Learning To Live With Nature: The Lessons of Traditional Irrigation

The ancient civilisations of Sumeria, Babylonia, Egypt, Ceylon and Cambodia, for example, were justifiably famed for their irrigation works. Some of those ancient irrigation systems still survive today, to bear proud witness to the engineering skills of those who constructed them.

Throughout the twentieth century, the construction of dams has continued to be favoured by governments, planners and investors as a relatively cheap and "efficient" method of generating electricity and irrigating land. But, today, the stakes are higher than the ancients could ever have imagined. Advances in concrete technology and the development of vast earth-moving machines - some weighing up to 2,000 tons - have enabled modern Man to build dams of a size and complexity that would have been unimaginable just a few centuries ago.

The statistics speak for themselves. In Egypt, the Aswan High Dam is seventeen times heavier than the great pyramid of Cheops. In Ghana, the Volta Dam holds back a reservoir the size of Lebanon - at 8,500 square kilometres, this vast area of water covers 5 percent of the country. [1] The proposed Bakun Dam in Malaysia will be twice as high as the Aswan High Dam, and will flood an area of rain-forest and tribal homeland the size of Singapore. [2] China's notorious Three Gorges Darn on the Yangtze river will, when completed early next century, have resulted in the forced resettlement of 1.2 million people. [3]

As the ambitions of the dam builders get bigger, so the environmental and social costs imposed by their vast schemes become clearer. The serious and lasting damage done by the construction of huge hydro and irrigation projects has been known for decades. Twenty years ago, hydrologist Dr Raymond Nace issued a stern, and largely-ignored, rebuke to his colleagues at a conference on water-development schemes:

"Three sins beset water planners and their advisers: faith in science and technology: worship of bigness; and arrogance towards the landscape. The belief that technology can solve any water problem ... is wrong. It seems essential that a new frame of mind, some new perspective, be applied to water planning". [4]

Twenty years on, Nace's "new perspective" seems as far away as ever. But if we want to see the development of a "new frame of mind", what needs to be done? What principles need to be applied to water development schemes in the future? To answer these questions, it is not enough to examine only those features which have caused modern irrigation schemes to fail: more important is an understanding of the features which made traditional irrigation societies succeed, and often flourish for thousands of years.

Traditional irrigation lessons from the past

To this day. we can see surviving examples of traditional irrigation schemes, some of which are still in use after thousands of years. The obvious question to be asked when examining them is: why have they lasted, when so many modern hydro-power projects are already failing, only decades after their construction?

Perhaps one of the best examples of sophisticated traditional irrigation known to us is that associated with the qanats of Iran. Qanats are underground conduits, which collect water from an aquifer on the slope of a hill and exploit the land's natural gradient to transport the water underground to the agricultural areas below. Qanats were first developed in Iran but their use spread to India, Arabia, Egypt, North Africa, Spain and even to the New World.

What is astonishing is the number and length of these qanats. There are some 22,000 of them in Iran, comprising more that 170,000 miles of underground channels. [5] Equally astonishing, much of that network was still functioning, just a few decades ago, sometimes thousands of years after the channels were originally built. Indeed, until relatively recently, qanats still supplied 75 percent of the water used in Iran for both irrigation and household purposes.

Most of the area that qanats serve to irrigate is arid and rainless. Without an effective and - crucially - sustainable form of irrigation, such as is provided by the qanats, the development of agriculture across much of Iran would have been impossible. As H. E. Wulff put it:

"they have made a garden of what otherwise would have become an uninhabitable desert." [6]

A particularly important feature of the qanats, as pointed out by Gunter Garbrecht, Chairman of the Working Party on History of the International Commission for Irrigation and Drainage, in 1983, is that they

"tap the groundwater potential only up to an never beyond the limits of natural replenishment and, as a consequence, do not unbalance they hydrological and ecological equilibrium of the region." [7]

In other words, they harness nature but do not overtax it. By contrast, in modern irrigation schemes the amount of water extracted is determined by man, rather than nature; a situation which, more often than not, leads to major problems.

The traditional irrigation system of the Chagga people of Kilimanjaro in Tanzania is another example of the sustainable harvesting of water. The Chaggas have practised irrigation agriculture since time immemorial. Their myths, traditions and religion reflect its importance to their culture and way of life.

