Improving irrigation efficiency to save water: Case of an irrigation scheme in Tunisia[L' amélioration de l'efficience de l'irrigation pour une économie d'eau: cas d'un périmètre irrigué en Tunisie]

The present study, concerning a Tunisian irrigated area, has for objective to evaluate the theoretical cost of m3 of economized water by different investments aiming to improve efficiency reducing losses. This cost, evaluated between 0.010 and 0.040 DT/ m3, has been in a first time compared to the gain of water savings obtained through investments dependent on water price. The incidence of water price and/or different levels of subsidies on investment decisions have been quantified. In this example, the present price of water doesn't incite to save water. Increase of water price or subsidies could promote water savings and assure social equity. In a second time, this cost of water savings was compared to the cost of new resource mobilization. The relationship between the average cost of water economy and the average cost of mobilized water starting from new sources could vary between 1/ 3 to 1/10, according to the sources.