The suitability of sand abstraction systems for community-managed domestic water supplies.

This paper will discuss the system of abstracting water from the underlying water-bearing sediment of surface dry river beds. The technology is well established in Zimbabwe and is a valuable method of obtaining water for human consumption as well as for both livestock and irrigation use. Within Zimbabwe the system is erroneously but commonly, referred to as "sand abstraction". Apart from traditional methods there are several systems of sand abstraction which have been developed. Each method is dependant on equipment which can be installed into river sands which retain water. Systems range from large mechanized schemes to small scale, hand-operated pump and well screen units. The author, through his work and experience in this area has come to believe that small scale units which can be operated and sustained by local communities are the best option for reliable sources of clean water. In large rivers the sediment frequently retains a perennial supply of water and during a dry-season can provide many thousands of kilolitres of water. The river sands act as a huge, slow sand-filtration system and invariably yield water which is neither contaminated by poor sanitation nor by unpalatable mineral salts. Tests undertaken on water samples drawn from river sands have indicated that contamination occurs only after abstraction from containers. Water utilised from such sources is thus particularly suitable for both primary and secondary purposes. Where such systems can be established on low river banks, not too distant from the river edge, simple sand abstraction units provide an excellent, low cost method of abstracting water. Such systems are particularly appreciated by women who prefer small, low technology installations which they can operate themselves and can maintain simply and effectively.