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Chapter 1.Long-distance water transfer: problems and prospects

Asit K. Biswas
President, International Society for Ecological Modelling
Past Vice-President, International Water Resources Association
Director, Biswas & Associates, Oxford


WATER is used for a wide variety of purposes, chief among which are domestic use, industrial use (including mineral extraction and processing), irrigation, hydroelectric power generation, navigation, recreation and fisheries development. The extent of water use for any one purpose varies from one country to another, and is dependent on a variety of factors like state of economic development, including standard of living; importance and extent of a specific sector like industry or agriculture in the national economy; efficiency of water use; socio-cultural practices, and so on. For example, for two industrially advanced countries like Japan and the United States, industrial water use in terms of per capita per day varies from 4,500 litres for the former to 9,600 for the latter, a figure that is more than twice the usage rate for Japan. Similarly for the United States, total agricultural and industrial water demands are somewhat similar: approximately 40 per cent of total water requirements. On a global basis, however, the situation is very different: agriculture is the largest user of water and accounts for nearly 80 per cent of total consumption.

Water is a renewable resource and, unlike non-renewable resources like oil or natural gas, there is no danger that the world is going to run out of water. The principal problem with water is that its distribution varies tremendously both with respect to time and space, and accordingly its rational management is of paramount importance for the welfare of mankind.

While the total amount of water available in the world can be considered to be fixed for all practical purposes, the amount available can certainly meet vastly higher human needs if used more efficiently. Approximately 71 per cent of the earth's surface is covered with water, most of which is saline. Current estimates indicate that the total volume of water on earth is 1.4X109 km, 97.3 per cent of which is ocean water and therefore cannot be used by man except for fisheries and navigation. Only 2.7 per cent is fresh water, 77.2 per cent of which is stored in polar ice-caps and glaciers, 22.4 per cent as groundwater and soil moisture (about two-thirds lies deeper than 750 metres below the surface), 0.35 per cent in lakes and swamps, 0.04 per cent in the atmosphere and less than 0.01 per cent is in streams (Biswas, 1979a). This means nearly 90 per cent of fresh water is stored in ice-caps, glaciers and as deep groundwater, and as such is not easily accessible. For all practical purposes, it is surface water in rivers, streams and lakes, amounting to less than half of one per cent of available fresh water, that constitutes the basic available supply for man, even though groundwater has been heavily developed in certain parts of the world.


With increasing global population, more and more water will be required for different uses. Furthermore, current evidence indicates that water requirement per capita increases with improvements in the standard of living. It is, however, extremely difficult to make meaningful projections for future global water requirements since efficiency of use is a most important consideration. Two major water users are the agricultural and industrial sectors, and the potential for more efficient water management in both these sectors is enormous. For example, identical industrial products are being manufactured in the same country, say the United States, where one factory uses only 2 per cent of the total water needs of another, per unit of product, by using extensive in-plant recirculation and treatment technologies (Biswas, 1979a).

There is no doubt that the agricultural sector is the major user of water for most developing countries. Water requirements naturally vary tremendously from one country to another, depending on different factors, among which are total land under agricultural production, types of soils and crops cultivated, climate, availability and pricing of irrigation water, efficiency of water use and management practices. Agriculture is water intensive and, on average, it takes approximately 1,000 tons of water to grow one ton of grain and 2,000 tons of water to grow one ton of rice. In addition, both animal husbandry and fisheries require abundant water. If the current trends continue, future water requirements are going to increase tremendously. The average annual water withdrawal per unit of land area by continents and selected countries is shown in Table 1 (Barney, 1981).

In 1975, the total area irrigated in the world amounted to 223 million ha, of which 93 million ha was in developing countries. Some 15 per cent of the world's cropland is irrigated, but it yields from 30 to 40 per cent of all agricultural production. The amount of water used by irrigated crops is nearly 1,300,000 million m but, because of losses in storage, conveyance and use, the total amount used increases to almost 3,000,000 million m (FAO, 1978).

