Water

20 pages, 7769 KiB

Open AccessArticle

Development of a New Method to Support a Participatory Planning for Piped Water Supply Infrastructure in Informal Settlements

by Julian Mosbach, Alexander Sonnenburg, Justus Ernst Fiedler and Wilhelm Urban

Water 2022, 14(8), 1316; https://doi.org/10.3390/w14081316 - 18 Apr 2022

Cited by 4 | Viewed by 3137

Abstract

For decades, infrastructure planning in informal settlements has been a major challenge for urban planners and engineers. In particular, the planning process for the rapidly changing heterogeneous structures in these areas usually require individual and non-sustainable solutions. In this report, a method for [...] Read more.

For decades, infrastructure planning in informal settlements has been a major challenge for urban planners and engineers. In particular, the planning process for the rapidly changing heterogeneous structures in these areas usually require individual and non-sustainable solutions. In this report, a method for the sustainable and practical planning of a piped water distribution system (WDS) that generates different expansion variants as a planning support tool is presented. In this tool, all real-world routing options are included in the decision-making process, based on the existing infrastructure, settlement structure, and identifiable open spaces. Additionally, proposals for the localization of the future public water points are supported by methods from Logistics. The consideration of the existing settlement structure and real route lengths (pedestrian walking distance) to a potential water point location lead to very practical and realizable results. The principle of participatory planning was considered, to easily include individual adjustments at any given timeframe. At the same time, automated processes generate fast results. The method is modular and linked to a geographic information system (GIS) to directly visualize the impacts and effects of the planning and decision-making process. Full article

(This article belongs to the Section Urban Water Management)

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18 pages, 2651 KiB

Open AccessArticle

Oscillation Flow Dam Operation Method for Algal Bloom Mitigation

by Jungwook Kim, Jaewon Kwak, Jung Min Ahn, Hongtae Kim, Jihye Jeon and Kyunghyun Kim

Water 2022, 14(8), 1315; https://doi.org/10.3390/w14081315 - 18 Apr 2022

Cited by 7 | Viewed by 2556

Abstract

Green algae play an important role in ecosystems as primary producers, but they can cause algal blooms, which are socio-environmental burdens as responding to them requires water resources from dam reservoirs. This study proposes an alternative for reducing algal blooms through dam operation [...] Read more.

Green algae play an important role in ecosystems as primary producers, but they can cause algal blooms, which are socio-environmental burdens as responding to them requires water resources from dam reservoirs. This study proposes an alternative for reducing algal blooms through dam operation without using additional water resources. A novel oscillation flow concept was suggested: oscillating discharge of dam for irregular flow. To examine its effect, the Environmental Fluid Dynamics Code—National Institute of Environment Research (EFDC-NIER) model was constructed and calibrated for the Namhan River, South Korea, from downstream of the Chungju Dam to downstream of Gangcheon Weir. The water quality in the study area were simulated and analyzed for August 2019, which is when the largest number of harmful cyanobacteria had been reported in recent years. Our results showed that the oscillation flow produced significant variance of flow velocity, and algal bloom density in the Namhan River was reduced by 20–30% through the operation of the Chungju Dam. However, further study and investigation are required before practical application. Full article

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

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16 pages, 2435 KiB

Open AccessArticle

Identification of Key Factors for Urban—Industrial Water Reuse: A Multi-Criteria Analysis Case Study

by Ricardo Isaac, Vivien Viaro, Camila Fonseca and Alana Mânica

Water 2022, 14(8), 1314; https://doi.org/10.3390/w14081314 - 18 Apr 2022

Cited by 2 | Viewed by 2402

Abstract

The industrial reuse of existing municipal wastewater treatment plant (WWTP) effluent can play a major role in improving water security in urbanized regions facing scarcity. As the complexity of engineered direct water reuse is related to various economic, technical, legal, social, environmental, and [...] Read more.

The industrial reuse of existing municipal wastewater treatment plant (WWTP) effluent can play a major role in improving water security in urbanized regions facing scarcity. As the complexity of engineered direct water reuse is related to various economic, technical, legal, social, environmental, and public health aspects, multi-criteria analysis (MCA) is a feasible decision-making tool in this context. The present work aimed to establish the relevant key factors for the application of MCA, wherever plant planning, design, and construction did not previously consider reuse practices. The adopted methodology considers the proposition and valuation of key criteria, based on the existing literature, expert consultations, statistical analysis, and the application of MCA to a real municipal WWTP located in Campinas city (São Paulo State, Brazil). The 13 proposed criteria encompass multiple categories, and their relevance is demonstrated, given the high significance frequencies assigned. The best values are related to effluent quality, health risks, and treatment reliability, in addition to environmental costs and benefits. The application of those criteria in Cooperative Game Theory (CGT) and Compromise Programming (CP) methods is proved to be suitable, considering the characteristics of the studied area (i.e., highly urbanized with a history of water scarcity). Among nine surveyed end-users, the first position in the hierarchy corresponds to the largest industries with the shortest distance from the WWTP. Full article

(This article belongs to the Special Issue Advanced Technologies for Water Reclamation and Reuse)

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21 pages, 6108 KiB

Open AccessArticle

Challenges in Quantifying Losses in a Partly Urbanised Catchment: A South Australian Case Study

by Dinesh C. Ratnayake, Guna A. Hewa and David J. Kemp

Water 2022, 14(8), 1313; https://doi.org/10.3390/w14081313 - 18 Apr 2022

Cited by 2 | Viewed by 2046

Abstract

Quantifying hydrological losses in a catchment is crucial for developing an effective flood forecasting system and estimating design floods. This can be a complicated and challenging task when the catchment is urbanised as the interaction of pervious and impervious (both directly connected and [...] Read more.

Quantifying hydrological losses in a catchment is crucial for developing an effective flood forecasting system and estimating design floods. This can be a complicated and challenging task when the catchment is urbanised as the interaction of pervious and impervious (both directly connected and indirectly connected) areas makes responses to rainfall hard to predict. This paper presents the challenges faced in estimating initial losses (IL) and proportional losses (PL) of the partly urbanised Brownhill Creek catchment in South Australia. The loss components were calculated for 57 runoff generating rainfall events using the non-parametric IL-PL method and parametric method based on two runoff routing models, Runoff Routing Burroughs (RORB) and Rainfall-Runoff Routing (RRR). The analysis showed that the RORB model provided the most representative median IL and PL for the rural portion of the study area as 9 mm and 0.81, respectively. However, none of the methods can provide a reliable loss value for the urban portion because there is no runoff contribution from unconnected areas for each event. However, the estimated non-parametric IL of 1.37 mm can be considered as IL of EIA of the urban portion. Several challenges were identified in the loss estimation process, mainly when selecting appropriate storm events, collecting data with the available temporal resolution, extracting baseflow, and determining the main-stream transmission losses, which reduced the urban flow by 5.7%. The effect of hydrograph shape in non-parametric loss estimation and how combined runoff from the effective impervious area and unconnected (combined indirectly connected impervious and pervious) areas affects the loss estimation process using the RORB and RRR models are further discussed. We also demonstrate the importance of identifying the catchment specific conditions appropriately when quantifying baseflow and runoff of selected events for loss estimation. Full article

(This article belongs to the Section Urban Water Management)

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15 pages, 3419 KiB

Open AccessFeature PaperArticle

Peak Spring Flood Discharge Magnitude and Timing in Natural Rivers across Northern Finland: Long-Term Variability, Trends, and Links to Climate Teleconnections

by Masoud Irannezhad, Saghar Ahmadian, Amin Sadeqi, Masoud Minaei, Behzad Ahmadi and Hannu Marttila

Water 2022, 14(8), 1312; https://doi.org/10.3390/w14081312 - 18 Apr 2022

Cited by 8 | Viewed by 2918

Abstract

In northern regions, like Finland, peak river discharge is principally controlled by maximum snowmelt runoff during spring (March–May). Global warming and climate change extensively influence both the quantity and temporal characteristics of peak discharge in northern rivers by altering snowpack accumulation and melt [...] Read more.

