Water

9 pages, 697 KiB

Open AccessEditor’s ChoiceArticle

Crossroads of Continents and Modern Boundaries: An Introduction to Inuit and Chukchi Experiences in the Bering Strait, Beaufort Sea, and Baffin Bay

by Henry P. Huntington, Richard Binder Sr., Robert Comeau, Lene Kielsen Holm, Vera Metcalf, Toku Oshima, Carla SimsKayotuk and Eduard Zdor

Water 2020, 12(6), 1808; https://doi.org/10.3390/w12061808 - 24 Jun 2020

Cited by 6 | Viewed by 5970

Abstract

The homeland of Inuit extends from Asia and the Bering Sea to Greenland and the Atlantic Ocean. Inuit and their Chukchi neighbors have always been highly mobile, but the imposition of three international borders in the region constrained travel, trade, hunting, and resource [...] Read more.

The homeland of Inuit extends from Asia and the Bering Sea to Greenland and the Atlantic Ocean. Inuit and their Chukchi neighbors have always been highly mobile, but the imposition of three international borders in the region constrained travel, trade, hunting, and resource stewardship among neighboring groups. Colonization, assimilation, and enforcement of national laws further separated those even from the same family. In recent decades, Inuit and Chukchi have re-established many ties across those boundaries, making it easier to travel and trade with one another and to create new institutions of environmental management. To introduce Indigenous perspectives into the discussion of transboundary maritime water connections in the Arctic, this paper presents personal descriptions of what those connections mean to people who live and work along and across each of the national frontiers within the region: Russia–U.S., U.S.–Canada, and Canada–Greenland. Some of these connections have been made in cooperation with national governments, some in the absence of government activity, and some despite opposition from national governments. In all cases, the shared culture of the region has provided a common foundation for a shared vision and commitment to cooperation and the resumption of Indigenous self-determination within their homelands. Full article

(This article belongs to the Special Issue Transboundary Water Governance: New Sights and Developments)

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22 pages, 8274 KiB

Open AccessEditor’s ChoiceArticle

Applied Strategy to Characterize the Energy Improvement Using PATs in a Water Supply System

by Luis E. Camilo Rosado, P. Amparo López-Jiménez, Francisco-Javier Sánchez-Romero, Pilar Conejos Fuertes and Modesto Pérez-Sánchez

Water 2020, 12(6), 1818; https://doi.org/10.3390/w12061818 - 24 Jun 2020

Cited by 17 | Viewed by 3480

Abstract

Sustainable development has been an idea raised in recent years. The results are related to the improvement and the use of new technologies to maximize efficiency in water management. However, energy consumption has been increasing as a consequence of new management and uses [...] Read more.

Sustainable development has been an idea raised in recent years. The results are related to the improvement and the use of new technologies to maximize efficiency in water management. However, energy consumption has been increasing as a consequence of new management and uses of water. Especially in pressurized water distribution systems, the use of pressure reduction valves (PRVs) increases the water usage efficiency but it decreases the energy consumption efficiency, since the valves dissipate energy that could be recovered. This research presents a proposal of a recovery system based on the installation of pumps used as turbines (PATs). These machines are located in different points of the high-pressure water distribution system in the Valencia Metropolitan System (Spain). An annual estimate of the theoretical recoverable energy as well as the “ideal” pump for each point were proposed. The theoretical recovered energy value was 847,301 kWh/year for a specific analyzed point. Besides, the characteristic curves of the PATs from a selected point were determined, estimating an improvement in the sustainable indexes. The calculus of these green parameters showed that the implementation of this solution caused a reduction in consumed energy of 1.50 kWh/m³. Full article

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

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30 pages, 10379 KiB

Open AccessEditor’s ChoiceArticle

A Dynamic Comparison Sustainability Study of Standard Wastewater Treatment System in the Straw Pulp Papermaking Process and Printing & Dyeing Papermaking Process Based on the Hybrid Neural Network and Emergy Framework

by Junxue Zhang, Lin Ma and Yanyan Yan

Water 2020, 12(6), 1781; https://doi.org/10.3390/w12061781 - 23 Jun 2020

Cited by 14 | Viewed by 3635

Abstract

Sustainability study of the standard wastewater treatment system is the pivotal procedure in the water protection field. In order to better study the sustainability of sewage treatment systems, wastewater treatment system of straw pulp papermaking (WTSPP) and wastewater treatment system of printing and [...] Read more.

Sustainability study of the standard wastewater treatment system is the pivotal procedure in the water protection field. In order to better study the sustainability of sewage treatment systems, wastewater treatment system of straw pulp papermaking (WTSPP) and wastewater treatment system of printing and dyeing and papermaking (WTPDP) have been selected to assess the sustainable level in China. Based on the hybrid neural network and emergy framework, WTSPP and WTPDP were considered and analyzed in this paper. Therein, three types of indicators were used to evaluate these two systems, including basic structure emergy indicators (BEI), functional emergy indicators (FEI), and eco-efficiency emergy indicators (EEI). Through the basic neural network model and detailed neural network model design, the iteration paths and algorithm operation diagram of WTSPP and WTPDP were designed and realized in this article. Primary contents include: (1) For WTSPP and WTPDP, nonrenewable resources emergy are both the primary contributor and account for roughly 62.5% and 53.7%, respectively. (2) As the important indicator group, the environmental loading ratio (ELR) is 176 in the WTSPP and 323 in the WTPDP, respectively. Emergy sustainability indicators (ESIs) in the WTSPP and WTPDP, are 0.015 and 0.014, respectively. (3) Depending on fluctuation degrees, WTSPP is better than WTPDP. The maximum fluctuation ranges of WTSPP and WTPDP are (3%, −27%) and (28%, 61%), respectively. (4) All neural network analysis results manifest that the emergy sustainability indicators (ESIs) of WTSPP and WTPDP are [0.0151, 0.011] and [0.0179, 0.0055] in view of a long-term predictive view, respectively. Full article

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

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10 pages, 3469 KiB

Open AccessEditor’s ChoiceArticle

Measurement of Wastewater Discharge in Sewer Pipes Using Image Analysis

by Hyon Wook Ji, Sung Soo Yoo, Bong-Jae Lee, Dan Daehyun Koo and Jeong-Hee Kang

Water 2020, 12(6), 1771; https://doi.org/10.3390/w12061771 - 22 Jun 2020

Cited by 31 | Viewed by 6962

Abstract

Generally, the amount of wastewater in sewerage pipes is measured using sensor-based devices such as submerged area velocity flow meters or non-contact flow meters. However, these flow meters do not provide accurate measurements because of impurities, corrosion, and measurement instability due to high [...] Read more.

Generally, the amount of wastewater in sewerage pipes is measured using sensor-based devices such as submerged area velocity flow meters or non-contact flow meters. However, these flow meters do not provide accurate measurements because of impurities, corrosion, and measurement instability due to high turbidity. However, cameras have advantages such as their low cost, easy service, and convenient operation compared to the sensors. Therefore, in this study, we examined the following three methods for measuring the flow rate by capturing images inside of a sewer pipe using a camera and analyzing the images to calculate the water level: direct visual inspection and recording, image processing, and deep learning. The MATLAB image processing toolbox was used for analysis. The image processing found the boundary line by adjusting the contrast of the image or removing noise; a network to find the boundary line between wastewater and sewer pipe was created after training the image segmentation results and placing them into three categories using deep learning. From the recognized water levels, geometrical features were used to identify the boundary lines, and flow velocities and flow rates were calculated from Manning’s equation. Using direct inspection and image-processing techniques, boundary lines in images were detected at rates of 12% and 53%, respectively. Although the deep-learning model required training, it demonstrated 100% water-level detection, thereby proving to be the most advantageous method. Moreover, there is enough potential to increase the accuracy of deep learning, and it can be a possible replacement for existing flow measurement sensors. Full article

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

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14 pages, 2548 KiB

Open AccessEditor’s ChoiceArticle

Analysis of the Possibility of Using the Plain CFD Model to Simulate Two-Phase Flows in Spatial Systems of Pressure Sewer Networks

by Piotr Siwicki, Marcin Krukowski, Jan Studziński, Bartosz Szeląg and Rafał Wojciechowski

Water 2020, 12(6), 1779; https://doi.org/10.3390/w12061779 - 22 Jun 2020

Cited by 2 | Viewed by 2800

Abstract

The paper analyzes the possibility of using the CFD (Computational Fluid Dynamics) method to predict the amount of sewage remaining in siphons after a full air blast of the pressure sewer system. For this purpose, the results from measurements carried out on a [...] Read more.

The paper analyzes the possibility of using the CFD (Computational Fluid Dynamics) method to predict the amount of sewage remaining in siphons after a full air blast of the pressure sewer system. For this purpose, the results from measurements carried out on a laboratory installation were compared with the results obtained from modelling using a spatial model (3D) and a plain model (2D) of the installation. To determine these models, the structure of the VOF (Volume of Fluid) model was used in the CFD method. The simulation calculations carried out make it possible to state that the use of the plain model with the development of the installation modelled in the plan does not result in significant deterioration of the obtained results. The possibility of using 2D models for modelling pumped sewer systems allows for a significant shortening of the calculation time, which, in practice, results in the possibility of modelling much larger and longer installations than is possible with 3D models. Full article

(This article belongs to the Special Issue Numerical Modeling and Simulation of Multi-Phase Flows)

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20 pages, 3942 KiB

Open AccessEditor’s ChoiceArticle

Experimental Characterization of the Hydraulic Jump Profile and Velocity Distribution in a Stilling Basin Physical Model

by Juan Francisco Macián-Pérez, Francisco José Vallés-Morán, Santiago Sánchez-Gómez, Marco De-Rossi-Estrada and Rafael García-Bartual

Water 2020, 12(6), 1758; https://doi.org/10.3390/w12061758 - 20 Jun 2020

Cited by 20 | Viewed by 5581

Abstract

The study of the hydraulic jump developed in stilling basins is complex to a high degree due to the intense velocity and pressure fluctuations and the significant air entrainment. It is this complexity, bound to the practical interest in stilling basins for energy [...] Read more.

The study of the hydraulic jump developed in stilling basins is complex to a high degree due to the intense velocity and pressure fluctuations and the significant air entrainment. It is this complexity, bound to the practical interest in stilling basins for energy dissipation purposes, which brings the importance of physical modeling into the spotlight. However, despite the importance of stilling basins in engineering, bibliographic studies have traditionally focused on the classical hydraulic jump. Therefore, the objective of this research was to study the characteristics of the hydraulic jump in a typified USBR II stilling basin, through a physical model. The free surface profile and the velocity distribution of the hydraulic jump developed within this structure were analyzed in the model. To this end, an experimental campaign was carried out, assessing the performance of both, innovative techniques such as the time-of-flight camera and traditional instrumentation like the Pitot tube. The results showed a satisfactory representation of the free surface profile and the velocity distribution, despite some discussed limitations. Furthermore, the instrumentation employed revealed the important influence of the energy dissipation devices on the flow properties. In particular, relevant differences were found for the hydraulic jump shape and the maximum velocity positions within the measured vertical profiles, when compared to classical hydraulic jumps. Full article

(This article belongs to the Special Issue Physical Modelling in Hydraulics Engineering)

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10 pages, 2006 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Water Resource Systems Analysis for Water Scarcity Management: The Thames Water Case Study

by Mark Morley and Dragan Savić

Water 2020, 12(6), 1761; https://doi.org/10.3390/w12061761 - 20 Jun 2020

Cited by 8 | Viewed by 6787

Abstract

Optimisation tools are a practical solution to problems involving the complex and interdependent constituents of water resource systems and offer the opportunity to engage with practitioners as an integral part of the optimisation process. A multiobjective genetic algorithm is employed in conjunction with [...] Read more.

Optimisation tools are a practical solution to problems involving the complex and interdependent constituents of water resource systems and offer the opportunity to engage with practitioners as an integral part of the optimisation process. A multiobjective genetic algorithm is employed in conjunction with a detailed water resource model to optimise the “Lower Thames Control Diagram”, a set of control curves subject to a large number of constraints. The Diagram is used to regulate abstraction of water for the public drinking water supply for London, UK, and to maintain downstream environmental and navigational flows. The optimisation is undertaken with the aim of increasing the amount of water that can be supplied (deployable output) through solely operational changes. A significant improvement of 33 Ml/day (1% or £59.4 million of equivalent investment in alternative resources) of deployable output was achieved through the optimisation, improving the performance of the system whilst maintaining the level of service constraints without negatively impacting on the amount of water released downstream. A further 0.2% (£11.9 million equivalent) was found to be realisable through an additional low-cost intervention. A more realistic comparison of solutions indicated even larger savings for the utility, as the baseline solution did not satisfy the basic problem constraints. The optimised configuration of the Lower Thames Control Diagram was adopted by the water utility and the environmental regulators and is currently in use. Full article

(This article belongs to the Special Issue Application of the Systems Approach to the Management of Complex Water Systems)

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19 pages, 3282 KiB

Open AccessEditor’s ChoiceArticle

Rainfall Variability and Trend Analysis of Rainfall in West Africa (Senegal, Mauritania, Burkina Faso)

by Zeineddine Nouaceur and Ovidiu Murarescu

Water 2020, 12(6), 1754; https://doi.org/10.3390/w12061754 - 19 Jun 2020

Cited by 37 | Viewed by 5908

Abstract

This study concerns the West African Sahel. The Sahelian climate is characterized by a long dry season and a rainy season which starts in June and ends in September–October. This latter season is associated with the process of oceanic moisture transfer to the [...] Read more.

