Water

19 pages, 2690 KiB

Open AccessArticle

Detecting the Planform Changes Due to the Seasonal Flow Fluctuation and 2012 Severe Flood in the Amazon River near Iquitos City, Peru Based on Remote Sensing Image Analysis

by Karen Garcia Angulo and Kwan Tun Lee

Water 2022, 14(3), 509; https://doi.org/10.3390/w14030509 - 8 Feb 2022

Cited by 2 | Viewed by 2821

Abstract

The Upper Amazon River forms an anabranching planform, which has been found to have significant changes in migration rate and river morphology. Previous studies have elaborated long-term evolution of the anabranching systems; however, research on the influence of the water level on temporal [...] Read more.

The Upper Amazon River forms an anabranching planform, which has been found to have significant changes in migration rate and river morphology. Previous studies have elaborated long-term evolution of the anabranching systems; however, research on the influence of the water level on temporal changes in anabranching is absent. According to the theory of river hydraulics, fluvial scour usually occurs when the shear force possessed by the high flow exceeds the resistance of the streambank. In contrast, deposition occurs when the tractive force of the low flow is insufficient to overcome the forces of gravity and friction. This study investigated the Muyuy anabranching planform change of the Upper Peruvian Amazon River due to the seasonal flow fluctuations and a severe flood in 2012. The Muyuy anabranching area is located 20 km upstream of Iquitos City, Peru. Landsat images from the wet and dry seasons in 2008, 2009, 2012, and 2013 were collected. The images were classified into three land cover classes (water, bare soil, vegetation and others) based on NDVI analysis. Quantitative analysis of the erosion/deposition shows that deposition is more noticeable than erosion in the Muyuy anabranching area. Considerable deposition can be found on the island of the anabranching system, and the streambank erosion occurred in the outer (concave) side of the main channel. This phenomenon of river erosion and deposition consistently occurred in 2008 and 2009 because of the periodical variation among the wet and dry seasons. However, prominent erosion was observed in 2012 and it was recognized to be caused by the severe flood. Furthermore, the extensive island was formed in 2013, which means substantial depositions accumulated in the recession of the 2012 flood. Full article

(This article belongs to the Special Issue Large Rivers in a Changing Environment)

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16 pages, 3288 KiB

Open AccessArticle

Dynamic Adsorption Characteristics of Phosphorus Using MBCQ

by Qihui Liang, Xinxi Fu, Ping Wang, Xinxian Li and Peiyuan Zheng

Water 2022, 14(3), 508; https://doi.org/10.3390/w14030508 - 8 Feb 2022

Cited by 11 | Viewed by 2712

Abstract

Biochar is a new type of adsorption material with excellent performance, but it has some problems, such as light texture, poor sedimentation, and difficult recovery, which limits its practical application. In this study, biochar microspheres (MBCQ) were prepared by the sol–gel method using [...] Read more.

Biochar is a new type of adsorption material with excellent performance, but it has some problems, such as light texture, poor sedimentation, and difficult recovery, which limits its practical application. In this study, biochar microspheres (MBCQ) were prepared by the sol–gel method using powdery biochar from Hydrocotyle vulgaris as raw material and sodium alginate as a granular carrier. Experiments were performed to investigate the dynamic adsorption characteristics of phosphorus by MBCQ in the adsorption column and the influences of particle size, initial phosphorus concentration, flow rate, and column height on the breakthrough curve. The results showed that the static adsorption properties of different particles varied and that 3-millimeter particles were optimal. The breakthrough time positively correlated with column height and negatively correlated with initial phosphorus concentration, flow rate, and particle size. Flow velocity significantly impacted breakthrough time and length of mass transfer. The bed depth/service time model accurately predicted the relationship between breakthrough times and column heights. When c_t/c₀ = 0.6, the average relative deviation between predicted and measured values was the lowest. The Thomas model described the MBCQ adsorption process of Ph (R² > 0.95), which indicated that diffusion in MBCQ adsorption was not a rate-limiting step. Full article

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

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11 pages, 9764 KiB

Open AccessArticle

Permanganate/Bisulfite Pre-Oxidation of Natural Organic Matter Enhances Nitrogenous Disinfection By-Products Formation during Subsequent Chlorination

by Shu He and Nanqi Ren

Water 2022, 14(3), 507; https://doi.org/10.3390/w14030507 - 8 Feb 2022

Cited by 2 | Viewed by 2215

Abstract

The permanganate/bisulfite (PM/BS) process is a novel oxidation process, which can degrade micropollutants within several seconds. As natural organic matter (NOM) ubiquitously exists in an aquatic environment, the PM/BS process will inevitably react with NOM, which may impact the disinfection-by-products (DBPs) formation during [...] Read more.

The permanganate/bisulfite (PM/BS) process is a novel oxidation process, which can degrade micropollutants within several seconds. As natural organic matter (NOM) ubiquitously exists in an aquatic environment, the PM/BS process will inevitably react with NOM, which may impact the disinfection-by-products (DBPs) formation during subsequent chlorination. This study investigated the effect of PM/BS pre-oxidation of NOM on DBP formation. It was found that TOC removal reached a plateau when the molar ratio of PM to BS was 1:5. Increasing ratios of PM to BS decreased the intensity and area of fluorescence spectroscopy. PM and BS doses, pre-oxidation time, pH of solutions and concentration of Br⁻ impacted the formation potential of various DBPs. PM/BS pre-oxidation decreased the formation of TCM while increasing the yields of N-DBPs, thus increasing the risk of water quality. Calculated toxicity analysis showed that a general increase in CTI was observed with PM/BS pre-oxidation, indicating that PM/BS pre-oxidation had a negative effect on risk control of overall cytotoxicity. Although the PM/BS process could accelerate the degradation of micropollutants, the elevated DBPs formation, especially highly toxic N-DBPs, needs enough attention to control water-quality risk. Full article

(This article belongs to the Special Issue Formation and Control of Disinfection By-Products in Water)

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14 pages, 5534 KiB

Open AccessArticle

Insights into Shallow Freshwater Lakes Hydrology in the Yangtze Floodplain from Stable Water Isotope Tracers

by Jing Li, Fan Song, Zhicheng Bao, Hongxiang Fan and Huawu Wu

Water 2022, 14(3), 506; https://doi.org/10.3390/w14030506 - 8 Feb 2022

Cited by 5 | Viewed by 2233

Abstract

Stable isotopes of lake waters are widely used to identify the relative importance of hydrological processes on the lake water balance across the ungauged landscape via the coupled-isotope tracer model. The isotopic compositions of twenty shallow freshwater lakes across the mid-lower reaches of [...] Read more.

