FAO INVESTMENT CENTRE
Technical Paper N. 11

Guidelines for Planning Irrigation
and Drainage Investment Projects

1996

Table of Contents

FOREWORD

Objective of the Guidelines

INTRODUCTION

PART 1: RECENT LESSONS AND IMPLICATIONS FOR PLANNING

1. Irrigation in the Context of Water Resources Management

2. Irrigation Types and the Issue of Scale

3. Irrigation, Food Supply and Drought

4. Effective Implementation

5. Fiscal Sustainability

6. Water User's Associations

7. Social and Environmental Aspects

8. Choice of Technology

9. The Drainage Dilemma

10. Implications for the Planning Process

Further reading

Footnotes

Publicly financed irrigation and drainage investment projects have too often performed poorly. Sometimes the reasons have been unforeseeable or unavoidable. But in some cases shortcomings were because planners gave inadequate consideration to institutional constraints or to the practical problems of subsequent implementation, or because there was insufficient commitment by governments or users to the developments proposed. Delay, dilapidation, waste of scarce water and adverse social and environmental impacts have been among the familiar consequences. Lessons have been learned from these setbacks, however. These Guidelines give prominence to the planning approaches which have evolved, and are still evolving, to avoid future difficulties. The publication stresses sounder formulation of irrigation and drainage investment strategies, improved conceptualization of project options, and building stronger participation and commitment into the detailed planning process. The intended users are FAO Investment Centre staff, trainees and consultants, as well as local planning groups set up by governments to prepare investment proposals. Some of the material may also be useful to consulting firms and financing institutions involved in planning or appraising such projects. The following Investment Centre Technical Papers complement and should be read in conjunction with these Guidelines: Guidelines for the Design of Agricultural Investment Projects (No. 7, revised 1995); Financial Analysis in Agricultural Project Preparation (No. 8, 1991); and Guidelines on Sociological Analysis in Agricultural Project Design (No. 9, 1992).

The objective of these Guidelines is to summarize present thinking and practice, and to assist practitioners to plan irrigation investment projects and programmes that will realize and sustain their full potential. They cover the whole investment planning process, from formulation of subsectoral strategies, to conceptualization of project options, and detailed planning of the preferred option(s).

Why New Guidelines?

Irrigated agriculture has made a major contribution to food production and food security throughout the world: without irrigation much of the impressive growth in agricultural productivity over the last 50 years could not have been achieved. Nevertheless it is widely accepted that the overall performance of ‘irrigation and drainage’ (also implying reclamation and water control) investments has too often fallen short of the expectations of planners, governments and financing institutions alike (Ref: Report No. 13676, A Review of World Bank Experience in Irrigation, Operations Evaluation Department, World Bank, Washington DC, 1994).

 In 1992, the World Bank's Portfolio Management Task Force reported that major problems that constrain the performance of World Bank financed investment projects in various sectors, are: 

• inadequate consideration of institutional constraints and poor planning for implementation; and 

• a lack of commitment to the success of the project by governments and users. 

• In the case of irrigation investments these problems are manifested in poor project management, both at implementation and thereafter, and poor operation and maintenance resulting from inadequate budget allocations or from rent seeking by users and officials. These core problems usually give rise to, or are accompanied by, a host of other technical, social and economic problems, such as:

•  implementation delays and cost overruns;

•  premature degeneration of civil works and equipment;

•  unreliable water supplies, or over-irrigation, waterlogging and salinity;

•  social problems, including problems of organization, equity, land tenure and gender exclusion;

•  lower than expected output values, due to poor technical performance or reflecting over-optimistic price projections by planners.

The World Bank Task Force stressed that the ultimate success of a project is to a significant degree determined by what happens in the "upstream" planning process, and that many implementation problems can clearly be traced to deficiencies here. These findings are now considered generally valid by other international financing institutions and donors. The lessons learned regarding these problems, and the new approaches that have been developed to tackle them, therefore make new guidelines essential and timely. 

Since the ultimate success of an investment is largely determined by the quality of the upstream process of planning, it is pertinent to examine recent lessons learned from experience and their implications for future planning. The main lessons are that water is an increasingly scarce resource for which there are many competing demands that are more profitable, socially and economically, than irrigation; also that low world prices for basic food and fibre crops, together with typically high development costs, have recently made new irrigation development increasingly difficult to justify. Even so, world food supply will depend even more on irrigation in the next century than in the present. Future irrigation investment must therefore focus on lower cost solutions, both for new development and for rehabilitation, on making better use of existing irrigation facilities and on increasing output value per unit of water used. Planners should seek to establish the conditions that will promote this focus. 

In recent years, water issues have been the focus of increasing international concern and debate ⁽¹⁾. More than two thirds of the water withdrawn from the earth's rivers is used for irrigated agriculture; in developing countries the proportion is even higher - more than 80 percent. But agriculture is a relatively low-value and often highly subsidized water user. Competition for water with other sectors is already constraining economic development in many countries; as populations expand and economies grow this competition will intensify, as will conflicts between water users, or between countries where such competition transcends international borders.

Cities and industries can afford to pay more for, and earn a higher economic rate of return from, a unit of water than agriculture. Hence governments and financing institutions are being forced to reconsider the economic, social and environmental implications of investment in irrigation. As a result, it is likely that in future the water sector will be less dominated by irrigation, and in some countries water formerly used for agriculture is already being reallocated for higher-value uses.

The 1993 World Bank policy paper Water Resources Management crystallized much of the thinking of governments and financing institutions with regard to the overall management of water resources. It called for new approaches, including demand management, - that is to say the use of economic, legal, institutional and other policy interventions to influence the demand for water in order to improve the efficiency of its use. In countries with significant water management problems, the international financing institutions increasingly require the preparation of inter-sectoral water resources management strategies to guide the lending programme in the water sector, as a precondition to lending for irrigation. The implication is that loans for irrigation development will not be made where this will prejudice other more profitable or socially desirable uses of water.

These Guidelines, however, start from the assumption that water policy reviews have indicated that irrigation is a justifiable option within the context of a country's overall water resources management strategy, and that investment finance could be made available for its development. The Guidelines therefore do not address the principles and processes involved in water resources management strategy formulation, which are well covered elsewhere⁽²⁾. The need for project planning to be in strict conformity with such strategies nevertheless cannot be overemphasized.

