The objective of this work was to test the WEPP model (Water Erosion Prediction Project), by comparing experimentally observed runoff volume and soil loss in forest road segments under normal rainfall, with 1 and 7% slopes and lengths of 20 and 40 m, and those predicted by the WEPP, aiming to develop a Brazilian model of erosion prediction on forest roads. To determine the amount of eroded matter, 209.25 l capacity collector drums were placed on the lower level of the road segment. PVC pipes of 2 inches were connected to the drums to collect sediments from the road. Openings at the same height and size were made on the drums, located at 0.65 m from the bottom of the first drum and at 0.60 m from the bottom of the second drum, which functioned as a Geib divisor. In the 20 and 40 m long plots five and seven openings were made, respectively, on the first and second drums, with the third drum being used to collect the runoff excess from the second drum. The drums were connected in series through 2 inch - PVC pipes. Data of volume and intensity of daily precipitation were obtained by means of pluviometers and pluviographs. The period of data collection was one year, concentrated in the rainy season. Files on climate, precipitation, soil, slope and segment length were introduced and adapted to the WEPP model erosion prediction model to test it, aiming to elaborate a model suited to the Brazilian forest conditions.
WEPP; forest road; runoff volume; soil loss
