Water

12 pages, 219 KiB

Open AccessArticle

Landlords’ and Compound Managers’ Role in Improving and Sustaining Shared Latrines in Three Dhaka City Slums

by Farzana Yeasmin, Mahbubur Rahman, Stephen P Luby, Jyoti Bhushan Das, Farzana Begum, Ronald E Saxton, Fosiul A Nizame, Sharon T Hwang, Mahbub-Ul Alam, Md. Khobair Hossain, Dalia Yeasmin, Leanne Unicomb and Peter J Winch

Water 2020, 12(7), 2073; https://doi.org/10.3390/w12072073 - 21 Jul 2020

Cited by 3 | Viewed by 3901

Abstract

(1) Background: Residents of Dhaka slums frequently lack clean and functional shared latrines. We explored the role of landlords and compound managers in promoting latrine cleanliness in the intervention arm of a randomized trial; (2) Methods: We conducted focus group discussions, key informant [...] Read more.

(1) Background: Residents of Dhaka slums frequently lack clean and functional shared latrines. We explored the role of landlords and compound managers in promoting latrine cleanliness in the intervention arm of a randomized trial; (2) Methods: We conducted focus group discussions, key informant interviews, and in-depth interviews with community health promoters, landlords, and compound managers to better understand the decision-making process, barriers to contributing to sanitation, and cleanliness of shared latrines. (3) Results: Landlords’ and compound managers’ engagement in promoting clean and functional latrines depended, in part, on their own proximity to the properties they own and manage. The compound managers played a leadership role through engagement with health promoters, oversight of implementation of a cleaning schedule, and support for installation and maintenance of sanitation hardware, resulting in improved sanitation practices; (4) Conclusions: Interventions in slums in Bangladesh should consider engaging landlords and compound managers in efforts to bring about structural and organizational changes to support the adoption of improved water, sanitation, and hygiene practices. Full article

(This article belongs to the Section Urban Water Management)

22 pages, 7231 KiB

Open AccessArticle

The Impact of Biophysical Processes on Sediment Transport in the Wax Lake Delta (Louisiana, USA)

by Courtney Elliton, Kehui Xu and Victor H. Rivera-Monroy

Water 2020, 12(7), 2072; https://doi.org/10.3390/w12072072 - 21 Jul 2020

Cited by 10 | Viewed by 3569

Abstract

Sediment transport in coastal regions is regulated by the interaction of river discharge, wind, waves, and tides, yet the role of vegetation in this interaction is not well understood. Here, we evaluated these variables using multiple acoustic and optical sensors deployed for 30–60 [...] Read more.

Sediment transport in coastal regions is regulated by the interaction of river discharge, wind, waves, and tides, yet the role of vegetation in this interaction is not well understood. Here, we evaluated these variables using multiple acoustic and optical sensors deployed for 30–60 days in spring and summer/fall 2015 at upstream and downstream stations in Mike Island, a deltaic island within the Wax Lake Delta, LA, USA. During a flooding stage, semidiurnal and diurnal tidal impact was minimal on an adjacent river channel, but significant in Mike Island where vegetation biomass was low and wave influence was greater downstream. During summer/fall, a “vegetated channel” constricted the water flow, decreasing current speeds from ~13 cm/s upstream to nearly zero downstream. Synchrony between the upstream and downstream water levels in spring (R² = 0.91) decreased in summer/fall (R² = 0.84) due to dense vegetation, which also reduced the wave heights from 3–20 cm (spring) to nearly 0 cm (summer/fall). Spatial and temporal differences in total inorganic nitrogen and orthophosphate concentrations in the overlying and sediment porewater were evident as result of vegetation growth and expansion during summer/fall. This study provides key hourly/daily data and information needed to improve the parameterization of biophysical models in coastal wetland restoration projects. Full article

(This article belongs to the Special Issue Observation and Numerical Modeling of Sediment Transport in Coastal Areas)

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16 pages, 1892 KiB

Open AccessEditor’s ChoiceArticle

Bioremediation of Aquaculture Wastewater with Algal-Bacterial Biofilm Combined with the Production of Selenium Rich Biofertilizer

by Wei Han, Yufeng Mao, Yunpeng Wei, Peng Shang and Xu Zhou

Water 2020, 12(7), 2071; https://doi.org/10.3390/w12072071 - 21 Jul 2020

Cited by 30 | Viewed by 5739

Abstract

The discharge of aquaculture wastewater and the excessive selenium in aquaculture effluent caused by selenium addition to aquatic feed are posing a serious risk for the marine environment. In this study, batch tests were carried out to investigate the feasibility of utilizing algal–bacterial [...] Read more.

The discharge of aquaculture wastewater and the excessive selenium in aquaculture effluent caused by selenium addition to aquatic feed are posing a serious risk for the marine environment. In this study, batch tests were carried out to investigate the feasibility of utilizing algal–bacterial biofilm for the treatment of selenium-rich aquaculture wastewater. The effects of four different types of commercial biofilm carriers on the attached growth of biofilms and the contaminant removal capacity were examined. The braided cotton biofilm carrier had the best performance on biofilm growth, while in an exponential growth period the dry weight density of the biofilm was above 2.0 g L⁻¹. By utilizing the braided cotton carrier with a hydraulic retention time (HRT) of 6 days, the removal rate of N and P from the raw aquaculture wastewater was 88.5 ± 6.2% and 99.8 ± 0.2%, respectively. After that, the effects of different initial wastewater load ratios (IWLR) and HRT on the effluent quality of the treatment process were studied. The decrease in IWLR and the extension of HRT could improve the treatment performance. The effluent N, P and Se concentrations in the group with 50% IWLR and 6-day HRT were 0.75 ± 0.10 mg L⁻¹, 0.015 ± 0.02 mg L⁻¹, 35.2 ± 3.2 μg L⁻¹, respectively, indicating an effective removal of the main contaminants. The algal–bacterial biofilm harvested from the batch test was rich in N, P and Se, where the Se content was 21.8 ± 3.4 mg kg⁻¹, which has the potential to be used as an Se-rich biofertilizer. Full article

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

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31 pages, 15847 KiB

Open AccessCase Report

Flood Hydraulic Analyses: A Case Study of Amik Plain, Turkey

by Fatih Üneş, Yunus Ziya Kaya, Hakan Varçin, Mustafa Demirci, Bestami Taşar and Martina Zelenakova

Water 2020, 12(7), 2070; https://doi.org/10.3390/w12072070 - 21 Jul 2020

Cited by 3 | Viewed by 4276

Abstract

In recent years, significant flood events have occurred in various parts of the world. The most important reasons for these events are global warming and consequent imbalances in climate and rainfall regimes. Many studies are performed to prevent the loss of life and [...] Read more.

