Effect of Lowered Tire Pressures on Road Erosion

The effect of tire pressure on sediment produced by loaded logging trucks operating on low-quality aggregate surfaced roads is analyzed. Rainfall and runoff were measured for three winter seasons with logging truck traffic. Sediment eroded from the road surface from moderately reduced tire pressure road sections averaged 45 percent less than from the highway tire pressure sections. An average reduction of 80 percent was measured from the section used by trucks operating with low tire pressure sections. Because the processes responsible for sediment reduction are not site specific, lowering tire pressures in logging trucks on unpaved roads can reduce the sediment loss from many unpaved road surfaces. The results were used to calibrate the Water Erosion Prediction Project (WEPP) model. Once calibrated, the model estimated the sediment reduction expected at representative locations for all national forests. The WEPP model demonstrated its ability to be helpful in estimating the sediment reduction from forest roads.