Early European travellers who visited the area were hugely impressed by the complicated network of irrigation furrows, or mfongo which collect water from the streams of Kilimanjaro and transport it over long distances to the fields below. Modern engineers have marvelled at the Chagga's irrigation works, admitting that they themselves would require highly complicated equipment to achieve the results which the Chagga have achieved with the simplest of technology.

It is only possible to understand the success of the Chagga's irrigation system as the ethnologist Fidelis Masao points out, through "an understanding of their socio-political organisation and their rituals." [8] The Chagga are organised into clans, which are powerful and cohesive social units. Different clans specialise in different crafts: some, for example, are experienced in tool-making, others in furrow-surveying. The procedure for building a new furrow involves prayers, ancestral offerings and fasts while the work is carried out. The maintenance and repair of the furrows is run by a board of elders, who direct the community to this work.

The Chagga, through their belief systems and high level of social organisation, have constructed an extraordinarily sophisticated irrigation system, with the most basic of tools, which has lasted for centuries and fulfilled their society's needs.

A much more extensive system of traditional irrigation can be seen in Sri Lanka. The island is covered with a network of thousands of man-made lakes and pond, known locally as 'tanks'. Some are thousands of years old and almost all show a high degree of sophistication in their construction and design. Many of the smaller tanks still survive and continue to provide the basis for irrigation agriculture in the dry zone of the island.

Many of Sri Lanka's larger tanks are today silted up and abandoned, while many of the smaller tanks continue to be used for irrigation. It would seem that one reason for this is that larger tanks were often built by the State and in particular by kings, for largely ornamental purposes or simply for personal aggrandisement. The small village tanks, on the other hand, were constructed by local people to supply their water needs.

Sir Edmund Leach, at one time Professor of Anthropology at Cambridge University, argues that although the larger tanks may have been the work of a state bureaucracy, the smaller tanks were constructed and maintained at local level. He writes:

"From time immemorial, normal repair work to the village tanks has been the ordinary work of ordinary people. This must surely be a major reason why they survived for so long - their upkeep is in the hands of the local community, whose needs they still cater for."

The traditional Ceylonese village was dominated by three associated features: the temple, the paddy fields and the tank. Tanks were vital to village life. Often, several types of tank were built: for example, an irrigation tank for the fields, a storage tank for emergencies, an erosion control tank to catch the silt from the inflow of water and prevent the other tanks silting up and a mountain tank to provide water for slash-and-burn agriculture. [11] The tanks would be connected to each other and to the fields by a system of canals and ditches.

Like the qanats of Iran and the furrows of the Chagga, Sri Lanka's tanks provide the villages with only the level of water that the ecosystem made available and no more.

A final example of successful traditional irrigation practices comes from ancient Mesopotamia. Irrigation has been practised along the banks of the Euphrates for thousands of years, in difficult and largely unfavourable flood conditions. Local inhabitants practised irrigated basin agriculture as successfully as conditions permitted throughout much of the turbulent history of the area - the principal weapon against salinisation being alternate-year fallowing.

Such fallowing allows the water table to fall after harvest, a process encouraged by evapo-transpiration from the wild plants that take over once the land is temporarily abandoned. It is unlikely that there is a better means of preventing soil salinisation in the area. Indeed, J. C. Russell has described the traditional fallowing system as:

"a beautiful procedure for living with salinity... the rural villagers understand it, in that they know how it works, they know how to do it and they insist on it." [12]

The contrast between this form of irrigation and those that occurred later in Mesopotamia's history could not be greater. At sometime during the third millennium, there seems to have been a massive increase in irrigation works in the Euphrates valley: not it seems, to improve the irrigation system of the local tribespeople, but to satisfy the requirements of the burgeoning urban society.

The construction of vast canals to supply water to the cities led to seepage. Flooding, over-irrigation and a rise in the groundwater level and was apparently responsible for the increased salinity of the soil which begins to appear in the temple records of the period. Partly as a result of this environmental disaster, Sumerian civilisation began to collapse and many of its cities dwindled to ruins. Adams and Jacobsen, in their study of Mesopotamian irrigation, stated categorically that

"growing soil salinity played an important part in the break-up of Sumerian civilisation." [13]

While the above examples of traditional irrigation practices are extremely varied, their common feature is their ability to harness the power of nature while working within its limits. Unlike the vast dams of the 20th century, they work with the landscape and its ecosystems, rather than in opposition to them and they are constructed and run by local communities, who know and rely on the land, rather than by distant bureaucrats from the cities and towns. Primarily for these reasons, such traditional methods of irrigation have often lasted for millennia.

