative responses of the groundwater flow system to pumping. An example from the literature based in Denmark is provided as an illustration of the proposed framework. The results show that long-term high quality data are essential to make a step further in aquifers dynamic responses. The quantitative understanding of the aquifer’s behavior before, during and after groundwater extraction provides a valuable source of information in order to identify thresholds of change (tipping points, transitions or regime shifts) which could permit pro-active groundwater management decisions. Moreover, a deeper understanding on the aquifer’s dynamics provides useful information in order to avert threats that may put the sustainability of the system at risk. Full article

(This article belongs to the Special Issue Water Management to Protect Aquatic Ecosystems Function and Health in the Face of Climate Change)

► Show Figures

Figure 1

17 pages, 2733 KiB

Open AccessEditor’s ChoiceArticle

Assessing the Potential of Agricultural Reservoirs as the Source of Environmental Flow

by Young-Jun Jo, Jung-Hun Song, Younggu Her, Giorgio Provolo, Jina Beom, Minhyuk Jeung, Young-Joo Kim, Seung-Hwan Yoo and Kwang-Sik Yoon

Water 2021, 13(4), 508; https://doi.org/10.3390/w13040508 - 15 Feb 2021

Cited by 6 | Viewed by 2774

Abstract

Excessive nutrient loadings from drainage areas and resulting water quality degradation in rivers are the major environmental issues around the world. The water quality further deteriorates for the large seasonal variation of precipitation and water flow. Environmental decision makers have been exploring affordable [...] Read more.

Excessive nutrient loadings from drainage areas and resulting water quality degradation in rivers are the major environmental issues around the world. The water quality further deteriorates for the large seasonal variation of precipitation and water flow. Environmental decision makers have been exploring affordable and effective ways of securing environmental flow (EF) to improve the water quality, especially in dry seasons, and agricultural reservoirs have attracted the attention of policymakers as an alternative source of EF. This study proposed an analysis framework for assessing the EF supply potential of agricultural reservoirs as alternative sources of EF. A reservoir water balance model was prepared to mathematically represent the reservoir water balance and quantify temporal variations of the amount of water available for the EF supply. The simulation model was designed to explicitly consider inflow from the upstream drainage areas, irrigation water requirement, and hydrological processes happening in the reservoirs. The proposed framework was applied to four agricultural reservoirs located in South Korea to evaluate its efficiency. Results showed that the additional storage capacity added by the dam reinforcement enabled the study reservoirs to satisfy both needs, EF and irrigation water supply. The surplus capacity turned out to be enough to satisfy various EF supply scenarios at the annual time scale. However, the current operation plans do not consider the seasonal variations of reservoir hydrology and thus cannot supply EF without violating the original operational goal, irrigation water, especially in dry months. The results demonstrate that it is necessary to consider the temporal variations of EF when developing reservoir operation rules and plans to secure EF. This study also highlights the unconventional roles of agricultural reservoirs as resources for improved environmental quality. The methods presented in this study are expected to be a useful tool for the assessment of agricultural reservoirs’ EF supply potential. Full article

(This article belongs to the Special Issue Water Management for Agricultural, Environmental and Urban Uses)

► Show Figures

Figure 1

20 pages, 8470 KiB

Open AccessEditor’s ChoiceArticle

Analysis of Pore Water Pressure and Piping of Hydraulic Well

by Jinman Kim, Heuisoo Han and Yoonhwa Jin

Water 2021, 13(4), 502; https://doi.org/10.3390/w13040502 - 15 Feb 2021

Cited by 1 | Viewed by 2055

Abstract

This paper shows the results of a field appliance study of the hydraulic well method to prevent embankment piping, which is proposed by the Japanese Matsuyama River National Highway Office. The large-scale embankment experiment and seepage analysis were conducted to examine the hydraulic [...] Read more.

