Water

22 pages, 2478 KiB

Open AccessArticle

Seasonal Dynamics of Algal Net Primary Production in Response to Phosphorus Input in a Mesotrophic Subtropical Plateau Lake, Southwestern China

by Yue Wu, Jinpeng Zhang, Zeying Hou, Zebin Tian, Zhaosheng Chu and Shengrui Wang

Water 2022, 14(5), 835; https://doi.org/10.3390/w14050835 - 07 Mar 2022

Cited by 5 | Viewed by 2763

Abstract

A comprehensive 3-dimensional hydrodynamic and eutrophication model, the environmental fluid dynamics code model (EFDC) with three functional phytoplankton groups, was applied to simulate the algal dynamics in a mesotrophic P-limited subtropical plateau lake, Lake Erhai, Southwestern China. Field investigations revealed the seasonal patterns [...] Read more.

A comprehensive 3-dimensional hydrodynamic and eutrophication model, the environmental fluid dynamics code model (EFDC) with three functional phytoplankton groups, was applied to simulate the algal dynamics in a mesotrophic P-limited subtropical plateau lake, Lake Erhai, Southwestern China. Field investigations revealed the seasonal patterns in external total phosphorus (TP) input and TP concentration, as well as the composition of the phytoplankton community. The model was calibrated to reproduce qualitative features and the succession of phytoplankton communities, and the net primary production was calculated. The modeled daily net primary production (NPP) ranged between −16.89 and 15.12 mg C/m²/d and exhibited significant seasonal variation. The competition for phosphorus and temperature was identified as the primary governing factor of NPP by analyzing the parameter sensitivity and limitation factors of the lake. The simulation of four nutrient loading reduction scenarios suggested high phytoplankton biomass and NPP sensitivity to the external TP reduction. A significant positive correlation was found among NPP, total phytoplankton biomass and TP concentration. Overall, this work offers an alternative approach to estimating lake NPP, which has the potential to improve sustainable lake management. Full article

(This article belongs to the Special Issue Non-point Source Pollution across Headwater Catchments to Large River Networks)

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22 pages, 3272 KiB

Open AccessArticle

Differential Response of Nutrients to Seasonal Hydrological Changes and a Rain Event in a Subtropical Watershed, Southeast China

by Xiaolan Guo, Xiuli Yan, Hongyan Bao, Junwen Wu and Shuhji Kao

Water 2022, 14(5), 834; https://doi.org/10.3390/w14050834 - 07 Mar 2022

Cited by 1 | Viewed by 2403

Abstract

A large amount of terrestrial nutrients are discharged into the ocean through rivers. However, the impact of seasonal hydrological variations on riverine nutrient concentrations and fluxes remains unclear, especially in the medium-sized subtropical rivers that are highly influenced by human activities. In this [...] Read more.

A large amount of terrestrial nutrients are discharged into the ocean through rivers. However, the impact of seasonal hydrological variations on riverine nutrient concentrations and fluxes remains unclear, especially in the medium-sized subtropical rivers that are highly influenced by human activities. In this study, we investigated the monthly changes in nutrient concentrations (soluble reactive phosphorus, SRP; dissolved silicate, DSi; and dissolved inorganic nitrogen, DIN) in the North Stream (NS) and West Stream (WS) of the Jiulong River (JLR). The results show that the concentrations of SRP and DSi in the NS and the WS displayed a similar seasonal variability, which was different from the pattern of DIN. Hydrological conditions, chemical fertilizer loss and biogeochemical processes are responsible for the seasonal changes in the nutrients in the two streams, especially during extreme rain events. Nutrient concentrations in the NS exhibited a clockwise trajectory along with river discharge during rain events, while a reverse pattern in the WS was observed since it experienced a moderately long rain event. Different rainfall features between the two main tributaries resulted in the majority of nutrients being exported at the start of the rain event in the NS and the end of rain event in the WS. Indeed, the annual high flow (Q/Q_m > 3) accounts for ~17.3% of the annual nutrient flux in the JLR even though this period spans only ~4.0% of a year, which suggests the importance of rain events on nutrient export in these subtropical rivers. Although the annual fluxes of DIN and SRP in the JLR were smaller than many rivers worldwide, higher areal yields of DIN and SRP were observed, indicating that the JLR is highly influenced by human activities. Our study systematically evaluated the response of nutrient concentrations to hydrological changes in two tributaries of the JLR, which is useful in better understanding the nutrient dynamics in medium-sized subtropical rivers. Full article

(This article belongs to the Special Issue Non-point Source Pollution across Headwater Catchments to Large River Networks)

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12 pages, 618 KiB

Open AccessArticle

Evaluation of Pre-Analytical and Analytical Methods for Detecting SARS-CoV-2 in Municipal Wastewater Samples in Northern Italy

by Laura Pellegrinelli, Sara Castiglioni, Clementina E. Cocuzza, Barbara Bertasi, Valeria Primache, Silvia Schiarea, Giulia Salmoiraghi, Andrea Franzetti, Rosario Musumeci, Michela Tilola, Elisa Galuppini, Giorgio Bertanza, Marialuisa Callegari, Fabrizio Stefani, Andrea Turolla, Emanuela Ammoni, Danilo Cereda, Elena Pariani, Sandro Binda and the WBE Study Group

Water 2022, 14(5), 833; https://doi.org/10.3390/w14050833 - 07 Mar 2022

Cited by 9 | Viewed by 2486

Abstract

(1) Background: The surveillance of SARS-CoV-2 RNA in urban wastewaters allows one to monitor the presence of the virus in a population, including asymptomatic and symptomatic individuals, capturing the real circulation of this pathogen. The aim of this study was to evaluate the [...] Read more.

(1) Background: The surveillance of SARS-CoV-2 RNA in urban wastewaters allows one to monitor the presence of the virus in a population, including asymptomatic and symptomatic individuals, capturing the real circulation of this pathogen. The aim of this study was to evaluate the performance of different pre-analytical and analytical methods for identifying the presence of SARS-CoV-2 in untreated municipal wastewaters samples by conducting an inter-laboratory proficiency test. (2) Methods: three methods of concentration, namely, (A) Dextran and PEG-6000 two-phase separation, (B) PEG-8000 precipitation without a chloroform purification step and (C) PEG-8000 precipitation with a chloroform purification step were combined with three different protocols of RNA extraction by using commercial kits and were tested by using two primers/probe sets in three different master mixes. (3) Results: PEG-8000 precipitation without chloroform treatment showed the best performance in the SARS-CoV-2 recovery; no major differences were observed among the protocol of RNA extraction and the one-step real-time RT-PCR master mix kits. The highest analytic sensitivity was observed by using primers/probe sets targeting the N1/N3 fragments of SARS-CoV-2. (4) Conclusions: PEG-8000 precipitation in combination with real-time RT-PCR targeting the N gene (two fragments) was the best performing workflow for the detection of SARS-CoV-2 RNA in municipal wastewaters. Full article

(This article belongs to the Special Issue Pathogen Detection and Identification in Wastewater)

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12 pages, 1821 KiB

Open AccessArticle

Comparison of the Seismic Responses of an Arch Dam under Excitation from the Design Response Spectrum in the New and Old Chinese National Standards

by Binghan Xue, Jing Wang, Na Li, Chao Zhang and Jianguo Chen

Water 2022, 14(5), 832; https://doi.org/10.3390/w14050832 - 07 Mar 2022

Cited by 1 | Viewed by 1665

Abstract

The new Chinese national standard, Standard for the seismic design of hydraulic structures (GB51247-2018), has been published. Compared with the Specifications for the seismic design of hydraulic structures (SL203-1997), the standard design response spectrum curve was revised in the new national standard. In [...] Read more.