So, if this is what makes such traditional schemes work and stand the test of time, what can be learned from them? What aspects of traditional irrigation practices need to be applied to modern water developments to ensure their sustainability?

Size: a critical factor?

One of the most striking features of traditional irrigation systems is that they operate on a very small scale. By contrast, most modern irrigation schemes cover large areas of land and are geared towards maximum production. In that respect, it is hardly surprising that their ecological impact is greater than that of traditional systems. The point was well made some years ago by the hydrologist Dr. Desmond Anthony:

'"Experience has shown... that the extent and degree of modification (of ecological systems) and the magnitude of the resultant impact are usually directly proportional to the size of the project and are related to the nature of the environment and its sensitivity to modifications of the kind brought about by construction, operation and maintenance of such projects." [14]

Robert Goodland, who has conducted a number of studies of the environmental effects of large dams in the tropics, is of the same mind. Indeed, in his opinion, "the size of hydro projects is almost exponentially related to environmental impact." [15] That general rule, he says, is true of

"the area of fertile soil removed from annual protection by flooding: the number of people displaced, and houses, infrastructure lost to the reservoir; and the opportunities for the proliferation of aquatic disease vectors (e.g. malarial mosquito, schistosomiasis snail) and nuisance organisms (e.g. water hyacinth, gnats)".

He points out that large reservoirs "trigger or exacerbate the perils of induced seismicity" and "produce less fish per unit volume than small reservoirs." Moreover, "water quality deteriorates gravely in large reservoirs while remaining acceptable in small ones."

For those reasons alone, says Goodland, dams should be as small as possible. Yet despite the environmental advantages of building small dams, small-scale irrigation and hydropower schemes are rarely favoured over large-scale schemes. One reason, undoubtedly, is that large-scale projects earn greater kudos for politicians and engineers alike: the more grandiose the scheme, the more prestige accrues to those involved in building it.

The construction of the Aswan High Dam in the 1950s, for example, was driven as much by the Nasser regime's desire to make its mark on modern Egypt as by any necessity for the construction of such a vast project. Such political considerations continue to play a significant role in dam-building schemes to this day.

So too, as William Ackerman pointed out in his study of the environmental problems associated with man-made lakes, small-scale dams are frequently seen as being 'uneconomic'. Thus, he writes,

"From the viewpoint of power generation and large-scale water-storage, only relatively large and deep reservoirs are economically attractive. One horsepower is generated by dropping one cubic foot of water per second through a height of 3.34 metres. Thus there are obvious advantages to constructing power dams with as much 'head' as possible. Similarly, for water storage, the approximately parabolic shape of most lake basins ensures that each increase in the height of a dam progressively increases the storage benefits. In consequence, major reservoirs are usually made as extensive as possible, and thus they tend to be in the large-scale range." [16]

Why small is not enough

But even supposing that, in future, only small-scale dams were to be built, would that enable us to avoid the problems associated with today's 'superdams'? The answer is undoubtedly a guarded 'no'. Small is certainly preferable to big - and on that point we should be quite clear - but smallness does not, in itself, provide a foolproof insurance policy against ecological damage.

Indeed, the record makes it quite clear that even small-scale projects can cause significant ecological and social harm. In some cases, the damage done is the result of poor design: in others - as in the first of the following three examples - it arises from the very fact that the schemes involved are small-scale. Thus, according to John Hunter,

• the small dams which have been built in the Volta Valley provide a more suitable breeding ground for the black flies which carry the disease onchocerciasis, or river blindness. "In many areas", he reports, "the construction of small dams has already augmented the spread of river blindness, rather than the reverse." [17] The reason is clear - the more dams there are, the more spillways there will be and hence more breeding places for the black flies.
• in Jamaica, bad design led to the failure of a series of small dams which had been built across various shallow valleys in order to convert modest creeks into irrigation reservoirs. Because the subsoil of the region is particularly porous - a fact which the dams' promoters somehow failed to take into account - the water simply leaked away from the reservoirs, leaving the dams high and dry.
• in eastern Nepal, a small hydro-dam silted up so quickly that the turbines stopped functioning. According to "far-away economic experts", the dam was supposed to have repaid its initial investment within 15 years. In just five years, however, it had become a "millstone of modernity around the Nepalese neck".

