A well is a small hole dug in the earth surface from which subsoil water is taken out for irrigation and drinking purposes. It is a cheap, dependable and popular source of irrigation in the country. About 33.28 million hectares of net cropped area (60.8% of the net irrigated area) is irrigated by wells . Well irrigation is practised in areas where plenty of ground-water is available and the depth of water-table does not exceed 15 m.
The largest concentration of wells is found in the Ganga Plain area from Punjab to Bihar. Besides wells are widely scattered in eastern Rajasthan, Gujarat, Maharashtra, Madhya Pradesh, Andhra Pradesh, Karnataka and Tamil Nadu. In Gujarat wells contribute 78.8 per cent of the net irrigated area of the state. Uttar Pradesh, Rajasthan, Maharashtra, Punjab and Madhya Pradesh are other states where more than 50 per cent of the net irrigated area of the state is irrigated by wells (including tube wells).
Water from the wells are lifted by four methods-(a) lever method which is very common in Bihar and Andhra Pradesh, (b) inclined plane method, normally run by a pair of bullocks is mostly used in Uttar Pradesh, (c) Persian wheel method mainly used in Punjab and western Rajasthan, and (d) power driven pumps (tube wells) lifting water from the depths beyond 15 m.
Tube wells are presently most popular source of irrigation in India. Their use started in 1930 and with the launching of five year plan their digging started in the Ganga plain under minor irrigation programmes.
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Today there are more than 45 lakh tube weils under government and private ownership. Private tube wells (also called pumping sets) are very useful, convenient and dependable source of irrigation for individual farmers.
Their cost of digging is within the reach of average farmers. Uttar Pradesh has the largest number of tube wells in the country. Here these tube wells have been bored both on the north and south of the Ghaghara River.
Tube well irrigation is very popular in the districts of Bahraich. Gonda, Basti, Gorakhpur, Deoria, Faizabad, Sultanpur, Azamgarh, Ghazipur, Ballia, Jaunpur, Varanasi districts. In Punjab and Haryana these have been dug in Ludhiana, Kapurthala, Patiala, Hisar and Gurgaon districts. In these districts the depth of tube wells varies between 90 to 150 meters. In the western Rajasthan tube well irrigation is practised in the Luni Basin. Some tube wells also exist in Gujarat (Vadodara and Ahmadabad districts. In Bihar tube wells are found both on the north and south of the Ganga River. In Madhya Pradesh they are primarily located in the Narmada valley.
Well irrigation occupied 59.78 lakh hectares of net irrigated area in 1950-51 which increased to 332.77 lakh hectares in 2000-01, showing an increase of 457% during the last 50 years.
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The spectacular gain is mainly attributed to the popularity of tube-wells (pumping sets) amongst the rich and medium farmers. Well irrigation has contributed substantially for the success of Green Revolution in the country. Like its counterpart tank irrigation, it also suffers from certain drawbacks. It depends on underground water resources whose distribution is not uniform throughout the country. It is difficult to dig wells or bore tube wells in the hilly region of the north and stony area of the Peninsula.
The traditional wells deriving water from first stratum of the ground water are drying up due to the over withdrawal of the ground water and lowering of the water table. The excessive and unplanned use of ground water is going to create a serious water crisis in coming days. In some areas of Rajasthan the ground water is saline and is at great depth. Availability of electricity and diesel regularly and cheaply to the farmers to operate tube wells is still a distant dream. Excessive irrigation in some areas is also a matter of concern.