It is estimated that by the end of the present decade in 1990, the total area irrigated in the world will increase to 273 million ha, of which 119 million ha will be in developing countries. Expanding and maintaining irrigated areas to 1990, including provision of adequate drainage, is going to be a challenging task, and its magnitude is shown in Table 2 for the developing market economy countries only. The investment cost is estimated at $97,500 million in constant 1975 dollars (FAO, 1978).

Without major improvements in efficiency for water use, more and more water will be required to sustain and improve present agricultural and industrial developments and more will be necessary for future developments. Certain parts of the world have already started to face water shortages, and if the present trends continue, the situation is likely to become worse in the future. Some people have already claimed that water will soon become one of the major constraints for future economic developments.

Table 1 Average Annual Water Withdrawn per Unit Land Area by Continents and Selected Countries

Geographical area Land Area
6 km)(mm/yr)
Average Annual
Africa 30.6 2.88
Egypt 1.0 30.0
Asia, excluding USSR 27.7 57.7
India 3.29 9.12
Indonesia 1.93 3.11
Japan .372 301
Pakistan .804 147
Philippines .300 46.7
Thailand .514 38.9
Turkey .781 28.2
Australia, New Zealand & PNG 8.42 3.56
Australia 7.69 3.25
Europe 27.2 19.0
USSR (Europe and Asia) 22.4 13.2
North & Central America 22.1 24.9
United States 9.36 51.0
South America 17.8 3.20
Brazil 8.51 1.18
Global (excluding Antarctica) 134 21.2

Table 2 Irrigation and Drainage in Developing Market Economy Countries, 1975- 1990

  Africa Latin
Asia Total
IRRIGATION (thousands of hectares)          
Equipped irrigation area, 1975 2,610 11,749 17,105 60,522 91,986
Targets for 1990          
New irrigation 960 3,101 4,295 13,848 22,204
Improvements to existing irrigation 4,698 9,789 29,718 44,988  
minor 522 2,349 6,368 17,614 26,853
major 261 2,349 3,421 12,104 18,135
Increased water demand (103m) 20 33 44 341 438
DRAINAGE (103 ha)          
Equipped drainage area, 1975 7,044 46,585 18,212 62,501 134,342
Improvement targets, 1990 5,900 19,245 9,643 43,396 78,184
on irrigated land 1,177 2,018 7,076 42,152 52,423
on non-irrigated land 4,723 17,227 2,567 1,244 25,761

Groundwater is being increasingly exploited for agricultural development. In many parts of the world, groundwater withdrawal rates are exceeding natural recharge rates, and thus contributing to groundwater mining. Even in an advanced country like the United States, groundwater use is rising more rapidly than surface water use, and nearly 25 per cent of all groundwater withdrawals,in 1975 in that country amounted to mining (CEQ, 1980). For example, in the San Joaquin Basin in California, United States, approximately 1.85x109 m more water is pumped every year than is recharged naturally. Since this overdraft accounts for some 12.5 per cent of San Joaquin's annual water supply, its long-term sustainability has to be seriously questioned. The situation is somewhat similar or even worse in most arid developing countries.

In nearly all arid developing countries, faced with the twin problems of increasing population and the need to feed that population properly, planners and decision-makers are looking for means to increase irrigation water availability so as to increase agricultural production. They are exploring alternatives to alleviate what often could be considered rapidly developing critical situations. One possibility several countries are exploring at present is to transfer water over long distances from water-surplus areas to deficient areas. Already, some projects have been constructed in different parts of the world to divert water from one basin to another.

Long-distance mass transfer of water is, however, only one of several alternatives of non-conventional water development. Several other possibilities are being explored, among which are weather modification, desalination, iceberg towing, and the use of very large crude carriers (VLCC) to transport fresh water to water-deficient areas. Some of these alternatives are still in the research and development stage, and cannot be used economically for large scale agricultural development. Others, like desalination, can be used only for site-specific solutions, and can produce only a limited quantity of water, which means it is somewhat unlikely at present to be used economically for extensive agricultural development.


