Water

22 pages, 1514 KiB

Open AccessEditor’s ChoiceArticle

Integrated Assessment—How Does It Help Unpack Water Access by Marginalized Farmers?

by Serena H. Hamilton, Wendy S. Merritt, Mahanambrota Das, M. Wakilur Rahman, Sumana S. Bhuiya, Lucy Carter, Michaela Cosijn, Christian H. Roth, Sambhu Singha and Geoffrey J. Syme

Water 2020, 12(12), 3444; https://doi.org/10.3390/w12123444 - 8 Dec 2020

Cited by 3 | Viewed by 3021

Abstract

Water is critical to the lives and livelihoods of rural communities in developing countries; however, access to water can be inequitable within communities. This paper uses a generalized integrated assessment approach to explore the determinants of water access by marginalized farmers in two [...] Read more.

Water is critical to the lives and livelihoods of rural communities in developing countries; however, access to water can be inequitable within communities. This paper uses a generalized integrated assessment approach to explore the determinants of water access by marginalized farmers in two villages in coastal Bangladesh, before and after the setup of local water institutions. The study was part of a broader project aimed at promoting socially inclusive agricultural intensification. An integrative framework was developed in this study to capture and link the diverse range of factors that influence the distribution of water, including the often-overlooked role of social dynamics and governance arrangements. While interventions around improving water resource infrastructure can be critical for freshwater availability, the case studies show that a breakdown of asymmetric power structures may also be needed for water access to all individuals, especially marginalized groups. Establishing a community-based water institution on its own does not necessarily address power issues in a community. It is imperative that the agency and capacities of the marginalized members are developed and that the institutional arrangements foster an enabling environment for marginalized members to influence decision making. Integrated assessment allowed the case studies to be explored from multiple perspectives so as to gain a greater understanding of the barriers and levers to obtaining equitable outcomes from water interventions. Full article

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

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24 pages, 4527 KiB

Open AccessEditor’s ChoiceArticle

Integrating In Situ and Ocean Color Data to Evaluate Ecological Quality under the Water Framework Directive

by Ana C. Brito, Paloma Garrido-Amador, Carla Gameiro, Marta Nogueira, Maria Teresa Moita and Maria Teresa Cabrita

Water 2020, 12(12), 3443; https://doi.org/10.3390/w12123443 - 8 Dec 2020

Cited by 10 | Viewed by 3280

Abstract

The Water Framework Directive (WFD) aims at evaluating the ecological status of European coastal water bodies (CWBs). This is a rather complex task and first requires the use of long-term databases to assess the effect of anthropogenic pressure on biological communities. An in [...] Read more.

The Water Framework Directive (WFD) aims at evaluating the ecological status of European coastal water bodies (CWBs). This is a rather complex task and first requires the use of long-term databases to assess the effect of anthropogenic pressure on biological communities. An in situ dataset was assembled using concomitant biological, i.e., chlorophyll a (Chl a) and environmental data, covering the years from 1995 to 2014, to enable a comprehensive assessment of eutrophication in the Western Iberia Coast (WIC). Given the temporal gaps in the dataset, especially in terms of Chl a, satellite observations were used to complement it. Positive relationships between Chl a 90th percentile and nitrogen concentrations were obtained. The Land-Uses Simplified Index (LUSI), as a pressure indicator, showed no relationship with Chl a, except in Galicia, but it highlighted a higher continental pressure in the Portuguese CWBs in comparison with Galician waters. In general terms, the trophic index (TRIX) showed that none of the CWBs were in degraded conditions. Nevertheless, the relatively high TRIX and LUSI values obtained for the water body in front of Tagus estuary suggest that this area should be subject to continued monitoring. Results highlighted the usefulness of satellite data in water quality assessments and set the background levels for the implementation of operational monitoring based on satellite Chl a. In the future, low uncertainty and harmonized satellite products across countries should be provided. Moreover, the assessment of satellite-based eutrophication indicators should also include metrics on phytoplankton phenology and community structure. Full article

(This article belongs to the Special Issue The WFD 20 Years After—Ecological Status Assessment and Restoration of Aquatic Ecosystems)

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19 pages, 1167 KiB

Open AccessEditor’s ChoiceArticle

Evaluation of Environmental Quality of Mediterranean Coastal Lagoons Using Persistent Organic Pollutants and Metals in Thick-Lipped Grey Mullet

by Chiara Leone, Fabrizio Capoccioni, Claude Belpaire, Govindan Malarvannan, Giulia Poma, Adrian Covaci, Lorenzo Tancioni, Michela Contò and Eleonora Ciccotti

Water 2020, 12(12), 3450; https://doi.org/10.3390/w12123450 - 8 Dec 2020

Cited by 7 | Viewed by 3682

Abstract

The evaluation of past and present anthropogenic impacts affecting the ecological quality status of transitional ecosystems is crucial from the perspective of protecting them from further deterioration, and to evaluate remediation and restoration measures. Contamination patterns of thick-lipped grey mullet from two Mediterranean [...] Read more.

The evaluation of past and present anthropogenic impacts affecting the ecological quality status of transitional ecosystems is crucial from the perspective of protecting them from further deterioration, and to evaluate remediation and restoration measures. Contamination patterns of thick-lipped grey mullet from two Mediterranean coastal lagoons within a protected area in Italy were assessed and compared in order to evaluate their overall quality status and to collect information that can provide useful feedback on management choices aimed at enhancing environmental quality and biodiversity conservation. The quality status of the two lagoons was evaluated by an environmental assessment methodology based on indicators of direct and indirect human pressures, while a broad range of analyses were carried out to determine the presence and concentration of persistent organic pollutants (POPs) and metals in fish muscle tissue. A good quality status resulted for both lagoons, and an overall limited anthropogenic impact in the surrounding area. This could account for POPs and metal contamination levels found in mullet, although limited, and relating to their patterns. The overlap of results achieved with the two evaluation approaches can provide support for management choices in Mediterranean lagoon environments, especially for those committed to the protection and conservation of biodiversity. Full article

(This article belongs to the Special Issue Aquatic Ecosafety: Threats, Disturbances, Environmental Monitors and Bioremediation Actions)

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13 pages, 2453 KiB

Open AccessEditor’s ChoiceArticle

Comparison of Zooplankton Community Patterns in Relation to Sediment Disturbances by Dredging in the Guemho River, Korea

by Eui-Jeong Ko, Dong-Kyun Kim, Eun-Song Jung, Yu-Ji Heo, Gea-Jae Joo and Hyun-Woo Kim

Water 2020, 12(12), 3434; https://doi.org/10.3390/w12123434 - 7 Dec 2020

Cited by 7 | Viewed by 3259

Abstract

This study aimed to determine whether a swimming-type (planktonic and epiphytic) zooplankton group compared with the taxonomic group is appropriate to indicate the environmental changes caused by dredging. Water sampling in the littoral zone was conducted from 2007 to 2015, including the dredging [...] Read more.

This study aimed to determine whether a swimming-type (planktonic and epiphytic) zooplankton group compared with the taxonomic group is appropriate to indicate the environmental changes caused by dredging. Water sampling in the littoral zone was conducted from 2007 to 2015, including the dredging period from October 2010 to June 2012. The water quality, number of species, population densities, and biotic indices were compared for both dredging period and grouping type. Nine of 11 water quality parameters were changed by the dredging period. The results showed that the rotifer and planktonic groups were consistently dominant. In all groups, population density was the lowest during the dredging period. After dredging, both the number of species and population density increased only in the epiphytic group. The dominant species, including Polyarthra vulgaris, Brachionus calyciflorus, B. rubens, and Bosmina longirostris, were included in the planktonic group for 9 years. Evenness did not differ, but diversity increased after the dredging period. This study showed that zooplankton could be used as a supplemental biological assessment tool for evaluating the impact of river dredging. Full article

(This article belongs to the Section Biodiversity and Functionality of Aquatic Ecosystems)

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17 pages, 2819 KiB

Open AccessEditor’s ChoiceArticle

Developing Pseudo Continuous Pedotransfer Functions for International Soils Measured with the Evaporation Method and the HYPROP System: I. The Soil Water Retention Curve

by Amninder Singh, Amir Haghverdi, Hasan Sabri Öztürk and Wolfgang Durner

Water 2020, 12(12), 3425; https://doi.org/10.3390/w12123425 - 6 Dec 2020

Cited by 12 | Viewed by 4114

Abstract

Direct measurements of soil hydraulic properties are time-consuming, challenging, and often expensive. Therefore, their indirect estimation via pedotransfer functions (PTFs) based on easily collected properties like soil texture, bulk density, and organic matter content is desirable. This study was carried out to assess [...] Read more.

Direct measurements of soil hydraulic properties are time-consuming, challenging, and often expensive. Therefore, their indirect estimation via pedotransfer functions (PTFs) based on easily collected properties like soil texture, bulk density, and organic matter content is desirable. This study was carried out to assess the accuracy of the pseudo continuous neural network PTF (PC_NN-PTF) approach for estimating the soil water retention curve of 153 international soils (a total of 12,654 measured water retention pairs) measured via the evaporation method. In addition, an independent data set from Turkey (79 soil samples with 7729 measured data pairs) was used to evaluate the reliability of the PC_NN-PTF. The best PC_NN-PTF showed high accuracy (root mean square error (RMSE) = 0.043 cm³ cm⁻³) and reliability (RMSE = 0.061 cm³ cm⁻³). When Turkish soil samples were incorporated into the training data set, the performance of the PC_NN-PTF was enhanced by 33%. Therefore, to further improve the performance of the PC_NN-PTF for new regions, we recommend the incorporation of local soils, when available, into the international data sets and developing new sets of PC_NN-PTFs. Full article

(This article belongs to the Special Issue Soft Computing for Water and Aquatic Resource Management)

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13 pages, 3233 KiB

Open AccessEditor’s ChoiceArticle

Sediment Carbon Variations in the Venice Lagoon and Other Transitional Water Systems of the Northern Adriatic Sea

by Adriano Sfriso, Alessandro Buosi, Yari Tomio, Abdul-Salam Juhmani, Stefania Chiesa, Marta Greco, Chiara Gazzola, Michele Mistri, Cristina Munari and Andrea Augusto Sfriso

Water 2020, 12(12), 3430; https://doi.org/10.3390/w12123430 - 6 Dec 2020

Cited by 5 | Viewed by 3811

Abstract

The concentrations of inorganic, organic and total carbon, and some sedimentary parameters (sediment density, fines, pH, and shell fragments), have been analyzed in surface sediments of the Venice Lagoon since 1987. Environmental scenarios, characterized by different anthropogenic impacts, have been considered, especially in [...] Read more.

The concentrations of inorganic, organic and total carbon, and some sedimentary parameters (sediment density, fines, pH, and shell fragments), have been analyzed in surface sediments of the Venice Lagoon since 1987. Environmental scenarios, characterized by different anthropogenic impacts, have been considered, especially in the central basin where more information is available. Data collected in 2009 in the lagoons and ponds of Po Delta, in Comacchio Valleys and Pialassa della Baiona have been also considered and analyzed together with those recorded in the whole Venice Lagoon in 2011. The results show a strong correlation of the inorganic carbon (Cinorg) with the carbonatic or siliceous origins of the sediments and changes of both Cinorg and organic carbon (Corg) according to different anthropogenic impacts, especially eutrophication and clam-fishing activities. Higher sediment density, grain-size, and pH were associated to good-high ecological conditions and the higher presence of inorganic carbon of biological origin (shell fragments and calcified macroalgal fragments). Conversely, Corg, which is associated to eutrophic conditions, was strongly affected by the sediment disturbance and the presence of high concentrations of bivalves which enhance its consumption. Full article

(This article belongs to the Special Issue Aquatic Ecosafety: Threats, Disturbances, Environmental Monitors and Bioremediation Actions)

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15 pages, 3464 KiB

Open AccessEditor’s ChoiceArticle

Small Floodplain Reservoirs in the Face of Climate Change—Sink or Source of Nutrients?

by Joanna Gmitrowicz-Iwan, Sławomir Ligęza, Jacek Pranagal, Halina Smal and Heronim Olenderek

Water 2020, 12(12), 3423; https://doi.org/10.3390/w12123423 - 5 Dec 2020

Cited by 8 | Viewed by 2367

Abstract

Despite various water protection measures, good water quality and reduction of nutrient loads seem very distant goals, largely due to limited knowledge of processes occurring in river valleys. Our study aimed at establishing the role of small floodplain reservoirs in the eutrophication processes, [...] Read more.