This study concerns the West African Sahel. The Sahelian climate is characterized by a long dry season and a rainy season which starts in June and ends in September–October. This latter season is associated with the process of oceanic moisture transfer to the mainland (the West African Monsoon). This movement is governed by an overall moving of the meteorological equator and its low-pressure corridor (Intertropical Convergence Zone, ITCZ) towards the north, under the effect of the attraction of the Saharan thermal depressions and a greater vigor of the anticyclonic nuclei. This study was conducted on 27 Sahelian climatic stations in three countries (Burkina Faso, Mauritania, and Senegal). The method used to determine the modes of this variability and the trends of rainfall is the chronological graphic method of information processing (MGCTI) of the “Bertin Matrix” and continuous wavelets transform (CWT). Results show a rain resumption observed in the recent years over the Sahelian region and a convincing link with the surface temperature of the Atlantic Ocean. Full article

(This article belongs to the Special Issue Water Quality of Freshwater Ecosystems in a Temperate Climate)

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31 pages, 3862 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Improving Inter-Laboratory Reproducibility in Measurement of Biochemical Methane Potential (BMP)

by Sasha D. Hafner, Hélène Fruteau de Laclos, Konrad Koch and Christof Holliger

Water 2020, 12(6), 1752; https://doi.org/10.3390/w12061752 - 19 Jun 2020

Cited by 61 | Viewed by 8261

Abstract

Biochemical methane potential (BMP) tests used to determine the ultimate methane yield of organic substrates are not sufficiently standardized to ensure reproducibility among laboratories. In this contribution, a standardized BMP protocol was tested in a large inter-laboratory project, and results were used to [...] Read more.

Biochemical methane potential (BMP) tests used to determine the ultimate methane yield of organic substrates are not sufficiently standardized to ensure reproducibility among laboratories. In this contribution, a standardized BMP protocol was tested in a large inter-laboratory project, and results were used to quantify sources of variability and to refine validation criteria designed to improve BMP reproducibility. Three sets of BMP tests were carried out by more than thirty laboratories from fourteen countries, using multiple measurement methods, resulting in more than 400 BMP values. Four complex but homogenous substrates were tested, and additionally, microcrystalline cellulose was used as a positive control. Inter-laboratory variability in reported BMP values was moderate. Relative standard deviation among laboratories (RSD_R) was 7.5 to 24%, but relative range (RR) was 31 to 130%. Systematic biases were associated with both laboratories and tests within laboratories. Substrate volatile solids (VS) measurement and inoculum origin did not make major contributions to variability, but errors in data processing or data entry were important. There was evidence of negative biases in manual manometric and manual volumetric measurement methods. Still, much of the observed variation in BMP values was not clearly related to any of these factors and is probably the result of particular practices that vary among laboratories or even technicians. Based on analysis of calculated BMP values, a set of recommendations was developed, considering measurement, data processing, validation, and reporting. Recommended validation criteria are: (i) test duration at least 1% net 3 d, (ii) relative standard deviation for cellulose BMP not higher than 6%, and (iii) mean cellulose BMP between 340 and 395 NmL_CH4 g_VS⁻¹. Evidence from this large dataset shows that following the recommendations—in particular, application of validation criteria—can substantially improve reproducibility, with RSD_R < 8% and RR < 25% for all substrates. The cellulose BMP criterion was particularly important. Results show that is possible to measure very similar BMP values with different measurement methods, but to meet the recommended validation criteria, some laboratories must make changes to their BMP methods. To help improve the practice of BMP measurement, a new website with detailed, up-to-date guidance on BMP measurement and data processing was established. Full article

(This article belongs to the Special Issue Biomethane Potential Tests—A Key Tool for Anaerobic Digestion Research and Practice)

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15 pages, 552 KiB

Open AccessEditor’s ChoiceArticle

Scarce Water Resources and Cereal Import Dependency: The Role of Integrated Water Resources Management

by Bente Castro Campos, Yanjun Ren and Jens-Peter Loy

Water 2020, 12(6), 1750; https://doi.org/10.3390/w12061750 - 19 Jun 2020

Cited by 6 | Viewed by 4337

Abstract

This study globally analyzes the nonlinear relationship between cereal import dependency and total renewable water resources per capita by testing for potential thresholds in water resources. Data are from the Food and Agriculture Organization (FAO), and consider the years of 2002, 2007, and [...] Read more.

This study globally analyzes the nonlinear relationship between cereal import dependency and total renewable water resources per capita by testing for potential thresholds in water resources. Data are from the Food and Agriculture Organization (FAO), and consider the years of 2002, 2007, and 2012. The results show evident ceiling effects with a threshold of 1588 m³/(capita/year) in the multiple predictor model. Above this value, the total renewable water resources per capita no longer have a considerable effect on cereal import dependency. Importantly, we found that if integrated water resource management improves, cereal import dependency will increase for countries with total renewable water resources per capita between 1588 m³/(capita/year) and 5000 m³/(capita/year), but not for countries below or equal to the threshold of 1588 m³/(capita/year). Water-scarce countries above the threshold use cereal imports as a coping strategy to save limited national water resources. This strategy might be suggested to extremely water-scarce countries below the threshold to increase their water use efficiency. Global solidarity of grain exporters with water-scarce countries is required to guarantee their food security, while water-scarce countries need to overcome their skepticism of foreign dominance through food imports. Full article

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

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18 pages, 4833 KiB

Open AccessEditor’s ChoiceArticle

Retrieval of Soil Moisture by Integrating Sentinel-1A and MODIS Data over Agricultural Fields

by Yizhi Han, Xiaojing Bai, Wei Shao and Jie Wang

Water 2020, 12(6), 1726; https://doi.org/10.3390/w12061726 - 17 Jun 2020

Cited by 26 | Viewed by 4274

Abstract

Soil moisture is an essential variable in the land surface ecosystem, which plays an important role in agricultural drought monitoring, crop status monitoring, and crop yield prediction. High-resolution radar data can be combined with optical remote-sensing data to provide a new approach to [...] Read more.

Soil moisture is an essential variable in the land surface ecosystem, which plays an important role in agricultural drought monitoring, crop status monitoring, and crop yield prediction. High-resolution radar data can be combined with optical remote-sensing data to provide a new approach to estimate high-resolution soil moisture over vegetated areas. In this paper, the Sentinel-1A data and the Moderate Resolution Imaging Spectroradiometer (MODIS) data are combined to retrieve soil moisture over agricultural fields. The advanced integral equation model (AIEM) is utilized to calculate the scattering contribution of the bare soil surface. The water cloud model (WCM) is applied to model the backscattering coefficient of vegetated areas, which use two vegetation parameters to parameterize the scattering and attenuation properties of vegetation. Four different vegetation parameters extracted from MODIS products are combined to predict the scattering contribution of vegetation, including the leaf area index (LAI), the fraction of photosynthetically active radiation (FPAR), normalized difference vegetation index (NDVI), and the enhanced vegetation index (EVI). The effective roughness parameters are chosen to parameterize the AIEM. The Sentinel-1A and MODIS data in 2017 are used to calibrate the coupled model, and the datasets in 2018 are used for soil moisture estimation. The calibration results indicate that the Sentinel-1A backscattering coefficient can be accurately predicted by the coupled model with the Pearson correlation coefficient (R) ranging from 0.58 to 0.81 and a root mean square error (RMSE) ranging from 0.996 to 1.401 dB. The modeled results show that the retrieved soil moisture can capture the seasonal dynamics of soil moisture with R ranging from 0.74 to 0.81. With the different vegetation parameter combinations used for parameterizing the scattering contribution of the canopy, the importance of suitable vegetation parameters for describing the scattering and attenuation properties of vegetation is confirmed. The LAI is recommended to characterize the scattering properties. There is no obvious clue for selecting vegetation descriptors to characterize the attenuation properties of vegetation. These promising results confirm the feasibility and validity of the coupled model for soil moisture retrieval from the Sentinel-1A and MODIS data. Full article

(This article belongs to the Section Hydrology)

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18 pages, 2420 KiB

Open AccessEditor’s ChoiceArticle

Snowmelt-Driven Streamflow Prediction Using Machine Learning Techniques (LSTM, NARX, GPR, and SVR)

by Samit Thapa, Zebin Zhao, Bo Li, Lu Lu, Donglei Fu, Xiaofei Shi, Bo Tang and Hong Qi

Water 2020, 12(6), 1734; https://doi.org/10.3390/w12061734 - 17 Jun 2020

Cited by 62 | Viewed by 7165

Abstract

Although machine learning (ML) techniques are increasingly popular in water resource studies, they are not extensively utilized in modeling snowmelt. In this study, we developed a model based on a deep learning long short-term memory (LSTM) for snowmelt-driven discharge modeling in a Himalayan [...] Read more.

Although machine learning (ML) techniques are increasingly popular in water resource studies, they are not extensively utilized in modeling snowmelt. In this study, we developed a model based on a deep learning long short-term memory (LSTM) for snowmelt-driven discharge modeling in a Himalayan basin. For comparison, we developed the nonlinear autoregressive exogenous model (NARX), Gaussian process regression (GPR), and support vector regression (SVR) models. The snow area derived from moderate resolution imaging spectroradiometer (MODIS) snow images along with remotely sensed meteorological products were utilized as inputs to the models. The Gamma test was conducted to determine the appropriate input combination for the models. The shallow LSTM model with a hidden layer achieved superior results than the deeper LSTM models with multiple hidden layers. Out of seven optimizers tested, Adamax proved to be the aptest optimizer for this study. The evaluation of the ML models was done by the coefficient of determination (R2), mean absolute error (MAE), modified Kling–Gupta efficiency (KGE’), Nash–Sutcliffe efficiency (NSE), and root-mean-squared error (RMSE). The LSTM model (KGE’ = 0.99) enriched with snow cover input achieved the best results followed by NARX (KGE’ = 0.974), GPR (KGE’ = 0.95), and SVR (KGE’ = 0.949), respectively. The outcome of this study proves the applicability of the ML models, especially the LSTM model, in predicting snowmelt driven discharge in the data-scant mountainous watersheds. Full article

(This article belongs to the Section Hydrology)

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18 pages, 2765 KiB

Open AccessEditor’s ChoiceArticle

Effects of Land Use Changes on Streamflow and Sediment Yield in Atibaia River Basin—SP, Brazil

by Franciane Mendonça dos Santos, Rodrigo Proença de Oliveira and José Augusto Di Lollo

Water 2020, 12(6), 1711; https://doi.org/10.3390/w12061711 - 16 Jun 2020

Cited by 20 | Viewed by 4573

Abstract

The Soil and Water Assessment Tool (SWAT) is often used to evaluate the impacts of different land use scenarios on streamflow and sediment yield, but there is a need for some clear recommendations on how to select the parameter set that defines a [...] Read more.

The Soil and Water Assessment Tool (SWAT) is often used to evaluate the impacts of different land use scenarios on streamflow and sediment yield, but there is a need for some clear recommendations on how to select the parameter set that defines a given land use scenario and on what is the most appropriate methodology to change the selected parameters when describing possible future conditions. This paper reviews the SWAT formulation to identify the parameters that depend on the land use, performs a sensitivity analysis to determine the ones with larger impacts on the model results and discusses ways to consider future land use conditions. The case study is the Atibaia river basin, with 2838 km² (São Paulo, Brazil). The parameters identified by sensitivity analysis with the largest impacts on streamflow and sediment yield were the initial curve number for moisture condition II (CN), maximum canopy storage for each land use (CANMX) and the cover and management factor (USLE_C). The identification and appropriate parameter change can provide real estimates of the magnitudes in the land use changes, which were verified in this study. Such information can be used as an instrument for proposing improvements in the basin’s environmental quality and management. Full article

(This article belongs to the Special Issue Hydrological Impacts of Climate Change and Land Use)

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19 pages, 6689 KiB

Open AccessEditor’s ChoiceArticle

The Link between Permeable Interlocking Concrete Pavement (PICP) Design and Nutrient Removal

by Bodi Kimberly Liu and Neil P. Armitage

Water 2020, 12(6), 1714; https://doi.org/10.3390/w12061714 - 16 Jun 2020

Cited by 11 | Viewed by 4617

Abstract

The construction of ‘hard’ impermeable surfaces in urban areas results in the increased flow of stormwater runoff and its associated pollutants into downstream receiving waters. Permeable Pavement Systems (PPS) can help mitigate this. The most common type of PPS in South Africa is [...] Read more.

