Influence of forest roads and BMPs on soil erosion
Mitigating sediment export from the forest road prism and potential delivery to forest streams will require a more complete prospective on forest road erosion and benefit of BMPs in reducing the risk of degrading environmental impacts. Sediment control systems have clearly been presented as effective in minimizing sediment travel distances downslope and are likely the key to reducing the environmental impact of road systems. In an attempt to address the questions related to the impact of forest roads and the effectiveness of BMPs to control sediment and its introduction to the forest floor downslope, a study was installed in northeast Georgia within the Chattooga River Ranger District of the Chattahoochee-Oconee National Forest. This paper reports the storm runoff and sediment loading results of a 6-year study that evaluates the effectiveness of road BMPs in controlling sediment movement from the road prism. The three sediment control treatments investigated were hay bale barrier, sediment basin, and sediment basin with riser control. The mean runoff reduction ratios (P=0.634) and runoff coefficients (P>0.098) for road sections was not detected as significantly different for the treatments. Outlet runoff volume from the sediment basin with riser control was found to be significantly less than the other treatments. Mean trap efficiency for the sediment basin with riser control, haybale, and sediment basin treatments were 99, 97, and 94 percent, respectively. Based on this analysis, no differences were detected in the haybale and sediment basin with riser control and sediment basin treatment. The fact that the haybale treatment was not different from the other treatments likely indicates that runoff reductions found for all treatments resulted in significant reductions in sediment transport.