Abstract
Expanding mountain road networks in developing countries significantly increase the risk of landslides and sedimentation, as well as create vulnerabilities for residents and aquatic resources. We measured landslide erosion along seven road segments in steep terrain in the upper Salween River basin, Yunnan, China and estimated sediment delivery to channels. Landslide erosion rates along the roads ranged from 2780 to 48 235Mgha−1 yr−1, the upper end of this range being the highest rate ever reported along mountain roads. The two roads with the highest landslide erosion (FG1= 12966Mgha−1 yr−1 ; DXD= 48235Mgha−1 yr−1) had some of the highest sediment delivery rates to channels (about 80 and 86%, respectively). Overall, three times more landslides occurred along cutslopes compared to fillslopes, but fillslope failures had a combined mass> 1.3 times that of cutslope failures. Many small landslides occurred along road cuts, but these were often trapped on the road surface. Given the magnitude of the landslide problem and the lack of attention to this issue, a more sustainable approach for mountain road development is outlined based on an analysis of landslide susceptibility and how thresholds for landslide trigger mechanisms would be modified by road location and construction techniques.