A gap exists in the understanding of the effectiveness of forest road best management practices (BMP) in controlling sediment movement and minimizing risks of sediment delivery to forest streams. The objective of this paper is to report the findings of investigations to assess sediment travel distances downslope of forest roads in the Appalachian region, relate sediment travel distances to BMP recommendations, and describe the deposition patterns within buffer zones. A total of 164 randomly selected sediment deposition zones were measured downslope of the road lead-off ditch structures for each forest. The mean distance sediment was deposited within buffer zones was 20 m for the Chattahoochee National Forest (Georgia) and 41 m for the Talladega National Forest (Alabama). Sediment transport distances were <30 m for 38 and 88 percent of sites evaluated on the National Forests in Alabama and Georgia, respectively. A small percentage (15 percent) of sediment from road sections terminated in streams downslope of the road sections in this investigation. Results indicate that current road BMPs are somewhat effective in reducing risks of road to steam connectivity in most cases. However, the deposition lengths within the buffers for both forests were >20 m which may exceed the buffer zone width requirements in the States in this investigation and many States in the United States. This research indicates that the connectivity issue requires additional research that specifically focuses on quantifying the fraction of forest road erosion reaching stream systems which include intermittent and perennial streams.
Grace, Johnny M., III; Zarnoch, Stanley J. 2013. Influence of forest road buffer zones on sediment transport in the Southern Appalachian Region. In: Guldin, James M., ed. 2013. Proceedings of the 15th biennial southern silvicultural research conference. e-Gen. Tech. Rep. SRS-GTR-175. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 487-493.