Upconing of saline water from the crystalline basement into the Cambrian–Vendian aquifer system on the Kopli Peninsula, northern Estonia

The Viimsi peninsula is located north-east of Tallinn, capital of Estonia. The Cambrian-Vendian (Cm-V) aquifer system is a sole source of drinking water in the area. Historically, the groundwater exploitation has led to freshening of groundwater in the peninsula, but in recent years an increase in chloride concentrations and enrichment in δ18O values has been detected, but in recent years hydrochemical parameters indicate an increasing influence of a saline water source. The exact origin of this saline water has remained unclear. The aim of the current study is to elucidate whether the increase in Cl− concentrations is related to seawater intrusion or to the infiltration of saline water from the underlying crystalline basement. To identify the source of salinity, chemical composition of the groundwater and the isotope tracers (e.g., δ18O and radium isotopes) were studied in the Viimsi peninsula in the period from 1987 to 2018. Our results show that chemical composition of Cm-V groundwater in the peninsula is clearly controlled by three-component mixing between glacial palaeogroundwater, saline water from the underling crystalline basement and modern meteoric water. The concentrations of Ra are also significantly affected by the mixing, but the spatial variation of radium isotopes (226Ra and 228Ra) suggests the widespread occurrence of the U in the surrounding sedimentary sequence. Our hypothesis is that, in addition to U originating from the crystalline basement, some U could be associated with secondary U deposits in sedimentary rocks. The formation of these secondary U deposits could be related to glacial meltwater intrusion in the Pleistocene. Although the results suggest that the infiltration of saline groundwater from the underlying crystalline basement as the main source of salinity in the study area, the risk of seawater intrusion in the future cannot be ruled out. It needs to be highlighted that the present groundwater monitoring networks may not be precise enough to detect the potential seawater intrusion and subsequent changes in water quality of the Cm-V aquifer system in the Viimsi peninsula.

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Quantitative estimations of aquifer properties from resistivity in the Bolivian highlands

H2Open Journal ◽

10.2166/h2oj.2019.007 ◽

2019 ◽

Vol 2 (1) ◽

pp. 113-124

Author(s):

Etzar Gómez ◽

Viktor Broman ◽

Torleif Dahlin ◽

Gerhard Barmen ◽

Jan-Erik Rosberg

Keyword(s):

Hydraulic Conductivity ◽

Saline Water ◽

Cost Effective ◽

Unconsolidated Sediments ◽

Aquifer System ◽

Transient Electromagnetic ◽

Rock Formations ◽

Hydrogeological Characteristics ◽

Electrical Soundings ◽

Available Information

Abstract Resistivity data constitute the largest part of the available information to assess the hydrogeological characteristics of the aquifer system near Oruro, in the central part of the Bolivian Altiplano. Two aquifers are part of this system; top unconsolidated sediments storing fresh water in their granular voids, overlying fractured hard rock formations where saline water was detected in connection to some faults. This study proposes an indirect and cost-effective way to estimate aquifer hydraulic properties for the groundwater management in the region. Hydraulic conductivity and transmissivity in the top aquifer were estimated using an empirical linear relationship between hydraulic conductivity and resistivity. This latter parameter, as well as the aquifer thickness, were obtained from the inverted models corresponding to the geoelectrical tests performed in the study area (electrical resistivity tomography, transient electromagnetic soundings and vertical electrical soundings). The highest estimated transmissivity values are ∼4.0 × 10−2 m2/s located in the centre of the study area, the lowest values are ∼3.4 × 10−3 m2/s, located around thermal intrusions to the south and where the top of the bedrock is shallow (∼20 m depth) to the west. The methodology presented in this study makes wider use of resistivity measurements to identify promising groundwater production sites.

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Configuration of freshwater/saline-water interface and geologic controls on distribution of freshwater in a regional aquifer system, central lower peninsula of Michigan

10.3133/wri944242 ◽

1996 ◽

Keyword(s):

Saline Water ◽

Water Interface ◽

Aquifer System ◽

Lower Peninsula ◽

Regional Aquifer ◽

Geologic Controls

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AVALIAÇÃO PRELIMINAR DAS CONDIÇÕES HIDROGEOLÓGICAS NA ÁREA DO MUNICÍPIO DE OURO PRETO, MG.

