The Use of Sediment Tracers in Watershed Processes

This paper reports the results of soil biogeochemical analyses (e.g. organic matter, clay%, sand%, CEC, pH, etc.) performed to characterize the biogeochemical properties of soils in the Upper South Amana area, a sub-catchment of the Clear Creek Watershed. Most of these properties are in turn used as inputs to the WEPP (Water Erosion Prediction Project) upland erosion model to predict sediment erosion rates. WEPP is a process-based, event-based, distributed parameter, water flow driven erosion prediction model. Climatic data and Digital Elevation Models (DEM) are also incorporated in the model along with the biogeochemical properties of the soils. The WEPP model is first calibrated and then a sensitivity analysis is performed to identify the governing parameters of upland erosion in the Upper South Amana Area. Such comparison will further strengthen the argument regarding event-based simulations vs. continuous based simulations. The results of this study will be used for supplementary investigation of physical mechanisms of upland erosion processes.