scholarly journals GROUNDWATER VULNERABILITY ASSESSMENT TO SEAWATER INTRUSION THROUGH GIS - BASED GALDIT METHOD. CASE STUDY: ATALANTI COASTAL AQUIFER, CENTRAL GREECE

2017 ◽  
Vol 50 (2) ◽  
pp. 798 ◽  
Author(s):  
I. Lappas ◽  
A. Kallioras ◽  
F. Pliakas ◽  
Th. Rondogianni
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifer ◽  
Groundwater Resources ◽  
Groundwater Vulnerability ◽  
Aquifer Vulnerability ◽  
Hydrogeological Parameters ◽  
Groundwater Occurrence ◽  
Boundary Parameter ◽  
Groundwater Vulnerability Assessment ◽  
Galdit Method

Groundwater resources assessment has resulted in development of models that help identify the vulnerable zones. This paper presents a GIS-based hydrogeological index, named GALDIT, aiming at the assessment of aquifer vulnerability to seawater intrusion in Atalanti coastal aquifer, Central-Eastern Greece. The above acronym is formed from the most important factors controlling seawater intrusion, that is, four intrinsic hydrogeological parameters, one spatial parameter and one boundary parameter including Groundwater occurrence (aquifer type), Aquifer hydraulic conductivity, depth to groundwater Level above the sea (hydraulic head), Distance from the shore, Impact of seawater intrusion and aquifer’s Thickness. These factors nclude the basic requirements needed to assess the general salinization potential of each hydrogeological setting. Each parameter is evaluated with respect to the other to determine the relative importance of each factor. GALDIT model is described to assess and quantify the significance of vulnerability to seawater intrusion due to excessive groundwater withdrawals. Different thematic maps are prepared for seawater intrusion indicators and overlaid to develop the final vulnerability map. The derived map can be used as a tool for coastal groundwater resources management and areas’ determination of potential saltwater intrusion since the result of GALDIT ndex is classified based on vulnerability rate.

scholarly journals Assessing groundwater vulnerability to sea water intrusion in the coastline of the inner Puck Bay using GALDIT method

2018 ◽  
Vol 54 ◽  
pp. 00023 ◽  
Author(s):  
Dawid Potrykus ◽  
Anna Gumuła-Kawęcka ◽  
Beata Jaworska-Szulc ◽  
Małgorzata Pruszkowska-Caceres ◽  
Adam Szymkiewicz ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Seawater Intrusion ◽  
Sea Water ◽  
Groundwater Vulnerability ◽  
Aquifer Vulnerability ◽  
Galdit Method ◽  
The Impact ◽  
Simulated Scenario ◽  
Puck Bay

In this research, GALDIT method was used to assess seawater intrusion in the coastal aquifer of the inner Puck Bay (Southern Baltic Sea). The impact of potential sea-level rise on groundwater vulnerability for years 2081-2100 was also considered. The study area was categorized into three classes of vulnerability: low, moderate and high. The most vulnerable area is the Hel Peninsula with northern part of the Kashubian Coastland. Increased class of aquifer vulnerability is also adopted to glacial valleys. The results of this research revealed that about 18.9% of the analyzed area is highly vulnerable to seawater intrusion, 25.3% is moderately vulnerable and 55.8% is potentially at low risk. The simulated scenario of predicted sea level rise shows enlargement of high vulnerability areas.

scholarly journals Development of monthly seawater intrusion vulnerability assessment method using GALDIT

2021 ◽  
Author(s):  
Il hwan Kim ◽  
IL-Moon Chung ◽  
Sun Woo Chang
Keyword(s):  
Sea Level ◽  
Seawater Intrusion ◽  
Groundwater Level ◽  
Groundwater Resources ◽  
Assessment Method ◽  
Coastal Areas ◽  
Dynamic Parameters ◽  
Groundwater Occurrence ◽  
Monthly Changes ◽  
Galdit Method

Accurate diagnoses of vulnerability of seawater intrusion (SWI) into aquifers are required to ensure sustainable utilization of groundwater resources in coastal areas. GALDIT was selected to assess the SWI vulnerability on western coastal areas of South Korea. Climate change trends are updated every year. The existing GALDIT method has various scores to express the changing observed values. However, they are limited because of their sensitivity in the assessment of regional characteristics or climatic change due to low weight flexibility. Therefore, this study assessed vulnerability to SWI by classifying the existing GALDIT into static and dynamic parameters. The static parameters include groundwater occurrence (G), aquifer hydraulic conductivity (A), and distance from the shore (D), whereas the dynamic parameters include height to groundwater level above sea level (L), impact of existing status of seawater intrusion (I), and aquifer thickness (T). The monthly mean was used as the dynamic index to reflect monthly variations. To indicate the temporal trend of parameter L was calculated based on the data observed at the sea level station adjacent to the groundwater level station. To sensitively reflect the monthly changes in values, the range of scores was divided into 10 parts. The calculated GALDIT index showed that the most vulnerable month was September. In the progress of SWI, vulnerability was assessed monthly to highlight the differences in parameters that fluctuate seasonally. The proposed method can be used to apply intensive countermeasures to vulnerable sites and build an operation plan considering the vulnerability period.

