Use of water quality index and DRASTIC index correlation for better assessment of groundwater vulnerability to pollution: a case study

DRASTIC method's vulnerability assessment for estimating the potential risk of contamination in shallow groundwater aquifers is the most acceptable technique. The method uses seven parameters, namely, depth to groundwater table, net recharge, aquifer media, soil media, topography, land use and land cover, and hydraulic conductivity to obtain vulnerability index values. These index values are validated with one or a few elements of water characteristics as pollution indicators. In most of the reported studies, the correlation coefficient between the DRASTIC index and the concentration of individual element(s) was low. The present study uses the water quality index (WQI) to correlate with the DRASTIC index value. In this paper, 11 physical and chemical water characteristics data of 31 well locations within the Faridabad District of Haryana, India are utilized to estimate the WQI. The correlation coefficients for single element concentration with DRASTIC index vary between the range of 0.104 to 0.304. The correlation coefficients for the concentration of NO3- and WQI are found to be 0.104 and 0.533, respectively. Thus, the DRASTIC index demonstrates a stronger correlation with the WQI when compared to single element concentration.