In recent years, significant flood events have occurred in various parts of the world. The most important reasons for these events are global warming and consequent imbalances in climate and rainfall regimes. Many studies are performed to prevent the loss of life and property caused by floods. Many methods have been developed to predict future floods and possible affected areas. Developing computer and numerical calculation methods gives opportunities to make simulations of flood hazards. One of the affected areas, which is also one of the world’s first residential districts at Hatay in Turkey, is the Amik Plain. In this study, the floods on the Amik Plain in Hatay province are analyzed. Hatay airport was also affected during floods since 2012 and serious material damage occurred. For this purpose, Google Earth Pro software was used to obtain maps of the basin where the airport is located and the rivers it contains. Afterwards, Hydrologic Engineering Center’s River Analysis System module (HEC-RAS) was used for the hydraulic and hydrological definitions of the river basin. The results of numerical models are presented as simulated maps. Full article

(This article belongs to the Special Issue Urban Rainwater and Flood Management)

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17 pages, 3949 KiB

Open AccessArticle

Evaluation of Reservoir-Induced Hydrological Alterations and Ecological Flow Based on Multi-Indicators

by Mingqian Li, Xiujuan Liang, Changlai Xiao, Xuezhu Zhang, Guiyang Li, Hongying Li and Wenhan Jang

Water 2020, 12(7), 2069; https://doi.org/10.3390/w12072069 - 21 Jul 2020

Cited by 15 | Viewed by 2776

Abstract

Although they fulfill various needs of human beings, reservoirs also cause hydrological regime variation in the downstream regions, thus affecting ecological diversity. Therefore, studying the reservoir-induced hydrological alterations and ecological effects is of great significance, as it could guide the regulation of the [...] Read more.

Although they fulfill various needs of human beings, reservoirs also cause hydrological regime variation in the downstream regions, thus affecting ecological diversity. Therefore, studying the reservoir-induced hydrological alterations and ecological effects is of great significance, as it could guide the regulation of the reservoir to protect the river ecology. In this study, taking the Taizi River as an example, the impact of a reservoir on hydrological alteration and ecological diversity was comprehensively evaluated through eco-flow indicators based on the flow duration curve and multiple hydrological indicators. The results reveal that: (1) Ecological indicators can be used to analyze the annual and seasonal changes in the streamflow after the construction of the reservoir. The high-flow values and frequency decrease after the construction of the reservoir, especially in the autumn, while the low-flow component values increase significantly, especially in spring and summer. (2) The main influencing factors of the ecological indicators can be reflected by the relationship with precipitation, as the annual ecosurplus is not significantly affected by the reservoir, while the ecodeficit is greatly affected, and the seasonal ecological indicators (especially in spring and summer) are greatly affected by the reservoir. (3) The indicators of hydrologic alteration (IHA) show significant changes after the construction of the reservoir and are consistent with the changes in the eco-flow indicators; the change in the Shannon index indicates that the ecological diversity reduced after construction of the reservoir. It is controlled by the reservoir, and a new equilibrium state appears. (4) The eco-flow indicators have a good correlation with the 32 IHAs; they can reflect the change information of most IHAs and can avoid statistical redundancy. Full article

(This article belongs to the Section Hydrology)

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Graphical abstract

23 pages, 13283 KiB

Open AccessArticle

Assessing the Impact of Chemical Loads from Agriculture Holdings on the Puck Bay Environment with the High-Resolution Ecosystem Model of the Puck Bay, Southern Baltic Sea

by Dawid Dybowski, Maciej Janecki, Artur Nowicki and Lidia Anita Dzierzbicka-Glowacka

Water 2020, 12(7), 2068; https://doi.org/10.3390/w12072068 - 21 Jul 2020

Cited by 6 | Viewed by 2540

Abstract

This paper describes the ecohydrodynamic predictive model EcoPuckBay—the ecosystem part—for assessing the state of the Puck Bay coastal environment and its ecosystem. We coupled the EcoPuckBay model with the land water flow models (Soil and Water Assessment Tool (SWAT) for surface water and [...] Read more.

This paper describes the ecohydrodynamic predictive model EcoPuckBay—the ecosystem part—for assessing the state of the Puck Bay coastal environment and its ecosystem. We coupled the EcoPuckBay model with the land water flow models (Soil and Water Assessment Tool (SWAT) for surface water and Modflow for groundwater). To evaluate the quality of the results obtained from the EcoPuckBay model, a set of basic statistical measures for dissolved oxygen, chlorophyll-a, nitrates, and phosphates were calculated, such as mean, Pearson correlation coefficient (r), root-mean-square-error (RMSE), and standard deviation (STD). The analysis presented in this paper shows that the EcoPuckBay model produces reliable results. In addition, we developed a nutrient spread module to show the impact of agricultural activity on the waters of the Puck Bay. The EcoPuckBay model is also available in operational mode where users can access 60-h forecasts via the website of the WaterPUCK Project through the “Products” tab. Full article

(This article belongs to the Special Issue Modeling and Analysis of Hydrodynamics, Water Quality and Ice Phenomena for Lagoons and Shallow Bays)

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14 pages, 3389 KiB

Open AccessArticle

Diatom Taxonomic Composition as a Biological Indicator of the Ecological Health and Status of a River Basin under Agricultural Influence

by Xinxin Lu, Yan Liu and Yawen Fan

Water 2020, 12(7), 2067; https://doi.org/10.3390/w12072067 - 21 Jul 2020

Cited by 14 | Viewed by 3132

Abstract

The Lalin River Basin (LLRB) is a major drainage basin in northeastern China, that has been significantly influenced by agricultural activities. This study focused on exploring diatom taxonomic composition linked to environmental factors at the taxonomic levels of genus and species during ice-covered [...] Read more.

The Lalin River Basin (LLRB) is a major drainage basin in northeastern China, that has been significantly influenced by agricultural activities. This study focused on exploring diatom taxonomic composition linked to environmental factors at the taxonomic levels of genus and species during ice-covered periods. Nine sampling stations were divided into three groups based on trophic state index (TSI). hierarchical cluster analysis (HCA) and redundancy analysis (RDA) were performed to identify diatom distribution patterns and their relationships to environmental factors. Diatom richness, composition and distribution were analyzed at the levels of genus and species. Our results showed the epipelagic diatom Melosira varians was very abundant at most stations. Benthic diatoms Achnanthidium minutissimum, Encyonema minutum and Gomphonema parvulum were dominant in group-3, which had the highest trophic states. HCA showed the similarity of diatom taxonomic composition spatial distribution patterns between genus and species levels. RDA revealed that the key factors related to genus level distributions are COD, TP and EC, while TP was the key factor in structuring diatom taxonomic composition at the level of species. These results suggest identification of diatoms at genus level can be used as a potential indicator to assess ecological health status of agricultural-influenced rivers during ice cover periods. Further research is necessary to explore the utility of genus level diatom composition as a biological indicator in rivers. Full article

(This article belongs to the Special Issue Freshwater Biophysical Ecosystem Health)

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25 pages, 3365 KiB

Open AccessArticle

Trophic Responses of the Asian Reservoir to Long-Term Seasonal and Interannual Dynamic Monsoon

by Md Mamun, Ji Yoon Kim and Kwang-Guk An

Water 2020, 12(7), 2066; https://doi.org/10.3390/w12072066 - 21 Jul 2020

Cited by 15 | Viewed by 3350

Abstract

The main objectives of the study were to determine the trophic response of the temperate reservoir to seasonal and interannual variabilities of monsoon inorganic solids and nutrients along the gradients of the morphologically complex Asian reservoir using long-term datasets between 2000–2018. Nutrient regime [...] Read more.