Despite various water protection measures, good water quality and reduction of nutrient loads seem very distant goals, largely due to limited knowledge of processes occurring in river valleys. Our study aimed at establishing the role of small floodplain reservoirs in the eutrophication processes, in the face of recent climate changes. The content of phosphorus and nitrogen compounds was determined in sediments and water of small floodplain reservoirs, (the Vistula River Valley, Poland) using spectrophotometric and Kjeldahl’s method. Nutrient loads in sediments were linked to the texture and total organic carbon content. Seasonal changes in water quality were strictly connected to changing weather conditions, flood and drought. The concentrations of PO₄³⁻ and NO₃⁻ were found to rise after summer flooding. Increases in NH₄⁺, total phosphorus (TP) and total nitrogen (TN) were correlated with the surface water area reduction in the reservoirs, which during the year of the study was on average 62%. Therefore, small floodplain reservoirs could be considered simultaneously as sinks and sources of nutrients. On the one hand, they accumulate P and N compounds carried by the river during the flood. On the other hand, climate change cause that small floodplain reservoirs may be responsible for enhanced biomass production. Full article

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

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19 pages, 2620 KiB

Open AccessEditor’s ChoiceArticle

Impact of Nutrients, Temperatures, and a Heat Wave on Zooplankton Community Structure: An Experimental Approach

by Uğur Işkın, Nur Filiz, Yu Cao, Érika M. Neif, Burak Öğlü, Torben L. Lauridsen, Thomas A. Davidson, Martin Søndergaard, Ülkü Nihan Tavşanoğlu, Meryem Beklioğlu and Erik Jeppesen

Water 2020, 12(12), 3416; https://doi.org/10.3390/w12123416 - 4 Dec 2020

Cited by 24 | Viewed by 6234

Abstract

Shallow lakes are globally the most numerous water bodies and are sensitive to external perturbations, including eutrophication and climate change, which threaten their functioning. Extreme events, such as heat waves (HWs), are expected to become more frequent with global warming. To elucidate the [...] Read more.

Shallow lakes are globally the most numerous water bodies and are sensitive to external perturbations, including eutrophication and climate change, which threaten their functioning. Extreme events, such as heat waves (HWs), are expected to become more frequent with global warming. To elucidate the effects of nutrients, warming, and HWs on zooplankton community structure, we conducted an experiment in 24 flow-through mesocosms (1.9 m in diameter, 1.0 m deep) imitating shallow lakes. The mesocosms have two nutrient levels (high (HN) and low (LN)) crossed with three temperature scenarios based on the Intergovernmental Panel on Climate Change (IPCC) projections of likely warming scenarios (unheated, A2, and A2 + 50%). The mesocosms had been running continuously with these treatments for 11 years prior to the HW simulation, which consisted of an additional 5 °C increase in temperature applied from 1 July to 1 August 2014. The results showed that nutrient effects on the zooplankton community composition and abundance were greater than temperature effects for the period before, during, and after the HW. Before the HW, taxon richness was higher, and functional group diversity and evenness were lower in HN than in LN. We also found a lower biomass of large Cladocera and a lower zooplankton: phytoplankton ratio, indicating higher fish predation in HN than in LN. Concerning the temperature treatment, we found some indication of higher fish predation with warming in LN, but no clear effects in HN. There was a positive nutrient and warming interaction for the biomass of total zooplankton, large and small Copepoda, and the zooplankton: phytoplankton ratio during the HW, which was attributed to recorded HW-induced fish kill. The pattern after the HW largely followed the HW response. Our results suggest a strong nutrient effect on zooplankton, while the effect of temperature treatment and the 5 °C HW was comparatively modest, and the changes likely largely reflected changes in predation. Full article

(This article belongs to the Special Issue Effect of Extreme Climate Events on Lake Ecosystems)

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13 pages, 2450 KiB

Open AccessEditor’s ChoiceArticle

Prediction of Water Level and Water Quality Using a CNN-LSTM Combined Deep Learning Approach

by Sang-Soo Baek, Jongcheol Pyo and Jong Ahn Chun

Water 2020, 12(12), 3399; https://doi.org/10.3390/w12123399 - 3 Dec 2020

Cited by 210 | Viewed by 14568

Abstract

A Convolutional Neural Network (CNN)-Long Short-Term Memory (LSTM) combined with a deep learning approach was created by combining CNN and LSTM networks simulated water quality including total nitrogen, total phosphorous, and total organic carbon. Water level and water quality data in the Nakdong [...] Read more.

A Convolutional Neural Network (CNN)-Long Short-Term Memory (LSTM) combined with a deep learning approach was created by combining CNN and LSTM networks simulated water quality including total nitrogen, total phosphorous, and total organic carbon. Water level and water quality data in the Nakdong river basin were collected from the Water Resources Management Information System (WAMIS) and the Real-Time Water Quality Information, respectively. The rainfall radar image and operation information of estuary barrage were also collected from the Korea Meteorological Administration. In this study, CNN was used to simulate the water level and LSTM used for water quality. The entire simulation period was 1 January 2016–16 November 2017 and divided into two parts: (1) calibration (1 January 2016–1 March 2017); and (2) validation (2 March 2017–16 November 2017). This study revealed that the performances of both of the CNN and LSTM models were in the “very good” range with above the Nash–Sutcliffe efficiency value of 0.75 and that those models well represented the temporal variations of the pollutants in Nakdong river basin (NRB). It is concluded that the proposed approach in this study can be useful to accurately simulate the water level and water quality. Full article

(This article belongs to the Special Issue Water-Quality Modeling)

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17 pages, 5676 KiB

Open AccessEditor’s ChoiceArticle

Warming of Near-Surface Summer Water Temperatures in Lakes of the Conterminous United States

by Roger W. Bachmann, Daniel E. Canfield, Jr., Sapna Sharma and Vincent Lecours

Water 2020, 12(12), 3381; https://doi.org/10.3390/w12123381 - 2 Dec 2020

Cited by 9 | Viewed by 3042

Abstract

Because warming water temperatures have widespread consequences for freshwater communities, we were interested in estimating the patterns and rates of change of near-surface summer water temperatures in United States lakes. We developed multiple regression models to relate daily surface water temperatures in lakes [...] Read more.

Because warming water temperatures have widespread consequences for freshwater communities, we were interested in estimating the patterns and rates of change of near-surface summer water temperatures in United States lakes. We developed multiple regression models to relate daily surface water temperatures in lakes of the conterminous United States to 8-day average air temperatures, latitude, elevation, and sampling month and year using data from 5723 lake samples in the months of June-September during the period 1981–2018. Our model explained 79% of the variation with a root-mean-square error of 1.69 °C. We predicted monthly average near-surface water temperatures for 1033 lakes for each year from 1981 through 2018. Lakes across the conterminous United States have been warming for the period 1981–2018 at an average heating rate of 0.32 °C per decade for the summer months (June–September). The average summer warming from 1981–2018 would be the equivalent of a lake decreasing 259 m in elevation or moving 233 km south. On the basis of national air temperatures starting in 1895, it was inferred that lake water temperatures are variable from year to year and have been steadily increasing since 1964, but that maximum temperatures in the 1930s were just as warm as those in 2008–2018. Full article

(This article belongs to the Section Biodiversity and Functionality of Aquatic Ecosystems)

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17 pages, 2722 KiB

Open AccessEditor’s ChoiceReview

Literature Review: Global Neonicotinoid Insecticide Occurrence in Aquatic Environments

by Josephus F. Borsuah, Tiffany L. Messer, Daniel D. Snow, Steve D. Comfort and Aaron R. Mittelstet

Water 2020, 12(12), 3388; https://doi.org/10.3390/w12123388 - 2 Dec 2020

Cited by 119 | Viewed by 11339

Abstract

Neonicotinoids have been the most commonly used insecticides since the early 1990s. Despite their efficacy in improving crop protection and management, these agrochemicals have gained recent attention for their negative impacts on non-target species such as honeybees and aquatic invertebrates. In recent years, [...] Read more.

Neonicotinoids have been the most commonly used insecticides since the early 1990s. Despite their efficacy in improving crop protection and management, these agrochemicals have gained recent attention for their negative impacts on non-target species such as honeybees and aquatic invertebrates. In recent years, neonicotinoids have been detected in rivers and streams across the world. Determining and predicting the exposure potential of neonicotinoids in surface water requires a thorough understanding of their fate and transport mechanisms. Therefore, our objective was to provide a comprehensive review of neonicotinoids with a focus on their fate and transport mechanisms to and within surface waters and their occurrence in waterways throughout the world. A better understanding of fate and transport mechanisms will enable researchers to accurately predict occurrence and persistence of insecticides entering surface waters and potential exposure to non-target organisms in agricultural intensive regions. This review has direct implications on how neonicotinoids are monitored and degraded in aquatic ecosystems. Further, an improved understanding of the fate and transport of neonicotinoids aide natural resource practitioners in the development and implementation of effective best management practices to reduce the potential impact and exposure of neonicotinoids in waterways and aquatic ecosystems. Full article

(This article belongs to the Special Issue Mitigating the Impacts of Agricultural Water Pollution on River Ecology)

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12 pages, 1442 KiB

Open AccessEditor’s ChoiceArticle

Sustainable Exploitation of Dominant Fishes in the Largest Estuary in Southeastern China

by Linlong Wang, Li Lin, Yuan Li, Yankuo Xing and Bin Kang

Water 2020, 12(12), 3390; https://doi.org/10.3390/w12123390 - 2 Dec 2020

Cited by 11 | Viewed by 2800

Abstract

Globally, marine fisheries have declined under multiple stresses including overfishing, climate change, and habitat degradation. The Min River Estuary, as the largest estuary in southeastern China, has confronted this situation over recent decades. In this study, the dominant species of fish stocks in [...] Read more.

Globally, marine fisheries have declined under multiple stresses including overfishing, climate change, and habitat degradation. The Min River Estuary, as the largest estuary in southeastern China, has confronted this situation over recent decades. In this study, the dominant species of fish stocks in the Min River Estuary, including Coilia mystus, Cynoglossus abbreviates, Collichthys lucidus, Amblychaeturichthys hexanema, Polydactylus sextarius, Harpodon nehereus, and Secutor ruconius, were evaluated by the length-based Bayesian biomass estimator method (LBB). Outcomes could be grouped into three categories as healthy, showing the lowest exploitation rate (E: 0.31–0.43) and highest relative biomass (B/B_msy: 1.30–1.90), including S. ruconius, C. mystus, and H. nehereus; overfished, with a medium E (0.50–0.58) and B/B_msy (0.68–0.79), including A. hexanema and C. abbreviates; and collapsed, with the highest E (0.89–0.92) and lowest B/B_msy (0.03–0.21), including C. lucidus and P.sextarius. Corresponding imperative countermeasures such as using larger-sized mesh gears and reducing fishing intensity should be deployed according to the current status of each species for sustainable fishery exploitation and fish conservation. Full article

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

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17 pages, 1085 KiB

Open AccessEditor’s ChoiceReview

Water and Climate Governance in Deltas: On the Relevance of Anticipatory, Interactive, and Transformative Modes of Governance

by Annisa Triyanti, Dries L. T. Hegger and Peter P. J. Driessen

Water 2020, 12(12), 3391; https://doi.org/10.3390/w12123391 - 2 Dec 2020

Cited by 13 | Viewed by 3823

Abstract

Deltas worldwide have been experiencing pressures and challenges exacerbated by climate change. An explicit focus on deltas is lacking in various bodies of literature, although present in those bodies focusing on the resilience of social-ecological systems. However, overall, literature relevant for addressing water [...] Read more.

