Water

24 pages, 32820 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Experimental and Numerical Study of the Effects of Geometric Appendance Elements on Energy Dissipation over Stepped Spillway

by Amir Ghaderi and Saeed Abbasi

Water 2021, 13(7), 957; https://doi.org/10.3390/w13070957 - 31 Mar 2021

Cited by 23 | Viewed by 5000

Abstract

In the stepped spillway, the steps, by providing an artificial roughening bed, dissipate the flow of energy more than other types of spillways, so the construction costs for stilling basin are reduced. However, what is important in this type of spillway is increasing [...] Read more.

In the stepped spillway, the steps, by providing an artificial roughening bed, dissipate the flow of energy more than other types of spillways, so the construction costs for stilling basin are reduced. However, what is important in this type of spillway is increasing the effectiveness of steps in the rate of energy dissipation. The present study deals with experimental and numerical simulations regarding the influence of geometric appendance elements on the steps and its impact on the energy dissipation performances, flow patterns properties, turbulent kinetic energy, flow resistance and the Darcy roughness. The localization of inception point of air entrainment is also assessed. To this aim, different configurations are taken into account. The computational procedure is validated with experimental results and then used to test the hydraulic behavior of different geometric configurations. The results showed that the appendance elements on the steps increased the turbulent kinetic energy (TKE) values and Darcy–Weisbach friction and the energy dissipation increased significantly. By reducing the height of the elements, energy dissipation and the TKE value increase more significantly. With the appendance elements on step, the air entrainment inception locations a positioning further upstream than the flat step stepped spillway. Full article

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

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20 pages, 5031 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Assessing Natural Background Levels in the Groundwater Bodies of the Apulia Region (Southern Italy)

by Rita Masciale, Stefano Amalfitano, Eleonora Frollini, Stefano Ghergo, Marco Melita, Daniele Parrone, Elisabetta Preziosi, Michele Vurro, Annamaria Zoppini and Giuseppe Passarella

Water 2021, 13(7), 958; https://doi.org/10.3390/w13070958 - 31 Mar 2021

Cited by 21 | Viewed by 4150

Abstract

Defining natural background levels (NBL) of geochemical parameters in groundwater is a key element for establishing threshold values and assessing the environmental state of groundwater bodies (GWBs). In the Apulia region (Italy), carbonate sequences and clastic sediments host the 29 regional GWBs. In [...] Read more.

Defining natural background levels (NBL) of geochemical parameters in groundwater is a key element for establishing threshold values and assessing the environmental state of groundwater bodies (GWBs). In the Apulia region (Italy), carbonate sequences and clastic sediments host the 29 regional GWBs. In this study, we applied the Italian guidelines for the assessment of the NBLs, implementing the EU Water Framework Directive, in a south-European region characterized by the typical Mediterranean climatic and hydrologic features. Inorganic compounds were analyzed at GWB scale using groundwater quality data measured half-yearly from 1995 to 2018 in the regional groundwater monitoring network (341 wells and 20 springs). Nitrates, chloride, sulfate, boron, iron, manganese and sporadically fluorides, boron, selenium, arsenic, exceed the national standards, likely due to salt contamination along the coast, agricultural practices or natural reasons. Monitoring sites impacted by evident anthropic activities were excluded from the dataset prior to NBL calculation using a web-based software tool implemented to automate the procedure. The NBLs resulted larger than the law limits for iron, manganese, chlorides, and sulfates. This methodology is suitable to be applied in Mediterranean coastal areas with high anthropic impact and overexploitation of groundwater for agricultural needs. The NBL definition can be considered one of the pillars for sustainable and long-term groundwater management by tracing a clear boundary between natural and anthropic impacts. Full article

(This article belongs to the Special Issue Natural Background Levels in Groundwater)

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15 pages, 23755 KiB

Open AccessEditor’s ChoiceArticle

Migration of ²³⁸U and ²²⁶Ra Radionuclides in Technogenic Permafrost Taiga Landscapes of Southern Yakutia, Russia

by Aleksandr Chevychelov, Petr Sobakin, Aleksey Gorokhov, Lubov Kuznetsova and Aleksey Alekseev

Water 2021, 13(7), 966; https://doi.org/10.3390/w13070966 - 31 Mar 2021

Cited by 6 | Viewed by 3165

Abstract

This article describes the features and migration patterns of natural long-lived heavy radionuclides ²³⁸U and ²²⁶Ra in the major components of the environment including rocks, river waters, soils, and vegetation of permafrost taiga landscapes of Southern Yakutia, which helped us to [...] Read more.

This article describes the features and migration patterns of natural long-lived heavy radionuclides ²³⁸U and ²²⁶Ra in the major components of the environment including rocks, river waters, soils, and vegetation of permafrost taiga landscapes of Southern Yakutia, which helped us to understand the scale and levels of their radioactive contamination. Different methods have been used in this study to determine the content of ²³⁸U and ²²⁶Ra in various samples, including gamma-ray spectrometry, X-ray spectroscopy, laser excited luminescence, and emanation method. It was determined that the main source of radioactive pollution of soil and vegetation cover, as well as surface waters in these technogenic landscapes, are the dumps of radioactive rock that were formed here as the result of geological exploration carried out in this area during the last third of the 20th century. The rocks studied were initially characterized by a coarse, mainly stony gravelly composition and contrasting radiation parameters, where the gamma radiation exposure rate varied between 1.71 and 16.7 µSv/h, and the contents of ²³⁸U and ²²⁶Ra were within the range 126–1620 mg/kg and 428–5508 × 10⁻⁷ mg/kg, respectively, and the ²²⁶Ra: ²³⁸U ratio was 1.0. This ratio shifted later on from the equilibrium state towards the excess of either ²³⁸U or ²²⁶Ra, due to the processes of air, water, and biogenic migration. Two types of ²³⁸U and ²²⁶Ra radionuclides migration were observed in studied soils, namely aerotechnogenic and hydrotechnogenic, each of which results in a different intraprofile radionuclide distribution and different levels of radioactive contamination. In this study, we also identified plants capable of selective accumulation of certain radionuclides, including Siberian mountain ash (Sorbus sibiricus), which selectively absorbs ²²⁶Ra, and terrestrial green and aquatic mosses, which accumulate significant amounts of ²³⁸U. Full article

(This article belongs to the Special Issue Geochemistry of Landscape and Soil)

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18 pages, 4131 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Hydroclimatic Variability and Land Cover Transformations in the Central Italian Alps

by Matteo Balistrocchi, Massimo Tomirotti, Alessandro Muraca and Roberto Ranzi

Water 2021, 13(7), 963; https://doi.org/10.3390/w13070963 - 31 Mar 2021

Cited by 7 | Viewed by 4354

Abstract

Extreme streamflow nonstationarity has probably attracted more attention than mean streamflow nonstationarity in the assessment of the impacts of climate change on the water cycle. Nonetheless, a significant decrease in mean streamflow could lead to conditions of scarcity of freshwater in the long-term [...] Read more.

Extreme streamflow nonstationarity has probably attracted more attention than mean streamflow nonstationarity in the assessment of the impacts of climate change on the water cycle. Nonetheless, a significant decrease in mean streamflow could lead to conditions of scarcity of freshwater in the long-term period, seriously compromising the sustainability of the demand for civil, agricultural, and industrial uses. Regional analyses are useful to better characterize an area’s nonstationarity, since a clear trend at a global scale has not been detected yet. In this article, long-term and high-quality series of streamflow discharges observed in five rivers in the Central Italian Alps, including two multicentury series and two new precipitation and streamflow series not analyzed before, are investigated to statistically characterize individual trends of mean annual runoff volumes. Nonparametric pooled statistics are also introduced to assess the regional trend. Additional climatic and nonclimatic factors, namely, precipitation trends and land cover transformations, have also been considered as potential change drivers. Unlike precipitation, runoff volumes show a marked and statistically significant decrease of −1.45 mm/year, which appears to be homogeneous in the region. The land cover transformation analysis presented here revealed extensive woodland expansions of 510 km² in 2018 out of the 2650 km² area measured in 1954, representing 38% of the area investigated in this study: this anthropic driver of enhanced hydrologic losses can be recognized as an additional likely cause for the regional runoff volume decrease. Full article

(This article belongs to the Special Issue Climate Change Impact and Adaptation in Water Resources Management)

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10 pages, 1584 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Mapping the Pollution Plume Using the Self-Potential Geophysical Method: Case of Oum Azza Landfill, Rabat, Morocco

by Meryem Touzani, Ismail Mohsine, Jamila Ouardi, Ilias Kacimi, Moad Morarech, Mohamed Habib El Bahajji, Tarik Bouramtane, Abdessamad Tiouiouine, Suzanne Yameogo and Badr El Mahrad

Water 2021, 13(7), 961; https://doi.org/10.3390/w13070961 - 31 Mar 2021

Cited by 10 | Viewed by 3972

Abstract

The main landfill in the city of Rabat (Morocco) is based on sandy material containing the shallow Mio-Pliocene aquifer. The presence of a pollution plume is likely, but its extent is not known. Measurements of spontaneous potential (SP) from the soil surface were [...] Read more.

The main landfill in the city of Rabat (Morocco) is based on sandy material containing the shallow Mio-Pliocene aquifer. The presence of a pollution plume is likely, but its extent is not known. Measurements of spontaneous potential (SP) from the soil surface were cross-referenced with direct measurements of the water table and leachates (pH, redox potential, electrical conductivity) according to the available accesses, as well as with an analysis of the landscape and the water table flows. With a few precautions during data acquisition on this resistive terrain, the results made it possible to separate the electrokinetic (~30%) and electrochemical (~70%) components responsible for the range of potentials observed (70 mV). The plume is detected in the hydrogeological downstream of the discharge, but is captured by the natural drainage network and does not extend further under the hills. Full article

(This article belongs to the Special Issue Modeling and Prediction of Groundwater Contaminant Plumes)

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25 pages, 7592 KiB

Open AccessEditor’s ChoiceArticle

Impact of Dataset Size on the Signature-Based Calibration of a Hydrological Model

by Safa A. Mohammed, Dimitri P. Solomatine, Markus Hrachowitz and Mohamed A. Hamouda

Water 2021, 13(7), 970; https://doi.org/10.3390/w13070970 - 31 Mar 2021

Cited by 8 | Viewed by 3993

Abstract

Many calibrated hydrological models are inconsistent with the behavioral functions of catchments and do not fully represent the catchments’ underlying processes despite their seemingly adequate performance, if measured by traditional statistical error metrics. Using such metrics for calibration is hindered if only short-term [...] Read more.

Many calibrated hydrological models are inconsistent with the behavioral functions of catchments and do not fully represent the catchments’ underlying processes despite their seemingly adequate performance, if measured by traditional statistical error metrics. Using such metrics for calibration is hindered if only short-term data are available. This study investigated the influence of varying lengths of streamflow observation records on model calibration and evaluated the usefulness of a signature-based calibration approach in conceptual rainfall-runoff model calibration. Scenarios of continuous short-period observations were used to emulate poorly gauged catchments. Two approaches were employed to calibrate the HBV model for the Brue catchment in the UK. The first approach used single-objective optimization to maximize Nash–Sutcliffe efficiency (NSE) as a goodness-of-fit measure. The second approach involved multiobjective optimization based on maximizing the scores of 11 signature indices, as well as maximizing NSE. In addition, a diagnostic model evaluation approach was used to evaluate both model performance and behavioral consistency. The results showed that the HBV model was successfully calibrated using short-term datasets with a lower limit of approximately four months of data (10% FRD model). One formulation of the multiobjective signature-based optimization approach yielded the highest performance and hydrological consistency among all parameterization algorithms. The diagnostic model evaluation enabled the selection of consistent models reflecting catchment behavior and allowed an accurate detection of deficiencies in other models. It can be argued that signature-based calibration can be employed for building adequate models even in data-poor situations. Full article

(This article belongs to the Section Hydrology)

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14 pages, 29092 KiB

Open AccessEditor’s ChoiceArticle

Assessing the Effectiveness of Nourishment in Decadal Barrier Island Morphological Resilience

by Davina L. Passeri, Matthew V. Bilskie, Scott C. Hagen, Rangley C. Mickey, P. Soupy Dalyander and Victor M. Gonzalez

Water 2021, 13(7), 944; https://doi.org/10.3390/w13070944 - 30 Mar 2021

Cited by 9 | Viewed by 4480

Abstract

Nourishment has shown to be an effective method for short-term storm protection along barrier islands and sandy beaches by reducing flooding, wave attack and erosion. However, the ability of nourishment to mitigate the effects of storms and sea level rise (SLR) and improve [...] Read more.

