Kallainai is the oldest water diversion structure in the world built by the great king Karikala Chola in his period. It is situated in the place 15 km away from Trichy. Anaicut was built for the purpose of diverting the water of Caveri to various parts of delta region of Chola dynasty in ancient period. During flood, these waters destroy many small villages and civilians, so Karikalan planned this Kallanai and achieved it by his brilliant architectures in his ancient periods. Kallainai divides into 4 streams namely Caveri, Kollidam, Puthu Aaru and Vennaru.
Grand Anaicut is the name given by the British peoples who invaded India in late centuries as they are wondered about this marvelous construction. Captain Caldwell is a British engineer who researched this Kallanai, praised it for its structural construction and named it as The Grand Anaicut then it became a famous name. Kallanai constructed from stone spanning the Caveri with 1,079 ft long, 66 ft wide and 18 ft high. The dam is still in excellent condition and supplied a model to future engineers.
Sir Arthur Cotton made a tribute to this Anaicut by building a dam similar to Kallanai called The Lower Anaicut in the rivers of Kollidam in 19th century. This construction was made by him to avoid the slits underwater in the rivers of Kollidam. Due to the Kallanai, still the farmers of delta region are having their life in good conditions as it supplies sufficient amount of water and this Anaicut was also re-modeled in 19th century by increasing stones height to 0.69m.