scholarly journals Statistical approaches and hydrochemical modelling of groundwater system in a small tropical island

2011 ◽  
Vol 14 (1) ◽  
pp. 206-220 ◽  
Author(s):  
A. Z. Aris ◽  
S. M. Praveena ◽  
M. H. Abdullah ◽  
M. Radojevic
Keyword(s):  
Seawater Intrusion ◽  
Exchange Process ◽  
Factor Scores ◽  
Groundwater System ◽  
Groundwater Exploitation ◽  
Monitoring Wells ◽  
Hydrochemical Modelling ◽  
Aquifer Salinization ◽  
Hydrochemical Model ◽  
Statistical Approaches

The aquifer of Manukan Island of Borneo, Malaysia had been found to be affected by seawater intrusion associated with excessive groundwater exploitation. This research attempted to characterize the chemistry of an impacted zone in the island using factor analysis (FA), cluster analysis (CA) and a hydrochemical model package (PHREEQC). The factor scores were used to plot the spatial map and to group the relationships among the monitoring wells using CA. The results of FA analysis revealed that the three main processes associated with the seawater intrusion event are aquifer salinization, cation exchange process and redox sequences. Output from the PHREEQC simulation was used to support the findings from the multivariate analysis.

scholarly journals Analysis of Water Cycle in Weizhou Island of Beihai City, Guangxi Province, Part II: Study On Groundwater Exploitation Plan

2018 ◽  
Vol 246 ◽  
pp. 02047
Author(s):  
Shunfu Zhang ◽  
Changjun Liu ◽  
Chuanke Li ◽  
Sili Long ◽  
Jian Zhou ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
Ground Water ◽  
Seawater Intrusion ◽  
Groundwater Level ◽  
Water Cycle ◽  
Variable Density ◽  
Analysis Model ◽  
Guangxi Province ◽  
Groundwater Exploitation ◽  
Groundwater Levels

To relieve the drop of groundwater and seawater intrusion in Weizhou Island caused by overexploitation, the analysis model of precipitation-runoff and variable-density groundwater flow in Weizhou Island was established and the model’s parameter identification results were used to investigate groundwater level and seawater/freshwater interface changes under different groundwater exploitation plans. Thereafter, a rational groundwater exploitation plan could be made to prevent the lowering of groundwater levels caused by ground water overexploitation and ecological deterioration caused by seawater intrusion. This could help accelerating the recovery of ground water and maintaining ecological system.

scholarly journals Intrusion of Saline Water into a Coastal Aquifer Containing Palaeogroundwater in the Viimsi Peninsula in Estonia

Geosciences ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 47
Author(s):  
Valle Raidla ◽  
Joonas Pärn ◽  
Werner Aeschbach ◽  
György Czuppon ◽  
Jüri Ivask ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Seawater Intrusion ◽  
Saline Water ◽  
Sole Source ◽  
Crystalline Basement ◽  
Monitoring Networks ◽  
Radium Isotopes ◽  
Groundwater Exploitation ◽  
Aquifer System ◽  
North East

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.

scholarly journals Seawater Intrusion into Coastal Aquifers

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2719
Author(s):  
Eyal Shalev
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Submarine Groundwater Discharge ◽  
Groundwater Discharge ◽  
Climate Variations ◽  
Special Issue ◽  
Groundwater Exploitation ◽  
Major Constraint ◽  
Highly Sensitive ◽  
Submarine Groundwater

This editorial presents a representative collection of 11 papers presented in the Special Issue on Seawater Intrusion into coastal aquifers. Coastal aquifers are one of the most important water resources in the world. In addition, the natural discharge of freshwater to the sea as submarine groundwater discharge (SGD) has an important role in the ecology of marine environments. The dynamics of seawater and freshwater within coastal aquifers are highly sensitive to disturbances, and their inappropriate management may lead to the deterioration of water quality. In many coastal aquifers, seawater intrusion has become the major constraint imposed on groundwater utilization. Groundwater exploitation and climate variations create dynamic conditions, which can significantly increase seawater intrusion into aquifers and may result in the salinization of wells.

