Large areas of the world are underlain by crystalline basement rock of igneous or metamorphic origin
(Wright, 1992). For many people in arid and semi-arid regions the groundwater stored in these rocks is the
only source of water for long periods of the year. This is particularly true for the rural population without
access to piped water.
This project was undertaken to investigate the factors that control the yield from wells and boreholes in these
aquifers and suggest methods of groundwater development to increase the probability that these yields are
sustainable. The project concentrates on the crystalline basement aquifers of Zimbabwe, but many of the
_conclusions are applicable to other regions of Africa and the-world. The project-highlighted general issues
relating to the sustainability of yield from wells and boreholes as well as producing specific findings with
relevance to groundwater development programmes
