| Kallanai Dam | |
|---|---|
.jpg) Kallanai Dam with its floodgates open | |
 Interactive map of Kallanai Dam | |
| Location | Thanjavurdistrict, Tamil Nadu, India |
| Purpose | Irrigation |
| Status | Operational |
| Construction began | c.150 BC |
| Built by | Karikala cholan ofChola dynasty |
| Operator | Government of Tamil Nadu |
| Dam and spillways | |
| Type of dam | Barrage |
| Impounds | River |
| Height (foundation) | 5.4 metres (18 ft) |
| Length | 329 metres (1,079 ft) |
| Width (base) | 20 metres (66 ft) |
Kallanai (literally “stone dam”, also known as theGrand Anicut) is an ancientdam built byKarikala ofChola dynasty in 150 CE. It was built (in running water) across theKaveri river flowing fromTiruchirapalli District toThanjavur district,Tamil Nadu,India. The dam is located in Thanjavur district,[1][2][3] 15 km fromTiruchirapalli and 45 km fromThanjavur.[4][5][6] It is the fourth oldest water-diversion or water-regulator structure in the world and the oldest in India that is still in use.[7][8]
The dam was originally built by KingKarikalan of the Chola Dynasty inc. 100 – c. 150 CE. It is located on the river inThanjavur district,[1] exactly 14 km from the city ofTiruchirappalli and 45 km from the city of Thanjavur. The idea behind the construction of the dam was to divert the river to thedelta districts thereby boosting irrigation.[4][5][6] This dam was re-modeled by theBritish during the 19th century. In 1804, Captain Caldwell, a military engineer, was appointed by the British to make a study on the Kaveri river and promote irrigation for the delta region.[9] He found that a large amount of water passed onto the Kollidam leaving behind a small volume for irrigation purposes.[9] Caldwell initially proposed a solution by raising the dam and hence raised the dam stones to a height of 69 centimetres (27 in), thus increasing the capacity of the dam.[4] Following this, Major Sim proposed the idea ofundersluices across the river with outlets leading to theKollidam River (Coleroon) thus preventing formation of silt.[4] TheLower Anaicut built bySir Arthur Cotton in the 19th century across Coleroon, the major tributary of Cauvery is said to be a replicated structure of Kallanai.[4]
TheKaveri river splits into two at a point 20 miles (32 km) west of Kallanai. The two rivers form theisland of Srirangam before joining at Kallanai. The northern channel is called theKollidam (Coleroon); the other retains the name Kaveri, and empties into theBay of Bengal atPoompuhar. On the seaward face of its delta are the seaports ofNagapattinam andKaraikal.[10]
The purpose of the Kallanai was to divert the waters of the Kaveri across the fertiledelta region for irrigation via canals and to its northern delta branch Kollidam/Coleroon. Downstream of the barrage, the river Kaveri splits into four streams known as Kollidam Aru, Kaveri, Vennaru andPuthu Aru. However, the flood waters can be allowed, by opening the barrage/anaicut gates, to pass through the other three delta branches also to join the sea.[11] It is constructed from unhewn stone spanning the Kaveri and is 329 m (1,079 ft) long, 20 m (66 ft) wide and 5.4 m (18 ft) high.[12] The dam is still in excellent condition, and supplied a model to later engineers, including SirArthur Cotton's 19th-century dam across the Kollidam, the major distributary of the Kaveri.[13] The area irrigated by the ancient irrigation network is about 69,000 acres (28,000 ha). By the early 20th century, the irrigated area had been increased to about one million acres (400,000 ha).[14]
The delta farmers of Tamil Nadu have demanded the Tamil Nadu government to honorKarikala Cholan, who built this dam.[15]
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