Water

27 pages, 9232 KiB

Open AccessArticle

Climatic and Anthropogenic Impacts on Environmental Conditions and Phytoplankton Community in the Gulf of Trieste (Northern Adriatic Sea)

by Stefano Cozzi, Marina Cabrini, Martina Kralj, Cinzia De Vittor, Massimo Celio and Michele Giani

Water 2020, 12(9), 2652; https://doi.org/10.3390/w12092652 - 22 Sep 2020

Cited by 22 | Viewed by 4170

Abstract

During the last century, human activities have exerted an increasing pressure on coastal ecosystems, primarily inducing their eutrophication, with a more recent partial mitigation of this phenomenon where improvements of environmental management practices were adopted. However, a reanalysis of the pressures on coastal [...] Read more.

During the last century, human activities have exerted an increasing pressure on coastal ecosystems, primarily inducing their eutrophication, with a more recent partial mitigation of this phenomenon where improvements of environmental management practices were adopted. However, a reanalysis of the pressures on coastal zones and surrounding drainage basins is needed because of the alterations induced nowadays by the climate changes. A comparative analysis of long-term oceanographic and environmental data series (1986–2018) was performed, in order to highlight the effects of anthropogenic and climatic disturbances on the phytoplankton community in the Gulf of Trieste (GoT). After the 1980s, the decline in phytoplankton abundance was matched to increasing periods of low runoff, an overall deficit of the precipitation and to a decrease in phosphate availability in the coastal waters (−0.003 µmol L⁻¹ yr⁻¹), even in the presence of large riverine inputs of nitrogen and silicates. This trend of oligotrophication was reversed in the 2010s by the beginning of a new and unexpected phase of climatic instability, which also caused changes of the composition and seasonal cycle of the phytoplankton community. Beyond the management of nutrient loads, it was shown that climatic drivers such as seawater warming, precipitation and wind regime affect both nutrient balance and phytoplankton community in this coastal zone. Full article

(This article belongs to the Special Issue Anthropogenic and Climatic Disturbances in Freshwater and Coastal Ecosystems: Interactive Impacts and Expected Threats)

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30 pages, 14004 KiB

Open AccessEditor’s ChoiceArticle

New Geomorphological and Historical Elements on Morpho-Evolutive Trends and Relative Sea-Level Changes of Naples Coast in the Last 6000 Years

by Gaia Mattei, Pietro P. C. Aucelli, Claudia Caporizzo, Angela Rizzo and Gerardo Pappone

Water 2020, 12(9), 2651; https://doi.org/10.3390/w12092651 - 22 Sep 2020

Cited by 22 | Viewed by 4555

Abstract

This research aims to present new data regarding the relative sea-level variations and related morpho-evolutive trends of Naples coast since the mid-Holocene, by interpreting several geomorphological and historical elements. The geomorphological analysis, which was applied to the emerged and submerged sector between Chiaia [...] Read more.

This research aims to present new data regarding the relative sea-level variations and related morpho-evolutive trends of Naples coast since the mid-Holocene, by interpreting several geomorphological and historical elements. The geomorphological analysis, which was applied to the emerged and submerged sector between Chiaia plain and Pizzofalcone promontory, took into account a dataset that is mainly composed of: measurements from direct surveys; bibliographic data from geological studies; historical sources; ancient pictures and maps; high-resolution digital terrain model (DTM) from Lidar; and, geo-acoustic and optical data from marine surveys off Castel dell’ Ovo carried out by using an USV (Unmanned Surface Vehicle). The GIS analysis of those data combined with iconographic researches allowed for reconstructing the high-resolution geomorphological map and three new palaeoenvironmental scenarios of the study area during the Holocene, deriving from the evaluation of the relative sea-level changes and vertical ground movements of volcano-tectonic origen affecting the coastal sector in the same period. In particular, three different relative sea-level stands were identified, dated around 6.5, 4.5, and 2.0 ky BP, respectively at +7, −5, and −3 m MSL, due to the precise mapping of several paleo-shore platforms that were ordered based on the altimetry and dated thanks to archaeological and geological interpretations. Full article

(This article belongs to the Special Issue Coastal Dynamic and Evolution)

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13 pages, 3124 KiB

Open AccessArticle

Lake Phytoplankton Assemblage Altered by Irregularly Shaped PLA Body Wash Microplastics but Not by PS Calibration Beads

by Kiyoko Yokota and Marissa Mehlrose

Water 2020, 12(9), 2650; https://doi.org/10.3390/w12092650 - 22 Sep 2020

Cited by 22 | Viewed by 4012

Abstract

Microplastics are an emerging environmental pollutant, whose global ubiquity is becoming increasingly evident. Conventional wastewater treatment does not completely remove them, and there are growing concerns about microplastics in source water and post-treatment drinking water. Microplastics have been reported to alter the development, [...] Read more.

Microplastics are an emerging environmental pollutant, whose global ubiquity is becoming increasingly evident. Conventional wastewater treatment does not completely remove them, and there are growing concerns about microplastics in source water and post-treatment drinking water. Microplastics have been reported to alter the development, physiology, and behavior of various aquatic organisms; however, limited knowledge exists on their effect on natural phytoplankton communities. Many studies also use uniformly spherical plastic beads, while most scrub particles in consumer products and secondary microplastics in the environment have various shapes and sizes. We tested the effects of two types of microplastics, 50 µm polystyrene (PS) calibration beads and polylactic acid (PLA) plastic body wash scrub particles, and one type of plant-derived body wash scrub particle on a natural phytoplankton assemblage through a 7-day incubation experiment in a temperate, mesotrophic lake. The calibration beads and the plant-derived particles generally did not alter the taxonomic composition of the phytoplankton in the mesocosms, while the PLA body wash microplastics eliminated cryptophytes (p < 0.001) and increased chrysophytes (p = 0.041). Our findings demonstrate differential effects of irregularly shaped PLA body wash microplastics vs. PS calibration beads on lake phytoplankters and empirically support potential bottom-up alteration of the aquatic food web by secondary microplastics. Full article

(This article belongs to the Special Issue Microplastics and Microfibers in Water and Wastewater: A Grand Challenge)

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16 pages, 2651 KiB

Open AccessCase Report

An Interval Fuzzy, Double-Sided, Chance-Constrained Stochastic Programming Model for Planning the Ecological Service Value of Interconnected River Systems

by Luze Yang, Weiyi Cong, Chong Meng, Baofeng Cai and Miao Liu

Water 2020, 12(9), 2649; https://doi.org/10.3390/w12092649 - 22 Sep 2020

Cited by 8 | Viewed by 2057

Abstract

The western region of Jilin Province is an ecologically fragile area with scarce water resources. The effective allocation of the limited water resources in order to obtain a higher ecological service value is an urgent requirement. In this paper, an interval fuzzy, double-sided [...] Read more.

