Assessment of groundwater vulnerability to anthropogenic pollution and seawater intrusion in a small tropical island using index-based methods

Kura, Nura Umar; Ramli, Mohammad Firuz; Ibrahim, Shaharin; Sulaiman, Wan Nor Azmin; Aris, Ahmad Zaharin; Tanko, Adamu Idris; Zaudi, Muhammad Amar

doi:10.1007/s11356-014-3444-0

Cited by 77 publications

(23 citation statements)

References 43 publications

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“…Impact of existing seawater intrusion in the area (I): This parameter considers the existing occurrence of SWI. The molar ratio of chloride ions to bicarbonate ions (Cl − /[HCO + CO 3 ]) is used as a measure of the degree of seawater intrusion into a coastal aquifer in standard GALDIT studies [4,20,21,26]. In this study, instead of the molar ratio or Cl − concentration, electrical conductivity (EC) was adopted as a GALDIT index parameter because EC data is currently being collected by a groundwater monitoring network in Jeju.…”

Section: Galdit Indexing Of Parameters For Jeju Islandmentioning

confidence: 99%

“…The pattern of SWI is highly correlated with the characteristics of associated regions. In particular, SWI severely affects the water use and management for islands and some coastal regions where groundwater is the only source of freshwater [2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

“…The parameters used are the groundwater occurrence (G), aquifer hydraulic conductivity (A), height of the groundwater level above sea level (L), distance inland perpendicular from the shoreline (D), impact of existing seawater intrusion in the area (I), and thickness of the aquifer considered (T). Many studies have employed the GALDIT method to assess the overall vulnerability of coastal aquifers to SWI in coastal regions and islands of different countries in Europe, Asia, and Africa over very small (2 km 2 ) and large (2835 km 2 ) areas [4,[22][23][24][25][26][27].Lobo-Ferreira and Chachadi [21,22] used GALDIT to conduct vulnerability tests on an unconfined aquifer covering an area of approximately 10 km 2 at Monte Gordo, Portugal. They mapped the spatial distributions of the six GALDIT parameters and prepared SWI scenarios describing sea level rises of 0.25 and 0.5 m and applied them to the parameter G to calculate the vulnerability depending on individual scenarios.…”

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confidence: 99%

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Application of GALDIT in Assessing the Seawater Intrusion Vulnerability of Jeju Island, South Korea

Chang

Chung

Kim

et al. 2019

Water

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Seawater intrusion (SWI) is a major environmental threat to groundwater resources in coastal regions. GALDIT is an index-based SWI vulnerability model that is increasingly being used in many parts of the world to identify regions that are vulnerable to various types of SWI based on six major parameters. In this study, we conducted a vulnerability assessment of Jeju Island to SWI based on several years of collected groundwater level data and hydrogeological values where the objectives of the study were to visualize the distribution of recent SWI, to increase the reliability of the GALDIT assessment method by improving current GALDIT techniques, and to respond effectively to diagnoses of SWI on Jeju. To improve the GALDIT assessment method to fit the Jeju model, the possibility of electrical conductivity was explored instead of standard GALDIT parameters that represented the existing impact of SWI. Improvements to the GALDIT vulnerability assessment method made it clear that groundwater became increasingly vulnerable to SWI in the existing high-vulnerability group. The results of this research may be used to develop a quantitative index for rational decision-making on policies and suggest the need for further improvements in groundwater management, with a stronger focus on easing groundwater use.2 of 17 index method. Numerical simulations reproduce the dynamics of groundwater flow and salt transport in the coastal aquifer and can incorporate site characteristics [2,[7][8][9][10][11][12]. However, despite their accuracy and usefulness, numerical simulations require a considerable amount of hydrogeologic data as input and a difficult calibration process, therefore substantial computing power is needed for data processing and modeling.An alternative vulnerability assessment method uses a steady-state analytical solution based on the sharp interface model with the Ghyben-Herzberg principle, where the mixing of freshwater and saltwater is neglected and instead a sharp interface is assumed [13]. The sharp interface model is often employed to assess the vulnerability of aquifers to the effects of SWI because of the relatively easy and rapid computations. For example, Werner et al. [14] proposed a SWI vulnerability index based on the sharp interface approach to predict the impacts of future climate change and groundwater depletion by anthropogenic activities. Morgan and Werner [15] combined the analytical approach with qualitative investigation to assess the vulnerability of confined aquifers in Australia.Recently, assessments using overlay and index techniques based on spatial mapping have been developed and improved to intuitively show the intrinsic vulnerability of aquifers. Some of the common methods used for classification and mapping of groundwater vulnerability zones include DRASTIC [16], GALDIT [17], SINTACS [18], and Aquifer Vulnerability Index (AVI) [19]. With the exception of GALDIT, the methods were developed from the concept that pollutants originate from the land surface and are transported through the vadose...

