||EXCAVATION AND DRAINAGE SYSTEMS
Definition characters description and diffusion
Hunter-gatherers used to dig pools under the stalactites in the caves to harvest and store drinking water exuding or dripping from the rocks. In the proximity of the areas where useful wild herbs grew, they dug out pits and little streams, on slopes or before caves, in order to replenish spontaneous vegetation and improve its yield by creating the first artificial irrigation system (Drower, 1954).
General characters description and diffusion
The hunter-gatherers' ability to manage environmental mechanisms regulating water resources on a large scale has been proved, as deomonstrated by archaeological research on Palaeolithic sites and studies made on Australian drainage systems introduced by the Aborigines. Archaeological excavations in New Guinea have brought to light a complex system of drainage channels, built 9,000 years ago, that reached their fullest development around 6,000 years ago (Diamond, 1997). The technique spread over the karst highlands used for agro-pastoral activities to guarantee water reserves to animals. It is a system of soils organization by micro-catchment that enables to cope with climatic conditions ranging from rain to aridity.
Advantages and sustainability
Pools dug in caves were used to harvest dripping water and supply spontaneous vegetation with water. On a larger scale this system can provide animals with water. The technique is very adaptable to varying climatic conditions.