Water quality index and GIS-based technique for assessment of groundwater quality in Wanaparthy watershed, Telangana, India

A comprehensive study of 58 groundwater samples collected in the virgin area of Wanaparthy watershed (1600 km2), Telangana, India, to assess the hydrochemistry, quality, water types and potability using hydrogeochemical characterization, WQI and GIS technique. Major ions concentration of Na+, K+, Ca2+, Mg2+, Cl−, F−, NO3− and SO42− in groundwater were analysed using ion chromatography (IC). Physicochemical values of the potential of hydrogen (pH), total dissolved solids (TDS) and electrical conductivity (EC) were determined using Hanna portable meters, while total hardness (TH), alkalinity and bicarbonates are estimated by titrimetric methods. Results obtained enlighten the major anions and cations, which are found in order of Cl− > HCO3− > SO42− > NO3− > F− and Na+ > Ca+2 > Mg+2 > K+ respectively. Among various ions measured, fluoride (18.97%), chloride (3.44%), nitrate (8.62%), sulphate (5.17%), sodium (34.48%) and calcium (1.72%) were found to above acceptable limit values of Bureau of Indian Standards (BIS) for drinking purposes. According to Piper trilinear diagram, two dominant hydrochemical facies, Na-Cl-SO4 and Ca-Na-HCO3 types, were identified. Gibbs diagram imparted the dominancy of samples in the territory are rock-water reaction and evaporation dominance. WQI shows 67.79% of samples pertain to the excellent to good water types reveal fit for drinking. Drainage pattern enumerated the concentration of the parameters measured are exceeding towards the downstream region, which might be due to the chemical reaction of rock-water interaction (infiltration and recharge). As the groundwater is the major source of drinking in the study area, a proper management plan has to implement before its quality deteriorated.