Nourishment has shown to be an effective method for short-term storm protection along barrier islands and sandy beaches by reducing flooding, wave attack and erosion. However, the ability of nourishment to mitigate the effects of storms and sea level rise (SLR) and improve coastal resilience over decadal time scales is not well understood. This study uses integrated models of storm-driven hydrodynamics, morphodynamics and post-storm dune recovery to assess the effectiveness of beach and dune nourishment on barrier island morphological resilience over a 30-year period, accounting for storms and a moderate amount of SLR. Results show that at the end of the 30 years, nourishment contributes to maintaining island volumes by increasing barrier height and width compared with a no-action scenario (i.e., no nourishment, only natural recovery). During storms where the collision regime was dominant, higher volumes of sand were lost from the wider beach in the nourishment scenario than in the no-action scenario. During stronger storms, nourishment reduced dune overtopping compared with the no-action scenario, allowing the island to maintain height and width. Additionally, nourishment was particularly effective in reducing breaching during back-to-back storms occurring in the same year. Full article

(This article belongs to the Special Issue Advances in the Study of Coastal Resilience, Hydrodynamic Modelling and Coastal Monitoring)

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20 pages, 14643 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Water Quality and Financial Analysis of a System Combining Rainwater and Greywater in a House

by Gustavo Rosa and Enedir Ghisi

Water 2021, 13(7), 930; https://doi.org/10.3390/w13070930 - 29 Mar 2021

Cited by 9 | Viewed by 3151

Abstract

This study aimed to evaluate the installation of a system that combines rainwater to wash clothes and greywater to flush toilets in a house located in Florianópolis, southern Brazil. The evaluation consisted of determining the potable water savings, performing a financial analysis, and [...] Read more.

This study aimed to evaluate the installation of a system that combines rainwater to wash clothes and greywater to flush toilets in a house located in Florianópolis, southern Brazil. The evaluation consisted of determining the potable water savings, performing a financial analysis, and verifying the possibility of using rainwater and reusing greywater according to the local legislation. The reduction in potable water consumption was determined by comparing the monthly water and sewage bill, before and after installing the system, combining rainwater and greywater. The financial analysis was performed considering the financial benefits, operational costs, costs for installing the system, and local water tariffs. After installing the system, there was a decrease of 38.0% in the monthly potable water consumption, which represents a decrease of 7.00 m³ in the monthly potable water consumption. The payback periods for the old and new water tariffs were equivalent to, respectively, ten years and seven months, and eight years and five months. Both rainwater and greywater had parameters with concentrations higher than the limits established by the legislation. Therefore, the rainwater had to go through a device for discarding the first flush and needed disinfection; and the greywater needed to go through a treatment process. The results indicated that the system combining rainwater and greywater shows significant potential for potable water savings, which can be a good alternative to the preservation of potable water resources. It is important to note that current studies on rainwater use and greywater reuse are mainly related to non-potable purposes, but it was shown herein that rainwater can be used for washing clothes. Full article

(This article belongs to the Section Urban Water Management)

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24 pages, 4628 KiB

Open AccessEditor’s ChoiceArticle

Groundwater of the Modder River Catchment of South Africa: A Sustainability Prediction

by Saheed Adeyinka Oke and Rebecca Alowo

Water 2021, 13(7), 936; https://doi.org/10.3390/w13070936 - 29 Mar 2021

Cited by 3 | Viewed by 11827

Abstract

This paper presents a spatial interpolation of the hydrological and socioeconomic processes impacting groundwater systems to predict the sustainability of the Modder river catchment of South Africa. These processes are grouped as climatic (factor A), aquifer sustainability (factor D), social-economic and land use [...] Read more.

This paper presents a spatial interpolation of the hydrological and socioeconomic processes impacting groundwater systems to predict the sustainability of the Modder river catchment of South Africa. These processes are grouped as climatic (factor A), aquifer sustainability (factor D), social-economic and land use (factor B), and the human-induced parameters of rights and equity (factor C). The parameters evaluated for factors A and D included climatic zones, precipitation, sunshine, evapotranspiration, slope, topography, recharge, yields, storativity, aquifer types, and lithology/rock types. Factors B and C included population in the catchment, use per capita, water uses, tariffs and duration of the permits, pump rate per year, number of issued permits per year in the catchment, and number of boreholes in the sub-catchment. This paper, therefore, looks at the impact of the average values of the chosen set of parameters within the given factors A, B, C and D on groundwater in the C52 catchment of the Modder River, as modelled in a sustainability index. C52 is an Upper Orange catchment in South Africa. The results are presented in sustainability maps predicting areas in the catchment with differing groundwater dynamics. The Modder River groundwater sustainability ranged between low and moderate sustainability. The sustainability maps were validated with actual field groundwater recharge and surface water, a comparison between storativity and licensed volume, and a comparison of sustainability scores and storativity. The key finding in this paper will assist groundwater managers and users to adequately plan groundwater resources, especially on licensing and over pumping. Full article

(This article belongs to the Special Issue Geo-Environmental Approaches for the Analysis and Assessment of Groundwater Resources at Catchment-Scale)

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14 pages, 2079 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Strategies for Improving Optimal Positioning of Quality Sensors in Urban Drainage Systems for Non-Conservative Contaminants

by Mariacrocetta Sambito and Gabriele Freni

Water 2021, 13(7), 934; https://doi.org/10.3390/w13070934 - 29 Mar 2021

Cited by 43 | Viewed by 4204

Abstract

In the urban drainage sector, the problem of polluting discharges in sewers may act on the proper functioning of the sewer system, on the wastewater treatment plant reliability and on the receiving water body preservation. Therefore, the implementation of a chemical monitoring network [...] Read more.

In the urban drainage sector, the problem of polluting discharges in sewers may act on the proper functioning of the sewer system, on the wastewater treatment plant reliability and on the receiving water body preservation. Therefore, the implementation of a chemical monitoring network is necessary to promptly detect and contain the event of contamination. Sensor location is usually an optimization exercise that is based on probabilistic or black-box methods and their efficiency is usually dependent on the initial assumption made on possible eligibility of nodes to become a monitoring point. It is a common practice to establish an initial non-informative assumption by considering all network nodes to have equal possibilities to allocate a sensor. In the present study, such a common approach is compared with different initial strategies to pre-screen eligible nodes as a function of topological and hydraulic information, and non-formal ‘grey’ information on the most probable locations of the contamination source. Such strategies were previously compared for conservative xenobiotic contaminations and now they are compared for a more difficult identification exercise: the detection of nonconservative immanent contaminants. The strategies are applied to a Bayesian optimization approach that demonstrated to be efficient in contamination source location. The case study is the literature network of the Storm Water Management Model (SWMM) manual, Example 8. The results show that the pre-screening and ‘grey’ information are able to reduce the computational effort needed to obtain the optimal solution or, with equal computational effort, to improve location efficiency. The nature of the contamination is highly relevant, affecting monitoring efficiency, sensor location and computational efforts to reach optimality. Full article

(This article belongs to the Special Issue Urban Water Networks Modelling and Monitoring)

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20 pages, 2139 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Ancient WEF: Water–Energy–Food Nexus in the Distant Past

by Steven G. Pueppke

Water 2021, 13(7), 925; https://doi.org/10.3390/w13070925 - 28 Mar 2021

Cited by 13 | Viewed by 5629

Abstract

The concept of water–energy–food (WEF) nexus is gaining favor as a means to highlight the functions of the three individual nexus elements as interrelated components of a single complex system. In practice, the nexus approach projects forward from the present, seeking to maximize [...] Read more.

The concept of water–energy–food (WEF) nexus is gaining favor as a means to highlight the functions of the three individual nexus elements as interrelated components of a single complex system. In practice, the nexus approach projects forward from the present, seeking to maximize future WEF synergies and avoid undesirable tradeoffs. A complementary approach was employed here to gain insights into how the ancients dealt with WEF relationships, whether currently relevant nexus principles were practiced long ago, and how past WEF dynamics compare to those of today. Two examples, both dating to before the common era (BCE), are considered in detail. The qanats of ancient Persia brought groundwater to the surface and directed it to clusters of agricultural fields in arid areas where crop production was not otherwise feasible. In contrast, the Dujiangyan irrigation scheme of ancient China harnessed previously destructive surface water flows to stabilize food production across a vast agricultural plain. Designed and constructed under highly uncertain conditions and with a long-term perspective, both relied on local resources and expertise to exploit the tight coupling of water and the intrinsic energy from its flows to produce food. Ingenious infrastructure combined with sound governance allowed both to achieve remarkable synergies among the WEF components with minimal apparent tradeoffs. Although both are now challenged by climate change and the increasing complexity of modern WEF relationships, qanat systems and the Dujiangyan irrigation scheme have survived for millennia and still exist in recognizable form. This is due in large part to the persistence of governance systems that devolved significant decision-making authority to those who used water and energy for food production. Although it is not feasible to roll back technology to that of an earlier time, the successful attributes of earlier WEF governance systems warrant more attention in the future. Full article

(This article belongs to the Special Issue Feature Papers of Water, Agriculture and Aquaculture)

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12 pages, 3359 KiB

Open AccessEditor’s ChoiceArticle

Seasonal and Interannual Variability of EAPE in the South China Sea Derived from ECCO2 Data from 1997 to 2019

by Qiang Li, Lei Zhou and Lingling Xie

Water 2021, 13(7), 926; https://doi.org/10.3390/w13070926 - 28 Mar 2021

Cited by 2 | Viewed by 3093

Abstract

Using Estimating the Circulation and Climate of the Ocean (phase 2, ECCO2) reanalysis products from 1997 to 2019, this study analyzes the spatiotemporal features of the eddy available gravitational potential energy (EAPE) in the South China Sea (SCS). The results indicate that the [...] Read more.

Using Estimating the Circulation and Climate of the Ocean (phase 2, ECCO2) reanalysis products from 1997 to 2019, this study analyzes the spatiotemporal features of the eddy available gravitational potential energy (EAPE) in the South China Sea (SCS). The results indicate that the EAPE accounts for 64% of the total APE in the SCS with the climatological mean. The 2D EAPE distribution images manifest show high-value regions which are generally consistent with the eddy distributions. One region is located around 21° N and west of the Luzon Strait, the second around 17° N and near Luzon Island, and the third off the Vietnam coast. In the region around 21° N and 17° N, both the seasonal variability and the interannual variability associated with the El Niño–Southern Oscillation (ENSO) are significant. Off the Vietnam coast, the EAPE is closely associated with coastal processes which heavily depend on the seasonal monsoon, the El Nino/La Nina events, and the Indian Ocean Dipole (IOD). The results provide new insights into SCS dynamics from the point of view of ocean energy sources. Full article

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12 pages, 6167 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Experimental and Numerical Study of Biochar Fixed Bed Column for the Adsorption of Arsenic from Aqueous Solutions

by Maria Rosaria Boni, Simone Marzeddu, Fabio Tatti, Massimo Raboni, Giuseppe Mancini, Antonella Luciano and Paolo Viotti

Water 2021, 13(7), 915; https://doi.org/10.3390/w13070915 - 27 Mar 2021

Cited by 24 | Viewed by 4747

Abstract

Two laboratory tests were carried out to verify the suitability of an Italian commercial biochar as an adsorbing material. The chosen contaminant, considered dissolved in groundwater, was As. The circular economic concept demands the use of such waste material. Its use has been [...] Read more.

