E Temple-Boyer - CNRS, UMR ۷۵۳۳ LADYSS, Université de Paris Ouest – Nanterre La Défense

This paper is centred on water and soil conservation in Tunisia, resources that pose a dual problem in terms of sustainability and risk, particularly in arid and semi-arid zones. In the Mediterranean region, soil erosion has reached extreme levels. In central Tunisia, on the Tunisian ridge, up to 4 or 5 millimetres of earth disappear each year, carried away by the oueds; added to this is a chronic water shortage (Collinet, 2002). Therefore, at a regional level, soil erosion is identified as a major problem: the soils are threatened by degradation accelerated by intense and ancient deforestation of slopes, as well as the extension of agriculture and livestock farming. In order to compensate for this problem and to reduce the risk of water shortages and environmental deterioration, a large amount of water and soil conservation work has been carried out by the State on these basins since the 1980s. This region of the Tunisian ridge is therefore the subject of a large-scale national water and soil conservation policy that includes, among other things, the creation of numerous hill-reservoirs.