How they build kallanai dam

Between 100 and 150 CE, King Karikalan of the Chola Dynasty constructed the initial dam. Situated in the Trichy district, precisely 14 km away from Tiruchirappalli city and 45 km away from Thanjavur city, it is situated on a river. The purpose of building the dam was to redirect the water to the delta regions, enhancing irrigation.[3][4][5] In the 19th century, the British made modifications to this dam. The British assigned Captain Caldwell, a military engineer, in 1804, to investigate the Kaveri River and encourage irrigation in the delta area.[8] He discovered that a significant amount of water flowed onto the Kollidam, leaving a tiny amount behind for irrigation.[8] At first, Caldwell suggested aThe Kallanai was built to redirect the Kaveri River's waters to Kollidam/Coleroon, the river's northern delta branch, via canals across the lush delta region for agriculture. The river Kaveri divides into four streams below the barrage: Kollidam Aru, Kaveri, Vennaru, and Puthu Aru. By activating the barrage/anaicut gates, floodwaters can, nevertheless, be permitted to flow via the other three delta branches and into the sea.[10] It spans the Kaveri and is 329 meters (1,079 feet) long, 20 meters (66 feet) wide, and 5.4 meters (18 feet) high. It is built of unhewn stone.[11] The dam, which is still in great shape, served as a model for other engineers and was used by Sir Arthur Cotton to build his dam across the Kollidam in the 19th century.In 1804, Captain Coldwell rebuilt the Grand Anicut, added dam stones 0.69 meters high to its crest, and enlarged the river embankment above it to guarantee the Cauvery would get more water.
To stop silt from building up in the higher parts of the Cauvery, Major Sim suggested under-sluices in 1829 that would have an outlet into the Coleroon.
British general and irrigation engineer Arthur Cottons made improvements to the dam during the 1800s. It is believed that the Lower Anicut, which Sir Arthur Cotton constructed in the 19th century AD to span Coleroon (Kollidam), the main Cauvery tributary, is a copy of Kallanai.
"Kollidam" refers to a place that has the capacity to hold or accommodate objects. It has a 300,000 capacity.