Aquifer vulnerability assessment in the Bengal alluvial tract, India, using GIS based DRASTIC model

Abstract

In the present study, an attempt has been made to evaluate the aquifer vulnerability in the central part of Bengal alluvial tract, covering 5324 km 2 area by using DRASTIC model. Seven critical hydrogeological factors were taken into consideration. Initially, vulnerability index of individual factors were calculated on the basis of predefined weights and ratings. These indices were further combined to depict the actual vulnerability of the region. The model comprised of seven spatial parameters and their attributes and in handling of such diverse datasets, GIS played a significant role. For the depiction of the subsurface lithological characteristics, subsurface lotho-log data were used to generate 3 dimensional fence diagram of the entire region which was further helped in depicting the aquifer media condition. Entire eastern region of river Bhagirathi, a distributary of river Ganga, showed higher vulnerability index, which was about 29.65 % of the total study area, while the western portion had lesser vulnerability. Along with conventional modeling, map removal sensitivity analysis was also incorporated to examine the impact of different factors on the entire model. Depth to the water and impact of vadose zone were two important factors that contributed 46.93 % of the total variability of the model. Further, the generated model was incorporated with the locations of 156 groundwater samples, collected from the entire region and concentration of arsenic was determined to understand the probable relationship with the generated model through correlation coefficient. The model presented in the paper depicted recent hydrogeochemical condition of the aquifer which might help in further management of the region.

GIS-based DRASTIC and composite DRASTIC indices for assessing groundwater vulnerability in the Baghin aquifer, Kerman, Iran

“…4a and Table 6. As the gradient increases, the runoff increases as well (Israil et al, 2006), leading to less penetration (Jaiswal et al, 2003). According to Madrucci et al (2008), the gradients higher than 35 • are considered to be restrictions on groundwater desirability because of the lack of springs.…”

Contribution of the Sensitivity Analysis in Groundwater Vulnerability Assessing Using the DRASTIC and Composite DRASTIC Indexes

“…Net recharge is the amount of runoff that permeates to the Earth and reaches the groundwater surface (Singh et al, 2015;Ghosh and Kanchan, 2016). This research uses the Piscopo method (Chitsazan and Akhtari, 2009) to provide the net recharge layer for the Kerman-Baghin aquifer according to the following equation and Table 5:…”

“…Many studies have been conducted using DRASTIC index to estimate the groundwater vulnerability in the world different regions (Jaseela et al, 2016;Zghibi et al, 2016;Kardan Moghaddam et al, 2017;Kumar et al, 2016;Neshat and Pradhan, 2017;Souleymane and Tang, 2017;Ghosh and Kanchan, 2016;Saida et al, 2017), however, fewer studies have used the CDRASTIC index for evaluation of the groundwater vulnerability (Baghapour et al, 2016;Baghapour et al, 2014;Secunda et al, 1998;Jayasekera et al, 2011;Shirazi et al, 2012;Jayasekera et al, 2008). Boughriba et al (2010) utilized DRASTIC index in geographical information system environment for an estimate of the vulnerability in the aquifer.…”

Elemental composition of salt and vulnerability assessment of saline groundwater sources selected based on ethnoarchaeological evidence in Romania

“…Overall, the DRASTIC methodology, developed by the United States Environmental Protection Agency (US EPA), is a standardized approach for evaluating intrinsic groundwater pollution potential. The method is based on seven key hydrogeological settings: depth to groundwater (D) (Baghapour et al, 2016), net recharge (R) (Chitsazan and Akhtari, 2009;Ghosh and Kanchan, 2016), aquifer type (A) (Aller et al, 1985;Singh et al, 2015;Malakootian and Nozari, 2020), soil type (S) (Aller et al, 1985;Singh et al, 2015), topography/slope (T) (Aller et al, 1985;Malakootian and Nozari, 2020), impact of the vadose zone (I) (Shirazi et al, 2012;Singh et al, 2015;Malakootian and Nozari, 2020) and hydraulic conductivity (C) (Aller et al, 1985;Kardan Moghaddam et al, 2017;Neshat and Pradhan, 2017;Malakootian and Nozari, 2020). In the case of DRASTIC-LU index , the DRASTIC index is modified by adding the land use (LU) parameter as a new pollution potential factor (Malakootian and Nozari, 2020).…”