Latest estimates based on FAOSTAT data indicate that around 22.5 percent of the world’s cultivated land is currently irrigated, accounting for approximately 48 percent of global crop production (see Chapter 2). As irrigation plays an increasing role in agricultural production, better use of water in agriculture becomes increasingly important.
Improving irrigation water productivity
There is considerable scope for improving water productivity in agricultural systems around the world. Many farmers in developing countries could increase water productivity by adopting proven agronomic and water management practices; this is because raising land productivity generally leads to increases in water productivity. Promising pathways for raising water productivity are available along the continuum from fully rainfed to fully irrigated farming systems. These include supplemental irrigation (irrigation supplements rainfall); soil fertility maintenance; deficit irrigation (the crop is irrigated with water below the full requirement for optimal plant growth, to increase crop water productivity); small-scale practices for water storage, delivery and application; pressurized irrigation technologies (e.g. sprinkler and drip irrigation); and soil and water conservation through zero or minimum tillage. The choice of the most appropriate technologies depends on a range of factors, including climatic conditions, sources and cost of energy, labour availability, depth of groundwater sources, and infrastructure costs.
Reducing evaporation from the soil while increasing productive transpiration by plants can also enhance water productivity. Evaporation can account for a very high share of evapotranspiration in rainfed systems with low plant densities. Perhaps surprisingly, drip and sprinkler irrigation systems do not necessarily result in less evaporation than good surface irrigation systems (Burt, Howes and Mutziger, 2001). Practices to shade the ground (e.g. mulching, ploughing or plant breeding for fast leaf expansion) reduce evaporation and increase productive transpiration.
Increasing economic water productivity (more value per unit of water) can be done by switching to higher-value agricultural products or by reducing production costs. Integrated approaches such as agriculture–aquaculture systems, better integration of livestock in irrigated and rainfed systems, and use of irrigation water for household and small industries, can all make a significant contribution to increasing the value per drop. For example, better veterinary services can improve water productivity because healthier animals provide more benefits per unit of water.
Modernization of irrigation schemes
Irrigation infrastructures developed during the twentieth century increasingly require technical and managerial upgrades to ensure that they respond to the need for productive and sustainable agriculture. Increasing competition for resources requires the adoption of multicriteria analysis to prioritize irrigation schemes for modernization,h integrating digital and modern techniques, strengthening water governance and policy frameworks, integrating environmental considerations and ecosystem-based solutions, and promoting data-driven irrigation practices. Both farmers and policymakers are frequently keen to introduce modernization. However, irrigation modernization is financially resource-intensive and requires a careful prioritization process.
In Spain, over a period of two decades, around 20 percent of the country’s irrigation units were modernized. Modernization efforts were found to improve water management capacities, enhance crop yields and reduce energy costs, but the abandonment of marginal and structurally deficient irrigated areas remains a concern for the local population. A critical challenge was that public co-funding and policy-driven efforts were insufficient to address the needs of all irrigated areas, and a significant proportion of irrigation units remain reliant on obsolete irrigation infrastructure (Playán et al., 2024).
A systematic approach to prioritizing irrigation systems for modernization should be based on multiple criteria. The Prioritization of Irrigation Schemes for Modernization/Rehabilitation (PRISM) tool developed by FAO (Pek, 2022) evaluates various critical factors to help decision-makers allocate resources effectively. These include water availability and water-use efficiency, system performance, potential productivity gains, environmental sustainability and socioeconomic benefits. By considering these criteria, PRISM helps to identify irrigation systems where modernization investments can yield the most substantial benefits. One of the core strengths of this tool is its ability to guide data-driven decision-making, ensuring that irrigation modernization is based on robust, evidence-based assessments (see Box 7). The tool integrates both technical and socioeconomic factors, providing a balanced evaluation of each system. Its flexibility enables it to be adapted to specific local and national conditions, enhancing its usefulness across various regions. By promoting irrigation system upgrades in locations that have the greatest potential for efficiency and productivity improvements, PRISM aligns modernization efforts with global goals for sustainable food production.
Box 7Prioritization of Irrigation Schemes for Modernization/Rehabilitation in Tajikistan
In Tajikistan, the Prioritization of Irrigation Schemes for Modernization/Rehabilitation (PRISM) tool has been applied to guide the prioritization of irrigation systems requiring modernization in the Zarafshon Basin (Pek, 2022). The country’s reliance on irrigation for agricultural production, coupled with an ageing infrastructure and water scarcity issues, made it a prime candidate for the application of PRISM. The tool has helped to identify high-priority systems where investments could yield the most substantial benefits in terms of productivity gains and water resources management.
Its use in Tajikistan demonstrates the tool’s effectiveness in guiding national-level irrigation policy and investment strategies. By applying PRISM, decision-makers were able to target systems mostly in need of modernization, optimizing resource allocation and achieving more sustainable outcomes.
Remote sensing and drone technology can be leveraged to guide irrigation scheme modernization and enhance water-use efficiency. Box 8 shows how such technology was used in Lebanon.
