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United States Department of Agriculture

Agricultural Research Service

Title: Simulation of Hillslope Soil Erosion Patterns with the Wepp Model in Tanzania

Authors
item Vigiak, O - WAGENINGEN UNIVERSITY
item Chitrakar, S - WAGENINGEN UNIVERSITY
item Sterk, G - WAGENINGEN UNIVERSITY
item Flanagan, Dennis

Submitted to: ASA-CSSA-SSSA Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2004
Publication Date: October 1, 2004
Citation: Vigiak, O., Chitrakar, S., Sterk, G., Flanagan, D.C. 2004. Simulation of hillslope soil erosion patterns with the WEPP model in tanzania. ASA-CSSA-SSSA Proceedings. October 1-November 4, 2004, Spokane, Washington. 2004. CDROM.

Technical Abstract: The Water Erosion Prediction Project (WEPP) model simulates erosion processes along hillslope profiles. In this study, WEPP performance in depicting patterns of erosion and deposition along a slope was tested. Event based simulations were compared to observations of soil erosion along two longitudinal transects in the Tanzanian Highlands. Transects were comprised of different annual and perennial tropical crops, but had only a single soil type. Measurements of runoff and soil loss in Gerlach troughs at different transect positions allowed calibration of three important WEPP soil parameters: effective hydraulic conductivity, soil moisture and interrill erodibility. Model calibration on 4 events yielded a root mean square error (RMSE) of soil loss predictions of 1.14. Model validation on 5 other events yielded a RMSE of 0.15, confirming the simulation goodness-of-fit. Finally, model simulations of erosion and deposition along the hillslope were compared to the soil erosion pattern observed by qualitative surveys. WEPP simulations showed generally good agreement with the observations, but had less agreement in the lower transect sections, where soil loss was overpredicted. This was acceptable when considering that transect lengths (above 200 m) were greater than the WEPP recommended limits. In conclusion, the WEPP model performed well in the Tanzanian Highland environment.

Last Modified: 4/24/2014
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