Kallanai (also known as the Grand Anicut) is an ancient dam built by Karikala of Chola dynasty in 150 CE.
In 1804, Captain Caldwell, a military engineer, was appointed by the British to make a study on the Kaveri river and promote irrigation for the delta region.
[8] He found that a large amount of water passed onto the Kollidam leaving behind a small volume for irrigation purposes.
[3] The Lower Anaicut built by Sir Arthur Cotton in the 19th century across Coleroon, the major tributary of Cauvery is said to be a replicated structure of Kallanai.
The northern channel is called the Kollidam (Coleroon); the other retains the name Kaveri, and empties into the Bay of Bengal at Poompuhar.