Seasonal versus perennial

Even the small-scale irrigation schemes built today aim at replacing seasonal irrigation with perennial irrigation. Such perennial irrigation, however, invariably entails costs - whatever the size of the higher social and ecological scheme involved.

Perennial irrigation schemes create a permanent (rather than a temporary) niche for the vectors of the principal water-borne diseases - thus inevitably causing an escalation in the incidence of those diseases.

That problem is exacerbated by the fact that perennial irrigation drastically increases the amount of time that local farmers must spend in the irrigation waters - and hence the amount of time that they are exposed to the vectors which those waters harbour. It also increases the moisture level of the atmosphere and the soil and the vegetative period of crops, thus providing a permanent niche for pests.

We have seen, above, the example of the spread of riverblindness caused by dam-building in the Volta Valley but perennial irrigation is also a significant factor in the spread of the deadly malarial parasite, which is transmitted to humans by the anopheles mosquito.

The introduction of modern, perennial irrigation schemes has greatly favoured both the incidence and lethality of malaria, which remains one of the most widespread and deadly diseases in the world. Flooded rice fields, drainage and irrigation canals and the reservoirs themselves all provide year-round breeding grounds for the anopheles mosquito. In this way, perennial irrigation has greatly hampered the fight against disease.

Although perennial irrigation makes possible several harvests a year, that achievement quickly turns sour where the soil becomes too poor to support the extra demands being made upon it. In that respect, it is important to note that very few soils - and in particular the organically poor soils of the tropics can be used to produce two to three identical crops a year for very long. Indeed, if multi-cropping is carried out over any significant period of time in such regions, it can only lead to the degradation of agricultural land - which in turn must lead to a reduction rather than an increase in agricultural yields.

Equally important, multi-cropping and perennial irrigation tend to raise the water table, inevitably giving rise to all the attendant problems of waterlogging and salinisation which often prove the undoing of major dam schemes. Salinisation is caused by a rise in the salt content of the water in the soil, which in turn is caused or exacerbated by perennial irrigation schemes.

Perennial irrigation has the effect of raising an area's water table, with the result that water held below ground - which is generally more saline than rainwater and surface water - rises, and is drawn to the surface by capillary action. This results in waterlogging of the soil and, as the water evaporates and is 'breathed' into the atmosphere by plants, the salt is concentrated in the soil, which effectively 'kills" it - when the concentration of salts in the soil reaches just one percent, that soil becomes toxic to most plant life. [18]

In the dry tropics, the problem is particularly acute, since there is not enough rainfall to flush out the salts which accumulate in the soil. The problem is exacerbated by the evaporation of water from the vast reservoirs held behind modern dams. John Waterbury calculated that evaporation rates at the Aswan High Dam reservoir increased its salt content by a full 10 percent. [19]

The effect of salinisation and waterlogging can be devastating for the land: a few of the many examples from around the world should suffice to reveal the extent of the problem:

• In Pakistan, 25 million acres of the 37 million acres under irrigation were already estimated to be salinised, waterlogged or both by the mid-1980s. [20]
• In Egypt problems of salinisation and waterlogging have been described as "grave". According to Waterbury, waterlogging alone is estimated to have reduced the country's agricultural productivity by at least 30 percent although it is claimed (perhaps optimistically) that drainage will restore productivity. [21]
• In India, the amount of land devastated by water and salt has been variously estimated at between 6 million and 10 million hectares. In Madhya Pradesh, affected areas are referred to as 'wet deserts'. [22]

For all the above reasons, the very principle of perennial irrigation is unacceptable - on whatever scale it is carried out. That stark reality is tacitly recognised by traditional irrigation agriculturalists. Indeed, for them, irrigation is invariably seasonal and, moreover, it is limited to the shortest possible period. Thus, in the majority of traditional irrigation societies, we find that half the potential agricultural land is allowed to lie fallow on alternate years, thereby ensuring that irrigation is carried out for a short season every other year.

It goes without saying that such an apparent 'waste' of good land is considered intolerable by those who manage today's modern irrigation systems. Indeed, the very idea of 'fallow lands' and 'alternate-year irrigation' goes against all the canons of the modern market system, geared as it is towards increasing production apparently regardless of long-term ecological costs.

