Chapter 2: Case studies

Agricultural Water Management, 22 (1992) 15-49 © 1992 Elsevier Science Publishers B.V. All fights reserved. 0378-3774/92/$05.00

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Chapter 2

Case studies

SELECTING CASE STUDIES

In the following case studies we review performance of canal delivery systems in many project areas and pinpoint the reasons for high or low performance. The common features of the case studies then form the basis of the gen- eralized theory presented in this book. For this reason the case studies are placed early in the book (and not at the end, as is often done) so as to ensure that the reader is fully aware of the conditions prevailing in many typical project cases.

Project evaluation includes both economic and performance analysis and takes into account the original project targets which are a measure of the ex- pectations considered feasible at the planning stage. Performance relates to these predictions. Economic analysis, on the other hand, is more limited in its scope and is generally confined to determining the economic rate of return (or profitability to the whole society or economy) of all the resources com- mitted to the project, regardless of who contributes or who benefits (Gittin- ger, 1982). In assessing project performance four interrelated development criteria should be evaluated: (i) productivity of water, measured in terms of efficiency and agricultural production; (ii) quality of services, reflected in the predictability, adequacy and timing of the water deliveries; (iii) socio-economic impact of maximizing farmers' net returns and minimizing inequities in distribution; and (iv) environmental impact, as expressed by long-term environmental effects. These criteria will be discussed in detail in Chapter 7.

The case studies reviewed here concentrate on evaluating three principal aspects of these critera: efficiency of delivery of the water supplied to the farmer; equity of delivery to upstream, midstream and tail-end sections of a project; and timely delivery in relation to crop requirements and farmers' agricultural programs. These criteria can be expressed simply:

- How much water was wasted unnecessarily? - Did all farmers have an equal opportunity to receive a fair share of the water? - Were the supplies delivered when the farmers needed them?

The case studies have been selected bearing in mind the following points:

16 LESLIE SHANAN

- The problems raised give prominence to aspects which have significance not only on a local scale.

- The projects illustrate how poor system management is detrimental to both efficient water use and equitable water distribution.

- Although not perfect examples of the issues raised, they describe the constraints that limit the achievement of high project performance.

The projects are drawn from a wide range of climatic conditions, such as the monsoon regions of South East Asia and the semi-arid zones of Sudan, Mexico and the State of Rajasthan in India. Of the 245 million ha irrigated in the world, approximately 43% ( 110 million ha) are situated in the developing countries (excluding mainland China, with its 75 million ha). The case studies are taken from seven developing countries (Pakistan, India, Mexico, Sudan, Philippines, Taiwan and Thailand) which together constitute approximately two thirds of the irrigated area in the developing world (excluding China). The irrigated areas in the seven selected countries range from 500,000 ha in Taiwan to 35 million ha in India, and form an important part of their national development programs. The case studies describe problems occurring in more than 30 specific project areas of sizes ranging from 3500 ha to 500,000 ha. The case studies from some of the projects also describe, in greater detail, the lessons learned from water management study areas 300-400 ha in size and water management demonstration areas as large as 30,000 ha. The examples generally highlight the theme that in evaluating the benefits of a project, one must consider the location of a particular farmer in the system and distinguish between farmers who are situated at the upstream section of the network and those who are at the tail-end. In all the case studies, the engineering facilities were technically well planned, i.e., their dimensions and structural features met accepted engineering design criteria.

Finally, in order to cover a wide range of managerial options, the case studies also include projects representative of both approaches in the planning dichotomy of 'flexible' and 'non-flexible' systems. The case studies strengthen the contention that in developing countries, flexible systems and fluctuating flows which aim to supply water according to the needs of individual farmers ( 'on-demand' deliveries) generally operate at much lower performance levels than systems with modified flexibility which deliver fixed flows according to predetermined variable frequency schedules.

THE A Q U E D U C T S O F ROME

As an introduction to the case studies, we will refer briefly to the ancient aqueducts that supplied water to Rome 2000 years ago. This historical review will uncover the interesting fact that many system problems of that era, taken

CASE STUDIES 17

singly or in combination, are similar to those that we still find in our modern day projects.

The first aqueduct delivering water to Rome was constructed in 312 BC and as the city increased in population, additional aqueducts were built during the next 500 years. By 226 AD, when the last aqueduct (the eleventh) was completed, approximately 5.6 m3/s were being diverted to the city in 430 kin of aqueducts. The popular conception of a Roman aqueduct is that of a water channel carded on tall arches, but in actual fact, the channels were mostly underground conduits and only 64 kin were above ground.

In about 97 AD, Sextus Julius Frontinus (35-104 AD) was appointed 'Water Commissioner' of Rome and assumed responsibility for the water supplies. He was a man of inflexible integrity, whose fine moral qualities and magnanimity had been proven previously when he fulfilled the position of the Governor of Britain. Frontinus, as a newcomer to the position of Water Commissioner, wisely decided that he must first learn all he could about the aqueducts. He published his findings in a book 'De Aquis Urbis Romae ' which contains a wealth of information on the water laws of that period and on the construction and operation of the aqueducts (Herschel, 1899; Bennet, 1925 ). But 'De Aquis' is more than just a technical record. It gives a picture of how a sincere and honest public servant motivated by strong civic virtue and con- science, reacts when he is appointed to an office that has long been a sinecure and finds that he is confronted with abuses and mismanagement of long standing. Frontinus first studied the amount of water that was diverted at the headworks of each aqueduct, and how much was lost in transit. In his book he also describes how he measured the flows. He reported that there were many leaks in the system and that delivery outlet points had often been tamp- ered with. He noted that there were significant discrepancies between the actual flows, and those recorded by the project managers. The discharge of the aqueducts far exceeded the quantities recorded in the official reports. His in- spection of the systems also brought to light the fact that large quantities of water were illegally diverted from the networks for private use. The official records completely disregarded the unauthorised diversions. Frontinus stated:

"74 ............ I have no doubt that some people will pay attention to the fact that the measurements showed that the actual discharge was much larger than those shown in the Caesar's records. These errors result from (the estimates made by) those that previously carded out flow measurements of each aqueduct. It is difficult for me to accept (that the discrepancies from the actual flows) are due to the fluctuating seasonal discharge or to the effect of a drought year. I purposefully carded out the measurements in July (during the middle of the dry summer season) when the discharge of every aqueduct remains constant during the whole summer season. Whatever may be the reason for any discrepancies in flows, one fact was deafly evident - that 10,000 quinar-

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iae were lost on the way and this at the time when the Caesar limits the allocations according to the quantities recorded for each aqueduct."

Now a quinarius, the volumetric unit of measurement of water used by the Romans is the amount of water flowing through a pipe ('quinarius') with a diameter of 'one and a quarter fingers (digitus)', equivalent to a diameter of approximately 2 cm. A 2 cm diameter orifice would deliver approximately 20 m3/day under a head of l0 cm. Ten thousand quirinrae is therefore equal to approximately 200,000 m 3 a day: a significant quantity of water in relation to the total quantity delivered by all the aqueducts which was approximately 14,000 quinariae!! This means that about 70% of the water, as measured at the headworks of the aqueducts, was lost due to leaks and illegal diversions. Even allowing for discrepancies in the measurements (Biswas, 1970), there is no doubt that Frontinus had discovered and made public the knowledge that the systems were mismanaged and poorly maintained. Frontinus continues:

"75. Discrepancies were also found between the measurements recorded for the discharge along aqueducts - a smaller flow was recorded at the settling basins than at the (upstream) headworks and a still much smaller quantity recorded at the point of supply (downstream). The reasons (for these differences) lie in the dishonesty of the water officials, because I found that they diverted water from the public canals for private use. Furthermore, a large number of estate owners, over whose lands the canals pass, made outlets in the canal sides and in this way the flow is decreased in the canal and water delivered to private farmers for irrigation."

"76 ...... No more can be said for these illegal actions, and in no better way than in the speech of Calius Rufus which was called 'Regarding the Water'. Indeed, only if we did not know that even today the same illegal actions are being perpetrated with the same immunity. I found irrigated fields, shops, top floors in houses, and even brothels - all with fountains flowing freely and continually. Accordingly, supplying water to an unauthorized person or under a false name is a simple act ..... "

Frontinus then records the discharge of each aqueduct and describes problems of organization and maintenance of the systems. He concludes with the following optimistic paragraph:

"130 .......... I will not deny that those who perpetrate acts that do not conform to these practical regulations deserve their punishment according to the law. However, it would be far better if those who have taken advantage of the official laxity of enforcing the laws that has been going on for a long time, would change their ways willingly and we have therefore endeavoured not to disclose the names of the perpetrators. Those that have been warned by us, without disclosing their names, can approach the Caesar to receive his for- giveness and they can regard us as helping them in this respect. In future how-

CASE STUDIES 19

ever, I hope that there will be no need to enforce the law, and the officials will faithfully carry out their duties - even if it will affect them personally."

A more recent historical note was recorded by Rudyard Kipling who described the inequities he found a hundred years ago in the irrigation systems in colonial India. In the short story 'William the Conqueror' he describes in his concise style and with empathy, the 'shop' talk of the young adminstrators who always discussed the "canals and the policing of canals; the sins of the villagers who stole more water than they had paid for, and the grosser sin of the native constables who connived at the thefts". As we shall see later in this chapter, little has changed in many areas in India and Pakistan during the century.