Box 8Enhancing water-use efficiency through remote sensing drone technology in Lebanon
In the Akkar region of Lebanon, the El-Bared Canal system – a primary irrigation source for approximately 42 000 ha of land – suffers from severe infrastructure decay and pollution due to human interference and limited maintenance. The Rehabilitation of El-Bared Canal Irrigation System project, funded by the Government of Norway, was implemented to revitalize agriculture in the region. A significant component of the project was irrigation infrastructure modernization, leveraging remote sensing technology, particularly through drone-based damage assessment to enhance water-use efficiency.
Using quadcopters (drones), high-resolution orthophotos of the canal bed were taken to assess the rehabilitation needs of the Akkar irrigation canal. An image-processing algorithm was developed to analyse the requirements by differentiating between damaged and undamaged surfaces. A topographic survey was conducted to validate the process by overlaying drone data with actual structural measurements. The approach produced precise and scalable data, revealing a clear pattern of increased canal damage in areas of high population density and increased human interaction with the irrigation infrastructure for accessing water.
Lessons learned:
- Data accuracy – High-resolution imagery and optimized altitudes significantly enhanced image quality and the accuracy of analysis, and optimized cost-effectiveness.
- Process automation – The success of automated image segmentation shows potential for wider application in the assessment of large-scale irrigation systems.
- Adaptability – Remote assessment proved essential for continuous monitoring of inaccessible sections of the irrigation system facing infrastructure decay and pollution challenges.
Scaling up across large irrigation networks could help to enhance water management in irrigation schemes, increase agricultural productivity and improve resource-use efficiency.
Developing a holistic benchmarking approach for irrigation modernization
Irrigation modernization demands a comprehensive benchmarking approach that goes beyond mere technical upgrades. While structural modifications – such as transitioning from open canals to pressurized piping, and automating water release systems – represent significant advances, the success of these innovations hinges on various interrelated factors. To truly realize the potential of irrigation modernization, the benchmarking approach must encompass four main types of factors: technical, institutional, socioeconomic and environmental (see Box 9). A comprehensive analysis of these factors facilitates the identification of effective strategies that address the complexities of irrigated agriculture, ultimately fostering resilience and long-term success in modernized irrigation systems.
Box 9Four factors for successful irrigation modernization benchmarking
Technical. The underperformance of aged irrigation schemes around the world can be attributed to a range of technical factors that significantly hinder their effectiveness. Many of the technologies introduced during the initial design phase are no longer appropriate for local conditions, leading to inefficient water delivery and widespread water wastage. Poor infrastructure maintenance often results in substantial water losses, compounding the challenges faced by farmers. To address the technical shortcomings, modernization plans should include appropriate irrigation technologies, alongside a comprehensive rehabilitation of existing infrastructure. Integration of technical capacity-building programmes for farmers about water-efficient technologies can also enhance irrigation performance, ensuring that they are better equipped to manage their water resources effectively.
Institutional. In the past, irrigation schemes were operated under top-down management structures, limiting users’ participation. Centralized management often results in information gaps between decision-makers and the realities on the ground, leading to ineffective water allocation and management. The governance of local institutions responsible for managing water resources, such as water users’ associations (WUAs), is often weak, lacking the authority and resources necessary to operate effectively. This inadequate institutional capacity can lead to inequitable service delivery and may result in conflicts over water use. Fragmented policy frameworks further complicate these issues, as inconsistent regulations hinder the coordination necessary for effective water management. Empowering local communities and strengthening WUAs or farmers’ associations through capacity-building initiatives and appropriate local institutional frameworks should be central to all modernization efforts and included in any benchmarking exercise. Creating integrated institutional frameworks that align water management with food production goals can also foster better coordination among stakeholders, ultimately improving the overall management of irrigation systems.
Socioeconomic. Contributing to the challenges facing irrigation are a range of socioeconomic factors such as poor market access. Weak market linkages often prevent farmers from selling their produce competitively, diminishing their motivation to invest in improved irrigation systems. Improving market infrastructure to facilitate better access to markets will motivate farmers to adopt more efficient irrigation practices. In many cases, lack of landownership and insecurity of tenure deter farmers from investing in irrigation infrastructure or adopting new practices due to fears of losing access to land. Modernization should involve land tenure reforms to provide farmers with secure land rights, encouraging long-term investments in irrigation. Furthermore, smallholder farmers typically encounter significant barriers when seeking financial support, making it difficult for them to access the finance they need to upgrade their irrigation systems. Establishing financial support mechanisms, such as subsidized loans or grants, can help smallholders to access the resources they need to enhance their irrigation systems, ultimately leading to more sustainable agricultural outcomes.
Environmental. In modernizing irrigation systems, it is essential to prioritize environmental safeguards in order to enhance sustainability. Key considerations include conserving biodiversity by protecting local ecosystems and maintaining habitat corridors, as well as ensuring better water quality through monitoring and integration of ecosystem-based solutions (vegetative buffers) to filter contaminants. Additionally, integrating climate adaptation strategies, engaging local communities in decision-making and adopting integrated water resources management approaches can promote resilience to climate change. Finally, using renewable energy sources for irrigation operations can significantly reduce greenhouse gas emissions, contributing to a more sustainable agricultural future.
