Kallanai (Grand Anicut)
Kallanai (Grand Anicut) is an ancient dam, which is built (in running water) across the Kaveri river in Tiruchirappalli District in the state of Tamil Nadu in India.
The dam was originally constructed by the Chola king Karikalan in 100 BC – 100 AD. It is located on Kaveri river approximately 20 KM from Trichy city, the dam falls under Thanjavur district.
The purpose of the Kallanai was to divert the waters of the Kaveri across the fertile delta region for irrigation via canals and to its northern delta branch Kollidam/Coleroon.
Down stream of the barrage, the river Kaveri splits into four streams known as Kollidam Aru, Kaviri, Vennaru and Puthu Aru. However, the flood waters can be allowed, by opening the barrage/anaicut gates, to pass through the other three delta branches also to join the sea.