The main objectives of the study were to determine the trophic response of the temperate reservoir to seasonal and interannual variabilities of monsoon inorganic solids and nutrients along the gradients of the morphologically complex Asian reservoir using long-term datasets between 2000–2018. Nutrient regime (total nitrogen—TN, total phosphorus—TP), total suspended solids (TSS), and chlorophyll-a (CHL-a) were primarily affected by an intensity of summer monsoon and the longitudinal structure of riverine (Rz), transitional (Tz), and lacustrine (Lz) zone. The reservoir is a nitrogen-rich system and the phosphorus content of the water was relatively low, and it had low mean N:P ratios (<40), implying a P-limiting system. The Lz was a highly P-limited zone in comparison to Rz and Tz zone during both drought (2015) and flood year (2011). The TP content was higher in the mainstem (S3) than the embankment (S4 and S6) of the reservoir due to the monsoon river inputs of the nutrients. Nonparametric Mann–Kendall tests indicated that TP decreased over the long-term years in the Rz, while it did not show any trend in Tz, Lz, IT1, and IT2. TN showed an increasing trend in Rz, Tz, Lz, and IT2 except for IT1. The empirical regression model for chlorophyll nutrients showed that CHL-a had a strong positive relationship with TP (R² = 0.67, p < 0.01) than TN (R² = 0.06, p < 0.01), supporting the view that algal growth in lentic systems responds to TP enrichment and TP may provide a reliable basis for predicting algal biomass. The seasonality of CHL-a and TP showed a monomodal pattern and indicates that summer TP influences summer algal growth in Tz, Lz, and IT2. The water clarity (SD) of the reservoir was significantly (p < 0.01) influenced by TP (R² = 0.62), TSS (R² = 0.67), and CHL-a (R² = 0.68) rather than TN (R² = 0.10). The non-algal light attenuation coefficient (K_na) was determined mainly by suspended solids and the monsoon hydrology. The trophic state was much higher when assessments were based on TSI (CHL-a) than on TSI (TP) and TSI (SD). TSI (CHL-a) indicated the eutrophic state of the reservoirs except for the zone of Lz during the premonsoon season. Analysis of trophic state index deviation (TSID) suggested that the blue-green algae dominated the algal community, and the effects of non-algal turbidity and zooplankton grazing were minor in the reservoir. Full article

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

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14 pages, 3369 KiB

Open AccessArticle

The Synthesis of PbS NPs and Biosorption of Pb(II) by Shinella Zoogloeoides PQ7 in Aqueous Conditions

by Wei Zhang and Yili Huang

Water 2020, 12(7), 2065; https://doi.org/10.3390/w12072065 - 21 Jul 2020

Cited by 12 | Viewed by 2927

Abstract

Increasing heavy metal pollution in water continues to endanger human health. The genus Shinella has potential for heavy metal bioremediation but has rarely been studied. In this study, we report that Shinella zoogloeoides PQ7 turns black in the presence of lead ions. Transmission [...] Read more.

Increasing heavy metal pollution in water continues to endanger human health. The genus Shinella has potential for heavy metal bioremediation but has rarely been studied. In this study, we report that Shinella zoogloeoides PQ7 turns black in the presence of lead ions. Transmission electron microscopy (TEM), Scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) indicated that PbS nanoparticles (NPs) were synthesized by PQ7. Moreover, PQ7 was used as a biosorbent to remove Pb(II) from aqueous solutions. Biosorption performance was evaluated in terms of contact time, pH, biomass dosage and initial Pb(II) concentration. The equilibrium and kinetic data were consistent with the Freundlich isotherm model (R² = 0.986) and pseudo-second-order model (R² = 0.977), respectively. The maximum (q_max) Pb(II) adsorption reached 222.22 mg/g, which was higher than that of other bacteria reported in previous literature. SEM–EDS, XRD and Fourier transform infrared (FTIR) analyses also confirmed the adsorption of Pb(II) by the PQ7 cells. In conclusion, PQ7 is a promising strain in removing and recovering Pb(II) from wastewater. Full article

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

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30 pages, 18594 KiB

Open AccessArticle

Comparison of Uranium Isotopes and Classical Geochemical Tracers in Karst Aquifer of Ljubljanica River catchment (Slovenia)

by Leja Rovan, Sonja Lojen, Tea Zuliani, Tjaša Kanduč, Metka Petrič, Barbara Horvat, Simon Rusjan and Marko Štrok

Water 2020, 12(7), 2064; https://doi.org/10.3390/w12072064 - 21 Jul 2020

Cited by 8 | Viewed by 4402

Abstract

The karst aquifer of the Ljubljanica River catchment, which has numerous springs and sinks, presents an interesting environment for studying hydrogeological processes. This study aims to explore the behavior of U isotopes and to evaluate their use as tracers of hydrogeochemical processes as [...] Read more.

The karst aquifer of the Ljubljanica River catchment, which has numerous springs and sinks, presents an interesting environment for studying hydrogeological processes. This study aims to explore the behavior of U isotopes and to evaluate their use as tracers of hydrogeochemical processes as an alternative to classical geochemical tracers (i.e., physicochemical parameters, elemental ratios, and alkalinity) involved in water–rock interactions and water flow in this karst water system. Basic hydrochemical parameters, as well as the spatiotemporal variations of total U concentrations, ²³⁴U/²³⁸U activity ratios, and δ²³⁸U values, were monitored in water samples from springs and sinks under different hydrological conditions. The bedrock as the source of dissolved and detrital U was also analyzed. Multi-collector inductively couple plasma-mass spectrometry results reveal variations of the ²³⁴U/²³⁸U activity ratios, which are consistently negatively correlated with the discharge at most analyzed sites. Large ²³⁸U/²³⁵U isotope fractionation occurred during bedrock weathering, and the large variability of the measured δ²³⁸U values is seemingly unrelated to the lithological characteristics of the bedrock or discharge. Our results confirm that ²³⁴U/²³⁸U activity ratios in water can be used as a tracer for studying changes in groundwater flows and the mixing of waters of different origins under different hydrological conditions. Full article

(This article belongs to the Section Hydrology)

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11 pages, 2630 KiB

Open AccessArticle

Particle Tracking Using Dynamic Water-Level Data

by Yuan Gao

Water 2020, 12(7), 2063; https://doi.org/10.3390/w12072063 - 21 Jul 2020

Cited by 3 | Viewed by 2320

Abstract

The movement of fluid particles about historic subsurface releases is often governed by dynamic subsurface water levels. Motivations for tracking the movement of fluid particles include tracking the fate of subsurface contaminants and resolving the fate of water stored in subsurface aquifers. This [...] Read more.

The movement of fluid particles about historic subsurface releases is often governed by dynamic subsurface water levels. Motivations for tracking the movement of fluid particles include tracking the fate of subsurface contaminants and resolving the fate of water stored in subsurface aquifers. This study provides a novel method for predicting the movement of subsurface particles relying on dynamic water-level data derived from continuously recording pressure transducers. At least three wells are needed to measure water levels which are used to determine the plain of the water table. Based on Darcy’s law, particle flow pathlines at the study site are obtained using the slope of the water table. The results show that hydrologic conditions, e.g., seasonal transpiration and precipitation, influence local groundwater flow. The changes of water level in short periods caused by the hydrologic variations made the hydraulic gradient diversify considerably, thus altering the direction of groundwater flow. Although a range of groundwater flow direction and gradient with time can be observed by an initial review of water levels in rose charts, the net groundwater flow at all field sites is largely constant in one direction which is driven by the gradients with higher magnitude. Full article

(This article belongs to the Section Hydrology)

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Graphical abstract

18 pages, 5171 KiB

Open AccessArticle

Recent Increase of Flood Frequency in the Ionian Belt of Basilicata Region, Southern Italy: Human or Climatic Changes?

by Mario Bentivenga, Salvatore Ivo Giano and Marco Piccarreta

Water 2020, 12(7), 2062; https://doi.org/10.3390/w12072062 - 21 Jul 2020

Cited by 21 | Viewed by 3755

Abstract

The Ionian coast of the Basilicata region, southern Italy, is characterized by a remarkable archaeological heritage, valuable crops, and national and international tourism, contributing significantly to the regional economy. In the last two decades, the area has been affected by the heavy recurrence [...] Read more.

