Seasonal Study on the Assessment of Physico-Chemical Parameters of Narasapura Lake, Karnataka

Abstract

The present study was conducted to evaluate the seasonal variation of selected physico-chemical parameters in Narasapura Lake, Kolar, Karnataka, from January to December 2024. Key parameters analysed included pH, total alkalinity, total dissolved solids (TDS), magnesium, calcium, total hardness, iron, chloride, biochemical oxygen demand (BOD), and chemical oxygen demand (COD). The results revealed noticeable seasonal fluctuations in all parameters, primarily influenced by monsoon dynamics. The pH remained within the acceptable range (6.5–8.5) throughout the study period. Alkalinity and TDS showed higher values during pre-monsoon months and declined significantly during monsoon. Magnesium levels remained relatively stable. Calcium, total hardness, Iron and chloride exhibited higher concentrations during dry months and lower values during the monsoon season. BOD and COD values were higher during the initial months, indicating organic and chemical load, but showed a declining trend towards the end of the year, suggesting improvement in water quality. The variations in water quality were mainly attributed to natural factors such as rainfall, evaporation, and water inflow. However, results showed most parameters were within acceptable limits, with no significant pollution observed.