2. IRRIGATION TYPES AND THE ISSUE OF SCALE

Irrigation Typologies

With about 250 million hectares irrigated throughout the world in vastly different climatic and socio-political environments, some categorization of irrigation may be thought desirable. Numerous typologies are commonly used, such as system size, the nature of the water source, and whether schemes are operated publicly or privately. Definition by size presents difficulties on a global level, since, for example, what might be considered large-scale in some countries in Sub-Saharan Africa would be considered as only small or medium-scale in South Asia. Furthermore, many of the problems confronting publicly financed irrigation transcend scale, and some attempts at categorization have confused "small-scale" with "traditional" or "informal" irrigation. Definition by the type or nature of the water source does not recognize the very different characteristics of major public surface water schemes based on dams in the USA, for example, and small community-managed tank irrigation schemes in Sri Lanka.

From the technical viewpoint, a further distinction can be made between rice schemes, which comprise more than half of the world's irrigation, and non-rice schemes, because of their fundamentally different characteristics. Since the rice plant tolerates waterlogging and needs much more water to thrive than almost all other of the major irrigated crops, it is dominant where water is cheap and plentiful, notably in the humid eastern side of South Asia eastward through to Japan and Indonesia. Non-rice projects are generally found in the drier or cooler parts of the developing world. The design and operation of a rice-growing irrigation system is significantly different from that for other crops: rice fields are waterlogged to reduce the weeding requirements, whereas crops such as wheat, maize and especially cotton will die under these conditions⁽³⁾. Once the crop is established rice schemes usually receive a small but continuous flow to maintain flooded conditions; field-to-field irrigation is acceptable because a down-catchment farmer will often use what an up-catchment farmer wastes. Irrigation systems designed for other crops do not usually suit rice very well, and vice-versa.

For the purpose of these Guidelines, irrigation could perhaps be categorized globally as either public or private, ie by the degree of end-users' commitment of resources to, and control over the operation of, the system, rather than the usual categorization by scale. Even this is difficult to define precisely, since the share of public versus private resources can vary widely between schemes. Nevertheless, public irrigation is defined here as any irrigation in which government has the dominant financial interest or management responsibility/control. Public irrigation may range in size from schemes of hundreds of thousands of hectares, down to very small schemes of 10 ha or less; but in each case these are initiated and developed under public authority and control, and operated and maintained in the same way. This definition includes for example state-owned large-scale estates (e.g. for sugar cane production), joint ventures between government and quasi-government financial institutions, and large-scale through to small-scale smallholder irrigation schemes set up under government authority.

Conversely, private irrigation can be defined as any irrigation in which farmers (or a private sector group) have the dominant financial interest or management responsibility/control. It includes: 

• Farmer-managed irrigation schemes of a few hundred square metres to a several thousand hectares, developed, operated and maintained by individuals, families, communities, or local rulers and landowners, independently of government, and generally for the production of basic food or fibre crops and vegetables for local markets. Examples may be found throughout the world, from small plots of paddy in Southeast Asia, shallow tubewells in the Indo-Gangetic Plain, tank irrigation systems elsewhere in South Asia, qanat systems in Iran, Afghanistan and Pakistan, the swamp and flood recession areas with partial water control in Sub-Saharan Africa, to spate irrigation systems in Southern Arabia. Some of these systems are hundreds of years old, in which case they are often referred to as traditional irrigation. 

• Commercial irrigation, with units ranging in size from a few hectares to several thousand hectares, financed, operated and managed by individuals or privately owned companies. This category would include for example localized⁽⁴⁾ irrigation systems of 1-2 ha in extent, for the production of flowers, vegetables or fruit, to larger overhead or surface irrigated schemes for the production high value field crops such as tobacco, and privately owned sugar estates. 

The most important differences between public and private irrigation as defined above are that: 

• in public irrigation it is the government that plans, finances and implements schemes, and in most cases farmers effectively receive a subsidized service; 

• in private irrigation, even though government may sometimes facilitate development or provide incentives, farmers take their own investment decisions, pay, implement, operate and maintain systems, and carry the risks. 

Public irrigation therefore tends to be supply-driven and may incorporate political or social objectives, while private irrigation is demand-driven and reflects financial objectives or, at times, the survival strategy of the poor. These characteristics impinge on many of the basic decisions for development planning and imply fundamental influences on the investment approach. The features that make successful private irrigation self-sustaining should if possible be emulated in planning public irrigation investments. Thus farmers must be involved in the planning decisions, contribute at least a part of the capital costs, and accept full responsibility for operation and maintenance (O&M). As will be seen, the planning and investment trend in publicly financed irrigation is to emulate those characteristics of private irrigation that make it generally self-sustaining.

The Issue of Scale

According to a World Bank review of its experience in irrigation⁽⁵⁾, there is no evidence to suggest that small-scale irrigation is more or less likely than large-scale to achieve success, judged in terms of sustained economic internal rate of return. Nevertheless, it can be argued that where irrigation institutions - public or private - are still relatively weak, where there is a lack of capacity to plan, implement, operate and manage large schemes, attention should focus on smaller developments. Smaller schemes are more conducive to farmer management and control, and market limitations for the crops produced often make such schemes the only viable choice. On the other hand, there are many examples of the development of small public irrigation systems, scattered over a wide area, that have overstretched the logistical and staffing capabilities of irrigation agencies and have eventually failed. In theory, larger developments should encourage more Government support, attract better management, be easier to organize, and therefore enjoy better prospects for sustainability.

There are numerous other arguments for and against large or small irrigation schemes: for example, the obvious economies of scale and multiplier effects of large schemes (see Box I-1). Many of the arguments are valid in some countries, for certain irrigation types, but not in others. Thus, generalization should be avoided and the issue of scale should be approached considering the individual circumstances of the project and institutional capacities in the country concerned. As will be seen, there are more important issues than scale: the overwhelming experience is that what is important in predisposing irrigation to success is the extent to which it enjoys the commitment of stakeholders⁽⁶⁾ to good engineering design, quality construction, efficient operation and adequate and timely maintenance. 

3. IRRIGATION, FOOD SUPPLY AND DROUGHT 

Options and Alternatives for Food Supply

As populations in some developing countries continue to grow faster than increases in food production, the options for meeting the consequent incremental demand for food need to be considered. These are discussed below. 

