Modeling soil erosion and sediment transport from fires in forested watersheds of the South Carolina Piedmont
Forested watersheds in the Southeastern U.S. provide high quality water vital to ecosystem integrity and downstream aquatic resources. Excessive sedimentation from human activities in forest streams is of concern to responsible land managers. Prescribed fire is a common treatment applied to Southeastern piedmont forests and the risk of wildfire is becoming increasingly important under the threat of changing climate. Measuring and predicting the amount of runoff and erosion from fire induced forested watersheds is difficult and costly. Erosion simulation models assist in relieving the time and resources consumed predicting these effects. The process-based Water Erosion Prediction Project (GeoWEPP) is widely used in the Western U.S. to predict erosion from forest fires. The objective of this study was to evaluate the effectiveness of the Geo WEPP model in predicting sedimentation amounts from low, moderate and high intensity forest fires on pine stands of the Sumter National Forest in the piedmont region of South Carolina. Modeling results were compared to observed sediment production of 48 small-scale plots within the watersheds. Results from the simulations conclude that the Geo WEPP model satisfactorily predicted erosion amounts during unburned, low and moderate intensity forest fire conditions. We found that low intensity fires may not elevate sediment loading above tolerable rates, however, severe fires can cause soil erosion and sediment loading at levels of concern in water quality degradation. Land topography, fire intensity, storm intensity and soil type are key variables to predicting soil erosion and runoff. This study is the first to evaluate the effectiveness of the Geo WEPP model in predicting runoff and sedimentation in Southeastern piedmont watersheds.