The construction of ‘hard’ impermeable surfaces in urban areas results in the increased flow of stormwater runoff and its associated pollutants into downstream receiving waters. Permeable Pavement Systems (PPS) can help mitigate this. The most common type of PPS in South Africa is permeable interlocking concrete pavement (PICP), but there is currently insufficient information available on the relative treatment performance of different PICP designs. This paper describes an investigation into the performance of ten different PICP systems constructed in the Civil Engineering Laboratory at the University of Cape Town for the treatment of various nutrients commonly found in stormwater runoff. It was found that removal efficiencies ranged from 27.5% to 78.7% for ammonia-nitrogen and from −37% to 11% for orthophosphate-phosphorus; whilst 4% to 20.2% more nitrite-nitrogen and 160% to 2580% more nitrate-nitrogen were simultaneously added. The presence of a geotextile resulted in higher ammonia-nitrogen removal efficiencies but also higher nitrate-nitrogen addition than those cells without—with small differences between various types. The cell with a permanently wet ‘sump’ had the highest nitrate-nitrogen addition of all. Lower pH results in higher nitrate-nitrogen concentrations, whilst the electrical conductivity strongly depends on the length of the periods between rainfall ‘seasons’, decreasing rapidly during wet periods but increasing during dry periods. Paver type also had a minor impact on nutrient removal. Full article

(This article belongs to the Special Issue Permeable Pavement Systems: Advances and Challenges in Stormwater Management)

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24 pages, 4999 KiB

Open AccessEditor’s ChoiceArticle

Baseline Conditions and Projected Future Hydro-Climatic Change in National Parks in the Conterminous United States

by William Battaglin, Lauren Hay, David J. Lawrence, Greg McCabe and Parker Norton

Water 2020, 12(6), 1704; https://doi.org/10.3390/w12061704 - 15 Jun 2020

Cited by 5 | Viewed by 3725

Abstract

The National Park Service (NPS) manages hundreds of parks in the United States, and many contain important aquatic ecosystems and/or threatened and endangered aquatic species vulnerable to hydro-climatic change. More effective management of park resources under future hydro-climatic uncertainty requires information on both [...] Read more.

The National Park Service (NPS) manages hundreds of parks in the United States, and many contain important aquatic ecosystems and/or threatened and endangered aquatic species vulnerable to hydro-climatic change. More effective management of park resources under future hydro-climatic uncertainty requires information on both baseline conditions and the range of projected future conditions. A monthly water balance model was used to assess baseline (1981–1999) conditions and a range of projected future hydro-climatic conditions in 374 NPS parks. General circulation model outputs representing 214 future climate simulations were used to drive the model. Projected future changes in air temperature (T), precipitation (p), and runoff (R) are expressed as departures from historical baselines. Climate simulations indicate increasing T by 2030 for all parks with 50th percentile simulations projecting increases of 1.67 °C or more in 50% of parks. Departures in 2030 p indicate a mix of mostly increases and some decreases, with 50th percentile simulations projecting increases in p in more than 70% of parks. Departures in R for 2030 are mostly decreases, with the 50th percentile simulations projecting decreases in R in more than 50% of parks in all seasons except winter. Hence, in many NPS parks, R is projected to decrease even when p is projected to increase because of increasing T in all parks. Projected changes in future hydro-climatic conditions can also be assessed for individual parks, and Rocky Mountain National Park and Congaree National Park are used as examples. Full article

(This article belongs to the Special Issue Using Large-Domain Hydrologic Modeling to Understand the Effects of Climate and Land Use on Water Availability)

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14 pages, 2745 KiB

Open AccessEditor’s ChoiceArticle

Accounting for the Three-Dimensional Distribution of Escherichia coli Concentrations in Pond Water in Simulations of the Microbial Quality of Water Withdrawn for Irrigation

by Matthew D. Stocker, Dong Jin Jeon, Ekaterina Sokolova, Hoonsoo Lee, Moon S. Kim and Yakov A. Pachepsky

Water 2020, 12(6), 1708; https://doi.org/10.3390/w12061708 - 15 Jun 2020

Cited by 6 | Viewed by 2741

Abstract

Evaluating the microbial quality of irrigation water is essential for the prevention of foodborne illnesses. Generic Escherichia coli (E. coli) is used as an indicator organism to estimate the microbial quality of irrigation water. Monitoring E. coli concentrations in irrigation water [...] Read more.

Evaluating the microbial quality of irrigation water is essential for the prevention of foodborne illnesses. Generic Escherichia coli (E. coli) is used as an indicator organism to estimate the microbial quality of irrigation water. Monitoring E. coli concentrations in irrigation water sources is commonly performed using water samples taken from a single depth. Vertical gradients of E. coli concentrations are typically not measured or are ignored; however, E. coli concentrations in water bodies can be expected to have horizontal and vertical gradients. The objective of this work was to research 3D distributions of E. coli concentrations in an irrigation pond in Maryland and to estimate the dynamics of E. coli concentrations at the water intake during the irrigation event using hydrodynamic modeling in silico. The study pond is about 22 m wide and 200 m long, with an average depth of 1.5 m. Three transects sampled at 50-cm depth intervals, along with intensive nearshore sampling, were used to develop the initial concentration distribution for the application of the environmental fluid dynamic code (EFDC) model. An eight-hour irrigation event was simulated using on-site data on the wind speed and direction. Substantial vertical and horizontal variations in E. coli concentrations translated into temporally varying concentrations at the intake. Additional simulations showed that the E. coli concentrations at the intake reflect the 3D distribution of E. coli in the limited pond section close to the intake. The 3D sampling revealed E. coli concentration hot spots at different depths across the pond. Measured and simulated 3D E. coli concentrations provide improved insights into the expected microbial water quality of irrigation water compared with 1D or 2D representations of the spatial variability of the indicator concentration. Full article

(This article belongs to the Special Issue Irrigation Management)

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22 pages, 3531 KiB

Open AccessEditor’s ChoiceArticle

Comparison of ERA5-Land and UERRA MESCAN-SURFEX Reanalysis Data with Spatially Interpolated Weather Observations for the Regional Assessment of Reference Evapotranspiration

by Anna Pelosi, Fabio Terribile, Guido D’Urso and Giovanni Battista Chirico

Water 2020, 12(6), 1669; https://doi.org/10.3390/w12061669 - 11 Jun 2020

Cited by 129 | Viewed by 9220

Abstract

Reanalysis data are being increasingly used as gridded weather data sources for assessing crop-reference evapotranspiration (ET₀) in irrigation water-budget analyses at regional scales. This study assesses the performances of ET₀ estimates based on weather data, respectively produced by two high-resolution [...] Read more.

Reanalysis data are being increasingly used as gridded weather data sources for assessing crop-reference evapotranspiration (ET₀) in irrigation water-budget analyses at regional scales. This study assesses the performances of ET₀ estimates based on weather data, respectively produced by two high-resolution reanalysis datasets: UERRA MESCAN-SURFEX (UMS) and ERA5-Land (E5L). The study is conducted in Campania Region (Southern Italy), with reference to the irrigation seasons (April–September) of years 2008–2018. Temperature, wind speed, vapor pressure deficit, solar radiation and ET₀ derived from reanalysis datasets, were compared with the corresponding estimates obtained by spatially interpolating data observed by a network of 18 automatic weather stations (AWSs). Statistical performances of the spatial interpolations were evaluated with a cross-validation procedure, by recursively applying universal kriging or ordinary kriging to the observed weather data. ERA5-Land outperformed UMS both in weather data and ET₀ estimates. Averaging over all 18 AWSs sites in the region, the normalized BIAS (nBIAS) was found less than 5% for all the databases. The normalized RMSE (nRMSE) for ET₀ computed with E5L data was 17%, while it was 22% with UMS data. Both performances were not far from those obtained by kriging interpolation, which presented an average nRMSE of 14%. Overall, this study confirms that reanalysis can successfully surrogate the unavailability of observed weather data for the regional assessment of ET₀. Full article

(This article belongs to the Special Issue Evaluation of Reanalysis Data in Meteorological and Climatological Applications: Spatial and Temporal Considerations)

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14 pages, 2834 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Reasons of Acceptance and Barriers of House Onsite Greywater Treatment and Reuse in Palestinian Rural Areas

by Rehab A. Thaher, Nidal Mahmoud, Issam A. Al-Khatib and Yung-Tse Hung

Water 2020, 12(6), 1679; https://doi.org/10.3390/w12061679 - 11 Jun 2020

Cited by 24 | Viewed by 5456

Abstract

In the last twenty years, house onsite wastewater management systems have been increasing in the West Bank’s rural areas. The aim of this research was to reveal, in the context of providing onsite Grey Water Treatment Plants (GWTPs) for wastewater management in the [...] Read more.

In the last twenty years, house onsite wastewater management systems have been increasing in the West Bank’s rural areas. The aim of this research was to reveal, in the context of providing onsite Grey Water Treatment Plants (GWTPs) for wastewater management in the rural communities in Palestine, the local population’s perceptions, in the sense of acceptance of and barriers towards such a type of wastewater management, so as to figure out successes, failures and lessons. The data collection tool was a questionnaire that targeted the households served with GWTPs. The findings show that 13% of the total constructed treatment plants were not operative. The most important barrier as mentioned by 66.5% is odor emission and insect infestation. Then, 25.1% of the implementing agencies never monitor or check the treatment plants, and 59.3% of them monitor and check the plants only during the first 2–3 months. The next barrier is inadequate beneficiary experience in operation and maintenance. Health concerns regarding quality of crops irrigated by treated grey water were another barrier. The results revealed that the reuse of treated grey water in irrigation was the main incentive for GWTPs as stated by 88.0% of beneficiaries. The second incentive was the saving of cesspit discharge frequency and its financial consequences, as stated by 71.3%. Finally, 72.5% of the beneficiaries stated that they had a water shortage before implementing GWTPs, and the GWTPs contributed to solving it. The highest percentage (82.6%) of beneficiaries accepted the treatment units because of their willingness to reuse treated water for irrigation and agricultural purposes. Education level has an impact on GWTP acceptance, with 73% of not educated beneficiaries being satisfied and 58.8% of educated people being satisfied. Islamic religion is considered a driver for accepting reuse of treated grey water in irrigation, according to the majority of people (70%). Women play a major role on GWTP management; 68.9% of the treatment systems are run by men side-by-side with women (fathers and mothers), and 24% are run completely by women. The majority of GWTP beneficiaries (70.4%) are satisfied with GWTPs. Little effort is required for operation and maintenance, with only an average of 0.4 working hours per week. Therefore, house onsite grey water management systems are acceptable in rural communities, but attention should be given to the reasons of acceptance and barriers highlighted in this research. Full article

(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment)

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22 pages, 644 KiB

Open AccessEditor’s ChoiceArticle

Agenda Setting in Water and IWRM: Discourse Analysis of Water Policy Debate in Pakistan

by Muhammad Arfan, Kamran Ansari, Asmat Ullah, Daniyal Hassan, Altaf Ali Siyal and Shaofeng Jia

Water 2020, 12(6), 1656; https://doi.org/10.3390/w12061656 - 10 Jun 2020

Cited by 19 | Viewed by 9748

Abstract

This article explores the water policy narrative in Pakistan, and identifies its historical trajectories and influences, as well as the impact of the global agenda setting of water for 2030. For this purpose, water sector reforms in Pakistan are examined as a case [...] Read more.

