The paper starts out by discussing factors which influence the Indian monsoon rainfall—including Northern Hemispheric temperature changes, long-period soli–lunar tides, and the tidelike phenomena associated with the wobble of the Earth relative to its spin-axis. When the effects of these factors on precipitation are quantified and integrated into a thermodynamical–statistical model, long-range climatic forecasts can be made that are better than chance or than predicting ‘normal’ up to two or more years in advance.

Climatic changes have had profound effects on the peoples of India through the controlling influence of the monsoon on Indian agriculture. We now have a technological tool, never before available, that might lessen the impact of variations of the monsoon by forecasting these variations one to two years in advance. The two-years-in-advance 1982 monsoon rainfall forecast for June and July, using the same station models that produced the excellent 1981 forecast, indicates that there is a two-to-one chance that the 1982 Indian monsoon rainfall will be less, in general, in June and July, than it was in 1981. The question which we wish to ask the reader is: How can this new technology be used? For example, how can this type of information be used for planning and policy-making in order to ensure less uncertainty about food supplies in the future than in the past?

This region cannot depend upon the monsoon to bring plentiful rain every year, and, therefore, it is essential that we should continue to improve our forecasting capability and that others learn to make optimum use of these forecasts.

The Nile is the major source of water for irrigation in northern Sudan and Egypt. The need for water is most acute during the dry season, which coincides with the period of low-flow of the Nile. Consequently, intensive studies have been made, since 1904, on the hydrology of the Nile and its control, while dams have been built on the Blue Nile, the White Nile, and the River Nile (i.e. after the confluence of the Blue Nile and White Nile at Khartoum). The concept of storage in the equatorial lakes was also entertained, before the decision was taken on the current excavation of the Jonglei Canal to by-pass the ‘Sudd’ swamps.

A vast literature is available on the hydrology and hydrobiology of the Nile. Nevertheless the present manuscript is seemingly the first attempt to present unpublished notes with a compilation of the published literature. I have also attempted to outline the existing Jonglei Canal Project, which is often confused with earlier-suggested projects.

I advocate that the need for water and the present state of knowledge justify undertaking ‘Phase One’ of the Project, but not ‘Phase Two’. A future paper (now in preparation) will deal in detail with claims that the excavation of the Canal will have drastic ecological repercussions, and will affect the way of life of the local Nilotic tribes.