The preservation of forests

A further essential feature of traditional agriculture, is that it is practised in areas where part at least of the natural forest cover has been allowed to remain intact. Such forests are particularly important in the uplands and in the watersheds of the river whose waters are abstracted. Indeed, deforestation is by far the most important cause of the recurrent and ever more destructive droughts that today afflict vast and highly populous areas of the Third World.

It contributes to such droughts in a number of ways. Firstly, it reduces rainfall. Thus, in Amazonia, 75 percent of the precipitation is estimated to be derived from the transpiration of trees in the area, which means that once the Amazonian forest is cut down, one can expect a significant reduction in rainfall throughout the region. It appears that the Harrapan Desert in Pakistan was once a vast rainforest whose rain fall was also largely self-generated, so that once the trees were cut down, rainfall was reduced to near zero. [23]

But the recurrent droughts are not necessarily the result of reduced rainfall. Droughts are regularly reported in areas where there has been no recent reduction in rainfall. Such droughts are simply the result of a lowered water table caused by deforestation, excessive water abstraction, or else they are due to the reduced water-retaining capacity of an overtaxed soil.

The general desiccation caused by deforestation in India was eloquently described by E. Washburn Hopkins nearly a century ago:

"All that great bare belt of country which now stretches south of the Ganges - that vast waste where drought seems to be perennial and famine is as much at home as is Civa in a graveyard - was once an almost impenetrable wood. Luxuriant growth filled it: self-irrigated, it kept the fruit of the summer's rain till winter, while the light winter rains were treasured there till the June monsoon came again. Even as late as the epic period, it was a hero's derring-do to wander through the forest-world south of the Nerbudda, which at that time was a great, inexhaustible river, its springs conserved by the forest. Now the forest is gone, the hills are bare, the valley is unprotected and the Nerbudda dries up like a brook, while starved cattle lie down to die on the parched clay that should be a river's bed." [24]

The deforestation of upland areas is even less tolerable, since forested uplands attract a great deal of rain and it is in the uplands that the sources of the rivers, that water the plains beneath, are situated. This is undoubtedly so, for example, in Sri Lanka, where the water required for the vast water-development schemes being built today is unlikely to be available now that the uplands have been deforested.

One might add that, already, the autumn monsoon - which blows from the south-west and which used to collect moisture from the forest uplands and deposit it on the dry zone beyond - now falls on denuded mountains, hence, the autumn rains have largely vanished from the north-east of the island.

Deforested slopes are, in the tropics in particular, very rapidly eroded and the soil which is washed off them raises the river beds, causing floods which can be as devastating to agricultural production as are the droughts to which the same areas have become so prone during the dry season.

What is more, the forests can provide water in perpetuity - not just temporarily - and at no social and ecological cost. On the contrary, they provide other equally precious benefits. For instance, they harbour a wealth of wildlife. They are a source of all sorts of wild fruit and berries, of humus for the fields and of timber for building houses, as they are of the herbs required for traditional medicines and for vegetable dyes.

Seen from the point of view of the wider area, they also generate oxygen and absorb carbon dioxide and generally exert a stabilising influence on climate. In addition, all these benefits are free and thus available to all - not just to the urban elite which alone benefits from the building of large dams.

Water: balancing consumption with availability

A further characteristic of traditional irrigation systems is that those who operate them do not draw off more water than is guaranteed by the natural rate at which their water supplies are replenished. In other words, they do not try to extract more than the 'safe yield' of their aquifers and surface waters.

To that end, traditional societies have historically sought to prevent any increase in the demand for water. In his study of irrigation agriculture in mediaeval Valencia, for example, Thomas Glick shows how all new developments which might have placed a strain on the region's 'water budget' were strenuously resisted. [25] So too the anthropologists Robert and Eva Hunt noted the general tendency within traditional irrigation societies "to resist new [water] uses" even where that entails refusing to open up new lands or to plant new crops. [26]

In arid lands, such restraint is clearly axiomatic if water supplies are not to be overtaxed and if the long-term availability of water is to be assured. That simple axiom, however, is one which modern industrial society with its emphasis on growth - has preferred to ignore. Instead, it has hoodwinked itself into believing that water should not (and, indeed, does not) place a constraint on Man's activities. The philosophy is simple enough: if water is not available locally, then Man's ingenuity will ensure that it is supplied from elsewhere.

