Water is the most essential natural resource for life, and its availability determines the pattern of settlement, agriculture and industry. India receives a total annual precipitation of about 4000 cubic kilometres through rainfall and snowfall, which is the main source of the country's water. However, the water resources of India are unevenly distributed in space and time: some regions receive very heavy rainfall, while others such as Rajasthan receive very little, and most of the rainfall occurs in a few months of the monsoon season.
The water resources of India are classified into surface water and groundwater. Surface water includes rivers, lakes, ponds and canals, while groundwater is stored in the aquifers below the ground. The Ganga and the Brahmaputra river systems carry the largest share of India's surface water, while the peninsular rivers such as the Godavari, Krishna and Cauvery flow through the southern plateau. The utilisation of water resources for irrigation, drinking water, industry and power is the basis of India's economy.
The total annual water resources of India are estimated at about 1869 cubic kilometres, of which only a part can be used because of the uneven distribution of rainfall and the difficulty of storing flood waters. The surface water resources are concentrated in the Himalayan rivers and the river systems of the eastern and southern parts of the country. The groundwater resources are found in the aquifers beneath the alluvial plains of the north and the coastal plains, which are recharged by rainfall and percolation.
The water resources of India are unevenly distributed. The rivers of the northern plains, such as the Ganga and the Brahmaputra, carry abundant water, but much of it flows away in floods during the monsoon. The rivers of the Deccan plateau, such as the Krishna and the Cauvery, carry less water and are highly seasonal. The groundwater is plentiful in the alluvial plains of Punjab, Haryana, Uttar Pradesh and West Bengal, but it is scarce in the hard rock regions of the southern peninsula and in the desert regions of Rajasthan.
Water in India is used for several purposes, of which irrigation is by far the most important. About 89 per cent of the total water used in India is consumed by agriculture for irrigation, while domestic use accounts for about 3 per cent and industrial use for about 2 per cent. Irrigation is essential because the rainfall of India is seasonal and uneven, and it is the key to the intensive agriculture of the Punjab, Haryana and western Uttar Pradesh regions.
Irrigation in India is of several types. Wells and tubewells are the largest source of irrigation, especially in the alluvial plains of the north, followed by canals, which are important in the Indo-Gangetic plains and the deltas of the peninsular rivers. Tanks are the traditional source of irrigation in the southern states, especially in Tamil Nadu and Andhra Pradesh. The development of irrigation has increased the area under cultivation, raised crop yields and made the cultivation of water-intensive crops such as rice and sugarcane possible in the dry regions.
Water scarcity is the shortage of water for meeting the needs of a region. India is moving towards a state of water scarcity because the demand for water is increasing rapidly with the growth of population, agriculture and industry, while the availability of water is limited and its quality is deteriorating. The per capita availability of water in India has fallen sharply from about 5177 cubic metres in 1951 to about 1545 cubic metres in recent years.
The causes of water scarcity in India include the over-exploitation of groundwater, the pollution of rivers and lakes, the inefficient use of water in agriculture, the low rate of rainfall in many regions and the loss of water through floods. The falling water table in Punjab, Haryana and western Uttar Pradesh, where groundwater is pumped far faster than it is recharged, is a serious problem. The pollution of the Ganga and the Yamuna and the drying up of many tanks and wells have made water scarce even in areas of adequate rainfall.
The conservation of water is essential for the sustainable development of India. Rainwater harvesting, the collection and storage of rainwater for future use, is the most effective method of conserving water, and it has been revived in many cities and villages. Rooftop rainwater harvesting and the construction of check dams and percolation tanks help recharge the groundwater. The revival of traditional water bodies such as tanks, ponds and wells is also important for water conservation.
The management of water resources in India involves both the increase of supply and the reduction of demand. The construction of multipurpose projects, such as dams for irrigation, power and flood control, has increased the supply of water, but these projects also have environmental and social costs. The efficient use of water through drip and sprinkler irrigation, the pricing of water, the treatment and reuse of wastewater and the protection of rivers from pollution are the key measures for the sustainable management of India's water resources.
Multipurpose projects are dams that serve several purposes at the same time, such as irrigation, hydroelectric power, flood control, drinking water and navigation. Important multipurpose projects of India include the Bhakra-Nangal project on the Sutlej river in Punjab and Himachal Pradesh, the Hirakud project on the Mahanadi in Odisha, the Damodar Valley project in Jharkhand and West Bengal, the Nagarjuna Sagar project on the Krishna river and the Tehri project in Uttarakhand.
The National Water Policy of India, first adopted in 1987 and revised subsequently, provides the framework for the development and management of water resources. It emphasises the priority of drinking water, the need for an integrated approach to the management of surface and groundwater, the participation of users in water management and the conservation of water. The National Water Policy also stresses the need to deal with the interstate sharing of river waters and the growing problem of water pollution and scarcity.
| Use | Share of Total Water Use |
|---|---|
| Irrigation | About 89 per cent |
| Domestic Use | About 3 per cent |
| Industrial Use | About 2 per cent |
| Other Uses | Remaining share |
| Source | Importance |
|---|---|
| Wells and Tubewells | Largest source, mainly in northern alluvial plains |
| Canals | Important in Indo-Gangetic plains and deltas |
| Tanks | Traditional source in southern states |
Water is the most vital resource of India, but its uneven distribution in space and time makes its management a major challenge. The surface water of the Himalayan and peninsular rivers and the groundwater of the northern alluvial plains supply the needs of agriculture, industry and households, with irrigation alone consuming about 89 per cent of the total water used. India is moving towards water scarcity because of rising demand, over-exploitation of groundwater, pollution and inefficiency. The sustainable management of water through rainwater harvesting, efficient irrigation, multipurpose projects and the National Water Policy is essential for the food security and development of the country.
Keywords: Water resources, surface water, groundwater, irrigation, water scarcity, rainwater harvesting, multipurpose projects, National Water Policy.