ABSTRACT
For those who live in the humid regions of the world, precipitation is normally so frequent that it is taken for granted. During times of drought the importance of precipitation and its role in feeding the hydrological system and providing water for human use and plant life become all too apparent. In recent years the problems raised by drought in areas such as Afghanistan, Somalia, Australia and even parts of north-west Europe have become publicized in the media as demand for water has increased at a time when some areas have experienced below average precipitation.
