Abstract: | In terms of erosion and elevated suspended sediment concentrations, road construction has a major impact on the environment, which is described in this paper. In the Andheri Khola catchment, Nepal, the sediment regime of a stream at different locations within the catchment suddenly changed between 1999 and 2000. The only explanation for this change was the construction of the Bardibas‐Dhulikhel highway, which was initiated in this area in January 2000 and completed in March 2000. The changes in suspended sediment concentration could be shown both visually as well as statistically at three different locations in the catchment with a catchment without any impact of the road as a control. Other possible reasons for the change could be excluded by using the available data from the catchment. The impact of the road was estimated to range from 300 to 500 per cent in terms of change in sediment yield per annum. Copyright © 2006 John Wiley & Sons, Ltd. |