Adyar river starts from Malaipattu tank near Manimangalam village in Sriperumbudur Taluk at about west of Tambaram near Chennai. It starts to appear as a stream only from the point where water from Chembarambakkam lake joins the river. It flows through Kancheepuram, Tiruvallur and Chennai district for about before joining the Bay of Bengal in Adyar, Chennai. Here it forms an estuary, which extends from the Adyar Bridge to the sandbar at the edge of the sea, with some small islets in-between. The estuary attracts a wide variety of birds. The estuary covering an area of about was made a protected wildlife reserve in 1987. The river forms a backwater near the mouth, known as the Adyar creek, due to the formation of sand bar at the mouth. This creek is a natural channel which carries tidal water back into the sea.