Natural and anthropogenic controls over suspended sediments within a mountainous Appalachian watershed: implications for watershed restoration

摘要

The upper Elk River (620 km2), located in mountainous east-central West Virginia, is one of the premier cold-water fisheries in the eastern United States. However, sediment run-off from both forestry and non-forestry-related disturbance has the potential to threaten the quality of wild trout populations. General linear models were used to link spatial and temporal variation in total suspended solid (TSS) concentrations throughout the watershed to natural (i.e. landform and geology) and anthropogenic(forest management practices, other land-use disturbance residential and commercial development, agriculture, and recreation, census roads) landscape attributes. In addition, through a unique paired sampling design, we tested the hypothesis that increasing levels of disturbance (i.e. forest management and other land use activities) within a watershed would result in a proportional increase in TSS concentrations. Spatial variation in TSS concentration was found to primarily be explained by land-use disturbance (partial R2 = 0.66) and secondarily by forest management practices (R2 = 0.13) and road area (R2 = 0.08). Results of a paired sampling design further indicated that significant increases in TSS concentrations were the result of intense land-usedisturbance associated with activities other than forest management. Temporal variability (i.e. CV) in TSS was primarily related to dry flat area (partial R = 0.28) and percent calcareous bedrock (R2 = 0.21), suggesting natural sedimentation processes associated with karst geologies may exacerbate effects of anthropogenic disturbance. These results suggest that forestry-related best management practices being used in this mountainous region were effective in reducing sediment loads to nearby waterbodies, and improved management of non-forestry disturbance may be needed to protect this valuable fishery from sediment-related impacts.