BACKGROUNDER   

The rainfall over the country is primarily orographic, associated with tropical depressions originating in the Arabian Sea and the Bay of Bengal.  The summer monsoon accounts for more than 85 per cent of the precipitation.  The uncertainty of occurrence of rainfall marked by prolonged dry spells and fluctuations in seasonal and annual rainfall is a serious problem for the country.  Large parts of Haryana, Maharashtra, Andhra Pradesh, Rajasthan, Gujarat, Madhya Pradesh, Karnataka and Tamil Nadu are not only in deficit in rainfall but also subject to large variations, resulting in frequent droughts and causing immense hardship to the population and enormous loss to the nation.  The water availability even for drinking purposes becomes critical, particularly in the summer months as the rivers dry up and the ground water recedes.  Regional variations in the rainfall lead to situations when some parts of the country do not have enough water even for raising a single crop.  On the other hand excess rainfall occurring in some parts of the country create havoc due to floods.

 Irrigation using river water and ground water has been the prime factor for raising the food grain production in our country from a mere 50 million tonnes in the 1950s to more than 200 million tonnes at present, leading us to attain self sufficiency in food.  Irrigated area has increased from 22 million hectares to 95 million hectares during this period.  The population of India, which is around 1000 million at present, is expected to increase to 1500 to 1800 million in the year 2050 and that would require about 450 million tonnes of food grains.  For meeting this requirement, it would be necessary to increase irrigation potential to 160 million hectares for all crops by 2050.  India's maximum irrigation potential that could be created through conventional sources has been assessed to be about 140 million hectares.  For attaining a potential of 160 million hectares, other strategies shall have to be evolved.

Floods are a recurring feature, particularly in Brahmaputra and Ganga rivers, in which almost 60 per cent of the river flows of our country occur.  Flood damages, which were Rs. 52 crores in 1953, have gone up to Rs. 5,846 crores in 1998 with annual average being Rs. 1,343 crores affecting the States of Assam, Bihar, West Bengal and Uttar Pradesh alongwith untold human sufferings.  On the other hand, large areas in the States of Rajasthan, Gujarat, Andhra Pradesh, Karnataka and Tamil Nadu face recurring droughts.  As much as 85 percentage of drought prone area falls in these States. 

One of the most effective ways to increase the irrigation potential for increasing the food grain production, mitigate floods and droughts and reduce regional imbalance in the availability of water is the Inter Basin Water Transfer (IBWT) from the surplus rivers to deficit areas.  Brahmaputra and Ganga particularly their northern tributaries, Mahanadi, Godavari and West Flowing Rivers originating from the Western Ghats are found to be surplus in water resources.  If we can build storage reservoirs on these rivers and connect them to other parts of the country, regional imbalances could be reduced significantly and lot of benefits by way of additional irrigation, domestic and industrial water supply, hydropower generation, navigational facilities etc. would accrue.

Earlier Proposals

Suggestions for a National Water Grid for transferring surplus water available in some regions to water deficit areas have been made from time to time.  The two such proposals put forth earlier in the seventies, which attracted considerable attention, were:

Dr. K.L. Rao’s  Proposal (1972), which had  2640 km. long  Ganga - Cauvery link as its main component involved large scale pumping over a head of 550 m. The power requirement for lifting the water was huge, estimated to be 5000 to 7000 MW, for irrigating an additional area of 4 million hectares only. The scheme was also not having any flood control benefit.  Dr. Rao had estimated this proposal to cost about Rs. 12,500 crores, which at 2002 price level comes to about Rs. 1,50,000 crores.  The Central Water Commission, which examined the proposal, found it to be grossly under estimated and economically prohibitive.  

Capt. Dastur Proposal (1977) envisaged construction of two canals – the first 4200 km. Himalayan Canal at the foot of Himalayan slopes running from the Ravi in the West to the Brahmaputra and beyond in the east; and the second 9300 km Garland Canal covering the central and southern parts, with both the canals integrated with numerous lakes and interconnected with pipelines at two points, Delhi and Patna.  The cost estimated by Capt. Dastur was Rs. 24,095 crores.  The proposal was examined by two committees of experts comprising Senior Engineers from CWC, State Governments, Professors from the IIT, Delhi and Roorkee University and Scientists from Geological Survey of India and Indian Meteorological Department who opined that the proposal was technically infeasible.  The cost estimated by the experts in 1979 was about Rs. 12 million crores. The realistic cost at 2002 price level comes to about Rs. 70 million crores.

Existing Experience

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 19^th 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 write read data 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.

SK/BS