Water quality assessment of Kavvayi Lake of northern Kerala, India using CCME water quality index and biological water quality criteria

Assessment of water quality status of 7 sites of Kavvayi Wetland in northern Kerala (India) was carried out. The physico-chemical, bacteriological and biological parameters were monitored during pre-monsoon, monsoon and post-monsoon seasons. Canadian Council of Ministers of the Environment (CCME) water quality index of the Kavvayi Lake samples ranged from 43.99-44.77; indicating that water quality was threatened or impaired. The poor water quality status might be due to dumping of wastes from municipal and domestic sources and agricultural runoff. Biological water quality criteria (BWQC) determined for wetland revealed that stations such as mixing point of Kariangode River into Kavvayi Lake and Kottikkadavu was moderately polluted in pre-monsoon and post- monsoon seasons. Mixing point of Nileswar River into Kavvayi Lake was moderately polluted in pre-monsoon season. Both calculated indices suggest that quality of lake was found to be influenced by anthropogenic activities such as unscientific tourism and infrastructure development, land encroachment, sand mining, pollution etc. The study was carried out as part of a programme, which aimed to conserve Kavvayi wetland because of its unique ecological and environmental characteristics.