Conceptually, it can be argued that all water development projects involve transfer of water over long distances. Part of rain or snow that falls in one region ultimately finds its way, as surface and groundwater, to a river, which often flows through several regions. At certain locations, water can be stored in reservoirs by damming the river. The water stored in reservoirs can be released as and when required. In other words, water is always in motion and is being continually transferred from one region to another by both natural and artificial means.

In the present discussion, however, the emphasis is not on this type of "normal" transfer: the main focus is on large-scale artificial mass transfer of water from a water-surplus to a water-deficient region in order to further the economic development of the latter, mainly through agricultural and industrial development. This could be achieved by diverting the course of a river, or by constructing a large canal which could carry a significant portion of available water. Both these alternatives invariably have important economic, social and environmental implications which need to be carefully analysed and evaluated before final decisions can be made for their construction.

Before long-distance mass transfer of water can be seriously investigated as a viable policy option, it is essential to carry out a comprehensive assessment of available water resources-both surface and groundwater-in terms of quantity as well as quality. It is a fundamental fact of hydrology that availability of water in a river is a function of both space and time. Thus, static assessment is not a viable option: time-series data of hydrological variables- either real or reconstructed-is an important prerequisite for any analysis. In order that reliable forecasts of water availability can be made, it is necessary to have adequate data over a reasonable period of time. Based on such data, long-term water management plans can be prepared. However, in many parts of the world, such data are not available or, if available, they are for a rather limited time period. Furthermore, very rarely is any information available on their reliability and accuracy. This is unfortunately the case for most developing countries. This is basically the situation with data on water quantity; information on water quality is even more scarce and seldom available, especially in developing countries. Quality of water determines its possible uses, and hence data on water quality are necessary to develop rational management plans. Much progress has to be made in this field.

Other problems associated with data on water quantity and quality, in addition to data scarcity, are non-representativeness of monitoring sites, unavailability of trained technicians to collect data and maintain data collection instruments and monitoring networks, and lack of experienced professionals to analyse the data collected and facilities to store and retrieve data. The situation is further complicated by the presence of different agencies at federal, state and local levels who collect water-related data. Co-operation between these agencies is generally poor and sometimes even non-existent. Accordingly, exchange of data is not always feasible. In the United States alone, at least 20 federal agencies are associated solely with water quality monitoring programmes. Proliferation of data collection agencies often makes the system complicated and in a few cases even unmanageable.

The second important consideration is the assessment of water demands for different purposes. It should be noted that the term "demand", in the context of water resources management, generally means requirements, and is very rarely used in its traditional economic sense. Indeed, very rarely is the concept of demand elasticity explicitly considered within the water planning process per se. Consequently very little is known about constructing realistic demand functions under varying socio-economic considerations. Expressed differently, it means that emphasis so far has been on supply management-that is, increase in supply is considered to be virtually the only management alternative-rather than consideration of demand management. As the water requirements for various purposes continue to increase and available sources become more and more exploited and polluted, it is highly likely that emphasis will gradually shift from supply to demand management.

Efficiency of existing water use is the third important consideration. Undoubtedly, the agricultural sector is one of the most inefficient users of water, and significant improvements could be made here. Existing efficiencies of irrigation systems are so low that they do not by any means reflect the actual water requirements of crops being irrigated. As mentioned, on a global basis, 1,300,000 million m of water is used for irrigation crops, but for this 3,000,000 million m of water have to be withdrawn. In other words 57 per cent of total water withdrawn is lost in the process. This, however, should not be construed to mean that the remaining 43 per cent is efficiently used. Over-irrigation is endemic and not exactly an uncommon practice in both developed and developing countries. It not only means that water is wastefully used but also contributes to development of environmental problems, like increase in groundwater table and salinity level* (M. R. Biswas, 1979a, 1979b).