PAKISTAN

Pakistan, with 15 million irrigated hectares, contains the largest intercon- nected irrigation system in the world. The system comprises the Indus River and its major tributaries, three major storage dams, 19 barrage headworks, 43 major canals and approximately 90,000 village systems. The canal systems and the methods of water delivery were originally planned to divert water from the unregulated rivers and subsequently adapted to meet the requirements of the 1960 Pakistan-India Indus Water Treaty. The construction of the Tarbela and Mangla dams made possible the integrated development of the entire Indus Basin. The systems were planned to bring to maturity the largest possible cropped area with the minimum consumption of water per unit of area. Consequently, irrigation intensities are low: 25% in the wet rainy ('kharif') summer season and 50% in the dry ('rabi') winter season. Overall irrigation efficiencies are low, probably less than 30%. Natural and artificial drainage is inadequate and over-irrigation, combined with excessive leakage from canals, has led to a rise of the water table on a regional scale. Wateflog- ging conditions have developed in more than 50% of the irrigated area and the expanding salinity hazard has motivated the government to carry out a series of extensive projects for salinity control. Approximately 40% of the present irrigation budget is allocated for implementing these control and regulation measures. Understandably, in a system of this size (with 56,000 km of canals and 1.6 million km of watercourses and farm channels), a wide range of operational problems exists. During the last 40 years the government has investigated and studied many of the problems and issues. We will refer first to the studies reported by the Colorado State University (USA), which carried out extensive field work in a number of zones in Pakistan (Lowdermilk et al., 1978 ). Social structure, local customs and traditions, and farmer par- ticipation, formed important aspects of their studies. The results of their work in the Punjab and Sind zones show that distribution network problems were a major constraint on production, and, they concluded inter alia the following:

20 LESLIE SHANAN

- A major loss of water occurs in the sections of the network located between the turnout from the main canal and the inlet to the farmer's field, ranging from 33% to 65%, and the losses average approximately 25% per 300 m of watercourse, i.e., in the ditch leading from the government outlet to the farm inlet.

- Field application efficiency (the proportion of the water entering the farmer's field and stored in the root zone) was highest for tail-end farmers, where water was scarce.

- Yields of wheat, rice and cotton were a function of the reliability of water supplies; cropping intensity decreased according to the distance of the farmer from the head of thewatercourse.

- Most of the farmers (70%) were never informed in advance of the closing of the canals for maintenance work.

- The majority of farmers (73%) declared that the major constraint on production was the insufficient water supply; middle and tail-end farmers considered the water delivery constraints as crucial, about twice as often as did head farmers.

- Project management (i.e., the government) is unable to enforce its operating rules, particularly in respect to water allocations, watercourse maintenance, water stealing and bribery.

In another study in Pakistan, reported on by Bromley (1982), Donald Par- ker evaluated water delivery problems in two sections of the Punjab Province; the Khanewal Tehsil (Multar District) and the Lyallpur Tehsil (Lyallpur Dis- trict). In Khanewal, the main crops are wheat in the wet rainy winter season and cotton in the dry summer season. In Lyallpur, wheat is also the primary winter crop, but the predominant summer crop is sugar cane. An investiga- tion of farms situated at the head, middle and tail end of watercourses in the two villages showed that: (i) farm location (i.e., distance from the inlet ) along the watercourse and farm size are decisive factors determining the ability of a farmer to exert control over his water supplies; (ii) the number of farmers upstream of a particular farmer affected the water deliveries to that farmer: increasing the number of upstream farmers reduced his supplies and increased the difficulties facing a downstream farmer; and adoption of modern agricultural practices was greatly influenced by the quantity of water received, and the timely and assured delivery of these supplies.

Parker found that lack of assured timely deliveries reduces farmers' incomes and concluded (Bromley, 1982, pp. 51 ):

"... Farmers who are advantaged by size of land holding, by social status, or by watercourse location (both in terms of physical aspects of location as well as in relation to other farmers) tend to have much better water control than do other farmers. This superior water control, by boosting the yield levels of the privileged large cultivators, tends to exacerbate farm income differ-

CASE STUDIES 21

entials. Efforts to equalize water control between farmers could be a promis- ing method of improving income distribution in rural areas."

INDIA

India has the largest and most ambitious irrigation program in the world, on an area now exceeding 35 million irrigated hectares. For this reason we have included four case studies from India. Before describing the projects one should understand some of the historical developments of irrigation in this country. Most projects were built primarily to protect the farmers from fa- mines caused by recurring droughts, but during the last three decades projects have been planned also to meet the more exacting production requirements of modern agriculture. Whether the projects were defined as 'protective' or 'productive', they always were aimed at providing some protection from the long dry spells occurring during the wet monsoon period. Investment in irrigation has risen from approximately $400/ha in the early 1950s to $950/ha in the early 1980s (at constant 1970 dollars), mainly due to two factors: (i) as the easier and cheaper projects were completed, development shifted to more costly and difficult projects; and (ii) improved design and construction standards were introduced.

Projects vary in size from 'minor projects' with a command area of less than 2000 ha, to 'medium projects', ranging in size from 2000 ha to 10,000 ha, and to 'major projects', serving areas greater than 10,000 ha. The command areas of many major projects are larger than 200,000 ha and represent outstanding engineering achievements. Huge and extensive projects have understandably given rise to many problematic issues, such as: high transmission and seepage losses in the canal delivery systems; difficulties in managing efficiently the distribution network; and changes in local and regional water balances which have led to rising water tables, waterlogging and salinity. The construction of a major dam in some projects has caused the government to undertake the relocation of many village communities displaced from the res- ervoir areas.

The principal delivery systems of India can be distinguished as either 'northwestern systems' as practised in the States of Punjab, Haryana and Ut- tar Pradesh or as 'southern systems', which are characteristic of most of the rest of India. In both systems the government delivers the water to farmer service areas, 10-100 ha in size, and the farmers (5 to 100 in number) are responsible for distributing the water within this service area, locally called a 'chak'.

The northwestern systems were constructed to provide irrigation water from run-of-the-river canals primarily to protect farmers from long dry spells occurring during the wet monsoon season. These systems supply water inter-

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mittently to government outlets on rigid delivery schedules. They were designed to spread the available supplies 'thinly' over extensive areas by delivering min imum quantities of water to as large a number of farmers as possible. Irrigation intensities are low - approximately 30% to 40% in each irrigation season.

Performance of the northwestern systems is comparatively high. The management is able to operate the networks according to the agreed objectives and the projects are characterized by relatively high efficiencies, and equitable and assured deliveries. Water delivery schedules are fixed at the beginning of each season and the government implements them conscientiously. Farm- ers have introduced sophisticated cropping systems and, within the limits set by other constraints, use modern, advanced agricultural practices. Farmers are fully aware of their rights to a fair share of the assured supplies and defend these rights even if they have to use physical force against unauthorized water use. The conveyance systems are relatively simple, sections of the system are operated on a rotational intermittent basis, and outlets to farmer service areas are ungated (usually a proportional divisor which does not require adjust- ment ). Within each block, a system of rotational water supply ('warabundi") ensures that each farmer receives his fair share of the available supply in proportion to his land area. The operating rules have been in practice for gener- ations and are adhered to strictly. In many projects a farmer's allocated time has taken into account differential seepage losses in the minor network and so achieves more equitable allocations. The water available from the government supplies is not sufficient for all of a farmer's land and he is able to irrigate only approximately 30%-40% of his land-holding each season. He is free to choose his crops and the proportion of his land on which he wishes to use his water; the irrigation administration does not interfere in his decision. Many farmers have developed local ground water resources to supplement the government supplies and can thus extend their irrigated areas and diversify their cropping patterns.

On the other hand, the southern systems ('shejpali ') are typical of most of the States of India and provide an interesting contrast to the northwestern systems. First, the systems often have large storage reservoirs upstream of the main headworks to store interannual and interseasonal river flows. Second, the canal systems are designed with numerous control and regulatory structures to deliver varying rates of flows in the supply network. Third, the projects are generally planned for relatively higher intensities of irrigation - often greater than 60% per season - and include a 'localized system', where particular areas are limited to specific crops such as paddy and sugar cane. Finally, the water distribution procedures are based on allocation rules of crop sanc- tioning where the authorities approve (in theory, at least) a farmer's cropping pattern which is supposed to conform to the overall plan of the project. The project management is supposed to deliver water according to the re-

CASE STUDIES 23

quirements of the approved cropping patterns. In contrast to the northwestern systems, performance of most southern systems is low. This is reflected in low delivery efficiencies (generally less than 30%), and the total irrigated area seldom exceeds 60% of the planned target command. Most of the available supplies are controlled by the headstream farmers, who use and waste large quantities of water. Consequently, tail-end holdings suffer from insecure deliveries.

During the 1970s the Government of India introduced a diversity of innovative components into many irrigation projects to improve project pe.fform- ance. These included programs for improved organization and maintenance, canal lining, land consolidation, drainage works and watercourse contruc- tion. In many projects, rotational water supply programs below the government outlet were combined with other components. In most projects, however, inequality in water distribution and wastage of water remained central issues. Head-reach areas continued to receive more than their allocated supplies, while tail-end zones often remained unirrigated. In a series of follow-up programs, the government established several water management studies to evaluate the reasons for this poor performance and to propose improvements. The reviews given below, describe some of the studies conducted under the direction of the author in the Chambal River Project in Rajasthan and Mad- hya Pradesh, in projects in Gujarat and in the Rajasthan Canal Project. The studies were planned and organized by the World Bank for the United Na- tions Development Program (UNDP) and the field work was carded out by Government Irrigation Department staff.

