Road Ecology Center

The Coweeta Hydrologic Laboratory, USFS Southern Research Station, worked with state and local agencies and various organizations to provide guidance and tools to reduce sedimentation and facilitate restoration of the 1900km2 Conasauga River watershed in northern Georgia and southern Tennessee. The Conasauga River has the most diverse aquatic ecosystem of any river in the region and is currently being considered for designation as a Federal wild and scenic river. The watershed is encircled and dissected by highways and roads, and receives intense recreational, industrial, and agricultural use from the surrounding human population. Unpaved roads have been found to account for more than 80 percent of stream sedimentation in the forested lands of this region. Collaborative efforts of research and management focused on developing sediment yield models, prioritizing road restoration, and reducing sediment yields from roads to streams. Model development facilitated identification of highly erosive roads and prediction of sediment yield reductions following reconstruction of forest roads. We monitored sediment yield and transport from a wide variety of existing forest roads during autumn 2001. We used these data for model validation. We then used the model to characterize roads by erosion susceptibility and to prioritize roads for reconstruction. During the summer of 2002, we completed reconstruction and installation of best management practices along more than 20 miles of forest roads. We monitored sediment yield from these roads through autumn 2002. Simulated estimates of sediment yield from the reconstructed roads were severely limited by the resolution and quality of available data and the sediment transport algorithms employed in the model. Despite a 46 percent increase in rainfall from the pre to post-treatment period, road reconstruction reduced sediment yield by 70 percent.