International audienceThis paper assesses the vulnerability to erosion of the soils in the upper Torysa catchment down to the planned drinking water reservoir at Tichy Potok (Slovakia). Experimental observations in the Torysa catchment, together with the outputs of the AGricultural Non-Point Source pollution model (AGNPS), have been used to select optimal sites for small sediment-trapping dams on the Torysa tributaries. The rainfall scenario for the upper Torysa was determined from records at the Plavec climate station from 1980?1998. In addition, an extreme rainfall event scenario was envisaged (100 mm rainfall in three hours); AGNPS model simulations suggest that such an event might produce as much as half or even the total amount of sediment generated by all the rainfalls over the whole period of simulation, 1980?1998. Keywords: erosion, sediment transport, simulation, AGNPS model, Torysa basi