Deltas worldwide have been experiencing pressures and challenges exacerbated by climate change. An explicit focus on deltas is lacking in various bodies of literature, although present in those bodies focusing on the resilience of social-ecological systems. However, overall, literature relevant for addressing water and climate governance in deltas is arguably still fragmented, leading to knowledge gaps and unexplored opportunities with regards to the development of delta-oriented governance strategies. To address this knowledge gap, we conducted a systematic literature review focusing on six bodies of literature relevant to delta governance up to and including the year 2019. The results show that scholarly interest in developing transformative pathways has increased sharply over the last few years. We derived seven key governance problems and five governance solutions for resilient deltas. We found that the predominant focus is still on technocratic approaches, with limited recognition of the political dimension and few forward-looking studies. In conclusion, we suggest stimulating the development and application of more anticipatory, transformative, and interactive modes of governance to help steer the transformation to resilient and sustainable deltas. We end with suggestions for systematic, interdisciplinary, and forward-looking empirical-analytical research. Full article

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

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21 pages, 3342 KiB

Open AccessEditor’s ChoiceArticle

Phytoplankton Community Response to Nutrients, Temperatures, and a Heat Wave in Shallow Lakes: An Experimental Approach

by Nur Filiz, Uğur Işkın, Meryem Beklioğlu, Burak Öğlü, Yu Cao, Thomas A. Davidson, Martin Søndergaard, Torben L. Lauridsen and Erik Jeppesen

Water 2020, 12(12), 3394; https://doi.org/10.3390/w12123394 - 2 Dec 2020

Cited by 36 | Viewed by 5984

Abstract

Phytoplankton usually responds directly and fast to environmental fluctuations, making them useful indicators of lake ecosystem changes caused by various stressors. Here, we examined the phytoplankton community composition before, during, and after a simulated 1-month heat wave in a mesocosm facility in Silkeborg, [...] Read more.

Phytoplankton usually responds directly and fast to environmental fluctuations, making them useful indicators of lake ecosystem changes caused by various stressors. Here, we examined the phytoplankton community composition before, during, and after a simulated 1-month heat wave in a mesocosm facility in Silkeborg, Denmark. The experiment was conducted over three contrasting temperature scenarios (ambient (A0), Intergovernmental Panel on Climate Change A2 scenario (circa +3 °C, A2) and A2+ %50 (circa +4.5 °C, A2+)) crossed with two nutrient levels (low (LN) and high (HN)) with four replicates. The facility includes 24 mesocosms mimicking shallow lakes, which at the time of our experiment had run without interruption for 11 years. The 1-month heat wave effect was simulated by increasing the temperature by 5 °C (1 July to 1 August) in A2 and A2+, while A0 was not additionally heated. Throughout the study, HN treatments were mostly dominated by Cyanobacteria, whereas LN treatments were richer in genera and mostly dominated by Chlorophyta. Linear mixed model analyses revealed that high nutrient conditions were the most important structuring factor, which, regardless of temperature treatments and heat waves, increased total phytoplankton, Chlorophyta, Bacillariophyta, and Cyanobacteria biomasses and decreased genus richness and the grazing pressure of zooplankton. The effect of temperature was, however, modest. The effect of warming on the phytoplankton community was not significant before the heat wave, yet during the heat wave it became significant, especially in LN-A2+, and negative interaction effects between nutrient and A2+ warming were recorded. These warming effects continued after the heat wave, as also evidenced by Co-inertia analyses. In contrast to the prevailing theory stating that more diverse ecosystems would be more stable, HN were less affected by the heat wave disturbance, most likely because the dominant phytoplankton group cyanobacteria is adapted to high nutrient conditions and also benefits from increased temperature. We did not find any significant change in phytoplankton size diversity, but size evenness decreased in HN as a result of an increase in the smallest and largest size classes simultaneously. We conclude that the phytoplankton community was most strongly affected by the nutrient level, but less sensitive to changes in both temperature treatments and the heat wave simulation in these systems, which have been adapted for a long time to different temperatures. Moreover, the temperature and heat wave effects were observed mostly in LN systems, indicating that the sensitivity of phytoplankton community structure to high temperatures is dependent on nutrient availability. Full article

(This article belongs to the Special Issue Effect of Extreme Climate Events on Lake Ecosystems)

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21 pages, 6624 KiB

Open AccessEditor’s ChoiceArticle

Trend Analysis of Nitrate Concentration in Rivers in Southern France

by Fayçal Bouraoui and Anna Malagó

Water 2020, 12(12), 3374; https://doi.org/10.3390/w12123374 - 1 Dec 2020

Cited by 4 | Viewed by 3675

Abstract

Excessive nutrients in rivers, lakes and aquifers are still threatening environmental health in Europe. Stringent regulations have led to progress in water quality, however hotspots with high nitrate concentrations still exist in Europe and understanding the impact of management on the nitrate concentrations [...] Read more.

Excessive nutrients in rivers, lakes and aquifers are still threatening environmental health in Europe. Stringent regulations have led to progress in water quality, however hotspots with high nitrate concentrations still exist in Europe and understanding the impact of management on the nitrate concentrations and trends in these critical areas is still challenging. In this paper, we use the Exploration and Graphics for RivEr Trends (EGRET) statistical tool to eliminate the impact of flow variation, both short- and long-term, on nitrate concentration. We apply this tool to the south of France where water quality and quantity monitoring data is readily available. We compare the Mann–Kendall non-parametric approach to estimate trend and a methodology commonly used by Member States of the European Union when they report their progress in implementing the Nitrates Directive (referred to MSD approach hereafter). We showed that using the latter approach for the period 2008–2015 and the Mann–Kendall test leads to similar results in percentage of stations exhibiting trends, however with a significant disagreement on the stations exhibiting these trends. We further showed that when using flow-weighted nitrate concentrations instead of the simple mean nitrate concentration, the MSD approach results in a significant underestimation of the stations with an increasing trend. We also demonstrated that most of nitrate concentration time series are characterized by a bell-shaped curve with an increase of concentration from 1990 to mid-2000 and then a significant decreasing trend due to the implementation of management measures from mid-2000 to 2017. Most of the significant decreasing nitrate concentration trends are localized in Nitrate Vulnerable Zones that correspond to areas where strict nutrient management is required, highlighting the efficiency of the policy in place. Full article

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

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20 pages, 2763 KiB

Open AccessEditor’s ChoiceReview

Filtration Process and Alternative Filter Media Material in Water Treatment

by Anna Cescon and Jia-Qian Jiang

Water 2020, 12(12), 3377; https://doi.org/10.3390/w12123377 - 1 Dec 2020

Cited by 122 | Viewed by 102514

Abstract

In drinking water treatment, filtration plays an important role in the multi-barrier approach employed for the removal of pathogens. The presence of suspended solids and other particulate matter in water increases the resistance of most microbes to disinfection. Therefore, high performance in the [...] Read more.

In drinking water treatment, filtration plays an important role in the multi-barrier approach employed for the removal of pathogens. The presence of suspended solids and other particulate matter in water increases the resistance of most microbes to disinfection. Therefore, high performance in the removal of particles achieved by granular filtration can increase the disinfection efficiency. Although sand is one of the major filter media, alternative media have been developed and used in recent years. In this review, the performance of alternative media is compared with traditional sand/anthracite for drinking water treatment. Advantages in the use of alternative media, especially glass media, have been found, including high filtration performance in removing residual particles and turbidity, minor modification requirements to the existing filtration configuration and slow head loss development. However, before the employment of them in industry, additional tests are recommended. In particular, full scale tests with variations in the operating conditions and analyses of pathogen removal should be performed. Moreover, this paper reviews the filtration processes and operating configurations which provide overall references to those who are studying and working in the field of water technology and treatment. In this paper, legislations/standards of safe drinking water are summarized as they are the driving force of developing new treatment technologies; mathematical modules for predicting the media filtration performance are briefed. Finally, future work on the application of alternative filter media is recommended. Full article

(This article belongs to the Special Issue Advances in the Technologies for Water and Wastewater Treatment)

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30 pages, 17834 KiB

Open AccessEditor’s ChoiceArticle

Long-Term Changes of Morphodynamics on Little Ice Age Lateral Moraines and the Resulting Sediment Transfer into Mountain Streams in the Upper Kauner Valley, Austria

by Moritz Altmann, Livia Piermattei, Florian Haas, Tobias Heckmann, Fabian Fleischer, Jakob Rom, Sarah Betz-Nutz, Bettina Knoflach, Svenja Müller, Katharina Ramskogler, Madlene Pfeiffer, Florentin Hofmeister, Camillo Ressl and Michael Becht

Water 2020, 12(12), 3375; https://doi.org/10.3390/w12123375 - 1 Dec 2020

Cited by 11 | Viewed by 4271

Abstract

Since the end of the Little Ice Age (LIA), formerly glaciated areas have undergone considerable changes in their morphodynamics due to external forces and system-internal dynamics. Using multi-temporal high-resolution digital elevation models (DEMs) from different remote sensing techniques such as historical digital aerial [...] Read more.

Since the end of the Little Ice Age (LIA), formerly glaciated areas have undergone considerable changes in their morphodynamics due to external forces and system-internal dynamics. Using multi-temporal high-resolution digital elevation models (DEMs) from different remote sensing techniques such as historical digital aerial images and light detection and ranging (LiDAR), and the resulting DEMs of difference (DoD), spatial erosion and accumulation patterns can be analyzed in proglacial areas over several decades. In this study, several morphological sediment budgets of different test sites on lateral moraines and different long-term periods were determined, covering a total period of 49 years. The test sites show high ongoing morphodynamics, and therefore low vegetation development. A decrease as well as an increase of the mean annual erosion volume could be demonstrated at the different test sites. All test sites show a slope–channel coupling and a decrease in the efficiency of sediment transport from slopes to channels. These developments are generally subject to conditions of increasing temperature, decreasing short-term precipitation patterns and increasing runoff from adjacent mountain streams. Finally, the study shows that sediment is still available on the investigated test sites and the paraglacial adjustment process is still in progress even after several decades of deglaciation (~133 years). Full article

(This article belongs to the Special Issue Transformation of Glacial and Periglacial Environments in Mountain Regions)

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20 pages, 5152 KiB

Open AccessEditor’s ChoiceArticle

Time Series Changes in Fish Assemblages and Habitat Structures Caused by Partial Check Dam Removal

by Shigeya Nagayama, Nobuo Ishiyama, Taro Seno, Hideyuki Kawai, Yoichi Kawaguchi, Daisuke Nakano and Futoshi Nakamura

Water 2020, 12(12), 3357; https://doi.org/10.3390/w12123357 - 30 Nov 2020

Cited by 10 | Viewed by 3083

Abstract

Despite a steep increase in dam removal projects, there are few studies on the biophysical responses to dam removal. In this study, we evaluated the short-term (1.5 years) and long-term (5.5 years) effects of partial check dam removal on fish assemblages and their [...] Read more.

Despite a steep increase in dam removal projects, there are few studies on the biophysical responses to dam removal. In this study, we evaluated the short-term (1.5 years) and long-term (5.5 years) effects of partial check dam removal on fish assemblages and their habitats. First, the habitat preferences of fish were examined at a channel unit scale: pools, rapids, and side channels satisfied the seasonal habitat requirements of the fish assemblages. Partial check dam removal increased the abundance of these habitats and diversified the habitat structures owing to the sediment release from the dam; in contrast, the bedrock distinctly decreased 1.5 years after dam removal. However, 5.5 years after dam removal, the bedrock proportion increased, and the habitat structures were simplified again owing to the re-transportation of sediments. Similar temporal changes were also determined through a reach-scale analysis with a change in the bed materials. Anadromous Oncorhynchus masou began to spawn and recolonize in the upstream section of the dam after the dam removal, causing similar assemblage compositions between the downstream and upstream sections. The abundance of Salvelinus malma and Noemacheilus barbatulus toni in the upstream reaches decreased over time after the dam removal. The temporal changes in the biophysical responses suggest that long-term monitoring is indispensable for the reliable evaluation of dam removal effects. Full article

(This article belongs to the Special Issue Endangered Freshwater Ecosystems: Threats and Conservation Needs)

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19 pages, 2311 KiB

Open AccessEditor’s ChoiceArticle

The Role of Water Supply Development in the Earth System

by Slobodan P. Simonovic and Patrick A. Breach

Water 2020, 12(12), 3349; https://doi.org/10.3390/w12123349 - 29 Nov 2020

Cited by 14 | Viewed by 3665

Abstract

The ANEMI model is an integrated assessment model of global change that emphasizes the role of water resources. Securing water resources for the future is a key issue of global change and ties into global systems of population growth, climate change carbon cycle, [...] Read more.