Evaluation the freshwater-saltwater interface using geophysical and geochemical investigations within the single borehole

2020 ◽  
Author(s):  
Seho Hwang ◽  
Jehyun Shin ◽  
Yongje Kim ◽  
Sooyoung Cho ◽  
Sang-Ho Moon ◽  
...  
Keyword(s):  
Water Quality ◽  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Seawater Intrusion ◽  
High Electrical Conductivity ◽  
Fracture Zones ◽  
Monitoring Wells ◽  
Groundwater Samples ◽  
Survey Line ◽  
Tidal Changes

<p>The Korean peninsula has three sides facing the sea, and many monitoring wells for seawater intrusion observation installed along these coasts. The electrical conductivity (EC) profiles of these monitoring wells are found to vary greatly depending on the hydrogeological characteristics of the coast. The research area is located in Seocheon, Chungnam, where two wells are about 1.5 km away, one borehole is freshwater and the other boreholes have high electrical conductivity. In the well where the high electrical conductivity is measured, the electrical conductivity increases rapidly at a depth of about 90m. The well is located about 50 meters from the coast, and the change in water level reflects tidal changes well. We conducted a variety of field surveys and laboratory tests to clarify whether seawater intrusion occurred in the freshwater-saltwater boundary at the depth of about 90 m and whether the freshwater-saltwater boundary was affected by tides. Applied methods are electrical resistivity survey, geophysical well logging and geochemistry. The geophysical survey line was located along the coast centered on the well and measured every six hours. As a result of the survey, it was difficult to identify the change of electrical resistivity due to tidal changes in the lower alluvial zone, that is, the rock formation. These result indicates that the permeable fracture zones are rarely distributed in the rock below the survey line, so the change of the formation resistivity of according to the tidal change is very small. Geophysical well logs such as optical televiewer, spectral gamma log, and water quality logs (i.e., temperature, EC, pH, DO, and ORP) were measured, and groundwater samples were collected according to depth and analyzed for T, EC, pH, DO, ORP, and 222Rn. We found it difficult to identify permeability fracture zones in the temperature gradient and optical televiewer logs. The electrical conductivity is generally around 4,000 uS/cm and increase rapidly from about 90m to 48,000 uS/cm. The water quality logs and the analysis of groundwater samples showed pH range of about 7 to 7.5, DO of 7 to 14 mg/L, and OPR of -80 to 180 mV. pH does not change with depth, DO decreases slightly, and ORP decreases rapidly around the fresh-saltwater interface. The analysis of 222Rn shows that, to the median depth of the borehole, it is similar to the intensity of natural gamma rays and decreases rapidly across the lower freshwater-saltwater interface. Finally, we measured the electrical conductivity logs repeatedly at the interval of 30 minutes in the lower borehole where the freshwater-saltwater boundary was formed, and identified that the profiles of electrical conductivity change with tides.</p>

scholarly journals Fe and As geochemical self-removal dynamics in mineral waters: evidence from the Ferrarelle groundwater system (Riardo Plain, Southern Italy)

2021 ◽  
Author(s):  
Emilio Cuoco ◽  
Stefano Viaroli ◽  
Vittorio Paolucci ◽  
Roberto Mazza ◽  
Dario Tedesco
Keyword(s):  
Southern Italy ◽  
Dilution Effect ◽  
Mineral Waters ◽  
Angular Coefficient ◽  
Groundwater System ◽  
Specific Chemical ◽  
Monitoring Wells ◽  
Theoretical Pattern ◽  
Co Precipitation ◽  
Good Agreement

