Assessing potability of groundwater using groundwater quality index (GWQI), entropy weighted groundwater pollution index (EGPI) and geospatial analysis for khambhat coastal region of Gujarat

Abstract

The Khambhat coastal region have intense agricultural and industrial activities and the region is highly vulnerable to contamination of groundwater, particularly due to salinization of groundwater resources. In this regard, the current study evaluates potability of groundwater in coastal villages of the Khambhat region, Gujarat, India. Chemical analysis of 57 groundwater samples was carried out to examine important potable water quality indicators. Weighted arithmetic groundwater quality index (GWQI) and Entropy weighed groundwater pollution index (EGPI) were evaluated to categorize the groundwater into different potable water quality and pollution zones. Furthermore, spatial maps were generated using various geospatial analysis to represent the geographic distribution of potable groundwater quality and groundwater pollution zones according to calculated GWQI and EGPI. The calculated average value of GWQI is 265.66, with the highest and lowest GWQI values being 479.57 and 93.45, respectively. GWQI values of 26.32% of samples were more than 300, indicating that the quality of groundwater is not acceptable as potable water. The calculated values of EGPI are from 0.8 to 4.13, with an average value of 2.35, which reflects that more than 66% of groundwater samples are very high to extremely high polluted category.