Kallanai is also known as the “Grand Anicut”. It is one of the oldest irrigation dams in the world built around 2000 years ago. It is the world ancient first dam which is built (In running water) across the Kaveri River in Trichy District in the state of Tamil Nadu
The dam was originally constructed by the ‘Chola king Karikalan’ around the 2nd Century AD and is considered to be one of the oldest water-diversion or water-regulator structures in the world
The dam was constructed in a elegant way to see the dam from any point. The dam is about 329 m (1,079 ft) long, 20 m (66 ft) wide and 5.4 m (18ft) high. The Kaveri River splits into two at a point 20 miles (32 km) west of Kallanai. The two rivers form the island of Srirangam before joining at Kallanai.
The northern channel is called the Kollidam (Coleroon). The Kollidam river spilts the formation of silt. The other retains the name Kaveri, and empties into the Bay of Bengal at Poompuhar. On the seaside face of its delta are the seaports of Nagapattinam and Karaikal.
The main purpose of the Kallanai dam was to divert the waters of the Kaveri across the fertile delta region for irrigation via canals. The dam splits the river Kaveri into 4 streams known as Kollidam Aru, Kaveri, Vennaru and Puthu Aru.