AbstractA theoretical pattern for Fe and As co-precipitation was tested directly in a groundwater natural system. Several monitoring wells were sampled to identify the different endmembers that govern the hydrodynamics of the Ferrarelle Groundwater System in the Riardo Plain (Southern Italy). In agreement with recent investigations, we found a mix of a deep and a shallow component in different proportions, resulting in a specific chemical composition of groundwater in each well depending on the percentages of each component. The shallow component was characterized by EC ~ 430 µS/cm, Eh ~ 300 mV, Fe ~ 0.06 µmol/L and As ~ 0.01–0.12 µmol/L, while the deep component was characterized by EC ~ 3400 µS/cm, Eh ~ 170 mV, Fe ~ 140 µmol/L and As ~ 0.59 µmol/L. A general attenuation of As and Fe concentration that was not due to a simple dilution effect was observed in the mixing process. The oxidation of Fe(II) to Fe(III) produces solid precipitates which adsorb As from solution and then co-precipitate. The reactions pattern of Fe(II) oxidation and As adsorption gave a linear function between [As] and [Fe], where the angular coefficient depends on the [O2]/[H+] ratio. Chemical data obtained from our samples showed a very good agreement with this theoretical relationship. The investigated geochemical dynamics represented a natural process of attenuation of Fe and As, two undesirable elements that usually affect groundwater quality in volcanic aquifers in central-southern Italy, which are exploited to supply drinking water. Graphic abstract

scholarly journals Modelling tools for quantitative evaluations on the Versilia coastal aquifer system (Tuscany, Italy) in terms of groundwater components and possible effects of climate extreme events

2020 ◽  
Vol 9 (3) ◽  
Author(s):  
Matia Menichini ◽  
Marco Doveri
Keyword(s):  
Seawater Intrusion ◽  
Extreme Events ◽  
Coastal Aquifer ◽  
Climate Extreme ◽  
Aquifer Recharge ◽  
Hydrogeological Model ◽  
Groundwater Exploitation ◽  
Aquifer System ◽  
Open Platform ◽  
Adequate Knowledge

The Versilia coastal plain hosts an important and strategic aquifer for water supply. Like all coastal aquifers, it is particularly vulnerable to the saltwater intrusion, which can be amplified not only by fresh water over-exploitation, but also by the effects of climate change, including the increase of extreme events. For an optimal management of this precious resource and for its protection both in quantitative and qualitative terms, an adequate knowledge of the aquifer system is necessary through the development of conceptual and mathematical hydrogeological models. The conceptual hydrogeological model was defined on the base of an integrated multidisciplinary approach with the elaboration of stratigraphic, hydrogeological and geochemical-isotopic data. Subsequently, groundwater flow mathematical models were created using the ModFlow code and Groundwater Vistas like graphical interface, subsequently transferred to the Freewat open platform. The models enabled acquiring further knowledge about this aquifer system and to identify and, where possible to quantify, the main processes and groundwater components involved, including the seawater ingression. An important groundwater component, both in terms of water quantity and quality,resulted widespread in the fan of the Versilia River and mainly fed by the river itself in the foothill zone. Although this component seems to be able to guarantee relative protection against marine ingression, in the summer season some piezometric depressions tied to groundwater exploitation tend to expand and move towards the coast, thus favouring the seawater intrusion process. These issues can be amplified by the extreme rainy events that frequently occur in the Apuan Alps region. The huge quantity of water that quickly flows by the river up to the sea during extreme events represents a lack of feeding respect to the aquifer, and consequently the mitigation role of the fan component towards seawater intrusion can be significantly weakened. Thanks to the water budget achieved by numerical model and considering real extreme events recently occurred in the Apuan-Versilian region it was possible to make considerations about possible effects these climate regimes on the aquifer system. As outcomes, we concluded that extreme events as those occurred in the area in the past, and awaited more frequently in the future, represent a concrete threat for the coastal aquifer system that over next decades could suffer more and more seawater intrusion. Given the reliance of local human activities on groundwater, far-sighted actions of water management (e.g. managed aquifer recharge) are recommended for mitigating such as climate effects.

Groundwater and salinization risk: tapping works and management experience in the Mediterranean Area

2021 ◽  
Author(s):  
Giorgio De Giorgio ◽  
Livia Emanuela Zuffianò ◽  
Maurizio Polemio
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Groundwater Resources ◽  
Regional Scale ◽  
Mediterranean Area ◽  
Management Approach ◽  
Fresh Groundwater ◽  
Groundwater Exploitation ◽  
Saline Groundwater ◽  
The Mediterranean