The ANEMI model is an integrated assessment model of global change that emphasizes the role of water resources. Securing water resources for the future is a key issue of global change and ties into global systems of population growth, climate change carbon cycle, hydrologic cycle, economy, energy production, land use and pollution generation. The focus of the presented work is on the development of global water supplies necessary to keep pace with a growing population and global economy. With the structure of the ANEMI model, a series of experiments are conducted in order to assess: (i) the current role of water supply in the global Earth system; (ii) the level of water stress that can be expected in the future; and (iii) what are the potential effects of water quality on global surface water supply and the distribution of water supply types. The results of model simulations show that surface water resources were sufficient to meet the water demand and water quality is not shown to be a significant factor for the development of surface water supplies. Due to globally aggregated scale, these impacts are averaged and likely understated. Full article

(This article belongs to the Special Issue Feature Papers of Water Resources Management, Policy and Governance)

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7 pages, 236 KiB

Open AccessEditor’s ChoiceReview

Mycobacterium avium Complex (MAC) in Water Distribution Systems and Household Plumbing in the United States

by Joseph O. Falkinham III

Water 2020, 12(12), 3338; https://doi.org/10.3390/w12123338 - 28 Nov 2020

Cited by 1 | Viewed by 4689

Abstract

Members of the Mycobacterium avium complex (MAC) are waterborne, opportunistic pathogens whose characteristics make urban water distribution systems and household plumbing ideal habitats for their survival, persistence and growth. Rather than contaminants, MAC are colonists of drinking water systems. MAC are normal inhabitants [...] Read more.

Members of the Mycobacterium avium complex (MAC) are waterborne, opportunistic pathogens whose characteristics make urban water distribution systems and household plumbing ideal habitats for their survival, persistence and growth. Rather than contaminants, MAC are colonists of drinking water systems. MAC are normal inhabitants of natural soils and water, and enter drinking water treatment systems through surface sources. A proportion of MAC survive transmission through the treatment plant, and regrow in the distribution system and household plumbing. Once within household plumbing, MAC adhere to surfaces and form biofilms, thus preventing their washout. The thermal tolerance of MAC leads to growth in water heating systems. Stagnation does not reduce MAC numbers, as MAC can grow at low oxygen levels. MAC present challenges to current water monitoring approaches as their numbers do not correlate with E. coli, fecal coliforms or heterotrophic plate count bacteria. Full article

(This article belongs to the Special Issue Dynamic and Diversity of Waterborne Pathogens and Fecal Indicators in Urban Surface Waters)

14 pages, 2432 KiB

Open AccessEditor’s ChoiceArticle

Distributions of Microplastics in Surface Water, Fish, and Sediment in the Vicinity of a Sewage Treatment Plant

by Tae-Jin Park, Seung-Hyun Lee, Myung-Sung Lee, Jae-Kwan Lee, Ji-Hyoung Park and Kyung-Duk Zoh

Water 2020, 12(12), 3333; https://doi.org/10.3390/w12123333 - 27 Nov 2020

Cited by 71 | Viewed by 9152

Abstract

Microplastics are ubiquitously found in freshwater and marine environments worldwide. In particular, wastewater treatment plants (WWTPs) or sewage treatment plants (STPs) have been recognized as a main source of microplastics in the receiving freshwater. However, only a few studies have been conducted to [...] Read more.

Microplastics are ubiquitously found in freshwater and marine environments worldwide. In particular, wastewater treatment plants (WWTPs) or sewage treatment plants (STPs) have been recognized as a main source of microplastics in the receiving freshwater. However, only a few studies have been conducted to examine the impact of these facilities on receiving waters. In this study, we investigated the distribution of microplastics in surface water, fish, and sediment near a sewage treatment plant (STP) in the Tanchon stream, one of the main tributaries flowing into the Han River, Korea. The concentration of microplastics in water varied spatially and temporarily, ranging between 5.3 and 87.3 particles/m³ (31.4 ± 28.5 particles/m³). In fish, the concentration in upstream and downstream sites was 7.3 ± 7.3 and 12.4 ± 17.9 particles/fish, respectively. Spatially, the downstream site was the most polluted with microplastics in water and fish. The concentration of microplastics was positively correlated with fish body length and weight. In sediment, microplastic concentration in upstream and downstream sites was 493.1 ± 136.0 and 380.0 ± 144.2 particles/kg, respectively. The contribution of upstream to the microplastic load in downstream was 15.8% in dry season (April), which was higher than that of STP effluent and Yangjaechon creek. Meanwhile, the highest load was observed in STP effluent (5.1%) in rainy season (August). Microplastics were more abundant in water in the rainy season (37.4 ± 37.0 particles/m³) than in the dry season (28.2 ± 22.2 particles/m³). Polyethylene (49%) and polypropylene (18%) were the most abundant polymer types in water, fish, and sediment. Regarding shape of microplastics, fragments were dominant (95%) over fiber and film in water, fish, and sediment. Full article

(This article belongs to the Special Issue Microplastics in Aquatic Environments and Wastewater Treatment )

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24 pages, 3514 KiB

Open AccessEditor’s ChoiceArticle

Selection of Macroinvertebrate Indices and Metrics for Assessing Sediment Quality in the St. Lawrence River (QC, Canada)

by Mélanie Desrosiers, Bernadette Pinel-Alloul and Charlotte Spilmont

Water 2020, 12(12), 3335; https://doi.org/10.3390/w12123335 - 27 Nov 2020

Cited by 5 | Viewed by 3412

Abstract

This study aims to evaluate the anthropogenic pressure in the St. Lawrence River by assessing the relationships between composition and chemical contamination of sediments and macroinvertebrate community structure using a selection of indices and metrics. The aims of this study are to (i) [...] Read more.

This study aims to evaluate the anthropogenic pressure in the St. Lawrence River by assessing the relationships between composition and chemical contamination of sediments and macroinvertebrate community structure using a selection of indices and metrics. The aims of this study are to (i) determine the composition of macroinvertebrate community in sediments across a gradient of disturbance, (ii) select relevant macroinvertebrate indices and metrics for the assessment of sediment quality, (iii) investigate whether responses of selected indices and metrics differ across habitats and/or sediment quality classes, and finally, (iv) determine the thresholds for critical contaminants related to significant changes in the most relevant indices and metrics. Organic and inorganic contaminants as well as other sediment variables (sediment grain size, total organic carbon, nutrients, etc.) and macroinvertebrate assemblages were determined in 59 sites along the river. Fourteen macroinvertebrate indices and metrics, on the 264 initially selected, were shown to be the most effective to be used in bioassessment for the St. Lawrence River. However, the variation in macroinvertebrate indices and metrics remains strongly explained by habitat characteristics, such as sediment grain size or the level of nutrients. There is also an influence of metals and, to a lesser extent, organic contaminants such as petroleum hydrocarbons. The 14 selected indices and metrics are promising bioassessment tools that are easy to use and interpret in an environmental assessment of sediment quality in the St. Lawrence River. Full article

(This article belongs to the Special Issue Freshwater Macroinvertebrates: Main Gaps and Future Trends)

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25 pages, 3797 KiB

Open AccessEditor’s ChoiceArticle

Advancing Collaborative Water Governance: Unravelling Stakeholders’ Relationships and Influences in Contentious River Basins

by Rodrigo Rojas, Gabriella Bennison, Victor Gálvez, Edmundo Claro and Gabriel Castelblanco

Water 2020, 12(12), 3316; https://doi.org/10.3390/w12123316 - 26 Nov 2020

Cited by 42 | Viewed by 7164

Abstract

Collaborative water governance (CWG) has emerged as a promising framework to tackle water management challenges. Simple identification of participants however is not enough to unravel the intricacies of stakeholders’ interlinkages, roles and influences for robust CWG. A clear understanding of the stakeholders’ landscape [...] Read more.

Collaborative water governance (CWG) has emerged as a promising framework to tackle water management challenges. Simple identification of participants however is not enough to unravel the intricacies of stakeholders’ interlinkages, roles and influences for robust CWG. A clear understanding of the stakeholders’ landscape is therefore required to underpin CWG. In this work, we combine stakeholder analysis (SA), social network analysis (SNA) and participatory processes (PP) under a theoretical collaborative governance framework to advance CWG in the contentious Rapel River Basin (RRB), Chile. By combining these techniques, we identified a cohort of leading (and secondary) stakeholders, their relationships and critical roles on basin-wide CWG-enabling networks (collaborative ties, information flows and financial exchanges) and their influence to achieve a shared vision for water planning. The results show members of this cohort perform critical roles (bridging, connecting and gatekeeping) across the networks and in influencing explicit elements of the shared vision. Specific CWG-enabling networks properties indicate a weak adaptive capacity of stakeholders to deal with potential water management challenges and strong prospects for sharing innovative ideas/solutions and achieving long-term water planning goals. A major CWG implementation challenge in the RRB is the lack of a leading organisation. One way forward would be formally organising stakeholders of the identified cohort to advance CWG in the RRB. By implementing the methodological framework, we facilitated social learning, fostered trust among stakeholders and mobilised efforts towards implementing CWG in practice in the contentious RRB. Full article

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

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20 pages, 4251 KiB

Open AccessEditor’s ChoiceArticle

Seasonal Distributions of Phytoplankton and Environmental Factors Generate Algal Blooms in the Taehwa River, South Korea

by Bo-Ram Sim, Hyung-Chul Kim, Chung-Sook Kim, Jin-Ho Kim, Kyung-Woo Park, Weol-Ae Lim and Won-Chan Lee

Water 2020, 12(12), 3329; https://doi.org/10.3390/w12123329 - 26 Nov 2020

Cited by 12 | Viewed by 3569

Abstract

Algal blooms have occurred in the Taehwa River estuary in South Korea despite the improvement of water quality since environmental renewal projects in the 1990s. In this study, we investigated the causes of algal blooms by measuring the water retention time using a [...] Read more.

Algal blooms have occurred in the Taehwa River estuary in South Korea despite the improvement of water quality since environmental renewal projects in the 1990s. In this study, we investigated the causes of algal blooms by measuring the water retention time using a floating buoy, water quality parameters, and phytoplankton distribution data from 2012. An algal bloom did not occur in February because of phosphate limitations in the Taehwa River estuary; however, the concentration of nutrients in the water inflow from the basin triggered a significant algal bloom in the upper estuary in the month of May. In this regard, the phytoplankton population was dominated by nano- and pico-sized flagellates. In August, the freshwater inflow into the estuary greatly increased due to heavy rainfall, resulting in a shorter retention time of the water bodies, which seemed to prevent an algal bloom. In November, a bloom of Cryptophyceae occurred at one of the sites (the U2 site) due to sufficient nutrients in the water and the long retention times of the water bodies. Our results indicate that a decrease in the nutrients (N and P) supplied from the basin is required for a reduction in algal blooms in the Taehwa River estuary. Additional studies are needed to further elucidate the effects of the land-based, nutrient-rich pollutants flowing into the Taehwa River estuary on algal bloom generation considering the fact that the streams have different environmental characteristics. Full article

(This article belongs to the Special Issue The Ecological Assessment of Rivers and Estuaries: Present and Future)

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23 pages, 8535 KiB

Open AccessEditor’s ChoiceArticle

Monitoring the Hydrological Balance of a Landslide-Prone Slope Covered by Pyroclastic Deposits over Limestone Fractured Bedrock

by Pasquale Marino, Luca Comegna, Emilia Damiano, Lucio Olivares and Roberto Greco

Water 2020, 12(12), 3309; https://doi.org/10.3390/w12123309 - 25 Nov 2020

Cited by 18 | Viewed by 3318

Abstract

Many mountainous areas in Campania, Southern Italy, are characterized by steep slopes covered by loose unsaturated pyroclastic deposits laying upon fractured limestone bedrock. The soil covers are mainly constituted by layers of ashes and pumices. Large and intense rainfall events trigger shallow landslides, [...] Read more.