In northern regions, like Finland, peak river discharge is principally controlled by maximum snowmelt runoff during spring (March–May). Global warming and climate change extensively influence both the quantity and temporal characteristics of peak discharge in northern rivers by altering snowpack accumulation and melt processes. This study analyzed peak spring flood discharge (PSFD) magnitude (PSFDM) and timing (PSFDT) in four natural rivers (Simojoki, Kuivajoki, Kiiminkijoki, and Temmesjoki) across northern Finland, in terms of long-term (1967–2011) variability, trends, and links to large-scale climate teleconnections. The PSFDM significantly (p < 0.05) declined in the Simojoki, Kuivajoki, and Kiiminkijoki rivers over time. Both the Simojoki and Kuivajoki rivers also experienced significant decreasing trends of about −0.33 and −0.3 (days year⁻¹), respectively, in the PSFDT during 1967–2011. In these two rivers, the less and earlier PSFDs were principally attributable to the warmer spring seasons positively correlated with the North Atlantic Oscillation (NAO) in recent decades. Moreover, daily precipitation time series corresponding to the PSFD events showed no considerable effects on PSFDM and PSFDT changes in all the natural rivers studied. This suggests that less and earlier historical PSFDs in natural rivers at higher latitudes in northern Finland were primarily induced by warmer springtime temperatures influencing snowpack dynamics. Full article

(This article belongs to the Special Issue River Flow in Cold Climate Environments)

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17 pages, 2226 KiB

Open AccessFeature PaperArticle

Assessment of the Type of Deficit Irrigation Applied during Berry Development in ‘Crimson Seedless’ Table Grapes

by María R. Conesa, Pablo Berríos, Abdelmalek Temnani and Alejandro Pérez-Pastor

Water 2022, 14(8), 1311; https://doi.org/10.3390/w14081311 - 17 Apr 2022

Cited by 7 | Viewed by 2447

Abstract

This work assessed the effects of the sustained (during the whole berry growth) and regulated (at post-veraison) practices of deficit irrigation on water relations, yield components and berry quality in a commercial vineyard of ‘Crimson Seedless’ table grapes. For this, five irrigation treatments [...] Read more.

This work assessed the effects of the sustained (during the whole berry growth) and regulated (at post-veraison) practices of deficit irrigation on water relations, yield components and berry quality in a commercial vineyard of ‘Crimson Seedless’ table grapes. For this, five irrigation treatments were established during a complete irrigation season (from April to October): (i) Control (CTL) irrigated to 110% crop evapotranspiration (ET_c); (ii) Regulated Deficit Irrigation (RDI) irrigated at 50% of CTL during the non-critical period of post-veraison; (iii) Sustained Deficit Irrigation (SDI), irrigated at 50% of CTL throughout the entire berry growing season; (iv) Partial Root-Zone Drying (PRD), irrigated similar to RDI but alternating the irrigation applied on the dry side every 10–14 days; (v) Sustained Partial Root-Zone Drying (SPRD), irrigated as SDI but alternating the irrigation on the dry side every 10–14 days. RDI and PRD received 24% and 28% less water than CTL, respectively. These reductions were higher in SDI and SPRD (65% and 53%, respectively). Total yield was not affected by any DI strategy. Only significantly lower productive values were observed in the weight and height of the berries as compared to CTL. However, the color parameters evaluated increased in all the DI treatments, being slightly higher in SDI and SPRD as compared with RDI and PRD. In addition, total soluble solids (TSS) were significantly higher in SDI, compared to other irrigated counterparts. Our findings showed that the application of water deficit during the entire period of berry growth using SDI and SPRD can be considered for irrigation scheduling in ‘Crimson Seedless’ table grapes when the aim is to solve the trouble of insufficient reddish color of the berries. Full article

(This article belongs to the Section Water Use and Scarcity)

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18 pages, 3031 KiB

Open AccessArticle

Numerical Benchmark Studies on Flow and Solute Transport in Geological Reservoirs

by Shyamal Karmakar, Alexandru Tatomir, Sandra Oehlmann, Markus Giese and Martin Sauter

Water 2022, 14(8), 1310; https://doi.org/10.3390/w14081310 - 17 Apr 2022

Cited by 3 | Viewed by 3098

Abstract

Predicting and characterising groundwater flow and solute transport in engineering and hydrogeological applications, such as dimensioning tracer experiments, rely primarily on numerical modelling techniques. During software selection for numerical modelling, the accuracy of the results, financial costs of the simulation software, and computational [...] Read more.

Predicting and characterising groundwater flow and solute transport in engineering and hydrogeological applications, such as dimensioning tracer experiments, rely primarily on numerical modelling techniques. During software selection for numerical modelling, the accuracy of the results, financial costs of the simulation software, and computational resources should be considered. This study evaluates numerical modelling approaches and outlines the advantages and disadvantages of several simulators in terms of predictability, temporal control, and computational efficiency conducted in a single user and single computational resource set-up. A set of well-established flow and transport modelling simulators, such as MODFLOW/MT3DMS, FEFLOW, COMSOL Multiphysics, and DuMu^X were tested and compared. These numerical simulators are based on three numerical discretisation schemes, i.e., finite difference (FD), finite element (FE), and finite volume (FV). The influence of dispersivity, potentially an artefact of numerical modelling (numerical dispersion), was investigated in parametric studies, and results are compared with analytical solutions. At the same time, relative errors were assessed for a complex field scale example. This comparative study reveals that the FE-based simulators COMSOL and FEFLOW show higher accuracy for a specific range of dispersivities under forced gradient conditions than DuMu^X and MODFLOW/MT3DMS. FEFLOW performs better than COMSOL in regard to computational time both in single-core and multi-core computing. Overall computational time is lowest for the FD-based simulator MODFLOW/MT3DMS while the number of mesh elements is low (here < 12,800 elements). However, for finer discretisation, FE software FEFLOW performs faster. Full article

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14 pages, 4344 KiB

Open AccessArticle

A Study on the Strain-Softening Constitutive Model of Cementitious Sandstone

by Zhongguang Sun, Kequan Wang, Yueming Kang and Wanli Hu

Water 2022, 14(8), 1309; https://doi.org/10.3390/w14081309 - 17 Apr 2022

Cited by 1 | Viewed by 1878

Abstract

In order to further investigate the impacts of the water environment on the mechanical properties of rocks for an engineering project, taking the water-rich conditions in a coal mine as the engineering background, a series of tests were conducted, including the uniaxial compression [...] Read more.