<p>The progressive population growth in coastal areas constitutes a huge worldwide problem, particularly relevant for coastal aquifers of the Mediterranean basin.</p><p>The increasing use of groundwater and the effect of seawater intrusion makes the study of coastal aquifers extremely relevant.</p><p>There are various measures, practices, and actions throughout the world for managing groundwater when this natural resource is subject to salinization risk.</p><p>This research focused on the seawater intrusion, classifies the different practical solutions protecting the groundwater through salinization mitigation and/or groundwater salinity improvements along the Mediterranean Area.</p><p>The literature review was based on 300 papers, which are mainly international journal articles (76%). The rest includes conference papers (11.8%), reports and theses (7%), and books or chapters of a book (25%).</p><p>Three main schematic groundwater management approaches can be distinguished for the use of groundwater resources at risk of salinization.</p><p>The <strong>engineering approaches</strong> pursue locally the discharge increase avoiding or controlling the salinity increase.</p><p>The most recent experiences of tapping submarine springs were realized using underground concrete dams, tools shaped like a parachute or tulip, or a fiberglass telescopic tube-bell, especially in the case of karstic aquifers.</p><p>The current widespread form of the engineering approach is to address the issue of groundwater exploitation by wells.</p><p>More complex solutions use subhorizontal designs. Subhorizontal tapping schemes were realized using tunneling and/or boring in combination with wide-diameter wells or shafts.</p><p>These works include horizontal drains or radial tunnels bored inside the saturated aquifer, shafts excavated down to the sea level with radial galleries or drains realized together with weirs to improve the regulation of the discharge rate and of salinization. Application of these solutions in areas where a thin fresh groundwater lens floats on the saline groundwater, as in the case of narrow and highly permeable islands, can yield high discharges, thus causing a very low drawdown over very wide areas. These solutions were successfully applied in Malta Islands.</p><p>The <strong>discharge management approach</strong> encompasses at least an entire coastal aquifer and defines rules concerning groundwater utilization and well discharge.</p><p>A multi-methodological approach based on monitoring networks, spatiotemporal analysis of groundwater quality changes, and multiparameter well logging is described in Apulian karstic coastal aquifers (Italy). The core is the definition of the salinity threshold value between pure fresh groundwater and saline groundwater mixture. The basic tools were defined to be simple and cost-effective to be applicable to the widest range of situations.</p><p>The <strong>water and land management approach</strong> should be applied on a regional scale. The main choice for this approach is pursuing water-saving measures and water demand adaptation. A multiple-users and multiple-resources-water supply system model was implemented to evaluate the effectiveness of the increasing maximum capacity of the surface reservoir and managed aquifer recharge in Apulia, a semi-arid region of Southern Italy.</p>

Assessment of Aquifer Salinization Beneath an Offshore Industrial Park Based on Solute Transport Calculation

2013 ◽  
Vol 779-780 ◽  
pp. 1285-1288
Author(s):  
Shu Yun Liang ◽  
Ting Nien Wu ◽  
Yu Sheng Wu ◽  
Yen Chin Chou ◽  
Cheng Haw Lee
Keyword(s):  
Solute Transport ◽  
Saline Water ◽  
Chloride Concentration ◽  
Temporal Variations ◽  
Total Dissolved Solids ◽  
Industrial Park ◽  
Monitoring Wells ◽  
Island Type ◽  
Aquifer Salinization ◽  
Transport Calculation

The purpose of this study is to assess aquifer salinization in the coastal area of an Offshore Industrial Park in Taiwan. Study area belongs to the new Delta Holocene alluvium, which is composed of clay, silt, sand, gravel and their mixture. Groundwater quality measurements including electrical conductivity, total dissolved solids, chloride and sulfate were used as indicator to evaluate aquifer salinization. Regional groundwater flows from the middle of study area to the embracing beach, which is the typical island-type-like distribution of groundwater lens. Temporal variations of chloride concentrations in monitoring wells were simulated based on the calculation of solute transport. The simulation result matched with the observation that rainfall leaching could cause dilution of chloride concentration and lessen aquifer salinization. Solute exchange at the interface of fresh water and saline water strongly affected desalinization rate in groundwater, and thus desalinization rate was dependent on its distance from the seashore. According to the calculation of solute transport, it might take about 14 years for complete desalinization through continual rainfall leaching.

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