This article explores the water policy narrative in Pakistan, and identifies its historical trajectories and influences, as well as the impact of the global agenda setting of water for 2030. For this purpose, water sector reforms in Pakistan are examined as a case study. The National Water Policy (NWP) 2018 and Participatory Irrigation Management (PIM) reforms are critically evaluated and loopholes identified, in terms of both theoretical aspects and constraints in their practical implementation. The overall analysis reveals that the engineering narrative is dominant in policy circles and large-scale infrastructure construction is seen as an exceptional measure to overcome the current loss of storage potential due to sedimentation. On the other hand, the adoption of the Integrated Water Resource Management (IWRM) framework reflects the desire of state institutions to imbue water policy reform with international credibility. The IWRM framework has been adopted as isomorphic mimicry to appease international financing institutions and donors. PIM reform is thus far from delivering the desired results due to ideological battles among new (i.e., the Participatory Farmers Institution) and traditional bureaucratic irrigation institutions. As adopted, the global agenda setting of water, in the shape of IWRM, is a repackaging of existing activities, and prevents alternative thinking in the setting of water priorities according to developmental needs. Full article

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

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24 pages, 6651 KiB

Open AccessEditor’s ChoiceReview

Constructed Wetlands for Sustainable Wastewater Treatment in Hot and Arid Climates: Opportunities, Challenges and Case Studies in the Middle East

by Alexandros I. Stefanakis

Water 2020, 12(6), 1665; https://doi.org/10.3390/w12061665 - 10 Jun 2020

Cited by 114 | Viewed by 18545

Abstract

Many countries and regions around the world are facing a continuously growing pressure on their limited freshwater resources, particularly those under hot and arid climates. Higher water demand than availability led to over-abstraction and deterioration of the available freshwater resources’ quality. In this [...] Read more.

Many countries and regions around the world are facing a continuously growing pressure on their limited freshwater resources, particularly those under hot and arid climates. Higher water demand than availability led to over-abstraction and deterioration of the available freshwater resources’ quality. In this context, wastewater, if properly treated, can represent a new water source added in the local water balance, particularly in regions of Colorado, California, Australia, China and in the wide region of the Middle East, which is characterized as one of most water-stressed regions in the world. This article summarizes the status of wastewater treatment and management in the Middle East and discusses the challenges, the various barriers and also the opportunities that arise by introducing the sustainable technology of Constructed Wetlands in the region. Furthermore, the aim of the article is to provide a better insight into the possibility and feasibility of a wider implementation of this green technology under the hot and arid climate of Middle East by presenting several successful case studies of operating Constructed Wetlands facilities in the region for the treatment of various wastewater sources. Full article

(This article belongs to the Special Issue Wetlands in Action: Sustainable Water Management and Resource Recovery)

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21 pages, 15586 KiB

Open AccessEditor’s ChoiceArticle

Using 1D HEC-RAS Modeling and LiDAR Data to Improve Flood Hazard Maps Accuracy: A Case Study from Jijia Floodplain (NE Romania)

by Elena Huţanu, Alin Mihu-Pintilie, Andrei Urzica, Larisa Elena Paveluc, Cristian Constantin Stoleriu and Adrian Grozavu

Water 2020, 12(6), 1624; https://doi.org/10.3390/w12061624 - 6 Jun 2020

Cited by 55 | Viewed by 9434

Abstract

The ability to extract flood hazard settings in highly vulnerable areas like populated floodplains by using new computer algorithms and hydraulic modeling software is an important aspect of any flood mitigation efforts. In this framework, the 1D/2D hydraulic models, which were generated based [...] Read more.

The ability to extract flood hazard settings in highly vulnerable areas like populated floodplains by using new computer algorithms and hydraulic modeling software is an important aspect of any flood mitigation efforts. In this framework, the 1D/2D hydraulic models, which were generated based on a Light Detection and Ranging (LiDAR) derivate Digital Elevation Model (DEM) and processed within Geographical Information Systems (GIS), can improve large-scale flood hazard maps accuracy. In this study, we developed the first flood vulnerability assessment for 1% (100-year) and 0.1% (1000-year) recurrence intervals within the Jijia floodplain (north-eastern Romania), based on 1D HEC-RAS hydraulic modeling and LiDAR derivate DEM with 0.5 m spatial resolution. The results were compared with official flood hazards maps developed for the same recurrence intervals by the hydrologists of National Administration “Romanian Waters” (NARW) based on MIKE SHE modeling software and a DEM with 2 m spatial resolutions. It was revealed that the 1D HEC-RAS provides a more realistic perspective about the possible flood threats within Jijia floodplain and improves the accuracy of the official flood hazard maps obtained according to Flood Directive 2007/60/EC. Full article

(This article belongs to the Special Issue Hydrology, Water Resources Management and Protection of the Marine Environment-Selected Papers from the 16th International Conference on Environmental Science and Technology (CEST2019))

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17 pages, 2589 KiB

Open AccessEditor’s ChoiceArticle

A Novel Methodology for Prediction Urban Water Demand by Wavelet Denoising and Adaptive Neuro-Fuzzy Inference System Approach

by Salah L. Zubaidi, Hussein Al-Bugharbee, Sandra Ortega-Martorell, Sadik Kamel Gharghan, Ivan Olier, Khalid S. Hashim, Nabeel Saleem Saad Al-Bdairi and Patryk Kot

Water 2020, 12(6), 1628; https://doi.org/10.3390/w12061628 - 6 Jun 2020

Cited by 97 | Viewed by 6512

Abstract

Accurate and reliable urban water demand prediction is imperative for providing the basis to design, operate, and manage water system, especially under the scarcity of the natural water resources. A new methodology combining discrete wavelet transform (DWT) with an adaptive neuro-fuzzy inference system [...] Read more.

Accurate and reliable urban water demand prediction is imperative for providing the basis to design, operate, and manage water system, especially under the scarcity of the natural water resources. A new methodology combining discrete wavelet transform (DWT) with an adaptive neuro-fuzzy inference system (ANFIS) is proposed to predict monthly urban water demand based on several intervals of historical water consumption. This ANFIS model is evaluated against a hybrid crow search algorithm and artificial neural network (CSA-ANN), since these methods have been successfully used recently to tackle a range of engineering optimization problems. The study outcomes reveal that (1) data preprocessing is essential for denoising raw time series and choosing the model inputs to render the highest model performance; (2) both methodologies, ANFIS and CSA-ANN, are statistically equivalent and capable of accurately predicting monthly urban water demand with high accuracy based on several statistical metric measures such as coefficient of efficiency (0.974, 0.971, respectively). This study could help policymakers to manage extensions of urban water system in response to the increasing demand with low risk related to a decision. Full article

(This article belongs to the Special Issue Advanced Applications of Electrocoagulation in Water and Wastewater)

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28 pages, 1005 KiB

Open AccessEditor’s ChoiceReview

On the Coronaviruses and Their Associations with the Aquatic Environment and Wastewater

by Adrian Wartecki and Piotr Rzymski

Water 2020, 12(6), 1598; https://doi.org/10.3390/w12061598 - 4 Jun 2020

Cited by 42 | Viewed by 14998

Abstract

The outbreak of Coronavirus Disease 2019 (COVID-19), a severe respiratory disease caused by betacoronavirus SARS-CoV-2, in 2019 that further developed into a pandemic has received an unprecedented response from the scientific community and sparked a general research interest into the biology and ecology [...] Read more.

The outbreak of Coronavirus Disease 2019 (COVID-19), a severe respiratory disease caused by betacoronavirus SARS-CoV-2, in 2019 that further developed into a pandemic has received an unprecedented response from the scientific community and sparked a general research interest into the biology and ecology of Coronaviridae, a family of positive-sense single-stranded RNA viruses. Aquatic environments, lakes, rivers and ponds, are important habitats for bats and birds, which are hosts for various coronavirus species and strains and which shed viral particles in their feces. It is therefore of high interest to fully explore the role that aquatic environments may play in coronavirus spread, including cross-species transmissions. Besides the respiratory tract, coronaviruses pathogenic to humans can also infect the digestive system and be subsequently defecated. Considering this, it is pivotal to understand whether wastewater can play a role in their dissemination, particularly in areas with poor sanitation. This review provides an overview of the taxonomy, molecular biology, natural reservoirs and pathogenicity of coronaviruses; outlines their potential to survive in aquatic environments and wastewater; and demonstrates their association with aquatic biota, mainly waterfowl. It also calls for further, interdisciplinary research in the field of aquatic virology to explore the potential hotspots of coronaviruses in the aquatic environment and the routes through which they may enter it. Full article

(This article belongs to the Special Issue Coronaviruses and Water under the One Health Perspective)

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23 pages, 12377 KiB

Open AccessEditor’s ChoiceArticle

Impact of Climate Change on the Hydrological Regimes in Bavaria

by Benjamin Poschlod, Florian Willkofer and Ralf Ludwig

Water 2020, 12(6), 1599; https://doi.org/10.3390/w12061599 - 4 Jun 2020

Cited by 19 | Viewed by 5872

Abstract

This study assesses the change of the seasonal runoff characteristics in 98 catchments in central Europe between the reference period of 1981–2010, and in the near future (2011–2040), mid future (2041–2070) and far future (2071–2099). Therefore, a large ensemble of 50 hydrological simulations [...] Read more.

This study assesses the change of the seasonal runoff characteristics in 98 catchments in central Europe between the reference period of 1981–2010, and in the near future (2011–2040), mid future (2041–2070) and far future (2071–2099). Therefore, a large ensemble of 50 hydrological simulations featuring the model WaSiM-ETH driven by a 50-member ensemble of the Canadian Regional Climate Model, version 5 (CRCM5) under the emission scenario Representative Concentration Pathway (RCP 8.5) is analyzed. A hierarchical cluster analysis is applied to group the runoff characteristics into six flow regime classes. In the study area, (glacio-)nival, nival (transition), nivo-pluvial and three different pluvial classes are identified. We find that the characteristics of all six regime groups are severely affected by climate change in terms of the amplitude and timing of the monthly peaks and sinks. According to our simulations, the monthly peak of nival regimes will occur earlier in the season and the relative importance of rainfall increases towards the future. Pluvial regimes will become less balanced with higher normalized monthly discharge during January to March and a strong decrease during May to October. In comparison to the reference period, 8% of catchments will shift to another regime class until 2011–2040, whereas until 2041–2070 and 2071–2099, 23% and 43% will shift to another class, respectively. Full article

(This article belongs to the Special Issue Hydrology of Rivers and Lakes under Climate Change)

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23 pages, 3090 KiB

Open AccessEditor’s ChoiceArticle

Application of Multivariate Statistical Analysis in the Development of a Surrogate Water Quality Index (WQI) for South African Watersheds

by Talent Diotrefe Banda and Muthukrishnavellaisamy Kumarasamy

Water 2020, 12(6), 1584; https://doi.org/10.3390/w12061584 - 2 Jun 2020

Cited by 62 | Viewed by 6329

Abstract

Water quality indices (WQIs) are customarily associated with heavy data input demand, making them more rigorous and bulky. Such burdensome attributes are too taxing, time-consuming, and command a significant amount of resources to implement, which discourages their application and directly influences water resource [...] Read more.

Water quality indices (WQIs) are customarily associated with heavy data input demand, making them more rigorous and bulky. Such burdensome attributes are too taxing, time-consuming, and command a significant amount of resources to implement, which discourages their application and directly influences water resource monitoring. It is then imperative to focus on developing compatible, simpler, and less-demanding WQI tools, but with equally matching computational ability. Surrogate models are the best fitting, conforming to the prescribed features and scope. Therefore, this study attempts to provide a surrogate WQI as an alternative water quality monitoring tool that requires fewer inputs, minimal effort, and marginal resources to function. Accordingly, multivariate statistical techniques which include principal component analysis (PCA), hierarchical clustering analysis (HCA) and multiple linear regression (MLR) are applied primarily to determine four proxy variables and establish relevant model coefficients. As a result, chlorophyll-a, electrical conductivity, pondus Hydrogenium and turbidity are the final four proxy variables retained. A vital feature of the proposed surrogate index is that the input parameters qualify for inclusion into remote monitoring systems; henceforth, the model can be applied in remote monitoring programs. Reflecting on the model validation results, the proposed surrogate WQI is considered scientifically stable, with a minimum magnitude of divergence from the ideal water quality values. More importantly, the model displayed a predictive pattern identical to the ideal graph, matching on both index scores and classification values. The established surrogate model is an important milestone with the potential of promoting water resource monitoring and assisting in capturing of spatial and temporal changes in South African river catchments. This paper aims at outlining the methods used in developing the surrogate water quality index and document the results achieved. Full article

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

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32 pages, 3294 KiB

Open AccessEditor’s ChoiceArticle

Analysis of the Most Severe Flood Events in Turkey (1960–2014): Which Triggering Mechanisms and Aggravating Pathways Can be Identified?

by Gamze Koç, Theresia Petrow and Annegret H. Thieken

Water 2020, 12(6), 1562; https://doi.org/10.3390/w12061562 - 30 May 2020

Cited by 20 | Viewed by 4941

Abstract

The most severe flood events in Turkey were determined for the period 1960–2014 by considering the number of fatalities, the number of affected people, and the total economic losses as indicators. The potential triggering mechanisms (i.e., atmospheric circulations and precipitation amounts) and aggravating [...] Read more.