Two laboratory tests were carried out to verify the suitability of an Italian commercial biochar as an adsorbing material. The chosen contaminant, considered dissolved in groundwater, was As. The circular economic concept demands the use of such waste material. Its use has been studied in recent years on several contaminants. The possibility of using an efficient material at low cost could help the use of low-impact technologies like permeable reactive barriers (PRBs). A numerical model was used to derive the kinetic constant for two of the most used isotherms. The results are aligned with others derived from the literature, but they also indicate that the use of a large amount of biochar does not improve the efficiency of the removal. The particular origin of the biochar, together with its grain size, causes a decrease in contact time required for the adsorption. Furthermore, it is possible that a strong local decrease in the hydraulic conductibility does not allow for a correct dispersion of the flow, thereby limiting its efficiency. Full article

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14 pages, 2439 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Canadian Continental-Scale Hydrology under a Changing Climate: A Review

by Tricia A. Stadnyk and Stephen J. Déry

Water 2021, 13(7), 906; https://doi.org/10.3390/w13070906 - 26 Mar 2021

Cited by 22 | Viewed by 5953

Abstract

Canada, like other high latitude cold regions on Earth, is experiencing some of the most accelerated and intense warming resulting from global climate change. In the northern regions, Arctic amplification has resulted in warming two to three times greater than global mean temperature [...] Read more.

Canada, like other high latitude cold regions on Earth, is experiencing some of the most accelerated and intense warming resulting from global climate change. In the northern regions, Arctic amplification has resulted in warming two to three times greater than global mean temperature trends. Unprecedented warming is matched by intensification of wet and dry regions and hydroclimatic cycles, which is altering the spatial and seasonal distribution of surface waters in Canada. Diagnosing and tracking hydrologic change across Canada requires the implementation of continental-scale prediction models owing the size of Canada’s drainage basins, their distribution across multiple eco- and climatic zones, and the scarcity and paucity of observational networks. This review examines the current state of continental-scale climate change across Canada and the anticipated impacts to freshwater availability, including the role of anthropogenic regulation. The review focuses on continental and regional-scale prediction that underpins operational design and long-term resource planning and management in Canada. While there are significant process-based changes being experienced within Canadian catchments that are equally—if not more so—critical for community water availability, the focus of this review is on the cumulative effects of climate change and anthropogenic regulation for the Canadian freshwater supply. Full article

(This article belongs to the Special Issue Past and Future Trends and Variability in Hydro-Climatic Processes)

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34 pages, 2065 KiB

Open AccessEditor’s ChoiceReview

Modification of the Water Quality Index (WQI) Process for Simple Calculation Using the Multi-Criteria Decision-Making (MCDM) Method: A Review

by Naseem Akhtar, Muhammad Izzuddin Syakir Ishak, Mardiana Idayu Ahmad, Khalid Umar, Mohamad Shaiful Md Yusuff, Mohd Talha Anees, Abdul Qadir and Yazan Khalaf Ali Almanasir

Water 2021, 13(7), 905; https://doi.org/10.3390/w13070905 - 26 Mar 2021

Cited by 207 | Viewed by 25253

Abstract

Human activities continue to affect our water quality; it remains a major problem worldwide (particularly concerning freshwater and human consumption). A critical water quality index (WQI) method has been used to determine the overall water quality status of surface water and groundwater systems [...] Read more.

Human activities continue to affect our water quality; it remains a major problem worldwide (particularly concerning freshwater and human consumption). A critical water quality index (WQI) method has been used to determine the overall water quality status of surface water and groundwater systems globally since the 1960s. WQI follows four steps: parameter selection, sub-indices, establishing weights, and final index aggregation, which are addressed in this review. However, the WQI method is a prolonged process and applied to specific water quality parameters, i.e., water consumption (particular area and time) and other purposes. Therefore, this review discusses the WQI method in simple steps, for water quality assessment, based on two multi-criteria decision-making (MCDM) methods: (1) analytical hierarchical process (AHP); and (2) measuring attractiveness by a categorically based evaluation technique (MACBETH). MCDM methods can facilitate easy calculations, with less effort and great accuracy. Moreover, the uncertainty and eclipsing problems are also discussed—a challenge at every step of WQI development, particularly for parameter selection and establishing weights. This review will help provide water management authorities with useful knowledge pertaining to water usage or modification of existing indicators globally, and contribute to future WQI planning and studies for drinking, irrigation, domestic, and industrial purposes. Full article

(This article belongs to the Special Issue Assessment of Water Quality)

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11 pages, 3677 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Landfill Pollution Plume Survey in the Moroccan Tadla Using Spontaneous Potential

by Yousra El Mouine, Amal El Hamdi, Moad Morarech, Ilias Kacimi, Meryem Touzani, Ismail Mohsine, Abdessamad Tiouiouine, Jamila Ouardi, Abdelmajid Zouahri, Hasna Yachou and Houria Dakak

Water 2021, 13(7), 910; https://doi.org/10.3390/w13070910 - 26 Mar 2021

Cited by 7 | Viewed by 3859

Abstract

In many parts of the world, the impact of open landfills on soils, biosphere, and groundwater has become a major concern. These landfills frequently generate pollution plumes, the contours of which can be delineated by non-intrusive geophysical measurements, but in arid environments, the [...] Read more.

In many parts of the world, the impact of open landfills on soils, biosphere, and groundwater has become a major concern. These landfills frequently generate pollution plumes, the contours of which can be delineated by non-intrusive geophysical measurements, but in arid environments, the high soils resistivity is usually an obstacle, which results in the low number of studies that have been carried out there. In addition, such prospecting using geophysical techniques do not provide information on the intensity of the processes occurring in the water table. This study was carried out on an uncontrolled landfill in the arid Tadla plain, Morocco’s main agricultural region. A survey based on geo-referenced spontaneous potential measurements was combined with measurements of anoxic conditions (Eh-pH and O₂ equilibrating partial pressure) in the groundwater and leachates, in order to highlight a pollution plume and its geometry. The range of spontaneous potential measurement is wide, reaching 155 mV. Ponds of leachate with high electrical conductivity (20 to 40 mS cm⁻¹) form within the landfill, and present very reducing conditions down to sulphate reduction and methanisation. The plume is slowly but continuously supplied with these highly reducing and organic carbon-rich leachates from the landfill. Its direction is towards N-NW, stable throughout the season, and consistent with local knowledge of groundwater flow. The fast flow of the water table suggests pollution over long distances that should be monitored in the future. The results obtained are spatially contrasting and stable, and show that such techniques can be used on a resistive medium of arid environments. Full article

(This article belongs to the Special Issue Modeling and Prediction of Groundwater Contaminant Plumes)

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21 pages, 69677 KiB

Open AccessEditor’s ChoiceArticle

Flood Inundation Assessment in the Low-Lying River Basin Considering Extreme Rainfall Impacts and Topographic Vulnerability

by Thanh Thu Nguyen, Makoto Nakatsugawa, Tomohito J. Yamada and Tsuyoshi Hoshino

Water 2021, 13(7), 896; https://doi.org/10.3390/w13070896 - 25 Mar 2021

Cited by 10 | Viewed by 6265

Abstract

This study aims to evaluate the change in flood inundation in the Chitose River basin (CRB), a tributary of the Ishikari River, considering the extreme rainfall impacts and topographic vulnerability. The changing impacts were assessed using a large-ensemble rainfall dataset with a high [...] Read more.

This study aims to evaluate the change in flood inundation in the Chitose River basin (CRB), a tributary of the Ishikari River, considering the extreme rainfall impacts and topographic vulnerability. The changing impacts were assessed using a large-ensemble rainfall dataset with a high resolution of 5 km (d4PDF) as input data for the rainfall–runoff–inundation (RRI) model. Additionally, the prediction of time differences between the peak discharge in the Chitose River and peak water levels at the confluence point intersecting the Ishikari River were improved compared to the previous study. Results indicate that due to climatic changes, extreme river floods are expected to increase by 21–24% in the Ishikari River basin (IRB), while flood inundation is expected to be severe and higher in the CRB, with increases of 24.5, 46.5, and 13.8% for the inundation area, inundation volume, and peak inundation depth, respectively. Flood inundation is likely to occur in the CRB downstream area with a frequency of 90–100%. Additionally, the inundation duration is expected to increase by 5–10 h here. Moreover, the short time difference (0–10 h) is predicted to increase significantly in the CRB. This study provides useful information for policymakers to mitigate flood damage in vulnerable areas. Full article

(This article belongs to the Special Issue Influence of Climate Change on Floods)

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18 pages, 3104 KiB

Open AccessEditor’s ChoiceArticle

Multi-Country Scale Assessment of Available Energy Recovery Potential Using Micro-Hydropower in Drinking, Pressurised Irrigation and Wastewater Networks, Covering Part of the EU

by Djordje Mitrovic, Miguel Crespo Chacón, Aida Mérida García, Jorge García Morillo, Juan Antonio Rodríguez Diaz, Helena M. Ramos, Kemi Adeyeye, Armando Carravetta and Aonghus McNabola

Water 2021, 13(7), 899; https://doi.org/10.3390/w13070899 - 25 Mar 2021

Cited by 24 | Viewed by 4775

Abstract

Studies have shown micro-hydropower (MHP) opportunities for energy recovery and CO₂ reductions in the water sector. This paper conducts a large-scale assessment of this potential using a dataset amassed across six EU countries (Ireland, Northern Ireland, Scotland, Wales, Spain, and Portugal) for [...] Read more.

Studies have shown micro-hydropower (MHP) opportunities for energy recovery and CO₂ reductions in the water sector. This paper conducts a large-scale assessment of this potential using a dataset amassed across six EU countries (Ireland, Northern Ireland, Scotland, Wales, Spain, and Portugal) for the drinking water, irrigation, and wastewater sectors. Extrapolating the collected data, the total annual MHP potential was estimated between 482.3 and 821.6 GWh, depending on the assumptions, divided among Ireland (15.5–32.2 GWh), Scotland (17.8–139.7 GWh), Northern Ireland (5.9–8.2 GWh), Wales (10.2–8.1 GWh), Spain (375.3–539.9 GWh), and Portugal (57.6–93.5 GWh) and distributed across the drinking water (43–67%), irrigation (51–30%), and wastewater (6–3%) sectors. The findings demonstrated reductions in energy consumption in water networks between 1.7 and 13.0%. Forty-five percent of the energy estimated from the analysed sites was associated with just 3% of their number, having a power output capacity >15 kW. This demonstrated that a significant proportion of energy could be exploited at a small number of sites, with a valuable contribution to net energy efficiency gains and CO₂ emission reductions. This also demonstrates cost-effective, value-added, multi-country benefits to policy makers, establishing the case to incentivise MHP in water networks to help achieve the desired CO₂ emissions reductions targets. Full article

(This article belongs to the Special Issue Energy Recovery and Hybrid Solutions in the Water Sector)

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15 pages, 4278 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Assessment of Long-Term Fermentability of PHA-Based Materials from Pure and Mixed Microbial Cultures for Potential Environmental Applications

by Neda Amanat, Bruna Matturro, Marta Maria Rossi, Francesco Valentino, Marianna Villano and Marco Petrangeli Papini

Water 2021, 13(7), 897; https://doi.org/10.3390/w13070897 - 25 Mar 2021

Cited by 20 | Viewed by 4510

Abstract

The use of polyhydroxyalkanoates (PHA) as slow-release electron donors for environmental remediation represents a novel and appealing application that is attracting considerable attention in the scientific community. In this context, here, the fermentation pattern of different types of PHA-based materials has been investigated [...] Read more.

