Minimizing the Impacts of the Forest Road System
Sediment movement from forest road systems is a major concern in forest management due to the degrading impacts of stream sedimentation. Controlling sediment movement from road systems is a key objective to achieve the goat of reducing the impact of forest management activities. Sediment control systems minimizing sediment travel distances downslope are likely essential to reducing the environmental impact of road systems. The USDA Forest Service Southern Research Station initiated a study in an attempt to evaluate alternative means of filtering sediment laden road runoff before it reaches the forest floor on the Tuskegee National Forest in Alabama. The effectiveness of four alternative road sediment control treatments: vegetation, riprap, sediment fences, and settling basins (detention ponds), in reducing sediment export to the forest floor were evaluated over a 42-month period. The sediment basin, sediment fence, and vegetation treatments were similar in eff icacyto reduce runoff concentrations with 89,85, and 66 percent reductions. Riprap was significantly less effective than the sediment basin and sediment fence in reducing concentrations over the study period. The findings suggest that the sediment basin and sediment fence treatments, with concentration reductions greater than 80 percent, may have some applicability as primary sediment control structures on forest road turn-outs.