Process-based soil erosion models, such as the European Soil Erosion Model (EUROSEM), have the potential for the extrapolation to the catchment scale of plot scale investigations into the effectiveness of soil conservation practices. Results from plot scale studies on the effectiveness of live barriers for soil erosion control on steep mountain sides in the Cochabamba region of Bolivia, are used to evaluate EUROSEM. The model is then applied to a 3 ha catchment in Pairumani, Cochabamba. The catchment consists of 28 fields of varying sizes and slopes (between 20 and 30 percent). The model was parameterized for the existing conditions using parameter values derived from field survey and from existing experiments in the area. A rainstorm, which would have a return period of five years in Cochabamba, was constructed and soil erosion and runoff dynamics were simulated in the catchment. Grass barrier strips were then introduced into the simulation, at a spacing of 9 m; the simulation results were then compared. Results illustrate estimated reductions in soil erosion of 185 kg at the catchment outlet and up to 1,404 kg for individual fields within the catchment. The potential of process-based erosion models for simulating the impact of soil conservation systems in mountain environments is demonstrated.