Evaluation of Groundwater Suitability for Drinking Purposes Using GIS and WQI in Chikkaballapura Taluk, Karnataka, India

In the present study, groundwater samples were analysed to determine the suitability of groundwater for drinking use in Chikkaballapura taluk (CBT) in 2019. The tests were conducted on the groundwater twice a year, during the pre-monsoon and post-monsoon seasons. The results of 12 physico chemical parameters were used for the calculation of the water quality index (WQI). ArcGIS was used in the study to plot the spatial variation of chloride, nitrate, and fluoride. In urban areas, WQI ranged from 42.94 to 204 during the pre-monsoon season and from 62.67 to 153.93 during the post-monsoon season. Similarly, in rural areas, WQI ranged from 47.78 to 245.98 during the pre-monsoon season and from 35.92 to 405.63 during the post-monsoon season. The results of the WQI show that most samples fall into poor water categories according to the quality rating scale. Also, the results revealed that both in Chikkaballapura rural (CBR) and Chikkaballapura urban (CBU), most of the groundwater samples exceeded the drinking water quality limits during the pre-monsoon season when compared to the post-monsoon season. High levels of fluoride were found in Thippanahalli, Doddapailagurki, Poshettihalli, Kuppahalli, Mandikal and Ajjivara grama panchayaths and a significantly high concentration of nitrate was found in Addagallu and Manchanabele grama panchayaths during the pre-monsoon season in CBR. It was suggested that constant monitoring of groundwater quality in contaminated areas be carried out to prevent further deterioration and related problems and that rainwater harvesting practices be encouraged to help reduce the load on urban and rural water supply systems.