The use of polyhydroxyalkanoates (PHA) as slow-release electron donors for environmental remediation represents a novel and appealing application that is attracting considerable attention in the scientific community. In this context, here, the fermentation pattern of different types of PHA-based materials has been investigated in batch and continuous-flow experiments. Along with commercially available materials, produced from axenic microbial cultures, PHA produced at pilot scale by mixed microbial cultures (MMC) using waste feedstock have been also tested. As a main finding, a rapid onset of volatile fatty acids (VFA) production was observed with a low-purity MMC-deriving material, consisting of microbial cells containing 56% (on weight basis) of intracellular PHA. Indeed, with this material a sustained, long-term production of organic acids (i.e., acetic, propionic, and butyric acids) was observed. In addition, the obtained yield of conversion into acids (up to 70% gVFA/gPHA) was higher than that obtained with the other tested materials, made of extracted and purified PHA. These results clearly suggest the possibility to directly use the PHA-rich cells deriving from the MMC production process, with no need of extraction and purification procedures, as a sustainable and effective carbon source bringing remarkable advantages from an economic and environmental point of view. Full article

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

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22 pages, 7049 KiB

Open AccessEditor’s ChoiceArticle

Effect of Mean Velocity-to-Critical Velocity Ratios on Bed Topography and Incipient Motion in a Meandering Channel: Experimental Investigation

by Nargess Moghaddassi, Seyed Habib Musavi-Jahromi, Mohammad Vaghefi and Amir Khosrojerdi

Water 2021, 13(7), 883; https://doi.org/10.3390/w13070883 - 24 Mar 2021

Cited by 7 | Viewed by 3166

Abstract

As 180-degree meanders are observed in abundance in nature, a meandering channel with two consecutive 180-degree bends was designed and constructed to investigate bed topography variations. These two 180-degree mild bends are located between two upstream and downstream straight paths. In this study, [...] Read more.

As 180-degree meanders are observed in abundance in nature, a meandering channel with two consecutive 180-degree bends was designed and constructed to investigate bed topography variations. These two 180-degree mild bends are located between two upstream and downstream straight paths. In this study, different mean velocity-to-critical velocity ratios have been tested at the upstream straight path to determine the meander’s incipient motion. To this end, bed topography variations along the meander and the downstream straight path were addressed for different mean velocity-to-critical velocity ratios. In addition, the upstream bend’s effect on the downstream bend was investigated. Results indicated that the maximum scour depth at the downstream bend increased as a result of changing the mean velocity-to-critical velocity ratio from 0.8 to 0.84, 0.86, 0.89, 0.92, 0.95, and 0.98 by, respectively, 1.5, 2.5, 5, 10, 12, and 26 times. Moreover, increasing the ratio increased the maximum sedimentary height by 3, 10, 23, 48, 49, and 56 times. The upstream bend’s incipient motion was observed for the mean velocity-to-critical velocity ratio of 0.89, while the downstream bend’s incipient motion occurred for the ratio of 0.78. Full article

(This article belongs to the Section Water Erosion and Sediment Transport)

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15 pages, 3586 KiB

Open AccessEditor’s ChoiceArticle

Assessing the Risk of Legionella Infection through Showering with Untreated Rain Cistern Water in a Tropical Environment

by Hunter Quon, Maura Allaire and Sunny C. Jiang

Water 2021, 13(7), 889; https://doi.org/10.3390/w13070889 - 24 Mar 2021

Cited by 8 | Viewed by 3407

Abstract

In September 2017, two category-5 hurricanes Irma and Maria swept through the Caribbean Sea in what is now known as the region’s most active hurricane season on record, leaving disastrous effects on infrastructure and people’s lives. In the U.S. Virgin Islands, rain cisterns [...] Read more.

In September 2017, two category-5 hurricanes Irma and Maria swept through the Caribbean Sea in what is now known as the region’s most active hurricane season on record, leaving disastrous effects on infrastructure and people’s lives. In the U.S. Virgin Islands, rain cisterns are commonly used for harvesting roof-top rainwater for household water needs. High prevalence of Legionella spp. was found in the cistern water after the hurricanes. This study carried out a quantitative microbial risk assessment to estimate the health risks associated with Legionella through inhalation of aerosols from showering using water from cisterns after the hurricanes. Legionella concentrations were modeled based on the Legionella detected in post-hurricane water samples and reported total viable heterotrophic bacterial counts in cistern water. The inhalation dose was modeled using a Monte Carlo simulation of shower water aerosol concentrations according to shower water temperature, shower duration, inhalation rates, and shower flow rates. The risk of infection was calculated based on a previously established dose–response model from Legionella infection of guinea pigs. The results indicated median daily risk of 2.5 × 10⁻⁶ to 2.5 × 10⁻⁴ depending on shower temperature, and median annual risk of 9.1 × 10⁻⁴ to 1.4 × 10⁻². Results were discussed and compared with household survey results for a better understanding of local perceived risk versus objective risk surrounding local water supplies. Full article

(This article belongs to the Special Issue Water Quality and the Public Health)

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22 pages, 4138 KiB

Open AccessEditor’s ChoiceArticle

The Effect of the Effluent from a Small-Scale Conventional Wastewater Treatment Plant Treating Municipal Wastewater on the Composition and Abundance of the Microbial Community, Antibiotic Resistome, and Pathogens in the Sediment and Water of a Receiving Stream

by Kertu Tiirik, Hiie Nõlvak, Marika Truu, Angela Peeb, Margit Kõiv-Vainik and Jaak Truu

Water 2021, 13(6), 865; https://doi.org/10.3390/w13060865 - 23 Mar 2021

Cited by 8 | Viewed by 5184

Abstract

The effluents of wastewater treatment plants (WWTPs) are major contributors of nutrients, microbes—including those carrying antibiotic resistance genes (ARGs)—and pathogens to receiving waterbodies. The effect of the effluent of a small-scale activated sludge WWTP treating municipal wastewater on the composition and abundance of [...] Read more.

The effluents of wastewater treatment plants (WWTPs) are major contributors of nutrients, microbes—including those carrying antibiotic resistance genes (ARGs)—and pathogens to receiving waterbodies. The effect of the effluent of a small-scale activated sludge WWTP treating municipal wastewater on the composition and abundance of the microbial community as well as the antibiotic resistome and pathogens in the sediment and water of the receiving stream and river was studied using metagenome sequencing and a quantitative approach. Elevated Bacteroidetes proportions in the prokaryotic community, heightened sulfonamide and aminoglycoside resistance determinants proportions, and an increase of up to three orders of magnitude of sul1–sul2–aadA–blaOXA2 gene cluster abundances were recorded in stream water and sediments 0.3 km downstream of a WWTP discharge point. Further downstream, a gradual recovery of affected microbial communities along a distance gradient from WWTP was recorded, culminating in the mostly comparable state of river water and sediment parameters 3.7 km downstream of WWTP and stream water and sediments upstream of the WWTP discharge point. Archaea, especially Methanosarcina, Methanothrix, and Methanoregula, formed a substantial proportion of the microbial community of WWTP effluent as well as receiving stream water and sediment, and were linked to the spread of ARGs. Opportunistic environmental-origin pathogens were predominant in WWTP effluent and receiving stream bacterial communities, with Citrobacter freundii proportion being especially elevated in the close vicinity downstream of the WWTP discharge point. Full article

(This article belongs to the Special Issue Risk Assessment of Water Resources and Food: Microbial Contaminants, Antibiotics and Antibiotic Resistance Genes)

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15 pages, 2026 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Detecting Climate Driven Changes in Chlorophyll-a in Deep Subalpine Lakes Using Long Term Satellite Data

by Gary Free, Mariano Bresciani, Monica Pinardi, Nicola Ghirardi, Giulia Luciani, Rossana Caroni and Claudia Giardino

Water 2021, 13(6), 866; https://doi.org/10.3390/w13060866 - 23 Mar 2021

Cited by 17 | Viewed by 5034

Abstract

Climate change has increased the temperature and altered the mixing regime of high-value lakes in the subalpine region of Northern Italy. Remote sensing of chlorophyll-a can help provide a time series to allow an assessment of the ecological implications of this. Non-parametric multiplicative [...] Read more.

Climate change has increased the temperature and altered the mixing regime of high-value lakes in the subalpine region of Northern Italy. Remote sensing of chlorophyll-a can help provide a time series to allow an assessment of the ecological implications of this. Non-parametric multiplicative regression (NPMR) was used to visualize and understand the changes that have occurred between 2003–2018 in Lakes Garda, Como, Iseo, and Maggiore. In all four deep subalpine lakes, there has been a disruption from a traditional pattern of a significant spring chlorophyll-a peak followed by a clear water phase and summer/autumn peaks. This was replaced after 2010–2012, with lower spring peaks and a tendency for annual maxima to occur in summer. There was a tendency for this switch to be interspersed by a two-year period of low chlorophyll-a. Variables that were significant in NPMR included time, air temperature, total phosphorus, winter temperature, and winter values for the North Atlantic Oscillation. The change from spring to summer chlorophyll-a maxima, relatively sudden in an ecological context, could be interpreted as a regime shift. The cause was probably cascading effects from increased winter temperatures, reduced winter mixing, and altered nutrient dynamics. Future trends will depend on climate change and inter-decadal climate drivers. Full article

(This article belongs to the Special Issue Study of Lake Primary Producers and Water Quality Using Remote Sensing Techniques)

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22 pages, 10724 KiB

Open AccessEditor’s ChoiceArticle

Assessment of the Impacts of Land Use Change on Non-Point Source Loading under Future Climate Scenarios Using the SWAT Model

by Mao Feng and Zhenyao Shen

Water 2021, 13(6), 874; https://doi.org/10.3390/w13060874 - 23 Mar 2021

Cited by 18 | Viewed by 4674

Abstract

The Miyun Reservoir is an important source of surface drinking water in Beijing. Due to climate change and human activities, the inflow of Miyun Reservoir watershed (MRW) has been continuously reduced in the past 30 years, which has seriously affected the safety of [...] Read more.

The Miyun Reservoir is an important source of surface drinking water in Beijing. Due to climate change and human activities, the inflow of Miyun Reservoir watershed (MRW) has been continuously reduced in the past 30 years, which has seriously affected the safety of Beijing’s water supply. Therefore, this study aimed to assess the mitigation measures based on the quantification of the integrated impacts of climate and land use change in MRW. The non-point source (NPS) model (soil and water assessment tool, SWAT) was used for the development of future climate scenarios which were derived from two regional climate models (RCMs) under two representative concentration pathways (RCPs). Three land use scenarios were generated by the land use model (conversion of land-use and its effects (CLUE-S)): (1) historical trend scenario, (2) ecological protection without consideration of spatial configuration scenario and (3) ecological protection scenario. Moreover, the reduction of sediment and nutrients under three future land use patterns in future climate scenarios was evaluated. The results showed that an appropriate land use change project led to the desired reduction effect on sediment and nutrients output under future climate scenarios. The average reduction rates of sediment, total nitrogen and total phosphorus were 11.4%, 6.3% and 7.4%, respectively. The ecological protection scenario considering spatial configuration showed the best reduction effect on sediment, total nitrogen and total phosphorus. Therefore, the addition of region-specific preference variables as part of land use change provides better pollutant control effects. Overall, this research provides technical support to protect the safety of Beijing’s drinking water and future management of non-point source pollution in MRW. Full article

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19 pages, 4127 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Modelling Microplastics in the River Thames: Sources, Sinks and Policy Implications

by Paul G. Whitehead, Gianbattista Bussi, Jocelyne M. R. Hughes, Ana T. Castro-Castellon, Magnus D. Norling, Elizabeth S. Jeffers, Cordelia P. N. Rampley, Daniel S. Read and Alice A. Horton

Water 2021, 13(6), 861; https://doi.org/10.3390/w13060861 - 22 Mar 2021

Cited by 46 | Viewed by 11472

Abstract

With widespread, long-term historical use of plastics and the presence of microplastics in a range of new and existing products, there is rising concern about their potential impacts on freshwater ecosystems. Understanding how microplastics are transported and distributed along river systems is key [...] Read more.