The most severe flood events in Turkey were determined for the period 1960–2014 by considering the number of fatalities, the number of affected people, and the total economic losses as indicators. The potential triggering mechanisms (i.e., atmospheric circulations and precipitation amounts) and aggravating pathways (i.e., topographic features, catchment size, land use types, and soil properties) of these 25 events were analyzed. On this basis, a new approach was developed to identify the main influencing factor per event and to provide additional information for determining the dominant flood occurrence pathways for severe floods. The events were then classified through hierarchical cluster analysis. As a result, six different clusters were found and characterized. Cluster 1 comprised flood events that were mainly influenced by drainage characteristics (e.g., catchment size and shape); Cluster 2 comprised events aggravated predominantly by urbanization; steep topography was identified to be the dominant factor for Cluster 3; extreme rainfall was determined as the main triggering factor for Cluster 4; saturated soil conditions were found to be the dominant factor for Cluster 5; and orographic effects of mountain ranges characterized Cluster 6. This study determined pathway patterns of the severe floods in Turkey with regard to their main causal or aggravating mechanisms. Accordingly, geomorphological properties are of major importance in large catchments in eastern and northeastern Anatolia. In addition, in small catchments, the share of urbanized area seems to be an important factor for the extent of flood impacts. This paper presents an outcome that could be used for future urban planning and flood risk prevention studies to understand the flood mechanisms in different regions of Turkey. Full article

(This article belongs to the Section Hydrology)

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17 pages, 10236 KiB

Open AccessEditor’s ChoiceArticle

Assessment of Restorative Maintenance Practices on the Infiltration Capacity of Permeable Pavement

by Mari E. Danz, William R. Selbig and Nicolas H. Buer

Water 2020, 12(6), 1563; https://doi.org/10.3390/w12061563 - 30 May 2020

Cited by 20 | Viewed by 5174

Abstract

Permeable pavement has the potential to be an effective tool in managing stormwater runoff through retention of sediment and other contaminants associated with urban development. The infiltration capacity of permeable pavement declines as more sediment is captured, thereby reducing its ability to treat [...] Read more.

Permeable pavement has the potential to be an effective tool in managing stormwater runoff through retention of sediment and other contaminants associated with urban development. The infiltration capacity of permeable pavement declines as more sediment is captured, thereby reducing its ability to treat runoff. Regular restorative maintenance practices can alleviate this issue and prolong the useful life and benefits of the system. Maintenance practices used to restore the infiltration capacity of permeable pavement were evaluated on three surfaces: Permeable interlocking concrete pavers (PICP), pervious concrete (PC), and porous asphalt (PA). Each of the three test plots received a similar volume of runoff and sediment load from an adjacent, impervious asphalt parking lot. Six different maintenance practices were evaluated over a four-year period: Hand-held pressure washer and vacuum, leaf blower and push broom, vacuum-assisted street cleaner, manual disturbance of PICP aggregate, pressure washing and vacuuming, and compressed air and vacuuming. Of the six practices tested, five were completed on PICP, four on PC, and two on PA. Nearly all forms of maintenance resulted in increased average surface infiltration rates. Increases ranged from 94% to 1703% for PICP, 5% to 169% for PC, and 16% to 40% for PA. Disruption of the aggregate between the joints of PICP, whether by simple hand tools or sophisticated machinery, resulted in significant (p ≤ 0.05) gains in infiltration capacity. Sediment penetrated into the solid matrix of the PC and PA, making maintenance practices using a high-pressure wash followed by high-suction vacuum the most effective for these permeable pavement types. In all instances, when the same maintenance practice was done on multiple surfaces, PICP showed the greatest recovery in infiltration capacity. Full article

(This article belongs to the Section Urban Water Management)

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24 pages, 5667 KiB

Open AccessEditor’s ChoiceArticle

Novel Ensembles of Deep Learning Neural Network and Statistical Learning for Flash-Flood Susceptibility Mapping

by Romulus Costache, Phuong Thao Thi Ngo and Dieu Tien Bui

Water 2020, 12(6), 1549; https://doi.org/10.3390/w12061549 - 29 May 2020

Cited by 60 | Viewed by 5157

Abstract

This study aimed to assess flash-flood susceptibility using a new hybridization approach of Deep Neural Network (DNN), Analytical Hierarchy Process (AHP), and Frequency Ratio (FR). A catchment area in south-eastern Romania was selected for this proposed approach. In this regard, a geospatial database [...] Read more.

This study aimed to assess flash-flood susceptibility using a new hybridization approach of Deep Neural Network (DNN), Analytical Hierarchy Process (AHP), and Frequency Ratio (FR). A catchment area in south-eastern Romania was selected for this proposed approach. In this regard, a geospatial database of the flood with 178 flood locations and with 10 flash-flood predictors was prepared and used for this proposed approach. AHP and FR were used for processing and coding the predictors into a numeric format, whereas DNN, which is a powerful and state-of-the-art probabilistic machine leaning, was employed to build an inference flash-flood model. The reliability of the models was verified with the help of Receiver Operating Characteristic (ROC) Curve, Area Under Curve (AUC), and several statistical measures. The result shows that the two proposed ensemble models, DNN-AHP and DNN-FR, are capable of predicting future flash-flood areas with accuracy higher than 92%; therefore, they are a new tool for flash-flood studies. Full article

(This article belongs to the Special Issue Droughts and Floods Assessment and Monitoring Using Remote Sensing and Geospatial Techniques)

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32 pages, 2758 KiB

Open AccessEditor’s ChoiceReview

Chemically Modified Biosorbents and Their Role in the Removal of Emerging Pharmaceutical Waste in the Water System

by Adewale Adewuyi

Water 2020, 12(6), 1551; https://doi.org/10.3390/w12061551 - 29 May 2020

Cited by 149 | Viewed by 14606

Abstract

Presence of pharmaceutically active compounds (PACs) as emerging contaminants in water is a major concern. Recent reports have confirmed the presence of PACs in natural and wastewater systems, which have caused several problems indicating the urgent need for their removal. The current review [...] Read more.

Presence of pharmaceutically active compounds (PACs) as emerging contaminants in water is a major concern. Recent reports have confirmed the presence of PACs in natural and wastewater systems, which have caused several problems indicating the urgent need for their removal. The current review evaluates the role of chemically modified biosorbents in the removal of PACs in water. Reported biosorbents include plant and animal solid waste, microorganisms and bio-composite. Bio-composites exhibited better prospects when compared with other biosorbents. Types of chemical treatment reported include acid, alkaline, solvent extraction, metal salt impregnation and surface grafting, with alkaline treatment exhibiting better results when compared with other treatments. The biosorption processes mostly obeyed the pseudo-second-order model and the Langmuir isotherm model in a process described mainly by ionic interaction. Desorption and regeneration capacity are very important in selecting an appropriate biosorbent for the biosorption process. Depending on the type of biosorbent, the cost of water treatment per million liters of water was estimated as US $10–US $200, which presents biosorption as a cheap process compared to other known water treatment processes. However, there is a need to conduct large-scale studies on the biosorption process for removing PACs in water. Full article

(This article belongs to the Special Issue Adsorbents for Water and Wastewater Treatment and Resource Recovery)

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18 pages, 280 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Hydro-Economic Modelling for Water-Policy Assessment Under Climate Change at a River Basin Scale: A Review

by Alfonso Expósito, Felicitas Beier and Julio Berbel

Water 2020, 12(6), 1559; https://doi.org/10.3390/w12061559 - 29 May 2020

Cited by 39 | Viewed by 6006

Abstract

Hydro-economic models (HEMs) constitute useful instruments to assess water-resource management and inform water policy. In the last decade, HEMs have achieved significant advances regarding the assessment of the impacts of water-policy instruments at a river basin or catchment level in the context of [...] Read more.

Hydro-economic models (HEMs) constitute useful instruments to assess water-resource management and inform water policy. In the last decade, HEMs have achieved significant advances regarding the assessment of the impacts of water-policy instruments at a river basin or catchment level in the context of climate change (CC). This paper offers an overview of the alternative approaches used in river-basin hydro-economic modelling to address water-resource management issues and CC during the past decade. Additionally, it analyses how uncertainty and risk factors of global CC have been treated in recent HEMs, offering a discussion on these last advances. As the main conclusion, current challenges in the realm of hydro-economic modelling include the representation of the food-energy-water nexus, the successful representation of micro-macro linkages and feedback loops between the socio-economic model components and the physical side, and the treatment of CC uncertainties and risks in the analysis. Full article

(This article belongs to the Special Issue Institutions and Economics of Water Scarcity and Droughts)

19 pages, 6896 KiB

Open AccessEditor’s ChoiceArticle

Development Trends and Frontiers of Ocean Big Data Research Based on CiteSpace

by Jiajing Wu, Dongning Jia, Zhiqiang Wei and Dou Xin

Water 2020, 12(6), 1560; https://doi.org/10.3390/w12061560 - 29 May 2020

Cited by 21 | Viewed by 4812

Abstract

Modern socio-economic development and climate prediction depend greatly on the application of ocean big data. With the accelerated development of ocean observation methods and the continuous improvement of the big data science, the challenges of multiple data sources and data diversity have emerged [...] Read more.

Modern socio-economic development and climate prediction depend greatly on the application of ocean big data. With the accelerated development of ocean observation methods and the continuous improvement of the big data science, the challenges of multiple data sources and data diversity have emerged in the ocean field. As a result, the current data magnitude has reached the terabyte scale. Currently, the traditional theoretical foundation and technical methods have their inherent limitations and demerits that cannot satisfied the temporal and spatial attributes of the current ocean big data. Numerous scholars and countries were involved in ocean big data research. To explore the focus and current status, and determine the topics of research on bursts and acquisition of trend related to ocean big data, 400 articles between 1990 and 2019 were collected from the “Web of Science.” Combined with visualization software CiteSpace, bibliometrics method and literature combing technology, the pivotal literature related to ocean big data, including significant level countries, institutions, authors, journals and keywords were recognized. A synthetical analysis has revealed research hot spots and research frontiers. The purpose of this study is to provide researchers and practitioners in the field of ocean big data with the main research domains and research hotspots, and orientation for further research. Full article

(This article belongs to the Section Oceans and Coastal Zones)

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22 pages, 2264 KiB

Open AccessEditor’s ChoiceArticle

Development of a Universal Water Quality Index (UWQI) for South African River Catchments

by Talent Diotrefe Banda and Muthukrishnavellaisamy Kumarasamy

Water 2020, 12(6), 1534; https://doi.org/10.3390/w12061534 - 28 May 2020

Cited by 29 | Viewed by 11957

Abstract

The assessment of water quality has turned to be an ultimate goal for most water resource and environmental stakeholders, with ever-increasing global consideration. Against this backdrop, various tools and water quality guidelines have been adopted worldwide to govern water quality deterioration and institute [...] Read more.

The assessment of water quality has turned to be an ultimate goal for most water resource and environmental stakeholders, with ever-increasing global consideration. Against this backdrop, various tools and water quality guidelines have been adopted worldwide to govern water quality deterioration and institute the sustainable use of water resources. Water quality impairment is mainly associated with a sudden increase in population and related proceedings, which include urbanization, industrialization and agricultural production, among others. Such socio-economic activities accelerate water contamination and cause pollution stress to the aquatic environment. Scientifically based water quality index (WQI) models are then essentially important to measure the degree of contamination and advise whether specific water resources require restoration and to what extent. Such comprehensive evaluations reflect the integrated impact of adverse parameter concentrations and assist in the prioritization of remedial actions. WQI is a simple, yet intelligible and systematically structured, indexing scale beneficial for communicating water quality data to non-technical individuals, policymakers and, more importantly, water scientists. The index number is normally presented as a relative scale ranging from zero (worst quality) to one hundred (best quality). WQIs simplify and streamline what would otherwise be impractical assignments, thus justifying the efforts of developing water quality indices (WQIs). Generally, WQIs are not designed for broad applications; they are customarily developed for specific watersheds and/or regions, unless different basins share similar attributes and test a comparable range of water quality parameters. Their design and formation are governed by their intended use together with the degree of accuracy required, and such technicalities ultimately define the application boundaries of WQIs. This is perhaps the most demanding scientific need—that is, to establish a universal water quality index (UWQI) that can function in most, if not all, the catchments in South Africa. In cognizance of such a need, this study attempts to provide an index that is not limited to certain application boundaries, with a contribution that is significant not only to the authors, but also to the nation at large. The proposed WQI is based on the weighted arithmetic sum method, with parameters, weight coefficients and sub-index rating curves established through expert opinion in the form of the participation-based Rand Corporation’s Delphi Technique and extracts from the literature. UWQI functions with thirteen explanatory variables, which are NH₃, Ca, Cl, Chl-a, EC, F, CaCO₃, Mg, Mn, NO₃, pH, SO₄ and turbidity (NTU). Based on the model validation analysis, UWQI is considered robust and technically stable, with negligible variation from the ideal values. Moreover, the prediction pattern corresponds to the ideal graph with comparable index scores and identical classification grades, which signifies the readiness of the model to appraise water quality status across South African watersheds. The research article intends to substantiate the methods used and document the results achieved. Full article

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

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39 pages, 6143 KiB

Open AccessEditor’s ChoiceReview

Challenges and Opportunities for Sustainable Management of Water Resources in the Island of Crete, Greece

by V. A. Tzanakakis, A. N. Angelakis, N. V. Paranychianakis, Y. G. Dialynas and G. Tchobanoglous

Water 2020, 12(6), 1538; https://doi.org/10.3390/w12061538 - 28 May 2020

Cited by 54 | Viewed by 13190

Abstract

Crete, located in the South Mediterranean Sea, is characterized by long coastal areas, varied terrain relief and geology, and great spatial and inter-annual variations in precipitation. Under average meteorological conditions, the island is water-sufficient (967 mm precipitation; theoretical water potential 3425.89 hm³ [...] Read more.