Although between 30 and 40 percent of the world's food at present comes from the irrigated 20 percent of total cultivated land, before contemplating further irrigation development the potential for increased food output from rainfed areas should be considered. There may be prospects for obtaining sustainable production increases under rainfed conditions through relatively simple low cost technologies: for example improved in situ water conservation techniques⁽⁷⁾, and the adoption of integrated pest management and integrated plant nutrient management strategies. However where land resources are scarce, further area expansion of rainfed food production could increasingly involve more marginal areas, with a risk of increased deforestation, soil erosion and general land degradation. In the less well-endowed areas particularly, the potential for stabilization or intensification of existing rainfed production by increased use of agrochemical inputs is also technically limited: either the possible gains have already been achieved, or they are unlikely to be achieved because of aversion by farmers to the known risks of investing in improved inputs in marginal rainfall areas. 

Hence, even though irrigation development cannot, and perhaps should not, be relied upon to meet the entire future increase in demand for food, supply can be expected to depend to an even larger extent on irrigation in the next century than it has in this. 

Increased production through new irrigation development is nevertheless increasingly difficult to justify economically for the production of basic foods, because of the decline in world market prices for these crops⁽⁸⁾ and typically high per hectare capital costs (see Box I-2, also Annex 2 of Investment Centre Technical Paper 5⁽⁹⁾). The situation may change in the longer term if, as world population grows, the demand for food begins to outstrip supply. In this case prices might reasonably be expected to approach the marginal cost of irrigated production, and the use of current World Bank price projections for project analyses may be inappropriate⁽¹⁰⁾. Indeed, should world market prices for basic food crops show signs of recovery, this could significantly alter the profitability of production of such crops under irrigation. Nevertheless, for the foreseeable future any expansion of irrigation for the production of basic foods will only be possible if substantial reductions in per hectare capital costs of new development can be achieved. 

In many countries, however, the better irrigation sites are already developed, and hence new projects could be expected to cost even more per hectare than those developed in the past. New irrigation development in these countries may therefore increasingly be justified only for the production of relatively high value crops - for which markets and marketing are often constraints - rather than for basic foods. In this situation markets, as much as the availability of suitable sites, will determine the pace of investment in new irrigation, unless lower cost technologies can be devised and introduced. This is today's challenge to irrigation engineers. 

Given that the cost of new irrigation development for food production is increasingly difficult to justify, and that many existing irrigation systems perform below potential, it is logical to consider intensification and increased output from existing systems. The investment emphasis in recent years has therefore shifted towards improving the latter, taking advantage of sunk costs to achieve incremental production at low incremental cost. It is important here to note the distinction that has been made between an endless cycle of rehabilitation, which is simply deferred maintenance, and upgrading, which involves making existing schemes work better. Upgrading usually calls for engineering, economic and sociological analysis to arrive at solutions. Sectoral loans aimed at such improvements have become an important part of the portfolios of the financing institutions, often linked to system management transfer to the users (see Chapter 7). 

The above discussion focuses on irrigation development in formal systems and takes no account of the existence, in various parts of the world, of large areas of informal or traditional irrigation. 

These, by definition, have been developed on the initiative of farmers rather than governments, and have continued their existence in the same way. Traditional irrigation systems are often characterized by poor water control, and consequent low cropping intensities and yields. In many cases improved water control can be achieved at comparatively low cost, and is often easily justified by the incremental production that can be achieved as a result. Thus, given that in some countries the area under traditional irrigation far exceeds the area under formal irrigation, the scope for obtaining increased food production from these systems could be significant. The identification of opportunities for such improvements may therefore be a priority for planners. However, it must also be noted that the most important feature of these systems is local initiative, responsibility and control; proposed improvements should avoid inadvertent transfer of responsibility to government. 

Apart from traditional irrigation systems, other opportunities exist for low cost irrigation, particularly for localized irrigation, including systems based on the use of clay pots for the storage and gradual release of irrigation water. These, and other similar devices, often bring nutritional benefits to local communities because they are generally used for fruit and vegetable production. They make efficient use of scarce water, but are in general unsuited to large-scale food production⁽¹¹⁾. 

In many regions of the world the major river systems have their headwaters in high rainfall or snowmelt areas and flows are relatively insensitive to droughts in agricultural areas downstream. Here the value of irrigation in "drought-proofing", by creating greater yield stability and out-of-season food production, is undoubted. 

In other areas subject to repeated and prolonged droughts, such as the Sahel, northeast Brazil or southern and eastern Africa, although at first sight there would appear to be no apparent alternative for improving local food security, irrigation does not always provide full insurance against drought. In much of Sub-Saharan Africa for example rivers and dams dry out and groundwater levels drop in years of recurrent drought. It could therefore be argued that in these circumstances irrigated agriculture is more vulnerable to drought than some less intensive forms of agriculture. Moreover, even where irrigation potential remains unexploited in these areas, its development cost nowadays will often only be justified by high value crops. These have limited markets and will bring primary benefits to only a few of the people normally at risk. Thus, despite its superficial appeal, irrigation development in these areas may not be a fully effective means to combat recurrent drought, rural poverty and food insecurity. There are unfortunately no easy, quick fixes for these problems. Further research is necessary, aimed at developing viable technical recommendations that take account of the recurrent drought cycle, including opportunities for non-farm rural employment. Policy assumptions that automatically equate irrigation development with the elimination of drought risks in such areas should be regarded with caution. 

4. EFFECTIVE IMPLEMENTATION 

Experience to date, well summarized in the 1992 report of the World Bank's Portfolio Management Task Force referred to earlier, makes it clear that a key condition for sustainable development impact from irrigation investments is implementability. This requires: 

• that the implementation requirements of the project are matched to local institutional capacity; 

• commitment to the project, built on stakeholder participation and local ownership. 

Other factors, such as good technical design, sound construction and financial viability for the users are of course equally important. But experience indicates that in the past irrigation professionals have often underestimated the attention which also needs to be given to implementability. 

The conventional project identification/preparation approach of the past has often resulted in arriving at detailed project design only to find a mismatch with local capacity to implement it. Money and technical assistance has then been provided to bridge the gap. Technical assistance frequently then crowds out any local capacity, and may in effect substitute for local management rather than strengthen it, bringing no sustainable improvement. 

In the conventional planning process, detailed start-up and implementation plans have generally been considered as beyond the ambit of the identification/preparation teams work. That this was inappropriate is now clear and a new approach has been found necessary: projects should be planned to match local capacity for implementation, which implies that planning teams should first acquire a thorough appreciation of this capacity. If necessary the project scope and content may be reduced to match existing implementation capacity. Technical assistance can then be applied selectively, rather than indiscriminately as often in the past, for genuinely sustainable capacity to be built. The planning process should therefore give specific attention to an analysis of institutional capacity, and to providing a detailed programme to enable the implementers to prepare themselves for carrying out the tasks expected of them, once the project becomes effective. 

