ABSTRACT:
Grid- and contour-based digital elevation models are readily available. Terrain analysis methods use these data to estimate the topographic attributes of a catchment, many of which are essential parameters in hydrologic and water quality models. Integration of these techniques into hydrologic and water quality models permits better representation of the effects of three dimensional terrain on runoff and erosion processes and improves the efficiency of topographic data input. Terrain analysis methods were interfaced with the agricultural nonpoint source (AGNPS) pollution model to demonstrate how this integration can be achieved. Two terrain-enhanced versions of the AGNPS model were developed: AGNPS-C, a contour-based version, and AGNPS-G, a grid-based version. These terrain-enhanced models automatically generate the cell network, the cell connectivity, and the required topographic parameters. Peak discharge predicted by the three versions of the AGNPS model for five storms on a small catchment near Treynor, Iowa, were similar, but sediment yield predictions exhibited some differences. Sensitivity analysis shows that flow path lengths and contributing areas computed by the terrain analysis depend on cell size.
Footnotes
John Panuska is a project engineer with Short-Elliott-Hendrickson, Inc., and Ian D. Moore holds the Jack Beale chair of water resources with the Centre for Resource and Environmental Studies, The Australian National University, Canberra, ACT, 2601, Australia; Panuska was a graduate assistant and Moore was an associate professor in the Department of Agricultural Engineering, University of Minnesota, St. Paul, Larry A. Kramer is an agricultural engineer with the Cropping Systems and Water Quality Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Council Bluffs, Iowa 51503. Published as Paper No. 17,804 of the Scientific Journal Series of the Minnesota Agricultural Experiment Station on research conducted under Minnesota Agricultural Experiment Station Projects MIN-12-055, Minn-12-30, and MIN-12-056 (Regional Project S-211). This study was funded in part by a grant provided through the Minnesota Water Resources Research Center from the U.S. Department of the Interior, U.S. Geological Survey.
- Copyright 1991 by the Soil and Water Conservation Society
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