CHAMBAL RIVER PROJECT, RAJASTHAN, INDIA

The Chambal Irrigation System serves areas in the States of Rajasthan and Madhya Pradesh, and an interstate agreement provides equal sharing of the Chambal River waters between the two States. The headworks for the two projects include a series of multipurpose reservoirs. The main objective of the system, initiated in 1947/48, was to provide 'protective' irrigation in the wet monsoon season for the project areas. The Main Canal was constructed to serve an area of approximately 230,000 ha situated upstream in the State of Rajasthan, and 320,000 ha downstream (see next case study) in the State of Madhya Pradesh.

The project soils in Rajasthan, mainly 'black-cotton' soils with a high clay content, swell considerably on wetting and crack on drying; they are typical of extensive areas in India. The network was designed to operate as a 'northwestern' delivery system with fluctuating flows and regulating structures. The government was responsible for delivering to the farmer service area inlets serving 25-60 ha, and below these inlets the farmers were responsible for ro-

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tating the flow among themselves. In the late 1960s, after the Government had become concerned with the extent of watedogging in the project area and with the inadequate use of the network they introduced a new package of improvements, which included drainage works, roads, land consolidation and on-farm development ( 'OFD') works, and the establishment of a Command Area Development Authority. The project also aimed to introduce rotational water supply below the government outlet so that each farmer would receive his fair allocation.

In 1978 it was found that, despite the improvements, many of the objectives of the project targets were still not being achieved. Waterlogging remained a critical problem on 25-30% of the project area, and inequity in water distribution was still characteristic of the project. Farmers adamantly refused to accept rotational water supply programs. In order to pinpoint the obstacles preventing the extension of irrigation to the entire area, a water management study was established in 1979. The study area covered approximately 400 ha. The studies uncovered conclusively the following:

- Seasonal water allocation plans were not prepared by the project management, and deliveries in the main network were dependent primarily on hydro-power demands at the main upstream reservoirs.

- Seepage and operational losses in the canal system were excessive; for example up to 45% of the flows were lost directly into the seepage drains constructed parallel to the distributaries and minors.

- Upstream farmers received more water than they required and tail-enders suffered from shortages.

- From 15% to 20% of the deliveries were wasted at night because farmers would not irrigate after dark and could control breaks in the network only during the daytime.

- From 40% to 60% of the flow in the tertiary network was lost when delivering to the last farm inlet, irrespective of whether on-farm development works had been implemented or not.

- The quantity and reliability of deliveries were functions of distance from the inlet to the farmer's fields.

- On-farm development works did not improve field irrigation efficiencies significantly.

- Delivery flows to farmer service areas (and hence to farmers) were not constant, and sometimes fluctuated from 5 to 25 1/s during the irrigation of a particular field.

Combining the findings from all the studies, it was shown that poor management and the limitations of the network prevented farmers from receiving their fair allocation. Of every 100 cubic meters delivered from a distributary, the network losses were 89 cubic meters:

CASE STUDIES 25

in the minors in the subminors' delivering to 36-ha in the watercourses delivery to 8-ha blocks Total losses

55 m 3

26 m 3 8 m 3

89 m a

The overall network efficiency from the headworks to the farmers, was therefore extremely low, probably between 10% and 15%. The studies led to the recommendation that, among other improvements, on-farm development and rotational water supply programs should be introduced into the project only after the network had been upgraded in order to ensure timely and reliable supplies to the government outlets.

CHAMBAL RIVER PROJECT, MADHYA PRADESH, INDIA

The Chambal River Project in Madhya Pradesh (World Bank, 198 lb) is a continuation of the Chambal River Main Canal in Rajasthan serving the previously described project. The project was constructed in the 1950s to irrigate approximately 320,000 ha of mainly medium-textured clay-loam soils. Farm holdings are fragmented and approximately one-third of the farms are less than 1 ha in size.

At the time of writing, not all the project area has yet been developed. An unlined distribution network serves 250,000 ha through approximately 1000 km of main, branch and distributary canals; 2100 km of lesser distributaries and minors supply to 40-ha farmer service area blocks. Two main constraints restricted the development of the project and hindered the government in its intentions to operate the project as a 'southern system', with seasonally approved cropping patterns: (i) an agreed water allocation plan could not be executed due to erratic supplies from the State of Rajasthan and a lack of sufficient regulating and measuring structures; and (ii) supplies were insufficient for the targeted area because of excessive percolation losses in the canal system.

Lack of a strong management force to implement government policies, en- couraged head-reach farmers on all distributaries and minors to take as much water as they could. Actual water delivery records are not available - an in- dication of the government's policy not to publish the planned or actual water deliveries to districts. However, the results of poor water distribution are reflected clearly in the dry season cropping patterns, because there is no effective rainfall during this season and the crops can be grown only with irrigation. These cropping patterns vary from head-reach to tail-reach throughout the project, notwithstanding relatively uniform medium-textured soils and climate.

The principal dry season crops are wheat, gram (chickpea, a pulse) and mustard. Wheat is sensitive to moisture stress and requires three to five irri-

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gations per season, while gram and mustard produce reasonable returns with a single irrigation. Farmers plant wheat when they are confident of receiving at least three irrigations, and tend to grow gram and mustard in areas where the water supply is less secure. Cropping patterns in sample reaches of the network (Table 2.1 ) bring to light the following recurrent concentration of wheat in head-reaches:

Ambah Branch Canal During the 3-year period of records ( t 975/76-1977/ 78) the average percentage of wheat was 36% at the head-reach, 28% in the middle-reach and dropped to 20% in the tail-reach. Similarly the gram-plus- mustard area was 30% in the head-reach and only 16% in the tail-reach. This pattern indicates that upstream farmers received about double the quantity of water than did the downstream farmers. On the other hand, farmers served from direct outlets on the Branch Canal (Table 2.1 ), having a more secure water supply, planted a high percentage of both wheat (32%) and gram-plus- mustard (35%).

21L Distributary on the Mau Branch Canal. In this distributary, the dispar- ity between head- and tail-reaches is even more striking. During a 5-year period (1975/76-1979/80) the average percentage of wheat in the head-reach

TABLE 2.1

Chambal River Project, Madhya Pradesh, India Dry Season Cropping Patters (in % of area)

Reach Area Length of Wheat Gram and Served Reach Mustard (ha) (km) (%) (%)

Ambah Branch Canal: (54536 ha): average for 1975/76-1977/78 Direct outlets ~ 1,720 84 32.3 34.9 Head 15,228 33 36.1 29.6 Middle 30,020 29 28.3 17.6 Tail 7,568 22 19.6 16.3

21L Distributory: ( 15515 ha): average for 1975/76-1979/80 Direct outlets 1 2,015 33 19.5 7.4 Head 3.764 9 35.7 23.7 Middle 4,439 9 12.5 21.0 Tail 5,297 15 3.7 13.8

33R Distributory: (23998 ha) in 1978/79 Head 9,065 10 31.0 14.0 Middle 9,267 7 35.0 17.4 Tail 5,666 8 16.0 18.7

~Outlets from a main or distributory canal. These sections of the network usually have a continuous (but fluctuating) delivery flow.

CASE STUDIES 2 7

was approximately 36% (similar to the Ambah Branch above). However, in the middle-reach, water constraints reduced wheat intensity to 13% and extremely uncertain downstream supplies resulted in wheat being planted in only 4% of the tail-reach. Head-reaches may have received five to ten times more water than tail-reaches.

33R Distributary on the Ambah Branch. This distributary delivers to areas in the middle-reach of the Ambah Branch Canal. A breakdown of the cropping pattern reveals the same head and tail differences occurring within the distributary as is found along the entire Branch Canal. Percentage of wheat decreased from 31% in the head-reach to 16% in the tail-reach. On the other hand, gram and mustard tended to increase in the tail-reaches as supplies became more uncertain. For more than a decade, head-reach farmers received a proportionally larger than the planned share of water along all arms of the irrigation network. These farmers regard the larger share as their acquired right and therefore object to changes.

In order to evaluate shortcomings in the network (particularly below the distributaries), studies of water management and drainage were instituted in 1979 and detailed investigations were conducted on a representative area covering approximately 300 ha. These studies showed the following: - Farmer service area efficiency (inlet to plant) averaged 33% on blocks ap-

proximately 40 ha in size while field irrigation efficiencies were relative high, 55%.

- Delivery flows to farmers varied widely from 5 to 301/s and were generally less than 10 1/s; flows fluctuated during an irrigation turn and the streams reaching the fields were sometimes even less than 5 l/s.

- Timing and reliability of supplies to a farmer were functions of the distance of his fields from the government inlet to the farmer service area.

- Low yields in many fields resulted from under-irdgation. - The watertable in some areas rose 80 cm during a single irrigation, due to

percolation, seepage and leakage from the tertiary network of watercourses and minors.

Water allocation studies carded out on a project-wide scale showed that delivery in the main canal represented a critical issue because the supplies were controlled by the State of Rajasthan, which managed the headworks to the system and the main canal. Since hydroelectric power production was given priority by the State of Rajasthan over irrigation requirements, supplies to Madhya Pradesh were erratic and unreliable. Although contingency plans had always been prepared by the State ofMadhya Pradeseh for possible variations from a seasonal plan, deliveries were far less than expected (particularly during the peak demand periods) and daily fluctuations so large, that these plans often had to be discarded. Extensive areas in the project remained unirrigated.

