Grand Anaicut (Kallanai), Tiruchi, India

Visited in July 2022

We all know Kallanai (கல்லணை) in Tiruchi is a very ancient dam.

But, have we ever wondered if there are any other older dams in our planet? Here we go with the list of four oldest functional dams in the world in their chronological order of construction.

First in the list is Quatinah Barrage / Lake Homs Dam, Syria built by the Egyptian King Sethi (1319–1304 BC). That’s roughly 3300years before.

Second and third in the list are both in Spain-Proserpina Dam built between 1st or 2nd century AD and Cornalvo Dam claimed to be built around the same period as Proserpina. Cornalvo Dam is declared a UNESCO World Heritage Site.

And now comes proud moment. The fourth in the list of oldest functional dams is our own Kallanai built 1800 years before (2nd century AD) by the great visionary Chola King, Karikalan.

It was a perfect and spectacular sight to watch Grand Anaicut full to its brim and water gushing through the sluices flowing into Cauvery, Vennar and Kallanai canals- thanks to the recent monsoon rains in the vicinity of Thala Cauvery, the source of Cauvery, in Karnataka state.

Having visited the place and having read a few research papers/articles, I could understand that Kallanai basically is not a water storage dam but rather a water regulatory system.

Just to understand better, let’s get familiar with the physical map of river Cauvery. The island of Srirangam, lying approximately 10kms north of Tiruchi splits Cauvery into 2 rivers, one flows on the northern side and is named as Kollidam (Coleroon as referred by British) and the other retains the name Cauvery. Both the rivers continue to flow separately for around 20kms and finally meet at Kallanai. At this point, Kollidam is wider and steeper downstream with a higher water carrying capacity and Cauvery would naturally merge with Kollidam to reach the sea (Bay of Bengal) at PoomPuhar.

Karikala Cholan, the dynamic Chola king with a great foresight built a hydraulic structure using irregular stones (literally translates to Kallanai, Kal-stone and Anai-dam in tamil) across Cauvery river and harnessed water for irrigation which otherwise would wastefully empty into the ocean.

This 329 metres long innovative network of stone barrage constructed by Karikalan diverted the flow of Cauvery towards the more arid and water deprived Delta region. The barrage had a unique engineering design with a curving masonry and a irregular descent, probably conceived so as not to interrupt the natural flow/current of water thereby avoiding excessive silt and sedimentation in the process.

And this engineering marvel had a dual purpose too. In the event of any flood, the excess water would overflow the stone barrage into Kollidam-the flood carrying canal and the Delta region would continue to remain safe receiving its share of water for irrigation.

The story of this stupendous irrigation system does not end here. Karikalan went on to build many smaller canal networks and tanks along the course of the diverted river. The whole system evolved 1800 years before was capable of irrigating 70000 hectares of farmland in the Delta area thus transforming an otherwise barren land into a fertile region.

By building Kallanai, Karikalan had ensured the prosperity of his kingdom and paved the road for a dynamic and powerful dynasty to emerge and flourish for next 10 centuries winning wars, conquering territories and building the Great Chola temples later conferred with the World Heritage status.

In 1804, Captain Caldwell, a military engineer attached to the Colonial army raised the height of the barrage by few inches so as to divert more water to the Delta region. Major Sim proposed the idea of replacing the barrage with undersluices in 1829.

Sir Arthur Cotton, a renowned water system specialist with the Colonial government carried out Major Sim’s proposal of undersluices in 1830. He was also instrumental in building the Lower and Upper Anaicuts between 1836 and 1846 that enhanced the distribution network. He was so impressed with Kallanai that he adopted the same construction method and design in Upper Anaicut at Mukombu (20kms north-west of Tiruchi). The idea was deeply imprinted in his mind that he continued designing dams across river Godavari and Krishna (Andhra Pradesh) in the same lines as Kallanai in the later part of his tenure.

The Cauvery and Vennar Regulators built in 1886 and the Kallanai Canal in 1931 were useful additions by the Colonial administration strengthening Kallanai into a more robust water regulatory irrigation system and collectively referred to as Grand Anaicut as we see today. Thanks to the contribution of Sir Arthur Cotton and the Colonial government, today more than a million hectares of land in the Delta region stands to get benefited.

I dont think there exists any original structure built by Karikalan today. Do we really need one when the core concept is still alive and works exactly as it was intended by the great emperor Karikalan? No wonder, Delta region remains the ‘Granary of South India’ for the past 1800 years and would continue to do so.

Murugesan Krishnasamy

An alumni of  NIT,Trichy, living in Madurai-India, presently a freelancer and special volunteer in Madurai seed, a Madurai based NGO. Passionate about traveling – especially to off beat and historically significant destinations. Blessed with a compatible wife having identical interests. Writing travelogues is a spontaneous outcome of a dormant skill acknowledged and encouraged by friends.