It is located 60-km away from Vijayawada near Eluru, West Godavari district. It is the largest fresh Water Lake in the country. This sanctuary extends over 673-sq-km (depending on water spread) of wetland and marshes surrounding the Kolleru Lake, between the Krishna and Godavari deltas. It is described as "Peerless Fisherman's Paradise and Birds heaven" in the Imperial Gazetteer. It receives water from four rivers, namely Budameru, Ramileru, Tammileru and Yerrakalva and 18 drains. This lake empties its water into the Bay of Bengal, every 6 months through an outlet called 'Upputera'.
The flora mainly consists of aquatic weeds like Ipomea Aquatics, Scirpus, Water Hyacinth, Phragmites, Ottelia, Typha etc. and certain tree species like Babul, Albezzia, Rain tree, Palmyrah, Prosopis and coconut trees.
A Pelican Haven :
This lake supports a rich biodiversity and high biomass of fish, plankton that forms the source of food for birds. Pelicans arrive here during the nesting season to raise their young. In winter great activity can be seen here. The babble of Pelicans can be heard a quarter of a mile away. Apart from pelicans, one can find grey herons, white ibis, pond herons, egrets and many migratory ducks and water birds.
The Aquatic Life :
Invertebrates like Crustaceans and Molluscs and 63 species of fish belonging to 29 families are found in the lake. Main ones are Boccha, Valugah, Korameenu, Gurak, Bangaru Teega, Jella, Ingilayh and Bommidayalu. Ingilayh and Bommidayalu are two species, which are under threat of extinction.
Birds like Teals and Pintails are the main species. Other species include painted storks, open bill storks, grey Herons, cormorants, white Ibises, glossy Ibises, egrets, Reef Herons, Ducks, Coots, Shovellers, Terns, Jacanas, Moorhens etc can be seen here.