Road Ecology Center

Sediment from gravel roads has degraded stream health in the southern Appalachians. National Forests initiated road reconstruction projects to reduce stream sedimentation. We monitored runoff water quality, before and after road reconstruction, from a wide variety of roads. Treatments included ditch obliteration, out-sloping, culvert removal, broad-based dips, and hay bales. Pre-treatment sediment yield generally increased with usage levels. Sediment yields following reconstruction were approximately one half of pretreatment levels. We monitored total suspended solids (TSS) and total petroleum hydrocarbons (TPH) from gravel and paved roads to quantify the effects of paving on water quality. While [TSS] tended to be lower on the paved road, they were not significantly lower than those of the maintained gravel roads. [TPH] from the two-year-old surface were just above detection limits (well below standards) at the road edge and not found downstream. TPH from the newly paved road adsorbed to sediments and did not move to the stream.