Assessment of Surface Water Quality for Drinking by Combining Three Water Quality Indices with Their Usefulness: Case of Damodar River in India

Damodar River has been polluted due to human activities and the discharge of domestic and industrial wastewater. It is a possible source of water for nearby areas to meet the requirements. Therefore, the purpose of the research is to provide a clear representation of river water quality using different water quality indices together. To determine the class of water of this river, concentrations of 17 physico-chemical parameters have been compared with the standard limits prescribed by various organizations. These indicate that BOD, TC, and turbidity concentrations are high, and river water is fresh and moderately hard. Three indices like weighted arithmetic water quality index (WAWQI), Canadian Councils WQI (CCME-WQI), and comprehensive pollution index (CPI) are used together to determine the class of water with a higher level of confidence. To minimize the cost of parameter analysis, six parameters were eliminated using Pearson's correlation, and 11 parameters have been used to calculate three indices. Index scores with TC obtained by WAWQI, CCME-WQI, and CPI indicate unfit for drinking, poor category, and highly polluted water in this river, while three index scores without TC indicate fair to very poor water with slight pollution. To obtain water quality for every indicator, an in-depth analysis of rating scale estimates has been newly introduced because of the dissimilarity between the classification schemes of the applied methodologies. Final results and overall analysis confirm that the water is not suitable to drink. Water quality can be improved by TC control, and treatment is necessary before human consumption.