Irrigation

1. Irrigation and the agrarian economy

Indian agriculture depends heavily on the southwest monsoon, whose rainfall varies across regions and years. Irrigation reduces exposure to dry spells and allows cultivation during the rabi and summer seasons. Assured water encourages investment in improved seeds, fertilisers, machinery and high-value crops. It helped sustain the Green Revolution in northwestern India and supports intensive rice cultivation in several river deltas.

Irrigation can increase both yield per hectare and cropping intensity, which is gross cropped area divided by net sown area, multiplied by 100. Protective irrigation supplies limited water at critical growth stages to prevent crop failure. Intensive irrigation seeks higher output through more assured supplies. Its benefits depend on timing, reliability, drainage and soil conditions, not merely the volume delivered.

Distribution matters as much as aggregate coverage. Canal head-reach farmers may receive excessive water while tail-end farmers face shortages. Smallholders may lack money for borewells or pumps and depend on water purchases. Rainfed regions therefore need watershed treatment, soil-moisture conservation and supplementary irrigation alongside investment in larger infrastructure.

• Irrigation potential created: area expected to be irrigated by completed infrastructure.
• Irrigation potential utilised: the portion of that potential actually brought under irrigation.
• A utilisation gap can arise from incomplete field channels, unreliable supply, poor maintenance, inadequate drainage or weak coordination.

2. Sources, methods and project classification

Surface irrigation sources include rivers, reservoirs, canals and tanks. Perennial canals draw regulated or dependable supplies, whereas inundation canals depend on high river levels. Tanks store runoff and are particularly important in parts of peninsular India. Besides irrigation, functioning tanks can support groundwater recharge, fisheries and local ecosystems. Siltation, encroachment and disruption of feeder channels reduce their usefulness.

Groundwater irrigation through dug wells and tube wells offers farmers greater control over timing than many canal systems. Alluvial aquifers of the Indo-Gangetic plains generally store more groundwater than the fractured hard-rock aquifers widespread in peninsular India. However, local availability depends on recharge, geology and extraction. Lift irrigation raises water using pumps; gravity irrigation conveys it along a suitable slope.

Application methods are a separate classification. Surface methods include basin, border and furrow irrigation. Sprinklers distribute pressurised water through nozzles and suit many uneven or sandy fields, though wind and evaporation can reduce performance. Drip systems deliver frequent, small quantities near the root zone. Their emitters require filtration and maintenance, and their suitability depends on crops, spacing and water quality.

• Major irrigation project: culturable command area exceeding 10,000 hectares.
• Medium irrigation project: culturable command area exceeding 2,000 hectares and up to 10,000 hectares.
• Minor irrigation project: culturable command area up to 2,000 hectares; it can use either surface water or groundwater.

3. Water productivity and environmental risks

Conveyance efficiency concerns water delivered from the source to the field; application efficiency concerns water stored usefully in the crop root zone relative to water applied. Water productivity measures output or economic value per unit of water. Canal lining, land levelling, irrigation scheduling, mulching and micro-irrigation can improve performance, but their results are location-specific.

Drip irrigation can reduce soil evaporation, unwanted weed growth and nutrient losses. Fertigation applies soluble fertilisers through irrigation water, allowing more precise delivery. Constraints include initial cost, clogged emitters, maintenance requirements, fragmented holdings and weak after-sales service. Sprinklers are not equally suitable for every crop or climate, and micro-irrigation does not eliminate the need for appropriate scheduling.

Excessive irrigation without drainage can raise the water table and cause waterlogging. Evaporation may concentrate salts near the soil surface, reducing crop growth. Salinity is associated with excess soluble salts, while sodicity involves excessive exchangeable sodium and often poor soil structure. Leaching requires suitable water and drainage; gypsum is commonly used to reclaim sodic soils, not as a universal remedy for all salt-affected land.

Water saved at field level is not necessarily saved at basin level. Some canal seepage and field percolation recharge aquifers or become downstream return flows. Moreover, farmers may use efficiency gains to expand irrigated area or cultivate thirstier crops. This rebound effect makes extraction limits, crop planning and groundwater monitoring important complements to improved equipment.

4. Institutions, schemes and policy instruments

Water is primarily a State List subject under Entry 17, subject to Union powers concerning inter-State rivers and river valleys under Union List Entry 56. States manage most irrigation systems, while the Union supports financing, technical standards and inter-State coordination. Groundwater management is complicated by dispersed users and the practical connection between land access and well ownership.

Pradhan Mantri Krishi Sinchayee Yojana, launched in 2015, promotes irrigation access and efficient water use through the ideas of Har Khet Ko Pani and More Crop Per Drop. The Accelerated Irrigation Benefits Programme supports completion of eligible major and medium projects. Command Area Development and Water Management addresses field-level distribution and the gap between potential creation and utilisation. Watershed development supports rainfed landscapes through runoff management, soil conservation and water harvesting.

Per Drop More Crop operated as a PMKSY component from 2015–16 and has been implemented under Rashtriya Krishi Vikas Yojana from 2022–23. It promotes micro-irrigation. NABARD’s Micro Irrigation Fund supports states in expanding coverage. Atal Bhujal Yojana was designed for community-led groundwater management in water-stressed areas of seven states, using water-security planning and demand-side measures.

Participatory Irrigation Management involves Water Users’ Associations in allocation, maintenance and fee collection. Rational water charges can support maintenance, while reliable electricity and carefully designed pump incentives can discourage waste. Solar pumps under PM-KUSUM reduce dependence on diesel, but cheap pumping can increase groundwater extraction unless accompanied by safeguards or incentives to sell surplus electricity.

5. Regional priorities and an integrated approach

Northwestern India needs groundwater demand management and viable alternatives to water-intensive paddy in stressed locations. Parts of eastern India have scope for improved irrigation access, but flooding, drainage, energy access and local aquifer conditions must guide investment. Hard-rock regions of the Deccan need careful groundwater budgeting because storage is limited and borewell yields can be highly variable.

A sustainable approach combines maintenance of existing infrastructure, tank restoration, conjunctive use of surface water and groundwater, and crop choices suited to local agro-climatic conditions. Conjunctive use can reduce pressure on individual sources and help manage waterlogging. Procurement policies, agricultural extension and markets must support diversification; simply advising farmers to change crops is insufficient when income risks remain high.

For examination purposes, avoid treating large dams, groundwater recharge or drip irrigation as universal solutions. Irrigation policy must balance agricultural production with drinking-water needs, environmental flows, equitable access and long-term aquifer health.

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