This paper shows the results of a field appliance study of the hydraulic well method to prevent embankment piping, which is proposed by the Japanese Matsuyama River National Highway Office. The large-scale embankment experiment and seepage analysis were conducted to examine the hydraulic well. The experimental procedure is focused on the pore water pressure. The water levels of the hydraulic well were compared with pore water pressure data, which were used to look over the seepage variations. Two different types of large-scale experiments were conducted according to the installation points of hydraulic wells. The seepage velocity results by the experiment were almost similar to those of the analyses. Further, the pore water pressure oriented from the water level variations in the hydraulic well showed similar patterns between the experiment and numerical analysis; however, deeper from the surface, the larger pore water pressure of the numerical analysis was calculated compared to the experimental values. In addition, the piping effect according to the water level and location of the hydraulic well was quantitatively examined for an embankment having a piping guide part. As a result of applying the hydraulic well to the point where piping occurred, the hydraulic well with a 1.0 m water level reduced the seepage velocity by up to 86%. This is because the difference in the water level between the riverside and the protected side is reduced, and it resulted in reducing the seepage pressure. As a result of the theoretical and numerical hydraulic gradient analysis according to the change in the water level of the hydraulic well, the hydraulic gradient decreased linearly according to the water level of the hydraulic well. From the results according to the location of the hydraulic well, installation of it at the point where piping occurred was found to be the most effective. A hydraulic well is a good device for preventing the piping of an embankment if it is installed at the piping point and the proper water level of the hydraulic well is applied. Full article

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

► Show Figures

Figure 1

22 pages, 5223 KiB

Open AccessEditor’s ChoiceArticle

Reconstructing Spatiotemporal Dynamics in Hydrological State Along Intermittent Rivers

by Michael Eastman, Simon Parry, Catherine Sefton, Juhyun Park and Judy England

Water 2021, 13(4), 493; https://doi.org/10.3390/w13040493 - 14 Feb 2021

Cited by 6 | Viewed by 3184

Abstract

Despite the impact of flow cessation on aquatic ecology, the hydrology of intermittent rivers has been largely overlooked. This has resulted in a lack of monitoring projects, and consequently, datasets spanning a period of sufficient duration to characterise both hydrological extremes. This report [...] Read more.

Despite the impact of flow cessation on aquatic ecology, the hydrology of intermittent rivers has been largely overlooked. This has resulted in a lack of monitoring projects, and consequently, datasets spanning a period of sufficient duration to characterise both hydrological extremes. This report documents an investigation into the potential for statistical modelling to simulate the spatiotemporal dynamics of flowing, ponded and dry hydrological states in an internationally rare hydrological state dataset. The models presented predict unrecorded hydrological state data with performance metrics exceeding 95%, providing insights into the relationship between ponding prevalence and the performance of statistical simulation of this ecologically important intermediate state between drying and flowing conditions. This work demonstrates the potential for hydrological intermittence to be simulated in areas where hydrological state data are often sparse, providing opportunities for quality control and data infilling. This further understanding of the processes driving intermittence will inform future water resource assessments and the influence of climate change on hydrological intermittence. Full article

(This article belongs to the Special Issue Hydrology, Geomorphology, and Ecology of Intermittent Rivers and Streams)

► Show Figures

Figure 1

18 pages, 4243 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Influence of Intensive Agriculture on Benthic Macroinvertebrate Assemblages and Water Quality in the Aconcagua River Basin (Central Chile)

by Pablo Fierro, Claudio Valdovinos, Carlos Lara and Gonzalo S. Saldías

Water 2021, 13(4), 492; https://doi.org/10.3390/w13040492 - 14 Feb 2021

Cited by 14 | Viewed by 3643

Abstract

This study assessed natural variation in the macroinvertebrate assemblages (MIB) and water quality in one of the main basins with the largest agricultural activities in Chile (Aconcagua River Basin). We sampled throughout the annual cycle; nine sampling sites were established along the basin, [...] Read more.

