Introduction

As water is the font of life, irrigation has been the font of civilization. It underlay the rise of the first sedentary societies organized on a large scale, in Mesopotamia, Egypt, the Indus Valley and China. Irrigated agriculture appears to have been developed as early as the 7th century BC, on a small scale, in sites such as Jericho and the settlement of Catal Huyuk, in what is now southern Turkey. Primitive methods of irrigation were also developed at approximately the same time by the early Sumerian people at the mouths of the Tigris and Euphrates Rivers. It was the Sumerians who were later to construct the first large-scale irrigation systems, between those two great rivers, to the north west of their original settlements. Historians agree that by approximately 3500 BC extensive irrigation systems were operated by several Sumerian city-states. The development of irrigation and water control measures in the other

1. Grateful acknowledgment is made of detailed suggestions on this chapter by Fernando Pizarro of the FAO and helpful discussion of some of its points with Alvaro Balcazar of the National University of Colombia.

Agricultural Development Policy Concepts and Experiences. R. D. Norton

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great river basins mentioned above followed soon afterwards, within about 300 years.2

Irrigation also has been the basis of much of the agricultural growth in the 19th and 20th centuries, from the Western United States and the deserts of Northern Mexico and Peru to Mali and Sudan, to the Punjab and China and South East Asia. Flood control has been equally essential for agriculture in many places, especially in China and India but also in other locations such as the northern coastal valleys of Honduras. Drainage is important everywhere irrigation is practiced, and even without irrigation it is vital in Northern Europe, where winter's precipitation leaves vast quantities of standing water that must be removed from fields in order for cultivation to take place. In brief, in most parts of the world water control is a major component of agricultural technology and a basic determinant of the sector's prospects for expansion.

It has been estimated that '2.4 billion people depend on irrigated agriculture for jobs, food and income [and] over the next 30 years, an estimated 80 percent of the additional food supplies required to feed the world will depend on irrigation'.3 In playing this fundamental role in food production, irrigation has become the world's largest user of fresh water, accounting for more than 80% of water use in Africa4 and comparably high percentages in other developing regions of the world. For low-income countries as a whole, in 1992 irrigation accounted for 91 % of water withdrawals, while for medium-income countries the corresponding figure was 69%.5

In the past, many irrigation strategies tended to treat water as an inexhaustible resource, and the emphasis was placed on the construction and financing of new systems to serve farmers. Now, the growing demands for water in all sectors have made it clear that water is a scarce resource, increasingly so, and former irrigation strategies are no longer viable in many areas. Ever larger numbers of countries are seeing their annual renewable water supplies fall below the critical level of 1000 m3 per capita, below which they become a severe constraint on development prospects. Some of those countries, and their projected renewable water supplies per capita for the year 2000, in cubic meters, are as follows: Saudi Arabia (103), Libyan Arab Republic (108), United Arab Emirates (152), Yemen (155), Jordan (240), Israel (335), Kenya (436), Tunisia (445), Burundi (487) and Egypt (934).6

At least six other countries in Africa and the Middle East were projected to fall below the level of availability of 1000 m3 by 2000. In some cases, the renewable supplies are being supplemented by mining groundwater and/or by desalinization of sea water, but the former is not sustainable and the latter is expensive, prohibitively so for agriculture.

The per capita availability of renewable water supplies is declining by more than 25 % per decade in many cases. In some countries not yet at the critical level, those supplies are already below the level of 2000 m3, which signifies serious problems in some of their regions, especially in drought years. More than 40 countries were expected to be in this situation by the year 2000,7

2. For a readable, yet reasonably thorough, summary of these early developments, see The Age of God Kings, Time-Life Books, Arlington, VA, USA, 1987.

3. FAO, 'Water Policies and Agriculture', in The State of Food and Agriculture 1993, Food and Agriculture Organization of the United Nations, Rome, 1993, p. 233, based on information from the International Irrigation Management Institute.

4. The World Bank, A Strategy for Managing Water in the Middle East and North Africa, The World Bank, Washington, DC, USA, 1994, p. 69, on the basis of estimates by the World Resources Institute and the World Bank.

5. World Bank, World Development Report 1992, The World Bank, Washington, DC, USA, 1992, p. 100, on the basis of data from the World Resources Institute.

6. FAO, 1993, p. 238. These figures include river flows from other countries, some of which may not be reliable sources in the future.