From the studies it was concluded that the unreliable and insecure supplies

28 LESLIE SHANAN

in the main network are the primary cause for inequity and the principal factor determining the cropping patterns of the project.

GUJARAT PROJECTS, INDIA

In 1980 the State of Gujarat (India) initiated a program to modernize existing irrigation systems and construct new projects covering approximately 210,000 ha. The projects would operate as southern systems, with cropping patterns approved seasonally by the government. One of the projects, the Panam Project, serving approximately 40,000 ha with a network fully lined down to farmer service areas of 8 ha, was chosen as suitable to demonstrate improved water management practices. The Morva Distributary (52 km downstream from the dam), serving approximately 2000 ha of black-cotton soils overlying rock at 3-10 m depth was selected as representative of the main Gujarat areas and suitable for demonstrat ion purposes. Most of the lined network in this distributary was considered to have been completed according to updated standards and was expected to be fully operable by 1981. However, the studies could not be started immediately because detailed field inspections revealed numerous shortcomings in both design and construction. Furthermore, many of the regulating gates had been removed by the farmers.

In order to establish a pilot area that could be operated satisfactorily, the size of the study area was reduced to approximately 350 ha and the delivery network in this area was rehabilitated. The rehabilitated area was called the Water Management Area (WMA) and in 1981 two village tanks were integrated into the WMA network. The main purpose of this component in the study was to answer the question "How much water is wasted by night irrigation?" The network serving the 350 ha in the WMA was brought to a management level capable of delivering predetermined flows according to weekly O N / O F F schedules but, because of the many gates involved, it took about 2 years to train the staff to operate the network and deliver constant flows to farmer service areas. A simple delivery schedule was agreed upon, with the aim of introducing rotational deliveries among farmers below service area inlets.

The main findings of the studies were as follows: - In the areas not regulated by the water management staff, flows fluctuated

widely during irrigation, by as much as 50% from the average. In the WMA on the other hand, flows to farm fields were fully controlled on an O N / O F F system, with deliveries varying less than 10% from the design discharge.

- In the WMA, dry season irrigation intensities were generally double those outside the water management area.

- Yields in the dry seasons were approximately 30% more in the WMA and production per unit of area about three times that of areas outside the WMA.

- The layout of the original project network with its numerous regulating

CASE STUDIES 29

structures required an excessive number of operators (one per 50-70 ha), at an annual cost of $10-14 per ha to ensure the delivery of the required flows. An ON/OFF operation would cut down the number of operators considerably, and annual costs could be reduced to $3-5 per ha.

- Farmers waste most night water and all farmers prefer daytime irrigation.

From the studies it was also concluded that the introduction of rotational water deliveries among farmers could be achieved only if the farmers were assured of timely deliveries according to their requirements.

RAJASTHAN CANAL PROJECT, INDIA

The Rajasthan Canal Project (now called the Indira Gandhi Nahar Proj- ect) is an ambitious plan to settle a large population on new lands in a desert zone by irrigating about 750,000 ha on the northwest system principles. The main canal, some 600 km in length, delivers water from tributaries of the Indus River system according to water allocations determined seasonally by an interstate Management Board. Construction of the project was divided into two phases, with Stage I starting in the 1950s to develop 540,000 ha. Project works initiated in 1974 concentrated on intensifying development of 200,000 ha in this area by promoting infrastructure development, on-farm works, watercourse lining, and road construction. Progress was satisfactory and there was a continuous improvement in yields, cropping intensities and production.

In 1979 the Stage II project was initiated to extend the development to an additional 200,000 ha. It was realized, however, that although the network had been designed and constructed with a system layout suitable for distributing water according to the northwest practices, many inequities had developed. The Stage II project therefore included a Water Management Zone with the object of demonstrating, on an extensive area, ways in which optimum irrigation benefits could be achieved.

In 1980 the Narangdesar Distributary at the head of the project was selected as suitable for the Water Management Zone. This distributary, approximately 40 km in length, serves an area of approximately 30,000 ha. In the first year the network was upgraded, some 180 ungated divisors were constructed, regulating structures improved, linings repaired, canals cleared of silt, and all outlet and control structures calibrated to deliver design discharges. The ungated divisors, known as Adjustable Proportional Modules (APMs) deliver constant discharge from a parent channel and are described in Chapter 7.

It was recognized that fluctuations in deliveries in the main canal affected discharges to the Narangdesar Distributary. In order to evaluate the effect of these variable flows in the past, historical cropping patterns were studied by

30 LESLIE SHANAN

stratifying the area served by the distributary into three sub-zones: head, middle and tail. The analysis showed that: (a) the number of delivery days to each zone decreased from head to tail, with head-reaches receiving 40% more flow days than tail-reaches; and (b) the decreasing availability of water was reflected in the cropping intensities, with head-reach intensities averaging 35% more than tail-reaches. A further analysis of the sub-zones showed that in each one, cropping intensities of upstream farms exceeded those in tail-end farms also by approximately 40%. In the past, tail-end farmers had received about half the quantity of water that was delivered to headstream farms, despite the fact that the entire network was lined.

In order to improve water distribution in the WMA, the following operating rules were specified and agreed upon: - Seasonal allocations to the area would be established 4 weeks before the

start of each season, depending on availability of supplies and according to the estimates of the inter-state Management Board.

- Seasonal allocations would be translated into weekly ON/OFF schedules, so that when the network was operating it would deliver at full supply level.

- O N / O F F schedules would be finalized in consultation with the Depart- ment of Agriculture, which would notify the farmers, through the Extension Service, of the programmed delivery weeks.

- The operation of the network would take into account filling and emptying times so that farmers would receive multiples of 7 days of deliveries.

- C r o s s - r e g u l a t o r s , regulating gates and flow-measuring flumes would be maintained in good working condition at all take-off points, to ensure that downstream reaches receive their equitable allocation.

- All inlets to farmer service areas would be of the ungated APM type to min- imize the size of the operating staffand also to ensure accurate delivery and minimum interference by farmers.

During 1982 and 1983 the WMA was operated successfully, first on approximately 7000 ha and then on 22,000 ha. By 1984 it had been extended to 35,000 ha - beyond its original target of 30,000 ha. The main achievements of the WMA were as follows: - Fluctuations in the flows to farmers were reduced from 50% of design flow

to an acceptable level of approximately 100/0. - Seasonal water deliveries to the farmers were reduced by approximately 15%

and made to conform to authorized project allocations; all farmers preferred the improved schedules to those that had been in operation previously.

- The operating staff required to manage the Narangdesar Distributary included one gauge reader and one ditch-rider per 2500 ha, at an annual cost of less than $1 per ha.

- Despite the reduction in seasonal water deliveries, yields and intensities increased significantly in the WMA; for example, cotton yields were approx-

CASE STUDIES 31

imately 30% higher in the managed areas than in a comparable non-managed area. At the same time, irrigated intensities were 65% in the WMA versus 47% in a non-management zone.

- Annual net returns were estimated to be $300/ha higher in the WMA than in a non-management zone.

- The operating staff quickly became adept at planning the delivery schedules and full cooperation developed among the Extension Service, the irrigation staff and the farmers.

- Predetermined schedules proved popular with all farmers in the WMA and farmers outside this area began demanding similar services.

- Equity in water deliveries was introduced into an extensive area without raising conflicts between tail-end and headstream farmers.

The WMA was a marked success due to the diligent work and cooperation of the engineers and the Extension Service. Because of its success and the demand of the farmers in other areas, the project management in 1984 began to apply the principles to an additional 40,000 ha. The methodology of delivering water according to predetermined schedules had proven simple, inex- pensive and practical, and achieved equity and high levels of return to farmers. Predetermined schedules had been criticized originally on the supposition that they might set limits to farmers' options. However, a detailed review showed that cropping patterns in the WMA vary widely from minor to minor and farm to farm. This indicated that although the predetermined schedules were inflexible during a particular season, farmers selected their cropping systems from a mix of many compatible crops. The 'fixed' schedules did not prevent them from adjusting their programs to their resource constraints (soil, capital, land, labor, equipment etc. ). They were able to remain below their preferred levels of aversion to risk and achieve high economic yields. Finally, the improved performance of the WMA area, was not achieved at the expense of the rest of the system as suggested by Chambers ( 1988, p. 62). The water delivered to the WMA conformed to the official seasonal allocation, and in no way infringed the deliveries to the rest of the project area.

M E X I C O

Mexico is situated in a global belt where the major deserts of the world are located. About 90% of the country is classified as arid and semi-add, the remainder lying in a temperate summer rainfall zone. Mexico is facing a tre- mendous challenge because of its large rate of population growth (3.6% per year) and lack of water reserves to develop its extensive arid areas. At present approximately 5 million hectares are under irrigation, mostly under the su- pervision of the Secretaria de Recursos Hidraulicos. Irrigation development began in 1926 and until 1965 projects usually lacked water control structures and a capable management. In order to improve irrigation, the 'Irrigation

32 LESLIE SHANAN

Techniques and Farm Improvement Plan' was introduced. As a result, efficiency of conveyance in the networks now ranges between 50% and 90%. Water application at the farm level has been improved and better yields in most crops have been obtained (Brondo et al., 1977). Overall project efficiency ranges from 20% to 50%. Irrigation projects vary greatly in size and are planned according to the local physiographic and hydrological conditions. Most rivers have relatively small catchment areas and their hydrology is typ- ified by torrential flows. The project described below highlights the inter-relation between water delivery flows and land ownership.

