Journal of Advances in Biology & Biotechnology

Freshwater resources are indispensable for domestic, agricultural, and industrial uses; however, rapid urbanisation, industrialisation, and population growth have led to significant deterioration in lake water quality worldwide. The Water Quality Index (WQI) has emerged as a reliable and integrative tool for evaluating physico-chemical parameters and determining the suitability of water bodies for human use and ecological sustainability. The present study evaluated the water quality of Mamadapur Lake located in Babaleshwar taluk of Vijayapuraa district, Karnataka, for drinking purpose using Water Quality Index. Surface water samples were collected at monthly intervals from July 2024 to June 2025 and analyzed for major physicochemical parameters. The mean pH value was 7.51±0.42, indicating a slightly alkaline nature within the permissible range of 6.5 to 8.5. Dissolved oxygen varied from 4.1 to 6.3 mg/L with an average of 5.33±1.56 mg/L. Biological oxygen demand ranged between 1.9 and 5.12 mg/L with a mean value of 3.12±2.28 mg/L. Chemical oxygen demand fluctuated from 19 to 23 mg per L. The average alkalinity and hardness were 96.14 mg/L and 106.15 mg/L, respectively. Total dissolved solids and total suspended solids recorded mean values of 223 mg/L and 34 mg/L, both within acceptable limits. Nitrate concentration remained low, averaging 0.17±0.12 mg/L. The overall Water Quality Index was calculated as 95.12, indicating excellent water quality. The results confirm that the lake water is suitable for drinking and domestic purposes.