SEDIMENT PRODUCTION AND DOWNSLOPE SEDIMENT TRANSPORT FROM FOREST ROADS IN GRANITIC WATERSHEDS

A mapping technique was used to measure the annual downslope depositio n of granitic sediments eroded from forest roads on three headwater wa tersheds in the mountains of central Idaho. Frequency distributions we re developed to determine sediment travel distance, and a dimensionles s relationship was developed to describe the relation between the perc entage of total volume and total length of sediment deposit. By combin ing the two relations, land managers can assess the risk of sediment r eaching streams to help guide road location and design.