Hunt and Hunt (1978) describe the operation of an irrigation system in a small Mexican town (San Juan, State of Oaxaca) where, with irrigation, farmers can grow a wide variety of crops (vegetables, rice, mango, corn, etc. ) in an arid environment. The system is typical of rural towns in Mexico and comprises several major feeder canals and minors. The irrigated area is served by three major networks.

In the town, two feeder canals are operated. One serves the houses, or- chards, and lands around the town, while the other delivers water to the small land-owners outside the town. Irrigation is under the control of a local water commissioner who is always under pressure from powerful landlords who in- fluence the decisions on water allocations. The canals are operated by two 'water masters' who work together to discourage attack from irate irrigators. The water masters are rewarded well for the hazards of their work, and they are allowed to receive payments from the farmers so that their income is sufficient for a relatively comfortable existence. Even after having paid for his allocation, the irrigator must defend his 'rights' and stand on the ditch to ensure that the water master gives him his share. A second irrigation network comprises two privately owned canals which serve the lands of wealthy sugar farmers. There is some selling of water from the canals, but most of the supplies are delivered to the landowners for whom the system was planned. A third network serves the land of the poorest farmers.

The social organization of San Juan is characteristic of a small Mexican rural town. Of the 2500 residents, 10% belong to the elite class, 10% to the middle class, and the remaining 80% are poor. The elite own the commercial enterprises and the bulk of the land (including the irrigated areas ). The middle class derives its income mainly from service jobs in the enterprises owned by the elite, and own a little irrigated land. The poor ( 'peones') own little, and are laborers.

The Hunts, in their analysis of the social and economic organization of the township, conclude that the structure is typical of Mexico, in which land ownership - and hence water control - is in the hands of approximately 112% of the population. This same group owns the commercial enterprises in the town and together their agricultural wealth accounts for 90% of the income of the

CASE STUDIES 3 3

community. The small farmer in practice has no control over the delivery of water, especially in times of scarcity.

GEZIRA PROJECT, S U D A N

The Gezira area is a semi-arid zone of low seasonal summer rainfall in Su- dan, lying between the Blue Nile and White Nile. A major dam was constructed in 1925 to irrigate 400,000 ha of clay soils for growing cotton. Fol- lowing the independence of Sudan, the project was nationalized in 1950 and plans were initiated to expand the irrigated area to 840,000 ha. From 1960 to 1980 a program of agricultural intensification was implemented but the net result was complicated by management difficulties, deterioration of the network, the rapid spread of cotton pests, critical labor shortages and the increase of waterborne diseases (malaria and bilharzia). Nevertheless, under a central management board, the scheme became the largest irrigated 'farm' in the world. In the mid 1970s, a program of intensification and diversification was introduced and to the major cotton crop was added summer crops (mainly sorghum and groundnuts) followed by wheat.

As a result of increasing the irrigated area and extending the irrigation season, agricultural labor requirements expanded. Population density increased from two persons per hectare in 1960 to three persons in 1980. Approxi- mately 400,000-500,000 migrant laborers entered the area every year to par- ticipate in cotton picking and cultivation. The resulting labor shortages were aggravated by the spread of malaria in the mid 1970s; over 20% of the labor force was down with malaria in 1974. Increased silt and weed growth in the network became ideal snail habitats for the growth and transmission of bilharzia. In the early 1980s, surveys showed that 50-60% of the village population was affected by this debilitating disease (Abduet al., 1987).

An interesting study by Barnett (1979) highlighted the attempts by the small farmers to overcome the limitations imposed by the management of the project in operating the network. The centralized management board (Sudan Ge- zira Board) established operating rules, sanctioned the crops the farmer planted, and determined water allocations. The primary objective of the operating rules in the late 1970s was to foster growing cotton in the project area. For this purpose, water was delivered on a fixed 14-day rotation schedule. Conflicts developed between the management's objectives and the farmers' interests. The farmers preferred, for instance, to grow sorghum instead of cotton as stipulated by the management and generally ignored the government's rules. They found various ways of introducting modifications which enabled them to maximize their income but the bureaucratic management refused to recognize these innovations, which included giving a high priority to irrigation of sorghum. Since labor was a serious constraint on production at critical agricultural production stages, the farmers developed cultivation and irriga-

34 LESLIE SHANAN

tion practices that minimized labor requirements not only during daylight hours but also at night - a practice that was contrary to the original project plan (see also Chapter 7 ).

Barnett concludes that these innovations were the major factor in contrib- uting to the intensification of agricultural production in the project, even though the management refused to recognize that farmers were not following the rules. Though water is the limiting factor in production, farmers in spite of the management's plans, developed innovative practices in several important respects within this constraint. Barnett also reports that production in the project was quite good, but the top level of the bureaucracy was not informed of this, because the cropping systems did not conform to the management's objectives.

After 1980, the cotton harvest and general productivity declined dramati- cally due to a combination of factors: the failure of a program for chemical control of a major cotton pest because of decreasing cooperation between farmers and management, and worsening health and social conditions in the project area (Abduet al., 1987 ). This prompted an extensive review of the project and the introduction of rehabilitation programs for the entire project. The new program included health components, rehabilitation of the water control gates and drainage systems, and introduction of improved water management in the irrigation system.

In a recent study of the performance of the Gezira Irrigation scheme (Plus- quellec, 1990), it is apparent that most of the problems reported by Barnett (1979), still limit agricultural production. Plusquellec discusses, among other issues, the extent to which the system provides or does not provide equitable, reliable and timely water distribution to farmers, and highlights the following network problems: (a) Project inspectors, whose task it is to control the flows, rarely intervene

in the routine opening and closing of outlets. (b) The farmers, in order to be able to irrigate as large an area as possible,

leave field gate outlets open 24 hours a day, and this continuous irrigation prevails without farmers' attendance - particularly at night time.

(c) Because of the continuous irrigation practices, discharges are often well below full supply levels and deliveries are 30-50% of design discharge (approximately 116 1/s ).

(d) The original field outlet pipe gates discharging into 38 ha blocks were subject to theft and tampering and most have been replaced by drum bottoms, bags or local materials - or not replaced at all.

(e) The infestation of the canals with weeds and the deposition of silt have become the most serious problem of the project and the capacity of the canals has been seriously reduced.

Plusquellec (1990) points out that claims of inequity in water distribution

CASE STUDIES 35

are frequently being made. He also states that water delivery in some areas is neither timely nor reliable and little water reaches the tail-end farmers. Inves- tigations of present system performance revealed that the management information system is manipulated by the project staffand large discrepancies were found between the recorded water orders (indents) and actual deliveries. Further investigations also disclosed that there is little relationship between the observed values of gate openings and the values recorded by the project staff. Apparently, many of the problems reported by Barnett (1979) are not significantly different from those reported by Plusquellec (1990). Hired labor is still an imporant constraint to production - only 15% is supplied by family labor and the remainder comes from local or immigrant hired labor. Agricultural production is still disappointing. Average cropping intensity is about 60% - much lower than the 75% planned by the authorities. Yields of cotton, wheat, groundnut and sorghum are low and average about 20-30% of those achieved at research stations. The government now intends to embark on extensive weed eradication and silt clearance programs in order to improve equity and reliability in water distribution. These improvements would in turn increase agricultural production, but farmers would still have little choice in deciding which crop they can grow. Some of these project specific issues are referred to again in Chapter 7. Lessons of the Gezeira scheme include the inherent limitation of large scale irrigation projects - centralized authority and lack of response to markets.

PHILIPPINES

One of the Philippine government's major objectives for the agricultural sector has been to achieve self-sufficiency in basic foods, especially rice and corn. The National Irrigation Administration (NIA) established in 1974 was given the responsibility for developing, operating and maintaining all national irrigation systems in the Philippines. The main thrust of the NIA in expanding the irrigated areas and in rehabilitating existing projects has been directed at the large rice-growing projects, particularly in central and northern Luzon. These programs also included the provision of better drainage, the introduction of water management and irrigation practices, and augmenting water supplies by constructing storage reservoirs and transbasin diversions. Today, the irrigated area of the Philippines constitutes approximately 2 million ha, of which 80% is devoted to rice production. Until the 1980s most projects failed to achieve the expected benefits, and irrigation development began to be viewed within the context of overall rural development (Tech, 1980). The main problems of the projects included inadequate operation and maintenance of the networks, appreciable water losses in the networks, weed growth and silting in the canals. These problems were aggravated by the pe- riodic occurrence of typhoons in the area.

36 LESLIE SHANAN

The International Rice Research Institute (IRRI) at Los Banos in the Phil- ippines, became involved in evaluating operational problems in irrigation systems and conducted extensive research and field studies in the Philip- pines. We will refer here to some of the field studies carried out by Wickham and Valera (1976) in rice projects located in the Laguana, Balacas and Neuva Ecija provinces on systems ranging in size from 3600 to 75,000 ha. Their work is particularly relevant because they consider that "the results should apply to varying degrees in other countries of the region, depending on the extent to which the underlying conditions are similar".

Wickham and Valera (1976), defined two major categories of factors affecting yield and production in rice projects: those not associated with better water management; and those associated with better water management. Three factors were cited as not associated with better water management.

