Study of Groundwater Quality using GIS in Hirehalla Sub-basin of Koppal District, Karnataka, India

Abstract

Water quality problems were reported in the groundwaters of Hirehalla Sub-basin, Koppal district, Karnataka, India. 21 representative samples were collected and subjected to hydrochemical investigations. Major cations- Ca, Mg, Na, K and anions- CO₃, HCO₃, Cl, SO₄ were analysed. Physical parameters such as pH, EC, TDS, H were also determined. Piper hill trilinear diagram were plotted to study the hydrochemical characters of groundwater and it was found the groundwater to be of class- NaCl and CaMgCl type. Fluoride ion concentration was found to be in the range 0.26 to 6.42 mg/lit. Based on EC values it was found that 61% of water samples fall in excellent category. Drinking use suitability was determined by comparing the analysis results of water samples with BIS and WHO standards and it was found that 65% of the water samples are safe and fit for drinking purposes. Parameters like SAR and Na% were calculated to evaluate the suitability of waters for irrigational purposes. USSL and Wilcox diagram were plotted to determine agriculture suitability. It was found that 90% of the water samples are fit for irrigation. Different spatial variation maps were generated in GIS environs. Thus GIS based approach was efficient tool in assessment of water quality of Hirehalla Sub-basin.