Kallanai Dam is one of the oldest irrigation dams in the world built around 2000 years ago. It was built across the river Cauvery by the Chola King, Karikal Valavan.
The main purpose of building Kallanai was to divert the Cauvery water for irrigation in the Tanjavur delta. Kallanai has a strong foundation and solid structure. Due to its stubbornness it is still in excellent condition and is used as a major irrigation dam in Tamilnadu.
Kallanai has become model for many modern day dam constructions due to its strong engineering characters. Due to its engineering marvelous Sir Arthu Cotton studied this dam extensively before constructing the Kollidam Dam across the river Coloron a tributary of Cauvery.