Assessing Coastal Aquifer to Seawater Intrusion: Application of the GALDIT Method to the Cuddalore Aquifer, India

2019 ◽  
pp. 233-250 ◽  
Author(s):  
Subbarayan Saravanan ◽  
K.S.S. Parthasarathy ◽  
S. Sivaranjani
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifer ◽  
Galdit Method

scholarly journals GROUNDWATER VULNERABILITY ASSESSMENT USING DRASTIC MODEL OF UP AL-KHASSA DAM SUB-BASIN, KIRKUK, NE IRAQ

2020 ◽  
Vol 53 (2E) ◽  
pp. 12-24
Author(s):  
Madyan Al-Gburi
Keyword(s):  
Vulnerability Assessment ◽  
Groundwater Vulnerability ◽  
Aquifer Vulnerability ◽  
Drastic Model ◽  
Drastic Method ◽  
Groundwater Vulnerability Assessment ◽  
Arc Gis ◽  
Vulnerability Map ◽  
Gis Software ◽  
Program Version

Several studies and assessments have been conducted of areas exposed to pollution, especially areas that contain aquifer. The final extraction of the vulnerability map of the groundwater was constructed through the use of the DRASTIC method by applying the linear equation of the seven coefficients in the Arc GIS software program (Version 10.4). The aim of the study to assess aquifer vulnerability to pollution. Results, vulnerability map range between 75-126 (very low, low, and medium), the study area consists of very low and low vulnerability, except some areas medium vulnerability close to the center of the sub-basin in the standard vulnerability map (s) and 91-149 (very low, low, and medium) for the agriculture or pesticide vulnerability map (p), the medium vulnerability occupies a greater area the center of the sub-basin.

scholarly journals Proposing the Optimum Withdrawing Scenarios to Provide the Western Coastal Area of Port Said, Egypt, with Sufficient Groundwater with Less Salinity

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3359
Author(s):  
Mohamed Abdelfattah ◽  
Heba Abdel-Aziz Abu-Bakr ◽  
Ahmed Gaber ◽  
Mohamed H. Geriesh ◽  
Ashraf Y. Elnaggar ◽  
...  
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifer ◽  
Sustainable Management ◽  
Groundwater Resources ◽  
Field Investigation ◽  
Visual Modflow ◽  
Groundwater Abstraction ◽  
Human Needs ◽  
Western Area ◽  
Port Said

Recently, groundwater resources in Egypt have become one of the important sources to meet human needs and activities, especially in coastal areas such as the western area of Port Said, where seawater desalination cannot be used due to the problem of oil spill and the reliance upon groundwater resources. Thus, the purpose of the study is the sustainable management of the groundwater resources in the coastal aquifer entailing groundwater abstraction. In this regard, the Visual MODFLOW and SEAWAT codes were used to simulate groundwater flow and seawater intrusion in the study area for 50 years (from 2018 to 2068) to predict the drawdown, as well as the salinity distribution due to the pumping of the wells on the groundwater coastal aquifer based on field investigation data and numerical modelling. Different well scenarios were used, such as the change in well abstraction rate, the different numbers of abstraction wells, the spacing between the abstraction wells and the change in screen depth in abstraction. The recommended scenarios were selected after comparing the predicted drawdown and salinity results for each scenario to minimize the seawater intrusion and preserve these resources from degradation.

Aquifer vulnerability and seawater intrusion risk using GALDIT, GQISWI and GIS: case of a coastal aquifer in Tunisia

2016 ◽  
Vol 75 (8) ◽  
Author(s):  
Nadia Trabelsi ◽  
Ibtissem Triki ◽  
Imen Hentati ◽  
Moncef Zairi
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifer ◽  
Aquifer Vulnerability

scholarly journals A GIS-based Modified DRASTIC (ANP) method for assessment of groundwater vulnerability: a case study of Nagpur city, India

2015 ◽  
Vol 52 (2) ◽  
pp. 121-135 ◽  
Author(s):  
Sahajpreet Kaur Garewal ◽  
Avinash D. Vasudeo ◽  
Vishrut S. Landge ◽  
Aniruddha D. Ghare
Keyword(s):  
Nitrate Concentration ◽  
Groundwater Resources ◽  
Groundwater Vulnerability ◽  
Geographical Information ◽  
Network Process ◽  
Groundwater Vulnerability Assessment ◽  
Modified Drastic ◽  
Gis Environment ◽  
Sensitive Parameters ◽  
Vulnerable Zones