In that respect, it is worth considering the history of agricultural development in the US Southwest - a history which illustrates perfectly the conflict between what might, respectively, be called the 'ecological' and the 'industrial' views of water demand and water supply.

Thus, in the late 1880s, ecologically-minded people - notably John Wesley Powell, who later became Director of the US Geological Survey - began to warn that the arid Southwest must learn to live within its water budget if future shortages were to be avoided. Emphasising the natural limits of the arid West's water resources, Powell wrote

"Only a small portion of the country is irrigable. The irrigable tracts are lowlands lying along the stream. These lands will maintain but a scanty population." [27]

That eminently 'ecological' view of water supplies was not to the liking of Powell's contemporaries. Indeed, as the historian Henry Nash Smith observes, Powell "was asking a great deal: he was suggesting that the West should submit to rational and scientific revision of its central myth" - the myth, that is, that there was enough land and water available for everyone's needs.

Perhaps it was inevitable then, that Powell lost his battle to make the farmers of the Southwest see sense. His recommendation that the West should tailor its development plans "to fit the limits of its natural resources" was rejected by the US Congress, "with senators and congressmen from the region itself providing the stiffest opposition." [29]

At the 1893 International Irrigation Congress, held in Los Angeles, Powell was greeted with catcalls and boos. He was, however, undeterred, "You are piling up a heritage of conflict and litigation over water rights", he warned his detractors, "for there is not sufficient water to supply the land." [30]

By rejecting Powell's advice, the American establishment effectively chose to turn a blind eye to the "nature of land, water and climate" in the Southwest. Underlying that intransigent denial of ecological realities was the growing belief that the natural world was something to be shaped at Man's whim to satisfy his immediate requirements.

With the development of modern science - and in particular, the belief that technology can free Man from previous ecological constraints - that attitude has become more and more firmly entrenched. Even well-established hydrological principles have been abandoned where they reflect the need to limit water demand. In the mid-1960s. for example, the US Geological Survey (USGS) simply dropped the notion of 'safe yield'. By way of explanation, H E Thomas of the USGS wrote:

"wholesale depletion (of groundwater) may be economically feasible in the long view if it results in building up an economy that can afford to pay for water from a more expensive source." [31]

It is a view which is hard to swallow. What happens when the "more expensive source" is depleted? Even supposing that another (presumably even more expensive) source of water is available, it can surely only be a question of time before the economy becomes dependent on a source that is so expensive that no-one can afford to buy its water - at which point, the whole economy simply collapses. It is a situation which has already almost been reached in the US Southwest.

Thus, though many billions of dollars have been spent on numerous water-development schemes in the area (California has the dubious privilege of possessing almost one tenth of the world's large dams), irrigation in the Southwest can - in the view of many experts - only continue on any significant scale if the Federal Government is willing to subsidise such mammoth schemes as the peripheral Canal and the North American Water and Power alliance.

Fortunately, both of these vast projects were vetoed as being too expensive. Even if the money were available from the Federal coffers, who would be able to afford water?

Village Elders versus distant bureaucrats

If traditional irrigation systems run so smoothly, it is largely because those who manage them are not members of an alien bureaucracy imposed on local farmers by the State. Instead they are closely integrated members of the very community which farms the land: consequently, their own personal interests largely coincide with those of their fellow farmers.

Furthermore, the knowledge they employ in designing and operating their local irrigation system is knowledge which has been handed down from generation to generation. It therefore reflects the total experience of running an irrigation system in the specific geological, biotic and climatic conditions under which the society must operate.

Finally, those who manage a traditional irrigation system have a vested interest in its success; if they fail to do their job properly, then it will not only be their neighbours who suffer, but their own families as well.

By contrast, modern irrigation schemes are invariably run by distant bureaucracies whose officials are uninvolved and uninterested in the daily life of the communities they oversee. Moreover, the tendency for bureaucracies to seek to perpetuate themselves has frequently meant that senior officials have ridden roughshod over local environmental and social considerations.

So too, in the pursuit of short-term political gains, and in the desire to expand the influence of their own department, those same officials have shown themselves singularly susceptible to lobbying by powerful commercial pressure groups. Inevitably, one finds that the latter's financial interests are then often put above those of the local communities which a particular irrigation scheme is intended to serve.