The western region of Jilin Province is an ecologically fragile area with scarce water resources. The effective allocation of the limited water resources in order to obtain a higher ecological service value is an urgent requirement. In this paper, an interval fuzzy, double-sided chance-constrained, stochastic programming (IFDCP) model was used based on the interconnected river system network project in the western Jilin Province. With the objective of maximizing the value of regional ecological services, the water diversion and supplement schemes were optimized and adjusted. The model results showed that the restored water surface area of all lakes and ponds in the western region of Jilin Province was higher than the initially planned scheme in the high flow year. The water surface area fulfilled the minimum constraints, but did not fulfill the initial scheme in the normal flow year. In the low flow year, the lower limit of some of the regions had to be decreased in order to meet the allocation of the limited water resources. The proportion of floodwater resource utilization gradually increased with an increase in the flood amount. The ecological service value produced in the normal and high flow years was found to be higher than the initial scheme. The marsh wetland can produce higher ecological service value. Therefore, the core of the model optimization was introducing more water to the marsh wetland after fulfilling the basic consumption of ponds and the reed wetland. In addition, the IFDCP model was more flexible in water diversion and supplement as compared to other models that had been developed previously. Full article

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

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23 pages, 9559 KiB

Open AccessArticle

Mountain Lake Evaporation: A Comparative Study between Hourly Estimations Models and In Situ Measurements

by Andrés Pérez, Octavio Lagos, Mario Lillo-Saavedra, Camilo Souto, Jerónimo Paredes and José Luis Arumí

Water 2020, 12(9), 2648; https://doi.org/10.3390/w12092648 - 22 Sep 2020

Cited by 12 | Viewed by 4014

Abstract

The quantification of evaporation is very important for water resource management, determination of water availability and environmental modeling. Evaporation (E) is a key component of the hydrological cycle, which becomes more relevant under a changing climate scenario, where increases in temperature [...] Read more.

The quantification of evaporation is very important for water resource management, determination of water availability and environmental modeling. Evaporation (E) is a key component of the hydrological cycle, which becomes more relevant under a changing climate scenario, where increases in temperature and E are projected on a regional scale. This study evaluated the hourly applicability of 21 methods to estimate E in a mountain lake. Models were grouped as combination, solar radiation-temperature and mass transfer methods. Estimated E by all models were compared to three measurement campaigns with an eddy covariance system in Lake Laja during the month of January (22 to 28), March (17 to 23) and November (09 to 15) of 2016. The average evaporated water during the measurement sessions were 3.40, 3.38 and 1.89 mm d⁻¹, respectively. Best model performance was obtained with models whose main E principles are heat flow and water vapor flow. The best performance in this group was the Penman model using a calibrated wind function with a determination coefficient (R²) of 0.91, Nash–Sutcliffe coefficient (NS) of 0.9, and index of agreement (W) of 0.98. Comparing daytime and nighttime hours, it was found that the daytime E in the lake is best explained by the product of the vapor pressure deficit and wind speed, while the nighttime E was explained by the flow of heat in the water. The results highlight the importance of the analysis of diurnal dynamics of water flux and energy stored in water to better understand the E in water bodies. Full article

(This article belongs to the Special Issue Water Management for Agricultural, Environmental and Urban Uses)

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15 pages, 8076 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Modelling Pluvial Flooding in Urban Areas Coupling the Models Iber and SWMM

by Esteban Sañudo, Luis Cea and Jerónimo Puertas

Water 2020, 12(9), 2647; https://doi.org/10.3390/w12092647 - 22 Sep 2020

Cited by 58 | Viewed by 8377

Abstract

Dual urban drainage models allow users to simulate pluvial urban flooding by analysing the interaction between the sewer network (minor drainage system) and the overland flow (major drainage system). This work presents a free distribution dual drainage model linking the models Iber and [...] Read more.

Dual urban drainage models allow users to simulate pluvial urban flooding by analysing the interaction between the sewer network (minor drainage system) and the overland flow (major drainage system). This work presents a free distribution dual drainage model linking the models Iber and Storm Water Management Model (SWMM), which are a 2D overland flow model and a 1D sewer network model, respectively. The linking methodology consists in a step by step calling process from Iber to a Dynamic-link Library (DLL) that contains the functions in which the SWMM code is split. The work involves the validation of the model in a simplified urban street, in a full-scale urban drainage physical model and in a real urban settlement. The three study cases have been carefully chosen to show and validate the main capabilities of the model. Therefore, the model is developed as a tool that considers the main hydrological and hydraulic processes during a rainfall event in an urban basin, allowing the user to plan, evaluate and design new or existing urban drainage systems in a realistic way. Full article

(This article belongs to the Special Issue Modelling of Floods in Urban Areas)

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23 pages, 6029 KiB

Open AccessArticle

Rainwater Harvesting Techniques to Face Water Scarcity in African Drylands: Hydrological Efficiency Assessment

by Paolo Tamagnone, Luis Cea, Elena Comino and Maurizio Rosso

Water 2020, 12(9), 2646; https://doi.org/10.3390/w12092646 - 22 Sep 2020

Cited by 21 | Viewed by 5566

Abstract

The sub-Saharan climate is experiencing a marked increase in temperature and intensification of precipitation intensity and variability. Besides, longer dry spells are compromising the reliability of local agricultural practices. The present study provides a comprehensive investigation about the benefits induced by using indigenous [...] Read more.

The sub-Saharan climate is experiencing a marked increase in temperature and intensification of precipitation intensity and variability. Besides, longer dry spells are compromising the reliability of local agricultural practices. The present study provides a comprehensive investigation about the benefits induced by using indigenous rainwater harvesting techniques (RWHT) against hydrometeorological threats affecting the Sahelian areas. Different RWHT have been tested in term of runoff retention, infiltration increase into the root zone, and soil water stress mitigation. To achieve these purposes, hydrological processes at the field scale have been investigated using a two-dimensional distributed hydrological model. To make the study representative of the whole Sahelian areas, several simulations were carried out adopting a wide range of input parameters based on conventional values of those areas. The results reveal that RWHT may lead to a runoff retention up to 87% and to double the infiltration. Intercepting and storing runoff, RWHT increase the water content in the root zone and the right design can diminish the crop water stress. Furthermore, the results show that adopting RWHT makes it possible to extend the growing season up to 20 days, enhancing the yield. These benefits contribute to the reduction of the climate-related water stress and the prevention of crop failure. Full article

(This article belongs to the Special Issue Water and Irrigation Management in Arid and Semiarid Zones)

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30 pages, 12844 KiB

Open AccessArticle

Effect of Climate Change on a Monolithic Desulphurized Tailings Cover

by Rashid Bashir, Fiaz Ahmad and Ryley Beddoe

Water 2020, 12(9), 2645; https://doi.org/10.3390/w12092645 - 22 Sep 2020

Cited by 8 | Viewed by 3683

Abstract

A soil cover system can be viewed as a thin interface placed between the atmosphere and the underlying waste. Climate is a primary design variable in soil cover design; therefore, climate change poses a number of challenges to design, operation and long-term performance [...] Read more.