The Ionian coast of the Basilicata region, southern Italy, is characterized by a remarkable archaeological heritage, valuable crops, and national and international tourism, contributing significantly to the regional economy. In the last two decades, the area has been affected by the heavy recurrence of flooding events, which caused significant damage to agriculture, tourist infrastructure, and archaeological heritage. Both qualitative and quantitative analyses of pluviometric, hydrometric, and erosion/deposition dynamics of main rivers have been carried out in order to investigate the role played by natural factors, climate changes, and human activity. The results show that flooding events in the Metaponto plain were certainly caused by extreme rainy events, but man has also played an important role. The Metaponto plain has been involved in a reclamation consisting of the building of an extensive channel network, which provided better land cultivation, easy access to the beaches, and archaeological heritage protection. The human impact related to the absence of channel cleaning has proved to be the most relevant factor that greatly amplified the effects of low-intensity rainfall events, thus triggering flooding events. Full article

(This article belongs to the Special Issue Fluvial Geomorphology and River Management)

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15 pages, 286 KiB

Open AccessReview

Biocontrol of Phytopathogens under Aquaponics Systems

by Tomás Rivas-García, Ramsés Ramón González-Estrada, Roberto Gregorio Chiquito-Contreras, Juan José Reyes-Pérez, Uriel González-Salas, Luis Guillermo Hernández-Montiel and Bernardo Murillo-Amador

Water 2020, 12(7), 2061; https://doi.org/10.3390/w12072061 - 21 Jul 2020

Cited by 10 | Viewed by 5951

Abstract

Aquaponics is an alternative method of food production that confers advantages of biological and economic resource preservations. Nonetheless, one of the main difficulties related to aquaponics systems could be the outbreak and dissemination of pathogens. Conventional treatments need to be administrated carefully because [...] Read more.

Aquaponics is an alternative method of food production that confers advantages of biological and economic resource preservations. Nonetheless, one of the main difficulties related to aquaponics systems could be the outbreak and dissemination of pathogens. Conventional treatments need to be administrated carefully because they could be harmful to human, fish, plants and beneficial microorganisms. Aquaponics practitioners are relatively helpless against plant diseases when they occur, especially in the case of root pathogens. Biological control agents (BCAs) may be an effective alternative to chemical inputs for dealing with pathogens of plants under aquaponics systems. Research of BCAs on aquaponics systems is limited, but there are numerous publications on the use of BCAs to control plant pathogens under soilless systems which confirm its potential use on aquaponics systems. The present review summarized the principal plant pathogens, the conventional and alternative BCA treatments on aquaponics systems, while considering related research on aquaculture and soilless systems (i.e., hydroponic) for its applicability to aquaponics and future perspectives related to biological control. Finally, we emphasized the case that aquaponics systems provide relatively untapped potential for research on plant biological control agents. Biological control has the potential to reduce the perturbation effects of conventional treatments on microbial communities, fish and plant physiology, and the whole function of the aquaponics system. Full article

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

18 pages, 1670 KiB

Open AccessArticle

Assessment of the Urban Water Security in a Severe Water Stress Area–Application to Palestinian Cities

by Samah Jabari, Isam Shahrour and Jamal El Khattabi

Water 2020, 12(7), 2060; https://doi.org/10.3390/w12072060 - 20 Jul 2020

Cited by 9 | Viewed by 3961

Abstract

This paper presents an assessment of the urban water security in a severe water stress area using a semi-quantitative risk-based approach. Water security indicators are selected according to the recommendations of international institutions, the literature review and the opinion of a panel of [...] Read more.

This paper presents an assessment of the urban water security in a severe water stress area using a semi-quantitative risk-based approach. Water security indicators are selected according to the recommendations of international institutions, the literature review and the opinion of a panel of water experts. Selected indicators cover three fields: water resources, water services and water governance. The field of water resources is described by indicators related to the water resources availability, annual precipitation and the ratio of treated water, while the water services field is described by indicators related to the water service coverage, water losses and the continuity of water supply. Water governance includes three indicators: role and responsibility, access to water information and stakeholder engagement. Water security assessment is conducted in three stages: (i) data collection for five Palestinian cities in the West Bank of Jordan, (ii) determination of the risk score for each indicator using collected data and an expert’s opinion, (iii) determination of the global water security score and water security index using the matrix risk assessment and the wise weight assessment ratio analysis (SWARA) methods. Results show that water risk is ranked as extreme for all cities. Risk related to water resources is a major contributor to global risk, followed by water governance. Full article

(This article belongs to the Section Urban Water Management)

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26 pages, 410 KiB

Open AccessReview

Lagoon Resident Fish Species of Conservation Interest According to the Habitat Directive (92/43/CEE): A Review on Their Potential Use as Ecological Indicator Species

by Chiara Facca, Francesco Cavraro, Piero Franzoi and Stefano Malavasi

Water 2020, 12(7), 2059; https://doi.org/10.3390/w12072059 - 20 Jul 2020

Cited by 20 | Viewed by 4453

Abstract

Transitional waters are fragile ecosystems with high ecological, social and economic values, that undergo numerous threats. According to the information provided by European Member States in the framework of the European Directive 92/43/EEC (Habitat Directive), the main threat to these ecosystems is represented [...] Read more.

Transitional waters are fragile ecosystems with high ecological, social and economic values, that undergo numerous threats. According to the information provided by European Member States in the framework of the European Directive 92/43/EEC (Habitat Directive), the main threat to these ecosystems is represented by morphological and hydrological changes. The present work focuses on six lagoon fish species included in the Habitat Directive annex II (species requiring conservation measures: Aphanius fasciatus, A. iberus, Knipowitschia panizzae, Ninnigobius canestrinii, Valencia hispanica and V. letourneuxi) that spend their entire life cycle in the Mediterranean priority habitat 1150* “Coastal lagoons”. The overview of the current scientific literature allowed us to highlight how the presence and abundance of these species may provide important indications on the conservation status of coastal lagoon habitats. In fact, their occurrence, distribution and biology depend on the presence of peculiar structures, such as salt marshes, small channels, isolated pools and oligohaline areas. Coastal lagoon fragmentation and habitat loss have led to a significant reduction in genetic diversity or local population extinction. Although Aphanius and gobies have been shown to survive in eutrophic environments, it is clear that they cannot complete their life cycle without salt marshes (mainly Aphanius) and wetland areas (mainly gobies). Full article

(This article belongs to the Special Issue Ecological Status Assessment of Transitional Waters)

16 pages, 2391 KiB

Open AccessEditor’s ChoiceArticle

Shift Detection in Hydrological Regimes and Pluriannual Low-Frequency Streamflow Forecasting Using the Hidden Markov Model

by Larissa Zaira Rafael Rolim and Francisco de Assis de Souza Filho

Water 2020, 12(7), 2058; https://doi.org/10.3390/w12072058 - 20 Jul 2020

Cited by 10 | Viewed by 2750

Abstract

Improved water resource management relies on accurate analyses of the past dynamics of hydrological variables. The presence of low-frequency structures in hydrologic time series is an important feature. It can modify the probability of extreme events occurring in different time scales, which makes [...] Read more.