In order to further investigate the impacts of the water environment on the mechanical properties of rocks for an engineering project, taking the water-rich conditions in a coal mine as the engineering background, a series of tests were conducted, including the uniaxial compression test, the conventional triaxial compression test, and the constant axial pressure test on the cementitious sandstone. This was conducted along with the establishment of a multi-linear strain softening constitutive model. According to the tests, the following conclusions can be drawn. Firstly, as the water content increases, the weakening effect of water on the rock mass was obvious. Under various stress paths, the water weakened the rock body to various degrees. In other words, the weakening effect of water on the rock mass was either inhibited or promoted under different stress path conditions Secondly, under various stress paths, the turning point strength and strength variance rate of the rock mass’ mechanical properties decreased linearly with the increase of water content. This further proves that water has a weakening effect on the rock mass, showing that the failure of the specimen changes from brittleness to ductility. Thirdly, the test sample demonstrated different types of damages including the tensile failure, transformation from tensile-shear composite failure to shear failure, and expansion failure under three stress path conditions. In addition, the unloading process demonstrated some dynamic failure characteristics. The research aims to provide some foundational insights for the scientific design and safe construction of the mine and other underground engineering, especially rock mass engineering in the multi-water environment. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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19 pages, 5137 KiB

Open AccessArticle

Coherent Structures at the Interface between Water Masses of Confluent Rivers

by T. P. Lyubimova, A. P. Lepikhin, Ya N. Parshakova and A. V. Bogomolov

Water 2022, 14(8), 1308; https://doi.org/10.3390/w14081308 - 17 Apr 2022

Cited by 3 | Viewed by 1874

Abstract

The paper presents the results of field measurements and numerical modeling of the influence of various factors on the formation of coherent structures in the confluence zone of the Sylva and Chusovaya rivers, which are dammed by the Kamskaya Hydroelectric Power Station (HPS). [...] Read more.

The paper presents the results of field measurements and numerical modeling of the influence of various factors on the formation of coherent structures in the confluence zone of the Sylva and Chusovaya rivers, which are dammed by the Kamskaya Hydroelectric Power Station (HPS). A characteristic feature of the measured parameters in the zone under study is that they experience both seasonal fluctuations and fluctuations of much higher frequency associated with intraday regulation of the HPS operation. These intraday fluctuations give rise to coherent structures with periodicity T~2–10 min, which manifest themselves in the fluctuations of the specific electrical conductivity of water. The flow velocity also experiences significant fluctuations with a sufficiently wide frequency spectrum, although the characteristic period of its fluctuations is less than the period of electrical conductivity fluctuations and is equal to ~1 min. In order to study the features of the formation of such structures, numerical simulation was carried out within the framework of the three-dimensional approach. Calculations were performed for a 300-meter-long stretch of the Chusovaya River, which is located downstream of the confluence of Chusovaya and Sylva rivers and is the site of the Chusovskoy water intake of Perm city. It was found that the intraday irregularity of HPS operation gives rise to the occurrence of vortex structures in this layer, leading to the temporal variation of concentration at a given point of space and the formation of the wave structure of the concentration field at different moments of time. Time period and spatial scale of such vortex structures depend on the ratio of velocities of water masses and difference in their mineralization and, accordingly, in densities. Moreover, the period of fluctuations is proportional to the ratio of flow velocities. These estimations are of fundamental importance for the implementation of stable selective intake of water with required consumer properties under conditions of intraday irregularity of hydroelectric power station operation. Full article

(This article belongs to the Section Hydraulics and Hydrodynamics)

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22 pages, 11359 KiB

Open AccessFeature PaperArticle

Numerical Simulation of Turbulent Flow in Bends and Confluences Considering Free Surface Changes Using the Volume of Fluid Method

by Rawaa Shaheed, Abdolmajid Mohammadian and Xiaohui Yan

Water 2022, 14(8), 1307; https://doi.org/10.3390/w14081307 - 17 Apr 2022

Cited by 3 | Viewed by 3481

Abstract

The impact of secondary flows on the flow velocity in open channel bends and confluences was simulated using three-dimensional (3D) numerical models. The Reynolds-averaged Navier–Stokes equation system was utilized as the governing equations and two different turbulence models were employed in this study: [...] Read more.

The impact of secondary flows on the flow velocity in open channel bends and confluences was simulated using three-dimensional (3D) numerical models. The Reynolds-averaged Navier–Stokes equation system was utilized as the governing equations and two different turbulence models were employed in this study: the standard k-ε model and the realizable k–ε model. In a recent study by the authors, the rigid lid approach was used, which does not allow for vertical displacement of the water surface. In this study, the simulation of free surface displacements was simulated using the volume of fluid free-surface tracking method. The numerical models were evaluated and validated by using the experimental data of a sharply curved channel and a confluent channel. The accuracies of the two turbulence models were evaluated and discussed. This study found that both models can satisfactorily reproduce the experimental data. However, the standard k–ε model performed better for the curved channel case while the Realizable k–ε model performed better for the confluent channel case. Full article

(This article belongs to the Special Issue Modeling of Hydrodynamics and Water Quality in Inland and Coastal Waters)

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18 pages, 3415 KiB

Open AccessArticle

Analysis of Hydrologic Drought Frequency Using Multivariate Copulas in Shaying River Basin

by Jianqin Ma, Bifeng Cui, Xiuping Hao, Pengfei He, Lei Liu and Zhirui Song

Water 2022, 14(8), 1306; https://doi.org/10.3390/w14081306 - 17 Apr 2022

Cited by 7 | Viewed by 2622

Abstract

Droughts, considered one of the most dangerous and costly water cycle expressions, always occurs over a certain region, lasting several weeks or months, and involving multiple variables. In this work, a multivariate approach was used for the statistical characterization of hydrological droughts in [...] Read more.

Droughts, considered one of the most dangerous and costly water cycle expressions, always occurs over a certain region, lasting several weeks or months, and involving multiple variables. In this work, a multivariate approach was used for the statistical characterization of hydrological droughts in Shaying River Basin with data from 1959–2008. The standard runoff index (SRI) and the run theory were employed to defined hydrological drought character variables (duration, severity, and intensity peak). Then, a multivariate joint probability analysis with four symmetric and corresponding asymmetric Archimedean Copulas was presented; and the multivariate frequency analysis with the joint return periods (

T_{a n d}

and

T_{o r}

) were estimated. The results showed that the hydrological droughts have a severity of 4.79 and 5.09, and the drought intensity peak is of 1.35 and 1.50 in Zhoukou station and Luohe station, respectively; the rank correlation coefficients τ are more than 0.5, which means multivariate copulas can effectively describe the joint frequency distributions among multivariate variables. Drought risk shows a spatial variation: the downstream observed at Zhoukou station is characterized by a higher multivariate drought risk. In general, multivariate copulas provide a reliable method when constructing a comprehensive drought index and evaluating multivariate drought characteristics. Thus, this paper can provide useful indications for the multi-dimensional droughts’ risks assessment in Shaying River Basin. Full article

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

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20 pages, 4967 KiB

Open AccessFeature PaperArticle

Semi-Analytical Model for the Evaluation of Shoreline Recession Due to Waves and Sea Level Rise

by Francesco Marini, Sara Corvaro, Stefania Rocchi, Carlo Lorenzoni and Alessandro Mancinelli

Water 2022, 14(8), 1305; https://doi.org/10.3390/w14081305 - 17 Apr 2022

Cited by 5 | Viewed by 1947

Abstract

The climate change process is leading to an increase in the sea level and the storm intensity. The associated shoreline recession can damage coastal facilities and also beaches protected by submerged/emerged breakwaters whose defense action can become ineffective. The application of cross-shore numerical [...] Read more.