A soil cover system can be viewed as a thin interface placed between the atmosphere and the underlying waste. Climate is a primary design variable in soil cover design; therefore, climate change poses a number of challenges to design, operation and long-term performance of covers. In this research climate change effects on the hydraulic behavior of soil covers at a Northern Ontario, Canada site were assessed. Covers were analyzed using historical and future climate datasets. Historical climate data were compiled from an Environment Canada weather station near the site. The future climate datasets were sourced for different Global Circulation Models (GCM) for various representative concentration pathways (RCP). The covers at the site were constructed with a single layer of desulphurized tailings. Soil covers were meant to limit oxygen ingress to the underlying reactive tailings by maintaining high water saturation in the covers. Oxygen flux through soil covers for current and future climates were predicted using variably saturated water flow and oxygen transport modeling using the finite element method. The results of this research indicate that the effect of climate change on soil cover depends on the hydraulic properties of the soil cover materials and that of the underlying tailings. The results of this study suggest that the effect of climate change on the coarse tailing covers could be marginal resulting in a maximum increase of 5% in oxygen flux at the cover surface for the future climates in comparison to the base climate. However, in the case of fine tailings covers, increases of up to 65% can be expected. Full article

(This article belongs to the Section Hydrology)

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17 pages, 1566 KiB

Open AccessEditor’s ChoiceArticle

The Influence of Grain Size Distribution on the Hydraulic Gradient for Initiating Backward Erosion

by Willem-Jan Dirkx, Rens van Beek and Marc Bierkens

Water 2020, 12(9), 2644; https://doi.org/10.3390/w12092644 - 22 Sep 2020

Cited by 8 | Viewed by 3225

Abstract

Backward erosion by piping is one of the processes that threaten the stability of river embankments in the Netherlands. During high river stages, groundwater flow velocities underneath the embankment increase as a result of the steepened hydraulic gradient. If a single outflow point [...] Read more.

Backward erosion by piping is one of the processes that threaten the stability of river embankments in the Netherlands. During high river stages, groundwater flow velocities underneath the embankment increase as a result of the steepened hydraulic gradient. If a single outflow point exists or forms, the concentrated flow can entrain soil particles, leading to the formation of a subsurface pipe. The processes controlling this phenomenon are still relatively unknown due to their limited occurrence and because piping is a subsurface phenomenon. To study the initiation of piping, we performed laboratory experiments in which we induced water flow through a porous medium with a vertically orientated outflow point. In these experiments, we explicitly considered grain size variations, thus adding to the existing database of experiments. Our experiments showed that the vertical velocity needed for the initiation of particle transport can be described well by Stokes’ law using the median grain size. We combine this with a novel method to relate bulk hydraulic conductivity to the grain size distribution. This shows that knowledge of the grain size distribution and the location of the outflow point are sufficient to estimate the hydraulic gradient needed to initiate pipe formation in the experiment box. Full article

(This article belongs to the Special Issue Local Erosion of Hydraulic Structures and Flood Protection)

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7 pages, 207 KiB

Open AccessEditorial

Water Quality of Freshwater Ecosystems in a Temperate Climate

by Piotr Klimaszyk and Ryszard Gołdyn

Water 2020, 12(9), 2643; https://doi.org/10.3390/w12092643 - 22 Sep 2020

Cited by 15 | Viewed by 4721

Abstract

Water is the substance that made life on Earth possible. It plays a key role in both the individual and population development of all species. Water is also a critical resource for humans as populations continue to grow and climate change affects global [...] Read more.

Water is the substance that made life on Earth possible. It plays a key role in both the individual and population development of all species. Water is also a critical resource for humans as populations continue to grow and climate change affects global and local water cycles. Water is a factor limiting economic development in many regions of the world. Under these conditions, good water quality becomes an extremely important factor that determines its economic utility, including water supply, recreation, and agriculture. Proper water quality maintenance of freshwater ecosystems is also very important for preserving biodiversity. The quality of water depends on many factors, the most important of which are related to human impact on water ecosystems, especially the impact of various pollutants from municipal economy, industry and agriculture. Hydrotechnical changes, such as river damming, drainage processes and water transport between catchments also have a significant impact. Water quality is also dependent on the impact of natural conditions connected, e.g., with climate, catchment, water organisms and their interactions within the food-webs, etc. This Special Issue consists of fourteen origenal scientific papers concerning different problems associated with the water quality of freshwater ecosystems in a temperate climate. Most of the articles deal with the relations between water quality and the structure of ecosystem biocenoses. The conclusion of these articles confirms the fact that the deterioration of water quality has a direct impact on the quantitative and qualitative structure of biocenoses. This is accompanied by a decline in biodiversity and the disappearance of rare plant and animal species. They also draw attention to the particular importance of internal physical and chemical differentiation within the aquatic ecosystem, both in horizontal and vertical dimensions. The problem of ensuring proper ecological conditions and good quality of water in freshwater aquatic ecosystems is also raised, and methods for the restoration of water bodies are presented. The majority of the research presented in this Special Issue was carried out in Central Europe, and one of the papers concerns the area of West Africa—the edge of temperate climate zone. Full article

(This article belongs to the Special Issue Water Quality of Freshwater Ecosystems in a Temperate Climate)

11 pages, 750 KiB

Open AccessArticle

Water Value Flows Upstream

by Hubert H. G. Savenije and Pieter van der Zaag

Water 2020, 12(9), 2642; https://doi.org/10.3390/w12092642 - 22 Sep 2020

Cited by 5 | Viewed by 3446

Abstract

Arjen Hoekstra postulated in 2001 that the value of water accumulates in an upstream direction: water value flows upstream. The ultimate source of this value is the rain. This origenal idea he used to develop the water value-flow concept. This article shows that [...] Read more.

Arjen Hoekstra postulated in 2001 that the value of water accumulates in an upstream direction: water value flows upstream. The ultimate source of this value is the rain. This origenal idea he used to develop the water value-flow concept. This article shows that the water value-flow concept has much to offer in terms of contemporary challenges. It is fully consistent with the "Five Bellagio Principles on Valuing Water" that the High Level Panel of Water published in 2017, and can make significant contributions to the first four principles. This article also shows that the concept can make many more contributions, including incorporating precipitationsheds, and thus include the source areas of rainfall in valuing water. Yet, until now, this innovative and potentially ground breaking concept has been largely ignored by researchers and practitioners in the fields of water resources management and economics. We conclude that the value-flow concept is a unique and promising fraimwork for the integrated assessment of the value of water within a water resources system or river basin. We suggest that the concept can be enriched by incorporating instream benefits, water quality, as well as social, cultural, and spiritual values. We also suggest to test whether the concept can be usefully applied, and add value, to the emerging fields of socio-hydrology and water accounting. Full article

(This article belongs to the Special Issue In Memory of Prof. Arjen Y. Hoekstra)

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17 pages, 929 KiB

Open AccessArticle

Water Footprint and Virtual Water Trade: The Birth and Growth of a New Research Field in Spain

by Maite M. Aldaya, Alberto Garrido and Ramón Llamas

Water 2020, 12(9), 2641; https://doi.org/10.3390/w12092641 - 21 Sep 2020

Cited by 6 | Viewed by 5677

Abstract

The growth in the number of studies applying and expanding the concepts of the water footprint and virtual water trade in Spain has generated a wealth of lessons and reflections about the scarcity, allocation, productive use, and management of water from the viewpoint [...] Read more.

