Assessing water erosion in small watersheds using WEPP with GIS and digital elevation models
Watershed erosion is a cause of nonpoint source pollution that can have an adverse effect on downstream and ecosystem water quality. Three different approaches using geographical information systems (GIS) and digital elevation models (DEMs) are described and evaluated for applying the Water Erosion Prediction Project (WEPP) model to assess water erosion in small watersheds. The first approach describes a typical application of the watershed version of WEPP using GIS only as an aid for construction of required input files. The second approach presents an automated method for the application of WEPP through the extraction of hillslopes and channels from DEMs. The third approach was WEPP model simulations on all possible flowpaths within a watershed. The three methods were applied to six research watersheds: one from Treynor, IA, two from Watkinsville, Ga., and three from Holly Springs, Miss. A statistical analysis for all methods and watersheds compared the predicted vs. measured runoff and sediment yield from watershed outlets on an event-by-event basis for runoff and sediment loss. The results indicate that the automatic hillslope method performs as well as the manual technique for all watersheds. A comparison of erosion from only hillslopes for all three methods indicates that the flowpath method is statistically comparable to the other methods. Results of the analysis suggest that, given an accurate DEM and valid input data for a simple watershed, the automatic hillslope method can be used to facilitate the application of the watershed version of WEPP, and that predictions should be comparable to an expert user's application of WEPP.
- Research Organization:
- Purdue Univ., West Lafayette, IN (US)
- OSTI ID:
- 20012744
- Journal Information:
- Journal of Soil and Water Conservation, Vol. 54, Issue 4; Other Information: PBD: 1999; ISSN 0022-4561
- Country of Publication:
- United States
- Language:
- English
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