With widespread, long-term historical use of plastics and the presence of microplastics in a range of new and existing products, there is rising concern about their potential impacts on freshwater ecosystems. Understanding how microplastics are transported and distributed along river systems is key to assessing impacts. Modelling the main flow dynamics, mixing, sedimentation and resuspension processes is essential for an understanding of the transport processes. We use the new, processed based, dynamic, integrated catchments (INCA) microplastics model and apply this to the whole of the freshwater catchment of the River Thames, UK, to evaluate inputs, loads and concentrations along the river system. Recent data from UK water industry studies on microplastics in effluent discharges and sewage sludge disposal has been utilised to drive the INCA microplastics model. Predicted concentrations and microplastic loads moving along the river system are shown to be significant, with a build-up of concentrations along the river, with increasing deposition on the riverbed. The potential impacts on aquatic ecosystems are evaluated and a review of policy implications is explored. Full article

(This article belongs to the Special Issue Analysis and Prevention of Microplastics Pollution in Water: Current Research and Future Directions)

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19 pages, 2522 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Water Quality and Hydrogeochemical Characteristics of Some Karst Water Sources in Apuseni Mountains, Romania

by Maria-Alexandra Hoaghia, Ana Moldovan, Eniko Kovacs, Ionut Cornel Mirea, Marius Kenesz, Traian Brad, Oana Cadar, Valer Micle, Erika Andrea Levei and Oana Teodora Moldovan

Water 2021, 13(6), 857; https://doi.org/10.3390/w13060857 - 21 Mar 2021

Cited by 24 | Viewed by 6486

Abstract

Human activities and natural factors determine the hydrogeochemical characteristics of karst groundwaters and their use as drinking water. This study assesses the hydrogeochemical characteristics of 14 karst water sources in the Apuseni Mountains (NW Romania) and their potential use as drinking water sources. [...] Read more.

Human activities and natural factors determine the hydrogeochemical characteristics of karst groundwaters and their use as drinking water. This study assesses the hydrogeochemical characteristics of 14 karst water sources in the Apuseni Mountains (NW Romania) and their potential use as drinking water sources. As shown by the Durov and by the Piper diagrams, the chemical composition of the waters is typical of karst waters as it is dominated by HCO₃⁻ and Ca²⁺, having a circumneutral to alkaline pH and total dissolved solids ranging between 131 and 1092 mg L⁻¹. The relation between the major ions revealed that dissolution is the main process contributing to the water chemistry. Limestone and dolostone are the main Ca and Mg sources, while halite is the main Na and Cl source. The Gibbs diagram confirmed the rock dominance of the water chemistry. The groundwater quality index (GWQI) showed that the waters are of excellent quality, except for two waters that displayed medium and good quality status. The quality of the studied karst waters is influenced by the geological characteristics, mainly by the water–rock interaction and, to a more limited extent, by anthropogenic activities. The investigated karst waters could be exploited as drinking water resources in the study area. The results of the present study highlight the importance of karst waters in the context of good-quality water shortage but also the vulnerability of this resource to anthropogenic influences. Full article

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

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16 pages, 2059 KiB

Open AccessEditor’s ChoiceArticle

Water-Saving Soil Conservation Measures Should Be Used in Northern China: Evidence from Runoff Plot Data

by Haiyan Fang

Water 2021, 13(6), 853; https://doi.org/10.3390/w13060853 - 20 Mar 2021

Viewed by 3166

Abstract

Most of the current studies on soil conservation measures mainly focus on their soil control effect, neglecting their impact on water quantity. In the present study, the latest seven years (2014–2020) of monitored data from 22 runoff plots in the upstream catchment of [...] Read more.

Most of the current studies on soil conservation measures mainly focus on their soil control effect, neglecting their impact on water quantity. In the present study, the latest seven years (2014–2020) of monitored data from 22 runoff plots in the upstream catchment of the Miyun Reservoir, Beijing were used to evaluate the effects of slope, rainfall, and soil conservation measures on soil and water loss, and some implications were given in this water-scarce region. Excluding the impact of soil conservation measures, soil loss increased with the slope gradient and slope length. Runoff and soil loss were greatly affected by the rainfall amount and maximum 30-min rainfall intensity on the bare and cultivated slopes, or by rainfall amount and rainfall duration on almost all of the plots with soil conservation measures. The results indicated that the bare soil suffered the most severe soil loss, with a mean annual soil loss rate (SLR) of 4325 t km⁻² year⁻¹, followed by the cultivated lands without any measure, with an annual SLR of above 3205 t km⁻² year⁻¹. Contour tillage cannot effectively control soil loss on steep slopes. The vegetation measures and terrace, level bench, and fish scale pits, as well as their combinations, can decrease runoff by above 86% and decrease soil loss by 95%, respectively. Water-saving measures should be implemented in the study region. The measures, such as vegetation coverage, terracing, contour tillage, etc., should be carefully implemented on slopes. Bare and cultivated lands should further be implemented with soil conservation measures in this and similar regions in the world. Full article

(This article belongs to the Section Hydrology)

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21 pages, 8151 KiB

Open AccessEditor’s ChoiceArticle

Integrated Technology for Evaluation and Assessment of Multi-Scale Hydrological Systems in Managing Nonpoint Source Pollution

by Henrique Momm, Ron Bingner, Robert Wells, Katy Moore and Glenn Herring

Water 2021, 13(6), 842; https://doi.org/10.3390/w13060842 - 19 Mar 2021

Cited by 5 | Viewed by 2833

Abstract

Conservation agencies need information to guide planning activities and allocation of limited mitigation resources at regional scales. Utilization of hydrological modeling tools at sub-watershed scales can adequately represent existing conditions, but information on a few discrete uncoordinated efforts cannot be scaled up to [...] Read more.

Conservation agencies need information to guide planning activities and allocation of limited mitigation resources at regional scales. Utilization of hydrological modeling tools at sub-watershed scales can adequately represent existing conditions, but information on a few discrete uncoordinated efforts cannot be scaled up to the entire region. Conversely, large scale modeling studies suffer from overgeneralization caused by needed lumping of information. In this study, a multiscale and standardized procedure was sought to characterize water and nonpoint source pollution spatiotemporal dynamics at basin-scale but through detailed field-scale analysis. The AnnAGNPS watershed pollution model was enhanced with new capabilities for simulation of large areas based on an Integrated Technology for Evaluation and Assessment of Multi-scale-hydrological Systems (ITEAMS) approach. Comparisons between the standard and proposed ITEAMS approach indicated no difference in streamflow and small underestimation of suspended sediments during high intensity rainfall events. The ITEAMS approach was applied to a basin with a total area of 3,268,691 ha which was discretized into 469,628 sub-catchments with an average size of 6.8 ha. The resulting 366 linked AnnAGNPS simulations were executed hierarchically generating estimates of water and suspended sediment yield and loads. This pilot study revealed the ITEAMS approach is a viable alternative for modeling and simulating large areas but at high spatiotemporal resolution. Full article

(This article belongs to the Special Issue Integrated Water Resource System Modeling to Support Sustainable Water Management)

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38 pages, 5145 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Rethinking Climate, Climate Change, and Their Relationship with Water

by Demetris Koutsoyiannis

Water 2021, 13(6), 849; https://doi.org/10.3390/w13060849 - 19 Mar 2021

Cited by 26 | Viewed by 25039

Abstract

We revisit the notion of climate, along with its historical evolution, tracing the origin of the modern concerns about climate. The notion (and the scientific term) of climate was established during the Greek antiquity in a geographical context and it acquired its statistical [...] Read more.

We revisit the notion of climate, along with its historical evolution, tracing the origin of the modern concerns about climate. The notion (and the scientific term) of climate was established during the Greek antiquity in a geographical context and it acquired its statistical content (average weather) in modern times after meteorological measurements had become common. Yet the modern definitions of climate are seriously affected by the wrong perception of the previous two centuries that climate should regularly be constant, unless an external agent acts upon it. Therefore, we attempt to give a more rigorous definition of climate, consistent with the modern body of stochastics. We illustrate the definition by real-world data, which also exemplify the large climatic variability. Given this variability, the term “climate change” turns out to be scientifically unjustified. Specifically, it is a pleonasm as climate, like weather, has been ever-changing. Indeed, a historical investigation reveals that the aim in using that term is not scientific but political. Within the political aims, water issues have been greatly promoted by projecting future catastrophes while reversing true roles and causality directions. For this reason, we provide arguments that water is the main element that drives climate, and not the opposite. Full article

(This article belongs to the Special Issue Climate, Water, and Soil)

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14 pages, 4004 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

A Site-Scale Tool for Performance-Based Design of Stormwater Best Management Practices

by Ali Shojaeizadeh, Mengistu Geza, Colin Bell, John McCray and Terri Hogue

Water 2021, 13(6), 844; https://doi.org/10.3390/w13060844 - 19 Mar 2021

Cited by 3 | Viewed by 3620

Abstract

The objective of this research is to develop a module for the design of best management practices based on percent pollutant removal. The module is a part of the site-scale integrated decision support tool (i-DSTss) that was developed for stormwater management. The current [...] Read more.

The objective of this research is to develop a module for the design of best management practices based on percent pollutant removal. The module is a part of the site-scale integrated decision support tool (i-DSTss) that was developed for stormwater management. The current i-DSTss tool allows for the design of best management practices based on flow reduction. The new water quality module extends the capability of the i-DSTss tool by adding new procedures for the design of best management practices based on treatment performance. The water quality module can be used to assess the treatment of colloid/total suspended solid and dissolved pollutants. We classify best management practices into storage-based (e.g., pond) and infiltration-based (e.g., bioretention and permeable pavement) practices for design purposes. Several of the more complex stormwater tools require expertise to build and operate. The i-DSTss and its component modules including the newly added water quality module are built on an accessible platform (Microsoft Excel VBA) and can be operated with a minimum skillset. Predictions from the water quality module were compared with observed data, and the goodness-of-fit was evaluated. For percent total suspended solid removal, both R² and Nash–Sutcliffe efficiency values were greater than 0.7 and 0.6 for infiltration-based and storage-based best management practices, respectively, demonstrating a good fit for both types of best management practices. For percent total phosphorous and Escherichia. coli removal, R² and Nash–Sutcliffe efficiency values demonstrated an acceptable fit. To enhance usability of the tool by a broad range of users, the tool is designed to be flexible allowing user interaction through a graphical user interface. Full article

(This article belongs to the Special Issue Cross-Sector Green Infrastructure for Improving Urban Storm Water Quality)

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18 pages, 2452 KiB

Open AccessEditor’s ChoiceArticle

From the Well to the Bottle: Identifying Sources of Microplastics in Mineral Water

by Jana Weisser, Irina Beer, Benedikt Hufnagl, Thomas Hofmann, Hans Lohninger, Natalia P. Ivleva and Karl Glas

Water 2021, 13(6), 841; https://doi.org/10.3390/w13060841 - 19 Mar 2021

Cited by 77 | Viewed by 15223

Abstract

Microplastics (MP) have been detected in bottled mineral water across the world. Because only few MP particles have been reported in ground water-sourced drinking water, it is suspected that MP enter the water during bottle cleaning and filling. However, until today, MP entry [...] Read more.

Microplastics (MP) have been detected in bottled mineral water across the world. Because only few MP particles have been reported in ground water-sourced drinking water, it is suspected that MP enter the water during bottle cleaning and filling. However, until today, MP entry paths were not revealed. For the first time, this study provides findings of MP from the well to the bottle including the bottle washing process. At four mineral water bottlers, five sample types were taken along the process: raw and deferrized water samples were filtered in situ; clean bottles were sampled right after they left the bottle washer and after filling and capping. Caustic cleaning solutions were sampled from bottle washers and MP particles isolated through enzymatic and chemical treatments. The samples were analyzed for eleven synthetic and natural polymer particles ≥11 µm with Fourier-transform infrared imaging and random decision forests. MP were present in all steps of mineral water bottling, with a sharp increase from <1 MP L⁻¹ to 317 ± 257 MP L⁻¹ attributed to bottle capping. As 81% of MP resembled the PE-based cap sealing material, abrasion from the sealings was identified as the main entry path for MP into bottled mineral water. Full article

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

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24 pages, 1779 KiB

Open AccessEditor’s ChoiceReview

The Genetic Component of Seagrass Restoration: What We Know and the Way Forwards

by Jessica Pazzaglia, Hung Manh Nguyen, Alex Santillán-Sarmiento, Miriam Ruocco, Emanuela Dattolo, Lázaro Marín-Guirao and Gabriele Procaccini

Water 2021, 13(6), 829; https://doi.org/10.3390/w13060829 - 18 Mar 2021

Cited by 45 | Viewed by 12801

Abstract

Seagrasses are marine flowering plants providing key ecological services and functions in coasts and estuaries across the globe. Increased environmental changes fueled by human activities are affecting their existence, compromising natural habitats and ecosystems’ biodiversity and functioning. In this context, restoration of disturbed [...] Read more.