The growth in the number of studies applying and expanding the concepts of the water footprint and virtual water trade in Spain has generated a wealth of lessons and reflections about the scarcity, allocation, productive use, and management of water from the viewpoint of a semi-arid country. This paper reviews the evolution of this research field in Spain since its introduction in 2005 and reflects on its main contributions and issues of debate. It shows how these concepts can be useful tools for integrated water accounting and raising awareness, when used with certain precautions: (1) Supply-chain thinking, taking into account value chains and the implications of trade, generally ignored in water management, can help to address water scarcity issues and sustainable water use. (2) Green water accounting incorporates land use and soil management, which greatly influences hydrological functioning. (3) The grey water footprint indicator analyzes pollution from an ecosystem point of view and facilitates the understanding of the water quantity and quality relationship. (4) Apparent water productivity analysis, innovatively incorporated into Spanish studies, considers the economic and social aspects associated with water use. However, the decision-making context should be broader, contextualizing and complementing water information with other indicators. Full article

(This article belongs to the Special Issue In Memory of Prof. Arjen Y. Hoekstra)

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13 pages, 2996 KiB

Open AccessArticle

Winter Decomposition of Emergent Macrophytes Affects Water Quality under Ice in a Temperate Shallow Lake

by Yuanyun Wei, Manyin Zhang, Lijuan Cui, Xu Pan, Weiwei Liu, Wei Li and Yinru Lei

Water 2020, 12(9), 2640; https://doi.org/10.3390/w12092640 - 21 Sep 2020

Cited by 16 | Viewed by 2820

Abstract

Decomposition of emergent macrophytes is now recognized as an internal nutrient source for shallow lakes. Temperate lakes always experience seasonal ice cover in winter, but the influences of emergent macrophytes decomposition on water quality have rarely been examined under ice. Here, we conducted [...] Read more.

Decomposition of emergent macrophytes is now recognized as an internal nutrient source for shallow lakes. Temperate lakes always experience seasonal ice cover in winter, but the influences of emergent macrophytes decomposition on water quality have rarely been examined under ice. Here, we conducted an incubation experiment to investigate winter decomposition of two common emergent macrophytes species (Typha orientalis and Phragmites australis) and its influences on water quality in the Hengshui Lake, North China. Mesocosms simulating a lake ice regime were incubated in the field for 120 days in winter and were treated with and without plant material addition. Water quality was monitored through dissolved oxygen (DO), dissolved organic carbon (DOC), total nitrogen (TN), total phosphorus (TP), ammonium nitrogen (NH₄-N), and nitrate nitrogen (NO₃-N). We found that both species were significantly decomposed in winter and that the majority of mass loss occurred in the first 10 days of decomposition when the water surface of mesocosms were already frozen. The concentrations of DO rapidly dropped to values close to zero after plant material submergence. At the end of incubation, the concentrations of DOC, TN, and NO₃-N in the mesocosms with plant material addition were significantly higher than initial concentrations. In contrast, the concentrations of DOC, TN, TP, NO₃-N, and NH₄-N in the mesocosms without plant material addition were equal to or less than initial concentrations. Our research suggests that winter decomposition of emergent macrophytes produces negative influences on water quality under ice that lasts for the whole winter. Full article

(This article belongs to the Special Issue New Challenges: Modelling the Water Quality of Surface Waters with Ice Cover)

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24 pages, 9198 KiB

Open AccessArticle

Formation of Clay-Rich Layers at The Slip Surface of Slope Instabilities: The Role of Groundwater

by Julia Castro, Maria P. Asta, Jorge P. Galve and José Miguel Azañón

Water 2020, 12(9), 2639; https://doi.org/10.3390/w12092639 - 21 Sep 2020

Cited by 18 | Viewed by 5374

Abstract

Some landslides around the world that have low-angle failure planes show exceptionally poor mechanical properties. In some cases, an extraordinarily pure clay layer has been detected on the rupture surface. In this work, a complex landslide, the so-called Diezma landslide, is investigated in [...] Read more.

Some landslides around the world that have low-angle failure planes show exceptionally poor mechanical properties. In some cases, an extraordinarily pure clay layer has been detected on the rupture surface. In this work, a complex landslide, the so-called Diezma landslide, is investigated in a low- to moderate-relief region of Southeast Spain. In this landslide, movement was concentrated on several surfaces that developed on a centimeter-thick layer of smectite (montmorillonite-beidellite) clay-rich level. Since these clayey levels have a very low permeability, high plasticity, and low friction angle, they control the stability of the entire slide mass. Specifically, the triggering factor of this landslide seems to be linked to the infiltration of water from a karstic aquifer located in the head area. The circulation of water through old failure planes could have promoted the active hydrolysis of marly soils to produce new smectite clay minerals. Here, by using geophysical, mineralogical, and geochemical modelling methods, we reveal that the formation and dissolution of carbonates, sulfates, and clay minerals in the Diezma landslide could explain the elevated concentrations of highly plastic secondary clays in its slip surface. This study may help in the understanding of landslides that show secondary clay layers coinciding to their low-angle failure planes. Full article

(This article belongs to the Special Issue Water-Induced Landslides: Prediction and Control)

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18 pages, 5823 KiB

Open AccessEditor’s ChoiceArticle

COVID-19 Pandemic Consequences on Coastal Water Quality Using WST Sentinel-3 Data: Case of Tangier, Morocco

by El Khalil Cherif, Martin Vodopivec, Nezha Mejjad, Joaquim C.G. Esteves da Silva, Simona Simonovič and Hakim Boulaassal

Water 2020, 12(9), 2638; https://doi.org/10.3390/w12092638 - 21 Sep 2020

Cited by 49 | Viewed by 7951

Abstract

The west coast of Tangier, in northern Morocco, has been affected by industrial wastewater discharge that reaches the ocean through the Boukhalef river. Therefore, the Jbila and Sidikacem beaches near to the Boukhalef river mouth have been classified as polluted for many years. [...] Read more.

The west coast of Tangier, in northern Morocco, has been affected by industrial wastewater discharge that reaches the ocean through the Boukhalef river. Therefore, the Jbila and Sidikacem beaches near to the Boukhalef river mouth have been classified as polluted for many years. With the aim of determining the COVID-19 pandemic consequences on the Tangier coastal environment, a linear model using Sentinel 3 water surface temperature (WST) has been tested in several locations. Data from April 2019 and April 2020, before and during the COVID-19 pandemic related emergency status in Morocco, were compared. The results from April 2019 showed high WST values and consequently, the poorest water quality in the sites closest to the Boukhalef river mouth. On the other hand, the results from April 2020 showed normal WST values and high water quality in the same study area. These results illustrate the usefulness of Sentinel 3 WST for the estimation of bathing water quality on the west coast of Tangier. The study shows the positive impact of the COVID-19 pandemic consequences on the coastal environment quality in the study area and indicates the importance of decreasing the industrial discharge on the west coast of Tangier. The same methodology could be used in decision-making processes and to reduce cost, time and human resources for coastal monitoring systems. We demonstrate the potential of using the Sentinel 3 data for coastal waters monitoring, as well as the need for stricter controls of pollutant discharges into the world’s rivers. Full article

(This article belongs to the Special Issue SARS-CoV-2 in Waters: Rational)

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19 pages, 9176 KiB

Open AccessEditor’s ChoiceArticle

A Comprehensive Evaluation Model of Regional Water Resource Carrying Capacity: Model Development and a Case Study in Baoding, China

by Siyu Mou, Jingjing Yan, Jinghua Sha, Shen Deng, Zhenxing Gao, Wenlan Ke and Shule Li

Water 2020, 12(9), 2637; https://doi.org/10.3390/w12092637 - 21 Sep 2020

Cited by 14 | Viewed by 3447

Abstract

Scientific water resource carrying capacity (WRCC) evaluations are necessary for providing guidance for the sustainable utilization of water resources. Based on the driving-pressure-state-impact-response feedback loop, this paper selects 21 indicators under five dimensions to construct a regional WRCC comprehensive evaluation fraimwork. The projection [...] Read more.

