Healthy natural ecosystem is an indispensable prerequisite of a hale and hearty society. Although the socioeconomic, cultural as well as the political well-being of a region is directly correlated to a healthy and sustainable ecosystem, the mankind has relentlessly been tampering with these valued assets of nature for their comfort. Moreover, out of all the existing ecosystems it is a fact that aquatic ecosystem is the most imperiled one. Thus, it is the need of the hour to take some stern and state-of-the-art actions towards upholding the aquatic ecosystems of our environment. Like many other rivers of the world, the Kolong River of Assam is also going through a staid phase of degeneration as a result of human intervention, for the last half century. The objective of the present study is to reveal the ailing condition of the Kolong River along Nagaon town and to assess the change in the trend of its water quality parameters for a time interval of twenty years (i.e. 1992 to 2013). The results revealed that river discharge has diminished with time except for the peak monsoonal period. Similarly, few water quality parameters viz. Conductivity, total alkalinity, BOD, total hardness, calcium, magnesium and chloride has shown an increasing trend while pH, DO and phosphate evidenced a decreasing trend, which in turn highlighted the elevated level of pollution in the river. Thus, the temporal variations of water quality and hydrological variables have led to the escalating focus on work of river restoration and rejuvenation.