This study assessed natural variation in the macroinvertebrate assemblages (MIB) and water quality in one of the main basins with the largest agricultural activities in Chile (Aconcagua River Basin). We sampled throughout the annual cycle; nine sampling sites were established along the basin, classifying according to agricultural area coverage as least-disturbed, intermediate, and most-disturbed. We collected 56 macroinvertebrate taxa throughout the entire study area. Multivariate analysis shows significant differences among the three disturbance categories in different seasons, both water quality variables and the MIB structure. Distance-based linear model (DistLM) analysis for all seasons explained more than 95.9% of the macroinvertebrate assemblages, being significantly explained by chemical oxygen demand, pH, total coliforms, nitrites, elevation, and water temperature. ANOVA test revealed significant differences in the proportion of noninsect individuals, macroinvertebrates density, and the number of taxa among the three disturbance categories (p < 0.05). In general, water temperature, conductivity, chemical oxygen demand, ammonium, nitrites, and nitrates increased their values downstream in the basin. Our results indicate that the elevation gradient and increment in agricultural land use in the basin had a strong influence on water quality and MIB. A better understanding of these ecosystems could help conservation and integrated watershed management. Full article

(This article belongs to the Special Issue Impact of Land-Use Changes on Surface Hydrology and Water Quality)

► Show Figures

Figure 1

19 pages, 7032 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Seasonal Variations of Dissolved Organic Matter by Fluorescent Analysis in a Typical River Catchment in Northern China

by Zenglei Han, Min Xiao, Fujun Yue, Yuanbi Yi and K. M. G. Mostofa

Water 2021, 13(4), 494; https://doi.org/10.3390/w13040494 - 14 Feb 2021

Cited by 16 | Viewed by 2786

Abstract

Fluorescence (excitation-emission matrices, EEMs) spectroscopy coupled with PARAFAC (parallel factor) modelling and UV-Vis (ultraviolet visible) spectra were used to ascertain the sources, distribution and biogeochemical transformation of dissolved organic matter (DOM) in the Duliujian River catchment. Dissolved organic carbon (DOC), chromophoric dissolved organic [...] Read more.

Fluorescence (excitation-emission matrices, EEMs) spectroscopy coupled with PARAFAC (parallel factor) modelling and UV-Vis (ultraviolet visible) spectra were used to ascertain the sources, distribution and biogeochemical transformation of dissolved organic matter (DOM) in the Duliujian River catchment. Dissolved organic carbon (DOC), chromophoric dissolved organic matter (a₃₃₅) (CDOM), and hydrophobic components (a₂₆₀) were higher in summer than in other seasons with 53.3 m⁻¹, while aromaticity (SUVA₂₅₄) was higher in spring. Four fluorescent components, namely terrestrial humic acid (HA)-like (A/C), terrestrial fulvic acid (FA)-like (A/M), autochthonous fulvic acid (FA)-like (A/M), and protein-like substances (Tuv/T), were identified using EEM-PARAFAC modelling in this river catchment. The results demonstrated that terrestrial HA-like substances enhance its contents in summer ARE compared with BRE, whilst terrestrial FA-like substances were newly input in summer ARE, which was entirely absent upstream and downstream, suggesting that rain events could significantly input the terrestrial soil-derived DOM in the ambient downward catchments. Autochthonous FA-like substances in summer BRE could derive from phytoplankton in the downstream waters. The results also showed that DOM from wetland exhibited lower fluorescent intensity of humic-like peak A/C and fulvic-like peak A/M, molecular weight (S_R) and humification index (HIX) during the low-flow season. Built-up land, cropland, and unused land displayed higher a₃₃₅ (CDOM). A higher proportion of forest and industrial land in the SCs showed higher SUVA₂₅₄ values. Humic-like moiety, molecular weight and aromaticity were more responsive to land use during stormflow in summer. Rainfall could increase the export of soil DOM from cropland and unused land, which influences the spatial variation of HIX. The results in this study highlighted that terrestrial DOM has a significant influence on the biogeochemical alterations of DOM compositions and thus water quality in the downward watershed catchments, which might significantly vary according to the land-use types and their alterations by human activities. Full article

(This article belongs to the Section Hydrology)

► Show Figures

Figure 1

26 pages, 5654 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Modelling of the Discharge Response to Climate Change under RCP8.5 Scenario in the Alata River Basin (Mersin, SE Turkey)

by Ümit Yıldırım, Cüneyt Güler, Barış Önol, Michael Rode and Seifeddine Jomaa

Water 2021, 13(4), 483; https://doi.org/10.3390/w13040483 - 13 Feb 2021

Cited by 12 | Viewed by 4350

Abstract

This study investigates the impacts of climate change on the hydrological response of a Mediterranean mesoscale catchment using a hydrological model. The effect of climate change on the discharge of the Alata River Basin in Mersin province (Turkey) was assessed under the worst-case [...] Read more.