Stable isotopes of lake waters are widely used to identify the relative importance of hydrological processes on the lake water balance across the ungauged landscape via the coupled-isotope tracer model. The isotopic compositions of twenty shallow freshwater lakes across the mid-lower reaches of Yangtze floodplain (MLY) were investigated in January and May of 2018. The lake-specific input water (δ_I) and evaporation-to-inflow (E/I) ratios were estimated to explore the specific lake hydrology across the MLY. Results showed that distinct isotopic enrichment trends in May compared with those in January, which was indicative of stronger evaporation in May. The δ¹⁸O_I values of specific lakes exhibited large variability across the MLY, which may be related to the watershed properties, such as watershed area and elevation, and rainfall. The estimated E/I ratios of lakes across the MLY were below 1, which suggested that these lakes (code 1–15) are flood-dominated in the middle reaches of Yangtze River where lakes are susceptible to Three Gorges Dams regulations. By contrast, the relatively lower variability of lake E/I ratios were observed from the Yangtze River Delta (code 17–20) because these lakes with developed river network systems are highly exchanged by artificial regulation. Our investigation of lake types and corresponding isotopic evolution patterns are likely typical of other floodplain landscapes and their identification could be used to better predict hydrological responses to ongoing climate change and artificial regulations by dams. Full article

(This article belongs to the Special Issue Isotope Tracers in Watershed Hydrology)

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12 pages, 2499 KiB

Open AccessArticle

Wastewater Treatment Using Novel Magnetic Nanosponges

by Tilak Chhetri, Gary Cunningham, Dhananjay Suresh, Bruce Shanks, Raghuraman Kannan, Anandhi Upendran and Zahra Afrasiabi

Water 2022, 14(3), 505; https://doi.org/10.3390/w14030505 - 8 Feb 2022

Cited by 11 | Viewed by 4570

Abstract

Modern agricultural activities and concentrated animal feeding operations (CAFOs) are two of the major sources of groundwater contamination that affect the quality of drinking water. Conventional water quality improvement methods include direct filtration, coagulation/settling treatment techniques, membrane-based systems, and absorption-based systems. However, to [...] Read more.

Modern agricultural activities and concentrated animal feeding operations (CAFOs) are two of the major sources of groundwater contamination that affect the quality of drinking water. Conventional water quality improvement methods include direct filtration, coagulation/settling treatment techniques, membrane-based systems, and absorption-based systems. However, to date, there are no efficient and cost-effective processes available for water treatment. This study developed an innovative nanotechnology-based technique to improve groundwater quality. Magnetic nanosponges (MNSs) were synthesized and characterized using two different magnetic nanoparticles along with polymeric coagulants. The efficiency of MNSs in removing pollutants in wastewater collected from local diary and swine CAFO lagoons was investigated. Standard water quality evaluation parameters, such as the total organic content (TOC), turbidity, total suspended solids (TSS), and biological oxygen demand (BOD), were measured prior to and after treatment with MNSs. The results demonstrate the potential of MNSs to improve the quality of groundwater and support the development of a cost-effective best management practice (BMP) that also employs traditional coagulants at CAFOs and other wastewater treatment plants. Full article

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13 pages, 3895 KiB

Open AccessArticle

Facile Synthesis of MOFs-Templated Carbon Aerogels with Enhanced Tetracycline Adsorption Performance

by Yan Kong, Kun Han, Yuan Zhuang and Baoyou Shi

Water 2022, 14(3), 504; https://doi.org/10.3390/w14030504 - 8 Feb 2022

Cited by 17 | Viewed by 2627

Abstract

Three-dimensional aerogels have great potential for antibiotic removal from aqueous solution due to their excellent solution mass transfer channels and special morphology. Herein, the metal ions were bound with alginate to form alginate-Fe, alginate-Cu, and alginate-Fe-Cu hydrogels, then they were used as nucleation [...] Read more.

Three-dimensional aerogels have great potential for antibiotic removal from aqueous solution due to their excellent solution mass transfer channels and special morphology. Herein, the metal ions were bound with alginate to form alginate-Fe, alginate-Cu, and alginate-Fe-Cu hydrogels, then they were used as nucleation sites for metal organic framework (MOF) growth to obtain MAlgs gels, respectively. Considering the aqueous environmental stability of MOFs particles, the alginate and MOF particles in MAlgs aerogels were pyrolyzed as templates to obtain the derived carbon aerogel CMAlgs. The results showed that the adsorption capacity of MAlgs-Fe-Cu aerogel was higher than that of MAlg-Cu and MAlg-Fe aerogels, up to ~130 mg·g⁻¹. The adsorption performance of carbon aerogel CMAlg-Cu decreased obviously because of the decrease of pore size and oxygen-containing functional groups. The adsorption process is a combination of physical adsorption and chemical adsorption. In addition, CMAlgs aerogels exhibit better recyclability than MAlgs aerogels. This work provides a new strategy for fabricating MOFs-templated in-situ grown carbon aerogels for water purification. Full article

(This article belongs to the Special Issue Carbon Neutrality and Wastewater Treatment)

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11 pages, 4436 KiB

Open AccessArticle

Degradation Kinetics and Disinfection By-Product Formation of Iopromide during UV/Chlorination and UV/Persulfate Oxidation

by Chenyan Hu, Qiangbing Wang, Yi-Li Lin, Yeye Zhu, Cun Xiong, Dandan Huang and Ling Xu

Water 2022, 14(3), 503; https://doi.org/10.3390/w14030503 - 8 Feb 2022

Cited by 5 | Viewed by 2832

Abstract

As the detection of micropollutants in various water resources is commonly reported, developing an efficient technology to remove them to maintain water safety has become a major focus in recent years. The degradation kinetics of iopromide, one of a group of iodinated X-ray [...] Read more.

As the detection of micropollutants in various water resources is commonly reported, developing an efficient technology to remove them to maintain water safety has become a major focus in recent years. The degradation kinetics of iopromide, one of a group of iodinated X-ray contrast media (ICM), using advanced oxidation processes of ultraviolet/chlorination (UV/Cl₂) and UV/persulfate (UV/PS) oxidation were investigated in this research. The results show that iopromide degradation fitted pseudo-first-order kinetics, and the rate constants were calculated as 2.20 (± 0.01) × 10⁻¹ min⁻¹ and 6.08 (± 0.10) × 10⁻² min⁻¹ in UV/Cl₂ and UV/PS, respectively. In the two systems, the degradation rates were positively correlated with the initial concentrations of HOCl and PS, respectively. In the UV/Cl₂ system, the degradation rate of iopromide reached a maximum at pH 7, while in the UV/PS system, pH had only a slight effect on the degradation rate. Chloride in water had a negligible effect on iopromide degradation, whereas bromide inhibited iopromide degradation in the UV/Cl₂ system. The contributions of UV irradiation, •OH, and RCS to iopromide degradation during UV/Cl₂ treatment were calculated as 20.8%, 54.1%, and 25.1%, respectively. One carbonated and three nitrogenated disinfection by-products (C-DBP (chloroform) and N-DBPs (dichloroacetonitrile, trichloronitromethane, and trichloroacetone)) were detected at relatively high levels, along with three emerging iodinated DBPs (dichloroiodomethane, monochlorodiiodomethane, and triiodomethane). More C- and N-DBPs were generated in the UV/Cl₂ and UV/PS systems than in UV irradiation, while considerably higher I-DBPs were generated in UV irradiation than in the other two systems. Thus, it is essential to pay attention to DBP formation when UV/Cl₂ or UV/PS is used to treat iopromide in water. In order to better control the generation of carcinogenic and toxic I-DBPs, Cl₂ or PS combined with UV should be adopted for iopromide degradation, instead of UV alone, for providing safe drinking water to the public. Full article

(This article belongs to the Special Issue Application of UV Technologies in Water and Wastewater Treatment)

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16 pages, 4790 KiB

Open AccessFeature PaperArticle

Assessment of Spatio-Temporal Variability of Faecal Pollution along Coastal Waters during and after Rainfall Events

by Elena Manini, Elisa Baldrighi, Fabio Ricci, Federica Grilli, Donato Giovannelli, Michele Intoccia, Silvia Casabianca, Samuela Capellacci, Nadia Marinchel, Pierluigi Penna, Fabrizio Moro, Alessandra Campanelli, Angelina Cordone, Monica Correggia, Deborah Bastoni, Luigi Bolognini, Mauro Marini and Antonella Penna

Water 2022, 14(3), 502; https://doi.org/10.3390/w14030502 - 8 Feb 2022

Cited by 26 | Viewed by 3903

Abstract

More than 80% of wastewaters are discharged into rivers or seas, with a negative impact on water quality along the coast due to the presence of potential pathogens of faecal origin. Escherichia coli and enterococci are important indicators to assess, monitor, and predict [...] Read more.

