Ecological Health and the Economics of Water Quality: An Assessment of Kolong River, Assam, India

River health has become one of the most important environmental issues today because of multiple anthropogenic stressors and other artificial interventions that have led to adverse long-term impacts on the physical habitats, biodiversity, ecological functions and the services provided by a water body. Kolong river, located in Assam, India, has suffered a similar fate with it being listed among the 275 most polluted rivers of India by the Central Pollution Control Board, Government of India, in 2015. This study has been carried out with the primary objective of diagnosing chemical and biological river health of the Kolong river with regard to physico-chemical parameters and abundance of the plankton community, using statistical analysis. Four sites along the river were selected for sampling purposes, namely, Jakhalabandha (Station 1), Samoguri (Station 2), Nagaon town (Station 3) and Roha (Station 4). Thirteen physico-chemical parameters were considered for the study and data were collected month-wise for which results have been shown season-wise (pre-monsoon, monsoon, retreating monsoons and winter). Tests for physico-chemical parameters were done through standard methods. Means and standard deviations along with the Karl Pearson’s correlation coefficients were also calculated. Findings indicate significant relationships among the physico-chemical parameters as well as correlation of the abundance of phytoplankton and zooplankton with abiotic factors the river which was further computed by a regression analysis. Phytoplankton dominated over zooplankton in all the Stations in the present study. High abundance of Bacillariophyceae, in case of phytoplankton, and Copepods, in case of zooplankton, were encountered, indicating poor ecological health of the Kolong river. The study also involves a briefing on the economics of water quality and relevant economic strategies for managing ecological quality of Kolong. The study finally asserts on the need for minimising anthropogenic disturbances through both government and people participation, so as to manage pollution while preserving the ecological heath of the Kolong river.