One of the most inefficient parts of the irrigation system is often the section where water is transferred from canal outlets to farms. It has become a no-man's land due to undefined responsibility, which in turn contributes to improper design and unsatisfactory operation and maintenance. While much research has been carried out on losses from the canal itself, very little work has been done on losses from the transfer sections. Studies carried out on 40 such sections in the Indus Basin during 1975 and 1976 indicated losses ranging from 33 to 65 per cent, with an average of 47 per cent. Another investigation on 60 sections carried out in 1977 and 1978 by Water and Power Development Authority of Pakistan indicated similar losses. The magnitude of this problem can best be realised by considering the case of good lined canals, which are expensive to construct and have operating efficiencies of 70 to 80 per cent. When the efficiency of the total system is considered, i.e. lined canals in conjunction with the inefficient section from canal outlets to farms, the total efficiency is of the order of 20 to 50 per cent, which means that even for expensive, lined and well-maintained canal systems, in many cases only one fifth of water released from a reservoir reaches the crops being irrigated.

A major result of this sad state of affairs is that engineers and planners have accepted this inefficient system, at least implicitly. During planning of irrigation projects, total water requirements are generally calculated by multiplying the area to be irrigated by the water required per hectare. The water requirement per hectare is often estimated on the basis of existing systems, where major portions of water released from reservoirs are lost.

Accordingly, overall estimates of irrigation water requirements are invariably high-certainly much higher than necessary-and the inefficient system is condoned and perpetuated. In other words, most irrigation systems designed so far are inefficient and use far more water than necessary. Unfortunately, instead of attempting to make irrigation systems more efficient and then maintaining them at such levels, engineers are constantly seeking new sources of water for irrigation. They often look for costly alternatives, like interbasin water transfer, when such major and expensive projects are not essential (Biswas, 1978) and cheaper alternatives are available-which can be implemented within a much shorter time frame with indigenous labour and expertise-by simply improving the existing systems. Furthermore, even if new projects are developed, unless special efforts are made to maintain their efficiencies at high levels, their effectiveness will decline with time and thus the vicious circle will continue to be perpetuated.


Several proposals have been put forward in North America in recent years for long-distance mass transfer of water, but undoubtedly the most ambitious one suggested so far is the North American Water and Power Alliance (NAWPA). First suggested in 1964 by Ralph M. Parsons Company of Los Angeles, this $10billion-plus project kindled the interest of many engineers and politicians. Within some six years of the NAWPA scheme being proposed, a whole series of other schemes were put forward to re-distribute the water resources availability in North America. Most of these proposals cannot be considered very seriously at present, since some were based literally on drawing lines on topograpical maps, with very little, if any, analyses of their engineering, economic, political and social feasibilities. The NAWPA project will be briefly outlined here primarily for two reasons: (a) its gigantic scale; and (b) more technical information is available on this scheme than on others.

The fundamental concept of NAWPA is to collect surplus water from the high precipitation areas of the north-western part of the North American continent and distribute it to water-deficient areas in Canada, the United States and northern Mexico. A series of dams and power stations in Alaska and northern British Columbia would collect water and provide power to pump this water up to the Rocky Mountain Trench Reservoir in south-eastern British Columbia. From the Rocky Mountain Trench Reservoir, water would be lifted by pumps to the Sawtooth Reservoir in Central Idaho. From there, the water would flow by gravity to the western states. NAWPA would initially provide 137.5 billion m of water annually to seven provinces of Canada, 33 states in the USA and three northern states of Mexico. The total power generation would be 100 million k W/yr. Out of this, 30 million k W/yr would be utilised by the pumping requirements of the project. NAWPA is a gigantic project and its environmental and social costs have yet to be comprehensively determined. Its international and political implications are quite enormous and have yet to be fully realised. Much of the excess water will originate from Canada and will be used in the United States. Canadian public opinion is solidly against the transfer of such a massive quantity of water to its neighbouring economic giant to the south, the United States. The Canadians fear that once such developments have taken place in the United States to use this excess water, it would not be politically and economically possible to stop the export of water, even after the treaty period of whatever duration is over. They are concerned that in the future, when more water will be necessary for Canada's own use and further development, it would no longer be available. Even if this major international problem was solved in favour of water transfer, and it was further clearly shown that technical, economic, social and environmental problems could be overcome (these have yet to be resolved and in most cases have not even been identified), current experiences indicate that the litigations alone would postpone the implementation of such a project for at least a decade, perhaps even longer. In other words, if present trends continue, it is highly unlikely that construction of such a project would start before the end of the century at the earliest-if it is implemented at all!


