Effect of DEM Resolutions in the Runoff and Soil Loss Predictions of the WEPP Watershed Model

Type of content
Journal Article
Publisher's DOI/URI
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Publisher
University of Canterbury. Natural Resources Engineering
Journal Title
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Date
2005
Authors
Cochrane, T.A.
Flanagan, D.C.
Abstract

Erosion prediction utilizing digital elevation models (DEMs) is a logical advancement for automating the simulation process for models such as the Water Erosion Prediction Project (WEPP). The effects of using different DEM resolutions on watershed simulations and the ability to accurately predict sediment yield and runoff from different rainfall event sizes were studied using three application methods and data from six research watersheds. Simulating watersheds with a range of resolutions can help address the problem of deciding what topographic DEM resolution is ideal for model simulations of the watershed outlet, the end of each hillslope, and along the slope profiles. The three application methods studied here were: (1) Hillslope − Chanleng, (2) Hillslope − Calcleng, and (3) Flowpath. The two Hillslope methods use a representative slope profile to represent each hillslope in the watershed, and the Flowpath method uses all of the individual flowpaths as model input for WEPP simulations. Results show that the Hillslope methods were not significantly influenced by DEM resolutions; however, there was an observable interaction between resolutions and the Flowpath method. Large rainfall events were predicted better than small events, but fine DEM resolutions did not improve predictions of either large or small rainfall events. Using coarse DEM resolutions for the topographic input will not decrease the accuracy of erosion prediction using the WEPP model and the Hillslope methods, unless the coarseness of the DEM compromises the delineation of the watershed or hillslopes.

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Citation
Cochrane, T.A., Flanagan, D.C. (2005) Effect of DEM Resolutions in the Runoff and Soil Loss Predictions of the WEPP Watershed Model. Transactions of the ASAE, 48(1), pp. 109-120.
Keywords
Digital Elevation Models, geographic information systems, soil erosion modeling, Water Erosion Prediction Project
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
Field of Research::07 - Agricultural and Veterinary Sciences::0701 - Agriculture, Land and Farm Management::070105 - Agricultural Systems Analysis and Modelling
Field of Research::09 - Engineering::0907 - Environmental Engineering
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