Résumé
The water management in Beauce (one of the most important agricultural areas and of the most important aquifers in France) is changing : reference volume of takings have been imposed to farmers since 1999. The Loire-Bretagne Water Agency asked Cemagref to evaluate impacts of this new water management on farms in terms of cropping patterns, water consumption and incomes. An aggregated economic model was built for each farm type, at aquifer level. It takes into account the variability of yields according to climate, soil type and water suuply. It allows to simulate various scenarii of agricultural policy and global water reference volume.