Water Quality Index (WQI) Approach to Evaluate the Water Quality of Certain Tank Waters of Tiptur Taluk in Tumkur District, Karnataka, India

Evaluation of water quality using different parameters is complex and not easy to understand as it is variable by variable discussion. Water quality index is a single value indicator used to evaluate and present the water quality to the public and the related management in precise and understandable manner. Measured values of eleven physico-chemical parameters namely, pH, TDS, TH, Cl ,NO 3 ,SO4 2,HCO3 , Ca 2+ , Mg 2+ , Na + and K + were used to calculate WQI of six tanks in Tiptur taluk. The study was taken up to understand the impact of agriculture run off from the respective catchment area, domestic sewage input and human activities which contribute to pollution load. During the investigation period from December-2010 to November-2012, it was found that the overall water quality index of the studied tanks ranged from 46.72 to 92.22 indicating the quality ranging from good quality to very poor quality. Values of variables TDS, HCO3 , Na + and K + exceeded their desirable limits of BIS/ICMR in Karadi, Halkurke and Honnavalli tanks which depend on rain water. Waters in these tanks were of moderately poor to very poor quality. Waters of Canal fed tanks were of good to moderately poor quality.