Abstract : The main goal is to evaluate the impact of land-use changes on water resources and to predict their evolution during the next 30 years. The investigation of four landsat images (1975, 1992, 2000 and 2006) allows close detection of the landscape and shows substitution of grassland by trees, especially in higher areas. We use the LCM model with Idrisi software to predict land-use evolution and then the SWAT (hydrological model) to calculate the water flows under these new land-use conditions. The climatic conditions are kept unchanged for the predictive phase. The results show a clear decrease of the flows during the simulation period (1975-2010) which is around 15%. In fact, this observation can be related to the encroachment on landscape of landscape caused by the rural exodus recorded in France since 1970. The reduction in volume could be caused by evapo-transpiration and/or rises in infiltration generating underground circulation.