The climate change process is leading to an increase in the sea level and the storm intensity. The associated shoreline recession can damage coastal facilities and also beaches protected by submerged/emerged breakwaters whose defense action can become ineffective. The application of cross-shore numerical models does not allow the performance of long-term analyses. In this paper, a semi-analytical model for the evaluation of shoreline recession due to waves and sea-level rise for free and protected beaches is proposed. The model is an extension of the Dean’s approach in which some limitations on the beach profile are overcome and the effects of breakwaters on the wave height (wave transmission) and on the water level (piling-up) are considered. The model takes into account a wide range of parameters for wave, sea level, beach profile, and breakwater characteristics. Among the breakwater parameters, the freeboard and the berm width are found to mainly affect the shoreline recession. For submerged breakwaters, an optimal value of the freeboard can be computed depending on the sea level and the offshore wave characteristics. The results of the model are then used to find prediction relations of the shoreline recession, with r² > 0.99, for both free and protected beaches, depending on the main hydrodynamic/geometrical characteristics. Full article

(This article belongs to the Special Issue Ocean Wave Studies for Engineering Applications)

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17 pages, 3772 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

New Challenges towards Smart Systems’ Efficiency by Digital Twin in Water Distribution Networks

by Helena M. Ramos, Maria Cristina Morani, Armando Carravetta, Oreste Fecarrotta, Kemi Adeyeye, P. Amparo López-Jiménez and Modesto Pérez-Sánchez

Water 2022, 14(8), 1304; https://doi.org/10.3390/w14081304 - 17 Apr 2022

Cited by 42 | Viewed by 6040

Abstract

Nowadays, in the management of water distribution networks (WDNs), particular attention is paid to digital transition and the improvement of the energy efficiency of these systems. New technologies have been developed in the recent years and their implementation can be crucial to achieve [...] Read more.

Nowadays, in the management of water distribution networks (WDNs), particular attention is paid to digital transition and the improvement of the energy efficiency of these systems. New technologies have been developed in the recent years and their implementation can be crucial to achieve a sustainable level of water networks, namely, in water and energy losses. In particular, Digital Twins (DT) represents a very innovative technology, which relies on the integration of virtual network models, optimization algorithms, real time data collection, and smart actuators information with Geographic Information System (GIS) data. This research defines a new methodology for an efficient application of DT expertise within water distribution networks. Assuming a DMA of a real water distribution network as a case study, it was demonstrated that a fast detection of leakage along with an optimal setting of pressure control valves by means of DT together with an optimization procedure can ensure up to 28% of water savings, contributing to significantly increase the efficiency of the whole system. Full article

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

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13 pages, 6690 KiB

Open AccessArticle

A Simple Scaling Analysis of Rainfall in Andalusia (Spain) under Different Precipitation Regimes

by María del Carmen Casas-Castillo, Raül Rodríguez-Solà, Alba Llabrés-Brustenga, Amanda Penélope García-Marín, Javier Estévez and Xavier Navarro

Water 2022, 14(8), 1303; https://doi.org/10.3390/w14081303 - 16 Apr 2022

Cited by 6 | Viewed by 2459

Abstract

A simple scaling analysis was performed in Andalusia (Spain) using daily records from 377 selected stations covering the temporal period between 1870 and 2018. Since Andalusia is a region of considerable climatic variety, with notably wet areas as well as extremely dry zones, [...] Read more.

A simple scaling analysis was performed in Andalusia (Spain) using daily records from 377 selected stations covering the temporal period between 1870 and 2018. Since Andalusia is a region of considerable climatic variety, with notably wet areas as well as extremely dry zones, this study is useful to investigate the relationship between the simple scaling parameter value and the characteristic rainfall regime of a place. Despite the great correspondence with the average annual precipitation (PRCPTOT), a clear dependence on rainfall irregularity was observed, revealed by the ratio of the maximum daily precipitation and PRCPTOT, as well the wet spells frequency index CWD. The spatial distribution of the simple scaling parameter captured the increasing influence of the Mediterranean Sea towards the East. The easternmost dry areas are clearly influenced by Mediterranean disturbances, with a high proportion of convective rainfall and an irregular rainfall pattern. Using a simple scaling parameter, the generalized equations of the intensity-duration-frequency (IDF) curves, of great hydrological interest were calculated for the eight Andalusian provincial capitals. Moreover, the temporal trends of this parameter in the four past decades were studied in the different areas with the aim of determining if changes in their rainfall patterns due to global warming could be detected. Full article

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21 pages, 5977 KiB

Open AccessArticle

Comparative Multi-Criteria Assessment of Hydrological Vulnerability—Case Study: Drainage Basins in the Northeast Region of Romania

by Andra-Cosmina Albulescu, Ionuț Minea, Daniel Boicu and Daniela Larion

Water 2022, 14(8), 1302; https://doi.org/10.3390/w14081302 - 16 Apr 2022

Cited by 8 | Viewed by 2584

Abstract

Hydrological vulnerability (HV) is a (changing) underlying condition in all drainage basins, depending on the dynamics of the potentially dangerous hydrological phenomena, the particularities of drainage networks, land use patterns, and processes that shape landforms in extensive periods. The socioeconomic attributes and the [...] Read more.

Hydrological vulnerability (HV) is a (changing) underlying condition in all drainage basins, depending on the dynamics of the potentially dangerous hydrological phenomena, the particularities of drainage networks, land use patterns, and processes that shape landforms in extensive periods. The socioeconomic attributes and the hydrotechnical infrastructure add up to the manifestation of this type of vulnerability. In this paper, we assess the HV levels of 81 drainage basins in the NE of Romania for three distinctive periods (1990–1999, 2000–2009, 2010–2018), using a multi-criteria approach. Two classical multi-criteria decision making (MCDM) methods were combined in order to evaluate the HV according to factors that refer to floods and hydrological drought occurrences, hydrotechnical structure coverage, the drainage network, land use, and landforms characteristics. The Analytic Hierarchy Process (AHP) was applied to weigh these factors and the resulting relative importance values were integrated in the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), by which the alternatives represented by the catchments were ranked. The attenuation of the HV through time follows an East–West direction, from the lower elevations of the Moldavian Plateau to the heights of the Carpathians. Hydrological droughts are more likely to occur in the Eastern part of the analyzed territory, while the western section displays a certain propensity for floods. The results may be used by local and national authorities in order to improve the hydrological risk mitigation strategies, and to develop more targeted water management projects, properly calibrated to the conditions of the Northeast Development Region in Romania. Full article

(This article belongs to the Special Issue Flood and Other Hydrogeomorphological Risk Management and Analysis)

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22 pages, 6234 KiB

Open AccessArticle

Runoff Reduction Effects at Installation of LID Facilities under Different Climate Change Scenarios

by Seungwook Lee, Daye Kim, Seungjin Maeng, Muhammad Azam and Bongguk Lee

Water 2022, 14(8), 1301; https://doi.org/10.3390/w14081301 - 16 Apr 2022

Cited by 8 | Viewed by 2393

Abstract

In order to prepare for floods and droughts that occur as a result of climate change, various studies in water-related fields are being carried out in various countries around the world. Among them, special attention is being paid to the low-impact development (LID) [...] Read more.