Seagrasses are marine flowering plants providing key ecological services and functions in coasts and estuaries across the globe. Increased environmental changes fueled by human activities are affecting their existence, compromising natural habitats and ecosystems’ biodiversity and functioning. In this context, restoration of disturbed seagrass environments has become a worldwide priority to reverse ecosystem degradation and to recover ecosystem functionality and associated services. Despite the proven importance of genetic research to perform successful restoration projects, this aspect has often been overlooked in seagrass restoration. Here, we aimed to provide a comprehensive perspective of genetic aspects related to seagrass restoration. To this end, we first reviewed the importance of studying the genetic diversity and population structure of target seagrass populations; then, we discussed the pros and cons of different approaches used to restore and/or reinforce degraded populations. In general, the collection of genetic information and the development of connectivity maps are critical steps for any seagrass restoration activity. Traditionally, the selection of donor population preferred the use of local gene pools, thought to be the best adapted to current conditions. However, in the face of rapid ocean changes, alternative approaches such as the use of climate-adjusted or admixture genotypes might provide more sustainable options to secure the survival of restored meadows. Also, we discussed different transplantation strategies applied in seagrasses and emphasized the importance of long-term seagrass monitoring in restoration. The newly developed information on epigenetics as well as the application of assisted evolution strategies were also explored. Finally, a view of legal and ethical issues related to national and international restoration management is included, highlighting improvements and potential new directions to integrate with the genetic assessment. We concluded that a good restoration effort should incorporate: (1) a good understanding of the genetic structure of both donors and populations being restored; (2) the analysis of local environmental conditions and disturbances that affect the site to be restored; (3) the analysis of local adaptation constraints influencing the performances of donor populations and native plants; (4) the integration of distribution/connectivity maps with genetic information and environmental factors relative to the target seagrass populations; (5) the planning of long-term monitoring programs to assess the performance of the restored populations. The inclusion of epigenetic knowledge and the development of assisted evolution programs are strongly hoped for the future. Full article

(This article belongs to the Special Issue Restore Degraded Marine Coastal Areas in the Mediterranean Sea)

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17 pages, 3441 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Improving Mean Annual Precipitation Prediction Incorporating Elevation and Taking into Account Support Size

by Gabriele Buttafuoco and Massimo Conforti

Water 2021, 13(6), 830; https://doi.org/10.3390/w13060830 - 18 Mar 2021

Cited by 8 | Viewed by 3118

Abstract

Accounting for secondary exhaustive variables (such as elevation) in modelling the spatial distribution of precipitation can improve their estimate accuracy. However, elevation and precipitation data are associated with different support sizes and it is necessary to define methods to combine such different spatial [...] Read more.

Accounting for secondary exhaustive variables (such as elevation) in modelling the spatial distribution of precipitation can improve their estimate accuracy. However, elevation and precipitation data are associated with different support sizes and it is necessary to define methods to combine such different spatial data. The paper was aimed to compare block ordinary cokriging and block kriging with an external drift in estimating the annual precipitation using elevation as covariate. Block ordinary kriging was used as reference of a univariate geostatistical approach. In addition, the different support sizes associated with precipitation and elevation data were also taken into account. The study area was the Calabria region (southern Italy), which has a spatially variable Mediterranean climate because of its high orographic variability. Block kriging with elevation as external drift, compared to block ordinary kriging and block ordinary cokriging, was the most accurate approach for modelling the spatial distribution of annual mean precipitation. The three measures of accuracy (MAE, mean absolute error; RMSEP, root-mean-squared error of prediction; MRE, mean relative error) have the lowest values (MAE = 112.80 mm; RMSEP = 144.89 mm, and MRE = 0.11), whereas the goodness of prediction (G) has the highest value (75.67). The results clearly indicated that the use of an exhaustive secondary variable always improves the precipitation estimate, but in the case of areas with elevations below 120 m, block cokriging makes better use of secondary information in precipitation estimation than block kriging with external drift. At higher elevations, the opposite is always true: block kriging with external drift performs better than block cokriging. This approach takes into account the support size associated with precipitation and elevation data. Accounting for elevation allowed to obtain more detailed maps than using block ordinary kriging. However, block kriging with external drift produced a map with more local details than that of block ordinary cokriging because of the local re-evaluation of the linear regression of precipitation on block estimates. Full article

(This article belongs to the Special Issue Modelling Precipitation in Space and Time)

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15 pages, 3124 KiB

Open AccessEditor’s ChoiceArticle

Reservoir Sediment Management Using Artificial Neural Networks: A Case Study of the Lower Section of the Alpine Saalach River

by Markus Reisenbüchler, Minh Duc Bui and Peter Rutschmann

Water 2021, 13(6), 818; https://doi.org/10.3390/w13060818 - 16 Mar 2021

Cited by 22 | Viewed by 3686

Abstract

Reservoir sedimentation is a critical issue worldwide, resulting in reduced storage volumes and, thus, reservoir efficiency. Moreover, sedimentation can also increase the flood risk at related facilities. In some cases, drawdown flushing of the reservoir is an appropriate management tool. However, there are [...] Read more.

Reservoir sedimentation is a critical issue worldwide, resulting in reduced storage volumes and, thus, reservoir efficiency. Moreover, sedimentation can also increase the flood risk at related facilities. In some cases, drawdown flushing of the reservoir is an appropriate management tool. However, there are various options as to how and when to perform such flushing, which should be optimized in order to maximize its efficiency and effectiveness. This paper proposes an innovative concept, based on an artificial neural network (ANN), to predict the volume of sediment flushed from the reservoir given distinct input parameters. The results obtained from a real-world study area indicate that there is a close correlation between the inputs—including peak discharge and duration of flushing—and the output (i.e., the volume of sediment). The developed ANN can readily be applied at the real-world study site, as a decision-support system for hydropower operators. Full article

(This article belongs to the Special Issue Sediment Transport and River Morphology)

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26 pages, 32717 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

The “Problem” of New Orleans and Diminishing Sustainability of Mississippi River Management—Future Options

by John W. Day, Rachael Hunter, G. Paul Kemp, Matthew Moerschbaecher and Christopher G. Brantley

Water 2021, 13(6), 813; https://doi.org/10.3390/w13060813 - 16 Mar 2021

Cited by 5 | Viewed by 10363

Abstract

Climate change forcings are having significant impacts in coastal Louisiana today and increasingly affect the future of New Orleans, a deltaic city mostly below sea level, which depends on levee and pumps to protect from a host of water-related threats. Precipitation has increased [...] Read more.

Climate change forcings are having significant impacts in coastal Louisiana today and increasingly affect the future of New Orleans, a deltaic city mostly below sea level, which depends on levee and pumps to protect from a host of water-related threats. Precipitation has increased in the Mississippi River basin generally, increasing runoff, so that in recent years the Mississippi River has been above flood stage for longer periods of time both earlier and later in the year, increasing the likelihood that hurricane surge, traditionally confined to summer and fall, may compound effects of prolonged high water on river levees. The Bonnet Carré Spillway, just upstream of New Orleans has been operated more often and for longer periods of time in recent years than ever before in its nearly 100-year history. Because all rain that falls within the city must be pumped out, residents have been exposed to interior flooding more frequently as high-intensity precipitation events can occur in any season. A sustainable path for New Orleans should involve elevating people and sensitive infrastructure above flood levels, raising some land levels, and creating water storage areas within the city. Management of the lower Mississippi River in the future must include consideration that the river will exceed its design capacity on a regular basis. The river must also be used to restore coastal wetlands through the use of diversions, which will also relieve pressure on levees. Full article

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

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18 pages, 3674 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Improving Spatial Landslide Prediction with 3D Slope Stability Analysis and Genetic Algorithm Optimization: Application to the Oltrepò Pavese

by Nunziarita Palazzolo, David J. Peres, Massimiliano Bordoni, Claudia Meisina, Enrico Creaco and Antonino Cancelliere

Water 2021, 13(6), 801; https://doi.org/10.3390/w13060801 - 15 Mar 2021

Cited by 34 | Viewed by 5859

Abstract

In this study, we compare infinite slope and the three-dimensional stability analysis performed by SCOOPS 3D (software to analyze three-dimensional slope stability throughout a digital landscape). SCOOPS 3D is a model proposed by the U. S. Geological Survey (USGS), the potentialities of which [...] Read more.

In this study, we compare infinite slope and the three-dimensional stability analysis performed by SCOOPS 3D (software to analyze three-dimensional slope stability throughout a digital landscape). SCOOPS 3D is a model proposed by the U. S. Geological Survey (USGS), the potentialities of which have still not been investigated sufficiently. The comparison between infinite slope and 3D slope stability analysis is carried out using the same hydrological analysis, which is performed with TRIGRS (transient rainfall infiltration and grid-based regional slope-stability model)—another model proposed by USGS. The SCOOPS 3D model requires definition of a series of numerical parameters that can have a significant impact on its own performance, for a given set of physical properties. In the study, we calibrate these numerical parameters through a multi-objective optimization based on genetic algorithms to maximize the model predictability performance in terms of statistics of the receiver operating characteristics (ROC) confusion matrix. This comparison is carried out through an application on a real case study, a catchment in the Oltrepò Pavese (Italy), in which the areas of triggered landslides were accurately monitored during an extreme rainfall on 27–28 April 2009. Results show that the SCOOPS 3D model performs better than the 1D infinite slope stability analysis, as the ROC True Skill Statistic increases from 0.09 to 0.37. In comparison to other studies, we find the 1D model performs worse, likely for the availability of less detailed geological data. On the other side, for the 3D model we find even better results than the two other studies present to date in the scientific literature. This is to be attributed to the optimization process we proposed, which allows to have a greater gain of performance passing from the 1D to the 3D simulation, in comparison to the above-mentioned studies, where no optimization has been applied. Thus, our study contributes to improving the performances of landslide models, which still remain subject to many uncertainty factors. Full article

(This article belongs to the Special Issue Hydrological Modeling Research for Rainfall-Induced Landslides)

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25 pages, 9782 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Is It a Drought or Only a Fluctuation in Precipitation Patterns?—Drought Reconnaissance in Poland

by Emilia Karamuz, Ewa Bogdanowicz, Tesfaye Belay Senbeta, Jarosław Jan Napiórkowski and Renata Julita Romanowicz

Water 2021, 13(6), 807; https://doi.org/10.3390/w13060807 - 15 Mar 2021

Cited by 23 | Viewed by 4008

Abstract

The process of propagation from meteorological to hydrological drought is studied using the Vistula basin in Poland (193,960 km²) as a case study. The study aims to set a background for the analysis of processes influencing drought propagation in the basin, [...] Read more.

The process of propagation from meteorological to hydrological drought is studied using the Vistula basin in Poland (193,960 km²) as a case study. The study aims to set a background for the analysis of processes influencing drought propagation in the basin, including the availability of data on hydro-meteorological factors, groundwater, and major human activities that might influence the water cycle in the region. A recent history of drought events in the basin is derived based on a statistical analysis of flow measured at nine gauging stations located along the river, starting from upstream downwards in the 1951–2018 period. The study is enhanced by the analysis of the temporal and spatial variability of a number of drought indices. As a result, the factors affecting temporal and spatial variability of drought—with particular emphasis on the interaction between the variability induced by natural processes and human interaction—are identified. The drought dynamics is studied by analysis of the relationships between meteorological and hydrological drought indices. The results indicate that the Vistula River basin has been influenced in its upstream part mainly by the mining industry, and the middle and downstream parts are additionally affected by industry and agriculture. Full article

(This article belongs to the Special Issue Human and Climate Impacts on Drought Dynamics and Vulnerability)

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20 pages, 4267 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Future Flood Hazard Assessment for the City of Pamplona (Spain) Using an Ensemble of Climate Change Projections

by Marco Lompi, Luis Mediero and Enrica Caporali

Water 2021, 13(6), 792; https://doi.org/10.3390/w13060792 - 14 Mar 2021

Cited by 11 | Viewed by 3763

Abstract

Understanding how the design hyetographs and floods will change in the future is essential for decision making in flood management plans. This study provides a methodology to quantify the expected changes in future hydraulic risks at the catchment scale in the city of [...] Read more.