This study investigates the impacts of climate change on the hydrological response of a Mediterranean mesoscale catchment using a hydrological model. The effect of climate change on the discharge of the Alata River Basin in Mersin province (Turkey) was assessed under the worst-case climate change scenario (i.e., RCP8.5), using the semi-distributed, process-based hydrological model Hydrological Predictions for the Environment (HYPE). First, the model was evaluated temporally and spatially and has been shown to reproduce the measured discharge consistently. Second, the discharge was predicted under climate projections in three distinct future periods (i.e., 2021–2040, 2046–2065 and 2081–2100, reflecting the beginning, middle and end of the century, respectively). Climate change projections showed that the annual mean temperature in the Alata River Basin rises for the beginning, middle and end of the century, with about 1.35, 2.13 and 4.11 °C, respectively. Besides, the highest discharge timing seems to occur one month earlier (February instead of March) compared to the baseline period (2000–2011) in the beginning and middle of the century. The results show a decrease in precipitation and an increase in temperature in all future projections, resulting in more snowmelt and higher discharge generation in the beginning and middle of the century scenarios. However, at the end of the century, the discharge significantly decreased due to increased evapotranspiration and reduced snow depth in the upstream area. The findings of this study can help develop efficient climate change adaptation options in the Levant’s coastal areas. Full article

(This article belongs to the Special Issue Research of the Relationship between Climate Change and Runoff in Watershed)

► Show Figures

Graphical abstract

24 pages, 13996 KiB

Open AccessEditor’s ChoiceArticle

Rainfall-Induced Shallow Landslide Detachment, Transit and Runout Susceptibility Mapping by Integrating Machine Learning Techniques and GIS-Based Approaches

by Mariano Di Napoli, Diego Di Martire, Giuseppe Bausilio, Domenico Calcaterra, Pierluigi Confuorto, Marco Firpo, Giacomo Pepe and Andrea Cevasco

Water 2021, 13(4), 488; https://doi.org/10.3390/w13040488 - 13 Feb 2021

Cited by 40 | Viewed by 5182

Abstract

Rainfall-induced shallow landslides represent a serious threat in hilly and mountain areas around the world. The mountainous landscape of the Cinque Terre (eastern Liguria, Italy) is increasingly popular for both Italian and foreign tourists, most of which visit this outstanding terraced coastal [...] Read more.

Rainfall-induced shallow landslides represent a serious threat in hilly and mountain areas around the world. The mountainous landscape of the Cinque Terre (eastern Liguria, Italy) is increasingly popular for both Italian and foreign tourists, most of which visit this outstanding terraced coastal landscape to enjoy a beach holiday and to practice hiking. However, this area is characterized by a high level of landslide hazard due to intense rainfalls that periodically affect its rugged and steep territory. One of the most severe events occurred on 25 October 2011, causing several fatalities and damage for millions of euros. To adequately address the issues related to shallow landslide risk, it is essential to develop landslide susceptibility models as reliable as possible. Regrettably, most of the current land-use and urban planning approaches only consider the susceptibility to landslide detachment, neglecting transit and runout processes. In this study, the adoption of a combined approach allowed to estimate shallow landslide susceptibility to both detachment and potential runout. At first, landslide triggering susceptibility was assessed using Machine Learning techniques and applying the Ensemble approach. Nine predisposing factors were chosen, while a database of about 300 rainfall-induced shallow landslides was used as input. Then, a Geographical Information System (GIS)-based procedure was applied to estimate the potential landslide runout using the “reach angle” method. Information from such analyses was combined to obtain a susceptibility map describing detachment, transit, and runout. The obtained susceptibility map will be helpful for land planning, as well as for decision makers and stakeholders, to predict areas where rainfall-induced shallow landslides are likely to occur in the future and to identify areas where hazard mitigation measures are needed. Full article

(This article belongs to the Special Issue Rainfall-Induced Shallow Landslides Modeling and Warning)