Revista Geonomos ◽

10.18285/geonomos.v18i1.63 ◽

2013 ◽

Author(s):

Quênia de Cássia Goulart Ferreira ◽

Luis de Almeida Prado Bacellar

Keyword(s):

Crystalline Basement ◽

Primary Data ◽

Inorganic Elements ◽

Aquifer System ◽

Aquifer Systems ◽

Chemical Conditions ◽

Physical And Chemical ◽

The City ◽

Iron Formations ◽

Made In

O conhecimento da dinâmica natural e da qualidade das águas subterrâneas no município de Ouro Preto éainda deficiente. Em vista disto, foi elaborado um banco de dados hidrogeológicos com o intuito de avaliarde forma preliminar o potencial hídrico subterrâneo desta área. A análise e tratamento dos dados secundáriose primários obtidos permitiu a identificação de oito sistemas aqüíferos. O sistema do Grupo Itabira, ondese encontram as formações ferríferas da Formação Cauê, é o de maior potencial. Os sistemas em rochasdo embasamento cristalino destacam-se pelo maior número de poços tubulares cadastrados. Análises deparâmetros físico-químicos e de elementos inorgânicos na água subterrânea revelaram que a maioria apresentaconcentrações inferiores aos máximos permitidos pela legislação para água potável. Contudo, como o sistemade proteção sanitária dos poços se mostrou muitas vezes inadequado, é possível que haja alguma contaminaçãopor elementos ou compostos não analisados e que deverão ser futuramente investigados.Palavras-chaves: hidrogeologia, sistemas aqüíferos, hidroquímica, Ouro Preto. ABSTRACT: The knowledge of physical and chemical conditions of groundwater in the city of Ouro Preto is still deficient.Therefore, in this paper a hydrogeological database was made, in order to estimate the groundwater potentialof the area. The analysis and processing of secondary and primary data allowed the identification of eightaquifer systems. The aquifer system of the Itabira Group, with iron formations, was considered the best,while the crystalline basement system has the highest number of registered wells. Analysis of physicalchemicalparameters and inorganic elements in groundwater has revealed that most concentrations are belowthe maximum allowed by law for drinking water. owever, the sanitary protection of the wells is frequentlyinadequate and there are ossibly other contaminants, which should be further investigated.Keywords: hydrogeology, aquifer systems, hydrochemistry, Ouro Preto.

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Managing saltwater intrusion in coastal arid regions and its societal implications for agriculture

Proceedings of the International Association of Hydrological Sciences ◽

10.5194/piahs-373-31-2016 ◽

2016 ◽

Vol 373 ◽

pp. 31-35 ◽

Cited By ~ 7

Author(s):

Jens Grundmann ◽

Ayisha Al-Khatri ◽

Niels Schütze

Keyword(s):

Saltwater Intrusion ◽

Saline Water ◽

Management Strategies ◽

Point Of View ◽

Decision Makers ◽

Societal Implications ◽

Irrigated Agriculture ◽

Natural Rate ◽

Aquifer System ◽

Management Interventions

Abstract. Coastal aquifers in arid and semiarid regions are particularly at risk due to intrusion of salty marine water. Since groundwater is predominantly used in irrigated agriculture, its excessive pumping – above the natural rate of replenishment – strengthen the intrusion process. Using this increasingly saline water for irrigation, leads to a destruction of valuable agricultural resources and the economic basis of farmers and their communities. The limitation of resources (water and soil) in these regions requires a societal adaptation and change in behaviour as well as the development of appropriate management strategies for a transition towards stable and sustainable future hydrosystem states. Besides a description of the system dynamics and the spatial consequences of adaptation on the resources availability, the contribution combines results of an empirical survey with stakeholders and physically based modelling of the groundwater-agriculture hydrosystem interactions. This includes an analysis of stakeholders' (farmers and decision makers) behaviour and opinions regarding several management interventions aiming on water demand and water resources management as well as the thinking of decision makers how farmers will behave. In this context, the technical counter measures to manage the saltwater intrusion by simulating different groundwater pumping strategies and scenarios are evaluated from the economic and social point of view and if the spatial variability of the aquifer's hydrogeology is taken into consideration. The study is exemplarily investigated for the south Batinah region in the Sultanate of Oman, which is affected by saltwater intrusion into a coastal aquifer system due to excessive groundwater withdrawal for irrigated agriculture.

