Water quality assessment in terms of water quality index (WQI): case study of the Kolong River, Assam, India

Abstract

The Kolong River of Nagaon district, Assam has been facing serious degradation leading to its current moribund condition due to a drastic human intervention in the form of an embankment put across it near its takeoff point from the Brahmaputra River in the year 1964. The blockage of the river flow was adopted as a flood control measure to protect its riparian areas, especially the Nagaon town, from flood hazard. The river, once a blooming distributary of the mighty Brahmaputra, had high navigability and rich riparian biodiversity with a well established agriculturally productive watershed. However, the present status of Kolong River is highly wretched as a consequence of the post-dam effects thus leaving it as stagnant pools of polluted water with negligible socioeconomic and ecological value. The Central Pollution Control Board, in one of its report has placed the Kolong River among 275 most polluted rivers of India. Thus, this study is conducted to analyze the seasonal water quality status of the Kolong River in terms of water quality index (WQI). The WQI scores shows very poor to unsuitable quality of water samples in almost all the seven sampling sites along the Kolong River. The water quality is found to be most deteriorated during monsoon season with an average WQI value of 122.47 as compared to pre-monsoon and postmonsoon season having average WQI value of 85.73 and 80.75, respectively. Out of the seven sampling sites, Hatimura site (S1) and Nagaon Town site (S4) are observed to be the most polluted sites.

Water Quality Index of Waste Stabilisation Ponds and Downstream of Discharge Point

“…The results further indicate self-purification and natural processes occurred as wastewater travelled downstream of the discharge point. The results are comparable to the findings by[13] Water quality index of Site 2 as revealed by physiochemical parameters. Water quality index at Site 3 revealed by physiochemical parameters.…”

Spatial and Temporal Variations in Water Quality and Land Use in a Semi-Arid Catchment in Bolivia

“…In the present study, only the dry season was assessed due to the water quality decline during that season and to lack of data on the wet season, as noted in local reports [14][15][16]. Maximum concentrations of pollutants could thus be found in the dry season because of reduced precipitation and water flow volumes, therefore impeding the effects of natural dilution and self-purification capacity of the river [67].…”

Evaluation of Water Quality of Local Streams at Gandhamardan Iron Mines, Suakati, Keonjhar District of Odisha, India

“…These obtained data of fourteen parameters were compared with the standard guideline values, recommended by IS:2296. The obtained analytical data of fourteen physico-chemical parameters from six sampling stations are used for calculation of WQI in eq-1 [53] for different studied period to assess the suitability of water for drinking purposes, for irrigation purpose, for industrial purpose, for biotic communities etc. …”