Surface water quality assessment of Ganga River Basin, India using index mapping

In this paper, an effort has been made to develop a methodology to integrate the Water quality index (WQI) with geographic information system (GIS) for an effective interpretation of the quality and health status of the Ganga River basin (GRB). GRB has been taken as a case study. The physical, chemical and biological analysis has been interpreted using WQI. Based on the results of the analyses, spatial distribution maps of selected water quality parameters were prepared using GIS platform. A significant degradation in the WQ of the stations located in the lower reaches of the river basin is observed. Allahabad is the most polluted station followed by Kanpur and Varanasi. The most inferior WQ with OIP value of 4.18 (polluted class) is observed in the pre-monsoon season of 2010 at Varanasi station. The OIP based on the individual index values was estimated giving the values in terms of pollution indices.