The new Chinese national standard, Standard for the seismic design of hydraulic structures (GB51247-2018), has been published. Compared with the Specifications for the seismic design of hydraulic structures (SL203-1997), the standard design response spectrum curve was revised in the new national standard. In order to compare the seismic responses of an arch dam under excitation from the design response spectrum in the new and old standards, the dynamic calculation of a 240 m high arch dam is carried out by a three-dimensional finite element method. In the dynamic calculation, the B-differentiable equation is used to simulate the tension motion of arch dam contraction joints, and the multi-transmitting boundary method and the Westergaard added mass method are used to simulate the dam–infinite foundation and dam–reservoir interactions, respectively. The results show that the dynamic stress responses of the arch dam under excitation from the design response spectrum in the new standard are increased compared with those of the old standard. The seismic safety of an arch dam may decrease under excitation from the design response spectrum in the new standard. Thus, the seismic validation on built arch dams should be carried out by using the new standard when it is possible. Full article

(This article belongs to the Special Issue Safety Evaluation of Dam and Geotechnical Engineering)

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18 pages, 7541 KiB

Open AccessFeature PaperArticle

In Situ Experimental Study of Natural Diatomaceous Earth Slopes under Alternating Dry and Wet Conditions

by Zhixing Deng, Wubin Wang, Tengfei Yan, Kang Xie, Yandong Li, Yangyang Liu and Qian Su

Water 2022, 14(5), 831; https://doi.org/10.3390/w14050831 - 07 Mar 2022

Cited by 3 | Viewed by 3000

Abstract

Very few studies have focused on diatomaceous earth slopes along high-speed railways, and the special properties of diatomaceous earth under alternating dry and wet conditions are unknown. This paper studies diatomaceous earth in the Shengzhou area, through which the newly built Hangzhou–Taizhou high-speed [...] Read more.

Very few studies have focused on diatomaceous earth slopes along high-speed railways, and the special properties of diatomaceous earth under alternating dry and wet conditions are unknown. This paper studies diatomaceous earth in the Shengzhou area, through which the newly built Hangzhou–Taizhou high-speed railway passes, and the basic physical and hydraulic properties of diatomaceous earth are analyzed by indoor test methods. A convenient, efficient, and controllable high-speed railway slope artificial rainfall simulation system is designed, and in situ comprehensive monitoring and fissure observation are performed on site to analyze the changes in various diatomaceous soil slope parameters under rainfall infiltration, and to explore the cracking mechanisms of diatomaceous earth under alternating dry and wet conditions. The results indicate extremely poor hydrophysical properties of diatomaceous earth in the Shengzhou area; the disintegration resistance index values of natural diatomaceous earth samples subjected to dry and wet cycles are 1.8–5.6%, and the disintegration is strong. Comprehensive indoor tests and water content monitoring show that natural diatomaceous earth has no obvious influence when it contacts water, but it disintegrates and cracks under alternating dry and wet conditions. The horizontal displacement of both slope types mainly occurs within 0.75–2.75 m of the surface layer, indicating shallow surface sliding; after testing, natural slope crack widths of diatomaceous earth reach 10–25 mm, and their depths reach 40–60 cm. To guarantee safety during high-speed railway engineering construction, implementing proper protection for diatomaceous earth slopes is recommended. Full article

(This article belongs to the Topic Natural Hazards and Disaster Risks Reduction)

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14 pages, 4299 KiB

Open AccessArticle

Karst Lake’s Dynamics Analysis as a Tool for Aquifer Characterisation at Field Scale, Example of Cryptodepression—Red Lake in Croatia

by Adrijana Vrsalović, Ivo Andrić, Nenad Buzjak and Ognjen Bonacci

Water 2022, 14(5), 830; https://doi.org/10.3390/w14050830 - 07 Mar 2022

Cited by 3 | Viewed by 2172

Abstract

This paper analyses complex hydrological and hydrogeological properties of a deep karstic lake and its surroundings. Red Lake (Croatia) is a cryptodepression in the karst massif rich in well-developed extreme surface karst forms and underground conduit system. It is interconnected with other close [...] Read more.

This paper analyses complex hydrological and hydrogeological properties of a deep karstic lake and its surroundings. Red Lake (Croatia) is a cryptodepression in the karst massif rich in well-developed extreme surface karst forms and underground conduit system. It is interconnected with other close water bodies and offers information on groundwater movement and characteristics. The article analyses hourly data on precipitation and water levels in Red Lake and compares them with data on discharges from near Opačac Spring for a period of five years. Data gaps in the record caused by operational interruptions of the measuring equipment were compensated by the use of neural networks. The study of the hydrodynamics of karst surroundings under recession was conducted by observing the receding water levels and corresponding lake’s volumetry. By isolating recession periods from the record of integral water volume change, some of the common techniques in recession analysis were performed aiming to acquire new knowledge on the hydrogeological regime of the karst system at the field scale. Additionally, spectral analysis was used as another tool of karst system characterisation since it enables the signal decomposition in the frequency domain and detection of dominant flow processes. Full article

(This article belongs to the Section Hydrogeology)

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30 pages, 3636 KiB

Open AccessFeature PaperArticle

Land Use Change to Reduce Freshwater Nitrogen and Phosphorus will Be Effective Even with Projected Climate Change

by Andrew J. Wade, Richard A. Skeffington, Raoul-Marie Couture, Martin Erlandsson Lampa, Simon Groot, Sarah J. Halliday, Valesca Harezlak, Josef Hejzlar, Leah A. Jackson-Blake, Ahti Lepistö, Eva Papastergiadou, Joan Lluís Riera, Katri Rankinen, Maria Shahgedanova, Dennis Trolle, Paul G. Whitehead, Demetris Psaltopoulos and Dimitris Skuras

Water 2022, 14(5), 829; https://doi.org/10.3390/w14050829 - 06 Mar 2022

Cited by 6 | Viewed by 3868

Abstract

Recent studies have demonstrated that projected climate change will likely enhance nitrogen (N) and phosphorus (P) loss from farms and farmland, with the potential to worsen freshwater eutrophication. Here, we investigate the relative importance of the climate and land use drivers of nutrient [...] Read more.

Recent studies have demonstrated that projected climate change will likely enhance nitrogen (N) and phosphorus (P) loss from farms and farmland, with the potential to worsen freshwater eutrophication. Here, we investigate the relative importance of the climate and land use drivers of nutrient loss in nine study catchments in Europe and a neighboring country (Turkey), ranging in area from 50 to 12,000 km². The aim was to quantify whether planned large-scale, land use change aimed at N and P loss reduction would be effective given projected climate change. To this end, catchment-scale biophysical models were applied within a common framework to quantify the integrated effects of projected changes in climate, land use (including wastewater inputs), N deposition, and water use on river and lake water quantity and quality for the mid-21st century. The proposed land use changes were derived from catchment stakeholder workshops, and the assessment quantified changes in mean annual N and P concentrations and loads. At most of the sites, the projected effects of climate change alone on nutrient concentrations and loads were small, whilst land use changes had a larger effect and were of sufficient magnitude that, overall, a move to more environmentally focused farming achieved a reduction in N and P concentrations and loads despite projected climate change. However, at Beyşehir lake in Turkey, increased temperatures and lower precipitation reduced water flows considerably, making climate change, rather than more intensive nutrient usage, the greatest threat to the freshwater ecosystem. Individual site responses did however vary and were dependent on the balance of diffuse and point source inputs. Simulated lake chlorophyll-a changes were not generally proportional to changes in nutrient loading. Further work is required to accurately simulate the flow and water quality extremes and determine how reductions in freshwater N and P translate into an aquatic ecosystem response. Full article

(This article belongs to the Special Issue Ecological Monitoring and Assessment of Freshwater Ecosystems: New Trends and Future Challenges)

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17 pages, 3723 KiB

Open AccessArticle

Study on the Processes Influencing and Importance of Ecological Water Replenishment for Groundwater Resources: A Case Study in Yongding River

by Congchao Xu, Ying Sun, Bowen Shi, Xinjuan Wang, Rui Li, Mingxiao Li, Beidou Xi and Chuanping Feng

Water 2022, 14(5), 828; https://doi.org/10.3390/w14050828 - 06 Mar 2022

Cited by 2 | Viewed by 2336

Abstract

There has been notable depletion of groundwater resources globally in recent decades. Groundwater can be conserved by ecological water replenishment. An understanding of the factors influencing the effect of ecological water replenishment on groundwater recharge is of great significance for water resource management. [...] Read more.