Understanding how the design hyetographs and floods will change in the future is essential for decision making in flood management plans. This study provides a methodology to quantify the expected changes in future hydraulic risks at the catchment scale in the city of Pamplona. It considers climate change projections supplied by 12 climate models, 7 return periods, 2 emission scenarios (representative concentration pathway RCP 4.5 and RCP 8.5), and 3 time windows (2011–2040, 2041–2070, and 2070–2100). The Real-time Interactive Basin Simulator (RIBS) distributed hydrological model is used to simulate rainfall-runoff processes at the catchment scale. The results point to a decrease in design peak discharges for return periods smaller than 10 years and an increase for the 500- and 1000-year floods for both RCPs in the three time windows. The emission scenario RCP 8.5 usually provides the greatest increases in flood quantiles. The increase of design peak discharges is almost 10–30% higher in RCP 8.5 than in RCP 4.5. Change magnitudes for the most extreme events seem to be related to the greenhouse gas emission predictions in each RCP, as the greatest expected changes are found in 2040 for the RCP 4.5 and in 2100 for the RCP 8.5. Full article

(This article belongs to the Special Issue Influence of Climate Change on Floods)

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16 pages, 1713 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Methods in Capturing the Spatiotemporal Dynamics of Flow and Biogeochemical Reactivity in Sandy Beach Aquifers: A Review

by Kyra H. Kim and James W. Heiss

Water 2021, 13(6), 782; https://doi.org/10.3390/w13060782 - 13 Mar 2021

Cited by 17 | Viewed by 4626

Abstract

Sandy beach aquifers are complex hydrological and biogeochemical systems where fresh groundwater and seawater mix. The extent of the intertidal mixing zone and the rates of circulating flows within beaches are a primary control on porewater chemistry and microbiology of the intertidal subsurface. [...] Read more.

Sandy beach aquifers are complex hydrological and biogeochemical systems where fresh groundwater and seawater mix. The extent of the intertidal mixing zone and the rates of circulating flows within beaches are a primary control on porewater chemistry and microbiology of the intertidal subsurface. Interplay between the hydrological and biogeochemical processes at these land-sea transition zones moderate fluxes of chemicals, particulates, heavy metals, and biota across the aquifer-ocean interface, affecting coastal water quality and nutrient loads to marine ecosystems. Thus, it is important to characterize hydrological and biogeochemical processes in beach aquifers when estimating material fluxes to the ocean. This can be achieved through a suite of cross-disciplinary measurements of beach groundwater flow and chemistry. In this review, we present measurement approaches that have been developed and employed to characterize the physical (geology, topography, subsurface hydrology) and biogeochemical (solute and particulate distributions, reaction rates) properties of and processes occurring within sandy intertidal aquifers. As applied to beach systems, we discuss vibracoring, sample collection, laboratory experiments, variable-density considerations, instrument construction, and sensor technologies. We discuss advantages and limitations of typical hydrologic field sampling methods when used to investigate beach aquifers and provide a measurement framework for researchers seeking to sample and collect data from these systems. Full article

(This article belongs to the Special Issue Advances in the Study and Understanding of Groundwater Discharge to Surface Water)

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12 pages, 2251 KiB

Open AccessEditor’s ChoiceArticle

Coastal Erosion of Arctic Cultural Heritage in Danger: A Case Study from Svalbard, Norway

by Ionut Cristi Nicu, Lena Rubensdotter, Knut Stalsberg and Erich Nau

Water 2021, 13(6), 784; https://doi.org/10.3390/w13060784 - 13 Mar 2021

Cited by 31 | Viewed by 5505

Abstract

Strong cultural heritage management relies on a thorough evaluation of the threats faced by heritage sites, both in the present and in the future. In this study, we analysed the changes in the position of Hiorthhamn shoreline (Svalbard), which is affecting coastal cultural [...] Read more.

Strong cultural heritage management relies on a thorough evaluation of the threats faced by heritage sites, both in the present and in the future. In this study, we analysed the changes in the position of Hiorthhamn shoreline (Svalbard), which is affecting coastal cultural heritage sites, for a period of 93 years (1927–2020). Shoreline changes were mapped by using maps, ortophotos, drone images, terrestrial laser scanning (TLS), and topographic surveys. Also, TLS was used to 3D document the endangered coastal cultural heritage sites. Detailed sedimentological and morphological mapping was made in the field and from the newly acquired drone images in order to understand shoreline-landscape interaction and to depict changes occurring from 2019 to 2020. Short-term (2019–2020) and long-term (1927–2020) shoreline erosion/accretion was made with the help of the Digital Shoreline Analysis System (DSAS) and prompted a subdivision of three sectors, based on change pattern. Compared to a previous long-term analysis (1927–2019), this year’s average erosion rate analysis (expressed by the EPR parameter) for the 93-year period is −0.14 m/yr. This shift in mean development is due to a newly formed spit-bar in Sector 2. Referring strictly to Sector 1, where the protected cultural heritage objects are located, the erosion rate increased from the previous analysis of –0.76 m/yr to −0.77 m/yr. The shoreline forecast analysis highlights that half of the protected cultural heritage objects will likely disappear over the next decade and almost all the cultural heritage objects analysed in this study will disappear in roughly two decades. This shows the great danger the Arctic’s cultural heritage sites is in if no mitigation measures are undertaken by the local authorities. Full article

(This article belongs to the Special Issue Hydrology of the Arctic Region)

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27 pages, 2563 KiB

Open AccessEditor’s ChoiceReview

Review of Seawater Intrusion in Western Coastal Regions of South Korea

by Sung-Wook Jeen, Jiyoung Kang, Hyejung Jung and Jeonghoon Lee

Water 2021, 13(6), 761; https://doi.org/10.3390/w13060761 - 11 Mar 2021

Cited by 41 | Viewed by 6578

Abstract

Groundwater salinization in coastal aquifers because of seawater intrusion has raised serious concerns worldwide since it deteriorates the quality of drinking water and thereby threatens sustainable economic development. In particular, this problem has been a cause of growing concern in the western coastal [...] Read more.

Groundwater salinization in coastal aquifers because of seawater intrusion has raised serious concerns worldwide since it deteriorates the quality of drinking water and thereby threatens sustainable economic development. In particular, this problem has been a cause of growing concern in the western coastal regions of South Korea. In this paper, we review studies of seawater intrusion in western coastal regions of South Korea conducted over the past 20 years, particularly focusing on studies reported in international journals. We summarize the study locations, methods used, and major findings from individual and regional-scale studies. General methods used to identify and interpret seawater intrusion and subsequent geochemical processes are also presented. On the basis of insights gleaned from the previous studies, future research needs are discussed. Full article

(This article belongs to the Special Issue Seawater Intrusion into Coastal Aquifers)

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24 pages, 11291 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Hydrogeochemical and Hydrodynamic Assessment of Tirnavos Basin, Central Greece

by Ioannis Vrouhakis, Evangelos Tziritis, Andreas Panagopoulos and Georgios Stamatis

Water 2021, 13(6), 759; https://doi.org/10.3390/w13060759 - 11 Mar 2021

Cited by 5 | Viewed by 3817

Abstract

A combined hydrogeochemical and hydrodynamic characterization for the assessment of key aspects related to groundwater resources management was performed in a highly productive agricultural basin of the Thessaly region in central Greece. A complementary suite of tools and methods—including graphical processing, hydrogeochemical modeling, [...] Read more.

A combined hydrogeochemical and hydrodynamic characterization for the assessment of key aspects related to groundwater resources management was performed in a highly productive agricultural basin of the Thessaly region in central Greece. A complementary suite of tools and methods—including graphical processing, hydrogeochemical modeling, multivariate statistics and environmental isotopes—have been applied to a comprehensive dataset of physicochemical analyses and water level measurements. Results revealed that the initial hydrogeochemistry of groundwater was progressively impacted by secondary phenomena (e.g., ion exchange and redox reactions) which were clearly delineated into distinct zones according to data processing. The progressive evolution of groundwater was further verified by the variation of the saturation indices of critical minerals. In addition, the combined use of water level measurements delineated the major pathways of groundwater flow. Interestingly, the additional joint assessment of environmental isotopes revealed a new pathway from E–NE (which had never before been validated), thus highlighting the importance of the joint tools/methods application in complex scientific tasks. The application of multivariate statistics identified the dominant processes that control hydrogeochemistry and fit well with identified hydrodynamic mechanisms. These included (as dominant factor) the salinization impact due to the combined use of irrigation water return and evaporitic mineral leaching, as well as the impact of the geogenic calcareous substrate (mainly karstic calcareous formations and dolostones). Secondary factors, acting as processes (e.g., redox and ion exchange), were identified and found to be in line with initial assessment, thus validating the overall characterization. Finally, the outcomes may prove to be valuable in the progression toward sustainable groundwater resources management. The results have provided spatial and temporal information for significant parameters, sources, and processes—which, as a methodological approach, could be adopted in similar cases of other catchments. Full article

(This article belongs to the Special Issue Geo-Environmental Approaches for the Analysis and Assessment of Groundwater Resources at Catchment-Scale)

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15 pages, 2385 KiB

Open AccessEditor’s ChoiceArticle

Nonstationary Analyses of the Maximum and Minimum Streamflow in Tamsui River Basin, Taiwan

by Jenq-Tzong Shiau and Yi-Ting Liu

Water 2021, 13(6), 762; https://doi.org/10.3390/w13060762 - 11 Mar 2021

Cited by 2 | Viewed by 2716

Abstract

This study aims to detect non-stationarity of the maximum and minimum streamflow regime in Tamsui River basin, northern Taiwan. Seven streamflow gauge stations, with at least 27-year daily records, are used to characterize annual maximum 1- and 2-day flows and annual minimum 1-, [...] Read more.

This study aims to detect non-stationarity of the maximum and minimum streamflow regime in Tamsui River basin, northern Taiwan. Seven streamflow gauge stations, with at least 27-year daily records, are used to characterize annual maximum 1- and 2-day flows and annual minimum 1-, 7-, and 30-day flows. The generalized additive models for location, scale, and shape (GAMLSS) are used to dynamically detect evolution of probability distributions of the maximum and minimum flow indices with time. Results of time-covariate models indicate that stationarity is only noted in the 4 maximum flow indices out of 35 indices. This phenomenon indicates that the minimum flow indices are vulnerable to changing environments. A 16-category distributional-change scheme is employed to classify distributional changes of flow indices. A probabilistic distribution with complex variations of mean and variance is prevalent in the Tamsui River basin since approximate one third of flow indices (34.3%) belong to this category. To evaluate impacts of dams on streamflow regime, a dimensionless index called the reservoir index (RI) serves as an alternative covariate to model nonstationary probability distribution. Results of RI-covariate models indicate that 7 out of 15 flow indices are independent of RI and 80% of the best-fitted RI-covariate models are generally worse than the time-covariate models. This fact reveals that the dam is not the only factor in altering the streamflow regime in the Tamsui River, which is a significant alteration, especially the minimum flow indices. The obtained distributional changes of flow indices clearly indicate changes in probability distributions with time. Non-stationarity in the Tamsui River is induced by climate change and complex anthropogenic interferences. Full article

(This article belongs to the Section Hydrology)

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16 pages, 1618 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Design of a MATLAB HEC-RAS Interface to Test Advanced Control Strategies on Water Systems

by Ronan Deshays, Pablo Segovia and Eric Duviella

Water 2021, 13(6), 763; https://doi.org/10.3390/w13060763 - 11 Mar 2021

Cited by 6 | Viewed by 6247

Abstract

The software package HEC-RAS (Hydrologic Engineering Center’s River Analysis System) is widely used by the water engineering community to analyze hydraulic systems and perform development planning. Furthermore, it integrates a control module that allows implementing basic controllers. For more complex approaches, developers from [...] Read more.

