Kolleru Lake is the largest natural freshwater lake in the districts of East and West Godavari of Andhra Pradesh. The major population centres in the Kolleru Lake region are the 148 villages of which 50 bed villages and 98 belt villages. All bed and belt villages in lake region have atleast one drinking water pond.
Indian Journal of Environmental Health
On the basis of hydrochemical and biological studies, a trophic gradient has been established between the inshore and the offshore areas of the Dal lake. The inshore areas receive large quantities of raw sewage and agricultural runoff as a result of which high nutrient concentration of water and the presence of dense phytoplankton populations have been registered at these sites.