Improved water resource management relies on accurate analyses of the past dynamics of hydrological variables. The presence of low-frequency structures in hydrologic time series is an important feature. It can modify the probability of extreme events occurring in different time scales, which makes the risk associated with extreme events dynamic, changing from one decade to another. This article proposes a methodology capable of dynamically detecting and predicting low-frequency streamflow (16–32 years), which presented significance in the wavelet power spectrum. The Standardized Runoff Index (SRI), the Pruned Exact Linear Time (PELT) algorithm, the breaks for additive seasonal and trend (BFAST) method, and the hidden Markov model (HMM) were used to identify the shifts in low frequency. The HMM was also used to forecast the low frequency. As part of the results, the regime shifts detected by the BFAST approach are not entirely consistent with results from the other methods. A common shift occurs in the mid-1980s and can be attributed to the construction of the reservoir. Climate variability modulates the streamflow low-frequency variability, and anthropogenic activities and climate change can modify this modulation. The identification of shifts reveals the impact of low frequency in the streamflow time series, showing that the low-frequency variability conditions the flows of a given year. Full article

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

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20 pages, 27702 KiB

Open AccessArticle

Debris Flow Susceptibility Assessment Using the Integrated Random Forest Based Steady-State Infinite Slope Method: A Case Study in Changbai Mountain, China

by Alu Si, Jiquan Zhang, Yichen Zhang, Emmanuel Kazuva, Zhenhua Dong, Yongbin Bao and Guangzhi Rong

Water 2020, 12(7), 2057; https://doi.org/10.3390/w12072057 - 20 Jul 2020

Cited by 8 | Viewed by 3219

Abstract

Debris flow events often pose significant damage and are a threat to infrastructure and even livelihoods. Recent studies have mainly focused on determining the susceptibility of debris flow using deterministic or heuristic/probabilistic models. However, each type of model has its own significant advantages [...] Read more.

Debris flow events often pose significant damage and are a threat to infrastructure and even livelihoods. Recent studies have mainly focused on determining the susceptibility of debris flow using deterministic or heuristic/probabilistic models. However, each type of model has its own significant advantages with some irreparable disadvantages. The random forest model, which is sensitive to the region where the terrain conditions are suitable for the occurrence of debris flow, was applied along with the steady-state infinite slope method, which is capable of describing the initiation mechanism of debris flow. In this manner, a random-forest-based steady-state infinite slope method was used to conduct susceptibility assessment of debris-flow at Changbai mountain area. Results showed that the assessment accuracy of the proposed random-forest-based steady-state infinite slope method reached 90.88%; however, the accuracy of just the random forest model or steady-state infinite slope method was only 88.48% or 60.45%, respectively. Compared with the single-model assessment results, the assessment accuracy of the proposed method improved by 2.4% and 30.43%, respectively. Meanwhile, the debris-flow-prone area of the proposed method was reduced. The random-forest-based steady-state infinite slope method inherited the excellent diagnostic performance of the random-forest models in the region where the debris flow disaster already occurred; meanwhile, this method further refined the debris-flow-prone area from the suitable terrain area based on physico-mechanical properties; thus, the performance of this method was better than those of the other two models. Full article

(This article belongs to the Special Issue Debris Flows Research: Hazard and Risk Assessments)

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7 pages, 180 KiB

Open AccessEditorial

Editorial—Using Applied Economics to Study Participatory Irrigation Institutions and their Impact in South Asia

by Lin Crase

Water 2020, 12(7), 2056; https://doi.org/10.3390/w12072056 - 20 Jul 2020

Cited by 1 | Viewed by 1830

Abstract

For many decades, participatory approaches, with their emphasis on farmer-centred management, have been presented as panaceas for overcoming weaknesses in irrigation systems. Participatory Irrigation Management (PIM) has assumed such a high status that it is regularly mandated by donors sponsoring irrigation upgrades in [...] Read more.

For many decades, participatory approaches, with their emphasis on farmer-centred management, have been presented as panaceas for overcoming weaknesses in irrigation systems. Participatory Irrigation Management (PIM) has assumed such a high status that it is regularly mandated by donors sponsoring irrigation upgrades in poor countries. However, the success of PIM is mixed, and economic analysis can help explain why PIM might work in some settings and not in others. This Special Issue focusses on PIM and aims to scrutinise its usefulness, particularly in South Asia. The focus on South Asian irrigation is driven by the reality that smallholder agriculture is destined to be the mainstay for this most populous region, at least in the medium term, and finding solutions to raise agricultural productivity is a high priority. The Special Issue comprises nine papers employing several strands of economics, including New Institutional Economics, Game Theory, and Behavioural Economics. A synopsis of each paper is provided in this editorial. Full article

(This article belongs to the Special Issue Using Applied Economics to Study Participatory Irrigation Institutions and their Impact in South Asia)

14 pages, 1464 KiB

Open AccessEditor’s ChoiceConcept Paper

Macroplastic Storage and Remobilization in Rivers

by Maciej Liro, Tim van Emmerik, Bartłomiej Wyżga, Justyna Liro and Paweł Mikuś

Water 2020, 12(7), 2055; https://doi.org/10.3390/w12072055 - 20 Jul 2020

Cited by 102 | Viewed by 10184

Abstract

The paper presents a conceptual model of the route of macroplastic debris (>5 mm) through a fluvial system, which can support future works on the overlooked processes of macroplastic storage and remobilization in rivers. We divided the macroplastic route into (1) input, (2) [...] Read more.

The paper presents a conceptual model of the route of macroplastic debris (>5 mm) through a fluvial system, which can support future works on the overlooked processes of macroplastic storage and remobilization in rivers. We divided the macroplastic route into (1) input, (2) transport, (3) storage, (4) remobilization and (5) output phases. Phase 1 is mainly controlled by humans, phases 2–4 by fluvial processes, and phase 5 by both types of controls. We hypothesize that the natural characteristics of fluvial systems and their modification by dam reservoirs and flood embankments construction are key controls on macroplastic storage and remobilization in rivers. The zone of macroplastic storage can be defined as a river floodplain inundated since the beginning of widespread disposal of plastic waste to the environment in the 1960s and the remobilization zone as a part of the storage zone influenced by floodwaters and bank erosion. The amount of macroplastic in both zones can be estimated using data on the abundance of surface- and subsurface-stored macroplastic and the lateral and vertical extent of the zones. Our model creates the framework for estimation of how much plastic has accumulated in rivers and will be present in future riverscapes. Full article

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17 pages, 3659 KiB

Open AccessArticle

Feasible Ways Promoting Nitrate Removal in Riparian Zone Downstream of a Regulated River

by Dongsheng Liu, Bei Zhu, Haoyu Zhu and Jian Zhao

Water 2020, 12(7), 2054; https://doi.org/10.3390/w12072054 - 20 Jul 2020

Viewed by 2085

Abstract

Set in the downstream riparian zone of Xin’an River Dam, this paper established a 2D transversal coupling flow and solute transport and reaction model by verification within situ groundwater level and temperature. The denitrifying methods and principles in the riparian zone from the [...] Read more.

