Water Use Efficiency (WUE) is defined as the ratio between the amount of water actually utilized by a crop and the total amount of water diverted or pumped from a source. In the Indian context, where agriculture consumes nearly 84% of the country’s total available freshwater, improving WUE is a strategic economic necessity. Currently, India’s overall irrigation efficiency is estimated at a low 35% to 40%, significantly trailing global benchmarks of 60% to 70%.
Key Metrics and Indicators of Efficiency
Understanding WUE requires analyzing it at three distinct levels:
- Conveyance Efficiency: The efficiency of water transport from the reservoir to the farm gate through canals or pipes.
- Field Application Efficiency: The ratio of water stored in the root zone to the water delivered to the field.
- Water Productivity: An economic metric expressed as the yield produced per unit of water used (e.g., kg/m³).
Comparative Analysis of Irrigation Methods
The shift from traditional flood irrigation to pressurized systems is the primary driver for improving WUE in the Indian economy.
| Irrigation Method | Field Application Efficiency | Primary Losses |
| Surface/Flood Irrigation | 30% – 45% | Evaporation, Deep Percolation, Runoff |
| Sprinkler Irrigation | 75% – 80% | Wind drift, Evaporation during spray |
| Drip Irrigation | 85% – 95% | Minimal (Targeted at root zone) |
Structural and Economic Barriers to High WUE
- The “Rice-Sugar” Paradox: Though India is water-stressed, a significant portion of irrigated land is dedicated to water-intensive crops like sugarcane and paddy, which have low water productivity but high MSP (Minimum Support Price) security.
- Subsidized Power: Low or zero electricity tariffs for farmers lead to the “tragedy of the commons,” where groundwater is pumped indiscriminately regardless of actual crop requirement.
- Canal Siltation and Seepage: Unlined and poorly maintained canal systems result in massive transit losses before water reaches the tail-end farmers.
Strategic Initiatives to Enhance WUE
Pradhan Mantri Krishi Sinchayee Yojana (PMKSY) – “Per Drop More Crop”
The PDMC component focuses specifically on Micro-Irrigation (MI).
- Objective: To increase the area under drip and sprinkler systems through financial assistance (subsidies) to farmers.
- Incentives: Small and marginal farmers receive up to 55% subsidy, while others receive 45%.
Bureau of Water Use Efficiency (BWUE)
Established under the Ministry of Jal Shakti, this dedicated body aims to:
- Promote, regulate, and monitor WUE in the domestic, industrial, and agricultural sectors.
- Set standards and labels for water-efficient appliances and irrigation equipment, similar to BEE star ratings for electricity.
National Water Mission (NWM)
One of the eight missions under the National Action Plan on Climate Change (NAPCC), its “Goal 4” specifically targets increasing water use efficiency by 20% across all sectors through incentive-based mechanisms.
Technical Interventions for Improving Efficiency
- Fertigation: The process of applying fertilizers through a drip irrigation system, which improves nutrient uptake and reduces fertilizer leaching into groundwater.
- Laser Land Leveling: Ensuring a perfectly flat field surface to prevent water from pooling in low spots or running off high spots, saving up to 20% of water.
- Soil Moisture Sensors and IoT: Real-time monitoring allows for “Precision Irrigation,” where water is applied only when the soil moisture drops below a specific threshold.
- Mulching: Covering the soil with organic matter or plastic films to reduce evaporation losses and maintain root zone moisture.
Institutional and Community Frameworks
- Participatory Irrigation Management (PIM): Transferring the management of irrigation systems to Water User Associations (WUAs). When farmers “own” the water, they are more likely to manage it efficiently.
- Warabandi System: A rotational water allocation method used in canal commands to ensure equitable and timed distribution, reducing wastage by over-irrigation at the “head.”
- Virtual Water Trade: Economists suggest that India should import water-intensive crops and export water-efficient ones to balance its “virtual water” budget.
Factful Trivia for UPSC Prelims
- Israel Model: India has a strategic partnership with Israel to implement advanced WUE technologies in semi-arid regions like Bundelkhand.
- Highest Water Productivity: Millets and oilseeds have significantly higher water productivity compared to rice and sugarcane.
- Blue Water vs. Green Water: “Blue water” refers to surface and groundwater, while “Green water” is the rainwater stored in the soil as moisture. Improving WUE focuses primarily on Blue water management.
- Micro-irrigation Fund (MIF): A ₹5,000 crore fund created with NABARD to facilitate states in mobilizing resources for expanding micro-irrigation.
- Pattiseema Project: It is an example of an interlinking project designed to save water by diverting “surplus” flows to “deficit” basins, thereby improving basin-level WUE.