( 1 ) Farm ditch density. Wickham and Valera classified three levels of farm ditch density: low, less than 6.9 m/ha; medium, 6.9-15.5 m/ha; and high, greater than 15.5 m/ha. They introduced the criterion of 'stress days' - the number of days a paddy was drained of water, i.e., no surface water was recorded as standing in the field. Based on field observations, they found that the number of stress days was associated with farm ditch density and distance from the outlet. The data in Table 2.2 indicate that stress days were markedly fewer where farm ditch density was < 15.5 m/ha and the paddies farther than 150 m from their water source. They concluded that only those farms situated farther than 300 m from the water source, benefited from a greater farm ditch density. Minimum stress days were recorded for projects where farm ditch density was medium (7-15 m/ha ) and farms less than 150 m from the outlet. They also found that the number of stress days was not significently related to other physical parameters.

(2) Distance of farms from turnouts. In another study, Wickham and Val- era (1976), however, found no significant effect of the distance a paddy farm was situated from the turnout serving a 'field-to-field' irrigated block. They

TABLE 2.2

The relationship between farm ditch density and stress days ~

Farm ditch density (m/ha)

Distance from outlet (m)

Near Intermediate Far < 150 150-300 > 300

, stress days Low: < 6.9 23.7 21.7 38.2 Medium: 6.9-15.5 22.2 21.4 25.0 High: > 15.5 22.2 33.0 25.3

~Wickham and Valera (1976).

CASE STUDIES 3 7

explained that this was probably due to the high correlation in this study that existed between increasing distance and elevation. Farms at the lower eleva- tions had heavier soils with lower infiltration rates and were often closer to the water table, two factors which compensated for the increased distance.

On the other hand, they reported on a study by Tabbal in the Peneranda River Irrigation Project, who found a significant relationship between overland flow distance and number of stress days. This study indicated that in a dry season, when water was in short supply, the number of stress days increased at the rate of 1.4 days/100 m of distance between the farm and the turnout. This applied to an area with a farm ditch density of approximately 12 m / h a . In an average situation, with an overland flow distance of 250 m, Wickham and Valera (1976) estimated that this increase in stress days would cause a yield reduction of 0.1-0.3 t /ha, equivalent to approximately 5-15% yield reduction in an average farm field. In other studies, Tabbal found that during the dry season, farms situated farther than 300 m from the turnout, showed significantly more stress days than those nearer the turnout, but only on light or medium soils. He concluded that the problem of on-farm conveyance in the Philippine context is primarily one of gradually reduced supplies to the distant farms, rather than the denial of water to these areas.

( 3 ) Rotational Irrigation at the farm level. An extensive study was carded out in two projects during the dry season of 1974 to compare continuous irrigation with rotational irrigation. Two adjacent irrigated paddy areas were selected in each project: one area was assigned continuous irrigation, and the other - rotational irrigation. The areas had equal but limiting rates of water supply and matched pairs received equal volumes of water. Progress of land preparation, water adequacy and crop yield were monitored. The study showed that there were no significant yield differences between the 'rotational' and the 'continuous' areas. However, it was found that both rotational and continuous deliveries performed much better than the traditionally irrigated paddy areas, due to the improved system of water control. In contrast to the traditional areas, the water deliveries in the research sites were controlled at the turnouts and adapted to the crop water requirements. In discussing the problems associated with better water management, Wickham and Valera ( 1976 ) concentrated on two principal factors: distance along distribution canals, and rotation by canals or sections of a canal. The relevant conclusions are summarized below.

Distance along distribution canals. In order to examine the effect on production of distance along distribution canals, data were collected from eleven irrigated sites in three provinces. The sites were classified according to whether they were irrigated from the headstream, midstream or tailend sections. Mean water adequacy (% area irrigated) and water use (mm/day) were measured for each group. Mean water adequacy in the headstream areas was approximately 10% higher than in the midstream areas and 20% higher than in the

38 LESLIE SHANAN

tail-end areas. Stress days and predicted yield reduction due to stress were much greater in the middle and tail-ends, especially in the dry season. A reduction of 25% was estimated for dry-season yields on the tail-end farms. Head-stream farms generally had more than adequate supplies and relatively low efficiencies in the dry season (aprox. 45%) while middle and tail-end farms in the same season had high efficiencies (approaching 90%), because many experienced serious water shortages.

Similar results were obtained in other studies and Wickham and Valera ( 1976 ) gave the following explanations: "There are a number of interrelated reasons for the tendency to over-irrigate upstream farms and to undersupply the crops' needs downstream. First, siltation has reduced the carrying capacity of most of the older canals along the upstream sections. This means that water must flow at very high elevation, almost to the top of the embankments, to provide enough water for the downstream service area. Since there are many ungated turnouts - some of them unauthorized - along the canal, the water runs freely onto the fields. In fact, it is rather difficult to prevent over-irrigation under these conditions."

"In the lower sections, the opposite problem is encountered. Canal beds have often been scoured and eroded by floodwaters that have found their way into the canal network and eventually drained into a creek or swamp. One often finds cross-sectional areas of downstream canal reaches almost as large as those of upstream sections, despite much smaller irrigation design flows. Available water flows low in the canal and cannot easily serve the adjacent fields. Moreover, the topography downstream is usually quite fiat. Farmers, therefore, open as many turnouts as possible, and resort to checking the water to build up its elevation. These practices aggravate the problem of the farther canal reaches, however, for much less water passes the checks and open turnouts."

Rotation by canal or section of canal. Wickham and Valera ( 1976 ) evaluated the effectiveness of well motivated operational personnel in the distribution of water in a system. They reported on the results various types of rotation operations field personnel had initiated in the field. They found that rotation by laterals and rotation by sections of canals improved the distribution of water between headstream and tailend farmers.

Wickham and Valera (1976) concluded that the on-farm distribution of water in the Philippines in the paddy areas is generally efficient and equitable, and rotational irrigation below the turnout does not improve on-farm distribution greatly. However, they also concluded that the operation of the main system is crucial to improving project performance, and stated:

"A widely-held belief is that poor water management is caused by negli- gence and uncooperativeness of farmers. From this belief stems the idea that farmers should be educated to assume more responsibility in water management, and that as they take on such responsibility, operational functions now

CASE STUDIES 39

undertaken by the systems' field staff can be turned over to them. Although the effects of poor water management are observed on the farmer's field in the form of over-irrigation and drainage, it does not mean that the farmer is at fault. Frequently the flow and elevation of water in the canal - a responsibility of the system - are such that excessive irrigation cannot easily be avoided in traditional systems."

"Efficient water use calls for farmer cooperation in reducing the number of turnouts, keeping them gated, and accepting regulated checking schedules. Most farmers will cooperate provided they get a dependable supply of water. An effective system-wide management program would have two important benefits: ( 1 ) supplying water productively, and (2) eliciting the cooperation of farmers. To the extent that farmers can depend on good management within the system, they can be expected to take more initiative at the farm level. The program to encourage farmers to form irrigation associations would also be enhanced by more predictable main-system management. It is very difficult, however, to convince a farmer to build a potentially useful farm ditch if he feels that there will be no water in the canal to supply the ditch when it is completed."

TAIWAN

Irrigation in Taiwan began in the 14th Century and has been developed primarily for rice cultivation. Of a total of approximately 0.5 million irrigated ha, 85% are operated by a farmers' elected management, called Irrigation As- sociations (Chen, 1980). Four main cropping patterns exist in the following proportions: 60-65%, double rice-crop; approx. 10%, single rice-crop; 20-25%, rotation cropping areas with 2- and 3-year rotations; and up to 5%, upland crops. Rice yields in Taiwan are considered excellent and average approximately 4.5 t/ha.

A basic Water Law, which is strictly enforced by the authorities, governs all matters of irrigation development and management. Irrigation Associations control water delivery in the main canals and laterals, while Irrigation Groups distribute the water from turnout gates through farm ditches to farmers' fields. The 16 Irrigation Associations in Taiwan are corporate bodies organized by farmers, each association managing an average of 25,000-30,000 ha. Irriga- tion Groups are organized by Association members at the farm level for irrigation blocks 50-150 ha in size. These Groups consist of several irrigation teams of 10-15 members each. The Associations prepare an annual irrigation guide for planning each year's operation based on past experience, government policies, farmers' preferences and water availability. On the basis of this guide, the Irrigation Groups prepare detailed irrigation plans which include proposed water delivery schedules, recommendations for crops, areas to be planted, and crop water requirements. The schedules are updated if rainfall

40 LESLIE SHANAN

or variations in the anticipated water supplies subsequently call for changes. The annual budget for the Associations comes partly from a government sub- sidy but mostly from payments by the farmers. These funds cover administra- tive as well as operational and maintenance costs of the networks. A farmer's membership fee generally amounts to approximately 3-4% of his total farming costs.

When compared with other countries, irrigation in Taiwan is considered to be one of the most efficient and most equitable. Levine ( 1977 ) considers that Taiwan is superior to Malaysia and the Philippines in these respects and estimates the comparative efficiency of irrigation delivery networks (i.e., the proportion of water reaching the farmers fields of that amount alloted to the field at the headworks) to be 60%, 20-25% and 40%, respectively.

Under the climatic conditions prevailing in these three countries, it is generally considered necessary to supply 600-750 mm of irrigation water per season in order to cultivate rice with a 95-110 day growing period and for a system with 100% efficiency. Levine (1977) has estimated that actual average deliveries in these three countries are approximately 2500 ram, 1400 mm and 1000 mm in the Philippines, Malaysia and Taiwan, respectively. He ex- plains some of the reasons for the improved water use in Taiwan and considers that the higher efficiency is due to a combination of factors: 24-hour irrigation schedules; effective controls and measuring devices in the network; strict rotational irrigation in the 50-150 ha blocks below the main turnout; extensive and well maintained farm ditches; and a high standard of farmer co-operation.