7. FAO, Reforming Water Resources Policy, FAO Irrigation and Drainage Paper No. 52, Food and Agriculture Organization of the United Nations, Rome, 1995, p. 7.

including Peru,8 South Africa, Zimbabwe, Morocco and Iran.9 By contrast, the average availability of water per capita in the world is much higher. By region, it was about the following levels (in m3) by the year 2000: Africa, 5100; Asia, 3300; Latin America, 28300; Europe, 4100; North America, 17 500.10 Endowments of fresh water supplies are not distributed spatially in a very even manner, neither within or between continents, nor within most countries. Since it is a product with low unit value, water is expensive to transport long distances from deficit to surplus areas. Therefore, most solutions to water problems have to be developed locally, specifically at the level of watersheds and groundwater basins.

Even in countries with relatively abundant supplies of water for the time being, irrigation is losing its former attractiveness for two other reasons: its productivity in terms of farm income has turned out to be substantially less than expected in many cases, and the cost of building irrigation systems has increased. In combination, these two factors mean that the economic returns to irrigation systems are often below levels that are considered acceptable.

It has been pointed out that the initial analysis of most African irrigation projects would not have looked promising if more realistic figures on expected yields, costs, scheduling of irrigation and other factors had been used in the calcula-tions.11 In addition, for a sample of irrigation projects analyzed ex post in Vietnam, Thailand, Myanmar and Bangladesh, it was found that their financial and economic returns were substantially reduced by below-target production levels and crop prices that turned out lower than expected. As a consequence, the sustainability of the schemes was weakened by factors completely unrelated to requirements for operation and maintainance (O & M).12

Irrigation management also has been deficient in many instances. The FAO has concluded that, on a world scale, 'The overall performance of many irrigation projects has been disappointing because of poor scheme conception, inadequate construction and implementation or ineffective management'.13 The International Irrigation Management Institute (IIMI) has underscored these problems:

. . . there is widespread dissatisfaction with the performance of irrigation projects. This is true whether performance is measured in terms of achieving planned targets or in terms of the production potential created by physical works. Sub-optimal performance can be observed in irrigation systems of all types and sizes, from the small farmer-managed systems in the hills of Nepal to the giant canal systems of India and Pakistan.

In most schemes around the developing world, more water is delivered per unit area than is required, leading to low irrigation efficiencies. According to a recent report, irrigation efficiencies are as low as 20-25 percent in Java, the Philippines and Thailand, and in Pakistan it is about 50 percent In many irrigation schemes, the actual irrigated area is much less than the area commanded. Water deliveries rarely correspond in quantity and timing to crop requirements, resulting in low cropping intensities and low productivity.

Sharp inequities in water supplies to farmers in the head reaches of the irrigation system and

8. Inter-American Development Bank, 'Nuevas Corrientes en Manejo de Aguas', El BID, August 1997, p. 4.

9. (a) Ruth S. Meinzen-Dick and Mark W. Rosegrant, 'Managing Water Supply and Demand in Southern Africa', in Lawrence Haddad (Ed.), Achieving Food Security in Southern Africa: New Challenges, New Opportunities, International Food Policy Research Institute, Washington, DC, USA, 1997, Chapter 7, p. 204; (b) The World Bank, 1994, op. cit., p. 69.

11. J. R. Moris and D. J. Thom, Irrigation Development in Africa, Westview Press, Boulder, CO, USA, 1991, p. 579.

12. E. B. Rice, Paddy Irrigation and Water Management in Southeast Asia, A World Bank Operations Evaluation Study, The World Bank, Washington, DC, USA, 1997, p. 52.

those located downstream are another manifestation of poor performance in many irrigation systems.14

In many irrigation systems, considerable amounts of water are wasted because they are withdrawn from the water source (e.g. well, reservoir, river, etc.) but only a portion of them are actually applied to the crops. For Latin America and the Caribbean as a whole, it has been calculated that this ratio of water applications to withdrawals averages 45%.15

System deterioration further reduces the efficiency of irrigation and is a common problem in irrigation facilities, especially in economies in transition. A clear illustration of this danger is provided by the experience of irrigation in Dashowuz Velayet, Turkmenistan:

Canal leakage is a major problem with delivery efficiencies ranging from 50 to 60 percent.. . . these low delivery efficiencies force excessive diversions in order to meet irrigation requirements. That increases the leakage and contributes to the high water table and, consequently, to the increasing soil salinity.

The ability to deliver precise amounts of water is also limited by the condition of the control gates.. . . However, many of the drive motors are inoperable or even missing. Many of the threaded shafts that control the gates indicate that the positions of the gates have not been changed in a long time. There is no evidence of lubrication and they are heavily rusted. A few of the shafts were even bent to the degree that they could not be adjusted.. . .

In the Yilany Etrap, it was reported that the entire area is served by pumping from the Shabat Canal. However, only 40 to 50% of the pumps are operational. Repairs are funded by the budget, but there are not enough funds for parts and maintenance

Increasing soil salinity caused by high water tables is the primary direct cause of low crop productivity. The primary on-farm water supply-related cause is excess application of irrigation water coupled with inadequate on-farm drainage systems.. . .