Successful implementation requires participation in the planning and implementation process by all stakeholders, in order to create a sense of ownership of, and consequent commitment to, the project. This requires that the project planning process should allow time for the borrower and users to participate in, or preferably drive, the planning process, and for any potential losers to have a substantive influence on decisions that affect their future. Ownership and commitment by the users are unlikely to be achieved unless they consider that the project would meet their felt needs⁽¹²⁾ and they have a stake in the equity - that is, they share in or bear all of the investment costs. 

Building ownership and commitment through participation has often been difficult to achieve in the past. The conventional sequence of identification/preparation, carried out against tight deadlines by external planning teams, has seldom allowed time for genuine participation (which should go beyond mere consultation), either by government staff or farmers. On implementation, government irrigation engineers, for their part, have usually seen irrigation only from an engineering, rather than a farming or social, perspective. They have been reluctant to adopt participatory approaches with farmers, mainly because of a misplaced belief that farmers are unable to understand or make any contribution to technical matters, or because of concerns that participation might delay implementation or result in design changes that compromise the quality of the final product. 

Undue delays in project approval and implementation are undesirable, not least for the farmers; but taking time over stakeholders' participation in planning does not necessarily mean delay. It can often pay dividends, by preparing the implementers, ensuring smooth start-up, building farmers' commitment to change, and may ultimately lead to more rapid implementation and a more sustainable development impact. Experience has shown that the ultimate scheme design almost always benefits from involving the users in the planning process. Farmers, or at least those with some experience or knowledge of irrigation, from the poorest illiterate smallholder to the richest well-educated commercial farmer, usually have practical ideas of what works and what does not, from their detailed local knowledge of weather patterns, hydrology, soils, markets, and so on. Communities often have strong preferences regarding the nature and location of development that needs to influence planning, such as aligning a canal to avoid excavation in sacred ground. 

Participatory or consultative planning is essential in rehabilitation projects or the upgrading of traditional farmer-managed irrigation systems, to take advantage of the invaluable store of cross-disciplinary knowledge that farmers possess about the existing systems. Projects that involve the displacement and resettlement of people can only be planned and implemented effectively if those affected are involved in the planning process and their suggestions and concerns taken fully into account. 

As will be seen from Chapter 5, involving farmers in system design can also often result in significant cost savings, particularly if the farmers themselves are expected to take a share in the equity by contributing to the investment costs. Sound engineering is essential, but it can nonetheless take account of the farmers' experiences and preferences. Yet farmers, as a possible source of system design input, are still too often ignored by engineers, and as a result schemes are often inappropriately planned (see Box I-4). 

A Possible Role for Non-Governmental Organizations (NGOs)⁽¹³⁾ in Participatory Development

Farmers may be as uninterested in participation as government irrigation bureaucracies, especially if in the past they have received free, though possibly unreliable, irrigation services and are now expected to bear more of the costs. They may often be suspicious of government officials, especially if they have been the losers as a result of incompetent or corrupt practices. Farmers may therefore require considerable persuasion to commit themselves to participate. 

Participation usually also requires behavioural change in irrigation bureaucracies, and until this is achieved they may not be in a position to implement participatory development. Some bureaucracies have successfully employed young graduates in social science to work directly with farmers to assist the latter to mobilize and organize themselves to participate in project planning and construction⁽¹³⁾. However, for various reasons it is often difficult for irrigation bureaucracies to attract and retain such staff. Even if such staff can be recruited, farmers may still hesitate to cooperate fully with persons they regard as government agents. In this case what is often required is a non-governmental intermediary, to identify community needs and articulate them on behalf of the otherwise voiceless. While non-governmental organizations vary in their ability to work with the poor and to cooperate with government agencies, several of them have undertaken this role successfully. 

However, caution is necessary to avoid any suggestion that NGOs should replace more formal local institutions: in some cases, there would be advantages but in others such a move could be counter-productive. Instead, suitably qualified and motivated NGOs may be sub-contracted, either by local government⁽¹⁴⁾ or through the farmers' own administrative structures⁽¹⁵⁾, to provide technical assistance services to animate participation. They may also often assist in capacity building by training government staff in this role. 

5. FISCAL SUSTAINABILITY 

Economic efficiency and fiscal sustainability demand that the capital costs of irrigation infrastructure should eventually be recovered from the users, in order to permit longer-term replication of investments. On equity grounds, it can also be argued that costs should be recovered, as farmers who are able to irrigate tend to be amongst the better off members of the rural population. In practice few countries have ever succeeded in recovering much more than the O&M costs of public irrigation directly, although indirect recoveries in the form of agricultural taxes or generally negative terms of trade for the subsector have in some cases been important (see Box I-5). 

It has also been argued that the complexity of some irrigation and drainage schemes justifies state intervention and subsidizing of part of the investment costs, without which some worthwhile projects may not have been constructed. In these cases capital costs not recovered may not really be subsidies if all the secondary benefits of irrigation development are taken into account. In a case study of the Muda Irrigation Project in Malaysia, for example, it was found that for every dollar of value added generated directly by the project, another 80 cents were generated downstream⁽¹⁶⁾. Moreover, other researchers have argued that the multiplier effects of investment in agriculture in developing countries are generally greater than those associated with investment in other sectors⁽¹⁷⁾. Nevertheless, the governments of many developing countries faced fiscal crises during the 1980s that focused their attention on the shortcomings of existing policies for financing irrigation, particularly with regard to the O&M costs. The general consensus now, among governments and financing institutions, is that users should pay all of the O&M costs and as much as possible of the capital costs. 

Problems with cost recovery and O&M form a vicious circle. Irrigators on public schemes are commonly reluctant to pay any charges that they are not forced to: poor collections lead to poor O&M, and an even greater reluctance to pay. It is also generally accepted that the standard tactic for dealing with poor O&M in the past - that of relying only on raising water charges - does not usually work, mainly because revenue from water charges (if they are collected) is often returned to the general treasury instead of being allocated to O&M. There are exceptions to this rule, for example on public schemes in Morocco, but in these cases increased water charges have been accompanied by improved service, hence greater willingness to pay on the part of the farmer. 

