Runoff and soil erosion evaluation by the AnnAGNPS model in a small Mediterranean watershed

In order to evaluate prediction models of runoff and sediment yield in a Mediterranean environment, the distributed parameter, physically based, continuous simulation, daily time step AnnAGNPS model was applied to an experimental watershed of mainly pasture in Sicily. Results from AnnAGNPS simulations were evaluated using 7-year data monitored at this watershed. The model showed satisfactory capability in simulating surface runoff at event, monthly, and annual scales after calibration. Peak flow predictions were generally good for low flow events and poorer for higher flow rates. A high model efficiency was achieved for the 24 suspended sediment yield events recorded during the entire period of observation after reducing the roughness coefficients for both rangeland and cropland areas. The overall results confirmed the applicability of the AnnAGNPS model to the experimental conditions.