Vembanad Kayal is the largest lake in Kerala and is the longest lake in India. In the olden times it was used mainly for transportation, agriculture and farming. Today, it has become a major tourist attraction and is visited by tourists from all over the world. One of the things that attracted the tourists to this place is the backwater cruise in houseboats. Numerous houseboats with various facilities are available here. On their journey the tourists can enjoy the scenic beauty of the backwaters and the marine life forms that are present here. The marine and fresh water fishes include varieties like prawns, shrimps, crabs, karimeen etc.
The Vembanad ecosystem has a total area of about 1512 sq kms. It flows through three districts in Kerala namely Alappuzha, Kottayam and Ernakulam. Many canals are interconnected to Vembanad kayal and it lies at sea level separating the sea by a small island. The lake surrounds some islands like Pathiramanal, Perumbalam and Pallippuram. Some of the rivers that flow into this include Achenkovil, Manimala, Meenachil, Muvattupuzha, Pamba and Periyar.
An important feature of this lake is the Thanneermukkom salt water barrier. It has a length of about 1252 metres and was built to prevent the action of the tides and also to prevent the salt water from enter into the low lands of Kuttanad region. This barrier classifies the lake into two parts, one is the brackish water and the other is the fresh water. Yearly snake boat race is conducted in an extension of Vembanad kayal called as Punnamada Kayal and is also a main tourist attraction.