Any suggestion that irrigators on a public irrigation scheme cannot afford to pay even the O&M costs needs to be examined very critically. If irrigators cannot pay it can only be assumed that the scheme is either unviable - in which case the question should be asked why it was built or what can be done to make it viable - or unreliable, in which case measures should be taken to correct the situation. Moreover, there is an issue of equity involved in subsidizing some members of society by way of artificially cheap irrigation: in principle it may be a praiseworthy social objective, but with typically high unit costs for irrigation development, the social impact would in most cases be greater if any subsidy was spread more thinly over a higher proportion of the rural poor. Fiscal constraints in many developing countries simply do not permit subsidies of this kind anyway. 

The application and collection of water charges can be further complicated by various factors, including for example local customary law, or a fundamental belief in some countries that water should be free. There is also the difficulty of volumetric measurement. The first of these may be overcome to a certain extent by charging a "service" fee for irrigation. But this usually takes the form of an area or crop-based fee that provides no incentive for the efficient use of water and may thus contribute to wasteful usage. Even if it were possible to charge individual farmers for water on a volumetric basis, which it seldom is for most surface irrigation systems involving smallholders, setting an appropriate charge may present some difficulty because of local economic distortions (see Box I-5 above). Nevertheless, without some form of volumetric charging, individual irrigators have little incentive to make more efficient use of water. 

One solution to the problem of water charges is to devolve financial autonomy for O&M to users' groups, or to irrigation agencies dependent upon the users for finance. Metering of water supplied to larger groups, even if only approximate, is usually more technically feasible, and the group as a whole can then be charged. It becomes the group's responsibility to allocate water amongst its members and to recover the charges; the experience is that users' groups are more effective collectors of fees than government agencies. However, this solution will depend for success entirely on the cohesion of the group involved. Conditions for the sustainability of users' groups are discussed later. 

Apart from the obvious fiscal advantage, a contribution by users towards the capital cost of a new or rehabilitated scheme is an indication of demand and commitment. In effect, this is an investment in equity and hence the scheme becomes to some extent private, enhancing prospects for sustainability. For this to happen it requires that the users will be in a position to make such a contribution, and that there are no economic distortions in place that make it impossible for them to do so. 

It also presupposes that government is committed to recovering costs. Yet there are many examples around the developing world where governments and donors have adopted the view that users are too poor to make any capital contribution. In these cases the construction or rehabilitation of an irrigation scheme is often seen as a welfare project rather than as an investment project, and farmers are paid in cash or food to contribute labour to the construction of the scheme. There are no signs that such an approach engenders any sense of ownership or responsibility. Farmers are more likely to view construction simply as a source of off-farm employment, to regard the scheme as government infrastructure and ultimately to show little subsequent commitment to it. Moreover, the injection of large amounts of food into an area under food-for-work programmes can sometimes depress agricultural prices and affect other farmers' incomes. 

Even among very poor populations, individuals and communities have been willing and able to invest substantial amounts in cash and kind for projects that they consider are worthwhile. If nothing else, irrigators or prospective irrigators can contribute labour, even if only for a few hours a day, and provide locally available materials for construction. Unwillingness to contribute implies a lack of demand for the irrigation development proposed, hence a lack of commitment, which invariably leads to unwillingness to accept O&M costs. Thus the International Fund for Agricultural Development’s (IFAD) irrigation and drainage investment strategy⁽¹⁸⁾ requires that users should "contribute between 10-20 percent to the direct costs, preferably in kind or labour", and that they should "pay for the cost of irrigation equipment (cash/loans)". Experience suggests that this is not unreasonable, if the development proposed is an appropriate response to local demand for irrigation⁽¹⁹⁾. On some public systems in Morocco, for example, up to 40 percent of the initial capital costs are recovered from farmers, and private irrigators throughout the world - including those on traditional farmer-managed irrigation schemes - are willing to pay up to 100 percent of the cost of their schemes. 

As mentioned, case studies have shown that requiring a capital cost contribution from farmers can result in significant overall savings if farmers themselves are involved in system design. For example, in the IFAD/World Bank-funded Communal Irrigation Development Project in the Philippines, actual costs were US$ 4,100 per hectare compared with the originally estimated US$ 7,000, not only because of the farmers' contribution of labour and materials, but also because of farmer-led design changes⁽²⁰⁾. Farmers will invariably seek the least cost solutions if they have to pay even a part of the costs. 

Land tenure problems can, however, be a constraint to users' participation in capital costs. Where farmers are unable to gain legal or even customary title to their land they are not normally willing to invest, unless they have confidence in long term usufructuary rights. Legislation may therefore be necessary in order that freehold tenure or long leases can be granted - for which reason, among others, government commitment to the proposed investment is essential. 

Fiscal crises have in many cases forced governments to devolve financial and managerial responsibility for existing irrigation systems to the users - in effect to privatize them - and to ensure that users' groups on new schemes accept full responsibility for O&M from the outset. 

The degree of responsibility which water users' associations (WUAs) can be given for management of a system depends on its scale. It is obviously unrealistic to expect a WUA to take over full responsibility for a system that serves hundreds of thousands of hectares and which was previously operated (even if poorly) by a large irrigation agency. On the other hand there are other options available, such as users' representation, either directly or indirectly through apex WUA organizations, on the board of a financially autonomous irrigation authority, or for WUAs or their apex organizations to make a contract for the provision of irrigation services with the private sector. Smaller schemes, including their main water supply infrastructure, might on the other hand be managed entirely by a WUA. The objective in either case is greater user commitment, which can lead to more efficient use of the resources by helping to overcome many of the problems that public irrigation systems face, such as inequitable water distribution, corruption (see Box I-6), inefficiency and poor O&M. Attention is nowadays being focused on how to achieve this commitment, and to what extent WUAs can be assisted to form and to manage their own affairs. 

Experience to date in the formation of WUAs and the transfer of irrigation O&M responsibilities to them has been uneven. The 1994 World Bank review of its experience in irrigation, referred to earlier, concluded that some WUAs have been stillborn, some have died in infancy, and some have lived on but performed no useful function. Byrnes⁽²¹⁾ concluded that most WUAs in World Bank-assisted projects in Pakistan remain relatively weak. Meinzen-Dick et al.,⁽²²⁾ reached a number of conclusions regarding what leads to strong WUAs, the policy factors that can assist in the development of such organizations, and the implications for constructive interaction between irrigation agencies and WUAs, particularly for the transfer of irrigation responsibilities.

