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Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability

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A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Water Resources Management, Policy and Governance".

Deadline for manuscript submissions: closed (28 February 2022) | Viewed by 47771

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Special Issue Editors

Dr. Maurizio Polemio

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Guest Editor

Italian National Research Council-Research Institute for Geo-Hydrological Protection (CNR-IRPI), Via Amendola 122/I, 70126 Bari, Italy
Interests: groundwater management; seawater intrusion; groundwater monitoring
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Konstantinos Voudouris

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Guest Editor

Laboratory of Engineering Geology & Hydrogeology, Department of Geology, Faculty of Sciences, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
Interests: groundwater management; water quality; seawater intrusion; simulation of water flow; aquifer vulnerability
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The prospect of a word population of 9 billion by 2050, growing urbanisation, intensive irrigated agriculture and climate change will add extra pressures on the water resources and the environment. The availability of high-quality freshwater is a decisive factor for socio-economic development. Water scarcity occurs in many countries—particularly in the Mediterranean, Middle East, Africa, etc.—that are confronted with a crucial combination of a severe lack of and increasing demand for high-quality water. World water resources seem abundant; however, only 0.7% of this total amount is usable water. Serious water pollution problems make 1/5 of the world’s population (approximately 1.1 billion people) at risk of water-related diseases. Competition for water made scarce by intensive irrigation is already a major source of conflict in arid and semiarid areas.

Groundwater is worldwide the main source of domestic supply and irrigation. As a result, there is a widespread established negative water balance, which is highly problematic in the case of coastal aquifer systems which are at risk of salinification due to seawater intrusion.

Pressures on groundwater arise from pollution sources; this is a serious problem due to the use of chemicals in agriculture as well as to the increasing inflows of domestic and industrial wastewater into water bodies that are hydraulically connected with aquifers. Intensified fertilization has led to considerable groundwater quality deterioration, as evidenced by the increased nitrate concentration.

On the other hand, the coastal environment is now recognized as a crucial arena for future progress towards sustainability around the world. Approximately 70% of the population on earth lives in coastal areas and the majority of these people depend on coastal aquifers for freshwater. Many islands face problems with water. The water demands of these islands have increased during the last decades due to rapid urbanization, accelerated tourism development, agricultural activities and a continuous increase in population since the 1970s. As a result, a negative water balance has been established in coastal aquifer systems, triggering sea water intrusion, which has negative consequences in the socioeconomic development of these areas. Many coastal aquifer systems are reported to be affected by quality deterioration due to seawater intrusion and irrational management.

In this framework, the challenge is reconciling demand satisfaction and durable quality and quality sustainability of resources. This Special Issue of Water accepts the challenge, calling for any contribution on the previous subjects, including any useful innovative scientific activities. A non-exhaustive list of desired contributions includes: tools, equipment, methods, modelling, and/or experiences on hydrogeological, geophysical, geochemical mapping and aquifer characterization, including an assessment of climate change impacts on groundwater resources in terms of groundwater resource quantity and quality and/or dependent ecosystem status; tools for efficient online visualization and dissemination; risk and vulnerability assessment methods; and monitoring experiences, especially if linked to management approaches. All contributions must share the aim of contributing to success in the challenge presented by water scarcity.

Dr. Maurizio Polemio
Prof. Konstantinos Voudouris
Guest Editors

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Water is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

groundwater resource management
quantity degradation
quality degradation
pollution
coastal aquifer
climate change
modelling
monitoring
salinization
water resources

Published Papers (14 papers)

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Editorial

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8 pages, 224 KiB

Open AccessEditorial

Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability

by Maurizio Polemio and Konstantinos Voudouris

Water 2022, 14(13), 2107; https://doi.org/10.3390/w14132107 - 01 Jul 2022

Cited by 5 | Viewed by 1652

Abstract

The prospect of the global population reaching 9 billion by 2050, in addition to growing urbanisation, intensive irrigated agriculture and climate change, will add extra pressures on water resources and the environment [...] Full article

