Vol. 9, Special Issue 6, Part G (2025)

Lingambudhi and Mandakahalli waterbodies are major lakes in Mysore. A few decades ago, Lingambudhi lake has lost its quality, because of development of housing colonies and overgrazing. Mandakahalli lake provides water for irrigation to the surrounding agricultural areas and it is used for fishing purposes. Recently the agricultural runoff and sewage inputs into the lake has led to degradation. Water quality index (WQI) was calculated by taking ten physico-chemical parameters and dynamic analysis of Phytoplankton diversity in these two lakes of Mysore has been discussed. Nine diversity indices have been derived using the PASTA software programme. A total of 29 algal species have been identified. An attempt has been made to correlate, the interaction of phytoplankton and the variation of water quality parameters in the selected lakes of Mysore. The values are above the upper limits in terms of WQI, which indicated that the water was not safe for human use. Both the water bodies were low in dissolved oxygen and least abundance of plankton indicate negative inferences. The WQI and diversity of Phytoplankton is widely used to evaluate and solve the problems of failures of management strategies for improving water quality of the polluted waterbodies.