In the Bridger-Teton National Forest, Wyoming, WEPP allowed planners to compare the advantages of graveling a road in a sensitive watershed to installing water bars and tail drains from the continuous road ditches. In this case, it was found that the most effective way to reduce sedimentation was to install waterbars and tail drains at appropriate locations, rather than gravel the entire road surface. With continuous ditches, gravel would essentially lead to the substitution of road ditch erosion for road rut erosion. We are carrying out a WEPP computer study to determine the relationships among road topography, side-hill topography, soils and climate in sediment delivery from roads. The results show that generally the effects of topography and soils are as expected, but that the effects of climate are complex.
Some climates are rainfall driven, and others are snow melt driven.
This difference has a major impact on the rate of road erosion, and the likelihood of sediment delivery acoss any buffer zone downhill from a road. We have no workshops planned at this time. If regions or groups wish to have a workshop on WEPP, please contact us, and we will see if we can arrange a workshop to meet their specific needs. It is available on a CD ROM, which includes the documentation, all of the climates for the USA and a large soils data base. We have some copies of the CD for distribution to Forest Service users.