Sediment Source Ascription of Forest Roads in the Upper Little Tennessee River Basin

The purpose of this project was to better understand if geochemical fingerprinting could determine sediment provenance for catchments with and without USDA Forest Service Roads. Sediment source ascription is valuable because sediment is one of the most important non-point source pollutants affecting surface waters in the southeastern United States. Gravel roads represent surfaces of geologically fresh material, rich in weatherable minerals, some of which are preserved in transport, and distinguishable in sediment deposits. Sediment samples were collected from sources of active erosion as well as within the channel near watershed outlets. Analysis for 33 elements, along with statistical separation allowed provenance to be determined for roads and stream banks. Discriminant analysis shows that road sediment is differentiated by P, Mo, and Na. Bank sediment can be distinguished by Pb. Road sources accounted for 39 to 61 percent of bedload sediment and the remainder was from banks.