More than 80% of wastewaters are discharged into rivers or seas, with a negative impact on water quality along the coast due to the presence of potential pathogens of faecal origin. Escherichia coli and enterococci are important indicators to assess, monitor, and predict microbial water quality in natural ecosystems. During rainfall events, the amount of wastewater delivered to rivers and coastal systems is increased dramatically. This study implements measures capable of monitoring the pathways of wastewater discharge to rivers and the transport of faecal bacteria to the coastal area during and following extreme rainfall events. Spatio-temporal variability of faecal microorganisms and their relationship with environmental variables and sewage outflow in an area located in the western Adriatic coast (Fano, Italy) was monitored. The daily monitoring during the rainy events was carried out for two summer seasons, for a total of five sampling periods. These results highlight that faecal microbial contaminations were related to rainy events with a high flow of wastewater, with recovery times for the microbiological indicators varying between 24 and 72 h and influenced by a dynamic dispersion. The positive correlation between ammonium and faecal bacteria at the Arzilla River and the consequences in seawater can provide a theoretical basis for controlling ammonium levels in rivers as a proxy to monitor the potential risk of bathing waters pathogen pollution. Full article

(This article belongs to the Special Issue The Impact of Treated Urban Wastewaters and Flood Discharge on the Quality of the Bathing Water)

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17 pages, 1972 KiB

Open AccessFeature PaperArticle

An Underestimated Contribution of Deltaic Denitrification in Reducing Nitrate Export to the Coastal Zone (Po River–Adriatic Sea, Northern Italy)

by Maria Pia Gervasio, Elisa Soana, Fabio Vincenzi and Giuseppe Castaldelli

Water 2022, 14(3), 501; https://doi.org/10.3390/w14030501 - 8 Feb 2022

Cited by 5 | Viewed by 2957

Abstract

In transitional environments, the role of sediments biogeochemistry and denitrification is crucial for establishing their buffer potential against nitrate (NO₃⁻) pollution. The Po River (Northern Italy) is a worldwide hotspot of eutrophication. However, benthic N dynamics and the relevance of [...] Read more.

In transitional environments, the role of sediments biogeochemistry and denitrification is crucial for establishing their buffer potential against nitrate (NO₃⁻) pollution. The Po River (Northern Italy) is a worldwide hotspot of eutrophication. However, benthic N dynamics and the relevance of denitrification in its delta have not yet been described. The aim of the present study was to quantify the contribution of denitrification in attenuating the NO₃⁻ loading transported to the sea during summer. Benthic fluxes of dissolved inorganic nitrogen (N) and denitrification rates were measured in laboratory incubations of intact sediment cores collected, along a salinity gradient, at three sections of the Po di Goro, the southernmost arm of the Po Delta. The correlation between NO₃⁻ consumption and N₂ production rates demonstrated that denitrification was the main process responsible for reactive N removal. Denitrification was stimulated by both NO₃⁻ availability in the Po River water and organic enrichment of sediment likely determined by salinity-induced flocculation of particulate organic load, and inhibited by increasing salinity, along the river–sea gradient. Overall, denitrification represented a sink of approximately 30% of the daily N loading transported in middle summer, highlighting a previously underestimated role of the Po River Delta. Full article

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

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15 pages, 9915 KiB

Open AccessArticle

Turbulent Flow Structures in Developing and Fully-Developed Flows under the Impact of Downward Seepage

by Anurag Sharma, Bimlesh Kumar and Giuseppe Oliveto

Water 2022, 14(3), 500; https://doi.org/10.3390/w14030500 - 8 Feb 2022

Cited by 2 | Viewed by 2592

Abstract

This work experimentally investigates the turbulent flow characteristics of developing and fully-developed flows over a rough bed channel that is subjected to downward seepage. Instantaneous 3D velocities were collected using an acoustic Doppler velocimeter (ADV) in the developing and fully-developed flow regions, along [...] Read more.

This work experimentally investigates the turbulent flow characteristics of developing and fully-developed flows over a rough bed channel that is subjected to downward seepage. Instantaneous 3D velocities were collected using an acoustic Doppler velocimeter (ADV) in the developing and fully-developed flow regions, along the channel centerline, to analyze different turbulent statistics. Observations revealed that the streamwise and vertical velocities were higher in developing flows, whereas the Reynolds shear stresses, and turbulence intensities, were smaller. The downward seepage would affect the velocity distributions and flow depth in both the developing and fully-developed regions. Therefore, new equations to represent the distribution of the turbulence intensities were proposed, and a comparison with the current literature is provided. The investigation of the Reynolds stress anisotropy tensors concludes that the degree of anisotropy in fully-developed flows is lower than for developing flows. Full article

(This article belongs to the Special Issue Research on Hydraulics and River Dynamics)

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17 pages, 2419 KiB

Open AccessArticle

A Collaborative Framework for Hydropower Development and Sustainable Livelihood of Farmers in the Lancang-Mekong River Basin: A Review with the Perspective of Energy-Water-Food Nexus

by Shuai Zhong, Yidong Zhu, Jianan Zhao and Lei Shen

Water 2022, 14(3), 499; https://doi.org/10.3390/w14030499 - 7 Feb 2022

Cited by 5 | Viewed by 3663

Abstract

With the process of poverty eradication and economic growth, hydropower development becomes increasingly important because of its huge potential advantages in the Lancang-Mekong River Basin. However, the complex topography and rich resource endowments in the Lancang-Mekong River Basin bring a variety of potential [...] Read more.

With the process of poverty eradication and economic growth, hydropower development becomes increasingly important because of its huge potential advantages in the Lancang-Mekong River Basin. However, the complex topography and rich resource endowments in the Lancang-Mekong River Basin bring a variety of potential risks and uncertainties in hydropower development, which has an important impact on the sustainable livelihood of farmers. There is an urgent need for countries in the Lancang-Mekong River Basin to systematically assess hydropower projects, especially their impact on the sustainable livelihoods of farmers. Based on the systematic analysis of relevant literature, this study established a collaborative framework of hydropower development and farmers’ sustainable livelihood, including theoretical framework, indicator system and model structure. The purpose is to explore the interaction mechanism of energy and water resources utilization, food security and sustainable livelihood of farmers in hydropower development. The findings can provide scientific and technological support for the Belt and Road Initiative, poverty reduction and sustainable development in the river basin. Full article

(This article belongs to the Collection Water Policy Collection)

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13 pages, 2846 KiB

Open AccessArticle

Spatial and Temporal Variations in Fish Assemblage in Feitsui Reservoir, in Northern Taiwan, from 2006–2020

by Chen Yi-Ron, Hou Wen-Shang, Huang Chen-Kang and Chou Chu-Yang

Water 2022, 14(3), 498; https://doi.org/10.3390/w14030498 - 7 Feb 2022

Cited by 3 | Viewed by 2134

Abstract

Reservoirs are artificial ecosystems that modify the hydrological and environmental components nearby. The long-term monitoring of fish assemblages in reservoirs may provide key information to understand how these artificial ecosystems allow fish population fluctuations and identify proper conservation strategies. A sentinel-site approach method [...] Read more.