There has been notable depletion of groundwater resources globally in recent decades. Groundwater can be conserved by ecological water replenishment. An understanding of the factors influencing the effect of ecological water replenishment on groundwater recharge is of great significance for water resource management. This study used the improved water table fluctuation and water equilibrium method and Spearman correlation analysis in R to evaluate the effect of ecological water replenishment on groundwater recharge. Furthermore, the correlations between groundwater recharge and topography, hydrogeological conditions, and meteorological factors were analyzed. Groundwater storage in the plain area of the Yongding River (Beijing section) increased by 2.17 × 10⁸ m³ in 2020, equating to an increase in the regional groundwater level of 73.6% (increase of 0.1–9.1 m, arithmetic mean of 2.3 m). The main sources of groundwater recharge are ecological water replenishment and precipitation. The ecological water replenishment first recharged the Ordovician limestone aquifer in the gorge area, following which karst water overflowed through the fault zone to resupply the Quaternary groundwater in the plain area, resulting in a lag in the groundwater recharge effect. Groundwater recharge was positively correlated with ground elevation and aquifer permeability and negatively correlated with the thickness of Quaternary strata and the distance between the recharge point and Yongdinghe fault zone. This study can help to better explain the effect and impact of ecological water replenishment on groundwater resource recharge and its implications for improving ecological water replenishment projects. Full article

(This article belongs to the Section Hydrogeology)

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23 pages, 2256 KiB

Open AccessArticle

Development of Quantitative Real-Time PCR for Detecting Environmental DNA Derived from Marine Macrophytes and Its Application to a Field Survey in Hiroshima Bay, Japan

by Masami Hamaguchi, Toshihiro Miyajima, Hiromori Shimabukuro and Masakazu Hori

Water 2022, 14(5), 827; https://doi.org/10.3390/w14050827 - 06 Mar 2022

Cited by 8 | Viewed by 4197

Abstract

The sequestration and storage of carbon dioxide by marine macrophytes is called blue carbon; this ecosystem function of coastal marine ecosystems constitutes an important countermeasure to global climate change. The contribution of marine macrophytes to blue carbon requires a detailed examination of the [...] Read more.

The sequestration and storage of carbon dioxide by marine macrophytes is called blue carbon; this ecosystem function of coastal marine ecosystems constitutes an important countermeasure to global climate change. The contribution of marine macrophytes to blue carbon requires a detailed examination of the organic carbon stock released by these macrophytes. Here, we introduce a quantitative real-time polymerase chain reaction (qPCR)-based environmental DNA (eDNA) system for the species-specific detection of marine macrophytes. and report its application in a field survey in Hiroshima Bay, Japan. A method of qPCR-based quantification was developed for mangrove, seagrass, Phaeophyceae, Rhodophyta and Chlorophyta species, or species-complex, collected from the Japanese coast to investigate their dynamics after they wither and die in the marine environment. A trial of the designed qPCR system was conducted using sediment samples from Hiroshima Bay. Ulva spp. were abundant in coastal areas of the bay, yet their eDNA in the sediments was scarce. In contrast, Zostera marina and the Sargassum subgenus Bactrophycus spp. were found at various sites in the bay, and high amounts of their eDNA were detected in the sediments. These results suggest that the fate of macrophyte-derived organic carbon after death varies among species. Full article

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

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20 pages, 2095 KiB

Open AccessArticle

Role of Water Policies in the Adoption of Smart Water Metering and the Future Market

by Spancer Msamadya, Jin Chul Joo, Jung Min Lee, Jong Soo Choi, Sangho Lee, Doo Jin Lee, Hyeon Woo Go, So Ye Jang and Dong Hwi Lee

Water 2022, 14(5), 826; https://doi.org/10.3390/w14050826 - 06 Mar 2022

Cited by 9 | Viewed by 4041

Abstract

Both status and progress in smart water metering (SWM) implementations in five selected countries (i.e., United States of America, United Kingdom, Australia, Israel, and South Korea) are investigated in this study. Despite the countless benefits of SWM implementation, the diffusion of the SWM [...] Read more.

Both status and progress in smart water metering (SWM) implementations in five selected countries (i.e., United States of America, United Kingdom, Australia, Israel, and South Korea) are investigated in this study. Despite the countless benefits of SWM implementation, the diffusion of the SWM technologies has been slow due to various challenges, including the absence of compulsory water policies, the lack of support from customers and expertise, and weak cost–benefit analysis. Over the past 30 years, the aforementioned countries have transitioned from a fixed charging to a volumetric charging regime composed of traditional water meters and SWM. Both the status and progress of SWM implementation are quite different among countries, although governments across the world have been applying water policies responding to water scarcity, population growth, and water demand management. However, the absence of strong water policies and political support for SWM implementation resulted in the slow and retarded spread of SWM implementation. Although several changes in water policies have occurred since 1990, there is no compulsory law for SWM implementation. Between 1995 and 2010, pilot/trial cases for SWM were dominant. After 2010, the number of SWM implementation kept increasing and all countries experienced more concentrated SWM implementation, despite the variances in both endpoints and completion of SWM implementation depending on water policies (i.e., acts and regulations) encouraging SWM implementations. The global market for SWM has consistently grown to USD 5.92 billion in 2020. Finally, the application of favourable water policies to optimize the use of water resources and to promote sustainable development is expected to drive the SWM market further. Full article

(This article belongs to the Special Issue Advance in Water Management and Water Policy Research)

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34 pages, 1482 KiB

Open AccessFeature PaperReview

An Overview of Polymer-Supported Catalysts for Wastewater Treatment through Light-Driven Processes

by Maria João Silva, João Gomes, Paula Ferreira and Rui C. Martins

Water 2022, 14(5), 825; https://doi.org/10.3390/w14050825 - 06 Mar 2022

Cited by 11 | Viewed by 2353

Abstract

In recent years, alarm has been raised due to the presence of chemical contaminants of emerging concern (CECs) in water. This concern is due to the risks associated with their exposure, even in small amounts. These complex compounds cannot be removed or degraded [...] Read more.

