Cauvery

History

It was constructed under the supervision of an Irish engineer, Vincent Hart, who was also the chief engineer of the project. It took nine years and the effort of 17,000 men to complete the dam project. After the construction was complete, Mettur Dam over Kaveri became the largest dam in the world. The funds were provided from the taxes collected in the Madras Presidency. The Board of Revenue was headed by Sir C.P. Ramaswamy Iyer who initiated the building of the dam. As a result, the dam authorities evacuated the people of Nayambadi and some other villages where the dam was sited. When the water level of the reservoir recedes, even now old Christian Church of Nayamabadi and some Hindu temples from other villages emerge from it as proof.

History

The Harangi Hydroelectric Project was set up by Energy Development Company Limited (EDCL) on the Left bank of Harangi Dam, parallel to left bank irrigation canal. The 9 megawatt (2×4.5 MW) project was started in April 1997, and was fully into commercial operation by July 1999. It falls under the "Small" category of hydropower projects (3-25 MW).

The estimated project cost was Rs. 11.06 crores (Rs. 110.6 million) and the actual cost escalated to Rs. 58.00 crores (Rs. 580.0 million). The reservoir covers an area of 20.03 km2 (7.73 sq mi).

Phase-II of the project is to install a 6 megawatt unit, currently under planning.

Geography

The Harangi River originates in the Pushpagiri Hills of the Western Ghats in Kodagu, Karnataka. Heavy rainfall from the south-west monsoon is the source of water in its catchment area which is about 419.58 km2 (162.00 sq mi). The Harangi is the first major tributary of the Kaveri. The length of the Harangi from its origin to the confluence with the Kaveri river is 50 km (31 mi). The Harangi joins the Kaveri near Kudige, 5 km (3.1 mi) north of Kushalnagar.

The Harangi Reservoir, located before the confluence, covers an area of 20.03 km2 (7.73 sq mi). The catchment area is a rich biosphere. Between the open water and the dry land are marshy wetlands.

The area has a highland climate without extreme variations. The rainfall is mostly from the southwest monsoon, during June to September.

Background

Mysore, and Mandya in particular, had always been dry country, and summers regularly pushed people to migrate to wetter areas nearby. A severe drought in 1875–76 killed off a fifth of the population of the Kingdom of Mysore, and crop failures kept recurring for want of irrigation water. The Kaveri was the obvious candidate to change that. An earlier attempt already existed as a model: the Marikanive project, begun in 1897 under Diwan K. Seshadri Iyer and Queen-Regent Kempananjammanni Devi, had shown that the state could fund and build a reservoir of its own.

Construction

Construction began in November 1911. Ten thousand workers were employed.

When the First World War broke out in 1914, it hit the dam's construction in a very specific way. India's own Portland cement industry barely existed at the time: total domestic output in 1914 came to only about 945 tonnes, all of it from a single factory in Madras, so builders across the country still depended almost entirely on cement shipped in from Britain. Wartime shipping shortages made those imports "rapidly dwindle" right as domestic wartime demand for cement, much of it for military use, was climbing. Major civil projects like the Kannambadi reservoir suddenly found themselves cut off from their usual supply of binder, just as work on the dam's main masonry was getting underway.

Operation

Instead of the spillways that most dams use to stop water topping the dam, Visvesvaraya fitted 48 automatic gates, in six sets of eight, that open and close on their own as the reservoir rises and falls. The design wasn't new: he'd invented and patented the same basic mechanism roughly a decade earlier, to solve an almost identical problem at Lake Fife near Khadakvasla in the Bombay Presidency, where the reservoir feeding Poona's water supply and the Mutha Canal kept overflowing every year. His automatic gates there let the lake's storage level rise about eight feet higher without raising the dam itself, adding some 25 per cent more capacity, and opened and closed on their own as the water rose and fell, with no one needing to operate them by hand.

History

The dam was originally built by King Karikalan of the Chola Dynasty in c. 100 – c. 150 CE. It is located on the river in Thanjavur district, exactly 14 km from the city of Tiruchirappalli and 45 km from the city of Thanjavur. The idea behind the construction of the dam was to divert the river to the delta districts thereby boosting irrigation. This dam was re-modeled by the British 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. He found that a large amount of water passed onto the Kollidam leaving behind a small volume for irrigation purposes.

Geography

The Kaveri river splits into two at a point 20 miles (32 km) west of Kallanai. The two rivers form the island of Srirangam before joining at Kallanai. The northern channel is called the Kollidam (Coleroon); the other retains the name Kaveri, and empties into the Bay of Bengal at Poompuhar. On the seaward face of its delta are the seaports of Nagapattinam and Karaikal.

Description

The purpose of the Kallanai was to divert the waters of the Kaveri across the fertile delta 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 and Puthu 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. 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. The dam is still in excellent condition, and supplied a model to later engineers, including Sir Arthur Cotton's 19th-century dam across the Kollidam, the major distributary of the Kaveri.