Reservoirs are artificial ecosystems that modify the hydrological and environmental components nearby. The long-term monitoring of fish assemblages in reservoirs may provide key information to understand how these artificial ecosystems allow fish population fluctuations and identify proper conservation strategies. A sentinel-site approach method assessed changes in fish assemblages in the Feitsui Reservoir (1024 ha) over 14 years, including the periods 2006–2008, 2010–2011, 2016, 2018, and 2020. Fish assemblages, sampled using gill nets, were composed of 38 species (12 families and 8 orders) with Cyprinidae as the dominant family; the fish fauna were dominated by species of the family Cyprinidae (71%) and Cichlidae (20.3%). Principal component analysis and nonmetric multidimensional scaling categorized the assemblages into two groups (cold and warm seasons), and we identified three parameters that were significantly correlated with the season (p < 0.05): SD (R = −0.04), Chl-a (R = 0.01), and algal count (R = 0.19); the algal count was higher in the warm season than in the cold season. The fish assemblage in the cold and warm seasons contained no exclusive taxa, contributing to the dissimilarity between the groups. The fish assemblage for the years before and after 2010 indicated partial overlap between the two groups; S. macrops contributed greatly to the separation of the two periods (>10% each; SIMPER) and O. mossambicus was dominant in assemblage structures after 2010. Our findings show the importance of long-term fish monitoring for the investigation of the effects of nonnative fish species on native fish species composition. Full article

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

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21 pages, 25196 KiB

Open AccessFeature PaperArticle

An Insight into the Factors Controlling Delta Flood Events: The Case of the Evros River Deltaic Plain (NE Aegean Sea)

by Serafeim Poulos, Aikaterini Karditsa, Maria Hatzaki, Athina Tsapanou, Christos Papapostolou and Konstantinos Chouvardas

Water 2022, 14(3), 497; https://doi.org/10.3390/w14030497 - 7 Feb 2022

Cited by 3 | Viewed by 2703

Abstract

The present contribution aims to give an insight into the main terrestrial and marine processes leading to delta flooding in the case of the transboundary Evros delta, located at the microtidal NE Aegean Sea, on the basis of recorded flood events in the [...] Read more.

The present contribution aims to give an insight into the main terrestrial and marine processes leading to delta flooding in the case of the transboundary Evros delta, located at the microtidal NE Aegean Sea, on the basis of recorded flood events in the Evros deltaic plain. The prevailing weather conditions at the onset of the event, along with sea-level rise above the mean state, portray the mechanism for the development of compound flood events and subsequent riparian flooding. This system blocks the riverine water’s seaward exit, resulting in the flooding of the lower deltaic plain. The river discharge is recognized as a secondary factor acting mainly toward the persistence of the events. Several limitations restrict the quantification potential of the relative contribution of the key factors to the development, onset, and duration of a flood. Mitigation of the impacts of such flood events requires intercountry cooperation and a management plan based on a network of environmental monitoring. Full article

(This article belongs to the Special Issue Coastal and Continental Shelf Dynamics in a Changing Climate)

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16 pages, 3690 KiB

Open AccessArticle

Spatiotemporal Analysis of Drought and Agriculture Standardized Residual Yield Series Nexuses across Punjab, Pakistan

by Muhammad Waseem, Ali Hasan Jaffry, Muhammad Azam, Ijaz Ahmad, Adnan Abbas and Jae-Eun Lee

Water 2022, 14(3), 496; https://doi.org/10.3390/w14030496 - 7 Feb 2022

Cited by 19 | Viewed by 5393

Abstract

Food security for the growing global population is closely associated with the variations in agricultural yield at the regional scale. Based on this perspective, the current study was designed to determine the impacts of drought on wheat production in the Punjab province, which [...] Read more.

Food security for the growing global population is closely associated with the variations in agricultural yield at the regional scale. Based on this perspective, the current study was designed to determine the impacts of drought on wheat production in the Punjab province, which is the agricultural hub of Pakistan. Wheat is a staple food in Pakistan, and Punjab provides a major contribution to the total wheat production of the country. Therefore, Punjab is vital to scientific concerns regarding the evaluation of climatic impacts on the annual wheat yield. The current study offers a better understanding of the drought impacts on wheat in Punjab during 2001–2019. The Standardized Precipitation Index was used to assess the impact of drought stress on the wheat yield. Its temporal evolution indicates the recurrent appearance of drought episodes during the wheat cropping season. Furthermore, meteorological drought was noticed in all study years except for 2019. The results reveal that 2002 experienced severe drought conditions. The frequency of drought was calculated as 29% for SPI-12. The relationships between soil moisture, the Standardized Yield Residual Series (SYRS), and the detrended SPI at lags of 1–12 months indicate that zones 1 and 2 are more sensitive to dry conditions. The results presented in this study provide evidence to authorities responsible for developing policies in the context of natural hazards, particularly droughts, and for preparing drought mitigation plans and implementing the adaptation strategies to minimize the effects of drought on wheat yields. Full article

(This article belongs to the Special Issue The Impacts of Climate Change on Hydrologic Extremes)

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14 pages, 2119 KiB

Open AccessArticle

Characteristic and Attribution of Runoff Variation in the Yanhe River Basin, Loess Plateau, Based on the Budyko Hypothesis

by Kun Hou, Jiping Wang and Xiuru Wang

Water 2022, 14(3), 495; https://doi.org/10.3390/w14030495 - 7 Feb 2022

Cited by 8 | Viewed by 2287

Abstract

The ecological restoration projects in the Loess Plateau (LP) has significantly altered the underlying surface conditions, coupled with a warming–wetting climate, which has profoundly affected the regional water cycle. Evaluating the response of runoff to external environmental change and quantitatively identifying the contribution [...] Read more.

The ecological restoration projects in the Loess Plateau (LP) has significantly altered the underlying surface conditions, coupled with a warming–wetting climate, which has profoundly affected the regional water cycle. Evaluating the response of runoff to external environmental change and quantitatively identifying the contribution of anthropogenic interference and climate change are prerequisites for efficient utilization of water resources in arid/semi-arid regions. Daily recorded data of hydrological and meteorological elements between 1969 and 2019 and the elasticity coefficient method based on Budyko hypothesis were used for attribution analysis of runoff change in the Yanhe River basin. The results show the following: (1) the measured runoff decreased significantly (p < 0.05, –0.2845 mm year⁻¹), and suggested substantial difference before and after 2000; (2) the area of woodland and grassland had a sharp increase from 2000, while the elasticity of runoff to precipitation, potential evapotranspiration (ET₀), and vegetation all decreased; (3) the improvement of underlying surface conditions has become the leading factor of runoff reduction with a contribution of 96.78%; (4) the impact of vegetation restoration on runoff reduction is effective within a certain threshold. We consider that more attention should be paid to the afforestation scale and its possible negative eco-hydrological effects in future ecological restoration. Full article

(This article belongs to the Topic Water Management in the Era of Climatic Change)

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18 pages, 4080 KiB

Open AccessArticle

Assessment of Seasonal Drought Impact on Potato in the Northern Single Cropping Area of China

by Dao Riao, Xingpeng Liu, Suri Guga, Jie Xu, Kaiwei Li, Mingxi Zhang and Jiquan Zhang

Water 2022, 14(3), 494; https://doi.org/10.3390/w14030494 - 7 Feb 2022

Cited by 1 | Viewed by 1989

Abstract

Drought is one of the key limiting factors for potato yield in the northern single cropping area (NSCA) in China. To analyze the impact of drought on potato yield in the NSCA, this study first analyzed the variation of dry/wet conditions in the [...] Read more.

