Comparative Indicators for Irrigation
System Performance

Comparative performance indicators make it possible to see how well irrigated agriculture is performing at the system, basin or national scale. As a tool for measuring the relative performance of irrigation systems or tracking the performance of individual systems the IWMI comparative performance indicators help:

• Policy makers and planners to evaluate how productively land and water resources are being used for agriculture, and to make more informed strategic decisions regarding irrigation and food production.
• Irrigation managers to identify long-term trends in performance, to set reasonable overall objectives and to measure progress.
• Researchers to compare irrigation systems and identify factors that lead to better performance.
• Donor agencies, governments and NGOs to assess the impact of interventions in the irrigation sector and to design more effective interventions.

Why Comparative Indicators?

The amount of water and land available for agriculture is limited, and in many developing countries, with the growth of cities and industries, it is shrinking rapidly. Irrigated agriculture worldwide must improve its utilization of these increasingly scarce resources.

The comparative performance indicators enable policy makers and planners to see how productive their use of water and land for agriculture is. They help answer important strategic questions, such as: What types of systems are getting the most from limited water and land resources? How much should we invest in irrigated agriculture, and how? At the same time, they provide a cost-effective means of tracking performance in individual systems.

How can you use Comparative Indicators?

Comparative indicators give a broad overview of the hydrological, agronomic, economic, financial, and environmental performance of irrigation systems. Because they focus on elements common to all systems-water, land and crop production-they make it possible to compare systems with different infrastructures, management types and environments. They are also a suitable tool for comparing performance in a single system over time or different areas of the same system. They require a limited amount of data that is generally available and readily analyzed, and so can easily be incorporated into regular evaluation procedures.

Setting standards for performance

One of the challenges of improving irrigation performance is answering the question: how well should a system be performing? Judgment of performance requires some standard of comparison. Measuring the performance of a system relative to other similar systems helps to identify 'performance gaps' and, in some cases, to suggest possible causes for poor performance. Based on the information provided by the comparative indicators, irrigation managers can use 'internal' or 'process' indicators to home in on the problem and find solutions.

Irrigation managers can also use these comparative indicators to identify long-term performance trends within their system-making it easier to set achievable objectives. They can also see how well different areas of the system are performing relative to each other to identify areas of inequity.

Measuring the impact of irrigation-sector interventions

Comparative performance indicators provide a reliable method for measuring the impact of changes in irrigation management, farming practices, and system design. These indicators are particularly useful for evaluating the impact of irrigation-sector interventions because they make it possible to:
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• Easily monitor performance over time.
• Assess the effects of far-reaching irrigation policy, such as irrigation management transfer, on multiple systems.
• Measure the impact of institutional and management reforms that are not easily quantifiable.

Comparative indicators can be used to assess the impacts of multiple factors on irrigation systems over time. When the indicators were applied in Turkey's Gediz Basin, they revealed that irrigation performance actually improved during the drought of 1988-1994. The drought forced irrigation managers to make changes in water allocation and distribution. Farmers reacted by investing in groundwater development and switching to higher-value crops with lower irrigation requirements. Because of these changes, the output per unit of water increased and the output per unit of land remained constant, despite the shortage of water.

Uncovering the keys to better performance

As more information is collected from systems around the world, comparative performance indicators are providing important clues to the determinants of irrigation performance. They allow researchers and planners to identify systems that are performing relatively well or relatively poorly, and to target these systems for further study.
These indicators are helping to answer the question: How is performance related to key features of irrigation systems, such as: infrastructure (fixed or flexible); management (agency, farmer, or joint); allocation and distribution procedures (supply versus demand-led); climate (wet or dry); and socioeconomic setting (large or small holdings)? This information can be used to design better irrigation systems and guide management reform and rehabilitation efforts in existing systems.

How the Comparative Indicators work

The Standardized Gross Value of Production (SGVP) makes it possible to compare the performance of systems, no matter where they are or what kind of crops are being grown. Output per unit of water used to grow oranges in Mexico can be compared with that of water used to grown apples in Nepal. The SGVP captures both local preferences-for example, specialized crops that may have a low international price, but a high local value-and the value of non-traded crops.

An introduction to the Indicators

How productively are land and water being used? The first four indicators relate the monetary value of the system's final output, agricultural production, to the inputs of land and water. By standardizing the gross value of agricultural production (see above box) and relating it to inputs common to all systems (land and water), these indicators make it possible to compare the performance of radically different systems. Where water is scarce, the SGVP per unit of water consumed (by crop evapotranspiration) is particularly useful. Where land is the scarcer resource, output per unit of cropped area or command area is more pertinent.
Output per cropped area =	SGVP Irrigated cropped area
Output per unit command =	SGVP Command Area
Output per unit irrigation supply =	SGVP Diverted irrigation supply
Output per unit water consumed =	SGVP Volume of water consumed by ET
Is there enough water available to meet crop demand? The relative water supply relates the water made available for crops, including surface irrigation, groundwater pumped and rainfall, to the amount crops need. When the crop is rice, the water 'lost' to seepage and deep percolation through the soil is considered when calculating crop demand, This indicator provides information about the relative abundance or scarcity of water.
Relative water supply =		Total water supply Crop demand
Are crops getting enough water or too much? The relative irrigation supply indicates how well irrigation supply and demand are matched-a value over 1 would suggest too much water is being supplied, possibly causing waterlogging and negatively impacting yields; a value less than one indicates that crops aren't getting enough water.
Relative irrigation supply =		Irrigation supply Irrigation demand *irrigation supply includes only surface diversions and pumped groundwater.
Is irrigation system design constraining agricultural production? The water delivery capacity can suggest changes in irrigation infrastructure or cropping patterns are needed to maximize cropping intensity.
Water delivery capacity (%) =		Canal capacity to deliver water at system head Peak consumptive demand
Is irrigation a good investment in a given environment? The gross return on investment indicates broadly whether irrigation infrastructure was a good investment in a particular context, or not. As this indicator is applied to more systems, it is giving planners and policymakers information on how, where and how much they should invest in irrigation.
Gross return on investment (%) =		SGVP Cost of irrigation structure
Is the system financially sustainable? The financial self-sufficiency indicator shows how much of the money spent on operations and maintenance is generated locally. Assuming operations and maintenance expenditures are sufficient to meet actual needs, this indicator can determine the financial sustainablility of the system). The financial self-sufficiency indicator is particularly important for gauging the impacts of irrigation management transfer, where the primary goal is to transfer financial responsibility for the system from the government to the farmers.
Financial self-sufficiency =		Revenue from irrigation service fees Total O&M expenditure

Useful Publications

The IWMI Research Report 20, Indicators for comparing performance of irrigated agricultural systems, introduces the indicators and states the rationale behind them.

Assessing irrigation performance with comparative indicators: The case of the Alto Rio Lerma Irrigation District, Mexico (IWMI Research Report 22) describes the application of the indicators and compares this with the application of a small set of process indicators.

Indicators of Land and Water Productivity in Irrigated Agriculture introduces the first four indicators, illustrates four typical applications of the indicators and describes the results of a study of 40 irrigation systems using the Indicators

• SAKTHIVADIVEL, R.; DE FRAITURE, C.; MOLDEN, D. J.; PERRY, C.; KLOEZEN, W. 1999. Indicators of land and water productivity in irrigated agriculture. International Journal of Water Resources Development, 15(1/2):161-179.

Why Comparative Indicators

How can you use Comparative Indicators?

Setting standards for performance

Measuring the impact of irrigation-sector interventions

Uncovering the keys to better performance

How do Comparative Indicators work?

An introduction to the Indicators

Useful publications