Modeling changes in rill erodibility and critical shear stress on native surface roads

This study investigated the effect of cumulative overland flow on rill erodibility and critical shear stress on native surface roads in central Idaho. Rill erodibility decreased exponentially with increasing cumulative overland flow depth; however, critical shear stress did not change. The study demonstrated that road erodibility on the studied road changes over the course of one or more consecutive overland flow events. Therefore, model simulations that fail to take into consideration this change will probably over-estimate sediment yields. An exponential function describing the relationship between rill erodibility and cumulative overland flow depth is presented as a basis for future model development for simulating erosion on native surface roads. Copyright © 2008 John Wiley & Sons, Ltd.