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Effects of DEM resolution on forest hydrologic and erosion prediction using WEPP
Zhang, J.X.; Wu, J.Q.; Elliot, W.J.; Dun, S.; Chang, K. 2006.
Effects of DEM resolution on forest hydrologic and erosion prediction using WEPP.
Written for presentation at the 2006 ASABE Annual International Meeting.
Sponsored by ASABE, Portland Convention Center, Portland, OR. 9 - 12 July 2006.
ASABE Paper No. 062179.
American Society of Agricultural and Biological Engineers.
Keywords: forest watershed, water erosion modeling, WEPP, GIS, DEM, LiDAR
Links:
Abstract:
The recent modification of WEPP (Water Erosion Prediction Project) has improved the
original model.s applicability to hydrology and erosion modeling in forest watersheds. To generate
reliable topographic and hydrologic inputs for the WEPP model, carefully selecting Digital Elevation
Models (DEMs) with appropriate resolution and accuracy is essential because topography is a major
factor controlling water erosion. LIght Detection and Ranging (LiDAR), a new remote sensing
technology, provides an alternative for generating fine and high-quality DEMs. This study applies
WEPP (v2006.201) for hydrological and erosion simulation under forest conditions and evaluates the
effects of DEM resolution and accuracy on watershed hydrology and water erosion prediction at a
watershed scale. Stream flow and total suspended solids (TSS) in two small forest watersheds
located in northern Idaho were collected and processed. A total of six DEMs from three sources
(NED, SRTM, and LiDAR) at three resolutions (30 m, 10 m, and 4 m) were obtained and used to
calculate topographic parameters as inputs to the WEPP model. WEPP-simulated hydrologic and
erosion results using the six DEMs were compared with the field-observed data. For both study
watersheds, DEMs with different resolutions and sources generated varied topographic and
hydrologic attributes, which in turn led to significantly different erosion predictions by WEPP.
Moscow FSL publication no. 2006k
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