Many mountainous areas in Campania, Southern Italy, are characterized by steep slopes covered by loose unsaturated pyroclastic deposits laying upon fractured limestone bedrock. The soil covers are mainly constituted by layers of ashes and pumices. Large and intense rainfall events trigger shallow landslides, often turning into debris flows that cause huge damage and casualties. The slope of Cervinara, around 40 km Northeast of Naples, was involved in a catastrophic flowslide on 16 December 1999, triggered by a rainstorm of 325 mm in 48 h. To capture the main effects of precipitation on the slope stability, hydro-meteorological monitoring activities have been carried out at the slope to assess the water balance for three years (2017–2020). The field monitoring data allowed the identification of the complex hydrological processes involving the unsaturated pyroclastic soil and the shallow groundwater system developing in the limestone bedrock, which control the conditions that potentially predispose the slope to landslide triggering. Specifically, late autumn has been identified as the potentially most critical period, when slope drainage processes are not yet effective, and soil covers already receive large amounts of precipitation. Full article

(This article belongs to the Special Issue Rainfall Infiltration Processes and Their Effects on Landslide Hazard)

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17 pages, 529 KiB

Open AccessEditor’s ChoiceReview

Antimicrobials and Antibiotic-Resistant Bacteria: A Risk to the Environment and to Public Health

by Liliana Serwecińska

Water 2020, 12(12), 3313; https://doi.org/10.3390/w12123313 - 25 Nov 2020

Cited by 571 | Viewed by 52073

Abstract

The release of antibiotics to the environment, and the consequences of the presence of persistent antimicrobial residues in ecosystems, have been the subject of numerous studies in all parts of the world. The overuse and misuse of antibiotics is a common global phenomenon, [...] Read more.

The release of antibiotics to the environment, and the consequences of the presence of persistent antimicrobial residues in ecosystems, have been the subject of numerous studies in all parts of the world. The overuse and misuse of antibiotics is a common global phenomenon, which substantially increases the levels of antibiotics in the environment and the rates of their spread. Today, it can be said with certainty that the mass production and use of antibiotics for purposes other than medical treatment has an impact on both the environment and human health. This review aims to track the pathways of the environmental distribution of antimicrobials and identify the biological effects of their subinhibitory concentration in different environmental compartments; it also assesses the associated public health risk and government policy interventions needed to ensure the effectiveness of existing antimicrobials. The recent surge in interest in this issue has been driven by the dramatic increase in the number of infections caused by drug-resistant bacteria worldwide. Our study is in line with the global One Health approach. Full article

(This article belongs to the Special Issue Application of Ecohydrology Approach for Mitigation of Freshwater Ecosystems Contamination)

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30 pages, 12064 KiB

Open AccessEditor’s ChoiceArticle

Modeling of Mass Balance Variability and Its Impact on Water Discharge from the Urumqi Glacier No. 1 Catchment, Tian Shan, China

by Kira Thiel, Anselm Arndt, Puyu Wang, Huilin Li, Zhongqin Li and Christoph Schneider

Water 2020, 12(12), 3297; https://doi.org/10.3390/w12123297 - 24 Nov 2020

Cited by 6 | Viewed by 4314

Abstract

Originating in the Tian Shan mountains, Urumqi River plays a key role in terms of water supply to downstream areas. In its headwaters, Urumqi Glacier No. 1 (UG1) is the largest glacier contributing to water discharge. Assessing its response to the changing climatic [...] Read more.

Originating in the Tian Shan mountains, Urumqi River plays a key role in terms of water supply to downstream areas. In its headwaters, Urumqi Glacier No. 1 (UG1) is the largest glacier contributing to water discharge. Assessing its response to the changing climatic conditions in the area is of major importance to quantify future water availability. We here apply COSIPY, a COupled Snowpack and Ice surface energy and mass balance model in PYthon, to UG1, implementing a new albedo parameterization which integrates site-specific bare-ice albedo values on a pixel-by-pixel basis observed by remote sensing. We assess model performance threefold: quantitatively based on long-term measurement data of (1) surface mass balance (SMB) and (2) water discharge as well as qualitatively (3) comparing simulated snow line altitudes to such imated on the basis of time-lapse photography. Comparison of the modeled SMB with annually-averaged data from ablation stakes reveals that COSIPY including the new albedo parameterization accounts for 57.6% of the variance observed in the measurements. The original albedo parameterization performs only slightly inferior (57.1%). Glacier-wide comparison between modeled and glaciological SMB shows high agreement. In terms of discharge prediction, COSIPY reproduces onset and duration of the discharge season well. Estimated discharge from the whole catchment shows shortcomings in exactly matching the measured times series, but interannual variability is captured. Full article

(This article belongs to the Special Issue Transformation of Glacial and Periglacial Environments in Mountain Regions)

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16 pages, 4724 KiB

Open AccessEditor’s ChoiceArticle

Variations in Soil Erosion Resistance of Gully Head Along a 25-Year Revegetation Age on the Loess Plateau

by Zhuoxin Chen, Mingming Guo and Wenlong Wang

Water 2020, 12(12), 3301; https://doi.org/10.3390/w12123301 - 24 Nov 2020

Cited by 20 | Viewed by 2842

Abstract

The effects of vegetation restoration on soil erosion resistance of gully head, along a revegetation age gradient, remain poorly understood. Hence, we collected undisturbed soil samples from a slope farmland and four grasslands with different revegetation ages (3, 10, 18, 25 years) along [...] Read more.

The effects of vegetation restoration on soil erosion resistance of gully head, along a revegetation age gradient, remain poorly understood. Hence, we collected undisturbed soil samples from a slope farmland and four grasslands with different revegetation ages (3, 10, 18, 25 years) along gully heads. Then, these samples were used to obtain soil detachment rate of gully heads by the hydraulic flume experiment under five unit width flow discharges (2–6 m³ h). The results revealed that soil properties were significantly ameliorated and root density obviously increased in response to restoration age. Compared with farmland, soil detachment rate of revegetated gully heads decreased 35.5% to 66.5%, and the sensitivity of soil erosion of the gully heads to concentrated flow decreased with revegetation age. The soil detachment rate of gully heads was significantly related to the soil bulk density, soil disintegration rate, capillary porosity, saturated soil hydraulic conductivity, organic matter content and water stable aggregate. The roots of 0–0.5 and 0.5–1.0 mm had the highest benefit in reducing soil loss of gully head. After revegetation, soil erodibility of gully heads decreased 31.0% to 78.6%, and critical shear stress was improved by 1.2 to 4.0 times. The soil erodibility and critical shear stress would reach a stable state after an 18-years revegetation age. These results allow us to better evaluate soil vulnerability of gully heads to concentrated flow erosion and the efficiency of revegetation. Full article

(This article belongs to the Special Issue Soil–Water Conservation, Erosion, and Landslide)

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15 pages, 1518 KiB

Open AccessEditor’s ChoiceArticle

The Adsorption Selectivity of Short and Long Per- and Polyfluoroalkyl Substances (PFASs) from Surface Water Using Powder-Activated Carbon

by Heejong Son, Taehoon Kim, Hoon-Sik Yoom, Dongye Zhao and Byungryul An

Water 2020, 12(11), 3287; https://doi.org/10.3390/w12113287 - 23 Nov 2020

Cited by 74 | Viewed by 7292

Abstract

Nine per- and polyfluoroalkyl substances (PFASs), including six perfluoroalkyl carboxylic acids (PFCAs) and three perfluoroalkyl sulfonic acids (PFSAs), were tested to find their adsorption selectivity from surface water and the feasibility of the powder activated carbon (PAC) process between the perchlorination and coagulation [...] Read more.

Nine per- and polyfluoroalkyl substances (PFASs), including six perfluoroalkyl carboxylic acids (PFCAs) and three perfluoroalkyl sulfonic acids (PFSAs), were tested to find their adsorption selectivity from surface water and the feasibility of the powder activated carbon (PAC) process between the perchlorination and coagulation processes by operating parameters such as mixing intensity, dosage, contact time, initial pH, and concentration of perchlorination. The removal efficiency of four types of PAC revealed that the coal-based activated carbon was clearly advanced for all of the PFASs, and the thermal regenerated PAC did not exhibit a significant reduction in adsorption capacity. The longer carbon chain or the higher molecular weight (MW) obtained a higher adsorption capacity and the MW exhibited a more proportional relationship with the removal efficiency than the carbon chain number, regardless of the PFCA and PFSA species. Approximately 80% and 90% equilibria were accomplished within 60 and 120 min for the long chain carbon PFAS, respectively, while for the short chain PFAS, 240 min was required to reach 85% equilibrium. The effect of mixing intensity (rpm) was not considered for the removal of the PFAS, although it was relatively influenced in the short PFAS species. Due to the surface charge of the PAC and the properties of protonation of the PFASs, the acid condition increased the PFASs’ adsorption capacity. The prechlorination decreased the removal efficiency, and the reduction rate was more significantly influenced for the short chain PFAS than for the long chain PFAS. Full article

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

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19 pages, 4588 KiB

Open AccessEditor’s ChoiceArticle

Assessing Land-Cover Effects on Stream Water Quality in Metropolitan Areas Using the Water Quality Index

by TaeHo Kim, YoungWoo Kim, Jihoon Shin, ByeongGeon Go and YoonKyung Cha

Water 2020, 12(11), 3294; https://doi.org/10.3390/w12113294 - 23 Nov 2020

Cited by 12 | Viewed by 7370

Abstract

This study evaluated the influence of different land-cover types on the overall water quality of streams in urban areas. To ensure national applicability of the results, this study encompassed ten major metropolitan areas in South Korea. Using cluster analysis, watersheds were classified into [...] Read more.

This study evaluated the influence of different land-cover types on the overall water quality of streams in urban areas. To ensure national applicability of the results, this study encompassed ten major metropolitan areas in South Korea. Using cluster analysis, watersheds were classified into three land-cover types: Urban-dominated (URB), agriculture-dominated (AGR), and forest-dominated (FOR). For each land-cover type, factor analysis (FA) was used to ensure simple and feasible parameter selection for developing the minimum water quality index (WQI_min). The chemical oxygen demand, fecal coliform (total coliform for FOR), and total nitrogen (nitrate-nitrogen for URB) were selected as key parameters for all land-cover types. Our results suggest that WQI_min can minimize bias in water quality assessment by reducing redundancy among correlated parameters, resulting in better differentiation of pollution levels. Furthermore, the dominant land-cover type of watersheds, not only affects the level and causes of pollution, but also influences temporal patterns, including the long-term trends and seasonality, of stream water quality in urban areas in South Korea. Full article

(This article belongs to the Special Issue Assessing Water Quality by Statistical Methods)

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18 pages, 6356 KiB

Open AccessEditor’s ChoiceArticle

Integrated Taxonomy for Halistemma Species from the Northwest Pacific Ocean

by Nayeon Park, Andrey A. Prudkovsky and Wonchoel Lee

Water 2020, 12(11), 3283; https://doi.org/10.3390/w12113283 - 22 Nov 2020

Cited by 2 | Viewed by 3543

Abstract

During a survey of the siphonophore community in the Kuroshio Extension, Northwest Pacific Ocean, a new Halistemma Huxley, 1859 was described using integrated molecular and morphological approaches. The Halistemma isabu sp. nov. nectophore is most closely related morphologically to H. striata Totton, [...] Read more.

During a survey of the siphonophore community in the Kuroshio Extension, Northwest Pacific Ocean, a new Halistemma Huxley, 1859 was described using integrated molecular and morphological approaches. The Halistemma isabu sp. nov. nectophore is most closely related morphologically to H. striata Totton, 1965 and H. maculatum Pugh and Baxter, 2014. These species can be differentiated by their nectosac shape, thrust block size, ectodermal cell patches and ridge patterns. The new species’ bracts are divided into two distinct types according to the number of teeth. Type A bracts are more closely related to ventral bracts in H. foliacea (Quoy and Gaimard, 1833) while Type B bracts are more similar to H. rubrum (Vogt, 1852). Each type differs, however, from the proximal end shape, distal process and bracteal canal. Both of the new species’ morphological type and phylogenetic position within the genus Halistemma are supported by phylogenetic analysis of concatenated DNA dataset (mtCOI, 16S rRNA and 18S rRNA). Integrated morphological and molecular approaches to the taxonomy of siphonophores showed a clear delimitation of the new species from the congeners. Halistemma isabu sp. nov. is distributed with the congeners H. rubrum, H. cupulifera, H. foliacea and H. striata in the northwestern Pacific Ocean. Full article

(This article belongs to the Special Issue Species Richness and Diversity of Aquatic Ecosystems)

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13 pages, 1286 KiB

Open AccessEditor’s ChoiceArticle

Factors Influencing Abundances and Population Size Structure of the Threatened and Endemic Cyprinodont Aphanius iberus in Mediterranean Brackish Ponds

by Serena Sgarzi, Sandra Brucet, Mireia Bartrons, Ignasi Arranz, Lluís Benejam and Anna Badosa

Water 2020, 12(11), 3264; https://doi.org/10.3390/w12113264 - 21 Nov 2020

Cited by 5 | Viewed by 3878

Abstract

Aphanius iberus is an endemic cyprinodontoid fish species of Mediterranean ponds in danger of extinction. In this study, we studied some abiotic and biotic factors that can influence A. iberus’s size structure and density in Mediterranean brackish ponds. We sampled fish using [...] Read more.