In recent years, alarm has been raised due to the presence of chemical contaminants of emerging concern (CECs) in water. This concern is due to the risks associated with their exposure, even in small amounts. These complex compounds cannot be removed or degraded by existing technologies in wastewater treatment plants. Therefore, advanced oxidation processes have been studied, with the objective of developing a technology capable of complementing the conventional water treatment plants. Heterogenous photocatalysis stands out for being a cost-effective and environmentally friendly process. However, its most common form (with suspended catalytic particles) requires time-consuming and costly downstream processes. Therefore, the heterogeneous photocatalysis process with a supported catalyst is preferable. Among the available supports, polymeric ones stand out due to their favorable characteristics, such as their transparency, flexibility and stability. This is a relatively novel process; therefore, there are still some gaps in the scientific knowledge. Thus, this review article aims to gather the existing information about this process and verify which questions are still to be answered. Full article

(This article belongs to the Special Issue Effects of Advanced Oxidation Treatment Processes on the Ecotoxicity of Wastewater)

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17 pages, 1773 KiB

Open AccessArticle

Forecasting Guangdong’s Marine Science and Technology, Marine Economy, and Employed Persons by Coastal Regions—Based on Rolling Grey MGM(1,m) Model

by Xin Shan and Yun Cao

Water 2022, 14(5), 824; https://doi.org/10.3390/w14050824 - 06 Mar 2022

Cited by 5 | Viewed by 1918

Abstract

The development of marine scientific and technological innovation is an important force for realizing the high-quality development of the marine economy. The purpose of this paper is to predict the development trend of marine science and technology development, marine economy, and employed persons [...] Read more.

The development of marine scientific and technological innovation is an important force for realizing the high-quality development of the marine economy. The purpose of this paper is to predict the development trend of marine science and technology development, marine economy, and employed persons by coastal regions in Guangdong Province, and to give policy suggestions for the future direction of the development of marine technology in Guangdong. Considering the new information priority principle, this paper uses the data from 2011 to 2016 to predict the development trend of marine science and technology, marine economy, and employed persons by coastal regions in Guangdong Province from 2017 to 2022 with the rolling RMGM(1,m) model. It is found that the level of marine science and technology and marine economy in Guangdong maintains stable growth, but marine science and technology capabilities still need to be strengthened. On the one hand, the research reveals the development trend of Guangdong’s marine science and technology innovation and marine economy, and it provides a direction for the high-quality development of Guangdong’s marine economy. On the other hand, the research confirms the validity of the MGM(1,m) model and enriches the research field of grey forecasting models. Full article

(This article belongs to the Special Issue Marine Economic Development and Conservation)

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21 pages, 4831 KiB

Open AccessFeature PaperArticle

Vulnerability and Risk Assessment to Climate Change in Sagar Island, India

by Aparna Bera, Gowhar Meraj, Shruti Kanga, Majid Farooq, Suraj Kumar Singh, Netrananda Sahu and Pankaj Kumar

Water 2022, 14(5), 823; https://doi.org/10.3390/w14050823 - 06 Mar 2022

Cited by 34 | Viewed by 6496

Abstract

Inhabitants of low-lying islands face increased threats due to climate change as a result of their higher exposure and lesser adaptive capacity. Sagar Island, the largest inhabited estuarine island of Sundarbans, is experiencing severe coastal erosion, frequent cyclones, flooding, storm surges, and breaching [...] Read more.

Inhabitants of low-lying islands face increased threats due to climate change as a result of their higher exposure and lesser adaptive capacity. Sagar Island, the largest inhabited estuarine island of Sundarbans, is experiencing severe coastal erosion, frequent cyclones, flooding, storm surges, and breaching of embankments, resulting in land, livelihood, and property loss, and the displacement of people at a huge scale. The present study assessed climate change-induced vulnerability and risk for Sagar Island, India, using an integrated geostatistical and geoinformatics-based approach. Based on the IPCC AR5 framework, the proportion of variance of 26 exposure, hazard, sensitivity, and adaptive capacity parameters was measured and analyzed. The results showed that 19.5% of mouzas (administrative units of the island), with 15.33% of the population at the southern part of the island, i.e., Sibpur–Dhablat, Bankimnagar–Sumatinagar, and Beguakhali–Mahismari, are at high risk (0.70–0.80). It has been concluded that the island has undergone tremendous land system transformations and changes in climatic patterns. Therefore, there is a need to formulate comprehensive adaptation strategies at the policy- and decision-making levels to help the communities of this island deal with the adverse impacts of climate change. The findings of this study will help adaptation strategies based on site-specific information and sustainable management for the marginalized populations living in similar islands worldwide. Full article

(This article belongs to the Special Issue Water Resource Management through the Lens of Planetary Health Approach)

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18 pages, 2403 KiB

Open AccessArticle

Role of Ecohydrographical Barriers on the Spatio-Temporal Distribution of Chaetognath Community in the Gulf of Aqaba during Summer

by Kusum Komal Karati, Gopinath Vineetha, Reny P. Devassy, Ali M. Al-Aidaroos and Mohsen M. El-Sherbiny

Water 2022, 14(5), 822; https://doi.org/10.3390/w14050822 - 06 Mar 2022

Cited by 1 | Viewed by 1867

Abstract

The Gulf of Aqaba (GoA), positioned between the Sinai Peninsula and the Saudi Arabian coast is characterized by its uniquely high saline, oligotrophic waters, and seasonally stratified hydrography. Despite its geographical significance, information on its zooplankton ecology and biodiversity is still meager. Hence, [...] Read more.

The Gulf of Aqaba (GoA), positioned between the Sinai Peninsula and the Saudi Arabian coast is characterized by its uniquely high saline, oligotrophic waters, and seasonally stratified hydrography. Despite its geographical significance, information on its zooplankton ecology and biodiversity is still meager. Hence, the present study was aimed to investigate the detailed diversity and ecology of the dominant carnivorous zooplankton taxon chaetognath in the pelagic waters of the GoA during summer. Despite the known water flow exchange between the GoA and the Red Sea, only five chaetognath species were observed in GoA which is markedly less than the number earlier recorded in the Red Sea, indicating the role of high saline water mass as an ecophysiological boundary for the inhabitance of many epipelagic chaetognaths. Euryhaline, Serratosagitta pacifica formed the dominant species in both the surface water and the upper 200 m water column and was observed to be the most suitable representative of this high saline environment. Conspicuous diel variability in the distribution of the different growth stages of chaetognaths in the surface waters can be attributed to their varied susceptibility to visually oriented predators. The positive relation observed in the abundance of chaetognaths and their main prey, copepods, and their carbon and nitrogen contents indicated their significance in the pelagic trophic ecology of the GoA. The present study, providing the ecology of a major zooplankton taxon of this unique basin will be relevant for understanding the ecology and trophodynamics of the zooplankton community of the GoA. Full article

(This article belongs to the Special Issue Zooplankton Diversity in Water Bodies)

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16 pages, 3365 KiB

Open AccessFeature PaperArticle

Advanced Electrodegradation of Doxorubicin in Water Using a 3-D Ti/SnO₂ Anode

by Corina Orha, Cornelia Bandas, Carmen Lazau, Mina Ionela Popescu, Anamaria Baciu and Florica Manea

Water 2022, 14(5), 821; https://doi.org/10.3390/w14050821 - 06 Mar 2022

Cited by 8 | Viewed by 2067

Abstract

This study investigated the application of an advanced electrooxidation process with three-dimensional tin oxide deposited onto a titanium plate anode, named 3-D Ti/SnO₂, for the degradation and mineralization of one of the most important emerging contaminants with cytostatic properties, doxorubicin (DOX). [...] Read more.