Quality of groundwater is as important as quantity. For effective planning and management of groundwater resources, groundwater vulnerability assessment is most significant. The objective of the present study was to evaluate the groundwater vulnerable zones of Nagpur city, using Modified DRASTIC methods within a Geographical Information System (GIS) environment. DRASTIC method has been modified using land use/land cover parameter; weight of the parameters was modified using Analytical Hierarchy Process (AHP) and Analytical Network Process (ANP). Sensitivity analysis has been carried out to consider the most sensitive parameters. A new approach ANP was applied on DRASTIC for the first time to modify the weight of the parameters. Groundwater vulnerable zones obtained from the DRASTIC, Modified DRASTIC, Modified DRASTIC AHP and Modified DRASTIC ANP were compared and validated using field data of nitrate concentration. Results obtained from the Modified DRASTIC ANP are found to be well correlated with the nitrate concentration of the city and it is appropriate for assessment of groundwater vulnerable zones of Nagpur city. From this study it was found that the necessary remedial measures should be taken in the highly vulnerable zones of Nagpur city for further prevention of groundwater pollution.

scholarly journals An Evaluation of Groundwater Vulnerability Assessment Methods in a Rapidly Urbanizing City: Evidence From Dakar, Senegal

2021 ◽  
Author(s):  
Abdoulaye Pouye ◽  
Seynabou Cissé Faye ◽  
Mathias Diedhiou ◽  
Cheikh Becaye Gaye ◽  
Richard G. Taylor
Keyword(s):  
Land Use ◽  
Groundwater Quality ◽  
Low Income ◽  
Groundwater Vulnerability ◽  
Unconfined Aquifer ◽  
Aquifer Vulnerability ◽  
Near Surface ◽  
Nitrate Concentrations ◽  
Groundwater Vulnerability Assessment ◽  
The Tropics

Abstract In rapidly growing cities in the tropics, unregulated urban development presents a major risk to groundwater quality. Here, we assess the vulnerability of an unconfined aquifer of Quaternary sands in the Thiaroye area of Dakar (Senegal) to contamination using four GIS-based indices (DRASTIC, DRASTIC_N, SINTACS, SI). Our correlation of assessed vulnerability to observed impact is semi-quantitative, relating observed groundwater quality, based on nitrate concentrations and tryptophan-like fluorescence to vulnerability degrees (i.e. coincidence rates). We show that considerably more of the Thiaroye area has a “very high vulnerability” according to SI (36%) relative to DRASTIC (5%) and SINTACS (9%); “high vulnerability” is estimated using DRASTIC_N (100%), DRASTIC (66%) and SINTACS (69%). Single-parameter sensitivity tests show that groundwater depth, soil, topography, land use and redox parameters strongly influence assessments of groundwater vulnerability. Correlation with observed nitrate concentrations reveals aquifer vulnerability is better represented by SI (coincidence rates of 56%) relative to DRASTIC_N (43%), SINTACS (38%) and DRASTIC (34%). The underestimation of groundwater vulnerability in Dakar using DRASTIC, DRASTIC_N and SINTACS is attributed to their reliance on an assumed capacity of the unsaturated zone to attenuate surface or near-surface contaminant loading, which in the low-income (Thiaroye) area of Dakar is thin and affords limited protection. The inclusion of a land-use parameter in SI improves the characterization of groundwater vulnerability in this low-income, rapidly urbanizing area of Dakar.

scholarly journals The variation of stygofauna along a gradient of salinization in a coastal aquifer

2015 ◽  
Vol 47 (1) ◽  
pp. 89-103 ◽  
Author(s):  
M. Shapouri ◽  
L. Cancela da Fonseca ◽  
S. Iepure ◽  
T. Stigter ◽  
L. Ribeiro ◽  
...  
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifer ◽  
Salinity Gradient ◽  
Groundwater Resources ◽  
Groundwater Salinity ◽  
Low Salinity ◽  
Composition And Structure ◽  
Shallow Wells ◽  
Southern Portugal ◽  
Highly Correlated

We examined the variation of stygofauna composition collected in wells, along a gradient in groundwater salinity/conductivity in a coastal aquifer from southern Portugal. The studied coastal aquifer is considered vulnerable to salinization due to seawater intrusion, caused by overexploitation of the aquifer. Knowing the response of the stygofauna species to present levels of groundwater salinity makes it possible to understand and measure the effects of saltwater intrusion on stygofauna, rendering them potential bioindicators of this environmental pressure. Biotic and abiotic sampling was conducted in six shallow wells located in the fresh–saltwater interface of the Arade estuary along the salinity gradient established in the groundwater from the estuary to inland locations (microSiemens/cm). Groundwater salinity was highly correlated with taxa distribution. The stygobites Eucyclops hadjebensis and Acanthocyclops sensitivus, the cosmopolitan Megacyclops viridis and Cypria ophtalmica were particularly associated with low-salinity conditions, whereas Eucyclops graeteri, Megacyclops brachypus and Daphnia pulicaria were related to high-salinity waters. Multivariate analyses indicated that stygofauna assemblages varied significantly with location. We suggest that stygofauna composition and structure can be a useful complementing tool for monitoring seawater intrusion into coastal aquifers, where reduction or deterioration in groundwater resources is predicted.

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