These were summarized as follows:

• WUAs are stronger if they can build upon existing "social capital", or patterns of cooperation. It is therefore advantageous to work with existing successful organizations wherever possible. Whether existing or new organizations are involved in irrigation management, the organizations should be adaptable - to their local conditions and to changes over time. WUAs are also likely to be stronger if they are relatively homogenous in terms of members' background, and assets. However, heterogeneity is manageable (or even, in some instances, desirable), and defining membership to include all stakeholders - including tenants and women - improves equity.

• There is no single "optimal size" for WUAs. As size increases, transaction costs increase and it becomes more difficult for members to monitor each other. However, larger WUAs can achieve economies of scale, and take on more tasks in irrigation management. Federation allows WUAs to expand and operate on a larger scale, while still maintaining manageable interactions among members of base-level groups. 

• The structure and role of WUAs depend on their degree of commercialization. Greater commercialization allows WUAs to replace direct labour or in-kind participation of members by hiring specialists, and allows them to expand in size. However, it also creates a much greater need for accountability of leaders and employees to the membership. 

• The range of WUAs shows great variability, but two broad models can be identified. The first (or "Asian model") typically relies on direct participation of all members, with smaller base units. These are often socially based, multipurpose organizations and are likely to be most appropriate in socially cohesive societies with smaller land holdings, low market penetration and simpler irrigation technology. The second (or "American model") is a more specialized organization based on hydraulic boundaries, and the organizations are focused on irrigation rather than multiple activities. Such organizations are appropriate to situations of larger land holdings, greater market development, and more complex technology.

• In any type of WUA, the benefits to farmers should outweigh the cost of membership. The benefits of improved water supply, increased farm income, and conflict resolution obtained through WUAs should offset the substantial time, materials, cash, and interpersonal transaction costs of being involved in the WUA. This implies that irrigated agriculture should be profitable enough to create a demand for water, and WUAs should have a demonstrable effect in improving farmers' control over water. 

• Organized farmers in WUAs can manage more advanced technology, and higher levels of irrigation systems. Their expanded role in main system management can provide a greater degree of control over water supplies, which, where water is scarce, is a major incentive for farmers to participate in WUAs.

• Where public agencies retain operation and maintenance responsibilities at higher levels of the system, they need to carry out these roles effectively so that farmers will feel it is worthwhile for WUAs to carry out their functions at lower levels. Developing a service orientation among agency staff and a collaborative attitude between agencies and WUAs is essential for successful joint management of irrigation systems and for management transfer programs. Strengthening agency accountability to users through public information of irrigation plans and programmes and providing financial autonomy for irrigation agencies to rely on user fees for their budgets are strong incentives for the agency to foster WUAs. 

• A supportive policy and legal environment is crucial to the sustainability of WUAs. State policies of administrative and financial decentralization have provided the impetus for many management transfer programmes which diminish the role of the state and expand the role of WUAs. A facilitating legal framework is critical to give WUAs the ability to deal effectively with external groups, operate bank accounts and undertake other activities. However, the legal framework should be flexible enough to allow members to adapt their organizations to local circumstances. It should also balance rights with responsibilities for WUAs in order to ensure that members have sufficient incentive to participate. Clear assignment of property rights over water and over the physical infrastructure of irrigation systems to WUAs can be a potent tool for strengthening the organizations, and should be given greater attention, particularly in programs which aim to transfer responsibilities and costs of irrigation system management from the state to users. 

• There is a changed but essential continuing role for the state in ensuring long-run sustainability of WUAs. Particularly important roles for the state are establishing and adjudicating water rights, monitoring and regulating externalities and third party effects of irrigation, maintaining a supportive legal framework, providing technical and organizational training and support to WUAs, and occasionally providing design, construction, or financial support for major rehabilitation. 

However, turning over management of public irrigation schemes is not merely a matter of consultation and forming WUAs, with government continuing to act as the prime mover. Power struggles, collusion and corruption may not always be eliminated by user participation and the creation of WUAs. Not too much should be expected from them, especially in the short term. Their creation requires a re-orientation of irrigation bureaucracies towards providing a service and creating an environment that facilitates the formation, by the users themselves, of sustainable WUAs. Sound social engineering is as necessary as good technical engineering. The ease with which sustainable WUAs will form, and successful transfer of responsibilities will then take place, will vary according to different physical, social and financial circumstances. There is no magic solution, no one set of rules can be applied, and considerable time and resources will have to be invested in learning how best to approach the process in each case. Investment project designs which provide flexibility and a progressive or pilot-led approach to transfer are more likely to lead to eventual success⁽²³⁾.

7. SOCIAL AND ENVIRONMENTAL ASPECTS 

Adverse social and environmental impacts of irrigation investments have been many and varied. They include health impacts (malaria and schistosomiasis), and waterlogging and induced salinization⁽²⁴⁾. Displacement of people from dam sites with inadequate consultation and compensation has also been a major source of problems. Land acquisition and resettlement requirements have often caused delays to implementation or even cancellation of loan agreements. Although some would argue that on the whole the social and environmental disbenefits of irrigation are far outweighed by the benefits, there are a number of irrigation projects around the world that possibly would not have been built had the full negative effects been foreseen, costed and entered into a cost benefit analysis. 

Despite the years of experience and the lessons learned - and despite the existence of clear operational guidelines for dealing with social and environmental issues - governments, financing institutions, project planners and implementers have in the past often paid only lip service to the need for systematic problem identification, assessment and mitigation. In the past one of the reasons for this was that promoters and implementers of irrigation projects found that addressing such issues was an inconvenience, as well as a likely source of project delays or cancellations. And even though environmental legislation existed, environmental agencies generally did not have the teeth to implement regulations; if planners wished to strengthen these agencies in parallel with the formulation of irrigation investment proposals, it was already too late. 

The approaches and attitudes of governments and financial institutions have changed more recently. The consensus now is that social and environmental impact assessment is essential and as important as economic analysis in influencing the design of projects. 

8. CHOICE OF TECHNOLOGY 

Common sense dictates that the choice of technology for irrigation should be based on its appropriateness for the cropping patterns intended and should also consider cost-effectiveness. Irrigation engineers have in the past tended to overlook an additional need: for the technology also to be matched to the level of sophistication or operational capacity of the users. It has become increasingly obvious that the design process must start from a consideration of how the users will operate the system; this should then be designed to provide the optimum combination of efficiency in water use and cost effective operation and maintenance. Equally important, the designer must consider how the user will cultivate his land, and the implications that this may have for scheme layout. Thus it may be that the design which involves the lowest investment cost per hectare may not be the most cost effective solution if it also involves large numbers of staff for its operation, or if, because of operational difficulty, it cannot be utilized to capacity. On the other hand, a design to improve water use efficiency on a traditional irrigation system by the introduction of "modern" water control structures may not result in overall efficiency gains if the users reject the modern controls in favour of their traditional proportional dividers. 