Problems with [the drain] collectors are primarily siltation and depth. Siltation is a continuing problem that reduces the capacity of the collectors and the collectors are too shallow to adequately receive water. . .. The World Bank also states that these drains have been neglected to the point that most open drains are silted and overgrown with weeds and the closed drains have not been flushed for years and almost all are reported to be non-functional.16

Deterioration of irrigation works also has been occurring widely in Kazakhstan:

It is estimated that irrigation systems in the country use 30-35 % more water than irrigation systems growing similar crops in market oriented economies. In recent years irrigation system efficiency declined even further as most irrigation systems have deteriorated due to a lack of funds for maintenance and a breakdown in management.

Farm privatization and restructuring in the sector have created further problems. The rapidly increasing number of small farms has made irrigation management more complex involving financial, economic, environmental and institutional issues. State and district level water committees are facing increasing difficulties in terms of water fee collection and revenue generation. The inefficient use of the irrigation

14. International Irrigation Management Institute, 'The State of Irrigated Agriculture', in 25 Years of Improvement, at the worldbank/cgiar website, 1998 [www.worldbank.org/cgiar].

15. Luis E. García, Integrated Water Resources Management in Latin America and the Caribbean, Sustainable Development Department, Environment Division, Inter-American Development Bank, Technical Study No. ENV-123, Washington, DC, USA, December 1998, p. 8.

16. Adrian O. Hutchens, 'Irrigation Management and Transfer Issues in Turkmenistan', prepared for Central Asia Mission, US Agency for International Development, April-May 1999, pp. 8-10.

systems has exacerbated local environmental problems with excessive water applications leading to water logging and salinity problems, as well as contributing to downstream environmental problems in the Aral and Caspian Seas.17

Centralized control of irrigation systems everywhere has tended to lead to system deterioration. A similar litany of deficiencies was reported for Andhra Pradesh in India, before the devolution of responsibilities for maintenance to the farmers themselves:

.. . the number of control structures at various levels of the systems is insufficient and communications systems are rudimentary. The most detrimental factor, however, has been the cumulative impact of chronic underfunding of maintenance over many years. This has resulted in the severe disrepair of most surface irrigation schemes: canals and drains are heavily silted, lined sections are damaged, drops are eroded and collapsing, many gates are inoperative, outlets are damaged, and shutters are missing. . .. Irrigated yields and production per unit of water are well below their potential. .. . Inequitable and unreliable water delivery from deteriorating systems has resulted in tail enders not getting water and yield shortfalls for other farmers ranging from 15% to 40%.18

Policy makers should be aware that irrigation projects can fail badly. Sometimes, it is more than a question of low returns on an investment. The Bura project in Kenya is one of the prime examples of irrigation gone very wrong. It was expected to be a showcase of agricultural development, and original estimates suggested that

100 000 ha or more could be irrigated along the Tana River, and then an early feasibility study suggested implementing the scheme on 18000ha. In the end, only 3900ha were made operational, which meant that the high capital costs could not be recovered. There were more serious problems, however. As W. M. Adams has summarized them, they included:

. .. low yields, both of maize and cotton, and resulting low settler incomes. The chief cause of this has been poor and erratic water supply. .. . Problems of maintenance, spare parts, fuel supply, and lack of trained operators and mechanics led to repeated breakdowns in 1983 and 1984, during which year water was unavailable for 25% of the time. . . . siltation of structures and canals, and in places erosion of the main supply canals, have been significant. .. . Malnutrition in children was a serious problem. . .. the Health Center, finished in 1981, was not opened until 1983 due to budgetary constraints in the Ministry of Health. .. . Disease incidence was high among settlers and their children during this period, particularly because of cerebral malaria. The construction of tenant houses fell behind schedule, and their cost rose, making the possibility of tenants being able to afford to repay those costs more remote.. . . Furthermore, shoddy workmanship led to the collapse of many houses (34% in Village I in 1982, for example). .. . There were also serious problems of fuelwood supply. ... In technical terms, it was clear that the poor soils of the project area were a serious constraint, resulting in low economic returns. . .. Bura will continue to suffer operational deficits. Furthermore, tenant incomes are so low that it will not be possible to raise service charges to meet the shortfall.19

17. Sam Johnson, 'Economics of Water Users Associations: The Case of Maktaral Region, Southern Kazakhstan', prepared for Central Asia Mission, US Agency for International Development, November 1998, p. 4.

18. Keith Oblitas and J. Raymond Peter, Transferring Irrigation Management to Farmers in Andhra Pradesh, India, World Bank Technical Paper No. 449, The World Bank, Washington, DC, USA, 1999, pp. 5-6.