(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)

Research

Jump to: Editorial

25 pages, 30523 KiB

Open AccessFeature PaperArticle

Integrated Modeling of Agronomic and Water Resources Management Scenarios in a Degraded Coastal Watershed (Almyros Basin, Magnesia, Greece)

by Aikaterini Lyra, Athanasios Loukas, Pantelis Sidiropoulos, Konstantinos Voudouris and Nikitas Mylopoulos

Water 2022, 14(7), 1086; https://doi.org/10.3390/w14071086 - 29 Mar 2022

Cited by 5 | Viewed by 1982

Abstract

The scope of this study is to assess the effects of agronomic and water resources management scenarios on groundwater balance, seawater intrusion, and nitrate pollution and the comparison of the developed scenarios relative to the current crop production and water management regime in the coastal agricultural Almyros basin in the Thessaly region, Greece. Agronomic and water resources scenarios have been simulated and analyzed for a period of 28 years, from 1991 to 2018. The analysis has been conducted with the use of an Integrated Modeling System for agricultural coastal watersheds, which consists of coupled and interlinked simulation models of surface water hydrology (UTHBAL), reservoir operation (UTHRL), agronomic/nitrate leaching model (REPIC), and groundwater models for the simulation of groundwater flow (MODFLOW) and contaminant transport of nitrates (MT3DMS) and chlorides (SEAWAT). The pressure on water resources has been estimated with the Water Exploitation Index (WEI+) and the reservoirs’ operation with the Reliability index to cover the water demands. The indices of Crop Water Productivity, Nitrogen Use Efficiency, and Economic Water Productivity have been used to quantify the benefits and the feasibility of the alternative scenarios. The best results for the sustainability of water resources are achieved under the deficit irrigation and rain-fed scenario, while the best results for water resources and the local economy are achieved under deficit irrigation and reduced fertilization scenario. Full article

(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)

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26 pages, 8493 KiB

Open AccessArticle

Effect of Groundwater Extraction and Artificial Recharge on the Geophysical Footprints of Fresh Submarine Groundwater Discharge in the Western Belgian Coastal Area

by Marieke Paepen, Wouter Deleersnyder, Sybren De Latte, Kristine Walraevens and Thomas Hermans

Water 2022, 14(7), 1040; https://doi.org/10.3390/w14071040 - 25 Mar 2022

Cited by 9 | Viewed by 2563

Abstract

Human activities, such as managed aquifer recharge (MAR) and groundwater pumping, are influencing the natural groundwater flow in coastal areas. This might induce saltwater intrusion and impact fresh submarine groundwater discharge (FSGD). The use of resistivity methods (electrical resistivity tomography and continuous resistivity profiling) in coastal studies is very effective to investigate the salt–freshwater distribution, but it can be difficult to interpret quantitatively. In this study, the Western Belgian coast is investigated with resistivity methods, and image appraisal tools are systematically used to quantitatively interpret inversion models. Synthetic resistivity models, which reflect the existing situation at the Western Belgian coast, are first created and assessed quantitatively by means of the model resolution matrix, cumulative sensitivity matrix, and depth of investigation index. They reveal that no quantitative interpretation is possible of the FSGD, although lateral qualitative changes can be deduced from the inversion models. The field data show freshwater outflow from the lower beach to below the low water line, and they indicate that MAR has a positive impact on FSGD, while groundwater extraction reduces the outflow of freshwater to the North Sea. A comparison with existing groundwater models indicates their inability to reproduce the actual FSGD footprints. Full article

(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)