The choice of technology, whether for new development or rehabilitation of existing schemes, has been the subject of much debate over the years. While most irrigation engineers would now agree that the starting point for design must be ease of operation, they still tend to polarize into two camps. One sees the problem largely as overcoming the hydraulic instability of extensively-gated manually operated systems; it sees the solution as the modernization of these systems, adding automatic downstream control structures and other feedback mechanisms designed to achieve hydraulic stability. The other accepts the reality of farmer damage in wet season drought and so favours designs based on cruder and more robust structures; the possibility of just-on-time, demand-based, delivery of water to crops is foregone, in the hope of preserving the civil works from interference⁽²⁵⁾. 

Discussion of this issue is well covered elsewhere⁽²⁶⁾ and need not be continued here except to note the conclusion of the World Bank in its 1994 review of its experience in irrigation, that there is inconclusive evidence to favour one camp or the other. Both would agree on the need to eliminate anarchy and on the importance of flexibility of operation. 

9. THE DRAINAGE DILEMMA 

The world is faced with a huge backlog in drainage requirements. Over the last quarter of a century water usage for irrigation has more or less doubled without a comparable increase in drainage capacity. In the longer run poor drainage is one of the most significant causes of reduced yields and of irrigated land going out of production, as shown, for instance, by the extent of saline and waterlogged areas in Pakistan. The stage has now been reached when it is necessary to correct the drainage omissions of the past. At the same time there is a need to improve water use efficiency to reduce the drainage demands of the future. 

It is necessary however to consider why, even where provision for drainage has been made in the past, it has often survived for only the first few years of a project's life. In most cases of poor scheme maintenance it is the drains that are allowed to deteriorate first. One of the main reasons is that within a year or two of construction tertiary drains are often cultivated over by the irrigators who are theoretically responsible for them. Secondary drains, which are usually the responsibility of the irrigation agency, are often also partially filled in by farmers to provide crossings or to pond water for other purposes. The main drains are therefore quickly rendered redundant. 

To improve the sustainability of drainage systems, channels should be limited to those which are essential; but these should be adequately maintained and defended against encroachment. Provision of crossings, each with adequate culvert capacity, is essential or obstruction by informal cultivator-constructed crossings will inevitably result⁽²⁷⁾. The challenge is to persuade farmers to accept the importance of drainage and to take responsibility for its maintenance. This further reinforces the need to promote participation and ownership by the users. 

10. IMPLICATIONS FOR THE PLANNING PROCESS 

To summarize, there is growing recognition that: 

• Water is a scarce and valuable finite resource with many competing demands for its use. Where such competing demands exist, charges for irrigation use should at least reflect its scarcity value. International funding is unlikely to be made available for irrigation if the use of water for this purpose prejudices other more profitable uses. 

• There are more important issues in irrigation than that of scale - for example the degree of users' demand and commitment to subsequent O&M. The issue of scale should be approached with an open mind, in each case considering the circumstances of the country and project opportunities concerned. 

• Although world food supply will depend even more on irrigation in the next century than it has in the past, the per hectare capital costs of typical new irrigation development may be difficult to justify by the returns from basic food crops alone. Unless low cost solutions can be found, or demand forces the price of basic food crops up, irrigation investment to achieve incremental food production (other than rice) may be limited to upgrading existing formal and traditional irrigation systems. 

• Apart from the obvious technical and financial conditions, the key condition for sustainable development impact from an irrigation investment project is its implementability. This requires that the institutional demands of the project are matched to local institutional capacity, and that stakeholders are genuinely committed to the project through participation and local ownership. The conventional project identification/preparation approach of the past, which has left little room to participative approaches to project design, has militated against these requirements being met. 

• Economic efficiency and fiscal sustainability demand that the O&M costs and at least a part of the capital costs of irrigation should be recovered from the users. However, in practice this is rarely achieved. Fiscal crises in many developing countries are now forcing governments to devolve responsibility for existing schemes to the users or private companies, and to ensure that users of new schemes accept responsibility for O&M from the outset. This often requires institutional reorientation of irrigation bureaucracies, the formation of users' groups or WUAs, and an even greater need for participation and local ownership. 

• Adverse social and environmental impacts are significant contributors to project failures. Despite past mistakes, governments, financing institutions, planners and implementers all too often continue to pay only lip service to the need for impact assessment and to internalizing the findings in project design. The consensus now is that social and environmental impact assessment is as essential and important a tool as economic analysis in planning successful projects and programmes.

• Drainage should be given much more prominence than in the past, in both strategy formulation and the planning of individual projects. 

• The implications of these lessons for the planning process are that: 

• Project planning needs to center more on the users, and less on the requirements of the lender, and to emphasize participation and capacity-building features. Whilst project planning has always been a government responsibility, there needs to be even greater insistence that international project planning teams, such as those provided by the Investment Centre, facilitate and assist in the planning process by complementing and supporting local preparation groups, rather than assume direct responsibility for the tasks involved. Increasingly, therefore, external technical support should involve providing inputs and support to a process that is driven nationally and involves contributions from many, diverse local stakeholders. 

• Given this diversity of contributors, the planning process will continue to evolve away from conventional identification and preparation to one that is less compartmentalized. Analysis and reporting are more likely to build up a dossier of reports, working papers and other documentation, that may not necessarily be neatly a wrapped and packaged document that can be presented as an "identification" or "preparation" report. 

• Instead of producing comprehensive stand-alone preparation reports, international project planning teams will be required to produce working papers that can be used to support a project proposal or appraisal, or they may simply be required to review such papers produced by national preparation groups.

• Due to the importance now attached to social and environmental impacts the evaluation of these must be given as much prominence as economic evaluation in influencing project design.

• In some cases the planning process may become as important an end as the ultimate project plan, since it will be the main means of building local commitment and capacity. When successfully executed, this approach should be exploited to reduce the time spent in bringing about readiness for implementation, and to ensure smooth start-up, rapid implementation and ultimately sustainable development impact from investments. 