There are a number of problems associated with large-scale transfer of water from one region to another. The magnitude of the problems will differ from one project to another, but some of the major variables that should be considered are the following:

I Physical System

(a) Water Quantity: level; discharge; velocity; groundwater; losses.
(b) Water Quality: sediments; nutrients; turbidity; salinity and alkalinity; temperature effects; toxic chemicals.
(c) Land Implications: erosion; sedimentation; salinity; alkalinity; waterlogging; changes in land use patterns; changes in mineral and nutrient contents of soil; earthquake inducement; other hydrogeological factors.
(d) Atmosphere: temperature; evapotranspiration; changes in microclimate; changes in macroclimate.

II Biological System

(a) Aquatic: benthos; aufwuchs; zooplankton; phytoplankton; fish and aquatic vertebrates; plants; disease vectors.
(b) Land-based: animals; vegetation; loss of habitat; enhancement of habitat.

III Human System

(a) Production: agriculture; aquaculture; hydropower; transportation (navigation); manufacturing; recreation; mining.
(b) Socio-cultural: social costs, including resettlement of people; infrastructural developments; anthropological effects; political implications.

The above checklist should not be considered to be all-embracing but rather an indicative one for analytical purposes.


In the past, long-distance mass transfer of water has often proved to be an emotive issue. Every time such a project is proposed, public controversies have become the rule rather than the exception. The proponents argue that their technical excellence, economic benefits and overall contributions to development make them indispensable to society. The opponents on the other hand point out that their total social and environmental costs are far too high and hence unacceptable to society. Thus, in all likelihood, one segment of society will lobby for such a development while another section will oppose the same project for different reasons. To a certain extent, such conflicts can be explained by analysing the nature of the beneficiaries, which is seldom carried out for any water resources development project. It is inevitable that any development project will benefit some citizens more than others and, frequently, some citizens may have to bear additional costs, either tangible (i.e. heavier tax liabilities) or intangible (i.e. social and environmental). The proponents are often the net beneficiaries and the opponents tend to be those who pay the costs.

Even scientists are strongly divided on the question of such transfers. For example, Howe and Easter (1971) have concluded that such water transfers are likely to prove expensive to nations, except under certain "rescue operation" type of cases. But Wells (1971) has pointed out that water imports to the high plains of Texas are not only economically feasible but also that the state simply cannot afford not to import water to that area.

If many of the past and present experiences on long-distance water transfer are reviewed critically, the following major issues emerge:

(1) Mass transfer of water is often justified by considering only the direct cost of transporting water. Seldom are the values of services foregone by the exporting region due to reduction of their water availability, i.e. the opportunity costs of exported water analysed.
(2) Various other feasible alternatives to interbasin water transfer are often not investigated. There is a tendency within the engineering and economic professions to opt for technological solutions-"soft" options tend to be neglected (Biswas, 1979b). Since water resources development is dominated by these two professions, there is a tendency to opt for technological fixes before all viable alternatives are explored. Among possible options are:

-more efficient use of available water;
-re-use of waste water ;
-better management of watersheds;
-improved integration of surface and groundwater supplies;
-changing cropping patterns.

(3) The agricultural sector is usually the major beneficiary of water transfer projects. Thus, much of the analysis often concentrates on agricultural benefits, and social objectives like income redistribution, alteration in regional growth rates and patterns, reduction in unemployment and environmental protection are not considered. To a certain extent this can be explained by the difficulties encountered in quantifying social and environmental benefits and costs.