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21 pages, 5897 KiB

Open AccessArticle

Enhancing Informed Decisions for Coastal Groundwater Sustainability: A Network Analysis of Water-Related Indicator Results from 122 Cities

by Khawon Lee, Sunwoo Chang, Stef Koop, Kees van Leeuwen and Jeryang Park

Water 2022, 14(2), 262; https://doi.org/10.3390/w14020262 - 17 Jan 2022

Cited by 2 | Viewed by 1773

Abstract

In many places around the globe, groundwater has been threatened by various pressures, which calls for better management strategies for groundwater sustainability. In this study, we suggest a novel framework for identifying factors critical to coastal groundwater based on results from City Blueprint (CB) assessments. By compiling the 5856 indicator results of the City Blueprint Approach (CBA) from 122 cities and analyzing the correlation between these indicators, we constructed City Blueprint networks (CBN) by using a complex network modeling approach for three groups of cities: all 122 cities, 40 coastal, and 82 non-coastal cities. These networks were then analyzed for their node centralities to identify major factors that influence coastal groundwater management. Interestingly, our analysis revealed that groundwater has various indirect but important links with the factors that are typically unexplored in the literature. We also assessed the CB of the two largest coastal cities in South Korea. By combining the results of network analysis and CB assessment of the two cities, we could identify the indicators that are potentially at risk regarding coastal groundwater. We propose the CBN as a novel approach to unveil underestimated or hidden factors related to the target system (e.g., groundwater), which allows extensive options for sustainable groundwater management. Full article

(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)

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17 pages, 9296 KiB

Open AccessFeature PaperArticle

Hydrostratigraphic Framework and Physicochemical Status of Groundwater in the Gioia Tauro Coastal Plain (Calabria—Southern Italy)

by Giuseppe Cianflone, Giovanni Vespasiano, Rosanna De Rosa, Rocco Dominici, Carmine Apollaro, Orlando Vaselli, Luca Pizzino, Cristiano Tolomei, Francesco Capecchiacci and Maurizio Polemio

Water 2021, 13(22), 3279; https://doi.org/10.3390/w13223279 - 19 Nov 2021

Cited by 8 | Viewed by 2290

Abstract

In this study, we analysed the Gioia Tauro Plain (Tyrrhenian coast, southern Italy) in terms of hydrostratigraphy and the physicochemical status of groundwater. We investigated the hydrostratigraphic framework of the area identifying a deep aquifer (made by late Miocene succession), an aquitard (consisting of Pliocene clayey and silty deposits) and a shallow aquifer (including Late Pleistocene and Holocene marine and alluvial sediments) using subsoil data (boreholes and geophysics). Our reconstruction showed that the structural geology controls the spatial pattern of the aquitard top and the shallow aquifer thickness. Furthermore, we evaluated the hydraulic conductivity for the shallow aquifer using an empirical method, calibrated by slug tests, obtaining values ranging from 10⁻⁴ to 10⁻⁵ m/s with a maximum of 10⁻³ m/s located close to inland dune fields. The piezometric level of the shallow aquifer recorded a significant drop between the 1970s and 2021 (−35 m as the worst value). It is the effect of climate and soil use changes, the latter being the increased water demand for kiwi cultivation. Despite the overexploitation of the shallow aquifer, shallow groundwater is fresh (736 µS/cm as mean electrical conductivity) except for a narrow coastal area where the electrical conductivity is more than 1500 µS/cm, which can be due to the seawater intrusion. What was more complex was the physicochemical status of the deep aquifer characterised by high temperature (up to 25.8 °C) and electrical conductivity up to 10,520 µS/cm along the northern and southern plain boundaries marked by tectonic structures. This issue suggested the dominant role of the local fault system that is likely affecting the deep groundwater flow and its chemical evolution. Full article

(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)

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23 pages, 7674 KiB

Open AccessFeature PaperArticle

Geophysical Delineation of Freshwater–Saline Water Interfaces in Coastal Area of Southwest Bangladesh

by Md. Mizanur Rahman Sarker, Marc Van Camp, Thomas Hermans, Delwar Hossain, Mazeda Islam, Mohammad Zohir Uddin, Nasir Ahmed, Md. Abdul Quaiyum Bhuiyan, Md. Masud Karim and Kristine Walraevens