Aphanius iberus is an endemic cyprinodontoid fish species of Mediterranean ponds in danger of extinction. In this study, we studied some abiotic and biotic factors that can influence A. iberus’s size structure and density in Mediterranean brackish ponds. We sampled fish using fyke nets in 10 ponds of Empordà (Spain) during the spring season. Our results showed that a better ecological status (according to the Water Quality of Lentic and Shallow Ecosystems (QAELS) index), pond’s depth and pond’s isolation (reflected by an increase in total nitrogen) were related to larger individual sizes and more size-diverse populations. Increasing the salinity is known to help the euryhaline A. iberus acting as a refuge from competitors. Nevertheless, our results showed that higher conductivities had a negative effect on A. iberus’s size structure, leading to a decrease in the mean and maximum size of the fish. Fish abundance (expressed as captures per unit of effort (CPUE)) seemed to increase with increasing the pond’s depth and total nitrogen (the latter reflecting pond isolation). In conclusion, our results suggest that achieving a better pond ecological status may be important for the conservation of endangered A. iberus, because better size-structured populations (i.e., larger mean and average lengths) were found at higher water quality conditions. Full article

(This article belongs to the Special Issue Ecology and Conservation of Freshwater Fishes Biodiversity)

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20 pages, 5200 KiB

Open AccessEditor’s ChoiceArticle

Climate Change Impact on Hydropower Resources in Gauged and Ungauged Lithuanian River Catchments

by Darius Jakimavičius, Gintaras Adžgauskas, Diana Šarauskienė and Jūratė Kriaučiūnienė

Water 2020, 12(11), 3265; https://doi.org/10.3390/w12113265 - 21 Nov 2020

Cited by 14 | Viewed by 3930

Abstract

Hydropower (potential and kinetic energy) is one of the most important renewable energy sources in the world. This energy is directly dependent on water resources and the hydrological cycle. Ongoing climate changes are likely to influence the availability/amount of this energy resource. The [...] Read more.

Hydropower (potential and kinetic energy) is one of the most important renewable energy sources in the world. This energy is directly dependent on water resources and the hydrological cycle. Ongoing climate changes are likely to influence the availability/amount of this energy resource. The present study explores the relationship between climate changes and river runoff, projects future runoff in both gauged and ungauged river catchments, and then assesses how these alterations may affect the future hydropower resources in Lithuania. Runoff projections of the gauged rivers were evaluated applying Swedish Department of Climate hydrological model, and runoff of ungauged river catchments were estimated by created isoline maps of specific runoff. According to an ensemble of three climate models and two Representative Concentration Pathway scenarios, runoff and hydroelectric energy projections were evaluated for two future periods (2021–2040, 2081–2100). The results demonstrated a decrease in future river runoff. Especially significant changes are expected according to the most pessimistic RCP8.5 scenario at the end of the century. The projected changes are likely to bring a negative effect on hydropower production in the country. These findings could help understand what kind of benefits and challenges water resource managers may face in the future. Full article

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31 pages, 5407 KiB

Open AccessEditor’s ChoiceArticle

The Impacts of Climate Change on Wastewater Treatment Costs: Evidence from the Wastewater Sector in China

by Ami Reznik, Yu Jiang and Ariel Dinar

Water 2020, 12(11), 3272; https://doi.org/10.3390/w12113272 - 21 Nov 2020

Cited by 12 | Viewed by 5690

Abstract

Treatment of wastewater is expected to become a major development issue in the years to come. We investigate the relationship between climate and costs of wastewater treatment with the objective of examining if changes in climate might have an impact on the costs [...] Read more.

Treatment of wastewater is expected to become a major development issue in the years to come. We investigate the relationship between climate and costs of wastewater treatment with the objective of examining if changes in climate might have an impact on the costs of wastewater treatment. For that purpose, we use a cross-section sample of 163 treatment plants from China to estimate the industry’s cost function. The methodology used comprises an econometric estimation procedure of treatment costs of the wastewater sector, and a simulation of changes in these costs predicted with future climate conditions, policy implementation scenarios, population growth and development trends. Our results find evidence of climate change impact on treatment costs. We also simulate potential impact of future policy and climate scenarios on costs of treatment, and we measure the cost impact of all other cost determinants but climate—as these are indirectly affected by accounting for climate in the estimation procedure. This indirect impact predicts total cost changes of different magnitudes across the range of future scenarios investigated. Full article

(This article belongs to the Special Issue Water Management: New Paradigms for Water Treatment and Reuse)

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20 pages, 5385 KiB

Open AccessEditor’s ChoiceArticle

Floating Wetland Islands Implementation and Biodiversity Assessment in a Port Marina

by Cristina S. C. Calheiros, João Carecho, Maria P. Tomasino, C. Marisa R. Almeida and Ana P. Mucha

Water 2020, 12(11), 3273; https://doi.org/10.3390/w12113273 - 21 Nov 2020

Cited by 12 | Viewed by 8108

Abstract

Floating wetland islands (FWI) are considered nature-based solutions with great potential to promote several ecosystem services, such as biodiversity and water quality enhancement through phytoremediation processes. To our knowledge, the present work is the first to scientifically document the in-situ establishment of an [...] Read more.

Floating wetland islands (FWI) are considered nature-based solutions with great potential to promote several ecosystem services, such as biodiversity and water quality enhancement through phytoremediation processes. To our knowledge, the present work is the first to scientifically document the in-situ establishment of an FWI in a seawater port marina. The establishment and performance of a cork floating platform with a polyculture (Sarcocornia perennis, Juncus maritimus, Phragmites australis, Halimione portulacoides, Spartina maritima, Limonium vulgare) was evaluated. The diversity of organisms present in the FWI was undertaken based on the macrofauna assessment, taking into consideration marine water characterization, with a focus on hydrocarbons. Microbial communities were assessed based on metabarcoding approach to study 16S rRNA gene from environmental DNA retrieved from biofilm (from the planting media), marine biofouling (from the submerged platform) and surface marina water. S. perennis was the species with the highest survival rate and growth. The structure of the microbial community showed clear differences between those established in the FWI and those in the surrounding water, showing the presence of some bacterial groups that can be relevant for bioremediation processes (e.g., Saprospiraceae family). Concerning the macrofauna analysis, Mytilus sp. was the predominant taxa. To be of relevance, total petroleum hydrocarbons were detected at the marina up to ca. 6 mg/L. This study gives new insights into broadening FWI application to the saline environments of port marinas and to supporting a management strategy to promote several ecosystem services such biodiversity, species habitat, water quality enhancement and added aesthetic value to the marina landscape. Full article

(This article belongs to the Special Issue Water Management: New Paradigms for Water Treatment and Reuse)

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20 pages, 3649 KiB

Open AccessEditor’s ChoiceArticle

Variability in Environmental Conditions Strongly Impacts Ostracod Assemblages of Lowland Springs in a Heavily Anthropized Area

by Giampaolo Rossetti, Valentina Pieri, Rossano Bolpagni, Daniele Nizzoli and Pierluigi Viaroli

Water 2020, 12(11), 3276; https://doi.org/10.3390/w12113276 - 21 Nov 2020

Cited by 5 | Viewed by 3586

Abstract

The Po river plain (Northern Italy) hosts artificial, lowland springs locally known as fontanili, which provide important ecosystem services in an area dominated by intensive agricultural activities. Here we present a study carried out in 50 springs. Each spring was visited once from [...] Read more.

The Po river plain (Northern Italy) hosts artificial, lowland springs locally known as fontanili, which provide important ecosystem services in an area dominated by intensive agricultural activities. Here we present a study carried out in 50 springs. Each spring was visited once from October 2015 to January 2016. The sampled sites were selected to include springs studied in 2001 and 2004, to evaluate changes in water quality and ostracod assemblages that possibly occurred over a period of 10–15 years, and explore the relationships between ostracod community composition and water physical and chemical variables. Our results showed a decrease in the chemical water quality especially, in springs south of the Po river, evidenced by high nitrate levels. Most of the studied springs showed a relevant decrease in dissolved reactive silica, probably related to recent transformations of either agricultural practices or crop typology. Ostracods were mostly represented by common and tolerant species, and communities were characterized by low alpha diversity and high species turnover. Water temperature and mineralization level were the most influential variables in structuring the ostracod communities. We stress the need to implement conservation and restoration measures for these threatened ecosystems, to regain their role as ecosystem services providers. Full article

(This article belongs to the Special Issue Biodiversity and Functionality in Freshwater and Transitional Ecosystems)

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16 pages, 2306 KiB

Open AccessEditor’s ChoiceArticle

Effectiveness of the “Ecological Beach” Model: Beneficial Management of Posidonia Beach Casts and Banquette

by Alice Rotini, Stefania Chiesa, Loredana Manfra, Patrizia Borrello, Raffaella Piermarini, Cecilia Silvestri, Sergio Cappucci, Luca Parlagreco, Saverio Devoti, Marco Pisapia, Carla Creo, Tiziana Mezzetti, Alfonso Scarpato and Luciana Migliore

Water 2020, 12(11), 3238; https://doi.org/10.3390/w12113238 - 19 Nov 2020

Cited by 27 | Viewed by 5896

Abstract

The accumulation of Posidonia oceanica dead leaves on the beaches of the Mediterranean shores is a natural phenomenon. They are either temporary or permanent structures (banquettes) and represent a valuable resource, with important ecosystem functions including coastal protection against erosion. Nevertheless, [...] Read more.

The accumulation of Posidonia oceanica dead leaves on the beaches of the Mediterranean shores is a natural phenomenon. They are either temporary or permanent structures (banquettes) and represent a valuable resource, with important ecosystem functions including coastal protection against erosion. Nevertheless, the perception of these plant accumulations by the different stakeholders (beach managers, local administrations and tourists) is often negative; they consider these deposits a malevolent waste to be removed, rather than a natural and valuable component of the coastline. We propose an integrated/beneficial management model for posidonia deposits, called ECOLOGICAL BEACH, firstly proposed in France, and recently implemented and applied in Italy. The model promotes the preservation of posidonia beach casts on site, with a balanced coexistence of natural and anthropic elements. The model fosters the several important ecosystem services of the beach casts and contributes to coastal preservation. To successfully spread the model, several activities must be implemented: a regulatory framework, the collection of data about the occurrence of beach casts, management protocols and educational programs. The most important activity is the educational one, based on the dissemination of the ecological and economic value of the beach casts, aimed at switching the perception of this phenomenon towards positive appraisal. Full article

(This article belongs to the Special Issue Aquatic Ecosafety: Threats, Disturbances, Environmental Monitors and Bioremediation Actions)

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29 pages, 7286 KiB

Open AccessEditor’s ChoiceArticle

Assessment of the Anthropogenic Sediment Budget of a Littoral Cell System (Northern Tuscany, Italy)

by Sergio Cappucci, Duccio Bertoni, Luigi Enrico Cipriani, Gianfranco Boninsegni and Giovanni Sarti

Water 2020, 12(11), 3240; https://doi.org/10.3390/w12113240 - 19 Nov 2020

Cited by 19 | Viewed by 4161

Abstract

In the present study we describe a straightforward and highly replicable methodology to assess the anthropogenic sediment budget within a coastal system (the Northern Tuscany littoral cell, Italy), specifically selected in a partially natural and partially highly urbanized coastal area, characterized by erosion [...] Read more.

