ABSTRACT
The new hafirs have not been wasted, for they have permitted crops to be grown and harvested where previously the land lay fallow, but they have not led to any significant change in the pattern of population distribution, and they have not much reduced the pressure on the land near the original settlements. It is probably because the Gezira Scheme and other government irrigation schemes elsewhere have apparently been so successful that the difficulties inherent in bringing about lasting changes in the distribution of population through conscious planning have not been fully recognized. The Westerners are a heterogeneous population, for they come from many tribes, usually moving as individuals or in small groups. Population is concentrated along the water-courses which drain Jebel Marra, because these are flanked by broad alluvial terraces in which particles of pumice and clay derived from the volcanic rocks combine to make a fertile soil which is easy to work.