This study investigated the application of an advanced electrooxidation process with three-dimensional tin oxide deposited onto a titanium plate anode, named 3-D Ti/SnO₂, for the degradation and mineralization of one of the most important emerging contaminants with cytostatic properties, doxorubicin (DOX). The anode was synthesized using a commercial Ti plate, with corrosion control in acidic medium, used as a substrate for SnO₂ deposition by the spin-coating method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses revealed that porous SnO₂ was obtained, and the rutile phase of TiO₂ was identified as an intermediary substrate onto the Ti plate. The results of CV analysis allowed us to determine the optimal operating conditions for the electrooxidation process conducted under a constant potential regime, controlled by the electron transfer or the diffusion mechanisms, involving hydroxyl radicals. The determination of UV–VIS spectra, total organic carbon (TOC), and chemical oxygen demand (COD) allowed us to identify the degradation mechanism and pathway of DOX onto the 3-D Ti/SnO₂ anode. The effective degradation and mineralization of DOX contained in water by the electrooxidation process with this new 3-D dimensionally stable anode (DSA) was demonstrated in this study. Full article

(This article belongs to the Special Issue Sustainable Wastewater Management in the Context of Circular Economy)

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11 pages, 1450 KiB

Open AccessArticle

Pollution and Release Characteristics of Nitrogen, Phosphorus and Organic Carbon in Pond Sediments in a Typical Polder Area of the Lake Taihu Basin

by Changkang Peng, Ya Gao, Yaqin Tan, Genming Sheng, Yang Yang, Jiong Huang, Dayong Sun, Daofang Zhang, Hong Tao and Feipeng Li

Water 2022, 14(5), 820; https://doi.org/10.3390/w14050820 - 06 Mar 2022

Cited by 3 | Viewed by 1999

Abstract

There is currently a lack of knowledge on the release characteristics of nutrients from artificial pond sediments in polder areas, resulting in problems in future management of such environments, including converting polders to lakes. In this study, sediment samples were taken from a [...] Read more.

There is currently a lack of knowledge on the release characteristics of nutrients from artificial pond sediments in polder areas, resulting in problems in future management of such environments, including converting polders to lakes. In this study, sediment samples were taken from a fish pond and a lotus pond in a typical polder area of the Lake Taihu Basin in China. The total nitrogen (TN, 1760–1810 mg/kg), total phosphorus (TP, 1370–1463 mg/kg) and total organic carbon (TOC, 10.1–21.2 g/kg) contents were significantly higher than those found in sediments from the adjacent aquatic system, which indicates that the legacy of agricultural activities has had an obvious cumulative effect on pond sediment nutrients. The release behavior of TN, TP and TOC varied significantly, not only under disturbed and static conditions, but also from sediments sampled at different ponds and depths. During the disturbing condition, there were continuous releases of carbon and nutrients in the lotus pond sediments, while the fish pond sediments showed a higher release at the beginning. Under static release conditions, the release of TP in the surface and bottom sediments of the fish pond increased first, then decreased and stabilized within 24 h, while the release of the lotus pond showed a slow upward trend. Despite the lower concentration of nutrients and TOC, the lotus pond sediment showed a higher release rate. The results suggested that it is necessary to adopt different strategies for different types of ponds in the project of returning polders to lakes; it is especially important to pay attention to the release of nutrients from the bottom sediments of lotus ponds in the project management. Full article

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

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12 pages, 913 KiB

Open AccessArticle

Removal of Phosphorus from Hypolimnetic Lake Water by Reactive Filter Material in a Recirculating System—Laboratory Trial

by Agnieszka Renman and Gunno Renman

Water 2022, 14(5), 819; https://doi.org/10.3390/w14050819 - 06 Mar 2022

Cited by 7 | Viewed by 2317

Abstract

A toolbox of methods must be available for the remediation of lakes and water bodies suffering from eutrophication. One method suggested is hypolimnetic withdrawal based on a closed-circuit system. Prior to the start of a pilot-scale test at Lake Hönsan, Sweden, a laboratory [...] Read more.

A toolbox of methods must be available for the remediation of lakes and water bodies suffering from eutrophication. One method suggested is hypolimnetic withdrawal based on a closed-circuit system. Prior to the start of a pilot-scale test at Lake Hönsan, Sweden, a laboratory trial with containers filled with water and bottom sediment from this lake was performed. A peristaltic pump distributed equal bottom water volume to four columns, two filled with glass beads and two with the filter material Polonite, and then back to the surface of the containers. The reactive filter medium (RFM) removed phosphate (PO₄-P) efficiently (98.6%), despite the relatively low influent concentration (390 µg L⁻¹). The control column filled with glass beads, removed 2.9% of the PO₄-P. The anoxic sediment, containing 2.47 mg P g⁻¹, released PO₄-P, which was indicated by the increased concentration in near-bottom water. The redirected water after RFM filtration had high pH (

\bar{x} = 11.1)

; however, an equalization took place in the water mass to a lower but still increased pH value

(\bar{x} = 8.7)

compared to the control

(\bar{x} = 7.02)

. This article reports the pros and cons of a full-scale system using the proposed method. Full article

(This article belongs to the Special Issue Cycling, Controlling, and Recapturing of Phosphorus in Eutrophic Waters)

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20 pages, 4566 KiB

Open AccessArticle

Analysis of the Evolution of Climatic and Hydrological Variables in the Tagus River Basin, Spain

by Gabriel Mezger, Lucia De Stefano and Marta González del Tánago

Water 2022, 14(5), 818; https://doi.org/10.3390/w14050818 - 05 Mar 2022

Cited by 7 | Viewed by 2662

Abstract

During the second half of the 20th century, several Spanish rivers experienced a decrease in the availability of water resources which coincided with an increase in human water demands. This situation is expected to be exacerbated by climate change. This study analyses the [...] Read more.

During the second half of the 20th century, several Spanish rivers experienced a decrease in the availability of water resources which coincided with an increase in human water demands. This situation is expected to be exacerbated by climate change. This study analyses the evolution of annual streamflow in 16 sub-basins of the Tagus River basin (Spain) during the 1950–2010 period and its relationship with selected variables. Our main objective is to characterize changes in in-stream flows and to identify what factors could have contributed to them. First, we used non-parametric tests to detect trends in the hydro-climatic series. Then, we analyzed changes in the runoff coefficient and applied regression-based techniques to detect anthropic drivers that could have influenced the observed trends. The analysis revealed a general decreasing trend in streamflow and an increasing trend in air temperature, while trends in precipitation are less clear. Residuals from regression models indicate that the evolution of several non-climatic factors is likely to have influenced the decline in streamflow. Our results suggest that the combination of the expansion of forested areas (a 60% increase from 1950 to 2010) and irrigated land (a 400% increase since 1950) could have played an important role in the reduction of streamflow in the Tagus basin. Full article

(This article belongs to the Special Issue Land Use-Land Cover Changes and Implications in Runoff and Flooding Phenomena)

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23 pages, 2801 KiB

Open AccessReview

Extremes Rainfall Events on Riparian Flora and Vegetation in the Mediterranean Basin: A Challenging but Completely Unexplored Theme

by Maria Silvia Pinna, Maria Cecilia Loi, Giulia Calderisi and Giuseppe Fenu

Water 2022, 14(5), 817; https://doi.org/10.3390/w14050817 - 05 Mar 2022

Cited by 7 | Viewed by 3497

Abstract

In a global climate change scenario “Extreme climatic events” are expected to widely affect flora and vegetation in Med-regions, especially “Extremes Rainfall Events” which will have impacts on riparian environments. Aiming to provide an in-depth picture on the effects of these events on [...] Read more.