In the present study we describe a straightforward and highly replicable methodology to assess the anthropogenic sediment budget within a coastal system (the Northern Tuscany littoral cell, Italy), specifically selected in a partially natural and partially highly urbanized coastal area, characterized by erosion and accretion processes. The anthropogenic sediment budget has been here calculated as an algebraic sum of sediment inputs, outputs and transfer (m³) within a 40 year time interval (1980–2020). Sediment management strongly influences the sediment budget and, even if its evaluation is crucial to assess the efficiency of a coastal management policy, it is often difficult to quantify the anthropogenic contribution to sedimentary processes. Different types of intervention are carried out by a variety of competent authorities over time (Municipalities, Marinas, Port Authorities), and the correct accountability of sediment budget is no longer known, or possible, for the scientific community. In the Northern Tuscany littoral cell, sedimentation is concentrated in a convergent zone and updrift of port structures, which have determined a series of actions, from offshore dumping and disposal into confined facilities (sediment output), to bypassing and redistribution interventions (sediment transfer); conversely, river mouths and coastal areas protected by groins and barriers are subjected to severe erosion and coastline retreat, resulting in many beach nourishments (sediment input). The majority of coastal protection interventions were carried out to redistribute sand from one site to another within the study area (2,949,800 m³), while the sediment input (1,011,000 m³) almost matched the sediment output (1,254,900 m³) in the considered time interval. A negative anthropogenic sediment budget (−243,900 m³) is here documented. Full article

(This article belongs to the Special Issue Coastal Sediment Management: From Theory to Practice)

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27 pages, 4403 KiB

Open AccessEditor’s ChoiceArticle

A Novel Hybrid Approach for Water Resources Carrying Capacity Assessment by Integrating Fuzzy Comprehensive Evaluation and Analytical Hierarchy Process Methods with the Cloud Model

by Bo Ren, Qiuwen Zhang, Juanhui Ren, Song Ye and Fei Yan

Water 2020, 12(11), 3241; https://doi.org/10.3390/w12113241 - 19 Nov 2020

Cited by 23 | Viewed by 2754

Abstract

The water resources carrying capacity (WRCC) shows remarkable fuzziness and randomness, which causes the uncertainty and instability of the WRCC assessment (WRCCA). In order to solve these problems, we proposed a novel hybrid approach for WRCCA, in which the fuzzy comprehensive evaluation (FCE) [...] Read more.

The water resources carrying capacity (WRCC) shows remarkable fuzziness and randomness, which causes the uncertainty and instability of the WRCC assessment (WRCCA). In order to solve these problems, we proposed a novel hybrid approach for WRCCA, in which the fuzzy comprehensive evaluation (FCE) and analytical hierarchy process (AHP) methods were integrated with the cloud model (CM). Firstly, an evaluation indicator system of WRCC was constructed. Secondly, the AHP and FCE methods were subsequently improved with the CM. The CM was used to scale the relative importance and aggregate the judgment matrices, where the weights of the clouds were obtained. These integrations of AHP and CM greatly reduced the randomness in the weight calculation; the CM was used to describe the comment sets, calculate the membership degree matrices and determine the assignment clouds, the evaluation sets and the WRCCA index clouds were obtained. These integrations of FCE and CM effectively blurred the boundary fuzziness and gave more intuitive results. Finally, the hybrid FCE-AHP-CM approach was applied to a case study. It was concluded that the novel approach has particular advantages in dealing with the fuzziness and randomness comprehensively, and therefore could assess the WRCC and enhance the robustness and intuition of WRCCA results. Full article

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

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25 pages, 7560 KiB

Open AccessEditor’s ChoiceArticle

Swimming Behavior of Downstream Moving Fish at Innovative Curved-Bar Rack Bypass Systems for Fish Protection at Water Intakes

by Claudia Beck, Ismail Albayrak, Julian Meister, Armin Peter, Oliver M. Selz, Claudia Leuch, David F. Vetsch and Robert M. Boes

Water 2020, 12(11), 3244; https://doi.org/10.3390/w12113244 - 19 Nov 2020

Cited by 24 | Viewed by 4132

Abstract

New types of fish guidance structures with vertical curved bars and a subsequent bypass system represent a promising technical solution for the protection and guidance of downstream moving fish at run-of-river hydropower plants and water intakes. These so-called “curved-bar rack bypass systems” (CBR-BSs) [...] Read more.

New types of fish guidance structures with vertical curved bars and a subsequent bypass system represent a promising technical solution for the protection and guidance of downstream moving fish at run-of-river hydropower plants and water intakes. These so-called “curved-bar rack bypass systems” (CBR-BSs) function as a mechanical behavioral barrier and are characterized by low hydraulic losses, a symmetrical downstream flow field and an overall high fish guidance efficiency in the laboratory for a wide array of European freshwater fish species. This paper presents the results of the hydraulic and live-fish laboratory tests of an optimized CBR-BS configuration with a bar spacing of 50 mm and 30° rack angle to the flow direction. The tests were conducted with six different fish species in an ethohydraulic laboratory flume at different approach flows (0.5 m/s, 0.7 m/s) and different bypass entrance velocities (0.6–1.0 m/s). A numerical model was used to simulate the flow fields in the CBR-BS in order to link the fish behavior to the hydrodynamic cues created by the CBR-BS. Lower approach flow velocities decreased the hydraulic cues of the CBR, which led to more rack passages. A 20% velocity increase towards the bypass entrance significantly increased the fish guidance efficiency compared to a 40% velocity increase. The tested CBR-BS resulted in overall higher interspecies fish protection and guidance efficiencies compared to the more commonly applied horizontal-bar rack with a narrow bar spacing of 20 mm. Recommendations for a sustainable and cost-effective application of CBR-BSs are given. Full article

(This article belongs to the Special Issue Fish Passage at Hydropower Dams)

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21 pages, 2765 KiB

Open AccessEditor’s ChoiceArticle

Implications of Nutrient Enrichment and Related Environmental Impacts in the Pearl River Estuary, China: Characterizing the Seasonal Influence of Riverine Input

by Lixia Niu, Pieter van Gelder, Xiangxin Luo, Huayang Cai, Tao Zhang and Qingshu Yang

Water 2020, 12(11), 3245; https://doi.org/10.3390/w12113245 - 19 Nov 2020

Cited by 23 | Viewed by 4011

Abstract

The Pearl River estuary is an ecologically dynamic region located in southern China that experiences strong gradients in its biogeochemical properties. This study examined the seasonality of nutrient dynamics, identified related environmental responses, and evaluated how river discharge regulated nutrient sink and source. [...] Read more.

The Pearl River estuary is an ecologically dynamic region located in southern China that experiences strong gradients in its biogeochemical properties. This study examined the seasonality of nutrient dynamics, identified related environmental responses, and evaluated how river discharge regulated nutrient sink and source. The field investigation showed significant differences of dissolved nutrients with seasons and three zones of the estuary regarding the estuarine characteristics. Spatially, nutrients exhibited a clear decreasing trend along the salinity gradient; temporally, their levels were obviously higher in summer than other seasons. The aquatic environment was overall eutrophic, as a result of increased fluxes of nitrogen and silicate. This estuary was thus highly sensitive to nutrient enrichment and related pollution of eutrophication. River discharge, oceanic current, and atmospheric deposition distinctly influenced the nutrient status. These factors accordingly may influence phytoplankton that are of importance in coastal ecosystems. Phytoplankton (in terms of chlorophyll) was potentially phosphate limited, which then more frequently resulted in nutrient pollution and blooms. Additionally, the nutrient sources were implied according to the cause–effect chains between nutrients, hydrology, and chlorophyll, identified by the PCA-generated quantification. Nitrogen was constrained by marine-riverine waters and their mutual increase-decline trend, and a new source was supplemented along the transport from river to sea, while a different source of terrestrial emission from coastal cities contributed to phosphate greatly. Full article

(This article belongs to the Special Issue Pollution in Estuaries and Coastal Marine Waters)

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19 pages, 1823 KiB

Open AccessEditor’s ChoiceArticle

Dissolved Organic Matter Quality and Biofilm Composition Affect Microbial Organic Matter Uptake in Stream Flumes

by Gabriele Weigelhofer, Tania Sosa Jirón, Tz-Ching Yeh, Gertraud Steniczka and Matthias Pucher

Water 2020, 12(11), 3246; https://doi.org/10.3390/w12113246 - 19 Nov 2020

Cited by 18 | Viewed by 4282

Abstract

Agriculture delivers significant amounts of dissolved organic matter (DOM) to streams, thereby changing the composition and biodegradability of the aquatic DOM. This study focuses on the interactive effects of DOM quality and biofilm composition on the degradation of DOM in a laboratory flume [...] Read more.

Agriculture delivers significant amounts of dissolved organic matter (DOM) to streams, thereby changing the composition and biodegradability of the aquatic DOM. This study focuses on the interactive effects of DOM quality and biofilm composition on the degradation of DOM in a laboratory flume experiment. Half of the flumes were exposed to light to stimulate algal growth, the other half was shaded. Leachates of deciduous leaves, maize leaves, and cow dung were added to the flumes in a single pulse and changes of DOC (dissolved organic carbon) and nutrient concentrations, DOM composition (absorbance and fluorescence data), chlorophyll-a concentrations, bacterial abundances, and enzymatic activities were recorded over a week. DOM was taken up with rates of 50, 109, and 136 µg DOC L⁻¹ h⁻¹ for dung, leaf, and maize leachates, respectively, in the light flumes and 37, 80, and 170 µg DOC L⁻¹ h⁻¹ in the dark flumes. DOC uptake correlated strongly with initial SRP (soluble reactive phosphorus) and DOC concentrations, but barely with DOM components and indices. Algae mostly stimulated the microbial DOC uptake, but the effects differed among differently aged biofilms. We developed a conceptual model of intrinsic (DOM quality) and external (environmental) controlling factors on DOM degradation, with the microbial community acting as biotic filter. Full article

(This article belongs to the Special Issue Transformation of Dissolved Organic Matter in Aquatic Landscapes)

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18 pages, 970 KiB

Open AccessEditor’s ChoiceArticle

Enhancing Water Literacy through an Innovative Television Series Focused on Wai Maoli: Hawai’i Fresh Water Initiative

by Kanesa Duncan Seraphin

Water 2020, 12(11), 3247; https://doi.org/10.3390/w12113247 - 19 Nov 2020

Cited by 3 | Viewed by 2871

Abstract

This study examined the ability of four 30-min television (TV) episodes to affect viewers’ understanding of, and engagement in, fresh water recharge, conservation, and reuse. We used questionnaires to examine changes in viewers’ perceived understanding, interest, and motivation after watching episodes at in-person [...] Read more.

This study examined the ability of four 30-min television (TV) episodes to affect viewers’ understanding of, and engagement in, fresh water recharge, conservation, and reuse. We used questionnaires to examine changes in viewers’ perceived understanding, interest, and motivation after watching episodes at in-person screenings during September 2019 (average 27.5 attendees and 19.5 respondents per episode screening). In general, perception of skills and engagement increased after viewing the episode, and viewers reported a willingness to take action themselves as well as to pledge support for the use of public funds in water-related actions. However, viewers were less swayed on topics such as the “ickiness” of recycled water and on policies that allow black water recycling. At the final screening of the series, we also investigated preference for in-depth content versus a synoptic episode via structured focus groups. With a high degree of consensus, focus group participants felt that topics were better presented in episodes with more in-depth content. These results support the use of long-form, content-rich educational videos to teach water science and increase motivation. In combination with TV viewing metrics, our study thus supports the use of TV as an effective medium for reaching a broad demographic. However, our findings also imply that changing viewers’ perceptions on controversial water-use topics requires additional consideration to support the construction of new beliefs, water literacy, and citizen engagement. Full article

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

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28 pages, 7150 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Impact of Relative Sea-Level Rise on Low-Lying Coastal Areas of Catalonia, NW Mediterranean, Spain

by Uxía López-Dóriga and José A. Jiménez

Water 2020, 12(11), 3252; https://doi.org/10.3390/w12113252 - 19 Nov 2020

Cited by 21 | Viewed by 9901

Abstract

Low-lying coastal areas are high-risk areas regarding sea-level rise (SLR) due to the combination of low elevation, subsidence and currently low sediment supply, on the one hand, and their high natural and socio-economic values, on the other. Because of this, there is a [...] Read more.