• Given the importance now paid to increasing implementation capacity, multilateral lending for irrigation and drainage is likely to continue to favour sectoral loans for this purpose, most often linked to upgrading of schemes and facilitating greater involvement of irrigators themselves, NGOs and the private sector in project implementation. Long-term technical assistance will be financed only as a last resort, with specialized short-term inputs that will focus particularly on institutional, environmental, social or organizational issues. 

[Editor’s Note: This publication is planned for revision in the near future. For an update on the World Bank’s current perspective on some of the issues raised above, the Investment Centre suggests readers look at these recent references: 

Footnotes

1. The background to this is described, for example, in the World Bank Policy Paper Water Resources Management, World Bank, Washington DC (1993) and in Land and Water Bulletin 3 Water Sector Policy Review and Strategy Formulation: A General Framework (prepared jointly by the World Bank, UNDP and FAO), FAO, Rome (1995).

2. See for example: Land and Water Bulletin 3, Water Sector Policy Review and Strategy Formulation: A General Framework (prepared jointly by the World Bank, UNDP and FAO), FAO, Rome (1995); Water Report 6 Methodology for Water Policy Review and Reform (Proceedings of the Expert Consultation on Water Policy and Reform - Rome, January 1995), FAO, Rome (1995); Irrigation and Drainage Paper 52 Reforming Water Resources Policy: A Guide to Methods, Processes and Practices, FAO, Rome (1995).

3. Rice schemes nevertheless require adequate surface drainage, as total inundation of the crop leads to significant yield losses.

4. e.g. drip or micro-jet.

5. Report No 13676: A Review of World Bank Experience in Irrigation. Operations and Evaluation Department, World Bank, Washington DC (1994).

6. The term stakeholders includes all individuals who may be positively or adversely affected by the project: government planning agencies (planning units, senior decision-makers, Ministers); government implementing and operating agencies (senior and middle level management of line ministries) who may be subsequently responsible for project implementation, operation and management; community-based organisations, including water users' associations (WUAs) or other farmers' organisations; individual farmers; public interest groups; non-governmental organisations; (NGOs) and private sector companies; financing institutions; and international project planning teams such as those provided by the Investment Centre.

7. See Soils Bulletin 57: Soil and Water Conservation in Semi Arid Areas, Land and Water Division, FAO, Rome (1987); Investment Centre Technical Paper 10: Agricultural Investment to Promote Improved Capture and Use of Rainfall in Dryland Farming, FAO, Rome (1995); also Technical Paper 221: Conserving Soil Moisture and Fertility in the Warm Seasonally Dry Tropics, World Bank, Washington DC (1993).

8. Paradoxically perhaps, the expansion of irrigation over the last 50 years has been a major factor in the decline in prices, since it has caused relatively strong growth in supply of rice and wheat compared with growth in demand.

9. Investment Centre Technical Paper 5, Irrigation in Africa South of the Sahara, FAO, Rome (1986).

10. Doubts over the use of World Bank price forecasts for food and fibre crops have often been expressed. However, in the absence of any better alternatives, the analyst can do no more than attempt best guesses based on the Bank's forecasts, or explore possible future differences between forecast and actual prices through sensitivity analysis.

11. There are exceptions to this rule: one such system has been satisfactorily demonstrated for the irrigation of cassava in some Sahelian countries.

12. This is the basis of genuine demand-driven development. Soliciting or orchestrating requests from farmers for government investments in irrigation is not - even if the prospective users promise or agree to make a contribution at some later date. Often farmers are driven by other motives in these circumstances, such as temporary wage employment on scheme construction, and they later lose interest in the irrigation scheme.

13. For example, the National Irrigation Administration in the Philippines. See An Evaluation of NIA's Participatory Communal Programme, Public Intervention in Farmer-Managed Irrigation Systems, IIMI, Colombo (1987).

14. e.g. village or district councils.

15. e.g. water users' associations.

16. Bell, Clive, Peter Hazell and Roger Slade, Project Evaluation in Regional Perspective. Johns Hopkins University Press (1982).

17. See Vollrath T.L., The Role of Agriculture and its Prerequisites in Economic Development: A Vision for Foreign Development Assistance. In: Food Policy 1994 19 (5) 469-478.

18. Drawn from Irrigation and Drainage Cluster - Module: The Role of Water User’s Associations, IFAD, Rome (Draft 20/10/94).

19. Evaluation of the Special Programme for African Countries Affected by Drought and Desertification: Thematic Study on Small-Scale Irrigation and Water Control Activities (Main Report No. 98/073 IFAD-SSA), IFAD 1998

20. From An Evaluation of NIA’s Participatory Communal Programme : Public Intervention in Farmer-Managed Irrigation Irrigation Systems, IIMI, Colombo (1987). Other experiences from different countries are summarised in Robert Yoder and Juanita Thurston (eds), Design Issues in Farmer-Managed Irrigation Systems, IIMI, Colombo (1990).

21. Kerry J Byrnes, World Bank Technical Paper Number 173, Water Users’Associations in World Bank-Assisted Irrigation Projects in Pakistan, World Bank, Washington DC, 1992.

22. Meinzen-Dick R. et al., Sustainable Water User Associations: Lessons from a Literature Review. Paper prepared for World Bank Water Resources Seminar, 1994.

23. Practitioners are referred to Orstrom, E., Crafting Institutions - Self-Governing Irrigation Systems, ICS Press, San Francisco, California (1992) which covers some practical planning principles which can be applied in most cases. Also Yoder, R., Locally Managed Irrigation Systems - Essential Tasks for Assistance, Management Transfer and Turnover Programmes, IIMI, Colombo, Sri Lanka (1994).

24. According to the 1990 FAO report An International Action Programme for Water and Sustainable Agricultural Development: A Strategy for the Implementation of the Mar del Plata Action Plan of the 1990s, 20 to 30 million hectares (or about 10 percent of the world's irrigation) is severely affected by salinity and an additional 60-80 million hectares are affected to some extent.

25. Burns R., Irrigated Rice Culture in Monsoon Asia: The Search for an Effective Water Control Technology, World Development XXI, (May 1993), pp771-789.

26. e.g. in World Bank Technical Paper 246, Modern Water Control in Irrigation(1994) by Plusqullec et al., World Bank Technical Paper 256, Design and Operation of Smallholder Irrigation in South Asia (1995) by Donald Campbell, and numerous IIMI publications.

27. Campbell D., Design and Operation of Smallholder Irrigation in South Asia, World Bank Technical Paper 256, World Bank, Washington DC (1995).