Set in the downstream riparian zone of Xin’an River Dam, this paper established a 2D transversal coupling flow and solute transport and reaction model by verification within situ groundwater level and temperature. The denitrifying methods and principles in the riparian zone from the perspective of hyporheic exchange were explored, which provided a basis for the engineering techniques for river ecological restoration. Our studies have shown that under the condition of water level fluctuation, a biological method such as adding denitrifying bacteria biomass to a fixed degree (the same below) can greatly increase the denitrifying rate (1.52 g/d) in the riparian zone; chemical methods such as adding organic carbon into the surface water or groundwater can increase the total riparian nitrate removal (8.00–8.18 g) and its efficiency (19.5–20.0%) to a great extent; hydrogeological methods such as silt cleaning of the aquifer surface or local pumping around the contaminated area can increase the total riparian nitrate removal (1.06–14.8 g) to some extent, but correspondingly reduce the denitrifying efficiency (0.95–1.4%); physical methods such as designing the bank form into gentle slope or concave shape can slightly increase the total riparian nitrate removal (0.22–0.52 g) and correspondingly improve the denitrifying efficiency (0.25–0.85%). At the application level of river ecological restoration, integrated adopting the above methods can make the riparian denitrifying effect “fast and good”. Full article

(This article belongs to the Special Issue Hydrochemical Characteristics of Groundwater)

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14 pages, 2197 KiB

Open AccessArticle

Sorption Characteristics and Removal Efficiency of Organic Micropollutants in Drinking Water Using Granular Activated Carbon (GAC) in Pilot-Scale and Full-Scale Tests

by Oksana Golovko, Luana de Brito Anton, Claudia Cascone, Lutz Ahrens, Elin Lavonen and Stephan J. Köhler

Water 2020, 12(7), 2053; https://doi.org/10.3390/w12072053 - 19 Jul 2020

Cited by 25 | Viewed by 7204

Abstract

Granulated active carbon (GAC) is commonly used as a chemical barrier for the removal of organic micropollutants (OMPs) in drinking water treatment plants (DWTPs). However, little is known about the impact of dissolved organic carbon (DOC) and its long-term performance with regard to [...] Read more.

Granulated active carbon (GAC) is commonly used as a chemical barrier for the removal of organic micropollutants (OMPs) in drinking water treatment plants (DWTPs). However, little is known about the impact of dissolved organic carbon (DOC) and its long-term performance with regard to OMP removal efficiency. This study examined the performance of two GAC types (Norit 830W and Filtrasorb 400) in the removal of OMPs and DOC from natural lake water, in pilot-scale and full-scale tests run for almost one year. Potential early warning indicators of the exhaustion of GAC sorption capacity were also evaluated. The seven OMPs investigated (carbamazepine, lamotrigine, cetirizine, fexofenadine, oxazepam, fluconazole and N,N-diethyl-meta-toluamide (DEET)) all showed decreasing removal efficiencies after ~20,000 bed volumes (BV) in the pilot-scale Norit 830W and Filtrasorb 400 columns. However, columns with an 18-min empty bed contact time (EBCT) showed better performances than columns with 6-min EBCT. DEET was the OMP adsorbed most weakly. We found that DOC concentrations, methylene blue sorption kinetics, UV and fluorescence did not sufficiently explain the OMP breakthrough in the GAC columns. We concluded that carbamazepine, lamotrigine and fexofenadine can be used as indicators of decreasing GAC adsorption performance, due to their later breakthrough. Based on the results, UV and fluorescence removal could be used for the early detection of declining DOC removal, and online solid-phase extraction (SPE)–liquid chromatography–tandem mass spectrometry (SPE-LC-MS/MS) could be used for the early detection of OMPs in drinking water. Full article

(This article belongs to the Special Issue Drinking Water Treatment Optimization: Challenges and Innovations)

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14 pages, 1866 KiB

Open AccessEditor’s ChoiceArticle

Kinetic and Prediction Modeling Studies of Organic Pollutants Removal from Municipal Wastewater using Moringa oleifera Biomass as a Coagulant

by Bashir Adelodun, Matthew Segun Ogunshina, Fidelis Odedishemi Ajibade, Taofeeq Sholagberu Abdulkadir, Hashim Olalekan Bakare and Kyung Sook Choi

Water 2020, 12(7), 2052; https://doi.org/10.3390/w12072052 - 19 Jul 2020

Cited by 26 | Viewed by 4932

Abstract

This study investigated the potential of Moringa oleifera (MO) seed biomass as a coagulant for the removal of turbidity, biochemical oxygen demand (BOD), and chemical oxygen demand (COD) of municipal wastewater. Triplicated laboratory experiments using MO coagulant added at varying treatment dosages of [...] Read more.

This study investigated the potential of Moringa oleifera (MO) seed biomass as a coagulant for the removal of turbidity, biochemical oxygen demand (BOD), and chemical oxygen demand (COD) of municipal wastewater. Triplicated laboratory experiments using MO coagulant added at varying treatment dosages of 50, 100, 150, 200 mg/L, and a control (0 mg/L) treatment were performed for a settling period of 250 min at room temperature. Kinetics and prediction variables of cumulative turbidity, BOD, and COD removal were estimated using simplified first order and modified Gompertz models. Results showed that the maximum removal of turbidity, BOD, and COD were 94.44%, 68.72%, and 57.61%, respectively, using an MO dose of 150 mg/L. Various kinetic parameters, such as rate constant (r), measured (RE_m) versus predicted (RE_p) cumulative removal, and specific pollutant removal rate (µ_m), were also maximum when an MO dose of 150 mg/L was added, the standard error being below 5%. The developed models were successfully validated over multiple observations. This study suggests low cost and sustainable removal of turbidity, BOD, and COD of municipal wastewater using MO seed biomass as a coagulant. Full article

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

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42 pages, 7352 KiB

Open AccessEditor’s ChoiceReview

State of the Art and Recent Advancements in the Modelling of Land Subsidence Induced by Groundwater Withdrawal

by Artur Guzy and Agnieszka A. Malinowska

Water 2020, 12(7), 2051; https://doi.org/10.3390/w12072051 - 19 Jul 2020

Cited by 75 | Viewed by 12148

Abstract

Land subsidence is probably one of the most evident environmental effects of groundwater pumping. Globally, freshwater demand is the leading cause of this phenomenon. Land subsidence induced by aquifer system drainage can reach total values of up to 14.5 m. The spatial extension [...] Read more.