In order to prepare for floods and droughts that occur as a result of climate change, various studies in water-related fields are being carried out in various countries around the world. Among them, special attention is being paid to the low-impact development (LID) technique. This study measured the annual maximum daily rainfall data from 2019 to 2100 by climate change scenario, which is the annual maximum daily rainfall series observed for rainfall stations, and tested the hydrological data using statistical analysis. After determining whether the data could be analyzed, the probability distribution was selected, and the parameters of the selected probability distribution were calculated using the L-moment method for each rainfall station. The probabilities of rainfall data were derived using GEV distribution, and the United States Environmental Protection Agency Storm Water Management Model (SWMM), a runoff simulation program, was used to compare and analyze the runoff reduction rate before and after the installation of a permeable pavement as an LID facility. The results of the analysis showed that representative concentration pathway (RCP) 4.5 and RCP 8.5 had the effect of reducing the runoff for more than 100 years at a 30% reduction rate compared with before installation. Full article

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

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16 pages, 757 KiB

Open AccessArticle

An Improved Transfer Learning Model for Cyanobacterial Bloom Concentration Prediction

by Jianjun Ni, Ruping Liu, Yingqi Li, Guangyi Tang and Pengfei Shi

Water 2022, 14(8), 1300; https://doi.org/10.3390/w14081300 - 16 Apr 2022

Cited by 8 | Viewed by 2339

Abstract

The outbreak of cyanobacterial blooms is a serious water environmental problem, and the harm it brings to aquatic ecosystems and water supply systems cannot be underestimated. It is very important to establish an accurate prediction model of cyanobacterial bloom concentration, which is a [...] Read more.

The outbreak of cyanobacterial blooms is a serious water environmental problem, and the harm it brings to aquatic ecosystems and water supply systems cannot be underestimated. It is very important to establish an accurate prediction model of cyanobacterial bloom concentration, which is a challenging issue. Machine learning techniques can improve the prediction accuracy, but a large amount of historical monitoring data is needed to train these models. For some waters with an inconvenient geographical location or frequent sensor failures, there are not enough historical data to train the model. To deal with this problem, a fused model based on a transfer learning method is proposed in this paper. In this study, the data of water environment with a large amount of historical monitoring data are taken as the source domain in order to learn the knowledge of cyanobacterial bloom growth characteristics and train the prediction model. The data of the water environment with a small amount of historical monitoring data are taken as the target domain in order to load the model trained in the source domain. Then, the training set of the target domain is used to participate in the inter-layer fine-tuning training of the model to obtain the transfer learning model. At last, the transfer learning model is fused with a convolutional neural network to obtain the prediction model. Various experiments are conducted for a 2 h prediction on the test set of the target domain. The results show that the proposed model can significantly improve the prediction accuracy of cyanobacterial blooms for the water environment with a low data volume. Full article

(This article belongs to the Special Issue Using Artificial Intelligence for Smart Water Management)

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15 pages, 635 KiB

Open AccessArticle

Green Energy and Water Resource Management: A Case Study of Fishery and Solar Power Symbiosis in Taiwan

by Han-Shen Chen and Hung-Yu Kuo

Water 2022, 14(8), 1299; https://doi.org/10.3390/w14081299 - 15 Apr 2022

Cited by 5 | Viewed by 4088

Abstract

Renewable energy development is a key pathway for mitigating climate change. The Taiwan government has been actively developing low carbon green energy with solar photovoltaic technology and wind power as their primary development projects. Cigu Taiwan provides an ideal research site to examine [...] Read more.

Renewable energy development is a key pathway for mitigating climate change. The Taiwan government has been actively developing low carbon green energy with solar photovoltaic technology and wind power as their primary development projects. Cigu Taiwan provides an ideal research site to examine tradeoffs between ecological conservation, marine fisheries, and green power development, and the factors affect commitments to ecological conservation in the face of these tradeoffs. This research investigates the fishery and electricity symbiosis project in Cigu through a novel combination of the theory of planned behavior and the contingent valuation method to analyze the factors influencing the local residents’ behavioral intentions to safeguard ecological achievements in ecologically fragile areas through conservation trust funds. Analysis of survey responses from a convenience sample of 715 residents and resource users in the Cigu area reports that attitudes (ATT), subjective norms (SN), perceived behavioral control (PBC), environmental concern (EC), and environmental risk (ER) significantly influence the behavioral intention to pay eco-compensation fees; the local residents’ willingness to pay for the conservation trust funds was NTD 621.4/year (USD 21.9/year), and decreased to NTD 545.9/year (USD 19.2/year) after the implementation of fishery and electricity symbiosis. The discussion section argues that the drivers of ATT, SN, PBC, EC, and ER can be used by policy makers to direct local residents’ intentions and behavior toward conserving ecological achievements in fragile eco-environmental areas through payments for ecosystem services. Thus, this strategy can improve the sustainability of ecological and environmental restoration programs. Full article

(This article belongs to the Special Issue Relationship of Energy and Water Resource Availability)

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17 pages, 2016 KiB

Open AccessArticle

The Impacts of Different Anthropogenic Disturbances on Macroinvertebrate Community Structure and Functional Traits of Glacier-Fed Streams in the Tianshan Mountains

by Yuwei Liu, Yilin Tian, Yingzhi Gao, Dong Cui, Wei Zhang, Ziwei Jiao, Fulong Yao, Zhenxing Zhang and Haijun Yang

Water 2022, 14(8), 1298; https://doi.org/10.3390/w14081298 - 15 Apr 2022

Cited by 5 | Viewed by 2763

Abstract

Macroinvertebrates are sensitive to environmental disturbances, however, the effects of human activities on macroinvertebrate community structures and functional traits in glacier-fed streams are concerning. To elucidate the effects of horse, cattle and sheep grazing, hot spring scenic development, and historic iron ore mine [...] Read more.

