STUDY OF WATER QUALITY AND DYNAMIC ANALYSIS OFPHYTOPLANKTONS IN FOUR FRESHWATER LAKES OF MYSORE, INDIA

Lakes in urban regions are ecological security zones and true indicators of sustainable urban development. They provide opportunities for recreation, study of local aquatic life and ornamental purposes. As a result of increasing land use conflicts and effluent disposal, water bodies and their catchments in the urban regions have been the real casualties. The lakes considered have their specific importance. Lingambudhi Lake was one of the major lakes in Mysore a few decades ago. However, because of development of housing colonies and overgrazing, this lake has lost it’s quality. Hinkal Lake has been a sewage disposal site for the surrounding Hinkal area. Due to lack of natural water, the Government has decided to convert it into commercial areas. Mandakalli Lake provides water for irrigation to the surrounding agricultural areas and is used for fishing purposes. But due to agricultural runoff and sewage inputs, this lake has undergone degradation over the years. Kukkarahalli Lake is a major lake and is used for ornamental and recreational purposes. However, the disposal of treated domestic wastewater has caused severe pollution in the lake. In order for the policy makers and general public to understand the extent of pollution in these lakes, water quality indices have been formulated. In this study, water quality indices which have been used are Canadian Council of Ministers of Environment (CCME) and National Sanitation Foundation (NSF). CCME provides information on quality for all designated purposes of a lake, while NSF provides the quality level, if the lake is being used, or is to be used for drinking purposes. One of the remarkable aspects of the lake environment is the large number of phytoplankton species that are present at any given time. Phytoplankton diversity in four lakes of Mysore has been discussed. Nine diversity indices have been derived using the PASTA soft ware program. An attempt has been made to correlate the presence and interactions of phytoplanktons and the variation of water quality parameters in the considered lakes