The Kerala backwaters are a network of interconnected canals, rivers, lakes and inlets, formed by more than 900 km of waterways. In the backwaters, freshwater from the rivers meets the seawater from the Arabian Sea, making a unique ecosystem.
In certain areas, such as the Vembanad Kayal or lake, barrages prevent the salt water from the sea from encroaching on the freshwater depths. The fresh water which is thus kept unsullied is used extensively for irrigation purposes. Vembanad Kayal, covering an area of 200 km, is the largest lake in the state. It is also the longest in India.
The beautiful town of Alappuzha, with its large network of canals, is known as the Venice of the East.