In another study, Abel ( 1977 ) evaluated the operation of Taiwan systems and identified four main factors which contribute to their exceptionally high performance. First, water has long been recognized in Taiwan as a scarce and valuable national resource and as a costly production input. Farmers realize that water wasted on a farm implies a social cost by precluding its use on other farms or in other productive sectors (industrial, municipal, hydro-electric power, etc.). Second, overall water planning and water allocation are centralized under the government, while the management and operation of the system and its networks are decentralized. The government ensures implemen- tation of its policies while the networks are essentially owned, managed and maintained by the farmers who control and employ the operational personnel. Third, information systems permit the exchange of information (agricultural, economic, technical) between management and farmers. Farmers consequently know their individual allocations before the start of each season and based on past experience, they are also confident that the planned schedules will be adhered to. Water deliveries in Taiwan are equitable, assured and timely. And fourth, the Irrigation Associations have introduced incentives to encourage farmers and network operators to work efficiently and to be efficient users of water. Irrigation water management and regulation are the two

CASE STUDIES 41

main functions of irrigation operation and management in Taiwan. As water resources have become more limited, accurate measurement and distribution of water has become more important. Taiwan is now beginning to evaluate and introduce remote observing, transmitting, monitoring and controlling systems, instead of the conventional manual systems for canal operations (Hu, 1990).

THAILAND

Thailand has approximately 1.3 million irrigated hectares, mostly in the flood plains of the major rivers. In developing the irrigable lands of the flood plains, the Royal Irrigation Department (RID) of Thailand sought to modify the natural flood regime over large tracts of land. The Southern Chao Phya plain, for example, covering more than 500,000 ha, is subject to deep and prolonged flooding. The canals that have been constructed in this area serve a number of objectives - irrigation in certain seasons, flood relief channels in the wet rainy season, and for fisheries and navigation throughout the year. This multi-purpose approach to planning has its shortcomings now that farmers are aiming at higher incomes while at the same time their farms are be- coming smaller as the population increases.

A combination of predominately heavy soils and annual flooding has fos- tered rice as the preferred crop in both the dry and wet seasons. Dry season cropping is diversified on the lighter soils of the alluvial plains and in some areas in the northeast region. Paddy yields have improved during the past decades in irrigated areas and now average 3.8 t/ha. Rice will continue to be the principal crop of Thailand because of (a) the relatively high cost of adapt- ing the large projects to supplying the needs of diversified crops, and (b) the lack of markets for other crops. Rice does well with a continuous supply of water for maintaining ponded water in the fields; field-to-field irrigation is also consistent with this objective. Continuous flow has therefore been the basis of the design and operation of the system networks. Plusquellec and Wickham ( 1985 ), in a review of the irrigation sector in Thailand, also studied water management aspects of the existing systems. Their conclusions, which they believe are relevant to many other countries, are presented in the following paragraphs. Plusquellec and Wickham (1985 ) dealt with six constraints (described below) which, singly or in combination, affect the performance of the systems in Thailand.

Fluctuating river flows. There are large fluctuations in the river flows during the year. The major rivers overflow their banks in the wet season, while water levels drop to low-flow levels during the dry season. The smaller rivers usually have no flow in the dry season. The effects of these seasonal fluctuations have been partly overcome by the construction of upstream storage reservoirs. Careful use of the interseasonal storage has compensated to some extent for

42 LESL1E SHANAN

the uncertainties of the monsoon rains in the wet season, and at the same time assures some limited supplies for the dry season. The degree of regulation of the main water resources varies from project to project and the economic allocation of water for the dry season still represents a serious issue in most projects.

Low coastal areas. The low and flat coastal areas are often less than 2 m above sea level and have practically no significant slope. The quality of the water in the rivers and canals is dependent on the effect of the tide, which has an amplitude of 2-3 m in the Gulf of Thailand. Sea water intrusion consequently affects the salinity levels in the rivers and often prevents use of the water for irrigation for several weeks at a time. The salinity levels in the rivers are affected as far as 60 km from the sea.

Canal system design. The extensive multipurpose canal systems are used for irrigation, drainage, fisheries and navigation. The main canals (excepting for some of the projects designed during the last decade) were designed to be operated at full (or near full) capacity and to meet peak wet season requirements of 0.8-0.9 1/s/ha. This rate of discharge is, however, insufficient to meet dry season peak demands, which are approximately 1.4 1/s/ha. Hence, the present canal capacities limit the extent of dry season cropping. Further- more, fluctuating levels in the main and secondary canals, combined with an absence of sufficient control structures, often result in water levels being too low to command some of the service areas. Finally, no water control structure exists at the last distribution control point in the system - the farm turnout - and this further contributes to unreliable deliveries to the farmer.

Drainage. Flooding is a main bottleneck hindering improved rice cultivation. A drainage and flood control program which would separate irrigation and drainage canals without aggravating downstream flooding conditions has yet to be studied in its entirety.

Incomplete systems. Many projects have not been completed according to the original plans. In some cases tertiary and on-farm systems are lacking, in others conveyance and distribution systems have not been constructed.

Inadequate maintenance. Inadequate maintenance of the existing systems has added to the difficulties of operating the systems efficiently. The principal problems include poor canal maintenance, silting, aquatic weed infestation, and structures damaged (or removed) by farmers. Unfortunately, these shortcomings are common also to the new projects.

In evaluating specific projects, Plusquellec and Wickham (1985) studied the Southern Chao Phya area separately from the Northern Chao Phya. They reported that water distribution in the Southern area, particularly in the wet season, is at as high a level as attainable with the existing system and its controls. Water levels and gate openings are checked and reset according to the estimated crop requirements, and canal levels are remarkably steady. Most of the flood plain is inundated in the wet season and farmers adjust their crop-

CASE STUDIES 43

ping patterns to flooding depths. Where flooding depths exceed one meter, farmers either grow floating rice or forgo the wet season crop and grow a single dry season crop. Main channel storage is relatively large at the end of the wet season, and this volume of water is used for irrigating the dry season crop. In the dry season most farmers have to pump water from the canals to the fields because the canal water levels are generally below the command areas.

On the other hand, in the Northern Chao Phya, the system network is difficult to manage because farmers have damaged or removed most of the gates and because of the large number of ungated farm turn-outs, deliveries in the network are continuous. Plusquellec and Wickham (1985) showed that the water distribution in the Northern Chao Phya project area is characterized by several deficiencies: (a) supplies are unreliable and can fluctuate from minus 50% to plus 200% of the planned delivery; (b) deliveries are not adjusted to utilize rainfall efficiently; (c) water deliveries are not based on crop requirements; and (d) management lacks the authority to prevent overcropping in the dry season. The authors concluded that better management would help to improve irrigation performance to some extent, but on its own it would not solve all the problems of tertiary distribution. They suggest that:

"The preliminary step before choosing an appropriate technology for a project, whether a new project or improvement of an existing one, is the def- inition of the system's water management objectives." These may include: (a) High efficiency in water distribution and productivity; (b) High quality service to the water users; (c) No negative environmental impact; and (d) Equity and fairness of distribution.

"Equity can be achieved either by apportioning the available water contin- uously according to fair users' rights or through fixed rotation depending on the variability of the supply. It requires a simple infrastructure which can be operated with limited staff. However, such rigid distribution does not guar- antee efficiency or maximum crop production."

LESSONS L E A R N E D

Economists have for some years tried to explain how so-called 'well designed' projects perform at much lower levels than expected. They have ap- proached the problem from two principal aspects: - how do macroeconomic policies affect project performance?; and - what are the relative effects of engineering criteria, economic incentives and

supporting services on yields? We will review these two approaches.

Recently, attention has shifted to evaluating the effect of broad national

44 LESLIE SHANAN

economic policies on project performance in the agricultural, industrial and nontradable sectors. The reasons for the shortfalls in performance may lie in a government keeping prices artificially low, for example farm prices, thus giving farmers little incentive to produce; or maintaining a high price for an essential input by imposing protective trade policies, such as the price of fertilizer. Perhaps projects were undermined not by defects in design and operation, but by the broader policy environment of the national economy.

Evidence of this link between government policies and project performance was reported by the World Bank ( 1991 ) after examining 1200 Bank- funded projects in a wide variety of sectors - public, private, agricultural, industrial and so forth. The Bank study evaluated the economic rates of return of the projects against four principal policy measures: - trade restrictions: are prevailing tariffs and quotas limiting production?; - exchange rates: is the official exchange rate far below the black market rate?;

is the black market premium high (200% or more), moderate (20%-200%) or low (less than 20%)?;

- interest rates: are current interest rates positive (higher than the inflation rate ) or negative (less than the inflation rate)?; and

- budget deficit: is it large, moderate or small (more than 8%, 4%-8%, or less than 4% of GNP, respectively).

The results of the study for all the public projects and for the public agricultural projects are summarized in Table 2.3. The study showed conclusively that the average rate of return for all public projects was extremely sensitive to macroeconomic policies. The average rate of return for public agricultural projects, for example, in highly restrictive regimes was 12.1% while projects in relatively unrestricted economic environments had an average rate of return of 14.3%. The effect of the other three factors (exchange rates, interest rates and budget deficits) was even more significant. Where black market foreign exchange premiums were high (greater than 200%), the average rate of return from public agricultural projects was a marginal 3.2% compared to 16.6% for projects operating in an economy with low (less than 20%) premiums. Negative interest rates reduced the rates of return from 17.0% to 12.7%. Finally, high fiscal deficits (more than 8% of GNP) resulted in an average rate of return of 11.7% for public agricultural projects while projects in economies with low fiscal deficits (less than 4% GNP) gave an average rate of return of 18.6%.