In a global climate change scenario “Extreme climatic events” are expected to widely affect flora and vegetation in Med-regions, especially “Extremes Rainfall Events” which will have impacts on riparian environments. Aiming to provide an in-depth picture on the effects of these events on the riparian flora and vegetation in the Mediterranean Basin, especially focusing on islands, a bibliographic search was performed in the main international databases, which led to 571 articles published from 2000 to 2021. Most studies have analyzed these phenomena from the climatic point of view identifying three main topics “Rainfall”, “Global/Climate change”, and “Flood”. 81 papers concerned effects of extreme events on Mediterranean woodland formations and cultivated plants. A further analysis focused on European countries and Mediterranean bioregion using “Extreme rainfall events” and “Extreme rainfall and floods” as keywords. A low number of records relating to Mediterranean island regions was found, having Sicily as the study area. Moreover, seven articles had Sardinia as a study area, four of which referred to flora and vegetation. A lack of studies on the effects of extreme rainfall events on riparian flora and vegetation were highlighted. This review constitutes a call for researchers to explore extreme phenomena that have become recurrent in the Mediterranean Basin. Full article

(This article belongs to the Special Issue Conservation and Research of Aquatic Endangered Plants)

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18 pages, 6307 KiB

Open AccessFeature PaperArticle

Modified Hazelnut Shells as a Novel Adsorbent for the Removal of Nitrate from Wastewater

by Marija Stjepanović, Natalija Velić and Mirna Habuda-Stanić

Water 2022, 14(5), 816; https://doi.org/10.3390/w14050816 - 05 Mar 2022

Cited by 14 | Viewed by 2803

Abstract

The aim of the study was to prepare a novel adsorbent by chemical modification of hazelnut shells and evaluate its potential for the nitrate removal from model solutions and real wastewater. The characterization of the novel adsorbent, i.e., modified hazelnut shell (MHS) was [...] Read more.

The aim of the study was to prepare a novel adsorbent by chemical modification of hazelnut shells and evaluate its potential for the nitrate removal from model solutions and real wastewater. The characterization of the novel adsorbent, i.e., modified hazelnut shell (MHS) was performed. The adsorbent characterization included the analysis of elemental composition and the surface characteristics analysis by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The adsorption experiments (batch technique) were performed to investigate the effects of adsorbent concentration, contact time, initial nitrate concentration, and solution pH. The nitrate removal efficiency increased with the increase in MHS concentration and decreased with the initial nitrate concentration. MHS was found to be effective in nitrate removal over a wide pH range (from 2 to 10), and the highest amount of nitrate adsorbed was 25.79 mg g⁻¹ in a model nitrate solution. Depending on the aqueous medium (model solutions or real wastewater samples), it was shown that both Langmuir and Freundlich adsorption isotherm models can be used to interpret the adsorption process. It was found that the kinetics are well described by a pseudo-second order model and the nitrate adsorption process can be controlled by chemisorption. The intraparticle diffusion model has been used to identify an adsorption-controlled process by diffusion mechanisms. Adsorption/desorption experiments in column confirmed that MHS could be successfully used in multiple cycles (at least three), indicating the potential of MHS as an alternative to costly commercial adsorbents for the removal of nitrates from wastewater. Full article

(This article belongs to the Special Issue Plant- and Microbial-Based Novel Biosorbents)

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13 pages, 1672 KiB

Open AccessArticle

Effects of the Invasive Fish Species Ameiurus nebulosus on Microbial Communities in Peat Pools

by Tomasz Mieczan, Wojciech Płaska, Małgorzata Adamczuk, Magdalena Toporowska and Aleksandra Bartkowska

Water 2022, 14(5), 815; https://doi.org/10.3390/w14050815 - 05 Mar 2022

Cited by 3 | Viewed by 1589

Abstract

Disturbances in the functioning of peatlands, due to growing human impact, climate change and the appearance of alien invasive species, are becoming increasingly common. Analysis of trophic relationships in the predator (invasive alien species)–prey system is extremely important for understanding the functioning of [...] Read more.

Disturbances in the functioning of peatlands, due to growing human impact, climate change and the appearance of alien invasive species, are becoming increasingly common. Analysis of trophic relationships in the predator (invasive alien species)–prey system is extremely important for understanding the functioning of peat pools—small water bodies formed in peatlands by peat extraction. These issues are, as yet, very little understood. The aim of this study was to examine the impact of Ameiurus nebulosus, an alien and invasive fish species dominant in these pools, on the microbial communities and small metazoa (phycoflora, bacteria, heterotrophic flagellates, ciliates, and crustaceans) in peat pools. The laboratory experiment included two groups of treatments simulating natural conditions: treatments without fish and treatments with brown bullhead. The water temperature was manipulated as well. The presence of brown bullhead in combination with climate changes was shown to cause a change in the structure of microbial communities. This is reflected in a decrease in the abundance of planktonic crustaceans and an increase in ciliates. The overlapping effects of alien species and gradual climate warming may intensify the eutrophication of peatland ecosystems and the increase in the proportion of cyanobacteria, thereby affecting the carbon cycle in these ecosystems. Full article

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

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19 pages, 5284 KiB

Open AccessArticle

Dissecting the Mutual Response of Potential Evapotranspiration with Vegetation Cover/Land Use over Heilongjiang River Basin, China

by Yezhi Zhou, Juanle Wang, Elena Grigorieva and Kai Li

Water 2022, 14(5), 814; https://doi.org/10.3390/w14050814 - 05 Mar 2022

Cited by 2 | Viewed by 1823

Abstract

Spatiotemporal changes in potential evapotranspiration (PET) are important referential data for monitoring the variation in ecohydrology under climate change. As the key area of agricultural/forestry reserves and trade, research on the interactions between vegetation cover and land use with accurate PET among the [...] Read more.

Spatiotemporal changes in potential evapotranspiration (PET) are important referential data for monitoring the variation in ecohydrology under climate change. As the key area of agricultural/forestry reserves and trade, research on the interactions between vegetation cover and land use with accurate PET among the Heilongjiang River basin, China is vital for the sustainability of this cross-border region. To obtain high-suitability PET estimation based on the proven Penman–Monteith (PM) principle, two schemes were adopted using 36-year in situ meteorological data (1984–2019) and derived remote-sensing product MOD16A2 from 2001 to 2019. At meteorological sites with heterogeneous underlying surfaces, the coefficients of the evaluation factors between MOD_PET and the referrable observations were better. This suggests that remotely sensed estimation was preferentially chosen as the input to study the mutual responses. The results indicated that the annual PET and fractional vegetation cover (FVC) changes differed significantly depending on the land use. The proportions of PET according to equal intervals initially increased and then decreased with increasing vegetation coverage, and changing trends indicated a negative correlation. The strongest correlations appeared in the middle to northern sub-basins, which were affected by their distinctive climatic characteristics. The response of PET was reverse-related with changes in the area of each selected land type, but could change with the expected climatic conditions. Full article

(This article belongs to the Section Ecohydrology)

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12 pages, 2406 KiB

Open AccessFeature PaperArticle

Butyltin Contamination in Fishing Port Sediments after the Ban of Tributyltin Antifouling Paint: A Case of Qianzhen Fishing Port in Taiwan

by Shu-Hui Lee, Yung-Sheng Chen, Chih-Feng Chen, Frank Paolo Jay B. Albarico, Yee Cheng Lim, Ming-Huang Wang, Chiu-Wen Chen and Cheng-Di Dong

Water 2022, 14(5), 813; https://doi.org/10.3390/w14050813 - 05 Mar 2022

Cited by 15 | Viewed by 2635

Abstract

This study investigated the concentrations of monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) in the sediments of the Qianzhen Fishing Port (Taiwan) in 2020. Further, the pollution status, composition, and potential ecotoxicity of BTs were evaluated. This case study provides a reference for [...] Read more.