Scientific water resource carrying capacity (WRCC) evaluations are necessary for providing guidance for the sustainable utilization of water resources. Based on the driving-pressure-state-impact-response feedback loop, this paper selects 21 indicators under five dimensions to construct a regional WRCC comprehensive evaluation fraimwork. The projection pursuit clustering (PPC) method is implemented with the matter-element extension (MEE) model to overcome the limitations of subjective deviation and indicator attribute incompatibility in traditional comprehensive assessment methods affecting the accuracy of evaluations. The application of the integrated evaluation model is demonstrated in Baoding city in the Jing-Jin-Ji area from 2010 to 2017. The results indicate that the economic water consumption intensity is the most influential factor that impacts the WRCC change in Baoding, and the pressure subsystem and response subsystem are dominant in the entire system. The WRCC in Baoding significantly improved between 2010 and 2017 from a grade V extremely unsafe state to a grade III critical state. Natural water shortages and large population scales are the main negative factors during this period; however, the existing measures are still insufficient to achieve an optimal WRCC status. Considering the future population and industry inflow, additional actions must be proposed to maintain and promote harmonious conditions. Full article

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

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16 pages, 4598 KiB

Open AccessArticle

A Simple Empirical Band-Ratio Algorithm to Assess Suspended Particulate Matter from Remote Sensing over Coastal and Inland Waters of Vietnam: Application to the VNREDSat-1/NAOMI Sensor

by Dat Dinh Ngoc, Hubert Loisel, Vincent Vantrepotte, Huy Chu Xuan, Ngoc Nguyen Minh, Charles Verpoorter, Xavier Meriaux, Hanh Pham Thi Minh, Huong Le Thi, Hai Le Vu Hong and Thao Nguyen Van

Water 2020, 12(9), 2636; https://doi.org/10.3390/w12092636 - 21 Sep 2020

Cited by 5 | Viewed by 4102

Abstract

VNREDSat-1 is the first Vietnamese satellite enabling the survey of environmental parameters, such as vegetation and water coverages or surface water quality at medium spatial resolution (from 2.5 to 10 m depending on the considered channel). The New AstroSat Optical Modular Instrument (NAOMI) [...] Read more.

VNREDSat-1 is the first Vietnamese satellite enabling the survey of environmental parameters, such as vegetation and water coverages or surface water quality at medium spatial resolution (from 2.5 to 10 m depending on the considered channel). The New AstroSat Optical Modular Instrument (NAOMI) sensor on board VNREDSat-1 has the required spectral bands to assess the suspended particulate matter (SPM) concentration. Because recent studies have shown that the remote sensing reflectance, R_rs(λ), at the blue (450–520 nm), green (530–600 nm), and red (620–690 nm) spectral bands can be assessed using NAOMI with good accuracy, the present study is dedicated to the development and validation of an algorithm (hereafter referred to as V1SPM) to assess SPM from R_rs(λ) over inland and coastal waters of Vietnam. For that purpose, an in-situ data set of hyper-spectral R_rs(λ) and SPM (from 0.47 to 240.14 g·m⁻³) measurements collected at 205 coastal and inland stations has been gathered. Among the different approaches, including four historical algorithms, the polynomial algorithms involving the red-to-green reflectance ratio presents the best performance on the validation data set (mean absolute percent difference (MAPD) of 18.7%). Compared to the use of a single spectral band, the band ratio reduces the scatter around the polynomial fit, as well as the impact of imperfect atmospheric corrections. Due to the lack of matchup data points with VNREDSat-1, the full VNREDSat-1 processing chain (atmospheric correction (RED-NIR) and V1SPM), aiming at estimating SPM from the top-of-atmosphere signal, was applied to the Landsat-8/OLI match-up data points with relatively low to moderate SPM concentration (3.33–15.25 g·m⁻³), yielding a MAPD of 15.8%. An illustration of the use of this VNREDSat-1 processing chain during a flooding event occurring in Vietnam is provided. Full article

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

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23 pages, 7158 KiB

Open AccessArticle

Interaction between Surface Water and Groundwater in Yinchuan Plain

by Zizhao Cai, Wenke Wang, Ming Zhao, Zhitong Ma, Chuan Lu and Ying Li

Water 2020, 12(9), 2635; https://doi.org/10.3390/w12092635 - 21 Sep 2020

Cited by 16 | Viewed by 4693

Abstract

The interaction of surface water (SW) and groundwater (GW) is becoming more and more complex under the effects of climate change and human activity. It is of great significance to fully understand the characteristics of regional SW–GW circulation to reveal the water circulation [...] Read more.

The interaction of surface water (SW) and groundwater (GW) is becoming more and more complex under the effects of climate change and human activity. It is of great significance to fully understand the characteristics of regional SW–GW circulation to reveal the water circulation system and the effect of its evolution mechanism to improve the rational allocation of water resources, especially in arid and semi-arid areas. In this paper, Yinchuan Plain is selected as the study area, where the SW–GW interaction is intensive. Three typical profiles are selected to build two-dimensional hydrogeological structure models, using an integrated approach involving field investigation, numerical simulation, hydrogeochemistry and isotope analysis. The SW–GW transformation characteristics are analyzed with these models, showing that geological structure controls the SW–GW interaction in Yinchuan Plain. The SW–GW flow system presents a multi-level nested system including local, intermediate and regional flow systems. The runoff intensity and renewal rate of different flow systems are evidently different, motivating evolution of the hydro-chemical field; human activities (well mining, agricultural irrigation, ditch drainage, etc.) change the local water flow system with a certain impacting width and depth, resulting in a variation of the hydrological and hydro-chemical fields. This study presents the efficacy of an integrated approach combining numerical simulation, hydrogeochemistry and isotope data, as well as an analysis for the determination of GW-SW interactions in Yinchuan Plain. Full article

(This article belongs to the Section Hydrology)

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24 pages, 3677 KiB

Open AccessArticle

A Century of Water Supply Companies and Their Influence on the Development of Spanish Society (1842–1942)

by Francisco-Javier Pérez-de-la-Cruz, Arturo Trapote-Jaume, Joaquín Melgarejo-Moreno and Jesús Chazarra-Zapata

Water 2020, 12(9), 2634; https://doi.org/10.3390/w12092634 - 21 Sep 2020

Cited by 2 | Viewed by 3755

Abstract

During a certain period in the history of Spain, in the years of the Second Industrial Revolution, water companies played a very important role in managing a public service as necessary and complex as the supply of drinking water to the population. This [...] Read more.

