Pulicat lake bird sanctuary is a saline backwater lake. It is drained by Arni river while the Buckingham canal brings in the city’s drainage water. At the southern end is an opening on to Bay of Bengal through a shallow mouth of 200 m in width. The rest of the lake is closed by a sand bar running parallel to the Bay of Bengal in the form of the Sriharikota island.
The wetlands eco system are considered as among the richest areas of bio diversity. Pulicat, by virtue of the mixing of fresh water with sea water is found to be an ideal habitat for diverse life-forms. 160 species of fish, 25 species of polychaete worms, 12 species of prawn, 19 species of mollusk and 100 speceis of birds are well documented apart from a number of other aquatic flora and fauna.