GIS and Remote Sensing Based Spatio-Seasonal Assessment of Groundwater Quality in the Anjana Sub-Basin, Maharashtra, India

Abstract The groundwater is one of the principal sources of drinking and domestic water supply for the semi-arid regions of Maharashtra, and hence, the monitoring of groundwater quality is of utmost significance for the efficient management of water resources in the region. This study has been undertaken to evaluate the spatial and seasonal variation of groundwater quality in the GP-2 watershed of the Anjana sub-basin, located in the Chhatrapati Sambhajinagar district of Maharashtra, India, using hydro-chemical and GIS techniques. Groundwater samples were collected in the pre-monsoon and post-monsoon seasons of 2024, and the groundwater quality parameters such as pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), total alkalinity, chloride (Cl⁻), sulphate (SO₄²⁻), nitrate (NO₃⁻), fluoride (F⁻), calcium (Ca²⁺), magnesium (Mg²⁺), sodium (Na⁺), and potassium (K⁺) of the groundwater samples were analyzed using standard analytical procedures for all the fifty groundwater samples collected in the study area. Spatial distribution maps of all parameters were prepared using Inverse Distance Weighting Interpolation Method in GIS. From the results, it is observed that groundwater in the study area is of alkaline type with pH values of 8.01 and 7.77 in pre-monsoon and post-monsoon seasons, respectively. All parameters were within the permissible limits of Bureau of Indian Standards. TDS, hardness, and nitrate values were higher in certain areas of the study region. Calculated values of Water Quality Index (WQI) vary from 23 to 312 in pre-monsoon and 89 to 280 in post-monsoon seasons. From the values of WQI, it is observed that water quality of groundwater is ranging from excellent to unsuitable for drinking in certain areas of the study region. From this study, it is confirmed that water table recharge in pre-monsoon season affects groundwater water quality. Keywords: GIS, Remote sensing, Groundwater quality, GWQI, Anjana Sub-Basin