Water 2021, 13(18), 2527; https://doi.org/10.3390/w13182527 - 15 Sep 2021

Cited by 5 | Viewed by 4100

Abstract

Insufficiency of potable water is acute in southwest (SW) coastal areas of Bangladesh. The local population ignores the depth to saltwater/freshwater interface causing many unsuccessful waters wells drilling. In this context, a combined use of borehole logs, geophysical well logs, vertical electrical soundings (VES), electrical resistivity tomography (ERT) and electrical conductivity (EC) of sampled waters was performed to identify saltwater/freshwater interface depths in this coastal part. The study shows that the depth to freshwater/saltwater interface varies from place to place occurring commonly between 190 to 285 m, and locally as shallow as 146 m. The shallow freshwater/saltwater interface depth is greatly influenced by the upconing of fresh water from the deep aquifer (DA) near the major rivers and coast compared to the landward part and is mixed with more saline waters above. Vertically infiltrated saltwater is the main cause of brackish water in the upper shallow aquifer (USA), which is hydraulically connected with the lower shallow aquifer (LSA), and not directly recharged from the Bay of Bengal in the south. The study will contribute to find out the depth of the potential freshwater aquifer and assess the aquifer vulnerability in the coastal area of SW Bangladesh. Full article

(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)

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30 pages, 4992 KiB

Open AccessEditor’s ChoiceArticle

Hydrochemical Characterisation of High-Fluoride Groundwater and Development of a Conceptual Groundwater Flow Model Using a Combined Hydrogeological and Hydrochemical Approach on an Active Volcano: Mount Meru, Northern Tanzania

by George Bennett, Jill Van Reybrouck, Ceven Shemsanga, Mary Kisaka, Ines Tomašek, Karen Fontijn, Matthieu Kervyn and Kristine Walraevens

Water 2021, 13(16), 2159; https://doi.org/10.3390/w13162159 - 06 Aug 2021

Cited by 15 | Viewed by 3246

Abstract

This study characterises high-fluoride groundwater in the aquifer system on the flanks of Mount Meru, focusing on parts of the flanks that were only partially or not at all covered by previous research. Additionally, we analyse the impact of rainwater recharge on groundwater chemistry by monitoring spring discharges during water sampling. The results show that the main groundwater type in the study area is NaHCO₃ alkaline groundwater (average pH = 7.8). High F⁻ values were recorded: in 175 groundwater samples, the concentrations range from 0.15 to 301 mg/L (mean: 21.89 mg/L, median: 9.67 mg/L), with 91% of the samples containing F⁻ values above the WHO health-based guideline for drinking water (1.5 mg/L), whereas 39% of the samples have Na+ concentrations above the WHO taste-based guideline of 200 mg/L. The temporal variability in F⁻ concentrations between different seasons is due to the impact of the local groundwater recharge. We recommend that a detailed ecohydrological study should be carried out for the low-fluoride springs from the high-altitude recharge areas on the eastern and northwestern flanks of Mount Meru inside Arusha National Park. These springs are extracted for drinking purposes. An ecohydrological study is required for the management of these springs and their potential enhanced exploitation to ensure the sustainability of this water extraction practice. Another strategy for obtaining safe drinking water could be to use a large-scale filtering system to remove F⁻ from the groundwater. Full article

(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)

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17 pages, 2605 KiB

Open AccessArticle

Groundwater Modelling in Urban Development to Achieve Sustainability of Groundwater Resources: A Case Study of Semarang City, Indonesia

by Weicheng Lo, Sanidhya Nika Purnomo, Dwi Sarah, Sokhwatul Aghnia and Probo Hardini

