The dam is constructed using unhewn stones laid directly into the riverbed without lime mortar.
It remains a functional hydraulic engineering marvel nearly 2,000 years after its original construction.
The structure served as the inspiration for the modern Delta Barrage in Egypt, which was designed by British engineer Sir Arthur Cotton.
The name 'Kallanai' translates literally from Tamil as 'Stone Dam'.
It was originally designed to distribute water across the fertile delta region to prevent floods and ensure year-round irrigation.
Grand Anaicut, also known as Kallanai, is an ancient dam built across the Kaveri River in the Thanjavur district of Tamil Nadu. Constructed by the Chola king Karikalan in the 2nd century AD, it is considered one of the oldest water-regulation structures in the world still in use. The dam was built using unhewn stone without mortar to divert river water for irrigation, demonstrating sophisticated hydraulic engineering for its time. It spans approximately 329 meters in length and 20 meters in width. The structure effectively splits the Kaveri into two, creating the Kollidam and the main Kaveri branch. Ongoing maintenance ensures its functionality for modern agricultural needs in the fertile Cauvery Delta. The site features a scenic park area surrounding the dam, popular for leisure strolls and river views.
The elevated viewing area at the park provides the best panoramic angle of the river division.
Bring a hat and sunscreen as there is very little natural shade on the dam structure.
Carry your own drinking water, as facilities on-site are limited.
Visit during the monsoon season or shortly after to see the dam at its highest water flow.
Do not attempt to walk on the uneven stones outside of designated paths, as the surfaces can be slippery and hazardous.
Maintain a respectful distance from the water's edge due to strong currents and uneven stonework.
