Impact of Digital Elevation Model Grid Size on Extracted Drainage Parameters

by J. Garbrecht, Natl Agricultural Water Quality Lab, Durant, United States,
L. Martz, Natl Agricultural Water Quality Lab, Durant, United States,



Document Type: Proceeding Paper

Part of: Engineering Hydrology

Abstract:

The dependence of extracted drainage network properties on the spatial resolution of DEMs is investigated for a study basin. A series of raster DEMs of increasing cell size is generated by grid cell aggregation. Several drainage network properties are extracted from these DEMs and changes in these properties with increasing DEM cell size are examined. For grid coefficients less than 0.05 the extracted properties generally remain within about 10% of those extracted from the finest DEM. For networks with sinuous channel patterns and for properties related to channel length or to small drainage features, the grid dependency can start at grid coefficients smaller than 0.05. The dependency is introduced by the inability of a DEM to accurately reproduce such drainage features as their size approaches the spatial resolution of the DEM.

Subject Headings: Drainage | Grid systems | Discrete element method | Model accuracy | Computer models | Spatial analysis | Parameters (statistics)

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