Land subsidence is probably one of the most evident environmental effects of groundwater pumping. Globally, freshwater demand is the leading cause of this phenomenon. Land subsidence induced by aquifer system drainage can reach total values of up to 14.5 m. The spatial extension of this phenomenon is usually extensive and is often difficult to define clearly. Aquifer compaction contributes to many socio-economic effects and high infrastructure-related damage costs. Currently, many methods are used to analyze aquifer compaction. These include the fundamental relationship between groundwater head and groundwater flow direction, water pressure and aquifer matrix compressibility. Such solutions enable satisfactory modelling results. However, further research is needed to allow more efficient modelling of aquifer compaction. Recently, satellite radar interferometry (InSAR) has contributed to significant progress in monitoring and determining the spatio-temporal land subsidence distributions worldwide. Therefore, implementation of this approach can pave the way to the development of more efficient aquifer compaction models. This paper presents (1) a comprehensive review of models used to predict land surface displacements caused by aquifer drainage, as well as (2) recent advances, and (3) a summary of InSAR implementation in recent years to support the aquifer compaction modelling process. Full article

(This article belongs to the Special Issue Groundwater Resilience to Climate Change and High Pressure)

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24 pages, 5501 KiB

Open AccessEditor’s ChoiceReview

Flood Risk Analysis and Assessment, Applications and Uncertainties: A Bibliometric Review

by Andrés Díez-Herrero and Julio Garrote

Water 2020, 12(7), 2050; https://doi.org/10.3390/w12072050 - 18 Jul 2020

Cited by 58 | Viewed by 9608

Abstract

Studies looking at flood risk analysis and assessment (FRA) reviews are not customary, and they usually approach to methodological and spatial scale issues, uncertainty, mapping or economic damage topics. However, most of these reviews provide a snapshot of the scientific state of the [...] Read more.

Studies looking at flood risk analysis and assessment (FRA) reviews are not customary, and they usually approach to methodological and spatial scale issues, uncertainty, mapping or economic damage topics. However, most of these reviews provide a snapshot of the scientific state of the art of FRA that shows only a partial view, focused on a limited number of selected methods and approaches. In this paper, we apply a bibliometric analysis using the Web of Science (WoS) database to assess the historic evolution and future prospects (emerging fields of application) of FRA. The scientific production of FRA has increased considerably in the past decade. At the beginning, US researchers dominated the field, but now they have been overtaken by the Chinese. The Netherlands and Germany may be highlighted for their more complete analyses and assessments (e.g., including an uncertainty analysis of FRA results), and this can be related to the presence of competitive research groups focused on FRA. Regarding FRA fields of application, resilience analysis shows some growth in recent years while land planning, risk perception and risk warning show a slight decrease in the number of papers published. Global warming appears to dominate part of future FRA production, which affects both fluvial and coastal floods. This, together with the improvement of economic evaluation and psycho-social analysis, appear to be the main trends for the future evolution of FRA. Finally, we cannot ignore the increase in analysis using big data analysis, machine learning techniques, and remote sensing data (particularly in the case of UAV sensors data). Full article

(This article belongs to the Special Issue Flood Risk Assessments: Applications and Uncertainties)

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26 pages, 10662 KiB

Open AccessArticle

Non-Fickian Solute Transport in Rough-Walled Fractures: The Effect of Contact Area

by Yingtao Hu, Wenjie Xu, Liangtong Zhan, Zuyang Ye and Yunmin Chen

Water 2020, 12(7), 2049; https://doi.org/10.3390/w12072049 - 18 Jul 2020

Cited by 16 | Viewed by 3102

Abstract

The influence of contact area, caused by normal deformation, on fluid flow and solute transport through three-dimensional (3D) rock fractures is investigated. Fracture surfaces with different Hurst exponents (H) were generated numerically using the modified successive random addition (SRA) method. By [...] Read more.

The influence of contact area, caused by normal deformation, on fluid flow and solute transport through three-dimensional (3D) rock fractures is investigated. Fracture surfaces with different Hurst exponents (H) were generated numerically using the modified successive random addition (SRA) method. By applying deformations normal to the fracture surface (Δu), a series of fracture models with different aperture distributions and contact area ratios (c) were simulated. The results show that the contact area between the two fracture surfaces increases and more void spaces are reduced as deformation (Δu) increases. The streamlines in the rough-walled fractures show that the contact areas result in preferential flow paths and fingering type transport. The non-Fickian characteristics of the “early arrival” and “long tail” in all of the breakthrough curves (BTCs) for fractures with different deformation (Δu) and Hurst parameters (H) were determined. The solute concentration distribution index (CDI), which quantifies the uniformity of the concentration distribution within the fracture, decreases exponential as deformation (Δu) and/or contact area ratios (c) increase, indicating that increased contact area can result in a larger delay rate of mass exchange between the immobile zone around the contact areas and the main flow channel, thus, resulting in a longer time for the solute to fill the entire fracture. The BTCs were analyzed using the continuous time random walk (CTRW) inverse model. The inverse modeling results show that the dispersion exponent

β

decreases from 1.92 to 0.81 as c increases and H decreases, suggesting that the increase in contact area and fracture surfaces enhance the magnitude of the non-Fickian transport. Full article

(This article belongs to the Section Hydrology)

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22 pages, 2723 KiB

Open AccessEditor’s ChoiceArticle

Students’ Scientific Evaluations of Water Resources

by Josh Medrano, Joshua Jaffe, Doug Lombardi, Margaret A. Holzer and Christopher Roemmele

Water 2020, 12(7), 2048; https://doi.org/10.3390/w12072048 - 18 Jul 2020

Cited by 11 | Viewed by 4806

Abstract

Socially-relevant and controversial topics, such as water issues, are subject to differences in the explanations that scientists and the public (herein, students) find plausible. Students need to be more evaluative of the validity of explanations (e.g., explanatory models) based on evidence when addressing [...] Read more.

Socially-relevant and controversial topics, such as water issues, are subject to differences in the explanations that scientists and the public (herein, students) find plausible. Students need to be more evaluative of the validity of explanations (e.g., explanatory models) based on evidence when addressing such topics. We compared two activities where students weighed connections between lines of evidence and explanations. In one activity, students were given four evidence statements and two models (one scientific and one non-scientific alternative); in the other, students chose four out of eight evidence statements and three models (two scientific and one non-scientific). Repeated measures analysis of variance (ANOVA) showed that both activities engaged students’ evaluations and differentially shifted students’ plausibility judgments and knowledge. A structural equation model suggested that students’ evaluation may influence post-instructional plausibility and knowledge; when students chose their lines of evidence and explanatory models, their evaluations were deeper, with stronger shifts toward a scientific stance and greater levels of post-instructional knowledge. The activities may help to develop students’ critical evaluation skills, a scientific practice that is key to understanding both scientific content and science as a process. Although effect sizes were modest, the results provided critical information for the final development and testing stage of these water resource instructional activities. Full article

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

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16 pages, 11985 KiB

Open AccessArticle

Evaluation of CYGNSS Observations for Flood Detection and Mapping during Sistan and Baluchestan Torrential Rain in 2020

by Mahmoud Rajabi, Hossein Nahavandchi and Mostafa Hoseini

Water 2020, 12(7), 2047; https://doi.org/10.3390/w12072047 - 18 Jul 2020

Cited by 21 | Viewed by 4142

Abstract

Flood detection and produced maps play essential roles in policymaking, planning, and implementing flood management options. Remote sensing is commonly accepted as a maximum cost-effective technology to obtain detailed information over large areas of lands and oceans. We used remote sensing observations from [...] Read more.