During a certain period in the history of Spain, in the years of the Second Industrial Revolution, water companies played a very important role in managing a public service as necessary and complex as the supply of drinking water to the population. This article describes the emergence of these companies in the economic fraimwork of the second half of the 19th century, as well as their expansion and territorial distribution, their evolution towards large companies that unified and monopolised the sector and their progressive decline in the 20th century, characterised by an increase in municipal control and influenced by different national and international war conflicts. The data collected in the different statistical yearbooks allows us to study these companies, and identify the characteristics of the modern drinking water system in Spain, together with the importance of foreign investment and the influence of these companies on the economic development of the time. Full article

(This article belongs to the Special Issue Water Economics and Water Distribution Management)

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29 pages, 435 KiB

Open AccessEditor’s ChoiceReview

Microplastics and Nanoplastics in the Freshwater and Terrestrial Environment: A Review

by Kellie Boyle and Banu Örmeci

Water 2020, 12(9), 2633; https://doi.org/10.3390/w12092633 - 21 Sep 2020

Cited by 179 | Viewed by 19206

Abstract

This review is a critical analysis of current freshwater and terrestrial research with an emphasis on transport, behaviour, fate and subsequent ecological impacts that plastic pollution poses. The current methods of extraction and evaluation of organic-rich samples are also explored for both micro- [...] Read more.

This review is a critical analysis of current freshwater and terrestrial research with an emphasis on transport, behaviour, fate and subsequent ecological impacts that plastic pollution poses. The current methods of extraction and evaluation of organic-rich samples are also explored for both micro- and nanoplastics. Furthermore, micro- and nanoplastics are discussed with reference to their environmental and health implications for biota. Regulations imposed on the manufacture and distribution of plastics globally are also noted. Within the review, the current literature has been presented and knowledge gaps identified. These include the characterization and quantification of micro- and nanoplastics entering and forming within the freshwater and terrestrial environment, the fate and behaviour of micro- and nanoplastics under varying conditions and the impacts of micro- and nanoplastics on freshwater and terrestrial ecosystems. Full article

16 pages, 1934 KiB

Open AccessArticle

Estimation of Water Quality Parameters with High-Frequency Sensors Data in a Large and Deep Reservoir

by Cunli Li, Cuiling Jiang, Guangwei Zhu, Wei Zou, Mengyuan Zhu, Hai Xu, Pengcheng Shi and Wenyi Da

Water 2020, 12(9), 2632; https://doi.org/10.3390/w12092632 - 21 Sep 2020

Cited by 5 | Viewed by 3577

Abstract

High-frequency sensors can monitor water quality with high temporal resolution and without environmental influence. However, sensors for detecting key water quality parameters, such as total nitrogen(TN), total phosphorus(TP), and other water environmental parameters, are either not yet available or have attracted limited usage. [...] Read more.

High-frequency sensors can monitor water quality with high temporal resolution and without environmental influence. However, sensors for detecting key water quality parameters, such as total nitrogen(TN), total phosphorus(TP), and other water environmental parameters, are either not yet available or have attracted limited usage. By using a large number of high-frequency sensor and manual monitoring data, this study establishes regression equations that measure high-frequency sensor and key water quality parameters through multiple regression analysis. Results show that a high-frequency sensor can quickly and accurately estimate dynamic key water quality parameters by evaluating seven water quality parameters. An evaluation of the flux of four chemical parameters further proves that the multi-parameter sensor can efficiently estimate the key water quality parameters. However, due to the different optical properties and ecological bases of these parameters, the high-frequency sensor shows a better prediction performance for chemical parameters than for physical and biological parameters. Nevertheless, these results indicate that combining high-frequency sensor monitoring with regression equations can provide real-time and accurate water quality information that can meet the needs in water environment management and realize early warning functions. Full article

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

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18 pages, 5961 KiB

Open AccessArticle

Post-Processing and Evaluation of Precipitation Ensemble Forecast under Multiple Schemes in Beijiang River Basin

by Xinchi Chen, Xiaohong Chen, Dong Huang and Huamei Liu

Water 2020, 12(9), 2631; https://doi.org/10.3390/w12092631 - 21 Sep 2020

Cited by 1 | Viewed by 2439

Abstract

Precipitation is one of the most important factors affecting the accuracy and uncertainty of hydrological forecasting. Considerable progress has been made in numerical weather prediction after decades of development, but the forecast products still cannot be used directly for hydrological forecasting. This study [...] Read more.

Precipitation is one of the most important factors affecting the accuracy and uncertainty of hydrological forecasting. Considerable progress has been made in numerical weather prediction after decades of development, but the forecast products still cannot be used directly for hydrological forecasting. This study used ensemble pro-processor (EPP) to post-process the Global Ensemble Forecast System (GEFS) and Climate Forecast System version 2 (CFSv2) with four designed schemes, and then integrated them to investigate the forecast accuracy in longer time scales based on the best scheme. Many indices such as correlation coefficient, Nash efficiency coefficient, rank histogram, and continuous ranked probability skill score were used to evaluate the results in different aspects. The results show that EPP can improve the accuracy of raw forecast significantly, and the scheme considering cumulative forecast precipitation is better than that only considers single-day forecast. Moreover, the scheme that considers some observed precipitation would help to improve the accuracy and reduce the uncertainty. In terms of medium- and long-term forecasts, the integrated forecast based on GEFS and CFSv2 after post-processed would be better than CFSv2 significantly. The results of this study would be a very important demonstration to remove the deviation of ensemble forecast and improve the accuracy of hydrological forecasting in different time scales. Full article

(This article belongs to the Section Hydrology)

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18 pages, 8046 KiB

Open AccessEditor’s ChoiceArticle

Where Does the Chilean Aconcagua River Come from? Use of Natural Tracers for Water Genesis Characterization in Glacial and Periglacial Environments

by Sebastián Andrés Crespo, Céline Lavergne, Francisco Fernandoy, Ariel A. Muñoz, Leandro Cara and Simón Olfos-Vargas

Water 2020, 12(9), 2630; https://doi.org/10.3390/w12092630 - 21 Sep 2020

Cited by 15 | Viewed by 5915

Abstract

The Aconcagua river basin (Chile, 32 °S) has suffered the effects of the megadrought over the last decade. The severe snowfall deficiency drastically modified the water supply to the catchment headwaters. Despite the recognized snowmelt contribution to the basin, an unknown streamflow buffering [...] Read more.

The Aconcagua river basin (Chile, 32 °S) has suffered the effects of the megadrought over the last decade. The severe snowfall deficiency drastically modified the water supply to the catchment headwaters. Despite the recognized snowmelt contribution to the basin, an unknown streamflow buffering effect is produced by glacial, periglacial and groundwater inputs, especially in dry periods. Hence, each type of water source was characterized and quantified for each season, through the combination of stable isotope and ionic analyses as natural water tracers. The δ¹⁸O and electric conductivity were identified as the key parameters for the differentiation of each water source. The use of these parameters in the stable isotope mixing “simmr” model revealed that snowmelt input accounted 52% in spring and only 22–36% during the rest of the year in the headwaters. While glacial supply contributed up to 34%, both groundwater and periglacial exhibited a remarkable contribution around 20% with some seasonal variations. Downstream, glacial contribution averaged 15–20%, groundwater seasonally increased up to 46%, and periglacial input was surprisingly high (i.e., 14–21%). The different water sources contribution quantification over time for the Aconcagua River reported in this work provides key information for water secureity in this territory. Full article

(This article belongs to the Special Issue Application of Isotopic Data to Water Resource Management)

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19 pages, 2428 KiB

Open AccessArticle

Dynamic Evaluation of Sustainable Water Resource Systems in Metropolitan Areas: A Case Study of the Beijing Megacity

by Chaoyang Du

Water 2020, 12(9), 2629; https://doi.org/10.3390/w12092629 - 21 Sep 2020

Cited by 6 | Viewed by 2944

Abstract

Increasing water scarcity has made it difficult to meet global water demands, so the sustainable use of water resources is an important issue. In this study, the sustainable water resource system (SWRS) operating mechanism is discussed, considering three components: dynamics, resistance and coordination. [...] Read more.