Water 2021, 13(10), 1395; https://doi.org/10.3390/w13101395 - 17 May 2021

Cited by 10 | Viewed by 4126

Abstract

Since 1900, Semarang City has been meeting its industrial water needs by pumping groundwater through its underlying aquifers. The trend toward exploiting groundwater resources has driven the number of deep wells and their production capacity to increase, and therefore leads to the water table to drop from time to time, which has been marked as one of the primary causes of land subsidence there. The main aim of the current study was to numerically model the temporal and spatial evolution of groundwater table under excess abstraction so that a groundwater management strategy can be accordingly drawn up for ensuing the sustainability of groundwater resources in the future. A series of numerical simulations were carried out to take into account hydrogeological data, artificial and natural discharges of deep wells, and boundary effects in Semarang City. The groundwater modeling is calibrated under two flow conditions of the steady state from 1970 to 1990 and the transient state from 1990 to 2005 for six observation wells distributed in Semarang City. Four scenarios that reflect potential management strategies were developed, and then their effectiveness was systematically investigated. The results of our study indicate that the implementation of proper groundwater control management and measure is able to restore the groundwater level to rise back in Semarang City, and in turn achieve the sustainability of groundwater resources. Full article

(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)

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28 pages, 10261 KiB

Open AccessFeature PaperArticle

Impacts of Large-Scale Groundwater Exploitation Based on Long-Term Evolution of Hydraulic Heads in Dhaka City, Bangladesh

by Mazeda Islam, Marc Van Camp, Delwar Hossain, Md. Mizanur Rahman Sarker, Shahina Khatun and Kristine Walraevens

Water 2021, 13(10), 1357; https://doi.org/10.3390/w13101357 - 13 May 2021

Cited by 14 | Viewed by 5722

Abstract

Dhaka city has emerged as the fastest-growing megacity, having more than 20 million inhabitants, with a growth rate of 3.62%. Unplanned and rapid urbanization, coupled with exponential population growth, has significantly altered the groundwater dynamics in Dhaka city. This study concentrates on the evolution of long-term piezometric heads of the Upper Dupi Tila aquifer (UDA) and the Middle Dupi Tila aquifer (MDA) based on long-term hydrographs, piezometric maps and synthetic graphical overviews of piezometric trends. Due to over-exploitation, the piezometric level (PL) has declined deeper than −85 and −65 m PWD (Public Works Department reference datum) in UDA and MDA, respectively. The highest rate of decline was observed in the south-central to southeastern parts of the city both in UDA (4.0 m/year) and MDA (5.74 m/year). The results clearly show that the rates of decline in PL vary from 2.25 to 5.74 m/year in both aquifers of the city, and urban expansion has greatly affected the shape and extent of the depression cone over the past four decades. The magnitudes of the depression cones in both aquifers seem to pose a considerable threat to groundwater resources, indicating that the current exploitation is not sustainable at all. Full article

(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)

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14 pages, 4484 KiB

Open AccessFeature PaperArticle

Seawater Intrusion Proneness and Geophysical Investigations in the Metaponto Coastal Plain (Basilicata, Italy)

by Rosalba Muzzillo, Livia Emanuela Zuffianò, Enzo Rizzo, Filomena Canora, Luigi Capozzoli, Valeria Giampaolo, Giorgio De Giorgio, Francesco Sdao and Maurizio Polemio

Water 2021, 13(1), 53; https://doi.org/10.3390/w13010053 - 29 Dec 2020

Cited by 15 | Viewed by 3887

Abstract

The Metaponto coastal plain extends about 40 km along the Ionian coast, between the Sinni and Bradano Rivers (southern Italy). During the 20th century, the increases in modern irrigation systems, land reclamation works, the overexploitation of wells, and agricultural and industrial activities have deeply modified land use and groundwater availability and quality along the plain. These modifications negatively impacted the natural systems in terms of groundwater and soil salinization, magnifying the risks due to seawater intrusion. In this study, we explored the proneness to seawater intrusion, testing a multidisciplinary approach based on hydrochemical and geophysical investigations. A significant portion of the coastal plain was selected for this purpose. A set of 49 groundwater samples was analyzed to define the chemical characteristics of the water and geoelectrical measurements were recorded along three long profiles. The geoelectrical surveys showed in detail the aquifer bottom pattern where it is deeply incised by paleovalleys, defining the main hydrostratigraphic features, as it is necessary to prevent seawater intrusion worsening. The hydrochemical data highlighted areas with higher seawater intrusion proneness. The acquired measurements show the high proneness to seawater intrusion, especially where the aquifer bottom is very deep below the sea level, also far from the coast, and the relevance of the detailed knowledge of the aquifer bottom in supporting any kind of management. Full article