Drought is one of the key limiting factors for potato yield in the northern single cropping area (NSCA) in China. To analyze the impact of drought on potato yield in the NSCA, this study first analyzed the variation of dry/wet conditions in the plantable areas on a seasonal scale using the standardized precipitation evapotranspiration index (SPEI). Secondly, the changes in yield structure in the last 36 years were systematically analyzed and divided the total yield change into planting area contribution and climate yield contribution. Finally, a regression model of the seasonal drought index and contributing factors of total yield change in different administrative regions was constructed. The results showed that the main factors affecting the total potato yield of the NSCA began to change from yield to planting area in the 1990s, while the barycenter of the output structure and population moved to the southwest, with grassland being the main source; dry/wet conditions (year i) had varying degrees of effect on contributing factors (year i, year i + 1) of total yield change in different administrative regions that were not limited to the growing season; the non-overlap of high-yield area, high-adaptability area and planting area was the urgent problem to be solved for the NSCA. The results of this study can provide a scientific basis for NSCA crop management and communication with farmers, providing new ideas for sustainable production in other agricultural regions in the world. Full article

(This article belongs to the Special Issue Water and Soil Resources Management in Agricultural Areas)

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25 pages, 2090 KiB

Open AccessFeature PaperArticle

Scour Propagation Rates around Offshore Pipelines Exposed to Currents by Applying Data-Driven Models

by Mohammad Najafzadeh and Giuseppe Oliveto

Water 2022, 14(3), 493; https://doi.org/10.3390/w14030493 - 7 Feb 2022

Cited by 13 | Viewed by 2456

Abstract

Offshore pipelines are occasionally exposed to scouring processes; detrimental impacts on their safety are inevitable. The process of scouring propagation around offshore pipelines is naturally complex and is mainly due to currents and/or waves. There is a considerable demand for the safe design [...] Read more.

Offshore pipelines are occasionally exposed to scouring processes; detrimental impacts on their safety are inevitable. The process of scouring propagation around offshore pipelines is naturally complex and is mainly due to currents and/or waves. There is a considerable demand for the safe design of offshore pipelines exposed to scouring phenomena. Therefore, scouring propagation patterns must be focused on. In the present research, machine learning (ML) models are applied to achieve equations for the prediction of the scouring propagation rate around pipelines due to currents. The approaching flow Froude number, the ratio of embedment depth to pipeline diameter, the Shields parameter, and the current angle of attack to the pipeline were considered the main dimensionless factors from the reliable literature. ML models were developed based on various setting parameters and optimization strategies coming from evolutionary and classification contents. Moreover, the explicit equations yielded from ML models were used to demonstrate how the proposed approaches are in harmony with experimental observations. The performance of ML models was assessed utilizing statistical benchmarks. The results revealed that the equations given by ML models provided reliable and physically consistent predictions of scouring propagation rates regarding their comparison with scouring tests. Full article

(This article belongs to the Special Issue Erosion and Sediment Transport Processes in Coastal Waters)

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20 pages, 14840 KiB

Open AccessEditor’s ChoiceArticle

A Stacking Ensemble Learning Model for Monthly Rainfall Prediction in the Taihu Basin, China

by Jiayue Gu, Shuguang Liu, Zhengzheng Zhou, Sergey R. Chalov and Qi Zhuang

Water 2022, 14(3), 492; https://doi.org/10.3390/w14030492 - 7 Feb 2022

Cited by 47 | Viewed by 5131

Abstract

The prediction of monthly rainfall is greatly beneficial for water resources management and flood control projects. Machine learning (ML) techniques, as an increasingly popular approach, have been applied in diverse climatic regions, showing their respective superiority. On top of that, the ensemble learning [...] Read more.

The prediction of monthly rainfall is greatly beneficial for water resources management and flood control projects. Machine learning (ML) techniques, as an increasingly popular approach, have been applied in diverse climatic regions, showing their respective superiority. On top of that, the ensemble learning model that synthesizes the advantages of different ML models deserves more attention. In this study, an ensemble learning model based on stacking approach was proposed. Four prevalent ML models, namely k-nearest neighbors (KNN), extreme gradient boosting (XGB), support vector regression (SVR), and artificial neural networks (ANN) are taken as base models. To combine the outputs from the base models, the weighting algorithm is used as second-layer learner to generate predictions. Large-scale climate indices, large-scale atmospheric variables, and local meteorological variables were used as predictors. R², RMSE and MAE, were used as evaluation metrics. The results show that the performance of base models varied among the nine stations in the Taihu Basin, while the stacking approach generally performed better than the four base models. The stacking model showed better performance in spring and winter than in summer and autumn. During wet months, the accuracy of model prediction varied more significantly. On the whole, based on performance evaluation measures, it is concluded that the proposed stacking ensemble multi-ML model can provide a flexible and reasonable prediction framework applicable to other regions. Full article

(This article belongs to the Special Issue Statistics in Hydrology)

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17 pages, 3640 KiB

Open AccessArticle

Evaluating Permeable Clay Brick Pavement for Pollutant Removal from Varying Strength Stormwaters in Arid Regions

by Md. Shafiquzzaman, Saad Mohammed A. Alqarawi, Husnain Haider, Md. Rafiquzzaman, Meshal Almoshaogeh, Fawaz Alharbi and Yassine El-Ghoul

Water 2022, 14(3), 491; https://doi.org/10.3390/w14030491 - 7 Feb 2022

Cited by 5 | Viewed by 2699

Abstract

Permeable pavement is a low impact development technology for stormwater (SW) runoff control and pollutant removal. The strength of SW depends on land use of the catchment, e.g., semi-urban vs. industrial. The performance (in terms of pollutants removal) of permeable clay bricks (PCB) [...] Read more.