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Section: Galdit Indexing Of Parameters For Jeju Islandmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Application of GALDIT in Assessing the Seawater Intrusion Vulnerability of Jeju Island, South Korea

Chang

Chung

Kim

et al. 2019

Water

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“…Although GALDIT does not take into account the rate of groundwater withdrawal relative to the total amount of freshwater recharge to the aquifer, or the freshwater-saltwater interface in the seawater intrusion process, the simplicity of this method makes it attractive for assessing aquifer vulnerability to seawater intrusion (Ivkovic et al 2013), and it has been used for many coastal aquifer areas around the world (e.g. Chachadi et al 2003;Chachadi and Lobo-Ferreira 2007;Lobo-Ferreira et al 2007;Dörfliger et al 2011;Najib et al 2012;Kura et al 2015;Recinos et al 2015). According to the National Research Council (1993), vulnerability assessment methods must be evaluated in order to verify the assigned vulnerability rating and increase the reliability of assessments.…”

Section: Introductionmentioning

confidence: 99%

Comparison of the AVI, modified SINTACS and GALDIT vulnerability methods under future climate-change scenarios for a shallow low-lying coastal aquifer in southern Finland

2016

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A shallow unconfined low-lying coastal aquifer in southern Finland surrounded by the Baltic Sea is vulnerable to changes in groundwater recharge, sea-level rise and human activities. Assessment of the intrinsic vulnerability of groundwater under climate scenarios was performed for the aquifer area by utilising the results of a published study on the impacts of climate change on groundwater recharge and sea-level rise on groundwater-seawater interaction. Three intrinsic vulnerability mapping methods, the aquifer vulnerability index (AVI), a modified SINTACS and GALDIT, were applied and compared. According to the results, the degree of groundwater vulnerability is greatly impacted by seasonal variations in groundwater recharge during the year, and also varies depending on the climate-change variability in the long term. The groundwater is potentially highly vulnerable to contamination from sources on the ground surface during high groundwater recharge rates after snowmelt, while a high vulnerability to seawater intrusion could exist when there is a low groundwater recharge rate in dry season. The AVI results suggest that a change in the sea level will have an insignificant impact on groundwater vulnerability compared with the results from the modified SINTACS and GALDIT. The modified SINTACS method could be used as a guideline for the groundwater vulnerability assessment of glacial and deglacial deposits in inland aquifers, and in combination with GALDIT, it could provide a useful tool for assessing groundwater vulnerability to both contamination from sources on the ground surface and to seawater intrusion for shallow unconfined low-lying coastal aquifers under future climate-change conditions.

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“…It is believed that in this case, the effect of errors and uncertainties of a parameter is limited in the final output. Many previous researchers used this index to estimate vulnerability [16][17][18][19]. In the next step, arsenic and nitrate concentrations in groundwater were combined with the layers of groundwater recharge potential model, and an occurrence probability map was prepared.…”

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confidence: 99%

Assessing Pollution Risk in Ardabil Aquifer Groundwater of Iran with Arsenic and Nitrate Using the SINTACS Model

Dizaji¹,

Hosseini²,

Rezaverdinejad³

et al. 2020

Pol. J. Environ. Stud.

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Assessment of groundwater vulnerability to anthropogenic pollution and seawater intrusion in a small tropical island using index-based methods

Cited by 77 publications

References 43 publications

Application of GALDIT in Assessing the Seawater Intrusion Vulnerability of Jeju Island, South Korea

Application of GALDIT in Assessing the Seawater Intrusion Vulnerability of Jeju Island, South Korea

Comparison of the AVI, modified SINTACS and GALDIT vulnerability methods under future climate-change scenarios for a shallow low-lying coastal aquifer in southern Finland

Assessing Pollution Risk in Ardabil Aquifer Groundwater of Iran with Arsenic and Nitrate Using the SINTACS Model

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