Crete, located in the South Mediterranean Sea, is characterized by long coastal areas, varied terrain relief and geology, and great spatial and inter-annual variations in precipitation. Under average meteorological conditions, the island is water-sufficient (967 mm precipitation; theoretical water potential 3425.89 hm³; and total water use 610 hm³). Agriculture is by far the greatest user of water (78% of total water use), followed by domestic use (21%). Despite the high average water availability, water scarcity events commonly occur, particularly in the eastern-south part of the island, driven by local climatic conditions and seasonal or geographical mismatches between water availability and demand. Other critical issues in water management include the over-exploitation of groundwater, accounting for 93% of the water used in agriculture; low water use efficiencies in the farms; limited use of non-conventional water sources (effluent reuse); lack of modern frameworks of control and monitoring; and inadequate cooperation among stakeholders. These deficiencies impact adversely water use efficiency, deteriorate quality of water resources, increase competition for water and water pricing, and impair agriculture and environment. Moreover, the water-limited areas may display low adaptation potential to climate variability and face increased risks for the human-managed and natural ecosystems. The development of appropriate water governance frameworks that promote the development of integrated water management plans and allow concurrently flexibility to account for local differentiations in social-economic favors is urgently needed to achieve efficient water management and to improve the adaptation to the changing climatic conditions. Specific corrective actions may include use of alternative water sources (e.g., treated effluent and brackish water), implementation of efficient water use practices, re-formation of pricing policy, efficient control and monitoring, and investment in research and innovation to support the above actions. It is necessary to strengthen the links across stakeholders (e.g., farmers, enterprises, corporations, institutes, universities, agencies, and public authorities), along with an effective and updated governance framework to address the critical issues in water management, facilitate knowledge transfer, and promote the efficient use of non-conventional water resources. Full article

(This article belongs to the Special Issue Water Supply and Water Scarcity)

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16 pages, 3705 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Tillage Versus No-Tillage. Soil Properties and Hydrology in an Organic Persimmon Farm in Eastern Iberian Peninsula

by Artemi Cerdà, Jesús Rodrigo-Comino, Tuğrul Yakupoğlu, Turgay Dindaroğlu, Enric Terol, Gaspar Mora-Navarro, Alireza Arabameri, Maja Radziemska, Agata Novara, Ataollah Kavian, Magdalena Daria Vaverková, Sameh Kotb Abd-Elmabod, Hafiz Mohkum Hammad and Ioannis N. Daliakopoulos

Water 2020, 12(6), 1539; https://doi.org/10.3390/w12061539 - 28 May 2020

Cited by 48 | Viewed by 7013

Abstract

There is an urgent need to implement environmentally friendly agriculture management practices to achieve the Sustainable Goals for Development (SDGs) of the United Nations by 2030. Mediterranean agriculture is characterized by intense and millennia-old tillage management and as a consequence degraded soil. No-Tillage [...] Read more.

There is an urgent need to implement environmentally friendly agriculture management practices to achieve the Sustainable Goals for Development (SDGs) of the United Nations by 2030. Mediterranean agriculture is characterized by intense and millennia-old tillage management and as a consequence degraded soil. No-Tillage has been widely examined as a solution for soil degradation but No-Tillage relies more on the application of herbicides that reduce plant cover, which in turn enhances soil erosion. However, No-Tillage with weed cover should be researched to promote organic farming and sustainable agriculture. Therefore, we compare Tillage against No-Tillage using weed cover as an alternative strategy to reduce soil losses in persimmon plantations, both of them under organic farming management. To achieve these goals, two plots were established at “La Canyadeta” experimental station on 25-years old Persimmon plantations, which are managed with Tillage and No-Tillage for 3 years. A survey of the soil cover, soil properties, runoff generation and initial soil losses using rainfall simulation experiments at 55 mm h⁻¹ in 0.25 m² plot was carried out. Soils under Tillage are bare (96.7%) in comparison to the No-Tillage (16.17% bare soil), with similar organic matter (1.71 vs. 1.88%) and with lower bulk densities (1.23 vs. 1.37 g cm³). Tillage induces faster ponding (60 vs. 92 s), runoff (90 vs. 320 s) and runoff outlet (200 vs. 70 s). The runoff discharge was 5.57 times higher in the Tillage plots, 8.64 for sediment concentration and 48.4 for soil losses. We conclude that No-tillage shifted the fate of the tilled field after 3 years with the use of weeds as a soil cover conservation strategy. This immediate effect of No-Tillage under organic farming conditions is very promising to achieve the SDGs. Full article

(This article belongs to the Special Issue Soil Erosion, Soil Desertification and Soil Conservation in Agri-Environment Systems)

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29 pages, 2840 KiB

Open AccessEditor’s ChoiceArticle

Multiple-Line Identification of Socio-Ecological Stressors Affecting Aquatic Ecosystems in Semi-Arid Countries: Implications for Sustainable Management of Fisheries in Sub-Saharan Africa

by Vincent-Paul Sanon, Patrice Toé, Jaime Caballer Revenga, Hamid El Bilali, Laura Janine Hundscheid, Michalina Kulakowska, Piotr Magnuszewski, Paul Meulenbroek, Julie Paillaugue, Jan Sendzimir, Gabriele Slezak, Stefan Vogel and Andreas H. Melcher

Water 2020, 12(6), 1518; https://doi.org/10.3390/w12061518 - 26 May 2020

Cited by 14 | Viewed by 6505

Abstract

Water resources are among the fundamental resources that are the most threatened worldwide by various pressures. This study applied the Driver–Pressure–State–Impact–Response (DPSIR) framework as an innovative tool to better understand the dynamic interlinkages between the different sources of multiple stressors on aquatic ecosystems [...] Read more.

Water resources are among the fundamental resources that are the most threatened worldwide by various pressures. This study applied the Driver–Pressure–State–Impact–Response (DPSIR) framework as an innovative tool to better understand the dynamic interlinkages between the different sources of multiple stressors on aquatic ecosystems in Burkina Faso. The triangulation of evidences from interviews, literature reviews, and strategic simulations shows that several human impacts as well as climate change and its effects (such as the decrease of the water level, and the increase of the surface water temperature) are detrimental to fish productivity, abundance, and average size. Furthermore, the ongoing demographic and nutritional transition is driving cumulative pressures on water and fish resources. In this context, the development of aquaculture could offer alternative livelihoods and help fish stocks in natural ecosystems to recover, thereby reducing fishermen’s vulnerability and easing overfishing pressures. Further, the empowerment of the actors and their participation to reinforce fisheries regulation are required to escape the current “regeneration trap” and to achieve a sustainable management of aquatic ecosystems in Burkina Faso. Full article

(This article belongs to the Special Issue Assessing the Effects of Multiple Stressors on Aquatic Systems across Temporal and Spatial Scales: From Measurement to Management)

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25 pages, 1387 KiB

Open AccessEditor’s ChoiceReview

Organic Fouling in Forward Osmosis: A Comprehensive Review

by Sudesh Yadav, Ibrar Ibrar, Salam Bakly, Daoud Khanafer, Ali Altaee, V. C. Padmanaban, Akshaya Kumar Samal and Alaa H. Hawari

Water 2020, 12(5), 1505; https://doi.org/10.3390/w12051505 - 25 May 2020

Cited by 57 | Viewed by 8255

Abstract

Organic fouling in the forward osmosis process is complex and influenced by different parameters in the forward osmosis such as type of feed and draw solution, operating conditions, and type of membrane. In this article, we reviewed organic fouling in the forward osmosis [...] Read more.

Organic fouling in the forward osmosis process is complex and influenced by different parameters in the forward osmosis such as type of feed and draw solution, operating conditions, and type of membrane. In this article, we reviewed organic fouling in the forward osmosis by focusing on wastewater treatment applications. Model organic foulants used in the forward osmosis literature were highlighted, which were followed by the characteristics of organic foulants when real wastewater was used as feed solution. The various physical and chemical cleaning protocols for the organic fouled membrane are also discussed. The study also highlighted the effective pre-treatment strategies that are effective in reducing the impact of organic fouling on the forward osmosis (FO) membrane. The efficiency of cleaning methods for the removal of organic fouling in the FO process was investigated, including recommendations on future cleaning technologies such as Ultraviolet and Ultrasound. Generally, a combination of physical and chemical cleaning is the best for restoring the water flux in the FO process. Full article

(This article belongs to the Special Issue Novel Forward Osmotic Process for Seawater and Wastewater Treatment)

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17 pages, 4252 KiB

Open AccessEditor’s ChoiceArticle

Utility of Artificial Neural Networks in Modeling Pan Evaporation in Hyper-Arid Climates

by Abdullah A. Alsumaiei

Water 2020, 12(5), 1508; https://doi.org/10.3390/w12051508 - 25 May 2020

Cited by 32 | Viewed by 5346

Abstract

Evaporation is the major water-loss component of the hydrologic cycle and thus requires efficient management. This study aims to model daily pan evaporation rates in hyper-arid climates using artificial neural networks (ANNs). Hyper-arid climates are characterized by harsh environmental conditions where annual precipitation [...] Read more.

Evaporation is the major water-loss component of the hydrologic cycle and thus requires efficient management. This study aims to model daily pan evaporation rates in hyper-arid climates using artificial neural networks (ANNs). Hyper-arid climates are characterized by harsh environmental conditions where annual precipitation rates do not exceed 3% of annual evaporation rates. For the first time, ANNs were applied to model such climatic conditions in the State of Kuwait. Pan evaporation data from 1993–2015 were normalized to a 0–1 range to boost ANN performance and the ANN structure was optimized by testing various meteorological input combinations. Levenberg–Marquardt algorithms were used to train the ANN models. The proposed ANN was satisfactorily efficient in modeling pan evaporation in these hyper-arid climatic conditions. The Nash–Sutcliffe coefficients ranged from 0.405 to 0.755 over the validation period. Mean air temperatures and average wind speeds were identified as meteorological variables that most influenced the ANN performance. A sensitivity analysis showed that the number of hidden layers did not significantly impact the ANN performance. The ANN models demonstrated considerable bias in predicting high pan evaporation rates (>25 mm/day). The proposed modeling method may assist water managers in Kuwait and other hyper-arid regions in establishing resilient water-management plans. Full article

(This article belongs to the Special Issue The Application of Artificial Intelligence in Hydrology)

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14 pages, 10631 KiB

Open AccessFeature PaperEditor’s ChoiceCommunication

Experimental Investigation of Erosion Characteristics of Fine-Grained Cohesive Sediments

by Bommanna Gounder Krishnappan, Mike Stone, Steven J. Granger, Hari Ram Upadhayay, Qiang Tang, Yusheng Zhang and Adrian L. Collins

Water 2020, 12(5), 1511; https://doi.org/10.3390/w12051511 - 25 May 2020

Cited by 8 | Viewed by 3770

Abstract

In this short communication, the erosion process of the fine, cohesive sediment collected from the upper River Taw in South West England was studied in a rotating annular flume located in the National Water Research Institute in Burlington, Ontario, Canada. This study is [...] Read more.

