Water, our most precious resource, is limited and, naturally, unequally distributed. The stress on water resources of India is mounting up as the demand for water is increasing at an alarming speed because of the rapid growth of population, urbanization and industrialization.
In India the average annual water availability has been appraised as 1869 Billion Cubic Metres (BCM) and ground water 433 BCM.
It is the Ministry of water Resources that formulates policies and programmes for the development, regulation and judicious utilization of water.
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Chief Water Resources of India include:
Irrigation as a key component of water resources in India is vital for realizing full potential of agriculture sector of the country. In Areas where rainfall varies very much, the availability of irrigation makes the cultivation of crop more reliable and sustainable.
It is so the significance of the efficient utilization of water resources of India can hardly be ignored. Drought has become an annual phenomenon in India as the delayed arrival of monsoon generally reduces the agricultural returns. Apart from this, the winter crops are more or less dependent on irrigation, hence the need for the irrigation.
Irrigation in India has a history of thousand years, and currently in the field of irrigation India stands first in terms of total irrigated area.
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Canals are one of the oldest and most important water resources of India. However, Canal irrigation is largely limited to the States that form the Great plains of India: Bihar, West Bengal, Uttar Pradesh, Rajasthan, Uttrakhand, Haryana and Punjab) and the states that form the fertile plains of India: Andhra Pradesh, Madhya Pradesh, Karnataka, Odisha and Tamil Nadu.
Some of the important canals of the irrigation system of India are:
The Bari Doab canal; Indira Gandhi canal; Bhakhra canal, Eastern and Western Yamuna canals; the Ganga canal; Agra and Sharda canal; etc. Certain areas of the Thar Desert in the Indira Gandhi Command area, has been transformed by the canal irrigation.
Merits of Canal irrigation
Canals, a cheap and perennial source of irrigation- a very important factor contributing to the water resources of India-,carry a lot of sediment through its water which enrich the fertility of the irrigated fields.
Canals make agriculture sustainable as they help in controlling floods during the rainy season.
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Demerits of Canal irrigation
Overuse and over irrigation, that is certainly misuse, lead to water logging and excessive irrigation causes rise in underground water level.
During rainy season many canals overflow.
Canal irrigation can be practiced very smoothly in the plain areas; in the semi-arid areas canal irrigation cause the problem of usar (Kallar) formation.
Due to overflow of canals water logged areas turn into the breeding grounds for mosquitoes.
Tube-wells and Wells
Tube-wells and Wells form a very important part of water resources in India as they irrigate the largest cropped area of the country. The importance of tube-well irrigation can be gauged from the fact that about 54% of total irrigated areas is under tube-wells and wells irrigation.
Tube-wells irrigation is largely developed in the Northern Plans of India, where about 95% of the tubewells are estabilished and functioning. These areas include Andhra Pradesh, Bihar, Gujarat, Haryana, Karnataka, Madhya Pradesh, Maharashtra, Odissa, Punjab, Uttar Pradesh, and West Bengal.
Merit of Tubewell Irrigation
Tubewells can be installed at convenient places at low cost by the Government and farmers as well. Tubewell as an independent source of income can be installed in a short period of time.
Tubewells can be used when needs arise. Water of tubewells contains several minerals and salt such as nitrate, sulphate, etc. which increase the fertility of soil.
Limitations of Tubewell Irrigation
Mostly during the summer season, underground water table diminishes due to the excessive and non-sensible use of tube-wells.
Through tube-well irrigation only limited areas can be irrigated. When monsoon fails the underground water- table decreases and enough water becomes unavailable for irrigation of crops.
Since electricity and diesel are used in operating tube-wells and pumping sets, tube-well irrigation is considered an expensive method of irrigation.
Tanks have been a major part of water resources of India. Tanks irrigation is largely practiced in the areas where the topography is suitable for acting dams across small rivulets and for the collection of water in artificial lakes such as areas covering the eastern part of the Deccan.
Districts having large number of tanks are: North Arcot, South Arcots, Chengalapattu in Tamil Nadu; Nellore and Warangal districts in Andhra Pradesh. The other states where it is extensive to a lesser extent are Odisha, West Bengal, Karnataka, Uttar Pradesh and Maharashtra.
Potential of Irrigation as the part of water resources in India
It has been claimed that with continuous and systematic development the potential of irrigation has enhanced from 22.6 million hectares in 1951 to 87.8 million hectares in 2010.
Irrigation projects, since April 1978, have been classified classified on the basis of their command area:
Major: involving more than 10,000 hectares
Medium: involving in between 2000-10,000 hectares
Minor: Less than 2000 hectares
Minor irrigation projects, as they cater instant and reliable sources of irrigation to the farmers, are widely distributed. Ground water development, forming major part of the minor irrigation projects, is implemented mainly through the individual and cooperative efforts.
In a recent study of its own the World Bank has disclosed that approximately 20% of the 40 milion hectares of irrigated agricultural land in India suffers from a water logging and salinity problem which have decreased the yield of crops in major quantity.
The kernel strategy for enhancing production of food with sustainable and systematic development of irrigation gains includes extension of irrigation facilities along with consolidation of the existing systems.
It is through major, medium and minor irrigation projects that the irrigation potential has increased from 22.6 million hectares (mha) in 1951 to 103 mha at the end of the tenth plan.
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