Sand dams. Drought is the most serious natural hazard facing Eastern Africa in terms of severity and frequency of occurrence. The most seriously affected areas are Arid and Semi Arid Lands (ASALS) that face frequent reduction of water or moisture to significantly below the normal or expected amount Pastoralists and agro pastoralists who occupy this vast region barely meet basic water requirements. Consequently they suffer from livelihood losses, hunger, diseases, conflict and internal displacements. The worst affected are women and children who may have to walk all day long in search of water.
Due to limited and unreliable rainfall most rivers are ephemeral seasonal sandy bed streams and only experience heavy water run-off for short periods of time after rain. During such periods of high flows, large quantities of sand are transported downstream while others get trapped on the upstream sides of rocks ledges along the stream. Such sand traps form natural aquifers that are capable of providing clean adequate water if well harnessed. Using appropriate technologies this can be exploited for water storage in the form of sand dams.
Appropriate technology (AT) is technology that is designed with special consideration to the context of its use - including environmental, ethical, cultural, social, political, and economical aspects of the community it is intended for. With these goals in mind, AT proponents claim their methods require fewer resources, are easier to maintain, and have less of an impact on the environment compared to techniques from mainstream technology, which they contend is wasteful and environmentally polluting.
The term is usually used to describe simple technologies proponents consider suitable for use in developing nations or less developed rural areas of industrialized nations. This form of "appropriate technology" usually prefers labor-intensive solutions over capital-intensive ones, although labor-saving devices are also used where this does not mean high capital or maintenance cost. In practice, appropriate technology is often something described as using the simplest level of technology that can effectively achieve the intended purpose in a particular location. In industrialized nations, the term appropriate technology takes a different meaning, often referring to engineering that takes special consideration of its social and environmental ramifications.