The increasing needs for water in many parts of the world to meet varied demands especially in arid and semi-arid region has given boost to large inter basin transfers in the last few decades. Accordingly, many schemes of large scale water transfer projects have been planned and some of them implemented and are standing as a land mark for the over all development of the respective regions. A few of them are briefly described here.
Periyar Project: The project is the most notable endeavor of the 19th century in transbasin diversion. The project envisages transfer of water from Periyar basin to Vaigai basin. A masonry gravity dam of 47.28 m high has been constructed across a gorge on west flowing Periyar river. A 1,740 m long tunnel with a discharging capacity of 40.75 cumecs has been driven across the mountain barrier to convey the water eastwards to Vaigai basin. The project was commissioned in 1895 and provided irrigation to 57,923 ha initially, which has since been extended to 81,069 ha. There is also a power station of 140 MW capacity.
Parambikulam Aliyar: The project is a complex multi-basin multi-purpose project of seven streams, five flowing towards the west and two towards the east, have been dammed and their reservoirs interlinked by tunnels. The project envisages transfer of water from Chelakudi basin to Bharatapuzha and Cauvery basins. The water is ultimately delivered to drought prone areas in Coimbatore district of Tamil Nadu and the Chittur area of Kerala states. The command area for irrigation is presently about 1,62,000 ha. There is a total of 185 MW power generation capacity at four power houses. This project was built during the second and third five year plans.
Kurnool Cudappah Canal: A private company started this scheme in 1863. The project envisages transfer of water from Krishna basin to Pennar basin. A 8.23 m high anicut was built on the river Tungabhadra upstream of Kurnool town. A 304 km long canal with a capacity of 84.9 cumecs at its head extends from Krishna to Pennar basin and irrigates 52,746 ha. The scheme was taken over by Govt. of India in 1882.
Telugu Ganga Project: This project has been recently implemented primarily to meet the pressing need of water supply to Chennai metropolitan area. It brings Krishna water from Srisailam reservoir through an open canal, first to Somasila reservoir in Pennar valley. This involves rock cuts upto 35 m deep. From Somasila, the water is taken through a 45 km canal to Kandaleru and then to Poondi reservoir in Tamil Nadu through another 200 km long canal. By mutual agreement, 12 TMC of water will be delivered to Tamil Nadu at the boarder from Krishna basin. This will greatly augment the water supply to Chennai city. The canal also irrigates 2.33 lakh ha. in Andhra Pradesh enroute. The project was made possible by Maharashtra , Karnataka and Andhra Pradesh voluntarily foregoing 5 TMC. each from their entitlement. This project is a fine example not only of hydraulic engineering but also of Inter- State cooperation.
Ravi-Beas-Sutlej- Indira Gandhi Nahar Project: Beas-Sutlej link in combination with the Indira Gandhi Nahar Project is a standing example of how the large inter basin transfers brought about all round socio-economic growth with overall enhancement in the ecology and environment of the region. Under the Indus Water Treaty, the water of three eastern rivers viz. Sutlej, Beas and Ravi were allocated to India. As the land to be benefited in India, lies mostly to the east and south of these rivers, the rivers had to be interlinked and the water conveyed to canal systems for serving vast tracts in India. The main storage on Sutlej is at Bhakra, while that on Beas is at Pong. Bhakra system provides irrigation to 26.3 lakh ha. of new area besides stabilization of existing irrigation of 9 lakh ha. The aggregate generation capacity of power on Bhakra Nangal Project is 1,354 MW. A diversion dam, Pondoh, 140 km upstream of Pong on Beas, enables diversion of water from Beas to Bhakra reservoir and generates 165 MW of power. The Beas-Sutlej link is 37.25 km long of which 25.45 km is tunnel through difficult rock formations. The capacity of the tunnel is 254.70 cumecs. Another dam on Ravi namely, Ranjit Sagar dam will provide additional water to Beas and also generate a large block of power. Subsequently, it was decided to link the Indira Gandhi Nahar Project with the river systems to provide 9.36 BCM of water to Rajasthan Canal for irrigating the areas of Thar Desert.
It is no exaggeration to say that the transfer of surplus waters of Ravi, Beas and Sutlej to Rajasthan right upto Jaisalmer and Barmer through Indira Gandhi Nahar Pariyojana has eliminated drought conditions, provided power benefits, those are writereaddata by the entire North grid, transformed desert waste land into an agriculturally productive area by bringing irrigation and vegetation to about 2 million hectare area. Contribution in agricultural production due to implementation of the project is worth Rs. 1,750 crores annually. Canal water is also available for meeting domestic needs. The Indian military at western boundary receive water from this canal. The project has miraculously changed the living standard and socio-economic conditions of the people in the area.
Inter Basin Water Transfers in Other Countries: Many large-scale water transfer schemes have been planned and implemented in other countries also. In Canada, sixteen inter basin water transfer schemes have been implemented for hydropower development.
In United States, the California's State Water Project, first phase of which was completed in 1973, provides for the diversion of 4 cubic km of flow from better-watered northern California to the drier central and southern parts of the State. The conveyance system comprises of 715 km long California Aqueduct, a complex system of lined and unlined canals, pumping stations, siphons and tunnels. The lift involved is nearly 1,000 m.
The Texas Water Plan envisages redistribution of water in Texas and New Mexico to meet the needs of the year 2020.
Similarly, the waters of the Colorado river (an international river between USA and Mexico) are being supplied outside the basin to the Imperial valley in California.
Major existing and under construction inter basin transfers in Canada include Kemano, Churchill Diversion, Well and Canal, James Bay, Churchill Falls, Bay d' Espoir etc. Proposed inter basin transfers in Canada include Ogoki, Long Lake (for transfer within Canada) and North American Water and Power Alliance (NAWAPA), Grand Canal Concept, Canadian Water, Magnum Plan, Central North American Water Project (CeNAWP), Smith Plan etc. for transfer from Canada to USA.
In Mexico, for the Mexico city water supply, transfer of ground waters from the Lerma basin was completed in 1958. The Water Plan for the North Western Region (PLHINO) conceived a set of inter basin transfers within the Noroeste region.
Mahaveli-Ganga Project of Srilanka includes several inter basin transfer links.
Inter basin transfer projects have also been planned and implemented in China and former USSR. A notable scheme executed in the USSR is Irtysh Karganda scheme in the central Kazakhistan. The link canal is about 450 km long with a maximum capacity of 75 cumec. Lift involved is 14 to 22 m. There is another plan to transfer 90,000 Mcum of water from the north flowing river to the area in south. Other proposals include partial redistribution of water resources of northern rivers and lakes of European part to the Caspian Sea basin involving 2 M. Ha. m of water.
The Lingua Canal was completed in China in 214 BC and the Grand Canal was completed in 605 AD. Recently completed projects in China include Biliuha - Dalian inter basin water supply system, Trans basin transfer of Luhana River to Tiajian and Tengshan, Inter basin diversion of Guanglong province and Inter basin diversions of Fujian province. Diversion of Quiantang river water, diversion of Yellow river surpluses and South to North transfer projects with the West route, Middle route and East route are other proposed projects.