In this short communication, the erosion process of the fine, cohesive sediment collected from the upper River Taw in South West England was studied in a rotating annular flume located in the National Water Research Institute in Burlington, Ontario, Canada. This study is part of a research project that is underway to model the transport of fine sediment and the associated nutrients in that river system. The erosion experimental data show that the critical shear stress for erosion of the upper River Taw sediment is about 0.09 Pa and it did not depend on the age of sediment deposit. The eroded sediment was transported in a flocculated form and the agent of flocculation for the upper River Taw sediment may be due to the presence of fibrils from microorganisms and organic material in the system. The experimental data were analysed using a curve fitting approach of Krone and a mathematical model of cohesive sediment transport in rotating circular flumes developed by Krishnappan. The modelled and measured data were in good agreement. An evaluation of the physical significance of Krone’s fitting coefficients is presented. Variability of the fitting coefficients as a function of bed shear stress and age of sediment deposit indicate the key role these two factors play in the erosion process of fluvial cohesive sediment. Full article

(This article belongs to the Special Issue Environmental Hydraulics Research)

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29 pages, 10243 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Life Cycle of Oil and Gas Fields in the Mississippi River Delta: A Review

by John W. Day, H. C. Clark, Chandong Chang, Rachael Hunter and Charles R. Norman

Water 2020, 12(5), 1492; https://doi.org/10.3390/w12051492 - 23 May 2020

Cited by 43 | Viewed by 10625

Abstract

Oil and gas (O&G) activity has been pervasive in the Mississippi River Delta (MRD). Here we review the life cycle of O&G fields in the MRD focusing on the production history and resulting environmental impacts and show how cumulative impacts affect coastal ecosystems. [...] Read more.

Oil and gas (O&G) activity has been pervasive in the Mississippi River Delta (MRD). Here we review the life cycle of O&G fields in the MRD focusing on the production history and resulting environmental impacts and show how cumulative impacts affect coastal ecosystems. Individual fields can last 40–60 years and most wells are in the final stages of production. Production increased rapidly reaching a peak around 1970 and then declined. Produced water lagged O&G and was generally higher during declining O&G production, making up about 70% of total liquids. Much of the wetland loss in the delta is associated with O&G activities. These have contributed in three major ways to wetland loss including alteration of surface hydrology, induced subsidence due to fluids removal and fault activation, and toxic stress due to spilled oil and produced water. Changes in surface hydrology are related to canal dredging and spoil placement. As canal density increases, the density of natural channels decreases. Interconnected canal networks often lead to saltwater intrusion. Spoil banks block natural overland flow affecting exchange of water, sediments, chemicals, and organisms. Lower wetland productivity and reduced sediment input leads to enhanced surficial subsidence. Spoil banks are not permanent but subside and compact over time and many spoil banks no longer have subaerial expression. Fluid withdrawal from O&G formations leads to induced subsidence and fault activation. Formation pore pressure decreases, which lowers the lateral confining stress acting in the formation due to poroelastic coupling between pore pressure and stress. This promotes normal faulting in an extensional geological environment like the MRD, which causes surface subsidence in the vicinity of the faults. Induced reservoir compaction results in a reduction of reservoir thickness. Induced subsidence occurs in two phases especially when production rate is high. The first phase is compaction of the reservoir itself while the second phase is caused by a slow drainage of pore pressure in bounding shales that induces time-delayed subsidence associated with shale compaction. This second phase can continue for decades, even after most O&G has been produced, resulting in subsidence over much of an oil field that can be greater than surface subsidence due to altered hydrology. Produced water is water brought to the surface during O&G extraction and an estimated 2 million barrels per day were discharged into Louisiana coastal wetlands and waters from nearly 700 sites. This water is a mixture of either liquid or gaseous hydrocarbons, high salinity (up to 300 ppt) water, dissolved and suspended solids such as sand or silt, and injected fluids and additives associated with exploration and production activities and it is toxic to many estuarine organisms including vegetation and fauna. Spilled oil has lethal and sub-lethal effects on a wide range of estuarine organisms. The cumulative effect of alterations in surface hydrology, induced subsidence, and toxins interact such that overall impacts are enhanced. Restoration of coastal wetlands degraded by O&G activities should be informed by these impacts. Full article

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

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12 pages, 4148 KiB

Open AccessEditor’s ChoiceArticle

Study on the Performance Improvement of Axial Flow Pump’s Saddle Zone by Using a Double Inlet Nozzle

by Weidong Cao and Wei Li

Water 2020, 12(5), 1493; https://doi.org/10.3390/w12051493 - 23 May 2020

Cited by 11 | Viewed by 4789

Abstract

The operating range of axial flow pumps is often constrained by the onset of rotating stall. An improved method using a double inlet nozzle to stabilize the performance curve is presented in the current study; a single inlet nozzle and three kinds of [...] Read more.

The operating range of axial flow pumps is often constrained by the onset of rotating stall. An improved method using a double inlet nozzle to stabilize the performance curve is presented in the current study; a single inlet nozzle and three kinds of double inlet nozzle with different rib gap widths at the inlet of axial flow pump impeller were designed. Three dimensional (3D) incompressible flow fields were simulated, and the distributions of turbulence kinetic energy and velocity at different flow rates located at the inlet section, as well as the pressure and streamline in the impeller, were obtained at the same time. The single inlet nozzle scheme and a double inlet nozzle scheme were studied; the experimental and numerical performance results show that although the cross section is partly blocked in the double inlet nozzle, the head and efficiency do not decline at stable operation flow rate. On small flow rate condition, the double inlet nozzle scheme effectively stabilized the head-flow performance, whereby the block induced by the backflow before the impeller was markedly improved by using a double inlet nozzle. It has also been found that the rib gap width impacts the efficiency curve of the axial flow pump. Full article

(This article belongs to the Special Issue Application of Smart Technologies in Water Resources Management)

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20 pages, 4790 KiB

Open AccessEditor’s ChoiceArticle

Accelerating Contaminant Transport Simulation in MT3DMS Using JASMIN-Based Parallel Computing

by Xingwei Liu, Qiulan Zhang and Tangpei Cheng

Water 2020, 12(5), 1480; https://doi.org/10.3390/w12051480 - 22 May 2020

Cited by 2 | Viewed by 4520

Abstract

To overcome the large time and memory consumption problems in large-scale high-resolution contaminant transport simulations, an efficient approach was presented to parallelize the modular three-dimensional transport model for multi-species (MT3DMS) (University of Alabama, Tuscaloosa, AL, USA) program on J adaptive structured meshes applications [...] Read more.

To overcome the large time and memory consumption problems in large-scale high-resolution contaminant transport simulations, an efficient approach was presented to parallelize the modular three-dimensional transport model for multi-species (MT3DMS) (University of Alabama, Tuscaloosa, AL, USA) program on J adaptive structured meshes applications infrastructures (JASMIN). In this approach, a domain decomposition method and a stencil-based method were used to accomplish parallel implementation, while a ghost cell strategy was used for communication. The MODFLOW-MT3DMS coupling mode was optimized to achieve the parallel coupling of flow and contaminant transport. Five types of models were used to verify the correctness and test the parallel performance of the method. The developed parallel program JMT3D (China University of Geosciences (Beijing), Beijing, China) can increase the speed by up to 31.7 times, save memory consumption by 96% with 46 processors, and ensure that the solution accuracy and convergence do not decrease as the number of domains increases. The BiCGSTAB (Bi-conjugate gradient variant algorithm) method required the least amount of time and achieved high speedup in most cases. Coupling the flow and contaminant transport further improved the efficiency of the simulations, with a 33.45 times higher speedup achieved on 46 processors. The AMG (algebraic multigrid) method achieved a good scalability, with an efficiency above 100% on hundreds of processors for the simulation of tens of millions of cells. Full article

(This article belongs to the Special Issue Groundwater and Soil Remediation)

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27 pages, 3838 KiB

Open AccessEditor’s ChoiceArticle

Application of Soft Computing Models with Input Vectors of Snow Cover Area in Addition to Hydro-Climatic Data to Predict the Sediment Loads

by Waqas Ul Hussan, Muhammad Khurram Shahzad, Frank Seidel and Franz Nestmann

Water 2020, 12(5), 1481; https://doi.org/10.3390/w12051481 - 22 May 2020

Cited by 7 | Viewed by 4319

Abstract

The accurate estimate of sediment load is important for management of the river ecosystem, designing of water infrastructures, and planning of reservoir operations. The direct measurement of sediment is the most credible method to estimate the sediments. However, this requires a lot of [...] Read more.

The accurate estimate of sediment load is important for management of the river ecosystem, designing of water infrastructures, and planning of reservoir operations. The direct measurement of sediment is the most credible method to estimate the sediments. However, this requires a lot of time and resources. Because of these two constraints, most often, it is not possible to continuously measure the daily sediments for most of the gauging sites. Nowadays, data-based sediment prediction models are famous for bridging the data gaps in the estimation of sediment loads. In data-driven sediment predictions models, the selection of input vectors is critical in determining the best structure of models for the accurate estimation of sediment yields. In this study, time series inputs of snow cover area, basin effective rainfall, mean basin average temperature, and mean basin evapotranspiration in addition to the flows were assessed for the prediction of sediment loads. The input vectors were assessed with artificial neural network (ANN), adaptive neuro-fuzzy logic inference system with grid partition (ANFIS-GP), adaptive neuro-fuzzy logic inference system with subtractive clustering (ANFIS-SC), adaptive neuro-fuzzy logic inference system with fuzzy c-means clustering (ANFIS-FCM), multiple adaptive regression splines (MARS), and sediment rating curve (SRC) models for the Gilgit River, the tributary of the Indus River in Pakistan. The comparison of different input vectors showed improvements in the prediction of sediments by using the snow cover area in addition to flows, effective rainfall, temperature, and evapotranspiration. Overall, the ANN model performed better than all other models. However, as regards sediment load peak time series, the sediment loads predicted using the ANN, ANFIS-FCM, and MARS models were found to be closer to the measured sediment loads. The ANFIS-FCM performed better in the estimation of peak sediment yields with a relative accuracy of 81.31% in comparison to the ANN and MARS models with 80.17% and 80.16% of relative accuracies, respectively. The developed multiple linear regression equation of all models show an R² value of 0.85 and 0.74 during the training and testing period, respectively. Full article

(This article belongs to the Section Hydrology)

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19 pages, 1540 KiB

Open AccessEditor’s ChoiceArticle

Three-Dimensional Wave-Induced Dynamic Response in Anisotropic Poroelastic Seabed

by Cheng-Jung Hsu and Ching Hung

Water 2020, 12(5), 1465; https://doi.org/10.3390/w12051465 - 21 May 2020

Cited by 6 | Viewed by 2853

Abstract

This paper presents a novel analytical solution, which is developed for investigating three-dimensional wave-induced seabed responses for anisotropic permeability. The analytical solution is based on the assumption of the poroelastic and the

u - p

dynamic form, which considers the inertia force of [...] Read more.

This paper presents a novel analytical solution, which is developed for investigating three-dimensional wave-induced seabed responses for anisotropic permeability. The analytical solution is based on the assumption of the poroelastic and the

u - p

dynamic form, which considers the inertia force of the soil skeleton. In this paper, the problem is regarded as an eigenvalue problem through a first-order ordinary differential equation in matrix form. The problematic eigenvector involved in the solution is dealt with using numerical computation, and a process is proposed to implement the present solution for the desired dynamic response. A verification, which is compared with two existing solutions, demonstrates an agreement with the present solution. The results show that the amplitude profile of seabed response for a shorter wave period varies significantly. A comparison between the anisotropic and transverse isotropic, as well as isotropic permeabilities reveals that the error of vertical effective stress on the seabed bottom can reach

74.8 %

for the isotropic case. For anisotropic permeability, when the wave direction is parallel to the higher horizontal permeability direction, the amplitude profiles of pore pressure and vertical effective stress exhibit the greatest dissipation and increment, respectively. For transverse isotropic permeability, the vertical effective stress is independent of the wave direction, which results in the two horizontal effective stresses on the seabed bottom being identical to each other and independent of the wave direction. Our comprehensive analysis provides insight into the effect of anisotropic permeability on different wave periods and wave directions. Full article

(This article belongs to the Special Issue Wave-structure Interaction Processes in Coastal Engineering)

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23 pages, 7394 KiB

Open AccessEditor’s ChoiceArticle

Heavy Precipitation Systems in Calabria Region (Southern Italy): High-Resolution Observed Rainfall and Large-Scale Atmospheric Pattern Analysis

by Aldo Greco, Davide Luciano De Luca and Elenio Avolio

Water 2020, 12(5), 1468; https://doi.org/10.3390/w12051468 - 21 May 2020

Cited by 23 | Viewed by 5187

Abstract

An in-depth analysis of historical heavy rainfall fields clearly constitutes an important aspect in many related topics: as examples, mesoscale models for early warning systems and the definition of design event scenarios can be improved, with the consequent upgrading in the prediction of [...] Read more.