Permeable pavement is a low impact development technology for stormwater (SW) runoff control and pollutant removal. The strength of SW depends on land use of the catchment, e.g., semi-urban vs. industrial. The performance (in terms of pollutants removal) of permeable clay bricks (PCB) has not been adequately assessed for SW of varying strengths. For using the permeable clay bricks as a pavement surface layer, the present research investigates its pollutant removal capacity through SW infiltration using a laboratory setup. SW samples of two different strengths, i.e., high polluted stormwater (HPSW) and less polluted stormwater (LPSW), were tested for a pavement system consisting of the clay brick layer on top of a coarse gravel support layer. The tests were performed at a rainfall intensity of 12.5 mm/h (for a 10-year return period in Buraidah, Qassim) to evaluate the suitability of PCB for the arid and semi-arid regions. The experiments revealed that PCB became fully saturated and achieved a steady-state outflow condition after 10 min of rainfall. Irrespective of contamination level, the pollutant removal efficiency was found to be similar for both HPSW and LPSW. High TSS (>98%) and turbidity (>99%) removals were achieved for both strengths, while BOD5 (78.4%) and COD (76.1%) removals were moderate. Poor to moderate nutrient removal, 30.5% and 39.1% for total nitrogen (TN) and 34.7% and 31.3% for total phosphorus (TP), respectively for HPSW and LPSW, indicates an adsorptive removal of nutrients in the system. Heavy metal removal efficiency ranged from 6.7% to 94%, with higher removals archived for Fe, Mn, Se, and Pb. The study provides insights into the role of PCB as a surface layer in the permeable pavement for pollutant removal. The study also establishes the guidelines for the optimal permeable pavement design to deal with SW of varying contamination levels. Permeable clay bricks showed the potential to be used as a sustainable LID technology for arid regions. Full article

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

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21 pages, 3339 KiB

Open AccessArticle

Daily Streamflow Forecasting Based on the Hybrid Particle Swarm Optimization and Long Short-Term Memory Model in the Orontes Basin

by Huseyin Cagan Kilinc

Water 2022, 14(3), 490; https://doi.org/10.3390/w14030490 - 7 Feb 2022

Cited by 29 | Viewed by 5051

Abstract

Water, a renewable but limited resource, is vital for all living creatures. Increasing demand makes the sustainability of water resources crucial. River flow management, one of the key drivers of sustainability, will be vital to protect communities from the worst impacts on the [...] Read more.

Water, a renewable but limited resource, is vital for all living creatures. Increasing demand makes the sustainability of water resources crucial. River flow management, one of the key drivers of sustainability, will be vital to protect communities from the worst impacts on the environment. Modelling and estimating river flow in the hydrological process is crucial in terms of effective planning, management, and sustainable use of water resources. Therefore, in this study, a hybrid approach integrating long short-term memory networks (LSTM) and particle swarm algorithm (PSO) was proposed. For this purpose, three hydrological stations were utilized in the study along the Orontes River basin, Karasu, Demirköprü, and Samandağ, respectively. The timespan of Demirköprü and Karasu stations in the study was between 2010 and 2019. Samandağ station data were from 2009–2018. The datasets consisted of daily flow values. In order to validate the performance of the model, the first 80% of the data were used for training, and the remaining 20% were used for the testing of the three FMSs. Statistical methods such as linear regression and the more classical model autoregressive integrated moving average (ARIMA) were used during the comparison process to assess the proposed method’s performance and demonstrate its superior predictive ability. The estimation results of the models were evaluated with RMSE, MAE, MAPE, SD, and R² statistical metrics. The comparison of daily streamflow predictions results revealed that the PSO-LSTM model provided promising accuracy results and presented higher performance compared with the benchmark and linear regression models. Full article

(This article belongs to the Special Issue Advances in Water Use Efficiency in a Changing Environment)

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15 pages, 4227 KiB

Open AccessArticle

Combination of Microscopic Tests of the Activated Sludge and Effluent Quality for More Efficient On-Site Treatment

by Agnieszka Karczmarczyk and Weronika Kowalik

Water 2022, 14(3), 489; https://doi.org/10.3390/w14030489 - 7 Feb 2022

Cited by 6 | Viewed by 3146

Abstract

Container on-site wastewater treatment plants are systems of growing interest in the areas where sewer systems cannot be implemented. In this study, container on-site wastewater treatment plant with low-loaded activated sludge has been examined. The aim of the study was: (i) to assess [...] Read more.

Container on-site wastewater treatment plants are systems of growing interest in the areas where sewer systems cannot be implemented. In this study, container on-site wastewater treatment plant with low-loaded activated sludge has been examined. The aim of the study was: (i) to assess the efficiency of the plant; and (ii) to evaluate the relationship between the condition of activated sludge and selected parameters of effluent quality. Effluent quality has been characterized by the reliability factor (RF) and technological purity index (TPI). Sludge quality assessment covered measurements of volume (Vo), dry matter (DM), sludge index (SI), and the unit oxygen consumption rate (UOCR). Microscopic analysis has been performed to assess the morphological (flocks) and biotic quality (sludge biotic index, SBI) of activated sludge. The research has been completed by an on-site measurement of dissolved oxygen concentration in an activated sludge chamber with 30 s intervals. Results confirmed a significant (p < 0.05) correlation (CC = −0.9277) between biochemical oxygen demand (BOD₅) and SBI for the oxygen level in the aeration chamber between 1–2 mg/L. Negative significant correlation (p < 0.05) has also been found between SBI and electrical conductivity (EC) (CC = −0.7478). In the examined case, the optimal EC of the effluent was in the range of 600–800 µS/cm. Full article

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

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19 pages, 1706 KiB

Open AccessArticle

Simulating Discharge in a Non-Dammed River of Southeastern South America Using SWAT Model

by Thais Fujita, Marcos Vinicius Bueno de Morais, Vanessa Cristina Dos Santos, Anderson Paulo Rudke, Marilia Moreira de Eiras, Ana Carolina Freitas Xavier, Sameh Adib Abou Rafee, Eliane Barbosa Santos, Leila Droprinchinski Martins, Cintia Bertacchi Uvo, Rodrigo Augusto Ferreira de Souza, Edmilson Dias de Freitas and Jorge Alberto Martins

Water 2022, 14(3), 488; https://doi.org/10.3390/w14030488 - 7 Feb 2022

Cited by 3 | Viewed by 2919

Abstract

Within a single region, it is possible to identify opposite changes in flow production. This proved to be the case for several basins in southeastern South America. It remains challenging to the causes this behavior and whether changes in streamflow will continue at [...] Read more.

Within a single region, it is possible to identify opposite changes in flow production. This proved to be the case for several basins in southeastern South America. It remains challenging to the causes this behavior and whether changes in streamflow will continue at current levels or decline in the coming decades. In this study, we used the Soil Water Assessment Tool to simulate monthly river discharge in the Ivaí River Basin, an unregulated medium-sized catchment and tributary of the Upper Paraná River Basin. After calibration, the simulated flow regime for the five streamflow stations based on the Nash-Sutcliffe Efficiency index (NSE) rated four of the streamflow stations Very Good (NSE between 0.86 and 0.89) and only one in the Good index (0.70). The overall flow behavior was well represented, although an underestimation was identified in four monitoring stations. Through assessment of its functionality and limitations in terms of specific flow duration curves percentages, the calibrated model could provide (to managers) the reliability needed for a realistic intervention. The results of this study may assist managers and support public policies for the use of water resources at the Ivaí River basin. Full article

(This article belongs to the Special Issue Advances and Challenges in Hydrological Modeling and Engineering)

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12 pages, 1206 KiB

Open AccessArticle

The Diversity of Phytoplankton in a Combined Rice-Shrimp Farming System in the Coastal Area of the Vietnamese Mekong Delta

by Nguyen Dinh Giang Nam, Nguyen Thanh Giao, Minh N. Nguyen, Nigel K. Downes, Nguyen Vo Chau Ngan, Le Hoang Hai Anh and Nguyen Hieu Trung

Water 2022, 14(3), 487; https://doi.org/10.3390/w14030487 - 7 Feb 2022

Cited by 4 | Viewed by 2510

Abstract

An assessment of varying density, species composition and dynamics of phytoplankton in a combined rice-shrimp culture was carried out in My Xuyen district, Soc Trang province in the Vietnamese Mekong delta. Water was sampled six times at six separate locations within the culture [...] Read more.