This study investigated the concentrations of monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) in the sediments of the Qianzhen Fishing Port (Taiwan) in 2020. Further, the pollution status, composition, and potential ecotoxicity of BTs were evaluated. This case study provides a reference for the benefits of the ban of TBT-based antifouling paint to date. Results showed that the total butyltin (ΣBTs, sum of TBT, DBT, and MBT) concentrations measured in the sediments of the Qianzhen Fishing Port ranged between 14.2–807 ngSn·g⁻¹ dw, with an average of 356 ± 305 ngSn·g⁻¹ dw. TBT was the most dominant species, with an average concentration of 303 ± 287 ngSn·g⁻¹ dw. This average TBT concentration is about 4.3 times lower than in 2003, showing the progress of gradual degradation of TBT in the sediments. Still, the degradation is rather slow, with a half-life of about 8.09 years. An analysis of the effects of TBT on organisms in the sediments of the Qianzhen Fishing Port was carried out according to the TBT toxicity guidelines of the US Environmental Protection Agency and the assessment class criterion for imposex (ACCI) of the Oslo and Paris Commission (OSPAR). The results showed that TBT levels in 80% of the sediments may pose negative effects on sensitive gastropods, and half of the sediments may even have an impact on gastropod reproduction. These show that marine life is still affected and threatened by TBT compounds, despite the decline of TBT concentrations since the ban of TBT-containing antifouling paints on ships in 2008. Therefore, it is necessary to continue paying attention to the changes of TBT concentrations and their potential ecological risks in the marine environment, and to formulate TBT management plans and strategies to mitigate their impacts in marine ecosystems. Full article

(This article belongs to the Special Issue The Relationship between Ships and Marine Environment)

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11 pages, 11469 KiB

Open AccessReview

Review on Per- and Poly-Fluoroalkyl Substances’ (PFASs’) Pollution Characteristics and Possible Sources in Surface Water and Precipitation of China

by Fan Wang, Yiru Zhuang, Bingqi Dong and Jing Wu

Water 2022, 14(5), 812; https://doi.org/10.3390/w14050812 - 04 Mar 2022

Cited by 10 | Viewed by 3791

Abstract

In recent years, due to the production and use of per- and poly-fluoroalkyl substances (PFASs), the research on the pollution characteristics and sources of PFASs in surface water and precipitation in China has attracted increasing attention. In this study, the related published articles [...] Read more.

In recent years, due to the production and use of per- and poly-fluoroalkyl substances (PFASs), the research on the pollution characteristics and sources of PFASs in surface water and precipitation in China has attracted increasing attention. In this study, the related published articles with sampling years from 2010 to 2020 were reviewed, and the concentration levels, composition characteristics and possible sources of PFASs in surface water (rivers and lakes) and precipitation in China were summarized, including those in the Tibetan Plateau region. The results show that the concentrations of PFASs in surface water in different areas of China vary greatly, ranging from 0.775 to 1.06 × 10⁶ ng/L. The production processes of fluorinated manufacturing facilities (FMFs) and sewage discharge from wastewater treatment plants (WWTPS) were the main sources of PFASs in surface water in China, and the concentrations of PFASs in water flowing through cities with high urbanization increased significantly compared with those before water flowed through cities with high urbanization. The compositions of PFASs in surface water gradually changed from long-chain PFASs, such as per-fluoro-octanoic acid (PFOA) and per-fluoro-octanesulfonic acid (PFOS) to short-chain PFASs, such as per-fluorobutanoic acid (PFBA), per-fluorobutanesulfonic acid (PFBS), perfluorohexanoic acid (PFHxA) and per-fluoropentanoic acid (PFPeA). The concentrations of PFASs in precipitation in China ranged from 4.2 to 191 ng/L, which were lower than those of surface water. The precipitation concentrations were relatively high around a fluorination factory and in areas with high urbanization levels. PFASs were detected in the surface water and precipitation in the Tibetan Plateau (TP), which is the global “roof of the world”, but the concentrations were low (0.115–6.34 ng/L and 0.115–1.24 ng/L, respectively). Local human activities and surface runoff were the main sources of PFASs in the surface water of the Tibetan Plateau. In addition, under the influence of the Southeast Asian monsoon in summers, marine aerosols from the Indian Ocean and air pollutants from human activities in Southeast Asia and South Asia will also enter the water bodies through dry and wet depositions. With the melting of glaciers caused by global warming, the concentration of PFASs in the surface water of the TP was higher than that before the melting of glaciers flowed into the surface water of the TP. Generally, this study summarized the existing research progress of PFAS studies on surface water and precipitation in China and identified the research gaps, which deepened the researchers’ understanding of this field and provided scientific support for related research in the future. The concentrations of PFASs in the water bodies after flowing through FMFs were significantly higher than those before water flowed through FMFs, so the discharge of the FMF production process was one of the main sources of PFASs in surface water. Full article

(This article belongs to the Special Issue Energy and Water Cycles in the Third Pole)

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5 pages, 174 KiB

Open AccessEditorial

Precipitation Measurement Instruments: Calibration, Accuracy and Performance

by Luca G. Lanza and Arianna Cauteruccio

Water 2022, 14(5), 811; https://doi.org/10.3390/w14050811 - 04 Mar 2022

Cited by 1 | Viewed by 2024

Abstract

Though ranking high among the relevant environmental variables (due to the well-known significant interactions with the everyday human life and economic activities), atmospheric precipitation is not yet measured operationally with neither the degree of accuracy that would meet the most demanding applications nor [...] Read more.

Though ranking high among the relevant environmental variables (due to the well-known significant interactions with the everyday human life and economic activities), atmospheric precipitation is not yet measured operationally with neither the degree of accuracy that would meet the most demanding applications nor any rigorous standardization framework [...] Full article

(This article belongs to the Special Issue Precipitation Measurement Instruments: Calibration, Accuracy and Performance)

11 pages, 5537 KiB

Open AccessFeature PaperArticle

Multi-Band Bathymetry Mapping with Spiking Neuron Anomaly Detection

by J. Lawen, K. Lawen, G. Salman and A. Schuster

Water 2022, 14(5), 810; https://doi.org/10.3390/w14050810 - 04 Mar 2022

Viewed by 2293

Abstract

The developed method extracts bathymetry distributions from multiple satellite image bands. The automated remote sensing function is sparsely coded and combines spiking neural net anomaly filtration, spline, and multi-band fittings. Survey data were used to identify an activation threshold, decay rate, spline fittings, [...] Read more.

The developed method extracts bathymetry distributions from multiple satellite image bands. The automated remote sensing function is sparsely coded and combines spiking neural net anomaly filtration, spline, and multi-band fittings. Survey data were used to identify an activation threshold, decay rate, spline fittings, and multi-band weighting factors. Errors were computed for remotely sensed Landsat satellite images. Multi-band fittings achieved an average error of 25.3 cm. This proved sufficiently accurate to automatically extract shorelines to eliminate land areas in bathymetry mapping. Full article

(This article belongs to the Special Issue Observations and Models for End-User Services in Coastal Marine Systems)

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19 pages, 7343 KiB

Open AccessFeature PaperArticle

Assessment of Phosphorus Input from Urban Areas in the Passaúna River and Reservoir

by Klajdi Sotiri, Regina T. Kishi, Stephan Hilgert, Mauricio B. Scheer, Pedro G. Gabriel, Diego A. Benatto and Stephan Fuchs

Water 2022, 14(5), 809; https://doi.org/10.3390/w14050809 - 04 Mar 2022

Cited by 2 | Viewed by 2035

Abstract

Elevated phosphorus loads play an important role in the deterioration of water quality and can subsequently pose a threat to the aquatic organisms in a river or a standing water body. The accurate assessment of total phosphorus (TP) fluxes from a catchment is [...] Read more.

