Well and Tube Well irrigation is the most widely used irrigation system in India. The first tube well was dug in 1930 in Uttar Pradesh. There are currently over 50 lakh tube wells in operation across India. It has made a significant contribution to the success of India's Green Revolution. Uttar Pradesh has the most area under well irrigation. It is followed by Rajasthan, Madhya Pradesh, Punjab, Gujarat, Maharashtra, and Bihar. In this article, we will discuss Well and Tube Well Irrigation which will be helpful for UPSC exam preparation.

What is Well and Tube Well Irrigation?

• Tube Well irrigation is the most widely used irrigation system in India.
• There are various types of wells, such as shallow wells, deep wells, tube wells, artesian wells, and so on.
• Water from shallow wells is not always available because the level of water drops during the dry months.
• Deep wells are better for irrigation because their water is available all year.

Wells

• A well is a hole dug in the ground to obtain water from the subsoil.
• A standard well is 3 to 5 metres deep, but deeper wells are 15 metres deep.
• To lift ground water from wells, various methods such as the Persian wheel, Reht, Charas, or mot, dhingly are used.
• Well irrigation accounts for roughly 63% of the country's net irrigated area. Since 1950, well irrigation has increased sixfold.
• Popular areas with enough sweet groundwater are:
  • Northern Plains
  • Deltaic plains of the Mahanadi, Godavari, Krishna, Cauvery, Narmada, and Tapi Valleys
  • Weathered Deccan trap areas
  • Peninsular India's crystalline and sedimentary zone

• Because of the uneven surface, rocky structure, and lack of groundwater, large parts of peninsular India are unsuitable for well irrigation.
• A large dry tract of Rajasthan, adjoining parts of Punjab, Haryana, Gujarat, and some parts of UP have brackish underground water that is unfit for irrigation, human consumption, or irrigation.
• Uttar Pradesh has the most well-irrigated land in the country, accounting for 28% of the total.
• Following Uttar Pradesh are Rajasthan (10%), Punjab (8%), Madhya Pradesh (7.9%), Gujarat (7.3%), and Bihar (6.2%).

Tube Wells

• A tube well is a deeper well (>15 metres) from which water is lifted using a pumping set powered by an electric motor or diesel engine.
• Geographical conditions that favour tube well installation are:
  • Sufficient amount of groundwater (a tube well irrigates 2 hectare per day against 0.2 hectare per day irrigated by ordinary well).
  • Sufficiently high groundwater table to make pumping economical (water table should be 15 metres or higher).
  • Regular supply of cheap electricity and diesel so that water can be extracted as needed.
  • Soil in the immediate vicinity of the tube well should be fertile enough to cover the cost of construction and operation of the tube well through increased farm production.

Types of Wells

Dug Wells

• An indigenous form of irrigation is the use of groundwater through dug well irrigation.
• A dug well is a shallow well with a bottom at or near the water table, allowing water from the surrounding aquifer to accumulate in the well.
• A water lift lifts water collected in the well to the ground surface. When operated with a Persian wheel, the masonry lined dug well typically yields 7 to 8 m3 per hour, which is the case for approximately 20% of the masonry wells.
• Water is lifted by animal power with leather or metal buckets, usually bullocks, in the remaining dug wells.
• These wells have very limited discharge rates, and this practise is nearly obsolete due to the high cost of labour.

Shallow Tube Wells

• Shallow tube wells are typically less than 30 metres deep and are used to penetrate a shallow aquifer.
• This depth is only possible if the tube well is installed at the bottom of a dug well, resulting in a dug-cum-tube well. A small centrifugal pump is usually installed in shallow tube wells.
• The filter point wells of Tamil Nadu's Cauvery deltas in Trichy, Thanjavur, Thiruvarur, and Nagapatinam districts are shallow tube wells that irrigate individual farms.
• A belt drive connects the electric or diesel motor directly to the pump. The centrifugal pump is installed at the surface level and primarily operates in suction mode.

Medium Tube Wells

• Medium tube wells are submersible tube wells with a small diameter and a strainer section.
• These wells are typically 45 metres deep, but they can be deeper depending on the depth of the aquifer and the capacity required. They are powered by centrifugal pumps.
• Water is distributed from these wells via small unlined channels of varying lengths: 30 m for masonry wells, 200 m for shallow tube wells, and 400 m for medium tube wells.

Deep Tube Wells

• Deep tube wells have a large diameter and can reach depths of up to 300 metres.
• Pumps are sunk into the well, run in force mode, and are powered by submersible electric engines or shafts connected to surface engines.
• Deep tube wells have a large discharge capacity. As discharge capacity increases, so does the length of the water distribution channels.
• In state tube well commands of UP, for example, a command area of 100 ha is served by a 4 km water distribution system, with water distributed through unlined earthen channels.

Distribution of Wells and Tube Wells in India

• There were approximately 5 million wells in 1950-51, and the number has now increased to approximately 12 million.
• Well irrigation accounts for more than 60% of the net irrigated area in the country, compared to 29.2% for canal irrigation and 4.6% for tank irrigation.
• It accounted for 59.78 lakh hectares in 1950-51, which increased to approximately 332-77 lakh hectares in 2000-01, resulting in a more than fivefold increase in well irrigation.
• Uttar Pradesh has the most well-irrigated land, with 93-84 lakh hectares, accounting for approximately 28% of India's well-irrigated area.
• Three-fourths of India's total well-irrigated area is in Uttar Pradesh, Rajasthan, Punjab, Madhya Pradesh, Gujarat, Bihar, and Andhra Pradesh.

Distribution of Wells in India

Advantages of Well and Tube Well Irrigation

• The well is the most basic and cost-effective source of irrigation, and even the poorest Indian farmer can afford it.
• A well is an independent source of irrigation that can be used as needed.
• Several chemicals, such as nitrate, chloride, sulphate, and others, are commonly found mixed in well water.
• When they reach the agricultural field, they create soil fertility along with well water.
• It is more reliable during times of famine when surface water is scarce.

Disadvantages of Well and Tube Well Irrigation

• Only a small area can be irrigated with these methods. A well can normally irrigate 1 to 8 hectares of land.
• If too much water is drawn out of the well, it may dry up and become ineffective for irrigation.
• When there is a drought, the groundwater level drops, and there isn't enough water in the well when it's most needed.
• Tube wells can draw a lot of groundwater from nearby areas, leaving the ground dry and unsuitable for agriculture.
• Well and tube well irrigation are not possible in areas with salty groundwater.

Conclusion

Well irrigation is gradually being phased out in favour of energised tube wells. However, many wells continue to be used in areas where electricity is unavailable or farmers cannot afford diesel fuel. It is especially useful in areas with permeable rock structures that allow groundwater to accumulate through percolation. As a result, wells are more common in areas with alluvial soil, regur soil, and so on, and less common in rocky terrain or mountainous regions.