(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)

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24 pages, 3827 KiB

Open AccessEditor’s ChoiceArticle

How Did the Lost Shangri-La Get Lost? The Tragedy of the Groundwater Commons in Lijiang, China

by Yan Zhang

Water 2020, 12(11), 3131; https://doi.org/10.3390/w12113131 - 08 Nov 2020

Cited by 4 | Viewed by 2676

Abstract

Groundwater is critical to human survival, however, it has constantly been overexploited around the world. Despite hydrological causes and the effects of global climate change, groundwater governance has an essential role to play in causing or preventing such overexploitation. This paper presented a case of groundwater governance in Lijiang, renowned for its natural beauty and exotic cultures, located in northwest Yunnan, China. Since being designated as a UNESCO World Heritage site in the 1990s, Lijiang has experienced dramatic tourism development, which eventually escalated its groundwater crisis. This paper applied the diagnostic approach of social-ecological systems to analyse the institutionalised governance process in the case of Lijiang and substantiated the effectiveness of the Social-Ecological Systems (SES) approach in explaining groundwater management issues. Two significant findings were drawn in the case of Lijiang. First, institutional arrangements may play an essential role in resource management, but their analysis is lacking between macro modelling of planetary boundaries of the Earth and micro surveys of individual and community behaviour. The SES framework offered a useful tool to fill this gap. Second, the designation of Lijiang’s Outstanding Universal Values as a world heritage site ironically damaged its local cultural intimacy, which nurtured generations of collective action for Naxi people, escalating the tragedy of its groundwater commons. Full article

(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)

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19 pages, 5129 KiB

Open AccessArticle

Groundwater Vulnerability and Nitrate Contamination Assessment and Mapping Using DRASTIC and Geostatistical Analysis

by Moustafa El Baba, Prabin Kayastha, Marijke Huysmans and Florimond De Smedt

Water 2020, 12(7), 2022; https://doi.org/10.3390/w12072022 - 16 Jul 2020

Cited by 13 | Viewed by 3473

Abstract

The Gaza Strip is in a chronic state of water shortage and the coastal aquifer as the only freshwater source is increasingly depleted and polluted, especially by nitrate. Assessment of groundwater vulnerability to pollution is essential for adequate protection and management. In this study, the assessment of the aquifer vulnerability to contamination is derived by applying the DRASTIC procedure, firstly with original default weights and ratings and, secondly, improved by estimating rating values by multiple linear regression of observed log-transformed nitrate concentration in groundwater, with DRASTIC factors extended to land-use. The results are very different because high and low vulnerability areas shift considerably. Subsequently, a geostatistical analysis of the spatial distribution of the nitrate concentration is performed, firstly by ordinary kriging interpolation of the observed nitrate concentration and secondly by regression kriging using DRASTIC factors and land-use as indicators of the spatial variation in nitrate occurrence. These maps differ because the map obtained by regression kriging interpolation shows much more details of environmental factors such as dunes, ridges, soil types and built-up areas that affect the presence of nitrate in groundwater. The results of this study can be used by the Palestinian authorities concerned with sustainable groundwater management in the Gaza Strip. Full article

(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)