Elevated phosphorus loads play an important role in the deterioration of water quality and can subsequently pose a threat to the aquatic organisms in a river or a standing water body. The accurate assessment of total phosphorus (TP) fluxes from a catchment is of high importance to the well-being of the entire river ecosystem. In this study, we assessed the yearly input of TP from the urban areas of the Passaúna catchment in southern Brazil. The catchment drains into the eponymous reservoir, which provides drinking water for more than 800,000 inhabitants of the Curitiba Metropolitan region. The protection of the water quality in the river as well as in the reservoir is of paramount importance, yet high phosphorous inputs have been detected. For adequate protection, the catchment emissions need to be accurately assessed. Initially, the TP concentration in the river sediment was determined in order to assess the relationship between the TP export of the urban areas and the TP stock of the river. It was found that in areas with a higher share of urban land cover and especially in areas with a lack of sewage treatment, the TP concentration in the sediment reached up to 6700 mg/kg. The assessment of the overall TP input from urban areas was based on a regionalized emission-modeling approach, combined with data from long-term water quality monitoring of the river. The monitoring station established upstream of the Passaúna Reservoir inflow provided an initial assessment and the necessary output for the validation and calibration of the model. From the drainage basin of the monitoring station, an overall TP input of 2501 kg/a (0.31 kg/(ha a)) was measured between 1 May 2018 and 1 May 2019 (3508 kg TP/a or 0.23 kg/(ha a) when extrapolating the overall catchment of the Passaúna Reservoir). The monitoring data indicated that the TP input increases during the wet months of the year. The sediment stock of the river also plays an important role in the interannual budget of TP. During the timespan of one year, many deposition–resuspension events happen. The resuspended material is included in the baseflow and hinders the differentiation between urban and nonurban input. After calibration, the model was able to predict the yearly input of TP from the urban areas of the Passaúna catchment. In addition, the share of inhabitants who are not connected to the sewer system was assessed. Overall, the combination of monitoring and modeling in this study offers a valuable overview of the TP dynamics of the system, while the model ensures reproducibility with high accuracy at the same time. Full article

(This article belongs to the Special Issue Monitoring, Modelling and Management of Water Quality II)

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24 pages, 25621 KiB

Open AccessFeature PaperArticle

Spatial and Temporal Effects of Irrigation Canals Rehabilitation on the Land and Crop Yields, a Case Study: The Nile Delta, Egypt

by Sherien Abd-Elziz, Martina Zeleňáková, Branislav Kršák and Hany F. Abd-Elhamid

Water 2022, 14(5), 808; https://doi.org/10.3390/w14050808 - 04 Mar 2022

Cited by 7 | Viewed by 3153

Abstract

Shortage of surface water is considered an international problem that has even extended to countries that have rivers, in particular countries sharing the same river basins and downstream countries, such as Egypt. This issue requires intensive management of available water resources. Irrigation Canals [...] Read more.

Shortage of surface water is considered an international problem that has even extended to countries that have rivers, in particular countries sharing the same river basins and downstream countries, such as Egypt. This issue requires intensive management of available water resources. Irrigation Canals Rehabilitation (ICR) has become essential to protect surface water in irrigation canals from losses due to seepage. Egypt is one of the countries that has started using this technique. This paper aims to evaluate the impact of ICR using concrete on the land and on crop yields. The SEEP/W model is used in the current study to estimate changes in the groundwater table and moisture in the root zone. Three cases studies have been simulated and compared including unlined, lined, and lined canals with a drainage pipe. The methodology is applied to three canals in the Nile Delta: Sero, Dafan, and New-Aslogy. The results demonstrate that ICR has decreased the losses from canals which resulted in lowering the groundwater, where the case of lining gave a higher reduction than the case of lining with a drainage pipe. In addition, the water table underneath the embankment was lowered. Decreasing the groundwater table could help to protect the land from logging and increase crop yields, but it may reduce the recharging of groundwater aquifers. Such a study is highly recommended in arid regions to decrease water losses where many countries are suffering from water shortage. Full article

(This article belongs to the Special Issue Assessment and Management of Hydrological Risks Due to Climate Change)

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14 pages, 1877 KiB

Open AccessArticle

Analysis of the Relative Importance of the Main Hydrological Processes at Different Temporal Scales in Watersheds of South-Central Chile

by Yelena Medina, Enrique Muñoz, Robert Clasing and José Luis Arumí

Water 2022, 14(5), 807; https://doi.org/10.3390/w14050807 - 04 Mar 2022

Cited by 3 | Viewed by 2188

Abstract

In Chile in recent years, changes in precipitation and temperatures have been reported that could affect water resource management and planning. One way of facing these changes is studying and understanding the behavior of hydrological processes at a regional scale and their different [...] Read more.

In Chile in recent years, changes in precipitation and temperatures have been reported that could affect water resource management and planning. One way of facing these changes is studying and understanding the behavior of hydrological processes at a regional scale and their different temporal scales. Therefore, the objective of this study is to analyze the importance of the hydrological processes of the HBV model at different temporal scales and for different hydrological regimes. To this end, 88 watersheds located in south-central Chile were analyzed using time-varying sensitivity analysis at five different temporal scales (1 month, 3 months, 6 months, 1 year, and 5 years). The results show that the model detects the temporality of the most important hydrological processes. In watersheds with a pluvial regime, the greater the temporal scale, the greater the importance of soil water accumulation processes and the lower the importance of surface runoff processes. By contrast, in watersheds with a nival regime, at greater temporal scales, groundwater accumulation and release processes take on greater importance, and soil water release processes are less important. Full article

(This article belongs to the Special Issue Climate Changes and Hydrological Processes)

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16 pages, 4836 KiB

Open AccessArticle

Challenges in Interpreting Geochemical Data: An Appraisal of Analytical Techniques Applied to a Karstic Lake Sediment Record

by Aritina Haliuc, Alicja Bonk, Jack Longman, Simon M. Hutchinson, Michal Zak and Daniel Veres

Water 2022, 14(5), 806; https://doi.org/10.3390/w14050806 - 04 Mar 2022

Viewed by 2739

Abstract

The paleoclimatic and paleoenvironmental changes inferred from shifts in lake sediment geochemistry require reliable, efficient and cost-effective methods of analysis. The available geochemical techniques, however, suggest that different analytical approaches can influence data interpretation. X-ray fluorescence core scanner analyses (XRF-CS), field portable X-ray [...] Read more.

The paleoclimatic and paleoenvironmental changes inferred from shifts in lake sediment geochemistry require reliable, efficient and cost-effective methods of analysis. The available geochemical techniques, however, suggest that different analytical approaches can influence data interpretation. X-ray fluorescence core scanner analyses (XRF-CS), field portable X-ray fluorescence (FPXRF) and inductively coupled plasma optical emission spectrometry (ICP-OES) were concurrently applied to provide a multi-method geochemical appraisal of a 6000-year-long karstic sediment record (Lake Ighiel, Romania). The comparison between techniques was based on a set of elements that are widely employed in environmental reconstructions (Ti, K, Fe, Ca). Descriptive and statistical approaches were used to assess the advantages and disadvantages of each method and assess their optimal use in karstic environments. Our data display similar downcore patterns, with strong to moderate correlations between the datasets. The discrepancies observed between method-specific downcore multi element behaviour are related to the preparation steps and sampling. To best capture the complexity of past environmental changes in karstic settings, a combination of quantitative and qualitative geochemical methods would be the most appropriate approach to reliable data acquisition and subsequent paleoenvironmental interpretation of lake sediment data. Full article

(This article belongs to the Special Issue Research on Karst Eco-Hydrology and Sediment)

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