India got her independence in 1947. Since then, dams in India have been built across many perennial rivers. These dams are a part of the several multi-purpose projects launched by India to serve a variety of needs. In a multi-purpose project, a river forms a unit and a river valley is developed, by exploiting all the resources of the river.

Dams are built to harness the river water so that it can be utilised according to needs. A multipurpose project is launched often for storing water for irrigation purposes, generating hydro-electricity by utilising the water stored by the dams, preventing floods and facilitating afforestation in the catchment areas of the reservoirs. However, the dams also provide drinking water, using the canals for navigation in some areas and also facilitating pisciculture and recreational activities. The main multipurpose projects constituting the major Indian dams are the Hirakud Project in Orissa, the Bhakra Nangal in Punjab, the Damodar Valley Project in Bihar and Bengal, the Tungabhadra Project in Andhra Pradesh and Karnataka, the Rihand Project in Uttar Pradesh.

At independence, in 1947, there were fewer than 300 large dams in India and by the year 2000 the number had grown to over 4000, more than half of them built between 1971 and 1989. India is declared to be the third in the world in dam building, after US and China. While some of the Indian dams were built primarily for flood control, water supply, and hydroelectric power generation, the primary purpose of most Indian dams (96 percent) remains irrigation. In fact, large dam construction in India has been the main form of investment in irrigation undertaken by the Indian government. But, starting in the 1980s, public investment in large dams in India has been the subject of a sustained controversy that was epitomized by the Sardar Sarovar Project, based on the balance between the social, environmental, and economic costs of dams and their benefits.

Most irrigation dams in India are embankment dams, meaning that they consist of a wall built across a river valley to impound water so as to form a reservoir upstream and a system of spillways and gates to bypass the wall so as to maintain normal river flow and convey water to a network of canals feeding irrigated regions downstream. The upstream areas that feed the dam and those submerged by its reservoir are called its "catchment" area, and the downstream areas fed by its irrigation canals and are known as the "command" area. The proponents of large dams focus on the aggregate productivity benefits, emphasizing the role of dams in enabling irrigation.

Owing to the construction of dams in India, between 1951 and 2000, India`s production of food grains increased fourfold, from 51 million tonnes to about 200 million tonnes. This not only obviated the importation of food grains, with attendant saving in foreign exchange, but left India with a marginal food grain surplus. The most optimistic estimates of these dams attribute 25 percent of the increase in food grain production to dam irrigated areas. But it is incorrect to attribute the entire production gains in dam-irrigated areas to dams. However, there are also certain disadvantages of dams in India. Large-scale impounding of water increases exposure to vector-borne diseases, such as malaria, schistosomiasis, filariasis, and river blindness. Although dams may also increase economic activity in the catchment area, such as tourism and fishing, these increase are either temporary or depend on the ability to learn new trades.

One specific determinant of dam construction in India, however, is geographic suitability. Dam location is strongly influenced by river gradient. A river flowing at a moderately positive gradient favors irrigation dams; higher water levels upstream facilitate water storage and diversion into irrigation canals. Consequently, within states, new dams tend to be built in those regions that have river flowing at a moderate incline. After one accounts for the impact of the overall higher altitude of the district and the availability of rivers, the gradient of the rivers is unlikely to have a direct impact on changes in agricultural productivity or other district-level outcomes before and after a state builds new dams. Therefore, it is advised to use the variation in dam construction induced by differences in river gradient across districts within Indian states to determine the impact of large dams.

Large dam construction has been an important and expensive undertaking for the Indian government. While dams have enhanced agricultural productivity in India, there is no evidence that they have been very cost effective, and they have significantly adverse distributional implications. The case of large dams recommends strongly that distributional implications of public polices should be integral to any decision. Punjab, Haryana and Rajasthan have jointly launched the Bhakra-Nangal Project. It is the biggest multi-purpose project in India, started in1948 and completed in 1968. This project derives its name from the two dams Bhakra and Sutlej, built on a tributary of the Indus, the Sutlej. The Hirakud Dam Project is the first major multipurpose river valley project in India, after India was liberated from the British rule in 1947. Constructed across the river Mahanadi at about 15 Kms. upstream of Sambalpur town in Orissa the main dam, the Hirakud is 6 Kms from NH(National Highway) 6 and 8 kms from the Hirakud railway station.

The Rihand project is the most important multi-purpose project in Uttar Pradesh. The Rihand River flows across a narrow gorge in the Vindhyan ranges in the Mirzapur district of Uttar Pradesh. It may appear lazy and docile in the dry season but during the monsoons it is a very strong and vicious river. The Tungabhadra project is a joint venture of the states of Karnataka and Andhra Pradesh. The Tungabhadra dam , 2441 metres in length and 49.38 metres in height, is constructed on the Tungabhadra river at Mullapuram(in Bellary district) about 4.8 kilometres from Hospet. The Damodar Valley Corporation (DVC) handles the Damodar Valley Project. Launched on the river Damodar, this project benefits the states of West Bengal and Bihar. An important feature of this project is the 692 metres long and 11.6 metres high barrage constructed across the Damodar at Durgapur. The Right Bank canal and the Left Bank canal, originating from the barrage are used for irrigation and navigation respectively.

The dams of India have developed the internal navigation by which the pressure on the railways has relieved to some extent. Moreover, these dams have effectively controlled floods on rivers, thus preventing untold damage to the people of the nation.

DAM / Project	RIVER	States benefited
Bhakra-Nangal Project	River Sutlej	Punjab, Haryana and Rajasthan
Hirakud Dam Project	River Mahanadi	Orissa
Rihand Project	River Rihand	Uttar Pradesh
Tungabhadra Project	River Tungabhadra	Karnataka and Andhra Pradesh
Damodar Valley Project	River Damodar	West Bengal and Bihar