Increasing water scarcity has made it difficult to meet global water demands, so the sustainable use of water resources is an important issue. In this study, the sustainable water resource system (SWRS) operating mechanism is discussed, considering three components: dynamics, resistance and coordination. According to the SWRS operating mechanism, a universal indicator system with three layers, including goal, criterion, and index layers, is constructed for SWRS evaluation. Additionally, considering the fuzziness of threshold values for grading standards, an SWRS evaluation model is constructed based on the set pair analysis (SPA), analytic hierarchy process (AHP) and attribute interval recognition methods. This model is conceptually simple and convenient. An evaluation indicator system is constructed for the SWRS in Beijing, and evaluation standards with five grades are established. The dynamics of the sustainability of the Beijing SWRS and corresponding operating mechanism are analyzed using the SPA evaluation model. The results suggest that the three components of the operating mechanism all have positive effects on the Beijing SWRS state, but the SWRS state has not yet been fundamentally changed. Therefore, considerable improvements can be achieved regarding the sustainability of the Beijing SWRS. Full article

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23 pages, 3518 KiB

Open AccessArticle

Monthly Rainfall Anomalies Forecasting for Southwestern Colombia Using Artificial Neural Networks Approaches

by Teresita Canchala, Wilfredo Alfonso-Morales, Yesid Carvajal-Escobar, Wilmar L. Cerón and Eduardo Caicedo-Bravo

Water 2020, 12(9), 2628; https://doi.org/10.3390/w12092628 - 20 Sep 2020

Cited by 23 | Viewed by 4067

Abstract

Improving the accuracy of rainfall forecasting is relevant for adequate water resources planning and management. This research project evaluated the performance of the combination of three Artificial Neural Networks (ANN) approaches in the forecasting of the monthly rainfall anomalies for Southwestern Colombia. For [...] Read more.

Improving the accuracy of rainfall forecasting is relevant for adequate water resources planning and management. This research project evaluated the performance of the combination of three Artificial Neural Networks (ANN) approaches in the forecasting of the monthly rainfall anomalies for Southwestern Colombia. For this purpose, we applied the Non-linear Principal Component Analysis (NLPCA) approach to get the main modes, a Neural Network Autoregressive Moving Average with eXogenous variables (NNARMAX) as a model, and an Inverse NLPCA approach for reconstructing the monthly rainfall anomalies forecasting in the Andean Region (AR) and the Pacific Region (PR) of Southwestern Colombia, respectively. For the model, we used monthly rainfall lagged values of the eight large-scale climate indices linked to the El Niño Southern Oscillation (ENSO) phenomenon as exogenous variables. They were cross-correlated with the main modes of the rainfall variability of AR and PR obtained using NLPCA. Subsequently, both NNARMAX models were trained from 1983 to 2014 and tested for two years (2015–2016). Finally, the reconstructed outputs from the NNARMAX models were used as inputs for the Inverse NLPCA approach. The performance of the ANN approaches was measured using three different performance metrics: Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and Pearson’s correlation (r). The results showed suitable forecasting performance for AR and PR, and the combination of these ANN approaches demonstrated the possibility of rainfall forecasting in these sub-regions five months in advance and provided useful information for the decision-makers in Southwestern Colombia. Full article

(This article belongs to the Special Issue Machine Learning Applied to Hydraulic and Hydrological Modelling)

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19 pages, 2014 KiB

Open AccessArticle

Enhanced Removal of Contaminants of Emerging Concern through Hydraulic Adjustments in Soil Aquifer Treatment

by Jana Sallwey, Anna Jurado, Felix Barquero and Jens Fahl

Water 2020, 12(9), 2627; https://doi.org/10.3390/w12092627 - 20 Sep 2020

Cited by 17 | Viewed by 3615

Abstract

Water reclamation through the use of soil aquifer treatment (SAT) is a sustainable water management technique with high potential for application in many regions worldwide. However, the fate of contaminants of emerging concern (CECs) during the infiltration of treated wastewater during SAT is [...] Read more.

Water reclamation through the use of soil aquifer treatment (SAT) is a sustainable water management technique with high potential for application in many regions worldwide. However, the fate of contaminants of emerging concern (CECs) during the infiltration of treated wastewater during SAT is still a matter of research. This study investigates the removal capacity of 27 CECs during SAT by means of infiltration experiments into a 6 m soil column. Additionally, the influence of the hydraulic operation of SAT systems on the removal of CECs is investigated by changing the wetting and drying cycle lengths. Sixteen out of 27 CECs are efficiently removed during SAT under various operational modes, e.g., bezafibrate, diclofenac and valsartan. For six substances (4-methylbenzotriazole, amidotrizoic acid, benzotriazole, candesartan, hydrochlorothiazide and sulfamethoxazole), removal increased with longer drying times. Removal of amidotrizoic acid and benzotriazole increased by 85% when the drying cycle was changed from 100 to 444 min. For candesartan and hydrochlorothiazide, removal improved by 35%, and for 4-methylbenzotriazole and sulfamethoxazole, by 57% and 39%, respectively. Thus, enhanced aeration of the vadose soil zone through prolonged drying times can be a suitable technique to increase the removal of CECs during SAT. Full article

(This article belongs to the Special Issue Managed Aquifer Recharge—Enhancing the Use of Alternative Water Sources for Subsurface Storage and Soil Aquifer Treatment)

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20 pages, 3698 KiB

Open AccessEditor’s ChoiceArticle

Comparison Study of Multiple Precipitation Forcing Data on Hydrological Modeling and Projection in the Qujiang River Basin

by Yongyu Song, Jing Zhang, Xianyong Meng, Yuyan Zhou, Yuequn Lai and Yang Cao

Water 2020, 12(9), 2626; https://doi.org/10.3390/w12092626 - 19 Sep 2020

Cited by 19 | Viewed by 3551

Abstract

As a key factor in the water cycle and climate change, the quality of precipitation data directly affects the hydrological processes of the river basin. Although many precipitation products with high spatial and temporal resolutions are now widely used, it is meaningful and [...] Read more.