► Show Figures

Figure 1

15 pages, 831 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Utilization of Biomass Derived from Cyanobacteria-Based Agro-Industrial Wastewater Treatment and Raisin Residue Extract for Bioethanol Production

by Olga N. Tsolcha, Vasiliki Patrinou, Christina N. Economou, Marianna Dourou, George Aggelis and Athanasia G. Tekerlekopoulou

Water 2021, 13(4), 486; https://doi.org/10.3390/w13040486 - 13 Feb 2021

Cited by 32 | Viewed by 3284

Abstract

Biofuels produced from photosynthetic microorganisms such as microalgae and cyanobacteria could potentially replace fossil fuels as they offer several advantages over fuels produced from lignocellulosic biomass. In this study, energy production potential in the form of bioethanol was examined using different biomasses derived [...] Read more.

Biofuels produced from photosynthetic microorganisms such as microalgae and cyanobacteria could potentially replace fossil fuels as they offer several advantages over fuels produced from lignocellulosic biomass. In this study, energy production potential in the form of bioethanol was examined using different biomasses derived from the growth of a cyanobacteria-based microbial consortium on a chemical medium and on agro-industrial wastewaters (i.e., dairy wastewater, winery wastewater and mixed winery–raisin effluent) supplemented with a raisin residue extract. The possibility of recovering fermentable sugars from a microbial biomass dominated by the filamentous cyanobacterium Leptolynbgya sp. was demonstrated. Of the different acid hydrolysis conditions tested, the best results were obtained with sulfuric acid 2.5 N for 120 min using dried biomass from dairy wastewater and mixed winery–raisin wastewaters. After optimizing sugar release from the microbial biomass by applying acid hydrolysis, alcoholic fermentation was performed using the yeast Saccharomyces cerevisiae. Raisin residue extract was added to the treated biomass broth in all experiments to enhance ethanol production. Results showed that up to 85.9% of the theoretical ethanol yield was achieved, indicating the potential use of cyanobacteria-based biomass in combination with a raisin residue extract as feedstock for bioethanol production. Full article

(This article belongs to the Special Issue Application of Circular Economy Principles in Water and Wastewater Utilities)

► Show Figures

Figure 1

23 pages, 3439 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Use of Fixed and Variable Speed Pumps in Water Distribution Networks with Different Control Strategies

by Christian X. Briceño-León, Pedro L. Iglesias-Rey, F. Javier Martinez-Solano, Daniel Mora-Melia and Vicente S. Fuertes-Miquel

Water 2021, 13(4), 479; https://doi.org/10.3390/w13040479 - 12 Feb 2021

Cited by 13 | Viewed by 4275

Abstract

The control system’s point is to bring the pumping curve close to the set-point curve. That concept is essential for proper design of a pumping station. An adequate design is focused not only on selecting the total number of pumps and the type [...] Read more.

The control system’s point is to bring the pumping curve close to the set-point curve. That concept is essential for proper design of a pumping station. An adequate design is focused not only on selecting the total number of pumps and the type of control to use (flow or pressure), but it also is important to determine the optimal number of fixed speed pumps (FSPs) and variable speed pumps (VSPs) for each flow rate. This work discusses the most common methods and procedures for control systems on a design of pumping stations with a proposed methodology. This methodology consists of expressing the characteristics of the pumping curve and the set-point curve in a dimensionless form so that the methodology is standardized for any pump model and set-point curve. These formulations allow us to discuss how the characteristic of a pump and the set-point curve of the network influence the optimal number of FSPs and VSPs in energy terms. In general, the objective of this work is to determine the most suitable total number of pumps in a pumping station design and to determine the optimal pumping configuration in every flow rate, thus the consumed energy would be the minimum. Additionally, this methodology develops an expression to estimate the performance of a frequency inverter when a VSP operates at different rotational speeds. This work will be applied to different study cases, and the obtained results allow us to question several usual procedures for pumping control system. In general, it can be concluded that the number of pumps of a pumping system cannot be inferred in a simple form without a deep analysis of a control system. Full article

(This article belongs to the Special Issue Urban Hydraulic Engineering Simulation and Calculation)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Editor’s Choice Articles

Article

Further Information

Guidelines

MDPI Initiatives

Follow MDPI