Macroinvertebrates are sensitive to environmental disturbances, however, the effects of human activities on macroinvertebrate community structures and functional traits in glacier-fed streams are concerning. To elucidate the effects of horse, cattle and sheep grazing, hot spring scenic development, and historic iron ore mine development on macroinvertebrate communities, we conducted a study in three glacier-fed streams of the Tianshan Mountains in northwest China in April 2021. Our results showed that the species richness and density significantly decreased due to grazing (p < 0.05). There were more taxa with resilience traits such as “small size at maturity” in the grazing stream. The EPT richness and density affected by hot spring scenic development significantly decreased compared to the undisturbed point (p < 0.05). There was a significant increase in taxa with resistance traits such as “bi-or-multivoltine” in the hot spring stream. The stream affected by historic mine development is currently in the self-recovery stage following the closure of the mine ten years ago. Additionally, the species richness, EPT richness, and density at the mining site were significantly higher than the source site (p < 0.05), reflecting that the habitat fragmentation caused by previous mining activities prevented the upward dispersal of macroinvertebrates. The taxa in the mining stream were also characterized by higher resistance traits such as “abundant occurrence in drift”. These results were attributed to the impacts of human disturbance on habitat stability, habitat heterogeneity, water quality, and material cycling of stream ecosystems, indicating human disturbance on the efficiency of resource utilization and functional diversification. In addition, our results showed that functional indicators of macroinvertebrate communities are helpful for monitoring and evaluating habitat conditions. Full article

(This article belongs to the Special Issue The Ecological Quality Assessment of Freshwater Ecosystems: Present and Future)

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22 pages, 1798 KiB

Open AccessReview

Environmental Fate of Metal Nanoparticles in Estuarine Environments

by Michele Arienzo and Luciano Ferrara

Water 2022, 14(8), 1297; https://doi.org/10.3390/w14081297 - 15 Apr 2022

Cited by 8 | Viewed by 3091

Abstract

In the last decade, metal engineered nanomaterials (ENMs) have seen an exponential use in many critical technologies and products, as well an increasing release into the environment. Coastal ecosystems worldwide may receive ENM-polluted waters and wastes, with a consequent alteration of habitats and [...] Read more.

In the last decade, metal engineered nanomaterials (ENMs) have seen an exponential use in many critical technologies and products, as well an increasing release into the environment. Coastal ecosystems worldwide may receive ENM-polluted waters and wastes, with a consequent alteration of habitats and contamination of aquatic biota. There is a scarcity of data regarding the fate of these emerging contaminants in such environments. Open issues include the determination of the sources, the quantification of the interactions with marine sediments, the bioaccumulation pathways, the ecotoxicology on marine fauna and the identification of the principal biotic and abiotic factors that may alter metal ENMs toxicity. Little is known about their potential transference into the food web, as well toxicity features and co-stressors of single or multiple ENMs under laboratory and real environmental conditions for various taxonomic phyla. This review reports current knowledge on the ecological impact of ENMs under the complex environmental conditions of estuary systems, identifies gaps in current knowledge and provides directions for future research. Full article

(This article belongs to the Special Issue New Insights on Pollution and Remediation of Trace Elements in Coastal and Estuarine Sediments)

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10 pages, 1836 KiB

Open AccessFeature PaperArticle

Ranking Three Water Sensitive Urban Design (WSUD) Practices Based on Hydraulic and Water Quality Treatment Performance: Implications for Effective Stormwater Treatment Design

by An Liu, Prasanna Egodawatta and Ashantha Goonetilleke

Water 2022, 14(8), 1296; https://doi.org/10.3390/w14081296 - 15 Apr 2022

Cited by 5 | Viewed by 3099

Abstract

Bioretention basins, constructed wetlands and roadside swales are among the most common Water-Sensitive Urban Design (WSUD) or stormwater quality treatment systems. Although these systems can reduce stormwater quantity and improve quality, their hydraulic and water quality treatment performances are different. The aim of [...] Read more.

Bioretention basins, constructed wetlands and roadside swales are among the most common Water-Sensitive Urban Design (WSUD) or stormwater quality treatment systems. Although these systems can reduce stormwater quantity and improve quality, their hydraulic and water quality treatment performances are different. The aim of this study was to investigate the hydraulic and water quality performance of a bioretention basin, a constructed wetland and a roadside swale by analyzing monitored water quantity and quality data from a range of rainfall events using a ranking approach. The study outcomes showed that a bioretention basin performed better in relation to peak flow and runoff volume reduction while the constructed wetland tended to produce better outflow water quality. The roadside swale had a relatively lower capacity for treating stormwater. These results suggest that a bioretention basin could be the preferred option when the primary requirement is water quantity improvement. However, if water quality improvement is the primary consideration, a constructed wetland could be more efficient. Additionally, when designing a treatment train, it appears to be preferable to place a bioretention basin prior to a constructed wetland. Further, a swale appears to be more appropriate for use as a pretreatment device. The research study outcomes will contribute to effective stormwater treatment design. Full article

(This article belongs to the Special Issue Efficient Design, Operation, and Management of Urban Stormwater Systems)

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22 pages, 5517 KiB

Open AccessArticle

Monitoring the Chl-a Distribution Details in the Yangtze River Mouth Using Satellite Remote Sensing

by Juan Bu, Lina Cai, Xiaojun Yan, Huanzhi Xu, Haiyan Hu and Jingjing Jiang

Water 2022, 14(8), 1295; https://doi.org/10.3390/w14081295 - 15 Apr 2022

Cited by 6 | Viewed by 2761

Abstract

The distribution of chlorophyll-a (Chl-a) in the Yangtze River Mouth area was analyzed using a new Chl-a inversion model (PMS-C) based on the relationship between in situ Chl-a and GF-4 PMS band combinations. Combining GF-4 PMS with HY-C CZI, this paper revealed that: [...] Read more.

The distribution of chlorophyll-a (Chl-a) in the Yangtze River Mouth area was analyzed using a new Chl-a inversion model (PMS-C) based on the relationship between in situ Chl-a and GF-4 PMS band combinations. Combining GF-4 PMS with HY-C CZI, this paper revealed that: (1) Chl-a concentration in Yangtze River Mouth was in the range of 2–6 µg/L, being higher in the west than in the east. The high Chl-a area was mainly distributed near the mouth of the Yangtze River and the Chl-a value was in the range of 3.7 µg/L to 5.9 µg/L. Chl-a concentration is higher in spring and summer than in autumn and winter, with a Chl-a concentration difference of 1–2 µg/L. Chl-a downstream of islands and bridges increased by 0.5–1.7 µg/L compared with upstream. (2) Short-term (within 3 h) changes of Chl-a concentration were effectively detected. In summer and autumn, Chl-a obtained at 13:30 in the noon was generally lower than Chl-a obtained at around 10:30 in the morning and it decreased by nearly 0.1–4 μg/L within three hours on the same day. In winter, the concentration of Chl-a decreased in the range of 0–1.9 μg/L. Generally, within three hours, Chl-a in the downstream of the island decreased significantly from 5 μg/L to about 3.8 μg/L, and Chl-a downstream of piers decreased from 3.7 μg/L to about 3 μg/L. (3) Environmental factors including seawater temperature, illumination, and nutrients, as well as dynamic factors such as wind and tidal current can induce Chl-a change in the Yangtze River Mouth. Short-term change of Chl-a concentration is closely related to the specific hydrodynamic conditions, nutrients, and lighting conditions. Full article

(This article belongs to the Special Issue Eutrophication Management in Coastal Zones for Better Water Quality)

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15 pages, 4982 KiB

Open AccessArticle

Monitoring the Process of Anaerobic Digestion of Native and Microwave Pre-Treated Sludge by Dielectric and Rheological Measurements

by Zoltán Jákói, Cecilia Hodúr and Sándor Beszédes

Water 2022, 14(8), 1294; https://doi.org/10.3390/w14081294 - 15 Apr 2022

Cited by 6 | Viewed by 2575

Abstract

The anaerobic digestion (AD) of wastewater sludge presents a promising and efficient method of wastewater and sludge treatment, as it can lower the organic content of sludge while producing a renewable source of energy—biogas—at the same time. However, using native, non-treated industrial wastewater [...] Read more.