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High Resolution Monitoring of Seawater Intrusion in a Multi-Aquifer System-Implementation of a New Downhole Geophysical Tool

Water ◽

10.3390/w11091877 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1877 ◽

Cited By ~ 3

Author(s):

Tal ◽

Weinstein ◽

Baïsset ◽

Golan ◽

Yechieli

Keyword(s):

Electrical Conductivity ◽

Electric Conductivity ◽

Seawater Intrusion ◽

Saline Water ◽

Near Field ◽

Aquifer System ◽

Monitoring Wells ◽

New Device ◽

Subsurface Monitoring ◽

The Impact

Monitoring of seawater intrusion is extremely important for the management of coastal aquifers, and therefore requires reliable and high-frequency monitoring tools. This paper describes the use of a new near field and downhole geophysical tool that monitors seawater intrusion in boreholes with high vertical resolution. This sensor is further used to study the impact of pumping on water electrical conductivity profiles (ECP) at the fresh-saline water interface. The new device was installed in a confined calcareous sandstone aquifer along the northern Israeli coast. The site includes two monitoring wells and one pumping well located at distances of 50, 75 and 125 m from shoreline, respectively. The new geophysical tool, called the subsurface monitoring device (SMD), was examined and compared to water an electric conductivity profiler (ECP) and a conductivity temperature depth (CTD) driver’s data. All methods show similar salinity trends, and changes in pumping regime were clearly identified with both the SMD and CTD. The advantage of using the SMD tool is the high temporal and spatial resolution measurement, which is transferred via internet and can be analyzed and interpreted in real time. Another advantage of the SMD is that it measures the electrical resistivity of the aquifer mostly outside the well, while both water ECP and the CTD measure in-well electrical conductivity; therefore, are subjected to the artefact of vertical flow in the well. Accordingly, while the CTD shows an immediate and sharp response when pumping is stopped, the SMD provides a gradual electric conductivity (EC) change, demonstrating that stability is reached just after a few days, which illustrates, more precisely, the hydrological response of the aquifer.

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Surface Resistivity Sounding and Borehole Data Analysis for the Evaluation of Aquifer Characteristics of Southern Districts Barguna and Patuakhali, Bangladesh

The Dhaka University Journal of Earth and Environmental Sciences ◽

10.3329/dujees.v8i1.50755 ◽

2020 ◽

Vol 8 (1) ◽

pp. 11-18

Author(s):

Md Tariqul Islam ◽

ASM Woobaidullah

Keyword(s):

Fresh Water ◽

Saline Water ◽

Resistivity Measurement ◽

Surface Resistivity ◽

Borehole Data ◽

Deep Aquifer ◽

Aquifer System ◽

Low Resistivity ◽

Resistivity Method ◽

Set Up

The study delineates the aquifer system of the study area and determines the extension of potential fresh water aquifer and suitable locations for groundwater development through geophysical electrical resistivity method. Vertical electrical sounding with Schlumberger electrode configuration, a method for surface resistivity measurement, has been used for data collection. Resistivity data along with borelog data analyses are used for this investigation. Lithological cross section analyses show that sand and clay dominated lithology with frequent facies changes occur throughout the area and also show an aquifer system similar to the three-tier aquifer system proposed by Aggarwal for coastal area of Bangladesh. This study reveals the presence of three aquifers. 1staquifer occurs at a very shallow depth at some places <5 m and thickness of the aquifer varies 10-70 m all over the region, and shows very low resistivity value indicating saline pore water. Average depth to the 2nd aquifer ranges from 60-70 m and also contaminated by saline water. In few places of 2nd aquifer resistivity values more than 20 Ωm suggest some fresh water pockets. Depth to the 3rd aquifer that spreads all over the study area is more than 220 m at maximum part of the area. Only potential fresh water aquifer is the 3rd or deep aquifer, but low resistivity values of this aquifer at Patharghata and small portion of Kalapara and Rangabali Upazilas hint that there may have saline water intrusion. More precise information for this complex geological set up require greater number of sounding points. The Dhaka University Journal of Earth and Environmental Sciences, Vol. 8(1), 2019, P 11-18

