Modification of GALDIT Model by using Entropy Method for Gharesoo-Gorgan Rood Coastal Aquifer Vulnerability Assessment

Document Type : Research Article

Authors

1 Msc in GIS/RS, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University, Tehran, Iran

2 Assistant Professor, Department of GIS/RS, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University, Tehran, Iran

3 Assistant Professor, Department of Irrigation and Drainage, Aburaihan Campus, University of Tehran, Iran

Abstract

It is highly important to identify vulnerable areas and protect groundwater resources in the  Gharesoo-GorganRood coastal aquifer due to the overexploitation of groundwater resources in this area. Therefore, in this study, the GALDIT model and Entropy method in GIS environment was used to evaluate the vulnerability of coastal aquifer. The parameters of the type of aquifer, the aquifer hydraulic conductivity, the height of groundwater above the sea level, distance from shoreline, the qualitative impact of seawater intrusion, and thickness of aquifer were used in the GALDIT model, which influence the assessment of coastal aquifer vulnerability. The maps were arranged in the form of six information layers using ArcGIS software. To more accurately assess the vulnerability, the weights of GALDIT parameters were modified using the entropy method, and GALDIT-Entropy vulnerability map was obtained. The correlation coefficient between the TDS parameter and vulnerability indices in the study area was used to obtain the optimal model. The correlation coefficient between GALDIT-Entropy model and TDS parameter was obtained 0.51, while the amount of this coefficient was 0.43 for GALDIT model. According to GALDIT-Entropy model, the northwest, southwest and west areas of aquifer have higher vulnerability to seawater intrusion. The map of this model is classified into four vulnerability classes of low, moderate, high, and very high which compose 14, 33, 30, and 23% of the study area, respectively. The GALDIT-Entropy model reduced the errors from expert opinions in the initial GALDIT. The proposed method can be used to assess vulnerability in the coastal aquifers with the same hydro-geological conditions.

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References

[1]. Gorgij A.D, Moghaddam A.A. Vulnerability Assessment of saltwater intrusion using simplified GAPDIT method: a case study of Azarshahr Plain Aquifer, East Azerbaijan, Iran. Arabian Journal of Geosciences. 2016; 9(2): 106.
[2]. Nadiri A.A, Sedghi Z, Kazemian N. Optimization of DRASTIC method using ANN to evaluating of vulnerability of multiple Varzqan aquifer. Iranian Journal of ECO Hydrology. 2018; 4(4): 1089-1103. [Persian]
[3]. Javanshir G, Nadiri A.A, Sadeghfam S, Novinpour E.A. Introducing a new method to aquifer vulnerability assessment of Moghan plain based on combination of DRASTIC, SINTACS and SI methods. Iranian Journal of ECO Hydrology. 2017; 3(4): 491-503. [Persian]
[4]. Neshat A, Pradhan B, Shafri HZM. An integrated GIS based statistical model to compute groundwater vulnerability index for decision maker in agricultural area. Journal of the Indian Society of Remote Sensing. 2014b; 42(4): 777-788.
[5]. Neshat A, Pradhan B. Evaluation of groundwater vulnerability to pollution using DRASTIC framework and GIS. Arabian Journal of Geosciences. 2017; 10(22), 501.
[6]. Neshat A, & Pradhan, B. An integrated DRASTIC model using frequency ratio and two new hybrid methods for groundwater vulnerability assessment. Natural Hazards. 2015; 76(1), 543-563.
 [7]. Neshat A, Pradhan B, Pirasteh S, Shafri HZM. Estimating groundwater vulnerability to pollution using a modified DRASTIC model in the Kerman agricultural area, Iran. Environmental Earth Sciences. 2014a; 71(7): 3119-3131.
[8]. Chachadi A.G, Lobo Ferreira JPC. Sea water intrusion vulnerability mapping of aquifers using the GALDIT method. 2001.
[9]. Gontara M, Allouche N, Jmal I, Bouri S. Sensitivity analysis for the GALDIT method based on the assessment of vulnerability to pollution in the northern Sfax coastal aquifer, Tunisia. Arabian Journal of Geosciences. 2016; 9(5): 416.
[10]. Mahrez B, Klebingat S, Houha B, Houria B. GIS-based GALDIT method for vulnerability assessment to seawater intrusion of the Quaternary coastal Collo aquifer (NE-Algeria). Arabian Journal of Geosciences. 2018; 11(4): 71.
[11]. Kardan Moghaddam H, Javadi S. Evaluation vulnerability coastal aquifer by GALDIT index and calibration by AHP method. Journal of water and soil conservation. 2016; 32(2): 163-177. [Persian]
[12]. Yu C, Zhang B, Yao Y, Meng F, Zheng C. A field demonstration of the entropy-weighted fuzzy DRASTIC method for groundwater vulnerability assessment. Hydrological sciences journal. 2012; 57(7): 1420-1432.
[13]. Sahoo M, Sahoo S, Dhar A, Pradhan B. Effectiveness evaluation of objective and subjective weighting methods for aquifer vulnerability assessment in urban context. Journal of Hydrology. 2016; 541, 1303-1315.
[14]. Chachadi AG. Seawater intrusion mapping using modified GALDIT indicator model-case study in Goa. JalvigyanSameeksha. 2005; 20: 29-45.
[15]. Shannon CE. A mathematical theory of communication. e Bell System Technical Journal. 1948; 27 (3): 379–423.
[16]. Li G.L, Fu Q. Grey relational analysis model based on weighted entropy and its application. In Wireless Communications, Networking and Mobile Computing, 2007. WiCom 2007. International Conference on (pp. 5500-5503). IEEE.
[17]. Wu J, Sun J, Liang L, Zha, Y. Determination of weights for ultimate cross efficiency using Shannon entropy. Expert Systems with Applications. 2011; 38(5), 5162-5165.
Iranian journal of Ecohydrology
Volume 6, Issue 1
April 2019
Pages 41-50

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History

  • Receive Date: 23 July 2018
  • Revise Date: 04 December 2018
  • Accept Date: 04 December 2018

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