Interregional water transfer is not new: it has been practised from time immemorial. For example, the ancient Egyptians diverted river water over long distances several thousand years ago. But its importance has increased in recent years, especially as population pressures in many arid regions of the world have made it imperative to grow more food. Agricultural production can be increased in two ways—by increasing crop yields and by bringing new land under cultivation. Both of these alternatives can only be viable, provided adequate water supply is available.
As populations in developing countries continue to increase, and since these countries are without exception in the tropics and subtropics, water control is increasingly becoming a major requirement to boost food production. As water resources of populated regions become fully developed, interregional transfer becomes an attractive possibility—provided the environmental and social problems associated with such major projects can be resolved.
Interregional transfer is, however, one of several alternatives of non-conventional water development. There are other possibilities, among which are weather modification, desalination, iceberg towing, and the use of VLCC (very large crude carriers) to transport fresh water to water-deficient regions. None of these are universal solutions, and each must be considered in relation to problems of the region being analysed. In other words, these solutions are site-specific. Furthermore, for most of these unconventional techniques, there exist technological, legal and environmental problems many of which have yet to be solved. In many cases, economic constraints have yet to be overcome.
By Asit K. Biswas, 1978. Article published in Water Supply & Management, Volume 2, Issue 2, pages 79-90.