ARS | Publication request: SMALL WATERSHED MODELING WITH WEPP USING GRID BASED DEMS AND GIS

Submitted to: American Society of Agricultural Engineers Meetings Papers
Publication Type: Abstract Only
Publication Acceptance Date: July 19, 1999
Publication Date: N/A

Technical Abstract: Currently, a user applying the Water Erosion Prediction Project (WEPP) watershed model has to use topographical paper maps to manually delineate the watershed of interest, the channel network in the watershed, individual hillslopes, and a representative slope profile for each hillslope. This process of discretization is time consuming for the user and can be a subject of discrepancy and variability between users. An interface between WEPP and a GIS has been created to facilitate the discretization process. This interface uses the TOPAZ algorithms as well as newly developed algorithms to identify the watershed, channel network, hillslopes, and representative slope profiles from digital elevation models (DEMs). Furthermore, a more detailed method of applying WEPP on a flow-path by flow-path basis is described. These automated methods of applying WEPP to watersheds were tested using six research watersheds, the largest one being in Treynor, Iowa, measuring 29 ha and having 6 years of available daily measured data. The other five watersheds, three in Holly Springs, Mississippi and two in Watkinsville, Georgia, have areas between 0.59 and 2.7 ha and have 3 to 11 years of measured daily data. Comparisons between predicted and measured event runoff and sediment loss are presented for each of the automated methods.