The anaerobic digestion (AD) of wastewater sludge presents a promising and efficient method of wastewater and sludge treatment, as it can lower the organic content of sludge while producing a renewable source of energy—biogas—at the same time. However, using native, non-treated industrial wastewater sludge as a substrate for AD may present difficulties, hence we focused our research primarily on the applicability of measuring techniques—viscosity and dielectric measurement. One of our research goals was to investigate the presence of any connection between the aforementioned properties and the overall biogas production, in order to prove whether these measurement techniques were capable of monitoring the process of AD. Our other aim was to investigate how microwave (MW) pre-treatment affected the anaerobic fermentation. Our results revealed that in terms of total biogas yield, microwave irradiation could enhance fermentation by 14%, and also reduced the viscosity of the fermentation media by 13%. However, microwave irradiation did not change the overall tendencies of the AD process regarding these aspects. Moreover, it was discovered that dielectric and absolute viscosity measurements were effective methods for monitoring the fermentation. Additionally, a correlation was found between the accumulating biogas yield, the dielectric constant and loss factor, and the absolute viscosity of the digested media—each of these share a similarity in tendency and can indicate the occurrence of different phases during batch anaerobic fermentation. Full article

(This article belongs to the Topic Anaerobic Digestion Processes)

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18 pages, 1286 KiB

Open AccessArticle

Assessing the Climate Resilience of Community-Managed Water Supplies in Ethiopia and Nepal

by Anisha Nijhawan, Guy Howard, Moti Poudel, Maria Pregnolato, Yuen Tung Eunice Lo, Anish Ghimire, Manish Baidya, Abraham Geremew, Adrian Flint and Yohannes Mulugeta

Water 2022, 14(8), 1293; https://doi.org/10.3390/w14081293 - 15 Apr 2022

Cited by 9 | Viewed by 4029

Abstract

Understanding the resilience of water supplies to climate change is becoming an urgent priority to ensure health targets are met. Addressing systemic issues and building the resilience of community-managed supplies, which serve millions of people in rural LMIC settings, will be critical to [...] Read more.

Understanding the resilience of water supplies to climate change is becoming an urgent priority to ensure health targets are met. Addressing systemic issues and building the resilience of community-managed supplies, which serve millions of people in rural LMIC settings, will be critical to improve access to safe drinking water. The How Tough is WASH (HTIW) framework to assess resilience was applied to community-managed water supplies in Ethiopia and Nepal to assess the effectiveness of this framework in field conditions. The resilience of these water supplies was measured along six domains—the environment, infrastructure, management, institutional support, community governance and supply chains—that can affect how they respond to climate change effects. We found that the HTIW framework provided an objective measure of resilience and could be used to rank water supplies in order of priority for action. We also found that systemic issues could be identified. The tools and methods used in the framework were easy to deploy by field research teams. The water supplies studied in Ethiopia and Nepal had low to moderate resilience to climate change. Service management and institutional support were weak in both countries. The data from Ethiopia and Nepal suggests that many water supplies in rural and small-town communities are unlikely to be resilient to future climate change without increased investment and support. The use of simple frameworks such as HTIW will be important in supporting decisions around such investments by identifying priority communities and actions. Full article

(This article belongs to the Section Water and Climate Change)

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19 pages, 3002 KiB

Open AccessArticle

Probabilistic Framework Allocation on Underwater Vehicular Systems Using Hydrophone Sensor Networks

by Pravin R. Kshirsagar, Hariprasath Manoharan, S. Shitharth, Abdulrhman M. Alshareef, Dilbag Singh and Heung-No Lee

Water 2022, 14(8), 1292; https://doi.org/10.3390/w14081292 - 15 Apr 2022

Cited by 8 | Viewed by 2170

Abstract

This article emphasis the importance of constructing an underwater vehicle monitoring system to solve various issues that are related to deep sea explorations. For solving the issues, conventional methods are not implemented, whereas a new underwater vehicle is introduced which acts as a [...] Read more.

This article emphasis the importance of constructing an underwater vehicle monitoring system to solve various issues that are related to deep sea explorations. For solving the issues, conventional methods are not implemented, whereas a new underwater vehicle is introduced which acts as a sensing device and monitors the ambient noise in the system. However, the fundamentals of creating underwater vehicles have been considered from conventional systems and the new formulations are generated. This innovative sensing device will function based on the energy produced by the solar cells which will operate for a short period of time under the water where low parametric units are installed. In addition, the energy consumed for operating a particular unit is much lesser and this results in achieving high reliability using a probabilistic path finding algorithm. Further, two different application segments have been solved using the proposed formulations including the depth of monitoring the ocean. To validate the efficiency of the proposed method, comparisons have been made with existing methods in terms of navigation output units, rate of decomposition for solar cells, reliability rate, and directivity where the proposed method proves to be more efficient for an average percentile of 64%. Full article

(This article belongs to the Special Issue AI and Deep Learning Applications for Water Management)

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20 pages, 4440 KiB

Open AccessArticle

Short-Term Bathwater Demand Forecasting for Shared Shower Rooms in Smart Campuses Using Machine Learning Methods

by Ganggang Zhang, Yingbin Hu, Dongxuan Yang, Lei Ma, Mengqi Zhang and Xinliang Liu

Water 2022, 14(8), 1291; https://doi.org/10.3390/w14081291 - 15 Apr 2022

Cited by 5 | Viewed by 2564

Abstract

Water scarcity is a growing threat to humankind. At university campuses, there is a need for shared shower room managers to forecast the demand for bath water accurately. Accurate bath water demand forecasts can decrease the costs of water heating and pumping, reduce [...] Read more.

Water scarcity is a growing threat to humankind. At university campuses, there is a need for shared shower room managers to forecast the demand for bath water accurately. Accurate bath water demand forecasts can decrease the costs of water heating and pumping, reduce overall energy consumption, and improve student satisfaction (due to stability of bath water supply and bathwater temperature). We present a case study conducted at Capital Normal University (Beijing, China), which provides shared shower rooms separately for female and male students. Bath water consumption data are collected in real-time through shower tap controllers to forecast short-term bath water consumption in the shower buildings. We forecasted and compared daily and hourly bath water demand using the autoregressive integrated moving average, random forests, long short-term memory, and neural basis expansion analysis time series-forecasting models, and assessed the models’ performance using the mean absolute error, mean absolute percentage error, root-mean-square error, and coefficient of determination equations. Subsequently, covariates such as weather information, student behavior, and calendars were used to improve the models’ performance. These models achieved highly accurate forecasting for all the shower room areas. The results imply that machine learning methods outperform statistical methods (particularly for larger datasets) and can be employed to make accurate bath water demand forecasts. Full article

(This article belongs to the Section Urban Water Management)

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16 pages, 4857 KiB

Open AccessArticle

Wetland Resource Use and Conservation Attitudes of Rural vs. Urban Dwellers: A Comparative Analysis in Thohoyandou, Limpopo Province, South Africa

by Ndidzulafhi Innocent Sinthumule and Khathutshelo Hildah Netshisaulu

Water 2022, 14(8), 1290; https://doi.org/10.3390/w14081290 - 15 Apr 2022

Cited by 11 | Viewed by 7311

Abstract

Although wetlands provide a variety of goods and services to people and ecosystems, they are the most threatened ecosystem in the world because they are easily degraded. Thus, efforts to protect the remaining wetlands are critical if this resource is to continue providing [...] Read more.