19. W. M. Adams, 'How beautiful is small? Scale, control and success in Kenyan irrigation', World Development, 18(10), October, 1990, pp. 1317-1318.

Similarly disappointing stories could be recounted for other projects in various parts of the world. Thus, at a juncture in world history when the potential contribution of irrigation is ever more necessary and valuable, the barriers to the realization of that contribution have become formidable. For this reason, new emphases and approaches for irrigation strategies have emerged in the past decade or so, and a principal purpose of this chapter is to synthesize them and underscore the issues that are involved. A related purpose is to provide references to technical studies in the field that the interested reader can consult further.

While the problems of irrigation are difficult ones, the international consensus is that the problems can be overcome and that irrigation has an important role in the future. As the FAO has put it:

The mediocre performance of the irrigation sector is also contributing to many socioeconomic and environmental problems, but these problems are neither inherent in the technology nor inevitable, as is sometimes argued.

Irrigation projects can contribute greatly to increased incomes and agricultural production compared with rainfed agriculture. In addition, irrigation is more reliable and allows for a wider and more diversified choice of cropping patterns as well as the production of higher-value crops. Irrigation's contribution to food security in China, Egypt, India, Morocco and Pakistan is widely recognized. For example, in India, 55 percent of agricultural output is from irrigated land. Moreover, average farm incomes have increased from 80 to 100 percent as a result of irrigation, while yields have doubled compared with those achieved under the former rainfed conditions; incremental labor days used per hectare have increased by 50 to 100 percent. In Mexico, half the value of agricultural production and two-thirds the value of agricultural exports [are] from the one-third of arable land that is irrigated.20

There is no other single technology or policy intervention in agriculture that promises benefits of the magnitudes that irrigation does, provided its potential can be realized.

In spite of the widespread emergence of problems in irrigation systems, there are a number of 'success stories' which bear out the FAO's optimism that, with proper policies, irrigation can improve its efficiency and continue to provide many economic and social benefits. The FAO has pointed to the experience of the Philippines as one example of how the management of irrigation systems can be reformed with positive results:

The National Irrigation Administration (NIA) of the Philippines is a good example of how a bureaucracy can, over time, transform its strategy and operating style. .. . The quality of the irrigation service provided by and for farmers has undoubtedly improved, system operating expenses have been reduced and the recurrent cost burden of the scheme on the national budget has been eliminated. .. . Recent research suggests that the reforms have made water supply more equitable.21

Sharma et al. have highlighted selected cases of successful irrigation management in Nigeria, Ethiopia and Mali:

Fadama irrigation in Nigeria: Fadama are river valley areas which are seasonally flooded or have high water tables for all, or a large part, of the year. .. . The projects made available motor pumps at subsidized prices, and drilled tubewells, which enabled farmers to greatly increase water use for dry season crop production. These systems each allowed irrigation on 1-2 hectares at a cost of US$3 50-700 per hectare. Individually owned and maintained, 70 percent of farmers in project areas use the pump systems, and the schemes have a 90 percent success rate. .. . with over 50 000 pumps operating nationwide, a strong service

20. FAO, 1993, p. 233, in part on the basis of estimates from the International Irrigation Management Institute.

industry has developed to maintain them, ensuring sustainability.

Ethiopia's success with small scale participatory irrigation:. . . the project provided funds for rehabilitation and construction of over 4400 hectares of small-scale irrigation schemes (with average investment costs of $1200 per hectare). .. and technical assistance support to the Irrigation Development Department at national and regional levels.. . . Over 40 water user groups voluntarily formed at the time of initiation then fully participated in scheme identification and construction. These groups have also assumed total responsibility for operation and maintenance. Income generation and growth have resulted in project areas, and 100 personnel have been provided with training.

Spectacular success in the Office du Niger: The Office du Niger (ON) in Mali began in 1932 as a French scheme to produce cotton and rice in a one million hectare area over a fifty year period. However, in 1982, the project was far from meeting its objectives: only 6 percent of the target area had been developed . . . infrastructure was poorly maintained, cotton production had been discontinued, average paddy yield was at a low point, and settlers were unhappy. However, after 10 years of careful [project] preparation and implementation, the ON is on its way to becoming a success.. . . between 1983 and 1994: average paddy yields have tripled, 10 000 ha of abandoned land have been rehabilitated, the settler population grew by 222 percent, and per capita production of paddy rose from 0.9 tons to 1.6 tons farmers were allowed to participate more fully with the ON (e.g. through the setting of fees and collection of payments). Additionally, the ON itself has been restructured and stream-

lined, and fee collection has reached a level of

97 percent (even with an increase of 43 percent

[in rates] over the last two years).22

These excerpts suggest some of the factors that can contribute to success in irrigation schemes. They and other factors are reviewed systematically in this chapter.

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