ABSTRACT
Rainfall collection, runoff concentration and rainwater harvesting are all broadly synonymous terms used to describe the collection and concentration of rain falling on natural slopes, cleared and compacted slopes or sealed catchments, to irrigate crops or supply water to livestock or meet domestic needs. Traditional water-lifting devices have long been used to raise water from rivers or lakes, either to irrigate land which remains above water all year round or to extend the growing season and boost the yields of crops planted on flood lands after floodwaters recede. There is some disagreement in the literature over the quantities of dew formed in the tropics, its actual value to natural vegetation and its potential for supporting crops. However, it has been argued that most of the moisture they collected was derived from rain rather than dew or mist. Fog and mist are presently insignificant sources of water, but in some localities they might offer promise.