What is true of the upper echelons of a bureaucracy also tends to be true - though to a lesser extent - at the local or regional level. The inability of local bureaucrats to manage irrigation works with the same degree of equitability and efficiency displayed by traditional irrigation societies is legion. And is there any wonder?

Unlike those who manage a traditional irrigation system, the bureaucrats in charge of a modern irrigation scheme are unlikely to have any practical experience of agriculture in the region: nor are they able to draw on the storehouse of information which a traditional society builds up by farming the same land year after year.

Carl Widstrand, in his 1980 study of conflicts over water resources, pointed out that the assumptions underlying the development of large scale irrigation works "are never based on sound knowledge". Indeed,

"the peasant has very much more knowledge of local conditions than the local administration ... [this] creates an instant conflict between the cultivator, who knows his environment and who knows how to manipulate it and the government extension, who does not understand that the peasant lives by his wits and not by his hands alone." [32]

Instead of genuine local knowledge, the local bureaucrat must rely on a few vague generalities gleaned from the textbooks written by academics who rarely have any knowledge of local conditions. Even where that general knowledge is supplemented by feasibility studies carried out prior to the setting up of a scheme, the hapless bureaucrat is still in an unenviable position - for such studies rarely give any real indication of the problems involved in irrigation agriculture, their primary function being to justify decisions which have already been taken at a higher political level.

The result is frequently a cynical shell-game, in which bureaucrats pass their brief period 'in the field' by passing the buck for failures from one department to another, whilst doing their utmost to claim credit for any successes. Therein lies the path to promotion.

Nor should we be surprised by such naked opportunism. It makes little difference to a bureaucrat whether a new irrigation scheme fails or succeeds. If it fails, it is likely that the bureaucrat will have moved to another post long before the failure can be blamed on him: he is not accountable - and it will not be he who suffers the consequences of failure. Unlike the peasants who must make their livelihood from the land they farm, the bureaucrat's income is assured - and with it, his sustenance.

Food for local consumption rather than export

Perhaps the most important feature of traditional irrigation agriculture is that it is geared to producing food for local consumption rather than for export to some distant land. Indeed, it is only by eschewing the export market that irrigation schemes may fulfil the purpose for which they are overtly designed: namely, to serve the interests of local people. It is also the only way in which it is possible for irrigation agriculture to be effective and sustainable.

To produce enough food to feed itself, a society need not of necessity devastate its environment. Once, however, it becomes geared to producing food for export to a highly competitive - and at times seemingly insatiable - world market, such devastation is unavoidable. Indeed, to export successfully, agricultural activities must be undertaken by vast, capital-intensive enterprises and society must be willing to subordinate long term social and ecological considerations to the overriding goal of short term economic competitiveness. Otherwise, such enterprises simply would not survive.

The majority of irrigation projects in operation today are used to grow cash crops for export, and this has been the case ever since large dams began to be constructed. Vast areas of the Third World have been turned over to the production of such crops. In the Philippines, for instance, over half the country's prime agricultural land is now used to grow cash crops. [33] So too, almost half of all the farmland In Central America and the Caribbean is used to raise cattle or crops for export. [34]

Since the end of the Second World War, the expansion of cash crops for export has been phenomenal. In just ten years between 1955 and 1965 - the production of export crops worldwide grew twice as fast as the total agricultural growth rate of the Third World.

Under such circumstances, the dams that store the water for irrigation schemes cannot be small. Everything conspires to make them bigger and bigger. Nor can irrigation schemes possibly be seasonal: perennial irrigation is essential if vast stretches of water-intensive monocultures are to he multi-cropped year after year.

Nor, too, can forests be preserved. Put bluntly, there is no room for them. Moreover, exporting their timber provides an essential source of the foreign exchange needed to finance capital-intensive development schemes.

Nor can the over-use of water be avoided. All the water that can be made available must be abstracted in the interests of economic competitiveness and of maximising economic activity.

Nor, of course, can export orientated irrigation schemes be managed by local communities. Widstrand, for example, notes the failure of 'water-user associations' in the Third World and the high death rate of government-introduced co-operatives in East Africa. But should we ever have expected such schemes to succeed?

Why should peasants willingly associate themselves with projects designed to export food, grown on the only land available to them for producing the wherewithal to feed themselves and their families, in exchange for money which will be spent by an urban elite on expensive imported goods? To expect peasants to co-operate in such a venture is surely absurd.