An assessment of varying density, species composition and dynamics of phytoplankton in a combined rice-shrimp culture was carried out in My Xuyen district, Soc Trang province in the Vietnamese Mekong delta. Water was sampled six times at six separate locations within the culture system, on days 1, 20, 34, 57, 68, and day 81 of the rice-shrimp crop cycle. The results showed the abundance of 95 phytoplankton species belonging to five phyla including Cyanophyta, Chlorophyta, Bacillariophyta, Euglenophyta, and Pyrrophyta. The values of Shannon–Wiener index indicated high phytoplankton diversity, while the water quality ranged from medium to good. A Cluster Analysis showed that the phytoplankton density variation can be divided into three distinct periods. The initial phase of crop growth was dominated by Pandorina morum, Pediastrum simplex, Eudorina elegans, Oscillatoria limosa, and Anabaena circinalis. The midstage, reproductive phase of crop growth was dominated by Scenedesnus acuminatus, Pediastrum duplex, Closterinm setaceum, Scenedesnus quadricauda, and Actinastnum hantzschii. Whereas Scenedesnus acuminatus, Scenedesnus quadricauda, Closterinm closterioides, Staurastrum arcuatum, Euglena nhrenbergii, and Phacus lnsmorensis were dominant at the end of crop cycle. The findings provide useful information on phytoplankton assemblages in a typical rice-shrimp culture, which has recently gained popularity as an adaptive livelihood system. Full article

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

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20 pages, 1486 KiB

Open AccessArticle

Towards a Good Ecological Status? The Prospects for the Third Implementation Cycle of the EU Water Framework Directive in The Netherlands

by Nick van Kats, Carel Dieperink, Marleen van Rijswick and Lisette de Senerpont Domis

Water 2022, 14(3), 486; https://doi.org/10.3390/w14030486 - 7 Feb 2022

Cited by 6 | Viewed by 4181

Abstract

The aim of the EU Water Framework Directive (WFD) is to achieve a “good” chemical and ecological status for all waters by 2027. Currently, the Netherlands and other EU Member States are finalizing their plans for the third iteration of the WFD management [...] Read more.

The aim of the EU Water Framework Directive (WFD) is to achieve a “good” chemical and ecological status for all waters by 2027. Currently, the Netherlands and other EU Member States are finalizing their plans for the third iteration of the WFD management cycle. In this paper, we conducted an ex ante evaluation of these plans by assessing the perceptions of regional water authorities on goal attainment and the factors that account for it. In order to gain these insights, we first reviewed literature and developed a framework of factors that stimulate or hamper the implementation of the WFD. More detailed insights into the relevance and characteristics of these factors were found by applying the framework in two in-depth case studies. A more generalizable pattern was found by translating the case study results into a survey among the regional water authorities. We found that the majority of the participating water authorities expect that 50% (or more) of their WFD objectives will be achieved in 2027. However, hampering factors such as a lack of political will or the impossibility to address key causes of the problems that were identified during earlier management cycles are still present. Since it is doubtful whether they can be addressed by regional water authorities, we conclude that it will be unlikely that ecological ambitions will be met by 2027. Full article

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

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14 pages, 8785 KiB

Open AccessArticle

Baseflow Separation Using the Digital Filter Method: Review and Sensitivity Analysis

by Taeuk Kang, Sangho Lee, Namjoo Lee and Youngkyu Jin

Water 2022, 14(3), 485; https://doi.org/10.3390/w14030485 - 7 Feb 2022

Cited by 12 | Viewed by 5973

Abstract

The baseflow separation method based on a digital filter is a simple method for separating the baseflow from streamflow. Appropriate estimation of filter parameters is required to use the digital filter method for analysis. We carried out sensitivity analysis on four digital filter [...] Read more.

The baseflow separation method based on a digital filter is a simple method for separating the baseflow from streamflow. Appropriate estimation of filter parameters is required to use the digital filter method for analysis. We carried out sensitivity analysis on four digital filter methods: Lyne–Hollick (LH), Chapman, Chapman and Maxwell (CM), and exponentially weighted moving average (EWMA). Furthermore, appropriate filter parameters were suggested for each method in this study. By applying them to 25 stage stations in the Nakdong River in the Republic of Korea, the four methods were evaluated. The results of the evaluation showed that the Chapman and CM methods had problems separating the baseflow during the dry seasons. The EWMA and LH methods were able to achieve reliable baseflow separation of the outcomes by selecting appropriate the filter parameters. Thus, the EWMA and LH methods can be used easily and reasonably among the digital filter methods that have one filter parameter. Full article

(This article belongs to the Special Issue Advances in Hydroinformatics for Water Data Management and Analysis)

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17 pages, 3215 KiB

Open AccessArticle

Zerovalent Iron Nanoparticles-Alginate Nanocomposites for Cr(VI) Removal in Water—Influence of Temperature, pH, Dissolved Oxygen, Matrix, and nZVI Surface Composition

by Marguerite Parnis, Fabiana Elena García, Melanie Victoria Toledo, Víctor Nahuel Montesinos and Natalia Quici

Water 2022, 14(3), 484; https://doi.org/10.3390/w14030484 - 7 Feb 2022

Cited by 6 | Viewed by 3331

Abstract

The immobilization of zerovalent iron nanoparticles (nZVI) is a way to facilitate their use in continuous flow systems for the treatment of aqueous pollutants. In this work, two types of nZVI (powdered, NSTAR; and slurry suspended, N25) were immobilized in millimetric alginate beads [...] Read more.

The immobilization of zerovalent iron nanoparticles (nZVI) is a way to facilitate their use in continuous flow systems for the treatment of aqueous pollutants. In this work, two types of nZVI (powdered, NSTAR; and slurry suspended, N25) were immobilized in millimetric alginate beads (AL) by coagulation, forming nanocomposites (NCs). These NCs, N25@AL and NSTAR@AL, were structurally studied and tested for Cr(VI) removal. For both NCs types, SEM analysis showed a uniform distribution of the nanoparticles in micron-scale agglomerates, and XRD analysis revealed the preservation of α-Fe as the main iron phase of the immobilized nanoparticles. Additionally, Raman spectroscopy results evidenced a partial oxidation of the initially present magnetite. For both nZVI types, the Cr(VI) removal efficiency increased with temperature, decreased with pH, and did not show any significant change in anoxic or oxic conditions. On the other hand, N25@AL resulted a faster removal agent than NSTAR@AL; however, both materials had the same maximum removal capacity: 133 mg of Cr(VI) per gram of nZVI at pH 3. Cr(III) formed during the removal of Cr(VI) was retained by the alginate matrix, constituting a clear advantage against the use of free nZVI in suspension at acidic pH. Full article

(This article belongs to the Special Issue Application of Nanomaterials in Water Treatment)

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23 pages, 9259 KiB

Open AccessArticle

Groundwater Suitability for Drinking and Irrigation Using Water Quality Indices and Multivariate Modeling in Makkah Al-Mukarramah Province, Saudi Arabia

by Maged El Osta, Milad Masoud, Abdulaziz Alqarawy, Salah Elsayed and Mohamed Gad

Water 2022, 14(3), 483; https://doi.org/10.3390/w14030483 - 6 Feb 2022

Cited by 92 | Viewed by 7111

Abstract

Water shortage and quality are major issues in many places, particularly arid and semi-arid regions such as Makkah Al-Mukarramah province, Saudi Arabia. The current work was conducted to examine the geochemical mechanisms influencing the chemistry of groundwater and assess groundwater resources through several [...] Read more.

