Skid Trail Stream Crossing Closure Techniques for Protecting Water Quality

The impact of forest roads and skid trails on stream health is being increasingly scrutinized. Forest roads and skid trails have repeatedly been identified as forest operations having the greatest potential to produce sediment by way of non-point source pollution. The stream crossing portion of a skid trail is where sediment delivery is most likely to occur. Forestry Best Management Practices (BMPs) have been developed by most states to reduce both erosion and sedimentation. In general, BMPs have been proven to be effective. Few studies have quantified the impact of various levels of BMPs on sedimentation. In this study, three replications of three skid trail stream crossing BMP treatments were monitored following skidder bridge removal to determine their efficacy in reducing sedimentation: slash, mulch, and mulch plus silt fence. Water samples were collected upstream and downstream of each crossing daily for one year following timber harvesting. Samples were evaluated for total suspended solids. Results indicate that both slash and mulch treatments applied to the stream crossing approach after skidder bridge removal are effective at reducing stream sedimentation after harvest. The mulch plus silt fence treatment allowed the most sediment to enter the stream at the approach, perhaps due to silt fence installation disturbances. We do not recommend using silt fences directly adjacent to a stream bank, if other alternatives exist.