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Graphical abstract

24 pages, 9978 KiB

Open AccessArticle

Delineation of Hydraulic Flow Regime Areas Based on the Statistical Analysis of Semicentennial Shallow Groundwater Table Time Series

by Tamás Garamhegyi, István Gábor Hatvani, József Szalai and József Kovács

Water 2020, 12(3), 828; https://doi.org/10.3390/w12030828 - 15 Mar 2020

Cited by 11 | Viewed by 3166

Abstract

Shallow groundwater acts as an important source of water for the ecosystem, agriculture, drinking water supply, etc.; it is, however, among those water resources most sensitive to climate change, and especially to aridification. In the present study, the delineation of regional recharge and discharge zones of the Danube–Tisza Interfluve (Hungary, 8000 km²) is presented via the combination of multivariate time series and geomathematical methods to explore the subregions most sensitive to dewatering. The shallow groundwater level time series of 190 wells, covering a semicentennial period (1961 to 2010), were grouped into three validated clusters representing characteristically different subregions. Then, the subregions’ means and individual shallow groundwater level time series were investigated for long-term trends and compared with local meteorological variability (precipitation, evapotranspiration, etc.) to determine their regime characteristics. As a result, shallow recharge and discharge zones, a gravity-driven flow system, and the discharge zone of a deeper, overpressured flow system could be discerned with distinctive long-term changes in water levels. The semicentennial trends in shallow groundwater levels were significant (p < 0.05) in the recharge (−0.042 m y⁻¹) and in the overpressured discharge zone (0.009 m y⁻¹), and insignificant in the rest of the area (−0.005 m yr⁻¹). The present results concur with previous findings from the area but provide a statistically sound and reproducible delineation of the regime areas on a much finer scale than before. With the determination of the different climatic processes driving the semicentennial trends prevailing in the shallow groundwater, the high vulnerability of the recharge zone is underlined, while the outlined overpressured flow system seems to act independently from semicentennial precipitation trends. This study provides a more in-depth picture of the long-term changes in shallow groundwater and its drivers in of one of the most important agricultural areas in Hungary. It outlines, in a generally applicable way, the most vulnerable subareas for irrigation relaying on shallow groundwater extraction. In addition, the results can help adaptation-strategy decision makers to initiate a more effective and area-focused intervention in the case of the predicted negative trends for vulnerable recharge areas under various climate change scenarios. Full article

(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)

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Graphical abstract

25 pages, 4343 KiB

Open AccessArticle

Impacts of Emerging Agricultural Practices on Groundwater Quality in Kahe Catchment, Tanzania

by Zuberi D. Lwimbo, Hans C. Komakech and Alfred NN. Muzuka

Water 2019, 11(11), 2263; https://doi.org/10.3390/w11112263 - 28 Oct 2019

Cited by 21 | Viewed by 4949

Abstract

This paper assesses the impacts of farmers’ intensive use of agrochemicals (fertilizers and pesticides) on groundwater quality in the Kahe catchment. Samples were collected during the wet and dry seasons of the year 2018 and analyzed for the presence of agrochemicals in the water. Groundwater chemistry was dominated by magnesium-sodium-bicarbonate (Mg-Na-HCO₃⁻). The cations levels were in the trend of Mg²⁺ >Na⁺ > Ca²⁺ > K⁺, whereas anions were HCO₃⁻ > Cl⁻ > SO₄²⁻ for both seasons. The NO₃⁻ had an average value of about 18.40 ± 4.04 and 7.6 ± 1.7 mg/L in the wet and dry season, respectively. Elevated levels of nitrate, sulfate, phosphate, and ammonium were found in water samples collected near the large-scale sugarcane plantation in the catchment. For both seasons, Pb, Cd, Fe, Mn, Zn and Cu concentrations averaged approximately 0.08 ± 0.03, 0.11 ± 0.03, 0.16 ± 0.02, 0.11 ± 0.01, 0.46 ± 0.05, and 0.55 ± 0.02 mg/L, respectively. On the other hand, the concentrations were higher in shallow wells than in the deep boreholes. Pesticides’ residues were below the detection limit in all sampled groundwater. The findings from this study provide important information for intervention in groundwater quality management in Kahe Catchment, Tanzania. Full article

(This article belongs to the Special Issue Groundwater Resources Management: Reconciling Demand, High Quality Resources and Sustainability)

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