Although wetlands provide a variety of goods and services to people and ecosystems, they are the most threatened ecosystem in the world because they are easily degraded. Thus, efforts to protect the remaining wetlands are critical if this resource is to continue providing environmental, cultural, and economic goods and services. Central to the conservation and management of wetlands is understanding the attitudes of the people bordering wetlands. This study aimed to analyse wetland resource use and conservation attitudes of urban vs. rural dwellers of Thohoyandou, Limpopo Province, South Africa. Interview-administered questionnaires and observation were the methods used for data collection. Systematic random sampling was used to obtain a sample of 282 in urban and 312 households in rural areas. Descriptive statistics (frequencies, percentages) were used to summarize the data. Chi-square (χ²) tests were applied using Microsoft Excel (Microsoft Corporation, Redmond, Washington, WA, USA) in order to determine whether responses occurred with equal probability. Differences were considered to be significant at p ≤ 0.05. The study found that wetlands are more important in the lives and livelihoods of people in rural areas (92.9%) compared with urban areas (26.6%) of Thohoyandou. Human land use activities in wetlands (especially cultivation and infrastructural development) have degraded and destroyed wetlands—particularly those located in urban areas. The attitudes of respondents were generally positive both in urban and rural areas regarding the need for conservation and rehabilitation/restoration of wetlands. The study concluded that positive attitudes alone are insufficient to save and protect the wetlands. The responsible authorities should implement existing legislation to complement the positive attitudes of people and, importantly, they should work with communities towards the conservation of wetlands. Full article

(This article belongs to the Section Ecohydrology)

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15 pages, 3266 KiB

Open AccessArticle

Migration Law of LNAPLs in the Groundwater Level Fluctuation Zone Affected by Freezing and Thawing

by Jing Zhou, Minghao Pan, Chuping Chang, Ao Wang, Yongqi Wang and Hang Lyu

Water 2022, 14(8), 1289; https://doi.org/10.3390/w14081289 - 15 Apr 2022

Cited by 4 | Viewed by 2286

Abstract

Freezing and thawing can cause dynamic fluctuations of the groundwater level, resulting in the migration and retention of LNAPLs. However, this process is difficult to observe visually, and a suitable simulation method for its quantitative calculation is lacking. In this study, a numerical [...] Read more.

Freezing and thawing can cause dynamic fluctuations of the groundwater level, resulting in the migration and retention of LNAPLs. However, this process is difficult to observe visually, and a suitable simulation method for its quantitative calculation is lacking. In this study, a numerical simulation is established by coupling the HYDRUS-1D software and the TOUGH program to realize dynamic simulation of the entire process of soil temperature changes, water migration, water level fluctuation, and redistribution of LNAPLs during the freeze–thaw process. The results of the study show that the process of soil freezing and thawing causes water migration, which in turn causes groundwater level fluctuation, leading to the migration and redistribution of LNAPLs within the water level fluctuation zone. In this process, the soil particle size and porosity control the response degree and speed of the water level under freezing and thawing and the spatiotemporal distribution of LNAPLs by affecting the soil temperature, capillary force, and water migration. The migration ability of free LNAPLs is determined by their own density and viscosity; the retention of residual LNAPLs is affected by soil porosity and permeability as well as LNAPL viscosity. The results of this study can not only be used to develop a simulation method for the migration and retention mechanism of LNAPLs in cold regions but also serve as a scientific and theoretical basis for LNAPL pollution control in seasonal frozen soil regions. Full article

(This article belongs to the Special Issue River Ecological Restoration and Groundwater Artificial Recharge II)

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13 pages, 1817 KiB

Open AccessArticle

Continuous Cultivation of Microalgae in Cattle Slaughterhouse Wastewater Treated with Hydrodynamic Cavitation

by Ruly Terán Hilares, Fabio P. Sánchez Vera, Gilberto J. Colina Andrade, Kevin Tejada Meza, Jaime Cárdenas García and David Alfredo Pacheco Tanaka

Water 2022, 14(8), 1288; https://doi.org/10.3390/w14081288 - 15 Apr 2022

Cited by 6 | Viewed by 3186

Abstract

Cattle slaughtering produce large amounts of wastewater containing high concentrations of organic matter and nutrients and requires significant treatment before disposal or reutilization. However, the nutrients contained can be valued as a medium for microalgal biomass generation. In this work, hydrodynamic cavitation (HC) [...] Read more.

Cattle slaughtering produce large amounts of wastewater containing high concentrations of organic matter and nutrients and requires significant treatment before disposal or reutilization. However, the nutrients contained can be valued as a medium for microalgal biomass generation. In this work, hydrodynamic cavitation (HC) followed by membrane filtration or biological (microalgae cultivation) treatment in continuous mode were performed. From cattle slaughterhouse wastewater (CSW), by the effect of HC treatment with air injection in batch mode, more than 20% of the chemical oxygen demand (COD) was removed. In a continuous HC process, the COD content in output was 324 mg O₂/L, which is 68% lower than the supplied CSW. After that, 76% of residual COD was removed by filtration through a tubular alumina membrane (600 nm). Finally, 85% of residual COD after HC treatment in 24 h in a batch mode was removed by microalgae. On the other hand, the COD concentration in the output was around 59 mg O₂/L in continuous mode, which represents 85–93% COD removal. The process involving HC and microalgae growing looks promising since in addition to water treatment, the microalgae produced could be valued in a biorefinery concept. Full article

(This article belongs to the Topic Water Reclamation and Reuse)

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15 pages, 414 KiB

Open AccessArticle

The Gap between Willingness and Behavior: The Use of Recycled Water for Toilet Flushing in Beijing, China

by Yizhe Ding, Xiaojun Liu and Li Li

Water 2022, 14(8), 1287; https://doi.org/10.3390/w14081287 - 15 Apr 2022

Cited by 4 | Viewed by 2254

Abstract

Promoting the use of recycled water is an effective way to solve the problem of urban water shortage. In order to promote the utilization of recycled water, this study identified the influential factors determining the differences between willingness and behavior to use recycled [...] Read more.

Promoting the use of recycled water is an effective way to solve the problem of urban water shortage. In order to promote the utilization of recycled water, this study identified the influential factors determining the differences between willingness and behavior to use recycled water for toilet flushing. Binary logistic regression models of willingness and behavior were analyzed and the data came from 1195 Beijing residents in communities where recycled water was available for toilet flushing. The results are as follows: First, the proportion of those willing to use recycled water (92%) was significantly higher than those who actually did so (35.2%); thus, higher willingness to use recycled water did not necessarily lead to higher using behavior. Second, different factors influenced willingness and behavior, with the willingness mainly influenced by cognitive and attitudinal factors, and the behavior dependent on external environmental factors such as the convenience of installation and promotion measures. Third, the convenience of the installation of recycled water facilities is the most important factor influencing both willingness and behavior, and inconvenient facilities are the main factor hindering the use of recycled water. Full article

(This article belongs to the Section Water and One Health)

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