A Water Quality Assessment and Modelling of the Indian River Tungabhadra

Abstract

Every river gets polluted as it moves from its source to the end. Hence, the quality of the water requires investigation for the usability. In the present work 40.69 km stretch of the river Tungabhadra in the Davangere district of the Karnataka, India was chosen for testing the water quality. The samples’ physical, chemical and biological characteristics were tested from eight sites for each month during pre-monsoon, monsoon and post-monsoon seasons from 2017 to 2019. A biochemical oxygen demand-dissolved oxygen (BOD-DO) equation was estimated using the de-oxygenation and reaeration constants. The results showed that the physical and chemical parameters were within the limits of the usability standards for all the sampling stations during all seasons. For the first 2.54 km of the River Tungabhadra, the biochemical oxygen demand (BOD) levels were categorized as class “C”, implying the river water to be within drinking water standards. However, from 2.54 to 40.69 km stretch, the river was classified as class “D”, making it unsuitable for drinking water. It was also shown that the river could be maintained class “C” if it flowed at 6m3/s which can be achieved by releasing water from the Tunga and Bhadra reservoirs. Moreover, treatment of the municipal waste before spilling to the river would further reduce the BOD levels.