Determining soil erodibility of forest roads

Abstract

Soil loss was measured on selected unsurfaced forest roads in Idaho and Colorado, using a rainfall simulator. From the data collected, both flow-induced and raindrop-induced interrill erodibility parameters were determined. Each forest road site consisted of one 5 m² and on 1 m² plot which simultaneously received artificial rainfall. Soil loss from the small plots was attributed solely to detachment by raindrops. The larger 5 m² plots may include some flow-induced soil loss. A method was developed to apportion the erosion from the 5 m² plots between flow-induced and raindrop-induced soil loss. Four different models of raindrop-induced erodibility and three different models of flow-induced erodibility were compared. Those considered most applicable to forest road conditions were suggested for further use in an erosion model for disturbed forestlands. This study serves an an important contribution in developing such a model by providing initial estimates of interrill erodibility parameters for forest road conditions.