The irrigation sector uses the highest amount of water in India amongst all other sectors. It is also one of the most adversely affected sectors because of its high dependence on erratic rainfall and shrinking water reservoirs. The target of delivering high productivity in agricultural produce further adds pressure on these limited water resources. Many of the irrigation projects in India are very old and report low efficiency. As a result, the sector has realigned its goals to achieve water use efficiency (WUE) through many regulatory and implementation strategies. Irrigation being a subject matter under the state list of the Seventh Schedule of the Constitution of India, the responsibility of implementing innovations in this sector lies with state governments. The central government supports the efforts of state governments in creating frameworks for specific policies and guidelines for WUE in their irrigation projects.
Policy and guidelines-based measures
WUE is considered crucial for efficient water usage and distribution for irrigation compared to its withdrawal. The government has taken steps to ensure that irrigation projects meet definite benchmarks of WUE by formulating policies, guidelines and programmes. To this end, the National Water Policy formulated in 2012 has emphasised the importance of WUE and has suggested measures such as avoiding water wastage with the use of economic incentives and penalties and the creation of independent statutory water regulatory authorities in each state, among others. It has also recommended that water charges be decided on a volumetric basis and industries recharge water resources by returning their treated effluents up to a specified standard. Similarly, one of the five goals of the National Water Mission established by the Government of India is to increase WUE by 20 per cent. The Bureau of Water Use Efficiency (BWUE) was set up under the Ministry of Jal Shakti in October 2022 to achieve this target in various sectors including irrigation. A dedicated task force has been set up for the preparation of an execution framework for implementation. It submitted a related report to the BWUE in August 2023. Subsequent additional sections were submitted by it in October 2023.
Further, to anchor this domain, the Central Water Commission (CWC) has set out guidelines to improve the WUE in various sectors, including the irrigation sector. Along with the Central Ground Water Board, it has formulated the “General Guidelines for Water Audit and Water Conservation”. These broad guidelines instigate state governments to undertake water audits under their irrigation projects by creating specific guidelines. Moreover, state irrigation policies must also align with the National Water Policy and state irrigation acts to underpin the high standard of WUE in irrigation practices. Further, the Water and Land Management Institutes (WALMIs), which are state-level training institutes, must be strengthened to impart multi disciplinary training in the field of irrigated agriculture. These WALMIs must facilitate the training of the staff and personnel.
In a similar move, under the Pradhan Mantri Krishi Sinchayee Yojana, the component of Command Area Development and Water Management also aims at improving agricultural productivity and WUE. Moreover, it aims to enhance WUE to 90 per cent at the farm level, with a strong infrastructure to provide surface water. This can be facilitated by shifting from the existing command (gravity-based or rain-fed) to a pressurised piped irrigation command.
New irrigation methods, strategies and technologies
The improvement of WUE is dependent on the efficiency of irrigation methods deployed. Old methods are being upgraded to new and evolved systems that avoid water wastage, allow proper nutrient absorption and facilitate the expansion of agricultural coverage. In this regard, precision irrigation is one of the methods that ensures increased yields and fertility, soil protection and preserves scarce water resources. Under this method, the moisture is delivered through tiny pipes placed in lines, called drip tape or drip line watering. The water droplets are supplied directly to the roots of crops at low pressure. This system has the major advantage of blocking the growth of weeds with a limited and regulated water supply, which in a usual case scenario leads to plant starvation. However, these drip tapes can be easily blocked with impermeable objects and, therefore, soluble materials can help in combining water supply and fertilisation.
A few advancements are taking place in precision irrigation with technology integration. These include precision mobile drip irrigation; precision irrigation management using EOS data analytics crop monitoring, normalised difference moisture index, soil moisture data and weather forecast; farmer-friendly mobile app-based operations; drone-based water stress monitoring; and precision irrigation using the FAO CROPWAT model.
Furthermore, management information systems and decision support systems are being used to respond to changes in the water flow of a canal system promptly. It allows precise measurements of water flow and better communication facilities, which helps in swift action. Similarly, water savings are considerably being controlled with the practice of micro-irrigation systems. Under this, micro-sprinkler and drip irrigation systems are adopted in water-scarce areas. Auto irrigation systems are also integrated with this system that can sense the water stress in the soil through tensiometers. These meters are installed at suitable depths and locations and their output is converted into an electrical signal with the help of a transducer.
Project examples and underlying gap
While the government is taking measures to enhance the quality and efficiency of irrigation in the projects pan-India, their progress remains slow. WUE studies were conducted by the CWC on 35 irrigation projects in Andhra Pradesh, Haryana, Uttar Pradesh, Bihar and Punjab. These projects have different cultivable command area (CCA), which is the area that can be irrigated from a scheme and fit for cultivation. The CCA ranges from 2,600 hectares (ha) to 889,000 ha for these 35 selected projects. The overall average WUE across these projects was reported to be around 36 per cent. Along with this, the conveyance efficiency was 69 per cent, while the on-farm application efficiency was 55 per cent. These components define the efficiency of the water reaching the field as against conveyed from the source and the farm output compared to the input water. Of these projects, only nine projects reported having more than 50 per cent WUE, with the highest WUE reported as 62 per cent, at the Koil Sagar project in Andhra Pradesh (11,700 ha CCA), followed by 58 per cent at the Bhairavanithippa project in Andhra Pradesh (4,856 ha CCA) and 57 per cent at the Augmentation Canal project in Haryana (85,443 ha CCA). The lowest WUE was 13 per cent, at the Nagal Lift project in Haryana (35,721 ha CCA).
The Koil Sagar project, is a medium-sized irrigation project located in Deverakadra Mandal of Mahabubnagar district in Andhra Pradesh. It was constructed at a cost of Rs 800 million. The project was planned and built to meet the irrigation needs of about 12,000 acres. The capacity of the reservoir is 2.276 thousand million cubic feet. Despite high WUE, only around 5,000 acres is irrigated on an average under the project because of low rainfall and insufficient inflows to the reservoir. Meanwhile, the Bhairavanithippa project was built across the Pedda Hagari river at Bhairavanithippa in Gummagatta, Andhra Pradesh. It had an estimated cost of Rs 14.38 million and was designed to irrigate 12,000 acres of land through two canals located on either side of the reservoir.
In sum
As the sector realigns its attention to optimise and strategise its water usage, some upcoming action plans would also support the sector. For instance, in January 2024, the Ministry of Jal Shakti urged all the states to prepare a road map for WUE for the next 10-15 years. Some of its targets include groundwater regulation, which will also affect the current irrigation practices relying majorly on groundwater. Further, the interlinking of river-based projects will also improve water distribution for irrigation in water-scarce areas. Similarly, a draft action plan based on the findings and recommendations of the task force under the BWUE has been prepared for the next two years. This will help in regulating the use of water in irrigation effectively.
Shubhangi Goswami
