Assessment of Cumulative Water Quality Index for River Cauvery and its Tributaries- Bhavani and Amaravathi in Tamil Nadu

This study evaluates the cumulative water quality index (CWQI) of river Cauvery and its tributaries, Bhavani and Amaravathi, in Tamil Nadu, India, to assess and monitor water quality over a decade (2011-2023). Water quality indices are essential for synthesizing complex datasets into a single number. The CWQI for river Cauvery and its tributaries – Bhavani and Amaravathi, was developed using 16 water quality parameters comprising physical, chemical and biological parameters based on Indian water quality standards. The CWQI is calculated by aggregating dimensionless sub-indices for each parameter, weighted according to their impact on water quality. Assessment was done by utilizing the National Water Quality Monitoring Programme data, covering 13 sampling locations. Results indicate that overall water quality has predominantly remained in the ‘good’ category, though localized fluctuations to ‘fair’ quality were observed, particularly in 2013 and subsequent years. These variations are attributed to domestic sewage, industrial discharges and agricultural runoff. To improve and maintain water quality, the study suggests a multifaceted approach, including stricter regulatory measures, enhanced community engagement and technological advancements in waste management and pollution control. The findings underscore the need for continuous monitoring and comprehensive management strategies to safeguard water quality in the Cauvery river basin.