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The Ohlsbach Plume – Discharge of deep saline water from the crystalline basement of the Black Forest, Germany

Hydrogeology Journal ◽

10.1007/s100400050201 ◽

1999 ◽

Vol 7 (3) ◽

pp. 273-283 ◽

Cited By ~ 25

Author(s):

Ingrid Stober ◽

Almuth Richter ◽

Eva Brost ◽

Kurt Bucher

Keyword(s):

Saline Water ◽

Crystalline Basement ◽

Black Forest

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Groundwater microbial diversity and antibiotic resistance linked to human population density in Yucatan Peninsula, Mexico

Canadian Journal of Microbiology ◽

10.1139/cjm-2019-0173 ◽

2020 ◽

Vol 66 (1) ◽

pp. 46-58 ◽

Cited By ~ 1

Author(s):

Anni Moore ◽

Melissa Lenczewski ◽

Rosa Maria Leal-Bautista ◽

Melvin Duvall

Keyword(s):

Antibiotic Resistance ◽

Microbial Diversity ◽

Saline Water ◽

Yucatan Peninsula ◽

Karst Aquifer ◽

Microbial Community Composition ◽

Aquifer System ◽

Cave System ◽

Antibiotic Resistance Profile ◽

Yucatán Peninsula

Microbial community composition in selected karst groundwater sites in the Yucatan Peninsula, Mexico, was assessed to determine the environmental variables influencing groundwater microbial diversity. The karst aquifer system is a groundwater-dependent ecosystem and is the world’s second largest underwater karst cave system. The area’s geology allows precipitation to infiltrate into the groundwater system and prevents accumulation of surface water; as such, groundwater is the only source of fresh water on the peninsula. The sampling locations consisted of three karst sinkholes that extend through the freshwater zone into the saline water, and an abandoned drinking water well of an ocean-side resort, during the dry and rainy seasons. The analysis showed that highly diverse microbial communities are present in the Yucatan groundwater, sustained by permanently warm temperatures and high nutrient input from human activity. Proximity to densely populated areas, such as tourist resorts, is the most important factor influencing both the diversity and presence of fecal bacteria and the antibiotic resistance profile.

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A Multidisciplinary Approach for Clarifying the Recharge Processes and Origin of Saline Water in the Semi-Arid Punata Alluvial fan in Bolivia

Water ◽

10.3390/w10070946 ◽

2018 ◽

Vol 10 (7) ◽

pp. 946 ◽

Cited By ~ 3

Author(s):

Andres Gonzales Amaya ◽

Gerhard Barmen ◽

Galo Muñoz

Keyword(s):

Stable Isotopes ◽

Ion Exchange ◽

Saline Water ◽

Bottom Layer ◽

Alluvial Fan ◽

Aquifer System ◽

Fine Grained ◽

The North ◽

Geophysical Surveys ◽

Interpretation Process

The analysis of stable isotopes assisted in identifying that groundwater in the Punata alluvial fan is mainly recharged by heavy flash floods, and the recharge from rainfall is of less importance. In addition, the hydrochemical analysis identified the Pucara River as the main source of recharge. Other streams in the north and northwest of the fan do not seem to contribute to the recharge. The hydrochemistry also shows that there is an increase of the Na+ and Cl− concentrations in the middle and distal part of the fan. The salinization of groundwater is most likely a result of the mixing of fresh water with residual saline pore water in the lacustrine deposits and/or ion exchange within these layers. Geophysical surveys assisted in describing the aquifer system layering, and indicated a fine-grained bottom layer where ion exchange might occur. This study demonstrates that the integration of several methods (e.g., hydrochemistry, hydrogeophysics, and stable isotopes) is valuable for clarifying ambiguities during the interpretation process and for characterizing hydrogeological processes in alluvial fans in general.

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