Flood detection and produced maps play essential roles in policymaking, planning, and implementing flood management options. Remote sensing is commonly accepted as a maximum cost-effective technology to obtain detailed information over large areas of lands and oceans. We used remote sensing observations from Global Navigation Satellite System-Reflectometry (GNSS-R) to study the potential of this technique for the retrieval of flood maps over the regions affected by the recent flood in the southeastern part of Iran. The evaluation was made using spaceborne GNSS-R measurements over the Sistan and Baluchestan provinces during torrential rain in January 2020. This area has been at a high risk of flood in recent years and needs to be continuously monitored by means of timely observations. The main dataset was acquired from the level-1 data product of the Cyclone Global Navigation Satellite System (CYGNSS) spaceborne mission. The mission consisted of a constellation of eight microsatellites with GNSS-R sensors onboard to receive forward-scattered GNSS signals from the ocean and land. We first focused on data preparation and eliminating the outliers. Afterward, the reflectivity of the surface was calculated using the bistatic radar equations formula. The flooded areas were then detected based on the analysis of the derived reflectivity. Images from Moderate-Resolution Imaging Spectroradiometer (MODIS) were used for evaluation of the results. The analysis estimated the inundated area of approximately 19,644 km² (including Jaz-Murian depression) to be affected by the flood in the south and middle parts of the Sistan and Baluchestan province. Although the main mission of CYGNSS was to measure the ocean wind speed in hurricanes and tropical cyclones, we showed the capability of detecting floods in the study area. The sensitivity of the spaceborne GNSS-R observations, together with the relatively short revisit time, highlight the potential of this technique to be used in flood detection. Future GNSS-R missions capable of collecting the reflected signals from all available multi-GNSS constellations would offer even more detailed information from the flood-affected areas. Full article

(This article belongs to the Special Issue Improving Flood Detection and Monitoring through Remote Sensing)

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14 pages, 1454 KiB

Open AccessArticle

Evaluation of Effects of Municipal Sludge Leachates on Water Quality

by Ioannis Giannakis, Christina Emmanouil and Athanasios Kungolos

Water 2020, 12(7), 2046; https://doi.org/10.3390/w12072046 - 18 Jul 2020

Cited by 7 | Viewed by 2911

Abstract

Biosolids made from municipal sludge are an attractive solution instead of chemical fertilization. Nevertheless, their effects on the ecosystem should always be considered. In the present study, anaerobically digested sludge was subjected to two leaching methods (EN 12457-2 and NEN 7341) and the [...] Read more.

Biosolids made from municipal sludge are an attractive solution instead of chemical fertilization. Nevertheless, their effects on the ecosystem should always be considered. In the present study, anaerobically digested sludge was subjected to two leaching methods (EN 12457-2 and NEN 7341) and the main physicochemical parameters were measured in the leachates. The aquatic organisms Daphnia magna and Vibrio fischeri were exposed to the leachates in order to test for adverse effects. Mixtures of biosolid/solid, simulating the high dose of 80 tn/ha, were also created, and the same parameters were measured for EN 12457-2 leachates. The results show a strong seasonal variation for the results for the municipal sludge, even though the sludge did not originate from a touristic area. The biosolid/solid mixtures did not produce toxic responses to the organism tested. Nevertheless, the parameters nitrites and nitrates in the leachates were increased in relation to control and they continued to increase even at Day 40 post-application. This increase was soil-type-dependent. The biosolids in question could be used for field fertilization, however measures should be taken against underground water nitrate pollution. Full article

(This article belongs to the Special Issue Water Quality Indices: Current and Future Trends in Evaluating Contamination of Groundwater Resources)

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13 pages, 2333 KiB

Open AccessEditor’s ChoiceArticle

The Use of Permeable Interlocking Concrete Pavement to Filter Stormwater for Non-Potable Uses in Buildings

by Enedir Ghisi, Thiago Belotto and Liseane Padilha Thives

Water 2020, 12(7), 2045; https://doi.org/10.3390/w12072045 - 18 Jul 2020

Cited by 18 | Viewed by 7496

Abstract

A reduction in potable water demand in buildings could be made by using non-potable water for certain uses, such as flushing toilets. This represents a sustainable strategy that results in potable water savings while also using an underutilised resource. This work assesses the [...] Read more.

A reduction in potable water demand in buildings could be made by using non-potable water for certain uses, such as flushing toilets. This represents a sustainable strategy that results in potable water savings while also using an underutilised resource. This work assesses the use of permeable interlocking concrete pavement to filter stormwater that could be used for non-potable purposes in buildings. Two pavement model systems were tested. One of the model systems presents a filter course layer with coarse sand and the other model system has no filter course layer. In order to evaluate the filtering capacity, the model systems were exposed to rain events. The amount of water infiltrated through the layers was measured to represent the potential quantity available for use. Stormwater runoff samples were collected from a parking lot paved with impermeable interlocked blocks and then, these were tested in both model systems. Water samples were subjected to quality tests according to the parameters recommended by the Brazilian National Water Agency. The model system with no filter course showed filtering capacity higher (88.1%) than the one with a filter course layer (78.8%). The model system with a filter course layer was able to reduce fecal coliforms (54.7%), total suspended solids (62.5%), biochemical oxygen demand (78.8%), and total phosphorus concentrations (55.6%). Biochemical oxygen demand (42.4%) and total phosphorus concentrations (44.4%) increased in the model system with no filter course layer. In conclusion, one can state that the filter course layer used in permeable interlocking concrete pavement can contribute to decreasing pollutants and can improve stormwater quality. The use of permeable interlocking concrete pavement showed to be a potential alternative for filtering stormwater prior to subsequent treatment for non-potable uses in buildings. Full article

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

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20 pages, 9791 KiB

Open AccessArticle

Evaluation of Design Storms and Critical Rainfall Durations for Flood Prediction in Partially Urbanized Catchments

by Nino Krvavica and Josip Rubinić

Water 2020, 12(7), 2044; https://doi.org/10.3390/w12072044 - 18 Jul 2020

Cited by 45 | Viewed by 6179

Abstract

This study investigates and compares several design storms for flood estimation in partially urbanized catchments. Six different design storms were considered: Euler II, alternating block method, average variability method, Huff’s curves, and uniform rainfall. Additionally, two extreme historical storms were included for comparison. [...] Read more.

This study investigates and compares several design storms for flood estimation in partially urbanized catchments. Six different design storms were considered: Euler II, alternating block method, average variability method, Huff’s curves, and uniform rainfall. Additionally, two extreme historical storms were included for comparison. A small, ungauged, partially urbanized catchment in Novigrad (Croatia) was chosen as a study area to account for the infiltration impact on the rainfall-runoff process. The performance of each design storm was assessed based on the flood modeling results, namely the water depth, water velocity, flow rate, and overall flood extent. Furthermore, several rainfall durations were considered to identify a critical scenario. The excess rainfall was computed using the Soil Conservation Service’s Curve Number method, and two-dimensional flooding simulations were performed by the HEC-RAS model. The results confirmed that the choice of the design storm and the rainfall duration has a significant impact on the flood modeling results. Overall, design storms constructed only from IDF curves overestimated flooding in comparison to historical events, whereas design storms derived from the analysis of observed temporal patterns matched or slightly underestimated the flooding results. Of the six considered design storms, the average variability method showed the closest agreement with historical storms. Full article

(This article belongs to the Special Issue Urban Rainwater and Flood Management)

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