(4) Opposition to large-scale mass transfer of water in developed countries, especially for interstate and international projects, is likely to increase as more and more water is required for various purposes. Transfer of water from one country to another, or even between states within a country, can seldom be achieved without controversy. Technical and economic feasibility studies are comparatively easy to conduct; the real problem lies in their public and social acceptability. Considered purely from a rational viewpoint, such reasoning is hard to explain since states and countries freely export other resources like minerals, hydrocarbons and agricultural products. Public sentiment, for whatever reasons, often seems to be strongly against water exports and this concern, not surprisingly, is reflected in the political process. This may perhaps be explained by the "water is different" syndrome and in all probability is unlikely to change in the near future.

(5) The legal implications of interstate and international water transfers are quite complicated. Adequate legal and institutional frameworks for such developments are rare, and currently there is no process for speedy resolution of these conflicts. This point can be quickly realised by the present disputes that exist between states and between nations on the use of interstate and international rivers and lakes (Biswas, 1983).

(6) Since the mid-sixties, opposition to mass transfer of water has increased significantly on environmental and social grounds in developed countries. Many segments of society are no longer willing to accept such social and environmental costs as the price of progress.


Large-scale mass transfer of water has been a controversial topic during the last two decades. Instead of taking entrenched and dogmatic views on the topic, each case should be considered on its merits and decisions should be taken accordingly. Attempts should be made to identify and evaluate secondary and tertiary benefits and costs, which are often neglected. Furthermore, feasibility studies should not concentrate on engineering and economic factors only; social and environmental costs should also be considered. Even more important is the fundamental question of whether such costly alternatives are necessary and whether the extra water required cannot be obtained by improving the existing water management process.

While there have been a few interregional water transfer projects in developing countries, these experiences have yet to be carefully analysed and evaluated. It is thus essential to prepare case studies from different countries so that certain generalised conclusions can be drawn which could be used as broad guidelines for other developing countries that wish to embark on similar ventures.


Barney, G. O.,1981, "The Global 2000 Report to the President of the United States", Vol. 2, Pergamon Press, Oxford.

Biswas, Asit K., 1983, "Management of Shared Natural Resources", Journal of Indian Water Resources Society, Vol. 3, No. 1, pp. 7-18.

Biswas, Asit K., 1981, "Long Distance Mass Transfer of Water", Water Supply and Management, Vol. 5, No. 3, pp. 245-252.

Biswas, Asit K., 1979a, "Watera Perspective on Global Issues and Politics",Journal of Water Resources Planning and Management Division, American Society of Civil Engineers, Proceeding Paper 14815, Vol.105, No. WR2, pp. 205-222. Reprinted in Water Resources Journal. Economic and Social Commission for Asia and the Pacific, United Nations, Bangkok, December 1980, pp. 30-41.

Biswas, Asit K., 1979b, "North American Water Transfers: An Overview". In Interregional Water Transfers, Editors G. N. Golubev and A. K. Biswas, Pergamon Press, Oxford, pp. 79-90.

Biswas, Asit K., 1970, "History of Hydrology", North-Holland Publishing Co., Amsterdam, 336 p.

Biswas, Margaret R., 1979a, "Environment and Food Production". In Food, Climate and Man, -Editors Margaret R. Biswas and Asit K. Biswas. John Wiley and Sons, New York, pp. 125-158.

Biswas, Margaret R., 1979b, "Agriculture and Environment". In Technical Memoir No. 3, International Commission on Irrigation and Drainage, New Delhi, pp. 225-255.

Council for Environmental Quality (CEQ), 1980, "Environmental Quality-1980", US Government Printing Office, Washington, 497 p.

Food and Agriculture Organization (FAO), 1978, "Water for Agriculture". In Water Development and Management: Proceedings of the United Nations Water Conference, Editor Asit K. Biswas. Part 3, Pergamon Press, Oxford, pp. 907-941.

Howe, C. W., and Easter K. W., 1971 "Interbasin Transfers of Water: Economic Issues and Impacts" Johns Hopkins Press, Baltimore.

Wells, D. M., 1971, "High Plains Irrigation and Texas Water Plan", Journal of Irrigation and Drainage Division, American Society of Civil Engineering, pp. 123- 130.

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