Developing a Pollution Assessment Model for East-Flowing Rivers of Deccan Volcanic Province of India

Rapid urbanization and industrialization have significantly degraded river water quality, impacting ecosystems and human health. In the Indian peninsular region, most east-flowing rivers originate in heavy rainfall regions of the Western Ghats and flow throughout semi-arid areas before draining into the Bay of Bengal through major river systems like the Godavari and Krishna. Anthropogenic activities are among major threats to river health. This study focuses on assessment of water quality across the Indrayani River basin, as a representative of the east-flowing rivers of the Deccan Volcanic Province (DVP), to map pollution levels throughout the basin. Sampling was carried out at specific locations to ensure that all significant pollution sources and land use patterns are covered. Both point and non-point sources of pollution and their impact on the river system were analysed. Results show that electrical conductivity (EC), total hardness (TH) and chloride (Cl) levels exceed permissible limits at many locations in downstream sites. A notable increase in phosphate (PO4) concentrations was observed at several locations, primarily due to widespread use of household detergents. The water type is identified as Ca-Mg-Cl-SO4, with rock-water interactions playing a dominant role in the water quality. Additionally, pollution due to river water intrusion in aquifers and vice versa was studied, considering the topography. The study concluded by suggesting that decentralized water quality assessments at sub-basin and micro-watershed levels will be helpful in developing effective pollution control strategies and pollution abatement models for the east-flowing rivers of the DVP.