The software package HEC-RAS (Hydrologic Engineering Center’s River Analysis System) is widely used by the water engineering community to analyze hydraulic systems and perform development planning. Furthermore, it integrates a control module that allows implementing basic controllers. For more complex approaches, developers from the automatic control and artificial intelligence (AI) communities usually design, implement, and test new algorithms using dedicated software such as MATLAB. However, models of hydraulic systems employed in MATLAB are often very simple. The main objective of the paper is to design a simulation architecture by coupling HEC-RAS with MATLAB, thus improving the accuracy of the dynamics of the hydraulic systems considered in the control simulations. The main feature of the MATLAB HEC-RAS interface design is that it allows one to execute customized code at regular time intervals during the simulation. In this way, closed-loop control and optimization algorithms can be implemented and tested. Moreover, the generic interface allows for any configuration of hydrographical systems. The proposed interface is presented in this paper, and the performance of the approach is demonstrated considering two case studies of different nature. Full article

(This article belongs to the Special Issue Smart Water Management and Flood Mitigation)

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32 pages, 3654 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Optimization of Vineyard Water Management: Challenges, Strategies, and Perspectives

by José Manuel Mirás-Avalos and Emily Silva Araujo

Water 2021, 13(6), 746; https://doi.org/10.3390/w13060746 - 10 Mar 2021

Cited by 84 | Viewed by 14519

Abstract

Water availability is endangering the production, quality, and economic viability of growing wine grapes worldwide. Climate change projections reveal warming and drying trends for the upcoming decades, constraining the sustainability of viticulture. In this context, a great research effort over the last years [...] Read more.

Water availability is endangering the production, quality, and economic viability of growing wine grapes worldwide. Climate change projections reveal warming and drying trends for the upcoming decades, constraining the sustainability of viticulture. In this context, a great research effort over the last years has been devoted to understanding the effects of water stress on grapevine performance. Moreover, irrigation scheduling and other management practices have been tested in order to alleviate the deleterious effects of water stress on wine production. The current manuscript provides a comprehensive overview of the advances in the research on optimizing water management in vineyards, including the use of novel technologies (modeling, remote sensing). In addition, methods for assessing vine water status are summarized. Moreover, the manuscript will focus on the interactions between grapevine water status and biotic stressors. Finally, future perspectives for research are provided. These include the performance of multifactorial studies accounting for the interrelations between water availability and other stressors, the development of a cost-effective and easy-to-use tool for assessing vine water status, and the study of less-known cultivars under different soil and climate conditions. Full article

(This article belongs to the Special Issue Water Management in Woody Crops: Challenges and Opportunities)

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15 pages, 1925 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Water Quality and Life Expectancy: Parallel Courses in Time

by Andreas N. Angelakis, Heikki S. Vuorinen, Christos Nikolaidis, Petri S. Juuti, Tapio S. Katko, Riikka P. Juuti, Jim Zhang and George Samonis

Water 2021, 13(6), 752; https://doi.org/10.3390/w13060752 - 10 Mar 2021

Cited by 22 | Viewed by 18565

Abstract

Since ancient times, the need for healthy water has resulted in the development of various kinds of water supply systems. From early history, civilizations have developed water purification devices and treatment methods. The necessity for fresh water has influenced individual lives as well [...] Read more.

Since ancient times, the need for healthy water has resulted in the development of various kinds of water supply systems. From early history, civilizations have developed water purification devices and treatment methods. The necessity for fresh water has influenced individual lives as well as communities and societies. During the last two hundred years, intensive and effective efforts have been made internationally for sufficient water quantity and quality. At the same time, human life expectancy has increased all over the globe at unprecedented rates. The present work represents an effort to sketch out how water purity and life expectancy have entangled, thus influencing one another. Water properties and characteristics have directly affected life quality and longevity. The dramatic increase in life expectancy has been, indisputably, affected by the improvement in water quality, but also in other concomitant factors, varying temporally and spatially in different parts of the world throughout the centuries. Water technologies and engineering have an unequivocal role on life expectancy. In some cases, they appear to have taken place earlier than the progress of modern medicine. Among these, improved sanitation, personal hygiene, progress in medicine, and better standards of economic living have played the greatest roles. Full article

(This article belongs to the Special Issue Water Scarcity: From Ancient to Modern Times and the Future)

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25 pages, 10113 KiB

Open AccessEditor’s ChoiceArticle

Means and Extremes: Evaluation of a CMIP6 Multi-Model Ensemble in Reproducing Historical Climate Characteristics across Alberta, Canada

by Badrul Masud, Quan Cui, Mohamed E. Ammar, Barrie R. Bonsal, Zahidul Islam and Monireh Faramarzi

Water 2021, 13(5), 737; https://doi.org/10.3390/w13050737 - 9 Mar 2021

Cited by 29 | Viewed by 5880

Abstract

This study evaluates General Circulation Models (GCMs) participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6) for their ability in simulating historical means and extremes of daily precipitation (P), and daily maximum (Tmax), and minimum temperature (Tmin). Models are evaluated against hybrid [...] Read more.

This study evaluates General Circulation Models (GCMs) participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6) for their ability in simulating historical means and extremes of daily precipitation (P), and daily maximum (Tmax), and minimum temperature (Tmin). Models are evaluated against hybrid observations at 2255 sub-basins across Alberta, Canada using established statistical metrics for the 1983–2014 period. Three extreme indices including consecutive wet days (CWD), summer days (SD), and warm nights (WN) are defined based on the peak over the threshold approach and characterized by duration and frequency. The tail behaviour of extremes is evaluated using the Generalized Pareto Distribution. Regional evaluations are also conducted for four climate sub-regions across the study area. For both mean annual precipitation and mean annual daily temperature, most GCMs more accurately reproduce the observations in northern Alberta and follow a gradient toward the south having the poorest representation in the western mountainous area. Model simulations show statistically better performance in reproducing mean annual daily Tmax than Tmin, and in reproducing annual mean duration compared to the frequency of extreme indices across the province. The Kernel density curves of duration and frequency as simulated by GCMs show closer agreement to that of observations in the case of CWD. However, it is slightly (completely) overestimated (underestimated) by GCMs for warm nights (summer days). The tail behaviour of extremes indicates that GCMs may not incorporate some local processes such as the convective parameterization scheme in the simulation of daily precipitation. Model performances in each of the four sub-regions are quite similar to their performances at the provincial scale. Bias-corrected and downscaled GCM simulations using a hybrid approach show that the downscaled GCM simulations better represent the means and extremes of P characteristics compared to Tmax and Tmin. There is no clear indication of an improved tail behaviour of GPD based on downscaled simulations. Full article

(This article belongs to the Special Issue Past and Future Trends and Variability in Hydro-Climatic Processes)

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32 pages, 30439 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Quaternary Evolution of the Lower Calore and Middle Volturno Valleys (Southern Italy)

by Francesca Filocamo, Natalia Leone, Carmen Maria Rosskopf, Vittoria Scorpio, Santiago Giralt and Pietro Patrizio Ciro Aucelli

Water 2021, 13(5), 741; https://doi.org/10.3390/w13050741 - 9 Mar 2021

Cited by 4 | Viewed by 3786

Abstract

The lower Calore and middle Volturno valleys preserve stratigraphical and morphological evidence and tephrostratigraphic markers particularly suitable for reconstructing the long-term geomorphological evolution of the central-southern Apennines. Aim of our study is to identify the main steps of the Quaternary landscape evolution of [...] Read more.

The lower Calore and middle Volturno valleys preserve stratigraphical and morphological evidence and tephrostratigraphic markers particularly suitable for reconstructing the long-term geomorphological evolution of the central-southern Apennines. Aim of our study is to identify the main steps of the Quaternary landscape evolution of these valley systems and to improve knowledge about the relationships between fluvial processes and tectonics, volcanic activity, climatic and human influences. To this purpose, we carried out an integrated geomorphological and chrono-stratigraphical analysis of identified fluvial landforms and related deposits, integrated by ²³⁰Th/²³⁴U datings on travertines from the Telese Plain area. The study highlighted in particular: (1) fluvial sedimentation started in the Middle Pleistocene (~650 ka) within valleys that originated in the lower Pleistocene under the control of high-angle faults; (2) extensional tectonics acted during the Middle and Upper Pleistocene, driving the formation of the oldest fluvial terraces and alluvial fans, and persisted beyond the emplacement of the Campanian Ignimbrite pyroclastic deposits (~39 ka); and (3) from the late Upper Pleistocene onwards (<15 ka), the role of tectonics appears negligible, while climatic changes played a key role in the formation of three orders of valley floor terraces and the youngest alluvial fans. Full article

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

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23 pages, 2282 KiB

Open AccessEditor’s ChoiceArticle

Natural Background Levels of Potentially Toxic Elements in Groundwater from a Former Asbestos Mine in Serpentinite (Balangero, North Italy)

by Elisa Sacchi, Massimo Bergamini, Elisa Lazzari, Arianna Musacchio, Jordi-René Mor and Elisa Pugliaro

Water 2021, 13(5), 735; https://doi.org/10.3390/w13050735 - 8 Mar 2021

Cited by 16 | Viewed by 3166

Abstract

The definition of natural background levels (NBLs) for potentially toxic elements (PTEs) in groundwater from mining environments is a real challenge, as anthropogenic activities boost water–rock interactions, further increasing the naturally high concentrations. This study illustrates the procedure followed to derive PTE concentration [...] Read more.

The definition of natural background levels (NBLs) for potentially toxic elements (PTEs) in groundwater from mining environments is a real challenge, as anthropogenic activities boost water–rock interactions, further increasing the naturally high concentrations. This study illustrates the procedure followed to derive PTE concentration values that can be adopted as NBLs for the former Balangero asbestos mine, a “Contaminated Site of National Interest”. A full hydrogeochemical characterisation allowed for defining the dominant Mg-HCO₃ facies, tending towards the Mg-SO₄ facies with increasing mineralisation. PTE concentrations are high, and often exceed the groundwater quality thresholds for Cr VI, Ni, Mn and Fe (5, 20, 50 and 200 µg/L, respectively). The Italian guidelines for NBL assessment recommend using the median as a representative concentration for each monitoring station. However, this involves discarding half of the measurements and in particular the higher concentrations, thus resulting in too conservative estimates. Using instead all the available measurements and the recommended statistical evaluation, the derived NBLs were: Cr = 39.3, Cr VI = 38.1, Ni = 84, Mn = 71.36, Fe = 58.4, Zn = 232.2 µg/L. These values are compared to literature data from similar hydrogeochemical settings, to support the conclusion on their natural origin. Results highlight the need for a partial rethink of the guidelines for the assessment of NBLs in naturally enriched environmental settings. Full article

(This article belongs to the Special Issue Natural Background Levels in Groundwater)

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17 pages, 9236 KiB

Open AccessEditor’s ChoiceArticle

Stratigraphic Analysis of Firn Cores from an Antarctic Ice Shelf Firn Aquifer

by Shelley MacDonell, Francisco Fernandoy, Paula Villar and Arno Hammann

Water 2021, 13(5), 731; https://doi.org/10.3390/w13050731 - 8 Mar 2021

Cited by 7 | Viewed by 4370

Abstract

In recent decades, several large ice shelves in the Antarctic Peninsula region have experienced significant ice loss, likely driven by a combination of oceanic, atmospheric and hydrological processes. All three areas need further research, however, in the case of the role of liquid [...] Read more.

In recent decades, several large ice shelves in the Antarctic Peninsula region have experienced significant ice loss, likely driven by a combination of oceanic, atmospheric and hydrological processes. All three areas need further research, however, in the case of the role of liquid water the first concern is to address the paucity of field measurements. Despite this shortage of field observations, several authors have proposed the existence of firn aquifers on Antarctic ice shelves, however little is known about their distribution, formation, extension and role in ice shelf mechanics. In this study we present the discovery of saturated firn at three drill sites on the Müller Ice Shelf (67°14′ S; 66°52′ W), which leads us to conclude that either a large contiguous or several disconnected smaller firn aquifers exist on this ice shelf. From the stratigraphic analysis of three short firn cores extracted during February 2019 we describe a new classification system to identify the structures and morphological signatures of refrozen meltwater, identify evidence of superficial meltwater percolation, and use this information to propose a conceptual model of firn aquifer development on the Müller Ice Shelf. The detailed stratigraphic analysis of the sampled cores will provide an invaluable baseline for modelling studies. Full article

(This article belongs to the Special Issue Review and Progress in Hydrological and Meteorological Monitoring of Glaciers)

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