Water shortage and quality are major issues in many places, particularly arid and semi-arid regions such as Makkah Al-Mukarramah province, Saudi Arabia. The current work was conducted to examine the geochemical mechanisms influencing the chemistry of groundwater and assess groundwater resources through several water quality indices (WQIs), GIS methods, and the partial least squares regression model (PLSR). For that, 59 groundwater wells were tested for different physical and chemical parameters using conventional analytical procedures. The results showed that the average content of ions was as follows: Na⁺ > Ca²⁺ > Mg ²⁺ > K⁺ and Cl⁻ > SO₄²⁻ > HCO₃²⁻ > NO₃⁻ > CO₃⁻. Under the stress of evaporation and saltwater intrusion associated with the reverse ion exchange process, the predominant hydrochemical facies were Ca-HCO₃, Na-Cl, mixed Ca-Mg-Cl-SO₄, and Na-Ca-HCO₃. The drinking water quality index (DWQI) has indicated that only 5% of the wells were categorized under good to excellent for drinking while the majority (95%) were poor to unsuitable for drinking, and required appropriate treatment. Furthermore, the irrigation water quality index (IWQI) has indicated that 45.5% of the wells were classified under high to severe restriction for agriculture, and can be utilized only for high salt tolerant plants. The majority (54.5%) were deemed moderate to no restriction for irrigation, with no toxicity concern for most plants. Agriculture indicators such as total dissolved solids (TDS), potential salinity (PS), sodium absorption ratio (SAR), and residual sodium carbonate (RSC) had mean values of 2572.30, 33.32, 4.84, and −21.14, respectively. However, the quality of the groundwater in the study area improves with increased rainfall and thus recharging the Quaternary aquifer. The PLSR models, which are based on physicochemical characteristics, have been shown to be the most efficient as alternative techniques for determining the six WQIs. For instance, the PLSR models of all IWQs had determination coefficients values of R² ranging between 0.848 and 0.999 in the Cal., and between 0.848 and 0.999 in the Val. datasets, and had model accuracy varying from 0.824 to 0.999 in the Cal., and from 0.817 to 0.989 in the Val. datasets. In conclusion, the combination of physicochemical parameters, WQIs, and multivariate modeling with statistical analysis and GIS tools is a successful and adaptable methodology that provides a comprehensive picture of groundwater quality and governing mechanisms. Full article

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

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14 pages, 2864 KiB

Open AccessTechnical Note

Surface Drainage Systems Operating during Heavy Rainfall—A Comparative Analysis between Two Small Flysch Catchments Located in Different Physiographic Regions of the Western Carpathians (Poland)

by Rafał Kroczak, Tomasz Bryndal and Józef Żychowski

Water 2022, 14(3), 482; https://doi.org/10.3390/w14030482 - 6 Feb 2022

Cited by 2 | Viewed by 2170

Abstract

In this study, the river system and the surface drainage system (SDS) operating during heavy rainfall in two Carpathian catchments located in foothills and medium-high mountain areas were compared. The results revealed that regardless of the differences in the river systems and physiographical [...] Read more.

In this study, the river system and the surface drainage system (SDS) operating during heavy rainfall in two Carpathian catchments located in foothills and medium-high mountain areas were compared. The results revealed that regardless of the differences in the river systems and physiographical parameters of the catchments, the SDS operating during heavy rainfall becomes similar. This similarity is reflected in the density of the SDS (11.5–12.2 km·km⁻²) and the structure of the SDS, confirmed by Hortonian-type analysis. This similarity in the SDS was discussed in the context of the geomorphological transformation of the hillslopes and the hydrological response of a catchment to heavy rainfall. Full article

(This article belongs to the Section Hydrology)

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14 pages, 1933 KiB

Open AccessArticle

The Dynamics Characteristics of Soil Water Infiltration and Capillary Rise for Saline–Sodic Soil Mixed with Sediment

by Chitao Sun, Di Feng, Chao Yu, Jingsheng Sun, Xin Han, Mingming Zhang, Peng Zhang, Huifang Han, Weibing Mao and Xiaojun Shen

Water 2022, 14(3), 481; https://doi.org/10.3390/w14030481 - 6 Feb 2022

Cited by 2 | Viewed by 2999

Abstract

Yellow River sediment is the potential resource for saline–sodic soil reclamation. Experiments of one-dimensional soil columns were conducted to investigate the upward and downward soil water transportation characteristics for saline–sodic soil mixed with different sediment addition (0, 10, 20 kg/m² in the [...] Read more.

Yellow River sediment is the potential resource for saline–sodic soil reclamation. Experiments of one-dimensional soil columns were conducted to investigate the upward and downward soil water transportation characteristics for saline–sodic soil mixed with different sediment addition (0, 10, 20 kg/m² in the top 20 cm layer). The saturated hydraulic conductivity, ratio of macroporosity, cumulative capillary adsorption and infiltration rate all increased with the increase in sediment addition. No significant differences were detected for both the initial capillary rise rate and the initial infiltration rate for the upward and downward water transportation treatments, respectively. The average adsorption and infiltration rates showed an increasing trend with the increased sediment addition. The initial and average infiltration rates were higher than the initial capillary rise rate and average adsorption rates. The Philip model seems the optimal choice for the dynamic simulation of both upward and downward soil water transportation. The results may provide useful information for soil salinization amelioration. Full article

(This article belongs to the Special Issue Water and Soil Resources Management in Agricultural Areas)

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23 pages, 10990 KiB

Open AccessArticle

The Lower Havel River Region (Brandenburg, Germany): A 230-Year-Long Historical Map Record Indicates a Decrease in Surface Water Areas and Groundwater Levels

by Christoph Zielhofer, Johannes Schmidt, Niklas Reiche, Marie Tautenhahn, Helen Ballasus, Michael Burkart, Anja Linstädter, Elisabeth Dietze, Knut Kaiser and Natascha Mehler

Water 2022, 14(3), 480; https://doi.org/10.3390/w14030480 - 6 Feb 2022

Cited by 6 | Viewed by 4127

Abstract

Instrumental data show that the groundwater and lake levels in Northeast Germany have decreased over the past decades, and this process has accelerated over the past few years. In addition to global warming, the direct influence of humans on the local water balance [...] Read more.

Instrumental data show that the groundwater and lake levels in Northeast Germany have decreased over the past decades, and this process has accelerated over the past few years. In addition to global warming, the direct influence of humans on the local water balance is suspected to be the cause. Since the instrumental data usually go back only a few decades, little is known about the multidecadal to centennial-scale trend, which also takes long-term climate variation and the long-term influence by humans on the water balance into account. This study aims to quantitatively reconstruct the surface water areas in the Lower Havel Inner Delta and of adjacent Lake Gülpe in Brandenburg. The analysis includes the calculation of surface water areas from historical and modern maps from 1797 to 2020. The major finding is that surface water areas have decreased by approximately 30% since the pre-industrial period, with the decline being continuous. Our data show that the comprehensive measures in Lower Havel hydro-engineering correspond with groundwater lowering that started before recent global warming. Further, large-scale melioration measures with increasing water demands in the upstream wetlands beginning from the 1960s to the 1980s may have amplified the decline in downstream surface water areas. Full article

(This article belongs to the Section Hydrology)

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