Definition characters description and diffusion
The Andalusian agriculture uses techniques of irrigation through superficial canals fed by wells, systems of water collection through flood diversions or subterranean drainage tunnels (foggara, guettara, qanat, etc.) and are the most suitable for optimising the water use.
General characters description and diffusion
Traditional irrigation allows continuous leaching of the soil and precents the accumulation of salts on the surface, whereas sprinkling irrigation favours evaporation and salt deposits. The building of large dams and water basins generates an accumulation of uncovered water which, stocked in this way, evaporates much more. Moreover, the basin is very easily filled up by the wadi's sediments whereas the upstream subterranean water table of the dam is no longer fed nor renewed. Social associations based on hydraulic rules still exist in Spain, in the region of Andalusia, where they are called alquerie. The alquerie are either the result of the Berber-Arabian migrations or of a reuse of the oldest local habits by these social groups. They organize whole water basins on which the property of several families depends. The water supply of each parcel derives from a network of canalizations and cisterns that intercept the upstream resources and spread them out in the valley thus widening the irrigated area at the margins of the natural riverbed. The layout and the slope of the valley must be perfectly calculated to equally supply all the families since each of them depends on the water systems crossing the other properties. Therefore common agreements regulating every activity are necessary: the location of the fields, the time of irrigation, the choice and rotation of the species planted, which need different qualities of water, the time of private or collective work and the periods of rest as well. Also the areas for settlements is chosen on the basis of precise rules since it has to take into account the areas to be left free for use as water basins and farming spaces to be carefully saved.
Advantages and sustainability
This technique is sustainable because it limits the amount of water wasted and maximizes the amout of water used for other sustainable activities.