The need for a new world view: the 'ecological' approach

Inevitably, the conflict between the 'ecological' and 'industrial' views of water supplies in the US Southwest raises more general questions about our attitudes towards both nature and economics. Can we really take the view that it is justifiable to jeopardise future water supplies in the interests of economic growth? Is it really 'economic' to expose vast numbers of people to malaria or schistosomiasis in exchange for the hydroelectricity or irrigation water that a dam provides? Where, too, is the 'economy' in transforming good agricultural land into a salt desert for short-term increases in agricultural yields?

Clearly, our ideas of what is 'economic' need serious re-thinking. The point is well made by Robert Goodland:

"Economics exclude consideration of ... adverse consequences - frequently referred to as 'externalities' - from customary evaluation. The time-frame of economic thinking is so short-sighted, and the perspective of economic vision so narrow, that such criteria frequently act to the detriment of the environment." [35]

He goes on to note: "In the final analysis, anything environmentally unsound can never be economically healthy."

Sooner or later, all social and economic costs must be translated into economic costs, be it in terms of higher health bills or diminishing agricultural returns. By incurring such costs, we are effectively signing post-dated cheques against future generations - cheques which one day will be presented for payment.

When that day comes, it is unlikely that we will have put enough money aside to meet the debt we have built up - indeed, we will probably have forgotten that we even 'signed' the cheques in question. The only outcome of such short-sighted behaviour is ecological and social bankruptcy - and such must eventually be the fate of all countries that place day-to-day economic and political considerations above the long-term health of our physical and social environment.

That inexorable truth is again well-illustrated by the history of the Dustbowl Years in the United States. On basic ecological grounds, the fragile soils of the southern plains should never have been put under the plough - a fact which was recognised by the Mexican government as far back as 1825 when it decreed that its plains should only be used for ranching. John Wesley Powell (among others at the US Geological Survey) was also of the opinion that ranching offered the only sustainable means of farming the southern plains.

To the American government, however, ranching smacked of feudalism: it suggested an "undemocratic policy" which would result in the setting-up of "great land-owning barons" whose interests could only conflict with those of the small homesteader. Even religion was used to justify the popular view that the plains should be cultivated: God, it was claimed, intended "not cattle but wheat" to be raised on the plains.

The plains were thus cultivated - and the great dustbowls of the 1890s and 1930s were the inevitable consequence. When, in 1936, the Great Plains Committee (under the chairmanship of Maurice Cooke) reported on the ensuing tragedy. It vindicated the warnings of Powell. As the committee wrote,

"Nature has established a balance by what, in human terms, would he called the method of trial and error. The white man has disturbed this balance - he must restore it or devise a new one of his own."

The Great Dustbowl, the committee insisted, was a wholly man-made disaster, the result of a series of misguided efforts

"to impose upon the region a system of agriculture to which the plains are not adapted." [36]

Significantly, Cooke and his colleagues went on to criticise the prevailing attitude

"that Nature is something of which to take advantage and exploit - that Nature can be shaped at will to Man's convenience".

They went on to comment:

"in a superficial sense this is true - felling of trees will clear land for cultivation, planting of seeds will yield crops and applications of water where natural precipitation is low will increase yields. However, in a deeper sense, modern science has disclosed that fundamentally nature is inflexible and demands conformity... we know now, for instance, that it is essential to adjust agricultural economy on the Plains to periods of deficient, rather than of abundant, rainfall and to the destructive influence of wind blowing over dry loose soil rather than primarily to a temporary high price for wheat or beef - that is our way, not Nature's, which can be changed."

Herein lies the crux of the matter. Living things are not arranged in a random manner. Nature is not totally malleable, as those who wish to transform her would have us believe. She is, on the contrary, highly organised - and maintaining that organisation is critical to her proper functioning. Once degraded by over-exploitation and pollution. Nature cannot hold her own.

Cut down forests and overtax the land and soils will become eroded: pollute rivers, and fish will die: upset the natural balance between potential pest and predator and pest epidemics will break out; destroy the habitat of wildlife and species will pass into extinction.

Indeed, the whole gamut of ecological ills which now beset the earth should be seen as but the symptoms of a degraded Nature, which under pressure from industrial Man, can no longer continue to function properly. If those ills have, historically, been avoided by traditional societies, it is above all because they recognised the simple axiom that "it is our way, not Nature's, which can be changed."

References