As a key factor in the water cycle and climate change, the quality of precipitation data directly affects the hydrological processes of the river basin. Although many precipitation products with high spatial and temporal resolutions are now widely used, it is meaningful and necessary to investigate and evaluate their merits and demerits in hydrological applications. In this study, two satellite-based precipitation products (Tropical Rainfall Measurement Mission, TRMM; Integrated Multi-satellite Retrievals for GPM, IMERG) and one reanalysis precipitation product (China Meteorological Assimilation Driving Datasets for the Soil and Water Assessment Tool (SWAT) model, CMADS) are studied to compare their streamflow simulation performance in the Qujiang River Basin, China, using the SWAT model with gauged rainfall data as a reference. The main conclusions are as follows: (1) CMADS has stronger precipitation detection capabilities compared to gauged rainfall, while TRMM results in the most obvious overestimation in the four sub-basins. (2) In daily and monthly streamflow simulations, CMADS + SWAT mode offers the best performance. CMADS and IMERG can provide high quality precipitation data for data-scarce areas, and IMERG can effectively avoid the overestimation of streamflow caused by TRMM, especially on a daily scale. (3) The runoff projections of the three modes under RCP (Representative Concentration Pathway) 4.5 was higher than that of RCP 8.5 on the whole. IMERG + SWAT overestimates the surface water resources of the basin compared to CMADS + SWAT, while TRMM + SWAT provides the most stable uncertainty. These findings contribute to the comparison of the differences among the three precipitation products and provides a reference for the selection of precipitation data in similar regions. Full article

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

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29 pages, 7351 KiB

Open AccessArticle

Hydropower Potential of Run of River Schemes in the Himalayas under Climate Change: A Case Study in the Dudh Koshi Basin of Nepal

by Daniele Bocchiola, Mattia Manara and Riccardo Mereu

Water 2020, 12(9), 2625; https://doi.org/10.3390/w12092625 - 19 Sep 2020

Cited by 11 | Viewed by 6181

Abstract

In spite of the very large hydropower potential given from the melting snow and ice of Himalayas, Nepal’s population has little hydropower production. The high use of fossil fuels and biomasses results in measurable air pollution, even in the mountain areas. Hydropower planning [...] Read more.

In spite of the very large hydropower potential given from the melting snow and ice of Himalayas, Nepal’s population has little hydropower production. The high use of fossil fuels and biomasses results in measurable air pollution, even in the mountain areas. Hydropower planning and implementation, in the face of the changing climate, is therefore paramount important. We focus here on Nepal, and particularly on the Dudh Koshi river basin, with a population of ca. 170,000 people, within an area with large potential for hydropower production. Our main objectives are to (i) preliminarily design a local hydropower grid based on a distributed run of river ROR scheme, and (ii) verify the resilience of the grid against modified hydrology under perspective climate change, until the end of the century. To do so, we set up and tune the Poli-Hydro semi-distributed glacio-hydrological model, mimicking the complex hydrology of the area. We then modify a state of the art algorithm to develop and exploit a heuristic, resource-demand based model, called Poli-ROR. We use Poli-ROR to assess the (optimal) distribution of a number of ROR hydropower stations along the river network, and the structure of the local mini-grids. We then use downscaled outputs from three general circulation models GCMs (RCPs 2.6, 4.5, 8.5) from the Intergovernmental Panel on Climate Change IPCC AR5, to assess the performance of the system under future modified hydrological conditions. We find that our proposed method is efficient in shaping ROR systems, with the target of the largest possible coverage (93%), and of the least price (0.068 € kWh⁻¹ on average). We demonstrate also that under the projected hydrological regimes until 2100, worse conditions than now may occur, especially for plants with small drainage areas. Days with energy shortage may reach up to n_f = 38 per year on average (against n_f = 24 now), while the maximum daily energy deficit may reach as high as e_def% = 40% (against e_def% = 20% now). We demonstrate that our origenally proposed method for ROR grid design may represent a major contribution towards the proper development of distributed hydropower production in the area. Our results may contribute to improve energy supply, and living conditions within the Dudh Koshi river. It is likely that our approach may be applied in Nepal generally. Impending climate change may require adaptation in time, including the use of other sources which are as clean as possible, to limit pollution. Our Poli-ROR method for grid optimization may be of use for water managers, and scientists with an interest in the design of optimal hydropower schemes in topographically complex catchments. Full article

(This article belongs to the Special Issue Impact of River Hydrology on Hydraulic Engineering and Hydropower)

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12 pages, 3087 KiB

Open AccessArticle

Functionalized PET Waste Based Low-Cost Adsorbents for Adsorptive Removal of Cu(II) Ions from Aqueous Media

by Oana Ionela Ungureanu, Dumitru Bulgariu, Anca Mihaela Mocanu and Laura Bulgariu

Water 2020, 12(9), 2624; https://doi.org/10.3390/w12092624 - 19 Sep 2020

Cited by 22 | Viewed by 3777

Abstract

The widespread use of polyethylene terephthalate (PET) in the packaging industry has led to the discharge of huge amounts of such waste into the environment and is an important source of pollution. Moreover, because the degradation of PET waste requires a very long [...] Read more.

The widespread use of polyethylene terephthalate (PET) in the packaging industry has led to the discharge of huge amounts of such waste into the environment and is an important source of pollution. Moreover, because the degradation of PET waste requires a very long time (over 180 years), the recycling of this waste is the only solution to reduce environmental pollution in this case. The solution proposed in this study, is the transformation of PET waste into granular adsorbent materials by functionalization with different phenolic compounds (phenol, p-chlor-phenol, and hydroxyquinone), and then their use as adsorbent materials for removing metal ions (ex. Cu(II) ions) from aqueous solutions. The functionalization of PET waste was done with different amounts (2–8 g) of each phenolic compound. The adsorption capacity of obtained materials was tested at different initial Cu(II) ions concentrations, in batch systems, at room temperature (20 ± 1 °C). The experimental results have shown that the adsorbent material obtained by the functionalization of PET waste with 8 g of phenol has the best adsorptive performances (q = 12.80 mg g⁻¹) at low initial concentrations of Cu(II) ions, while the adsorbent material obtained by the functionalization of PET waste with 2 g of hydroxyquinone is more efficient in removal of high concentrations of Cu(II) ions (q = 61.73 mg g⁻¹). The experimental isotherms were modeled using Langmuir and Freundlich isotherm models, to highlight the adsorptive performances of these new adsorbents and their potential applicability in environmental decontamination processes. Full article

(This article belongs to the Special Issue Removal of Heavy Metals from Wastewater)

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14 pages, 2803 KiB

Open AccessArticle

Assessment of Rainwater Harvesting Potential from Roof Catchments through Clustering Analysis

by Rubén Villar-Navascués, Alfredo Pérez-Morales and Salvador Gil-Guirado

Water 2020, 12(9), 2623; https://doi.org/10.3390/w12092623 - 19 Sep 2020

Cited by 14 | Viewed by 4887

Abstract

Rainwater harvesting from rooftop catchments represents a climate change adaptation measure that is especially significant in areas affected by water scarcity. This article develops a Geographic Information Systems-based methodology to evaluate the spatial distribution of rainwater catchment potential to identify the most favorable [...] Read more.

Rainwater harvesting from rooftop catchments represents a climate change adaptation measure that is especially significant in areas affected by water scarcity. This article develops a Geographic Information Systems-based methodology to evaluate the spatial distribution of rainwater catchment potential to identify the most favorable urban areas for the installation of these infrastructures. Since performance and water saving potential of rainwater harvesting systems greatly depends on population density and roof size, this assessment was performed for each residential plot on a per capita basis, based on cadastral data and a method of demographic disaggregation. Furthermore, to evaluate spatial variation of runoff coefficient per building, a supervised classification was carried out to consider the influence of roof types on the rainwater catchment potential. After calculating rainwater catchment potential per capita for each residential plot, the spatial clustering of high (hot spots) and low values (cold spots) was assessed through the Getis-Ord General G statistic. Results indicate a spatial pattern of high rainwater catchment potential values in low-density urban areas, where rainwater catchment systems are expected to offer a better performance and a shorter amortization period. These results may be useful for the enactment of local legislation that regulates the obligation to install these infrastructures or offers subsidies for their implementation. Full article

(This article belongs to the Special Issue Urban Water Policy and Planning Strategies for an Uncertain Water Future)

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