Low-lying coastal areas are high-risk areas regarding sea-level rise (SLR) due to the combination of low elevation, subsidence and currently low sediment supply, on the one hand, and their high natural and socio-economic values, on the other. Because of this, there is a growing need to assess the integrated impact of SLR taking into account the interactions between physical and ecological factors to make more informed decisions for the design of adaptation strategies. This study presents a methodology for improved SLR-induced flood-damage assessments in natural areas which is composed of (i) a pseudo-dynamic method coupling equilibrium-based coastal response and classical bathtub modeling approaches and (ii) a simple method to account for habitat conversion following inundation. This methodology is applied to low-lying coastal areas of Catalonia under different SLR scenarios, which show very different sensitivities depending on the configuration of the water-land border, topography, geomorphology, and degree of human impact on the floodplain. In terms of potential impact, natural habitats will be the most benefited from the likely conversion at the expense of agriculture lands. This can help coastal managers to adopt adaptation strategies where considering the inherent capacity of some coastal landscapes to adapt opens up new alternatives. Full article

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

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18 pages, 3884 KiB

Open AccessEditor’s ChoiceArticle

Water Use Conflict and Coordination between Agricultural and Wetlands—A Case Study of Yanqi Basin

by Mengyao Jiang, Shuntao Xie and Shuixian Wang

Water 2020, 12(11), 3225; https://doi.org/10.3390/w12113225 - 18 Nov 2020

Cited by 6 | Viewed by 3316

Abstract

Increased groundwater extraction leads to the decrease of the extent of wetlands due to the implementation of a water-saving transformation project in an arid irrigation area. The application of integrated mitigation tools and strategies in China have increasing significance. In this study, an [...] Read more.

Increased groundwater extraction leads to the decrease of the extent of wetlands due to the implementation of a water-saving transformation project in an arid irrigation area. The application of integrated mitigation tools and strategies in China have increasing significance. In this study, an integrated approach (SWAT-MODFLOW) was followed; it is based on a soil and water assessment tool (SWAT) coupled with a modular three-dimensional finite difference groundwater model (MODFLOW). Recharge and evaporation values were estimated by SWAT and were then used to simulate groundwater in a MODFLOW model. Calibration (over the years 2000–2010) and validation (over the years 2010–2016) were performed, based on observed groundwater-level data; results showed that the combined SWAT-MODFLOW provides more accurate simulation and prediction of the dynamic changes of surface water and groundwater in irrigation areas than results from individual MODFLOW models. This method was applied to the Yanqi Basin, which is one of the most appropriate arid agricultural basins for modeling lake wetland and groundwater in China. The correlation coefficients (R²) between the simulated and real groundwater level are 0.96 and 0.91 in SWAT-MODFLOW and MODFLOW, respectively. With the gradual increase in the extraction to 248%, 0.62 × 10⁸ m³ of groundwater discharged into the lake became −2.25 × 10⁸ m³. The lake level drops 1.3 m compared with the current year, when the groundwater exploitation increases by 10 × 10⁸ m³/year. Overall, the results of the coupling model offer scientific evidence for agricultural water management and lake recovery, so as to enhance the water use coordination. Full article

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

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16 pages, 7191 KiB

Open AccessEditor’s ChoiceArticle

A New Approach to Calculate the Water Exploitation Index (WEI⁺)

by Stefano Casadei, Francesco Peppoloni and Arnaldo Pierleoni

Water 2020, 12(11), 3227; https://doi.org/10.3390/w12113227 - 18 Nov 2020

Cited by 15 | Viewed by 10763

Abstract

The Water Exploitation Index (WEI), or withdrawal ratio, is an indicator of water scarcity, which has been updated into its WEI⁺ form by the Committee of Experts of the European Commission. In calculating the total abstraction of fresh water, this indicator also [...] Read more.

The Water Exploitation Index (WEI), or withdrawal ratio, is an indicator of water scarcity, which has been updated into its WEI⁺ form by the Committee of Experts of the European Commission. In calculating the total abstraction of fresh water, this indicator also includes the possible return flow and management rules. The demand for freshwater and long-term freshwater resources are both necessary to calculate the WEI⁺. These values are not easy to assess at basin or sub-basin level and, for this reason, WEI values are generally calculated at the country level. This paper introduces a new approach to calculate the WEI⁺, with the purpose of extending its use to basin and sub-basin levels. The methodology is based on flow duration curve estimation, which evaluates freshwater resources, and a Web-GIS system that evaluates water abstractions distribution. This approach allows for the assessment of locally stressed areas in the hydrographic network and could provide a fundamental step toward more comprehensive regional water resources management plans. The new methodology is tested in some sub-basins of the Upper Tiber River Basin (Italy). These results contribute to the analysis of water withdrawals sustainability, based on the policy of the European Environment Agency, which is aimed toward the development of a proactive approach for reducing water stress. Full article

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21 pages, 14545 KiB

Open AccessEditor’s ChoiceArticle

Structural Diversity in Early-Stage Biofilm Formation on Microplastics Depends on Environmental Medium and Polymer Properties

by Anja F. R. M. Ramsperger, Anja C. Stellwag, Anja Caspari, Andreas Fery, Tillmann Lueders, Holger Kress, Martin G. J. Löder and Christian Laforsch

Water 2020, 12(11), 3216; https://doi.org/10.3390/w12113216 - 17 Nov 2020

Cited by 42 | Viewed by 7719

Abstract

Plastics entering the environment can not only undergo physical degradation and fragmentation processes, but they also tend to be colonized by microorganisms. Microbial colonization and the subsequent biofilm formation on plastics can alter their palatability to organisms and result in a higher ingestion [...] Read more.

Plastics entering the environment can not only undergo physical degradation and fragmentation processes, but they also tend to be colonized by microorganisms. Microbial colonization and the subsequent biofilm formation on plastics can alter their palatability to organisms and result in a higher ingestion as compared to pristine plastics. To date, the early stage of biofilm formation on plastic materials has not been investigated in context of the environmental medium and polymer properties. We explored the early-stage biofilm formation on polyamide (PA), polyethylene terephthalate (PET), and polyvinyl chloride (PVC) after incubation in freshwater and artificial seawater and categorized the structural diversity on images obtained via scanning electron microscopy. Furthermore, by the measurement of the initial ζ-potential of the plastic materials, we found that PA with the highest negative ζ-potential tended to have the highest structural diversity, followed by PET and PVC after incubation in freshwater. However, PVC with the lowest negative ζ-potential showed the highest structural diversity after incubation in seawater, indicating that the structural diversity is additionally dependent on the incubation medium. Our results give insights into how the incubation medium and polymer properties can influence the early-stage biofilm formation of just recently environmentally exposed microplastics. These differences are responsible for whether organisms may ingest microplastic particles with their food or not. Full article

(This article belongs to the Special Issue Microplastics in Aquatic Environments and Wastewater Treatment )

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27 pages, 7366 KiB

Open AccessEditor’s ChoiceArticle

Machine Learning to Estimate Surface Soil Moisture from Remote Sensing Data

by Hamed Adab, Renato Morbidelli, Carla Saltalippi, Mahmoud Moradian and Gholam Abbas Fallah Ghalhari

Water 2020, 12(11), 3223; https://doi.org/10.3390/w12113223 - 17 Nov 2020

Cited by 123 | Viewed by 12901

Abstract

Soil moisture is an integral quantity parameter in hydrology and agriculture practices. Satellite remote sensing has been widely applied to estimate surface soil moisture. However, it is still a challenge to retrieve surface soil moisture content (SMC) data in the heterogeneous catchment at [...] Read more.

Soil moisture is an integral quantity parameter in hydrology and agriculture practices. Satellite remote sensing has been widely applied to estimate surface soil moisture. However, it is still a challenge to retrieve surface soil moisture content (SMC) data in the heterogeneous catchment at high spatial resolution. Therefore, it is necessary to improve the retrieval of SMC from remote sensing data, which is important in the planning and efficient use of land resources. Many methods based on satellite-derived vegetation indices have already been developed to estimate SMC in various climatic and geographic conditions. Soil moisture retrievals were performed using statistical and machine learning methods as well as physical modeling techniques. In this study, an important experiment of soil moisture retrieval for investigating the capability of the machine learning methods was conducted in the early spring season in a semi-arid region of Iran. We applied random forest (RF), support vector machine (SVM), artificial neural network (ANN), and elastic net regression (EN) algorithms to soil moisture retrieval by optical and thermal sensors of Landsat 8 and knowledge of land-use types on previously untested conditions in a semi-arid region of Iran. The statistical comparisons show that RF method provided the highest Nash–Sutcliffe efficiency value (0.73) for soil moisture retrieval covered by the different land-use types. Combinations of surface reflectance and auxiliary geospatial data can provide more valuable information for SMC estimation, which shows promise for precision agriculture applications. Full article

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

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16 pages, 711 KiB

Open AccessEditor’s ChoiceReview

Perspectives on Micro(Nano)Plastics in the Marine Environment: Biological and Societal Considerations

by Joana Soares, Isabel Miguel, Cátia Venâncio, Isabel Lopes and Miguel Oliveira

Water 2020, 12(11), 3208; https://doi.org/10.3390/w12113208 - 16 Nov 2020

Cited by 35 | Viewed by 6101

Abstract

Marine litter is a global problem which has been negatively affecting the environment. Plastic materials are the most commonly found marine debris, with potential biological (not only for aquatic organisms but also for humans) as well as socio-economic impacts. Considering that it is [...] Read more.

Marine litter is a global problem which has been negatively affecting the environment. Plastic materials are the most commonly found marine debris, with potential biological (not only for aquatic organisms but also for humans) as well as socio-economic impacts. Considering that it is an anthropogenic problem, society could play an important role to minimize it. Although a considerable amount of research has addressed the biological effects of plastics (micro(nano)plastics) on biota, few studies have addressed how scientific information is being transmitted to the public and the potential role of citizen environmental education. The current paper discusses known effects, researched topics and how scientific knowledge is currently being transmitted to the public. Full article

(This article belongs to the Special Issue Microplastics in Aquatic Environments and Wastewater Treatment )

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21 pages, 6720 KiB

Open AccessEditor’s ChoiceArticle

Assessing the Effectiveness of Sustainable Drainage Systems (SuDS): Interventions, Impacts and Challenges

by Sarah Cotterill and Louise J. Bracken

Water 2020, 12(11), 3160; https://doi.org/10.3390/w12113160 - 12 Nov 2020

Cited by 29 | Viewed by 26739

Abstract

Sustainable drainage systems (SuDS) can be a key tool in the management of extremes of rainfall, due to their capacity to attenuate and treat surface water. Yet, implementation is a complex process, requiring buy-in from multiple stakeholders. Buy-in is often undermined by a [...] Read more.

Sustainable drainage systems (SuDS) can be a key tool in the management of extremes of rainfall, due to their capacity to attenuate and treat surface water. Yet, implementation is a complex process, requiring buy-in from multiple stakeholders. Buy-in is often undermined by a lack of practical evidence and monitoring of implemented SuDS. In this paper, we present a collaborative case study between a local authority, university and the UK Environment Agency. This partnership approach enabled the installation of SuDS and monitoring equipment to address surface runoff in the north east of England. Ultrasonic sensors were installed in the drainage network to evaluate the attenuation of surface water. SuDS were installed during an atypically wet spring, followed by a hot and dry summer, providing a range of conditions to assess their performance. Results demonstrate that there was a statistically significant difference in the detected flow level in manholes downstream of the SuDS interventions. Several challenges occurred, from signal obstacles in wireless telecommunication services, to logistical constraints of installing sensors in the drainage network, and issues with the adoption of property level SuDS. These issues require further research. Qualitative support for partnership working was crucial to increase the capacity for delivering SuDS. To ensure the success of future schemes and likelihood of SuDS uptake, partnership working and engaging with communities is vital. Full article

(This article belongs to the Special Issue Innovative, Smart and Sustainable Solutions for Urban Stormwater Management)

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