[Abstract] Results of a series of simulations made in an agricultural catchment in A Coruña using LISEM model are shown. We tried to assess the influence that exert over the runoff and the soil loss factors such as tilling direction, wheeltracks systems, use of grass strips, increasing of random roughness or the increase of hydraulic conductivity. To define the simulated scenarios we used morphologic data of the catchment and supposed refered to plot distribution and land uses as well as input parameters, experimental and bibliographical. In all cases, they were simulated with precipitations with a return period of 2 and 25 years. Under these conditions we estimated that the runoff risk is associated, fundamentally, to intense precipitation events. This risk tend to increase when, as a consequence of tilling, soil infiltration capacity is reduced. Other factors, as tilling direction and wheeltracks systems, influence, more or less, in the magnitude of the runoff produced in a small agricultural catchment