The trends as shown for the public agricultural projects were similar to those found for all the sectors studied (Table 2.3). Furthermore, the effect on reducing the rates of return held for all four policy measures. Clearly the evidence indicates that a well designed project in a restrictive economy is likely to be much less successful, from the point of view of economic performance, than it would be if operated in an unrestricted economy, Unfortunately, plan-

CASE STUDIES

TABLE 2.3

Economic policies and average economic rates of return for public projects ( l )

45

Policy distortion index 2 Rate of return (%)

All public projects

Public agricultural projects

Trade restrictiveness high 13.6 12.1 moderate 15.4 15.4 low 19.3 14.3

Foreign exchange premium high (more than 200%) 7.2 3.2 moderate (20%-200%) 14.9 11.9 low (less than 20%) 18.0 16.6

Real interest rate negative 15.4 12.7 positive 17.5 17.0

Fiscal deficit (% GNP) high (more than 8%) 13.7 11.7 moderate (4%-8%) 15.1 12.2 low (less than 4%) 18.1 18.6

~World Bank ( 1991 ) 2See text for explanation.

ners of public agricultural and irrigation projects do not have the opportunity of intervening in the broader aspects of a country's economy and must final- ize their projects within a prevailing economic environment. They must therefore take into account the limitations imposed on their projects by national economic policies. They cannot cover up their failures by claiming, at a later date, that restrictive macroeconomic policies were at fault.

Let us now evaluate how engineering design criteria, economic incentives, agricultural techniques and supporting institutions which are all complementary to the environment, affect performance. Some of these factors are inter- dependent and the interrelationship often makes it difficult to distinguish between the comparative effects of engineering improvements, environmental conditions and institutional structure. The relative importance of these factors, however, was clarified in an IRRI (1975) study in which the rough rice yields (paddy) from 65 village sites in Asia (36 wet season and 29 dry season) were analyzed. Seven factors were considered related to yield: ( 1 ) amount of nitrogen applied per hectare; (2) amount of nitrogen required for maximum yield (based on the results of

46 LESLIE SHANAN

experimental stations in the vicinity of the village, considering soils, climate and rice variety);

(3) percent of farms from each village borrowing from formal sources of credit, such as banks, cooperatives and government agencies;

(4) quality of the irrigation network, ranging from well irrigated to poorly irrigated systems;

( 5 ) type of farming in the village, defined as monoculture or mixed farming, and taking into account two broad soil classes (rice soils and dual-purpose soils) as well as local climatic conditions;

(6) average monthly rainfall for the harvest month and the month prior to the harvest; and

( 7 ) the ratio of price of nitrogen to the price of high-yielding rough rice (paddy rice).

The multivariate analysis was based on the concept that economic, institutional and environmental factors are all important in explaining yield differences between village sites. The three variables in this analysis considered dependent on economic, social and institutional structures were: the amount of nitrogen applied, the price of nitrogen relative to the price of rice, and the percentage of farmers borrowing from formal sources of credit. However, the degree to which these conditions lead to higher yields is governed to a large extent by the quality of the irrigation system. If water is not delivered on time, or if there is a shortage of water, inputs cannot achieve their full objective.

The regression analysis showed that rough rice yield was related to nitrogen input, quality of irrigation, percent of farmers using formal credit, type of farming, and rainfall. Not surprisingly, nitrogen was the most significant variable explaining the variance in yield. Furthermore, irrigation and environment played the dominant role in explaining the variation in both yield and in demand for fertilizer among the different villages. This latter conclusion was particularly important. It enabled the study to determine the relative value of the variables used to explain the difference in nitrogen input between those villlages with high yields and those with average yields. The relative importance of the factors are given in Table 2.4 for rice villages (monoculture) and non-rice villages (mixed farming). Although there is a complementary relationship among the four factors, the two decisive elements that explained differences between villages were the environmental factors and the quality of the irrigation system. This was even more so when the comparison was made between monoculture and mixed farming. Other aspects of the effect of irrigation design criteria on rice yields are further discussed in Chapter 8.

For a given soil complex, irrigation essentially changes the natural environment by 'increasing' the rainfall. Consequently, environment plus the quality of irrigation together explain 80% to 90% of the yield differences between projects. Since the environmental conditions are given for a particular project

CASE STUDIES 47

TABLE 2.4

Relative importance of factors affecting yields ~

Factor affecting yield

Relative Importance (%)

High yielding rice village vs. Low yielding rice village

Rice village (monoculture) vs. Non-rice village (mixed farming)

Environment 50 70 Irrigation system 32 18 Institution 12 8 Price of nitrogen 6 4

qRRI(1975).

area, the quality of the irrigation systems plays the dominant role in explaining differences in the use of nitrogen to achieve higher yields in a specific environment. Irrigation systems should be regarded as the framework for introducing other improvements and should act as catalysts in the process of development. The key question is what steps must be taken, and in what order, so as to relieve constraints on production. Improvements in irrigation should pre- cede other changes. However, full benefits from the improvements will be attained only if all the supporting services combine to assist the farmers to change their traditional practices in order to make maximum use of the irrigation system.

With this background we can now summarize the lessons learned from the case studies given in this chapter, and establish some general principles which contribute to high performance of irrigation systems: - Water must be recognized as a scarce commodi ty to be used as efficiently

as possible; - T h e government must introduce a legal framework to allocate water to

farmers and establish a management system that has the authority to enforce the rules and regulations;

- A high standard of farmer cooperation must exist in the management structure so that the system fosters the interchange of information (agricultural, technical, economic).

The successful introduction of rotational water supply among groups of farmers in projects is dependent on many institutional and operational conditions. A prerequisite for introducing a rotational water supply is that legal means must exist to prevent influential farmers at the head of watercourses from utilizing more than their allocated share. High project performance as achieved in some projects - such as in Taiwan, the northwestern systems of India, and in the improved Water Management Area in the Rajasthan Canal

48 LESLIE SHANAN

- is attained when (a) irrigation water is allocated seasonally to farmers; (b) these allocations are delivered to the farmers according to predetermined 24- hour seasonal schedules; and (c) control structures are maintained efficiently and operated on the basis of ready exchange of agronomic and technical information between farmers and managers.

The World Bank, in a recent report (World Bank, 1987 ) based on past experience in India, establishes guidelines for future planning and discusses how reliable supplies are a sine qua non of improved irrigation projects:

"Several important conclusions can be drawn from these experiences and from more general experience from schemes in India. First, it is not possible to provide service to individual farmers and plots with the infrastructure available in most surface irrigation schemes in India. Consequently, at some level in the system, control must be transferred to the farmers. Second, farmers cannot organize to perform their role in the distribution of water if the supplies they receive are unreliable. Third, reliable supplies can only be assured if the operational plan is realistically framed in relation to the available infrastructure. Ideally, each farmer would receive his allotted share of water on a predetermined schedule, allowing him to plan his operations with minimum uncertainty. In many schemes, this standard is a long-term objective, which can be reached over time through successive rounds of infrastructural and operational improvements."

Performance of 40 projects implemented in 13 countries (Indonesia, Sri Lanka, Philippines, Laos, Malaysia, Korea, Vietnam, Afghanistan, Thailand, Burma, Bangladesh, Nepal and Pakistan) was evaluated by the Asian Devel- opment Bank (1979). Their report underlines the necessity of giving high priority to ensuring that the systems operate with equity and it discusses different strategies for improving irrigation performance. In general, the report recognizes that poor performance in many of the projects was due to poor system operation. Among other conclusions, it was stated that:

"This problem is largely a system problem, since it reflects an abundance of water in the upstream portion of the main canals and water insufficiency in the downstream portion. It also reflects excessive diversions of water in upstream reaches which are considerably greater than crop requirements. This, in turn, is reflected by low water use efficiencies in the upstream reaches. Relatively little water remains to irrigate downstream farms which experience moisture stress and reduced yields. The major problem is equitable distribution of water after it has been diverted from the canals."

Biswas (Biswas, A.K., 1982 ), who has reviewed irrigation projects in many developing countries, reported that in China "...there is no doubt water is used inefficiently in China - like in any other developing country. Probably around 60 to 70% of water withdrawn at present is 'lost'. Management practices are somewhat poor. He Zhi, writing in the national newspaper Guangm- ing Riboa in 1979, pointed out "in China there is no unif'md management

CASE STUDIES 49

department governing water resources, nor are there any laws". This has meant that water development in China is in a state of 'anarchy' and water management is "in a mess, each doing things in his own way". From my personal experience, this judgement is probably somewhat harsh, but there is no doubt improving water management will make a significant quantity of extra water available at a low cost and within a short period of time." Consequently, it would appear that many of the problems and issues described in this chapter regarding poor system performance, exist on an extensive scale also in China.

In reviewing canal irrigation in South Asia, Chambers ( 1988, p. 21 ) has highlighted the problem of poor performance in many projects and states that "the deprivation of tailends is notorious and is confirmed again and again".

In the following chapters we present a system approach to system planning and canal network management and propose guidelines for achieving high levels of performance in both new and rehabilitated projects. In recommend- ing the guidelines, the author has had to choose from among various courses of action. This is typical of the dilemma that the engineer faces when he is called upon to select, in the absence of complete information, the most suitable combination of decisions for his specific project. Consequently, the guidelines are not invulnerable to attack.

Documents

Chapter 2: Case studies