An in-depth analysis of historical heavy rainfall fields clearly constitutes an important aspect in many related topics: as examples, mesoscale models for early warning systems and the definition of design event scenarios can be improved, with the consequent upgrading in the prediction of induced phenomena (mainly floods and landslides) into specific areas of interest. With this goal, in this work the authors focused on Calabria region (southern Italy) and classified the main precipitation systems through the analysis of selected heavy rainfall events from high resolution rain gauge network time series. Moreover, the authors investigated the relationships among the selected events and the main synoptic atmospheric patterns derived by the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 Reanalysis dataset, in order to assess the possible large-scale scenarios which can induce heavy rainfall events in the study area. The obtained results highlighted: (i) the importance of areal reduction factors, rainfall intensities and amounts in order to discriminate the investigated precipitations systems for the study area; (ii) the crucial role played by the position of the averaged low-pressure areas over the Mediterranean for the synoptic systems, and by low-level temperature for the convective systems. Full article

(This article belongs to the Special Issue Extreme Rainfall and Floods in the Mediterranean Regions)

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15 pages, 2876 KiB

Open AccessEditor’s ChoiceArticle

A Pragmatic Slope-Adjusted Curve Number Model to Reduce Uncertainty in Predicting Flood Runoff from Steep Watersheds

by Muhammad Ajmal, Muhammad Waseem, Dongwook Kim and Tae-Woong Kim

Water 2020, 12(5), 1469; https://doi.org/10.3390/w12051469 - 21 May 2020

Cited by 44 | Viewed by 5651

Abstract

The applicability of the curve number (CN) model to estimate runoff has been a conundrum for years, among other reasons, because it presumes an uncertain fixed initial abstraction coefficient (λ = 0.2), and because choosing the most suitable watershed CN values is still [...] Read more.

The applicability of the curve number (CN) model to estimate runoff has been a conundrum for years, among other reasons, because it presumes an uncertain fixed initial abstraction coefficient (λ = 0.2), and because choosing the most suitable watershed CN values is still debated across the globe. Furthermore, the model is widely applied beyond its originally intended purpose. Accordingly, there is a need for more case-specific adjustments of the CN values, especially in steep-slope watersheds with diverse natural environments. This study scrutinized the λ and watershed slope factor effect in estimating runoff. Our proposed slope-adjusted CN (CN_IIα) model used data from 1779 rainstorm–runoff events from 39 watersheds on the Korean Peninsula (1402 for calibration and 377 for validation), with an average slope varying between 7.50% and 53.53%. To capture the agreement between the observed and estimated runoff, the original CN model and its seven variants were evaluated using the root mean square error (RMSE), Nash–Sutcliffe efficiency (NSE), percent bias (PB), and 1:1 plot. The overall lower RMSE, higher NSE, better PB values, and encouraging 1:1 plot demonstrated good agreement between the observed and estimated runoff by one of the proposed variants of the CN model. This plausible goodness-of-fit was possibly due to setting λ = 0.01 instead of 0.2 or 0.05 and practically sound slope-adjusted CN values to our proposed modifications. For more realistic results, the effects of rainfall and other runoff-producing factors must be incorporated in CN value estimation to accurately reflect the watershed conditions. Full article

(This article belongs to the Special Issue Soil Conservation Service Curve Number (SCS-CN) Method Current Applications, Remaining Challenges, and Future Perspectives)

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20 pages, 12269 KiB

Open AccessEditor’s ChoiceArticle

A Zero-Liquid Discharge Model for a Transient Solar-Powered Desalination System for Greenhouse

by Mohammad Akrami, Alaa H. Salah, Mahdieh Dibaj, Maxime Porcheron, Akbar A. Javadi, Raziyeh Farmani, Hassan E. S. Fath and Abdelazim Negm

Water 2020, 12(5), 1440; https://doi.org/10.3390/w12051440 - 19 May 2020

Cited by 16 | Viewed by 7713

Abstract

The need for sustainable desalination arises from fast-occurring global warming and intensifying droughts due to increasing temperatures, particularly in the Middle East and North African (MENA) regions. Lack of water resources has meant that the countries in these regions have had to desalinate [...] Read more.

The need for sustainable desalination arises from fast-occurring global warming and intensifying droughts due to increasing temperatures, particularly in the Middle East and North African (MENA) regions. Lack of water resources has meant that the countries in these regions have had to desalinate seawater through different sustainable technologies for food supplies and agricultural products. Greenhouses (GH) are used to protect crops from harsh climates, creating a controlled environment requiring less water. In order to have a sustainable resilient GH, a zero-liquid-discharge system (ZLD) was developed by using solar still (SS) desalination techniques, humidification-dehumidification (HDH), and rainwater harvesting. An experiment was designed and carried out by designing and manufacturing a wick type solar still, together with an HDH system, implemented into a GH. Using a pyrometer, the solar intensity was recorded, while the microclimate conditions (temperature and relative humidity) of the GH were also monitored. The GH model was tested in the UK and was shown to be a successful standalone model, providing its water requirements. In the UK, for one solar still with a surface area of 0.72 m², maximum amount of 58 mL of distilled water was achieved per day. In Egypt, a maximum amount of 1090 mL water was collected per day, from each solar still. This difference is mainly due to the differences in the solar radiation intensity and duration in addition to the temperature variance. While dehumidification generated 7 L of distilled water, rainwater harvesting was added as another solution to the greenhouse in the UK, harvested a maximum of 7 L per day from one side (half the area of the greenhouse roof). This helped to compensate for the less distilled water from the solar stills. The results for the developed greenhouses showed how GHs in countries with different weather conditions could be standalone systems for their agricultural water requirement. Full article

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

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12 pages, 246 KiB

Open AccessEditor’s ChoiceReview

The Water Framework Directive and Agricultural Diffuse Pollution: Fighting a Running Battle?

by Mark Wiering, Daan Boezeman and Ann Crabbé

Water 2020, 12(5), 1447; https://doi.org/10.3390/w12051447 - 19 May 2020

Cited by 31 | Viewed by 5715

Abstract

In order to provide a common ground for the Special Issue ‘Water quality and agricultural diffuse pollution in light of the EU Water Framework Directive,’ this review sets out to provide a concise overview of the academic literature on two topics. First, we [...] Read more.

In order to provide a common ground for the Special Issue ‘Water quality and agricultural diffuse pollution in light of the EU Water Framework Directive,’ this review sets out to provide a concise overview of the academic literature on two topics. First, we review the issues in the governance literature on the ‘wicked problem’ of diffuse agricultural sources focussing on three principles: (1) fragmentation and the distribution of power to address diffuse sources, (2) the problem of source-oriented and effect-oriented measures, and (3) contested knowledge for policies for diffuse sources. Second, we briefly sketch the literature on policy instruments and confront that with the scholarly understanding of addressing diffuse agricultural sources under the Water Framework Directive (WFD). Full article

(This article belongs to the Special Issue Water Quality and Agricultural Diffuse Pollution in Light of the EU Water Framework Directive)

52 pages, 1480 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Towards the Implementation of Circular Economy in the Wastewater Sector: Challenges and Opportunities

by Sonia Guerra-Rodríguez, Paula Oulego, Encarnación Rodríguez, Devendra Narain Singh and Jorge Rodríguez-Chueca

Water 2020, 12(5), 1431; https://doi.org/10.3390/w12051431 - 18 May 2020

Cited by 163 | Viewed by 15484

Abstract

The advancement of science has facilitated increase in the human lifespan, reflected in economic and population growth, which unfortunately leads to increased exploitation of resources. This situation entails not only depletion of resources, but also increases environmental pollution, mainly due to atmospheric emissions, [...] Read more.

The advancement of science has facilitated increase in the human lifespan, reflected in economic and population growth, which unfortunately leads to increased exploitation of resources. This situation entails not only depletion of resources, but also increases environmental pollution, mainly due to atmospheric emissions, wastewater effluents, and solid wastes. In this scenario, it is compulsory to adopt a paradigm change, as far as the consumption of resources by the population is concerned, to achieve a circular economy. The recovery and reuse of resources are key points, leading to a decrease in the consumption of raw materials, waste reduction, and improvement of energy efficiency. This is the reason why the concept of the circular economy can be applied in any industrial activity, including the wastewater treatment sector. With this in view, this review manuscript focuses on demonstrating the challenges and opportunities in applying a circular economy in the water sector. For example, reclamation and reuse of wastewater to increase water resources, by paying particular attention to the risks for human health, recovery of nutrients, or highly added-value products (e.g., metals and biomolecules among others), valorisation of sewage sludge, and/or recovery of energy. Being aware of this situation, in the European, Union 18 out of 27 countries are already reusing reclaimed wastewater at some level. Moreover, many wastewater treatment plants have reached energy self-sufficiency, producing up to 150% of their energy requirements. Unfortunately, many of the opportunities presented in this work are far from becoming a reality. Still, the first step is always to become aware of the problem and work on optimizing the solution to make it possible. Full article

(This article belongs to the Special Issue Urban and Industrial Wastewater Disinfection and Decontamination by Advanced Oxidation Processes (AOPs): Current Issues and Future Trends)

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21 pages, 3197 KiB

Open AccessEditor’s ChoiceArticle

Water Resources Management Strategies for Irrigated Agriculture in the Indus Basin of Pakistan

by Muhammad Muzammil, Azlan Zahid and Lutz Breuer

Water 2020, 12(5), 1429; https://doi.org/10.3390/w12051429 - 17 May 2020

Cited by 45 | Viewed by 18110

Abstract

Agriculture of Pakistan relies on the Indus basin, which is facing severe water scarcity conditions. Poor irrigation practices and lack of policy reforms are major threats for water and food security of the country. In this research, alternative water-saving strategies are evaluated through [...] Read more.

Agriculture of Pakistan relies on the Indus basin, which is facing severe water scarcity conditions. Poor irrigation practices and lack of policy reforms are major threats for water and food security of the country. In this research, alternative water-saving strategies are evaluated through a high spatio-temporal water footprint (WF) assessment (1997–2016) for the Punjab and Sindh provinces, which cover an irrigated area of 17 million hectares in the Indus basin of Pakistan. The SPARE:WATER model is used as a spatial decision support tool to calculate the WF and establish alternative management plans for more sustainable water use. The average water consumption (WF_area) is estimated to 182 km³ yr⁻¹, composed of 75% blue water (irrigation water from surface water and groundwater sources), 17% green water (precipitation) and 8% grey water (water used to remove soil salinity or dilute saline irrigation water). Sugarcane, cotton, and rice are highly water-intensive crops, which consume 57% of the annual water use. However, WF_area can be reduced by up to 35% through optimized cropping patterns of the existing crops with the current irrigation settings and even by up to 50% through the combined implementation of optimal cropping patterns and improved irrigation technologies, i.e., sprinkler and drip irrigation. We recommend that the economic impact of these water-saving strategies should be investigated in future studies to inform stakeholders and policymakers to achieve a more sustainable water policy for Pakistan. Full article

(This article belongs to the Special Issue Water Footprint Assessment Research)

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26 pages, 7774 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Coastal Vulnerability Assessment along the North-Eastern Sector of Gozo Island (Malta, Mediterranean Sea)

by Angela Rizzo, Vittoria Vandelli, George Buhagiar, Anton S. Micallef and Mauro Soldati

Water 2020, 12(5), 1405; https://doi.org/10.3390/w12051405 - 15 May 2020

Cited by 46 | Viewed by 7770

Abstract

The coastal landscape of the Maltese Islands is the result of long-term evolution, influenced by tectonics, geomorphological processes, and sea level oscillations. Due to their geological setting, the islands are particularly prone to marine-related and gravity-induced processes, exacerbated by climate change. This study [...] Read more.

The coastal landscape of the Maltese Islands is the result of long-term evolution, influenced by tectonics, geomorphological processes, and sea level oscillations. Due to their geological setting, the islands are particularly prone to marine-related and gravity-induced processes, exacerbated by climate change. This study aligns different concepts into a relatively concise and expedient methodology for overall coastal vulnerability assessment, taking the NE sector of Gozo Island as a test case. Geomorphological investigation, integrated with analysis of marine geophysical data, enabled characterization of coastal dynamics, identifying this stretch of coast as being potentially hazardous. The study area features a high economic value derived from tourist and mining activities and natural protected areas, that altogether not only make coastal vulnerability a major concern but also the task of assessing it complex. Before introducing the methodology proposed for overall vulnerability assessment, an in-depth revision of the vulnerability concept is provided. The evaluation was carried out by using a set of key indicators related to local land use, anthropic and natural assets, economic activities, and social issues. Results show that the most critical areas are located east of Marsalforn including Ramla Bay, an important tourist attraction hosting the largest sandy beach in Gozo. The method combines physical exposure and social vulnerability into an overall index. It proves to be cost effective in data management and processing and is suitable for the identification and assessment of overall vulnerability of coastal areas to consequences of climate- and marine-related processes, such as coastal erosion, landslides and sea level rise. Full article

(This article belongs to the Special Issue Landscapes and Landforms of Terrestrial and Marine Areas)

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