Location: National Soil Erosion ResearchTitle: Applying online WEPP to assess forest watershed hydrology Author
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2013
Publication Date: 4/26/2013
Citation: Dun, S., Wu, J., Elliot, W.J., Frankenberger, J.R., Flanagan, D.C., McCool, D.K. 2013. Applying online WEPP to assess forest watershed hydrology. Transactions of the ASABE. 56(2):581-590. Interpretive Summary: Forested watersheds occupy large areas adjacent to many of the Great Lakes in the United States, and sediment from them can impact the lakes. Different types of forest management operations as well as the occurrence of wildfire can affect the risk of off-site losses of sediment from soil erosion. Soil erosion models are commonly used to assess the risk of runoff, erosion, and sediment losses from forested regions, as it is impractical and extremely expensive to monitor large forested watersheds. Additionally, models can be used to identify “hotspots”, or regions with likely high erosion rates, as well as evaluate the relative effects of different placements and types of soil conservation practices. This paper describes an online web-based WEPP (Water Erosion Prediction Project) model interface being developed for use in Great Lakes forested watersheds. In the study here, the performance of the model at predicting the runoff and sediment losses from two test forested watersheds in West Virginia was examined, and found to be satisfactory. This work impacts foresters, scientists, agency personnel (EPA, FS, NRCS, ARS, etc.), and others, interested in applying this new tool to assess runoff and sediment losses in forested watersheds. The results give confidence that WEPP can be successfully applied in these types of simulations.
Technical Abstract: A new version of the online Water Erosion Prediction Project (WEPP) GIS interface has been developed to assist in evaluating sediment sources associated with forests and forest management within the Great Lakes Basin. WEPP watershed structure and topographical inputs for each watershed element are generated from the USGS 30-m National Elevation Data, soil inputs are automatically retrieved from the USDA NRCS SSURGO database, and landuse and management inputs are selected from the WEPP database based on the USGS land cover. Additionally, surface cover and soil properties of the WEPP management file and soil file can be customized to represent site-specific conditions. Daily climate inputs are generated from the long-term climate parameters using CLIGEN, an auxiliary stochastic climate generator. Long-term observational data from two mature forest watersheds of the Fernow Experimental Forest, West Virginia, were used for assessing the online WEPP GIS interface. Online WEPP simulations were carried out and the model performance was examined by comparing simulated and observed streamflow data and sediment yield derived from the observed stream chemistry data. The online WEPP model reasonably simulated average annual runoff and the annual maximum runoff series for both watersheds. Sediment yield was slightly under-predicted for annual average and over-predicted for the annual maximum series. In addition, the simulation results adequately reflected the differences between the two watersheds in their hydrological characteristics.